CN111574375B - Separation method and separation equipment for methyl acrylate crude product gas - Google Patents
Separation method and separation equipment for methyl acrylate crude product gas Download PDFInfo
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- BAPJBEWLBFYGME-UHFFFAOYSA-N Methyl acrylate Chemical compound COC(=O)C=C BAPJBEWLBFYGME-UHFFFAOYSA-N 0.000 title claims abstract description 258
- 239000012043 crude product Substances 0.000 title claims abstract description 66
- 238000000926 separation method Methods 0.000 title claims abstract description 53
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 claims abstract description 205
- 238000000605 extraction Methods 0.000 claims abstract description 165
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims abstract description 123
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 121
- 238000010533 azeotropic distillation Methods 0.000 claims abstract description 109
- 150000002148 esters Chemical class 0.000 claims abstract description 51
- 239000008098 formaldehyde solution Substances 0.000 claims abstract description 49
- 238000000034 method Methods 0.000 claims abstract description 24
- 239000003795 chemical substances by application Substances 0.000 claims abstract description 4
- 239000012071 phase Substances 0.000 claims description 107
- 238000010992 reflux Methods 0.000 claims description 78
- 239000007788 liquid Substances 0.000 claims description 35
- 238000001816 cooling Methods 0.000 claims description 31
- 238000000895 extractive distillation Methods 0.000 claims description 24
- 238000006243 chemical reaction Methods 0.000 claims description 18
- 238000004821 distillation Methods 0.000 claims description 17
- 239000000047 product Substances 0.000 claims description 15
- 239000000243 solution Substances 0.000 claims description 15
- RJUFJBKOKNCXHH-UHFFFAOYSA-N Methyl propionate Chemical group CCC(=O)OC RJUFJBKOKNCXHH-UHFFFAOYSA-N 0.000 claims description 14
- 238000005984 hydrogenation reaction Methods 0.000 claims description 12
- 229940017219 methyl propionate Drugs 0.000 claims description 11
- 238000011084 recovery Methods 0.000 claims description 11
- 230000008569 process Effects 0.000 claims description 10
- 239000002994 raw material Substances 0.000 claims description 9
- 230000006835 compression Effects 0.000 claims description 8
- 238000007906 compression Methods 0.000 claims description 8
- 239000007864 aqueous solution Substances 0.000 claims description 7
- 239000002904 solvent Substances 0.000 claims description 7
- 238000009835 boiling Methods 0.000 claims description 5
- 238000004064 recycling Methods 0.000 claims description 5
- MGJURKDLIJVDEO-UHFFFAOYSA-N formaldehyde;hydrate Chemical compound O.O=C MGJURKDLIJVDEO-UHFFFAOYSA-N 0.000 claims description 4
- BHIWKHZACMWKOJ-UHFFFAOYSA-N methyl isobutyrate Chemical compound COC(=O)C(C)C BHIWKHZACMWKOJ-UHFFFAOYSA-N 0.000 claims description 4
- 239000008346 aqueous phase Substances 0.000 claims description 2
- WDAXFOBOLVPGLV-UHFFFAOYSA-N isobutyric acid ethyl ester Natural products CCOC(=O)C(C)C WDAXFOBOLVPGLV-UHFFFAOYSA-N 0.000 claims description 2
- 238000005086 pumping Methods 0.000 claims description 2
- 238000005265 energy consumption Methods 0.000 abstract description 15
- 239000007789 gas Substances 0.000 description 149
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 27
- XBDQKXXYIPTUBI-UHFFFAOYSA-M Propionate Chemical compound CCC([O-])=O XBDQKXXYIPTUBI-UHFFFAOYSA-M 0.000 description 27
- KXKVLQRXCPHEJC-UHFFFAOYSA-N acetic acid trimethyl ester Natural products COC(C)=O KXKVLQRXCPHEJC-UHFFFAOYSA-N 0.000 description 27
- 239000003921 oil Substances 0.000 description 27
- 230000008878 coupling Effects 0.000 description 14
- 238000010168 coupling process Methods 0.000 description 14
- 238000005859 coupling reaction Methods 0.000 description 14
- 239000003245 coal Substances 0.000 description 9
- VVQNEPGJFQJSBK-UHFFFAOYSA-N Methyl methacrylate Chemical compound COC(=O)C(C)=C VVQNEPGJFQJSBK-UHFFFAOYSA-N 0.000 description 8
- WSFSSNUMVMOOMR-NJFSPNSNSA-N methanone Chemical compound O=[14CH2] WSFSSNUMVMOOMR-NJFSPNSNSA-N 0.000 description 8
- 238000010438 heat treatment Methods 0.000 description 6
- 239000012535 impurity Substances 0.000 description 6
- STNJBCKSHOAVAJ-UHFFFAOYSA-N Methacrolein Chemical compound CC(=C)C=O STNJBCKSHOAVAJ-UHFFFAOYSA-N 0.000 description 5
- 239000006227 byproduct Substances 0.000 description 5
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- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- 239000004372 Polyvinyl alcohol Substances 0.000 description 2
- KKEYFWRCBNTPAC-UHFFFAOYSA-N Terephthalic acid Chemical compound OC(=O)C1=CC=C(C(O)=O)C=C1 KKEYFWRCBNTPAC-UHFFFAOYSA-N 0.000 description 2
- 238000006136 alcoholysis reaction Methods 0.000 description 2
- 150000001299 aldehydes Chemical class 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
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- 229920002451 polyvinyl alcohol Polymers 0.000 description 2
- QQONPFPTGQHPMA-UHFFFAOYSA-N propylene Natural products CC=C QQONPFPTGQHPMA-UHFFFAOYSA-N 0.000 description 2
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 2
- 238000000746 purification Methods 0.000 description 2
- 238000011160 research Methods 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000012546 transfer Methods 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/48—Separation; Purification; Stabilisation; Use of additives
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/48—Separation; Purification; Stabilisation; Use of additives
- C07C67/52—Separation; Purification; Stabilisation; Use of additives by change in the physical state, e.g. crystallisation
- C07C67/54—Separation; Purification; Stabilisation; Use of additives by change in the physical state, e.g. crystallisation by distillation
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C67/00—Preparation of carboxylic acid esters
- C07C67/48—Separation; Purification; Stabilisation; Use of additives
- C07C67/58—Separation; Purification; Stabilisation; Use of additives by liquid-liquid treatment
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Crystallography & Structural Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention provides a separation method and equipment of methyl acrylate crude product gas, wherein the method comprises the following steps: the methyl acrylate crude product gas is subjected to light removal treatment; carrying out azeotropic distillation treatment on the methyl acrylate crude product gas after the light removal to remove formaldehyde and heavy ester components; the tower top compressed steam of azeotropic distillation treatment is used as a reboiler heat source for light removal treatment; extracting and rectifying formaldehyde solution obtained by azeotropic rectification by adopting water to remove methanol components; extracting the formaldehyde solution after the extraction and rectification treatment by adopting a first extractant to extract the formaldehyde solution so as to remove heavy ester components in the formaldehyde solution, and extracting the oil phase by adopting a second extractant so as to remove formaldehyde; carrying out de-weight treatment on the oil phase obtained by the extraction treatment, and recovering light ester and water respectively as extracting agents of the extraction treatment; and (3) carrying out steam stripping treatment on the water phase obtained by the extraction treatment. The invention can obviously reduce the energy consumption of the device and the cost.
Description
Technical Field
The invention relates to the technical field of separation of an ester-aldehyde alcohol system, in particular to a separation method and separation equipment for preparing crude product gas of methyl acrylate from coal-based methyl acetate and formaldehyde.
Background
In both polyvinyl alcohol and terephthalic acid production processes, a significant amount of methyl acetate byproduct is produced. 1.6 tons of alcoholysis waste liquid of methyl acetate is produced as a byproduct for each 1 ton of polyvinyl alcohol, and the main components of the waste liquid are more than 75 percent of methyl acetate and less than 25 percent of methanol. Because methyl acetate and methanol can form an azeotrope, the methyl acetate is often required to be purified by a separation method with high energy consumption, long flow and high cost, but along with the fact that the methyl acetate and the methanol in China enter a serious excessive period, the economic benefit of separating the methyl acetate and the methanol from the alcoholysis waste liquid is not obvious, so that the economic benefit and the social benefit are good if the byproduct methyl acetate is directly converted into a high added value product without purification.
Methyl acrylate is an important synthetic intermediate and is also a monomer for synthesizing high-molecular polymers, and is widely applied to chemical fiber, textile, rubber, medicine, resin, papermaking, adhesive, coating, leather and other industries. At present, methyl acrylate is mainly prepared by a propylene oxidation method suitable for large-scale production, the propylene route method is seriously dependent on petroleum refining products, in recent years, the petroleum import amount in China is continuously increased, the external dependence is increased year by year, and the international crude oil market is complex and sensitive.
In addition, with the vigorous development of the coal chemical industry, the domestic mature coal-based route formaldehyde also has surplus productivity, so that the development of a route for synthesizing methyl acrylate from coal-based methyl acetate and formaldehyde has important significance.
In recent years, many scientific research units at home and abroad develop research work of synthesizing Methyl Acrylate (MA) by taking methyl acetate and formaldehyde as raw materials, and then preparing Methyl Propionate (MP) through methyl acrylate hydrogenation, thereby preparing Methyl Methacrylate (MMA) with high added value. The MA synthesis by taking methyl acetate and formaldehyde as raw materials and methanol as a solvent is the most critical step in the MMA technical route, and can be called as the bottleneck of preparing MMA from coal-based methyl acetate and formaldehyde. Since the crude product gas of methyl acrylate contains a small amount of impurities such as methacrolein, methyl propionate, methyl methacrylate, acetic acid, heavy esters and the like in addition to water produced by the main reaction, methanol as a solvent used in the reaction, and unreacted methyl acetate and formaldehyde. And MA is close to the boiling point of the impurities, or because MA and the impurities form a plurality of groups of azeotropic systems, the MA is difficult to recover high-purity MA from MA crude product gas by a traditional separation method, and in addition, the MA with high concentration is easy to polymerize, and unreacted formaldehyde is easy to polymerize at low temperature, so that the difficulty of separating and purifying MA crude product gas is increased. Therefore, a separation method of methyl acrylate crude product gas with low energy consumption, low investment and high recovery rate of each component is needed.
Disclosure of Invention
Aiming at the technical problems in the prior art, the invention provides a separation method and equipment for crude product gas of methyl acrylate (MA for short), which have the characteristic of low energy consumption.
In one aspect, the embodiment of the invention provides a separation method of methyl acrylate crude product gas, which comprises the following steps:
the methyl acrylate crude product gas is subjected to light removal treatment, and light components are recovered as raw materials;
carrying out azeotropic distillation treatment on the methyl acrylate crude product gas after the light removal to remove formaldehyde and heavy ester components; wherein, the gas phase at the top of the azeotropic distillation treatment is compressed and heated and then used as a reboiler heat source for the light removal treatment;
extracting and rectifying the formaldehyde solution obtained by azeotropic rectification by water to remove methanol components in the formaldehyde solution;
extracting formaldehyde solution from which methanol is removed by extractive distillation, wherein a first extractant is adopted to extract the formaldehyde solution so as to remove heavy ester components in the formaldehyde solution, and a second extractant is adopted to extract an oil phase so as to remove formaldehyde;
carrying out de-weight treatment on the oil phase obtained by the extraction treatment, and recovering light ester and water to be respectively used as the first extractant and the second extractant of the extraction treatment; the intermediate reboiler for the de-duplication treatment adopts the gas phase at the top of the tower for the de-duplication treatment as a heat source after being compressed and heated;
And (3) carrying out steam stripping treatment on the water phase obtained by the extraction treatment to recover the light ester component, thereby obtaining a tower bottom dilute formaldehyde water solution.
In some embodiments, the methyl acrylate raw product gas is subjected to a light ends treatment comprising:
cooling the crude product gas of methyl acrylate to a preset temperature, and enabling the crude product gas of methyl acrylate to enter a light component removing tower in a gas phase state for light component removing treatment;
cooling the top gas phase of the light component removal tower to a preset temperature by adopting an air cooler, entering a light component removal tower reflux tank, returning condensate in the light component removal tower reflux tank as reflux to the light component removal tower, and enabling the top gas phase component of the light component removal tower reflux tank to enter a light component removal tower top tank, wherein the condensate in the light component removal tower top tank is returned to the methyl acrylate reaction unit as a recovered light component;
the bottom liquid of the light component removal tower is subjected to azeotropic distillation after being pumped and pressurized.
In some embodiments, the azeotropic distillation of the stripped crude methyl acrylate gas comprises:
after the methyl acrylate crude product gas is subjected to light removal treatment, the crude product gas is sent to an azeotropic distillation tower for azeotropic distillation through pressure extraction;
after heat exchange of the tower top gas phase subjected to azeotropic distillation treatment is carried out by the reboiler of the light component removal tower, water is cooled to a preset temperature, and the water enters a reflux tank of the azeotropic distillation tower, wherein part of condensate in the reflux tank of the azeotropic distillation tower is returned to the azeotropic distillation tower as reflux, and the other part of condensate is sent to a downstream methyl acrylate hydrogenation unit;
The reboiler of the azeotropic distillation tower can adopt low-pressure steam as a heat source;
and extracting and rectifying tower bottom liquid of the azeotropic rectifying tower after pumping and pressurizing.
In some embodiments, the extractive distillation of the formaldehyde solution resulting from the azeotropic distillation with water comprises:
the formaldehyde solution obtained by azeotropic distillation is sent to an extraction distillation tower for extraction distillation treatment after being pressurized;
cooling the gas phase at the top of the extractive distillation column to a preset temperature by adopting an air cooler, wherein one part of the obtained condensate is used as reflux, and the other part of the condensate is used as a methanol solvent to return to the methyl acrylate reaction unit;
the reboiler of the extraction rectifying tower can adopt low-pressure steam as a heat source;
and cooling the formaldehyde-rich solution at the tower bottom of the extraction rectifying tower by circulating water, and extracting by a pump.
In some embodiments, the oil phase obtained by the extraction treatment is subjected to a de-duplication treatment, comprising:
the heavy ester-rich oil phase obtained from the extraction treatment enters a heavy-removal tower to remove heavy components in the oil phase, and an extracting agent is recovered;
after the temperature of the gas phase at the top of the heavy removal tower is increased by compression, the gas phase is used as a heat source of a boiling device in the heavy removal tower, the gas phase at the top of the heavy removal tower after heat exchange by the boiling device in the heavy removal tower is cooled to a preset temperature by water and then enters a reflux tank of the heavy removal tower for oil-water delamination, part of the boosted oil phase is used as reflux and returns to the bottom of the extraction tower, the other part of the boosted oil phase is used as a first extractant and returns to the top of the extraction tower as a second extractant;
The heavy-removal tower reboiler of the heavy-removal tower can adopt low-pressure steam as a heat source;
and (3) recycling the heavy components in the tower bottom of the heavy removal tower.
In some embodiments, the aqueous phase resulting from the extraction process is subjected to a stripping process comprising:
the dilute formaldehyde solution obtained from the extraction treatment enters a stripping tower to remove light ester components in the formaldehyde aqueous solution;
the gas phase at the top of the stripping tower is cooled to a preset temperature through circulating water, and the condensate is returned to the extraction tower after being boosted;
the stripping tower reboiler of the stripping tower can adopt low-pressure steam as a heat source, and the tower bottom liquid of the stripping tower is pumped and pressurized to remove the dilute formaldehyde recovery system.
In some embodiments, the azeotropic distillation treatment and the extractive distillation treatment are performed by using a baffle rectifying tower, a vertical baffle is arranged in the middle part of the baffle rectifying tower, the rectifying tower is divided into an upper public rectifying section, a lower public stripping section, a rectifying feeding section and a side extraction section on two sides of the baffle, the crude product gas of methyl acrylate after the light removal treatment and water serving as an extractant enter from the rectifying feeding section, and the rectifying feeding section plays the role of a primary fractionating tower to separate light components and heavy components; the separation of light components and intermediate components is realized in the public rectifying section, and the compressed and heated gas at the top of the tower is used as a heat source of a reboiler of the light component removal tower; the separation of intermediate components and heavy components is realized in the public stripping section, and formaldehyde-rich solution in the tower bottom is sent to the extraction treatment after being cooled by water; the intermediate component methanol is obtained in the side offtake section.
In a second aspect, embodiments of the present invention provide a separation apparatus for methyl acrylate crude product gas, comprising:
the light component removing tower system is used for removing light components from the crude product gas of methyl acrylate and recycling light components as raw materials;
the rectifying tower system is connected with the light component removing tower system and is used for carrying out azeotropic rectification treatment and extractive rectification treatment on the methyl acrylate crude product gas subjected to light component removing treatment; wherein azeotropic distillation is performed to remove formaldehyde and heavy ester components; the tower top compressed steam of azeotropic distillation treatment is used as a reboiler heat source of a light component removal tower system; extracting and rectifying formaldehyde solution obtained by azeotropic rectification by using water as an extractant to remove methanol components in the formaldehyde solution;
the extraction tower is connected with the rectifying tower system and is used for extracting formaldehyde solution obtained by extraction and rectification treatment, wherein a first extractant is adopted to extract the formaldehyde solution so as to remove heavy ester components in the formaldehyde solution, and a second extractant is adopted to remove formaldehyde from the oil phase;
the de-weight tower system is connected with the extraction tower and is used for de-weight treatment of the oil phase obtained by the extraction treatment, and light ester and water are recycled and respectively used as the first extractant and the second extractant of the extraction treatment; the heat source of the intermediate reboiler of the heavy-removal tower system adopts the gas phase at the top of the heavy-removal tower system as a heat source after being compressed and heated;
And the stripping tower system is connected with the extraction tower and is used for carrying out stripping treatment on the water phase obtained by the extraction treatment so as to recover light ester components and obtain a tower bottom dilute formaldehyde water solution.
In some embodiments, the light ends column system comprises:
the light component removing tower is used for removing light component from the crude product gas of methyl acrylate which is cooled to a preset temperature and enters the light component removing tower in a gas phase state; the tower bottom liquid of the light component removal tower enters the rectifying tower system for azeotropic rectification after being pumped and pressurized by a pump;
a light component removing tower reboiler connected with the light component removing tower and heating tower bottom liquid of the light component removing tower by taking the tower top compressed steam of azeotropic distillation treatment as a heat source;
a light component removal tower top air cooler connected with the tower top of the light component removal tower and used for cooling the tower top gas phase of the light component removal tower to a preset temperature;
a light component removal tower reflux tank connected with the light component removal tower top air cooler and used for accommodating the tower top gas phase of the light component removal tower cooled by the light component removal tower air cooler, wherein condensate in the light component removal tower reflux tank returns to the light component removal tower as reflux;
the light component removal tower top water cooler is connected with the light component removal tower reflux tank and is used for water-cooling the top gas phase component of the light component removal tower reflux tank to a preset temperature;
And the light component removing tower top tank is connected with the light component removing tower top water cooler and is used for accommodating the top gas phase component of the light component removing tower reflux tank after the light component removing tower top water cooler is cooled, and the condensate of the light component removing tower top tank is used as a recovered light component to return to the methyl acrylate reaction unit.
In some embodiments, the rectification column system comprises an azeotropic rectification column system for performing the azeotropic rectification process, the azeotropic rectification column system comprising:
the azeotropic distillation tower is connected with the light component removing tower system and is used for carrying out azeotropic distillation treatment on the methyl acrylate crude product gas after light component removal; the tower bottom of the azeotropic distillation tower is connected with the extraction distillation tower so that tower bottom liquid enters the extraction distillation tower after being pumped and pressed, and extraction distillation treatment is carried out;
the azeotropic distillation tower top gas compressor is connected with the tower top of the azeotropic distillation tower and is used for compressing and heating the tower top gas phase of the azeotropic distillation tower to be used as a reboiler heat source of the light component removal tower system;
the azeotropic distillation tower water cooler is connected with the light component removal tower reboiler and is used for cooling the gas phase at the top of the azeotropic distillation tower to a preset temperature after heat exchange of the reboiler of the light component removal tower system;
The azeotropic distillation tower reflux tank is connected with the azeotropic distillation tower water cooler and is used for accommodating the top gas of the azeotropic distillation tower after the azeotropic distillation tower water cooler is cooled; one part of condensate in the reflux tank of the azeotropic distillation tower is used as reflux to return to the azeotropic distillation tower, and the other part is sent to a downstream methyl acrylate hydrogenation unit;
and the azeotropic distillation tower reboiler is connected with the azeotropic distillation tower and is used for providing heat energy for the azeotropic distillation tower, and the azeotropic distillation tower reboiler is connected with a low-pressure steam pipeline.
In some embodiments, the rectification column system comprises an extractive rectification column system that employs water as an extractant to extractive rectify a formaldehyde solution resulting from azeotropic rectification, the extractive rectification column system comprising:
the extraction rectifying tower is connected with the tower kettle of the azeotropic rectifying tower and is used for carrying out extraction rectifying treatment on formaldehyde solution obtained by azeotropic rectifying treatment;
the extraction rectifying tower kettle liquid water cooler is connected with the tower kettle of the extraction rectifying tower, so that formaldehyde-rich solution at the tower kettle of the extraction rectifying tower is cooled by circulating water and then pumped and pressed to enter the extraction tower for extraction treatment;
The extraction rectifying tower condenser is connected with the top of the extraction rectifying tower and is used for cooling the gas phase at the top of the extraction rectifying tower to a preset temperature;
the extraction rectifying tower reflux tank is connected with the extraction rectifying tower condenser and is used for accommodating the top gas of the extraction rectifying tower after the extraction rectifying tower condenser is cooled, one part of condensate in the extraction rectifying tower reflux tank is used as reflux to return to the extraction rectifying tower, and the other part of condensate is used as a methanol solvent to return to the methyl acrylate reaction unit;
and the extraction rectifying tower reboiler is connected with the extraction rectifying tower and is used for providing heat energy for the extraction rectifying tower, and the extraction rectifying tower reboiler is connected with a low-pressure steam pipeline.
In some embodiments, the de-duplication column system comprises:
the heavy-removal tower is connected with the extraction tower and is used for carrying out heavy-removal treatment on the heavy-ester-rich oil phase obtained by the extraction treatment so as to remove heavy components in the oil phase and recover the extractant;
the heavy-removal tower top gas compressor is connected with the heavy-removal tower and is used for compressing and heating the tower top gas phase of the heavy-removal tower;
the middle boiler of the heavy removal tower is connected with the heavy removal tower top gas compressor so that the tower top gas phase of the heavy removal tower compressed and heated by the heavy removal tower top gas compressor enters the middle boiler of the heavy removal tower to be used as a heat source;
The de-weight tower top water cooler is connected with the de-weight tower middle boiler and is used for cooling the tower top gas phase of the de-weight tower after heat exchange by the de-weight tower middle boiler to a preset temperature;
the de-weight tower reflux tank is connected with the de-weight tower top water cooler and is used for accommodating the tower top gas phase of the de-weight tower after being cooled by the de-weight tower top water cooler, the cooled tower top gas phase of the de-weight tower is subjected to oil-water delamination in the de-weight tower reflux tank, part of the oil phase returns to the de-weight tower as reflux after being boosted, the other part returns to the bottom of the extraction tower as a first extractant, and the water phase returns to the top of the extraction tower as a second extractant after being boosted;
and the heavy-removal tower reboiler is connected with the heavy-removal tower and used for providing heat energy for the heavy-removal tower, and the heavy-removal tower reboiler is connected with a low-pressure steam pipeline.
In some embodiments, the stripper system comprises:
the stripping tower is connected with the extraction tower and is used for carrying out stripping treatment on the dilute formaldehyde solution obtained by the extraction treatment so as to remove light ester components in the formaldehyde aqueous solution; the tower bottom of the stripping tower is connected to a dilute formaldehyde recovery system through a pump;
a stripper condenser connected to the top of the stripper for water cooling the top gas phase of the stripper to a preset temperature;
A stripper overhead tank connected to the stripper condenser for containing a top gas phase of the stripper cooled by the stripper condenser, wherein a condensate in the stripper overhead tank is returned to the lower part of the extraction column after being boosted;
and the stripper reboiler is connected with the stripper and is used for providing heat energy for the stripper, and a low-pressure steam pipeline is connected to the stripper reboiler.
In some embodiments, the rectifying tower system comprises a baffle rectifying tower, wherein the baffle rectifying tower is used for carrying out azeotropic rectification treatment and extractive rectification treatment, a vertical baffle is arranged in the middle part of the baffle rectifying tower, the baffle divides the rectifying tower into an upper public rectifying section, a lower public stripping section, rectifying feeding sections and side line extraction sections which are positioned at two sides of the baffle, methyl acrylate crude product gas after the light removal treatment and water serving as an extractant enter from the rectifying feeding sections, and the rectifying feeding sections serve as a primary fractionating tower for prefractionation to finish the separation of light components and heavy components; the separation of light components and intermediate components is realized in the public rectifying section, and the gas phase at the top of the baffle rectifying tower enters the reboiler of the light component removal tower as a heat source after being compressed and heated; the separation of the middle component and the heavy component is realized in the public stripping section, and the tower bottom of the baffle rectifying tower is connected with an extraction rectifying tower bottom liquid water cooler so that the cooled formaldehyde-rich solution is subjected to extraction treatment in the extraction tower; the side-draw section is connected with the methyl acrylate reaction unit.
According to the separation method of the methyl acrylate crude product gas, impurities such as methyl acetate, formaldehyde, water, methanol, methacrolein, methyl methacrylate, acetic acid and heavy esters can be almost completely removed without losing MA, and trace MP enters a downstream MA hydrogenation MP unit along with MA products. In addition, the MA crude product gas (especially MA crude product gas prepared from coal-based methyl acetate and formaldehyde) separation method provided by the invention solves the technical problem of higher separation cost caused by lower MA concentration in MA crude product gas due to the adoption of a double-tower coupling heat pump formed by taking tower top compressed steam of extraction rectification, double-solvent extraction and azeotropic rectification as a reboiler heat source for light removal treatment, single-tower heat pump rectification formed by coupling tower top steam and an intermediate reboiler, and an advanced baffle rectification technology.
Drawings
In the drawings, which are not necessarily drawn to scale, like numerals may describe similar components in different views. The same reference numerals with letter suffixes or different letter suffixes may represent different instances of similar components. The accompanying drawings illustrate various embodiments by way of example in general and not by way of limitation, and together with the description and claims serve to explain the disclosed embodiments. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. Such embodiments are illustrative and not intended to be exhaustive or exclusive of the present apparatus or method.
FIG. 1 is a flow chart of a method for separating methyl acrylate crude product gas according to a first embodiment of the present invention;
FIG. 2 is a schematic structural view of a separation apparatus for methyl acrylate crude product gas according to the first embodiment of the present invention;
FIG. 3 is a schematic view showing the structure of a separation apparatus for crude methyl acrylate product gas according to a second embodiment of the present invention;
FIG. 4 is a table of key stream results for a 4.6 ten thousand ton MA/year methyl acrylate crude gas separation process provided in one embodiment of the invention.
In the figure: 1-a light ends column system; 2-an azeotropic distillation column system; 3-an extraction rectifying tower system; 4-an extraction tower; a 5-de-heavies column system; a 6-stripper system; 7-a baffle rectifying tower; 11-a light component removing tower; 12-a light ends column reboiler; 13-a light-removal tower top air cooler; 14-a reflux drum of the light component removal tower; 15-a light component removal tower top water cooler; 16-a light ends overhead tank; 21-an azeotropic distillation tower; 22-an azeotropic distillation column reboiler; 23-an azeotropic distillation overhead gas compressor; 24-an azeotropic rectifying tower water cooler; 25-a reflux tank of the azeotropic distillation tower; 31-an extraction rectifying tower; 32-extracting and rectifying tower reboiler; 33-an extraction rectification column condenser; 34-a reflux drum of the extraction rectifying tower; 35-an extraction rectifying tower kettle liquid water cooler; 51-a heavy-duty removal tower; 52-a heavy ends removal column reboiler; 53-a de-heavy overhead gas compressor; 54-a middle boiler of the heavy-removal tower; 55-a weight-removing tower top water cooler; 56-a heavy-duty removal tower reflux drum; 61-stripping column; 62-stripper reboiler; 63-stripper condenser; 64-stripper overhead tank; 71-a common rectifying section; 72-a public stripping section; 73-rectifying a feed section; 74-side offtake section; 75-separator rectifying column compressor; 76-a baffle rectifying tower top water cooler; 77-baffle rectifying tower reflux drum; 78-baffle rectifying tower reboiler; 79-baffle rectifying tower bottom liquid water cooler.
Detailed Description
The present invention will be described in detail below with reference to the drawings and detailed description to enable those skilled in the art to better understand the technical scheme of the present invention. Embodiments of the present invention will be described in further detail below with reference to the drawings and specific examples, but not by way of limitation.
The terms "first," "second," and the like, as used herein do not denote any order, quantity, or importance, but rather are used to distinguish one element from another. The word "comprising" or "comprises" and the like means that elements preceding the word encompass the elements recited after the word, and not exclude the possibility of also encompassing other elements. "upper", "lower", "left", "right", etc. are used merely to indicate relative positional relationships, which may also be changed when the absolute position of the object to be described is changed.
In the present invention, when it is described that a specific device is located between a first device and a second device, an intervening device may or may not be present between the specific device and the first device or the second device. When it is described that a particular device is connected to other devices, the particular device may be directly connected to the other devices without intervening devices, or may be directly connected to the other devices without intervening devices.
All terms (including technical or scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs, unless specifically defined otherwise. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
Techniques, methods, and apparatus known to one of ordinary skill in the relevant art may not be discussed in detail, but are intended to be part of the specification where appropriate.
FIG. 1 is a flow chart of a separation method for preparing methyl acrylate crude product gas from coal-based methyl acetate and formaldehyde according to one embodiment of the invention; FIG. 2 is a schematic structural view of a separation apparatus for methyl acrylate crude product gas according to the first embodiment of the present invention; fig. 3 is a schematic structural view of a separation apparatus for methyl acrylate crude product gas according to a second embodiment of the present invention. The apparatus shown in fig. 2 and 3 may implement the separation method of the embodiments of the present invention. Referring to fig. 1 to 3, a method for separating methyl acrylate crude product gas according to an embodiment of the present invention includes:
S1, carrying out light component removal treatment on methyl acrylate crude product gas, and recycling light components as raw materials;
s2, carrying out azeotropic distillation treatment on the methyl acrylate crude product gas after the light removal so as to remove formaldehyde and heavy ester components; wherein, the gas phase at the top of the azeotropic distillation treatment is compressed and heated and then used as a reboiler heat source for the light removal treatment;
s3, extracting and rectifying the formaldehyde solution obtained by azeotropic rectification by using water to remove methanol components in the formaldehyde solution;
s4, extracting the formaldehyde solution with methanol removed by extractive distillation, wherein a first extractant is adopted to extract the formaldehyde solution so as to remove organic components such as heavy esters and acetic acid in the formaldehyde solution, and a second extractant is adopted to extract the oil phase so as to remove formaldehyde;
s5, carrying out heavy removal treatment on the oil phase obtained by the extraction treatment, and recovering light ester and water to be respectively used as the first extractant and the second extractant of the extraction treatment; the intermediate reboiler for the de-duplication treatment adopts the gas phase at the top of the tower for the de-duplication treatment as a heat source after being compressed and heated;
s6, carrying out steam stripping treatment on the water phase obtained by the extraction treatment to recover the light ester component, and obtaining a tower bottom dilute formaldehyde aqueous solution.
According to the method for separating the methyl acrylate crude product gas, which is particularly prepared from coal-based methyl acetate and formaldehyde, provided by the embodiment of the invention, the technical problems of higher separation cost caused by lower MA concentration in MA crude product gas are solved because the double-tower coupling heat pump formed by taking the tower top compressed steam of extraction rectification, double-solvent extraction and azeotropic rectification as a reboiler heat source for light removal and the single-tower heat pump rectification formed by coupling the tower top steam with an intermediate reboiler are adopted. The separation method of methyl acrylate crude product gas provided by the invention can almost completely remove impurities such as methyl acetate, formaldehyde, water, methanol, methacrolein, methyl methacrylate, acetic acid, heavy ester and the like without losing methyl acrylate, and trace MP enters a downstream MA hydrogenation MP unit along with MA products.
In some embodiments, in step S1, the high-temperature methyl acrylate crude product gas from the MA reaction unit is heat-exchanged and cooled to a preset temperature, for example, 90-150 ℃, so that the crude product gas enters the light component removal tower 11 in a gas phase state for light component removal treatment, so as to reduce the steam consumption of the reboiler 12 of the light component removal tower connected to the tower kettle, and save energy consumption of the device. The operating pressure range of the light ends column 11 may be 0.05-0.40MPaG, which is suitable for the separation process of the light components of the crude product gas, and also avoids waste caused by excessive pressure rise.
In some embodiments, step S1 further comprises: the gas phase at the top of the light component removing tower 11 is cooled to a preset temperature by adopting a light component removing tower top air cooler 13, for example, 50-90 ℃, the condensate generated by cooling the gas phase at the top of the light component removing tower 11 returns to the light component removing tower 11 as reflux, the gas is cooled to the preset temperature by adopting a light component removing tower top water cooler 15, for example, 30-60 ℃, then enters a light component removing tower top tank 16, and the condensate at the bottom of the light component removing tower top tank 16 returns to the MA reaction unit as raw material for recycling methyl acetate. Because the tower top adopts a secondary condensation scheme, most of methyl acetate and methanol are condensed in the first stage, so most of heat load is concentrated, and the heat transfer final temperature of the first stage condensation is higher, so that a more energy-saving air cooling scheme can be adopted, the consumption of circulating water of a condenser of the light component removal tower 11 is greatly reduced, and the energy consumption of the whole device can be reduced.
In some embodiments, in step S1, the heat source of the light component removal tower reboiler 12 is vapor after the temperature is raised by vapor phase compression at the top of the tower for azeotropic distillation treatment, so as to form a double-tower coupling heat pump system, which can greatly save energy consumption; the bottom liquid of the light component removal tower 11 is pumped and pressurized and then is removed from the azeotropic distillation tower 21 to carry out azeotropic distillation treatment.
In some embodiments, in step S2, the MA crude product gas after the light component removal is subjected to azeotropic distillation to remove unreacted formaldehyde and heavy ester components in the product gas, and the MA and methanol mixture distilled from the top of the tower is sent to a downstream MA hydrogenation unit, and the tower bottom liquid is pumped and pressurized to the extractive distillation tower 31 for extractive distillation. Because MA and methanol mixture is distilled out from the tower top, the risk of polymerization of MA with high concentration is avoided, and methanol carried to the downstream along with MA can not influence the reaction of MA hydrogenation for MP preparation. This separation scheme avoids the use of energy intensive MA purification schemes due to the azeotrope formation of MA and methanol.
In some embodiments, in step S2, the vapor phase from the top of the azeotropic distillation process is compressed and warmed to serve as the heat source for the light ends column reboiler 12, thereby forming a double-column coupled heat pump distillation system. Therefore, the high-grade steam energy source used by the light component removal tower reboiler 12 is avoided, the circulating water consumption of the azeotropic distillation tower condenser is greatly reduced, and the energy-saving effect of the whole device is obvious only at the cost of consuming a small amount of compression work.
The azeotropic distillation column reboiler 22 may employ low pressure steam as a heat source; the bottom liquid of the azeotropic distillation tower 21 is pumped and pressurized and then is removed for extraction and distillation treatment.
In some embodiments, in step S3, the formaldehyde solution after MA removal is subjected to extractive distillation to remove the methanol component of the formaldehyde solution. The methanol gas phase of the azeotropic distillation section is washed by adopting water as an extractant so as to avoid formaldehyde component carried by the methanol fraction at the top of the tower. The dosage (mass) of the extractant water is 0.3-10 times of the feeding quantity (mass). The extractive distillation column 31 can be operated at normal pressure, the top steam of the extractive distillation column 31 can be cooled by an air cooler, one part of the condensate obtained by cooling is used as reflux return column, and the other part is used as recovered methanol solvent to return to the MA reaction unit. The heat source of the extraction rectifying tower reboiler 32 can adopt low-pressure steam, the tower bottom liquid of the extraction rectifying tower 31 is cooled to 30-50 ℃ by circulating water, and then is pumped and pressurized to the extraction tower 4.
In some embodiments, in step S4, the formaldehyde-rich solution in the bottom of the extractive distillation column 31 is subjected to an extraction treatment with an ester (first extractant) in order to remove the heavy esters, acetic acid, and other organic components from the formaldehyde solution. The first extractant is light methyl propionate, methyl acrylate and methyl isobutyrate, for example, methyl propionate can be selected as the first extractant. The amount (mass) of the first extractant ester is 0.2 to 8 times the feed amount (mass). The overhead oil phase is subjected to a de-methanization treatment with water (second extractant) to avoid the formaldehyde component from being carried into the downstream de-duplication treatment (de-duplication column 51). The amount (mass) of the second extractant water is 0.1-6 times of the feeding amount (mass). The light components from the stripper 61 are returned to the lower part of the extraction column 4 for re-separation to reduce the loss of the first extractant (ester). A small amount of water from the de-weight column 51 is returned to the extraction column 4 as the second extractant. The extraction tower 4 can be a rotary disk tower, the operation temperature of the extraction tower 4 can be 30-50 ℃, and the operation pressure can be 0.30-0.90MPaG.
In some embodiments, in step S5, the oil phase from the top of the extraction column 4 is subjected to a de-weight treatment by the de-weight column 51, and the de-weight column 51 has the recovery function of the extractant at the same time. The de-weight tower 51 can be operated under normal pressure, and the de-weight tower 51 is provided with a middle boiler for further energy saving, and the tower top steam of the de-weight tower 51 is compressed and then used as a heat source of the middle boiler 54 of the de-weight tower, so that the steam consumption of the reboiler 52 of the de-weight tower is greatly reduced, and the circulating water consumption of the condenser of the de-weight tower 51 is also reduced. The top gas of the de-weight tower 51 subjected to heat exchange by the middle boiler 54 of the de-weight tower is cooled to a preset temperature, for example, 30-50 ℃, enters the reflux tank 56 of the de-weight tower, the condensate is subjected to oil-water phase separation operation in the reflux tank 56 of the de-weight tower, part of the boosted oil phase is taken as reflux to return to the tower, the other part is taken as the first extractant (ester) to return to the bottom of the extraction tower 4, and the boosted water phase is taken as the second extractant (water) to return to the top of the extraction tower 4. The heat source of the heavy-removal tower reboiler 52 can adopt low-pressure steam, and the heavy components in the tower bottom of the heavy-removal tower 51 can be further recycled after being taken as byproducts and pumped.
In some embodiments, in step S6, the dilute formaldehyde solution from the bottom of the extraction tower 4 is subjected to a stripping treatment by a stripping tower 61 to remove light ester components in the formaldehyde aqueous solution; the stripping column 61 may be operated at normal pressure, and the overhead vapor of the stripping column 61 is cooled to a predetermined temperature by circulating water, for example, the predetermined temperature may be in the range of 30 to 50 ℃, and the condensate obtained by cooling is returned to the lower portion of the extraction column 4 after being boosted for ester recovery. The tower bottom liquid of the stripping tower 61 is pumped and pressurized to remove the dilute formaldehyde recovery system.
As shown in fig. 2 to 3, the embodiment of the present invention also provides a separation apparatus for methyl acrylate crude product gas, which can realize the separation method of the above embodiment, and the following embodiments of the separation apparatus can be used to understand the embodiments of the separation method, and the embodiments of the separation method can also be used to explain the embodiments of the separation apparatus.
Referring to fig. 2 and 3, the separation device for methyl acrylate crude product gas provided by the embodiment of the invention comprises:
a light component removal column system 1 for removing light components from the crude methyl acrylate product gas and recovering the light components as raw materials;
the rectifying tower system is connected with the light component removing tower system 1 and is used for carrying out azeotropic rectification treatment and extractive rectification treatment on the methyl acrylate crude product gas subjected to light component removing treatment; wherein, the azeotropic distillation treatment is carried out to remove formaldehyde, heavy esters and other heavy components; the tower top compressed steam of azeotropic distillation treatment is used as a reboiler heat source of the light component removal tower system 1; extracting and rectifying formaldehyde solution obtained by azeotropic rectification by using water as an extractant to remove methanol components in the formaldehyde solution;
The extraction tower 4 is connected with the rectifying tower system and is used for extracting the formaldehyde solution obtained by extraction and rectification treatment, wherein a first extractant is adopted to extract the formaldehyde solution so as to remove heavy esters, acetic acid and other organic components in the formaldehyde solution, and a second extractant is adopted to remove formaldehyde from the oil phase;
a de-weight column system 5 connected with the extraction column 4 for de-weight treatment of the oil phase obtained by the extraction treatment, and recovering light ester and water as a first extractant and a second extractant of the extraction treatment respectively; the heat source of the intermediate reboiler of the weight removing tower system 5 adopts the gas phase at the top of the weight removing tower system 5 as a heat source after being compressed and heated;
and a stripping tower system 6 connected with the extraction tower 4 and used for carrying out stripping treatment on the water phase obtained by the extraction treatment so as to recover light ester components and obtain a tower bottom dilute formaldehyde water solution.
According to the separation equipment for the methyl acrylate crude product gas prepared from the coal-based methyl acetate and the formaldehyde, disclosed by the invention, the technical problems of higher separation cost caused by lower MA concentration in MA crude product gas are solved because the double-tower coupling heat pump formed by taking the extractive distillation, the double-solvent extraction tower 4 and the tower top compressed steam subjected to azeotropic distillation as the reboiler heat source of the light component removal tower system 1 and the heavy component removal tower system 5 formed by coupling the tower top steam and the intermediate reboiler are adopted. The separation equipment of the methyl acrylate crude product gas provided by the invention can almost completely remove impurities such as methyl acetate, formaldehyde, water, methanol, methacrolein, methyl methacrylate, acetic acid, heavy ester and the like without losing methyl acrylate, and trace MP enters a downstream MA hydrogenation MP unit along with MA products.
In some embodiments, referring to fig. 1 and 2, the light ends column system 1 comprises a light ends column 11, a light ends column reboiler 12, a light ends overhead air cooler 13, a light ends column reflux drum 14, a light ends overhead water cooler 15, and a light ends overhead drum 16.
The light component removing tower 11 is used for removing light component from the crude product gas of methyl acrylate which is cooled to a preset temperature and enters the light component removing tower 11 in a gas phase state, and tower bottom liquid of the light component removing tower 11 enters a rectifying tower system for azeotropic rectifying after being pumped and pressurized. The preset temperature can be, for example, 90-150 ℃, so that the product gas enters the light component removal tower 11 in a gas phase state for light component removal treatment, the steam consumption of the reboiler 12 of the light component removal tower is reduced, and the energy consumption of the device is saved. The operating pressure range of the light ends column 11 may be 0.05-0.40MPaG, which is suitable for the separation process of the light components of the crude product gas, and can avoid waste caused by excessive pressure rise.
And a light component removing tower reboiler 12 connected to the light component removing tower 11 and heating the tower bottom liquid of the light component removing tower 11 by using the tower top compressed steam of azeotropic distillation treatment as a heat source. The heat source of the light component removal tower reboiler 12 is the tower top steam subjected to azeotropic distillation treatment after compression and temperature rise, and the two towers form a double-tower coupling heat pump system, so that the energy consumption of the whole device can be greatly saved; the kettle liquid of the light component removal tower 11 is subjected to azeotropic distillation treatment after being pumped and pressurized.
A light component removal tower top air cooler 13 connected to the tower top of the light component removal tower 11 for cooling the tower top gas phase of the light component removal tower 11 to a preset temperature; for example 50-90 deg.c.
A light component removal column reflux drum 14 connected to the light component removal column top air cooler 13 for accommodating the top gas phase of the light component removal column 11 cooled by the light component removal column top air cooler 13, and returning the condensate in the light component removal column reflux drum 14 to the light component removal column 11 as reflux.
A light component removal tower top water cooler 15 connected with the light component removal tower reflux drum 14 for water-cooling the top gas phase component of the light component removal tower reflux drum 14 to a preset temperature; for example 30-60 deg.c.
A light component removal tower top tank 16 connected to the light component removal tower top water cooler 15 for containing the top gas phase component of the light component removal tower reflux tank 14 after cooling by the light component removal tower top water cooler 15, and the condensate in the light component removal tower top tank 16 is returned to the MA reaction unit as a recovered light component; because the tower top adopts a secondary condensation scheme, most of methyl acetate and methanol are condensed in the first stage, most of heat load is concentrated, and the heat transfer final temperature of the first stage condensation is higher, so that a more energy-saving air cooling scheme can be adopted, the circulating water consumption of the condenser of the light component removal tower 11 is greatly reduced, and the energy consumption of the whole device can be reduced.
In some embodiments, referring to fig. 2, the rectification column system comprises an azeotropic rectification column system 2 for performing azeotropic rectification treatment, the azeotropic rectification column system 2 comprising an azeotropic rectification column 21, an azeotropic rectification column reboiler 22, an azeotropic rectification column top gas compressor 23, an azeotropic rectification column water cooler 24, and an azeotropic rectification column reflux drum 25.
An azeotropic distillation column 21 connected to the light component removal column 11 of the light component removal column system 1, for performing azeotropic distillation on the methyl acrylate crude product gas after light component removal; the tower bottom of the azeotropic distillation tower 21 is connected with the extraction distillation tower 31 of the subsequent extraction distillation tower system 3, so that the tower bottom liquid enters the extraction distillation tower 31 after being pumped and pressurized, and extraction distillation treatment is carried out;
an azeotropic distillation column top gas compressor 23 connected to the top of the azeotropic distillation column 21 for compressing and heating the top gas phase of the azeotropic distillation column 21 to serve as a reboiler heat source for the light component removal column 11 of the light component removal column system 1. Thereby forming a double-tower coupling heat pump rectification system. In this way, the use of high-grade steam energy source by the light component removal tower reboiler 12 is avoided, the circulating water consumption of the condenser (water cooler) of the azeotropic distillation tower 21 is greatly reduced, and only a small amount of compression work is consumed, so that the energy-saving effect of the whole device is obvious.
And an azeotropic distillation column water cooler 24 connected to the light component removal column reboiler 12 for cooling the top gas of the azeotropic distillation column 21 subjected to heat exchange by the reboiler of the light component removal column system 1 to a predetermined temperature.
An azeotropic distillation column reflux drum 25 connected to the azeotropic distillation column water cooler 24 for accommodating the overhead gas of the azeotropic distillation column 21 after cooling by the azeotropic distillation column water cooler 24; part of the condensate in the reflux drum 25 of the azeotropic distillation column returns to the azeotropic distillation column 21 as reflux, and the other part is sent to the downstream MA hydrogenation unit.
And the azeotropic distillation tower reboiler 22 is connected with the azeotropic distillation tower 21 and is used for providing heat energy for the azeotropic distillation tower 21, and the azeotropic distillation tower reboiler 22 is connected with a low-pressure steam pipeline so as to adopt low-pressure steam as a heat source thereof.
In some embodiments, referring to fig. 2, the rectifying tower system includes an extractive rectifying tower system 3, the extractive rectifying tower system 3 uses water as an extractant to perform extractive rectifying treatment on formaldehyde solution obtained by azeotropic rectifying treatment, and the extractive rectifying tower system 3 includes an extractive rectifying tower 31, an extractive rectifying tower reboiler 32, an extractive rectifying tower condenser 33, an extractive rectifying tower reflux tank 34 and an extractive rectifying tower bottom liquid water cooler 35;
an extractive distillation column 31 connected to the bottom of the azeotropic distillation column 21 for extractive distillation of the formaldehyde solution (bottom liquid of the azeotropic distillation column 21) obtained by azeotropic distillation; the tower bottom of the extraction rectifying tower 31 is connected with the extraction tower 4, so that formaldehyde-rich solution in the tower bottom of the extraction rectifying tower 31 is cooled by an extraction rectifying tower bottom liquid water cooler 35 and then enters the extraction tower 4 for extraction treatment after being pumped and pressurized;
An extractive distillation column condenser 33 connected to the top of the extractive distillation column 31 for cooling the top gas of the extractive distillation column 31 to a preset temperature; the extraction rectifying column condenser 33 may employ an air cooler.
An extraction rectifying tower reflux tank 34 connected with the extraction rectifying tower condenser 33 for accommodating the top gas of the extraction rectifying tower 31 after the extraction rectifying tower condenser 33 is cooled, wherein a part of the condensate in the extraction rectifying tower reflux tank 34 is used as reflux to return to the extraction rectifying tower 31, and the other part is used as methanol solvent to return to the methyl acrylate reaction unit;
and the extraction rectifying tower reboiler 32 is connected with the extraction rectifying tower 31 and is used for providing heat energy for the extraction rectifying tower 31, and the extraction rectifying tower reboiler 32 is connected with a low-pressure steam pipeline so as to adopt low-pressure steam as a heat source thereof.
In some embodiments, referring to fig. 2 and 3, the de-heavies column system 5 includes a de-heavies column 51, a de-heavies column reboiler 52, a de-heavies column overhead gas compressor 53, a de-heavies column mid-boiler 54, a de-heavies column overhead water cooler 55, and a de-heavies column reflux drum 56.
A heavy-removal column 51 connected to the extraction column 4 for subjecting the heavy-ester-rich oil phase (the overhead oil phase of the extraction column 4) obtained by the extraction treatment to heavy-removal treatment to remove heavy components in the oil phase and recovering the extractant;
A de-weight tower top gas compressor 53 connected to the de-weight tower 51 for compressing and heating the tower top gas phase of the de-weight tower 51;
and a heavy-duty middle boiler 54 connected to the heavy-duty top gas compressor 53 so that the top gas phase of the heavy-duty column 51 compressed and warmed by the heavy-duty top gas compressor 53 enters the heavy-duty middle boiler 54 as a heat source. The vapor at the top of the de-weight tower 51 is compressed and then used as a heat source of the middle boiler 54 of the de-weight tower, so that the vapor consumption of the reboiler 52 of the de-weight tower is greatly reduced, and the circulating water consumption of the condenser of the de-weight tower 51 is also reduced.
A de-weight tower top water cooler 55 connected to the de-weight tower middle boiler 54 for cooling the tower top gas phase of the de-weight tower 51 after heat exchange by the de-weight tower middle boiler 54 to a preset temperature; for example 30-50 deg.c.
The de-weight tower reflux tank 56 is connected with the de-weight tower top water cooler 55 and is used for accommodating the tower top gas phase of the de-weight tower 51 after being cooled by the tower top water cooler of the de-weight tower 51, the cooled tower top gas of the de-weight tower 51 is subjected to oil-water delamination in the de-weight tower reflux tank 56, part of the oil phase is returned to the de-weight tower 51 as reflux after being boosted, the other part is returned to the bottom of the extraction tower 4 as the first extractant, and the water phase is returned to the top of the extraction tower 4 as the second extractant after being boosted.
A heavy-removal tower reboiler 52 connected to the heavy-removal tower 51 for providing heat energy to the heavy-removal tower 51, wherein the heavy-removal tower reboiler 52 is connected with a low-pressure steam pipeline for using low-pressure steam as a heat source thereof;
the heavy components in the tower bottom of the heavy removal tower 51 are connected with a recovery processing system so as to recover the heavy components in the tower bottom.
In some embodiments, referring to fig. 2 and 3, stripper system 6 includes a stripper 61, a stripper reboiler 62, a stripper condenser 63, and a stripper overhead tank 64.
A stripping column 61 connected to the extraction column 4 for stripping the diluted formaldehyde solution (bottom liquid of the extraction column 4) obtained by the extraction treatment to remove light ester components in the formaldehyde aqueous solution; the tower bottom of the stripping tower 61 is connected to a dilute formaldehyde recovery system through a pump;
a stripper condenser 63 connected to the top of the stripper 61 for water cooling the top gas phase of the stripper 61 to a preset temperature. Stripper condenser 63 may be a water chiller.
A stripper column overhead tank 64 connected to the stripper column condenser 63 for containing the overhead gas of the stripper column 61 cooled by the stripper column condenser 63, and the condensate in the stripper column overhead tank 64 is returned to the extraction column 4 after being boosted;
a stripper reboiler 62 connected to the stripper 61 for providing heat energy to the stripper 61, and a low pressure steam line connected to the stripper reboiler 62 for using low pressure steam as its heat source.
In some embodiments, referring to fig. 3, the rectifying tower system includes a baffle rectifying tower 7 for performing azeotropic rectification and extractive rectification, a vertical baffle is disposed in the middle of the baffle rectifying tower 7, the baffle divides the rectifying tower into an upper common rectifying section 71, a lower common stripping section 72, and rectifying feeding sections 73 and side extraction sections 74 located at two sides of the baffle, the methyl acrylate crude product gas after the light component removal and water serving as an extractant enter from the rectifying feeding sections 73, and the rectifying feeding sections 73 play a role of a primary fractionating tower to separate light components and heavy components; the separation of light components and intermediate components is realized in the common rectifying section 71, and the tower top gas of the baffle rectifying tower 7 is compressed and heated by the baffle rectifying tower compressor 75 and then is used as a heat source of the light component removing tower reboiler 12 of the light component removing tower system 1; a separator rectifying tower water cooler 76 connected to the light component removal tower reboiler 12 for cooling the top gas of the separator rectifying tower subjected to heat exchange by the reboiler of the light component removal tower system 1 to a preset temperature; a baffle rectifying tower reflux tank 77 connected to the baffle rectifying tower water cooler 76, wherein a part of the condensate in the baffle rectifying tower reflux tank 77 is returned to the common rectifying section 71 as reflux, and the other part is sent to the downstream MA hydrogenation unit; the separation of intermediate components and heavy components is realized in the public stripping section 72, and the formaldehyde-rich solution in the tower bottom is sent to extraction treatment; an intermediate methanol component is obtained in side offtake section 74. The separator rectifying column reboiler 78 is connected to a low pressure steam line to use low pressure steam as its heat source. The formaldehyde-rich solution in the tower bottom of the baffle rectifying tower 7 is cooled by a baffle rectifying tower bottom liquid water cooler 79 and then sent to extraction treatment. . In this embodiment, the azeotropic distillation column 21 and the extractive distillation column 31 in the embodiment shown in fig. 2 are coupled as a baffle distillation column 7 in the embodiment shown in fig. 3; the baffle rectifying tower is a special structure of a complete thermal coupling tower, and the ingenious use of the baffle realizes the functions of the two towers; compared with the traditional two-tower process, the method effectively avoids the remixing phenomenon in the two-tower process, is more effective in the thermodynamics of the towers, can obviously reduce the load of a condenser and the load of a reboiler, and can save the equipment investment and the occupied area of the device.
The following describes the use of the apparatus for separating methyl acrylate crude product gas, which is prepared from methyl acetate and formaldehyde.
The crude product gas of methyl acrylate containing 3.91% nitrogen, 39.27% methyl acetate, 6.91% formaldehyde, 40.77% methanol, 0.04% methacrolein, 6.74% methyl acrylate, 0.07% methyl propionate, 0.08% methyl methacrylate, 1.66% water, 0.24% acetic acid, and 0.32% by weight was used as the experimental object, and the scale was 4.6 ten thousand tons/year of methyl acrylate, see fig. 2, and the steps were as follows:
(1) The product gas is light: the high-temperature methyl acrylate crude product gas from the MA reaction unit is subjected to heat exchange to 90-150 ℃ so that the product gas enters the light component removal tower 11 in a gas phase state, and the operating pressure of the light component removal tower 11 is 0.05-0.40MPaG. The gas phase at the top of the light component removing tower 11 is cooled to 50-90 ℃ by a light component removing tower top air cooler 13, then enters a light component removing tower reflux tank 14, condensate returns to the light component removing tower 11 as reflux, gas is cooled to 30-60 ℃ by a light component removing tower top water cooler 15 and enters a light component removing tower top tank 16, and the condensate at the bottom of the light component removing tower top tank 16 returns to the MA reaction unit as raw material of recovered methyl acetate. Because the tower top adopts a secondary condensation scheme of air cooling and water cooling, the circulating water consumption of the condenser of the light component removal tower 11 is greatly reduced, and the energy consumption of the whole device is further reduced. The heat source of the light component removal tower reboiler 12 is the vapor after the temperature rise of the tower top compression of the azeotropic distillation tower 21, and the two towers form a double-tower coupling heat pump system, so that the energy consumption of the whole device can be greatly saved; the tower bottom liquid of the light component removing tower 11 is pumped and pressurized to remove the azeotropic rectifying tower 21.
(2) And (3) rectifying product gas: and (3) carrying out azeotropic distillation treatment on the MA crude product gas subjected to the light removal in the step (1) through an azeotropic distillation tower 21 to remove unreacted formaldehyde, heavy esters and other heavy components in the product gas, wherein the azeotropic distillation tower 21 is operated at normal pressure so as to avoid corrosion of equipment caused by excessive high temperature of a pressurized operation tower kettle. The gas phase at the top of the azeotropic distillation column 21 is pressurized to 0.15-0.60MPaG by an azeotropic distillation column top gas compressor 23, the temperature is correspondingly increased to 95-150 ℃, the gas at the top of the azeotropic distillation column 21 after the temperature is increased is used as a heat source of a light component removal column reboiler 12, thereby forming a double-column coupling heat pump distillation system, the gas at the top of the azeotropic distillation column 21 is cooled to 60-90 ℃ by an azeotropic distillation column water cooler 24, the condensate enters an azeotropic distillation column reflux tank 25, one part is used as reflux, and the other part is used as MA and methanol mixture to a MA hydrogenation unit at the downstream. The heat source of the azeotropic distillation column reboiler 22 is low pressure steam. The tower bottom liquid is pumped and pressurized to be removed from the extraction rectifying tower 31. The double-tower coupling heat pump rectification system is formed by the light component removing tower 11 and the azeotropic rectification tower 21. Therefore, the high-grade steam energy source used by the light component removal tower reboiler 12 is avoided, the circulating water consumption of the condenser of the azeotropic distillation tower 21 is greatly reduced, and only a small amount of compression work is consumed, so that the energy-saving effect of the whole device is obvious.
(3) Removing methanol from concentrated aldehyde: and (3) extracting and rectifying the concentrated formaldehyde solution at the tower bottom of the azeotropic rectifying tower 21 in the step (2), wherein the extracting and rectifying tower 31 is preferably operated at normal pressure, methanol components are distilled out from the tower top, and an extracting agent (water) is adopted to wash the methanol gas phase of the rectifying section so as to prevent formaldehyde from being entrained in the methanol fraction at the tower top. The overhead vapor is cooled to 50-80 ℃ by an extraction rectifying tower condenser 33, and part of the condensate is returned to the tower as reflux, and the other part is returned to the MA reaction unit as recovered methanol. The extraction rectifying tower condenser 33 is preferably an air cooler so as to reduce the circulating water consumption of the device and save energy consumption. The heat source of the extraction rectifying tower reboiler 32 is low-pressure steam, the tower bottom liquid of the extraction rectifying tower 31 is cooled to 30-50 ℃ by circulating water through an extraction rectifying tower bottom liquid water cooler 35, and then is pumped and pressurized to the extraction tower 4.
(4) De-duplication of formaldehyde solution: the formaldehyde-rich solution at the bottom of the extractive distillation column 31 in step (3) is subjected to extraction treatment with an ester (first extractant) by an extraction column 4 in order to remove heavy esters and acetic acid components from the formaldehyde solution. The oil phase at the top of the extraction column 4 is subjected to a formaldehyde removal treatment with water (second extractant) to avoid the formaldehyde component from being carried into the downstream weight removal column 51. The light ester component from the stripper 61 is returned to the lower portion of the extraction column 4 for re-separation to reduce the loss of the first extractant (ester). The light ester recovered from the de-weight column 51 is returned to the bottom of the extraction column 4 as a first extractant, and a small amount of water from the de-weight column reflux drum 56 is returned to the top of the extraction column 4 as a second extractant (water). The extraction column 4 may be in the form of a rotary tray column, operating at a temperature of 30-50℃and operating at a pressure of 0.30-0.90MPaG.
(5) Removing heavy weight and recovering extractant: the ester-rich oil phase from the top of the extraction column 4 of step (4) enters a deentrainment column 51 to remove heavy components in the oil phase. The operation pressure of the de-weight tower 51 is 0.05-0.30MPaG, and for further energy saving, the de-weight tower 51 is provided with a de-weight tower middle boiler 54, and the tower top gas of the de-weight tower 51 is compressed by a de-weight tower top gas compressor 53 and then used as a heat source of the de-weight tower middle boiler 54, so that the steam consumption of the de-weight tower reboiler 52 is greatly reduced. The top gas of the de-weight tower 51 subjected to heat exchange by the middle boiler 54 of the de-weight tower is cooled to 30-50 ℃ by the water cooler 55 at the top of the de-weight tower, then enters the reflux tank 56 of the de-weight tower, condensate is subjected to oil-water phase separation operation in the reflux tank 56 of the de-weight tower, part of the boosted oil phase is returned to the de-weight tower 51 as reflux, the other part is returned to the bottom of the extraction tower 4 as a first extractant (ester), and the boosted water phase is returned to the top of the extraction tower 4 as a second extractant (water). The heat source of the heavy-removal tower reboiler 52 is low-pressure steam, and the heavy components in the tower bottom of the heavy-removal tower 51 can be further recycled after being taken as byproducts and pumped.
(6) Dilute aldehyde stripping: the dilute formaldehyde solution from the bottom of the extraction column 4 of the step (4) enters a stripping column 61 to remove light ester components in the formaldehyde aqueous solution. The stripper 61 is operated at a pressure of 0.05-0.30MPaG. The top gas of the stripping tower 61 is cooled to 30-50 ℃ through a stripping tower condenser 63, condensate enters a stripping tower top tank 64, and after being boosted by a pump, the condensate returns to the lower part of the extraction tower 4 for ester recovery. The heat source of the stripper reboiler 62 is low-pressure steam, and the tower bottom liquid of the stripper 61 is pumped and pressurized to dilute formaldehyde recovery system.
Alternatively, referring to fig. 3, the azeotropic distillation column 21 in step S2 and the extractive distillation column 31 in step S3 may be coupled as one distillation column using a partition, i.e., the partition distillation column 7. The structure of the baffle rectifying tower 7 is that a vertical baffle is arranged in a rectifying tower, and the rectifying tower is divided into four parts of an upper public rectifying section 71 (corresponding to an azeotropic rectifying tower 21), a lower public stripping section 72 (corresponding to an extraction rectifying tower 31), and rectifying feeding sections 73 and side line extraction sections 74 at two sides of the baffle. The rectification feeding section 73 plays a role of a primary fractionating tower and finishes the separation of light components and heavy components; separation of the light and intermediate components is achieved in a common rectifying section 71 and a liquid phase reflux is provided; separation of the intermediate and heavy components is effected in a common stripping section 72 and vapor phase reflux is provided; high purity intermediate components are obtained in side draw section 74. The baffle rectifying tower 7 is a special structure of a complete thermal coupling tower, and the ingenious use of the baffle realizes the functions of two towers. The azeotropic rectifying tower 21 and the extractive rectifying tower 31 are coupled into one rectifying tower, compared with the traditional two-tower process, the remixing phenomenon in the two-tower process is effectively avoided, the thermodynamics of the tower is more effective, the condenser load and the reboiler load of the baffle rectifying tower 7 can be obviously reduced, and the equipment investment and the occupied area of the device can be saved. The baffle rectifying tower 7 can also solve the problem that the energy consumption of the extractive rectifying tower 31 is increased when the amount of methanol distilled from the top of the extractive rectifying tower 31 is large. The baffle rectifying tower 7 can reduce the energy consumption of the whole device.
The results of the first example key stream experiments are shown in table in fig. 4.
Furthermore, although exemplary embodiments have been described herein, the scope thereof includes any and all embodiments having equivalent elements, modifications, omissions, combinations (e.g., of the various embodiments across), adaptations or alterations as pertains to the present application. The elements in the claims are to be construed broadly based on the language employed in the claims and are not limited to examples described in the present specification or during the practice of the application, which examples are to be construed as non-exclusive. It is intended, therefore, that the specification and examples be considered as exemplary only, with a true scope and spirit being indicated by the following claims and their full scope of equivalents.
The above description is intended to be illustrative and not restrictive. For example, the above-described examples (or one or more aspects thereof) may be used in combination with each other. For example, other embodiments may be used by those of ordinary skill in the art upon reading the above description. In addition, in the above detailed description, various features may be grouped together to streamline the application. This is not to be interpreted as an intention that the disclosed features not being claimed are essential to any claim. Rather, inventive subject matter may lie in less than all features of a particular disclosed embodiment. Thus, the following claims are hereby incorporated into the detailed description as examples or embodiments, with each claim standing on its own as a separate embodiment, and it is contemplated that these embodiments may be combined with one another in various combinations or permutations. The scope of the application should be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.
The above embodiments are only exemplary embodiments of the present invention and are not intended to limit the present invention, the scope of which is defined by the claims. Various modifications and equivalent arrangements of this invention will occur to those skilled in the art, and are intended to be within the spirit and scope of the invention.
Claims (7)
1. A process for separating methyl acrylate crude product gas comprising:
the methyl acrylate crude product gas is subjected to light removal treatment, and light components are recovered as raw materials;
carrying out azeotropic distillation treatment on the methyl acrylate crude product gas after the light removal to remove formaldehyde and heavy ester components; wherein, the gas phase at the top of the azeotropic distillation treatment is compressed and heated and then used as a reboiler heat source for the light removal treatment;
extracting and rectifying the formaldehyde solution obtained by azeotropic rectification by water to remove methanol components in the formaldehyde solution;
extracting formaldehyde solution from which methanol is removed by extractive distillation, wherein a first extractant is adopted to extract the formaldehyde solution so as to remove heavy ester components in the formaldehyde solution, and a second extractant is adopted to extract an oil phase so as to remove formaldehyde; the first extractant is methyl propionate or methyl acrylate or methyl isobutyrate; the second extractant is water;
Carrying out de-weight treatment on the oil phase obtained by the extraction treatment, and recovering light ester and water to be respectively used as the first extractant and the second extractant of the extraction treatment; the intermediate reboiler for the de-duplication treatment adopts the gas phase at the top of the tower for the de-duplication treatment as a heat source after being compressed and heated;
and (3) carrying out steam stripping treatment on the water phase obtained by the extraction treatment to recover the light ester component, thereby obtaining a tower bottom dilute formaldehyde water solution.
2. The process of claim 1, wherein the subjecting the crude methyl acrylate product gas to a light ends treatment comprises:
cooling the crude product gas of methyl acrylate to a preset temperature, and enabling the crude product gas of methyl acrylate to enter a light component removing tower in a gas phase state for light component removing treatment;
cooling the top gas phase of the light component removal tower to a preset temperature by adopting an air cooler, entering a light component removal tower reflux tank, returning condensate in the light component removal tower reflux tank as reflux to the light component removal tower, and enabling the top gas phase component of the light component removal tower reflux tank to enter a light component removal tower top tank, wherein the condensate in the light component removal tower top tank is returned to the methyl acrylate reaction unit as a recovered light component;
the bottom liquid of the light component removal tower is subjected to azeotropic distillation after being pumped and pressurized.
3. The method according to claim 1, wherein the azeotropic distillation of the methyl acrylate crude gas after the light component removal comprises:
After the methyl acrylate crude product gas is subjected to light removal treatment, the crude product gas is sent to an azeotropic distillation tower for azeotropic distillation through pressure extraction;
after heat exchange of the tower top gas phase subjected to azeotropic distillation treatment by the reboiler subjected to light removal treatment, water cooling is carried out to reach a preset temperature, and the gas phase enters a reflux tank of the azeotropic distillation tower, wherein part of condensate in the reflux tank of the azeotropic distillation tower is returned to the azeotropic distillation tower as reflux, and the other part of condensate is sent to a downstream methyl acrylate hydrogenation unit;
the reboiler of the azeotropic distillation tower can adopt low-pressure steam as a heat source;
and extracting and rectifying tower bottom liquid of the azeotropic rectifying tower after pumping and pressurizing.
4. The method according to claim 1, wherein the extractive distillation of the formaldehyde solution obtained by azeotropic distillation with water comprises:
the formaldehyde solution obtained by azeotropic distillation is sent to an extraction distillation tower for extraction distillation treatment after being pressurized;
cooling the gas phase at the top of the extractive distillation column to a preset temperature by adopting an air cooler, wherein one part of the obtained condensate is used as reflux, and the other part of the condensate is used as a methanol solvent to return to the methyl acrylate reaction unit;
the reboiler of the extraction rectifying tower adopts low-pressure steam as a heat source;
And cooling the formaldehyde-rich solution at the tower bottom of the extraction rectifying tower by circulating water, and extracting by a pump.
5. The method of claim 1, wherein the oil phase obtained by the extraction treatment is subjected to a de-duplication treatment, comprising:
the heavy ester-rich oil phase obtained from the extraction treatment enters a heavy-removal tower to remove heavy components in the oil phase, and an extracting agent is recovered;
after the temperature of the gas phase at the top of the heavy removal tower is increased by compression, the gas phase is used as a heat source of a boiling device in the heavy removal tower, the gas phase at the top of the heavy removal tower after heat exchange by the boiling device in the heavy removal tower is cooled to a preset temperature by water and then enters a reflux tank of the heavy removal tower for layering, part of the boosted oil phase is used as reflux and returns to the heavy removal tower, the other part of the boosted oil phase is used as a first extractant and returns to the lower part of the extraction tower, and the boosted water phase is used as a second extractant and returns to the upper part of the extraction tower;
the heavy-removal tower reboiler of the heavy-removal tower adopts low-pressure steam as a heat source;
and (3) recycling the heavy components in the tower bottom of the heavy removal tower.
6. The process according to claim 1, wherein the aqueous phase resulting from the extraction treatment is subjected to a stripping treatment comprising:
the dilute formaldehyde solution obtained from the extraction treatment enters a stripping tower to remove light ester components in the formaldehyde aqueous solution;
The gas phase at the top of the stripping tower is cooled to a preset temperature through circulating water, and the condensate is returned to the extraction tower after being boosted;
the stripping tower reboiler of the stripping tower adopts low-pressure steam as a heat source, and tower bottom liquid of the stripping tower is pumped and pressurized to remove the dilute formaldehyde recovery system.
7. The method of claim 1, wherein the azeotropic distillation treatment and the extractive distillation treatment are carried out by a baffle rectifying tower, a vertical baffle is arranged in the middle part of the baffle rectifying tower, the rectifying tower is divided into an upper public rectifying section, a lower public stripping section, a rectifying feeding section and a side extraction section on two sides of the baffle, methyl acrylate crude product gas after the light removal treatment and water serving as an extractant enter from the rectifying feeding section, and the rectifying feeding section plays the role of a primary fractionating tower to separate light components and heavy components; the separation of light components and intermediate components is realized in the public rectifying section, and the compressed and heated gas at the top of the tower is used as a reboiler heat source for light removal treatment; the separation of intermediate components and heavy components is realized in the public stripping section, and formaldehyde-rich solution in the tower bottom is sent to the extraction treatment after being cooled by water; the intermediate component methanol is obtained in the side offtake section.
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| CN112409178A (en) * | 2020-11-25 | 2021-02-26 | 西南化工研究设计院有限公司 | Method for preparing methyl methacrylate by taking methyl acetate as raw material |
| CN112374989B (en) * | 2020-11-25 | 2022-05-17 | 西南化工研究设计院有限公司 | Separation method of mixture containing formaldehyde and methanol |
| CN113651695B (en) * | 2021-08-17 | 2024-02-06 | 天津天南同创科技发展有限公司 | Separation and refining method for preparing methyl acetate from industrial tail gas |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103524345A (en) * | 2013-10-23 | 2014-01-22 | 上海浦景化工技术有限公司 | Product separation process for preparing methyl acrylate from methyl acetate |
| CN103833551A (en) * | 2012-11-27 | 2014-06-04 | 华东理工大学工程设计研究院有限公司 | Separation equipment and separation method of methyl methacrylate (MMA) |
| CN107337600A (en) * | 2017-07-04 | 2017-11-10 | 湖北三里枫香科技有限公司 | A kind of method and process unit of methanol and methyl acetate production methyl methacrylate |
| CN108129315A (en) * | 2017-12-19 | 2018-06-08 | 万华化学集团股份有限公司 | A kind of method and application that formaldehyde and methanol are removed from the logistics containing carboxylate |
| CN110981727A (en) * | 2019-12-06 | 2020-04-10 | 西南化工研究设计院有限公司 | Methyl methacrylate synthesis process |
| CN212532808U (en) * | 2020-06-22 | 2021-02-12 | 北京旭阳科技有限公司 | Methyl acrylate crude product gas separation equipment |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3971974B2 (en) * | 2002-09-03 | 2007-09-05 | 三菱化学株式会社 | Method for producing (meth) acrylic acids |
| DE102005010587A1 (en) * | 2005-03-08 | 2006-06-08 | Basf Ag | Preparing alkyl ester of (meth)acrylic acid comprises supplying (meth)acrylic acid, alkanol and catalyst to reaction zone, adding discharged mixture to rectification unit, supplying a partial flow of sump stream and isolating streams |
| US20130085303A1 (en) * | 2011-10-03 | 2013-04-04 | Celanese International Corporation | Processes for Producing Acrylic Acids and Acrylates |
| US20130317254A1 (en) * | 2012-05-25 | 2013-11-28 | Celanese International Corporation | Process for Producing Acrylic Acids and Acrylates |
| US20160090348A1 (en) * | 2014-09-30 | 2016-03-31 | Basf Se | Preparation of c8-c24 alkyl (meth)acrylates |
-
2020
- 2020-06-22 CN CN202010573201.6A patent/CN111574375B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103833551A (en) * | 2012-11-27 | 2014-06-04 | 华东理工大学工程设计研究院有限公司 | Separation equipment and separation method of methyl methacrylate (MMA) |
| CN103524345A (en) * | 2013-10-23 | 2014-01-22 | 上海浦景化工技术有限公司 | Product separation process for preparing methyl acrylate from methyl acetate |
| CN107337600A (en) * | 2017-07-04 | 2017-11-10 | 湖北三里枫香科技有限公司 | A kind of method and process unit of methanol and methyl acetate production methyl methacrylate |
| CN108129315A (en) * | 2017-12-19 | 2018-06-08 | 万华化学集团股份有限公司 | A kind of method and application that formaldehyde and methanol are removed from the logistics containing carboxylate |
| CN110981727A (en) * | 2019-12-06 | 2020-04-10 | 西南化工研究设计院有限公司 | Methyl methacrylate synthesis process |
| CN212532808U (en) * | 2020-06-22 | 2021-02-12 | 北京旭阳科技有限公司 | Methyl acrylate crude product gas separation equipment |
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