Combustion system for reducing nitric oxides of front and back wall opposite-combustion boiler

Abstract

The invention relates to a combustion system for reducing nitric oxides of a front and back wall opposite-combustion boiler. The combustion system comprises a primary air fan, an air preheater, a combustor arranged on the lower portion of a hearth, a primary hot air pipe, a primary cold air pipe, a plurality of first layers of over fire air nozzles arranged on the upper portion of the hearth, and second layers of over fire air nozzles arranged on the upper portions of the first layers of over fire air nozzles. During operation of the combustion system, part of primary air generated by the primary air fan is sprayed into the combustor via a straight over fire air nozzle in the upper portion of the combustor; through cooperation of the combustor, a first layer of over fire air and a second layer of over fire air, combustible materials in flying ash of the hearth can be effectively reduced, the flue gas atmosphere near a water-cooling wall is improved, coking and high-temperature corrosion of the water-cooling wall are prevented, the oxygen content deviation of flue gas of the two sides of the hearth is reduced, the purpose of improving and controlling steam temperature is achieved, and the combustion system has excellent social and economic benefits.

Description

technical field [0001] The invention belongs to the field of thermal power generation equipment, and relates to a combustion system, in particular to a combustion system for reducing the nitrogen oxides of the front and back walls of a confronting combustion boiler. Background technique [0002] At present, the combustion methods in large pulverized coal combustion boilers mainly adopt four-corner tangential combustion and front and rear wall hedging combustion. Due to its advantages in combustion stability and heating surface layout, the front and rear wall opposed combustion boiler has become one of the main combustion methods currently used by boilers. In the opposite combustion mode of the front and rear walls, on the front wall of the swirl burner furnace and the water-cooled wall of the rear wall, each burner organizes the air distribution separately, and the flame is relatively independent. The flames of the burners on the front and rear walls entrain each other to c...

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Problems solved by technology

[0006] The purpose of the present invention is to overcome the above-mentioned shortcomings of the prior art, and provide a combustion system that reduces the nitrogen oxides of the front and rear walls of the opposing combustion boiler and improves the combustion efficiency of the boiler. Fly ash and combustibles generated later, coking of water wall, high temperature corrosion and difficulty in controlling steam temperature, etc.

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