Adaptability of Wood Biomass to Fixed Bed Gasifier Controlling Bed Height

Abstract

For the biomass-to-liquid (BTL) process, pressurized gasification is an option in order to produce synthesis gas. Fixed bed gasification is promising as it results in relatively high conversion efficiencies as compared to other types of gasifiers on a smaller scale. Wood chips are adaptable feedstock for updraft fixed bed gasifiers. In considering whether to use waste materials or the use of powders for gasifiers, adaptability of the feedstock is a concern. For this study, a pressurized updraft fixed bed gasifier was chosen. The experimental setup comprised the gasifier, feedstock hopper, feeder, etc. inside a pressure vessel. Palm kernel shells (PKS) and wood pellets were used as feedstocks in this study. Although PKS is as adaptable feedstock as wood chips for updraft gasifiers, the adaptability of wood pellets, which are a kind of briquette biomass, has not been confirmed. As a result, good gasification was achieved with PKS, whereas problems such as channeling of the gas flow were caused using wood pellets. Such problems were reduced by lowering the bed height of the materials inside the gasifier, which increased the outlet gas temperature.