Models Steam Reformer

Richardson JT, Lei M, Thrk B, Forester K, Twigg MV. Reduction of model steam reforming catalysts Ni0/a-Al203. Appl Catal A. 1994 110 217. 

Richardson, J. T., Turk, B. Twigg, M. V. (1996). Reduction of model steam reforming catalysts effect of oxide additives. Appl. Catal. A Gen., 148,97-112. 

The surface analyses of the Co/MgO catalyst for the steam reforming of naphthalene as a model compound of biomass tar were performed by TEM-EDS and XPS measurements. From TEM-EDS analysis, it was found that Co was supported on MgO not as particles but covering its surface in the case of 12 wt.% Co/MgO calcined at 873 K followed by reduction. XPS analysis results showed the existence of cobalt oxide on reduced catalyst, indicating that the reduction of Co/MgO by H2 was incomplete. In the steam reforming of naphthalene, film-like carbon and pyrolytic carbon were found to be deposited on the surface of catalyst by means of TPO and TEM-EDS analyses. 

A mechanistic model for propane steam reforming on a bimetallic Co-Ni catalyst in fluidized bed reactor... 

We have shown that the steam reforming of propane may be adequately described by LH mechanism involving different adsorption sites for steam and hydrocarbon. The associated model satisfied both statistical compliance and the BMV thermodynamic criterion. 

Steam reforming is a heterogeneously catalyzed process, with nickel catalyst deposited throughout a preformed porous support. It is empirically observed in the industry, that conversion is proportional to the geometric surface area of the catalyst particles, rather than the internal pore area. This suggests that the particle behaves as an egg-shell type, as if all the catalytic activity were confined to a thin layer at the external surface. It has been demonstrated by conventional reaction-diffusion particle modelling that this behaviour is due to... 

This study was carried out to simulate the 3D temperature field in and around the large steam reforming catalyst particles at the wall of a reformer tube, under various conditions (Dixon et al., 2003). We wanted to use this study with spherical catalyst particles to find an approach to incorporate thermal effects into the pellets, within reasonable constraints of computational effort and realism. This was our first look at the problem of bringing together CFD and heterogeneously catalyzed reactions. To have included species transport in the particles would have required a 3D diffusion-reaction model for each particle to be included in the flow simulation. The computational burden of this approach would have been very large. For the purposes of this first study, therefore, species transport was not incorporated in the model, and diffusion and mass transfer limitations were not directly represented. 

The CFD calculations of the present work used conditions and compositions from a Johnson Matthey detailed reformer model of a methanol plant steam reformer with upwards flow, at typical operating conditions. Conditions were chosen corresponding to three different axial positions along the tube, to reflect reaction rates typical of those close to the inlet, midway down the tube and close... 

The simulation of the thermal effects of the steam reforming reaction was based on a published reaction model (Hou and Hughes, 2001) for methane... 

Fig. 14 Mechanistic model for the carbon scavenging activity of stable Ni/La203 catalyst employed in the steam reforming of ethanol for H2 production.67...

Mann, Thurgood, and coworkers—Langmuir-Hinshelwood kinetic model for methanol steam reforming and WGS over Cu/Zn. Mann et al.335 published a complex Langmuir-Hinshelwood model for CuO/ZnO catalysts based on what one would encounter for a methanol steam reformer (MSR) for fuel cell applications. The water-gas shift rate, containing all MSR terms, was determined to be ... 

Takanabe, K., Aika, K.-i., Seshan, K., Lefferts, L., Sustainable hydrogen from biooil — Steam reforming of acetic acid as a model oxygenate, J. Catal., 2004, 227, 101. 

Arana et al. have performed extensive modeling and thermal characterization experiments on their reactor design. They modeled their design consisting of two suspended SiN - tubes linked with slabs of silicon using two-dimensional computation fluid dynamics and a heat transfer model (Femlab, Comsol Inc.). The heat of reaction of the steam reforming or... 

Table 6.1 lists the stoichiometric yields of hydrogen and percentage yields by weight from steam reforming of some representative model compounds present in biomass pyrolysis oils, and also several biomass and related materials. The table also shows the equilibrium yield of H2, as a percentage of the stoichiometric yield, predicted by thermodynamic calculations at 750 °C and vdth a steam-to-carbon (S/C) ratio of 5 [32]. 

Fio. 11. C3H6 oxidation under rich conditions showing model predictions for a model including total oxidation only and for one with both oxidation and steam reforming together. 

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