The section Thermal Power Engineering of the Delft University of Technology is operating a rig that is used for research on pressurised fluidised bed gasification. This rig has been used for about 9 years to conduct combustion experiments and was extensively modified during 1995 to enable gasification experiments using coal, biomass and coal-biomass mixtures as fuels and air and air-steam mixtures as the fluidisation/ gasification medium. The installation has a maximum thermal capacity of 1.5 MWth and can operate at pressures up to 10 bar and temperatures of 900 degrees Celsius. Alstom Gas Turbines Ltd has designed manufactured and supplied a pressurised, high temperature combustor for the biomass derived, LCV, fuel gas matched to the Delft gasifier. The combustor has been installed in the Delft test rig and experiments have been carried out to gather experimental data on the steady state and dynamic behaviour of the combustor. The experimental results have been compared with the simulation results obtained from the mathematical models describing the steady state and dynamic behaviour of the combustor and used to refine and validate these models. A mathematical model which simulates the steady state behaviour of the combustor has been developed by Delft University of Technology in collaboration with Fluent Europe Ltd. The experimental results obtained in the Delft test rig were used to refine and validate the model. A mathematical model which simulates the dynamic behaviour of the combustor has been developed by Alstom Gas Turbines Ltd. The experimental results obtained from the Delft test rig were used to refine and validate the model using empirical relationships where no theory has been developed. The refined and validated steady state and dynamic combustor models have been used by Alstom Gas Turbines Ltd to develop a gas turbine model which is incorporated in a plant layout for an advanced biomass-fuelled IGCC plant. The plant layout is developed by Delft University of Technology and Alstom Gas Turbines Ltd and has been used for the simulation of the steady state and dynamic behaviour of the system.