Ammonia coal multi-stage preheating combustion method

Abstract

The invention discloses a multi-stage preheating combustion method for ammonia coal, which changes a one-time preheating mode of a traditional self-maintaining preheating combustor for pulverized coal into three-stage preheating, on one hand, the retention time of the pulverized coal in a high-temperature reduction area is prolonged, so that high-temperature gas-solid mixed fuel generated after mixing of ammonia coal contains a large amount of high-temperature combustible reducing gas, and the combustion efficiency is improved; not only is NO heterogeneous reduction promoted and generation of nitric oxide in the combustion process of the ammonia coal fuel inhibited, but also flame propagation speed is increased and flame stability is enhanced, so that the ignition performance of the ammonia coal fuel is relatively good; and on the other hand, heat released by combustion of combustible gas of the high-temperature gas-solid mixed fuel before reaction is increased, heat radiation between a flame area and an unburned area is enhanced, and the flame combustion flame of the ammonia-coal mixed fuel is further stable. Therefore, the ammonia coal multi-stage preheating combustion method has the advantages of being good in ignition performance, stable in flame, capable of effectively inhibiting generation of nitric oxide and the like.

Description

technical field [0001] The invention relates to the technical field of ammonia-coal combustion, in particular to a multi-stage preheating combustion method for ammonia-coal. Background technique [0002] As a zero-carbon fuel, ammonia gas can be used directly as fuel for coal-fired boilers, which can significantly reduce carbon dioxide emissions compared with traditional fossil fuels. Under the national dual-carbon target, ammonia as a hydrogen carrier is a new type of renewable zero-carbon fuel and one of the high-quality alternative fuels for pulverized coal boilers. However, the low reactivity and high nitrogen content of ammonia molecules lead to the problems of difficult ignition, stable combustion and high NOx emissions. Therefore, ammonia-coal co-firing is one of the effective technical paths for reducing carbon dioxide emissions from pulverized coal boilers. At present, pulverized coal combustion generally adopts self-sustaining preheating combustion. Self-sustainin...

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Problems solved by technology

However, the low reactivity and high nitrogen content of ammonia molecules cause it to face the problems of difficult fire, stable combustion and high NOx emissions. Therefore, co-combustion of ammonia and coal is one of the effective technical paths for pulverized coal boilers to reduce carbon dioxide emissions.

At present, self-sustaining preheating combustion is generally used in pulverized coal combustion. Self-sustaining preheating combustion refers to the design of two or more stable combustion mechanisms such as swirling flow, blunt body, and pre-combustion / preheating chamber before the pulverized coal enters the furnace for combustion. The combustion method promotes the return of high-temperature flue gas and realizes self-sustaining preheating combustion, but self-sustaining preheating combustion has problems such as poor combustion effect of ammonia coal

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