Pooya Estifaee

CO oxidation over sonochemically synthesized Pd–Cu/Al2O3 nanocatalyst used in hydrogen purification: Effect of Pd loading and ultrasound irradiation time

The bimetallic Pd-Cu nanocatalysts with different Pd loadings and ultrasonic irradiation times were sonochemically synthesized and their activities toward CO oxidation were investigated. XRD, FESEM, TEM, BET, FTIR and TG-DTG techniques were employed in nanocatalysts characterization. XRD data confirmed formation of CuAl2O4 spinel with an average crystallite size of 4.9 nm. FESEM images revealed more uniform pattern and also fewer agglomerations were observed by increasing ultrasonic irradiation time. In agreement with FESEM result, TEM images depicted nanoparticles and uniform dispersion of active phase over alumina. BET surface analysis showed that increasing the Pd loading has no significant effect on surface area; whereas by increasing irradiation time the surface area increases slightly. Catalytic performance tests of synthesized samples showed that Pd(1.5%)-Cu(20%)/Al2O3 with 95 min ultrasonic irradiation time had the best activity over the course of reaction. In addition, increasing CO at feed composition revealed that among synthesized nanocatalysts with 0.5%, 1% and 1.5% of Pd, synthesized sample with 1.5% of Pd had the best low-temperature activity.

Simulation study of an auto-thermal double-membrane reactor for the simultaneous production of hydrogen and methanol: comparison of two different hydrogen redistribution strategies along the reactor

Abstract In a continuing effort to realize the simultaneous hydrogen and methanol production via the auto-thermal methanol synthesis process, the effect of two different hydrogen redistribution strategies along a double-membrane reactor has been considered. A steady-state one-dimensional heterogeneous model was developed to compare two strategies applied in the operation of the auto-thermal methanol synthesis. It was found that the counter-current configuration exhibited the better performance compared to the reactor operated in the co-current mode from both the economic and environmental points of view. This superiority is ascribed to the establishment of a more favourable temperature profile along the reactor and also more hydrogen extraction from the reaction zone. Moreover, the influence of some operating variables was investigated on the performance of the auto-thermal double-membrane reactor in the counter-current configuration. The results suggest that utilizing this configuration for pure hydrogen and methanol production could be feasible and beneficial.