• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.353-356
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• 2009

A pivotal mechanical balance of plant for 75kW class molten carbonate fuel cells comprise of a catalytic burner and an ejector which has been designed and tested in KEPRI(Korea Electric Power Research Institute). The catalytic burner, which oxidizes residual fuel in the anode tail gas, was operated at several conditions. Some problems arose due to local overheating or auto-ignition, which could limit the catalyst life. The catalytic burner was designed by considering both gas mixing and gas velocity. Test results showed that the temperature distribution is very uniform. In addition, an ejector is a fluid machinery to be utilized for mixing fluids, maintaining vacuum, and transporting them. The ejector is placed at mixing point between the anode off gas and the cathode off gas or the fresh air Several ejectors were designed and tested to form a suction on the fuel tail gas and balance the differential pressures between anode and cathode over a range of operating conditions. The tests showed that the design of the nozzle and throat played an important role in balancing the anode tail and cathode inlet gas pressures. The 75kW MCFC system built in our ejector and catalytic burner was successfully operated from Novembe, 2008 to April, 2009. It recorded the voltage of 104V at the current of 754A and reached the maximum generating power of 78.5kW DC. The results for both stand-alone and integration into another balance of plant are discussed.

• Journal of Hydrogen and New Energy
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• v.30 no.4
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• pp.303-311
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• 2019

Reversible solid oxide fuel cell (RSOFC) has become a prospective device for energy storage and hydrogen production. Many studies have been conducted around the world focusing on system efficiency improvement and realization. The system should have not only high efficiency but also a certain level of simplicity for stable operation. External waste steam utilization was proved to remarkably increase the efficiency at solid oxide electrolysis system. In this study, RSOFC system coupled with waste steam was proposed and optimized in term of simplicity and efficiency. Ejector for fuel recirculation is selected due to its simple design and high stability. Three system configurations using ejector for fuel recirculation were investigated for performance of design condition. In parametric study, the system efficiencies at different current density were analyzed. The system configurations were simulated using validated lumped model in EBSILON(R) program. The system components, balance of plants, were designed to work in both electrolysis and fuel cell modes, and their off-design characteristics were taken into account. The base case calculation shows that, the system with suction pump results in slightly lower efficiency but stack can be operated more stable with same inlet pressure of fuel and air electrode.