Vinyl chloride monomer recovery process
A vinyl chloride monomer and vinyl chloride technology, which is applied in the disproportionation separation/purification of halogenated hydrocarbons, organic chemistry, etc., can solve the problems of reduced quality of polymer products, large fluctuations in size, and rising costs, so as to improve quality and reduce usage. amount of effect
Active Publication Date: 2018-12-04
TIANJIN PULAI CHEM TECH
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Problems solved by technology
[0007] It can be seen that at this stage, technical problems such as impurity removal and purification of gases not involved in the polymerization reaction in the production of vinyl chloride are still difficult to be effectively solved. This part of the gas-phase monomer carries a large amount of unknown additives and contains methyl chloride, ethyl chloride, ethyl chloride, etc. Impurities that are not easy to remove, such as aldehyde, return to the polymerization raw material with the gas phase monomer during the compression and condensation process after polymerization, which interferes with the polymerization reaction again, accumulates in the system continuously, and deteriorates the progress of the polymerization reaction. Moreover, this part The gas volume is very unstable (the instantaneous gas volume fluctuates greatly), which is also an aspect that makes removal difficult
At present, most factories can only increase the input of additives such as initiators to ensure the normal progress of the polymerization reaction, but this method will not only bring about the consequences of increased costs and lower quality of polymerization products, but also cannot solve the problem of additives in the system. problems accumulated in
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Embodiment 1
[0039]A recovery process for vinyl chloride monomers, the raw materials and residual additives that have not participated in the polymerization reaction after the raw material vinyl chloride is polymerized in a polymerization tank are processed under the conditions of 38-42 ° C and a pressure of about 0.23 MPa (0.2-0.3 MPa is the same Achievable), through the alkali washing tower in the form of gas, and carry out alkali washing under the condition of 39°C-44°C and about 0.2MPa (0.18-0.3MPa can be realized), and the alkali wash solution is 10-20% NaOH solution , During the alkaline cleaning process, acetaldehyde can be completely removed, ethyl chloride, methyl chloride and additives can be partially removed. The alkali washing tower is 20-40 layers of ctst three-dimensional mass transfer trays. The recovered gas enters the alkali washing tower from the lower part of the alkali washing tower in the gas phase, and the alkali washing liquid enters the alkali washing tower from the...
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The invention provides a vinyl chloride monomer recovery technology. The technology comprises the following steps: carrying out a polymerization reaction on a vinyl chloride raw material to generate polyvinyl chloride, carrying out alkali washing technology treatment on the unreacted gaseous vinyl chloride monomer, condensing the impurity removed vinyl chloride monomer, and rectifying the condensed vinyl chloride monomer to complete recovery of the vinyl chloride monomer. The purity of the vinyl chloride monomer recovered through the recovery technology is very high, and the recovered vinyl chloride monomer undergoes the polymerization reaction as a raw material to greatly improve the quality of a polymerized product and reduce the dosage of parts of assistants.
Description
technical field [0001] The invention relates to the field of polyvinyl chloride production, in particular to the recovery process of vinyl chloride monomer. Background technique [0002] At this stage, in the production process of PVC, the general process flow of each vinyl chloride manufacturer in the recovery section is as follows: after the vinyl chloride raw material undergoes polymerization reaction to produce polyvinyl chloride, the unreacted vinyl chloride gaseous monomer is compressed and condensed And then put it into the polymerization production as the polymerization raw material. [0003] The recycling process of this vinyl chloride monomer has the following disadvantages in actual production: [0004] (1) A large number of initiators, dispersants, polymerization inhibitors, defoamers, anti-sticking agents and other additives are used in the polymerization process, such as: diethylhexyl peroxydicarbonate, iso-neodecanoate peroxide Propylbenzene, tert-butyl pero...
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IPC IPC(8): C07C17/38C07C21/06
CPCC07C17/38C07C21/06
Inventor 王福宽王伟张昌伟邱剑锋轩烨张文林
Owner TIANJIN PULAI CHEM TECH