Advanced computational fluid dynamics simulation of coffee skin gasification in a multi‐stage downdraft reactor: Optimizing synthetic gas production for renewable energy applications

Abstract This research endeavours to simulate the operational conditions within a multi‐stage downdraft reactor fuelled by coffee skins. The objective of this study was to evaluate the impact of variations in the air–fuel ratio (AFR) and equivalence ratio (ER) on the operational efficacy of multi‐stage downdraft gasification reactors fuelled by coffee skins with respect to parameters such as temperature distribution, pressure, velocity, and gas composition. The simulation results indicate that augmenting the AFR and ER exerts a substantial influence on the distribution of temperature, pressure, and gas composition within the reactor. Optimal operating conditions were identified at an AFR of 1.03 and ER of 2.5, resulting in the generation of synthetic gas with a CO content of 23.5%, CH 4 of 2.9%, H 2 of 4.8%, and the highest lower heating value (LHV) of 4.52 (MJ/m 3 ). These findings highlight the potential of coffee skin gasification in producing high‐quality synthetic gas, which could serve as a renewable energy source for power generation and industrial applications, reducing dependency on fossil fuels while addressing agricultural waste management challenges.