Evaluation of an in situ spatial resolution instrument for fixed beds through the assessment of the invasiveness of probes and a comparison with a micro-kinetic model

Touitou, Jamal; Aiouache, Farid; Burch, Robbie; Douglas, Roy; Hardacre, Christopher; Morgan, Kevin T.; Sawka‐Dobrowolska, W.; Stewart, C.; Stewart, Jonathan; Goguet, Alexandre

doi:10.1016/j.jcat.2014.09.006

Cited by 23 publications

(30 citation statements)

References 60 publications

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“…Data accuracy is affected by influences of quite different origin, including the uncertainty inherent to IR microimaging as discussed in the previous section. Additionally, the distribution of catalytically active Pt on the individual particles prepared by the chosen method is not necessarily completely homogenous, resulting in differences in the catalytic activity of individual particles.…”

Section: Methodsmentioning

confidence: 99%

“…The exploration of the diffusion pathways of the molecules involved in the reactions and of the location of their mutual conversion is, correspondingly, quite a complex task. It has given rise to the development of a spectrum of techniques, including the in‐situ observation of chemical conversion in the bed of catalyst particles, and the ex‐situ observation by, e. g., flux response technology (FRT) and temporal analysis of products (TAP) dealing with this complexity and offering the option of (model‐based) predications on both transport and conversion phenomena within the catalyst…”

Section: Introductionmentioning

confidence: 99%

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One‐Shot Measurement of Effectiveness Factors of Chemical Conversion in Porous Catalysts

et al. 2018

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From the earliest days of heterogeneous catalysis, high surface area solids were extensively used for attaining largest possible densities of active sites and, correspondingly, for maximizing turnover. Since sites are active in the real sense of the word only if they are occupied by reactants, i. e., by molecules still to be converted, the relative fraction of pore volume occupied by reactants (the “effectiveness factor”) is a key number for the efficiency of a catalyst in a given reaction. Its determination, so far generally based on reaction rate measurements with purposefully varied catalyst particles, remained to date a challenging task since it must be based on additional assumptions. The “one‐shot determination” of effectiveness factors by IR microimaging, here exemplified on considering the catalytic hydrogenation of benzene to cyclohexane by platinum dispersed on nanoporous glass, is shown to open up a promising route to overcome these limitations.

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Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

One‐Shot Measurement of Effectiveness Factors of Chemical Conversion in Porous Catalysts

et al. 2018

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“…Particularly when using complex reactant mixtures it is critical that an in-depth understanding of the mechanisms and kinetics of surface reactions is obtained. 6 As such, experimental measure- [180][181][182] Despite the proven potential of operando techniques for identifying catalytically active species/centres/phases and for elucidating reaction mechanisms, they typically fail to provide a molecular picture of catalytic reactions including microkinetics because of low time resolution, i.e. in many processes there are short lived intermediates which may not be detected due to incompatible time resolutions.…”

Section: Tap Relevance In Current Catalyst Researchmentioning

confidence: 99%

“…A further benefit of the utilization of operando spatially resolved techniques has been the ability to utilize experimentally derived data to improve numerical analysis/predictions, including microkinetic models. 6,182 While TAP has readily contributed to the bridging of the material and pressure gaps, there is now the potential for TAP to assist with the knowledge gap 6,212 that exists between experiment and kinetic modelling. An important issue, which is rarely tackled in transient kinetic analysis, is the relevance of unsteady-state kinetics for predicting steady-state catalyst performance.…”

Section: Ambitions For Future Development Of Tapmentioning

confidence: 99%

Forty years of temporal analysis of products

Morgan

Maguire

Fushimi

et al. 2017

Catal. Sci. Technol.

131

101

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A detailed understanding of reaction mechanisms and kinetics is required in order to develop and optimize catalysts and catalytic processes. While steady-state investigations are known to give a global view of the catalytic system, transient studies are invaluable since they can provide more comprehensive insight into elementary steps. For almost forty years temporal analysis of products (TAP) has been successfully utilized for transient studies of gas phase heterogeneous reactions, and there have been a number of advances in instrumentation and numerical modeling methods in that time. Since TAP is a complex methodology it is often viewed as a niche specialty. With the purpose to make TAP more relevant and approachable to a wider segment of the catalytic research community, part of the intention of this work is to highlight the significant contributions TAP has made to elucidating mechanistic and kinetic aspects of complex, multistep heterogeneous reactions. With this in mind, an outlook is also disclosed for the technique in terms of what is needed to revitalize the field and make it more applicable to the recent advances in catalyst characterization (e.g. operando modes).

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“…Jamal Touitou et al reported several techniques of in situ monitoring of catalyst beds. 21,22) They used a glass tube equipped with a fine thermocouple inside of it. The glass tube was inserted through the packed bed parallel to the reaction gas flow.…”

Section: Introductionmentioning

confidence: 99%

<i>In Situ</i> Temperature Measurement of Sinter Beds at High Spatial and Time Resolution

Taira

Matsumura

2018

ISIJ Int.

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In the sintering process during iron making, the sintering reaction proceeds in a packed bed along with the combustion of coke particles. Although detailed temperature information is necessary to improve the process, it is difficult to measure the temperature distribution inside the packed bed with high spatial and time resolution. We performed in situ temperature measurement inside the sinter bed at high spatial and time resolution, i.e., 2 mm and 10 s, respectively, during sintering. A sheathed thermocouple was scanned at optimized scan speed along the inside of the thin-wall alumina tube which was held perpendicular inside the sinter bed. The information on the temperature variation during sintering showed a clear correlation between the quality of the sinter and the sinter heat pattern for each layer. Further analysis also showed that the flame front speed is proportional to the O 2 consumption in the sinter bed. The temperature measurement technique enabled an unprecedented detailed discussion with the temperature distribution inside the sinter bed during sintering. This technique will not only help to improve the sintering process but also provide beneficial information on the chemical reactions occurring inside packed beds.

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Evaluation of an in situ spatial resolution instrument for fixed beds through the assessment of the invasiveness of probes and a comparison with a micro-kinetic model

Abstract: Evaluation of an in situ spatial resolution instrument for fixed beds through the assessment of the invasiveness of probes and a comparison with a micro kinetic model.

Cited by 23 publications

References 60 publications

One‐Shot Measurement of Effectiveness Factors of Chemical Conversion in Porous Catalysts

One‐Shot Measurement of Effectiveness Factors of Chemical Conversion in Porous Catalysts

Forty years of temporal analysis of products

<i>In Situ</i> Temperature Measurement of Sinter Beds at High Spatial and Time Resolution

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