Feasibility study of blast furnace injection of anthracite, bituminous coal and household waste: physicochemical characterization, combustibility and kinetic modeling

Eggshells, a by-product of the food industry, represent a significant yet often overlooked waste stream. Given their vast production volume and inherent properties, eggshells have the potential to serve as a sustainable and environmentally friendly co-fuel. Aiming to explore the co-combustion characteristics and kinetics of pulverized coal blended with eggshells and offer insights into their combined use as a renewable energy source, a systematic investigation was conducted to evaluate the physical and chemical properties of Shangwan bituminous coal, Shouyang anthracite coal, eggshell (ES) and their blends. Additionally, comprehensive experimental analyses were performed at different heating rates applying a non-isothermal thermogravimetric method. The findings revealed that the addition of ES enhanced the combustion efficiency. The combustion characteristics were significantly influenced by the ES content, with an optimal blend ratio identified for maximum combustion efficiency. To represent the thermal degradation experiments, random pore model and volume model were employed. Furthermore, activation energies and pre-exponential factors were determined. The random pore model demonstrated more superior performance compared to the volume model. The activation energies of all the samples ranged between 18.29 and 42.48 kJ/mol, with the lowest value observed for the sample containing 20 mass% ES.