A kinetic model-based SOFC combined cycle power generation system for waste heat recovery

Abstract

Solid oxide fuel cell (SOFC) is an extremely promising technology for sustainable energy conversion and storage through highly efficient electrochemical reaction at high-temperature conditions. The existing studies commonly address the final equilibrium state of the SOFC electrode reactions, giving less consideration to the micro kinetic of electrode reactions. In this paper, a kinetic model-based SOFC combined cycle power generation system is suggested to recover multiple waste heat, which includes a Kalina cycle (KC) as the bottom cycle and a Rankine cycle (RC) as the top cycle. In devneloping the proposed system, a novel kinetic model is presented for SOFC based on the microscopic mechanism of the oxygen reduction. A dynamic stochastic programming model is established to optimize the integrated system sequentially and simultaneously, with maximum power generation taken as the objective, depending on whether the SOFC system and the KC-RC system are simultaneously optimized. In sequential optimization, the output power of SOFC-KC-RC system is 320.56 kW and it is 415.04 kW using simultaneous optimization, achieving a 29.5% increase in power generation. Further comparison with the previous reports obtained by a thermodynamic model, this work leads to a 10.8% increase in power generation, showing the promising power production performance of the developed system.