An auto-sustainable solid oxide fuel cell system fueled by bio-ethanol: Process simulation and heat exchanger network synthesis

In this paper the simulation and heat integration of a solid oxide fuel cell (SOFC) integrated with an ethanol steam reforming system are carried out. The ethanol reaction is studied using a novel kinetic model reported in a previous work. The system and fuel cell efficiencies are studied under different process conditions, temperature (723 < T < 873 K), water to ethanol molar ratio (3 < RAE < 6) and fuel utilization coefficient (0.7 < FUC < 0.9). The SOFC off gases are mixed and fed to an after burner providing heat to the process. Two heat exchanger networks are designed considering the influence of the fuel utilization coefficient (0.7–0.9) at the cell electrodes. If the SOFC is operated at FUC < 0.8 a self sufficient limit could be established, otherwise extra ethanol must be combusted with an overall efficiency penalty. A process flow diagram is proposed in order to obtain a high efficiency and to avoid the use of any external source of energy.