Combustion Air Humidification for NOx Emissions Reduction in Gas Boiler

Combustion Air Humidification for NOx Emissions Reduction in Gas Boiler: An Experimental Study

Zhang, Qunli (Beijing University of Civil Engineering & Architecture; Collaborative Innovation Center of Energy Conservation & Emission Reduction and Sustainable Urban-Rural Development, Beijing)
Zhao, Wenqiang (Beijing University of Civil Engineering & Architecture; Collaborative Innovation Center of Energy Conservation & Emission Reduction and Sustainable Urban-Rural Development, Beijing)
Sun, Donghan (Beijing University of Civil Engineering & Architecture; Collaborative Innovation Center of Energy Conservation & Emission Reduction and Sustainable Urban-Rural Development, Beijing)
Meng, Xiangzhao (Xi’an Jiaotong University)
Hooman, K. (TU Delft Process and Energy)
Yang, Xiaohu (Xi’an Jiaotong University)

Process and Energy

2023

NO_x emission reduction from gas boilers has become a key issue in improving air quality. Combustion air humidification technology is gradually being used to reduce NO_x emissions. However, the NO_x emission reduction effect of gas boilers at a higher combustion air humidity has been studied less. A flue gas with low NO_x emissions and a waste heat recovery system using combustion air humidification technology are proposed in this study. In the ultra-low NO_x mode, the effect of high combustion air humidity on NO_x emission reduction and efficiency of the gas boiler were studied experimentally. In the waste heat recovery mode, the effects of the heat network backwater temperature on the NO_x emission reduction and system efficiency were studied experimentally. Results showed that an increase in air humidity can significantly reduce the NO_x concentration formed by combustion. The ultra-low NO_x mode reduces NO_x emissions from 130 mg/m³ to 23.3 mg/m³ and affects the boiler efficiency slightly. In the waste heat recovery mode, NO_x emissions can be reduced to 39.9 mg/m³ when the backwater temperature of the heat network is 55 °C. This condition improves the efficiency to 93.8%. The analysis results provide suggestions for the selection of the operation modes.

http://resolver.tudelft.nl/uuid:16c38df9-5825-4c85-a8e2-72f20bcce72f

https://doi.org/10.1080/01457632.2023.2171814

2023-08-01

0145-7632

Heat Transfer Engineering, 45 (1), 55-68

Green Open Access added to TU Delft Institutional Repository 'You share, we take care!' - Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

Institutional Repository

journal article

© 2023 Qunli Zhang, Wenqiang Zhao, Donghan Sun, Xiangzhao Meng, K. Hooman, Xiaohu Yang