Co-combustion of coal and biomass waste in pilot-scale for energy use

The use of biomass in co-combustion systems using fluidized bed technology is considered a viable alternative to reduce the emission of pollutants. The herein study presents an experimental analysis to determine the technical feasibility of using run-of-mine (ROM) coal and its waste combined with biomass in a combustor of bubbling fluidized bed in pilot scale. The proximate analysis, ultimate analysis, and heat values were performed to characterize the fuels, and the chemical composition of the gases was monitored. During the co-combustion tests, it was observed that a lower mass flow rate of fuel was needed for mixtures of coal and biomass to reach the operating temperature of the bed when compared to other fuels. The results of the chemical analysis showed that the unburned material was less than 1% in the bottom ashes and less than 7.3% in the fly ashes. For all the performed tests, a SO₂ removal efficiency of 75.8% was reached, and the results indicate that the gas can be used to generate other sulfur compounds. The combustion efficiency was found to be in the range of 91.8% and 96.6%, which demonstrates that co-combustion of coal, its wastes, and biomass is a promising option for heat generation.