Study on combustion characteristic of coal-char in oxygen-enriched environments

Oxygen-enriched (O-2/CO2) combustion in circulating fluidized bed(CFB) is one of the most promosing clean coal combustion technology which shows good gaeous pollutants control, especially greenhouse CO2. In the paper, the thermogravimetric experiments of Hennan lean coal-char under O-2/CO2 and O-2/N-2 atmosphere have been carried out, the influence of atmosphere, O-2 concentration and heating rate on the combustion characteristic of coal-char being analysed. The results of the experiment show that O-2 concentration and heating rate have a great influence on the coal-char combustion characteristics in oxygen-enriched environment. The coal-char combustion characteristic ameliorates with increasing the O-2 concentration and improving the heating rate. Under the same O-2 concentration, the coal-char combustion characteristic in O-2/CO2 atmosphere is a little poorer than that in O-2/N-2 atmosphere. A reaction kinetic model for coal-char combustion in oxygen-enriched environment was also deduced and it agreed well with experimental data.