Integrated pyrolysis regenerated plant (IPRP): An efficient and scalable concept for gas turbine based energy conversion from biomass and waste

A massive effort towards sustainability is necessary to prevent global warming and energy sources impoverishment: both biomass and waste to energy conversion may represent key actions to reach this goal. At the present, state of the art available technologies for biomass and waste to energy conversion are similar and include low to mid efficiency grate incineration or fluidized bed combustion with steam power cycles or mid to high efficiency gas turbine based cycles through integrated gasification technology. Nevertheless, these plants are all available from mid-to-high scale range that can be highly intrusive on protected areas and socially unacceptable. This paper proposes an innovative, low cost, high efficiency plant in which the residue is gasified in the absence of oxygen (pyrolysis), in a rotary kiln, by means of a highly regenerative gas turbine based cycle. Pyrolysis is preferred to gasification, because the syngas obtained has a higher low heating value and produces char or tar as a by-product with an interesting energy content to be re-utilized inside the cycle. Different plant configurations are proposed and discussed through principal thermodynamic variables parametric analysis. Results show that very interesting efficiencies are obtainable in the 30-40% range for every plant scale. This fact shows how IPRP technology can provide an interesting alternative to traditional technologies, especially for the small size (below 5MW). Moreover the IPRP technology provides a unique solution for microscale (below 500 kW) power plants, opening a new and competitive possibility for distributed biomass or waste to energy conversion systems where low environmental and social impact turns into higher interest and positive dissemination effect.