A Kinetic Study of Ethanol Steam Reforming Using a Nickel Based Catalyst

Abstract

A kinetic study of ethanol steam reforming to produce hydrogen within the region of kinetic rate control was carried out. A Ni(II)-Al(III) lamellar double hydroxide as catalyst precursor was used. H 2 , CO, CO 2 and CH 4 were obtained as products. Using the Langmuir-Hinshelwood (L-H) approach, two kinetic models were proposed. The first was a general model including four reactions, two of them corresponding to ethanol steam reforming and the other two to methane steam reforming. When high temperatures and/or high water/ethanol feed ratios were used, the system could be reduced to two irreversible ethanol steam reforming reactions.

Process simulation and optimization of H2 production from ethanol steam reforming and its use in fuel cells. 2. Process analysis and optimization

“…This model has been applied by us to a full set of experimental data collected for a Ni/Al2O3 sample [31]. This allowed to represent with good accuracy the experimental data, validating the proposed model also for a different catalytic system, and to provide a reliable estimate of the whole set of kinetic parameters needed for the present simulations and for steam reformer reactor sizing, as summarised in Table 1.…”

“…WGS and SRM in this case are not occurring alone on catalyst surface, but they are part of a complex reaction mechanism. Based on aLangmuir Hinshelwood approach, all the species concurring for adsorption over active sites should appear in the denominator of the rate expressions and are included in the overall balance on the active sites, leading to complex rate equations.This model has been applied by us to a full set of experimental data collected for a Ni/Al2O3 sample [31]. This allowed to represent with good accuracy the experimental data, validating the proposed model also for a different catalytic system, and to provide a reliable estimate of the whole set of kinetic parameters needed for the present simulations and for steam reformer reactor sizing, as summarised in Table 1.…”

Process Simulation for the Design and Scale Up of Heterogeneous Catalytic Process: Kinetic Modelling Issues

“…Data taken from reference [51] (see also references therein) for the rates of the above rate determining steps (RDS) and for the adsorption equilibria of the relevant species on the catalyst: the constants are calculated at 818 K and the tolerances at the 95% confidence level. In parallel, Mas and coworkers [52] developed the reforming mechanism considering the production of methane, giving less importance to the aldehyde as a kinetically relevant intermediate, but helping to establish the methanation reaction as a RDS itself (rather than a fast equilibrium stage), accounting for the different behavior of this species on different catalysts.…”

Kinetic Modelling at the Basis of Process Simulation for Heterogeneous Catalytic Process Design

“…At a glance, the main findings of this work are reported in Table 12. In parallel, Mas and coworkers [44] developed the reforming mechanism considering the production of methane, giving less importance to the aldehyde as a kinetically relevant intermediate, but helping to establish the methanation reaction as a RDS itself (rather than a fast equilibrium stage), accounting for the different behavior of this species on different catalysts.…”