The dual bed gasification technology, invented in Austria, is a very successful one, not only in Austria but also in abroad. Based on this technology, the gasification facilities in Sweden, France, Thailand and Germany were built. An overview on dual fluidized bed or fast internal circulating fluidized beds (FICFB) is given in the following table.


The basic idea of the FICFB concept was to divide the fluidised bed into two zones, a gasification zone and a combustion zone. This technology is called double fluidized bed technology.

Between two zones a circulation loop of bed material was created, anyway the gases remained separated. The circulating bed material acted as heat carrier from the combustion to the gasification zone. The fuel was fed into the gasification zone and gasified with steam. The gas produced in this zone was therefore nearly free of nitrogen. The bed material, together with some charcoal, circulated to the combustion zone. This zone was fluidised with air and the charcoal was burned. The exothermic reaction in the combustion zone provided the thermal energy for the endothermic gasification with steam. With this concept, it is possible to get a high-grade product gas without the use of pure oxygen.