Structuring zeolite bodies for enhanced heat-transfer properties

Borchardt, Lars; Michels, Nina‐Luisa; Nowak, Torsten; Mitchell, Sharon; Pérez‐Ramírez, Javier

doi:10.1016/j.micromeso.2015.01.028

Cited by 17 publications

(11 citation statements)

References 36 publications

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“…S TRUCTURED catalyst has been extensively studied these years as they have been recognized as one of the most promising candidates for environment applications due to its attractive properties, such as high thermal conductivity, superior mass/heat transfer characteristics, and low pressure drop. [1][2][3] Along with the increased interest in structured catalysts, as one branch of this family, zeolite structured catalyst has gained intense attentions for its widely applications in the selective catalytic reduction in NO x , 4 disproportionation of toluene, 5 methanol to olefins, 6 etc. Particularly, the HZSM-5 (typical MFI) showed excellent shape selectivity and acid properties, 7 which make it a popular choice for designing zeolite structured catalyst.…”

Section: Introductionmentioning

confidence: 99%

Preparation and Performances of Hierarchical Structured HZSM‐5 Washcoating on Stainless‐Steel Substrates

et al. 2016

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The washcoats of the hierarchical HZSM‐5 zeolite (through desilication) were prepared on the inner surface of SS304 stainless‐steel tubes. The properties of slurries and coatings were characterized by analysis of particle size, measurements of rheological property, loading, adhesion, and finally the catalytic cracking test. It was found that introducing mesoporosity on the zeolite crystals was beneficial for reducing the particle size during ball milling for slurries preparation, which was helpful for improving loading due to a significant change in the rheological property. As the interaction between the particles with different sizes was enhanced after ball milling, the adhesion of the prepared coatings was improved. The catalytic activity and stability of the hierarchical HZSM‐5 coatings for the catalytic cracking of n‐dodecane were 56% and 75% higher than that of the conventional one, respectively. This probably resulted from the enhanced diffusion rate of reactant and products in the crystals and the coatings.

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Section: Introductionmentioning

confidence: 99%

Preparation and Performances of Hierarchical Structured HZSM‐5 Washcoating on Stainless‐Steel Substrates

et al. 2016

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“…Tables S1 and S2 list the model parameters and material properties used in these simulations. The value of the thermal conductivity of the zeolite 13X coating of 0.15 W m –1 K –1 was in the middle of the range found in the literature. ,− The ranges of thermal conductivities of the gases listed in Table S2 spanned the temperature ranges predicted by COMSOL during the simulations; COMSOL also produced these values from its physical properties library. Table S3 provides a summary of all 24 runs, including the conditions and resulting k eff for each one.…”

Section: Resultsmentioning

confidence: 99%

“…In contrast, Tatarchuk − reported values of about 1 to 9 W m –1 K –1 for his microfibrous materials, depending on the metal fiber used. Compare these values with the sometimes much lower values of typical packed beds, which range from a low of about 0.06 W m –1 K –1 for zeolite crystals to an unusual high of about 19 W m –1 K –1 for silica gel-graphite composite bricks, with typical values of around 0.1 to 0.7 W m –1 K –1 . − These low values for packed beds of spheres, pellets, or granules stem from the fact that the thermal conductivity of a packed bed is generally controlled by the thermal conductivity of the gas phase, due to only point contacts existing between the far more thermally conductive solid adsorbent material …”

Section: Introductionmentioning

confidence: 87%

Effective Radial Thermal Conductivity of a Parallel Channel Corrugated Metal Structured Adsorbent

Amalraj

Ebner

Ritter

2019

Ind. Eng. Chem. Res.

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The effective radial thermal conductivity (k eff ) of a 2-D analog of a 3-D, parallel channel, corrugated metal, structured adsorbent bed was studied using COMSOL Multiphysics. This 2-D structure consisted of alternating sections of corrugated and flat metal foil sheets, with k eff predicted in 1-D perpendicular to the flat metal foil sheet, i.e., the radial direction in a 3-D cylindrical bed. The effect of the thickness of zeolite coating, thickness of metal, type of metal, type of contact between the metal foil sheets (i.e., metal-to-metal, coating-to-coating and metal-to-coating point contacts, and metal-to-metal imbedded contacts), air gap size between the corrugated and flat metal foil sheets, coating on just one or both sides of the metal foil sheets, alignment of the corrugation between sections, and type of stagnant gas medium on k eff was studied. In all cases, temperature contour plots revealed the minute region around the point contacts, being mostly stagnant gas medium, manifested a significant resistance to thermal conductivity, with the imbedded contacts minimizing the effect. The parametric study revealed direct metal-to-metal contact had the most positive effect on k eff , whether being a point or imbedded contact: k eff respectively varied between 0.561 and 0.726 W m −1 K −1 for SS and 6.66 W m −1 K −1 for Al, showing strong dependence on the metal conductivity and weak dependence on the gas medium and all other parameters. When the corrugated and flat metal foil sheets were either coated with zeolite or separated by an air gap, k eff was significantly reduced, varying between 0.090 and 0.125 W m −1 K −1 in air for SS or Al; k eff also depended strongly on the gas medium but only weakly on the metal conductivity and all other parameters.

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“…This behavior is due to better contact between zeolite and support as well as the dense nature of the coating layer. The measured value shows an agreement with the reported effective thermal conductivity of zeolites as pelletized form, where an increase of effective thermal conductivity is obtained by increasing the packing density , , . However, the two types of zeolites prepared by the same coating method show slight differences in their thermal conductivity values.…”

Section: Resultsmentioning

confidence: 99%

Heat and Mass Transfer Properties of Zeolite Coatings: Comparison of Reactive‐ and Spray‐Coated Systems

Chanda

Wang

Schwieger

2018

Chemie Ingenieur Technik

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Coated materials are widely used in the process industry. For the generation of adsorption heat exchangers for heat pumps, coated systems offer compactness, robustness as well as high performance. The heat and mass transfer properties into and through functional coating layers play a prominent role in the overall performance of the whole coated systems. In this contribution, laser flash analysis and sorption measurement methods are applied to compare the heat and mass transfer properties of the common spray coating and reactive coating. The experimental results indicate that the reactive coating technique leads to layers with better heat transfer properties and in contrast to lower mass transfer.

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Structuring zeolite bodies for enhanced heat-transfer properties

Cited by 17 publications

References 36 publications

Preparation and Performances of Hierarchical Structured HZSM‐5 Washcoating on Stainless‐Steel Substrates

Preparation and Performances of Hierarchical Structured HZSM‐5 Washcoating on Stainless‐Steel Substrates

Effective Radial Thermal Conductivity of a Parallel Channel Corrugated Metal Structured Adsorbent

Heat and Mass Transfer Properties of Zeolite Coatings: Comparison of Reactive‐ and Spray‐Coated Systems

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