Method for reducing harmful materials in by-product hydrochloric acid in production process of chlorobenzene

Abstract

The invention provides a method for reducing harmful materials in by-product hydrochloric acid in a production process of chlorobenzene. The method comprises the following steps: compressing normal-temperature hydrogen chloride gas separated by a chlorobenzene system to 0.08-0.12MPa through a Roots blower, condensing the hydrogen chloride gas through a primary condenser, condensing water and low-boiling-point materials, separating the hydrogen chloride gas through a gas-liquid separator, then continuously compressing the hydrogen chloride gas to 1-1.5MPa through a compressor, condensing the hydrogen chloride gas through a secondary condenser for further removing organic impurities, filling the hydrogen chloride gas into an adsorption tower from the bottom of the adsorption tower with adsorbent, removing other impurities to obtain qualified hydrogen chloride gas, absorbing the qualified hydrogen chloride gas through water and then obtaining industrial pure hydrochloric acid. The purityof hydrogen chloride obtained by the method is high; the quality of the by-product hydrochloric acid is high; the wastewater is not generated; the enterprise income is increased; meanwhile, the methodis simple in process and easy to operate; the benzene-series organic matters recycled from the by-product hydrochloric acid enter a benzene recycling tank and return to the chlorination process for recycling, so that the material loss is reduced, and the production cost is reduced.

Description

technical field [0001] The invention relates to the technical field of pesticide production, in particular to a method for reducing harmful substances in by-product hydrochloric acid in the production process of chlorinated benzene. Background technique [0002] Chlorobenzene, also called chlorobenzene, is a colorless, transparent, volatile liquid with a bitter almond smell. Melting point -45.6°C, boiling point 131.6°C, relative density 1.107 (20 / 4°C), refractive index 1.5248, flash point 23°C, autoignition point 637.78°C, flammable. The explosion limit in air is 1.83-9.23% (volume). Insoluble in water, easily soluble in alcohol, ether, benzene and chloroform, etc. Toxic, moderately toxic. [0003] Chlorinated benzene is an important basic organic synthesis raw material, used as dyes, medicines, pesticides, and organic synthesis intermediates. It is used in the manufacture of phenol, nitrochlorobenzene, dinitrochlorobenzene, aniline, nitrophenol and the pesticide DDT, et...

AI Technical Summary

Problems solved by technology

In the traditional process of producing chlorinated benzene, benzene and chlorine gas are mixed and reacted in a chlorination reactor under the action of a catalytic iron ring catalyst. The method converts hydrochloric acid into gaseous hydrogen chloride and takes it out from the chlorination solution, and then absorbs the by-product hydrochloric acid through water, but the separated hydrogen chloride gas will entrain organic substances such as benzene and chlorinated benzene, making the quality of by-product hydrochloric acid poor, which cannot meet the requirements for hydrochloric acid. demanding production needs

A small amount of organic matter remaining in the by-product hydrochloric acid is taken out of the system with the hydrochloric acid, resulting in waste of raw materials and increasing production costs. At the same time, the brought in organic matter causes unsafe hidden dangers in the hydrochloric acid system