Deep denitration process for supercritical carbon dioxide coal-fired boiler

Abstract

The invention discloses a deep denitration process for a supercritical carbon dioxide coal-fired boiler, belonging to the technical field of NOx emission reduction. The deep denitration process comprises the following steps: three-stage ammonia injection denitration, wherein an ammonia injection combustor is used for injecting a fuel and an amino reducing agent into a main combustion area of a combustor in a boiler to form an annular high-temperature low-oxygen reduction area with a temperature of 850-1400 DEG C, and a reduction reaction is carried out in the annular high-temperature low-oxygen reduction area to achieve first-stage denitration, and a second-stage ammonia injection device and a third-stage ammonia injection device are used for respectively injecting an amino reducing agentto a main combustion area at the upper part of the high-temperature low-oxygen reduction area and a burnout area behind burnout air to realize second-stage denitration and third-stage denitration; anddedusting, desulfurization and denitrification, wherein SCR denitrification is conducted on the flue gas in a dedusting and denitrification unit, and then the flue gas is cooled to 70-90 DEG C and then sent into the boiler for circular denitrification treatment. The defect that the denitration degree is insufficient due to the fact that the temperature of the supercritical carbon dioxide coal-fired boiler is high in the prior art is overcome, deep staged denitration in the boiler is achieved through the three-stage ammonia injection denitration process, the temperature in the boiler is effectively reduced through low-temperature flue gas recirculation combustion, generation of thermal NOx is reduced, and deep denitration of the supercritical carbon dioxide coal-fired boiler is achieved.

Description

technical field [0001] The invention belongs to the technical field of NOx emission reduction, and more specifically relates to a deep denitrification process of a supercritical carbon dioxide coal-fired boiler. Background technique [0002] In the coal-fired power generation boiler system where water is used as the circulating working medium, the heat transfer characteristics of water vapor cannot meet the current needs. Therefore, it is necessary to continuously improve the parameters such as high temperature and high pressure of water vapor to improve the cycle efficiency, and at the same time bring higher performance to the steel. requirements. Due to the special physical properties of supercritical carbon dioxide, it has the advantages of smaller power generation system and floor space compared with water vapor, and because its energy density is higher than that of water, according to the existing high temperature resistance level of steel, the efficiency of supercritic...

AI Technical Summary

Problems solved by technology

[0008] The present invention overcomes the deficiency of insufficient denitrification degree caused by high temperature of supercritical carbon dioxide coal-fired boilers. The three-stage ammonia injection denitrification process realizes deep graded denitrification in the furnace, and the recirculation combustion of low-temperature flue gas effectively reduces the temperature in the furnace, reduces the generation of thermal NOx, and realizes Deep denitrification of supercritical carbon dioxide coal-fired boiler

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