Study on Combustion Characteristic of Coal-Char in Oxygen-Enriched Environments

Oxygen-enriched (O
₂
/CO
₂
) combustion in circulating fluidized bed(CFB) is one of the most promising clean coal combustion technology which shows good gaseous pollutants control, especially greenhouse CO
₂
. In the paper, the thermogravimetric experiments of Hennan lean coal-char under O
₂
/CO
₂
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
/CO
₂
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.