A micro combined cycle plant for power generation from solid biomass: coupling EFMGT and ORC

The possibility to directly use solid biomass for electricity generation has several advantages compared with usual solutions which typically need large sizes and/or complex fuel processing treatments. University of Pisa, jointly with some local manufacturers, has designed, built and tested an externally fired micro gas turbine (EFMGT) supplying 75kW of electricity from the direct use of solid biomasses, as well as useful heat (200-250kW) for local thermal users. The plant is able to compete with other solutions and some units have been installed in industrial sites. Moreover the heat available would be enough for generating up to 30kW through an Organic Rankine Cycle system. The technical solution which has been investigated and is currently being installed in the test facility at the manufactured premises includes a smaller ORC system which will add some 15kW to the electricity generation with a reduction of the overall specific cost, as well as the electricity generation cost. The paper will present the details of the plant and will show the results of theoretical assessments and calculations of the performances of the ORC system alone and together with the EFMGT