CN116410050A - CO (carbon monoxide) 2 Process method for preparing methyl styrene by dehydrogenation of methyl ethylbenzene oxide - Google Patents
CO (carbon monoxide) 2 Process method for preparing methyl styrene by dehydrogenation of methyl ethylbenzene oxide Download PDFInfo
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- CN116410050A CN116410050A CN202310308302.4A CN202310308302A CN116410050A CN 116410050 A CN116410050 A CN 116410050A CN 202310308302 A CN202310308302 A CN 202310308302A CN 116410050 A CN116410050 A CN 116410050A
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- JLBJTVDPSNHSKJ-UHFFFAOYSA-N 4-Methylstyrene Chemical compound CC1=CC=C(C=C)C=C1 JLBJTVDPSNHSKJ-UHFFFAOYSA-N 0.000 title claims abstract description 51
- 238000000034 method Methods 0.000 title claims abstract description 34
- 230000008569 process Effects 0.000 title claims abstract description 25
- 238000006356 dehydrogenation reaction Methods 0.000 title claims abstract description 23
- 229910002091 carbon monoxide Inorganic materials 0.000 title description 8
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 title description 4
- -1 methyl ethylbenzene oxide Chemical compound 0.000 title description 2
- HYFLWBNQFMXCPA-UHFFFAOYSA-N 1-ethyl-2-methylbenzene Chemical compound CCC1=CC=CC=C1C HYFLWBNQFMXCPA-UHFFFAOYSA-N 0.000 claims abstract description 74
- 239000007788 liquid Substances 0.000 claims abstract description 34
- 238000006243 chemical reaction Methods 0.000 claims abstract description 33
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 33
- 239000000463 material Substances 0.000 claims abstract description 10
- 238000004064 recycling Methods 0.000 claims abstract description 9
- 238000000926 separation method Methods 0.000 claims abstract description 9
- 239000012535 impurity Substances 0.000 claims abstract description 4
- 238000002156 mixing Methods 0.000 claims abstract description 4
- 238000009834 vaporization Methods 0.000 claims abstract description 4
- 230000008016 vaporization Effects 0.000 claims abstract description 4
- 238000011084 recovery Methods 0.000 claims description 18
- 239000006200 vaporizer Substances 0.000 claims description 14
- 238000010438 heat treatment Methods 0.000 claims description 11
- 239000000203 mixture Substances 0.000 claims description 11
- 239000000047 product Substances 0.000 claims description 11
- 229920006395 saturated elastomer Polymers 0.000 claims description 11
- 239000007791 liquid phase Substances 0.000 claims description 9
- 239000006227 byproduct Substances 0.000 claims description 7
- 238000004519 manufacturing process Methods 0.000 claims description 7
- KVNYFPKFSJIPBJ-UHFFFAOYSA-N 1,2-diethylbenzene Chemical compound CCC1=CC=CC=C1CC KVNYFPKFSJIPBJ-UHFFFAOYSA-N 0.000 claims description 6
- 238000001816 cooling Methods 0.000 claims description 6
- 239000012071 phase Substances 0.000 claims description 6
- 239000002351 wastewater Substances 0.000 claims description 5
- JRLPEMVDPFPYPJ-UHFFFAOYSA-N 1-ethyl-4-methylbenzene Chemical compound CCC1=CC=C(C)C=C1 JRLPEMVDPFPYPJ-UHFFFAOYSA-N 0.000 claims description 3
- ZLCSFXXPPANWQY-UHFFFAOYSA-N 3-ethyltoluene Chemical compound CCC1=CC=CC(C)=C1 ZLCSFXXPPANWQY-UHFFFAOYSA-N 0.000 claims description 3
- 230000009471 action Effects 0.000 claims description 3
- 238000009835 boiling Methods 0.000 claims description 3
- 238000009833 condensation Methods 0.000 claims description 3
- 230000005494 condensation Effects 0.000 claims description 3
- 239000003317 industrial substance Substances 0.000 claims description 3
- 238000010992 reflux Methods 0.000 claims description 2
- 239000008234 soft water Substances 0.000 claims description 2
- 239000007789 gas Substances 0.000 abstract description 26
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 abstract description 8
- 229910052799 carbon Inorganic materials 0.000 abstract description 8
- 239000003054 catalyst Substances 0.000 abstract description 7
- 230000008021 deposition Effects 0.000 abstract description 6
- 239000005431 greenhouse gas Substances 0.000 abstract description 5
- 239000003973 paint Substances 0.000 abstract description 3
- 239000002994 raw material Substances 0.000 abstract description 2
- 230000009467 reduction Effects 0.000 abstract description 2
- 230000000052 comparative effect Effects 0.000 description 4
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 4
- 230000001502 supplementing effect Effects 0.000 description 4
- PPBRXRYQALVLMV-UHFFFAOYSA-N Styrene Chemical compound C=CC1=CC=CC=C1 PPBRXRYQALVLMV-UHFFFAOYSA-N 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 239000000446 fuel Substances 0.000 description 2
- 239000003345 natural gas Substances 0.000 description 2
- JZHGRUMIRATHIU-UHFFFAOYSA-N 1-ethenyl-3-methylbenzene Chemical compound CC1=CC=CC(C=C)=C1 JZHGRUMIRATHIU-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000010790 dilution Methods 0.000 description 1
- 239000012895 dilution Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 239000004033 plastic Substances 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C5/00—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms
- C07C5/42—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by dehydrogenation with a hydrogen acceptor
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C7/00—Purification; Separation; Use of additives
- C07C7/005—Processes comprising at least two steps in series
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C7/00—Purification; Separation; Use of additives
- C07C7/04—Purification; Separation; Use of additives by distillation
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C7/00—Purification; Separation; Use of additives
- C07C7/10—Purification; Separation; Use of additives by extraction, i.e. purification or separation of liquid hydrocarbons with the aid of liquids
-
- 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
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/10—Process efficiency
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Analytical Chemistry (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Water Supply & Treatment (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention discloses a CO 2 The technological process of preparing methyl styrene through dehydrogenation of methyl ethylbenzene includes S1: material mixing vaporization, S2: material reaction, S3: gas-liquid separation, S4: impurity separation, S5: purifying crude methyl styrene, and S6: heat recycling and S7: CO 2 Resource utilization, easy operation, CO utilization 2 Improves the equilibrium conversion rate of methyl-ethylbenzene dehydrogenation to prepare methyl styrene and simultaneously CO 2 And can also react with carbon deposition generated on the surface of the catalyst, eliminate carbon deposition and prolong the service life of the catalyst.The CO concentration in the reaction tail gas is higher, and the reaction tail gas can be used as raw materials for other devices, thereby realizing greenhouse gas CO 2 The resource utilization of the water-based paint and the pollution reduction.
Description
Technical Field
The invention relates to a CO 2 A process method for preparing methyl styrene by dehydrogenation of methyl ethylbenzene.
Background
The methyl styrene has ortho, meta and para isomers, and the meta and para methyl styrene can replace styrene and is used in producing resin, plastic, paint, etc.
Methyl styrene is usually prepared by dehydrogenation of methyl ethylbenzene at high temperature and low pressure, a certain amount of superheated steam is generally required to be added in the reaction process, and the addition of the steam can reduce methyl ethylbenzene partial pressure, improve the equilibrium conversion rate of the reaction, and can react with carbon deposition on the surface of a catalyst, eliminate carbon deposition and prolong the service life of the catalyst.
However, in order to provide the reaction temperature, a large amount of superheated steam needs to be added in the reaction process, the energy consumption is excessive when a large amount of superheated steam is added, and a large amount of oily condensate is discharged, so that the water treatment cost is increased, and the conversion rate of the finished product is reduced under the dilution effect of a large amount of steam, so that a need is needed to realize comprehensive utilization after recovery treatment of a small amount of water which can reduce the reaction temperature, improve the methyl-ethyl benzene conversion rate and produce byproducts, and realize the CO as a greenhouse gas 2 The technological process of preparing methyl styrene with methyl ethylbenzene dehydrogenation.
Disclosure of Invention
In order to solve the problems, the invention provides a CO 2 The technological process of preparing methyl styrene by methyl ethylbenzene dehydrogenation has easy operation and CO utilization 2 Improves the equilibrium conversion rate of methyl-ethylbenzene dehydrogenation to prepare methyl styrene and simultaneously CO 2 And can also react with carbon deposition generated on the surface of the catalyst, eliminate carbon deposition and prolong the service life of the catalyst. The CO concentration in the reaction tail gas is higher, and the reaction tail gas can be used as raw materials for other devices, thereby realizing greenhouse gas CO 2 The resource utilization of the water-based paint and the pollution reduction. The specific technical scheme is as follows:
CO (carbon monoxide) 2 A process for preparing methyl styrene by dehydrogenation of methyl ethylbenzene oxide includesThe method comprises the following steps:
s1: material mixing and vaporization: methyl ethyl benzene, recycle methyl ethyl benzene and CO 2 The water vapor enters a vaporizer together and is mixed and vaporized;
s2: and (3) material reaction: the mixture material vaporized in the step S1 enters a heating furnace to be overheated, the overheated gas is introduced into a reactor, and methyl ethyl benzene is dehydrogenated in the reactor to produce methyl styrene and CO 2 Is reduced to CO and produces water;
s3: gas-liquid separation: the mixed gas after reaction in the step S2 enters a steam generator after heat exchange by a heat exchanger, the mixed gas from the steam generator enters a liquid separating tank after cooling and condensation, the gas phase is separated from the upper end of the liquid separating tank, the wastewater discharged from the bottom of the liquid separating tank is sent to a treatment facility, and the upper liquid phase in the liquid separating tank is methyl ethylbenzene and methyl styrene mixture containing a small amount of light components;
s4: impurity separation: the upper liquid phase in the liquid separating tank in the step S3 enters a light component removing tower, and CO in the mixture is removed under the rectification action 2 The liquid phase at the bottom of the tower is sent to an methyl ethyl benzene recovery tower, high-purity methyl ethyl benzene extracted from the top of the methyl ethyl benzene recovery tower is returned to a vaporizer, and crude methyl styrene is extracted from the bottom of the methyl ethyl benzene recovery tower;
s5: purifying crude methyl styrene: delivering the crude methylstyrene in the step S4 to a negative pressure rectification device of a methylstyrene product tower, extracting the methylstyrene from the top of the methylstyrene product tower, and delivering high-boiling residues in the tower kettle as byproducts
S6: and (3) heat recycling: in the step S3, after the mixed gas exchanges heat through a heat exchanger, heat released by cooling the mixed gas generates saturated steam, and the saturated steam is used by a vaporizer and rectification;
S7：CO 2 and (3) recycling: the gas phase separated from the liquid separating tank in the step S3, wherein 0.2 to 10 percent of volume enters a gas separating device to separate CO 2 CO and H 2 CO and H 2 Delivering to downstream equipment to generate other industrial chemicals, pressurizing, heating and overheat residual gas by circulating gas compressor, and delivering it to reactor again to maintain diethylbenzene and CO in the reactor 2 Is of the mole of (2)Molar ratio.
Preferably, the methyl ethylbenzene in the step S1 is m-methyl ethylbenzene, p-methyl ethylbenzene or a mixture of both.
Preferably, the outlet temperature of the reactor is 500-650 ℃, and the superheated gas in the step S2 enters the reactor by adopting a method of multi-strand feeding or arranging a plurality of reactors;
wherein:
setting a plurality of reactors, namely introducing overheated gas into the reactors through a flow divider for reaction;
separated into methyl ethylbenzene, water vapor and CO in multiple feeds 2 In the top feed of the reactor, methyl ethylbenzene, steam, CO 2 The molar ratio of (2) is 1:0.2 to 5:1 to 15, the middle and lower parts of the reactor are supplemented with water vapor and CO 2 The molar ratio of (2) is 0-1:1.
Preferably, the steam generator in the step S3 can generate saturated steam of 0.2-0.5 Mpa for the vaporizer and the rectification system, and part of water used by the steam generator is from the wastewater discharged from the bottom of the liquid separating tank after the treatment in the step S3, and the insufficient part is supplemented by external soft water.
Preferably, in the step S4, the temperature of the top of the light component removing tower is 60-130 ℃ and the operating pressure is 10-80 kPa.
Preferably, in the step S4, the temperature of the top of the methyl ethyl benzene recovery tower is 80-140 ℃ and the operating pressure is 5-55 kPa.
Preferably, the reboiler heat sources of the light component removing tower, the methyl ethyl benzene recovery tower and the methyl styrene product tower in the step S4 and the step S5 preferably use saturated steam generated by a steam generator, and the overhead fraction of the methyl ethyl benzene recovery tower is pumped to a vaporizer by an overhead reflux pump.
Preferably, the method comprises the steps of, the temperature difference between the outlet temperature of the heating furnace and the outlet temperature of the reactor in the step S2 is 100-150 ℃.
Preferably, the liquid separating tank in the step S3 is a liquid separating tank with a high-efficiency demister type and a gas-liquid tangential inlet.
The beneficial effects of the invention are as follows:
1、CO 2 dehydrogenation of methyl ethylbenzene oxideThe equilibrium conversion rate of the catalyst is higher than that of the conventional steam-assisted methyl ethyl benzene dehydrogenation, and the whole process adopts CO 2 The dehydrogenation conversion rate of methyl ethyl benzene is improved together with water vapor, and the methyl ethyl benzene conversion rate is up to 70-95%;
2. the whole process adopts a step-by-step heat supplementing mode to ensure the temperature in the reactor, the process can reduce the water vapor consumption, the byproduct water is recycled to realize comprehensive utilization, and simultaneously, the methyl-ethylbenzene conversion rate can be improved to realize the greenhouse gas CO 2 Is used for recycling.
Drawings
FIG. 1 is an overall process flow diagram of an embodiment of the present invention;
FIG. 2 is an enlarged view of a portion of a first part of a process flow according to an embodiment of the invention;
FIG. 3 is an enlarged partial view of a second portion of a process flow according to an embodiment of the present invention;
fig. 4 is a partial enlarged view of a third portion of a process flow according to an embodiment of the invention.
Detailed Description
The technical scheme of the invention will be clearly and completely described below in connection with the specific embodiments:
CO (carbon monoxide) 2 The technological process of preparing methyl styrene through dehydrogenation of methyl ethylbenzene includes the following steps:
s1: material mixing and vaporization: methyl ethyl benzene, recycle methyl ethyl benzene and CO 2 The water vapor enters a vaporizer together and is mixed and vaporized;
s2: and (3) material reaction: the mixture material vaporized in the step S1 enters a heating furnace to be overheated, the overheated gas is introduced into a reactor, and methyl ethyl benzene is dehydrogenated in the reactor to produce methyl styrene and CO 2 Is reduced to CO and produces water;
s3: gas-liquid separation: the mixed gas after reaction in the step S2 enters a steam generator after heat exchange by a heat exchanger, the mixed gas from the steam generator enters a liquid separating tank after cooling and condensation, the gas phase is separated from the upper end of the liquid separating tank, the wastewater discharged from the bottom of the liquid separating tank is sent to a treatment facility, and the upper liquid phase in the liquid separating tank is methyl ethylbenzene and methyl styrene mixture containing a small amount of light components;
s4: impurity separation: the upper liquid phase in the liquid separating tank in the step S3 enters a light component removing tower, and CO in the mixture is removed under the rectification action 2 The liquid phase at the bottom of the tower is sent to an methyl ethyl benzene recovery tower, high-purity methyl ethyl benzene extracted from the top of the methyl ethyl benzene recovery tower is returned to a vaporizer, and crude methyl styrene is extracted from the bottom of the methyl ethyl benzene recovery tower;
s5: purifying crude methyl styrene: delivering the crude methylstyrene in the step S4 to a negative pressure rectification device of a methylstyrene product tower, extracting the methylstyrene from the top of the methylstyrene product tower, and delivering high-boiling residues in the tower kettle as byproducts
S6: and (3) heat recycling: in the step S3, after the mixed gas exchanges heat through a heat exchanger, heat released by cooling the mixed gas generates saturated steam, and the saturated steam is used by a vaporizer and rectification;
S7：CO 2 and (3) recycling: the gas phase separated from the liquid separating tank in the step S3, wherein 0.2 to 10 percent of volume enters a gas separating device to separate CO 2 CO and H 2 CO and H 2 Delivering to downstream equipment to generate other industrial chemicals, pressurizing, heating and overheat residual gas by circulating gas compressor, and delivering it to reactor again to maintain diethylbenzene and CO in the reactor 2 Molar ratio of (3).
Example 1
The specific process refers to the steps, wherein:
1. reactor with two feeds, as shown in the figure, methyl ethyl benzene, steam and CO in the top feed of the reactor 2 Molar of (2) the ratio is 1:1:8, supplementing water vapor and CO in the middle part of the reactor 2 The molar ratio of (2) is 0.1:1;
2. the outlet temperature of the reactor was controlled at 550℃and the reactor was operated at normal pressure with a liquid space velocity of 1.0h-1.
3. The heating furnace is preferably natural gas as fuel, and the temperature difference between the outlet temperature of the heating furnace and the outlet temperature of the reactor is 135 ℃.
4. The pressure of the steam generator is controlled to be 0.3Mpa, and the generated saturated steam is used by a vaporizer and a rectifying system.
5. The light component removing tower has a tower top temperature of 92 ℃, a condenser outlet temperature of 45 ℃ and a tower top operating pressure of 30kPa; the light component removing tower condenser adopts an integrated condenser.
6. Methyl ethyl benzene recovery tower, tower top temperature 100 deg.c and tower top operation pressure 20kPa.
7. The methyl styrene product column had a top temperature of 116℃and a top operating pressure of 20kPa.
Comparative example 1
By adopting the traditional production method, the molar ratio of water vapor to methyl ethyl benzene (water ratio) in the reactor feed is 2.5:1, and the molar ratio of the reduced water methyl ethyl benzene to the water vapor is 0.5:9.3;
2. controlling the outlet temperature of the reactor to 605 ℃, and operating the reactor under normal pressure; space velocity of liquid 0.5h -1 . The conversion, selectivity, yield, steam consumption, carbon deposit thickness, etc. for example one versus comparative example one are shown in the following table:
list one
Example 2
1. Reactor with two feeds, as shown in the figure, methyl ethyl benzene, steam and CO in the top feed of the reactor 2 The molar ratio of (2) is 1:0.5:6, supplementing water vapor and CO in the middle part of the reactor 2 The molar ratio of (2) is 0.1:1;
2. controlling the outlet temperature of the reactor to be 550 ℃, and operating the reactor under normal pressure; the liquid space velocity is 1.0h < -1 >.
3. The heating furnace is preferably natural gas as fuel, and the temperature difference between the outlet temperature of the heating furnace and the outlet temperature of the reactor is 150 ℃.
4. The light component removing tower has a tower top temperature of 111 ℃, a condenser outlet temperature of 45 ℃ and a tower top operating pressure of 50kPa.
5. Methyl ethyl benzene recovery tower, tower top temperature 120 deg.c and tower top operation pressure 30kPa.
6. The methyl styrene product column has a top temperature of 128 ℃ and a top operating pressure of 30kPa.
Comparative example 2
By adopting the traditional production method, the molar ratio of water vapor to methyl ethyl benzene (water ratio) in the reactor feed is 1.8:1, and the molar ratio of the reduced water methyl ethyl benzene to the water vapor is 0.4:7.9;
2. controlling the outlet temperature of the reactor to 605 ℃, and operating the reactor under normal pressure; space velocity of liquid 0.5h -1 The conversion, selectivity, yield, steam consumption, carbon deposit thickness, etc. for example two versus comparative example two are shown in the following table:
watch II
From the two tables, it can be clearly derived:
1、CO 2 the equilibrium conversion rate of methyl ethyl benzene dehydrogenation is higher than that of the conventional steam-assisted methyl ethyl benzene dehydrogenation, and the whole process adopts CO 2 The dehydrogenation conversion rate of methyl ethyl benzene is improved together with water vapor, and the methyl ethyl benzene conversion rate is up to 70-95%;
2. the whole process adopts a step-by-step heat supplementing mode to ensure the temperature in the reactor, the process can reduce the water vapor consumption, the byproduct water is recycled to realize comprehensive utilization, and simultaneously, the methyl-ethylbenzene conversion rate can be improved to realize the greenhouse gas CO 2 Is used for recycling.
Note that: because the process is complex, the process diagram is split into three parts for complete understanding, wherein the reference numerals are the same in the same route.
The foregoing has outlined and described the basic principles, features, and advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, and that the above embodiments and descriptions are merely illustrative of the principles of the present invention, and various changes and modifications may be made without departing from the spirit and scope of the invention, which is defined in the appended claims. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (9)
1. A process method for preparing methyl styrene by CO2 methyl ethylbenzene dehydrogenation is characterized by comprising the following steps: the method comprises the following steps:
s1: material mixing and vaporization: methyl ethyl benzene and circulating methyl ethyl benzene are fed into a vaporizer together with CO2 and water vapor, and are mixed and vaporized;
s2: and (3) material reaction: the vaporized mixture in the step S1 enters a heating furnace to be overheated, the overheated gas is introduced into a reactor, methyl ethyl benzene is dehydrogenated in the reactor to produce methyl styrene, CO2 is reduced into CO, and water is produced;
s3: gas-liquid separation: the mixed gas after reaction in the step S2 enters a steam generator after heat exchange by a heat exchanger, the mixed gas from the steam generator enters a liquid separating tank after cooling and condensation, the gas phase is separated from the upper end of the liquid separating tank, the wastewater discharged from the bottom of the liquid separating tank is sent to a treatment facility, and the upper liquid phase in the liquid separating tank is methyl ethylbenzene and methyl styrene mixture containing a small amount of light components;
s4: impurity separation: the upper liquid phase in the liquid separating tank in the step S3 enters a light component removing tower, CO2, water and byproduct light components in the mixture are removed under the rectification action, the bottom liquid phase is sent to a methyl ethyl benzene recovery tower, high-purity methyl ethyl benzene extracted from the top of the methyl ethyl benzene recovery tower returns to a vaporizer, and crude methyl styrene is extracted from the bottom of the methyl ethyl benzene recovery tower;
s5: purifying crude methyl styrene: delivering the crude methylstyrene in the step S4 to a negative pressure rectification device of a methylstyrene product tower, extracting the methylstyrene from the top of the methylstyrene product tower, and delivering high-boiling residues in the tower kettle as byproducts
S6: and (3) heat recycling: in the step S3, after the mixed gas exchanges heat through a heat exchanger, heat released by cooling the mixed gas generates saturated steam, and the saturated steam is used by a vaporizer and rectification;
s7: CO2 recycling: the gas phase separated by the liquid separating tank in the step S3, wherein 0.2-10% vol enters a gas separation device, CO2, CO and H2 are separated, the CO and H2 are sent to a downstream device to generate other industrial chemicals, and the residual gas enters a reactor again after being pressurized, heated and overheated by a circulating gas compressor, and diethylbenzene and CO in the reactor are maintained 2 Molar ratio of (3).
2. The CO according to claim 1 2 The technological process of preparing methyl styrene through dehydrogenation of methyl ethylbenzene is characterized by comprising the following steps: the methyl ethylbenzene in the step S1 is m-methyl ethylbenzene, p-methyl ethylbenzene or a mixture of the m-methyl ethylbenzene and the p-methyl ethylbenzene.
3. The CO according to claim 1 2 The technological process of preparing methyl styrene through dehydrogenation of methyl ethylbenzene is characterized by comprising the following steps: the outlet temperature of the reactor is 500-650 DEG C ， The superheated gas in the step S2 enters the reactors by adopting a method of feeding in multiple strands or arranging a plurality of reactors;
wherein:
setting a plurality of reactors, namely introducing overheated gas into the reactors through a flow divider for reaction;
separated into methyl ethylbenzene, water vapor and CO in multiple feeds 2 In the top feed of the reactor, methyl ethylbenzene, steam, CO 2 The molar ratio of (2) is 1:0.2 to 5:1 to 15, the middle and lower parts of the reactor are supplemented with water vapor and CO 2 The molar ratio of (2) is 0-1:1.
4. The CO according to claim 1 2 The technological process of preparing methyl styrene through dehydrogenation of methyl ethylbenzene is characterized by comprising the following steps: the steam generator in the step S3 can generate saturated steam of 0.2-0.5 Mpa for the vaporizer and the rectification system, and part of water used by the steam generator is from the wastewater discharged from the bottom of the liquid separating tank treated in the step S3, and the insufficient part is supplemented by external soft water.
5. According to claim 1Said CO 2 The technological process of preparing methyl styrene through dehydrogenation of methyl ethylbenzene is characterized by comprising the following steps: in the step S4, the temperature of the top of the light component removing tower is 60-130 ℃ and the operating pressure is 10-80 kPa.
6. The CO according to claim 1 2 The technological process of preparing methyl styrene through dehydrogenation of methyl ethylbenzene is characterized by comprising the following steps: in the step S4, the temperature of the top of the methyl ethyl benzene recovery tower is 80-140 ℃ and the operating pressure is 5-55 kPa.
7. The process for preparing methylstyrene by dehydrogenating methyl ethylbenzene CO2 as claimed in claim 1, wherein: the reboiler heat sources of the light component removing tower, the methyl ethyl benzene recovery tower and the methyl styrene product tower in the step S4 and the step S5 preferably use saturated steam generated by a steam generator, and the overhead fraction of the methyl ethyl benzene recovery tower is pumped to a vaporizer through an overhead reflux pump.
8. The process for preparing methylstyrene by dehydrogenating methyl ethylbenzene CO2 as claimed in claim 7, wherein: the temperature difference between the outlet temperature of the heating furnace and the outlet temperature of the reactor in the step S2 is 100-150 ℃.
9. The process for preparing methylstyrene by dehydrogenating methyl ethylbenzene CO2 as claimed in claim 1, wherein: the liquid separating tank in the step S3 is a gas-liquid tangential inlet and a liquid separating tank with a high-efficiency demister.
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| CN202310308302.4A CN116410050A (en) | 2023-03-27 | 2023-03-27 | CO (carbon monoxide) 2 Process method for preparing methyl styrene by dehydrogenation of methyl ethylbenzene oxide |
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| CN202310308302.4A CN116410050A (en) | 2023-03-27 | 2023-03-27 | CO (carbon monoxide) 2 Process method for preparing methyl styrene by dehydrogenation of methyl ethylbenzene oxide |
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