Production of hydrogen over bimetallic Pt-Ni/δ-Al2O3. I. Indirect partial oxidation of propane

Abstract Indirect partial oxidation (IPOX) of propane was studied over bimetallic 0.2 wt.% Pt–15 wt.% Ni/δ-Al 2 O 3 catalyst in the 623–743 K temperature range. The unreduced and reduced forms of the catalyst were characterized by ESEM–EDAX and X-ray diffraction (XRD). In the IPOX tests, the effects of steam to carbon ratio (S/C), carbon to oxygen ratio (C/O 2 ) and residence time ( W / F (g cat  h/mol HC)) on the hydrogen production activity, selectivity and product distribution were studied in detail. The effect of temperature program applied (increasing from 623 to 743 K, ITP; decreasing from 743 to 623 K, DTP) during reaction was also tested. The results showed that the Pt–Ni bimetallic system has superior performance characteristics compared to the monometallic catalysts reported in literature. The reason is thought to be the utilization of the catalyst particles as micro heat exchangers during IPOX; the heat generated by Pt sites during exothermic total oxidation (TOX) being readily transferred through the catalyst particles acting as micro heat exchangers to the Ni sites, which promote endothermic steam reforming (SR). The optimal conditions were found as S/C = 3, C/O 2  = 2.70 and W / F  = 0.51 g cat  h/mol HC for IPOX of propane on the basis of high hydrogen productivity and selectivity between 623 and 748 K for the experimental conditions tested. The thermo-neutral points obtained showed the sustainability of reaction in terms of energy.

[1]  K. Kunimori,et al.  Catalyst development for direct heat supply from combustion to reforming in methane reforming with CO2 and O2 , 2003 .

[2]  David L. Trimm,et al.  ONBOARD FUEL CONVERSION FOR HYDROGEN-FUEL-CELL-DRIVEN VEHICLES , 2001 .

[3]  David L. Trimm,et al.  Vehicle exhaust catalysis: I. The relative importance of catalytic oxidation, steam reforming and water-gas shift reactions , 1995 .

[4]  Detlef Stolten,et al.  Small-scale testing of a precious metal catalyst in the autothermal reforming of various hydrocarbon feeds , 2002 .

[5]  David L. Trimm,et al.  The design and testing of an autothermal reactor for the conversion of light hydrocarbons to hydrogen I. The kinetics of the catalytic oxidation of light hydrocarbons , 1996 .

[6]  D. Trimm,et al.  Alternative catalyst bed configurations for the autothermic conversion of methane to hydrogen , 1996 .

[7]  David L. Trimm,et al.  Heterogeneous reactor modeling for simulation of catalytic oxidation and steam reforming of methane , 2001 .

[8]  A. Ghenciu,et al.  Review of fuel processing catalysts for hydrogen production in PEM fuel cell systems , 2002 .

[9]  V. Choudhary,et al.  Partial oxidation of methane to syngas with or without simultaneous CO2 and steam reforming reactions over Ni/AlPO4 , 1998 .

[10]  Z. Önsan,et al.  Ignition Characteristics of Pt, Ni and Pt-Ni Catalysts Used for Autothermal Fuel Processing , 2003 .

[11]  Ryuji Kikuchi,et al.  Catalytic autothermal reforming of methane and propane over supported metal catalysts , 2003 .

[12]  Z. Önsan,et al.  Hydrogen production by steam reforming of n-butane over supported Ni and Pt-Ni catalysts , 2004 .

[13]  M. Krumpelt,et al.  Hydrogen from hydrocarbon fuels for fuel cells , 2001 .

[14]  Runyu Ma,et al.  Characterization of alumina-supported Ni and Ni-Pd catalysts for partial oxidation and steam reforming of hydrocarbons , 2003 .