Effect of temperature, oxygen concentration, and CaO addition on SO2 and NOx emissions during oxygen-fuel combustion of municipal sludge

• Published in: Journal of the Energy Institute Vol. 105; pp. 424 - 432
• Main Authors: Sun, Shaoyan, Xu, Donghai, Liang, Yu, Jiang, Guanyu, Diao, Yunfei, Gong, Xuehan, Wang, Bingsheng
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.12.2022
• Subjects: CaO; Municipal sludge; NOx emission; Oxygen-fuel combustion; SO2 emission; CaO; Municipal sludge; NOx emission; Oxygen-fuel combustion; SO2 emission
• ISSN: 1743-9671
• DOI: 10.1016/j.joei.2022.10.012

Oxygen-fuel combustion is an effective and promising method of steadily minimizing municipal sludge volume at the same time exploiting available heat and falling emissions. The effects of temperature, oxygen concentration, and CaO addition on SO2 and NOx emissions from municipal sludge combustion in CO2/O2 atmosphere were systematically explored via a lab-scale electrically heated tubular furnace in this work. The results show that the minimum average emissions of both SO2 and NOx were observed at 800 °C. Compared with air, all oxygen-fuel atmospheres reduced SO2 emission, and a salient effect was observed with 30% of oxygen concentration. In contrast, the inhibition of NOx emission was inconspicuous and exacerbated in some cases. With a lower oxygen concentration (21%), CaO evidently reduced SO2 emission and 8 wt% addition performed the best. The removal efficiency of NO by CaO addition was poor and only exhibited slight inhibition with 5 wt% addition. •SO2 and NOx emissions during oxygen-fuel combustion of municipal sludge were studied.•Effects of oxygen concentration on SO2 and NOx emissions were compared.•CaO evidently reduced SO2 emission with appropriate addition amount.•Optimal addition ratio of CaO for NO removal was obtained.