Method for separating organic matter impurities from brine waste of coal chemical industry and separating salt by utilizing membrane method

Abstract

The invention discloses a method for separating organic matter impurities from brine waste of a coal chemical industry and separating salt by utilizing a membrane method. The method comprises the following steps: (1) efficient reverse osmosis process; (2) nanofiltration process; (3) electroosmosis process I; (4) evaporative crystallization process I; (5) electrolytic oxidation process; (6) electroosmosis process II; and (7) evaporative crystallization process II. The invention abandons the traditional scheme for separating the salt in the manner of high-quality crystal separation through freezing crystallization or thermal method at the rear end and adopts a nanofiltration membrane process for separating the salt. The selective permeability of the nanofiltration membrane for ions under different valence states is utilized to separate the two main components, namely, sodium chloride and sodium sulfate in the waste water. The defects that the water quality change cannot be coped with and the product purity is low in the traditional salt niter separation hot-process crystallizing scheme can be overcome.

Description

technical field [0001] The invention belongs to the field of coal chemical industry, and in particular relates to a method for separating organic impurities and salt in high-salt wastewater of coal chemical industry by using a membrane method. Background technique [0002] The coal chemical process is an industry that converts coal into gas, liquid, and solid products or semi-products, and then further processes them into chemical and energy products. The actual characteristics of my country's energy resources are lack of oil and gas, relatively abundant coal resources, and relatively low coal prices. Therefore, the coal chemical industry has huge market demand and development opportunities in China. The new coal chemical industry will play an important role in the sustainable process of China's energy. It is of great significance for China to reduce environmental pollution caused by coal burning, reduce dependence on imported oil, and develop the domestic economy. [0003]...

AI Technical Summary

Problems solved by technology

[0004] As far as coal chemical projects currently in operation in China are concerned, two to three coal chemical projects have achieved "zero waste water discharge", but there are also serious defects; for a project in Inner Mongolia that has been successfully operated, due to COD In the process of zero discharge, the separation is not good, the stable operation of the terminal crystallization process is difficult to be guaranteed, the water quality of the recovered condensate is difficult to meet the standard, the output crystalline salt is brown, and the main salt components are not separated, and the resource utilization of crystalline salt cannot be realized.

If this situation cannot be reasonably improved, it will not only affect the environment, but also seriously affect the economic benefits of the factory.

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