Investigation on Pulverized Coal Char Oxy-Combustion Behavior at Moderate and High Temperatures: Experiments and a Novel Developed Kinetics Modeling

2018-08-08T00:00:00Z (GMT) by Jingzhang Liu Baihang Li Jianguo Zhu
In oxyfuel combustion with temperature higher than ash flowing temperature (FT), both chemical interactions between the char gasification reaction with carbon dioxide, that is, C+CO<sub>2</sub> → 2CO, and the char oxidation reaction with oxygen, that is, C + (2-f)/2O<sub>2</sub> → fCO + (1-f)­CO<sub>2</sub>, are needed for further investigation. Both experiments and a novel developed kinetics model compared with three previous kinetics models are implemented to investigate oxy- and air-char combustion behaviors. Results show that in high temperature the maximum burning rate ratio as 34.8% from gasification is smaller than that as 47.1% in moderate temperature for inner pore reduction induced by ash mineral melting. The char mean consumption rate of sole gasification with carbon dioxide in 1773 K is 1.25 times to that in 1273 K, but this burning rate under 27%O<sub>2</sub>/CO<sub>2</sub> is 0.69 times to that in 1273 K. The mean burning rate ratio of char gasification increases from 28.0% to 40.0% in 1273 K and 1773 K, respectively.