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Steam reforming of n-heptane using a Rh/MgAl

1989; Elsevier BV; Volume: 47; Issue: 1 Linguagem: Inglês

10.1016/s0166-9834(00)83264-9

1873-3867

Hideaki Muraki, Yoshiyasu Fujitani,

Catalytic Processes in Materials Science

A Rh/MgAl2O4 catalyst was found to be active for the steam reforming of n-heptane in the range 400–500°C. The MgAl2O4 support was prepared by calcining of a mixture of α-alumina and magnesia powders at 1420°C. The development of pore structure in MgAl2O4 support was examined with SEM, XRD and porosimetry before and during calcination. The pores are found to originate from voids among MgAl2O4 particles produced by solid reaction that magnesia was diffusing to alumina particles. Therefore, the pore size is able to control as a result of control of alumina particle size. In order to clarify the role of this support, a kinetic study on the reaction between n-heptane and steam was conducted at 500°C and 1 atm. The initial reaction rate, r0 (mol g−1h−1), obtained experimentally is best expressed by the following equation: r0=k(KP0C7H161+KP0C7H16)(K′P0H2O1+K′P0H2O) wherek (0.071 mol/g h) is the apparent rate constant, p0j are the partial pressures of reactantsj in the feed gas andK (111 atm−1) andK′ (0.712 atm−1) are the adsorption equilibrium constants for n-heptane and water, respectively. It is confirmed that steam reforming of n-heptane proceeds through the adsorption of n-heptane on rhodium metal and of steam on the support surface. The characteristics of the composition distribution of products shows that carbon monoxide is a primary product in the reaction system and both carbon dioxide and methane are the secondary products.