Fundamental Fluid-Dynamic Investigations in a Scaled Cold Model for Biomass Steam-Gasification

The hydrodynamic behaviour of a one-fifth scale cold model of a 500 kW^th pilot plant has been studied. The plant is based on the circulating fluidized bed (CFB) principle and consists of a bubbling bed steam gasifier and a riser combustor. It is designed to produce a hydrogen-rich gas to be fed to a fuel cell for electricity generation. The cold model was constructed on the basis of established fluid-bed scaling laws and was built of perspex to enable the bed behaviour to be observed directly. Solids circulation rates and gas cross-flow between combustor and riser were investigated. A novel scaling parameter believed to be generally applicable to flow in risers was developed on the basis of these experiments.