A study on catalytic hydrogen production: Thermodynamic and experimental analysis of serial OSR-PROX system

Steady state performance of OSR and serial OSR-PROX reactors were investigated. OSR of methane/propane and PROX were conducted over novel Pt-Ni/delta-Al2O3 and Pt-Sn/AC catalysts, respectively. OSR (623-773 K) and PROX (383-388 K) reactors' temperature combination, S/C ratio (2.25-6) in the OSR feed, and W/F-O2 ratio (1.5-12.2 mg-cat.min/mu mol) in the PROX feed, which was adjusted through oxygen addition to OSR outlet at rates on the basis of CO molar flow in the OSR outlet, were used as the experimental parameters. Simultaneous use of high temperature and high S/C ratio led to increased H-2 and H-2/CO ratios, and decreased CH4 and CO2 concentrations in OSR product. In serial tests, the highest achieved H-2 concentration was 66% (dry based inert free) at S/C ratio of 6 at 723 K, while the lowest CO concentration was 700 ppm at OSR-PROX temperature combination of 723 & 383 K. Maximum achieved methane and propane conversions at 723 K were 70% and 100%, respectively. Oxygen fed to OSR was totally consumed in all tests. OSR temperature of 723 K, S/C ratio of 5, PROX temperature of 383 K and W/F-O2 ratio of 1.53 in the PROX feed were the optimal parameters targeting high H-2/CO product ratio. The experimental product distribution trends were consistent with the results of the thermodynamic equilibrium calculations.