Treatment method and treatment system for wastewater produced during flue gas desulfurization adopting limestone/lime-gypsum method

Abstract

The invention provides a treatment method for wastewater produced during flue gas desulfurization adopting a limestone/lime-gypsum method. The treatment method comprises steps as follows: (1), lime, sodium sulfate, a heavy metal precipitant, a flocculating agent and a coagulant are added to to-be-treated desulfurization wastewater, precipitation is performed, and acid is added to effluent for neutralization; (2), the effluent in the step (1) is subjected to electrodialysis treatment through a homogeneous-phase monovalent ion exchange membrane, and contributing water containing NaCl and concentrated water containing CaSO4 are formed and are recycled respectively. The invention further provides a treatment system for the wastewater produced during flue gas desulfurization adopting the limestone/lime-gypsum method. According to the treatment method and the treatment system, zero emission is realized, the process is simple, the treatment efficiency is high, waste recycling is realized, an available industrial product can be directly obtained, the agent cost, the equipment cost and the energy consumption are lower, and accordingly, the overall operation and management cost is obviously lower than the cost of a conventional technology.

Description

technical field [0001] The invention relates to the field of industrial wastewater treatment, in particular to a treatment method and system for limestone / lime-gypsum flue gas desulfurization wastewater. Background technique [0002] With the rapid development of my country's energy industry and the construction of large-scale coal-fired power plants, fuel consumption continues to increase, SO 2 The amount of emissions is increasing, and the resulting air pollution is also becoming more and more serious. At present, flue gas desulfurization is considered to control SO 2 The most efficient way to reduce emissions. Limestone / lime-gypsum wet flue gas desulfurization is the most widely used and most mature desulfurization process in China and in the world. Generally speaking, the limestone / lime-gypsum wet flue gas desulfurization of coal-fired power plants uses limestone slurry to spray in the absorption tower, and the SO in the flue gas 2 The reaction produces CaSO 3 , CaS...

AI Technical Summary

Problems solved by technology

[0007] (4) Contains Na + 、K + , Ca 2+ , Mg 2+ , Cl - , SO 4 2- , F - , NO 3- , heavy metal ions such as As, Cd, Cr, Hg and other components, the components are complex and the water quality changes with time and working conditions, sometimes to a greater extent

[0008] (5) High salt content, especially C1 - High content, coupled with acidic, very corrosive

[0023] The above-mentioned zero-discharge treatment processes for desulfurization wastewater all have certain defects, mainly including: 1) the process is relatively complicated; 2) the pretreatment process is long and the cost of operating chemicals for pretreatment is high; 3) the overall operating cost is high; 4) the overall High investment; 5) Complicated operation and management; 6) There is no effect of recycling waste or the effect is not obvious

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