A Study on CO2 Methanation and Steam Methane Reforming over Commercial Ni/Calcium Aluminate Catalysts

Abstract

Three Ni-based natural gas steam reforming catalysts, i.e., commercial JM25-4Q and JM57-4Q, and a laboratory-made catalyst (26% Ni on a 5% SiO2–95% Al2O3), are tested in a laboratory reactor, under carbon dioxide methanation and methane steam reforming operating conditions. The laboratory catalyst is more active in both CO2 methanation (equilibrium is reached at 623 K with 100% selectivity) and methane steam reforming (92% hydrogen yield at 890 K) than the two commercial catalysts, likely due to its higher nickel loading. In any case, commercial steam reforming catalysts also show interesting activity in CO2 methanation, reduced by K-doping. The interpretation of the experimental results is supported by a one-dimensional (1D) pseudo-homogeneous packed-bed reactor model, embedding the Xu and Froment local kinetics, with appropriate kinetic parameters for each catalyst. In particular, the H2O adsorption coefficient adopted for the commercial catalysts is about two orders of magnitude higher than for the laboratory-made catalyst, and this is in line with the expectations, considering that the commercial catalysts have Ca and K added, which may promote water adsorption.

Heterogeneous Catalysis in (Bio)Ethanol Conversion to Chemicals and Fuels: Thermodynamics, Catalysis, Reaction Paths, Mechanisms and Product Selectivities

“…Thus, while it seems likely that on cobalt catalysts ethanol steam reforming implies first a dehydrogenation to acetaldehyde, and later the steam reforming of acetaldehyde, on nickel it is still not known what is the origin of residual methane and what is the real molecule being steam reformed. To unravel this point, we investigated three reactions over a commercial catalyst: methane steam reforming (MSR), CO 2 methanation [13,69] and ethanol steam reforming (ESR).…”

“…Working with different Most of the catalytic experiments were performed in quasi steady state (SS) conditions, as described in detail in Ref. [13]. Temperature-Programmed Surface Reaction (TPSR) experiments were also realized in the same line with continuous temperature increase and continuous online product analysis.…”

“…13, 3587 8 of 20 up to above 90 % at 523 K. However, at even higher temperatures, ethylene selectivity also drops, with the growth of butenes and a number of other compounds including BTX aromatics.Energies 2020, 13, x 8 of…”

Production of Gasolines and Monocyclic Aromatic Hydrocarbons: From Fossil Raw Materials to Green Processes

“…It has been considered that ESR can be realized using existing hydrocarbon steam reforming plants, provided that effective catalysts have been developed [146]. On the other hand, it has been shown that Ni/Ca aluminate commercial catalysts for natural gas steam reforming are excellent catalysts for ESR, too [147]. Raw bioethanol must be distilled to avoid additional catalyst deactivation by organic impurities [148].…”

Modeling of Laboratory Steam Methane Reforming and CO2 Methanation Reactors

“…Due to the intrinsic difficulties in implementing an automatic algorithm of minimization of the model error relative to the experimental data, the procedure adopted to perform the adjustment is a trial-and-error procedure. The full set of experimental data, collected in a wide range of operating conditions, used to perform the adjustment of the coefficients ζ 1 to ζ 6 , was reported and discussed in a companion paper [63]. Considering the full set of results, the error between simulated and experimental data was 8.6% with the HMMC catalyst, 11.8% with the 57-4Q catalyst and 9.7% with the 25-4Q catalyst [63].…”