Coal-fired boiler staged combustion air depth air staged combustion low NOx control method

Abstract

A coal-fired boiler staged combustion air depth air staged combustion low NOx control method, by optimizing the air volume distribution and excess air coefficient of each combustion reaction area in the furnace height direction of the coal-fired boiler, the depth of the main burner area in the lower part of the furnace is realized. Staged air combustion; multi-stage auxiliary embering air nozzles are set in the low-oxygen combustion and reduction area between the main burner area and the embering area, and each auxiliary embering air nozzle is arranged on the front and rear walls of the boiler furnace and the left and right side walls, one by one. The appropriate amount of combustion air is sent into the stage area; multi-layer main combustion air nozzles are set in the combustion area above the furnace, which is beneficial to the combustion of coal powder and the gradual reduction of NOx regeneration. The invention realizes the gradual reduction of NOx produced in the low-oxygen combustion and reduction zone and the release and transformation of coke nitrogen, minimizes the regeneration of NOx in the burnout zone and the final NOx emission concentration, and simultaneously avoids slagging on the wall surface of the furnace , high-temperature corrosion and increased carbon content of fly ash can simultaneously reduce NOx concentration and carbon content of fly ash.

Description

technical field [0001] The invention relates to a technology in the field of boiler combustion, in particular to a low NOx control method for coal-fired boiler staged combustion air depth air staged combustion. Background technique [0002] At present, coal-fired boilers mainly use air staged combustion and deep air staged combustion to reduce the NOx emission concentration in the furnace, that is, in the NOx reduction zone space between the main combustion zone and the burnout zone, the oxygen concentration is rapidly reduced to below 5% or even close to zero. The formed strong reducing atmosphere reduces the NOx generated in the main combustion zone to nitrogen, and the NOx concentration at the outlet of the reducing zone is reduced to a lower level. However, since there are still a large amount of unburned reducing gas-phase nitrogen-containing intermediates and incompletely released coke nitrogen at the outlet of the reduction zone, the combustion atmosphere transitions ...

AI Technical Summary

Problems solved by technology

[0003] The present invention aims at the problem that the NOx emission concentration of the existing coal-fired boiler air staged combustion and deep air staged combustion is greatly increased due to the regeneration of NOx in the burnout zone, and proposes a coal-fired boiler staged burner air deep air staged combustion The low NOx control method can minimize the regeneration of NOx in the burnout zone and the final NOx emission concentration, while avoiding slagging and high-temperature corrosion of the water wall of the boiler in the reduction zone, and reducing the carbon content of fly ash caused by air staged combustion , while reducing NOx emission concentration and fly ash carbon content

Images