Multi-dimensional modeling of sulfuric acid decomposer for thermochemical hydrogen production

The sulfuric acid decomposition process is a critical step in sulfur-based thermochemical hydrogen production, operating under very high-temperature conditions. A three-dimensional fixed-bed reactor for sulfuric acid decomposition was modeled using the finite volume method, incorporating mass transfer and reaction kinetics. To optimize reactor operation, the efficacy coefficient method was employed. An acid-resistant experimental platform was constructed to validate the model. Simulations predicted that a reactor with 1 wt% Pt catalyst could achieve a sulfuric acid-to-sulfur dioxide conversion ratio of 79.46 % to 88.25 % when the reactor temperature ranged from 1073 K to 1233 K at 1 bar. Experimental results under the same conditions demonstrated conversion ratios from 79.43 % to 84.03 %, with deviations between 0.04 % and 4.78 % from the simulation. The optimal gas-hourly space velocities (GHSVs) at varying boundary temperatures were determined to be 6072.82 h^-1, 6202.52 h^-1, 6549.94 h^-1, and 6750.04 h^-1, respectively. Overall, the computational model and experimental results exhibited strong agreement.