Catalytic hydrothermal reaction of biomass and its application in blast furnace injection: Physicochemical, conversion mechanism, combustion behavior

This study employs a combination of experimental research and computational fluid dynamics (CFD) simulation to evaluate the optimal conditions for catalytic hydrothermal carbonization suitable for blast furnace injection. Through FTIR spectroscopy, Raman spectroscopy, ICP analysis, and combustion kinetics analysis, the physical and chemical properties of the hydrochar were determined. Subsequently, these properties along with kinetic parameters were applied to an improved CFD model to compare the flow patterns and combustion performance of hydrochar with PCI coal in blast furnaces. The results indicate that the optimal HTC conditions are identified at 300 degrees C with FeCl3 catalysis, yielding hydrochar (HTC-300-FeCl3) characterized by a calorific value of 32.10 MJ/kg, 98 % K element removal, and enhanced carbonaceous structure ordering. This is attributed to the addition of FeCl3 effectively enhances the generation of hydroxyl radicals in the aqueous phase and promotes deoxygenation and hydrogenation reactions in the solid phase, improving the quality of hydrochars. In addition, CFD model shows that the HTC-300 FeCl3 exhibits a higher burnout (86.2 %) and average gas temperature (2383.1 K) compared to PCI coal, indicating its greater potential as a PCI coal substitute in BF injection.