Performance Study on Coal Gasification by High Temperature Air

A kinetics model and an experimental rig for high temperature air coal gasification (HTAG) research were set up. The effects of important operation parameters, such as air temperature and air/coal ratio, on gasification indexes were studied through the kinetics model and gasifier. The results show that: the model can accurately predict the gas composition. And when air temperature increases from 823K to 1073K, carbon conversion increases from 82% to 95%, gasification efficiency increases from 71% to 83%, calorific value and yield of the syngas increase from 7052kJ/m³ and 2.56m³/kg to 7586kJ/m³ and 2.79m³/kg respectively. With air/coal ratio increasing from 1m³/kg to 1.25m³/kg, the syngas yield increases from 2.27m³/kg to 2.82m³/kg, carbon conversion increases from 73% to 94% and gasification efficiency increases from 68% to 82%, but the calorific value changes little. When air/coal ratio is larger than 1.25m³/kg, the combustion zone extends much because of the excessive air and as a result, the calorific value and gasification efficiency decrease a lot. Thus the proper air/coal ratio should be 1.25m³/kg.