Production method of polyvinyl chloride with small pot suspension method

Abstract

The invention relates to a polyvinyl chloride, in particular to a production method of the polyvinyl chloride with a small pot suspension method, belonging to the technical field of chemical industry, characterized in that: EHP (peroxydicarbonate-diethylhexyl ester) which has high activity, uniform heat generation, and light sticking is used, based on using the EHP, a composite initiator is used, heat exchange capability of the kettle is fully utilized to allow the reaction speed to be uniform, prevent the acceleration of the post reaction speed to guarantee the timely removal of polymerization heat, and reduce the polymerization time; a composite system of binary PVA (polyvinyl alcohol) with different alcoholysis degrees and a polybasic composite system of HPMC (hydroxypropyl methyl cellulose) and PVA are used; and a secondary water injection technology is used, so that viscosity of the materials is reduced, the heat removing capability of the polymerizing pot is improved, and the quality of the PVC products is increased. According to the invention, the polymerization time is reduced, the viscosity of the materials is reduced, the cleaning time of the polymerizing pot, and a low water-oil ratio can be used for filling, so that the production capacity is improved.

Description

technical field [0001] The invention relates to a polyvinyl chloride, in particular to a production method of polyvinyl chloride by a suspension method in a small kettle, and belongs to the technical field of chemical industry. Background technique [0002] In the chemical industry, it is generally considered a small kettle below 30m, and a large kettle above 70m. Large single kettles have high output, low energy consumption, advanced supporting technology, good product quality and high stability. DSC control systems are widely used, and safety protection measures are perfect. They have inherent advantages that small kettles cannot match. It is the general trend to replace small kettles. However, large-scale kettles also have a large amount of investment capital, and technology-intensive requirements for personnel are high, which can solve problems such as a small number of employees. At present, there are still quite a few small kettles in my country's PVC production field...

AI Technical Summary

Problems solved by technology

The problems and solutions of different small kettles are not the same. Firstly, the production capacity is low and the energy consumption is large. To increase the production, we can increase the output of a single kettle and the number of reactors per unit time (shorten the reaction and reaction auxiliary time). The reason for this result is that the product quality is poor and unstable. The reasons include poor heat removal ability of small kettles, high viscosity in the later stage of the reaction system, and excessive heat release. It is mainly solved by equipment transformation and uniform heat release process to reduce viscosity.

The second is safety and environmental protection issues. PVC polymerized monomer vinyl chloride (VCM) is flammable and explosive and has strong carcinogenic effect. The production automation of small kettles is low, the process is backward, the opening operation and the recovery of unreacted VCM are not complete, mainly relying on process improvement ( Closed feeding, enhanced VCM recovery) solution