a na + 、k + 、nh 4 + 、cl ‑ 、so 4 2‑ 、no 3 ‑ Comprehensive utilization method of high-concentration waste brine in coal chemical industry

Abstract

The invention relates to a comprehensive utilization method of high-concentration waste saline water containing Na<+>, Ka<+>, NH<4+>, Cl<->, SO4<2-> and NO<3-> in the coal chemical industry. After the high-concentration waste saline water is subjected to softening for impurity removal and subjected to coagulation sedimentation to remove COD (chemical oxygen demand), the water is concentrated by 20%-30% through an air cooler; then, the water enters second and third concentration systems and a salt mixture recovery system, and sodium sulfate, sodium chloride and sodium nitrate and potassium sulfate mixed salt are concentrated and separated with a multi-effect negative pressure evaporation method; condensed water is recycled. The purity of separated sodium chloride and the purity of separated sodium sulfate are higher than 99%, and sodium chloride and sodium sulfate can be directly sold. The method has remarkable economic benefits and social benefits, is environment-friendly, comprehensively reaches the standard and can be used for comprehensive treatment and utilization of similar high-concentration saline water in other industries, so that the environment-friendly and energy-saving requirements for full utilization of resources are met.

Description

technical field [0001] The invention belongs to the wastewater treatment link in the fields of coal chemical industry, new energy chemical industry, petrochemical industry, chemical fertilizer, etc., and specifically relates to + 、K + , NH 4 + , Cl - , SO 4 2- , NO 3 - Advanced treatment and comprehensive utilization of high-concentration waste brine from coal chemical industry. Background technique [0002] Coal chemical industry, methanol, ethylene glycol, olefins and other emerging energy, chemical and fertilizer enterprises, in the process of deepening the treatment and reuse of wastewater, mix the wastewater that meets the standard of the sewage treatment station, the concentrated drainage of the desalinated water station, and the sewage of the circulating water station. Afterwards, the waste water discharge reduction device is used for purification treatment, and the purified water is returned to the production process for recycling, and a small amount of Na-ri...

AI Technical Summary

Problems solved by technology

[0004] Since this part of the high-concentration waste brine contains relatively high inorganic salts and ammonia nitrogen, the COD is also high, so it cannot be discharged directly, nor can it be directly used

Individual enterprises use simple evaporation and concentration methods to concentrate them, but the concentrated inorganic salts are mixed together, and the chromaticity and appearance are poor, so they cannot be used or treated, and become secondary pollution, which is punished by the environmental protection department

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