Analysis of Indirectly Fired Gas Turbine for Wet Biomass Fuels Based on commercial micro gas turbine data

The results of a study of a novel gas turbine configuration is being presented. In this power plant, an Indirectly Fired Gas Turbine (IFGT), is being fueled with very wet biomass. The exhaust gas is being used to dry the biomass, but instead of striving to recover as much as possible of the thermal energy, which has been the practice up to now, the low temperature exhaust gases after having served as drying agent, are lead out into the environment; a simple change of process integration that has a profound effect on the performance.

Four different cycles have been studied. These are the Simple IFGT fueled by dry biomass assuming negligible pressure loss in the heat exchanger and the combustion chamber, the IFGT fueled with wet biomass (Wet IFGT) assuming no pressure losses, and finally both the Simple and the Wet IFGT incorporating typical data for pressure losses of commercially available micro turbines.

The study shows that the novel configuration, in which an IFGT and a drying unit have been combined, has considerable merit, in that its performance exceeds that of the currently available methods converting wet biomass to electric power by a factor of five. The configuration also has clear advantages with respect to corrosion and to the environmental friendliness and the quantity of the waste products and their usefulness.