CN116337837A - Component detection and separation device and method in maleic anhydride production process - Google Patents
Component detection and separation device and method in maleic anhydride production process Download PDFInfo
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- FPYJFEHAWHCUMM-UHFFFAOYSA-N maleic anhydride Chemical compound O=C1OC(=O)C=C1 FPYJFEHAWHCUMM-UHFFFAOYSA-N 0.000 title claims abstract description 81
- 238000000034 method Methods 0.000 title claims abstract description 45
- 238000000926 separation method Methods 0.000 title claims abstract description 36
- 238000001514 detection method Methods 0.000 title claims abstract description 30
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 28
- 238000010521 absorption reaction Methods 0.000 claims abstract description 82
- 238000005192 partition Methods 0.000 claims abstract description 78
- 238000004821 distillation Methods 0.000 claims abstract description 62
- 239000002904 solvent Substances 0.000 claims abstract description 56
- 238000003795 desorption Methods 0.000 claims abstract description 36
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 26
- 238000001069 Raman spectroscopy Methods 0.000 claims abstract description 17
- 239000006227 byproduct Substances 0.000 claims abstract description 16
- 239000000203 mixture Substances 0.000 claims abstract description 8
- 230000003647 oxidation Effects 0.000 claims description 22
- 238000007254 oxidation reaction Methods 0.000 claims description 22
- IJDNQMDRQITEOD-UHFFFAOYSA-N n-butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 claims description 21
- 239000007791 liquid phase Substances 0.000 claims description 19
- 239000007788 liquid Substances 0.000 claims description 18
- 239000012071 phase Substances 0.000 claims description 17
- 239000000047 product Substances 0.000 claims description 12
- 238000005406 washing Methods 0.000 claims description 9
- 238000010992 reflux Methods 0.000 claims description 8
- 239000000463 material Substances 0.000 claims description 6
- 238000011144 upstream manufacturing Methods 0.000 claims description 6
- 150000008064 anhydrides Chemical class 0.000 claims description 5
- 238000005194 fractionation Methods 0.000 claims description 5
- 238000010438 heat treatment Methods 0.000 claims description 4
- 238000001816 cooling Methods 0.000 claims description 2
- 230000003134 recirculating effect Effects 0.000 claims description 2
- 230000008878 coupling Effects 0.000 claims 1
- 238000010168 coupling process Methods 0.000 claims 1
- 238000005859 coupling reaction Methods 0.000 claims 1
- 230000008569 process Effects 0.000 abstract description 25
- 238000001237 Raman spectrum Methods 0.000 abstract description 8
- 230000000694 effects Effects 0.000 abstract description 8
- 238000005265 energy consumption Methods 0.000 abstract description 7
- 230000007062 hydrolysis Effects 0.000 abstract description 6
- 238000006460 hydrolysis reaction Methods 0.000 abstract description 6
- 238000002425 crystallisation Methods 0.000 abstract description 2
- 230000008025 crystallization Effects 0.000 abstract description 2
- 239000007789 gas Substances 0.000 description 41
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 30
- 238000011084 recovery Methods 0.000 description 12
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 description 10
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 10
- 239000000523 sample Substances 0.000 description 5
- DOIRQSBPFJWKBE-UHFFFAOYSA-N dibutyl phthalate Chemical compound CCCCOC(=O)C1=CC=CC=C1C(=O)OCCCC DOIRQSBPFJWKBE-UHFFFAOYSA-N 0.000 description 4
- 238000005259 measurement Methods 0.000 description 4
- WFDIJRYMOXRFFG-UHFFFAOYSA-N Acetic anhydride Chemical compound CC(=O)OC(C)=O WFDIJRYMOXRFFG-UHFFFAOYSA-N 0.000 description 3
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 3
- LGRFSURHDFAFJT-UHFFFAOYSA-N Phthalic anhydride Natural products C1=CC=C2C(=O)OC(=O)C2=C1 LGRFSURHDFAFJT-UHFFFAOYSA-N 0.000 description 3
- JHIWVOJDXOSYLW-UHFFFAOYSA-N butyl 2,2-difluorocyclopropane-1-carboxylate Chemical compound CCCCOC(=O)C1CC1(F)F JHIWVOJDXOSYLW-UHFFFAOYSA-N 0.000 description 3
- 238000005260 corrosion Methods 0.000 description 3
- 230000007797 corrosion Effects 0.000 description 3
- 238000007701 flash-distillation Methods 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 2
- VZCYOOQTPOCHFL-OWOJBTEDSA-N Fumaric acid Chemical compound OC(=O)\C=C\C(O)=O VZCYOOQTPOCHFL-OWOJBTEDSA-N 0.000 description 2
- 238000004566 IR spectroscopy Methods 0.000 description 2
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 2
- WERYXYBDKMZEQL-UHFFFAOYSA-N butane-1,4-diol Chemical compound OCCCCO WERYXYBDKMZEQL-UHFFFAOYSA-N 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 238000001704 evaporation Methods 0.000 description 2
- 230000008020 evaporation Effects 0.000 description 2
- 230000003301 hydrolyzing effect Effects 0.000 description 2
- 239000012535 impurity Substances 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000013307 optical fiber Substances 0.000 description 2
- 239000003960 organic solvent Substances 0.000 description 2
- 238000012856 packing Methods 0.000 description 2
- XNGIFLGASWRNHJ-UHFFFAOYSA-N phthalic acid Chemical compound OC(=O)C1=CC=CC=C1C(O)=O XNGIFLGASWRNHJ-UHFFFAOYSA-N 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- VZCYOOQTPOCHFL-UHFFFAOYSA-N trans-butenedioic acid Natural products OC(=O)C=CC(O)=O VZCYOOQTPOCHFL-UHFFFAOYSA-N 0.000 description 2
- 229920006337 unsaturated polyester resin Polymers 0.000 description 2
- BJEPYKJPYRNKOW-REOHCLBHSA-N (S)-malic acid Chemical compound OC(=O)[C@@H](O)CC(O)=O BJEPYKJPYRNKOW-REOHCLBHSA-N 0.000 description 1
- VXNZUUAINFGPBY-UHFFFAOYSA-N 1-Butene Chemical compound CCC=C VXNZUUAINFGPBY-UHFFFAOYSA-N 0.000 description 1
- OFOBLEOULBTSOW-UHFFFAOYSA-N Propanedioic acid Natural products OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 description 1
- 239000006096 absorbing agent Substances 0.000 description 1
- 238000009825 accumulation Methods 0.000 description 1
- 150000001336 alkenes Chemical class 0.000 description 1
- BJEPYKJPYRNKOW-UHFFFAOYSA-N alpha-hydroxysuccinic acid Natural products OC(=O)C(O)CC(O)=O BJEPYKJPYRNKOW-UHFFFAOYSA-N 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- IAQRGUVFOMOMEM-UHFFFAOYSA-N butene Natural products CC=CC IAQRGUVFOMOMEM-UHFFFAOYSA-N 0.000 description 1
- UBAZGMLMVVQSCD-UHFFFAOYSA-N carbon dioxide;molecular oxygen Chemical compound O=O.O=C=O UBAZGMLMVVQSCD-UHFFFAOYSA-N 0.000 description 1
- 239000003054 catalyst Substances 0.000 description 1
- 239000013064 chemical raw material Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000008602 contraction Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 239000012847 fine chemical Substances 0.000 description 1
- 239000001530 fumaric acid Substances 0.000 description 1
- 125000000524 functional group Chemical group 0.000 description 1
- 229920006158 high molecular weight polymer Polymers 0.000 description 1
- 238000002329 infrared spectrum Methods 0.000 description 1
- 239000000314 lubricant Substances 0.000 description 1
- VZCYOOQTPOCHFL-UPHRSURJSA-N maleic acid Chemical compound OC(=O)\C=C/C(O)=O VZCYOOQTPOCHFL-UPHRSURJSA-N 0.000 description 1
- 239000011976 maleic acid Substances 0.000 description 1
- 239000001630 malic acid Substances 0.000 description 1
- 235000011090 malic acid Nutrition 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- -1 n-butane oxygen carbon monoxide Chemical compound 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- JRZJOMJEPLMPRA-UHFFFAOYSA-N olefin Natural products CCCCCCCC=C JRZJOMJEPLMPRA-UHFFFAOYSA-N 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000004014 plasticizer Substances 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 238000004064 recycling Methods 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 230000001172 regenerating effect Effects 0.000 description 1
- 230000008929 regeneration Effects 0.000 description 1
- 238000011069 regeneration method Methods 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 230000009466 transformation Effects 0.000 description 1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
- G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
- G01N21/65—Raman scattering
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/14—Fractional distillation or use of a fractionation or rectification column
- B01D3/143—Fractional distillation or use of a fractionation or rectification column by two or more of a fractionation, separation or rectification step
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/14—Fractional distillation or use of a fractionation or rectification column
- B01D3/32—Other features of fractionating columns ; Constructional details of fractionating columns not provided for in groups B01D3/16 - B01D3/30
- B01D3/322—Reboiler specifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/42—Regulation; Control
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/10—Process efficiency
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- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Health & Medical Sciences (AREA)
- Biochemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Analytical Chemistry (AREA)
- Physics & Mathematics (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Nuclear Medicine, Radiotherapy & Molecular Imaging (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention provides a component detection and separation device and method in the maleic anhydride production process. The component detection in the maleic anhydride production process adopts a Raman spectrometer, the Raman spectrum is insensitive to a water absorption band, the outlet of the maleic anhydride reactor forms water content, the detection accuracy is improved by using the Raman spectrometer, and the guarantee is provided for the parameter adjustment of the maleic anhydride absorption tower. The maleic anhydride separating device is a maleic anhydride pre-distillation tower and a desorption tower or adopts a partition wall tower (DWC) to couple the maleic anhydride pre-distillation tower and the desorption tower, and compared with the conventional process, the maleic anhydride separating device has the advantage that the equipment investment and the thermodynamic efficiency are obviously improved under the condition of equivalent energy consumption. The invention can effectively detect the outlet composition of the reactor, control the water content at the bottom of the absorption tower, prevent the blockage of equipment and systems caused by crystallization of byproducts generated by hydrolysis of maleic anhydride and absorption solvent, improve the separation effect, save the equipment investment and reduce the energy consumption.
Description
Technical Field
The invention relates to the field of maleic anhydride process optimization, in particular to a component detection and separation device and method in the maleic anhydride production process.
Technical Field
Maleic anhydride is also called maleic anhydride and maleic anhydride, is an important organic chemical raw material and fine chemical product, and is the third largest anhydride next to phthalic anhydride and acetic anhydride. In recent years, the apparent consumption of maleic anhydride in China is continuously increased, and the maleic anhydride is mainly used for producing Unsaturated Polyester Resins (UPR) and 1, 4-Butanediol (BDO), and can also be used for producing plasticizers, surface coating malic acid, lubricants and the like. The production process route of maleic anhydride can be divided into 4 kinds of raw materials, namely a phthalic anhydride byproduct method, a benzene oxidation method, a C4 olefin oxidation method and an n-butane oxidation method. The maleic anhydride is produced by using n-butane as raw material, and the technological process mainly comprises catalytic oxidation, organic solvent absorption, desorption, product refining and regeneration and purification of solvent. The main side reactions in the catalytic oxidation process are as follows:
C 4 H 10 +4.5O 2 →4CO+5H 2 O
n-butane oxygen carbon monoxide water
C 4 H 10 +6.5O 2 →4CO 2 +5H 2 O
N-butane oxygen carbon dioxide water
The n-butane oxidation reactor outlet gas therefore contains a certain amount of moisture. The composition of the gas at the outlet of the reactor reflects the effect of the catalyst in the reactor and has a great influence on the stability of the subsequent process flow, so that online detection equipment is needed, and an online infrared spectrometer is adopted in the prior art to monitor the composition. However, infrared spectroscopy cannot detect homonuclear diatomic molecules, such as nitrogen and oxygen in the outlet gas, and water vapor can greatly interfere with the measurement. Therefore, it is necessary to develop a convenient and rapid component detection device in the maleic anhydride production process.
An important link in the maleic anhydride production process is an absorption and separation system, wherein in the absorption system, a lean solvent (generally dibutyl phthalate) absorbs maleic anhydride from maleic anhydride reaction rich gas to form a rich solvent, and the rich solvent enters a rich solvent tank and then is sent to a desorption tower. The desorption tower is operated under high vacuum, top outlet gas is condensed by a condenser at the top of the desorption tower, and then flows back to the desorption tower by a reflux pump at the top of the desorption tower. Maleic anhydride is laterally extracted from the top packing section and pumped to a crude anhydride storage tank through a lateral line discharge pump of a desorption tower, and a lean solvent at the bottom of the desorption tower is returned to the absorption tower for recycling after post-treatment. The existing absorption separation process in the maleic anhydride production process is also provided with a post flash tower, and the effect is to recover maleic anhydride in the solvent at the bottom of the desorption tower by using part of the rich solvent of the absorption tower and remove part of light component byproducts (acetic acid, acrylic acid and the like) and water in the rich solvent, so as to prevent maleic anhydride from hydrolyzing to generate maleic acid and fumaric acid, and organic solvent dibutyl phthalate from hydrolyzing to generate phthalic acid and butanol or decomposing phthalic anhydride and butene at high temperature. The lean solvent treated by the post flash tower and the desorption tower are fed into a heat exchanger and then are fed into a lean solvent post-treatment unit, the lean solvent is recycled to the absorption tower after being treated, and part of water and rich solvent of light components are removed and returned to a rich solvent tank. (the above prior art processes can be referred to in the patent documents: US5972174A, US6120654A, US6090245A, US6593495B1, US6730810B2, US6603042B 2).
The post flash tower is not provided with a condenser and a reboiler, liquid phase reflux at the top of the post flash tower is partially cooled to form liquid phase at the bottom of the post flash tower, and then the liquid phase is recycled to the top of the post flash tower, the liquid phase at the bottom of the post flash tower is the gas phase which is flashed after the lean solvent at the bottom of the desorption tower is heated, and the formed gas phase and liquid phase exchange substances and energy on a post flash tower plate, so that partial light component byproducts (acetic acid, acrylic acid and the like) and water are removed at the top of the post flash tower, and the purposes of saving energy and reducing maleic anhydride loss are realized. However, there is a problem in that a light component by-product (acetic acid, acrylic acid, etc.) and water remain partially in the rich solvent and enter the desorber together with the rich solvent. Acetic acid, acrylic acid and the like are corrosive, water can cause hydrolysis of maleic anhydride and solvent in a subsequent flow, and the density of the solvent is changed after hydrolysis byproducts enter the solvent, so that a centrifuge for regenerating and purifying the solvent cannot be separated normally. The accumulation of a certain amount of impurities in the solvent system may further esterify to form a high molecular weight polymer. The solvent is recycled in the whole device, so that the byproducts in the solvent can cause the blockage of the lower part of the filter, the valve can not be opened or closed, and the like, thereby greatly shortening the running period of the centrifugal machine, and some devices are blocked successively or leak due to corrosion of acid, and finally the centrifugal machine is forced to stop. (Yang Fan et al, gansu technology, 2011, 27 (8): 41-42) on the mechanism and solution of maleic anhydride by-product formation. Therefore, there is a need to develop a process apparatus for effectively removing light component byproducts (acetic acid, acrylic acid, etc.) and water from rich solvents in hopes of further reducing energy and material consumption.
Disclosure of Invention
Aiming at the problems existing in the prior art, the invention provides a component detection and separation device and method in the maleic anhydride production process, wherein the component detection device is a Raman spectrometer, the Raman spectrum is a novel detection method, the characteristic spectrum is characterized in that the peak shape is a peak, the characteristic is strong, whether a certain functional group or a certain substance exists can be clearly and intuitively judged through the characteristic peak, and the qualitative and quantitative determination are easy; from the environmental adaptability of the analysis instrument, the Raman spectrum adopts a laser light source, and has low requirements on a sample cell due to the scattering spectrum and low requirements on water resistance and moisture resistance of instrument parts due to the fact that water has no influence on Raman spectrum signals basically; therefore, the component detection equipment in the maleic anhydride production process adopts a Raman spectrum analysis technology, so that the problem of water interference in infrared spectrum measurement can be effectively solved, and the measurement accuracy (CN 201120165694.6) is improved; in the invention, the separation device in the maleic anhydride production process is a maleic anhydride front distillation tower and a desorption tower, or a partition wall tower (DWC) is adopted to couple the maleic anhydride front distillation tower and the desorption tower into one tower, so that the equipment investment and thermodynamic efficiency are obviously improved, and under the condition of equivalent energy consumption, most of light components and water in rich oil are distilled out from the front distillation tower or the prefractionation tower of the partition wall tower, so that byproducts in the subsequent process are reduced, and the maleic anhydride concentration of side line products in desorption is improved. The component detection equipment, the separation device and the process in the maleic anhydride production process can effectively detect the outlet composition of the reactor, prevent equipment and a system from being blocked due to crystallization of byproducts generated by hydrolysis of maleic anhydride and absorption solvent, improve the separation effect, save equipment investment and reduce energy consumption.
The present invention aims to solve, at least to some extent, two problems in the related art.
Therefore, one purpose of the invention is to provide a Raman spectrometer to replace an infrared spectrometer to detect the gas composition at the outlet of the reactor, solve the problem of water interference in infrared spectrometry and improve the measurement accuracy.
Another object of the present invention is to provide a prefractionator for distilling a major portion of the light components and water from the rich oil using a pre-distillation or dividing wall column to reduce byproducts from subsequent passes, improve separation efficiency, save equipment investment, and reduce energy consumption.
The invention first provides a component detection and separation device in maleic anhydride production process, which comprises:
the component detection device is arranged on a pipeline between the outlet of the upstream n-butane oxidation reactor and the absorption tower and is used for detecting the product composition of the upstream n-butane oxidation reactor, and the component detection device is a Raman spectrometer;
an absorption tower for receiving the reacted material of the n-butane oxidation reactor, and absorbing maleic anhydride therein by adopting a lean solvent to form a rich solvent at the bottom of the tower;
the separation equipment receives the rich solvent of the absorption tower and separates maleic anhydride in the rich solvent;
the separation equipment comprises a front distillation tower and a desorption tower, or adopts a partition tower which couples the maleic anhydride front distillation tower and the desorption tower;
the front distillation tower distills out most light components and water in the rich solvent so as to reduce byproducts of the subsequent flow; and the desorption tower analyzes the maleic anhydride in the rich solvent to obtain maleic anhydride products and lean solvent.
As a preferred embodiment of the invention, the front distillation column has a side offtake stream which enters the upper half of the stripper column and the front distillation column bottom offtake stream enters the lower half of the stripper column.
As a preferable mode of the invention, the front distillation column, the desorption column and the partition column are plate column, packed column or plate-packed mixed column.
As a preferable scheme of the invention, a partition board is arranged vertically in the partition board tower to divide the inner cavity of the partition board tower into a prefractionation section positioned at the left side of the partition board, a side line section positioned at the right side of the partition board, a public rectifying section positioned above the partition board and a public stripping section positioned below the partition board, and the partition board tower is provided with a feed inlet communicated with the prefractionation section, a side line outlet communicated with the side line section, a tower top outlet communicated with the public rectifying section and a tower kettle outlet communicated with the public stripping section.
As a preferable scheme of the invention, the height of the partition plate is 15% -80% of the tower height of the partition wall tower; the partition is arranged such that the ratio of the cross-sectional area of the prefractionation column section to the cross-sectional area of the side line section is (0.5-2): 1.
As a preferred embodiment of the present invention, the partition is installed at the upper portion of the divided wall column without a common rectifying section above the partition.
As a preferable mode of the present invention, a gas cooler and a switching cooler are provided in order in the flow direction on the line between the outlet of the upstream n-butane oxidation reactor and the absorption tower, and the component detecting device is provided on the line between the switching cooler and the absorption tower.
As a preferable scheme of the invention, the rich solvent at the bottom of the absorption tower enters a front distillation tower or a partition tower after being heated by a heat exchanger E3; the heat exchanger E3 adopts a desorption tower or a partition tower to obtain a lean solvent which supplies part or all of heat; the lean solvent is treated and purified after heat exchange by the heat exchanger E3 and then is recycled to the absorption tower.
The invention also provides a component detection and separation method in the maleic anhydride generation process by adopting the device, wherein the separation equipment comprises a front distillation tower and a desorption tower, and the method comprises the following steps:
the method comprises the steps of cooling outlet gas of a n-butane oxidation reactor, setting a Raman spectrometer for on-line detection of components, allowing cooled gas to enter from the bottom of an absorption tower, allowing lean solvent to enter from the top of the absorption tower, removing torch from the gas at the top of the absorption tower, allowing rich oil at the bottom of the absorption tower to enter a front distillation tower after passing through a heat exchanger, setting a condenser at the top of the front distillation tower, refluxing condensed liquid to a first tower plate of the front distillation tower, removing uncondensed gas phase to a post-treatment washing tower, setting a reboiler at the bottom of the front distillation tower, allowing the front distillation tower to have side liquid phase discharge and tower bottom liquid phase discharge, allowing side liquid anhydride discharge to enter into an upper half tower plate of the absorption tower, allowing the tower bottom liquid phase discharge to have lower maleic anhydride concentration, allowing the lower half tower plate of the absorption tower to enter, setting a condenser at the top of the absorption tower, allowing condensed liquid to flow back to the first tower plate of the uncondensed gas phase to enter into the post-treatment washing tower, setting a reboiler at the bottom of the absorption tower, allowing the side liquid to flow back to the first tower plate of the front distillation tower, heating high-temperature lean oil at the bottom of the front distillation tower, and recirculating the top of the absorption tower through a post-treatment unit.
The invention also provides another component detection and separation method in the maleic anhydride generation process by adopting the device, the separation equipment adopts a partition tower, the partition tower couples a distillation tower and a desorption tower before maleic anhydride, and the method comprises the following steps:
the method comprises the steps that after the outlet gas of the n-butane oxidation reactor is cooled, a Raman spectrometer is arranged for online detection of components, cooled gas enters from the bottom of an absorption tower, lean solvent enters from the top of the absorption tower, gas at the top of the absorption tower is removed from a torch, rich oil at the bottom of the absorption tower enters a partition tower through a feed inlet of a pre-fractionation section of the partition tower after passing through a heater, a condenser is arranged at the top of a side-line section of the partition tower, a reboiler is arranged at the bottom of the partition tower, liquid condensed by the condenser flows back to a first column plate of a side-line section of the partition tower, liquid on the upper column plate of the side-line section of the partition tower is introduced into the first column plate of the pre-fractionation section, uncondensed gas phase is removed from a post-treatment washing tower, the side-line section of the partition tower is discharged into maleic anhydride product, and high-temperature lean oil at the bottom of the absorption tower is recycled to the top of the absorption tower through a post-treatment unit.
The invention has the outstanding technical effects that:
(1) The invention can be applied to new devices, and can also be used for carrying out technical transformation on some maleic anhydride production devices. After the invention is adopted, not only all functions of the original device can be realized, but also water and light component acid entering a desorption tower are greatly reduced, the problem of equipment and system blockage caused by byproducts generated by corrosion and hydrolysis of subsequent equipment is relieved, the operation period of the subsequent solvent recovery device can be prolonged, and the product loss is reduced.
(2) The speed and the accuracy of detection can be improved, and the separation effect is improved.
(3) Has the advantages of reducing investment of production equipment.
Drawings
FIG. 1 shows one of the component detection and separation processes in the maleic anhydride production process of the present invention;
FIG. 2 shows a second component detection and separation process in the maleic anhydride production process of the present invention.
The main device codes in the figure are as follows:
e1-gas cooler E2-switching cooler
A1-Raman spectrometer C1-absorption tower
E3-heat exchanger C2-front distillation column
E4-front distillation column condenser E5-front distillation column reboiler
C3-desorber E6-desorber condenser
E7-desorber reboiler C4-bulkhead column
E8-dividing wall column side stream condenser E9-dividing wall column reboiler
Detailed Description
The following describes specific embodiments of the present invention in detail. It should be understood that the specific embodiments described herein are for purposes of illustration and explanation only and are not intended to limit the present invention, as examples are set forth in the process flows shown in fig. 1 and 2.
In the process of FIG. 1, the outlet gas of the n-butane oxidation reactor is cooled by a gas cooler E1 and a switching cooler E2 and then is arranged on an on-line detector, the on-line detector is a Raman spectrum A1, the cooled gas enters from the bottom of an absorption tower C1, a lean solvent enters from the top of the absorption tower, the gas at the top of the absorption tower is removed from a torch, the rich oil at the bottom of the absorption tower enters a front distillation tower C2 after passing through a heat exchanger E3, a condenser E4 is arranged at the top of the front distillation tower, the condensed liquid flows back to a first tray of the front distillation tower, the uncondensed gas phase is removed from a post-treatment washing tower, a reboiler E5 is arranged at the bottom of the front distillation tower C2, the front distillation tower C2 is provided with a side line liquid phase discharge and a tower bottom liquid phase discharge, the side line discharge maleic anhydride concentration is relatively high, the side line discharge maleic anhydride enters the upper half tray of the absorption tower C3, the liquid phase discharge maleic anhydride concentration of the tower bottom is relatively low, the condensed liquid flows back to the first tray of the absorption tower C3, the uncondensed gas phase is removed from the post-treatment washing tower, E7 is arranged at the bottom of the absorption tower, the reboiler is discharged from the side stream to the top of the absorption tower C1 after being heated by the high-temperature unit after the distillation tower is recycled.
In the process of fig. 2, the outlet gas of the n-butane oxidation reactor is cooled by a gas cooler E1 and a switching cooler E2 and then is arranged on an online detector, the online detector is a Raman spectrum A1, the cooled gas enters from the bottom of an absorption tower C1, a lean solvent enters from the top of the absorption tower, the gas at the top of the absorption tower is discharged to a torch, the rich oil at the bottom of the absorption tower enters a separation wall tower C4 through a feed inlet of a prefractionation section after passing through a heater E3, a condenser E8 is arranged at the top of a side line section of the separation wall tower, a reboiler E9 is arranged at the bottom of the separation wall tower, liquid condensed by the condenser E8 flows back to a first column plate of the side line section of the separation wall tower, liquid on the upper column plate of the side line section of the separation wall tower is introduced into the first column plate of the prefractionation section, uncondensed gas phase is discharged to a washing column for aftertreatment, the side line section of the separation wall tower is discharged to be maleic anhydride, and the high-temperature lean oil at the bottom of the bottom is discharged to E3, heated to the feed stream of the pre-fractionation section of the separation wall tower, and then the liquid is recycled to the top of the absorption tower C1 through a post-treatment unit.
The front distillation column and the desorption column or the dividing wall column in fig. 1 and 2 are a tray column, a packed column or a tray-packed mixed column.
In fig. 2, a partition board is arranged vertically in the partition board tower to divide the inner cavity of the partition board tower into a prefractionation section positioned at the left side of the partition board, a side line section positioned at the right side of the partition board, a public rectification section positioned above the partition board and a public stripping section positioned below the partition board, the height of the partition board is 15% -80% of the height of the partition board tower, and preferably, the partition board is arranged at the upper part of the partition board tower without the public rectification section above the partition board; the partition plate is arranged so that the ratio of the cross-sectional area of the prefractionation column section to the cross-sectional area of the side line section is (0.5-2): 1; the operation pressure of the front distillation tower and the desorption tower or the partition tower is 2 kPa-20 kPa, the tower top temperature is 65-90 ℃, and the tower bottom temperature is 140-220 ℃. The side stream of the front distillation tower enters the upper half tray of the desorption tower, and the bottom stream of the front distillation tower enters the lower half tray of the desorption tower.
Example 1
The new process of the invention for producing maleic anhydride in 2.1 ten thousand tons year is compared with the original post flash evaporation process.
The process of fig. 1: the outlet gas of the n-butane oxidation reactor is generally cooled to 280 ℃ through a gas cooler E1 and then enters an absorption tower from the bottom of the absorption tower C1 after being cooled to 130 ℃ through a switching cooler E2, an optical fiber probe of a Raman spectrometer is arranged on a pipeline between the switching cooler E2 and the absorption tower C1, and the probe is connected with an online Raman spectrometer A1 to realize online detection. Water at 1670cm -1 Has weaker Raman peak at 3200-3400cm -1 There appears a distinct Raman band, a plurality of characteristic peaks in the Raman spectrum of maleic anhydride, of which 1844cm -1 The characteristic peak is the highest, is maleic anhydride (RCO) 2 The characteristic peak generated by symmetrical expansion and contraction of C=O has no other anhydride substances in impurities, so that the characteristic peak is used for qualitative and quantitative maleic anhydride, and the method is high in sensitivity, convenient and quick. The absorption lean solvent enters from the top of the tower, the number of absorption tower plates is 25, part of discharged material from the bottom of the tower is cooled to 45-60 ℃ and then is circulated back to the 16 th tower plate of the absorption tower, and the other part of enriched oil 16745kg/h at the bottom of the tower is added by a heat exchanger E3After heating to 175 ℃, the mixture enters a 3 rd column plate of a front distillation column C2, the front distillation column is a plate column, the form of the column plate is not limited, the number of the column plates is 4, the gas phase is discharged for 100kg/h, the mass recovery rate of water in the gas phase is 95.5%, the mass recovery rate of acetic acid is 87.8%, the mass recovery rate of acrylic acid is 59.1% (the gas phase is discharged from the top of a rear flash distillation column in the original feeding process, the mass recovery rate of water is 73.2%, the mass recovery rate of acetic acid is 12.9%, the mass recovery rate of acrylic acid is 5.4%), and the front distillation column C2 is provided with a 2 nd column plate liquid side stream discharge for 1500kg/h and a column kettle liquid phase discharge. The desorber C3 is a packed tower, the packing model is not limited, the number of theoretical plates is 13, the lateral line liquid phase discharge of the front distillation tower C2 enters the 6 th plate of the desorber, the tower kettle liquid phase discharge of the front distillation tower C2 enters the 8 th plate of the desorber, 2648kg/h of the lateral line liquid phase discharge of the 4 th plate of the desorber is maleic anhydride product, the purity is 99.98%wt, and the high-temperature lean oil at the tower bottom is recycled to the top of the absorber C1 after the feeding stream of the distillation tower is heated before E3 is removed at 210 ℃.
Front distillation column operating parameters: the pressure at the top of the tower is 2kPa, the reflux ratio is 10, the temperature of a condenser E4 is 69 ℃, and the temperature of a tower bottom reboiler E5 is 164 ℃; the pressure at the top of the desorption tower is 2kPa, the reflux ratio is 13.4, the temperature of the condenser E6 is 73 ℃, and the temperature of the tower bottom reboiler E7 is 210 ℃.
The process of fig. 2: the outlet gas of the n-butane oxidation reactor is generally cooled to 280 ℃ through a gas cooler E1 and then cooled to 130 ℃ through a switching cooler E2, the gas enters an absorption tower from the bottom of the absorption tower C1, an optical fiber probe of a Raman spectrometer is arranged on a pipeline between the E2 and the C1, and the probe is connected with an online Raman spectrometer A1 to realize online detection. The absorption lean solvent enters from the top of the tower, the theoretical plates of the absorption tower are 9, part of discharged materials at the bottom of the tower is cooled to 45-60 ℃ and then is circulated back to the 16 th tower plate of the absorption tower, and the other part of the enriched oil 16745kg/h at the bottom of the tower is heated to 175 ℃ through a heat exchanger E3 and then enters into a feed inlet of a prefractionation section of a partition tower C4. The height of the partition tower partition plate is 30% of the height of the partition tower, the partition plate is arranged to ensure that the ratio of the cross section area of the prefractionation tower section to the cross section area of the side line section is 1:1, 4 column plates are arranged in the prefractionation section like the front distillation tower in the process of fig. 1, the column plates are not limited, the partition plate is preferably arranged at the upper part of the partition tower and is completely independent from the line section, a condenser is arranged in the prefractionation section, a condenser is arranged in the side line section, a reboiler is arranged at the bottom of the column, the gas phase of the top of the prefractionation section is discharged at 99kg/h, the mass recovery rate of water in the gas phase is 99.8%, the mass recovery rate of acetic acid is 94.6%, the mass recovery rate of acrylic acid is 77.7% (the gas phase of the top of the flash evaporation tower is discharged at 97kg/h in the original flow of the same feeding, the mass recovery rate of acetic acid is 12.9%, and the mass recovery rate of acrylic acid is 5.4%). The liquid phase material 2648kg/h of the 4 th plate of the side line section of the partition tower is maleic anhydride product, the purity is 99.96%wt, and the high-temperature lean oil at the bottom of the tower is recycled to the top of the absorption tower C1 through a post-treatment unit after the E3-heating pre-distillation tower feeding stream is removed from the 210 ℃.
Partition column prefractionation parameters of operation: the pressure at the top of the tower is 2kPa, the reflux ratio is 8.7, and the temperature of the condenser E4 is 71 ℃; dividing wall column side stream operating parameter solution: the pressure at the top of the column was 2kPa, the reflux ratio was 13.5, the temperature of the condenser E6 was 72℃and the temperature of the reboiler at the bottom of the column was 210 ℃.
Comparison of energy consumption of the flash distillation process after the original flow and the processes of FIG. 1 and FIG. 2
The above table shows that the process of fig. 1 and 2 greatly improves the separation effect of light components (water, acetic acid and acrylic acid) in the pretreatment tower (the post flash distillation tower, the pre-distillation tower and the partition tower pre-distillation section) under the condition of equivalent total energy consumption, reduces corrosion of subsequent process equipment and pipelines and byproducts generated by hydrolysis in the subsequent process, prolongs the operation period of the whole device, and has the optimal process of fig. 2, namely reduces equipment investment and has the best separation effect of the light components.
The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the specific details of the above embodiments, and various simple modifications such as various special operations of the dividing wall column can be made to the technical solution of the present invention within the scope of the technical concept of the present invention, and all the simple modifications fall within the scope of the present invention.
In addition, the specific features described in the above embodiments may be combined in any suitable manner, and in order to avoid unnecessary repetition, various possible combinations are not described further.
Moreover, any combination of the various embodiments of the invention can be made without departing from the spirit of the invention, which should also be considered as disclosed herein.
Claims (10)
1. A component detection and separation device in maleic anhydride production process is characterized by comprising:
the component detection device is arranged on a pipeline between the outlet of the upstream n-butane oxidation reactor and the absorption tower and is used for detecting the product composition of the upstream n-butane oxidation reactor, and the component detection device is a Raman spectrometer;
an absorption tower for receiving the reacted material of the n-butane oxidation reactor, and absorbing maleic anhydride therein by adopting a lean solvent to form a rich solvent at the bottom of the tower;
the separation equipment receives the rich solvent of the absorption tower and separates maleic anhydride in the rich solvent;
the separation equipment comprises a front distillation tower and a desorption tower, or adopts a partition tower which couples the maleic anhydride front distillation tower and the desorption tower;
the front distillation tower distills out most light components and water in the rich solvent so as to reduce byproducts of the subsequent flow; and the desorption tower analyzes the maleic anhydride in the rich solvent to obtain maleic anhydride products and lean solvent.
2. A component detecting and separating device in maleic anhydride production process as claimed in claim 1, wherein: the front distillation column has a side offtake stream which enters the upper half of the desorber and the front distillation column bottom offtake stream enters the lower half of the desorber.
3. A component detecting and separating device in maleic anhydride production process as claimed in claim 1, wherein: the front distillation tower, the desorption tower and the partition tower are plate type towers, packed towers or plate-packed mixed towers.
4. A component detecting and separating device in maleic anhydride production process as claimed in claim 1, wherein: the partition wall tower is internally provided with a partition plate which is vertically arranged so as to divide the inner cavity of the partition wall tower into a prefractionation section positioned on the left side of the partition plate, a side line section positioned on the right side of the partition plate, a public rectifying section positioned above the partition plate and a public stripping section positioned below the partition plate, wherein the partition wall tower is provided with a feed inlet communicated with the prefractionation section, a side line outlet communicated with the side line section, a tower top outlet communicated with the public rectifying section and a tower kettle outlet communicated with the public stripping section.
5. A component detecting and separating device in maleic anhydride production process as claimed in claim 4, wherein: the height of the partition plate is 15% -80% of the tower height of the partition wall tower; the partition is arranged such that the ratio of the cross-sectional area of the prefractionation column section to the cross-sectional area of the side line section is (0.5-2): 1.
6. A component detecting and separating device in maleic anhydride production process as claimed in claim 4, wherein: the partition board is arranged at the upper part of the partition wall tower, and a public rectifying section above the partition board is not arranged.
7. The device for detecting and separating components in maleic anhydride production according to claim 1, wherein a gas cooler and a switching cooler are sequentially provided in the flow direction in the line between the outlet of the upstream n-butane oxidation reactor and the absorption column, and the component detecting apparatus is provided in the line between the switching cooler and the absorption column.
8. The device for detecting and separating components in the maleic anhydride production process according to claim 1, wherein the rich solvent at the bottom of the absorption tower enters a front distillation tower or a partition tower after being heated by a heat exchanger E3; the heat exchanger E3 adopts a desorption tower or a partition tower to obtain a lean solvent which supplies part or all of heat; the lean solvent is treated and purified after heat exchange by the heat exchanger E3 and then is recycled to the absorption tower.
9. A method for detecting and separating components in a maleic anhydride production process using the apparatus according to claim 1, wherein the separation device comprises a front distillation column and a desorption column, the method comprising the steps of:
the method comprises the steps of cooling outlet gas of a n-butane oxidation reactor, setting a Raman spectrometer for on-line detection of components, allowing cooled gas to enter from the bottom of an absorption tower, allowing lean solvent to enter from the top of the absorption tower, removing torch from the gas at the top of the absorption tower, allowing rich oil at the bottom of the absorption tower to enter a front distillation tower after passing through a heat exchanger, setting a condenser at the top of the front distillation tower, refluxing condensed liquid to a first tower plate of the front distillation tower, removing uncondensed gas phase to a post-treatment washing tower, setting a reboiler at the bottom of the front distillation tower, allowing the front distillation tower to have side liquid phase discharge and tower bottom liquid phase discharge, allowing side liquid anhydride discharge to enter into an upper half tower plate of the absorption tower, allowing the tower bottom liquid phase discharge to have lower maleic anhydride concentration, allowing the lower half tower plate of the absorption tower to enter, setting a condenser at the top of the absorption tower, allowing condensed liquid to flow back to the first tower plate of the uncondensed gas phase to enter into the post-treatment washing tower, setting a reboiler at the bottom of the absorption tower, allowing the side liquid to flow back to the first tower plate of the front distillation tower, heating high-temperature lean oil at the bottom of the front distillation tower, and recirculating the top of the absorption tower through a post-treatment unit.
10. A method for detecting and separating components in a maleic anhydride production process using the apparatus according to claim 4, wherein the separation device employs a dividing wall column coupling a pre-maleic anhydride distillation column and a desorption column, the method comprising the steps of:
the method comprises the steps that after the outlet gas of the n-butane oxidation reactor is cooled, a Raman spectrometer is arranged for online detection of components, cooled gas enters from the bottom of an absorption tower, lean solvent enters from the top of the absorption tower, gas at the top of the absorption tower is removed from a torch, rich oil at the bottom of the absorption tower enters a partition tower through a feed inlet of a pre-fractionation section of the partition tower after passing through a heater, a condenser is arranged at the top of a side-line section of the partition tower, a reboiler is arranged at the bottom of the partition tower, liquid condensed by the condenser flows back to a first column plate of a side-line section of the partition tower, liquid on the upper column plate of the side-line section of the partition tower is introduced into the first column plate of the pre-fractionation section, uncondensed gas phase is removed from a post-treatment washing tower, the side-line section of the partition tower is discharged into maleic anhydride product, and high-temperature lean oil at the bottom of the absorption tower is recycled to the top of the absorption tower through a post-treatment unit.
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117504545A (en) * | 2024-01-08 | 2024-02-06 | 常州瑞华化工工程技术股份有限公司 | Device and method for obtaining maleic anhydride from gas phase containing maleic anhydride |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117504545A (en) * | 2024-01-08 | 2024-02-06 | 常州瑞华化工工程技术股份有限公司 | Device and method for obtaining maleic anhydride from gas phase containing maleic anhydride |
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