TY - JOUR
T1 - Experimental Research on Effects of Combustion Air Humidification on Energy and Environment Performance of a Gas Boiler
AU - Zhang, Qunli
AU - Li, Yanxin
AU - Zhang, Qiuyue
AU - Jiao, Yuqing
AU - Shi, Qiu
AU - Lu, Xiaoshu
N1 - Funding Information:
The Fundamental Research Funds for Beijing University of Civil Engineering and Architecture (BUCEA). The BUCEA Post Graduate Innovation Project (PG2022070 and DG2023010).
Publisher Copyright:
© 2024 American Society of Mechanical Engineers (ASME). All rights reserved.
PY - 2024/2/1
Y1 - 2024/2/1
N2 - To increase the waste heat recovery (WHR) efficiency of gas boiler and decrease NOx emissions, a flue gas total heat recovery (FGTHR) system integrating direct contact heat exchanger (DCHE) and combustion air humidification (CAH) is put forward. The experimental bench and technical and economic analysis models are set up to simulate and evaluate the WHR performance and NOx emissions in various operation situations. The results show that when the air humidity ratio elevates from 3 g/kgdry air to 60 g/kgdry air, the dew point temperature increases by 7.9 °C. When the flue gas temperature approaches the dew point temperature, the rate of improvement of the FGTHR system’s total heat efficiency notably rises. With spray water (SW) flowrate and temperature of 0.075 kg/s and 45 °C, the WHR efficiency relatively increases by up to 8.4%. The maximum sensible and latent heat can be recovered by 4468 w and 3774 w, respectively. The flue gas temperature can be reduced to 46.55 °C, and the average NOx concentration is 39.6 mg/m3. Compared with the non-humidified condition, the NOx and CO2 emissions relative reduction of the FGTHR system are 61.2% and 8.7%. The payback period of FGTHR system is 2 years. Through simulation, it can be concluded that the decrease in exhaust flue gas temperature and velocity, as well as the increase in exhaust flue gas humidity, has a negative impact on the diffusion of NOx in the atmosphere.
AB - To increase the waste heat recovery (WHR) efficiency of gas boiler and decrease NOx emissions, a flue gas total heat recovery (FGTHR) system integrating direct contact heat exchanger (DCHE) and combustion air humidification (CAH) is put forward. The experimental bench and technical and economic analysis models are set up to simulate and evaluate the WHR performance and NOx emissions in various operation situations. The results show that when the air humidity ratio elevates from 3 g/kgdry air to 60 g/kgdry air, the dew point temperature increases by 7.9 °C. When the flue gas temperature approaches the dew point temperature, the rate of improvement of the FGTHR system’s total heat efficiency notably rises. With spray water (SW) flowrate and temperature of 0.075 kg/s and 45 °C, the WHR efficiency relatively increases by up to 8.4%. The maximum sensible and latent heat can be recovered by 4468 w and 3774 w, respectively. The flue gas temperature can be reduced to 46.55 °C, and the average NOx concentration is 39.6 mg/m3. Compared with the non-humidified condition, the NOx and CO2 emissions relative reduction of the FGTHR system are 61.2% and 8.7%. The payback period of FGTHR system is 2 years. Through simulation, it can be concluded that the decrease in exhaust flue gas temperature and velocity, as well as the increase in exhaust flue gas humidity, has a negative impact on the diffusion of NOx in the atmosphere.
KW - air emissions from fossil fuel combustion
KW - energy conversion/systems
KW - energy systems analysis
KW - fuel combustion
KW - natural gas technology
UR - http://www.scopus.com/inward/record.url?scp=85180326158&partnerID=8YFLogxK
U2 - 10.1115/1.4063432
DO - 10.1115/1.4063432
M3 - Article
AN - SCOPUS:85180326158
SN - 0195-0738
VL - 146
JO - Journal of Energy Resources Technology, Transactions of the ASME
JF - Journal of Energy Resources Technology, Transactions of the ASME
IS - 2
M1 - 022304
ER -
