Thermo-economic optimization of a solid oxide fuel cell, gas turbine hybrid system

Large scale power production benefits from the high efficiency of gas-steam combined cycles. fit the lower power range, fuel cells are a good candidate to combine with gas turbines. Such systems can achieve efficiencies exceeding 60%. High-temperature solid oxide fuel cells SOFC) offer good opportunities for this coupling. In this paper a systematic method to select a design according to user specifications is presented. The most attractive configurations of this technology coupling art? identified using a thermoeconomic multi-objective optimization approach. The SOFC model includes detailed computation of losses of the electrodes and thermal management. The system is integrated using pinch based methods. A thermo-econonnic approach is then used to compute the integrated system performances, size, and cost. This allows to perform the optimization of the system with regard to two objectives: minimize the specific cost and maximize the efficiency Optimization results prove the existence of designs with costs from 2400 $ / kW for a 44% efficiency to 6700 $ /kW for a 70% efficiency. Several design options are analyzed regarding, among others fuel processing, pressure ratio, or turbine inlet temperature. The model of a pressurized SOFC-mu GT hybrid cycle combines a state-of-the-art planar SOFC with a high-speed micro-gas turbine sustained by air bearings.