CN113045376A - Method and device for purifying methanol-to-olefin purified water by fluidized bed - Google Patents
Method and device for purifying methanol-to-olefin purified water by fluidized bed Download PDFInfo
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 195
- 239000008213 purified water Substances 0.000 title claims abstract description 75
- 238000000034 method Methods 0.000 title claims abstract description 56
- 238000005406 washing Methods 0.000 claims abstract description 71
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- 238000000926 separation method Methods 0.000 claims abstract description 64
- 238000010791 quenching Methods 0.000 claims abstract description 60
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims abstract description 54
- 230000000171 quenching effect Effects 0.000 claims abstract description 41
- 238000009835 boiling Methods 0.000 claims abstract description 36
- 239000000843 powder Substances 0.000 claims abstract description 27
- 238000000746 purification Methods 0.000 claims abstract description 17
- 238000004064 recycling Methods 0.000 claims abstract description 16
- 238000001816 cooling Methods 0.000 claims abstract description 14
- 238000007599 discharging Methods 0.000 claims abstract description 12
- 239000002002 slurry Substances 0.000 claims abstract description 5
- 239000002245 particle Substances 0.000 claims description 69
- 239000007789 gas Substances 0.000 claims description 33
- 229930195733 hydrocarbon Natural products 0.000 claims description 31
- 150000002430 hydrocarbons Chemical class 0.000 claims description 31
- 239000000126 substance Substances 0.000 claims description 23
- 239000004215 Carbon black (E152) Substances 0.000 claims description 20
- 239000007787 solid Substances 0.000 claims description 18
- 230000008929 regeneration Effects 0.000 claims description 17
- 238000011069 regeneration method Methods 0.000 claims description 17
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 16
- 230000008569 process Effects 0.000 claims description 14
- 238000010992 reflux Methods 0.000 claims description 11
- 239000010865 sewage Substances 0.000 claims description 10
- 229910052757 nitrogen Inorganic materials 0.000 claims description 8
- 239000002994 raw material Substances 0.000 claims description 6
- 238000011084 recovery Methods 0.000 claims description 6
- 238000006243 chemical reaction Methods 0.000 claims description 5
- 239000002808 molecular sieve Substances 0.000 claims description 5
- URGAHOPLAPQHLN-UHFFFAOYSA-N sodium aluminosilicate Chemical compound [Na+].[Al+3].[O-][Si]([O-])=O.[O-][Si]([O-])=O URGAHOPLAPQHLN-UHFFFAOYSA-N 0.000 claims description 5
- 239000013505 freshwater Substances 0.000 claims description 4
- 229910010272 inorganic material Inorganic materials 0.000 claims description 3
- 239000011147 inorganic material Substances 0.000 claims description 3
- 239000011368 organic material Substances 0.000 claims description 3
- 238000005086 pumping Methods 0.000 claims description 3
- 238000012163 sequencing technique Methods 0.000 claims description 3
- 230000000274 adsorptive effect Effects 0.000 claims description 2
- 238000012856 packing Methods 0.000 claims description 2
- 230000008016 vaporization Effects 0.000 claims description 2
- 150000001336 alkenes Chemical class 0.000 abstract description 12
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 abstract description 10
- 239000000047 product Substances 0.000 description 19
- 238000001914 filtration Methods 0.000 description 11
- 230000000694 effects Effects 0.000 description 10
- 238000000108 ultra-filtration Methods 0.000 description 8
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 7
- 150000001875 compounds Chemical class 0.000 description 7
- 239000001301 oxygen Substances 0.000 description 7
- 229910052760 oxygen Inorganic materials 0.000 description 7
- 238000011001 backwashing Methods 0.000 description 5
- 239000012528 membrane Substances 0.000 description 5
- 239000000498 cooling water Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 4
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- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- RHZUVFJBSILHOK-UHFFFAOYSA-N anthracen-1-ylmethanolate Chemical compound C1=CC=C2C=C3C(C[O-])=CC=CC3=CC2=C1 RHZUVFJBSILHOK-UHFFFAOYSA-N 0.000 description 2
- 239000007795 chemical reaction product Substances 0.000 description 2
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- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
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- -1 carbon olefins Chemical class 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
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- 230000001112 coagulating effect Effects 0.000 description 1
- 239000012141 concentrate Substances 0.000 description 1
- 238000006731 degradation reaction Methods 0.000 description 1
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- 238000001179 sorption measurement Methods 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C1/00—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon
- C07C1/20—Preparation of hydrocarbons from one or more compounds, none of them being a hydrocarbon starting from organic compounds containing only oxygen atoms as heteroatoms
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C7/00—Purification; Separation; Use of additives
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P30/00—Technologies relating to oil refining and petrochemical industry
- Y02P30/20—Technologies relating to oil refining and petrochemical industry using bio-feedstock
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P30/00—Technologies relating to oil refining and petrochemical industry
- Y02P30/40—Ethylene production
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
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- Oil, Petroleum & Natural Gas (AREA)
- Water Supply & Treatment (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention relates to a method and a device for purifying a boiling bed of methanol-to-olefin purified water, and provides a method for purifying a boiling bed of methanol-to-olefin purified water, which comprises the following steps: (i) sending the product gas to a quench tower for washing and cooling, and simultaneously washing most of catalyst fine powder carried in the product gas into quench water; (ii) sending the product gas obtained in the step (i) to a water washing tower for washing; (iii) recycling the quenching water obtained in the step (i) and the washing water obtained in the step (ii), discharging part of the quenching water to a stripping tower, and performing steam stripping to obtain purified water; (iv) (iv) further purifying the purified water obtained in step (iii) by means of a ebullated bed separator; (v) after the fluidized bed separator continuously operates for a period of time, the separation medium in the fluidized bed separator is regenerated through reverse feeding of purified water of a stripping tower; and (vi) further concentrating the catalyst slurry concentrated by the ebullated bed separator. Also provides a purification device of the boiling bed for preparing the olefin purified water from the methanol.
Description
Technical Field
The invention belongs to the technical field of high-concentration degradation-resistant sewage treatment, and relates to a method for treating purified water of methanol-to-olefin, which is suitable for removing and concentrating particulate matters in the purified water of methanol-to-olefin. Specifically, the disclosure provides a method and a device for purifying methanol-to-olefin purified water in a boiling bed.
Background
Methanol to olefins (mto) is a process for preparing low carbon olefins by catalytic reaction using methanol as a raw material. The reaction is generally realized by a fluidized bed reactor, and the catalyst used currently is SAPO-34 molecular sieve. Part of catalyst particles can be entrained in reaction product gas, and the catalyst is recovered by a three-stage or four-stage cyclone separator at present. And the product gas recovered by the catalyst is sent to a quench tower for cooling. The product gas after catalyst recovery also contains a small amount of catalyst fine powder with the particle size less than 2 mu m, part of the catalyst fine powder is left in the quenching water after being washed by the quenching tower, and the other part of the catalyst fine powder is sent to the water washing tower along with the gas phase, and the residual catalyst particles and oil wax substances are removed after being washed by the water washing tower and cooled. Because 54% of reaction products in the MTO process are water, in order to keep the balance of water amount in a quenching and washing system, a part of quenching water and washing water are discharged from a quenching tower and a washing tower to a stripping tower, oxygen-containing compounds in stripping water are returned to a reactor for recycling, and purified water at the bottom of the stripping tower is subjected to heat exchange and cooling and then is sent to a sewage treatment plant for treatment and utilization. Because the quenching water and the washing water contain catalyst fine powder, especially the content of the catalyst fine powder in the quenching water is as high as 300-500mg/L, the purified water contains a large amount of fine catalyst fine powder which is difficult to biodegrade and settle, and because the processing capacity of the stripping tower is limited, heavy hydrocarbon substances are difficult to strip out, so that the purified water still contains the heavy hydrocarbon substances. The presence of fine catalysts and heavy hydrocarbons greatly increases the treatment burden of the purified water in sewage treatment plants. In order to reduce the treatment load of purified water, it is necessary to effectively remove particulate matter and heavy hydrocarbons from purified water.
Chinese invention patent application CN101352621A discloses a cyclone separation and solidification method and device for MTO quench water and washing water, Chinese invention patent application CN 101352620A discloses a micro cyclone concentration method and device for fine catalyst in MTO quench water and washing water, Chinese invention patent CN 102093153B discloses a method and device for optimized combination and purification and separation of MTO reaction gas containing catalyst micro powder, and the methods remove catalyst carried in quench water and washing water through a micro cyclone separator. However, due to the limitation of the separation precision of the cyclone separator, when the method is actually applied, the separation effect on particles with the particle size of below 2.5 μm is poor, so that fine particles cannot be effectively removed, solid content is continuously increased due to accumulation in a quenching water system, a quenching water heat exchanger and an air cooler are seriously blocked, and the heat exchange efficiency is influenced.
Chinese utility model patent CN205031975U discloses a MTO rapid cooling water and washing water purification processing apparatus, chinese invention patent application CN 104649446a discloses an MTO rapid cooling water and washing water liquid-solid separation method and apparatus, above method all adopts microfiltration to separate and concentrate the catalyst in rapid cooling water, washing water, but because the catalyst particle diameter that sharp cooling water, washing water smuggleing secretly is little, and the aquatic contains a small amount of oil wax class material, lead to the filter to block up easily in the actual operation process, and online recoil regeneration is difficult, cause equipment operation pressure differential too big, unable normal use.
Chinese patent application CN102050548A discloses a MTO wastewater treatment method, and Chinese patent application CN105330086A discloses a methanol-to-olefin wastewater treatment method, and the methods remove colloids and suspended matters in water by homogeneous regulation and coagulating sedimentation. However, in the practical application of these methods, the area occupied by the homogenizing tank and the sedimentation tank is large, the treatment period is long, and coagulant and flocculant need to be continuously added, so that the running cost is high. The solid content of the purified water treated by the methods is still about 100mg/L, the removal efficiency of suspended solids is low, and fine particles which are not easy to settle cannot be effectively removed.
The Chinese patent application CN10192246A discloses a method for treating and recycling MTO process wastewater, which removes colloids and suspended matters in water by flocculation precipitation and ultrafiltration membrane filtration. In practical application, the method has the advantages that the occupied area of the sedimentation tank is large, the filtering operation period of the ultrafiltration membrane is as short as 45-90 minutes, and the treatment capacity is only 50-1000L/m3h, acid-base agents are required to be added in the back washing regeneration process, so that the investment and operation cost of the method are high.
The methods of the above patents have various industrial application obstacles, namely, the micro-cyclone liquid-solid separation precision is limited, the efficiency is not high, the precise filtration and ultrafiltration membrane filtration equipment is easy to block, the cleaning and regeneration are difficult, the operation cost is high, and the purification treatment device is not arranged behind the stripping tower, so the treatment burden of the sewage treatment plant is increased.
In view of the above drawbacks of the prior art, there is a need in the art to develop a method for purifying water from methanol to olefin, which can overcome the above drawbacks of the prior art.
Disclosure of Invention
The utility model provides a novel boiling bed purification method and device for methanol to olefin purified water, which adds a set of boiling bed separation device for purified water behind a stripping tower to remove fine catalyst and heavy hydrocarbon substances in the purified water, thereby reducing the burden of sewage treatment, realizing the purposes of concentrating the waste catalyst in the purified water of the methanol to olefin device and purifying the purified water, and solving the problems of incomplete separation, short equipment operation period and high operation cost of the prior method.
In one aspect, the present disclosure provides a method for purifying Methanol To Olefin (MTO) purified water in a fluidized bed, comprising the steps of:
(i) removing catalyst particles from a product gas obtained by the reaction of the methanol raw material, then sending the product gas to a quench tower for washing and cooling, and simultaneously washing most of catalyst fine powder carried in the product gas into quench water;
(ii) the product gas which is washed and cooled by the quench tower and carries a small part of catalyst fine powder is sent to a water washing tower for washing, and the product gas is washed and cooled again to wash away the catalyst fine powder and the oil wax substances which are condensed;
(iii) recycling the quenching water obtained in the step (i) and the washing water obtained in the step (ii), discharging part of the quenching water to a stripping tower, and feeding organic matters in the stripping water to a recycling device for stripping to obtain purified water;
(iv) (iv) the purified water obtained in step (iii) is further purified by an ebullated bed separator to remove a small amount of catalyst particles and heavy hydrocarbons entrained therein;
(v) after the boiling bed separator continuously operates for a period of time, the separation medium in the boiling bed separator is regenerated through reverse feeding of purified water of a stripping tower, and heavy hydrocarbon substances adsorbed by the separation medium and catalyst particles adsorbed by the separation medium and accumulated among the separation media are released; and
(vi) the catalyst slurry concentrated by the boiling bed separator is further concentrated.
In a preferred embodiment, the purified water obtained in step (iii) has a solid particle content of 20 to 110mg/L and an average particle diameter of the solid particles of 0.5 to 5 μm; after separation by the ebullated bed separator in step (iv), the solid particle content is reduced to below 5mg/L, and the average particle size of the solid particles is reduced to below 0.5 μm.
In another preferred embodiment, the purified water obtained in step (iii) has a heavy hydrocarbons content of 150-250 mg/L; and (3) after separation by the ebullated bed separator in the step (iv), the content of heavy hydrocarbon substances is reduced to below 20 mg/L.
In another preferred embodiment, in step (iii), part of the quench water obtained in step (i) and part of the water-washing water obtained in step (ii) are returned to the top of the quench tower and the top of the water-washing tower for recycling after heat exchange and temperature reduction through an air cooler and a heat exchanger, part of the water-washing water is discharged to a settling tank for sedimentation and then pumped into a stripping tower, and organic matters in the stripping water are partially refluxed through a reflux tank and partially sent to a back-smelting device.
In another preferred embodiment, in step (iv), part of the purified water obtained from the bottom of the stripping tower is vaporized by a kettle reboiler and used as stripping steam, and part of the purified water is sent to a sewage treatment plant after a boiling bed separator removes a small amount of catalyst particles and heavy hydrocarbons entrained therein.
In another aspect, the present disclosure provides a methanol to olefins purification water boiling bed purification device, including:
a quenching tower, which is used for removing catalyst particles from a product gas obtained by the reaction of the methanol raw material in the step (i), sending the product gas to the quenching tower for washing and cooling, and washing most of catalyst fine powder carried in the product gas to quenching water;
the water washing tower is connected with the quenching tower and is used for carrying out the step (ii), the product gas which is washed by the quenching tower and cooled and carries a small part of catalyst fine powder is sent to the water washing tower again for washing, and the catalyst fine powder and the oil wax substances which are condensed and carried in the product gas are washed and cooled again;
a stripping tower connected with the water washing tower and used for recycling part of the quenching water obtained in the step (iii) and the water washing water obtained in the step (ii), discharging part of the quenching water out of the stripping tower, and sending organic matters in the stripping water to a recycling device for stripping to obtain purified water; and
(iv) an ebullated bed separator connected to the stripping column for performing step (iv) and further purifying the purified water obtained in step (iii) by the ebullated bed separator to remove entrained small amounts of catalyst particles and heavy hydrocarbons.
In another preferred embodiment, the ebullated-bed separator is operated intermittently, and after a certain period of continuous operation or after a certain pressure loss, the separation medium is fluidized to boiling by the reverse introduction of purified or fresh water and nitrogen or steam, and is regenerated; the pressure loss of the boiling bed separator is 0.01-0.30 MPa.
In another preferred embodiment, the ebullated bed separator employs one or more particulate separation media having a particle size of 0.1 to 2mm, being an organic or inorganic material having adsorptive properties for molecular sieve catalyst particles and heavy hydrocarbon species, the separation media having a stack height of 500-5000 mm.
In another preferred embodiment, the ebullated-bed separator enhances separation medium regeneration by creating a cyclonic field in its top cyclonic separation apparatus, while achieving recovery and sequencing of the separated medium particles during ebullated regeneration.
In another preferred embodiment, the apparatus further comprises:
a settling tank arranged between the water washing tower and the stripping tower and used for discharging the quenching water obtained in the step (i) and the water washing water obtained in the step (ii) to the settling tank for settling and then pumping into the stripping tower;
the reflux tank is connected with the stripping tower and is used for partially refluxing the organic matters in the stripping water through the reflux tank; and
and the kettle-type reboiler is connected with the stripping tower and is used for vaporizing part of the purified water obtained at the bottom of the stripping tower through the kettle-type reboiler to serve as stripping steam.
Has the advantages that:
1) the method of the invention adopts the particle bed in the boiling bed separator to carry out deep filtration on the purified water, and makes up the problem that the separation efficiency of the original micro cyclone separator group on particles smaller than 2 mu m is insufficient.
2) The method of the invention utilizes the particle bed in the boiling bed separator to purify the purified water, and gradually reduces the content of the particulate matters in the water along with the depth of the filter layer through the functions of sieving, intercepting, adsorbing and the like of the separation medium on the particles in the water.
3) The method of the invention utilizes the particle bed in the boiling bed separator to carry out deep filtration on the purified water, and the granular packing has strong adsorption effect on heavy hydrocarbon substances while adsorbing and intercepting catalyst particles.
4) The method of the invention utilizes a boiling method to regenerate the separation medium, enhances the regeneration effect of the separation medium through the rotational flow field formed in the rotational flow separation device at the top of the equipment, and simultaneously realizes the recovery of medium particles during boiling regeneration.
Drawings
The accompanying drawings are included to provide a further understanding of the disclosure, and are incorporated in and constitute a part of this specification to further illustrate the disclosure and not limit the disclosure.
FIG. 1 is a schematic diagram of the overall process flow of a methanol to olefin purification water purification process according to a preferred embodiment of the present disclosure.
FIG. 2 is a schematic process flow diagram of an ebullated bed separation system according to a preferred embodiment of the present disclosure.
Detailed Description
After extensive and intensive research, the inventor of the application finds that the most effective and lowest-cost method for a liquid-solid system, namely the purified water of a methanol-to-olefin device, which has the advantages of large operation flow, low solid content, small particle size and heavy hydrocarbon substances is to separate by adopting a micro cyclone separator group; however, in practical application, the method has a poor effect of separating particles smaller than 2 μm in purified water, and a primary ultrafiltration membrane filtering device is usually connected in series behind a micro cyclone separator group; but the ultrafiltration membrane filtering device has limited treatment capacity, short continuous operation time and large difficulty in cleaning the filtration membrane, and a medicament needs to be added, so that the operation cost is increased; in order to solve the problems, namely higher filtration efficiency and larger treatment capacity are achieved, a boiling bed separator is adopted to separate catalyst particles in the water by using a methanol-to-olefin device, the method not only solves the problem that the separation efficiency of particles smaller than 2 microns is not enough by using the original micro cyclone separator group, but also avoids the defects of small treatment capacity and frequent back washing of an ultrafiltration membrane filtration method, and compared with the ultrafiltration membrane filtration method, the method has the advantages of lower equipment cost, lower energy consumption and more reliable operation, realizes the deep removal of nano-micron particles and heavy hydrocarbons in the purified water, and reduces the concentration of suspended matters and the content of heavy hydrocarbons in the purified water. Based on the above findings, the present invention has been completed.
In a first aspect of the present disclosure, there is provided a method for purifying a methanol to olefin purified water boiling bed, the method comprising the steps of:
the methanol raw material reacts in a fluidized bed reactor, the product gas is sent to a quench tower for washing and cooling after catalyst particles are recovered by a multi-stage cyclone separator, and meanwhile, part of catalyst fine powder carried in the product gas is washed into quench water;
sending the product gas which is washed and cooled by the quenching tower and carries part of catalyst fine powder to a washing tower for washing, cooling again and washing away oil wax substances condensed in the product gas and residual catalyst fine powder;
the quenching water and the washing water are recycled after heat recovery and cooling through a heat exchanger and an air cooler and are respectively circulated in a quenching system and a washing system;
discharging a part of the quenching water and the washing water to a stripping tower, and discharging organic matters in the stripping water to a recycling device;
carrying out liquid-solid separation on the purified water through a fluidized bed separator, removing catalyst fine powder and heavy hydrocarbon substances carried in the water, and then sending the water to a sewage treatment plant;
after the boiling bed separator continuously operates for a period of time, the separation medium is regenerated by purifying water or fresh water and reversely feeding water vapor or nitrogen through a stripping tower, and the adsorbed catalyst particles and heavy hydrocarbon substances are released; and
the slurry concentrated by the ebullated bed separator is sent to a settling tank for further treatment.
In the disclosure, the working temperature of the purified water is 120-150 ℃, the solid particles are methanol-to-olefin catalyst fine powder, and are usually crushed SAPO-34 molecular sieve with the content of 20-110mg/L, the average particle size of 0.5-5 μm, and the content of heavy hydrocarbon substances is 150-250 mg/L.
In the present disclosure, after the purified water is separated by the boiling bed, the catalyst content in the water is reduced to be below 5mg/L, the average particle size is reduced to be below 0.5 μm, and the heavy hydrocarbon content is reduced to be below 20 mg/L.
In the present disclosure, the ebullated-bed separator pressure loss is 0.01 to 0.30 MPa.
In the disclosure, the ebullated bed separator is operated intermittently, the particle bed filtration is performed during the separation operation, the operation is switched to the regeneration operation after a certain time of continuous operation, the separation medium is fluidized to be ebullated by reversely introducing the stripper purified water or fresh water, the separation medium is cleaned and regenerated, and a certain amount of nitrogen or steam can be introduced to enhance the ebullated regeneration effect.
In a second aspect of the present disclosure, there is provided a methanol to olefin purified water ebullated-bed purification apparatus, comprising: the system comprises a quenching tower, a water washing tower connected with the quenching tower, a stripping tower connected with the water washing tower, and a boiling bed separator connected with the stripping tower.
In the present disclosure, the apparatus further comprises: a settling tank arranged between the water washing tower and the stripping tower, a reflux tank connected with the stripping tower, and a kettle-type reboiler connected with the stripping tower.
In the disclosure, the fluidized bed separator adopts one or more granular separation media, the material is organic or inorganic material having adsorbability to molecular sieve catalyst particles and heavy hydrocarbon substances, the separation media can be quartz sand, anthracite, nut shells, activated carbon, carbon balls, ceramic balls or other granular separation media, and can also be a combination of multiple separation media, the particle size of the separation media is 0.1-2mm, and the stacking height of the separation media is 500-5000 mm; through the sieving, intercepting and adsorbing effects of the separation medium on the particles and heavy hydrocarbon substances in the water, the content of the particles and the oil in the water is gradually reduced along with the depth of the filter layer, and the purification of the purified water is realized.
In the present disclosure, the ebullated-bed separator enhances the regeneration effect of the separation medium by the cyclone field formed in the top cyclone separation device, and simultaneously realizes the recovery and sequencing of medium particles during ebullated regeneration.
The methanol-to-olefin purification water boiling bed purification device can be popularized to heterogeneous separation occasions where various liquids carry fine particles or various organic matters.
Reference is made to the accompanying drawings.
FIG. 1 is a schematic diagram of the overall process flow of a methanol to olefin purification water purification process according to a preferred embodiment of the present disclosure. As shown in fig. 1, the product gas containing catalyst particles and various byproducts is sent to a quenching tower 1-2 for washing and cooling, after washing off part of the entrained catalyst, the product gas is sent to a water washing tower 1-1 for cooling again, the entrained catalyst particles and oil wax substances are washed off, and the product gas is sent to a subsequent treatment system; after heat exchange and temperature reduction of the quenching water and the washing water through an air cooler and a heat exchanger, returning to the tower top to circulate in a quenching and washing system; discharging a part of quenching water and a part of washing water out respectively to a settling tank 1-3, pumping into a stripping tower 1-4 to strip oxygen-containing compounds in water, refluxing the part of the oxygen-containing compounds in the stripping water through a reflux tank 1-6, dividing the part of the oxygen-containing compounds into two parts, sending one part of the oxygen-containing compounds to a reactor for recycling, and discharging the other part of the oxygen-containing compounds to a concentration water tank after pressurizing the other part of the oxygen-containing compounds; the part of the purified water at the bottom of the stripping tower is vaporized by a kettle-type reboiler 1-5, and then a part of the purified water is used as stripping steam, the other part of the condensed water is discharged, and the other part of the purified water is sent to a decontamination water treatment plant after catalyst particles and heavy hydrocarbon substances in the water are removed by a boiling bed separator 1-7; the fluidized bed separation system mainly comprises a plurality of fluidized bed separators; after the boiling bed separator continuously operates for a period of time, the separation medium is regenerated by reverse feeding of purified water of the stripping tower, the adsorbed catalyst particles and heavy hydrocarbon substances are released, and the regenerated concentrated solution is sent to a concentration system.
FIG. 2 is a schematic process flow diagram of an ebullated bed separation system according to a preferred embodiment of the present disclosure. As shown in fig. 2, the ebullated bed separation system can be operated by connecting a plurality of ebullated bed separators in parallel, purified water is fed from an inlet at the top of the equipment and discharged from an outlet at the bottom of the equipment during normal operation, and the treated purified water is sent to a decontamination water treatment plant; when the equipment continuously operates for a certain time or the pressure difference rises to a certain value, the equipment is switched to back washing operation in turn; during back flushing, closing an inlet valve 2-1 and an outlet valve 2-2 of the device, opening a blowdown valve 2-3 and an exhaust valve 2-4, simultaneously opening a nitrogen inlet valve 2-5 and a back flushing valve 2-6, changing a particle bed in the separator into a boiling state by purifying water and nitrogen, releasing pollutants intercepted and adsorbed in the particle bed, and realizing the regeneration of a separation medium; the regenerated pollutant slurry is discharged from a sewage outlet and sent to a settling tank for further treatment, and mixed waste gas formed after the nitrogen entering through a bottom nitrogen inlet valve is subjected to a regeneration process is also discharged from the sewage outlet.
Examples
The invention is further illustrated below with reference to specific examples. It is to be understood, however, that these examples are illustrative only and are not to be construed as limiting the scope of the present invention. Test methods in which specific conditions are not specified in the following examples are generally carried out under conventional conditions or under conditions recommended by the manufacturer. All percentages and parts are by weight unless otherwise indicated.
Example 1:
in a process of preparing olefin by methanol at 60 ten thousand tons/year, according to the method of the invention, a small experimental facility of ebullated bed separation is adopted for carrying out a side line test on purified water containing a solid catalyst, and the specific operation process and effect are described as follows:
1. material Properties and associated parameters
The methanol-to-olefin purified water is a liquid-solid two-phase mixture, and the water contains solid catalyst fine powder, wherein the water is a continuous phase, and the solid catalyst is a disperse phase medium. The treatment capacity of the experimental device is 50L/h, and the density of the experimental device is 915.4kg/m under the liquid phase operation state3Viscosity of 0.255cP, operation temperature of 139 ℃, content of the waste catalyst of 60mg/L, average particle size of 2.0 μm and oil content of 150 mg/L.
2. Purifying water purifying device
The device is a single boiling bed separator with the diameter of 72mm, the separation medium is modified anthracite with the particle size of 1-2mm, the height of a particle bed layer is 1000mm, and the treatment capacity of a single filter is 50L/h.
3. Carrying out the process
Sending the methanol-to-olefin purified water containing the catalyst fine powder to a fluidized bed separation experimental device, removing particulate matters in the water after passing through a particle bed layer, and discharging the particulate matters; continuously operating until the pressure difference is increased to 0.3MPa, and switching back washing operation.
4. Analysis of results
Through the purification effect of the boiling bed separator, the solid content of the purified water is reduced to be below 5mg/L from 60mg/L, the removal rate exceeds 80 percent, the oil content of the purified water is reduced to be below 20mg/L from 150mg/L, the removal rate exceeds 85 percent, and the operation average pressure drop of the boiling bed separator is 0.03 MPa; during the test period, the initial separation effect can be continuously maintained after 300 hours of continuous operation and 20 times of backwashing regeneration operation, and the separation efficiency exceeds 80 percent.
In addition, the particle bed filtering method is used for purifying the purified water of the methanol-to-olefin stripping tower, so that the separation precision is improved, and the defects of short operation period and incomplete regeneration of the original ultrafiltration membrane filtering method are overcome.
The above-listed embodiments are merely preferred embodiments of the present disclosure, and are not intended to limit the scope of the present disclosure. That is, all equivalent changes and modifications made according to the contents of the claims of the present application should be considered to be within the technical scope of the present disclosure.
All documents referred to in this disclosure are incorporated by reference into this application as if each were individually incorporated by reference. Furthermore, it should be understood that various changes or modifications to the disclosure may be made by those skilled in the art after reading the above teachings of the disclosure, and such equivalents may fall within the scope of the disclosure as defined by the appended claims.
Claims (10)
1. A method for purifying methanol-to-olefin purified water by a boiling bed comprises the following steps:
(i) removing catalyst particles from a product gas obtained by the reaction of the methanol raw material, then sending the product gas to a quench tower for washing and cooling, and simultaneously washing most of catalyst fine powder carried in the product gas into quench water;
(ii) the product gas which is washed and cooled by the quench tower and carries a small part of catalyst fine powder is sent to a water washing tower for washing, and the product gas is washed and cooled again to wash away the catalyst fine powder and the oil wax substances which are condensed;
(iii) recycling the quenching water obtained in the step (i) and the washing water obtained in the step (ii), discharging part of the quenching water to a stripping tower, and feeding organic matters in the stripping water to a recycling device for stripping to obtain purified water;
(iv) (iv) the purified water obtained in step (iii) is further purified by an ebullated bed separator to remove a small amount of catalyst particles and heavy hydrocarbons entrained therein;
(v) after the boiling bed separator continuously operates for a period of time, the separation medium in the boiling bed separator is regenerated through reverse feeding of purified water of a stripping tower, and heavy hydrocarbon substances adsorbed by the separation medium and catalyst particles adsorbed by the separation medium and accumulated among the separation media are released; and
(vi) the catalyst slurry concentrated by the boiling bed separator is further concentrated.
2. The method according to claim 1, wherein the purified water obtained in step (iii) has a solid particle content of 20 to 110mg/L and an average particle size of 0.5 to 5 μm; after separation by the ebullated bed separator in step (iv), the solid particle content is reduced to below 5mg/L, and the average particle size of the solid particles is reduced to below 0.5 μm.
3. The process as claimed in claim 1, wherein the purified water obtained in step (iii) has a heavy hydrocarbon content of 150-250 mg/L; and (3) after separation by the ebullated bed separator in the step (iv), the content of heavy hydrocarbon substances is reduced to below 20 mg/L.
4. The method of claim 1, wherein in step (iii), part of the quench water obtained in step (i) and part of the water washing water obtained in step (ii) are cooled by heat exchange of an air cooler and a heat exchanger and then returned to the top of the quench tower and the top of the water washing tower for recycling, part of the quench water and the water washing water is discharged to a settling tank for settling and then pumped into a stripping tower, and organic matters in the stripping water are partially refluxed through a reflux tank and partially sent to a remilling device.
5. The process of claim 1, wherein in step (iv), part of the purified water obtained from the bottom of the stripping tower is vaporized by the kettle reboiler and used as stripping steam, and part of the purified water is removed with a small amount of catalyst particles and heavy hydrocarbons entrained in the purified water by the ebullated bed separator and sent to a sewage treatment plant.
6. A methanol-to-olefin (MTO) purified water boiling bed purification device comprises:
a quenching tower (1-2) used for removing catalyst particles from a product gas obtained by the reaction of the methanol raw material in the step (i), then sending the product gas to the quenching tower for washing and cooling, and simultaneously washing most of catalyst fine powder carried in the product gas to quenching water;
the water washing tower (1-1) is connected with the quenching tower (1-2) and is used for carrying out the step (ii), washing and cooling the product gas which is carried with a small part of catalyst fine powder by the quenching tower and then sending the product gas to the water washing tower for washing, washing and cooling again and washing the catalyst fine powder carried with the product gas and oil wax substances condensed;
the stripping tower (1-4) is connected with the water washing tower (1-1) and is used for recycling the quenching water obtained in the step (iii) and the washing water obtained in the step (ii), discharging part of the quenching water to the stripping tower, recycling organic matters in the stripping water to a recycling device, and stripping to obtain purified water; and
and (iv) an ebullated bed separator (1-7) connected to the stripping column (1-4) for further purifying the purified water obtained in step (iv) by the ebullated bed separator to remove entrained small amounts of catalyst particles and heavy hydrocarbons.
7. The apparatus according to claim 6, wherein the ebullated bed separator is operated intermittently, and is regenerated by fluidizing the separation medium in the ebullated state by reverse feeding of purified or fresh water and nitrogen or steam after a certain period of continuous operation or after a certain pressure loss; the pressure loss of the boiling bed separator is 0.01-0.30 MPa.
8. The apparatus as claimed in claim 7, wherein the ebullated bed separator employs one or more particulate separation media having a particle size of 0.1-2mm, being an organic or inorganic material having adsorptive properties for molecular sieve catalyst particles and heavy hydrocarbon species, and having a packing height of 500-5000 mm.
9. The apparatus of claim 7 wherein the ebullated-bed separator enhances separation medium regeneration by creating a cyclonic field in the top cyclonic separation device while achieving recovery and sequencing of the particles of separation medium during ebullated regeneration.
10. The apparatus of claim 6, further comprising:
a settling tank (1-3) arranged between the water washing tower (1-1) and the stripping tower (1-4) and used for discharging the quenching water obtained in the step (i) and the water washing water obtained in the step (ii) to the settling tank for settling and then pumping into the stripping tower;
the reflux tank (1-6) is connected with the stripping tower (1-4) and is used for partially refluxing the organic matters in the stripping water through the reflux tank; and
and the kettle type reboiler (1-5) is connected with the stripping tower (1-4) and is used for vaporizing part of the purified water obtained at the bottom of the stripping tower by the kettle type reboiler to serve as stripping steam.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115215460A (en) * | 2022-08-11 | 2022-10-21 | 华东理工大学 | Water-saving method and device for hydrocracking device |
| CN116282633A (en) * | 2023-01-04 | 2023-06-23 | 中国神华煤制油化工有限公司 | Water treatment method and water treatment system in purifying methanol-to-olefin product gas |
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2021
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Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN115215460A (en) * | 2022-08-11 | 2022-10-21 | 华东理工大学 | Water-saving method and device for hydrocracking device |
| CN115215460B (en) * | 2022-08-11 | 2023-08-01 | 华东理工大学 | Water saving method and device for hydrocracking device |
| CN116282633A (en) * | 2023-01-04 | 2023-06-23 | 中国神华煤制油化工有限公司 | Water treatment method and water treatment system in purifying methanol-to-olefin product gas |
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