An Externally Fired Micro Combined-Cycle, with Largely Adjustable Steam Turbine, in a CHP System

This work stems from the idea of demonstrating the feasibility of using micro combined plants for the simultaneous generation of electrical and thermal energy, by external combustion of low quality fuels. In particular, this study is aimed at acquiring the knowledge necessary for the development of a small power plant consisting of a micro gas turbine and an innovative steam micro-turbine. The topping cycle is carried out with a micro gas turbine coupled with a heat exchanger and an external combustor, in which biomass is burned. For the bottoming cycle an impulse turbine has been adopted, characterized by a variable section nozzle, capable of expanding widely variable steam flow rates, with small efficiency losses. For the purpose of an immediate display of proportions, dimensions and assembly possibilities, 3D printing of a turbine scale model was also made.