Steam generation unit in a simple version of biomass based small cogeneration unit

Abstract

The organic Rankine cycle (ORC) is a very promising process for the conversion of low or medium temperature heat to electricity in small and micro scale biomass powered systems. Classic ORC is analogous to Clausius-Rankine cycle in a steam power plant, but instead of water it uses low boiling, organic working fluids. Seeking energy and economical optimization of biomass-based ORC systems, we have proposed some modifications e.g. in low boiling fluid circuit construction. Due to the fact that the operation of a micro steam turbine is rather inefficient from the technical and economic point of view, a specially modified air compressor can be used as a steam piston engine. Such engine should be designed to work at low pressure of the working medium. Studies regarding the first version of the prototype installation were focused on the confirmation of applicability of a straw boiler in the prototype ORC power system. The results of the previous studies and the studies described in the paper (on the new cogeneration unit) confirmed the high potential of the developed solution. Of course, many further studies have to be carried out.