Co-combustion of coal and composite board sawdust: combustion behaviors, ash slagging characteristics, and gaseous pollutant emissions and control

Co-combustion of coal and biomass can achieve efficient and clean utilization of energy. This study investigated the combustion behaviors, gaseous pollutants (HCl, NO, SO2) emissions and coordinated control, and ash slagging characteristics of coal and CS using thermogravimetric analyzer, flue gas analyzer, and ash melting point test experiments. The results showed that the addition of CS decreased the ignition and final temperatures of coal, and the comprehensive combustibility index (CCI) increased linearly with increasing CS content. As the blending ratio of CS increased from 10 to 70%, the conversion rates of NO and SO2 decreased by 36.4% and 42.8%, respectively, but the conversion rate of HCl increased by 66.2%. When the combustion temperature increased from 750 to 950 degrees C, the conversion rate of HCl and SO2 increased from 63.1 to 70.1% and 28.7 to 41.3%, respectively. On the contrary, the NO conversion rate showed a slight downward trend with increasing temperature. The additives of Ca(OH)(2), CaO, Mg(OH)(2), MgO, and CaSiO3 all inhibited the emissions of gaseous pollutants, among which Ca(OH)(2) and CaO had the best effect. The slagging characteristics of the coal would be worse after mixing with CS. However, when the proportion of CS was less than 20%, the slagging characteristics of the mixtures were close to that of coal. Moreover, co-combustion of coal and CS had a synergistic effect on combustion performances and pollutant emissions.