Bed Material Selection for 100kw Dual Fluidised Bed Gasifier: Effects on Gasifier Operation and Producer Gas Quality

Selections of commonly available minerals were trialled in a 100kW fast internally circulating fluidised bed (FICFB) gasifier at the University of Canterbury in New Zealand, for the purposes of improving producer gas composition and reducing tar yield. Operational parameters were recorded during several runs and the compositions of producer gas, flue gas, and tar exiting the gasifier were measured. Using the results of previous runs with inert greywacke sand bed material as a basis, the effects of fluidising with different bed materials were analysed. Variations in tar composition were noted for bed materials containing olivine sand, and adding calcite to the bed material was shown to increase hydrogen content in producer gas and to increase the gasification efficiency. Bed material properties such as attrition resistance and agglomeration potential were also examined with various operational conditions.