Numerical study of a downdraft gasifier to produce syngas

This study presents a numerical modeling of a downdraft gasifier. Wood (biomass) was considered as a feedstock for gasification as it is a cheap biomass and locally available. The numerical study was carried out to predict the flow behavior, the performance of the downdraft gasifier and the syngas composition precisely. The current downdraft gasifier was modeled using standard k–ε turbulence model, DPM for discrete phase, nonpremixed combustion model for combustion and DO radiation model for radiation modeling. The flow behavior and the temperature distribution of the downdraft wood gasifier were addressed which helped to understand the internal combustion phenomenon. Results also showed that the predicted syngas compositions were as follows: Nitrogen-54.12%, Hydrogen-8.10%, Carbon Monoxide-16.04%, Carbon Dioxide-13.01%, Methane-2.35%, Water vapor-05.10% by volume. In addition gasifier, thermal efficiency was found about 72%. This gasification process produces syngas which is directly usable as an alternative fuel to various IC engines.