Dr. Marilena Avrigeanu
Associate Professor, School of Chemical Engineering and Technology, Xi'an Jiaotong University, China

Speech Title: Steady-state modelling and performance optimization of biogas fueled SOFC-IC Engine hybrid power generation system

Abstract: Sustainable development of human society has reached consensus all over the world. In the energy field, an efficient and clean energy conversion way is viewed to be effective and crucial for achieving the sustainable development. With the rapid development of emerging countries, the energy consumption increases dramatically and the environmental issues such as global warming and emissions of pollutants become serious. In this context, innovative technologies for energy conversion are in urgent need for the conventional conversion of fossil fuels to meet the demands of ultra-high conversion efficiency and ultra-low environmental impact in the meanwhile. Among these innovation technologies, FCs usually have ultra-high conversion efficiencies and near-zero emissions due to that the fuel is oxidized by electrochemistry to generation electricity and heat without combustion. It is exactly because of the unique characteristic that fuel cell (FC) power technology is attracting as high-efficiency energy conversion system. Moreover, the electrochemical reaction occurring in FCs is highly exothermic with the reaction heat of 242 kJ/mol, indicating that a large amount of heat is released and can be utilized to drive bottomed thermodynamic cycles such as Rankine and Brayton cycles. In this case, the combination of FCs and engines into hybrid power systems not only can adequately utilize waste heat to improve the energy conversion efficiency, but also extends the power range to facilitate practical applications. Specially, coupling solid oxide fuel cell (SOFC) can achieve the theoretical conversion efficiency up to more than 70%, nearly twice times larger than the standalone IC engine, due to extremely high operating temperature for SOFC. In addition, the high operating temperature makes the hybrid power system’s fuel flexible, such as CH4, biogas, NG and petroleum gas, which are cheaper and easier to manage than pure H2. This is because that the reforming and water gas shift (WGS) reactions generally take place inside SOFC to convert the components of hydrocarbon and CO into hydrogen in the present of water and high temperature. In the present study, the steady-state model of biogas fueled SOFC-IC engine hybrid power system is established, and the parametric and exergy analyses are carried out for performance optimization. The results contribute to develop optimization rule and operation strategy for the biogas fueled SOFC-IC engine hybrid power generation system, which is significant and valuable for motivating the practical applications of hybrid power technology.

Keywords: Biogas, SOFC, Internal combustion engine, Energy conversion efficiency, Exergy analysis

Acknowledgements: This work was financially supported by the National Natural Science Foundation of China (No. 21736008) and the China Postdoctoral Science Foundation (No. 2016T90913).