Technology for producing polymeric material polyvinyl chloride from crude vinyl chloride

Abstract

The invention discloses a technology for producing polymeric material polyvinyl chloride from crude vinyl chloride. The technology comprises a crude product preparation process, a purifying process and a polymerization process, and hot water discharged from the shell of a converter in the crude product preparation process undergoes heat exchange through a heat exchanger, then enters the upper portion of a steam absorption tower, absorbs heat evaporated by a hot water tank in the converter, and automatically flows into the hot water tank of the converter as a heat source for assisting a reaction in the converter; a compression device of crude vinyl chloride gas in the purifying process selects a screw compressor; and cold desalinized water in the polymerization process undergoes heat exchange in the heat exchanger in the crude product preparation process to prepare hot desalinized water used for polymerization, and a cooling medium of a polymerization kettle comprises circulating water and 7 DEG C refrigerated water. The technology has the advantages of simple and reasonable design, effective utilization of the vinyl chloride conversion heat, energy saving and consumption reduction, realization of high automation degree and low energy consumption due to the compression device selecting the screw compressor, and realization of the shortening of the polymerization reaction time of the polymerization kettle, output improvement and benefit increase due to the reasonable selection of the cooling medium of the polymerization kettle at different temperatures.

Description

technical field [0001] The invention relates to a process for producing polyvinyl chloride from crude vinyl chloride, which belongs to the technical field of polymer material science and engineering. Background technique [0002] Polyvinyl chloride, referred to as PVC, is a thermoplastic resin polymerized by vinyl chloride under the action of an initiator. It is a homopolymer of vinyl chloride. The physical appearance is white powder, non-toxic, odorless, and its chemical stability is very high. Has good plasticity. Polyvinyl chloride resin is the most widely used variety among the five general-purpose resins. It is widely used in many fields such as construction, automobiles, high-speed rail, ships, aerospace, and national defense. It plays a very important role in national economic and social development. The preparation methods of polyvinyl chloride include calcium carbide acetylene method and petroleum ethylene oxychlorination method. Due to the limitation of "poor oil"...

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Problems solved by technology

At the same time, in the vinyl chloride polymerization reaction section, the refined vinyl chloride monomer must be mixed with hot desalted water before it enters the polymerization kettle for polymerization. Currently, cold desalted water is mixed with vinyl chloride monomer after being heated by steam, and cold desalted water is mixed with vinyl chloride monomer. The heating of water consumes a lot of steam, which leads to an increase in energy consumption; and in order to reduce energy consumption in conventional processes, circulating water at 35°C has been used for cooling, but in the hot summer and autumn seasons, the cooling The cooling effect of the medium is not good, but prolongs the polymerization reaction time in the polymerization tank and reduces the output

Moreover, in the VCM compression section of the conventional process, the compression equipment generally uses piston compressors. The use of this equipment has the following disadvantages: 1. It is easy to cause leakage of vinyl chloride gas after long-term operation; 2. Large maintenance and long compression time , low efficiency; 3. High maintenance costs and high operating costs; 4. Heavy oil, easy to enter the rectification system to block the heat exchanger; 5. Low degree of automation and high safety risks

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