Small-Scale Single Stage Downdraft Biomass Gasifier with Shaking Grate Mechanism

Abstract

A new approach to improve the gasification process was studied through the development of an automatic shaking grate mechanism in a single stage downdraft gasifier. Tar and ash build-up are problems commonly encountered during the gasification process. This study was conducted to mechanically induce tar cracking, to prevent blockages of biomass materials at the hopper as well as to ease the removal of ashes during the gasification process. It applies the principle of increasing the effective area for tar cracking at elevated temperatures to improve the amount of combustible producer gas as well as the conditions for thermal tar cracking. Experiments were done at varying air flow rates to evaluate different gasification parameters in comparison to conventional downdraft gasifier. The study resulted to 74% reduction in tar content, 30% improvement in high heating value and 27% increase in efficiency compared to the conventional downdraft gasification at 160 Lpm air flow rate.