CN101348446A - Phosgene removing method for TDI production - Google Patents
Phosgene removing method for TDI production Download PDFInfo
- Publication number
- CN101348446A CN101348446A CNA2008100181177A CN200810018117A CN101348446A CN 101348446 A CN101348446 A CN 101348446A CN A2008100181177 A CNA2008100181177 A CN A2008100181177A CN 200810018117 A CN200810018117 A CN 200810018117A CN 101348446 A CN101348446 A CN 101348446A
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- China
- Prior art keywords
- phosgene
- tower
- pressure
- tdi
- low pressure
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- YGYAWVDWMABLBF-UHFFFAOYSA-N Phosgene Chemical compound ClC(Cl)=O YGYAWVDWMABLBF-UHFFFAOYSA-N 0.000 title claims abstract description 145
- 238000000034 method Methods 0.000 title claims abstract description 23
- 238000004519 manufacturing process Methods 0.000 title claims abstract description 6
- 239000000463 material Substances 0.000 claims abstract description 11
- 239000002904 solvent Substances 0.000 claims abstract description 8
- 238000011084 recovery Methods 0.000 claims description 16
- 238000006243 chemical reaction Methods 0.000 claims description 9
- VNGOYPQMJFJDLV-UHFFFAOYSA-N dimethyl benzene-1,3-dicarboxylate Chemical compound COC(=O)C1=CC=CC(C(=O)OC)=C1 VNGOYPQMJFJDLV-UHFFFAOYSA-N 0.000 claims description 7
- 238000001816 cooling Methods 0.000 claims description 4
- 230000003287 optical effect Effects 0.000 claims description 4
- 239000007788 liquid Substances 0.000 abstract description 2
- 239000000203 mixture Substances 0.000 abstract description 2
- 239000012295 chemical reaction liquid Substances 0.000 abstract 4
- JLVWYWVLMFVCDI-UHFFFAOYSA-N diethyl benzene-1,3-dicarboxylate Chemical compound CCOC(=O)C1=CC=CC(C(=O)OCC)=C1 JLVWYWVLMFVCDI-UHFFFAOYSA-N 0.000 abstract 1
- 239000012467 final product Substances 0.000 abstract 1
- 231100000614 poison Toxicity 0.000 abstract 1
- 230000007096 poisonous effect Effects 0.000 abstract 1
- DVKJHBMWWAPEIU-UHFFFAOYSA-N toluene 2,4-diisocyanate Chemical compound CC1=CC=C(N=C=O)C=C1N=C=O DVKJHBMWWAPEIU-UHFFFAOYSA-N 0.000 description 22
- 239000000047 product Substances 0.000 description 11
- 241000282326 Felis catus Species 0.000 description 5
- 239000007789 gas Substances 0.000 description 4
- 238000010586 diagram Methods 0.000 description 2
- 238000007599 discharging Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000012442 inert solvent Substances 0.000 description 2
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 238000007033 dehydrochlorination reaction Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000007701 flash-distillation Methods 0.000 description 1
- 229910000041 hydrogen chloride Inorganic materials 0.000 description 1
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 description 1
- 238000009776 industrial production Methods 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 239000000758 substrate Substances 0.000 description 1
- VOZKAJLKRJDJLL-UHFFFAOYSA-N tolylenediamine group Chemical group CC1=C(C=C(C=C1)N)N VOZKAJLKRJDJLL-UHFFFAOYSA-N 0.000 description 1
- 231100000167 toxic agent Toxicity 0.000 description 1
- 239000002341 toxic gas Substances 0.000 description 1
- 239000003440 toxic substance Substances 0.000 description 1
- 239000002699 waste material Substances 0.000 description 1
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- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
A phosgene removal method used for manufacturing TDI relates to a method for removing poisonous gas from a gas-liquid mixture. The method comprises the following steps that a reaction liquid which contains TDI, a solvent isophthalic acid diethylester and superfluous phosgene and is discharged from a phosgenation reactor undergoes high-pressure phosgene removal treatment at first and then undergoes low-pressure phosgene removal treatment; moreover, the reaction liquid is reheated during low-pressure phosgene removal treatment so as to reboil the phosgene; then, the reaction liquid enters a negative-pressure phosgene removal stage so as to remove the phosgene in the material through negative-pressure phosgene removal treatment; and finally, final product TDI can be obtained after the reaction liquid is treated by a residue removal tower and a solvent removal tower.
Description
Technical field
The present invention relates to from gas-liquid mixture, remove the method for toxic gas.
Background technology
The production of industrial TDI (tolylene diisocyanate) all adopts tolylene diamine to carry out phosgenation reaction with excess phosgene in inert solvent, reaction generates target product TDI and byproduct hydrogenchloride, pass through dehydrochlorination again, take off phosgene, take off steps such as residue and desolventizing, finally obtain product TDI, phosgene and inert solvent excessive in the reaction process recycle after reclaiming.Phosgene as one of reactant is a kind of highly toxic substance, must remove fully from product to guarantee the security of product TDI.Removing of phosgene generally taken off the phosgene tower through high pressure, low pressure and negative pressure and removed flow process for three grades in the TDI industrial production, to guarantee not contain phosgene in the product.The reaction solution that comes out from phosgenation reactor contains product TDI, solvent dimethyl isophthalate (DEIP) and excessive phosgene, take off the phosgene tower through high pressure-off phosgene tower, low pressure-off phosgene tower and negative pressure successively and remove phosgene in the material, obtain the finished product TDI through after taking off residue tower and desolventizing tower again.Its mesohigh takes off the phosgene tower and removes most of phosgene, and the phosgene that the removes gas tank that directly delusters after further cooling recycles; The phosgene that low pressure-off phosgene tower removes recycles after sending the phosgene recovery system to purify again; Negative pressure is taken off the phosgene that the phosgene tower removes and is also sent into the phosgene recovery system with vacuum system.
Traditional removes in the phosgene flow process, the heat that low pressure-off phosgene tower relies on material to provide from the flash distillation of high pressure-off phosgene Tata substrate material is realized phosgene removing under low pressure, when high pressure-off phosgene tower operational anomaly, the regulating measure that low pressure-off phosgene tower there is no need is remedied, take off the phosgene tower but problem is directly passed to negative pressure, cause negative pressure to take off phosgene tower vacuum system instability; In addition, heavy constituent such as TDI go vacuum system can form waste, still contain phosgene in the bottoms material, influence follow-up normal running of taking off residue, desolventizing system, when the phosgene that removes when low pressure-off phosgene tower send the phosgene recovery system, cause phosgene recovery system load bigger.Low pressure-off phosgene tower is to operate under the pressure of 0.17MPa, needs pressure-controlling on the one hand, has increased the complicacy of operation; On the other hand since TDI at high temperature easily polymerization generate residue, so, need the control column bottom temperature below 170 ℃, and under this temperature, also contain more phosgene in the bottoms material, make the removal effect of the finished product TDI phosgene not good.
Summary of the invention
The purpose of this invention is to provide the phosgene removing method that a kind of TDI of being used for produces, in the load that reduces the phosgene recovery system, improve the turndown ratio of system.
The present invention is used for the phosgene removing method that TDI produces, the reaction solution that contains TDI, solvent dimethyl isophthalate and excessive phosgene that comes out from phosgenation reactor at first carries out high pressure-off phosgene to be handled, and then hang down the pressure-off phosgene and handle, carry out reheat in the low pressure-off optical processing stage, the phosgene of low pressure-off photophase is seethed with excitement again, enter negative pressure then and take off the phosgene stage, take off optical processing through negative pressure and remove phosgene in the material, obtain the finished product TDI through after taking off residue tower and desolventizing tower again.
Usefulness of the present invention is: by after will hanging down pressure-off phosgene tower and changing atmospheric operation into, make the easy to control of tower; After low pressure-off phosgene tower increased a tower bottom reboiler, make that on the one hand easier control is formed in discharging at the bottom of cat head discharging and the tower, can guarantee that cat head phosgene purity reaches the requirement that can recycle, avoided sending the phosgene recovery system again with the cat head phosgene, the load of phosgene recovery system reduces greatly, on the other hand, increased the turndown ratio of whole flow process, when high pressure-off phosgene tower fluctuation of service, can keep stablizing the effect that follow-up negative pressure is taken off the operation of phosgene tower by adjusting low pressure-off phosgene tower, the turndown ratio that increases flow process makes flow process more stable.
The present invention makes cat head phosgene purity reach the requirement that can be recycled, avoided sending the phosgene recovery system again with the cat head phosgene, the phosgene amount of the feasible gas recovery system of delustering is reduced to 54kg/h, the load of phosgene recovery system has reduced by 79.93%, and improved the turndown ratio of whole flow process, made flow process more stable.
Description of drawings
Fig. 1 is the production system synoptic diagram of the method for prior art enforcement phosgene removing, and Fig. 2 is for implementing the production system synoptic diagram of the inventive method.Identically among Reference numeral among Fig. 1 and Fig. 2 all be expressed as same device.
Embodiment
Embodiment 1:
As shown in Figure 2, the present invention is used for the phosgene removing method that TDI produces, by means of a high pressure-off phosgene tower 1, a phosgene jar 2 that communicates with high pressure-off phosgene tower 1, a low pressure-off phosgene tower 3, a negative pressure is taken off phosgene tower 4 and is carried out removing of phosgene, the steps include: from what phosgenation reactor came out to contain TDI, the reaction solution of solvent dimethyl isophthalate and excessive phosgene at first carries out high pressure-off phosgene through high pressure-off phosgene tower 1 to be handled, enter low pressure-off phosgene tower 3 then and hang down the processing of pressure-off phosgene, heat in low pressure-off phosgene tower 3 bottoms, phosgene in the low pressure-off phosgene tower 3 is seethed with excitement again, enter negative pressure then and take off phosgene tower 4, take off phosgene tower 4 through negative pressure and remove phosgene in the material, obtain the finished product TDI through after taking off residue tower and desolventizing tower again.Its mesohigh takes off phosgene tower 1 and removes most of phosgene, and the phosgene that the removes gas tank 2 that directly delusters after further cooling recycles; The phosgene that low pressure-off phosgene tower 3 removes recycles after sending the phosgene recovery system to purify again; Negative pressure is taken off the phosgene that phosgene tower 4 removes and is also sent into the phosgene recovery system with vacuum system 5.
Embodiment 2:
As shown in Figure 2, the present invention is used for the phosgene removing method that TDI produces, the steps include: at first to handle through high pressure-off phosgene tower 1 from the reaction solution that contains TDI, solvent dimethyl isophthalate and excessive phosgene that phosgenation reactor comes out, entering the low pressure-off phosgene tower 3 of being furnished with tower bottom reboiler 6 then heats, enter negative pressure then and take off phosgene tower 4, take off phosgene tower 4 through negative pressure and remove phosgene in the material, obtain the finished product TDI through after taking off residue tower and desolventizing tower again.Its mesohigh takes off phosgene tower 1 and removes most of phosgene, and the phosgene that the removes gas tank 2 that directly delusters after further cooling recycles; The phosgene that low pressure-off phosgene tower 3 removes recycles after sending the phosgene recovery system to purify again; Negative pressure is taken off the phosgene that phosgene tower 4 removes and is also sent into the phosgene recovery system with vacuum system 5.
Claims (4)
1, is used for the phosgene removing method that TDI produces, it is characterized in that at first carrying out high pressure-off phosgene from the reaction solution that contains TDI, solvent dimethyl isophthalate and excessive phosgene that phosgenation reactor comes out handles, and then hang down the pressure-off phosgene and handle, carry out reheat in the low pressure-off optical processing stage, the phosgene of low pressure-off photophase is seethed with excitement again, enter negative pressure then and take off the phosgene stage, take off optical processing through negative pressure and remove phosgene in the material, obtain the finished product TDI through after taking off residue tower and desolventizing tower again.
2, be used for the phosgene removing method that TDI produces, it is characterized in that from what phosgenation reactor came out containing TDI, the reaction solution of solvent dimethyl isophthalate and excessive phosgene at first passes through high pressure-off phosgene tower (1) to carry out high pressure-off phosgene and handles, the low pressure-off phosgene tower (3) that enters then hangs down the pressure-off phosgene to be handled, heat by the tower bottom reboiler (6) that is installed in low pressure-off phosgene tower (3) bottom, phosgene is seethed with excitement again, enter negative pressure then and take off phosgene tower (4), take off phosgene tower (4) through negative pressure and remove phosgene in the material, obtain the finished product TDI through after taking off residue tower and desolventizing tower again.
3, according to claim 1ly be used for the phosgene removing method that TDI produces, it is characterized in that high pressure-off phosgene tower (1) removes most of phosgene gas tank (2) that directly delusters and recycles after further cooling off; The phosgene that low pressure-off phosgene tower (3) removes recycles after sending the phosgene recovery system to purify again; Negative pressure is taken off the phosgene that phosgene tower (4) removes and is also sent into the phosgene recovery system with vacuum system (5).
4,, it is characterized in that low pressure-off phosgene tower (3) takes off the phosgene tower for normal pressure according to claims 1 described phosgene removing method that is used for TDI production.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2008100181177A CN101348446A (en) | 2008-04-25 | 2008-04-25 | Phosgene removing method for TDI production |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA2008100181177A CN101348446A (en) | 2008-04-25 | 2008-04-25 | Phosgene removing method for TDI production |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101348446A true CN101348446A (en) | 2009-01-21 |
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Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA2008100181177A Pending CN101348446A (en) | 2008-04-25 | 2008-04-25 | Phosgene removing method for TDI production |
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| Country | Link |
|---|---|
| CN (1) | CN101348446A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102258935A (en) * | 2011-04-22 | 2011-11-30 | 顾伟文 | Recovery and utilization method of phosgene in phosgenation reaction tail gas |
| CN101717335B (en) * | 2009-12-10 | 2012-10-31 | 甘肃银达化工有限公司 | A kind of method that reclaims DEIP in TDI residue |
| CN101698652B (en) * | 2009-11-05 | 2012-12-26 | 甘肃银达化工有限公司 | Method for purifying cyclic solvent in producing TDI |
| CN105384633A (en) * | 2015-12-14 | 2016-03-09 | 青岛科技大学 | Continuous removal method of heavy solvent method TDI residues |
| WO2016109987A1 (en) * | 2015-01-07 | 2016-07-14 | 万华化学集团股份有限公司 | Method for replacement of phosgene synthesis column catalyst |
-
2008
- 2008-04-25 CN CNA2008100181177A patent/CN101348446A/en active Pending
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101698652B (en) * | 2009-11-05 | 2012-12-26 | 甘肃银达化工有限公司 | Method for purifying cyclic solvent in producing TDI |
| CN101717335B (en) * | 2009-12-10 | 2012-10-31 | 甘肃银达化工有限公司 | A kind of method that reclaims DEIP in TDI residue |
| CN102258935A (en) * | 2011-04-22 | 2011-11-30 | 顾伟文 | Recovery and utilization method of phosgene in phosgenation reaction tail gas |
| WO2016109987A1 (en) * | 2015-01-07 | 2016-07-14 | 万华化学集团股份有限公司 | Method for replacement of phosgene synthesis column catalyst |
| US10046289B2 (en) | 2015-01-07 | 2018-08-14 | Wanhua Chemical Group Co., Ltd. | Method for replacement of phosgene synthesis column catalyst |
| CN105384633A (en) * | 2015-12-14 | 2016-03-09 | 青岛科技大学 | Continuous removal method of heavy solvent method TDI residues |
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| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C02 | Deemed withdrawal of patent application after publication (patent law 2001) | ||
| WD01 | Invention patent application deemed withdrawn after publication |
Open date: 20090121 |