Performance optimization of a gas-steam combined power plant partially fed with syngas derived from pomace

In this paper a gas-steam combined-cycle, partially fueled by syngas (produced in an embedded downdraft gasifier fed with pomace), is considered. In addition, an auxiliary combustion system is directly fed by ligno-cellulosic biomass. The thermodynamic model of the entire system is developed by means of the Cycle-Tempo software. The gasification process is supposed to occur at ambient pressure and air is used as gasifying agent. An optimization process has been introduced by means of the Design of Experiment (DoE) technique. The design variables and their corresponding ranges have been chosen by using a heuristic criterion. The power plant performance is represented by the thermal efficiency, - ηI, the exergetic efficiency, ηII, the cost of electricity, COE, and the net return, Rnet. The DoE technique provided the so-called Pareto barrier, which isolates all the non-dominated solutions.