Mirella Virginie

Modelling of methane dry reforming over Ni/Al2O3 catalyst in a fixed-bed catalytic reactor

AbstractThe dry reforming of CH4 in a fixed-bed catalytic reactor for the production of hydrogen at different temperatures over supported Ni catalyst has been studied. In the simulation of the reactor, a one-dimensional heterogeneous model is applied. Temperature and concentration gradients are accounted for in the axial direction only. The reactor model for the dry reforming of methane used the Richardson and Paripatyadar kinetics and the Snoeck et al. kinetics for the coke-deposition and gasification reactions. The effect of using different temperatures on the performance of the reactor was analyzed. The amounts of each species consumed or/and produced were calculated and compared with the experimental determined ones. It was shown that the Richardson and Paripatyadar–Snoeck et al. kinetics gave a good fit and accurately predicted the experimental observed profiles from the fixed bed reactor, and thus the degree of conversion of CH4 and CO2.

Influence of copper and potassium on the structure and carbidisation of supported iron catalysts for Fischer–Tropsch synthesis

This paper addresses the effect of promotion with copper and potassium on the carbidisation kinetics, structure and performance of silica supported iron catalysts for high temperature Fischer–Tropsch synthesis. The promotion with copper and potassium results in the enhancement of iron dispersion. Small hematite nanoparticles were uncovered in the calcined iron catalysts. Activation of the calcined catalysts in carbon monoxide or syngas results in the reduction of hematite to magnetite at 250–300 °C. The magnetite is then carbidised into Hagg iron carbide. The promotion with copper and potassium affects the rate of the iron reduction and carbidisation. Copper strongly enhances both hematite reduction and magnetite carbidisation in carbon monoxide and syngas. The presence of potassium hinders reduction of hematite to magnetite. Much higher reaction rates were observed on copper-promoted catalysts than on the potassium-promoted and unpromoted counterparts while the promotion with potassium had a stronger impact on the selectivity.

Methane Dry Reforming over Ni-Co/Al2O3: Kinetic Modelling in a Catalytic Fixed-bed Reactor

Abstract The dry reforming of CH4 was investigated in a catalytic fixed-bed reactor to produce hydrogen at different temperatures over supported bimetallic Ni-Co catalyst. The reactor model for the dry reforming of methane used a set of kinetic models: The Zhang et al model for the dry reforming of methane (DRM); the Richardson-Paripatyadar model for the reverse water gas shift (RWGS); and the Snoeck et al kinetics for the coke-deposition and gasification reactions. The effect of temperatures on the performance of the reactor was studied. The amount of each species consumed or/and produced were calculated and compared with the experimental determined ones. It was showed that the set of kinetic model used in this work gave a good fit and accurately predict the experimental observed profiles from the fixed bed reactor. It was found that reaction-4 and reaction-5 could be neglected which could explain the fact that this catalyst coked rapidly comparatively with other catalyst. The use of large amount of Ni-Co will lead to carbon deposition and so to the catalyst deactivation.

Computational fluid dynamics study of the dry reforming of methane over Ni/Al 2 O 3 catalyst in a membrane reactor. Coke deposition

This work investigates the dry reforming of CH4 as an important process for the conversion of greenhouse gases to synthesis gas. The mixture of methane and CO2 is readily available in the greenhouse gas which makes realization of dry reforming of methane process more convenient. The paper is an attempt to numerically analyse by computational fluid dynamics (CFD) the coking and gasification mechanisms in the lab-scale membrane module with a fixed-bed supported nickel catalyst (Ni/Al2O3). The concentrations and molar fluxes obtained by the simulation are compared with the experimental profiles to validate the CFD model. It was found that working in a catalytic fixed-bed membrane reactor, in the case of the dry reforming of methane and under specific conditions, was not critical, from the point of view of catalyst deactivation.