Limestone-gypsum desulfurization wastewater chloride ion extraction system

Abstract

The invention discloses a limestone-gypsum desulfurization wastewater chloride ion extraction system. A desulfurization wastewater inlet pipeline is communicated with an inlet of a pretreatment system, an outlet of the pretreatment system is communicated with an inlet of an extraction phase splitter through an extraction reactor, an extract outlet of the extraction phase splitter is communicated with an inlet of the back extraction phase splitter sequentially through a back extraction reactor, an organic phase NR3 outlet of a back extraction phase splitter is communicated with an inlet of a centrifuge, a waste liquid outlet of the back extraction phase splitter is communicated with an inlet of a waste liquid recoverer, a waste liquid outlet of the centrifuge is communicated with an inlet of the waste liquid recoverer, and an outlet of a diluent storage tank and an outlet of an extractant storage tank are communicated with an inlet of a dilution tank; and a water phase outlet of the extraction phase splitter is communicated with the inlet of a clean water tank, and the outlet of the clean water tank is communicated with the inlet of the extraction reactor. According to the present invention, with the system, the treatment and the reuse of the desulfurization wastewater are achieved, the treatment cost is low, and the zero emission is achieved.

Description

technical field [0001] The invention belongs to the technical field of waste water treatment in thermal power plants, and relates to a chloride ion extraction system for limestone-gypsum desulfurization waste water. Background technique [0002] At present, most of the wet flue gas desulfurization methods in thermal power plants in the country adopt the limestone-gypsum method for desulfurization. Chloride ions in process water, hydrogen chloride in flue gas and chloride ions in limestone continuously enter the desulfurization slurry for enrichment. Chloride ions reach a certain level. After concentration, part of the desulfurization slurry must be discharged, and the discharged part is desulfurization wastewater. Therefore, the content of chloride ions in desulfurization wastewater is very high, which will corrode equipment and pipelines and cannot be reused. [0003] At present, the removal methods of chloride ions in desulfurization wastewater include chemical precipitati...

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Problems solved by technology

The chemical precipitation method has a high removal efficiency for chloride ions, but the cost of chemicals is expensive, and the cost of large-scale use in the industrial field is too high; the ion exchange method is commonly used, but the concentration of sulfate ions in desulfurization wastewater is extremely high, and its exchange order is before chloride ions. Affect the chlorine ion exchange effect; evaporation and crystallization method has high energy consumption, easy scaling, and high cost; membrane separation method has high requirements on water quality, and the concentration of suspended solids in desulfurization wastewater is high, which is easy to cause membrane fouling; High consumption, resulting in high operating costs, suitable for desulfurization wastewater with low concentration and small water volume

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