Thermodynamic Optimization of a Biomass-based Integrated Gasification Combined Cycle with Post Combustion Carbon Capture using Potassium Carbonate

Abstract

Abstract Biomass proved promising outcomes as a sustainable alternative to fossil fuels for energy generation. With the mounting concerns on the environment and the increasing pressures on natural resources, there is an impetus to investigate new biomass feedstocks and further develop efficient biomass conversion processes and technologies. Gasification, amongst other thermochemical conversion processes, is considered as one of the most efficient and clean processes, generating syngas which can be fed to gas turbines for electricity production. To enhance the process’ efficiency, the integrated gasification combined cycle is adopted which utilises the exhaust heat from the gas turbine to operate a joined steam turbine. In this study, a biomass based integrated gasification combined cycle (BIGCC) with CO 2 recovery is modelled, simulated and optimised. The carbon recovery segment consists of a post-combustion chemical absorption carbon capture from the exhaust flue of the BIGCC using potassium carbonate as solvent. The presented integrated system is able to produce electricity from date pits at a negative carbon credit. Thus, this system aims at recycling waste for the generation of valuable commodities, reducing GHG emissions and diversifying the energy portfolio, all feeding into the concept of sustainability. The proposed system is simulated as a thermodynamic equilibrium model for the BIGCC and and a rate-based model for the carbon capture segment in Aspen Plus software. The energy and exergy efficiencies for the overall system are calculated and optimised. Several parametric studies were conducted to select impactful operating parameters and their ranges for the optimisation model. Outcomes of this study indicate that the proposed system generates 420 kW of electricity and captures 80% of the CO 2 emitted from the BIGCC. The integrated system achieves maximum energy and exergy efficiencies of 54% and 61% respectively.