Hybrid CSP biomass CO2-gasification process for power production: ASpen plus simulation

Abstract

Generally, biomass gasification takes place in the presence of a gasifying agent like steam, air, oxygen, carbon dioxide (CO2) or any combination of these gasifying agents. There have been recent interests of utilizing CO2 as a gasification agent, with the advantage of less tar production and better char quality. In this study, CO2 is used as a gasifying agent in the hybrid CSP-biomass integrated gasification combined cycle (IGCC) process for power generation and the simulation results were compared with CSP – biomass steam IGCC system. The aim is to assess the potential use of CO2 as a gasifying agent and to learn more about its effects on the gasification process. In this study, ASPEN Plus was used to develop a simple model for CSP-assisted biomass gasification to produce synthetic gas (syngas). This was followed by an integrated gasification combined cycle (IGCC) system for power production. The effect of operating temperature of the gasification system was studied to determine the optimum temperature. It was found that gasification temperature of about 800oC is good enough to achieve maximum energy efficiency. The peak net efficiency of hybrid CO2-gasification IGCC system is 46% which is slightly higher than steam IGCC process which is 45%; it is higher than other hybrid options found in the literature. A solar thermal to power efficiency of 55% is achieved in hybrid CO2 gasification which is less than hybrid steam gasification which is 58%. Hybrid CSP CO2-biomass IGCC is a promising process for dispatchable power supply.