Thermodynamic modeling of sulfuric acid decomposer integrated with 1 MW tubular SOFC stack for sulfur-based thermochemical hydrogen production

[Display omitted] •Integration of sulfuric acid decomposer with tubular SOFC stack is thermodynamically studied.•Equilibrium conversion, energy assessment, and influence of operating conditions is investigated.•SO3 decomposition performance is assessed with different catalysts.•Energy requirement for H2SO4 decomposition, SO2 production capacity, and thermal efficiency of integrated system are analyzed using pinch analysis. This study developed a thermodynamic model of a set of sulfuric acid decomposers for thermochemical hydrogen production. It was integrated with a 1 MW tubular-type solid oxide fuel cell (SOFC) stack. With the model, we evaluated the feasibility of the combined production of electric power, heat, and sulfur dioxide for thermochemical H2 production. The integrated reactor model consists of three parts: i) SOFC submodel, ii) sulfuric acid decomposition (SAD) submodel, and iii) sulfur trioxide decomposition (STD) submodel with the catalysts Pt/γAl2O3 and WX-1. The efficiency of the integrated system was evaluated at a low-pressure range by polarization and efficiency curves for the SOFC, as well as pinch analysis for the SAD. The highest SOFC efficiency and SO2 production were achieved at 1.25 bar, whereas the lowest fuel consumption and heat demand for SO2 production were achieved at 3.0 bar. Furthermore, WX-1 performed better in the high-temperature range, whereas Pt/γAl2O3 performed better than WX-1 under low-temperature conditions. The Pt-supported catalyst could achieve SO3 conversion of 66% and SO2 yield of 57% at a gas temperature of 1025 K using the proposed integrated reactor design.