Table 3.

The solution of problems of operation with BFB.

BFB was found unsuitable for coal combustion, but it can be used for biomass and organic waste:

1)Erosion on in-bed heat-transfer tubes → volatiles burn in the freeboard, and this removes some of the heat release from the bed. Then the bed's heat balance can be closed at a reasonable bed temperature without tubes in the bed.

2)Unfavourable sulphur capture and low combustion efficiency → With biomass no sulphur capture is needed. The small fraction of char from biomass is quite reactive and yields a high combustion efficiency.

3)Unfavourable scale-up → The scale-up problem is avoided because transport to the plant is restricted in the case of biomass by its low energy density, J/m3 fuel.