Flue gas mercury removal system based on photochemical advanced oxidation

Abstract

The invention provides a flue gas mercury removal system based on photochemical advanced oxidation, which comprises a burning and discharging system composed of a burner, an electrostatic precipitator, a heat exchanger, a spray tower, a liquid-filling tower, a chimney and a knockout tower, wherein the flue gas generated by the burner is fed into the heat exchanger for carrying out refrigeration after removing particulate matters in the electrostatic precipitator, and then is fed into the spray tower; the spray tower is internally provided with ultraviolet tubes; hydrogen dioxide solution coming from the liquid-filling tower is extracted by a circulating pump, and then is sprayed into the spray tower by an atomizing nozzle; hydrogen peroxide is excitated and decomposed by ultraviolet lights in the spray tower to generate a hydroxyl radical (.OH) with strong oxidability which generates gas-liquid absorption reaction with the flue gas in the spray tower, thereby removing HgO in the flue gas by oxidation; the flue gas being subject to absorption and washing is fed into the chimney for discharging from the top of the spray tower; the HgO generated in the spray tower is oxidized to be soluble Hg<2+> which is fixed in the solution; the solution is sucked into the knockout tower by the circulating pump and then generates HgS to Hg<2+> with the added Na2S solution so as to perform capture recycle to realize the flue gas demercuration.

Description

technical field [0001] The invention relates to mercury emission pollution control technology in flue gas including power plant boilers, industrial kilns and garbage incinerators, and in particular to a flue gas mercury removal system based on photochemical advanced oxidation. Background technique [0002] Mercury is a heavy metal trace element with high toxicity, high volatility, easy deposition in organisms and long hysteresis, which is extremely harmful to human health and ecological environment. Studies have shown that industrial processes such as thermal power generation, waste incineration, and cement and metallurgy powered by fossil fuels are important sources of man-made mercury pollution, and about 70% of them come from coal combustion in thermal power plants. my country is the world's largest coal consumer, and the proportion of coal in the energy structure is as high as 75%, and this pattern will not change significantly in a relatively long period of time in the ...

AI Technical Summary

Problems solved by technology

According to the double-membrane theory, Hg 0 It must first be transferred from the gaseous state to the liquid phase through the process of mass transfer and diffusion, and then the chemical reaction can occur and be fixed in the absorption liquid, Hg 0 The insoluble characteristics greatly increase the resistance of its liquid phase absorption, and it is difficult to significantly increase Hg only by adjusting pH and temperature. 0 Solubility in the liquid phase, this characteristic has caused the common problems of low removal efficiency and high energy consumption in traditional wet mercury removal technology, which hinders its industrial application

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