Investigation of Coal Gangue on Mitigating Slagging of Wheat Straw

The effect of adding coal gangue (CG) under different ratios, temperatures and atmospheres on the slagging of wheat straw (WS) combustion was studied in a tubular furnace. At 800°C, there was obvious agglomeration and melting on the ash surface, caused by the reaction of alkali metal elements and alkali earth metal elements with SiO₂ to form low melting point silicate substance, resulted in serious slagging. After adding CG, Al₂O₃ in CG reacted with SiO₂ to form high melting point silicate minerals, which reduced the tendency of biomass slagging. According to the slagging discriminant results of empirical index, sample with 20% CG added combustion in air atmosphere has the lowest slagging tendency. The FactSage results showed that after adding CG, in the whole temperature range, there was no significant difference between the O₂/CO₂ atmosphere and the air atmosphere, but the phase contents were different.