JP2004136223A - Catalyst for dimethyl ether reformation and production method for hydrogen-containing gas using the catalyst - Google Patents
Catalyst for dimethyl ether reformation and production method for hydrogen-containing gas using the catalyst Download PDFInfo
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- JP2004136223A JP2004136223A JP2002304183A JP2002304183A JP2004136223A JP 2004136223 A JP2004136223 A JP 2004136223A JP 2002304183 A JP2002304183 A JP 2002304183A JP 2002304183 A JP2002304183 A JP 2002304183A JP 2004136223 A JP2004136223 A JP 2004136223A
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- alumina
- dimethyl ether
- catalyst
- boehmite
- zinc
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- LCGLNKUTAGEVQW-UHFFFAOYSA-N Dimethyl ether Chemical compound COC LCGLNKUTAGEVQW-UHFFFAOYSA-N 0.000 title claims abstract description 96
- 239000003054 catalyst Substances 0.000 title claims abstract description 72
- 239000007789 gas Substances 0.000 title claims abstract description 23
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 title claims abstract description 20
- 229910052739 hydrogen Inorganic materials 0.000 title claims abstract description 18
- 239000001257 hydrogen Substances 0.000 title claims abstract description 17
- 238000004519 manufacturing process Methods 0.000 title claims description 9
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims abstract description 98
- 229910001593 boehmite Inorganic materials 0.000 claims abstract description 34
- FAHBNUUHRFUEAI-UHFFFAOYSA-M hydroxidooxidoaluminium Chemical compound O[Al]=O FAHBNUUHRFUEAI-UHFFFAOYSA-M 0.000 claims abstract description 34
- 239000010949 copper Substances 0.000 claims abstract description 32
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 29
- 229910052802 copper Inorganic materials 0.000 claims abstract description 28
- 239000011701 zinc Substances 0.000 claims abstract description 27
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims abstract description 24
- 229910052725 zinc Inorganic materials 0.000 claims abstract description 23
- 239000002243 precursor Substances 0.000 claims abstract description 19
- 239000000203 mixture Substances 0.000 claims abstract description 18
- 238000002156 mixing Methods 0.000 claims abstract description 10
- 238000002407 reforming Methods 0.000 claims description 23
- 238000001354 calcination Methods 0.000 claims description 6
- 238000010304 firing Methods 0.000 claims description 6
- 238000000975 co-precipitation Methods 0.000 claims description 3
- 230000000694 effects Effects 0.000 abstract description 18
- 238000000034 method Methods 0.000 abstract description 15
- 238000000629 steam reforming Methods 0.000 abstract description 14
- 230000001747 exhibiting effect Effects 0.000 abstract 1
- 238000006243 chemical reaction Methods 0.000 description 22
- 239000002244 precipitate Substances 0.000 description 13
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 12
- XLOMVQKBTHCTTD-UHFFFAOYSA-N Zinc monoxide Chemical compound [Zn]=O XLOMVQKBTHCTTD-UHFFFAOYSA-N 0.000 description 12
- 239000000843 powder Substances 0.000 description 12
- 229910052751 metal Inorganic materials 0.000 description 11
- 239000002184 metal Substances 0.000 description 11
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 10
- 229910052782 aluminium Inorganic materials 0.000 description 10
- 238000011156 evaluation Methods 0.000 description 8
- 150000003839 salts Chemical class 0.000 description 8
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 7
- -1 naphtha Chemical class 0.000 description 7
- 239000002002 slurry Substances 0.000 description 7
- 239000000126 substance Substances 0.000 description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 6
- 239000002994 raw material Substances 0.000 description 6
- 239000011787 zinc oxide Substances 0.000 description 6
- 239000007864 aqueous solution Substances 0.000 description 5
- 239000001569 carbon dioxide Substances 0.000 description 5
- 229910002092 carbon dioxide Inorganic materials 0.000 description 5
- 229910002091 carbon monoxide Inorganic materials 0.000 description 5
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 4
- 150000001639 boron compounds Chemical class 0.000 description 4
- 239000011268 mixed slurry Substances 0.000 description 4
- 239000000047 product Substances 0.000 description 4
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 239000003513 alkali Substances 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 3
- 238000006477 desulfuration reaction Methods 0.000 description 3
- 230000023556 desulfurization Effects 0.000 description 3
- 238000001035 drying Methods 0.000 description 3
- 239000000446 fuel Substances 0.000 description 3
- 150000007522 mineralic acids Chemical class 0.000 description 3
- 150000007524 organic acids Chemical class 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 230000001376 precipitating effect Effects 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- ATRRKUHOCOJYRX-UHFFFAOYSA-N Ammonium bicarbonate Chemical compound [NH4+].OC([O-])=O ATRRKUHOCOJYRX-UHFFFAOYSA-N 0.000 description 2
- 229910000013 Ammonium bicarbonate Inorganic materials 0.000 description 2
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N Propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 2
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 description 2
- 238000002441 X-ray diffraction Methods 0.000 description 2
- 229910021536 Zeolite Inorganic materials 0.000 description 2
- 230000004913 activation Effects 0.000 description 2
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 description 2
- 235000012538 ammonium bicarbonate Nutrition 0.000 description 2
- 239000001099 ammonium carbonate Substances 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 2
- 239000004327 boric acid Substances 0.000 description 2
- 239000006227 byproduct Substances 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- HNPSIPDUKPIQMN-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Al]O[Al]=O HNPSIPDUKPIQMN-UHFFFAOYSA-N 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 description 2
- 238000001556 precipitation Methods 0.000 description 2
- 238000010298 pulverizing process Methods 0.000 description 2
- 238000005245 sintering Methods 0.000 description 2
- 239000011973 solid acid Substances 0.000 description 2
- 238000003786 synthesis reaction Methods 0.000 description 2
- 239000013076 target substance Substances 0.000 description 2
- 238000005406 washing Methods 0.000 description 2
- 239000010457 zeolite Substances 0.000 description 2
- JIAARYAFYJHUJI-UHFFFAOYSA-L zinc dichloride Chemical compound [Cl-].[Cl-].[Zn+2] JIAARYAFYJHUJI-UHFFFAOYSA-L 0.000 description 2
- ONDPHDOFVYQSGI-UHFFFAOYSA-N zinc nitrate Chemical compound [Zn+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O ONDPHDOFVYQSGI-UHFFFAOYSA-N 0.000 description 2
- BNGXYYYYKUGPPF-UHFFFAOYSA-M (3-methylphenyl)methyl-triphenylphosphanium;chloride Chemical compound [Cl-].CC1=CC=CC(C[P+](C=2C=CC=CC=2)(C=2C=CC=CC=2)C=2C=CC=CC=2)=C1 BNGXYYYYKUGPPF-UHFFFAOYSA-M 0.000 description 1
- 229910000761 Aluminium amalgam Inorganic materials 0.000 description 1
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 description 1
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- 239000005749 Copper compound Substances 0.000 description 1
- 239000005751 Copper oxide Substances 0.000 description 1
- MXRIRQGCELJRSN-UHFFFAOYSA-N O.O.O.[Al] Chemical compound O.O.O.[Al] MXRIRQGCELJRSN-UHFFFAOYSA-N 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- FMRLDPWIRHBCCC-UHFFFAOYSA-L Zinc carbonate Chemical compound [Zn+2].[O-]C([O-])=O FMRLDPWIRHBCCC-UHFFFAOYSA-L 0.000 description 1
- MGQIWUQTCOJGJU-UHFFFAOYSA-N [AlH3].Cl Chemical compound [AlH3].Cl MGQIWUQTCOJGJU-UHFFFAOYSA-N 0.000 description 1
- ZOIORXHNWRGPMV-UHFFFAOYSA-N acetic acid;zinc Chemical compound [Zn].CC(O)=O.CC(O)=O ZOIORXHNWRGPMV-UHFFFAOYSA-N 0.000 description 1
- HDYRYUINDGQKMC-UHFFFAOYSA-M acetyloxyaluminum;dihydrate Chemical compound O.O.CC(=O)O[Al] HDYRYUINDGQKMC-UHFFFAOYSA-M 0.000 description 1
- DIZPMCHEQGEION-UHFFFAOYSA-H aluminium sulfate (anhydrous) Chemical compound [Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DIZPMCHEQGEION-UHFFFAOYSA-H 0.000 description 1
- 229940009827 aluminum acetate Drugs 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 229910052796 boron Inorganic materials 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 150000001880 copper compounds Chemical class 0.000 description 1
- BICXKAQZWLCDDX-UHFFFAOYSA-N copper dinitrate pentahydrate Chemical compound O.O.O.O.O.[Cu+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O BICXKAQZWLCDDX-UHFFFAOYSA-N 0.000 description 1
- 229910000431 copper oxide Inorganic materials 0.000 description 1
- 229910000365 copper sulfate Inorganic materials 0.000 description 1
- ORTQZVOHEJQUHG-UHFFFAOYSA-L copper(II) chloride Chemical compound Cl[Cu]Cl ORTQZVOHEJQUHG-UHFFFAOYSA-L 0.000 description 1
- XTVVROIMIGLXTD-UHFFFAOYSA-N copper(II) nitrate Chemical compound [Cu+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O XTVVROIMIGLXTD-UHFFFAOYSA-N 0.000 description 1
- ARUVKPQLZAKDPS-UHFFFAOYSA-L copper(II) sulfate Chemical compound [Cu+2].[O-][S+2]([O-])([O-])[O-] ARUVKPQLZAKDPS-UHFFFAOYSA-L 0.000 description 1
- OPQARKPSCNTWTJ-UHFFFAOYSA-L copper(ii) acetate Chemical compound [Cu+2].CC([O-])=O.CC([O-])=O OPQARKPSCNTWTJ-UHFFFAOYSA-L 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 238000006297 dehydration reaction Methods 0.000 description 1
- 238000001514 detection method Methods 0.000 description 1
- 238000004817 gas chromatography Methods 0.000 description 1
- 239000011521 glass Substances 0.000 description 1
- 239000010439 graphite Substances 0.000 description 1
- 229910002804 graphite Inorganic materials 0.000 description 1
- 238000006703 hydration reaction Methods 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- 238000005984 hydrogenation reaction Methods 0.000 description 1
- 238000010335 hydrothermal treatment Methods 0.000 description 1
- 239000003915 liquefied petroleum gas Substances 0.000 description 1
- 150000002736 metal compounds Chemical class 0.000 description 1
- 238000005272 metallurgy Methods 0.000 description 1
- 239000003345 natural gas Substances 0.000 description 1
- 150000002894 organic compounds Chemical class 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- 238000005504 petroleum refining Methods 0.000 description 1
- 229910000027 potassium carbonate Inorganic materials 0.000 description 1
- 238000010248 power generation Methods 0.000 description 1
- 239000001294 propane Substances 0.000 description 1
- 238000006057 reforming reaction Methods 0.000 description 1
- 239000012266 salt solution Substances 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000007493 shaping process Methods 0.000 description 1
- 229910000030 sodium bicarbonate Inorganic materials 0.000 description 1
- 235000017557 sodium bicarbonate Nutrition 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 238000001308 synthesis method Methods 0.000 description 1
- 239000004246 zinc acetate Substances 0.000 description 1
- 239000011667 zinc carbonate Substances 0.000 description 1
- 235000004416 zinc carbonate Nutrition 0.000 description 1
- 229910000010 zinc carbonate Inorganic materials 0.000 description 1
- 239000011592 zinc chloride Substances 0.000 description 1
- 235000005074 zinc chloride Nutrition 0.000 description 1
- 150000003752 zinc compounds Chemical class 0.000 description 1
- NWONKYPBYAMBJT-UHFFFAOYSA-L zinc sulfate Chemical compound [Zn+2].[O-]S([O-])(=O)=O NWONKYPBYAMBJT-UHFFFAOYSA-L 0.000 description 1
- 229910000368 zinc sulfate Inorganic materials 0.000 description 1
- 229960001763 zinc sulfate Drugs 0.000 description 1
Abstract
Description
【０００１】
【発明の属する技術分野】
本発明はジメチルエーテルの水蒸気改質反応に使用される触媒および該反応よる水素含有ガス製造法に関する。
水素ガスはアンモニア合成、各種有機化合物の水素化、石油精製、脱硫等の化学工業用あるいは半導体や冶金の雰囲気ガス、ガラス製造等に広く使用されている。また、最近は自動車等の動力源となる燃料電池用の原料としても注目されており、水素ガス需要の大幅な拡大が期待されている。
【０００２】
【従来の技術】
水素ガスの製造法としては、例えば、ナフサ、天然ガスや石油液化ガス等の炭化水素類の水蒸気改質法が知られている。この方法は原料の脱硫が必要なこと、反応温度が８００〜１０００℃で非常に高いこと等の欠点を有する。
また、メタノールを原料とした水蒸気改質法もよく知られており、脱硫が不要で反応温度が低い等の利点を有し、近年注目され、小規模から大規模までの設備が多数設置されている。
【０００３】
最近、ジメチルエーテルを原料とする水蒸気改質法による水素ガスの製造法が注目されている。ジメチルエーテルはクリーンな燃料として自動車および発電用途として期待されており、常温において約６気圧程度で容易に液化するため、貯蔵や運搬等液化プロパンガスと同等の取り扱いが可能である。
ジメチルエーテルは、現在、メタノールの脱水反応によって製造されており、高価ではあるが、合成ガスからの直接合成法が開発されるに至って、安価に、かつ、大量に供給できる可能性が生じている。
【０００４】
ジメチルエーテルの水蒸気改質反応は（１）式および（２）式の２段反応で進行するものと見られる。
ＣＨ３ＯＣＨ３＋ Ｈ２Ｏ ＝ ２ＣＨ３ＯＨ − ２３．５ｋＪ／ｍｏｌ （１）
ＣＨ３ＯＨ ＋ Ｈ２Ｏ ＝ ＣＯ２ ＋ ３Ｈ２ − ４９．５ｋＪ／ｍｏｌ （２）
また、上記の主反応の他に（３）式のシフト反応や（４）式のメタネーション反応などにより少量の一酸化炭素やメタンが副生する。
ＣＯ２ ＋ Ｈ２＝ ＣＯ ＋ Ｈ２Ｏ − ４１．１７ｋＪ／ｍｏｌ（３）
ＣＯ ＋ ３Ｈ２＝ ＣＨ４＋ Ｈ２Ｏ ＋ ２０６．２ｋＪ／ｍｏｌ（４）
これらの反応により副生した一酸化炭素やメタンは高純度水素に精製する際に除去しにくく、極力少ない方が好ましい。熱力学平衡から、低温ほど、また水蒸気（Ｓ）とジメチルエーテル（Ｄ）のモル比（以下、Ｓ／Ｄ比と称す。）が大きいほど改質ガス中の副生物濃度を低くさせることができる。
ジメチルエーテルの水蒸気改質反応は（２）式のみのメタノール改質反応に比べて化学量論上は２倍量の水素を生成させることが可能であるが、（１）式の水和反応が吸熱反応であるため、より高温での反応条件が必要である。従って、より低温においても高活性を有する触媒であれば、外熱供給システムを小型化することが可能となり、熱効率を上げることができる。
【０００５】
ジメチルエーテルの水蒸気改質反応に使用される触媒としては、例えば、銅、亜鉛、アルミニウムの酸化物を含有する触媒、銅、亜鉛、アルミニウムの酸化物を含有する触媒とゼオライトやシリカ−アルミナの混合触媒、銅触媒とγ−アルミナ、ゼオライト、シリカ−アルミナを物理混合した触媒等が提案されている。しかしながら、従来知られているジメチルエーテルの水蒸気改質用触媒では耐熱性や活性が十分でなく、そのまま反応に使用することができない。
例えば、銅、亜鉛の酸化物触媒と固体酸触媒をある粒径で物理混合する触媒はジメチルエーテル水蒸気改質反応に使用することができるが、この場合、反応熱により触媒成分である銅、亜鉛のシンタリングや触媒粒子の粉化等により、短時間でその活性が低下する（例えば特許文献１参照）。耐熱性を高めるためにアルミニウム酸化物を添加した銅、亜鉛、アルミニウム系触媒が知られているが、この触媒も３５０℃以上の反応環境では耐久性が十分でない（例えば特許文献２参照）。また、銅を固体酸等に担持させた触媒では反応率は高いものの、一酸化炭素や残存メタノール等の副生物濃度が高く、燃料電池用に使用する場合には、生成する一酸化炭素のため、電極が被毒され、電極寿命を短縮させる（例えば特許文献３参照）。
【０００６】
【特許文献１】
米国特許第５，４９８，３７０号明細書
【特許文献２】
特開平９−１１８５０１号公報
【特許文献３】
特開２００１−９６１５９号公報
【０００７】
【発明が解決しようとする課題】
以上、従来技術で述べたように、ジメチルエーテルを水蒸気改質し、水素を製造する場合には、一般に３５０〜４５０℃の反応温度が必要であり、エネルギーコストを考えた場合、より低温での熱供給に対して高活性を示す触媒が求められる。
また、自動車等の動力源となる燃料電池用に水素を製造する場合には、搭載容量等に制限があるために、改質反応器を小型化することが必要であり、ガス空間速度（以下、ＧＨＳＶとする）が高い場合においても、より活性の高い触媒が求められる。
本発明の目的はジメチルエーテルの水蒸気改質において低温域で高活性を有する触媒を開発し、小型装置にて容易に水素含有ガスを製造する方法を提供することである。
【０００８】
【課題を解決するための手段】
本発明者らはジメチルエーテルの水蒸気改質により水素含有ガスを製造する方法における上記課題について鋭意研究した結果、銅および亜鉛を含有する前駆体混合物と、ベーマイトとγ−アルミナを共存させたアルミナ成分またはベーマイトを経てγ−アルミナを形成させたアルミナ成分を混合して調製した触媒が、高活性を有し、しかも耐熱性も有することから高ＧＨＳＶの反応にも好適であることを見い出し、本発明に到達した。
【０００９】
すなわち、本発明は、以下のジメチルエーテル改質用触媒および該触媒を用いた水素含有ガスの製造方法を提供するものである。
（１）銅および亜鉛を含有する前駆体混合物にアルミナ成分を混合して調製するジメチルエーテル改質用触媒において、該アルミナ成分としてベーマイトとγ−アルミナを共存させたアルミナ成分を用いることを特徴とするジメチルエーテル改質用触媒。
（２）銅および亜鉛を含有する前駆体混合物にアルミナ成分を混合して調製するジメチルエーテル改質用触媒において、該アルミナ成分としてベーマイトを経てγ−アルミナを形成させたアルミナ成分を用いることを特徴とするジメチルエーテル改質用触媒。
（３）ベーマイトとγ−アルミナを共存させたアルミナ成分が、ベーマイトを含むアルミナ前駆体を焼成し、γ−アルミナを部分的に形成させたものである上記（１）のジメチルエーテル改質用触媒。
（４）ベーマイトを経てγ−アルミナを共存させたアルミナ成分が、ベーマイトを含むアルミナ前駆体を焼成し、全てγ−アルミナとしたものである上記（２）のジメチルエーテル改質用触媒。
（５）触媒中のアルミナ成分の含有量が２０〜９０重量％である上記（１）〜（４）のいずれかに記載のジメチルエーテル改質用触媒。
（６）アルミナ前駆体の焼成温度が３５０〜７００℃である上記（１）〜（５）のいずれかに記載のジメチルエーテル改質用触媒。
（７）銅および亜鉛を含有する前駆体が、共沈により製造されたものである上記（１）〜（６）のいずれかに記載のジメチルエーテル改質用触媒。
（８）上記（１）〜（７）のいずれかに記載のジメチルエーテル改質用触媒の存在下で、ジメチルエーテルと水蒸気を反応させ、水素を製造することを特徴とする水素含有ガスの製造方法。
【００１０】
【発明の実施の形態】
本発明のジメチルエーテル改質用触媒は、銅および亜鉛を含有する前駆体混合物とベーマイトとγ−アルミナを共存させたアルミナ成分またはベーマイトを経てγ−アルミナを形成させたアルミナ成分を混合して調製する。
この銅および亜鉛を含有する前駆体混合物は、各金属成分を含有する沈殿物を含むスラリー状混合物である。各金属成分を含有する沈殿物は、当該金属を含有する化合物を処理することで得られ、原料としては、この沈殿物を焼成したときに酸化物に変化し得る金属化合物が用いられる。
【００１１】
銅化合物としては、例えば酢酸銅等の有機酸の水溶性塩、塩化銅、硫酸銅、硝酸銅等の無機酸の水溶性塩等が使用できる。亜鉛化合物としては、例えば酢酸亜鉛等の有機酸の水溶性塩、塩化亜鉛、硫酸亜鉛、硝酸亜鉛等の無機酸の水溶性塩や酸化亜鉛等が使用できる。
また、銅および亜鉛を含有する前駆体混合物には焼成したときに酸化物に変化し得るアルミニウム化合物を共存させることも可能であり、その場合のアルミニウム化合物としては、例えば酢酸アルミニウム等の有機酸の水溶性塩、塩酸アルミニウム、硫酸アルミニウム、硝酸アルミニウム等の無機酸の水溶性塩等が使用できる。
【００１２】
これらの金属塩の水溶液に沈殿剤を作用させることにより、当該金属を含有する沈殿物を得ることができる。沈殿剤には、水酸化ナトリウム、水酸化カリウム、炭酸ナトリウム、炭酸カリウム、炭酸水素ナトリウム等の水溶性アルカリ化合物が用いられる。なお、酸化亜鉛を使用する際には、水中に分散させ、炭酸ガスと接触させることにより、炭酸亜鉛の沈殿物を得ることができる。また、これらの沈殿調製時にホウ素化合物を共存させると調製後の触媒の活性が向上するのでより好ましい。ホウ素化合物としては、例えばホウ酸が好適に使用できる。
【００１３】
沈殿調製時の金属塩水溶液の濃度は０．２〜３モル／リットル、好ましくは０．５〜２モル／リットルである。金属塩に対する沈殿剤の量は、化学等量の１〜２倍、好ましくは１．１〜１．６倍である。また、沈殿調整時の温度は２０〜９０℃、好ましくは３５〜８５℃である。本発明による触媒の組成は銅／亜鉛の原子比で０．２〜１２、好ましくは０．５〜１０である。銅および亜鉛の金属としての組成は銅１５〜６０重量％、亜鉛１５〜４０重量％の範囲が好ましい。また、アルミニウム化合物、ホウ素化合物を共存させる場合は、アルミニウムとして５〜１５重量％、ホウ素として０．１〜３重量％である。
【００１４】
銅および亜鉛を含有する前駆体混合物は、（１）上述の方法で得られた沈殿物を混合する、（２）ある金属の沈殿物存在下で他の金属を沈殿させる、（３）２種の金属を同時に沈殿させる等の各種方法で得られる。特に本発明では、銅および亜鉛の沈殿物を含有するスラリーとアルミニウムの沈殿物を含有するスラリーを別途調製し、これらのスラリーを混合することにより、触媒成分が緊密に混合され、優れた触媒性能を与えるので好ましい。銅および亜鉛の沈殿物を含有するスラリーは、共沈殿法で調製されたものが好ましく、例えば銅および亜鉛を含む水溶液と炭酸アルカリのような沈殿剤で沈殿させる方法、銅の沈殿スラリーに酸化亜鉛を分散させ、炭酸ガスにより炭酸化する方法等で調製することができる。ホウ素化合物の共存下で、銅の無機酸塩水溶液とアルカリ沈殿剤、および酸化亜鉛と炭酸ガスを用いて調製されたものがより好ましい。
【００１５】
このようにして得られた混合スラリーは通常純水等で洗浄する。原料に硫酸塩を使用した場合には希薄アルカリ水溶液等で洗浄することが好ましい。以上の方法により調製して得られた洗浄後の混合スラリーは、乾燥し、焼成する。乾燥温度は５０〜１５０℃で、焼成は空気中１８０℃〜５００℃、好ましくは２００〜４００℃で行われる。このようにして得られた乾燥粉あるいは焼成粉は粉砕し、ベーマイトとγ−アルミナを共存させたアルミナ成分またはベーマイトを経てγ−アルミナを形成させたアルミナ成分の粉末とよく混合させる。アルミナ成分と乾燥粉とを混合した場合はその後、焼成する。また、混合スラリーとアルミナ成分を混合後、乾燥および焼成してもよい。
【００１６】
銅および亜鉛を含有する前駆体混合物と混合するアルミナ成分は、アルミニウムの水酸化物の一種であるベーマイト［ｂｏｅｈｍｉｔｅ、α−ＡｌＯ（ＯＨ）］を形成後、焼成した、ベーマイトとγ−アルミナと共存させたアルミナ成分、またはγ−アルミナを形成させたアルミナ成分を用いることができる。焼成条件は調製方法、焼成装置により多少差があるが、概ね３５０〜７００℃の範囲であり、４００〜６００℃が特に好ましい。ベーマイトは水酸化アルミニウムの水中あるいは弱塩基性水溶液中、１５０〜３００℃での水熱処理、アルミニウムアマルガムの沸騰水による酸化などで得られることが知られている。また、市販のアルミナゾルなどを乾燥させて形成することができる。触媒中のアルミナ成分量は２０〜９０重量％、好ましくは２５〜８０重量％である。混合スラリーの場合も前記に準ずる。このようにして得られた焼成粉は大きさを揃えて錠剤成型し、粒径を揃えて粉砕する等して、使用することができる。
【００１７】
ベーマイトとγ−アルミナは、例えばＸ線回折装置により同定することができる。具体的にはＸ線回折ピークを測定し、既存の結晶構造データベースとの照合により実施する。最も一般的なデータベースはＪＣＰＤＳ Ｐｏｗｄｅｒ Ｄｉｆｆｒａｃｔｉｏｎ Ｆｉｌｅ（ＰＤＦ：通称ＡＳＴＭカード）であり、今回用いたデータカードはベーマイトが２１−１３０７、γ―アルミナが１０−０４２５である。回折ピークはＡＳＴＭカードにｄ値（Å：オングストローム）と相対強度Ｉ／Ｉ１、面指数（逆格子空間面の帰属）が記載されており、測定に用いたＸ線源の波長λ（例えばＣｕＫα１ではλ＝１．５４０５６Å）と回折の条件式（ブラッグの式）２ｄｓｉｎθ＝ｎλの関係より、回折角θからｄを算出し、ＡＳＴＭカードのｄ−Ｉ／Ｉ１の関係が一致すれば、測定物質とＡＳＴＭカードに記載されている化合物が同じと判断される。場合によっては相対強度が完全に一致せず順番がかわることもあるが、記載されているピークの相対強度比が大きい方（約３０％以上）のｄ値が一致し、その他の測定ピークのｄ値が確認できれば、同一成分が存在するとみなすことができる。なお、Ｘ線回析法の性質上、目的物質の存在量を定量的に計測することは難しいが、単結晶などの例においては０．１〜１ｗｔ％程度存在すれば検出されるものが多いとされており、ベーマイトとγ−アルミナについてもほぼ同様の検出感度にあるものと思われる。
【００１８】
触媒の使用にあたってはジメチルエーテルと水蒸気を反応させる水蒸気改質反応の場合、例えば水素、一酸化炭素含有ガスによって活性化処理を行っても良いし、活性化処理をすることなく、反応に供することもできる。
ジメチルエーテルと水蒸気を反応させて水素含有ガスを製造する際の水蒸気／ジメチルエーテル比（Ｓ／Ｄ）は３〜１０、好ましくは４〜６である。反応温度は１５０〜４００℃、好ましくは２００〜３５０℃で、圧力は常圧が好ましい。単位触媒当たりの水蒸気およびジメチルエーテルのガス空間速度（ＧＨＳＶ）は、３００〜１５０００（１／ｈ）、好ましくは５００〜６０００（１／ｈ）である。
【００１９】
【実施例】
次に、本発明の実施例により、さらに詳細に説明するが、本発明は、これらの例よってなんら限定されるものではない。
以下に実施例および比較例において、触媒活性の評価は次のように行った。すなわち、固定床流通反応装置の反応管に各触媒を２ｍｌ充填し、触媒層にスチーム／ジメチルエーテル比（Ｓ／Ｄ）５／１、ＧＨＳＶ６０００／ｈで供給し、常圧、温度２６０〜４３０℃で反応を行った。反応後のガスはガスクロマトグラフィーにより分析し、ジメチルエーテル反応率を算出した。
なお、触媒活性の評価結果を示す第１表において、出口ガス組成中のＣＨ４、ＣＯ、Ｈ２以外の主な成分はジメチルエーテルとＣＯ２であり、該組成は水蒸気を除く成分のモル％である。
【００２０】
実施例１
炭酸水素アンモニウム１４０．４ｇを１１８６ｍｌのイオン交換水と共に５リットルの丸底フラスコに入れ溶解し、４０℃に保持した。また、硝酸銅（５水塩）１９５ｇおよびホウ酸１８．８ｇをイオン交換水１２９０ｍｌに溶解し、４０℃とした溶液を前述の炭酸水素アンモニウム溶液へ注加した。続いて同溶液に、酸化亜鉛４３．８ｇをイオン交換水５００ｍｌに分散したスラリーを加え、直ちに炭酸ガスを６Ｌ／ｈの流速で吹き込んだ。１時間後、８０℃へ昇温し、３０分保持した。炭酸ガスは２時間で停止し、６０℃まで冷却した。濾過、洗浄後、濾別した沈殿物を８０℃で乾燥、３８０℃で焼成し、更にメノウ鉢で粉砕、３０メッシュ以下のＣｕ／Ｚｎ焼成粉を得た。
別途、アルミナゾル（日産化学工業（株）製、品番５２０）を８０℃で乾燥し、このアルミナ成分をＸ線回折装置（（株）マック・サイエンス製Ｍ１８ＸＨＦ２２−ＳＲＡ）で成分形態を確認したところ、ベーマイトと同定された。更に４２０℃で焼成し、このアルミナ成分をＸ線回折装置で成分形態を確認したところ、ベーマイトとγ−アルミナが同定され、その他の成分は検出されなかった。
Ｃｕ／Ｚｎ焼成粉１２ｇにアルミナ成分を２８ｇ加え、更にグラファイトを１．２ｇ加え、乾式でよく混合し、３ｍｍφ×５ｍｍｈの円柱形状に打錠成型したものを２０〜３５メッシュに粉砕、整粒した。このようにしてアルミナ成分がベーマイトとγ−アルミナからなる、銅、亜鉛、アルミニウムを主成分とする触媒Ａを得た。触媒活性の評価結果を第１表に示す。
【００２１】
実施例２
実施例１と同様の手法でアルミナゾル（日産化学工業（株）製、品番５２０）を８０℃で乾燥し、更に６００℃で焼成後、このアルミナ成分をＸ線回折装置で成分形態を確認したところ、γ−アルミナが同定され、ベーマイトおよびその他の成分は検出されなかった。このアルミナ成分を用いた以外は、実施例１と同じ方法を実施し、アルミナ成分がγ−アルミナのみからなる、銅、亜鉛、アルミニウムを主成分とする触媒Ｂを得た。触媒活性の評価結果を第１表に示す。
【００２２】
実施例３
Ｘ線回折装置でベーマイトとγ−アルミナの２成分からなることを確認したアルミナ粉（比表面積：２３０ｍ２／ｇ）２０ｇとＣｕ／Ｚｎ焼成粉２０ｇを用いた以外は実施例１と同様な方法を実施し、触媒Ｃを得た。触媒活性の評価結果を第１表に示す。
【００２３】
実施例４
実施例３で用いたアルミナ粉（比表面積：２３０ｍ２／ｇ）を６００℃で焼成し、Ｘ線回折装置で成分形態を確認したところ、γ−アルミナが同定され、ベーマイトおよびその他の成分は検出されなかった。このγ−アルミナのみからなるアルミナ粉２８ｇとＣｕ／Ｚｎ焼成粉１２ｇを用いた以外は実施例１と同様な方法を実施し、触媒Ｄを得た。触媒活性の評価結果を第１表に示す。
【００２４】
比較例１
実施例１と同様の手法でアルミナゾル（日産化学工業（株）製、品番５２０）を８０℃で乾燥し、更に３００℃で焼成後、このアルミナ成分をＸ線回折装置で成分形態を確認したところ、ベーマイトが同定され、γ−アルミナおよびその他の成分は検出されなかった。このベーマイトのみからなるアルミナ成分を用いた以外は、実施例１と同じ方法を実施し、触媒Ｅを得た。
触媒活性の評価結果を第１表に示す。ジメチルエーテル反応率が１００％となる温度は４２３℃であり、各実施例と比較して高温となり、ＣＯ温度が高いことが分かる。
【００２５】
比較例２
別のアルミナゾル（日産化学工業（株）製、品番２００）を８０℃で乾燥し、更に３００℃焼成後、このアルミナ成分をＸ線回折装置で成分形態を確認したところ、特徴ある回折ピークは認められず、無定形アルミナと同定された。このアルミナ成分を更に６００℃で焼成後、Ｘ線回折装置で成分形態を確認したところ、γ−アルミナが同定され、その他の成分は検出されなかった。このγ−アルミナのみからなるアルミナ成分を用いた以外は、実施例１と同じ方法を実施し、触媒Ｆを得た。触媒活性の評価結果を第１表に示す。
【００２６】
【表１】
【発明の効果】
本発明のジメチルエーテル改質用触媒は、低温で高活性を有し、高いガス空間速度（ＧＨＳＶ）で使用できることから、ジメチルエーテルの水蒸気改質により、小型装置で、効率よく、水素含有含有ガスを製造することができる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a catalyst used for a steam reforming reaction of dimethyl ether and a method for producing a hydrogen-containing gas by the reaction.
Hydrogen gas is widely used for chemical industry such as ammonia synthesis, hydrogenation of various organic compounds, petroleum refining, desulfurization, etc., atmosphere gas for semiconductors and metallurgy, glass production, and the like. Further, recently, it has been drawing attention as a raw material for a fuel cell as a power source of an automobile or the like, and a large increase in demand for hydrogen gas is expected.
[0002]
[Prior art]
As a method for producing hydrogen gas, for example, a steam reforming method for hydrocarbons such as naphtha, natural gas, and liquefied petroleum gas is known. This method has disadvantages such as the necessity of desulfurization of the raw material and the fact that the reaction temperature is very high at 800 to 1000 ° C.
In addition, a steam reforming method using methanol as a raw material is also well known, and has advantages such as no need for desulfurization and a low reaction temperature. In recent years, attention has been paid to a large number of small- to large-scale facilities installed. I have.
[0003]
Recently, a method for producing hydrogen gas by a steam reforming method using dimethyl ether as a raw material has attracted attention. Dimethyl ether is expected to be used as a clean fuel in automobiles and power generation applications. Since it is easily liquefied at about 6 atm at room temperature, it can be handled in the same manner as liquefied propane gas such as storage and transportation.
Dimethyl ether is currently produced by a dehydration reaction of methanol and is expensive, but the possibility of supplying it inexpensively and in large quantities has arisen as a direct synthesis method from synthesis gas has been developed.
[0004]
It is considered that the steam reforming reaction of dimethyl ether proceeds in a two-stage reaction of the formulas (1) and (2).
CH 3 OCH 3 + H 2 O = 2CH 3 OH - 23.5kJ / mol (1)
CH 3 OH + H 2 O = CO 2 + 3H 2 − 49.5 kJ / mol (2)
In addition to the main reaction, a small amount of carbon monoxide and methane are by-produced by the shift reaction of the formula (3) or the methanation reaction of the formula (4).
CO 2 + H 2 = CO + H 2 O - 41.17kJ / mol (3)
CO + 3H 2 = CH 4 + H 2 O + 206.2kJ / mol (4)
Carbon monoxide and methane by-produced by these reactions are difficult to remove when purifying to high-purity hydrogen, and it is preferable that they are minimized. From thermodynamic equilibrium, the concentration of by-products in the reformed gas can be reduced as the temperature decreases and as the molar ratio of steam (S) to dimethyl ether (D) (hereinafter, referred to as S / D ratio) increases.
The steam reforming reaction of dimethyl ether can generate twice as much stoichiometrically hydrogen as the methanol reforming reaction of the formula (2) alone, but the hydration reaction of the formula (1) is endothermic. Because of the reaction, higher temperature reaction conditions are required. Therefore, if the catalyst has high activity even at a lower temperature, the external heat supply system can be reduced in size, and the thermal efficiency can be increased.
[0005]
Examples of the catalyst used in the steam reforming reaction of dimethyl ether include, for example, a catalyst containing an oxide of copper, zinc, and aluminum, a catalyst containing an oxide of copper, zinc, and aluminum, and a mixed catalyst of zeolite and silica-alumina. , A catalyst obtained by physically mixing a copper catalyst with γ-alumina, zeolite, and silica-alumina has been proposed. However, the conventionally known catalyst for steam reforming of dimethyl ether has insufficient heat resistance and activity and cannot be used for the reaction as it is.
For example, a catalyst in which a copper and zinc oxide catalyst and a solid acid catalyst are physically mixed at a certain particle size can be used for a dimethyl ether steam reforming reaction. Its activity is reduced in a short time due to sintering, pulverization of catalyst particles, and the like (for example, see Patent Document 1). Copper, zinc, and aluminum-based catalysts to which aluminum oxide is added to enhance heat resistance are known, but these catalysts also have insufficient durability in a reaction environment at 350 ° C. or higher (for example, see Patent Document 2). In addition, although the reaction rate is high in a catalyst in which copper is supported on a solid acid or the like, the concentration of by-products such as carbon monoxide and residual methanol is high. In addition, the electrode is poisoned, and the life of the electrode is shortened (for example, see Patent Document 3).
[0006]
[Patent Document 1]
US Patent No. 5,498,370 [Patent Document 2]
Japanese Patent Application Laid-Open No. Hei 9-118501 [Patent Document 3]
JP 2001-96159 A
[Problems to be solved by the invention]
As described above, in the case of producing hydrogen by reforming dimethyl ether by steam as described in the prior art, a reaction temperature of 350 to 450 ° C. is generally required. There is a need for a catalyst that exhibits high activity for feed.
In addition, when producing hydrogen for a fuel cell as a power source of an automobile or the like, it is necessary to reduce the size of the reforming reactor due to limitations in the mounted capacity and the like, and the gas space velocity (hereinafter, referred to as the , GHSV), a catalyst with higher activity is required.
An object of the present invention is to develop a catalyst having high activity in a low temperature region in steam reforming of dimethyl ether, and to provide a method for easily producing a hydrogen-containing gas with a small apparatus.
[0008]
[Means for Solving the Problems]
The present inventors have conducted intensive studies on the above problems in a method for producing a hydrogen-containing gas by steam reforming of dimethyl ether, and as a result, a precursor mixture containing copper and zinc, an alumina component in which boehmite and γ-alumina coexisted or It has been found that a catalyst prepared by mixing an alumina component that has formed γ-alumina via boehmite has high activity and is also suitable for high GHSV reactions because it has heat resistance. Reached.
[0009]
That is, the present invention provides the following dimethyl ether reforming catalyst and a method for producing a hydrogen-containing gas using the catalyst.
(1) A dimethyl ether reforming catalyst prepared by mixing an alumina component with a precursor mixture containing copper and zinc, wherein an alumina component in which boehmite and γ-alumina coexist is used as the alumina component. Dimethyl ether reforming catalyst.
(2) A dimethyl ether reforming catalyst prepared by mixing an alumina component with a precursor mixture containing copper and zinc, wherein an alumina component obtained by forming γ-alumina through boehmite is used as the alumina component. Dimethyl ether reforming catalyst.
(3) The dimethyl ether reforming catalyst according to (1), wherein the alumina component in which boehmite and γ-alumina coexist is obtained by calcining an alumina precursor containing boehmite to partially form γ-alumina.
(4) The dimethyl ether reforming catalyst according to the above (2), wherein the alumina component in which γ-alumina coexists via boehmite is obtained by calcining an alumina precursor containing boehmite to obtain all γ-alumina.
(5) The dimethyl ether reforming catalyst according to any one of the above (1) to (4), wherein the content of the alumina component in the catalyst is 20 to 90% by weight.
(6) The dimethyl ether reforming catalyst according to any one of the above (1) to (5), wherein the firing temperature of the alumina precursor is 350 to 700 ° C.
(7) The dimethyl ether reforming catalyst according to any one of the above (1) to (6), wherein the precursor containing copper and zinc is produced by coprecipitation.
(8) A method for producing hydrogen-containing gas, comprising reacting dimethyl ether with steam in the presence of the dimethyl ether reforming catalyst according to any one of (1) to (7) to produce hydrogen.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
The catalyst for reforming dimethyl ether of the present invention is prepared by mixing a precursor mixture containing copper and zinc and an alumina component in which boehmite and γ-alumina coexist or an alumina component in which γ-alumina is formed through boehmite. .
The precursor mixture containing copper and zinc is a slurry mixture containing a precipitate containing each metal component. A precipitate containing each metal component is obtained by treating a compound containing the metal, and as a raw material, a metal compound that can be converted to an oxide when the precipitate is fired is used.
[0011]
As the copper compound, for example, a water-soluble salt of an organic acid such as copper acetate, a water-soluble salt of an inorganic acid such as copper chloride, copper sulfate, and copper nitrate can be used. Examples of the zinc compound include a water-soluble salt of an organic acid such as zinc acetate, a water-soluble salt of an inorganic acid such as zinc chloride, zinc sulfate, and zinc nitrate, and zinc oxide.
Further, it is also possible to coexist an aluminum compound that can be converted to an oxide when calcined in the precursor mixture containing copper and zinc, and in this case, as the aluminum compound, for example, an organic acid such as aluminum acetate can be used. Water-soluble salts, water-soluble salts of inorganic acids such as aluminum hydrochloride, aluminum sulfate and aluminum nitrate can be used.
[0012]
By causing a precipitant to act on an aqueous solution of these metal salts, a precipitate containing the metal can be obtained. As the precipitant, a water-soluble alkali compound such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, and sodium hydrogen carbonate is used. When using zinc oxide, a precipitate of zinc carbonate can be obtained by dispersing it in water and bringing it into contact with carbon dioxide gas. It is more preferable to coexist a boron compound during the preparation of these precipitates, since the activity of the catalyst after the preparation is improved. As the boron compound, for example, boric acid can be suitably used.
[0013]
The concentration of the aqueous metal salt solution at the time of preparing the precipitate is 0.2 to 3 mol / l, preferably 0.5 to 2 mol / l. The amount of the precipitant relative to the metal salt is 1-2 times, preferably 1.1-1.6 times, the chemical equivalent. The temperature at the time of adjusting the precipitation is 20 to 90 ° C, preferably 35 to 85 ° C. The composition of the catalyst according to the invention is in the atomic ratio copper / zinc between 0.2 and 12, preferably between 0.5 and 10. The composition of copper and zinc as metals is preferably in the range of 15 to 60% by weight of copper and 15 to 40% by weight of zinc. When an aluminum compound and a boron compound coexist, the content is 5 to 15% by weight as aluminum and 0.1 to 3% by weight as boron.
[0014]
The precursor mixture containing copper and zinc is (1) mixing the precipitate obtained by the above-described method, (2) precipitating another metal in the presence of a certain metal precipitate, and (3) two types. And various methods such as simultaneous precipitation of metals. In particular, in the present invention, a slurry containing a precipitate of copper and zinc and a slurry containing a precipitate of aluminum are separately prepared, and by mixing these slurries, the catalyst components are mixed intimately, resulting in excellent catalyst performance. Is preferred. The slurry containing the precipitate of copper and zinc is preferably prepared by a co-precipitation method, for example, a method of precipitating with an aqueous solution containing copper and zinc and a precipitant such as alkali carbonate, and a method of precipitating a copper slurry with zinc oxide. Can be dispersed and carbonized with carbon dioxide gas. Those prepared using an aqueous solution of an inorganic acid salt of copper and an alkali precipitant, and zinc oxide and carbon dioxide in the presence of a boron compound are more preferable.
[0015]
The mixed slurry thus obtained is usually washed with pure water or the like. When a sulfate is used as a raw material, it is preferable to wash with a diluted alkaline aqueous solution or the like. The mixed slurry after washing obtained and prepared by the above method is dried and fired. The drying temperature is 50 to 150 ° C, and the calcination is performed in air at 180 to 500 ° C, preferably 200 to 400 ° C. The dry powder or the calcined powder thus obtained is pulverized and mixed well with an alumina component in which boehmite and γ-alumina coexist or an alumina component in which γ-alumina is formed through boehmite. When the alumina component and the dry powder are mixed, firing is performed thereafter. After the mixed slurry and the alumina component are mixed, drying and firing may be performed.
[0016]
The alumina component mixed with the precursor mixture containing copper and zinc forms boehmite [α-AlO (OH)], which is a kind of aluminum hydroxide, and is calcined, and coexists with boehmite and γ-alumina. Alumina component formed or alumina component formed with γ-alumina can be used. The firing conditions vary somewhat depending on the preparation method and firing device, but are generally in the range of 350 to 700 ° C, and particularly preferably 400 to 600 ° C. It is known that boehmite can be obtained by hydrothermal treatment at 150 to 300 ° C. in water of aluminum hydroxide or in a weakly basic aqueous solution, or oxidation of aluminum amalgam by boiling water. Alternatively, it can be formed by drying a commercially available alumina sol or the like. The amount of the alumina component in the catalyst is 20 to 90% by weight, preferably 25 to 80% by weight. The same applies to the case of a mixed slurry. The calcined powder obtained in this way can be used by, for example, tablet-shaping with uniform size and pulverizing with uniform particle size.
[0017]
Boehmite and γ-alumina can be identified by, for example, an X-ray diffractometer. Specifically, the X-ray diffraction peak is measured, and the comparison is performed with an existing crystal structure database. The most common database is JCPDS Powder Diffraction File (PDF: commonly called ASTM card), and the data card used this time is 21-1307 for boehmite and 10-0425 for γ-alumina. As for the diffraction peak, d value (Å: Angstroms), relative intensity I / I 1 , and plane index (attribution of reciprocal lattice space) are described on the ASTM card, and the wavelength λ (for example, CuKα1) of the X-ray source used for measurement Λ = 1.40556 °) and the conditional expression for diffraction (Bragg's equation) 2 ds is calculated from the diffraction angle θ from the relation of θ = nλ, and if the relation of d−I / I 1 of the ASTM card matches, the measurement is performed. The substance and the compound described on the ASTM card are determined to be the same. In some cases, the relative intensities do not completely match, and the order may be changed. However, the d value of the larger relative intensity ratio (about 30% or more) of the described peaks matches, and the d values of the other measured peaks match. If the value can be confirmed, it can be considered that the same component exists. Note that it is difficult to quantitatively measure the amount of the target substance due to the nature of the X-ray diffraction method. However, in the case of a single crystal or the like, it is often detected that the target substance is present at about 0.1 to 1 wt%. It seems that boehmite and γ-alumina have almost the same detection sensitivity.
[0018]
When using a catalyst, in the case of a steam reforming reaction in which dimethyl ether is reacted with steam, for example, an activation treatment may be performed using hydrogen or a gas containing carbon monoxide, or the reaction may be performed without performing the activation treatment. it can.
The ratio of steam / dimethyl ether (S / D) when producing hydrogen-containing gas by reacting dimethyl ether and steam is 3 to 10, preferably 4 to 6. The reaction temperature is 150 to 400 ° C, preferably 200 to 350 ° C, and the pressure is preferably normal pressure. The gas hourly space velocity (GHSV) of steam and dimethyl ether per unit catalyst is 300 to 15000 (1 / h), preferably 500 to 6000 (1 / h).
[0019]
【Example】
Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
Hereinafter, in Examples and Comparative Examples, evaluation of catalyst activity was performed as follows. That is, 2 ml of each catalyst was filled in a reaction tube of a fixed bed flow reactor, and a steam / dimethyl ether ratio (S / D) of 5/1 and GHSV of 6000 / h were supplied to the catalyst layer at normal pressure and a temperature of 260 to 430 ° C. The reaction was performed. The gas after the reaction was analyzed by gas chromatography to calculate the dimethyl ether conversion.
In Table 1 showing the evaluation results of the catalytic activity, the main components other than CH 4 , CO, and H 2 in the outlet gas composition were dimethyl ether and CO 2 , and the composition was represented by mol% of the components excluding steam. is there.
[0020]
Example 1
140.4 g of ammonium bicarbonate was dissolved in a 5 liter round bottom flask together with 1186 ml of ion-exchanged water and kept at 40 ° C. Further, 195 g of copper nitrate (pentahydrate) and 18.8 g of boric acid were dissolved in 1290 ml of ion-exchanged water, and a solution at 40 ° C. was poured into the above-mentioned ammonium hydrogen carbonate solution. Subsequently, a slurry in which 43.8 g of zinc oxide was dispersed in 500 ml of ion-exchanged water was added to the solution, and carbon dioxide gas was blown immediately at a flow rate of 6 L / h. After one hour, the temperature was raised to 80 ° C. and maintained for 30 minutes. Carbon dioxide was stopped in 2 hours and cooled to 60 ° C. After filtration and washing, the precipitate separated by filtration was dried at 80 ° C., calcined at 380 ° C., and further pulverized in an agate bowl to obtain a baked Cu / Zn powder of 30 mesh or less.
Separately, alumina sol (manufactured by Nissan Chemical Industry Co., Ltd., product number 520) was dried at 80 ° C., and the form of the alumina component was confirmed using an X-ray diffractometer (M18XHF 22 -SRA manufactured by Mac Science). , Identified as boehmite. Further calcination was carried out at 420 ° C., and the form of the alumina component was confirmed with an X-ray diffractometer. As a result, boehmite and γ-alumina were identified, and no other components were detected.
28 g of an alumina component was added to 12 g of the baked Cu / Zn powder, 1.2 g of graphite was further added, and the mixture was thoroughly mixed in a dry system, and the mixture was tabletted into a 3 mmφ × 5 mmh cylindrical shape, pulverized to 20 to 35 mesh and sized. . In this way, a catalyst A containing alumina, boehmite and γ-alumina and containing copper, zinc and aluminum as main components was obtained. Table 1 shows the evaluation results of the catalyst activities.
[0021]
Example 2
Alumina sol (Nissan Chemical Industry Co., Ltd., product number 520) was dried at 80 ° C. in the same manner as in Example 1, fired at 600 ° C., and the form of the alumina component was confirmed with an X-ray diffractometer. , Γ-alumina were identified and no boehmite and other components were detected. Except that this alumina component was used, the same method as in Example 1 was performed to obtain a catalyst B containing alumina, γ-alumina alone, and containing copper, zinc, and aluminum as main components. Table 1 shows the evaluation results of the catalyst activities.
[0022]
Example 3
A method similar to that of Example 1 except that 20 g of alumina powder (specific surface area: 230 m 2 / g) and 20 g of Cu / Zn fired powder were confirmed to be composed of two components of boehmite and γ-alumina by an X-ray diffractometer. Was carried out to obtain a catalyst C. Table 1 shows the evaluation results of the catalyst activities.
[0023]
Example 4
The alumina powder (specific surface area: 230 m 2 / g) used in Example 3 was calcined at 600 ° C. and the component form was confirmed by an X-ray diffractometer. As a result, γ-alumina was identified, and boehmite and other components were detected. Was not done. Catalyst D was obtained in the same manner as in Example 1 except that 28 g of the alumina powder consisting of only γ-alumina and 12 g of the calcined Cu / Zn powder were used. Table 1 shows the evaluation results of the catalyst activities.
[0024]
Comparative Example 1
Alumina sol (Nissan Chemical Industry Co., Ltd., product number 520) was dried at 80 ° C. in the same manner as in Example 1, and calcined at 300 ° C., and the alumina morphology was confirmed by X-ray diffractometer. , Boehmite was identified, and γ-alumina and other components were not detected. Catalyst E was obtained in the same manner as in Example 1 except that the alumina component consisting of only boehmite was used.
Table 1 shows the evaluation results of the catalyst activities. The temperature at which the dimethyl ether conversion reaches 100% is 423 ° C., which is higher than in each of the examples, indicating that the CO temperature is higher.
[0025]
Comparative Example 2
Another alumina sol (manufactured by Nissan Chemical Industry Co., Ltd., product number 200) was dried at 80 ° C. and calcined at 300 ° C., and after confirming the form of this alumina component with an X-ray diffractometer, a characteristic diffraction peak was observed. It was identified as amorphous alumina. After further sintering the alumina component at 600 ° C., the component form was confirmed by an X-ray diffractometer. As a result, γ-alumina was identified and no other component was detected. Catalyst F was obtained in the same manner as in Example 1, except that the alumina component consisting of only γ-alumina was used. Table 1 shows the evaluation results of the catalyst activities.
[0026]
[Table 1]
【The invention's effect】
Since the catalyst for reforming dimethyl ether of the present invention has high activity at low temperatures and can be used at a high gas space velocity (GHSV), it is possible to efficiently produce a hydrogen-containing gas with a small apparatus by using steam reforming of dimethyl ether. can do.
Claims (8)
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2007091513A (en) * | 2005-09-28 | 2007-04-12 | Toshiba Corp | Hydrogen generator and fuel cell system |
| JP2007222748A (en) * | 2006-02-22 | 2007-09-06 | Osaka Gas Co Ltd | Steam reforming catalyst for reforming dimethylether and method for preparing hydrogen-containing gas using the same |
| KR100810739B1 (en) | 2006-07-31 | 2008-03-06 | 한국화학연구원 | Catalyst for methanol and dimethyl ether synthesis from syngas and preparation method thereof |
| JP2008296076A (en) * | 2007-05-29 | 2008-12-11 | Mitsubishi Gas Chem Co Inc | Catalyst for reforming dimethyl ether, method for manufacturing the catalyst and method for producing hydrogen-containing gas |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| JP2007091513A (en) * | 2005-09-28 | 2007-04-12 | Toshiba Corp | Hydrogen generator and fuel cell system |
| JP2007222748A (en) * | 2006-02-22 | 2007-09-06 | Osaka Gas Co Ltd | Steam reforming catalyst for reforming dimethylether and method for preparing hydrogen-containing gas using the same |
| KR100810739B1 (en) | 2006-07-31 | 2008-03-06 | 한국화학연구원 | Catalyst for methanol and dimethyl ether synthesis from syngas and preparation method thereof |
| JP2008296076A (en) * | 2007-05-29 | 2008-12-11 | Mitsubishi Gas Chem Co Inc | Catalyst for reforming dimethyl ether, method for manufacturing the catalyst and method for producing hydrogen-containing gas |
| CN101927158A (en) * | 2010-07-12 | 2010-12-29 | 中国日用化学工业研究院 | Preparation method of nano ZnO/gamma-Al2O3 composite photocatalyst |
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