Method for treating coal chemical industry sewage

Abstract

The invention relates to a method for treating coal chemical industry sewage, which is a breakthrough in coking industry sewage treatment and mainly solves the problem that macromolecular substances in coking sewage can not be easily degraded. In the development process, the formation structure of the substances is analyzed: the larger the molecular weight is, the stronger the intermolecular power is, and the higher the boiling point of the substance is. Since nondegradable substances and degradable substances have different boiling points, the nondegradable substances in the coking sewage can be separated by a technical line of concentration by evaporation; and since the condensed sewage containing micromolecular substances, which is separated by evaporation, has strong biochemical quality and low salinity, the condensed sewage can easily reach the standard when being subjected to biochemical sewage treatment, and the treated water can be directly used as compensation water of circulating water, thereby recycling the sewage. The technology is mainly used in high-concentration coking sewage treatment industry, and can also extend to nondegradable-substance-containing sewage treatment in coal chemical industry.

Description

technical field [0001] The invention belongs to the field of sewage treatment in the coal chemical industry and is a breakthrough in the sewage treatment technology of the coal chemical industry. It is mainly applied to solve the problem of difficult degradation of macromolecular substances in coal chemical sewage such as coking, so as to completely solve how to treat the sewage in the coking industry to meet the standard. , and then realize the reuse of water resources, and also provide a new technology for solving the sewage treatment in the coal chemical industry (coking, chemical fertilizer, coal oil, methanol, coal tar processing, crude benzene processing). Background technique [0002] 1. Generation of coking wastewater [0003] Coking wastewater is wastewater generated during the process of coke, gas purification and coking product recovery. Its main sources are: [0004] 1) Residual ammonia water, which is the sewage generated during coal dry distillation and gas...

AI Technical Summary

Problems solved by technology

6. Common disadvantages of existing processes

[0023]1) Always unable to meet the increasing national pollutant discharge standards, due to the carcinogenicity of NH3-N and BaP in coking sewage A large amount of aromatic hydrocarbons and fused ring aromatic hydrocarbons exist, and ordinary biochemical treatment processes can no longer meet environmental protection requirements.

[0024]2) Wastewater is highly toxic, among which cyanide, thiocyanide, aromatic ring, condensed ring, and heterocyclic compounds are toxic to microorganisms, and some even The concentration has exceeded the tolerance limit of microorganisms; in order to reduce the toxicity of wastewater, a large amount of water is used to dilute it, which not only wastes water resources, but also turns clean water into sewage. , but the total amount of pollutant emissions did not decrease

[0025]3) In the same industry, sewage treatment mostly adopts "physicochemical + biochemical + coagulation", mainly biochemical; biochemical mainly adopts "anaerobic + aerobic", The purpose of anaerobic is to break the molecular chain or ring shape of the difficult-to-biochemical substances in the sewage, and turn them into branched or short-chain hydrocarbons, but in fact, the ability of anaerobic is limited, and the inert and difficult-to-degrade macromolecular organic matter is difficult to break Molecular chains, the aerobic stage can not remove macromolecular organic matter;

[0026]4) High chroma, unable to meet emission requirements;

[0027]5) In the process of physicalization and coagulation, many metal ions are added, so the difficulty and cost of subsequent advanced treatment are increased

However, this method requires that the ammonia nitrogen content in the sewage after ammonia distillation is lower than 50mg / L, and the volume of the evaporated residual concentrated liquid does not exceed 5% of the original sewage volume, resulting in excessive evaporation. On the one hand, the energy consumption of evaporation is relatively high; On the other hand, excessive evaporation will make the content of macromolecular organic matter that is difficult to degrade in the steam condensed sewage too high, which increases the difficulty of biological treatment. Moreover, since the content of ammonia nitrogen is lower than 50mg / L, it is not conducive to biochemical degradation. Before treatment, it is necessary to increase the nitrogen source

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