NMR imaging of mass transport and related phenomena in porous catalysts and sorbents

Koptyug, Igor V.; Khitrina, Ludmila Yu.; Parmon, Valentin N.; Sagdeev, R. Z.

doi:10.1016/s0730-725x(01)00286-7

Cited by 23 publications

(17 citation statements)

References 10 publications

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“…Codd and Altobelli showed, in their case study on glass spheres with a diameter of 300–500 μm, that diffusion and flow measurements by NMR can facilitate the investigation of porous structures. Their work confirmed that a global gas propagator analysis yields structural information for a chosen observation time , , . Lysova et al and Koptyug et al performed NMR measurements for studying structured catalysts and related transport phenomena in liquids and gases.…”

Section: Introductionmentioning

confidence: 76%

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Spatially Resolved Characterization of the Gas Propagator in Monolithic Structured Catalysts Using NMR Diffusiometry

et al. 2018

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Gas diffusivity measurements in opaque porous media were performed using nuclear magnetic resonance. An optimized pulsed-field gradient stimulated echo method with free volume selection was used to investigate the propagator of thermally polarized methane gas within commercial monolithic catalyst supports. Since signal losses due to T 2 relaxation were minimized by using a short echo time, diffusion processes could be characterized by the measured propagator functions and effective diffusion coefficients were determined for a broad range of observation times and in different spatial directions. The study of this noninvasive characterization of gas diffusion found a clear effect of the monolith type and its pore size and coating on the effective gas diffusion coefficient and the apparent tortuosity for a given observation time.

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Section: Introductionmentioning

confidence: 76%

“…Recently, some NMR‐based morphological studies of regular and irregular monolithic structures have been reported . Grosse et al investigated the porosity, pore size distribution, and other properties of heterogeneous structures.…”

Section: Introductionmentioning

confidence: 99%

Spatially Resolved Characterization of the Gas Propagator in Monolithic Structured Catalysts Using NMR Diffusiometry

et al. 2018

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“…2). The one-dimensional profiles of adsorbed water distribution along the axis of the cylindrical tablet and their temporal transformations were detected using the single point imaging technique (SPI) as described in detail elsewhere [16,21]. The spatial resolution in these experiments was 50-70 lm which is sufficient for the detection of such profiles if layer thickness exceeds 1 mm.…”

Section: Studies Of Mass Transportmentioning

confidence: 99%

A compact layer of alumina modified by CaCl2: The influence of composition and porous structure on water transport

Glaznev

Koptyug

Aristov

2010

Microporous and Mesoporous Materials

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“…Some other possible applications that can be useful for catalysis and related disciplines are the drying of porous materials [29][30][31] (including contact drying, external mass transfer across the fluid/solid interface), adsorption [29,31,32] (including sorption of water vapor and adsorption of gases by various porous sorbents), and the in situ visualization of supported catalyst preparation [33].…”

Section: Coupling Of Mass Transport and Chemical Reactionmentioning

confidence: 99%

NMR imaging of mass transport processes and catalytic reactions

et al. 2005

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c Boreskov Institute of Catalysis, 5 Acad. Lavrentiev Pr., Novosibirsk 630090, Russia NMR imaging and spectroscopy techniques are applied to study flow and filtration of liquids, gases and granular solids in various geometries and to the in situ studies of the interplay of mass transport and catalytic reactions in porous media. In particular, quantitative spatially resolved maps of flow velocities of liquids and gases in the channels of monoliths have been obtained. A comparative study of the filtration of water and propane through model porous media has revealed that the dispersion coefficients for water are dominated by the holdup effects even in a bed of nonporous glass beads. Similar experiments performed with the gravity driven flow of liquid-containing fine solid particles through a porous bed have yielded the distributions of particle velocities for various flow rates. The NMR imaging technique was employed to visualize the propagation of autocatalytic waves for the Belousov-Zhabotinsky reaction carried out in a model porous medium. It was demonstrated that the wave propagation velocity decreases as the wave crosses the boundary between the bulk liquid and the flooded bead pack. The images detected during the catalytic hydrogenation of a-methylstyrene on a single catalyst pellet at elevated temperatures have revealed that the reaction and the accompanying phase transition alter the distribution of the liquid phase within the pellet.

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NMR imaging of mass transport and related phenomena in porous catalysts and sorbents

Cited by 23 publications

References 10 publications

Spatially Resolved Characterization of the Gas Propagator in Monolithic Structured Catalysts Using NMR Diffusiometry

Spatially Resolved Characterization of the Gas Propagator in Monolithic Structured Catalysts Using NMR Diffusiometry

A compact layer of alumina modified by CaCl2: The influence of composition and porous structure on water transport

NMR imaging of mass transport processes and catalytic reactions

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