EP1971422A1 - Gas separation membranes containing a microporous silica layer based on silica doped with a trivalent element - Google Patents
Gas separation membranes containing a microporous silica layer based on silica doped with a trivalent elementInfo
- Publication number
- EP1971422A1 EP1971422A1 EP06847128A EP06847128A EP1971422A1 EP 1971422 A1 EP1971422 A1 EP 1971422A1 EP 06847128 A EP06847128 A EP 06847128A EP 06847128 A EP06847128 A EP 06847128A EP 1971422 A1 EP1971422 A1 EP 1971422A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- silica
- support
- boron
- deposited
- doped
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 239000012528 membrane Substances 0.000 title claims abstract description 91
- 238000000926 separation method Methods 0.000 title claims abstract description 55
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 title claims description 164
- 239000000377 silicon dioxide Substances 0.000 title claims description 81
- 238000000034 method Methods 0.000 claims abstract description 56
- 239000007789 gas Substances 0.000 claims abstract description 49
- 229910052796 boron Inorganic materials 0.000 claims abstract description 31
- 229910052734 helium Inorganic materials 0.000 claims abstract description 30
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims abstract description 28
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 27
- 239000010703 silicon Substances 0.000 claims abstract description 27
- 239000001307 helium Substances 0.000 claims abstract description 26
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 claims abstract description 26
- 239000002243 precursor Substances 0.000 claims abstract description 24
- RMAQACBXLXPBSY-UHFFFAOYSA-N silicic acid Chemical compound O[Si](O)(O)O RMAQACBXLXPBSY-UHFFFAOYSA-N 0.000 claims abstract description 24
- -1 silicon alkoxide Chemical class 0.000 claims abstract description 23
- 229910052739 hydrogen Inorganic materials 0.000 claims abstract description 19
- 230000008021 deposition Effects 0.000 claims abstract description 18
- 238000010438 heat treatment Methods 0.000 claims abstract description 16
- 239000001257 hydrogen Substances 0.000 claims abstract description 15
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 claims abstract description 12
- 230000003301 hydrolyzing effect Effects 0.000 claims abstract description 6
- 238000004519 manufacturing process Methods 0.000 claims abstract description 4
- 239000010410 layer Substances 0.000 claims description 75
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 29
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 28
- 238000000151 deposition Methods 0.000 claims description 22
- 230000008569 process Effects 0.000 claims description 22
- 150000004703 alkoxides Chemical class 0.000 claims description 15
- 239000002689 soil Substances 0.000 claims description 13
- 230000007062 hydrolysis Effects 0.000 claims description 11
- 238000006460 hydrolysis reaction Methods 0.000 claims description 11
- 229910052810 boron oxide Inorganic materials 0.000 claims description 10
- JKWMSGQKBLHBQQ-UHFFFAOYSA-N diboron trioxide Chemical compound O=BOB=O JKWMSGQKBLHBQQ-UHFFFAOYSA-N 0.000 claims description 10
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims description 8
- 239000002253 acid Substances 0.000 claims description 8
- 239000000919 ceramic Substances 0.000 claims description 8
- 150000001875 compounds Chemical class 0.000 claims description 7
- 239000008246 gaseous mixture Substances 0.000 claims description 6
- 238000011065 in-situ storage Methods 0.000 claims description 5
- 239000002344 surface layer Substances 0.000 claims description 5
- 239000007864 aqueous solution Substances 0.000 claims description 3
- 125000004432 carbon atom Chemical group C* 0.000 claims description 3
- 238000000746 purification Methods 0.000 claims description 3
- IJKVHSBPTUYDLN-UHFFFAOYSA-N dihydroxy(oxo)silane Chemical compound O[Si](O)=O IJKVHSBPTUYDLN-UHFFFAOYSA-N 0.000 claims description 2
- 125000001183 hydrocarbyl group Chemical group 0.000 claims description 2
- 238000009434 installation Methods 0.000 claims description 2
- 239000012535 impurity Substances 0.000 abstract description 5
- 229910052782 aluminium Inorganic materials 0.000 abstract description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 abstract description 3
- 239000004411 aluminium Substances 0.000 abstract 1
- 239000010408 film Substances 0.000 description 18
- 239000002609 medium Substances 0.000 description 18
- 239000011148 porous material Substances 0.000 description 15
- BOTDANWDWHJENH-UHFFFAOYSA-N Tetraethyl orthosilicate Chemical compound CCO[Si](OCC)(OCC)OCC BOTDANWDWHJENH-UHFFFAOYSA-N 0.000 description 10
- 230000015572 biosynthetic process Effects 0.000 description 9
- CPUDPFPXCZDNGI-UHFFFAOYSA-N triethoxy(methyl)silane Chemical compound CCO[Si](C)(OCC)OCC CPUDPFPXCZDNGI-UHFFFAOYSA-N 0.000 description 8
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 7
- 238000001035 drying Methods 0.000 description 7
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 6
- 238000005470 impregnation Methods 0.000 description 6
- 238000002454 metastable transfer emission spectrometry Methods 0.000 description 6
- 238000002360 preparation method Methods 0.000 description 6
- 238000005336 cracking Methods 0.000 description 5
- 230000007547 defect Effects 0.000 description 5
- 239000000203 mixture Substances 0.000 description 5
- 239000000243 solution Substances 0.000 description 5
- 230000008901 benefit Effects 0.000 description 4
- 238000010348 incorporation Methods 0.000 description 4
- 238000003980 solgel method Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 239000004215 Carbon black (E152) Substances 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 230000002378 acidificating effect Effects 0.000 description 3
- 125000000217 alkyl group Chemical group 0.000 description 3
- 238000006243 chemical reaction Methods 0.000 description 3
- 238000004132 cross linking Methods 0.000 description 3
- 238000009792 diffusion process Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 229930195733 hydrocarbon Natural products 0.000 description 3
- 150000002430 hydrocarbons Chemical class 0.000 description 3
- 150000002431 hydrogen Chemical class 0.000 description 3
- 238000007654 immersion Methods 0.000 description 3
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonium chloride Substances [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 description 2
- VHUUQVKOLVNVRT-UHFFFAOYSA-N Ammonium hydroxide Chemical compound [NH4+].[OH-] VHUUQVKOLVNVRT-UHFFFAOYSA-N 0.000 description 2
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 2
- 229910021529 ammonia Inorganic materials 0.000 description 2
- 235000011114 ammonium hydroxide Nutrition 0.000 description 2
- 229910052799 carbon Inorganic materials 0.000 description 2
- 230000001627 detrimental effect Effects 0.000 description 2
- 230000007717 exclusion Effects 0.000 description 2
- 239000011159 matrix material Substances 0.000 description 2
- 239000002808 molecular sieve Substances 0.000 description 2
- 229910017604 nitric acid Inorganic materials 0.000 description 2
- 239000002245 particle Substances 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000007873 sieving Methods 0.000 description 2
- 150000004756 silanes Chemical group 0.000 description 2
- 150000003384 small molecules Chemical class 0.000 description 2
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 description 2
- 238000005063 solubilization Methods 0.000 description 2
- 230000007928 solubilization Effects 0.000 description 2
- 238000001179 sorption measurement Methods 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 238000009997 thermal pre-treatment Methods 0.000 description 2
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- 230000032683 aging Effects 0.000 description 1
- 125000003545 alkoxy group Chemical group 0.000 description 1
- 238000004873 anchoring Methods 0.000 description 1
- 239000012736 aqueous medium Substances 0.000 description 1
- 125000004429 atom Chemical group 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 229910001593 boehmite Inorganic materials 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000011247 coating layer Substances 0.000 description 1
- 238000006482 condensation reaction Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 230000001934 delay Effects 0.000 description 1
- 238000010790 dilution Methods 0.000 description 1
- 239000012895 dilution Substances 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 230000004992 fission Effects 0.000 description 1
- 239000000446 fuel Substances 0.000 description 1
- 125000000524 functional group Chemical group 0.000 description 1
- 238000001879 gelation Methods 0.000 description 1
- FAHBNUUHRFUEAI-UHFFFAOYSA-M hydroxidooxidoaluminium Chemical compound O[Al]=O FAHBNUUHRFUEAI-UHFFFAOYSA-M 0.000 description 1
- 229910052500 inorganic mineral Inorganic materials 0.000 description 1
- 150000002605 large molecules Chemical class 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 229920002521 macromolecule Polymers 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000012982 microporous membrane Substances 0.000 description 1
- 239000011707 mineral Substances 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 125000000962 organic group Chemical group 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 238000004181 pedogenesis Methods 0.000 description 1
- 239000002574 poison Substances 0.000 description 1
- 231100000614 poison Toxicity 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 230000001737 promoting effect Effects 0.000 description 1
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 238000010992 reflux Methods 0.000 description 1
- 230000000717 retained effect Effects 0.000 description 1
- SCPYDCQAZCOKTP-UHFFFAOYSA-N silanol Chemical compound [SiH3]O SCPYDCQAZCOKTP-UHFFFAOYSA-N 0.000 description 1
- 150000004819 silanols Chemical class 0.000 description 1
- 238000007569 slipcasting Methods 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000004528 spin coating Methods 0.000 description 1
- 230000035882 stress Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000004381 surface treatment Methods 0.000 description 1
- 238000000427 thin-film deposition Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/22—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by diffusion
- B01D53/228—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by diffusion characterised by specific membranes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
- B01D67/0039—Inorganic membrane manufacture
- B01D67/0048—Inorganic membrane manufacture by sol-gel transition
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
- B01D67/0081—After-treatment of organic or inorganic membranes
- B01D67/0083—Thermal after-treatment
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D67/00—Processes specially adapted for manufacturing semi-permeable membranes for separation processes or apparatus
- B01D67/0081—After-treatment of organic or inorganic membranes
- B01D67/0088—Physical treatment with compounds, e.g. swelling, coating or impregnation
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/10—Supported membranes; Membrane supports
- B01D69/105—Support pretreatment
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/14—Dynamic membranes
- B01D69/141—Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D69/00—Semi-permeable membranes for separation processes or apparatus characterised by their form, structure or properties; Manufacturing processes specially adapted therefor
- B01D69/14—Dynamic membranes
- B01D69/141—Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes
- B01D69/1411—Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes containing dispersed material in a continuous matrix
- B01D69/14111—Heterogeneous membranes, e.g. containing dispersed material; Mixed matrix membranes containing dispersed material in a continuous matrix with nanoscale dispersed material, e.g. nanoparticles
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D71/00—Semi-permeable membranes for separation processes or apparatus characterised by the material; Manufacturing processes specially adapted therefor
- B01D71/02—Inorganic material
- B01D71/024—Oxides
- B01D71/027—Silicium oxide
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
- C04B35/14—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on silica
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B35/00—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/622—Forming processes; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products
- C04B35/624—Sol-gel processing
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/009—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone characterised by the material treated
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/45—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements
- C04B41/50—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with inorganic materials
- C04B41/5025—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements with inorganic materials with ceramic materials
- C04B41/5035—Silica
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/45—Coating or impregnating, e.g. injection in masonry, partial coating of green or fired ceramics, organic coating compositions for adhering together two concrete elements
- C04B41/52—Multiple coating or impregnating multiple coating or impregnating with the same composition or with compositions only differing in the concentration of the constituents, is classified as single coating or impregnation
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/80—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone of only ceramics
- C04B41/81—Coating or impregnation
- C04B41/85—Coating or impregnation with inorganic materials
- C04B41/87—Ceramics
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B41/00—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone
- C04B41/80—After-treatment of mortars, concrete, artificial stone or ceramics; Treatment of natural stone of only ceramics
- C04B41/81—Coating or impregnation
- C04B41/89—Coating or impregnation for obtaining at least two superposed coatings having different compositions
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2323/00—Details relating to membrane preparation
- B01D2323/48—Influencing the pH
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/00474—Uses not provided for elsewhere in C04B2111/00
- C04B2111/00793—Uses not provided for elsewhere in C04B2111/00 as filters or diaphragms
- C04B2111/00801—Membranes; Diaphragms
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
- C04B2235/30—Constituents and secondary phases not being of a fibrous nature
- C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
- C04B2235/3217—Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
- C04B2235/30—Constituents and secondary phases not being of a fibrous nature
- C04B2235/34—Non-metal oxides, non-metal mixed oxides, or salts thereof that form the non-metal oxides upon heating, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
- C04B2235/3409—Boron oxide, borates, boric acids, or oxide forming salts thereof, e.g. borax
-
- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
- C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
- C04B2235/30—Constituents and secondary phases not being of a fibrous nature
- C04B2235/44—Metal salt constituents or additives chosen for the nature of the anions, e.g. hydrides or acetylacetonate
- C04B2235/441—Alkoxides, e.g. methoxide, tert-butoxide
Definitions
- Gas separation membranes containing a silica-based microporous silica layer doped with a trivalent element a silica-based microporous silica layer doped with a trivalent element.
- the present invention relates to ceramic membranes, which are particularly suitable for gas separation by molecular sieving. More specifically, the invention relates to a method for depositing on a porous support a microporous layer based on amorphous silica substantially free of defects and stable at high temperature, thus giving access to membranes capable of ensuring effective separation of gas such as He or H 2 at temperatures of the order of 300 to 500 ° C.
- Gas separation by membranes is a technique widely used by the chemical industry, which has been particularly developed over the last 25 years.
- membrane used polymer, ceramic, dense or porous
- Molecular sieving is a technique that consists of separating gases present in mixture, using a difference in kinetic radius of the molecules to be separated.
- a microporous membrane is used which, under the effect of a difference in concentration or of partial pressure on either side of the membrane, allows the molecules with the smallest kinetic radius to diffuse preferentially and retains more the molecules of higher size.
- the membrane is used as molecular sieve, implementing a steric exclusion process ("pore size exclusion"), which inhibits or delays the diffusion of large molecules, thus promoting the diffusion of size the weakest.
- pore size exclusion a steric exclusion process
- adsorption phenomena on the surface of the membrane and / or in its pores
- the aforementioned transmembrane gas separation technique is very advantageous, especially insofar as it is modular and can be used in a continuous mode.
- this technique has, in practice, many fields of application.
- it is used for the separation of O 2 and N 2 from air, for the extraction of H 2 and N 2 in NH 3 production gases, or of H 2 in effluents with hydrocarbon base such as those resulting from refining processes, or else to remove CO 2 or NO in various gaseous effluents.
- the first parameter (i) is expressed by the "permeance" of the membrane, namely the amount of gas that the membrane allows to diffuse per unit area and time as a function of the applied pressure (expressed in mol.m- 2 . s "1 .Pa " 1 ).
- the second parameter (ii) is in turn reflected by the "selectivity" of the membrane, which is calculated by the ratio (in moles) of the quantity of small molecules (whose diffusion is sought) on the quantity of molecules. larger size (supposed to be retained) that are contained in the gas mixture that allows the membrane to diffuse.
- Membranes having a high separation efficiency in terms of permeance and selectivity are all the more difficult to obtain as the hydrodynamic diameter of the gases to be separated is small.
- the gas separation technique is particularly delicate when it is desired to carry out a separation of helium (kinetic diameter less than 0.30 nm) or of gas having similar kinetic diameters, such as H 2 or H 2 O , or their deuterated or tritiated equivalents.
- membranes comprising a separation layer having pores of extremely small dimensions, general less than 1 nm, and this in sufficient number to allow to obtain good permeation.
- Membranes of this type are currently known, including layers having a pore diameter of less than 1 nm.
- membranes of this type there may be mentioned membranes comprising a dense or microporous layer, such as a microporous layer based on silica (generally called MMS layer for the English “molecular sieve silica”).
- These membranes including a silica-based microporous layer are generally obtained by depositing a film of a silica sol on a porous support (for example an alumina-based support), then thermally treating the resulting film to convert it to a ceramic layer of microporous silica.
- the silica sol used in this context is generally obtained according to the so-called "sol-gel” technique, namely by hydrolyzing a silicon alkoxide, typically a tetraalkoxysilane such as TEOS (tetraethoxysilane, of formula Si (OEt) 4 ).
- a major problem encountered with membranes including silica-based microporous layers of the aforementioned type is their propensity for the presence of defects, which affect the selectivity of the membrane. These defects are mainly related to the rigidity of the silica network, which is a source of crack formation when the layer is subjected to stresses (which is particularly the case with membranes of large size necessary for gas separations at high temperatures. industrial scale) and / or when it is deposited on a support having surface irregularities (which is almost always the case).
- the cracks thus formed considerably affect the selectivity of the membrane, insofar as, rather than through the pores, the gases preferentially diffuse at the level of the cracks, which are of a nature to let species of greater kinetic diameter spread than the species to be separated.
- a solution that has been proposed to limit the phenomena of cracking in microporous layers of silica obtained by the sol-gel route consists in replacing all or part of the tetraalkoxysilanes used as precursors of the silica with alkoxysilanes carrying less than 4 reactive groups of silica. alkoxy type.
- MTES methyltriethoxysilane
- the microporous layer is to be used at high temperature, in particular at temperatures above 200 ° C., and more particularly at temperatures above 250 ° C.
- the microporous layers of silica which are obtained from alkyltrialkoxysilanes of type MTES specifically contain alkyl groups within their structure. Under the effect of an increase in temperature in the abovementioned ranges, these groups oxidize and are extracted with CO 2 starting, which induces the appearance of additional porosity in the layer, generally associated with embrittlement. this layer, likely to induce cracking. These different phenomena are detrimental to the selectivity of the gas separation.
- membranes based on a layer obtained from MTES are generally not suitable for effective separation of helium or H 2 at temperatures of the order of 300 0 C to 500 0 C, in particular under pressure.
- An object of the present invention is to provide a novel method for accessing gas separation membranes capable of separating helium or hydrogen at a temperature greater than 200 ° C., in particular at temperatures of the order of 300 to 500 0 C, and with a permeance and a selectivity preferably at least as good, and advantageously greater than those currently known separation membranes.
- the invention aims in particular to provide membranes having such properties of permeance and selectivity without having to implement the specific method described in US 2004/00380044.
- the subject of the present invention is a process for preparing a gas separation membrane, comprising the deposition of a film of a silica sol on a porous support, and then the heat treatment of the film thus deposited, characterized in that the silica sol which is deposited as a film on the porous support is prepared by hydrolyzing a silicon alkoxide in the presence of a doping amount of a precursor of an oxide of a trivalent element, this precursor being for example an alkoxide or an acid of the trivalent element.
- trivalent element is meant, in the sense of the present description, here an element whose atoms are capable of being inserted into the silica network with a degree of crosslinking at most equal to 3.
- the trivalent element used according to the present invention is boron (B). Boron is generally used as the only trivalent element. However, the boron may alternatively be used in admixture with other trivalent elements, for example aluminum.
- oxide precursor of a trivalent element denotes, within the meaning of the present description, a compound which is capable of forming an oxide based on the trivalent element under the conditions of hydrolysis of the alkoxide of silicon, which, in the method of the invention, allows to incorporate the trivalent element in the silica network during its formation.
- the precursor used for this purpose is an alkoxide of the trivalent element.
- the process of the present invention consists in preparing the membrane according to a conventional sol-gel technique, but by specifically performing the hydrolysis of the silicon alkoxide with the additional presence of a precursor an oxide of a trivalent element.
- the trivalent element alkoxide used is generally introduced into the hydrolysis medium of the silicon alkoxide in the form of at least one compound corresponding to the following formula (I):
- M denotes boron (B).
- the 3 R groups are identical or different (generally identical), and each represents a hydrocarbon chain comprising from 1 to 8 carbon atoms, preferably an alkyl group, preferably containing from 2 to 4 carbon atoms.
- the trivalent element alkoxide used can be formed in situ in the medium of the hydrolysis of the silicon alkoxide.
- boron oxide B 2 O 3 and an alcohol of formula ROH, where R has the abovementioned meaning can be introduced into the medium of the hydrolysis of the silicon alkoxide, whereby the oxide Boron and alcohol react in situ to form a boron alkoxide boron precursor, capable of leading to the incorporation of boron into the forming silica matrix.
- alumina Al 2 O 3 can be introduced together with an alcohol ROH, to form in situ an aluminum alkoxide precursor allowing the incorporation of aluminum into the silica matrix in formation.
- trivalent elemental oxide As a precursor of trivalent elemental oxide, it is also possible to introduce into the hydrolysis medium of silicon alkoxide an acid of the trivalent element, for example at least one compound having the following formula (I 1 ) :
- alkoxide-type trivalent element oxide precursor includes such an acid.
- the trivalent element used according to the invention is introduced into the silica-forming medium in a doping amount.
- silica generally remains the major constituent in the deposited silica layer.
- the oxide precursor of the trivalent element is most often introduced into the silica-forming medium with a trivalent element / silicon molar ratio of less than 1: 1 (100%), and most often less than at 1: 2, this ratio generally being greater than 1: 100 (1%).
- this ratio is most often advantageous for this ratio to be at least 1: 20 (5%), more preferably at least 1: 10 ( 10%), for example at least 1: 5 (20%).
- the molar ratio (trivalent element / silicon) in the silica-forming medium may advantageously be between 1% and 50%, typically between 5% and 40%, for example between 10% and 30%.
- the report molar (boron / silicon) in the silica forming medium is advantageously included in the above-mentioned terminal.
- this high selectivity of separation can be achieved with very small thicknesses of the silica layer, which allows to obtain at the same time very high permeances for gases such as hydrogen or helium.
- the process of the invention leads to permeation membranes making it possible to obtain highly efficient separations of gases such as He or H 2 at high temperature, with permeances that can reach values of the order of 10 -6 mol. .r ⁇ 2 .s "1 .Pa" 1.
- these benefits appear to be due at least in part to the introduction of the trivalent element in the silica network produced a decrease its degree of crosslinking and, consequently, a decrease in its rigidity, similar to that observed at low temperature using the alkyltrialkoxysilanes of the MTES type, but unlike the case of these alkyltrialkoxysilanes, the solution proposed in the context of the present invention does not imply the introduction of organic species within the silica network, which pyrolyze at high temperature by affecting the properties of the membrane, in particular by creating porosity.
- the method of the invention provides similar advantages to those obtained with the use of alkyltrialcoxysilanes type MTES, but allowing further implementation of the membrane at higher temperatures. It should be noted in this regard that the method of the invention is generally implemented in using tetraalkoxysilanes of the TEOS type, excluding silanes bearing non-reactive groups of alkyltrialkoxysilane type.
- boron is generally known as a vitrifying element, and it would therefore rather expected that its incorporation into the silica induces a decrease in the thermal stability of the ceramic microporous layer, detrimental to the separation of gases such that He or H 2 .
- the process of the invention can be carried out by implementing the currently known processes for depositing silica layers on porous supports using the sol-gel process, provided that it also introduces a precursor of an oxide of a trivalent element in the hydrolysis medium of the silicon alkoxide, so as to dope the silica formed by said trivalent element.
- the process of the invention comprises the following successive steps: (A) according to the sol-gel technique, a silica sol doped with said trivalent element is produced by hydrolyzing a silicon alkoxide (typically TEOS) in an aqueous medium, generally hydro-alcoholic, containing a doping amount of a precursor of an oxide of the trivalent element; (B) the soil thus prepared is deposited on a porous support; and
- a silicon alkoxide typically TEOS
- aqueous medium generally hydro-alcoholic, containing a doping amount of a precursor of an oxide of the trivalent element
- the deposited film is thermally treated, whereby it is converted into a microporous silica-based ceramic layer doped with the trivalent element.
- Step (A) for preparing the doped silica sol can be carried out under conditions known per se for the preparation of such sols.
- this This step is carried out by reacting the silicon alkoxide and the trivalent element oxide precursor in a hydroalcoholic medium at a pH suitable for the hydrolysis of these two compounds.
- This step (A) is carried out in an acid medium, typically at a pH of less than 2, preferably less than 1. This pH range is advantageously obtained by introducing into the medium a strong mineral acid such as nitric acid or hydrochloric acid.
- Step (A) is also advantageously carried out under conditions which initially allow the solubilization of the various reagents in the presence.
- step (A) is most often carried out in a hydro-alcoholic medium, preferably containing an alcohol selected from methanol, ethanol or propanol.
- the mass ratio water / alcohol is typically between 1: 5 and 5: 1, for example between 1: 3 and 3: 1.
- an alkoxide of the element trivalent, especially a boron alkoxide, as an oxide precursor it is particularly advantageous to use as alcohol an alcohol having substantially the same carbon number as the chains carried by the alkoxide, which makes it possible in particular to optimize the solubilization of the alkoxide.
- use is advantageously an alkoxide (I) of formula M (OR) 3 as defined above, and an alcohol of formula ROH, with identical R groups in the alcohol and the alkoxide (I).
- the concentration of silicon alkoxide is typically between 0.3 and 4 mol / L, this concentration being advantageously less than 3 mol / L, preferably less than 2 mol / L.
- this concentration is at least equal to 0.5 mol / L, which makes it possible in particular to facilitate the heat treatment step (C).
- step (A) is advantageously carried out by introducing boron oxide B 2 O 3 (typically in powder form) into a medium hydro-alcoholic (advantageously based on ethanol) containing a silicon alkoxide (generally a tetraalkoxysilane, for example TEOS) and brought to a pH below 2, typically less than 1.
- a silicon alkoxide generally a tetraalkoxysilane, for example TEOS
- B 2 O 3 introduced is converted in situ to boron alkoxide, which is then engaged with the silicon alkoxide in the hydrolysis and condensation reactions, whereby an acid boron-doped silica sol is obtained within its network.
- the reaction is preferably conducted at a temperature above 15 ° C, for example between 20 and 50 ° C., typically at a temperature below 40 ° C., which makes it possible to optimize the initial conversion of the boron oxide to alkoxide, so as to obtain an effective incorporation of boron in the silica network, rather than physical inclusions of B 2 O 3 in the structure of the silica.
- step (A) leads to the formation of a doped silica sol having a viscosity allowing deposition in the form of a film on a porous support in step (B) .
- This viscosity can be modulated by varying the duration and temperature of soil formation, gelation and viscosity increasing with aging time and with temperature.
- the technique used for the deposition of the film of step (B) depends on the nature of the porous support on which said film is to be deposited.
- the support may in particular be planar or tubular.
- the deposition of step (B) is generally carried out according to the so-called “spin coating” technique.
- the deposit of step (B) is rather carried out according to the so-called “slip casting” method.
- step (B) A very simple way to perform the deposition of step (B) is to immerse the porous support in the doped silica sol.
- this embodiment leads, surprisingly, to a particularly effective anchoring of the silica layer on the porous support.
- the immersion of the support in the soil makes it possible to substantially eliminate the presence of gas between the porous support and the silica layer being formed, which makes it possible to inhibit the phenomena of separation of the silica layer which are observed during the heat treatment of step (C) when the air remains present in the pores of the porous support.
- the porous support used in step (B) may be any porous support suitable for the preparation of gas separation membranes.
- the deposition of step (B) is carried out on a support comprising a porous alumina on the surface where the deposition is carried out.
- the support of step (B) comprises an alpha-alumina-based sub-layer (generally of a thickness of a few tens or hundreds of microns), on which a surface layer is deposited.
- gamma alumina generally a mesoporous layer having a thickness of the order of a few microns intended to receive the microporous layer based on doped silica deposited according to the invention.
- step (B) of the process (and, more generally, any step of depositing the silica sol doped on a porous support) can be optimized, for improve the cohesion of the silica layer doped on the porous support.
- the work carried out by the inventors shows that it is particularly advantageous to perform a pretreatment of the support prior to step (B), so as to increase its affinity for the deposited film.
- step (A-bis) it is particularly advantageous to conduct, prior to step (B), a step (A-bis) of pretreatment of the surface of the support to give it surface charges opposite to those of the doped silica of the soil used. in the film deposited in step (B).
- this step (A-bis) of pretreatment of the surface will typically be carried out by a base, typically ammonia (which will be removed during the treatment thermal step (C)).
- a basic sol it is preferable to treat the support with an acid, advantageously removable in step (C), typically hydrochloric or nitric acid.
- step (A-bis) is typically performed by immersion.
- step (A-bis) prior to step (B) can typically be carried out by impregnating the alumina-based support with an aqueous solution having a pH greater than the isoelectric point of the alumina. Since this isoelectric point is generally of the order of 9, the pH of the alumina-based surface treatment solution is advantageously greater than 10, for example between 10, typically of the order of 10.5.
- the process of the invention advantageously comprises, prior to the deposition of the film of step (B), a step (A-ter) of pre-impregnation of the porous support with the silica sol prepared by the step (A), followed by a surface rinsing of the support, and then a heat treatment of the thus rinsed support.
- step (A-ter) is advantageously carried out by totally immersing the porous support in the silica sol, which allows a particularly effective impregnation of the pores of the support.
- step (A-ter) By carrying out the above-mentioned step (A-ter), during the subsequent heat treatment of step (C), not only a doped silica-based surface layer, but a layer mechanically anchored in the pores is obtained. porous support, which prevents the phenomena of peeling of the silica layer.
- Pre-impregnation according to step (A-ter) is particularly effective with mesoporous supports, namely comprising pores with dimensions typically between 2 and 50 nm.
- the method of the invention comprises both the steps (A-bis) and (A-ter) above.
- step (A-bis) is preferably carried out before step (A-ter).
- the thermal pretreatment of the support is typically carried out at a temperature greater than 500 ° C., for example of the order of 600 ° C.
- Step (B) of the process of the invention is advantageously followed by a step of drying the film deposited on the support prior to step (C), which in particular makes it possible to further improve the cohesion between the deposited silica layer. and the support.
- This drying is generally carried out leaving the liquid film deposited on the support for 5 to 15 hours, typically 6 to 10 hours, at a temperature advantageously between 60 and 70 ° C., typically at a temperature of about 65.degree. ° C.
- step (C) of the process of the invention is a heat treatment which makes it possible to convert the film deposited in step (B) into a ceramic microporous layer based on doped silica.
- This heat treatment step can be carried out under the usual conditions used for the preparation of gas separation membranes. Typically, this heat treatment is carried out at a temperature of 300 to 600 ° C., generally above 400 ° C. (for example, between 500 and 600 ° C.) for a duration of a few hours (typically of the order of 2 hours).
- the heat treatment with low rise and fall in temperature, typically of the order of 0 , 1 to 5 0 C per minute, preferably less than 2 ° C per minute, for example between 0.5 and 1.5 ° C per minute, and typically of the order of 1 0 C per minute.
- a membrane adapted to the separation of gases comprising a microporous layer of silica doped with a trivalent element deposited on a porous support.
- Membranes of this type obtainable according to the process of the invention, constitute a particular object of the present invention.
- the process of the present invention gives access to original membranes, comprising a microporous layer of silica doped with boron, deposited on a microporous support.
- Such membranes have, to the knowledge of the inventors, never been described, and they constitute, as such, another object of the present invention.
- the microporous layer based on doped silica present in the membranes of the present invention is generally a thin layer having a thickness of between 50 and 500 nm, typically between 100 and 300 nm.
- the method of the invention also makes it possible to obtain microporous layers based on doped silica that are free from defects, even when the support used has a large size.
- the microporous layer based on doped silica present in the membranes of the invention is most often essentially (or exclusively) constituted by said doped silica, with the exception of other compounds or functional groups.
- the doped silica-based microporous layer of the membranes of the invention is generally free of organic groups of the type of those observed in the silica layers obtained by the sol-gel processes using alkyltrialkoxysilanes such as methyltriethoxysilane.
- the doped silica-based microporous layer present in the membranes of the present invention contains pores less than 1 nm in size.
- a doped silica sol where the silica is dispersed in the form of suspended objects (particles or particle aggregates) having hydrodynamic diameters less than 10 nm.
- the conditions to be used in step (A) to obtain such sols are illustrated in the examples below.
- the membranes of the invention advantageously comprise their silica layer doped on an alumina-based support of the type described above in the present description. Most often, this silica layer is a surface layer of the membrane. However, for certain particular applications, the silica layer deposited according to the process of the invention may be subsequently covered by another porous or quasi-dense layer (or several others), for example by a coating layer based on carbide silicon, allowing for example to perform a water separation.
- the membranes of the invention may contain several successive doped silica layers, typically obtained by repeating steps (A), (B) and (C).
- the membranes of the invention are particularly suitable for the separation of gases, and in particular for the separation of helium or hydrogen in gaseous mixtures comprising them, and in particular at higher temperatures. at 250 ° C., for example at temperatures of the order of 300 to 500 ° C., generally with transmembrane pressures of less than 8 bar.
- This specific application is another object of the present invention.
- the membranes of the invention comprise the microporous layer of doped silica deposited on a plane support.
- they are suitable for providing gas separation in the form of filters separating two cavities.
- they are advantageously in the form of plates or disks.
- the membranes of the invention comprise the microporous layer of doped silica deposited on the internal or external surface of a cylindrical support. These membranes are suitable for gas separation in a continuous mode.
- the membranes where the microporous layer of doped silica is deposited on the inner surface of the cylindrical support are generally used by circulating a gaseous mixture containing the gases to be extracted in the internal space of the cylinder, with a partial pressure of the gases to be extracted more important in this internal space than outside the cylinder. According to this mode, it is possible, for example, to purify a gaseous stream of helium or hydrogen containing impurities, helium or hydrogen being discharged from the cylinder and the impurities remaining trapped therein.
- the membranes comprising the microporous silica layer doped on the outer surface of the cylindrical support are rather intended to be used by circulating the gaseous mixture containing the gases to be extracted outside the cylinder and circulating in the internal space of the cylinder a stream of gases to be extracted with a reduced partial pressure relative to the outside.
- the gases to be extracted are entrained in the cylinder while the gases to be separated remain outside the cylinder.
- This mode is particularly suitable for extracting gases present in small amounts in a gas stream (hydrogen in hydrocarbon effluents for example).
- the membranes of the invention in particular those in which the doped silica-based microporous layer contains pores less than 1 nm in size, are particularly suitable for the separation of helium or hydrogen from a mixture comprising them. .
- membranes of this type are well suited to the removal of impurities in helium currents.
- the membranes of the invention find particularly useful application in the treatment of hot helium currents used in particular in the primary circuit of high-temperature nuclear reactors of new generation, so-called HTR.
- impurities such as CO, CO 2 or CHU. as well as Xe or Kr type fission products, which are present in the helium must be eliminated, insofar as they are a source of corrosion.
- the membranes of the invention make it possible to perform a such separation effectively, at working temperatures of helium in the reactor (between 300 and 500 0 C and under pressure).
- membranes in which the microporous layer of doped silica deposited on the surface of a cylindrical support, preferably on the inner surface, the membranes of the invention then making it possible to perform such a separation. in a continuous mode and in an efficient and quantitative manner, with permeances of up to values of the order of 10 -6 mol.m.sup.- 2 .sup.- 1 .Pa.sup.- 1 , and helium separation selectivities particularly high.
- the membranes of the invention find applications in many fields of use, given their multiple advantages.
- the membranes of the invention can be used to extract hydrogen hydrogen from gaseous mixtures containing it, such as effluents from petrochemical refineries, or to eliminate gaseous pollutants present in a stream of hydrogen, for example prior to its introduction into a synthesis reactor, or even into fuel cells (in particular of the PEM type) where they allow, among other things, to eliminate the CO type gases that can poison the catalysts.
- gaseous mixtures containing it such as effluents from petrochemical refineries
- gaseous pollutants present in a stream of hydrogen for example prior to its introduction into a synthesis reactor, or even into fuel cells (in particular of the PEM type) where they allow, among other things, to eliminate the CO type gases that can poison the catalysts.
- the membranes of the invention also lead to very good selectivities in the context of such hydrogen separation processes.
- the membranes of the invention can be used in many other fields where gas separation is required. inasmuch as they constitute very interesting improvements of the currently known membranes.
- the membranes of the invention are potentially usable for the separation of hydrogen and gases having a kinetic diameter greater than 0.30 mm, such as nitrogen, oxygen, carbonated gases (especially gases hydrocarbon), or even H2S.
- a membrane based on a microporous layer of silica doped with boron deposited on an alumina support was prepared under the following conditions:
- the alumina support used in this example is a carrier based on alumina marketed by PALL EXEKIA in the form of a hollow cylinder (internal diameter: 7 mm, outer diameter: 10 mm, length: 25 cm) comprising an inner layer based on mesoporous gamma-alumina (pore diameter: 5 nm) deposited on alpha alumina constituting the outside of the cylinder.
- This support was pretreated thermally at 600 ° C. (or 550 ° C.) according to the following profile: temperature rise at 1 ° C./min up to 600 ° C., hold for 2 hours at 600 ° C., temperature decrease to room temperature at 1 ° C / min.
- the support resulting from the preceding stage was completely immersed in the acidic soil (S) for 2 hours and then the support thus treated was rinsed with ethanol.
- the support was then dried by leaving it in an oven at 65 ° C for 8 hours.
- the support was heat-treated at 550 ° C. according to the following profile: rise in temperature at 1 ° C./min, hold at 550 ° C. for 2 hours, decrease in temperature at 1 ° C./min.
- the pretreated support from the previous steps was immersed completely in the soil (S) diluted with alcohol at 1/6 of its initial concentration for 2 hours.
- the support was then removed from the soil and allowed to dry in an oven at 65 ° C for 15 hours.
- the support covered by the film was heat-treated under the following conditions: - rise in temperature from 20 ° C. to 100 ° C., at a rate of 1 ° C. per minute;
- This membrane was tested by carrying out a separation of helium at 300 ° C. from a helium-based mixture containing 1% of CO 2 and 1% of CH 4 under the following conditions:
- a membrane based on a microporous double layer of silica doped with boron, deposited on an alumina support was prepared under the following conditions:
- the alumina support used in this example is a carrier based on alumina marketed by PALL EXEKIA in the form of a hollow cylinder (internal diameter: 7 mm, outer diameter: 10 mm, length: 25 cm) comprising an inner layer based on mesoporous gamma-alumina (pore diameter: 5 nm) deposited on alpha alumina constituting the outside of the cylinder.
- the support was first thermally pretreated to "open" the pores of the alumina. This treatment was carried out at 600 ° C. (or even 550 ° C.) according to the following profile: rise in temperature at 1 ° C./min up to 600 ° C., hold for 2 hours at 600 ° C., lowering temperature to temperature ambient at 1 ° C / min.
- the support was immersed in an aqueous ammonia solution of pH equal to 10.5, for 30 minutes, and then drained.
- the support was then immersed in silica / alumina sol (S Si / Al ) obtained by mixing:
- the support was heat-treated at 550 ° C. according to the following profile: rise in temperature at 1 ° C./min, hold at 550 ° C. for 2 hours, decrease in temperature at 1 ° C./min.
- the support was again immersed in an aqueous solution of ammonia with a pH of 10.5 for 30 minutes and then drained. The support was then completely immersed for 2 hours in the acidic soil (S) described in Example 1, and the support thus treated was rinsed with ethanol.
- the support was then dried by leaving it in an oven at 65 ° C for 8 to 12 hours. Following this drying, the support was heat-treated at 550 ° C. according to the following profile: rise in temperature at 1 ° C./min, hold at 550 ° C. for 2 hours, decrease in temperature at 1 ° C./min.
- the support was dried in an oven at 65 ° C for 8 to 12 hours in a vertical position, then subjected to heat treatment at 550 0 C (temperature rise at 1 ° C / min, holding at 550 ° C for 2 hours, lowering temperature to 1 ° C / min).
- the coated support thus obtained was immersed completely, firstly for 3 minutes in ethanol, then secondly in the soil (S), diluted with alcohol at 1/12 of its initial concentration, for 2 hours. Following this new immersion, the support was again dried in an oven at 65 ° C for 12 hours in a vertical position, then subjected to a heat treatment at 550 0 C (temperature rise at 1 ° C / min, maintenance at 550 0 C for 2 hours, lowering temperature to 1 ° C / min).
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Ceramic Engineering (AREA)
- Inorganic Chemistry (AREA)
- Materials Engineering (AREA)
- Structural Engineering (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Manufacturing & Machinery (AREA)
- Dispersion Chemistry (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Nanotechnology (AREA)
- Separation Using Semi-Permeable Membranes (AREA)
- Silicates, Zeolites, And Molecular Sieves (AREA)
- Hydrogen, Water And Hydrids (AREA)
- Silicon Compounds (AREA)
Abstract
The subject of the present invention is a method for producing a gas separation membrane, comprising the deposition of a film from a silica sol onto a porous support followed by heat treatment of the film thus deposited, in which the silica sol deposited is prepared by hydrolysing a silicon alkoxide in the presence of a doping amount of a precursor of an oxide of a trivalent element, especially boron or aluminium. The invention also relates to the membranes as obtained by this method, and also to their uses, especially for the separation of helium or hydrogen at high temperature, and in particular for removing impurities in helium streams.
Description
Membranes de séparation de gaz contenant une couche de silice microporeuse à base de silice dopée par un élément trivalent. Gas separation membranes containing a silica-based microporous silica layer doped with a trivalent element.
La présente invention a trait à des membranes céramiques, qui sont adaptées en particulier à la séparation de gaz par tamisage moléculaire. Plus spécifiquement, l'invention concerne un procédé qui permet de déposer sur un support poreux une couche microporeuse à base de silice amorphe substantiellement exempte de défauts et stable à haute température, donnant ainsi accès à des membranes capables d'assurer une séparation efficace de gaz tels que He ou H2 à des températures de l'ordre de 300 à 5000C.The present invention relates to ceramic membranes, which are particularly suitable for gas separation by molecular sieving. More specifically, the invention relates to a method for depositing on a porous support a microporous layer based on amorphous silica substantially free of defects and stable at high temperature, thus giving access to membranes capable of ensuring effective separation of gas such as He or H 2 at temperatures of the order of 300 to 500 ° C.
La séparation de gaz par des membranes est une technique largement utilisée par l'industrie chimique, qui a particulièrement été développée au cours des 25 dernières années. Selon la nature et la structure de la membrane utilisée (polymère, céramique, dense ou poreuse), différents mécanismes de transport et de séparation sont mis en jeu. Le tamisage moléculaire est une technique qui consiste à séparer des gaz présents en mélange, en utilisant une différence de rayon cinétique des molécules à séparer. A cet effet, on utilise une membrane microporeuse qui, sous l'effet d'une différence de concentration ou de pression partielle de part et d'autre de la membrane, laisse diffuser préférentiellement les molécules ayant le plus faible rayon cinétique et retient davantage les molécules de taille plus élevée. Dans ce cadre, la membrane est utilisée à titre de tamis moléculaire, mettant en œuvre un processus d'exclusion stérique ("pore size exclusion"), qui inhibe ou retarde la diffusion des molécules de taille importante, favorisant ainsi la diffusion des molécules de taille les plus faibles. En outre, dans certains cas, des phénomènes d'adsorption (en surface de la membrane et/ou dans ses pores) peuvent également contribuer à la séparation. Pour plus de détails concernant cette technique, on pourra notamment se reporter à "Fundamentals ofinorganic membrane science and technology", AJ. Burggraff et L. Cot, Elsevier, 1996. La technique de séparation de gaz transmembranaire précitée se révèle très avantageuse, notamment dans la mesure où elle est modulaire et utilisable selon un mode continu. Elle constitue en particulier une alternative très
intéressante aux autres procédés de séparation, tels que les procédés de cryogénie ou d'adsorption, par rapport auxquels elle s'avère plus simple à mettre en œuvre, et moins onéreuse. De ce fait, cette technique a, en pratique, de nombreux domaines d'application. Entre autres, elle est utilisée pour la séparation de O2 et de N2 à partir d'air, pour l'extraction de H2 et N2 dans des gaz de production de NH3, ou bien de H2 dans des effluents à base d'hydrocarbures tels que ceux issus des procédés de raffinage, ou bien encore pour éliminer CO2 ou NO dans divers effluents gazeux.Gas separation by membranes is a technique widely used by the chemical industry, which has been particularly developed over the last 25 years. Depending on the nature and structure of the membrane used (polymer, ceramic, dense or porous), different mechanisms of transport and separation are involved. Molecular sieving is a technique that consists of separating gases present in mixture, using a difference in kinetic radius of the molecules to be separated. For this purpose, a microporous membrane is used which, under the effect of a difference in concentration or of partial pressure on either side of the membrane, allows the molecules with the smallest kinetic radius to diffuse preferentially and retains more the molecules of higher size. In this context, the membrane is used as molecular sieve, implementing a steric exclusion process ("pore size exclusion"), which inhibits or delays the diffusion of large molecules, thus promoting the diffusion of size the weakest. In addition, in some cases, adsorption phenomena (on the surface of the membrane and / or in its pores) can also contribute to the separation. For more details on this technique, it will be possible to refer to "Fundamentals ofinorganic membrane science and technology", AJ. Burggraff and L. Cot, Elsevier, 1996. The aforementioned transmembrane gas separation technique is very advantageous, especially insofar as it is modular and can be used in a continuous mode. In particular, it constitutes a very interesting to other separation processes, such as cryogenics or adsorption processes, with respect to which it proves simpler to implement, and less expensive. As a result, this technique has, in practice, many fields of application. Among other things, it is used for the separation of O 2 and N 2 from air, for the extraction of H 2 and N 2 in NH 3 production gases, or of H 2 in effluents with hydrocarbon base such as those resulting from refining processes, or else to remove CO 2 or NO in various gaseous effluents.
L'efficacité d'une séparation de gaz par une membrane est limitée par deux paramètres, à savoir :The efficiency of gas separation by a membrane is limited by two parameters, namely:
(i) la capacité que présente la membrane utilisée à laisser diffuser les molécules de faible taille ; et(i) the capacity of the membrane used to let small molecules spread; and
(ii) l'aptitude de la membrane à bloquer les molécules de taille plus importante. Le premier paramètre (i) est exprimé par la "perméance" de la membrane, à savoir la quantité de gaz que laisse diffuser la membrane par unité de surface et de temps en fonction de la pression appliquée (exprimée en mol.m"2.s"1.Pa"1).(ii) the ability of the membrane to block larger molecules. The first parameter (i) is expressed by the "permeance" of the membrane, namely the amount of gas that the membrane allows to diffuse per unit area and time as a function of the applied pressure (expressed in mol.m- 2 . s "1 .Pa " 1 ).
Le second paramètre (ii) est quant à lui reflété par la "sélectivité" de la membrane, qui est calculée par le ratio (en mole) de la quantité de molécules de faible taille (dont la diffusion est recherchée) sur la quantité de molécules de taille plus importante (censées être retenues) qui sont contenues dans le mélange gazeux que laisse diffuser la membrane.The second parameter (ii) is in turn reflected by the "selectivity" of the membrane, which is calculated by the ratio (in moles) of the quantity of small molecules (whose diffusion is sought) on the quantity of molecules. larger size (supposed to be retained) that are contained in the gas mixture that allows the membrane to diffuse.
Des membranes ayant une efficacité de séparation élevée en termes de perméance et de sélectivité sont d'autant plus difficiles à obtenir que le diamètre hydrodynamique des gaz à séparer est faible. Ainsi, la technique de séparation de gaz se révèle tout particulièrement délicate lorsqu'on souhaite effectuer une séparation d'hélium (diamètre cinétique inférieur à 0,30 nm) ou de gaz ayant des diamètres cinétiques similaires, tels que H2 ou H2O, ou leurs équivalents deutérés ou tritiés. Dans ce cadre, il est nécessaire d'utiliser des membranes comprenant une couche de séparation ayant des pores de dimensions extrêmement réduites, en
général inférieures à 1 nm, et ce en nombre suffisant pour permettre d'obtenir une bonne perméation. On connaît actuellement des membranes de ce type, comprenant des couches ayant un diamètre de pores inférieur à 1 nm.Membranes having a high separation efficiency in terms of permeance and selectivity are all the more difficult to obtain as the hydrodynamic diameter of the gases to be separated is small. Thus, the gas separation technique is particularly delicate when it is desired to carry out a separation of helium (kinetic diameter less than 0.30 nm) or of gas having similar kinetic diameters, such as H 2 or H 2 O , or their deuterated or tritiated equivalents. In this context, it is necessary to use membranes comprising a separation layer having pores of extremely small dimensions, general less than 1 nm, and this in sufficient number to allow to obtain good permeation. Membranes of this type are currently known, including layers having a pore diameter of less than 1 nm.
Comme membranes de ce type, on peut notamment citer des membranes comprenant une couche dense ou microporeuses, telles qu'une couche microporeuse à base de silice (couche généralement désignée par MMS, pour l'anglais "molecular sieve silica").As membranes of this type, there may be mentioned membranes comprising a dense or microporous layer, such as a microporous layer based on silica (generally called MMS layer for the English "molecular sieve silica").
Ces membranes incluant une couche microporeuse à base de silice sont généralement obtenues en déposant un film d'un sol de silice sur un support poreux (par exemple un support à base d'alumine), puis en traitant thermiquement le film obtenu pour le convertir en une couche céramique de silice microporeuse. Le sol de silice utilisé dans ce cadre est généralement obtenu selon la technique dite "sol-gel", à savoir en hydrolysant un alcoxyde de silicium, typiquement un tétraalcoxysilane tel que le TEOS (tétraéthoxysilane, de formule Si(OEt)4), ce qui conduit à Ia formation d'espèces silanols qui polymérisent pour former des clusters de silice, ces clusters se condensant ensuite pour former un sol de viscosité importante, de type gel. Un tel procédé de dépôt de couche mince de silice à partir d'un précurseur de silice de type alcoxyde de silicium a largement été décrite dans la littérature, notamment dans l'ouvrage précité "Fundamentals of inorganic membrane science and technology", Elsevier, 1996, au chapitre 8 (p. 259).These membranes including a silica-based microporous layer are generally obtained by depositing a film of a silica sol on a porous support (for example an alumina-based support), then thermally treating the resulting film to convert it to a ceramic layer of microporous silica. The silica sol used in this context is generally obtained according to the so-called "sol-gel" technique, namely by hydrolyzing a silicon alkoxide, typically a tetraalkoxysilane such as TEOS (tetraethoxysilane, of formula Si (OEt) 4 ). which leads to the formation of silanols species which polymerize to form silica clusters, these clusters then condensing to form a sol of high viscosity, gel type. Such a silica thin film deposition process from a silicon alkoxide silica precursor has been widely described in the literature, especially in the aforementioned work "Fundamentals of inorganic membrane science and technology", Elsevier, 1996 in chapter 8 (page 259).
Un problème majeur rencontré avec les membranes incluant des couches microporeuses à base de silice du type précité est leur propension à la présence de défauts, qui affectent la sélectivité de la membrane. Ces défauts sont principalement liés à la rigidité du réseau de silice, qui est source de formation de fissures lorsque la couche est soumise à des contraintes (ce qui est tout particulièrement le cas avec des membranes de taille importante nécessaires pour des séparations de gaz à l'échelle industrielle) et/ou lorsqu'elle est déposée sur un support présentant des irrégularités de surface (ce qui est quasiment toujours le cas). Les fissures ainsi formées nuisent considérablement à Ia sélectivité de la membrane, dans la mesure où, plutôt qu'à travers les pores, les gaz diffusent préférentiellement au niveau des fissures, qui sont de nature à
laisser diffuser des espèces de diamètre cinétique plus important que les espèces à séparer. Pour obtenir des sélectivités élevées, il s'avère nécessaire de s'affranchir au maximum du phénomène de fissuration, et de façon plus générale de la formation de défauts. Une solution qui a été proposée pour limiter les phénomènes de fissuration dans des couches microporeuses de silice obtenues selon la voie sol-gel consiste à remplacer tout ou partie des tétraalcoxysilanes utilisés comme précurseurs de la silice par des alcoxysilanes porteurs de moins de 4 groupements réactifs de type alcoxy. Dans ce cadre, il a typiquement été proposé de remplacer tout ou partie du TEOS par des alkyltrialcoxysilanes tels que le méthyltriéthoxysilane (MTES, de formule Si(CH3)(OEt)3). La mise en œuvre de ces silanes porteurs de groupes non réactifs induit un abaissement du degré de réticulation du réseau de la silice obtenue par rapport à l'emploi de précurseurs de type TEOS, dans la mesure où les groupes non réactifs (de type alkyle) ne participent pas à la polymérisation entre les espèces silanols. Ainsi, on obtient une diminution de la rigidité de la couche de silice déposée, et par conséquent une réduction de sa tendance à la fissuration. Une telle solution a notamment été décrite dans SoI-GeI Sci. Technol., 3, 47 (1994) ou bien dans Thin Solid Films, 462-463 (2004). Cela étant, cette mise en œuvre d'alkyltrialcoxysilanes de type MTES ne s'avère intéressante que pour des séparations de gaz à basse température. Au contraire, elle se révèle en général insatisfaisante lorsque la couche microporeuse doit être utilisée à haute température, en particulier à des températures supérieures à 2000C, et plus encore à des températures supérieures à 2500C. En effet, les couches microporeuse de silice qui sont obtenues à partir d'alkyltrialcoxysilanes de type MTES comportent spécifiquement des groupes alkyles au sein de leur structure. Sous l'effet d'une augmentation de température dans les gammes précitées, ces groupes s'oxydent et sont extraits avec départ de CO2, ce qui induit l'apparition d'une porosité supplémentaire dans la couche, généralement associée à une fragilisation de cette couche, susceptible d'induire des fissurations. Ces différents phénomènes sont préjudiciables à la sélectivité de la séparation de gaz. En particulier, les
membranes à base d'une couche obtenue à partir de MTES ne sont en général pas adaptées à une séparation efficace d'hélium ou de H2 à des températures de l'ordre de 3000C à 5000C, en particulier sous pression.A major problem encountered with membranes including silica-based microporous layers of the aforementioned type is their propensity for the presence of defects, which affect the selectivity of the membrane. These defects are mainly related to the rigidity of the silica network, which is a source of crack formation when the layer is subjected to stresses (which is particularly the case with membranes of large size necessary for gas separations at high temperatures. industrial scale) and / or when it is deposited on a support having surface irregularities (which is almost always the case). The cracks thus formed considerably affect the selectivity of the membrane, insofar as, rather than through the pores, the gases preferentially diffuse at the level of the cracks, which are of a nature to let species of greater kinetic diameter spread than the species to be separated. To obtain high selectivities, it is necessary to overcome as much as possible the phenomenon of cracking, and more generally of the formation of defects. A solution that has been proposed to limit the phenomena of cracking in microporous layers of silica obtained by the sol-gel route consists in replacing all or part of the tetraalkoxysilanes used as precursors of the silica with alkoxysilanes carrying less than 4 reactive groups of silica. alkoxy type. In this context, it has typically been proposed to replace all or part of the TEOS by alkyltrialkoxysilanes such as methyltriethoxysilane (MTES, of formula Si (CH 3 ) (OEt) 3 ). The use of these silanes bearing nonreactive groups induces a lowering of the degree of crosslinking of the network of the silica obtained relative to the use of precursors of the TEOS type, insofar as the non-reactive groups (of alkyl type) do not participate in the polymerization between the silanol species. Thus, a decrease in the rigidity of the deposited silica layer is obtained, and consequently a reduction in its tendency to crack. Such a solution has in particular been described in SoI-GeI Sci. Technol., 3, 47 (1994) or in Thin Solid Films, 462-463 (2004). However, this implementation of alkyltrialkoxysilanes type MTES is only interesting for low temperature gas separations. On the contrary, it is generally unsatisfactory when the microporous layer is to be used at high temperature, in particular at temperatures above 200 ° C., and more particularly at temperatures above 250 ° C. In fact, the microporous layers of silica which are obtained from alkyltrialkoxysilanes of type MTES specifically contain alkyl groups within their structure. Under the effect of an increase in temperature in the abovementioned ranges, these groups oxidize and are extracted with CO 2 starting, which induces the appearance of additional porosity in the layer, generally associated with embrittlement. this layer, likely to induce cracking. These different phenomena are detrimental to the selectivity of the gas separation. In particular, membranes based on a layer obtained from MTES are generally not suitable for effective separation of helium or H 2 at temperatures of the order of 300 0 C to 500 0 C, in particular under pressure.
Une solution permettant d'obtenir des couches microporeuses de silice faiblement réticulée, permettant d'accéder à des membranes adaptées à une séparation efficace d'hydrogène ou d'hélium avec une bonne sélectivité, a été décrite dans la demande US 2004/00380044. Dans ce document, il est proposé un procédé de synthèse de silice conduit selon un processus sol-gel catalysé en deux étapes, où les conditions de dilution sont maîtrisées pour éviter l'apparition de fissuration lors d'un traitement de la couche en température. Ce procédé s'avère toutefois lourd à mettre en œuvre, dans la mesure où il implique un contrôle fin d'un grand nombre de paramètres de préparation de la couche de silice.A solution making it possible to obtain microporous layers of weakly crosslinked silica, making it possible to access membranes adapted to efficient separation of hydrogen or helium with good selectivity, has been described in application US 2004/00380044. In this document, it is proposed a silica synthesis process conducted according to a two-stage catalyzed sol-gel process, where the dilution conditions are controlled to prevent the occurrence of cracking during treatment of the layer temperature. However, this process is difficult to implement, insofar as it involves a fine control of a large number of preparation parameters of the silica layer.
Un but de la présente invention est de fournir un nouveau procédé permettant d'accéder à des membranes de séparation de gaz capables d'assurer une séparation d'hélium ou d'hydrogène à une température supérieure à 2000C, en particulier à des températures de l'ordre de 300 à 5000C, et ce avec une perméance et une sélectivité de préférence au moins aussi bonne, et avantageusement supérieures à celles des membranes de séparation actuellement connues. Dans ce cadre, l'invention vise en particulier à fournir des membranes ayant de telles propriétés de perméance et de sélectivité sans avoir à mettre en œuvre le procédé spécifique décrit dans US 2004/00380044.An object of the present invention is to provide a novel method for accessing gas separation membranes capable of separating helium or hydrogen at a temperature greater than 200 ° C., in particular at temperatures of the order of 300 to 500 0 C, and with a permeance and a selectivity preferably at least as good, and advantageously greater than those currently known separation membranes. In this context, the invention aims in particular to provide membranes having such properties of permeance and selectivity without having to implement the specific method described in US 2004/00380044.
A cet effet, la présente invention a pour objet un procédé de préparation d'une membrane de séparation de gaz, comprenant le dépôt d'un film d'un sol de silice sur un support poreux, puis le traitement thermique du film ainsi déposé, caractérisé en ce que le sol de silice qui est déposé sous forme de film sur le support poreux est préparé en hydrolysant un alcoxyde de silicium en présence d'une quantité dopante d'un précurseur d'un oxyde d'un élément trivalent, ce précurseur étant par exemple un alcoxyde ou bien encore un acide de l'élément trivalent.
Par "élément trivalent", on entend, au sens de la présente description, ici un élément dont les atomes sont capables de s'insérer dans le réseau de la silice avec un degré de réticulation au plus égal à 3. L'élément trivalent utilisé selon la présente invention est le bore (B). Le bore est généralement utilisé à titre d'unique élément trivalent. Toutefois, le bore peut alternativement être utilisé en mélange avec d'autres éléments trivalents, par exemple l'aluminium.For this purpose, the subject of the present invention is a process for preparing a gas separation membrane, comprising the deposition of a film of a silica sol on a porous support, and then the heat treatment of the film thus deposited, characterized in that the silica sol which is deposited as a film on the porous support is prepared by hydrolyzing a silicon alkoxide in the presence of a doping amount of a precursor of an oxide of a trivalent element, this precursor being for example an alkoxide or an acid of the trivalent element. By "trivalent element" is meant, in the sense of the present description, here an element whose atoms are capable of being inserted into the silica network with a degree of crosslinking at most equal to 3. The trivalent element used according to the present invention is boron (B). Boron is generally used as the only trivalent element. However, the boron may alternatively be used in admixture with other trivalent elements, for example aluminum.
L'expression "précurseur d'oxyde d'un élément trivalent" désigne, au sens de la présente description, un composé qui est capable de former un oxyde à base de l'élément trivalent dans les conditions d'hydrolyse de l'alcoxyde de silicium, ce qui, dans le procédé de l'invention, permet d'incorporer l'élément trivalent dans le réseau de la silice au cours de sa formation.The expression "oxide precursor of a trivalent element" denotes, within the meaning of the present description, a compound which is capable of forming an oxide based on the trivalent element under the conditions of hydrolysis of the alkoxide of silicon, which, in the method of the invention, allows to incorporate the trivalent element in the silica network during its formation.
Le plus souvent, le précurseur utilisé à cet effet est un alcoxyde de l'élément trivalent.Most often, the precursor used for this purpose is an alkoxide of the trivalent element.
Ainsi, selon son mode le plus général, le procédé de la présente invention consiste, à préparer la membrane selon une technique sol-gel usuelle, mais en effectuant spécifiquement l'hydrolyse de l'alcoxyde de silicium avec la présence additionnelle d'un précurseur d'un oxyde d'un élément trivalent.Thus, according to its most general mode, the process of the present invention consists in preparing the membrane according to a conventional sol-gel technique, but by specifically performing the hydrolysis of the silicon alkoxide with the additional presence of a precursor an oxide of a trivalent element.
L'alcoxyde d'élément trivalent utilisé est généralement introduit dans le milieu d'hydrolyse de l'alcoxyde de silicium sous la forme d'au moins un composé répondant à la formule (I) suivante :The trivalent element alkoxide used is generally introduced into the hydrolysis medium of the silicon alkoxide in the form of at least one compound corresponding to the following formula (I):
M(OR)3 formule (I) dans laquelle :M (OR) 3 formula (I) in which:
- M désigne le bore (B) ; etM denotes boron (B); and
- les 3 groupements R sont identiques ou différents (généralement identiques), et chacun représente une chaîne hydrocarbonée comprenant de 1 à 8 atomes de carbone, de préférence un groupe alkyle, contenant de préférence de 2 à 4 atomes de carbone.the 3 R groups are identical or different (generally identical), and each represents a hydrocarbon chain comprising from 1 to 8 carbon atoms, preferably an alkyl group, preferably containing from 2 to 4 carbon atoms.
Selon une variante particulière, l'alcoxyde d'élément trivalent utilisé peut être formé in situ dans le milieu de l'hydrolyse de l'alcoxyde de silicium. Dans ce
cadre, on peut typiquement introduire de l'oxyde de bore B2O3 et un alcool de formule ROH, où R a la signification précitée, dans le milieu de l'hydrolyse de l'alcoxyde de silicium, ce par quoi l'oxyde de bore et l'alcool réagissent in situ pour former un précurseur d'oxyde de bore, de type alcoxyde de bore, capable de conduire à l'incorporation de bore dans la matrice de silice en formation. De la même façon, on peut introduire de l'alumine AI2O3 conjointement à un alcool ROH, pour former in situ un précurseur de type alcoxyde d'aluminium permettant l'incorporation d'aluminium dans la matrice de silice en formation.According to a particular variant, the trivalent element alkoxide used can be formed in situ in the medium of the hydrolysis of the silicon alkoxide. In this In the framework, boron oxide B 2 O 3 and an alcohol of formula ROH, where R has the abovementioned meaning, can be introduced into the medium of the hydrolysis of the silicon alkoxide, whereby the oxide Boron and alcohol react in situ to form a boron alkoxide boron precursor, capable of leading to the incorporation of boron into the forming silica matrix. In the same way, alumina Al 2 O 3 can be introduced together with an alcohol ROH, to form in situ an aluminum alkoxide precursor allowing the incorporation of aluminum into the silica matrix in formation.
A titre de précurseur d'oxyde d'élément trivalent, on peut également introduire dans le milieu d'hydrolyse de l'alcoxyde de silicium un acide de l'élément trivalent, par exemple au moins un composé ayant la formule (I1) suivante :As a precursor of trivalent elemental oxide, it is also possible to introduce into the hydrolysis medium of silicon alkoxide an acid of the trivalent element, for example at least one compound having the following formula (I 1 ) :
M(OH)3 (I1)M (OH) 3 (I 1 )
où M désigne le bore (B).where M is boron (B).
Au sens où il est utilisé dans la présente description, le terme "précurseur d'oxyde d'élément trivalent de type alcoxyde" englobe un tel acide.As used herein, the term "alkoxide-type trivalent element oxide precursor" includes such an acid.
Quel que soit son mode d'introduction, l'élément trivalent utilisé selon l'invention est introduit dans le milieu de formation de la silice en une quantité dopante. Ainsi la silice reste en général le constituant majoritaire dans la couche de silice déposée. Dans ce cadre, le précurseur d'oxyde de l'élément trivalent est le plus souvent introduit dans le milieu de formation de la silice avec un rapport molaire élément trivalent / silicium inférieur à 1 : 1 (100%), et le plus souvent inférieur à 1 : 2, ce rapport étant en général supérieur à 1 : 100 (1%). Notamment pour obtenir une diminution de la tendance à la fissuration la plus marquée possible, il s'avère le plus souvent avantageux que ce ratio soit d'au moins 1 : 20 (5%), plus préférentiellement d'au moins 1 : 10 (10%), par exemple d'au moins 1 : 5 (20%). Ainsi, le rapport molaire (élément trivalent / silicium) dans le milieu de formation de la silice peut avantageusement être compris entre 1 % et 50 %, typiquement entre 5 % et 40 %, par exemple entre 10 % et 30 %. Le rapport
molaire (bore/silicium) dans le milieu de formation de la silice est avantageusement compris dans la borne précitée.Whatever its mode of introduction, the trivalent element used according to the invention is introduced into the silica-forming medium in a doping amount. Thus, silica generally remains the major constituent in the deposited silica layer. In this context, the oxide precursor of the trivalent element is most often introduced into the silica-forming medium with a trivalent element / silicon molar ratio of less than 1: 1 (100%), and most often less than at 1: 2, this ratio generally being greater than 1: 100 (1%). In particular, to obtain a reduction in the tendency to cracking as much as possible, it is most often advantageous for this ratio to be at least 1: 20 (5%), more preferably at least 1: 10 ( 10%), for example at least 1: 5 (20%). Thus, the molar ratio (trivalent element / silicon) in the silica-forming medium may advantageously be between 1% and 50%, typically between 5% and 40%, for example between 10% and 30%. The report molar (boron / silicon) in the silica forming medium is advantageously included in the above-mentioned terminal.
Les inventeurs ont maintenant mis en évidence que, lorsqu'on dépose sur un support poreux un sol de silice préparé selon le procédé sol-gel en présence d'un précurseur d'oxyde d'un élément trivalent de type alcoxyde du type précité, on obtient une membrane où la présence de fissures se trouve substantiellement inhibée dans la couche microporeuse de silice. On obtient ainsi une membrane permettant des séparations de He ou de H2 à partir de mélange gazeux les contenant avec des sélectivités relativement élevées. De plus, il s'avère que la haute sélectivité ainsi obtenue reste importante haute température, notamment à des températures supérieures à 2500C, et même à des températures de l'ordre de 300 à 500° C. En outre, de façon surprenante, cette haute sélectivité de séparation peut être atteinte avec de très faibles épaisseurs de la couche de silice, ce qui permet d'obtenir dans le même temps des perméances très élevées pour des gaz tels que l'hydrogène ou l'hélium. Ainsi, le procédé de l'invention conduit à des membranes de perméation permettant d'obtenir des séparations très efficaces de gaz tels que He ou de H2 à haute température, avec des perméances pouvant atteindre des valeurs de l'ordre de 10"6 mol.rτï2.s"1.Pa"1. Sans vouloir être lié à une théorie particulière, ces avantages semblent dus au moins en partie au fait que l'introduction de l'élément trivalent dans le réseau de la silice induit une diminution de son degré de réticulation et, par conséquent, une diminution de sa rigidité, analogue à celle observée à basse température en utilisant les alkyltrialcoxysilanes de type MTES. Toutefois, contrairement au cas de ces alkyltrialcoxysilanes, la solution proposée dans le cadre de la présente invention n'implique pas l'introduction d'espèces organiques au sein du réseau de silice, qui se pyrolysent à haute température en affectant les propriétés de la membrane, notamment par création de porosité. Ainsi, le procédé de l'invention permet d'obtenir des avantages similaires à ceux obtenus avec l'emploi des alkyltrialcoxysilanes de type MTES, mais en permettant en outre une mise en œuvre de la membrane à des températures plus élevées. A noter à ce sujet que le procédé de l'invention est généralement mis en œuvre en
utilisant des tétraalcoxysilanes de type TEOS, à l'exclusion de silanes porteurs de groupements non réactifs de type alkyltrialcoxysilane.The inventors have now demonstrated that, when a silica sol prepared by the sol-gel process is deposited on a porous support in the presence of an alkaline-type trivalent element precursor of the aforementioned type, obtains a membrane in which the presence of cracks is substantially inhibited in the microporous layer of silica. A membrane is thus obtained allowing separations of He or H 2 from gaseous mixtures containing them with relatively high selectivities. In addition, it turns out that the high selectivity thus obtained remains significant high temperature, especially at temperatures above 250 0 C, and even at temperatures of the order of 300 to 500 ° C. In addition, surprisingly this high selectivity of separation can be achieved with very small thicknesses of the silica layer, which allows to obtain at the same time very high permeances for gases such as hydrogen or helium. Thus, the process of the invention leads to permeation membranes making it possible to obtain highly efficient separations of gases such as He or H 2 at high temperature, with permeances that can reach values of the order of 10 -6 mol. .rτï 2 .s "1 .Pa" 1. Without being bound by theory, these benefits appear to be due at least in part to the introduction of the trivalent element in the silica network produced a decrease its degree of crosslinking and, consequently, a decrease in its rigidity, similar to that observed at low temperature using the alkyltrialkoxysilanes of the MTES type, but unlike the case of these alkyltrialkoxysilanes, the solution proposed in the context of the present invention does not imply the introduction of organic species within the silica network, which pyrolyze at high temperature by affecting the properties of the membrane, in particular by creating porosity. insi, the method of the invention provides similar advantages to those obtained with the use of alkyltrialcoxysilanes type MTES, but allowing further implementation of the membrane at higher temperatures. It should be noted in this regard that the method of the invention is generally implemented in using tetraalkoxysilanes of the TEOS type, excluding silanes bearing non-reactive groups of alkyltrialkoxysilane type.
Cette possibilité d'utilisation à haute température est tout particulièrement surprenante dans le cas de l'utilisation du bore à titre d'élément dopant trivalent. En effet, le bore est généralement connu comme un élément vitrifiant, et on se serait de ce fait plutôt attendu à ce que son incorporation dans la silice induise une diminution de la stabilité thermique de la couche microporeuse céramique, nuisible à la séparation de gaz tels que He ou H2.This possibility of use at high temperature is particularly surprising in the case of the use of boron as a trivalent doping element. Indeed, boron is generally known as a vitrifying element, and it would therefore rather expected that its incorporation into the silica induces a decrease in the thermal stability of the ceramic microporous layer, detrimental to the separation of gases such that He or H 2 .
En outre, les inventeurs ont mis en évidence que le procédé de l'invention permet d'obtenir ces améliorations de la membrane de façon très simple et reproductible.In addition, the inventors have demonstrated that the process of the invention makes it possible to obtain these improvements of the membrane in a very simple and reproducible manner.
De façon très générale, le procédé de l'invention peut être conduit en mettant en oeuvre les procédés actuellement connus de dépôt de couches de silice sur des supports poreux utilisant le procédé sol-gel, sous réserve d'introduire en outre un précurseur d'un oxyde d'un élément trivalent dans le milieu d'hydrolyse de l'alcoxyde de silicium, de façon à doper la silice formée par ledit élément trivalent.In a very general manner, the process of the invention can be carried out by implementing the currently known processes for depositing silica layers on porous supports using the sol-gel process, provided that it also introduces a precursor of an oxide of a trivalent element in the hydrolysis medium of the silicon alkoxide, so as to dope the silica formed by said trivalent element.
Selon un mode de réalisation particulièrement intéressant, le procédé de l'invention comporte les étapes successives suivantes : (A) selon la technique sol-gel, on réalise un sol de silice dopée par ledit élément trivalent, en hydrolysant un alcoxyde de silicium (typiquement du TEOS) au sein d'un milieu aqueux, généralement hydro-alcoolique, contenant une quantité dopante d'un précurseur d'un oxyde de l'élément trivalent ; (B) on dépose le sol ainsi préparé sur un support poreux ; etAccording to a particularly advantageous embodiment, the process of the invention comprises the following successive steps: (A) according to the sol-gel technique, a silica sol doped with said trivalent element is produced by hydrolyzing a silicon alkoxide (typically TEOS) in an aqueous medium, generally hydro-alcoholic, containing a doping amount of a precursor of an oxide of the trivalent element; (B) the soil thus prepared is deposited on a porous support; and
(C) on traite thermiquement le film ainsi déposé, ce par quoi on le convertit en une couche microporeuse céramique à base de silice dopée par l'élément trivalent.(C) the deposited film is thermally treated, whereby it is converted into a microporous silica-based ceramic layer doped with the trivalent element.
L'étape (A) de préparation du sol de silice dopée peut être conduite dans des conditions connues en soi pour la préparation de tels sols. En général, cette
étape est conduite en faisant réagir l'alcoxyde de silicium et le précurseur d'oxyde d'élément trivalent en milieu hydro-alcoolique à un pH adapté à l'hydrolyse de ces deux composés. Cette étape (A) est conduite en milieu acide, typiquement à un pH inférieur à 2, de préférence inférieur à 1. Cette gamme de pH est avantageusement obtenue en introduisant dans le milieu un acide minéral fort tel que l'acide nitrique ou l'acide chlorhydrique.Step (A) for preparing the doped silica sol can be carried out under conditions known per se for the preparation of such sols. In general, this This step is carried out by reacting the silicon alkoxide and the trivalent element oxide precursor in a hydroalcoholic medium at a pH suitable for the hydrolysis of these two compounds. This step (A) is carried out in an acid medium, typically at a pH of less than 2, preferably less than 1. This pH range is advantageously obtained by introducing into the medium a strong mineral acid such as nitric acid or hydrochloric acid.
L'étape (A) est par ailleurs avantageusement conduite dans des conditions permettant initialement la solubilisation des différents réactifs en présence. Notamment à cet effet, l'étape (A) est le plus souvent conduite dans un milieu hydro-alcoolique, contenant de préférence un alcool choisi parmi le méthanol, l'éthanol ou le propanol. Dans ce milieu hydro-alcoolique, le rapport massique eau/alcool est typiquement compris entre 1 : 5 et 5 : 1 , par exemple entre 1 : 3 et 3 : 1. Dans ce cadre, lorsqu'on utilise un alcoxyde de l'élément trivalent, notamment un alcoxyde de bore, à titre de précurseur d'oxyde, il est tout particulièrement avantageux d'employer comme alcool un alcool ayant sensiblement le même nombre de carbone que les chaînes portées par l'alcoxyde, ce qui permet notamment d'optimiser la solubilisation de l'alcoxyde. Dans ce cadre, on utilise avantageusement un alcoxyde (I) de formule M(OR)3 telle que définie précédemment, et un alcool de formule ROH, avec des groupements R identiques dans l'alcool et l'alcoxyde (I).Step (A) is also advantageously carried out under conditions which initially allow the solubilization of the various reagents in the presence. In particular for this purpose, step (A) is most often carried out in a hydro-alcoholic medium, preferably containing an alcohol selected from methanol, ethanol or propanol. In this hydroalcoholic medium, the mass ratio water / alcohol is typically between 1: 5 and 5: 1, for example between 1: 3 and 3: 1. In this context, when using an alkoxide of the element trivalent, especially a boron alkoxide, as an oxide precursor, it is particularly advantageous to use as alcohol an alcohol having substantially the same carbon number as the chains carried by the alkoxide, which makes it possible in particular to optimize the solubilization of the alkoxide. In this context, use is advantageously an alkoxide (I) of formula M (OR) 3 as defined above, and an alcohol of formula ROH, with identical R groups in the alcohol and the alkoxide (I).
Par ailleurs, dans le milieu de l'étape (A), la concentration en alcoxyde de silicium (TEOS par exemple) est typiquement comprise entre 0,3 et 4 mol/L, cette concentration étant avantageusement inférieure à 3 mol/L, de préférence inférieure à 2 mol/L. Avantageusement, cette concentration est au moins égale à 0,5 mol/L, ce qui permet en particulier de faciliter l'étape de traitement thermique (C). Des concentrations inférieures à 1 ,5 mol/L, par exemple entre 0,5 et 1 mol/L, conduisent en général à une structure optimale de la couche microporeuse à base de silice formée dans l'étape (C).Moreover, in the medium of step (A), the concentration of silicon alkoxide (TEOS for example) is typically between 0.3 and 4 mol / L, this concentration being advantageously less than 3 mol / L, preferably less than 2 mol / L. Advantageously, this concentration is at least equal to 0.5 mol / L, which makes it possible in particular to facilitate the heat treatment step (C). Concentrations of less than 1.5 mol / l, for example between 0.5 and 1 mol / l, generally lead to an optimal structure of the silica-based microporous layer formed in step (C).
Dans le cas particulier de la mise en œuvre de bore à titre d'élément dopant trivalent, l'étape (A) est avantageusement conduite en introduisant de l'oxyde de bore B2O3 (typiquement sous forme pulvérulente) dans un milieu
hydro-alcoolique (avantageusement à base d'éthanol) contenant un alcoxyde de silicium (en général un tétraalcoxysilane, par exemple du TEOS) et porté à un pH inférieur à 2, typiquement inférieur à 1. Selon cette variante spécifique, le B2O3 introduit est converti in situ en alcoxyde de bore, qui est ensuite engagé avec l'alcoxyde de silicium dans les réactions d'hydrolyse et de condensation, ce par quoi on obtient un sol acide de silice dopée par du bore au sein de son réseau. Dans ce cadre, la réaction est de préférence conduite à une température supérieure à 15°C, par exemple entre 20 et 500C, typiquement à une température inférieure à 4O0C, ce qui permet d'optimiser la conversion initiale de l'oxyde de bore en alcoxyde, de façon à obtenir une incorporation effective de bore dans le réseau de la silice, plutôt que des inclusions physique de B2O3 dans la structure de la silice.In the particular case of the use of boron as a trivalent doping element, step (A) is advantageously carried out by introducing boron oxide B 2 O 3 (typically in powder form) into a medium hydro-alcoholic (advantageously based on ethanol) containing a silicon alkoxide (generally a tetraalkoxysilane, for example TEOS) and brought to a pH below 2, typically less than 1. According to this specific variant, B 2 O 3 introduced is converted in situ to boron alkoxide, which is then engaged with the silicon alkoxide in the hydrolysis and condensation reactions, whereby an acid boron-doped silica sol is obtained within its network. . In this context, the reaction is preferably conducted at a temperature above 15 ° C, for example between 20 and 50 ° C., typically at a temperature below 40 ° C., which makes it possible to optimize the initial conversion of the boron oxide to alkoxide, so as to obtain an effective incorporation of boron in the silica network, rather than physical inclusions of B 2 O 3 in the structure of the silica.
Quelles que soient ses conditions de mise en œuvre, l'étape (A) conduit à la formation d'un sol de silice dopée ayant une viscosité permettant un dépôt sous forme d'un film sur un support poreux dans l'étape (B). Cette viscosité peut être modulée en jouant sur la durée et la température de formation du sol, la gélification et la viscosité augmentant avec le temps de vieillissement et avec la température. La technique utilisée pour le dépôt du film de l'étape (B) dépend de la nature du support poreux sur lequel ledit film doit être déposé.Whatever its conditions of implementation, step (A) leads to the formation of a doped silica sol having a viscosity allowing deposition in the form of a film on a porous support in step (B) . This viscosity can be modulated by varying the duration and temperature of soil formation, gelation and viscosity increasing with aging time and with temperature. The technique used for the deposition of the film of step (B) depends on the nature of the porous support on which said film is to be deposited.
En fonction de l'application envisagée pour la membrane préparée selon l'invention, le support peut notamment être plan ou tubulaire. Dans le cas d'un support plan, le dépôt de l'étape (B) est généralement réalisé selon la technique dite de "spin coating". Dans le cas d'un support tubulaire, le dépôt de l'étape (B) est plutôt réalisé selon la méthode dite de "slip casting". Ces deux techniques, bien connues, ont notamment été décrites dans l'ouvrage précité "Fundamentals of inorganic membrane science and technology", Elsevier, 1996, p; 183. Dans le cas d'un support tubulaire, le dépôt de l'étape (B) peut être effectué sur la surface externe et/ou sur la surface interne, en fonction de l'application recherchée.Depending on the intended application for the membrane prepared according to the invention, the support may in particular be planar or tubular. In the case of a plane support, the deposition of step (B) is generally carried out according to the so-called "spin coating" technique. In the case of a tubular support, the deposit of step (B) is rather carried out according to the so-called "slip casting" method. These two techniques, well known, have been described in particular in the aforementioned work "Fundamentals of inorganic membrane science and technology", Elsevier, 1996, p; 183. In the case of a tubular support, the deposition of step (B) may be performed on the outer surface and / or on the inner surface, depending on the desired application.
Un moyen très simple pour effectuer le dépôt de l'étape (B) consiste à immerger le support poreux dans le sol de silice dopée. Outre sa grande facilité de mise en œuvre, ce mode de réalisation conduit, de façon surprenante, à un
ancrage particulièrement efficace de la couche de silice sur le support poreux. Sans vouloir être lié à une théorie particulière, il semble pouvoir être avancé que l'immersion du support dans le sol permet d'éliminer substantiellement la présence de gaz entre le support poreux et la couche de silice en formation, ce qui permet d'inhiber les phénomènes de désolidarisation de la couche de silice qui sont observés lors du traitement thermique de l'étape (C) lorsque l'air reste présent dans les pores du support poreux.A very simple way to perform the deposition of step (B) is to immerse the porous support in the doped silica sol. In addition to its great ease of implementation, this embodiment leads, surprisingly, to a particularly effective anchoring of the silica layer on the porous support. Without wishing to be bound to a particular theory, it seems possible to be put forward that the immersion of the support in the soil makes it possible to substantially eliminate the presence of gas between the porous support and the silica layer being formed, which makes it possible to inhibit the phenomena of separation of the silica layer which are observed during the heat treatment of step (C) when the air remains present in the pores of the porous support.
Le support poreux utilisé dans l'étape (B) peut être tout support poreux adapté pour la préparation de membranes de séparation de gaz. Le plus souvent, le dépôt de l'étape (B) est effectué sur un support comprenant une alumine poreuse sur la surface où est effectué Ie dépôt. Selon un mode intéressant, par exemple, le support de l'étape (B) comprend une sous couche à base d'alumine alpha (généralement d'une épaisseur de quelques dizaines ou centaines de microns), sur laquelle est déposée une couche de surface d'alumine gamma (généralement une couche mésoporeuse ayant une épaisseur de l'ordre de quelques microns) destinée à recevoir la couche microporeuse à base de silice dopée déposée selon l'invention.The porous support used in step (B) may be any porous support suitable for the preparation of gas separation membranes. Most often, the deposition of step (B) is carried out on a support comprising a porous alumina on the surface where the deposition is carried out. According to an advantageous mode, for example, the support of step (B) comprises an alpha-alumina-based sub-layer (generally of a thickness of a few tens or hundreds of microns), on which a surface layer is deposited. of gamma alumina (generally a mesoporous layer having a thickness of the order of a few microns) intended to receive the microporous layer based on doped silica deposited according to the invention.
Dans le cadre de la présente invention, les inventeurs ont en outre mis en évidence que l'étape (B) du procédé (et, plus largement, toute étape de dépôt du sol de silice dopé sur un support poreux) peut être optimisée, pour améliorer la cohésion de la couche de silice dopée sur le support poreux.In the context of the present invention, the inventors have furthermore demonstrated that step (B) of the process (and, more generally, any step of depositing the silica sol doped on a porous support) can be optimized, for improve the cohesion of the silica layer doped on the porous support.
A cet effet, les travaux effectués par les inventeurs mettent en évidence qu'il se révèle particulièrement intéressant d'effectuer un prétraitement du support préalablement à l'étape (B), de façon à accroître son affinité pour le film déposé.For this purpose, the work carried out by the inventors shows that it is particularly advantageous to perform a pretreatment of the support prior to step (B), so as to increase its affinity for the deposited film.
Dans ce cadre, il est notamment avantageux de conduire, avant l'étape (B), une étape (A-bis) de prétraitement de la surface du support pour lui conférer des charges de surface opposées à celles de la silice dopée du sol utilisé dans le film déposé dans l'étape (B). Dans le cas du dépôt d'un sol acide de silice dopé, cette étape (A-bis) de prétraitement de la surface sera typiquement réalisée par une base, typiquement de l'ammoniaque (qui sera éliminée lors du traitement
thermique de l'étape (C)). Au contraire, avec un sol basique, il convient plutôt de traiter le support avec un acide, avantageusement éliminable lors de l'étape (C), typiquement de l'acide chlorhydrique ou nitrique. Dans tous les cas, l'étape (A- bis) est typiquement réalisée par immersion. Ainsi, par exemple, dans le cas du dépôt d'un sol acide de silice dopée sur un support ayant une couche de surface à base d'alumine, l'étape (A-bis) préalable à l'étape (B) peut typiquement être effectuée en imprégnant le support à base d'alumine par une solution aqueuse ayant un pH supérieur au point isoélectrique de l'alumine. Ce point isoélectrique étant généralement de l'ordre de 9, le pH de la solution de traitement de la surface à base d'alumine est avantageusement supérieur à 10, par exemple entre 10, typiquement de l'ordre de 10,5.In this context, it is particularly advantageous to conduct, prior to step (B), a step (A-bis) of pretreatment of the surface of the support to give it surface charges opposite to those of the doped silica of the soil used. in the film deposited in step (B). In the case of deposition of a doped silica acid sol, this step (A-bis) of pretreatment of the surface will typically be carried out by a base, typically ammonia (which will be removed during the treatment thermal step (C)). On the contrary, with a basic sol, it is preferable to treat the support with an acid, advantageously removable in step (C), typically hydrochloric or nitric acid. In all cases, step (A-bis) is typically performed by immersion. Thus, for example, in the case of deposition of an acidic silica sol doped on a support having an alumina-based surface layer, step (A-bis) prior to step (B) can typically be carried out by impregnating the alumina-based support with an aqueous solution having a pH greater than the isoelectric point of the alumina. Since this isoelectric point is generally of the order of 9, the pH of the alumina-based surface treatment solution is advantageously greater than 10, for example between 10, typically of the order of 10.5.
Un autre moyen d'augmenter la cohésion, d'ordre plus mécanique, a également été mis en évidence par les inventeurs. Dans ce cadre, les inventeurs ont observé que le départ du solvant présent dans le sol déposé dans l'étape (B) tend à désolidariser la couche de silice du support, par une sorte d'effet de pelage. Pour éviter ce phénomène, le procédé de l'invention comprend avantageusement, préalablement au dépôt du film de l'étape (B), une étape (A- ter) de pré-imprégnation du support poreux par le sol de silice préparé par l'étape (A), suivie d'un rinçage de surface du support, puis d'un traitement thermique du support ainsi rincé. Dans ce cadre, la pré-imprégnation de l'étape (A-ter) est avantageusement conduite en immergeant totalement le support poreux dans le sol de silice, ce qui permet une imprégnation particulièrement efficace des pores du support. En mettant en œuvre l'étape (A-ter) précitée, on obtient, lors du traitement thermique ultérieur de l'étape (C) non pas seulement une couche de surface à base de silice dopée, mais une couche mécaniquement ancrée dans les pores du support poreux, ce qui prévient les phénomènes de pelage de la couche de silice. La pré-imprégnation selon l'étape (A-ter) se révèle particulièrement efficace avec des supports mésoporeux, à savoir comprenant des pores de dimensions typiquement comprises entre 2 et 50 nm.Another means of increasing cohesion, of a more mechanical nature, has also been demonstrated by the inventors. In this context, the inventors have observed that the departure of the solvent present in the soil deposited in step (B) tends to separate the silica layer from the support, by a kind of peeling effect. To avoid this phenomenon, the process of the invention advantageously comprises, prior to the deposition of the film of step (B), a step (A-ter) of pre-impregnation of the porous support with the silica sol prepared by the step (A), followed by a surface rinsing of the support, and then a heat treatment of the thus rinsed support. In this context, the pre-impregnation of step (A-ter) is advantageously carried out by totally immersing the porous support in the silica sol, which allows a particularly effective impregnation of the pores of the support. By carrying out the above-mentioned step (A-ter), during the subsequent heat treatment of step (C), not only a doped silica-based surface layer, but a layer mechanically anchored in the pores is obtained. porous support, which prevents the phenomena of peeling of the silica layer. Pre-impregnation according to step (A-ter) is particularly effective with mesoporous supports, namely comprising pores with dimensions typically between 2 and 50 nm.
Selon un mode de réalisation particulièrement intéressant, le procédé de l'invention comprend à la fois les étapes (A-bis) et (A-ter) précitées. Dans ce cas, l'étape (A-bis) est de préférence conduite préalablement à l'étape (A-ter).
Pour améliorer encore la cohésion entre la couche de silice et le support poreux, il est en général avantageux de prétraiter thermiquement le support poreux préalablement à la mise en œuvre de l'étape (A) et des éventuelles étapes (A-bis) et (A-ter), et ce tout particulièrement lorsque le support poreux est à base d'alumine. Dans ce cadre, le prétraitement thermique du support est typiquement réalisé à une température supérieure à 5000C, par exemple de l'ordre de 6000C.According to a particularly interesting embodiment, the method of the invention comprises both the steps (A-bis) and (A-ter) above. In this case, step (A-bis) is preferably carried out before step (A-ter). To further improve the cohesion between the silica layer and the porous support, it is generally advantageous to pretreat the porous support prior to the implementation of step (A) and any steps (A-bis) and ( A-ter), especially when the porous support is based on alumina. In this context, the thermal pretreatment of the support is typically carried out at a temperature greater than 500 ° C., for example of the order of 600 ° C.
L'étape (B) du procédé de l'invention est avantageusement suivie par une étape de séchage du film déposé sur le support préalable à l'étape (C), qui permet notamment d'améliorer encore la cohésion entre la couche de silice déposée et le support. Ce séchage est en général conduit en laissant le film liquide déposé sur le support pendant 5 à 15 heures, typiquement de 6 à 10 heures, à une température avantageusement comprise entre 60 et 7O0C, typiquement à une température de l'ordre de 65° C.Step (B) of the process of the invention is advantageously followed by a step of drying the film deposited on the support prior to step (C), which in particular makes it possible to further improve the cohesion between the deposited silica layer. and the support. This drying is generally carried out leaving the liquid film deposited on the support for 5 to 15 hours, typically 6 to 10 hours, at a temperature advantageously between 60 and 70 ° C., typically at a temperature of about 65.degree. ° C.
Enfin, l'étape (C) du procédé de l'invention est un traitement thermique qui permet de convertir Ie film déposé dans l'étape (B) en une couche microporeuse céramique à base de silice dopée. Cette étape de traitement thermique peut être conduite dans les conditions usuelles mises en œuvre pour la préparation de membranes de séparation de gaz. Typiquement, ce traitement thermique est réalisé à une température de 300 à 6000C, en général au dessus de 400°C (entre 500 et 6000C par exemple) pendant une durée de quelques heures (typiquement, de l'ordre de 2 heures).Finally, step (C) of the process of the invention is a heat treatment which makes it possible to convert the film deposited in step (B) into a ceramic microporous layer based on doped silica. This heat treatment step can be carried out under the usual conditions used for the preparation of gas separation membranes. Typically, this heat treatment is carried out at a temperature of 300 to 600 ° C., generally above 400 ° C. (for example, between 500 and 600 ° C.) for a duration of a few hours (typically of the order of 2 hours).
Notamment pour éviter une fragilisation de la couche déposée et pour obtenir une répartition homogène de la taille des pores, il convient de préférence d'effectuer le traitement thermique avec de faibles vitesses de montée et de descente en température, typiquement de l'ordre de 0,1 à 5 0C par minute, de préférence inférieures à 2°C par minute, par exemple entre 0,5 et 1 ,5°C par minute, et typiquement de l'ordre de 10C par minute.In particular to avoid embrittlement of the deposited layer and to obtain a homogeneous distribution of the pore size, it is preferable to carry out the heat treatment with low rise and fall in temperature, typically of the order of 0 , 1 to 5 0 C per minute, preferably less than 2 ° C per minute, for example between 0.5 and 1.5 ° C per minute, and typically of the order of 1 0 C per minute.
A l'issue des différentes étapes précitées, on obtient dans le cadre de l'invention une membrane adaptée à la séparation de gaz comportant une
couche microporeuse de silice dopée par un élément trivalent déposée sur un support poreux.At the end of the various steps mentioned above, in the context of the invention there is obtained a membrane adapted to the separation of gases comprising a microporous layer of silica doped with a trivalent element deposited on a porous support.
Les membranes de ce type, susceptibles d'être obtenues selon le procédé de l'invention, constituent un objet particulier de la présente invention.Membranes of this type, obtainable according to the process of the invention, constitute a particular object of the present invention.
A noter que, selon le mode particulier où l'élément dopant trivalent utilisé est le bore, le procédé de la présente invention donne accès à des membranes originales, comprenant une couche microporeuse de silice dopée par du bore, déposée sur un support microporeux. De telles membranes n'ont, à la connaissance des inventeurs, jamais été décrites, et elles constituent, en tant que telles, un autre objet de la présente invention.Note that, according to the particular embodiment in which the trivalent doping element used is boron, the process of the present invention gives access to original membranes, comprising a microporous layer of silica doped with boron, deposited on a microporous support. Such membranes have, to the knowledge of the inventors, never been described, and they constitute, as such, another object of the present invention.
La couche microporeuse à base de silice dopée présente dans les membranes de la présente invention est en général une couche fine ayant une épaisseur comprise entre 50 et 500 nm, typiquement entre 100 et 300 nm.The microporous layer based on doped silica present in the membranes of the present invention is generally a thin layer having a thickness of between 50 and 500 nm, typically between 100 and 300 nm.
Le procédé de l'invention permet par ailleurs d'obtenir des couches microporeuses à base de silice dopée exemptes de défauts, et ce même lorsque le support utilisé a une taille importante.The method of the invention also makes it possible to obtain microporous layers based on doped silica that are free from defects, even when the support used has a large size.
La couche microporeuse à base de silice dopée présente dans les membranes de l'invention est le plus souvent essentiellement (voire exclusivement) constituée de ladite silice dopée, a l'exception d'autres composés ou groupements fonctionnels. En particulier, la couche microporeuse à base de silice dopée des membranes de l'invention est en général exempte de groupements organiques du type de ceux observés dans les couches de silice obtenues selon les procédés sol-gel utilisant des alkyltrialcoxysilanes tels que le méthyltriéthoxysilane.The microporous layer based on doped silica present in the membranes of the invention is most often essentially (or exclusively) constituted by said doped silica, with the exception of other compounds or functional groups. In particular, the doped silica-based microporous layer of the membranes of the invention is generally free of organic groups of the type of those observed in the silica layers obtained by the sol-gel processes using alkyltrialkoxysilanes such as methyltriethoxysilane.
De préférence, la couche microporeuse à base de silice dopée présente dans les membranes de la présente invention contient des pores de dimensions inférieures à 1 nm. A cet effet, il est préférable d'utiliser dans le procédé un sol de silice dopé où la silice est dispersée sous forme d'objets en suspension (particules ou agrégats de particules) ayant des diamètres hydrodynamiques
inférieurs à 10 nm. Les conditions à mettre en œuvre dans l'étape (A) pour obtenir de tels sols sont illustrées dans les exemples ci-après.Preferably, the doped silica-based microporous layer present in the membranes of the present invention contains pores less than 1 nm in size. For this purpose, it is preferable to use in the process a doped silica sol where the silica is dispersed in the form of suspended objects (particles or particle aggregates) having hydrodynamic diameters less than 10 nm. The conditions to be used in step (A) to obtain such sols are illustrated in the examples below.
Les membranes de l'invention comprennent avantageusement leur couche de silice dopée sur un support à base d'alumine du type décrit plus haut dans la présente description. Le plus souvent, cette couche de silice est une couche de surface de la membrane. Toutefois, pour certaines applications particulières, la couche de silice déposée selon le procédé de l'invention peut être ultérieurement recouverte par une autre couche poreuse ou quasi-dense (voire plusieurs autres), par exemple par une couche de revêtement à base de carbure de silicium, permettant par exemple d'effectuer une séparation d'eau.The membranes of the invention advantageously comprise their silica layer doped on an alumina-based support of the type described above in the present description. Most often, this silica layer is a surface layer of the membrane. However, for certain particular applications, the silica layer deposited according to the process of the invention may be subsequently covered by another porous or quasi-dense layer (or several others), for example by a coating layer based on carbide silicon, allowing for example to perform a water separation.
Selon un autre mode de réalisation, les membranes de l'invention peuvent contenir plusieurs couches de silice dopée successives, obtenues typiquement en répétant les étapes (A), (B) et (C).According to another embodiment, the membranes of the invention may contain several successive doped silica layers, typically obtained by repeating steps (A), (B) and (C).
Compte tenu de leurs caractéristiques particulières, les membranes de l'invention sont particulièrement adaptées à la séparation de gaz, et en particulier à la séparation d'hélium ou d'hydrogène dans des mélanges gazeux les comprenant, et ce en particulier à des températures supérieures à 2500C, par exemple à des températures de l'ordre de 300 à 5000C, généralement avec des pressions transmembranaires inférieures à 8 bars. Dans ce cadre, il peut se révéler avantageux de prétraiter thermiquement la membrane préalablement à la séparation de gaz, typiquement à une température supérieure ou égale à 4000C, par exemple entre 500 et 6000C. Cette application spécifique constitue un autre objet de la présente invention.In view of their particular characteristics, the membranes of the invention are particularly suitable for the separation of gases, and in particular for the separation of helium or hydrogen in gaseous mixtures comprising them, and in particular at higher temperatures. at 250 ° C., for example at temperatures of the order of 300 to 500 ° C., generally with transmembrane pressures of less than 8 bar. In this context, it may be advantageous to pretreat the membrane thermally prior to gas separation, typically at a temperature greater than or equal to 400 0 C, for example between 500 and 600 0 C. This specific application is another object of the present invention.
Selon un premier mode de réalisation, les membranes de l'invention comprennent la couche microporeuse de silice dopée déposée sur un support plan. Sous cette forme, elles sont propres à assurer une séparation de gaz à l'état de filtres séparant deux cavités. Dans ce cadre, elles se présentent avantageusement sous forme de plaques ou de disques.According to a first embodiment, the membranes of the invention comprise the microporous layer of doped silica deposited on a plane support. In this form, they are suitable for providing gas separation in the form of filters separating two cavities. In this context, they are advantageously in the form of plates or disks.
Selon un autre mode, généralement plus intéressant, les membranes de l'invention comprennent la couche microporeuse de silice dopée déposée sur la
surface interne ou externe d'un support cylindrique. Ces membranes sont adaptées pour la séparation de gaz selon un mode continu.According to another, generally more advantageous, mode, the membranes of the invention comprise the microporous layer of doped silica deposited on the internal or external surface of a cylindrical support. These membranes are suitable for gas separation in a continuous mode.
Les membranes où la couche microporeuse de silice dopée est déposée sur la surface interne du support cylindrique sont en général utilisées en faisant circuler un mélange gazeux contenant les gaz à extraire dans l'espace interne du cylindre, avec une pression partielle des gaz à extraire plus importante dans cet espace interne qu'à l'extérieur du cylindre. Selon ce mode, on peut par exemple purifier un courant gazeux d'hélium ou d'hydrogène contenant des impuretés, l'hélium ou l'hydrogène étant évacué hors du cylindre et les impuretés y restant emprisonnées.The membranes where the microporous layer of doped silica is deposited on the inner surface of the cylindrical support are generally used by circulating a gaseous mixture containing the gases to be extracted in the internal space of the cylinder, with a partial pressure of the gases to be extracted more important in this internal space than outside the cylinder. According to this mode, it is possible, for example, to purify a gaseous stream of helium or hydrogen containing impurities, helium or hydrogen being discharged from the cylinder and the impurities remaining trapped therein.
A l'inverse, les membranes comprenant la couche microporeuse de silice dopée sur la surface extérieur du support cylindrique sont plutôt destinées à être utilisées en faisant circuler le mélange gazeux contenant les gaz à extraire à l'extérieur du cylindre et en faisant circuler dans l'espace interne du cylindre un courant des gaz à extraire avec une pression partielle réduite par rapport à l'extérieur. Selon ce mode, les gaz à extraire sont entraînés dans le cylindre tandis que les gaz à séparer restent à l'extérieur du cylindre. Ce mode est notamment adapté pour l'extraction de gaz présents en faibles quantités dans un courant gazeux (de l'hydrogène dans des effluents hydrocarbonés par exemple). Les membranes de l'invention, en particulier celles où la couche microporeuse à base de silice dopée contient des pores de dimensions inférieurs à 1 nm, se révèlent particulièrement bien adaptées pour la séparation d'hélium ou d'hydrogène à partir de mélange les comprenant.Conversely, the membranes comprising the microporous silica layer doped on the outer surface of the cylindrical support are rather intended to be used by circulating the gaseous mixture containing the gases to be extracted outside the cylinder and circulating in the internal space of the cylinder a stream of gases to be extracted with a reduced partial pressure relative to the outside. According to this mode, the gases to be extracted are entrained in the cylinder while the gases to be separated remain outside the cylinder. This mode is particularly suitable for extracting gases present in small amounts in a gas stream (hydrogen in hydrocarbon effluents for example). The membranes of the invention, in particular those in which the doped silica-based microporous layer contains pores less than 1 nm in size, are particularly suitable for the separation of helium or hydrogen from a mixture comprising them. .
En particulier, les membranes de ce type sont bien adaptées à l'élimination d'impuretés dans des courants d'hélium.In particular, membranes of this type are well suited to the removal of impurities in helium currents.
Dans ce cadre, les membranes de l'invention trouvent notamment une application très intéressante dans le traitement des courants d'hélium chauds utilisés notamment dans le circuit primaires des réacteurs nucléaires à haute température de nouvelle génération, dits HTR. Dans ces réacteurs, les impuretés telles que CO, CO2 ou ChU . ainsi que des produits de fissions de type Xe ou Kr, qui sont présents dans l'hélium doivent être éliminés, dans la mesure où ils sont source de corrosion. Les membranes de l'invention permettent d'effectuer une
telle séparation de façon efficace, aux températures de travail de l'hélium dans le réacteur (entre 300 et 5000C et sous pression). Dans ce cadre, il est préférable d'utiliser des membranes où la couche microporeuse de silice dopée déposée sur la surface d'un support cylindrique, de préférence sur la surface interne, les membranes de l'invention permettant alors d'effectuer une telle séparation selon un mode continu et de façon efficace et quantitative, avec des perméances pouvant atteindre des valeurs de l'ordre de 10"6 mol.m'2.s'1.Pa'1, et des sélectivités de séparation de l'hélium particulièrement élevées.In this context, the membranes of the invention find particularly useful application in the treatment of hot helium currents used in particular in the primary circuit of high-temperature nuclear reactors of new generation, so-called HTR. In these reactors, impurities such as CO, CO 2 or CHU. as well as Xe or Kr type fission products, which are present in the helium must be eliminated, insofar as they are a source of corrosion. The membranes of the invention make it possible to perform a such separation effectively, at working temperatures of helium in the reactor (between 300 and 500 0 C and under pressure). In this context, it is preferable to use membranes in which the microporous layer of doped silica deposited on the surface of a cylindrical support, preferably on the inner surface, the membranes of the invention then making it possible to perform such a separation. in a continuous mode and in an efficient and quantitative manner, with permeances of up to values of the order of 10 -6 mol.m.sup.- 2 .sup.- 1 .Pa.sup.- 1 , and helium separation selectivities particularly high.
Ainsi, cette utilisation des membranes de l'invention constitue une alternative très intéressante aux procédés actuels de purification des circuits d'hélium des réacteurs de type HTR, où la purification doit être effectuée selon un mode discontinu et à des températures basses atteignant -1800C.Thus, this use of the membranes of the invention constitutes a very interesting alternative to the current processes for purifying the helium circuits of the HTR-type reactors, where the purification must be carried out in a batch mode and at low temperatures up to -180 ° C. vs.
Cette application particulière des membranes de l'invention, ainsi que les installations nucléaires comportant un circuit caloporteur d'hélium muni d'un système de séparation de gaz mettant en œuvre une membrane de séparation de gaz selon l'invention pour la purification de l'hélium, constituent d'autres objets spécifiques de l'invention.This particular application of the membranes of the invention, as well as the nuclear installations comprising a helium heat-carrying circuit provided with a gas separation system implementing a gas separation membrane according to the invention for the purification of the helium, constitute other specific objects of the invention.
En plus des applications spécifiques précitées, les membranes de l'invention trouvent des applications dans de nombreux domaines d'utilisation, compte tenu de leurs multiples avantages.In addition to the specific applications mentioned above, the membranes of the invention find applications in many fields of use, given their multiple advantages.
En particulier, les membranes de l'invention peuvent être utilisées pour extraire de l'hydrogène hb à partir de mélanges gazeux le contenant, comme des effluents de raffineries pétrochimiques, ou pour éliminer des polluants gazeux présents dans un flux d'hydrogène, par exemple préalablement à son introduction dans un réacteur de synthèse, ou bien encore dans des piles à combustibles (notamment de type PEM) où elles permettent, entre autres, d'éliminer les gaz de type CO susceptibles d'empoisonner les catalyseurs. Les membranes de l'invention conduisent également à de très bonnes sélectivités dans le cadre de tels processus de séparation d'hydrogène.In particular, the membranes of the invention can be used to extract hydrogen hydrogen from gaseous mixtures containing it, such as effluents from petrochemical refineries, or to eliminate gaseous pollutants present in a stream of hydrogen, for example prior to its introduction into a synthesis reactor, or even into fuel cells (in particular of the PEM type) where they allow, among other things, to eliminate the CO type gases that can poison the catalysts. The membranes of the invention also lead to very good selectivities in the context of such hydrogen separation processes.
De façon plus générale, les membranes de l'invention peuvent être utilisées dans de nombreux autres domaines où la séparation de gaz est requise,
dans la mesure où elles constituent des perfectionnements très intéressants des membranes actuellement connues. En particulier, les membranes de l'invention sont potentiellement utilisables pour la séparation de l'hydrogène et de gaz ayant un diamètre cinétique supérieur à 0,30 mm, tels que l'azote, l'oxygène, les gaz carbonés (notamment les gaz hydrocarbonés), ou bien encore H2S.More generally, the membranes of the invention can be used in many other fields where gas separation is required. inasmuch as they constitute very interesting improvements of the currently known membranes. In particular, the membranes of the invention are potentially usable for the separation of hydrogen and gases having a kinetic diameter greater than 0.30 mm, such as nitrogen, oxygen, carbonated gases (especially gases hydrocarbon), or even H2S.
Différents aspects et avantages de l'invention ressortiront encore plus nettement des exemples illustratifs exposés ci-après.
Various aspects and advantages of the invention will emerge even more clearly from the illustrative examples set forth below.
EXEMPLE 1EXAMPLE 1
On a préparé une membrane à base d'une couche microporeuse de silice dopée par du bore déposé sur un support à base d'alumine, dans les conditions suivantes :A membrane based on a microporous layer of silica doped with boron deposited on an alumina support was prepared under the following conditions:
• préparation d'un sol de silice dopé par du bore (technique sol-gel)• preparation of a silica sol doped with boron (sol-gel technique)
Dans un ballon bicol équipé d'une colonne à reflux et placé dans un bain chauffant thermostaté à 400C, on a introduit 1 mole de TEOS dans un milieu contenant 4 moles d'eau et 4,5 moles d'éthanol et 0,04 moles d'acide chlorhydrique. A ce milieu, on a introduit 0,1 mole d'oxyde de bore B2O3. Le mélange obtenu a été laissé sous reflux à 400C pendant 3 heures.In a two-neck flask equipped with a reflux column and placed in a heating bath thermostated at 40 ° C., 1 mole of TEOS was introduced into a medium containing 4 moles of water and 4.5 moles of ethanol and 0, 04 moles of hydrochloric acid. To this medium, 0.1 mole of boron oxide B 2 O 3 was introduced . The mixture obtained was refluxed at 40 ° C. for 3 hours.
A l'issue de cette réaction, on a obtenu un sol acide de silice dopée (S), de pH égal à 1 , et ayant une viscosité suffisamment faible pour la mise en œuvre des étapes suivantes.At the end of this reaction, a doped silica sol (S) of pH equal to 1 was obtained and having a sufficiently low viscosity for the implementation of the following steps.
• prétraitement du support d'alumine• pretreatment of alumina support
Le support d'alumine utilisé dans cet exemple est un support à base d'alumine commercialisé par la société PALL EXEKIA ayant la forme d'un cylindre creux (diamètre interne :7 mm, diamètre externe : 10 mm ; longueur : 25 cm) comportant une couche interne à base d'alumine gamma mésoporeuse (diamètre des pores : 5 nm) déposée sur de l'alumine alpha constituant l'extérieur du cylindre.The alumina support used in this example is a carrier based on alumina marketed by PALL EXEKIA in the form of a hollow cylinder (internal diameter: 7 mm, outer diameter: 10 mm, length: 25 cm) comprising an inner layer based on mesoporous gamma-alumina (pore diameter: 5 nm) deposited on alpha alumina constituting the outside of the cylinder.
Ce support a été prétraité thermiquement à 6000C (voire 5500C) selon le profil suivant : montée en température à 1°C/min jusqu'à 600°C, maintien 2h à 6000C, descente en température jusqu'à température ambiante à 1 °C/min.This support was pretreated thermally at 600 ° C. (or 550 ° C.) according to the following profile: temperature rise at 1 ° C./min up to 600 ° C., hold for 2 hours at 600 ° C., temperature decrease to room temperature at 1 ° C / min.
Le support ainsi prétraité thermiquement a ensuite été immergé dans une solution aqueuse d'ammoniaque de pH égal à 10,5 pendant 30 minutes, puis égoutté, de façon à obtenir des charges de surface négatives.
• pré-imprégnation du supportThe thus pretreated heat support was then immersed in an aqueous ammonia solution of pH equal to 10.5 for 30 minutes and then drained, so as to obtain negative surface charges. • pre-impregnation of the support
Le support issu de l'étape précédente a été entièrement immergé dans le sol acide (S) pendant 2 heures puis le support ainsi traité a été rincé par de l'éthanol.The support resulting from the preceding stage was completely immersed in the acidic soil (S) for 2 hours and then the support thus treated was rinsed with ethanol.
On a ensuite séché le support en le laissant à l'étuve à 65°C, pendant 8 heures.The support was then dried by leaving it in an oven at 65 ° C for 8 hours.
Suite à ce séchage, le support a été traité thermiquement à 5500C selon le profil suivant : montée en température à 1°C/min, maintien à 5500C pendant 2 heures, descente en température à 1°C/min.Following this drying, the support was heat-treated at 550 ° C. according to the following profile: rise in temperature at 1 ° C./min, hold at 550 ° C. for 2 hours, decrease in temperature at 1 ° C./min.
• dépôt d'un film du sol de silice sur le support prétraité• deposition of a silica sol film on the pre-treated support
Le support prétraité issu des étapes précédentes a été immergé totalement dans le sol (S) dilué par de l'alcool à 1/6 de sa concentration initiale pendant 2 heures.The pretreated support from the previous steps was immersed completely in the soil (S) diluted with alcohol at 1/6 of its initial concentration for 2 hours.
On a ensuite sorti le support du sol, et on l'a laissé sécher à l'étuve à 65°C pendant 15 heures.The support was then removed from the soil and allowed to dry in an oven at 65 ° C for 15 hours.
A l'issue de ce séchage, le support recouvert par le film a été traité thermiquement dans les conditions suivantes : - montée en température de 200C à 1000C, à raison de 10C par minute ;At the end of this drying, the support covered by the film was heat-treated under the following conditions: - rise in temperature from 20 ° C. to 100 ° C., at a rate of 1 ° C. per minute;
- palier : maintien à 1000C pendant 2 h ; etbearing: hold at 100 ° C. for 2 hours; and
- montée en température jusqu'à 5500C à raison de 10C par minute ;temperature rise up to 550 ° C. at a rate of 1 ° C. per minute;
- palier : maintien à 55O0C pendant 2 heures ;- bearing: maintained at 55O 0 C for 2 hours;
- descente en température jusqu'à 20°C, à raison de 1 ° C par minute. A l'issue de ces étapes, on a obtenu une membrane (M1) selon l'invention.- Lowering temperature to 20 ° C at a rate of 1 ° C per minute. At the end of these steps, a membrane (M1) according to the invention was obtained.
Cette membrane a été testée en effectuant une séparation d'hélium à 3000C à partir d'un mélange à base d'hélium contenant 1 % de CO2 et 1 % de CH4, dans les conditions suivantes :This membrane was tested by carrying out a separation of helium at 300 ° C. from a helium-based mixture containing 1% of CO 2 and 1% of CH 4 under the following conditions:
- séchage du support sous hélium à 25O0C; - température de l'essai de perméation : 250°C à 300°C .
- différence de pression transmembranaire : 1 à 4 bars.drying of the support in helium at 25O 0 C; temperature of the permeation test: 250 ° C to 300 ° C. - transmembrane pressure difference: 1 to 4 bars.
On a obtenu une séparation d'hélium avec les caractéristiques suivantes :Helium separation was obtained with the following characteristics:
- perméance : 10'6 mol.m'2.s"1.Pa"1 permeance: 10 '6 mol.m ' 2 .s "1 .Pa -1
- sélectivité He/CO2 : 18 - sélectivité He/CH4 : 21.
- He / CO 2 selectivity: 18 - He / CH 4 : 21 selectivity.
EXEMPLE 2EXAMPLE 2
Dans ce second exemple, on a préparé une membrane à base d'une double couche microporeuse de silice dopée par du bore, déposée sur un support à base d'alumine, dans les conditions suivantes :In this second example, a membrane based on a microporous double layer of silica doped with boron, deposited on an alumina support, was prepared under the following conditions:
2.1 préparation du support2.1 support preparation
Le support d'alumine utilisé dans cet exemple est un support à base d'alumine commercialisé par la société PALL EXEKIA ayant la forme d'un cylindre creux (diamètre interne :7 mm, diamètre externe : 10 mm ; longueur : 25 cm) comportant une couche interne à base d'alumine gamma mésoporeuse (diamètre des pores : 5 nm) déposée sur de l'alumine alpha constituant l'extérieur du cylindre.The alumina support used in this example is a carrier based on alumina marketed by PALL EXEKIA in the form of a hollow cylinder (internal diameter: 7 mm, outer diameter: 10 mm, length: 25 cm) comprising an inner layer based on mesoporous gamma-alumina (pore diameter: 5 nm) deposited on alpha alumina constituting the outside of the cylinder.
• Prétraitement thermique• Thermal pre-treatment
Le support a tout d'abord été prétraité thermiquement, pour "ouvrir" les pores de l'alumine. Ce traitement a été opéré à 6000C (voire 5500C) selon le profil suivant : montée en température à 1°C/min jusqu'à 6000C, maintien 2h à 600°C, descente en température jusqu'à température ambiante à 1°C/min.The support was first thermally pretreated to "open" the pores of the alumina. This treatment was carried out at 600 ° C. (or even 550 ° C.) according to the following profile: rise in temperature at 1 ° C./min up to 600 ° C., hold for 2 hours at 600 ° C., lowering temperature to temperature ambient at 1 ° C / min.
• Formation d'une couche intermédiaire silice/alumine• Formation of an intermediate silica / alumina layer
Suite au traitement thermique, le support a été immergé dans une solution aqueuse d'ammoniaque de pH égal à 10,5, pendant 30 minutes, puis égoutté. On a ensuite immergé le support dans un sol (SSÎ/AI) de silice/alumine obtenu en mélangeant :Following the heat treatment, the support was immersed in an aqueous ammonia solution of pH equal to 10.5, for 30 minutes, and then drained. The support was then immersed in silica / alumina sol (S Si / Al ) obtained by mixing:
- 1 mole de TEOS- 1 mole of TEOS
- 4,5 moles d'éthanol- 4.5 moles of ethanol
- 0,04 mole d'acide chlorhydrique - 4 moles d'eau- 0.04 moles hydrochloric acid - 4 moles water
-1 ,5 moles de boehmite (voire 1 à 2 moles) pendant 2 à 5 heures. Le tube est lavé à l'éthanol.
Le support a ensuite été séché sous étuve à 65°C pendant 8 à 12 heures en position verticale.-1.5 moles of boehmite (even 1 to 2 moles) for 2 to 5 hours. The tube is washed with ethanol. The support was then dried in an oven at 65 ° C for 8 to 12 hours in an upright position.
Suite à ce séchage, le support a été traité thermiquement à 5500C selon la profil suivant : montée en température à 1 °C/min, maintien à 5500C pendant 2 heures, descente en température à 1°C/min.Following this drying, the support was heat-treated at 550 ° C. according to the following profile: rise in temperature at 1 ° C./min, hold at 550 ° C. for 2 hours, decrease in temperature at 1 ° C./min.
• Pré-imprégnation du support• Pre-impregnation of the support
Suite aux différentes étapes précédentes, on a de nouveau immergé le support dans une solution aqueuse d'ammoniaque de pH égal à 10,5, pendant 30 minutes, puis on l'a égoutté. Le support a ensuite été entièrement immergé pendant 2 heures dans le sol acide (S) décrit dans l'exemple 1 , puis le support ainsi traité a été rincé par de l'éthanol.Following the various previous steps, the support was again immersed in an aqueous solution of ammonia with a pH of 10.5 for 30 minutes and then drained. The support was then completely immersed for 2 hours in the acidic soil (S) described in Example 1, and the support thus treated was rinsed with ethanol.
On a ensuite séché le support en le laissant à l'étuve à 65°C, pendant 8 à 12 heures. Suite à ce séchage, le support a été traité thermiquement à 5500C selon la profil suivant : montée en température à 1°C/min, maintien à 5500C pendant 2 heures, descente en température à 1°C/min.The support was then dried by leaving it in an oven at 65 ° C for 8 to 12 hours. Following this drying, the support was heat-treated at 550 ° C. according to the following profile: rise in temperature at 1 ° C./min, hold at 550 ° C. for 2 hours, decrease in temperature at 1 ° C./min.
2.2 dépôt de la double couche de silice dopée par du bore2.2 deposition of the double layer of silica doped with boron
• dépôt de la première couche Le support prétraité issu des étapes précédentes a été immergé totalement dans le sol (S), dilué par de l'alcool à 1/6 de sa concentration initiale, pendant 2 heures.Deposit of the first layer The pretreated support from the previous steps was immersed completely in the soil (S), diluted with alcohol to 1/6 of its initial concentration, for 2 hours.
A nouveau, le support a été séché sous étuve à 65°C pendant 8 à 12 heures en position verticale, puis soumis à un traitement thermique à 5500C (montée en température à 1 °C/min, maintien à 550°C pendant 2 heures, descente en température à 1°C/min).Again, the support was dried in an oven at 65 ° C for 8 to 12 hours in a vertical position, then subjected to heat treatment at 550 0 C (temperature rise at 1 ° C / min, holding at 550 ° C for 2 hours, lowering temperature to 1 ° C / min).
On a ainsi obtenu Ie dépôt d'une première couche microporeuse de silice dopée par du bore.
• dépôt de la seconde coucheThe deposition of a first microporous layer of silica doped with boron was thus obtained. • deposit of the second layer
Le support recouvert ainsi obtenu a été immergé totalement, premièrement 3 minutes dans de l'éthanol, puis deuxièmement dans le sol (S), dilué par de l'alcool à 1/12 de sa concentration initiale, pendant 2 heures. Suite à cette nouvelle immersion, le support a à nouveau été séché sous étuve à 65°C pendant 12 heures en position verticale, puis soumis à un traitement thermique à 5500C (montée en température à 1 °C/min, maintien à 5500C pendant 2 heures, descente en température à 1 °C/min).The coated support thus obtained was immersed completely, firstly for 3 minutes in ethanol, then secondly in the soil (S), diluted with alcohol at 1/12 of its initial concentration, for 2 hours. Following this new immersion, the support was again dried in an oven at 65 ° C for 12 hours in a vertical position, then subjected to a heat treatment at 550 0 C (temperature rise at 1 ° C / min, maintenance at 550 0 C for 2 hours, lowering temperature to 1 ° C / min).
A l'issue de ces étapes, on a obtenu une membrane (M2) selon l'invention.
At the end of these steps, a membrane (M2) was obtained according to the invention.
Claims
1. Procédé de préparation d'une membrane de séparation de gaz, comprenant le dépôt d'un film d'un sol de silice sur un support poreux, puis le traitement thermique du film ainsi déposé, caractérisé en ce que le sol de silice qui est déposé sous forme de film sur le support poreux est préparé en hydrolysant un alcoxyde de silicium en présence d'une quantité dopante d'un précurseur d'un oxyde d'un élément trivalent où ledit élément trivalent est le bore.A process for preparing a gas separation membrane, comprising depositing a film of a silica sol on a porous support, and then the heat treatment of the film thus deposited, characterized in that the silica sol which is deposited as a film on the porous support is prepared by hydrolyzing a silicon alkoxide in the presence of a doping amount of a precursor of an oxide of a trivalent element wherein said trivalent element is boron.
2. Procédé selon la revendication 1 , où le précurseur d'oxyde de bore utilisé est un alcoxyde ou un acide de bore.2. The method of claim 1, wherein the boron oxide precursor used is an alkoxide or a boron acid.
3. Procédé selon l'une des revendications 1 ou 2, où le précurseur d'oxyde de bore utilisé est introduit dans le milieu d'hydrolyse de l'alcoxyde de silicium :3. Method according to one of claims 1 or 2, wherein the boron oxide precursor used is introduced into the hydrolysis medium of the silicon alkoxide:
- sous la forme d'au moins un composé répondant à la formule (I) suivante :in the form of at least one compound corresponding to the following formula (I):
M(OR)3 formule (I) ou bienM (OR) 3 formula (I) or
- sous la forme d'au moins un composé ayant la formule (I1) suivantein the form of at least one compound having the following formula (I 1 )
M(OH)3 formule (I1) où : - M désigne le bore ; et - les 3 groupements R sont identiques ou différents, chacun représentant une chaîne hydrocarbonée comprenant de 1 à 8 atomes de carbone.M (OH) 3 formula (I 1 ) wherein: - M is boron; and the 3 R groups are identical or different, each representing a hydrocarbon chain comprising from 1 to 8 carbon atoms.
4. Procédé selon l'une des revendications 1 à 3, où l'alcoxyde de bore est formé in situ, en introduisant dans le milieu d'hydrolyse de l'alcoxyde de silicium de l'oxyde de bore B2O3 et un alcool de formule ROH, où R a la signification donnée dans la revendication 3.4. Method according to one of claims 1 to 3, wherein the boron alkoxide is formed in situ, by introducing into the hydrolysis medium of the silicon alkoxide boron oxide B 2 O 3 and a an alcohol of formula ROH, wherein R has the meaning given in claim 3.
5. Procédé selon l'une des revendications 1 à 6, où le précurseur d'oxyde de bore est introduit dans le milieu de formation de la silice avec un rapport molaire élément trivalent / silicium compris entre 1 : 100 et 1 : 1 , de préférence entre 1 :20 et 1 : 2.5. Method according to one of claims 1 to 6, wherein the precursor of boron oxide is introduced into the silica-forming medium with a molar ratio trivalent element / silicon between 1: 100 and 1: 1, preferably between 1: 20 and 1: 2.
6. Procédé selon l'une des revendications 1 à 5, qui comporte les étapes successives suivantes : (A) selon la technique sol-gel, on réalise un sol de silice dopée par du bore, en hydrolysant un alcoxyde de silicium au sein d'un milieu hydroalcoolique contenant une quantité dopante d'un précurseur d'un oxyde de bore ;6. Method according to one of claims 1 to 5, which comprises the following successive steps: (A) according to the sol-gel technique, a boron-doped silica sol is produced, by hydrolyzing a silicon alkoxide within an aqueous-alcoholic medium containing a doping amount of a precursor of a boron oxide;
(B) on dépose le sol ainsi préparé sur un support poreux ; et (C) on traite thermiquement le film ainsi déposé, ce par quoi on le convertit en une couche microporeuse céramique à base de silice dopée par du bore.(B) the soil thus prepared is deposited on a porous support; and (C) the deposited film is heat-treated, whereby it is converted into a ceramic microporous ceramic layer doped with boron.
7. Procédé selon la revendication 8, où, dans le milieu de l'étape (A), la concentration en alcoxyde de silicium est comprise entre 0,3 et 4 mol/L.7. The method of claim 8, wherein in the middle of step (A), the concentration of silicon alkoxide is between 0.3 and 4 mol / L.
8. Procédé selon la revendication 6 ou 7, où l'étape (A) est conduite en introduisant de l'oxyde de bore B2O3 dans un milieu hydro-alcoolique contenant un alcoxyde de silicium et porté à un pH inférieur à 2.8. A process according to claim 6 or 7, wherein step (A) is carried out by introducing boron oxide B 2 O 3 in a hydroalcoholic medium containing a silicon alkoxide and brought to a pH below 2. .
9. Procédé selon l'une des revendications 6 à 8, où le dépôt de l'étape (B) est réalisé sur un support comprenant une alumine poreuse sur la surface où est effectuée le dépôt.9. Method according to one of claims 6 to 8, wherein the deposition of step (B) is carried out on a support comprising a porous alumina on the surface where the deposition is performed.
10. Procédé selon l'une des revendications 6 à 9, qui comprend, préalablement à l'étape (B), une étape (A-bis) de prétraitement de la surface du support pour lui conférer des charges de surface opposées à celles de la silice dopée du sol utilisé dans le film déposé dans l'étape (B).10. Method according to one of claims 6 to 9, which comprises, prior to step (B), a step (A-bis) of pretreatment of the surface of the support to give it surface charges opposite to those of the doped silica of the sol used in the film deposited in step (B).
11. Procédé selon la revendication 10, où le sol préparé dans l'étapeThe method of claim 10, wherein the soil prepared in step
(A) est un sol acide de silice dopée et où le support utilisé dans l'étape (B) a une couche de surface à base d'alumine, et dans lequel l'étape (A-bis) est effectuée en imprégnant le support à base d'alumine par une solution aqueuse ayant un pH supérieur au point isoélectrique de l'alumine. (A) is a doped silica acid sol and wherein the support used in step (B) has an alumina-based surface layer, and wherein step (A-bis) is performed by impregnating the support based on alumina with an aqueous solution having a pH greater than the isoelectric point of the alumina.
12. Procédé selon l'une des revendications 6 à 11 , qui comprend, préalablement au dépôt du film de l'étape (B), une étape (A-ter) de préimprégnation du support poreux par Ie sol de silice préparé par l'étape (A) suivie d'un rinçage de surface du support, puis d'un traitement thermique du support ainsi rincé.12. Method according to one of claims 6 to 11, which comprises, prior to the deposition of the film of step (B), a step (A-ter) prepreg of the porous support by the silica sol prepared by the step (A) followed by a surface rinsing of the support, and then a heat treatment of the thus rinsed support.
13. Procédé selon l'une quelconque des revendications 6 à 12, dans lequel l'étape (B) est effectuée en immergeant le support poreux dans le sol.The method of any one of claims 6 to 12, wherein step (B) is performed by immersing the porous support in the soil.
14. Membrane comportant une couche microporeuse de silice dopée par du bore déposée sur un support poreux, susceptible d'être obtenue selon le procédé de l'une quelconque des revendications 1 à 13.14. Membrane comprising a microporous layer of silica doped with boron deposited on a porous support, obtainable by the method of any one of claims 1 to 13.
15. Membrane adaptée à la séparation de gaz, comprenant une couche microporeuse de silice dopée par du bore, déposée sur un support mésoporeux.15. Membrane adapted to the gas separation, comprising a microporous layer of silica doped with boron, deposited on a mesoporous support.
16. Membrane selon la revendication 14 ou 15, où la couche microporeuse à base de silice dopée par du bore a une épaisseur comprise entre 50 et 500 nm.16. Membrane according to claim 14 or 15, wherein the boron-doped silica-based microporous layer has a thickness between 50 and 500 nm.
17. Utilisation d'une membrane selon l'une quelconque des revendications 14 à 16, pour la séparation d'hélium ou d'hydrogène dans des mélanges gazeux les comprenant.17. Use of a membrane according to any one of claims 14 to 16 for the separation of helium or hydrogen in gaseous mixtures comprising them.
18. Utilisation selon la revendication 17, où la séparation est effectuée à une température supérieure à 2500C.18. Use according to claim 17, wherein the separation is carried out at a temperature greater than 250 ° C.
19. Installation nucléaire comportant un circuit caloporteur d'hélium, muni d'un système de séparation de gaz pour la purification de l'hélium mettant en œuvre une membrane selon l'une quelconque des revendications 14 à 16. 19. Nuclear installation comprising a helium heat transport circuit, provided with a gas separation system for the purification of helium using a membrane according to any one of claims 14 to 16.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| FR0513150A FR2895275B1 (en) | 2005-12-22 | 2005-12-22 | GAS SEPARATION MEMBRANES CONTAINING SILICA MICROPOROUS SILICA LAYER DOPED BY TRIVALENT ELEMENT |
| PCT/FR2006/002858 WO2007077358A1 (en) | 2005-12-22 | 2006-12-22 | Gas separation membranes containing a microporous silica layer based on silica doped with a trivalent element |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| EP1971422A1 true EP1971422A1 (en) | 2008-09-24 |
Family
ID=36622559
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP06847128A Withdrawn EP1971422A1 (en) | 2005-12-22 | 2006-12-22 | Gas separation membranes containing a microporous silica layer based on silica doped with a trivalent element |
Country Status (10)
| Country | Link |
|---|---|
| US (1) | US20090090241A1 (en) |
| EP (1) | EP1971422A1 (en) |
| JP (1) | JP5497297B2 (en) |
| KR (1) | KR101408749B1 (en) |
| CN (1) | CN101616726B (en) |
| BR (1) | BRPI0621103A2 (en) |
| CA (1) | CA2634204C (en) |
| FR (1) | FR2895275B1 (en) |
| RU (1) | RU2418622C2 (en) |
| WO (1) | WO2007077358A1 (en) |
Families Citing this family (21)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20090107330A1 (en) * | 2007-10-30 | 2009-04-30 | Yunfeng Gu | Amorphous silica hybrid membrane structure |
| US9745191B2 (en) | 2011-04-11 | 2017-08-29 | Saudi Arabian Oil Company | Auto thermal reforming (ATR) catalytic structures |
| US8597383B2 (en) | 2011-04-11 | 2013-12-03 | Saudi Arabian Oil Company | Metal supported silica based catalytic membrane reactor assembly |
| CN102258941A (en) * | 2011-04-14 | 2011-11-30 | 李书伟 | Modified activated molecular sieve odor removing spraying agent solution, and preparation method thereof |
| JP5882820B2 (en) * | 2011-04-26 | 2016-03-09 | 東洋ゴム工業株式会社 | Methane separation membrane, carbon dioxide separation membrane, and production method thereof |
| RU2492914C2 (en) * | 2012-04-03 | 2013-09-20 | Федеральное государственное бюджетное учреждение науки Институт высокотемпературной электрохимии Уральского отделения Российской Академии наук | Molecular filter to extract helium from helium-bearing gas mixes |
| JP6153235B2 (en) * | 2012-09-21 | 2017-06-28 | アップル インコーポレイテッド | Oil repellent coating on sapphire |
| US9718249B2 (en) | 2012-11-16 | 2017-08-01 | Apple Inc. | Laminated aluminum oxide cover component |
| EP2778252A3 (en) | 2013-03-15 | 2014-12-10 | Apple Inc. | Layered Coatings For Sapphire Structure |
| DE102013004559B4 (en) | 2013-03-18 | 2015-07-23 | Apple Inc. | Shatter-resistant sapphire disk and method of making the same |
| DE102013004558B4 (en) | 2013-03-18 | 2018-04-05 | Apple Inc. | Method for producing a surface-strained sapphire disk, surface-strained sapphire disk and electrical device with a transparent cover |
| DE112016005301T5 (en) | 2015-11-18 | 2018-08-02 | Ngk Insulators, Ltd. | Repair method for a separation membrane and a method for producing a separation membrane structure |
| KR20180104708A (en) | 2016-02-02 | 2018-09-21 | 유니버시티 오브 워싱턴 | Ceramic selective film |
| US10480084B1 (en) * | 2016-03-03 | 2019-11-19 | Marathon Systems, Inc. | Modular cooling chamber for manifold of gaseous electrolysis apparatus with helium permeable element therefor |
| US10888824B2 (en) * | 2016-11-16 | 2021-01-12 | Ppg Industries Ohio, Inc. | Methods for treating filled microporous membranes |
| US10183274B2 (en) * | 2016-11-16 | 2019-01-22 | Ppg Industries Ohio, Inc. | Methods for treating filled microporous membranes |
| EP3735314A4 (en) | 2018-01-04 | 2021-09-29 | University of Washington | Nanoporous selective sol-gel ceramic membranes, selective -membrane structures, and related methods |
| US11269374B2 (en) | 2019-09-11 | 2022-03-08 | Apple Inc. | Electronic device with a cover assembly having an adhesion layer |
| CN111097297B (en) * | 2019-12-30 | 2021-10-26 | 江西师范大学 | Boron-doped microporous silicon dioxide membrane and application |
| CN113488376B (en) * | 2021-07-21 | 2024-04-16 | 山东大学深圳研究院 | Two-dimensional silicon dioxide and preparation method and application thereof |
| CN113912069B (en) * | 2021-10-20 | 2022-12-16 | 马惠琪 | Preparation method of nano-silica sol particles for catalysis |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5589153A (en) * | 1994-11-03 | 1996-12-31 | The Dow Chemical Company | Synthesis of crystalline porous solids in ammonia |
| US6177373B1 (en) * | 1996-03-14 | 2001-01-23 | Exxon Chemicals Patents Inc | Procedure for preparing molecular sieve films |
| US20030116061A1 (en) * | 2001-07-31 | 2003-06-26 | Fuji Photo Film Co., Ltd. | Inorganic composition, film, and method of producing film |
Family Cites Families (13)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5057295A (en) * | 1984-04-13 | 1991-10-15 | Uop | Boron-aluminum-phosphorus-silicon-oxide molecular sieve compositions |
| JPS61212309A (en) * | 1985-03-15 | 1986-09-20 | Tdk Corp | Gas separation process |
| JPS62144713A (en) * | 1985-12-18 | 1987-06-27 | Toppan Printing Co Ltd | Manufacturing method of selective penetrating material |
| JPH0691931B2 (en) * | 1986-03-31 | 1994-11-16 | 株式会社島津製作所 | Gas separation membrane and manufacturing method |
| JPH03126733A (en) * | 1989-10-11 | 1991-05-29 | Toray Ind Inc | Inorganic filler |
| EP0586745B1 (en) * | 1992-09-07 | 1996-01-10 | Shell Internationale Researchmaatschappij B.V. | Manufacturing a ceramic membrane |
| JP2642860B2 (en) * | 1994-02-04 | 1997-08-20 | 工業技術院長 | Inorganic xerogel membrane, method for producing the same, and gas separation membrane comprising inorganic xerogel membrane |
| JPH0857276A (en) * | 1994-08-19 | 1996-03-05 | Kyocera Corp | Production of inorganic separation membrane |
| US5954869A (en) * | 1997-05-07 | 1999-09-21 | Bioshield Technologies, Inc. | Water-stabilized organosilane compounds and methods for using the same |
| JP3971546B2 (en) * | 2000-03-03 | 2007-09-05 | 株式会社ノリタケカンパニーリミテド | Porous ceramic laminate and method for producing the same |
| JP2001276586A (en) * | 2000-03-29 | 2001-10-09 | Kyocera Corp | Gas separation membrane and its production method |
| AUPQ811300A0 (en) * | 2000-06-09 | 2000-07-06 | University Of Queensland, The | Improved silica membrane and process of production therefor |
| CN1278438C (en) * | 2000-09-25 | 2006-10-04 | 三星Sdi株式会社 | Active positive electrode material for rechargeable Li battery and its prepn |
-
2005
- 2005-12-22 FR FR0513150A patent/FR2895275B1/en not_active Expired - Fee Related
-
2006
- 2006-12-22 EP EP06847128A patent/EP1971422A1/en not_active Withdrawn
- 2006-12-22 CN CN2006800524640A patent/CN101616726B/en not_active Expired - Fee Related
- 2006-12-22 CA CA2634204A patent/CA2634204C/en not_active Expired - Fee Related
- 2006-12-22 WO PCT/FR2006/002858 patent/WO2007077358A1/en active Application Filing
- 2006-12-22 US US12/158,410 patent/US20090090241A1/en not_active Abandoned
- 2006-12-22 KR KR1020087017786A patent/KR101408749B1/en not_active IP Right Cessation
- 2006-12-22 JP JP2008546526A patent/JP5497297B2/en not_active Expired - Fee Related
- 2006-12-22 RU RU2008130104/05A patent/RU2418622C2/en not_active IP Right Cessation
- 2006-12-22 BR BRPI0621103-8A patent/BRPI0621103A2/en not_active IP Right Cessation
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5589153A (en) * | 1994-11-03 | 1996-12-31 | The Dow Chemical Company | Synthesis of crystalline porous solids in ammonia |
| US6177373B1 (en) * | 1996-03-14 | 2001-01-23 | Exxon Chemicals Patents Inc | Procedure for preparing molecular sieve films |
| US20030116061A1 (en) * | 2001-07-31 | 2003-06-26 | Fuji Photo Film Co., Ltd. | Inorganic composition, film, and method of producing film |
Non-Patent Citations (2)
| Title |
|---|
| APARICIO M ET AL: "Thick sol-gel coatings based on the B2O3-SiO2 system", JOURNAL OF NON-CRYSTALLINE SOLIDS, NORTH-HOLLAND PHYSICS PUBLISHING. AMSTERDAM, NL, vol. 218, 1 September 1997 (1997-09-01), pages 146 - 150, XP004095566, ISSN: 0022-3093, DOI: 10.1016/S0022-3093(97)00073-2 * |
| NAITO M ET AL: "Process conditions on the preparation of supported microporous SiO2 membranes by sol-gel modification techniques", JOURNAL OF MEMBRANE SCIENCE, ELSEVIER SCIENTIFIC PUBL.COMPANY. AMSTERDAM, NL, vol. 129, no. 2, 9 July 1997 (1997-07-09), pages 263 - 269, XP004084478, ISSN: 0376-7388, DOI: 10.1016/S0376-7388(97)00020-3 * |
Also Published As
| Publication number | Publication date |
|---|---|
| US20090090241A1 (en) | 2009-04-09 |
| CN101616726A (en) | 2009-12-30 |
| FR2895275B1 (en) | 2008-07-25 |
| JP2009520594A (en) | 2009-05-28 |
| RU2418622C2 (en) | 2011-05-20 |
| CN101616726B (en) | 2013-04-10 |
| CA2634204A1 (en) | 2007-07-12 |
| CA2634204C (en) | 2015-02-10 |
| KR20090013160A (en) | 2009-02-04 |
| JP5497297B2 (en) | 2014-05-21 |
| FR2895275A1 (en) | 2007-06-29 |
| WO2007077358A1 (en) | 2007-07-12 |
| KR101408749B1 (en) | 2014-06-17 |
| RU2008130104A (en) | 2010-01-27 |
| BRPI0621103A2 (en) | 2011-11-29 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CA2634204C (en) | Gas separation membranes containing a microporous silica layer based on silica doped with a trivalent element | |
| EP0624560B1 (en) | Preparation of silicium carbide foam from a polyurethane foam impregnated with silicium-containing resin | |
| EP1519789A1 (en) | Method for preparing catalysts for heterogeneous catalysis by multiple-phase impregnation, catalysts and use of said catalysts | |
| JP5897458B2 (en) | Pervaporation separation method | |
| EP2933014A1 (en) | Separation membrane for treatment of gases containing acidic gas, method for producing same, method for separating acidic gas or methane gas, and method for producing acidic gas or methane gas | |
| FR2916366A1 (en) | TEXTURE PARTICLE FILTER FOR CATALYTIC APPLICATIONS | |
| CA2268808C (en) | Inorganic nanofiltration membrane and its application in the sugar industry | |
| JP2013049053A (en) | Systems and methods for using boehmite bond-coat with polyimide membranes for gas separation | |
| WO2010138498A1 (en) | Hybrid composition and membrane based on silylated hydrophilic polymer | |
| FR2926396A1 (en) | METHOD FOR MANUFACTURING AMORPHOUS HYDROGENIC SILICON CARBIDE FILMS WITH THROUGH PORES AND FILMS THUS OBTAINED | |
| JP4858954B2 (en) | Mesoporous silicon carbide film and method for manufacturing the same | |
| CN114340764A (en) | Hybrid inorganic oxide-carbon molecular sieve membranes | |
| EP3233253B1 (en) | Filters comprising oxygen-depleted sic membranes | |
| JP2013237015A (en) | Porous body with carbon film and method of manufacturing the same | |
| WO2006067156A1 (en) | Membrane for the filtration of molecular gases, such as hydrogen, and preparation method thereof | |
| JP2005095851A (en) | Fluid separation filter and its production method | |
| FR2860730A1 (en) | Production of porous element comprises impregnating first porous material with second porous material of lower porosity which then gels | |
| EP1562859B1 (en) | Method for preparing monolithic hydrated aluminas and composite materials | |
| EP1369167A1 (en) | Process for the preparation of a thin zeolitic membrane | |
| Yang et al. | Organic-templating approach to synthesis of nanoporous silica composite membranes (l): TPA-templating and CO 2 separation | |
| EP0236398A1 (en) | Thin microporous layers with open porosity having conduction properties. | |
| CN114432893A (en) | Fluorine-containing pervaporation membrane and preparation method thereof | |
| KR20000030932A (en) | Method for the preparation of alumina-silica composite membrane impregnated with palladium through multi-stage pore structure improvement processing | |
| CN117298882A (en) | Preparation method of silicon dioxide modified polysulfone membrane | |
| JPS6260932B2 (en) |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
|
| 17P | Request for examination filed |
Effective date: 20080616 |
|
| AK | Designated contracting states |
Kind code of ref document: A1 Designated state(s): AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HU IE IS IT LI LT LU LV MC NL PL PT RO SE SI SK TR |
|
| 17Q | First examination report despatched |
Effective date: 20090708 |
|
| DAX | Request for extension of the european patent (deleted) | ||
| STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: EXAMINATION IS IN PROGRESS |
|
| STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |
|
| 18D | Application deemed to be withdrawn |
Effective date: 20170104 |
|
| STAA | Information on the status of an ep patent application or granted ep patent |
Free format text: STATUS: THE APPLICATION IS DEEMED TO BE WITHDRAWN |