Influence of combustion air humidification on low nitrogen combustion performance of gas boiler
To reduce the concentration of NOx emissions from gas boilers,the use of humidified air as combustion air was explored to achieve nitrogen reduction.This study focused on simulating and experimentally investigating this approach's combustion process and efficacy.Different levels of humidity in the combustion air were studied to assess their impact on flue gas temperature and NOx emission mass concentrations.The results show that humidified air can notably lower the average NOx emission mass concentration at the furnace exit.When the humidity in the secondary air is increased to 76.90 g/kg,NOx emission mass concentration from the gas boiler can be reduced to 38.05 mg/m3,achieving a high nitrogen reduction efficiency of 71.96％.However,when the humidity in the air exceeds 57.30 g/kg,the rate of increase in CO mass concentration at the furnace exit rises sharply,leading to decreased combustion stability.Continuously elevating the water vapor content in the humidified air is unfavorable for the stable operation of the gas boiler.The introduced humidified air approach provides valuable technical insight for the nitrogen reduction retrofit of existing gas boilers.
gas boilercombustion air humidificationNOx emissions reductionnumerical simulationcombustion characteristics
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