Dynamic modelling of biomass power plant using micro gas turbine

Biomass is becoming a more and more interesting option to replace conventional fossil fuels for heat and power generation. Small plants able to use solid biomass, collected in the plant neighbourhoods, are having a growing diffusion: University of Pisa jointly with some local manufactures has designed, built and tested an externally fired micro gas turbine (EFMGT) supplying 70 kW of electricity as well as 200-250 kW of useful heat. The present paper focuses on the development of a dynamic simulator of the plant. A mathematical model was implemented for the physical and chemical behaviour of the biomass combustion process, as well as for heat transfer mechanisms and turbine behaviour to assess the plant operating variables in both steady state and transient operating conditions. Comparison between model results and data gathered on a test plant shows a good matching (with deviation below 5%) of the main and most critical variables in a wide range of operating conditions which makes the model suitable for synthesize a closed-loop control system able to ensure the highest performances in power production.