Experimental evaluation of wood and grass pellets in a bubbling fluidized bed gasifier

Abstract

Biomass gasification is an attractive technology capable of producing a versatile product gas that can be used for heat and power production as well as used as a feedstock for biofuels and higher-value chemicals synthesis. A fluidized bed gasifier is one of the better choices for an industrial scale operation. However, the specification and performance of different feedstocks must be characterized to use in a specific application with acceptable efficiency. In this article, the authors took two different feedstocks (i.e., wood and grass pellets) for the experimental characterization in a 20-kW pilot-scale bubbling fluidized bed gasifier. Equivalence ratio was varied between 0.1 to 0.2 for the grass pellets and 0.214 to 0.371 for the wood pellets. Frequent agglomerations were observed during the experiment with the grass pellets at a temperature of 800 °C and above. The carbon conversion for the gasification of grass pellets was observed to be lower compared to the gasification of wood pellets. Gasification of wood pellets gave a carbon conversion of around 60% at a temperature of around 850 °C.

Keywords

• Biomass gasification
• Bubbling fluidized bed
• Equivalence ratio
• Wood pellets
• Grass pellets