Low-nitrogen combustion system and method for double-U-shaped liquid slagging boiler containing staged furnace smoke

Abstract

The invention belongs to the technical field of coal-fired power generation, and discloses a low-nitrogen combustion system and method for a double-U-shaped liquid slagging boiler containing staged furnace smoke. The system comprises a first assembly and a second assembly which are connected with two combustion chambers of the double-U-shaped liquid slagging boiler respectively, and the first assembly and the second assembly both comprise air-pulverized coal combustion systems and furnace smoke systems. Each air-pulverized coal combustion system comprises a hot air pipeline, a pulverized coalcombustor and a pulverized coal pipeline. Each furnace smoke system comprises a furnace smoke nozzle, a furnace smoke pipeline and a furnace smoke fan. One end of each furnace smoke pipeline is connected with an outlet of the corresponding furnace smoke fan, and a first furnace smoke branch and a second furnace smoke branch are arranged at the other end of each furnace smoke pipeline. The first furnace smoke branches are connected with the pulverized coal pipelines, the second furnace smoke branches are connected with the combustion chambers of the double-U-shaped liquid slagging boiler by connecting the furnace smoke nozzles, and inlets of the furnace smoke fans are connected with the double-U-shaped liquid slagging boiler. The extracted furnace smoke is divided into two stages and is fedinto the combustion chambers from the pulverized coal combustor nozzles of the pulverized coal pipelines and independent furnace smoke nozzles, so that the amount of NOx generated by combustion is effectively reduced.

Description

technical field [0001] The invention belongs to the technical field of coal-fired power generation, and relates to a low-nitrogen combustion system and method for a double U-shaped liquid slagging boiler containing classified furnace smoke. Background technique [0002] The low-nitrogen combustion of the double U-shaped liquid slagging boiler is limited by the small size of the boiler, and the "U"-shaped combustion method is adopted. The combustion process in the furnace is carried out under high temperature and high environment to facilitate the formation of liquid slagging, which is different from the common The low-nitrogen combustion of tangential and hedging boilers requires combustion under low-temperature and low-oxygen conditions, which is contrary to the control requirements for low NOx formation. [0003] Therefore, the amount of NOx generated at the furnace outlet of the current double U-shaped liquid slagging boiler is generally high, which is very unfavorable fo...

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Problems solved by technology

[0003] Therefore, the amount of NOx generated at the furnace outlet of the double U-shaped liquid slagging boiler is generally high, which is very unfavorable for the ultra-low emission target of the boiler. An effective way to reduce the NOx concentration at the furnace outlet is urgently needed

[0004] At present, some boilers use the combustion technology with flue gas recirculation to reduce the amount of NOx generated during the combustion process. Although there have been corresponding researches on tangential and hedging boilers, these researches are mainly based on single-stage Furnace smoke exists in the form of double U-shaped liquid slag discharge boilers, because the complexity of the boiler body and combustion system is significantly higher than that of conventional boilers. NOx formation is generally high

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