A method for analyzing and determining the cause of fouling in a reverse osmosis system during the reuse of circulating water and sewage in a power plant and its chemical cleaning method

Abstract

The invention discloses a method for analyzing and determining the cause of the fouling of the reverse osmosis system in the recycling process of the circulating water sewage of the power plant and its chemical cleaning method. Cleaning method, the analysis shows that the main component of the fouling is calcium sulfate scale, which determines the difficulty of chemical cleaning. In actual operation, the fouling of calcium sulfate scale is difficult to remove by reverse osmosis equipment. Therefore the present invention adopts reverse osmosis chemical cleaning method, and its steps are: reverse osmosis system flushing, hydrochloric acid pickling, sodium carbonate+EDTA cleaning, hydrochloric acid cleaning. The present invention can utilize the existing on-line cleaning system of reverse osmosis to realize on-line cleaning of reverse osmosis calcium sulfate scale, and has simple operation, short time consumption, less impact on power plant water supply, simple and easy-to-obtain cleaning chemicals, and low cleaning cost.

Description

technical field [0001] The invention relates to a method for analyzing and cleaning the cause of fouling in a reverse osmosis system. Background technique [0002] Sewage reuse of circulating water is an effective way to solve the shortage of water resources in power plants and realize the reduction of sewage discharge and the utilization of sewage resources. Circulating water and sewage water quality components are complex, the salt content in water, SO 4 2- , Ca 2+ , Alkalinity and other indicators are doubled compared with natural water bodies. When it is reused for reverse osmosis treatment, it is very easy to cause reverse osmosis scaling, resulting in a decrease in reverse osmosis output, shortened operation cycle, frequent chemical cleaning, and power plants. Insufficient water supply will shorten the life of reverse osmosis membrane elements in severe cases, which greatly affects the stability of reverse osmosis operation in power plants. [0003] At present, in ...

AI Technical Summary

Problems solved by technology

Circulating water and sewage water quality components are complex, the salt content in water, SO 4 2- , Ca 2+ , Alkalinity and other indicators are doubled compared with natural water bodies. When it is reused for reverse osmosis treatment, it is very easy to cause reverse osmosis scaling, resulting in a decrease in reverse osmosis output, shortened operation cycle, frequent chemical cleaning, and power plants. Insufficient water supply will shorten the life of reverse osmosis membrane elements in severe cases, which greatly affects the stability of reverse osmosis operation in power plants

[0003] At present, in the operation of power plants that use circulating water and wastewater reuse, calcium sulfate scales often appear in the second stage of reverse osmosis. The water production rate of reverse osmosis decreases, the pressure difference increases, and the desalination rate decreases, which affects the operation stability.

At present, most reverse osmosis membrane elements can only be taken out after calcium sulfate fouling, and long-term off-line cleaning is performed, which not only affects the normal operation of reverse osmosis, but also affects the normal water supply of the unit, and the cleaning cost is high, which affects the economy of the power plant benefits, reducing the enthusiasm of power plants to reuse circulating water and sewage