Pollutant Emission and Ash Accumulation Characteristics of Tri-Combustion of Coal, Biomass, and Oil Sludge

To study the ash accumulation and pollutant emission characteristics of tri-combustion of coal, biomass, and oil sludge, a fluidized bed and settling furnace system is established for tri-combustion experiments. The effect of blending ratio (the ratio of biomass and oil sludge range from 30% to 50% and 10% to 20%, respectively) and biomass types are examined. The results show that HTB, coal, and oil sludge reach peak NO and NO2 production at approximately 100 s and 200 s of combustion, respectively, with NOx levels returning to zero around 300 s. SO2 peaks around 100 s and then gradually declines. The blending ratio of HTB:oil sludge:coal at 50%:10%:40% demonstrates the most effective control over NOx and SO2 emissions, reducing NO, NO2, and SO2 production by approximately 33%, 20%, and 50%, respectively. In the ash with a ratio of Hutubi (HTB) + 50% oil sludge, the mass fractions of O, Si, Ca, Al, and Fe are approximately 27%, 23%, 20%, 8%, and 12%, respectively. With the increase in the blending ratio of biomass and oil sludge, the mass fraction of Si in the ash rises, while those of Ca, Al, and Fe decrease.