A novel supercritical carbon dioxide combined cycle fueled by biomass: Thermodynamic assessment

Abstract

As a carbon-neutral type of renewable energy, biomass is beneficial for reducing carbon emissions in the electricity sector. A biomass gasification process integrated with a combined cycle is proposed here. Wood is chosen as the fuel and air as the gasifying agent. A supercritical carbon dioxide (SCO2) power cycle with recompression is selected for the recovery of waste heat from the combustion chamber. The net power output is considered to be 1 MW for the combined cycle in the investigation of component ratings and biomass feed rate. For a comprehensive thermodynamic analysis of this combined cycle, we examine three key parameters: gas turbine inlet temperature (1200–1400 K), topping cycle pressure ratio (5-10) and CO2 turbine inlet temperature (600–700 K). The maximum energy efficiency is achieved for the system at a specific pressure ratio and CO2 turbine inlet temperature. The energy efficiency rises with gas turbine inlet temperature, which reduces biomass consumption (at a fixed net power output). The CO2 emission rate to the environment is examined for various parameters; it is observed to decrease as biomass consumption decreases and to take on a value of 0.254 kg/s at an optimized state.