Thermally self-sustaining operation of tubular solid oxide fuel cells integrated with a hybrid partial oxidation reformer using propane

Tubular solid oxide fuel cells (SOFCs) can be applied in a diverse range of applications, such as critical military missions, auxiliary power units, and portable power generators. In particular, portable power-generation devices may have to meet the requirements of rapid start-up, thermally self-sustaining operation, high thermal shock resistance, and high power density relative to the weight. This work presents the design and performance of a tubular SOFC stack integrated with a hybrid catalytic partial oxidation (CPOX) reformer, an afterburner (A/B), and a heat exchanger (HEX), which enables the stack operation without any external heat source with propane as a fuel. The SOFC stack that was made with four anode-supported tubular SOFCs was assembled with fuel and air chambers. The hybrid COPX reformer that was fed with a pre-mixture of propane and air acted as a start-up burner at the initial period operation to heat the stack up and then a reformer to provide a syngas to the stack when it reached an elevated temperature (700–800 °C). The A/B also provided heat energy to the stack by oxidizing the unreacted fuel and air of the stack anode and cathode exhaust, respectively. The stack first underwent a pre-treatment which reduced the anode support in a programmable furnace. The preliminary electrochemical performance of the stack was assessed while feeding a mixture gas of H₂ and N₂ as the fuel. Next, the pre-treated stack was integrated with the hybrid reformer, A/B, and HEX and insulated to investigate the thermally self-sustaining rapid operation capabilities by using propane as the fuel. In the integrated SOFC system, the stack reached 780 °C within an hour upon operation and generated 12 W of output power, thus demonstrating the feasibility of the system for portable power generations.