A flue gas collaborative denitrification and mercury removal system and method

Abstract

The invention belongs to the relevant technical field of energy saving and emission reduction, and discloses a smoke synergistic-denitration-demercuration system. The smoke synergistic-denitration-demercuration system comprises a pretreatment system, an injection system, a control system and a SCR system, wherein the injection system is connected with the pretreatment system and the SCR system; the pretreatment system, the injection system and the SCR system are connected to the control system; the smoke synergistic-denitration-demercuration system is connected to a furnace through the SCR system; the pretreatment system is used for mixing an ammonium chloride solution and ammonia water and delivering the obtained mixed liquid to the injection system; a catalyst is contained in the SCR system, and products obtained after the catalyst and the solution are fused and decomposed are jointly used for oxidizing mercury in smoke from the furnace. The invention also relates to a smoke synergistic-denitration-demercuration method. According to the smoke synergistic-denitration-demercuration system and method, the oxidation efficiency of mercury is improved, the structure is simple, and thecost is low.

Description

technical field [0001] The invention belongs to the technical field related to energy saving and emission reduction, and more specifically relates to a flue gas collaborative denitrification and mercury removal system and method. Background technique [0002] For the emission of air pollutants from thermal power plants, the emission limit of atmospheric mercury from thermal power plants is 0.03mg / m 3 , nitrogen oxide emission limit is 100mg / m 3 , which is a huge challenge to my country's coal-fired power plants, so we must strengthen the control of flue gas emissions from power plant boilers. [0003] SCR (Selective Catalytic Reduction) flue gas denitrification system is currently the main device for removing nitrogen oxides and oxidizing elemental mercury in coal-fired power plants. When the flue gas discharged from coal-fired boilers passes through the SCR catalyst, it will be injected into Flue NH 3 Mixed, NO in flue gas x will be reduced to N by reducing ammonia 2 ;...

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Problems solved by technology

[0004] SCR denitrification system for Hg 0 The oxidation efficiency is usually related to the SO in the flue gas 2 , HCl and NH 3 and other gas concentrations, and those skilled in the art have done some research on this. For example, patent CN 104399360 A discloses a NOx and mercury joint removal process and device based on SNCR-SCR combination, but in this process, NH 4 The HCl produced by the decomposition of Cl at the SNCR will react with the alkaline substances in the fly ash in the flue when it does not enter the SCR system. Affected by coal types and working conditions, the oxidation efficiency of catalysts for elemental mercury fluctuates greatly

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