Recycling method of residual liquor in production of trichloroethylene

Abstract

The invention relates to a recycling method of residual liquor in the production of trichloroethylene. The method comprises the following steps: residual liquor is collected in a top solution container and enters an alkaline washing tower to neutralize the acid in the residual liquor; the pretreated residual solution enters a distillation kettle to perform distillation, wherein the temperature ofthe distillation kettle is kept to 85-95 DEG C and dichloroethylene, trichloroethylene and tetrachloroethylene are distilled; the distilled dichloroethylene, trichloroethylene and tetrachloroethyleneenter a rectifying tower to perform atmospheric distillation, wherein dichloroethylene is distilled at 42+ / -1 DEG C, trichloroethylene is distilled at 87+ / -1 DEG C and tetrachloroethylene is distilled at 121+ / -1 DEG C; when the pressure of the distillation kettle is vacuumized to -80kPa, tetrachloroethylene is separated at 90+ / -1 DEG C and pentachloroethane is obtained in the distillation kettle.According to the method in the invention, all the components of the residual liquor can be completely separated, the zero emission of residues can be realized, the whole production process can realize closed circulation, the pollutions to the environment can be reduced, the residual liquor can be fully utilized, the recycling rate is high and the product yield can be increased.

Description

technical field [0001] The invention relates to a method for recovering raffinate in trichlorethylene production, which belongs to the technical field of chemical industry. Background technique [0002] In the production process of trichlorethylene, the amount of residue and raffinate generated is very large, and the volume ratio of each main component in the residue and raffinate is: tetrachloroethane 30%; trichlorethylene 30%; tetrachloroethylene 10% %; pentachloroethane 10%; trichloroethane 10%; other 10%, the components in the raffinate are relatively complex and have similar boiling points, so it is difficult to completely separate them through rectification. The usual treatment method is to directly discharge these residues and residual liquids into the environment, which will seriously pollute the environment and bring great potential safety hazards. Serious environmental pollution has always been the main factor affecting the production of trichlorethylene. [0003...

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Problems solved by technology

[0003] At present, the measures taken by trichlorethylene production enterprises for residues and raffinate: measure and compare the regeneration effects of several adsorbents on the adsorption of trichlorethylene and different regeneration methods, adopt temperature and pressure swing adsorption, and use purified gas to heat the regeneration adsorbent to desorb The process of removing and recovering trichlorethylene, using the above process to recover the residue and residual liquid, has huge construction equipment, complicated process, consumes a lot of energy, serious pollution, high recovery cost and low recovery rate

[0004] For example, the application number is 931115957, and the publication date is the Chinese patent on September 14, 1994, which discloses a kind of trichlorethylene refining method, through rectification and purification, filtering to remove impurities, cleaning and packaging to finished products; Before the purification by distillation, go through two processes of purification and drying to remove water; the first purification is to put industrial grade trichlorethylene into the reaction pot, add 1.5 times the weight of trichlorethylene in distilled water containing silver ammonia solution, and carry out mechanical stirring for 2 hours. After standing still for 30 minutes to separate layers, absorb the upper layer of water; dry and remove water into the purified trichlorethylene, add color-changing silica gel with a volume ratio of about 1 / 10 of trichlorethylene, shake fully to make the trace water be absorbed by the silica gel Adsorption, static filtration, take out trichlorethylene, the disadvantage is that more waste water is generated, the quality of recovered trichlorethylene is poor, and the purity is low

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