System and method for relieving blockage of air preheater through catalytic oxidation of escaping ammonia

Abstract

The invention relates to the field of industrial waste gas purification, environmental protection and energy, and specifically relates to a system and method for relieving blockage of an air preheaterthrough catalytic oxidation of escaping ammonia. The system comprises a boiler and a chimney, wherein the boiler is connected with the chimney through a flue; an air inlet channel is further formed in the boiler; and the flue is connected with the air inlet channel through the air preheater. The system is simple in structure, ozone is sprayed into the flue through an ozone spraying device, a catalyst layer is combined, the ozone and the escaping ammonia in flue gas are removed, the amount of the sprayed ozone is that the molar ratio of the escaping ammonia in the flue gas located between an SCR denitration reactor and the catalyst layer is more than or equal to 3, the thoroughness of escaping ammonia removal is guaranteed, and therefore the escaping ammonia is efficiently removed, the pressure difference of the air preheater is prevented from being increased, and blockage of the air preheater is effectively relieved.

Description

technical field [0001] The invention relates to the fields of industrial waste gas purification, environmental protection and energy, in particular to a system and method for catalyzing and oxidizing escaped ammonia to alleviate air preheater blockage. Background technique [0002] my country's energy endowment determines that coal-fired power generation will dominate in the short and long term. At present, all coal-fired power generation units have completed ultra-low emission transformation, and the removal of nitrogen oxides is mainly completed through SCR denitrification technology. SCR denitrification refers to the oxidation-reduction reaction of nitrogen oxides in the flue gas and ammonia gas sprayed into the SCR reactor under the catalytic action of the catalyst to achieve the purpose of removing nitrogen oxides. In this method, while removing nitrogen oxides, the unreacted ammonia gas will escape from the SCR outlet and combine with the SO in the flue gas. 3 A reac...

AI Technical Summary

Problems solved by technology

When some coal-fired units change in load, due to defects such as ammonia injection valve control and SCR flow field, excessive ammonia injection will cause large ammonia escape, and more ammonium bisulfate will be generated to bind fly ash in the flue gas and adhere to it. The air preheater is blocked on the heat exchange unit of the air preheater, which will cause the unit load to be limited and the power generation to be reduced in severe cases

At the same time, the large escaped ammonia will also affect the follow-up dust collector and induced draft fan, which may cause the efficiency of the dust collector to decrease and the output of the induced draft fan to be insufficient

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