Temperature control of an energy integrated solid oxide fuel cell system

An energy integrated solid oxide fuel cell (SOFC) system was presented by using a benefit of the high temperature of SOFC exhaust gas to transfer for all heat exchangers in SOFC system. Its high operating temperature provides the potential for energy integration and higher overall system efficiencies. The SOFC system represents the multi-loop control system in which the main control objectives are temperatures of the SOFC and the target streams of heat exchangers. In designing temperature control system, the air flow rate fed into SOFC and the valve position of SOFC hot stream splitter are identified as the manipulated variables to keep the main control variables of SOFC temperature and steam reformer temperature, respectively. In this study, the temperature control system for energy integrated SOFC system was designed by using a two-degree of freedom controller. The designed PI controller presents a good efficiency to maintain the control variables and reject the disturbance.