Power plant desulfurization wastewater advanced treatment and resource utilization system and method

Abstract

The invention provides a power plant desulfurization wastewater advanced treatment and resource utilization system and method. The system comprises a boiler, an air preheater, an electric dust remover, a low-temperature concentration unit, a flue gas wet desulfurization absorption tower and a chimney which are sequentially communicated through flues, the bottom of the absorption tower is communicated with a gypsum slurry dehydration unit, a water outlet of the dehydration unit is communicated with the low-temperature concentration unit, the low-temperature concentration unit is communicated with a wastewater regulating tank, and desulfurization wastewater is concentrated by the low-temperature concentration unit and enters the wastewater regulating tank, the bottom of the wastewater regulating tank is communicated with a sludge treatment unit, the wastewater regulating tank is sequentially communicated with a high-density sedimentation tank, a multi-medium filtering unit, a nanofiltration unit and an evaporative crystallization unit, and the bottom of the high-density sedimentation tank is communicated with the sludge treatment unit. The method comprises the following steps: concentrating the wet desulphurization wastewater, softening the wastewater by adjusting the pH value and a sedimentation tank, reducing the content of suspended matters and heavy metals, further filtering,evaporating and crystallizing, and recovering industrial salt and fresh water.

Description

technical field [0001] The invention relates to the technical field of wastewater treatment, in particular to a system and method for advanced treatment and resource utilization of power plant desulfurization wastewater. Background technique [0002] At present, my country's power structure is dominated by coal-fired unit thermal power generation, and for a long period of time, my country will still maintain the dominant position of coal-fired power generation. The control of air pollutants emitted by thermal power plants represented by sulfur dioxide will directly affect the quality of my country's air environment. [0003] Wet desulfurization is the most widely used flue gas desulfurization process in thermal power plants. The desulfurization wastewater produced is a complex sewage with high suspended solids content, high salt content, high hardness, high chloride ion content, COD , fluoride, heavy metal content exceeded the characteristics. With the country's requiremen...

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Problems solved by technology

[0004] At present, the process route of "pretreatment + concentration reduction + terminal solidification" is often used, but the existing desulfurization wastewater treatment process has a low recovery rate of wastewater, unstable system operation, and the quality of fresh water produced is not high. Evaporation is commonly used for concentration reduction. The energy consumption of crystallization technology is high, and the membrane method is easy to foul and clog, resulting in the increase of operating costs and low energy utilization.

In addition, the neutralization, softening, flocculation, precipitation, clarification and other processes in the traditional multi-stage dosing pretreatment technology are carried out multiple times, which has the disadvantages of long process flow, large dosage of chemicals, many structures, large floor area, and processing The problem of inefficiency

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