Comprehensive treatment method and system for benzene chloride waste liquid

Abstract

The invention discloses a comprehensive treatment method and a comprehensive treatment system for chlorobenzene waste liquid, which comprise the following steps of: uniformly blending and mixing wasteliquor with different pH values collected in a centralized manner until the pH value is equal to 6-8, and then adding sodium sulfite to fully react until hypochlorite does not exist; subjecting the solution to standing layering, overflowing and standing layering, and feeding a separated water phase to a hydrochloric acid synthesis section of the device to absorb hydrogen chloride gas to prepare hydrochloric acid; then feeding the separated organic phase containing a certain amount of water into an intermediate product tank through iron removal and water removal, and conveying the acid liquidgenerated by iron removal and water removal and a water solution generated by regeneration to a hydrochloric acid synthesis procedure to synthesize hydrochloric acid. According to the method, hypochlorite removal, water removal and iron removal are carried out on the waste liquid generated in chlorobenzene production, so that the product and iron ions are recycled, the wastewater is recycled, zerodischarge of the wastewater is realized, and the requirements of clean production is realized.

Description

technical field [0001] The invention belongs to the technical field of three-waste treatment of chemical wastewater, and in particular relates to a comprehensive treatment method and system for chlorinated benzene waste liquid. Background technique [0002] Chlorinated benzene is an important organic chemical intermediate, widely used in the synthesis of dyes, pesticides, medicines, engineering plastics and other fields. At present, domestic production of chlorinated benzene is prepared by reacting benzene and chlorine in a chlorination reactor under the catalysis of ferric chloride. The ferric chloride and acid produced by the reaction are washed with water and alkali to remove HCl and ferric chloride in the chlorinated solution, and then rectified and purified to obtain the finished product of benzene chloride. The process is mature, but the consumption of clean water and alkali is large, the amount of waste water is large, and iron sludge of ferric hydroxide is produced....

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Problems solved by technology

[0004] For example, the patent document CN 102584523 A discloses a crude chloride solution washing and alkali washing device and a water washing and alkali washing method in the production of chlorinated benzene. The crude chloride solution enters the crude chloride solution storage tank through water washing and alkali washing, and the acid produced Water is neutralized with lye. This patent document solves the problem of continuous use of clean water and continuous discharge of waste acid water. However, a large amount of waste water produced by washing is still neutralized with lye. Neutralization will inevitably produce iron hydroxide. This document does not This part of the content is reported. In addition, the wastewater generated by alkali washing enters the crude chloride storage tank, and how to deal with it in the next step is also not introduced.

[0005] Patent document CN 103819306 A discloses a process for removing ferric chloride from the chlorinated liquid produced by the production of chlorinated benzene. It utilizes resin adsorption and analysis to effectively reduce the content of ferric chloride in the chlorinated liquid. A large amount of waste water is produced in the washing stage, which directly enters the waste water treatment, and does not really reduce the amount of chlorinated benzene waste water

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