Optimization of solid oxide fuel cell system integrated with biomass gasification, solar-assisted carbon capture and methane production

Abstract

Direct power generation from biomass gasification using solid oxide fuel cell (BioG-SOFC) have shown significant advantages over its conventional power generation counterpart. However, unburnt syngas at the SOFC exhaust presents a major issue for this system. This study investigates new method using water gas shift membrane reactor-burner for syngas conversion along with direct low-cost CO2 separation for economic carbon caption. Full factorial statistical optimization is performed to maximize the technoeconomic performance for wide range of multi-hybrid system configurations including cooling/heating heat recovery (CCHP), organic Rankine cycle (ORC) and co-electrolysis using PV surplus power for methane production. BioG–SOFC–CCHP achieved energy efficiencies of 69.6% and 76% and exergy efficiencies of 42.2% and 43.3% for cooling and heating models, respectively. The system can meet a 10 year payback time over 20-year lifespan when the electricity and methane selling prices are 0.13$/kWh and 18$/GJ. After two-stage full-factorial optimization for Different configurations from the sub-system level and overall system level under designed parameter conditions. The energy, exergy, and economic performance have been improved. The optimization elevated the exergy efficiency up to 53.6% for the BioG –SOFC– CCHP hybrid system, and the whole system payback time decreased to 9.3 years with higher NPV/kW of 14.25 k$/kW.