Adsorption model for biogas purification: A design tool for solid oxide fuel cells applications

Abstract

With biogas production projected to exceed 35–45 billion cubic meters by 2030, addressing the critical challenge of biogas purification to allow its exploitation through the best-in-class technology available, the solid oxide fuel cell (SOFC), while preserving their durability, is essential. This study investigates the decontamination aspects related to the energy option of SOFCs fueled by biogas, a highly efficient and sustainable solution for renewable energy generation. We have developed a flexible and cost-effective biogas cleaning unit capable of removing harmful sulfur-based impurities. A novel adsorption model was created to predict contaminant concentration profiles, supporting the design of scalable cleaning units. Our comprehensive techno-economic analysis reveals that in 3-kW systems, capital and operational expenditures for SOFCs account for 56–70 % of the levelized cost of electricity (LCOE), with biogas cleaning systems constituting 30–37 % in single-vessel configurations and 35–44 % in lead-and-lag setups. In 100-kW systems, economies of scale reduce SOFC investment costs, while the impact of the biogas cleaning system becomes more pronounced. Sensitivity analysis indicates that variations in sorbent costs significantly affect LCOE, with lead-and-lag configurations offering advantages in sorbent utilization and operational efficiency. Overall, our findings indicate that biogas-SOFC systems obtain a competitive LCOE, below 0.32 €/kWh for 3-kW systems and below 0.12 €/kWh for 100-kW systems. This highlights their viability as a cleaner, high-efficiency alternative to conventional combustion technologies for decentralized energy production.