Fluidized-bed co-gasification process of colombian coal and biomass wastes

Coffee husk, rice husk and sawdust are Colombian agroindustrial wastes which were mixed with fine coal from the Amaga region (Antioquia). In some regions in Colombia, fine coal from coal mining is considering as a waste. Fine coal has little demand in Colombia because the most of the coal firing systems are stokers. One alternative for using this fine coal is fluidized beds due to fine coal has high ash and sulfur content, co-gasification with biomass is an option to decrease sulfur emissions. Those mixtures were gasified using air and steam as gasifying agents. In this study, the air-mixture ratio and steam-air ratio effects over conversion, temperature and carbon monoxide concentration were analyzed. Air-material ratio and steam-air ratio were changed obtaining conversion values between 76% and 86% and bed temperatures between 750 °C and 950 °C. The highest conversion and temperature values were obtained during sawdust-coal gasification, while rice-coal mixture gasification showed the lowest carbon monoxide concentrations. Biomass-coal gasification showed better results than coal gasification.