Water-Gas Shift Reaction. Effect of Pressure on Rate over an Iron- Oxide-Chromium Oxide Catalyst.

Atwood, Kenton; Arnold, Mirko; Appel, E. G.

doi:10.1021/ie50488a038

Cited by 23 publications

(5 citation statements)

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“…A simple power dependence equation of the form P d (d being some constant) was found to be suitable. Other investigators also found that the reaction rate was dependent on the total pressure and used a similar functional form as that used in this investigation (Attwood et al, 1950;Moe, 1962).…”

Section: Reaction Ratesmentioning

confidence: 71%

Fischer−Tropsch Kinetic Studies with Cobalt−Manganese Oxide Catalysts

Keyser

Everson

Espinoza

1999

Ind. Eng. Chem. Res.

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An investigation was undertaken to establish the reaction mechanism for the Fischer-Tropsch reaction, in the presence of the water-gas shift reaction, over a cobalt-manganese oxide catalyst under conditions favoring the formation of gaseous, liquid, and solid (waxes) hydrocarbons (210-250 °C and 6-26 bar). A micro-fixed-bed reactor was used with a cobalt-manganese oxide catalyst prepared by a coprecipitation method. An integral reactor model involving both Fischer-Tropsch and water-gas shift reaction kinetics was used to describe the overall performance. Reaction rate equations based on Langmuir-Hinshelwood-Hougen-Watson models for the Fischer-Tropsch reaction (hydrocarbon forming) and empirical reaction rate equations for the water-gas shift reaction from the literature were tested. Different combinations of the reaction rate equation were evaluated with the aid of a nonlinear regression procedure. It was found that a reaction rate equation for the Fischer-Tropsch reaction based on the enolic theory performed slightly better than a reaction rate equation based on the carbide theory. Reaction rate constants for the cobalt-manganese oxide catalyst are reported, and it is concluded that this catalyst also behaves very much like iron-based catalysts.

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Section: Reaction Ratesmentioning

confidence: 71%

Fischer−Tropsch Kinetic Studies with Cobalt−Manganese Oxide Catalysts

Keyser

Everson

Espinoza

1999

Ind. Eng. Chem. Res.

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“…According to several studies, − the rate of reaction increases with the increase in pressure. Much of the high performance shown by the nanocatalysts when increasing the system pressure may be due to the greater availability of the interior of the active sites of the catalyst due to the rapid consumption of adsorbed fractions.…”

Section: Resultsmentioning

confidence: 99%

Effect of Multifunctional Nanocatalysts on n-C₇ Asphaltene Adsorption and Subsequent Oxidation under High-Pressure Conditions

et al. 2020

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This study was carried out to evaluate the effect of high pressure on the oxidation kinetics of n-heptane asphaltenes in the presence and absence of AuPd/Ce0.62Zr0.38O2 catalysts. Bimetallic Au–Pd catalysts with Au/Pd molar ratios from 3.5 to 9.6 were synthesized by deposition–precipitation of Au and followed by incipient wetness impregnation of Pd (3:1AuPd and 10:1AuPd). Adsorption isotherms between hydrocarbons and nanocatalysts were constructed varying the initial asphaltene concentration from 100 to 1500 mg·L–1. Subsequent oxidation was evaluated using thermogravimetric analysis under an air atmosphere, at different pressures from 0.084 to 6.0 MPa in a wide temperature range between 100 and 800 °C. Kinetic parameters were calculated using a first-order kinetic model, considering the system pressure. Adsorption affinity increases in the order support < 3:1AuPd < 10:1AuPd. The catalytic activity of the nanocatalyst was highly dependent on the employed temperature and pressure. Their presence reduces the n-C7 asphaltene decomposition temperature from 450 °C to temperatures below 200 °C for all catalysts used at 6.0 MPa. The main decomposition peaks are presented at 150, 170, and 210 °C for 10:1AuPd, 3:1AuPd, and support, at 6.0 MPa, respectively. Besides, the oxygen chemisorption (OC) region is favored as the material has a greater catalytic activity, increasing from 9.0 to 14.0% (on the load asphaltene basis calculation) for the support and 10:1AuPd catalyst. This was corroborated by the activation energy, which is reduced by more than 30% for all pressures evaluated with the best system. Besides, 89.0 and 80.0% of the mass are lost in the decomposition of the chemisorbed oxygen (DCO) thermal event for the 10:1AuPd and 3:1AuPd nanocatalysts, respectively. Finally, first and second combustions were carried out at temperatures below 240 °C at 6.0 MPa for the 10:1AuPd system, which is a very promising result to determine the reaction pathway for the heavy and extraheavy crude oils during EOR application.

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“…For both experiments and simulations, the amount of CO reduces as pressure increases; this indicates that the production of CO may be hindered by pressure or that the activity of the WGS catalyst is favored at higher pressures (Equation (2)). Given the stoichiometry of MSR (Equations (1)–(3)), a reduction of methane conversion and simultaneously CO generation as the pressure of the reactor increases is expected; at the same time, as reported by Atwood et al [ 37 ], the WGS reaction intensifies at higher pressures. These two mechanisms contribute to obtaining lower CO yields.…”

Section: Resultsmentioning

confidence: 62%

Integration of Methane Steam Reforming and Water Gas Shift Reaction in a Pd/Au/Pd-Based Catalytic Membrane Reactor for Process Intensification

Castro-Dominguez

Mardilovich

et al. 2016

Membranes

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Palladium-based catalytic membrane reactors (CMRs) effectively remove H2 to induce higher conversions in methane steam reforming (MSR) and water-gas-shift reactions (WGS). Within such a context, this work evaluates the technical performance of a novel CMR, which utilizes two catalysts in series, rather than one. In the process system under consideration, the first catalyst, confined within the shell side of the reactor, reforms methane with water yielding H2, CO and CO2. After reforming is completed, a second catalyst, positioned in series, reacts with CO and water through the WGS reaction yielding pure H2O, CO2 and H2. A tubular composite asymmetric Pd/Au/Pd membrane is situated throughout the reactor to continuously remove the produced H2 and induce higher methane and CO conversions while yielding ultrapure H2 and compressed CO2 ready for dehydration. Experimental results involving (i) a conventional packed bed reactor packed (PBR) for MSR, (ii) a PBR with five layers of two catalysts in series and (iii) a CMR with two layers of two catalysts in series are comparatively assessed and thoroughly characterized. Furthermore, a comprehensive 2D computational fluid dynamics (CFD) model was developed to explore further the features of the proposed configuration. The reaction was studied at different process intensification-relevant conditions, such as space velocities, temperatures, pressures and initial feed gas composition. Finally, it is demonstrated that the above CMR module, which was operated for 600 h, displays quite high H2 permeance and purity, high CH4 conversion levels and reduced CO yields.

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Water-Gas Shift Reaction. Effect of Pressure on Rate over an Iron- Oxide-Chromium Oxide Catalyst.

Cited by 23 publications

References 1 publication

Fischer−Tropsch Kinetic Studies with Cobalt−Manganese Oxide Catalysts

Fischer−Tropsch Kinetic Studies with Cobalt−Manganese Oxide Catalysts

Effect of Multifunctional Nanocatalysts on n-C₇ Asphaltene Adsorption and Subsequent Oxidation under High-Pressure Conditions

Integration of Methane Steam Reforming and Water Gas Shift Reaction in a Pd/Au/Pd-Based Catalytic Membrane Reactor for Process Intensification

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Water-Gas Shift Reaction. Effect of Pressure on Rate over an Iron- Oxide-Chromium Oxide Catalyst.

Cited by 23 publications

References 1 publication

Fischer−Tropsch Kinetic Studies with Cobalt−Manganese Oxide Catalysts

Fischer−Tropsch Kinetic Studies with Cobalt−Manganese Oxide Catalysts

Effect of Multifunctional Nanocatalysts on n-C7 Asphaltene Adsorption and Subsequent Oxidation under High-Pressure Conditions

Integration of Methane Steam Reforming and Water Gas Shift Reaction in a Pd/Au/Pd-Based Catalytic Membrane Reactor for Process Intensification

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Product

Resources

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Effect of Multifunctional Nanocatalysts on n-C₇ Asphaltene Adsorption and Subsequent Oxidation under High-Pressure Conditions