Fluid-Dynamic Investigations in a Scaled Cold Model for a Dual Fluidized Bed Biomass Steam Gasification Process: Solid Flux Measurements and Optimization of the Cyclone

Abstract

Gasification of biomass is an attractive technology for combined heat and power (CHP) production. A dual fluidized bed steam gasifier is in commercial operation at the biomass CHP plant in Guessing/Austria since 2002. For circulating fluidized bed applications the bed material consumption is economically crucial. Thus, cyclones for circulating fluidized beds need to be designed properly. Some erosion and caking in the cyclone of the gasifier could be observed with increasing hours of operation. The influences of these effects as well as the influence of the solid circulation rate between the two units on the separation efficiency were investigated by fluid-dynamic investigations using a scaled cold model. The results show that due to erosion and caking elutriation rates are increased, especially for smaller particles. However, the cyclone achieves fractional separation efficiencies of more than 99.9%.

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