Effect of high-temperature and microwave expanding modification on reactivity of coal char for char-NO interaction

作者：Leng, Hao; Feng, Dongdong^*; Gao, Jianmin; Zhang, Yu; Zhao, Yijun; Du, Qian; Chang, Guozhang; Guo, Qingjie; Wang, Xin; Sun, Shaozeng

来源：Science of the Total Environment, 2021, 760: 144028.

DOI：10.1016/j.scitotenv.2020.144028

• Char
• High-temperature
• Microwave
• Expanding modification
• Char-NO interaction

Coal-fired industrial boiler has become a large source of atmospheric pollutants in China, urging to achieve low NOx emissions. This paper adjusts the coal char structure with high-temperature/microwave expanding modification to investigate the char-NO interaction. The results show that after high-temperature or microwave expansion, the pore structure of char is further expanded with more new pore structure of 2-12 nm. The proper expansion temperature/power/treatment-time increases the ablation collapse of char pores and the order of carbon structure. With microwave, C-O-C and C=O bands break, forming a large amount of aromatic C=C unsaturated carbon atoms, incrseasing the surface active sites of char-NO interaction. The optimum modifications of char-NO reactivity are 800 degrees C-90 s and 960 W-90 s. The reduction rate of NO by microwave modified char decreases with increase of inlet NO (<1200 ppm), and increases with increase of inlet CO (<8000 ppm). Burnout time of microwave modified char is shortened, with more rapid release of NO and larger conversion rate of char-N to NO. With microwave field, the conversion rate of char-N to NO at 900 degrees C is more significant than that at 600 degrees C. The too large microwave power cannot further shorten the char burnout time and the release time of NO.

• 单位
  宁夏大学; harbin inst technol