Design and Preliminary Testing of a Bubbling Fluidized Bed Gasifier for Biomass Gasification

Biomass is widely considered to be a major potential fuel and renewable resource for the future. Gasification is a process that converts biomass into a gaseous mixture containing carbon monoxide and hydrogen etc. In addition to maintaining consistent fuel properties, gasifier design and its operation, the gas cleaning are key issues in the process chain. This paper describes the design and preliminary operation experience of a laboratory-scale bubbling fluidized bed gasifier which is designed for the gasification of willow chips with a gasification rate of 2.5 kg/hr. The gasification system mainly consists of a single screw feeding system, a bubbling fluidized bed reactor, a cyclone for primary removal of particles, a cooler and a downstream gas cleaning and combustion unit. Silica sand is used as the bed material and air is used as the gasification medium. At the initial stages, the performance of the biomass feeder and the fluidization quality with different size ranges of sand particles and addition of biomass material into the sand bed have been evaluated. Preliminary testing results are analysed and presented in this paper.