Multi-grade air combustion-supporting ultra-low-nitrogen combustor

Abstract

The invention belongs to the field of ultra-low nitrogen combustors, and particularly discloses a multi-grade air combustion-supporting ultra-low-nitrogen combustor. The multi-grade air combustion-supporting ultra-low-nitrogen combustor comprises a fire observation hole, a flame monitoring hole, a secondary combustion cylinder, a shell, a secondary combustion head and a central combustion head; anindependent central combustion-supporting air passage and a central fuel passage are adopted, and the central combustion-supporting air passage and the central fuel passage can be independently controlled, the combustion-supporting components of the air do not change with the change of a combustion load, so that the independence of combustion can be kept all the time, and the combustor can ensurestable combustion of the center fuel and can ensure that the center fuel is not affected by the outside smoke components. According to the scheme, a central open fire is adopted to directly ignite the secondary fuel to stabilize flames, and the multi-grade air combustion-supporting ultra-low-nitrogen combustor has obvious difference in stabilizing flames compared with the traditional mode of continuously igniting the flames by means of high-temperature flue gas backflow, the flame-stabilizing effect is obviously improved, the multi-grade air combustion-supporting ultra-low-nitrogen combustorcan keep the flame absolutely stable, and can ensure that excellent low NOX emission is achieved.

Description

technical field [0001] The invention relates to the technical field of ultra-low nitrogen burners, in particular to a multi-grade air-supporting ultra-low nitrogen burner. Background technique [0002] The NO of the current ultra-low nitrogen burner X Emission target values ​​are all below 30mg / Nm 3 Yes, the general technical route is to adopt the flue gas external circulation technology. Especially the large-scale ultra-low nitrogen burner supporting more than 10 tons of boilers. The flue gas external circulation is to recirculate the flue gas after fuel combustion to the inside of the burner, mix the flue gas with combustion-supporting air, and then mix with fuel to support combustion. Because only a very small amount of oxygen is contained in the flue gas composition after combustion, generally only about 3-4%. Therefore, after the flue gas external circulation is adopted, the oxygen content in the combustion air is reduced from the original 20.9% to less than 18%, an...

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Problems solved by technology

[0003] Using this method of flue gas external circulation can indeed reduce the NO produced by combustion X , but it also brings some negative effects. 1. Due to the larger air volume, the air velocity will increase under the condition of the same structure. After the velocity is too high, the flame will be defired and the combustion will be unstable; 2. In the combustion-supporting air The oxygen content decreases, the oxygen activity around the fuel becomes lower, and the combustion instability caused by the same

All of these make the failure rate of the burner significantly increase during operation

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