Performance of a Hybrid Power Generation System Using Biomass Gasification and Concentrated Solar Thermal Processes

Abstract

A hybrid power generation system using biomass gasification and concentrated solar thermal processes (CSTP) was proposed. We analysed the system performance of a combined cycle with a bubbling fluidized bed gasifier (BFG) using CO2-H2O-O2 mixture and CSTP using molten salt. BFG was simulated by a semi-kinetic model, applying a continuously stirred tank reactor (CSTR) model for the bed behaviour and a plug flow reactor (PFR) model for the freeboard reactions. Operating conditions of the plant and heat exchanger network were optimized separately. The current paper shows the effects of gasifying agents and heat input from CSTP on system efficiency among examined parameters. Pure steam at the molar ratio of steam to carbon in biomass around 0.5 was optimum gasifying agent in this system. By increasing heat input from CSTP, marginal efficiency of biomass-to-electricity was enhanced by 6.2-6.5% (from 39.9 ∼41.2% to 46.1∼47.5%).