Kinetics of the high temperature water–gas shift over Fe2O3/ZrO2, Rh/ZrO2 and Rh/Fe2O3/ZrO2

Hakeem, Abrar A.; Berger, Rob J.; Kapteijn, Freek; Makkee, Michiel

doi:10.1016/j.cej.2014.10.104

Cited by 17 publications

(18 citation statements)

References 41 publications

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“…In this mechanism, the MnO 2 sites are reserved for ozone adsorption according to a classical ozone decomposition mechanism [27,28], whereas graphene offers sites for toluene adsorption. The L-H d mechanism has been commonly used to understand catalytic reactions [29][30][31][32]; however, to the best of our knowledge, no studies were reported on understanding catalytic ozonation of VOCs by the L-H d mechanism. 7 of 37 37 37 37 In this paper, we reported a kinetic study for catalytic ozonation of toluene over MnO 2 /graphene.…”

Section: Introductionmentioning

confidence: 93%

Novel mechanistic view of catalytic ozonation of gaseous toluene by dual-site kinetic modelling

Yao

Hui

et al. 2017

Chemical Engineering Journal

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This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. AbstractThe catalytic ozonation of VOCs is a promising approach for degradation of indoor VOCs, such as gaseous toluene. However, the mechanism and relevant kinetic steps involved in this reaction remain unclear. In this study, the catalytic ozonation of toluene over MnO 2 /graphene was investigated using the empirical power law model and classic Langmuir-Hinshelwood single-site (denoted as L-H s ) mechanism. The apparent activation energy determined using the power law model was 29.3±2.5 kJ mol −1 . This finding indicated that the catalytic ozonation of toluene over MnO 2 /graphene was a heterogeneous reaction, and the Langmuir-Hinshelwood mechanism was applicable. However, the L-H s mechanism did not fit the experimental data, suggesting that the reaction was non-single-site governed. A novel Langmuir-Hinshelwood dual-site (denoted as L-H d ) mechanism was then proposed to explain the experimental observations of the catalytic ozonation of toluene over MnO 2 /graphene through a steady-state kinetic study. This mechanism was based on the hypothesis that MnO 2 was responsible for ozone decomposition and toluene adsorption on graphene; these two types of adsorption were coupled by an adjacent attack. Furthermore, XPS results confirmed the presence of a strong connection between MnO 2 and graphene sites on the surface of MnO 2 /graphene. This connection allowed the adjacent attack and validated the dual-site mechanism. The L-H d model was consistent with the predicted reaction rate of toluene removal with a correlation coefficient near unity (r 2 = 0.9165). Moreover, the physical criterion was in accordance with both enthalpy and entropy of toluene adsorption constraints. Fulfillment of mathematical and physical criteria indicated the catalytic ozonation of toluene over MnO 2 /graphene can be well described by the L-H d mechanism. This study helps understand the catalytic ozonation of toluene over MnO 2 /graphene in a closely mechanistic view.

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Section: Introductionmentioning

confidence: 93%

Novel mechanistic view of catalytic ozonation of gaseous toluene by dual-site kinetic modelling

Yao

Hui

et al. 2017

Chemical Engineering Journal

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“…Compared to the values found in literature, these results are significantly lower. The lowest activation energy for the water-gas shift reaction was 70 kJ/mol [2,[17][18][19], which is 1.24 times higher than the one obtained in the fluidized bed TGA.…”

mentioning

confidence: 54%

Innovative Microreactors for Low-grade Feedstock Gasification

Samih¹,

Farag²,

Chaouki³

2018

Gasification for Low-Grade Feedstock

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The first fluidized bed thermogravimetric analyzer (FBTGA) has been developed. The proof of concept of the FBTGA has been carried out on the thermal decomposition of calcium hydroxide. The kinetics and modeling of coal pyrolysis and gasification were investigated in the FBTGA. The obtained activation energies for the individual gases that are produced from coal pyrolysis are 19 to 21% lower than those found for similar coals in the literature. This decrease in the activation energies is explained by a temperature gradient of 185 to 209°C. For the CO shift reaction, the resulting activation energy is 46.6 kcal/ mol, increasing by 20% from the one used in the literature. The second reactor presented in this work is a TGA powered by electromagnetic irradiation. As an application for this reactor, a novel kinetic model based on a dual attempt to predict not only the yield but also the composition of bio-oil is presented. The validation of the developed models demonstrated an excellent capability of predicting the yield and quality of the produced oil. The third reactor is a saddle reactor, which consists of two V-shaped pairs of arms and minimizes the impact of the heat and mass transfer limitation on chemical reactions.

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“…This is a different approach where the kinetic equations have different denominatora for the rate equations of the rWGS reaction and methanation reactions as a consequence of the reaction mechanisms being developed separately for each reaction. The reaction mechanisms for Hakeem et al, 8 and Alstrup 17 and Weatherbee 18 are found in the Supporting Information Table S1 and Table S2, respectively. The Arrhenius and van't Hoff equations were applied to calculate the temperature dependency of rate constants and adsorption equilibrium constants of the models.…”

Section: Experimental Partmentioning

confidence: 99%

Catalyst Screening and Kinetic Modeling for CO Production by High Pressure and Temperature Reverse Water Gas Shift for Fischer–Tropsch Applications

Vázquez

Pfeifer

Lehtonen

et al. 2017

Ind. Eng. Chem. Res.

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In this work, catalyst screening and reaction kinetic modeling are performed for two Ni-based and one Rh-based commercial catalysts for a reverse water gas shift (rWGS) reaction under atmospheric and 30 bara pressure. Ni-based catalysts displayed higher activity compared to Rh-based catalysts despite the severe initial deactivation Ni-based catalysts suffered, which increases catalyst selectivity toward CO formation. Ni/Al2O3 catalyst with lower Ni content (2 w-%) exhibited higher selectivity toward CO formation compared to the Ni/Al2O3 catalyst with higher Ni content (15 wt %). The Ni/Al2O3 (2 wt % of Ni) catalyst was further tested for kinetic modeling. Three kinetic models were developed based on reaction mechanisms and kinetic models obtained from other publications for rWGS/WGS, methanation, and methane steam reforming reactions based on different mechanistic approaches. The model based on mechanistic assumptions originally proposed by Xu and Froment was concluded to be the most suitable to describe the high temperature reaction system of the rWGS and methanation over supported nickel catalyst. On the basis of statistical analysis, the model proposed by Xu and Froment was also concluded to be the best for the catalyst and reaction system studied in this work.

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Kinetics of the high temperature water–gas shift over Fe2O3/ZrO2, Rh/ZrO2 and Rh/Fe2O3/ZrO2

Cited by 17 publications

References 41 publications

Novel mechanistic view of catalytic ozonation of gaseous toluene by dual-site kinetic modelling

Novel mechanistic view of catalytic ozonation of gaseous toluene by dual-site kinetic modelling

Innovative Microreactors for Low-grade Feedstock Gasification

Catalyst Screening and Kinetic Modeling for CO Production by High Pressure and Temperature Reverse Water Gas Shift for Fischer–Tropsch Applications

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