Chloroethylene constant temperature pressure-swing adsorption-desorption gas purification process

The invention belongs to the technical field of production of polyvinyl chloride resin by a calcium carbide method, and discloses a chloroethylene constant temperature pressure-swing adsorption-desorption gas purification process. Constant temperature pressure-swing adsorption-desorption gas enters an absorption tower in a pressurized manner through a Roots blower from a buffer tank and contacts with water in a reverse-flow manner, the gas enters a separator after powder is absorbed by the absorption tower, the gas is mixed with hydrogen chloride gas after being separated and dewatered, enters a graphite cooler together with the hydrogen chloride gas and is cooled to reach -12 to -18 DEG C, and water mists are removed by a demister, so that purified product gas is obtained. The inlet amount of the hydrogen chloride gas is not smaller than 12% of the total volume of mixed gas. The influence of the powder on a converter can be effectively avoided, the problem that desorption gas entrains white powder is effecti