Computational design of H 2 SO 4 decomposer combined with SOFC for thermochemical hydrogen production

Summary Thermochemical methods, such as the sulfur‐iodine cycle and hybrid sulfur cycle, are more advantageous than conventional hydrogen production methods, such as fossil fuel reforming and water electrolysis, for large‐scale hydrogen production. Sulfuric acid decomposition is a highly endothermic reaction of the sulfur‐iodine cycle. To sustain this endothermic process using high‐temperature waste heat from solid oxide fuel cells (SOFCs), we propose an integrated thermochemical reactor combined with SOFC by taking a computational approach. First, a thermodynamic analysis was performed to evaluate the heat production of SOFC to sustain the thermochemical reaction in the combined reactor, resulting in a required waste heat of 0.565 kW from the SOFC that was obtained by consuming 0.0241 kg‧h −1 of H 2 to process 1.0 kg‧h −1 of the H 2 SO 4 mixture for the H 2 SO 4 decomposer. For the SOFC inlet temperatures 923, 1023, and 1173 K, the corresponding SO 3 conversions of the combined reactor were 72.1%, 77.3%, and 85.1%, respectively. A further increase of over 1200 K in the operating temperature led to a minor improvement in the SO 3 conversion efficiency. In the SOFC section, the H 2 mass fraction decreased from 67.9% to 10.8% in the anode channel, and 0.169 kW of electrical power was generated when the operating cell voltage and energy efficiency were 0.7 V and 53.71%, respectively.