DEMINERALIZATION OF BRAZILIAN COALS FOR USE IN GASIFICATION AND OXY-FUEL COMBUSTION PROCESSES, AIMING TO REDUCE CO2 EMISSIONS

Mineral matter in coal has an environmentally negative effect, as it is responsible for the generation of soot and slag. Technically, the mineral matter causes corrosion of equipment and reduces the combustion rate of coal, as well as influencing the sizing of equipment. Therefore, removal of this unwanted portion of the carbon matrix would reduce the need for importing high-quality coals and minimize transportation costs. This work aims to study the effects of the removal of mineral matter on the structure of southern Brazilian coal at the temperature of gasification and considering the kinetic parameters of the oxy-fuel combustion reaction. The demineralization process was conducted using solutions of HF, HCl, and HNO3 with concentrations of 20% (v/v). The samples were characterized by elemental analysis, proximate analysis, SEM, FT-IR spectroscopy, petrographic analysis, XRD, and XRF. The removal of the mineral portion introduced major changes in the structure of coal, reflecting an increase in the sta...