Applications of NMR tomography to mass transfer studies

Koptyug, Igor V.; Sagdeev, R. Z.

doi:10.1070/rc2002v071n10abeh000743

Cited by 28 publications

(28 citation statements)

References 296 publications

(646 reference statements)

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…MRI provides a whole range of approaches for studying flow and dispersion of fluids in model reactors [2]. As a representative example, we present an MRI study of the hydrodynamics of water inflowing into the transport channels of a monolithic catalyst.…”

Section: Flow Of Liquids and Gasesmentioning

confidence: 99%

“…The nuclear magnetic resonance imaging (MRI) technique is well known for its ability to visualize the internal structure of various liquid-containing objects, from humans to catalyst pellets and prewetted rock cores [1][2][3]. It is important, however, that image contrast in MRI is governed not only by the structural characteristics of an object under study, but also by a broad range of its other properties and the processes within it.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

NMR imaging of mass transport processes and catalytic reactions

et al. 2005

View full text Add to dashboard Cite

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.

show abstract

Section: Flow Of Liquids and Gasesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

NMR imaging of mass transport processes and catalytic reactions

et al. 2005

View full text Add to dashboard Cite

show abstract

“…Materials with biporous structure are widely applied in the industry. Therefore, the study of the specific features of the translational mobility of molecules in such systems is a rather urgent task [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

Pseudo-Restricted Self-Diffusion of Molecules in Biporous Structures: Study by Pulsed Field Gradient NMR

Kortunov

Skirda

2005

Colloid J

View full text Add to dashboard Cite

The mobility of liquid ( n -decane) that fills the system of primary and secondary pores of a biporous sample (granular Vycor porous glass) is studied by the pulsed field gradient NMR technique. The anomalous time dependence of the slow component of diffusion decay is revealed: the self-diffusion coefficient decreases with an increase in diffusion time t d and, at large t d values, this dependence satisfies the feature of completely restricted self-diffusion. It is established that this component is related to the mobility of liquid molecules filling the system of primary pores. By use of computer simulation, it is shown that the effect of "pseudo-restricted" diffusion is explained by the exchange processes between the phases, where the molecules of the liquid that are present in the systems of primary and secondary pores and differ in self-diffusion coefficients are understood as the phases. The effect of interfacial exchange is confirmed by the time dependence of the fraction of molecules with the lowest self-diffusion coefficients. The revealed phenomenon of "pseudo-restricted" diffusion is not related to real spatial constraints and can be observed in any systems with two (or more) phases with different self-diffusion coefficients, provided that these "phases" are bulky and can be subjected to molecular exchange.

show abstract

“…For the determination of spatial moisture distributions inside the specimens, made from building materials, traditional weight methods with the cutting of the test specimen into pieces are often used. Now there are modern methods of nondestructive testing: nuclear magnetic resonance [4], game scope [2], neutron radiography, computed tomography and x-rays [3]. However, the methods are not able to carry out non-destructive testing of finished products as it is necessary to have samples of a given configuration, and the measurement process is characterized by a significant duration, which does not allow to obtain a rapid information of the products quality.…”

Section: Introductionmentioning

confidence: 99%

Non-destructive testing method for determining the solvent diffusion coefficient in the porous materials products

Belyaev

Mishchenko

Belyaev

2018

J. Phys.: Conf. Ser.

View full text Add to dashboard Cite

Abstract. Ensuring non-destructive testing of products in industry is an urgent task. Most of the modern methods for determining the diffusion coefficient in porous materials have been developed for bodies of a given configuration and size. This leads to the need for finished products destruction to make experimental samples from them. The purpose of this study is the development of a dynamic method that allows operatively determine the diffusion coefficient in finished products from porous materials without destroying them. The method is designed to investigate the solvents diffusion coefficient in building constructions from materials having a porous structure: brick, concrete and aerated concrete, gypsum, cement, gypsum or silicate solutions, gas silicate blocks, heat insulators, etc. A mathematical model of the method is constructed. The influence of the design and measuring device operating parameters on the method accuracy is studied. The application results of the developed method for structural porous products are presented.

show abstract

Applications of NMR tomography to mass transfer studies

Cited by 28 publications

References 296 publications

NMR imaging of mass transport processes and catalytic reactions

NMR imaging of mass transport processes and catalytic reactions

Pseudo-Restricted Self-Diffusion of Molecules in Biporous Structures: Study by Pulsed Field Gradient NMR

Non-destructive testing method for determining the solvent diffusion coefficient in the porous materials products

Contact Info

Product

Resources

About