Research on Distributed Energy Supply System Based on Molten Carbonate Fuel Cell

The fuel cell-based distributed energy supply system has low pollution emission, low noise, and modular advantages. This paper aims at a 100 kW-class MCFC cogeneration system using natural gas as fuel. The MCFC unit model was developed based on the lumped parameter method. A parallel system and a series system model were built. The effect of single cell voltage and fuel cell stack arrangement on system efficiency, operating temperature, catalytic burner operating parameters, etc. are analyzed. As a result, the series system in which two fuel cell stacks arranged in series can improve the stack efficiency and the system power generation efficiency. Compared to a parallel system in which two fuel cell stacks arranged in parallel, the stack efficiency and the system power generation efficiency of the series system are 6 to 8 percentage points higher than that of the parallel system. For the series system, the air needed to be graded to maintain the operating temperature of the second-stage stack, the air ratio was about 2.75; the power ratio of the two stacks was about 8.0. Compared with the catalytic burner in the parallel system, the inlet burner temperature in the series system increased by about 50 °C, and the inlet hydrogen mole fraction in the series system was reduced by 1 percentage point. The heat balance design of the catalytic burner in the series system was required.