Investigation of a Novel Near-Zero Emission Poly-Generation System Based on Biomass Gasification and SOFC: A Thermodynamic and Exergoeconomic Evaluation

SOFC poly-generation system exhibits the potential for clean and efficient conversion, but few studies have been conducted on the comparative analysis of the combined cooling, heating and power considering CO2 capture and condensate recovery. This study investigates a novel near-zero emission poly-generation system based on biomass gasification and SOFC employing different biomass fuels. This combined system adopting oxy-fuel combustion instead of traditional pre-combustion makes the flue gas easier to achieve a concentrated CO2 stream, thereby the system structure is simplified and the purity of captured CO2 is improved. The results reveal that the larch wood is the preferred fuel for the proposed system and the corresponding overall efficiency, exergy efficiency and unit cost of products achieve 80.17%, 29.12% and 20.49 $/GJ, respectively. The exergy analysis demonstrates that the exergy destruction mainly occurs in gasifier and turbine. The exergoeconomic analysis indicates that SOFC possesses a greater exergoeconomic factor of 85.12%. The parametric analysis shows that increasing gasifier temperature (Tgas), SOFC temperature difference (ΔT) and current density (j) decreases overall efficiency. The higher Tgas results in a higher unit cost (ct), whereas ct is more economic as ΔT increases. Besides, as j changing, ct of various biomass-based systems exists an optimal value.