Device and method for oxidizing and removing elemental mercury by using wet flue gas desulfurization wastewater

Abstract

The invention relates to a device and a method for oxidizing and removing elemental mercury by using wet flue gas desulfurization wastewater. The device comprises a boiler, wherein the boiler is connected with a SCR (Selective Catalytic Reduction) denitration device through a coal economizer; the SCR denitration device is connected with a limestone-gypsum wet desulphurization tower through an air pre-heater and a dust remover; a chimney is arranged on the limestone-gypsum wet desulphurization tower; atomizing nozzles are distributed in a flue between the coal economizer and the SCR denitration device; the atomizing nozzles are connected with a desulfurization wastewater tank through a slurry pump; an air compressor is connected with the atomizing nozzles and used for supplying compressed air for the atomizing nozzles in the atomizing process. By virtue of the device and the method, the problem that combustion low-chloride coal elemental mercury is difficultly discharged is solved, and the problem of treatment of the desulfurization wastewater is solved.

Description

technical field [0001] The present invention relates to a device and method for back-spraying desulfurization wastewater to realize oxidation and removal of elemental mercury, in particular to back-spraying of desulfurization wastewater in a limestone-gypsum wet flue gas desulfurization process before selective catalytic denitrification in the tail flue of a coal-fired boiler, for promoting The invention relates to a novel technique for oxidation and removal of elemental mercury in coal-fired flue gas, which belongs to the technical field of environmental protection. Background technique [0002] Mercury is a highly toxic class of pollutants in the atmosphere that can cause damage to the human nervous system. Flue gas emissions from coal-fired boilers in power plants are an important source of mercury in the atmosphere. Mercury is mainly in the form of elemental mercury (Hg 0 ), oxidized mercury (Hg 2+ ) and particulate mercury (Hg P ) in three forms. Among them, partic...

AI Technical Summary

Problems solved by technology

Desulfurization wastewater has complex components and high toxicity, which is a difficult point for water treatment in coal-fired power plants

[0004] Patent CN 103521052 A discloses a method for flue gas demercuration using desulfurization wastewater from coal-fired power plants, adding halogen additives and mercury removal catalysts to the desulfurization wastewater produced during the limestone-gypsum wet flue gas desulfurization process One or two, after being fully mixed, pumped to the flue between the air preheater and the dust collector, atomized and sprayed in the flue through the atomization device, fully contacted with the dust in the passing flue gas, and the flue gas The mercury in the desulfurization wastewater is removed, while the solid matter and flue gas dust in the desulfurization wastewater are captured and removed by the dust collector, and the zero discharge of the desulfurization wastewater is achieved while the flue gas is demercurized. In the process, halogen additives and mercury removal catalysts need to be added, which is highly dependent ,high cost

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