Conference Dates

May 22-27, 2016


This work, carried out in the GAYA project frame and subsidized by ADEME, concerns the hydrodynamic study of a 60 kWth circulating fluidized bed pilot plant constructed at the Laboratoire de Génie Chimique in Toulouse for biomass gasification. In that process, biomass gasification and heating of fluidisation material (sand, olivine, catalyst…) which also acts as heat transfer medium, are performed in two separate reactors: a dense fluidized bed and a transported bed. Thermal energy, required in order to heat the fluidisation material, is supplied by the partial combustion of the char produced in the gasification reactor. The hydrodynamic study carried out at atmospheric pressure between 20 °C and 900 °C leads to the determination of the influence of the temperature and media average particle size (olivine), the reactor geometric properties and the fluidization gas nature (air or steam) on the media hydrodynamic parameters such as the minimum fluidization velocity and porosity, the bed expansion and the solid transport velocity. Results have shown that the minimal fluidization and transport velocity decrease with the bed temperature increase. However, the bed expansion is not affected by this factor. Furthermore, the particles transport happens from the terminal falling velocity and increases with the gas velocity. The fluidization gas nature has a significant effect on the minimal fluidization velocity, but not on the bed expansion. Correlations are proposed in order to estimate the characteristic parameters of the olivine hydrodynamic behavior depending on the temperature, the fluidization gas nature and the solid particle size.