Co-utilization of two coal mine residues: Non-catalytic co-combustion of coal bed methane and coal gangue in a circulating fluidized bed

In this study, the experiments were carried out in a circulating fluidized bed with different coal bed methane and coal gangue mixing ratios. The results show that bed temperature distribution becomes well-proportioned and the combustion efficiency increases when coal bed methane was introduced. The NO emission increases along with the excess air coefficient rise. The SO2 emission reduces first and then increases with the rising bed temperature and there is an optimum temperature corresponding to the lowest SO2 emission. At the same time, the effects of the bed temperature and excess air coefficient on pollutant emissions are more obvious when coal bed methane and coal gangue mixing ratio is less than 0.3. In the experiments, the best operation conditions have been found at coal bed methane and coal gangue mixing ratio of 0.2 and excess air coefficient of less than 1.3. The results show that the co-combustion of coal bed methane and coal gangue in circulating fluidized bed is feasible and provides some references for the combustion optimization.