Optimization of Low-Grade Coal and Refuse-Derived Fuel Blends for Improved Co-Combustion Behavior in Coal-Fired Power Plants

Abstract

Abstract This study aims at utilizing three waste materials, i.e., Biomass-Solid Refuse Fuel (SRF), Tire Derived Fuel (TDF), and Sludge Derived Fuel (SDF), as ecofriendly alternatives to coal-only combustion in co-firing power plants. The contribution of waste materials is limited to ≤ 5% in the composition of the mixed fuel (coal + waste materials). Statistical experimental design and response surface methodology is employed to investigate the effect of mixed fuel composition (SRF, TDF, and SDF) on gross calorific value (GCV) and ash fusion temperature (AFT). A quadratic model is developed and statistically verified to apprehend mixed fuel constituents' individual and combined effects on GCV and AFT. Constrained optimization of fuel blend, i.e., GCV > 1250 kcal/kg and AFT > 1200°C, using the polynomial models projected the fuel-blend containing 95% coal with 3.84% SRF, 0.35% TDF, and 0.81% SDF. The observed GCV of 5307 kcal/kg and AFT of 1225°C for the optimized blend were within 1% of the model predicted values, thereby establishing the robustness of the models. Our findings can foster sustainable economic development and zero CO2 emission objectives by optimizing the utilization of waste materials without compromising on the GCV and AFT of mixed fuels in coal-fired power plants.