Wet-type ammonia flue gas purification technics for associated desulfuration demercuration and system

Abstract

The invention relates to a wet ammonia flue gas purification process for the combined sulfur and mercury removing and the system thereof. The process adopts chlorine gas as oxidizing agent to completely oxidize elemental mercury in the flue gas, and gas phase divalent mercuric ion after being oxidized is converted into liquid phase divalent mercuric ion through the improved wet ammonia desulphurization process, and further the liquid phase divalent mercuric ion is converted into stable mercuric sulfide sendimentation through liquid phase divalent mercuric ion stabilizing agent. The system comprises a flue gas oxidizing demercuration preprocessing system composed of an oxidizing agent injection device and an electrostatic precipitator, a wet ammonia flue gas sulfur and mercury removing system composed of a reaction absorbing tower, a sulfur removing accessory substance processing system composed of a cyclone cleaner, a dewaterer, and a dryer, and a mercuric sulfide HgS sendimentation processing system composed of a wastewater buffer pool, a liquid phase mercuric ion reaction chamber, and a settling pond. The process and the system can effectively improve the oxidation rate of the elemental mercury in the flue gas, overcome the defaults that the divalent mercuric ion is easy to be reduced and released and the secondary pollution problem is caused by excess oxidizing agent, and greatly improve the efficiency of sulfur removing and mercury removing.

Description

technical field [0001] The invention relates to a flue gas purification treatment technology of a coal-fired power station, in particular to a combined desulfurization and mercury removal wet ammonia flue gas purification method and system thereof. Background technique [0002] Coal is the main fuel for power stations in China at present and for a long time to come. While pulverized coal combustion provides the necessary heat and power resources, it will also bring serious mercury Hg and sulfur dioxide SO 2 pollute. According to statistics, in 2003, my country's coal-fired power plants emitted 86.8 tons of mercury into the atmosphere, and 28.94 tons of mercury in waste residues. Mercury has the characteristics of high toxicity, high volatility, easy deposition in organisms, and long hysteresis The pollution of mercury emitted into the atmosphere is global. In 2005, the total amount of sulfur dioxide discharged by coal-fired power stations in my country was as high as 25.49 ...

AI Technical Summary

Problems solved by technology

This method is based on the wet ammonia desulfurization system, which can not only effectively improve the oxidation rate of elemental mercury in the flue gas, but also effectively overcome the reduction and release defects of the generated divalent ion mercury, and can effectively solve the secondary pollution caused by excessive oxidants. Pollution problems, thereby greatly improving the desulfurization and mercury removal efficiency of the wet ammonia desulfurization system

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