It consists of two connected fluidised beds of which one is a combustion reactor that produces heat to the gasification reactor where the gas i produced. The efficiency has been reported to 70 percent.

To increase the efficiency, problems with the ash in the biomass have to be handled: deposit formation, corrosion, agglomeration of bed material and poisoning of catalysts. The purpose of the present project is to obtain new knowledge about the ash elements in the gasification process. Such knowledge is concentration and form of ash elements in the solid phase, the fraction in the gas phase, and the tendency of bed materials to accumulate ash elements.