Differences in PVC production technology

聚氯乙烯的生产工艺有两种，一种是氯化法，一种是乙炔法。

There are two production processes of PVC, one is chlorination process, the other is acetylene process.

（1）电石乙炔法工艺

Brief introduction of calcium carbide acetylene process

该方法是在氯化汞催化剂存在下，由乙炔与氯化氢加成直接合成氯乙烯( VCM) ，然后经聚合制得聚氯乙烯。其生产过程可分为乙炔制备和净化，氯乙烯合成、产品精制及氯乙烯聚合。这一制法工艺和设备较简单，投资低，收率高； 但能耗大， 原料成本高，催化剂汞盐毒性大，故受环境保护等所制约。

The method is to directly synthesize vinyl chloride (VCM) by the addition of acetylene and hydrogen chloride in the presence of mercuric chloride catalyst, and then polymerize to obtain polyvinyl chloride. The production process can be divided into acetylene preparation and purification, vinyl chloride synthesis, product refining and vinyl chloride polymerization. This method has simple process and equipment, low investment and high yield; However, due to the large energy consumption, high raw material cost and high toxicity of catalyst mercury salt, it is restricted by environmental protection.

（2）乙烯氧氯化法工艺

Brief introduction of ethylene oxychlorination process

目前，国内比较流行的乙烯氧氯化法生产VCM工艺由8 个单元组成, 即乙烯直接氯化、乙烯氧氯化、二氯乙烷( EDC) 精馏、EDC 裂解、HCl 加氢脱炔、VCM 精制、废水处理和焚烧。乙烯氯化分为低温法( 50 ℃ ) 、中温法( 90 ℃ ) 及高温( 120 ℃)。

At present, the ethylene oxychlorination process for VCM production, which is popular in China, is composed of eight units, namely, direct ethylene chlorination, ethylene oxychlorination, dichloroethane (EDC) rectification, EDC cracking, HCl hydrogenation and acetylene removal, VCM refining, wastewater treatment and incineration. Ethylene chlorination is divided into low temperature method (50 ℃), medium temperature method (90 ℃) and high temperature method (120 ℃).

乙烯氧氯化法的主要优点是利用二氯乙烷热裂解所产生的氯化氢作为氯化剂，从而使氯得到了完全利用。由于电石乙炔法较简单，而乙烯法流程较长，因此投资大，但后者的氯可完全利用，“ 三废”均可处理而不排出。

The main advantage of ethylene oxychlorination method is that hydrogen chloride generated from the thermal cracking of dichloroethane is used as the chlorinating agent, so that chlorine can be fully utilized. As the calcium carbide acetylene process is relatively simple and the ethylene process is relatively long, the investment is large, but the chlorine of the latter can be fully utilized, and the "three wastes" can be treated without discharge.

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