The Utilization of Fixed Bed Coal Gasification By-Products to Produce Combustible Gas by Auto-thermal Process

Fixed bed gasification of coal produce some by-products, such as tar and coal powder. Coal powder obtained because the coal feed for fixed bed gasification reactor must have a size above 20mm, meanwhile, tar is a high molecular weight hydrocarbon compounds that will condense at low temperatures, which cause clogging and blocking of pipes. In this study, experiment on combustible gas generation from co-gasification of tar and coal powder was conducted in an auto-thermal reactor to determine the temperature of the process, combustible gas composition, and efficiency of the process, lower heating value. From calculation and experiments about oxidizing reactor operation, 20 kg/hr of tar was more promising to operate and can reach the optimal temperature which was 1900ºC. The energy from oxidizing reactor used for the reduction reaction of tar and pyrolysis of coal powder and produce combustible yield gas. The coal powder that can be conversion was about 14.4 kg/hr and produce approximately 84.52 kg/hr combustible gas. The calorific value of combustible yield gas amounted to 783.62 Cal/g. Combustible yield gas has advantages levels of hydrogen gas (H2) as high as 19.2%, which is already exceeding the levels of hydrogen gas from coal gasification is only <10%. Cold gas efficiency (CGE) has a value which was still low at 26.31%. It is caused by two factors, namely the calorific value fuel gas produced was still low and the remainder of the conversion of coal powder were still mostly in the form of charcoal.