Treatment method for recycling power plant circulating water sewage

Abstract

The invention discloses a treatment method for recycling power plant circulating water sewage, which comprises the following steps: sending circulating water sewage into a multimedia filter, and filtering; sequentially passing the effluent water through a primary sodium cation exchanger and a secondary sodium cation exchanger; replenishing part of the effluent water of the secondary sodium cation exchanger into a cooling tower as circulating water; sending the rest of treated effluent water into primary reverse osmosis to be treated; replenishing part of the primary reverse osmosis effluent water into the cooling tower as circulating water; sending the rest of the primary reverse osmosis effluent water into secondary reverse osmosis; and sending the effluent water of the secondary reverse osmosis into a deep desalting system to be treated, and using the treated effluent water as power plant boiler replenishing water. By using the two stages of sodium cation exchangers instead of the lime treatment system, the method prevents sludge and other refractory substances from generation. The reverse osmosis effluent water obtained by the treatment method has high quality, can be directly used as power plant heating network replenishing water, chemical make-up water treatment system water source and circulating water replenishing water.

Description

technical field [0001] The invention relates to a recycling treatment method for circulating water and sewage of a power plant. 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, COD, SiO 2 , hardness, alkalinity and other indicators are doubled compared with natural water, when it is reused for reverse osmosis treatment, it is very easy to cause reverse osmosis scaling and fouling, resulting in a decrease in reverse osmosis output, shortened operation cycle, and frequent Chemical cleaning and insufficient water supply to the power plant will shorten the life of the reverse osmosis membrane element in serious cases, which greatly affects the stability of the reverse osmosis operation of the power plant. [...

AI Technical Summary

Problems solved by technology

Circulating water and sewage water quality components are complex, the salt content in water, COD, SiO 2 , hardness, alkalinity and other indicators are doubled compared with natural water, when it is reused for reverse osmosis treatment, it is very easy to cause reverse osmosis scaling and fouling, resulting in a decrease in reverse osmosis output, shortened operation cycle, and frequent Chemical cleaning and insufficient water supply to the power plant will shorten the life of the reverse osmosis membrane element in severe cases, greatly affecting the stability of the reverse osmosis operation of the power plant

[0003] At present, reverse osmosis fouling often occurs in the operation of power plants that use circulating water and sewage reuse. Reverse osmosis has a decrease in water production, an increase in pressure difference, and a decrease in desalination rate, which affects operational stability.

At the same time, the current conventional reverse osmosis recovery rate is 75%, that is, about a quarter of the influent water is discharged directly as concentrated water without recycling, which is a big waste for the system

At the same time, lime coagulation is mostly used in the recycling of circulating water and sewage. For some power plants, the sludge produced by lime coagulation is difficult to deal with, which has caused a series of problems for the power plant's environmental protection.

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