A dynamical model for a 5kW class solid oxide fuel cell (SOFC) combined heat and power (CHP) test station has been composed using the APROS® environment. The model is based on a real test station being constructed and operated at VTT Technical Research Centre of Finland and it comprises the following main components of the real test system: the autothermal reforming unit, SOFC stack situated inside a furnace, catalytic afterburner, and three heat exchangers. The constructed model has been verified against experimental results obtained from the autothermal reforming unit, catalytic afterburner, and the two cathode side heat exchangers. The model has been used for the phenomenological studies of the system during current transient simulations using a simplified and fast zero-dimensional model including internal reforming reactions for the SOFC stack. The test station model was capable of operating at a speed of 18 times the real time using a standard personal computer.

The behavior of the maximum temperature measured inside a SOFC stack with respect to three independent input variables (stack current, air flow and air inlet temperature) is examined by using a full factorial screening experiment, following the design of experiments methodology. The experiments were carried out with a complete 10 kW e SOFC system. Multivariate regression models are developed to estimate said temperature and a statistical analysis is carried out on the model parameters.

The effect of anode off‐gas recycling (AOGR) on the characteristic performance of a natural gas reformer equipped with a precious metal catalyst is investigated experimentally. The reformer is operated both with synthetic AOGR gas and in steam reforming (SR) conditions. The characteristic performance in SR and AOGR mode are compared with equilibrium, and it is found that equilibrium is more readily achieved in AOGR mode. The reformer is used for extended periods of time (100–1,000 h) in conditions where carbon formation is thermodynamically possible to measure any changes in characteristic performance. No significant change in the performance is observed due to carbon formation or catalyst deactivation. The reformer could be successfully implemented in a 10 kW SOFC system with an anode off‐gas recycling loop.

Three different planar anode supported solid oxide fuel cells (SOFC) were tested with hydrogen, with autothermally prereformed natural gas from which sulfur was removed, and with autothermally prereformed natural gas that contained sulfur. The cells were obtained from Forschungszentrum Jülich (FZJ), Energy research Centre of the Netherlands (ECN), and HTceramix SA (HTc). All cells were so called Real-SOFC first generation cells. Cell polarizations were first measured with hydrogen, followed by a 200h test (25A, 800°C) with a selected fuel, and finally cell polarizations were measured with hydrogen. When hydrogen was used as the fuel in the 200h test, the performance for all cells was comparable and no degradation was observed. All cells underwent an initial deactivation process when reformate fuels were used but their cell voltage stabilized during the first 50h. All cells also showed deactivation after the reformate tests when the area specific resistance values were compared to the values obtained from the hydrogen tests. The deactivation was comparable between the sulfur-free and sulfur-rich reformate tests. Sulfur-rich reformate, however, caused oscillation in cell voltages as the sulfur level in natural gas was not constant.

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