Waste water treatment system and method for power plant

Abstract

The invention relates to a waste water treatment system and a waste water treatment method for a power plant. The system comprises a pre-treatment system, an evaporation and crystallization system, an ammonia nitrogen treatment system and a membrane condensation and treatment system, wherein the pre-treatment system is connected to waste water of the power plant; the ammonia nitrogen treatment system is connected between the pre-treatment system and the evaporation and crystallization system and connected to waste water treated by the pre-treatment system; and the membrane condensation and treatment system is arranged between the ammonia nitrogen treatment system and the evaporation and crystallization system. A small amount of ammonia nitrogen in system water is removed or the ammonia nitrogen content of the system water is lowered by using the ammonia nitrogen treatment system; the NH3 content of blow-off tail gas produced after blow-off is very low and fully meets the requirement of national atmospheric pollutant emission standard; and the ammonia nitrogen content of water is lowered by a blow-off method (or an oxidation method) so that running cost is lowered. Moreover, the concentration of waste water can be increased by membrane condensation and treatment technology and crystallization can be performed, so that the steam consumption of the evaporation and crystallization system and the running cost are reduced; and the NaCl content of crystal salt is increased so that the crystal salt reaches the quality standard of industrial salt and the aim of recycling waste materials is fulfilled.

Description

technical field [0001] The invention relates to a process system for treating sewage and wastewater, more specifically, to a system and method for treating desulfurization wastewater or wastewater containing salt in a power plant. Background technique [0002] The waste water generated in the process of flue gas wet desulfurization (limestone / gypsum method) in coal-fired power plants comes from the waste water discharged from the desulfurization absorption tower. In order to maintain the balance of substances in the slurry circulation system of the desulfurization unit, prevent the soluble part of the flue gas, that is, the chlorine concentration from exceeding the specified value, and ensure the quality of gypsum, a certain amount of wastewater must be discharged from the system. The wastewater mainly comes from the gypsum dewatering wastewater and cleaning system. The impurities contained in wastewater mainly include suspended solids, supersaturated sulfite, sulfate and he...

AI Technical Summary

Problems solved by technology

In addition, due to the complex composition of desulfurization wastewater, it is difficult to ensure that the composition of crystalline salt produced by evaporation treatment can meet the quality standards of industrial salt. The outlet for crystalline salt can only be transported as general miscellaneous salt.

This results in high operating costs and low quality crystallized salt, which is not conducive to reuse

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