ABSTRACT
Compared with fossil fuel, biomass is a clean energy with zero CO2 emission, because CO2 is fixed by photosynthesis during biomass growth and released again during utilization. Due to its low energy density, direct use of biomass is not convenient. Thus, it is necessary to convert biomass to fuel gas, such as hydrogen, which can be used cleanly and highly efficiently in fuel cell. Thermo-chemical gasification is likely to be the most cost-effective conversion process and it is promising technology for renewable hydrogen production by utilizing biomass. Biomass gasification produces a mixture of gases (mainly consisting of H2, CO, CO2, CH4 and higher hydrocarbons), solids (char) and liquids (aromatic hydrocarbons) known as ‘tars’. The relative proportion of each constituent depends on the operating conditions such as temperature, pressure, type of gasifying medium, biomass type; biomass feed rate, heating rate, flow rate of gasifying medium, physical characteristics of biomass such as particle size, shape, surface area to volume ratio and the gasifier design.
