CN116410058A - Process method for separating coal-based ethanol - Google Patents
Process method for separating coal-based ethanol Download PDFInfo
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- CN116410058A CN116410058A CN202111643580.2A CN202111643580A CN116410058A CN 116410058 A CN116410058 A CN 116410058A CN 202111643580 A CN202111643580 A CN 202111643580A CN 116410058 A CN116410058 A CN 116410058A
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- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 title claims abstract description 473
- 238000000034 method Methods 0.000 title claims abstract description 53
- 230000008569 process Effects 0.000 title claims abstract description 37
- 239000003245 coal Substances 0.000 title claims abstract description 16
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims abstract description 252
- 235000019441 ethanol Nutrition 0.000 claims abstract description 167
- XEKOWRVHYACXOJ-UHFFFAOYSA-N Ethyl acetate Chemical compound CCOC(C)=O XEKOWRVHYACXOJ-UHFFFAOYSA-N 0.000 claims abstract description 90
- XBDQKXXYIPTUBI-UHFFFAOYSA-M Propionate Chemical compound CCC([O-])=O XBDQKXXYIPTUBI-UHFFFAOYSA-M 0.000 claims abstract description 38
- KXKVLQRXCPHEJC-UHFFFAOYSA-N acetic acid trimethyl ester Natural products COC(C)=O KXKVLQRXCPHEJC-UHFFFAOYSA-N 0.000 claims abstract description 38
- 238000006297 dehydration reaction Methods 0.000 claims abstract description 31
- 230000018044 dehydration Effects 0.000 claims abstract description 30
- 238000000926 separation method Methods 0.000 claims abstract description 30
- 239000000203 mixture Substances 0.000 claims abstract description 21
- 239000002994 raw material Substances 0.000 claims abstract description 20
- 238000004519 manufacturing process Methods 0.000 claims abstract description 9
- LCGLNKUTAGEVQW-UHFFFAOYSA-N Dimethyl ether Chemical compound COC LCGLNKUTAGEVQW-UHFFFAOYSA-N 0.000 claims description 48
- 239000007789 gas Substances 0.000 claims description 43
- 239000000463 material Substances 0.000 claims description 30
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims description 24
- 238000010992 reflux Methods 0.000 claims description 17
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 11
- 101000623895 Bos taurus Mucin-15 Proteins 0.000 claims description 6
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 claims description 5
- VXNZUUAINFGPBY-UHFFFAOYSA-N 1-Butene Chemical compound CCC=C VXNZUUAINFGPBY-UHFFFAOYSA-N 0.000 claims description 4
- XKRFYHLGVUSROY-UHFFFAOYSA-N Argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 4
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 4
- IAQRGUVFOMOMEM-UHFFFAOYSA-N butene Natural products CC=CC IAQRGUVFOMOMEM-UHFFFAOYSA-N 0.000 claims description 4
- 239000002808 molecular sieve Substances 0.000 claims description 3
- 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 3
- 229910052786 argon Inorganic materials 0.000 claims description 2
- 239000012528 membrane Substances 0.000 claims description 2
- 229910052757 nitrogen Inorganic materials 0.000 claims description 2
- 238000012856 packing Methods 0.000 claims description 2
- 238000001179 sorption measurement Methods 0.000 claims description 2
- 238000004457 water analysis Methods 0.000 claims description 2
- 238000005516 engineering process Methods 0.000 abstract description 8
- 238000005984 hydrogenation reaction Methods 0.000 abstract description 7
- 238000011144 upstream manufacturing Methods 0.000 abstract description 7
- 238000005265 energy consumption Methods 0.000 abstract description 6
- 230000008901 benefit Effects 0.000 abstract description 3
- 238000010168 coupling process Methods 0.000 abstract description 3
- 230000008878 coupling Effects 0.000 abstract description 2
- 238000005859 coupling reaction Methods 0.000 abstract description 2
- 239000002351 wastewater Substances 0.000 abstract description 2
- 239000000047 product Substances 0.000 description 32
- 150000002148 esters Chemical class 0.000 description 8
- 238000006243 chemical reaction Methods 0.000 description 7
- 238000005810 carbonylation reaction Methods 0.000 description 6
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- 239000003054 catalyst Substances 0.000 description 4
- 238000011084 recovery Methods 0.000 description 4
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 3
- 238000001816 cooling Methods 0.000 description 3
- 238000013461 design Methods 0.000 description 3
- QUSNBJAOOMFDIB-UHFFFAOYSA-N Ethylamine Chemical compound CCN QUSNBJAOOMFDIB-UHFFFAOYSA-N 0.000 description 2
- 150000001298 alcohols Chemical class 0.000 description 2
- 239000007795 chemical reaction product Substances 0.000 description 2
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- 229910000510 noble metal Inorganic materials 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- IKHGUXGNUITLKF-XPULMUKRSA-N acetaldehyde Chemical compound [14CH]([14CH3])=O IKHGUXGNUITLKF-XPULMUKRSA-N 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 230000004075 alteration Effects 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 239000010949 copper Substances 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
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- 239000000975 dye Substances 0.000 description 1
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- IDGUHHHQCWSQLU-UHFFFAOYSA-N ethanol;hydrate Chemical compound O.CCO IDGUHHHQCWSQLU-UHFFFAOYSA-N 0.000 description 1
- 238000000605 extraction Methods 0.000 description 1
- 238000000855 fermentation Methods 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
- C07C29/76—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment
- C07C29/80—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment by distillation
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
- C07C29/76—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
- C07C29/76—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment
- C07C29/80—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment by distillation
- C07C29/82—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment by distillation by azeotropic distillation
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The application discloses a process method for separating coal-based ethanol, which comprises the steps of sequentially rectifying and separating raw materials through a first rectifying tower, a second rectifying tower, a third rectifying tower and a fourth rectifying tower to obtain aqueous ethanol, recovering methanol, a mixture of ethyl acetate and methyl acetate, noncondensable gas, heavy alcohol and the like. The methanol, ethyl acetate and methyl acetate mixture is recovered and returned to the upstream system. The absolute ethanol product and the alcohol-containing wastewater are obtained by the ethanol dehydration unit of the absolute ethanol. The process can separate hydrogenation product fully to obtain high purity absolute ethyl alcohol product, and other separated matters meet the requirement of circulation or discharge standard. By adopting the double-effect rectification thermal coupling technology, the separation energy consumption is reduced to the greatest extent, the problems are better solved, and the method has good economic and social benefits and can be used in actual production.
Description
Technical Field
The application relates to a process method for separating coal-based ethanol, which belongs to the field of anhydrous ethanol product separation in coal chemical industry coal-based ethanol (dimethyl ether route) process.
Background
Ethanol is an important bulk chemical, has very wide application, and is mainly used in the industries of medicine, energy chemical industry, food, national defense construction and the like. As industrial raw materials, ethanol can be used for preparing chemical products such as acetaldehyde, diethyl ether, ethylamine, ethyl acetate and the like, and plays a vital role in the production process of paint, dye and detergent. In the field of fuel energy, ethanol is a relatively promising oxygen-enriched renewable energy source, an internationally recognized clean fuel and an excellent oil quality improver. Worldwide, the production process of ethanol comprises a biological fermentation method, a petrochemical method and a coal chemical method.
The process of preparing alcohol by coal chemical route is to prepare synthetic gas and methanol first and then to prepare alcohol by dimethyl ether or acetic acid. The industrial production of ethanol by acetic acid hydrogenation mainly has the problems of high price of noble metals such as Rh, pt and the like, high cost and low conversion rate of acetic acid, and besides, the separation of ethanol which is a target product is difficult due to more side reactions in the reaction process of preparing ethanol by acetic acid hydrogenation and the like, which is not suitable for large-scale production. However, the production link of acetic acid does not exist in the process of preparing ethanol by carbonylation of dimethyl ether, the dimethyl ether is synthesized by the methanol through dehydration reaction, and the synthesis gas is separated into two steps to prepare the ethanol by the dimethyl ether. Firstly, dimethyl ether is subjected to carbonylation reaction under the action of a catalyst to synthesize methyl acetate, the methyl acetate and hydrogen are subjected to hydrogenation reaction to generate crude ethanol, and the crude ethanol is separated and refined to obtain target product ethanol. The process route mainly adopts a molecular sieve catalyst or a copper-based catalyst, does not need a noble metal catalyst, has relatively low production cost, and has better atomic utilization rate and higher selectivity of the product ethanol compared with other methods for synthesizing ethanol by using coal; only a trace amount of acetic acid is generated in the whole reaction process, and the corrosion degree of equipment is very low, so that no special requirement is made on the material of the equipment.
In recent years, coal-based ethanol technology is continuously developed and industrially developed in China, and the industrial demonstration project of preparing ethanol by carbonylation of dimethyl ether with the annual yield of 10 ten thousand tons, which is researched and developed by a large-scale company and an extended petroleum group, falls to the ground, and the whole process is conducted in 2017, so that qualified absolute ethanol is produced, and long-time stable operation is realized.
However, the process involves more azeotrope which is difficult to separate, the section for separating the crude ethanol occupies larger energy consumption, and the research on a separation process scheme with high efficiency, energy conservation and high recovery rate has great significance for optimizing the process for preparing the ethanol by carbonylation of dimethyl ether.
Disclosure of Invention
The invention provides a thermal coupling method for a coal-based ethanol separation process, which aims to solve the separation energy consumption problem in the coal-based ethanol (dimethyl ether route) process, and effectively reduces the whole energy consumption of the process. The process method adopts a double-effect energy-saving rectification thermal coupling technology, the new technology has the advantages of reasonable flow, lower energy consumption, high recovery rate and purity of ethanol products and the like, achieves the purpose of energy conservation and has good economic benefit, the double-effect rectification technology belongs to a high-efficiency rectification energy-saving technology, the reboiler of a low-temperature tower is heated by using secondary energy of a material with the height of Wen Dading in the device, and the energy-saving effect is obvious by adopting the process scheme of the double-effect tower.
In one aspect of the present application, a process for coal-based ethanol separation is provided, the process comprising the steps of:
(1) The raw materials are subjected to rectification separation in a first rectifying tower to obtain a gas phase containing a light component A and a heavy component material I;
(2) The heavy component material I enters a second rectifying tower, and an azeotrope I containing methanol, methyl acetate and ethyl acetate, an aqueous ethanol I and a heavy component material II are obtained after rectification and separation;
(3) The heavy component material II enters a third rectifying tower and is subjected to rectification separation to obtain hydrous ethanol II and heavy component B;
the azeotrope I containing methanol, methyl acetate and ethyl acetate enters a fourth rectifying tower, and is subjected to rectification separation to obtain a mixture containing methanol and ethanol and an azeotrope II containing methanol, methyl acetate and ethyl acetate;
the aqueous ethanol I enters an ethanol dehydration unit and is dehydrated to obtain absolute ethanol;
(4) The hydrous ethanol II enters an ethanol dehydration unit and is dehydrated to obtain absolute ethanol;
the mixture containing the ethanol enters a second rectifying tower and is mixed with a heavy component material I, and the step (2) is repeated;
wherein the raw materials are products of a process for preparing ethanol from dimethyl ether, and comprise methanol, ethanol, methyl acetate, ethyl acetate, heavy component A, butene, water and light component A;
the heavy component A comprises propanol and acetic acid;
the light component A comprises dimethyl ether, nitrogen and argon.
The raw materials are derived from ethanol products prepared by dimethyl ether carbonylation and methyl acetate hydrogenation.
The technical scheme of the application comprises the following two systems: (1) a rectification separation system; (2) ethanol dehydration system. And the rectifying and separating system separates the reaction product of preparing ethanol from dimethyl ether to obtain hydrous ethanol, and recovers the mixture of methanol, ethyl acetate and methyl acetate, non-condensable gas, heavy alcohol and the like. The methanol, ethyl acetate and methyl acetate mixture is recovered and returned to the upstream system. The absolute ethanol product and the alcohol-containing wastewater are obtained by the ethanol dehydration system of the absolute ethanol. The separation process enables hydrogenation products to be fully separated, and high-purity absolute ethyl alcohol products are obtained, and other separated matters meet the circulation requirements or emission standards.
As a specific embodiment, the process method comprises the following steps:
the first rectifying tower is a light component removing tower; the second rectifying tower is an ethanol tower; the third rectifying tower is a heavy-removal tower; the fourth rectifying tower is a methanol tower;
firstly, a reaction product of preparing ethanol by dimethyl ether carbonylation hydrogenation passes through a light component removing tower, noncondensable gas at the top of the tower is discharged to a torch system, a mixture of methanol and ester in a reflux tank returns to an upstream reaction system, and a material at the bottom of the tower is removed to the ethanol tower; separating methanol, methyl acetate and ethyl acetate from the top of the ethanol tower, removing the heavy materials from the bottom of the tower, and removing the ethanol dehydration system from the side line to obtain an absolute ethanol product; recovering the residual ethanol from the top of the heavy-removal tower, and extracting heavy alcohol from the bottom of the heavy-removal tower; the mixture of methanol, methyl acetate and ethyl acetate extracted from the top of the methanol tower is returned to the upstream reaction system, trace ethanol recovered from the bottom of the methanol tower is returned to the ethanol tower, and high-concentration methanol extracted from the side line is returned to the upstream methanol dehydration unit.
As another embodiment, the process method includes:
firstly, the ethanol raw material passes through a light component removal tower, light components such as dimethyl ether and the like are removed from the tower top and returned to an upstream reaction system, and the tower bottom material is removed from the ethanol tower; all methyl acetate, ethyl acetate and methanol are extracted from the top of the ethanol tower, a part of ethanol and water ethanol dehydration system is extracted from the side line, and the rest of ethanol and heavy alcohol dehydration tower is extracted from the bottom of the ethanol tower; the ethanol recovery and ethanol removal dehydration system is extracted from the top of the heavy-duty removal tower, and the bottom of the heavy-duty removal tower is heavy alcohol; and (3) returning part of the mixture of methanol, methyl acetate and ethyl acetate extracted from the top of the methanol tower to an upstream reaction system, recovering methanol products by side extraction, and returning a small amount of recovered methanol and trace ethanol to the bottom of the methanol tower.
The gas phase containing the light component A comprises the light component A, methanol and methyl acetate;
preferably, the heavy component material I comprises methanol, ethanol, methyl acetate, ethyl acetate, heavy components, butene and water;
the heavy component material II comprises ethanol and a heavy component A;
the heavy component B comprises a heavy component A, and a small amount of ethanol is also included in the heavy component B.
The azeotrope II containing methanol, methyl acetate and ethyl acetate contains a small amount of unseparated methanol.
Optionally, in the step (3), the heavy component material II enters a third rectifying tower, and a gas phase component I is obtained after rectifying and separating;
the gas phase component I respectively enters a heat exchange device I-1 and a heat exchange device I-2 for heat exchange, and the gas phase quantity of the gas phase component I entering the heat exchange device I-1 is Q 1 The gas phase quantity of the gas phase component I entering the heat exchange device I-2 is Q 2 ，Q 1 +Q 2 =1, where Q 1 30 to70％，Q 2 30-70%;
the heat exchange device I-1 is connected with the first rectifying tower;
the heat exchange device I-2 is connected with the second rectifying tower;
the gas phase component I comprises ethanol and water.
Optionally, in the step (3), the azeotrope I containing methanol, methyl acetate and ethyl acetate enters a fourth rectifying tower, and a gas phase component II is obtained after rectification separation;
the gas phase component II enters a heat exchange device I-3 for heat exchange;
the heat exchange device I-3 is connected with the second rectifying tower;
the gas phase component II comprises methyl acetate, ethyl acetate and methanol.
Optionally, the absolute ethyl alcohol obtained by dehydration in the step (3) is mixed with the absolute ethyl alcohol obtained by dehydration in the step (4), and is discharged after heat exchange by a heat exchange device II-1;
and the heat exchange device II-1 is connected with the fourth rectifying tower.
As a specific embodiment, the process method comprises the following steps:
the first rectifying tower is a light component removing tower; the second rectifying tower is an ethanol tower; the third rectifying tower is a heavy-removal tower; the fourth rectifying tower is a methanol tower;
the gas at the top of the heavy removal tower provides a secondary heat source for a reboiler (a heat exchange device I-1) of the light removal tower, the gas at the top of the methanol tower and the partial gas at the top of the heavy removal tower provide secondary heat sources for a reboiler (a heat exchange device I-2 and a heat exchange device I-3) of the ethanol tower, and the high-temperature ethanol gas obtained by an ethanol dehydration system provides secondary heat sources for a heat exchange device II-1 of the methanol tower.
Optionally, the first rectifying tower, the second rectifying tower, the third rectifying tower and the fourth rectifying tower can be independently selected from a packing type rectifying tower or a tray type rectifying tower;
optionally, the reflux ratio of the first rectifying tower is 5-10;
alternatively, the upper limit of the reflux ratio of the first rectifying tower can be independently selected from 6.5, 8 and 10, and the lower limit can be independently selected from 5, 6.5 and 8;
optionally, the reflux ratio of the second rectifying tower is 2-8;
optionally, the upper limit of the reflux ratio of the second rectifying tower can be independently selected from 3, 5, 6 and 8, and the lower limit can be independently selected from 2, 3, 5 and 6;
optionally, the reflux ratio of the third rectifying tower is 4-12;
optionally, the upper limit of the reflux ratio of the third rectifying tower can be independently selected from 6, 9 and 12, and the lower limit can be independently selected from 4, 6 and 9;
optionally, the reflux ratio of the fourth rectifying tower is 60-90;
optionally, the upper limit of the reflux ratio of the fourth rectifying tower can be independently selected from 70, 80 and 90, and the lower limit can be independently selected from 60, 70 and 80;
optionally, in the raw materials, the weight content of methanol is 20-80%, the weight content of ethanol is 20-80%, the total weight content of methyl acetate and ethyl acetate is less than 5%, the weight content of water is less than 1%, the weight content of heavy components is less than 0.5%, and the weight content of light components is less than 0.5%.
Optionally, in the step (3), the purity of the methanol obtained after rectification separation is more than or equal to 99wt%;
optionally, the purity of the absolute ethyl alcohol is more than or equal to 99.5wt%.
Optionally, the operation pressure of the first rectifying tower is 40-500 kPa, and the operation temperature is 30-90 ℃;
alternatively, the upper limit of the operating pressure of the first rectifying column may be independently selected from 100kPa, 200kPa, 300kPa, 500kPa, and the lower limit may be independently selected from 40kPa, 100kPa, 200kPa, 300kPa;
alternatively, the upper operating temperature limit of the first rectifying column may be independently selected from 40 ℃, 50 ℃, 70 ℃, 90 ℃; the lower limit can be independently selected from 30deg.C, 40deg.C, 50deg.C, 70deg.C;
optionally, the operating pressure of the second rectifying tower is 20-500 kPa, and the operating temperature is 30-100 ℃;
alternatively, the upper operating pressure limit of the second rectification column may be independently selected from 100kPa, 200kPa, 300kPa, 500kPa; the lower limit may be independently selected from 20kPa, 100kPa, 200kPa, 300kPa;
alternatively, the upper operating temperature limit of the second rectification column may be independently selected from 50 ℃, 70 ℃, 100 ℃; the lower limit can be independently selected from 30deg.C, 50deg.C, 70deg.C;
optionally, the operating pressure of the third rectifying tower is 300-1000 kPa, and the operating temperature is 80-140 ℃;
alternatively, the upper operating pressure limit of the third rectification column may be independently selected from 500kPa, 700kPa, 1000kPa; the lower limit may be independently selected from 300kPa, 500kPa, 700kPa;
alternatively, the upper operating temperature limit of the third rectification column may be independently selected from 100 ℃, 110 ℃, 130 ℃, 140 ℃; the lower limit can be independently selected from 80 ℃, 100 ℃, 110 ℃ and 130 ℃;
optionally, the operating pressure of the fourth rectifying tower is 300-1000 kPa, and the operating temperature is 80-140 ℃;
alternatively, the upper limit of the fourth rectification column operating pressure may be independently selected from 500kPa, 700kPa, 1000kPa; the lower limit may be independently selected from 300kPa, 500kPa, 700kPa;
alternatively, the upper operating temperature limit of the fourth rectification column may be independently selected from 100 ℃, 110 ℃, 130 ℃, 140 ℃; the lower limit can be independently selected from 80 ℃, 100 ℃, 110 ℃ and 130 ℃;
optionally, the ethanol dehydration unit adopts a molecular sieve adsorption water analysis method or a membrane separation method to dehydrate to obtain the absolute ethanol.
The beneficial effects that this application can produce include:
the application provides a high-efficiency energy-saving separation process for separating an ethanol product in coal-based ethanol (dimethyl ether route) for the first time, so as to obtain an absolute ethanol product, and simultaneously obtain recycled methanol, a mixture of methyl acetate and ethyl acetate, noncondensable gas, heavy alcohol and the like. The process is thorough in separation, the intermediate product can be recycled, and the process technology of double-effect rectification is adopted while the anhydrous ethanol product with high concentration and high recovery rate is realized, so that the process production energy consumption is saved to the greatest extent.
Drawings
Fig. 1 is a schematic diagram of the ethanol product separation process in coal-based ethanol (dimethyl ether route) in example 1 of the present application.
Wherein:
t1, a light component removing tower; t2, an ethanol tower; t3, a heavy-duty removing tower; t4, a methanol tower; PU, ethanol dehydration unit; h, a reflux device; 1, raw materials; 2, non-condensable gas; 3, a mixture of methyl acetate and dimethyl ether; 4, methanol containing ester; 5, aqueous ethanol; 6, ethanol and heavy alcohol mixture; 7, heavy component products; 8, methanol; 9, steam; 10. absolute ethyl alcohol.
Detailed Description
The present application is described in detail below with reference to examples, but the present application is not limited to these examples.
Unless otherwise indicated, all starting materials in the examples of the present application were purchased commercially.
While specific embodiments of the invention are shown in the drawings, it is to be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the disclosure. Any person skilled in the art, using the disclosure above, may make alterations or modifications to the equivalent embodiments, which are still within the scope of the technical solution of the present invention. These embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. It should be further noted that, for convenience of description, only a portion relevant to the present disclosure is shown in the drawings.
Example 1
The flow and composition of the raw materials are as follows: flow 62t/h, typical material composition (wt%): 41% of methanol, 52% of ethanol, 3% of methyl acetate, 2% of ethyl acetate, 1% of water, 0.5% of propanol and other heavy components, and 0.5% of dimethyl ether and other light components. As in the process flow of FIG. 1, after the heat exchange between the raw materials and the products is raised to 81 ℃, the raw materials and the products enter a light component removal tower T1 to remove light components in crude alcohol and separate azeotropes of methyl acetate and methanol. The bottom material is sent to an ethanol tower T2.
Ethanol column T2 separates ethanol, methanol, and the azeotrope of methanol and crude ester. The azeotrope extracted from the top of the tower is sent to a methanol tower T4, the aqueous ethanol is extracted from the side line, the aqueous ethanol is sent to an ethanol dehydration device under pressure, the absolute ethanol is sent out of a boundary region after the residual heat is recovered, and the tower bottom material is sent to a de-weight tower T3.
The heavy alcohol in the ethanol is removed by the heavy alcohol removing tower T3. Ethanol extracted from the top of the tower is pressurized and sent into an ethanol dehydration device. And cooling the heavy alcohol extracted from the bottom of the tower and then pressurizing and delivering the cooled heavy alcohol out of the device.
The azeotrope of methanol and ester is separated from the top of the methanol tower T4. And separating refined methanol product from the side line. The crude alcohol extracted from the bottom of the tower is returned to the ethanol tower T2.
Two reboilers are arranged at the bottom of the light component removal tower T1, and one reboiler (heat exchange device I-1) provides a heat source for the gas extracted from the top of the heavy component removal tower T3.
Two reboilers are arranged at the bottom of the ethanol tower T2, wherein one reboiler (heat exchange device I-3) utilizes gas discharged from the top of the methanol tower T4 to provide a heat source for the reboiler, and the other reboiler (heat exchange device I-2) utilizes part of gas discharged from the top of the T3-heavy removal tower to provide a heat source for the reboiler.
A reboiler is arranged at the bottom of the heavy-removal tower T3, and an external heat source is used.
Two reboilers are arranged at the bottom of the methanol tower T4, wherein one reboiler (a heat exchange device II-1) provides a heat source for the dehydrated product absolute ethyl alcohol by using the ethanol dehydration unit, and the other reboiler uses an external heat source.
Separation requirements: the purity of the methanol is more than or equal to 99 weight percent.
The purity of the absolute ethyl alcohol is more than or equal to 99.5wt%.
The design and operation parameters of each tower of the rectification system are shown in table 1, and the total heat load of the external heat supply source is 48.72MW:
TABLE 1
| Column name | T1 | T2 | T3 | T4 |
| Tower heat load (MW) | 9.52 | 44.94 | 30.87 | 24.53 |
| External heat supply load (MW) | 0 | 0 | 30.87 | 17.85 |
| Reflux ratio | 6.5 | 4.8 | 9.5 | 60 |
| Column operating pressure (MPaG) | 0.07 | 0.07 | 0.18 | 0.4 |
| Column operating temperature (. Degree. C.) | 73 | 78 | 107 | 110 |
Example 2
The flow and composition of the raw materials are as follows: flow 62t/h, typical material composition (wt%): 57% of methanol, 35% of ethanol, 3% of methyl acetate, 2% of ethyl acetate, 1% of water, 0.5% of heavy alcohols such as propanol and the like, and 0.5% of light alcohols such as dimethyl ether and the like. As in the process flow of FIG. 1, after the temperature of the heat exchange between the raw materials and the product is raised to 81 ℃, the raw materials and the product enter a light component removal tower T1 to remove light components in crude alcohol and separate an azeotrope of methyl acetate and methanol. The bottom material is sent to an ethanol tower T2.
The ethanol tower T2 separates the ethanol, the methanol and the azeotrope of the methanol and the crude ester, the azeotrope is taken from the tower top and sent to the methanol tower T4, the aqueous ethanol is taken from the side line, the aqueous ethanol is pressurized and sent to the ethanol dehydration device, the absolute ethanol is sent out of the boundary region after the residual heat is recovered, and the tower bottom material is sent to the heavy-removal tower T3.
The heavy alcohol in the ethanol is removed by the heavy alcohol removal tower T3, and the ethanol extracted from the tower top is pressurized and sent into an ethanol dehydration device. And cooling the heavy alcohol extracted from the bottom of the tower and then pressurizing and delivering the cooled heavy alcohol out of the device.
The azeotrope of methanol and ester is separated from the top of the methanol tower T4. And separating refined methanol product from the side line. The crude alcohol extracted from the bottom of the tower is returned to the ethanol tower T2.
Two reboilers are arranged at the bottom of the light component removal tower T1, and one reboiler (heat exchange device I-1) provides a heat source for the gas extracted from the top of the heavy component removal tower T3.
Two reboilers are arranged at the bottom of the ethanol tower T2, wherein one reboiler (heat exchange device I-3) utilizes gas discharged from the top of the methanol tower T4 to provide a heat source for the reboiler, and the other reboiler (heat exchange device I-2) utilizes part of gas discharged from the top of the T3-heavy removal tower to provide a heat source for the reboiler.
A reboiler is arranged at the bottom of the heavy-removal tower T3, and an external heat source is used.
Two reboilers are arranged at the bottom of the methanol tower T4, wherein one reboiler (a heat exchange device II-1) provides a heat source for the dehydrated product absolute ethyl alcohol by using the ethanol dehydration unit, and the other reboiler uses an external heat source.
Separation requirements: the purity of the methanol is more than or equal to 99 weight percent.
The purity of the absolute ethyl alcohol is more than or equal to 99.5wt%.
The design and operating parameters of each tower of the rectification system are shown in Table 2, and the total heat load of the external heat supply source is 57.32MW:
TABLE 2
| Tower position number | T1 | T2 | T3 | T4 |
| Tower heat load (MW) | 10.8 | 49.87 | 28.62 | 33.41 |
| External heat supply load (MW) | 0 | 0 | 28.62 | 28.7 |
| Reflux ratio | 6.5 | 4.8 | 9.5 | 60 |
| Column operating pressure (MPaG) | 0.07 | 0.07 | 0.18 | 0.4 |
| Column operating temperature (. Degree. C.) | 73 | 78 | 107 | 110 |
Example 3
The flow and composition of the raw materials are as follows: flow 62t/h, typical material composition (wt%): 41% of methanol, 52% of ethanol, 3% of methyl acetate, 2% of ethyl acetate, 1% of water, 0.5% of propanol and other heavy components, and 0.5% of dimethyl ether and other light components. As in the process flow of FIG. 1, after the heat exchange between the raw materials and the products is raised to 81 ℃, the raw materials and the products enter a light component removal tower T1 to remove light components in crude alcohol and separate azeotropes of methyl acetate and methanol. The bottom material is sent to an ethanol tower T2.
The ethanol tower T2 separates the ethanol, the methanol and the azeotrope of the methanol and the crude ester, the azeotrope is taken from the tower top and sent to the methanol tower T4, the aqueous ethanol is taken from the side line, the aqueous ethanol is pressurized and sent to the ethanol dehydration device, the absolute ethanol is sent out of the boundary region after the residual heat is recovered, and the tower bottom material is sent to the heavy-removal tower T3.
The heavy alcohol in the ethanol is removed by the heavy alcohol removal tower T3, and the ethanol extracted from the tower top is pressurized and sent into an ethanol dehydration device. And cooling the heavy alcohol extracted from the bottom of the tower and then pressurizing and delivering the cooled heavy alcohol out of the device.
The azeotrope of methanol and ester is separated from the top of the methanol tower T4, and the refined methanol product is separated from the side line. The crude alcohol extracted from the bottom of the tower is returned to the ethanol tower T2.
Two reboilers are arranged at the bottom of the light component removal tower T1, and one reboiler (heat exchange device I-1) provides a heat source for the gas extracted from the top of the heavy component removal tower T3.
Two reboilers are arranged at the bottom of the ethanol tower T2, wherein one reboiler (heat exchange device I-3) utilizes gas discharged from the top of the methanol tower T4 to provide a heat source for the reboiler, and the other reboiler (heat exchange device I-2) utilizes part of gas discharged from the top of the T3-heavy removal tower to provide a heat source for the reboiler.
A reboiler is arranged at the bottom of the heavy-removal tower T3, and an external heat source is used.
Two reboilers are arranged at the bottom of the methanol tower T4, wherein one reboiler (a heat exchange device II-1) provides a heat source for the dehydrated product absolute ethyl alcohol by using the ethanol dehydration unit, and the other reboiler uses an external heat source.
Separation requirements: the purity of the methanol is more than or equal to 99 weight percent.
The purity of the absolute ethyl alcohol is more than or equal to 99.5wt%.
The design and operating parameters of each tower of the rectification system are shown in Table 3, and the total heat load of the external heat supply source is 35.4MW:
TABLE 3 Table 3
| Column name | T1 | T2 | T3 | T4 |
| Tower heat load (MW) | 9.52 | 30.43 | 20.11 | 21.93 |
| External heat supply load (MW) | 0 | 0 | 20.11 | 15.29 |
| Reflux ratio | 6.5 | 2.82 | 4.27 | 61.8 |
| Column operating pressure (MPaG) | 0.07 | -0.076 | 0.13 | 0.28 |
| Column operating temperature (. Degree. C.) | 73 | 33 | 101 | 101 |
In the embodiment 1, the embodiment 2 and the embodiment 3, four rectifying towers and an ethanol dehydration device are adopted to separate a crude ethanol product in the process of preparing the ethanol from the dimethyl ether, different feed compositions and pressure schemes are adopted in the embodiment, and the absolute ethanol product is obtained.
The foregoing description is only a few examples of the present application and is not intended to limit the present application in any way, and although the present application is disclosed in the preferred examples, it is not intended to limit the present application, and any person skilled in the art may make some changes or modifications to the disclosed technology without departing from the scope of the technical solution of the present application, and the technical solution is equivalent to the equivalent embodiments.
Claims (10)
1. A process method for separating coal-based ethanol, which is characterized by comprising the following steps:
(1) The raw materials are subjected to rectification separation in a first rectifying tower to obtain a gas phase containing a light component A and a heavy component material I;
(2) The heavy component material I enters a second rectifying tower, and an azeotrope I containing methanol, methyl acetate and ethyl acetate, an aqueous ethanol I and a heavy component material II are obtained after rectification and separation;
(3) The heavy component material II enters a third rectifying tower and is subjected to rectification separation to obtain hydrous ethanol II and heavy component B;
the azeotrope I containing methanol, methyl acetate and ethyl acetate enters a fourth rectifying tower, and is subjected to rectification separation to obtain a mixture containing methanol and ethanol and an azeotrope II containing methanol, methyl acetate and ethyl acetate;
the aqueous ethanol I enters an ethanol dehydration unit and is dehydrated to obtain absolute ethanol;
(4) The hydrous ethanol II enters an ethanol dehydration unit and is dehydrated to obtain absolute ethanol;
the mixture containing the ethanol enters a second rectifying tower and is mixed with a heavy component material I, and the step (2) is repeated;
wherein the raw materials are products of a process for preparing ethanol from dimethyl ether, and comprise methanol, ethanol, methyl acetate, ethyl acetate, heavy component A, butene, water and light component A;
the heavy component A comprises propanol and acetic acid;
the light component A comprises dimethyl ether, nitrogen and argon.
2. The process according to claim 1, wherein,
the gas phase containing the light component A comprises the light component A, methanol and methyl acetate;
preferably, the heavy component material I comprises methanol, ethanol, methyl acetate, ethyl acetate, heavy components, butene and water;
the heavy component material II comprises ethanol and a heavy component A;
the heavy component B comprises a heavy component A.
3. The process according to claim 1, wherein,
in the step (3), the heavy component material II enters a third rectifying tower and is subjected to rectifying separation to obtain a gas phase component I;
the gas phase component I respectively enters a heat exchange device I-1 and a heat exchange device I-2 for heat exchange, and the gas phase quantity of the gas phase component I entering the heat exchange device I-1 is Q 1 The gas phase quantity of the gas phase component I entering the heat exchange device I-2 is Q 2 ，Q 1 +Q 2 =1, where Q 1 30-70%, Q 2 30-70%;
the heat exchange device I-1 is connected with the first rectifying tower;
the heat exchange device I-2 is connected with the second rectifying tower;
preferably, the gas phase component I comprises ethanol and water;
preferably, in the step (3), the azeotrope I containing methanol, methyl acetate and ethyl acetate enters a fourth rectifying tower, and a gas phase component II is obtained after rectification separation;
the gas phase component II enters a heat exchange device I-3 for heat exchange;
the heat exchange device I-3 is connected with the second rectifying tower;
preferably, the gas phase component II comprises methyl acetate, ethyl acetate and methanol.
4. The process according to claim 1, wherein,
the absolute ethyl alcohol obtained by dehydration in the step (3) is mixed with the absolute ethyl alcohol obtained by dehydration in the step (4), and is discharged after heat exchange by a heat exchange device II-1;
and the heat exchange device II-1 is connected with the fourth rectifying tower.
5. The process according to claim 1, wherein,
the first rectifying tower, the second rectifying tower, the third rectifying tower and the fourth rectifying tower can be independently selected from a packing type rectifying tower or a tray type rectifying tower.
6. The process according to claim 1, wherein,
the reflux ratio of the first rectifying tower is 5-10;
preferably, the reflux ratio of the second rectifying tower is 2-8;
preferably, the reflux ratio of the third rectifying tower is 4-12;
preferably, the reflux ratio of the fourth rectifying tower is 60 to 90.
7. The process according to claim 1, wherein,
in the raw materials, the weight content of methanol is 20-80%, the weight content of ethanol is 20-80%, the total weight content of methyl acetate and ethyl acetate is less than 5%, the weight content of water is less than 1%, the weight content of heavy components is less than 0.5%, and the weight content of light components is less than 0.5%.
8. The process according to claim 1, wherein,
in the step (3), the purity of the methanol obtained after rectification separation is more than or equal to 99wt percent;
preferably, the purity of the absolute ethyl alcohol is more than or equal to 99.5wt%.
9. The process according to claim 1, wherein,
the operation pressure of the first rectifying tower is 40-500 kPa, and the operation temperature is 30-90 ℃;
the operating pressure of the second rectifying tower is 20-500 kPa, and the operating temperature is 30-100 ℃;
the operating pressure of the third rectifying tower is 300-1000 kPa, and the operating temperature is 80-140 ℃;
the operating pressure of the fourth rectifying tower is 300-1000 kPa, and the operating temperature is 80-140 ℃.
10. The process according to claim 1, wherein,
the ethanol dehydration unit adopts a molecular sieve adsorption water analysis method or a membrane separation method to dehydrate to obtain absolute ethanol.
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Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20120277496A1 (en) * | 2011-04-26 | 2012-11-01 | Celanese International Corporation | Process for Producing Ethanol and Reducing Acetic Acid Concentration |
| CN104649862A (en) * | 2015-02-05 | 2015-05-27 | 天津大学 | Method and equipment for producing ethanol product by taking ethyl acetate as raw material |
| CN109503326A (en) * | 2018-11-30 | 2019-03-22 | 西南化工研究设计院有限公司 | A kind of technique that dimethyl ether produces ethyl alcohol indirectly |
| CN111377800A (en) * | 2020-03-16 | 2020-07-07 | 中国科学院过程工程研究所 | Separation device and separation method for coal-to-ethanol liquid-phase product |
| CN212199065U (en) * | 2020-03-16 | 2020-12-22 | 中国科学院过程工程研究所 | Separation device for coal-to-ethanol liquid-phase product |
-
2021
- 2021-12-29 CN CN202111643580.2A patent/CN116410058A/en active Pending
Patent Citations (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20120277496A1 (en) * | 2011-04-26 | 2012-11-01 | Celanese International Corporation | Process for Producing Ethanol and Reducing Acetic Acid Concentration |
| CN104649862A (en) * | 2015-02-05 | 2015-05-27 | 天津大学 | Method and equipment for producing ethanol product by taking ethyl acetate as raw material |
| CN109503326A (en) * | 2018-11-30 | 2019-03-22 | 西南化工研究设计院有限公司 | A kind of technique that dimethyl ether produces ethyl alcohol indirectly |
| CN111377800A (en) * | 2020-03-16 | 2020-07-07 | 中国科学院过程工程研究所 | Separation device and separation method for coal-to-ethanol liquid-phase product |
| CN212199065U (en) * | 2020-03-16 | 2020-12-22 | 中国科学院过程工程研究所 | Separation device for coal-to-ethanol liquid-phase product |
Non-Patent Citations (1)
| Title |
|---|
| 韩飞;: "一种三塔差压分离燃料乙醇工艺流程的模拟计算", 化工与医药工程, no. 05, 15 October 2017 (2017-10-15), pages 15 - 19 * |
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