Production of hydrogen employing Ni-Rh catalysts in membrane reactors

J. MÚNERA , S. IRUSTA, L. M. CORNAGLIA, E. A. LOMBARDO

LATIN AMERICAN APPLIED RESEARCH

Management

Lugar: Bahia Blanca; Año: 2003 vol. 33 p. 73 - 78

0327-0793

Rh, Ni, and Rh-Ni catalyst were prepared by wet impregneation of La2O3. The Rh content was modified but the Ni loading was kept constant at 2 wt%. The solids were calcined at 823 K in air flow and were reduced at 97 3K in flowing hydrogen. The activity, stability, and residue formation during the CO2 reforming of CH4, of all the catalysts were tested in a fixed-bed reactor. Those with low carbon deposition were used in a Pd-Ag membrane reactor. The Rh solids showed the highest activity at 823 K. In order to understand the Rh effect, the catalysts were characterized through XRD and TPR. No evidence of crystalline Ni phase through XRD was observed in either the calcined or used catalysts. On the other hand, both the TPR and XPS results suggest a significant metal-support interaction. The bimetallic solids presented higher carbon deposition. The carbonaceous species formed on stream were characterized through thermal analysis. At least two types of carbons were detected on the catalyst surface with different structural properties which did not affect the catalytic activity. A low carbon deposition was observed on Rh/La2O3 which exhibited a stable activity after 100 h on stream. The monometallic Rh solids were tested in the membrane reactor, varying the pressure drop across the Pd-Ag alloy. A significant increase in reactant conversions was obtained when the membrane reactor was used.