CN111603896B - Environmentally friendly device and process for efficient solvent recovery of maleic anhydride - Google Patents
Environmentally friendly device and process for efficient solvent recovery of maleic anhydride 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 129
- 239000002904 solvent Substances 0.000 title claims abstract description 101
- 238000011084 recovery Methods 0.000 title claims abstract description 91
- 238000000034 method Methods 0.000 title claims abstract description 49
- 230000008569 process Effects 0.000 title claims abstract description 43
- 238000003795 desorption Methods 0.000 claims abstract description 122
- 238000010521 absorption reaction Methods 0.000 claims abstract description 114
- 239000002250 absorbent Substances 0.000 claims abstract description 89
- 230000002745 absorbent Effects 0.000 claims abstract description 88
- 238000003860 storage Methods 0.000 claims abstract description 62
- 238000001816 cooling Methods 0.000 claims abstract description 52
- 238000004519 manufacturing process Methods 0.000 claims abstract description 35
- 238000000605 extraction Methods 0.000 claims description 170
- 239000000463 material Substances 0.000 claims description 166
- 239000007789 gas Substances 0.000 claims description 148
- 239000012071 phase Substances 0.000 claims description 45
- DOIRQSBPFJWKBE-UHFFFAOYSA-N dibutyl phthalate Chemical compound CCCCOC(=O)C1=CC=CC=C1C(=O)OCCCC DOIRQSBPFJWKBE-UHFFFAOYSA-N 0.000 claims description 36
- 239000012495 reaction gas Substances 0.000 claims description 22
- 239000000203 mixture Substances 0.000 claims description 20
- 239000002912 waste gas Substances 0.000 claims description 17
- 239000006096 absorbing agent Substances 0.000 claims description 14
- 239000000047 product Substances 0.000 claims description 14
- 238000009826 distribution Methods 0.000 claims description 10
- 238000010992 reflux Methods 0.000 claims description 9
- FLKPEMZONWLCSK-UHFFFAOYSA-N diethyl phthalate Chemical compound CCOC(=O)C1=CC=CC=C1C(=O)OCC FLKPEMZONWLCSK-UHFFFAOYSA-N 0.000 claims description 8
- 239000007788 liquid Substances 0.000 claims description 8
- MQHNKCZKNAJROC-UHFFFAOYSA-N dipropyl phthalate Chemical compound CCCOC(=O)C1=CC=CC=C1C(=O)OCCC MQHNKCZKNAJROC-UHFFFAOYSA-N 0.000 claims description 6
- 238000000926 separation method Methods 0.000 claims description 6
- NIQCNGHVCWTJSM-UHFFFAOYSA-N Dimethyl phthalate Chemical compound COC(=O)C1=CC=CC=C1C(=O)OC NIQCNGHVCWTJSM-UHFFFAOYSA-N 0.000 claims description 4
- GDCXITNLGXJUPZ-UHFFFAOYSA-N diethyl cyclohex-3-ene-1,2-dicarboxylate Chemical compound CCOC(=O)C1CCC=CC1C(=O)OCC GDCXITNLGXJUPZ-UHFFFAOYSA-N 0.000 claims description 3
- QWDBCIAVABMJPP-UHFFFAOYSA-N Diisopropyl phthalate Chemical compound CC(C)OC(=O)C1=CC=CC=C1C(=O)OC(C)C QWDBCIAVABMJPP-UHFFFAOYSA-N 0.000 claims description 2
- FBSAITBEAPNWJG-UHFFFAOYSA-N dimethyl phthalate Natural products CC(=O)OC1=CC=CC=C1OC(C)=O FBSAITBEAPNWJG-UHFFFAOYSA-N 0.000 claims description 2
- 229960001826 dimethylphthalate Drugs 0.000 claims description 2
- 230000007613 environmental effect Effects 0.000 claims description 2
- 239000007791 liquid phase Substances 0.000 claims description 2
- MGWAVDBGNNKXQV-UHFFFAOYSA-N diisobutyl phthalate Chemical compound CC(C)COC(=O)C1=CC=CC=C1C(=O)OCC(C)C MGWAVDBGNNKXQV-UHFFFAOYSA-N 0.000 claims 2
- QSAWQNUELGIYBC-UHFFFAOYSA-N cyclohexane-1,2-dicarboxylic acid Chemical compound OC(=O)C1CCCCC1C(O)=O QSAWQNUELGIYBC-UHFFFAOYSA-N 0.000 claims 1
- 238000004821 distillation Methods 0.000 claims 1
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Natural products C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 claims 1
- 239000013589 supplement Substances 0.000 claims 1
- 238000004064 recycling Methods 0.000 abstract description 17
- 230000000694 effects Effects 0.000 abstract description 7
- 239000012535 impurity Substances 0.000 abstract description 6
- 238000000746 purification Methods 0.000 abstract description 2
- 238000007670 refining Methods 0.000 abstract description 2
- 150000008065 acid anhydrides Chemical class 0.000 abstract 1
- 238000005260 corrosion Methods 0.000 abstract 1
- 230000007797 corrosion Effects 0.000 abstract 1
- 239000002699 waste material Substances 0.000 abstract 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 15
- VZCYOOQTPOCHFL-OWOJBTEDSA-N Fumaric acid Chemical compound OC(=O)\C=C\C(O)=O VZCYOOQTPOCHFL-OWOJBTEDSA-N 0.000 description 14
- UHOVQNZJYSORNB-UHFFFAOYSA-N Benzene Chemical compound C1=CC=CC=C1 UHOVQNZJYSORNB-UHFFFAOYSA-N 0.000 description 12
- VZCYOOQTPOCHFL-UHFFFAOYSA-N trans-butenedioic acid Natural products OC(=O)C=CC(O)=O VZCYOOQTPOCHFL-UHFFFAOYSA-N 0.000 description 11
- 239000000284 extract Substances 0.000 description 10
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 9
- 239000001530 fumaric acid Substances 0.000 description 7
- IJDNQMDRQITEOD-UHFFFAOYSA-N n-butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 description 7
- 230000001105 regulatory effect Effects 0.000 description 7
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 6
- 238000002156 mixing Methods 0.000 description 5
- SMZOUWXMTYCWNB-UHFFFAOYSA-N 2-(2-methoxy-5-methylphenyl)ethanamine Chemical compound COC1=CC=C(C)C=C1CCN SMZOUWXMTYCWNB-UHFFFAOYSA-N 0.000 description 4
- NIXOWILDQLNWCW-UHFFFAOYSA-N 2-Propenoic acid Natural products OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 4
- XTJFFFGAUHQWII-UHFFFAOYSA-N Dibutyl adipate Chemical compound CCCCOC(=O)CCCCC(=O)OCCCC XTJFFFGAUHQWII-UHFFFAOYSA-N 0.000 description 4
- LGRFSURHDFAFJT-UHFFFAOYSA-N Phthalic anhydride Natural products C1=CC=C2C(=O)OC(=O)C2=C1 LGRFSURHDFAFJT-UHFFFAOYSA-N 0.000 description 4
- OFOBLEOULBTSOW-UHFFFAOYSA-N Propanedioic acid Natural products OC(=O)CC(O)=O OFOBLEOULBTSOW-UHFFFAOYSA-N 0.000 description 4
- 230000008901 benefit Effects 0.000 description 4
- JHIWVOJDXOSYLW-UHFFFAOYSA-N butyl 2,2-difluorocyclopropane-1-carboxylate Chemical compound CCCCOC(=O)C1CC1(F)F JHIWVOJDXOSYLW-UHFFFAOYSA-N 0.000 description 4
- 230000018044 dehydration Effects 0.000 description 4
- 238000006297 dehydration reaction Methods 0.000 description 4
- 229940100539 dibutyl adipate Drugs 0.000 description 4
- VZCYOOQTPOCHFL-UPHRSURJSA-N maleic acid Chemical compound OC(=O)\C=C/C(O)=O VZCYOOQTPOCHFL-UPHRSURJSA-N 0.000 description 4
- 239000011976 maleic acid Substances 0.000 description 4
- 239000003960 organic solvent Substances 0.000 description 4
- 230000003647 oxidation Effects 0.000 description 4
- 238000007254 oxidation reaction Methods 0.000 description 4
- WFDIJRYMOXRFFG-UHFFFAOYSA-N Acetic anhydride Chemical compound CC(=O)OC(C)=O WFDIJRYMOXRFFG-UHFFFAOYSA-N 0.000 description 3
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 description 3
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 3
- 239000001569 carbon dioxide Substances 0.000 description 3
- 229910002092 carbon dioxide Inorganic materials 0.000 description 3
- 229910002091 carbon monoxide Inorganic materials 0.000 description 3
- 238000009833 condensation Methods 0.000 description 3
- 230000005494 condensation Effects 0.000 description 3
- 235000015110 jellies Nutrition 0.000 description 3
- 239000008274 jelly Substances 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 239000001301 oxygen Substances 0.000 description 3
- 229910052760 oxygen Inorganic materials 0.000 description 3
- 238000012856 packing Methods 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 150000008064 anhydrides Chemical class 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- 230000006837 decompression Effects 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 238000005265 energy consumption Methods 0.000 description 2
- 230000007774 longterm Effects 0.000 description 2
- XMTOUDRCWLYEHL-UHFFFAOYSA-N (2-bromo-3-ethoxy-6-fluorophenyl)boronic acid Chemical compound CCOC1=CC=C(F)C(B(O)O)=C1Br XMTOUDRCWLYEHL-UHFFFAOYSA-N 0.000 description 1
- 208000036828 Device occlusion Diseases 0.000 description 1
- MQIUGAXCHLFZKX-UHFFFAOYSA-N Di-n-octyl phthalate Natural products CCCCCCCCOC(=O)C1=CC=CC=C1C(=O)OCCCCCCCC MQIUGAXCHLFZKX-UHFFFAOYSA-N 0.000 description 1
- 239000003513 alkali Substances 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- BJQHLKABXJIVAM-UHFFFAOYSA-N bis(2-ethylhexyl) phthalate Chemical compound CCCCC(CC)COC(=O)C1=CC=CC=C1C(=O)OCC(CC)CCCC BJQHLKABXJIVAM-UHFFFAOYSA-N 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 230000003197 catalytic effect Effects 0.000 description 1
- 230000008859 change Effects 0.000 description 1
- 239000013064 chemical raw material Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 230000036571 hydration Effects 0.000 description 1
- 238000006703 hydration reaction Methods 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 230000008676 import Effects 0.000 description 1
- 239000002440 industrial waste Substances 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- XNGIFLGASWRNHJ-UHFFFAOYSA-L phthalate(2-) Chemical compound [O-]C(=O)C1=CC=CC=C1C([O-])=O XNGIFLGASWRNHJ-UHFFFAOYSA-L 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 230000002035 prolonged effect Effects 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000000630 rising effect Effects 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 230000001502 supplementing effect Effects 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
- 229920006337 unsaturated polyester resin Polymers 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 239000002351 wastewater Substances 0.000 description 1
- 238000004065 wastewater treatment Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
- B01D53/1487—Removing organic compounds
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
- B01D53/1425—Regeneration of liquid absorbents
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D53/00—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
- B01D53/14—Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by absorption
- B01D53/18—Absorbing units; Liquid distributors therefor
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D307/00—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom
- C07D307/02—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings
- C07D307/34—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members
- C07D307/56—Heterocyclic compounds containing five-membered rings having one oxygen atom as the only ring hetero atom not condensed with other rings having two or three double bonds between ring members or between ring members and non-ring members with hetero atoms or with carbon atoms having three bonds to hetero atoms with at the most one bond to halogen, e.g. ester or nitrile radicals, directly attached to ring carbon atoms
- C07D307/60—Two oxygen atoms, e.g. succinic anhydride
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D2252/00—Absorbents, i.e. solvents and liquid materials for gas absorption
- B01D2252/20—Organic absorbents
- B01D2252/205—Other organic compounds not covered by B01D2252/00 - B01D2252/20494
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Engineering & Computer Science (AREA)
- Analytical Chemistry (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
本发明公开了一种高效溶剂回收顺酐的环保装置及工艺，涉及酸酐类精制提纯技术领域，解决了顺酐回收过程回收率低、设备腐蚀性高的技术问题，其技术方案要点是该装置包括吸收塔、解吸塔、后闪蒸塔、尾气回收塔、离心萃取器、若干台换热器、机泵和储罐；其中吸收塔塔釜塔釜循环泵、富油储存罐采出口、后闪蒸塔塔釜泵、后闪蒸塔循环冷却泵和贫油储存罐采出口设置若干支路，有效保证了解吸塔进料中顺酐含量和循环吸收剂中杂质的含量，并充分利用系统中所含热量。通过该装置回收顺酐的工艺有效保证了顺酐的纯度达99.9%(wt)，顺酐的收率达98%以上，吸收剂的循环利用率达99.9%以上；该工艺相比现有溶剂吸收法处理工艺溶剂比更低，装置稳定性更好，大幅度降低废渣产生，效果显著，有利于在顺酐回收领域中推广应用。
The invention discloses an environmentally friendly device and process for efficiently recovering maleic anhydride with solvent, relates to the technical field of acid anhydride refining and purification, solves the technical problems of low recovery rate and high equipment corrosion in the recovery process of maleic anhydride, and the key points of the technical scheme are that the device includes an absorption tower, a desorption tower, a post-flash tower, a tail gas recovery tower, a centrifugal extractor, a plurality of heat exchangers, a pump and a storage tank; wherein the absorption tower kettle circulating pump, the oil-rich storage tank production outlet, the post-flash tower kettle pump, the post-flash tower circulating cooling pump and the lean oil storage tank production outlet are provided with a plurality of branches, effectively ensuring the content of maleic anhydride in the desorption tower feed and the content of impurities in the circulating absorbent, and making full use of the heat contained in the system. The process of recovering maleic anhydride by the device effectively ensures that the purity of maleic anhydride reaches 99.9% (wt), the yield of maleic anhydride reaches more than 98%, and the recycling rate of the absorbent reaches more than 99.9%; compared with the existing solvent absorption method treatment process, the process has a lower solvent ratio, better device stability, greatly reduces the generation of waste residue, and has a significant effect, which is conducive to the promotion and application in the field of maleic anhydride recovery.
Description
Technical Field
The disclosure relates to the technical field of anhydride refining and purification, in particular to an environment-friendly device and process for recycling maleic anhydride by using a high-efficiency solvent.
Background
Maleic anhydride is a common important organic chemical raw material, the consumption of which is inferior to that of phthalic anhydride and acetic anhydride, and is mainly used for producing unsaturated polyester resin, BDO, paint and the like, the maleic anhydride demand is vigorous in recent years, the market prospect is good, the BDO price of downstream products is continuously increased, and the import quantity is kept at a higher scale.
The maleic anhydride production process can be generally divided into two parts of an oxidation process and a post-treatment process, wherein the oxidation process can be divided into a benzene process and an n-butane process according to raw materials, the post-treatment process mainly comprises a water absorption process and a solvent absorption process, the benzene process occupies 65% of the productivity, and the n-butane process occupies about 35%. The price of benzene which is a raw material of maleic anhydride is high in the present year, so that the enterprise of benzene method maleic anhydride is lost, the production of a near-half device is stopped, the operating rate is kept around 2 years, the actual output is increased negatively, and the device of normal butane method has the trend of rapid development except for the advantages of low price of normal butane which is a raw material, high product yield, stable product quality, low energy consumption, high profit and the like.
The recovery of maleic anhydride from maleic anhydride reaction gas mainly comprises two processes of water absorption and solvent absorption, the former has the advantages of short flow, low equipment investment, mature process and the like, but the defects are that fumaric acid impurity is easy to generate due to improper temperature control during the absorption and dehydration operation. In addition to affecting the maleic anhydride yield of the device, the significant hazard of the large amount of fumaric acid is that fumaric acid is easily polymerized with acrylic acid into jelly, blocking the trays, and even causing the trays to fall off in severe cases. The existence of the polymer jelly seriously influences the efficiency of the tower, so that the energy consumption of the dehydration operation is increased, and the jelly cannot be removed by washing and needs to be steamed by alkali liquor, so that the wastewater quantity and the wastewater treatment difficulty are increased, and the dehydration process cannot be continuously carried out. The steam of the device is not easy to balance during intermittent operation, and the working strength of operators is also increased.
The solvent absorption is to send the gas phase mixture containing maleic anhydride obtained by the oxidation section reaction to an absorption tower, and to absorb all the mixture by using organic solvent with high boiling point, low viscosity, good chemical stability and weak affinity with water, and then to a desorption tower for decompression separation. The absorption process of the solvent absorption process does not have the process of synthesizing maleic anhydride by hydration of maleic anhydride, and even though a small amount of maleic anhydride is still generated in the reaction system and is further isomerized into fumaric acid, the generated amount is much less than that of the water absorption process, and the possibility of device blockage is also reduced greatly, so that the recovery rate of the maleic anhydride post-treatment process is 3 to 5 percent higher than that of the water absorption method, the operation stability of the device is improved, the production time is prolonged, and the economic benefit is improved. In addition, because there is no maleic anhydride water to synthesize maleic acid, there is no need of corresponding dehydration process, the amount of steam consumed by maleic anhydride post-treatment operation is reduced, the device can output more steam for external use, the recovery rate of maleic anhydride is improved, and the equipment investment is reduced.
US2014/0081036A1 is a patent application for the use of organic solvents, in particular dibutyl adipate, as a selective absorber of maleic anhydride. The patent teaches that maleic anhydride can be absorbed from a gas stream containing maleic anhydride at a suitable temperature and pressure using dibutyl adipate as an absorbent because maleic anhydride also has a higher solubility in dibutyl adipate solvent. The solvent is then regenerated by stripping the maleic anhydride from the dibutyl adipate solvent under vacuum conditions and at elevated temperature.
Chinese patented invention patent CN1062344 relates to the use of different types of organic solvents such as dioctyl phthalate or dewaxed oil from refineries to recover maleic anhydride from the catalytic oxidation of hydrocarbons.
Chinese patented invention patent CN102558113B discloses an improved process for recovering maleic anhydride from organic solvents, especially dibutyl phthalate. The absorption temperature is reduced by utilizing the stripping of hot air and the line drawing and cooling circulation of an absorption tower, the maleic anhydride absorption recovery rate is improved, and the content of light components such as acetic acid, acrylic acid and the like in the absorbent is reduced, but the implementation effect is not ideal.
Along with the call of energy conservation and emission reduction in China, the method is particularly important to change the defects of the technology for purifying maleic anhydride by the traditional solvent absorption method. The development of a novel environment-friendly process for absorbing and recycling maleic anhydride by using a high-efficiency solvent with stable operation and remarkable energy-saving and consumption-reducing effects can effectively improve the purity, yield and recycling rate of an absorbent of the maleic anhydride, and is particularly important.
Disclosure of Invention
The invention provides an environment-friendly device and process for recycling maleic anhydride by using a high-efficiency solvent, and aims to effectively improve the purity and yield of maleic anhydride, improve the recycling rate of an absorbent, ensure low equipment cost, stable operation effect, save energy and reduce consumption.
The technical aim of the disclosure is achieved by the following technical scheme:
An environment-friendly device for recycling maleic anhydride by using high-efficiency solvents comprises an absorption tower T1, a desorption tower T2, a post flash tower T3, a tail gas recycling tower T4, an extractor SE1, a reaction gas cooler E1, an absorbent circulating cooler E2, a desorption tower condenser E3, a desorption tower reboiler E4, a post flash tower preheater E5, a post flash tower circulating cooler E6, a lean solvent cooler E7, an absorption tower kettle circulating pump P1, a post flash tower kettle pump P2, a post flash tower circulating cooling pump P3, a rich oil storage tank V1, a lean oil storage tank V2 and an extraction premixing tank V3;
The reaction gas cooler E1, the absorbent circulating cooler E2, the desorber condenser E3, the desorber reboiler E4, the post flash tower preheater E5, the post flash tower circulating cooler E6, the lean solvent cooler E7, the absorber tower kettle circulating pump P1, the post flash tower kettle pump P2 and the post flash tower circulating cooling pump P3 all comprise a feed inlet and a discharge outlet;
The top of the absorption tower T1 is provided with an exhaust gas discharge port, a lean solvent feed port is arranged on the upper right side, an absorbent circulating cooling material feed port is arranged on the lower right side, a reactor outlet mixed gas feed port is arranged on the left side, and a tower kettle material outlet is arranged at the bottom;
The top of the desorption tower T2 is provided with a steam extraction port, the upper right side is provided with a reflux port, the upper left side is provided with a qualified maleic anhydride product extraction port, the lower left side is provided with a desorption tower rich oil feed port, the lower right side is provided with a desorption tower kettle steam feed port, and the bottom is provided with a desorption tower kettle material extraction port;
the top of the rear flash tower T3 is provided with a gas phase extraction port, the upper right side is provided with a rear flash tower circulating cooling material feed inlet, the left side is provided with a rear flash tower feed inlet, the lower right side is provided with a rear flash tower side line extraction port, and the bottom is provided with a tower kettle lean oil extraction port;
The top of the tail gas recovery tower T4 is provided with a waste gas extraction outlet, the right side is provided with a lean oil feed inlet of the tail gas recovery tower, the left side is provided with a gas phase feed inlet of the tail gas recovery tower, and the bottom is provided with a material extraction outlet of the tower kettle of the tail gas recovery tower;
The right side of the extractor SE1 is provided with an extractor feed inlet, the left side of the extractor SE1 is provided with a raffinate discharge outlet, and the bottom of the extractor SE1 is provided with an extraction lean oil discharge outlet;
The left side of the rich oil storage tank V1 is provided with a rich oil feed inlet for extracting rich oil from the tower kettle of the absorption tower the bottom is provided with a side stream extraction rich oil feed inlet of the rear flash tower, and the right side is provided with a rich oil extraction outlet;
the left side of the lean oil storage tank V2 is provided with a lean oil feed inlet, the top of the lean oil storage tank V2 is provided with an absorbent supplementing feed inlet, and the right side of the lean oil storage tank V2 is provided with a lean oil discharge outlet;
The upper left side of the extraction premixing tank V3 is provided with a lean oil feed inlet of the premixing tank, the lower left side is provided with an extractant feed inlet, and the bottom is provided with a mixed liquid discharge outlet;
The lean solvent feed inlet of the absorption tower is connected with the lean oil discharge outlet and the extraction lean oil discharge outlet, the absorbent circulating cooling material feed inlet is connected with the discharge outlet of the absorbent circulating cooler E2 and the material extraction outlet of the tail gas recovery tower kettle, the mixed gas feed inlet of the reactor outlet is connected with the discharge outlet of the reaction gas cooler E1, the material outlet of the absorption tower kettle is connected with the feed inlet of the absorption tower circulating pump P1, and the discharge outlet of the absorption tower circulating pump P1 is connected with the feed inlet of the absorbent circulating cooler E2, the rich oil feed inlet extracted by the absorption tower kettle and the feed inlet of the post flash tower circulating cooler E6;
The desorption tower is characterized in that the steam extraction port is connected with a feed port of a desorption tower condenser E3, the rich oil feed port of the desorption tower is connected with the rich oil extraction port, the desorption tower kettle steam feed port is connected with a discharge port of a desorption tower reboiler E4, the desorption tower kettle material extraction port is connected with a feed port of the desorption tower reboiler E4 and a feed port of a post flash tower preheater E5, and the discharge port of the desorption tower condenser E3 is connected with a reflux port and a gas phase feed port of a tail gas recovery tower;
The gas phase extraction port is connected with the gas phase feed port of the tail gas recovery tower, the circulating cooling material feed port of the rear flash tower is connected with the discharge port of the circulating cooler E6 of the rear flash tower, the feed port of the circulating cooling pump P3 of the rear flash tower is connected with the feed port of the circulating cooling pump P3 of the rear flash tower, the lean oil extraction port of the tower bottom is connected with the feed port of the tower bottom pump P2 of the rear flash tower, the discharge port of the tower bottom pump P2 of the rear flash tower is connected with the feed port of the circulating cooler E5 of the rear flash tower and the feed port of the lean solvent cooler E7 of the rear flash tower, and the discharge port of the circulating cooling pump P3 of the rear flash tower is connected with the feed port of the circulating cooler E6 of the rear flash tower and the rich oil extraction feed port of the side stream of the rear flash tower;
The lean oil feed inlet of the tail gas recovery tower is connected with the lean oil discharge outlet, the feed inlet of the extractor is connected with the mixed liquid discharge outlet, the lean oil feed inlet is connected with the discharge outlet of the lean solvent cooler E7, and the lean oil discharge outlet is connected with the lean oil feed inlet of the tail gas recovery tower, the lean solvent feed inlet and the lean oil feed inlet of the premixing tank.
Further, the total tray number of the absorption tower T1 is 9-40, the tray number is counted from top to bottom, and the feeding hole of the absorbent circulating cooling material is positioned at 40% -60% of the total tray number of the absorption tower T1.
Further, the total tray number of the desorption tower T2 is 22-45, the tray number is counted from top to bottom, wherein the rich oil feed inlet of the desorption tower is positioned at 40-55% of the total tray number of the desorption tower T2, and the qualified maleic anhydride product extraction outlet is positioned at 12-20% of the total tray number of the desorption tower T2.
Further, the number of tower plates of the post-flash tower T3 is 4-9, the number of tower plates is counted from top to bottom, and a side line extraction outlet of the post-flash tower is positioned at 1-2 tower plates upwards from the bottom of the post-flash tower T3.
An environment-friendly process for recycling maleic anhydride by using a high-efficiency solvent comprises the following steps:
S1, cooling maleic anhydride reactor outlet mixed gas through a reaction gas cooler E1, then enabling the cooled maleic anhydride reactor outlet mixed gas to enter the bottom of an absorption tower T1 through a reactor outlet mixed gas feed inlet, enabling a lean solvent to enter the top of the absorption tower T1 through a lean solvent feed inlet, enabling an absorbent circulating cooling material to enter the middle lower part of the absorption tower T1 through an absorbent circulating cooling material feed inlet, absorbing the mixture through an absorbent, and then enabling rich oil at the tower bottom of the absorption tower T1 to be extracted from a tower bottom material outlet through a discharge port of an absorption tower bottom circulating pump P1, wherein three extracted materials of the absorption tower bottom circulating pump P1 are respectively fed to a feed inlet of an absorbent circulating cooler E2, a rich oil extracted from the tower bottom of the absorption tower, and a feed inlet of a post flash evaporation tower circulating cooler E6;
S2, after the tower kettle rich oil sent to the absorber circulating cooler E2 from the tower kettle material outlet is cooled by the absorber circulating cooler E2, mixing the rich oil with the extracted material at the tail gas recovery tower kettle material extraction outlet in a pipeline, and then entering the middle lower part of the absorber T1 through the absorber circulating cooling material feed inlet;
S3, sending the material outlet of the tower bottom to the tower bottom rich oil of the rich oil feed inlet of the absorption tower bottom, mixing the material with the material extracted from the side stream extraction outlet of the post flash tower in a rich oil storage tank V1, extracting the material from the rich oil extraction outlet, dividing the extraction of the rich oil extraction outlet into two materials, respectively pumping the two materials into the rich oil feed inlet of the absorption tower and the post flash tower circulating cooler E6, rectifying in the absorption tower T2, extracting light components from the steam extraction outlet of the tower top, condensing part of the extraction of the steam extraction outlet through the absorption tower condenser E3, then entering the absorption tower T2 through a reflux port, and entering the tail gas recovery tower T4 through the gas phase feed inlet of the tail gas recovery tower, extracting qualified maleic anhydride from the qualified maleic anhydride product extraction outlet of the side stream of the absorption tower T2, and extracting absorbent from the material outlet of the absorption tower bottom;
s4, preheating a part of the absorbent extracted from the material extraction port of the desorption tower kettle by a post flash tower preheater E5, entering the post flash tower T3 through a post flash tower feed port for further desorption, reboiling the other part of the absorbent by a desorption tower reboiler E4, entering the desorption tower T2 through a desorption tower kettle steam feed port, extracting light components from the gas phase extraction port at the top of the post flash tower T3 by a side extraction port side extraction absorbent of the post flash tower, mixing the absorbent extracted from the side extraction port of the post flash tower with the rich oil of the tower kettle extracted from the material extraction port of the tower kettle and the rich oil extracted from the rich oil storage tank V1, cooling by a post flash tower circulating cooler E6, and then entering the top of the post flash tower T3 by a post flash tower circulating cooling material feed port as liquid phase reflux, and extracting lean solvent from the lean oil extraction port of the tower kettle;
S5, mixing the light components extracted from the steam extraction port and the gas phase extraction port, and then entering the bottom of a tail gas recovery tower T4 through a gas phase feed port of the tail gas recovery tower, cooling a lean solvent extracted from a lean oil extraction port of a tower kettle by a lean solvent cooler E7, and then partially extracting the lean solvent by a lean oil storage tank V2, and then entering the top of the tail gas recovery tower T4 through a lean oil feed port of the tail gas recovery tower;
S6, returning part of lean oil extracted from a lean oil extraction port of a tower kettle of the post-flash tower T3 to a post-flash tower preheater E5 to preheat feed, cooling the other part of lean oil by a lean solvent cooler E7 and then feeding the rest of lean oil into a lean oil feed port of a lean oil storage tank V2, cooling part of absorbent laterally extracted from a side extraction port of a post-flash tower side line by a post-flash tower circulating cooler E6, returning the cooled material feed port of the post-flash tower to the post-flash tower T3, and feeding the other part of absorbent laterally extracted from a side line of the post-flash tower into a rich oil storage tank V1;
S7, dividing the material at the outlet of the lean oil discharge port of the lean oil storage tank V2 into three materials, respectively entering a lean solvent feed port of the absorption tower T1, a lean oil feed port of the tail gas recovery tower and a lean oil feed port of the premixing tank of the extraction premixing tank V3, mixing the materials with fresh extractant entering from the extractant feed port through the extraction premixing tank V3, extracting the materials from the mixed liquid discharge port, entering the centrifugal extractor SE1 through the extractor feed port, carrying out centrifugal separation in the centrifugal extractor SE1, extracting the extractant phase from the upper part of the centrifugal extractor SE1 from the raffinate discharge port, and extracting the lean solvent from the lower part of the centrifugal extractor SE1 through the extraction lean oil discharge port.
Further, the absorption tower T1 adopts normal pressure or pressurization operation, the temperature of the tower kettle rich oil extracted by the absorption tower T1 into the rich oil storage tank V1 is not lower than 94 ℃, and the content of maleic anhydride in the tower kettle rich oil entering the rich oil storage tank V1 is not higher than 18.9% (wt).
Further, the three-strand rich oil materials extracted from the tower bottom material outlet of the absorption tower T1 are respectively sent to an absorbent circulating cooler E2, a rich oil storage tank V1 and a post flash tower circulating cooler E6, and the delivery distribution ratio of the three-strand rich oil materials is 0.6:0.15:0.25-0.8:0.05:0.15.
Further, the materials extracted from the rich oil extraction port are respectively pumped into a rich oil feed port of the desorption tower and a circulating cooler E6 of the post flash tower, and the distribution ratio of the materials is 0.4:0.6-0.8:0.2.
Further, materials extracted from a lean oil extraction port of a tower bottom of the post-flash tower T3 are respectively extracted to a post-flash tower preheater E5 and a lean oil storage tank V2, and the distribution ratio of the materials is 0.57:0.43-0.73:0.27.
Further, the materials extracted from the side extraction port of the post-flash tower are respectively extracted to a post-flash tower circulating cooler E6 and a rich oil storage tank V1, and the distribution ratio of the materials is 0.65:0.35-0.75:0.25.
Further, the materials extracted from the lean oil discharge port of the lean oil storage tank V1 are respectively extracted to the absorption tower T1, the tail gas recovery tower T4 and the extraction premixing tank V3, and the distribution ratio of the materials is 0.1:0.2:0.7-0.35:0.2:0.45.
Further, the desorption tower T2 and the post flash tower T3 are in decompression operation, the operation pressure is between-0.001 MPa and-0.010 MPa, the operation pressure of the post flash tower T3 is smaller than that of the desorption tower T2, three-stage steam ejectors are arranged in the desorption tower T2, and the tower kettle temperatures of the desorption tower T2 and the post flash tower T3 are not higher than 205 ℃.
Further, the absorbent is selected from one or a mixture of more than two of dimethyl phthalate, diethyl phthalate, dipropyl phthalate, diisopropyl phthalate, dibutyl phthalate, diisobutyl hexahydrophthalate and diethyl tetrahydrophthalate.
The beneficial effects of the present disclosure are:
(1) The maleic anhydride recovery process adopts novel solvents to absorb and desorb and purify maleic anhydride, three branches are arranged at the extraction port of a circulating pump P1 at the tower bottom of an absorption tower, one branch effectively ensures that the part of rich oil at the tower bottom of the absorption tower T1 is cooled and circulated and returned to the absorption tower T1 to further absorb maleic anhydride in the reaction gas, meanwhile, the extracted material at the tower bottom of the absorption tower T1 is divided into two materials, the extracted material from the side extraction port of a post flash tower and the extracted material are partially returned to a rich oil storage tank V1, and the extracted material is blended with the rich oil at the tower bottom of the absorption tower T1 through flow regulation, so that the content of maleic anhydride in the rich oil entering a desorption tower T2 is effectively ensured, the temperature of the tower bottom of the desorption tower T2 is lower than 210 ℃, the stability of the absorbent and the maleic anhydride is ensured, the production of industrial waste residues is reduced, and the equipment loss caused by the low operation pressure of the desorption tower T2 can be avoided.
(2) The two branches are arranged on the post-flash tower kettle pump P2, a large amount of produced materials at the tower kettle lean oil production outlet of the post-flash tower T3 are mixed with the produced materials at the tower kettle material production outlet of the desorption tower and then enter the post-flash tower T3 for further desorption, the heat of the produced materials of the post-flash tower T3 is fully utilized, the consumption of external steam of the post-flash tower preheater E5 is reduced, in addition, the tower kettle materials of the post-flash tower T3 are returned to the post-flash tower T3, the rising steam quantity is provided for the tower kettle of the post-flash tower T3, and the stable operation of the device is ensured.
(3) Three branch extraction buckles are arranged at the lean oil discharge port of the lean oil storage tank V2, so that on one hand, the stable operation of the absorption tower T1 and the tail gas recovery tower T4 is ensured, and on the other hand, impurities contained in the lean solvent are timely removed from the system, and the maleic anhydride absorption effect of the absorbent in long-term operation is ensured.
(4) The invention realizes the recycling of maleic anhydride and solvent in reaction gas, and has the advantages of good effect, high maleic anhydride yield, high solvent recycling rate, long-term stable operation of the device and remarkable environmental protection effect.
Drawings
FIG. 1 is a schematic view of the structure of the device of the present disclosure;
In the figure, a T1-absorption tower, a T2-desorption tower, a T3-post flash tower, a T4-tail gas recovery tower, an E1-reaction gas cooler, an E2-absorption tower circulating cooler, an E3-desorption tower condenser, an E4-desorption tower reboiler, an E5-post flash tower preheater, an E6-post flash tower circulating cooler, an E7-lean solvent cooler, a P1-absorption tower bottom circulating pump, a P2-post flash tower bottom pump, a P3-post flash tower circulating cooling pump, a V1-rich oil storage tank, a V2-lean oil storage tank, a V3-extraction premixing tank and an SE 1-centrifugal extractor;
1-waste gas discharge port, 2-lean solvent feed port, 3-absorbent circulating cooling material feed port, 4-reactor outlet mixed gas feed port, 5-tower kettle material outlet, 6-steam extraction port, 7-return port, 8-qualified maleic anhydride product extraction port, 9-desorption tower rich oil feed port, 10-desorption tower kettle steam feed port, 11-desorption tower kettle material extraction port, 12-gas phase extraction port, 13-post flash tower circulating cooling material feed port, 14-post flash tower feed port, 15-post flash tower side extraction port, 16-tower kettle lean oil extraction port, 17-waste gas extraction port, 18-tail gas recovery tower lean oil feed port, 19-tail gas recovery tower gas phase feed port, 20-tail gas recovery tower kettle material extraction port, 21-extractor feed port, 22-raffinate discharge port, 23-extraction lean oil discharge port, 24-absorption tower rich oil feed port, 25-post flash tower side extraction port, 26-rich oil feed port, 27-lean oil extraction port, 28-lean oil extraction port, 29-lean oil extraction port, 32-lean oil extraction port, and 32-mixed liquid feed port.
Detailed Description
The technical scheme of the present disclosure will be described in detail below with reference to the accompanying drawings.
In the description of the present disclosure, it should be understood that the terms "top," "bottom," "left," "right," "left above," "left below," "right above," "right below," "middle lower," "side," and the like indicate orientations or positional relationships based on the orientation or positional relationships shown in the drawings, are merely for convenience in describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. The terms "inner" and "outer" refer to the inner and outer sides with respect to the outline of each component itself.
The device for recycling maleic anhydride by using high-efficiency solvent is shown in fig. 1, and comprises an absorption tower T1, a desorption tower T2, a post flash tower T3, a tail gas recycling tower T4, an extractor SE1, a reaction gas cooler E1, an absorbent circulating cooler E2, a desorption tower condenser E3, a desorption tower reboiler E4, a post flash tower preheater E5, a post flash tower circulating cooler E6, a lean solvent cooler E7, an absorption tower kettle circulating pump P1, a post flash tower kettle pump P2, a post flash tower circulating cooling pump P3, a rich oil storage tank V1, a lean oil storage tank V2 and an extraction premixing tank V3.
The reaction gas cooler E1, the absorbent circulating cooler E2, the desorption tower condenser E3, the desorption tower reboiler E4, the post flash tower preheater E5, the post flash tower circulating cooler E6, the lean solvent cooler E7, the absorption tower kettle circulating pump P1, the post flash tower kettle pump P2 and the post flash tower circulating cooling pump P3 all comprise a feed inlet and a discharge outlet.
The top of the absorption tower T1 is provided with an exhaust gas discharge port 1, the upper right side is provided with a lean solvent feed port 2, the lower right side is provided with an absorbent circulating cooling material feed port 3, the left side is provided with a reactor outlet mixed gas feed port 4, and the bottom is provided with a tower kettle material outlet 5. The top of the desorption tower T2 is provided with a steam extraction port 6, the upper right side is provided with a return port 7, the upper left side is provided with a qualified maleic anhydride product extraction port 8, the lower left side is provided with a desorption tower rich oil feed port 9, the lower right side is provided with a desorption tower kettle steam feed port 10, and the bottom is provided with a desorption tower kettle material extraction port 11.
The top of the rear flash tower T3 is provided with a gas phase extraction port 12, the upper right side is provided with a rear flash tower circulating cooling material feed port 13, the left side is provided with a rear flash tower feed port 14, the lower right side is provided with a rear flash tower side line extraction port 15, and the bottom is provided with a tower kettle lean oil extraction port 16. The top of the tail gas recovery tower T4 is provided with a waste gas extraction port 17, the right side is provided with a lean oil feed port 18 of the tail gas recovery tower, the left side is provided with a gas phase feed port 19 of the tail gas recovery tower, and the bottom is provided with a material extraction port 20 of the tower kettle of the tail gas recovery tower.
The right side of the extractor SE1 is provided with an extractor feed inlet 21, the left side is provided with a raffinate discharge outlet 22, and the bottom is provided with an extraction lean oil discharge outlet 23. The left side of the rich oil storage tank V1 is provided with a rich oil feed inlet 24 for extracting rich oil from the tower bottom of the absorption tower, the bottom is provided with a rich oil feed inlet 25 for extracting rich oil from the side line of the post flash tower, and the right side is provided with a rich oil extraction outlet 26. The lean oil storage tank V2 is provided with a lean oil feed port 27 on the left side, an absorbent replenishing feed port 28 on the top, and a lean oil discharge port 29 on the right side. The upper left side of the extraction premixing tank V3 is provided with a premixing tank lean oil feed inlet 30, the lower left side is provided with an extractant feed inlet 31, and the bottom is provided with a mixed liquid discharge outlet 32.
The lean solvent feed inlet 2 is connected with the lean oil discharge outlet 29 and the extraction lean oil discharge outlet 23, the absorbent circulating cooling material feed inlet 3 is connected with the discharge outlet of the absorbent circulating cooler E2 and the material extraction outlet 20 of the tail gas recovery tower kettle, the reactor outlet mixed gas feed inlet 4 is connected with the discharge outlet of the reaction gas cooler E1, the tower kettle material outlet 5 is connected with the feed inlet of the absorption tower circulating pump P1, and the discharge outlet of the absorption tower circulating pump P1 is connected with the feed inlet of the absorbent circulating cooler E2, the rich oil feed inlet 24 of the absorption tower kettle and the feed inlet of the post flash tower circulating cooler E6.
The steam extraction port 6 is connected with a feed port of a desorption tower condenser E3, the desorption tower rich oil feed port 9 is connected with a rich oil extraction port 26, the desorption tower kettle steam feed port 10 is connected with a discharge port of a desorption tower reboiler E4, a desorption tower kettle material extraction port 11 is connected with a feed port of the desorption tower reboiler E4 and a feed port of a post flash tower preheater E5, and a discharge port of the desorption tower condenser E3 is connected with a reflux port 7 and a tail gas recovery tower gas phase feed port 19.
The gas phase extraction port 12 is connected with a gas phase feed port 19 of the tail gas recovery tower, the post-flash tower circulating cooling material feed port 13 is connected with a discharge port of a post-flash tower circulating cooler E6, the post-flash tower feed port 14 is connected with a discharge port of a post-flash tower preheater E5, a post-flash tower side line extraction port 15 is connected with a feed port of a post-flash tower circulating cooling pump P3, a tower kettle lean oil extraction port 16 is connected with a feed port of a post-flash tower kettle pump P2, a discharge port of the post-flash tower kettle pump P2 is connected with a feed port of the post-flash tower preheater E5 and a feed port of a lean solvent cooler E7, and a discharge port of the post-flash tower circulating cooling pump P3 is connected with a feed port of the post-flash tower circulating cooler E6 and a post-flash tower side line extraction rich oil feed port 25.
The lean oil feed inlet 18 of the tail gas recovery tower is connected with the lean oil discharge outlet 29, the feed inlet 21 of the extractor is connected with the mixed liquor discharge outlet 32, the lean oil feed inlet 27 is connected with the discharge outlet of the lean solvent cooler E7, and the lean oil discharge outlet 29 is connected with the lean oil feed inlet 18 of the tail gas recovery tower, the lean solvent feed inlet 2 and the lean oil feed inlet 30 of the premixing tank.
Embodiment one:
Referring to fig. 1, the process for recovering maleic anhydride from maleic anhydride reaction gas by using the above device comprises the following specific steps:
(1) The feed amount is 321900 kg/h, the feed composition is 5.50% (wt) of water, 1.22% of carbon monoxide, 73.55% of nitrogen, 15.09% of oxygen, 1.47% of carbon dioxide, 0.60% of n-butane, 0.05% of acetic acid, 0.04% of acrylic acid and 2.39% of maleic anhydride, the mixture is cooled to 115 ℃ by a reaction gas cooler E1, the mixture enters a 13 th tray of an absorption tower T1 from a reactor outlet mixture feed inlet 4, the feed temperature is 55 ℃, the feed amount is 41200 kg/h, the feed composition is 0.58% (wt) of water, 0.04% of maleic anhydride, 0.06% of maleic acid, 0.06% of fumaric acid, 0.12% of phthalic anhydride, 97.65% of tar and 1.42% of lean solvent enters a1 st tray of the absorption tower T1 from a lean solvent feed inlet 2, the material output from the absorption tower 2 after being cooled is mixed with the material extracted from a material extraction outlet 20 of a tail gas recovery tower, and the material output from the absorption agent circulation cooling material feed inlet 3 enters the 7 th tray of the absorption tower T1. The operating pressure of the absorption tower T1 is 0.14MPa, maleic anhydride and a small amount of impurities are fully absorbed by an absorbent in the absorption tower T1, the rich oil containing 13.63% maleic anhydride at the tower bottom is extracted from the absorption tower circulating pump P1 through a tower bottom material outlet 5 at a flow rate of 149499 kg/h, and then three streams are respectively sent to an absorbent circulating cooler E2, a rich oil storage tank V1 and a post flash tower circulating cooler E6 at flow rates of 89699 kg/h, 22126/kg/h and 37674 kg/h, and the waste gas with 0.003% maleic anhydride content discharged from a waste gas discharge port 1 at the top of the absorption tower T1 is sent out of a boundary region for incineration.
(2) The rich oil from the material outlet 5 of the tower bottom is mixed with the material from the material inlet and rich oil storage tank V1 from the material outlet 15 of the side line of the post flash tower in the rich oil storage tank V1 and then is extracted by the rich oil extraction pump from the rich oil extraction outlet 26, the mixture is divided into two material flows through three-way regulation, one material flow enters the desorption tower T2 through the 13 th plate of the material outlet 9 of the desorption tower at the flow rate of 64272 kg/h for rectification, the operating pressure of the desorption tower T2 is 0.003MPa, the number of plates is 28, the light component is extracted from the steam extraction outlet 6 through the condensation at the flow rate of 184 kg/h at the tower top, the qualified maleic anhydride from the side line product extraction outlet 8 at the flow rate of 7550 kg/h is the qualified maleic anhydride with the maleic anhydride content of 99.97% on the 4 th plate of the desorption tower T2, the material extraction outlet 11 at the moment is the absorbent with the anhydride content of 1.2% and the dibutyl phthalate content of 97.3% at the flow rate of 149499 kg/h, and the temperature of the material outlet of the tower bottom is 196 ℃ of the desorption tower T2.
(3) The material extracted from the material extraction port 11 of the bottom of the desorption tower and the extraction of the lean oil extraction port 16 of the bottom of the post flash tower T3 are mixed together, then the mixture enters the post flash tower preheater E5 to be preheated to 215 ℃ and then enters the post flash tower T3 for further desorption, the operation pressure of the post flash tower T3 is 0.002MPa, the number of the tower plates is 6, the gas phase extraction port 12 of the top of the tower extracts light components at the flow rate of 365 kg/h, the side line extraction port 15 of the post flash tower at the position of the 5 th tower plate extracts the absorbent with the maleic anhydride content of 12.9% at the flow rate of 232855 kg/h, the mixture is separated into two streams through three-way adjustment, wherein one stream 174641 kg/h of the streams is cooled by the post flash tower circulating cooling pump P3 and then enters the post flash tower circulating cooler E6 after being mixed with the 53742kg/h flow rate of the absorption tower bottom circulating pump P1, the other stream is cooled by the post flash tower circulating cooler E6 to 90 ℃ and returns to the 1 st tower plate of the post flash tower T3, and the other stream 58214 kg/h of the absorbent is fed into the rich oil storage tank V1 from the side line extraction port 25 of the post flash tower. Lean solvent with dibutyl phthalate content of 97.9% is extracted from the tower bottom lean oil extraction port 16 at a flow rate of 172341kg/h, and is three-way regulated by a post-flash tower bottom pump P2 to be divided into two streams, wherein one stream enters the post-flash tower preheater E5 at a flow rate of 120639 kg/h, and the other stream enters the lean solvent cooler E7 at a flow rate of 51702 kg/h, and enters the lean oil storage tank V2 after being cooled by the lean solvent cooler E7.
(4) Fresh absorbent is replenished by absorbent replenishment feed 28 into lean storage tank V2 at a flow rate of 29kg/h and mixed with the input of lean solvent cooler E7, and regulated by valve train to divide into three streams, one stream entering absorber T1 from lean solvent feed 2 at a flow rate of 5179 kg/h, one stream entering tail gas recovery tower T4 from tail gas recovery tower lean feed 18 at a flow rate of 10389 kg/h, and one stream entering extraction premix tank V3 from premix tank lean feed 30 at a flow rate of 36221 kg/h.
(5) The extracted material of the steam extraction port 6 at the top of the desorption tower T2 and the extracted material of the gas phase extraction port 12 at the top of the post flash tower T3 are mixed and then enter the bottom of the tail gas recovery tower T4 through the gas phase feed port 19 of the tail gas recovery tower, the tail gas recovery tower T4 is filled with 3m structured packing, maleic anhydride in the gas phase feed at the bottom of the tail gas recovery tower T4 is further absorbed by dibutyl phthalate in the top feed, the solvent with maleic anhydride content of 4.1% is extracted from the material extraction port 20 at the bottom of the tail gas recovery tower at the flow rate of 10781 kg/h, and the tail gas of 116 kg/h is extracted from the waste gas extraction port 17 at the top of the tail gas recovery tower and is sent out of the boundary zone for incineration.
(6) The material input by the lean oil feed inlet 30 of the premixing tank and the desalted water of 8500 kg/h input by the extractant feed inlet 31 are mixed in the extraction premixing tank V3, and then enter the centrifugal extractor SE1 for centrifugal separation, the raffinate discharge outlet 22 extracts the extractant phase, the lean solvent treated by 36346 kg/h extracted by the lean oil discharge outlet 23 is used as a circulating absorbent, wherein the dibutyl phthalate content is 97.7%.
In summary, in the technological process of recovering maleic anhydride from the maleic anhydride reaction gas, the yield of maleic anhydride is 98%, the purity of maleic anhydride is 99.97%, and the recycling rate of dibutyl phthalate as an absorbent is 99.92%.
Embodiment two:
(1) The feed amount is 324625 kg/h, the feed composition is 5.45% (wt) of water, 1.21% of carbon monoxide, 72.93% of nitrogen, 14.96% of oxygen, 1.46% of carbon dioxide, 0.59% of normal butane, 0.05% of acetic acid, 0.04% of acrylic acid, 3.21% of maleic anhydride, and maleic anhydride reactor outlet mixed gas is cooled to 138 ℃ by a reaction gas cooler E1, the mixed gas enters a 30 th tray of an absorption tower T1 from a reactor outlet mixed gas feed inlet 4, the feed temperature is 58 ℃, the feed amount is 28442 kg/h, the feed composition is 0.58% (wt) of water, 0.04% of maleic anhydride, 0.06% of maleic acid, 0.06% of fumaric acid, 0.12% of phthalic anhydride, 77.65% of diethyl phthalate, and 1.42% of tar enter a1 st tray of the absorption tower T1 from a lean solvent feed inlet 2, the material output from the absorbent circulating cooler E2 is cooled and enters the 16 th tray of the absorption tower 1 from a material recovery tower feed inlet 3 after the material output from a tail gas recovery tower outlet 20 is mixed. The operating pressure of the absorption tower T1 is 0.15MPa, maleic anhydride and a small amount of impurities in the absorption tower T1 are fully absorbed by an absorbent, rich oil containing 23.32% maleic anhydride is extracted from the tower bottom through a tower bottom material outlet 5 to an absorption tower circulating pump P1 at a flow rate of 234397 kg/h, then three streams are respectively sent to an absorbent circulating cooler E2, a rich oil storage tank V1 and a post flash tower circulating cooler E6 at flow rates of 187617 kg/h,18752 kg/h and 28128 kg/h, and waste gas with 0.001% maleic anhydride content discharged from a waste gas discharge port 1 at the top of the absorption tower T1 is sent out of a boundary region to be burned.
(2) The rich oil from the material outlet 5 of the tower bottom is mixed with the material from the material inlet and rich oil storage tank V1 from the side line of the post flash tower at the side line of the 15 th side line of the side flash tower in the rich oil storage tank V1, and is separated into two material flows through a three-way regulation by a rich oil extraction pump of the rich oil extraction outlet 26, one material flow enters the desorption tower T2 through the material inlet 9 of the desorption tower at the 18 th plate of the desorption tower T2 at the flow rate of 520552 kg/h for rectification, the operating pressure of the desorption tower T2 is 0.003MPa, the number of plates is 35, the light component is extracted from the steam extraction outlet 6 through condensation at the top of the tower at the flow rate of 254 kg/h, the qualified maleic anhydride product extraction outlet 8 at the side line at the 5 th plate of the desorption tower T2 at the flow rate of 10230 kg/h for maleic anhydride content 99.92%, the material extraction outlet 11 at the flow rate of the desorption tower bottom at the flow rate of 41570 kg/h for maleic anhydride content 0.6%, the dibutyl phthalate content 62.35%, the diethyl phthalate content at the moment, and the temperature of the desorption tower T2 at the moment of the absorbent of the temperature of the tower is 34 DEG.2.
(3) The material extracted from the material extraction port 11 at the bottom of the desorption tower and the extraction of the lean oil extraction port 16 at the bottom of the post flash tower T3 are mixed together, then the mixture enters the post flash tower preheater E5 to be preheated to 215 ℃ and then enters the post flash tower T3 for further desorption, the operation pressure of the post flash tower T3 is 0.002MPa, the number of the tower plates is 4, the gas phase extraction port 12 at the top of the tower extracts light components at the flow rate of 494 kg/h, the absorbent with the maleic anhydride content of 19.8% is extracted from the side extraction port 15 at the side extraction port of the 3 rd tower at the flow rate of 310000 kg/h, the mixture is separated into two streams through three-way adjustment, wherein one stream 207700 kg/h of the streams is cooled by the post flash tower circulating cooling pump P3 and then enters the post flash tower circulating cooler E6 after being mixed with 97127 kg/h of the absorption tower circulating pump P1, the gas phase extraction port 12 is cooled to 90 ℃ by the post flash tower circulating cooler E6 and returns to the 1 st tower plate of the post flash tower T3, and the other stream 102300 kg/h of the absorbent enters the rich oil extraction port 25 from the side extraction port of the post flash tower to enter the storage tank V1. Lean solvent with dibutyl phthalate content of 76.99% and diethyl tetrahydrophthalate content of 19.74% is extracted from the tower bottom lean oil extraction port 16 at a flow rate of 132977 kg/h, is three-way regulated by a post-flash tower bottom pump P2 and is divided into two streams, one stream enters the post-flash tower preheater E5 at a flow rate of 97073 kg/h, and the other stream enters the lean solvent cooler E7 at a flow rate of 35904 kg/h, and is cooled by the lean solvent cooler E7 and then enters the lean oil storage tank V2.
(4) Fresh absorbent is replenished by absorbent replenishment feed 28 and mixed with the input of lean oil holding tank V2 and lean solvent cooler E7 at a flow rate of 28 kg/h, and then regulated by valve train to separate into three streams, one stream entering absorber T1 from lean solvent feed 2 at a flow rate of 10932 kg/h, one stream entering tail gas recovery tower T4 from tail gas recovery tower lean feed 18 at a flow rate of 7220 kg/h, and one stream entering extraction premix tank V3 from premix tank lean feed 30 at a flow rate of 17836 kg/h.
(5) The extracted material of the steam extraction port 6 at the top of the desorption tower T2 and the extracted material of the gas phase extraction port 12 at the top of the post flash tower T3 are mixed and then enter the bottom of the tail gas recovery tower T4 through the gas phase feed port 19 of the tail gas recovery tower, the tail gas recovery tower T4 is provided with 2.8 m structured packing, maleic anhydride in the gas phase feed at the bottom of the tail gas recovery tower T4 is further absorbed by dibutyl phthalate in the top feed, the solvent with maleic anhydride content of 6.4% is extracted from the material extraction port 20 at the bottom of the tail gas recovery tower at the flow rate of 7733 kg/h, and the tail gas with 234 kg/h is extracted from the waste gas extraction port 17 at the top of the tail gas recovery tower and is sent out of the boundary zone for incineration.
(6) The material input by the lean oil feed inlet 30 of the premixing tank and the desalted water 5452 kg/h input by the extractant feed inlet 31 are mixed in the extraction premixing tank V3 and then enter the centrifugal extractor SE1 for centrifugal separation, the raffinate discharge outlet 22 extracts the extractant phase, the lean solvent treated by the 17813 kg/h extracted by the lean oil discharge outlet 23 is used as a circulating absorbent, wherein the dibutyl phthalate content is 77% and the tetrahydrodiethyl phthalate content is 19.74%.
In summary, in the technological process of recovering maleic anhydride from the maleic anhydride reaction gas, the yield of maleic anhydride is 98.1%, the purity of maleic anhydride is 99.92%, and the recycling rate of the absorbent is 99.9%.
Embodiment III:
(1) The feed amount is 679678 kg/h, the feed composition is 1.74% (wt) of water, 1.57% of carbon monoxide, 75.0% of nitrogen, 15.79% of oxygen, 3.85% of carbon dioxide, 0.05% of normal butane and 1.95% of maleic anhydride, the mixed gas is cooled to 130 ℃ by a reaction gas cooler E1, the mixed gas enters a 22 nd tray of an absorption tower T1 from a reactor outlet mixed gas feed port 4, the feed temperature is 58 ℃, the feed amount is 60414 kg/h, the feed composition is 0.38% (wt) of water, 0.1% of maleic anhydride, 0.02% of maleic acid, 0.06% of fumaric acid, 0.2% of phthalic anhydride, 99.0% of dibutyl phthalate and 0.2% of tar are fed into a 1 st tray of the absorption tower T1 from a lean solvent feed port 2, the fed material is cooled by an absorbent circulation cooler E2 and fed into a 12 th tray of the absorption tower T1 from an absorbent circulation cooling material feed port 3 after being mixed with the material taken out from a tail gas recovery tower bottom material outlet 20. The operating pressure of the absorption tower T1 is 0.14MPa, maleic anhydride and a small amount of impurities in the absorption tower T1 are fully absorbed by an absorbent, rich oil containing 16.9% maleic anhydride at the flow rate of 350482 kg/h is extracted from the tower bottom through a tower bottom material outlet 5 to an absorption tower circulating pump P1, then three streams are respectively sent to an absorbent circulating cooler E2, a rich oil storage tank V1 and a post flash tower circulating cooler E6 at the flow rates of 260058 kg/h,33457 kg/h and 56967 kg/h, and waste gas with 0.001% maleic anhydride content discharged from a waste gas discharge port 1 at the top of the absorption tower T1 is sent out of a boundary region to be burned.
(2) The rich oil from the material outlet 5 of the tower bottom is mixed with the material from the material inlet and rich oil storage tank V1 from the material outlet 15 of the side line of the post flash tower in the rich oil storage tank V1 and then is extracted by the rich oil extraction pump from the rich oil outlet 26, the mixture is divided into two material flows through three-way regulation, one material flow enters the desorption tower T2 through the material inlet 9 of the rich oil of the desorption tower at the 20 th plate of the desorption tower T2 at the flow rate of 86078 kg/h for rectification, the operating pressure of the desorption tower T2 is 0.003MPa, the number of plates is 39, the light component is extracted from the steam outlet 6 at the flow rate of 11kg/h through condensation at the tower top, the qualified maleic anhydride product outlet 8 of the side line extracts the qualified maleic anhydride with the maleic anhydride content of 99.99% from the 4 th plate of the desorption tower T2 at the flow rate of 13100 kg/h, the material outlet 11 of the tower bottom at the moment extracts the absorbent with the maleic anhydride content of 72967 kg/h and the dibutyl phthalate content of 98.5%, and the temperature of the material outlet of the desorption tower T2 is 201℃.
(3) The material extracted from the material extraction port 11 of the bottom of the desorption tower and the extraction of the lean oil extraction port 16 of the bottom of the post flash tower T3 are mixed together and then enter the post flash tower preheater E5 to be preheated to 210 ℃ and then enter the post flash tower T3 for further desorption, the operation pressure of the post flash tower T3 is 0.002MPa, the number of the tower plates is 8, the gas phase extraction port 12 of the top of the tower extracts light components at the flow rate of 2062 kg/h, the side extraction port 15 of the post flash tower at the 6 th tower plate extracts the absorbent with the maleic anhydride content of 14.85% at the flow rate of 32000 kg/h, the absorbent is three-way regulated and divided into two streams, wherein one stream of the flow rate of 231360 kg/h is cooled by the post flash tower circulating cooling pump P3 and then enters the post flash tower circulating cooler E6 after being mixed with 92986 kg/h of the absorption tower bottom circulating pump P1, the gas phase extraction port 12 is cooled to 80 ℃ by the post flash tower circulating cooler E6 and then returns to the 1 st tower plate of the post flash tower T3, and the other stream of the flow rate of 88640 kg/h is fed into the rich oil storage tank V1 from the side extraction port of the post flash tower. Lean solvent with dibutyl phthalate content of 99.0% is extracted from the tower bottom lean oil extraction port 16 at a flow rate of 201745 kg/h, and is three-way regulated by a post-flash tower bottom pump P2 to be divided into two streams, wherein one stream enters the post-flash tower preheater E5 at a flow rate of 126494 kg/h, and the other stream enters the lean solvent cooler E7 at a flow rate of 75251 kg/h, and enters the lean oil storage tank V2 after being cooled by the lean solvent cooler E7.
(4) Fresh absorbent is replenished by absorbent replenishment feed 28 into lean storage tank V2 at a flow rate of 52 kg/h and mixed with the input of lean solvent cooler E7, and regulated by valve block to separate into three streams, one stream entering absorber T1 from lean solvent feed 2 at a flow rate of 22854 kg/h, one stream entering tail gas recovery tower T4 from tail gas recovery tower lean feed 18 at a flow rate of 25050 kg/h, and one stream entering extraction premix tank V3 from premix tank lean feed 30 at a flow rate of 27347 kg/h.
(5) The extracted material of the steam extraction port 6 at the top of the desorption tower T2 and the extracted material of the gas phase extraction port 12 at the top of the post flash tower T3 are mixed and then enter the bottom of the tail gas recovery tower T4 through the gas phase feed port 19 of the tail gas recovery tower, the tail gas recovery tower T4 is filled with 5 m structured packing, maleic anhydride in the gas phase feed at the bottom of the tail gas recovery tower T4 is further absorbed by dibutyl phthalate in the top feed, the solvent with the maleic anhydride content of 11.9% is extracted from the material extraction port 20 at the bottom of the tail gas recovery tower at the flow rate of 17065 kg/h, and the tail gas with the maleic anhydride content of 58.6 kg/h is extracted from the waste gas extraction port 17 at the top of the tail gas recovery tower and is sent out of the boundary zone for incineration.
(6) The material input by the lean oil feed inlet 30 of the premixing tank and 8000kg/h desalted water input by the extractant feed inlet 31 are mixed in the extraction premixing tank V3, and then enter the centrifugal extractor SE1 for centrifugal separation, the raffinate discharge port 22 extracts the extractant phase, and the lean solvent treated by 27346 kg/h extracted by the lean oil discharge port 23 is used as a circulating absorbent, wherein the dibutyl phthalate content is 99.2%.
In summary, in the technological process of recovering maleic anhydride from the maleic anhydride reaction gas, the yield of maleic anhydride is 98.9%, the purity of maleic anhydride is 99.99%, and the recycling rate of dibutyl phthalate as an absorbent is 99.91%.
As described above, although the present invention has been shown and described with reference to certain preferred embodiments, it is not to be construed as limiting the invention itself. Various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.
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