CARBON CONTENT OF CHAR IN FLUIDIZED-BED COAL GASIFIER

Coal gasification experiments for six kinds of coal under partial combustion with oxygen were conducted using a pressurized fluidized bed reactor of about 10cm diameter at temperatures of 1100 approximately 1400K and coal feed rates of 2 approximately 6kg/h. The feed coal particles were prepared large enough so as not to be entrained by freeboard gas. Analysis of carbon and ash mass balances shows that the carbon content of the fluidized bed is dependent on carbon conversion and has no relation to coal feed rate, gasification temperature and H2O feed rate. It is suggested that the fine char high in carbon content that is carried over by the gasification gas decreases the carbon conversion and is mainly produced during devolatization of coal. It is also suggested the production of fine char during gasification and combusion scarcely decreases carbon conversion. Under these conditions, maximum carbon conversion from 0.92 to 0.98 is attainable.