Z. Liu, T. Suda, M. Narukawa, M. Takafuji
IHI Corporation, Japan
pp. 172 - 175
Keywords: gasification, scale-up, carbon conversion, residence time distribution, fluidized bed, segregation
Gasification is a good method to upgrade solid fuel. The fluidized-bed gasifier is widely used for the gasification of low-rank coal and biomass. IHI develops a fluidized-bed gasifier TIGAR(Twin IHI GAsifieR). It is important to predict gasifier characteristics when enlarging existing facilities. For simplicity, we split the gasification process in bubbling fluidized beds into two processes, namely the movement of particles and the reaction of solid fuel. The movement of particles is described by the residence time distribution (RTD)in the continuous fluidized bed of the gasifier. RTD have been calculated by using a segregation-convection-diffusion model for lab scale, bench scale, pilot scale and commercial scale. The calculation have been validated by experiments with good agreement for lab and bench scales. The gasification reaction of the solid fuel is described by carbon conversion X(t) in a non-continuous fluidized bed with batch feeding (residence time is infinity). Experiments are made to measure X(t). It is assume that X(t) is independent of bed length. The carbon conversion for the continuous fluidized bed can be calculated by integration of RTD(t)X(t). The carbon conversions predicted by calculations and measured by experiments are compared. They agree well.