Coking wastewater membrane concentration salt separation zero-emission treatment system and coking wastewater membrane concentration salt separation zero-emission treatment method

Abstract

The invention belongs to the technical field of water treatment, and particularly relates to a coking wastewater membrane concentration salt separation zero-emission treatment system and a coking wastewater membrane concentration salt separation zero-emission treatment method. The method comprises: coking wastewater pretreatment, wherein the coking wastewater pretreatment comprises full-automaticsand filtration, active carbon adsorption regeneration, ultra-filtration and softening; membrane salt separation and concentration treatment, wherein the membrane salt separation and concentration treatment comprises low-pressure nano-filtration, high-pressure nano-filtration, purification nano-filtration and reverse osmosis treatment; and concentration treatment, fluorine and silicon removal, electrodialysis concentration and evaporative crystallization, wherein an industrial-grade sodium chloride product with a purity of more than 92% is obtained, a sodium sulfate concentrated solution enters a freezing crystallization device to generate mirabilite, the mirabilite is heated and melted and then enters an evaporation crystallization, centrifugation and drying system, and an industrial-grade sodium sulfate product with a purity of more than 95% is obtained. According to the invention, with the system and the method, the zero discharge of coking wastewater is achieved, and the process technology is an innovative coking wastewater zero discharge process at home and abroad.

Description

technical field [0001] The invention belongs to the technical field of water treatment, and in particular relates to a zero-discharge treatment technology, system and method for coking wastewater membrane concentration and salt separation. Background technique [0002] The composition of coking wastewater is complex and changeable, and its composition and properties vary with the composition and properties of coal, carbonization temperature, and coal gasification and chemical product refining processes. Contained pollutants can be divided into two categories: inorganic substances and organic substances. Inorganic substances generally exist in the form of ammonium salts, and organic substances include phenolic compounds, aliphatic compounds, heterocyclic compounds, and polycyclic aromatic hydrocarbons. The organic components in coking wastewater are complex and difficult to degrade, and belong to the wastewater category that is difficult to treat. At present, the coking wast...

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Problems solved by technology

With the improvement of national environmental protection requirements, new coking enterprises and some areas with high environmental protection requirements have implemented new standards (Table 2 in GB16171-2012) and special discharge requirements (Table 3 in GB16171-2012). m 3 / t coke up to 0.4m 3 / t coke and 0.3m 3 / t coke, the wastewater discharge of most coking enterprises, especially newly built and renovated coking enterprises, cannot meet the new and special discharge requirements

A small number of coking enterprises evaporate and crystallize the concentrated water after coking wastewater film concentration to obtain industrial water and mixed salt. Since the mixed salt contains impurities such as organic matter, it is hazardous waste and the disposal cost is high.

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