Modeling of Gas Adsorption Process of a Single Pellet

A commercial zeolite pellet is formed by binding large numbers of small crystals with microporous material. Its Micro-structure has great affects on the gas adsorption process. In this paper, the physical and mathematic models of the adsorption process for a single pellet are established. The N2 adsorption properties in a 5A zeolite pellet are studied. Very detailed results of intra-pellet adsorption process are obtained. The impacts of crystal size, pellet porosity, diffusion coefficient of the binding materials and crystals on the adsorption rate are studied.

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Modeling of Nitrogen Adsorption Process in a 5A Zeolite Pellet

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.560-561.73 ◽

2012 ◽

Vol 560-561 ◽

pp. 73-78

Author(s):

Xiang Jun Liu ◽

Dan Li Wang

Keyword(s):

Nitrogen Adsorption ◽

Adsorption Properties ◽

Physical Models ◽

Nitrogen Diffusion ◽

Micro Structure ◽

Microporous Material ◽

Large Numbers ◽

Small Crystals ◽

Crystal Fraction ◽

5A Zeolite

A zeolite pellet is formed by binding large numbers of small crystals with microporous material. The adsorption properties of a zeolite pellet depend on its micro-structure. In this paper, two physical models of a 5A zeolite pellet with the crystals dispersed or clustered are established. Mathematical models to describe nitrogen diffusion and adsorption occurred inside the pellet are proposed. The N2adsorption properties on pellets with different micro-structure are compared. Very detailed results regarding the effects of the crystal fraction, crystal distribution are revealed.

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Studying the Effects of Adsorption Heat on Nitrogen Adsorption in a Single Pellet

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.516-517.218 ◽

2012 ◽

Vol 516-517 ◽

pp. 218-223

Author(s):

Xiang Jun Liu ◽

Dan Li Wang ◽

Ying Shu Liu

Keyword(s):

Thermal Conditions ◽

Nitrogen Adsorption ◽

Heat Transfer Process ◽

Adsorption Heat ◽

Adiabatic Process ◽

N2 Adsorption ◽

Single Pellet ◽

5A Zeolite ◽

Adsorption Processes ◽

Mass And Heat Transfer

A physical model of a 5A zeolite pellet considering its micro-structure is established. Mathematical models to describe the mass and heat transfer process occurred inside the pellet are proposed. Two adsorption processes, including an isothermal and an adiabatic process are comparatively studied. The N2 adsorption properties on 5A zeolite pellet at different thermal conditions are compared. The effects of adsorption heat on adsorption capacity, adsorption rate and adsorbent equilibrium time are revealed.

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Two Coordination Polymers Constructed from Pentanuclear Zinc Clusters with Triazolate and Benzenecarboxylate Ligands: Selective Gas Adsorption

Australian Journal of Chemistry ◽

10.1071/ch17498 ◽

2018 ◽

Vol 71 (3) ◽

pp. 111 ◽

Cited By ~ 6

Author(s):

Wen-Wen Zhang ◽

Yu-Ling Wang ◽

Ying Liu ◽

Qing-Yan Liu

Keyword(s):

Porous Structure ◽

Coordination Polymers ◽

Gas Adsorption ◽

3D Structure ◽

Co2 Uptake ◽

N2 Adsorption ◽

Carboxylate Oxygen ◽

Zinc Clusters ◽

Solvent Molecules ◽

3D Framework

Reactions of Zn(NO3)2·6H2O with 1,2,4-triazole (Htrz) and 1,3,5-benzenetricarboxylic acid (H3BTC) or 5-sulfoisophthalic acid (5-H3SIP) afforded two coordination polymers, {[Zn5(μ3-OH)2(trz)2(BTC)2(DMF)2]·x(solvent)}n (1) and {[Zn7(trz)8(5-SIP)2(H2O)4]·4(H2O)}n (2). Compound 1 has pentanuclear [Zn5(μ3-OH)2] clusters, which are linked by the triazolate ligands to give a 2D layer. The 2D layer is further bridged by BTC3− ligands to form a 3D framework. The 3D framework of 1 has 1D channels filled by solvent molecules. Desolvated 1 shows a moderate CO2 uptake and high CO2/CH4 and CO2/N2 adsorption selectivities due to its carboxylate oxygen decorated pore environment. Compound 2 contains a rare 3D zinc-triazolate framework constructed from a pentanuclear [Zn5(trz)8] cluster wherein the five zinc atoms are arranged linearly. The 3D zinc-triazolate substructure has 1D open channels filled by 5-SIP3− ligands, which interact with the zinc-triazolate framework through Zn–O bonds, leading to a non-porous 3D structure of 2. Introduction of BTC3− into the zinc-triazolate system gave the porous structure of 1. While a variation of BTC3−, 5-SIP3− was introduced into the zinc-triazolate system yielding a non-porous structure of 2, demonstrating that the secondary ligands play an important role in the formation of the final structures.

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Study on Chlorinated Gas Adsorption Using Activated Carbon via Polyvinyl Chloride (PVC) Stepwise Pyrolysis Process

Proceedings ◽

10.3390/proceedings2201314 ◽

2018 ◽

Vol 2 (20) ◽

pp. 1314

Author(s):

Patiparn Boonruam ◽

Piyachat Wattanachai ◽

Settakorn Upasen

Keyword(s):

Activated Carbon ◽

Polyvinyl Chloride ◽

Adsorption Process ◽

Gas Adsorption ◽

Chloride Ion ◽

Pyrolysis Process ◽

Acid Base ◽

Surface Areas ◽

Acid Base Titration ◽

Specific Surface Areas

In this research, we studied the chlorinated gas adsorption process using activated carbon. Two types of granular activated carbon were employed: GAC800 and GAC1200; with specific surface areas of 800 m2/g and 1200 m2/g, respectively. In order to optimize the polyvinyl chloride (PVC) dehydrochlorination conditions, three parameters were studied: (i) the type of precursor—PVC and PVC mixed with charcoal (1:1 by weight)—(ii) the temperature—300 and 400 °C—and (iii) the retention time—30, 120, and 240 min. Mohr’s method and acid-base titration were used to estimate the captured amount of chlorinated gas. The results indicated that the PVC dehydrochlorination occurred completely about 69–73 wt.% at 400 °C for 240 min. The amount of chloride ion was detected around 1–2 mmol/LNaOH. The estimated HCl adsorption capacity for the GAC800 and GAC1200 samples potentially absorbed 0.27 mgHCl/gGAC and 0.21 mgHCl/gGAC, respectively. In addition, the efficiency for GAC800 and GAC1200 was reported to 37.95% and 28.92%, respectively.

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Fabrics of Icing-Mound and Pingo Ice in Permafrost

Journal of Glaciology ◽

10.1017/s0022143000020967 ◽

1978 ◽

Vol 20 (84) ◽

pp. 563-569 ◽

Cited By ~ 7

Author(s):

W. Alan Gell

Keyword(s):

Active Layer ◽

Crystal Size ◽

Early Growth ◽

Bulk Water ◽

Freezing Rate ◽

Lattice Orientation ◽

Small Crystals ◽

Freezing Direction

Abstract Crystallization histories of some ice layers in permafrost are inferred from crystal size, shape, dimensional and lattice orientation, and inclusion patterns. In an icing mound, formed by injection of water beneath frozen active-layer soil, early growth was rapid, indicated by copious small crystals and bubbles, followed by slower growth giving rise to crystals and bubbles elongate parallel to the freezing direction, c-axes were normal to crystal long axes. In a small pingo, bulk water existed temporarily at the freezing interface and freezing was unidirectional. In a larger pingo, variations in freezing rate were inferred. Later flow of ice modifies growth fabrics.

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Experimental Investigation of the Hydrate-Based Gas Separation of Synthetic Flue Gas with 5A Zeolite

Energies ◽

10.3390/en13174556 ◽

2020 ◽

Vol 13 (17) ◽

pp. 4556

Author(s):

Xiaoya Zang ◽

Na Zhang ◽

Xuebing Zhou ◽

Lihua Wan ◽

Deqing Liang

Keyword(s):

Water Content ◽

Gas Separation ◽

Flue Gas ◽

Gas Adsorption ◽

Physical Adsorption ◽

Hydrate Formation ◽

Co2 Separation ◽

Type B ◽

Influence Of Water ◽

5A Zeolite

Coal combustion flue gas contains CO2, a greenhouse gas and driver of climate change. Therefore, CO2 separation and removal is necessary. Fortunately, 5A zeolites are highly porous and can be used as a CO2 adsorbent. In addition, they act as nuclei for hydrate formation. In this work, a composite technology, based on the physical adsorption of CO2 by 5A zeolite and hydrate-based gas separation, was used to separate CO2/N2 gas mixtures. The influence of water content, temperature, pressure, and particle size on gas adsorption and CO2 separation was studied, revealing that the CO2 separation ability of zeolite particles sized 150–180 μm was better than that of those sized 380–830 μm at 271.2 K and 273.2 K. When the zeolite particles were 150–180 μm (type-B zeolite) with a water content of 35.3%, the gas consumption per mole of water (ngas/nH2O ) reached the maximum, 0.048, and the CO2 separation ratio reached 14.30%. The CO2 molar concentration in the remaining gas phase (xCO2gas) was lowest at 271.2 K in the type-B zeolite system with a water content of 47.62%. Raman analysis revealed that CO2 preferentially occupied the small hydrate cages and there was a competitive relationship between N2 and CO2.

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Crystal size distribution of benzoic acid at its crystallization from the bulk of vapour phase

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19792165 ◽

1979 ◽

Vol 44 (7) ◽

pp. 2165-2172 ◽

Cited By ~ 1

Author(s):

Jaroslav Vítovec ◽

Jiří Smolík ◽

Josef Kugler

Keyword(s):

Benzoic Acid ◽

Cooling Rate ◽

Size Distribution ◽

Crystal Size ◽

Vapour Phase ◽

Crystal Size Distribution ◽

Water Dispersion ◽

Small Crystals ◽

Permeable Walls

Crystal size and their distribution were measured in the crystallizer with gas-permeable walls, at crystallization of benzoic acid vapours from the bulk of vapour phase in the mixture with nitrogen in dependence on concentration (in range from 1.1 to 23 vol.%), temperature (401 to 473 K) and velocity of mixture (0.5 to 6.6 cm/s). At small cooling rate of the mixture the vapours of benzoic acid are condensing in the form of droplets which at continuing cooling solidify. At cooling of the mixture by water dispersion create the needle-shaped crystals. The effect of concentration, temperature and velocity is not profound obviously because by evaporation of water is the mixture rapidly cooled and supersaturated. This results in creation of a large amount of crystal nuclei and thus also of small crystals.

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RELATION OF pH TO DRIP FORMATION IN MEAT

Canadian Journal of Research ◽

10.1139/cjr38d-016 ◽

1938 ◽

Vol 16d (9) ◽

pp. 255-267 ◽

Cited By ~ 15

Author(s):

L. Sair ◽

W. H. Cook

Keyword(s):

Crystal Size ◽

Protein Denaturation ◽

Maximum Amount ◽

The Other ◽

Absorptive Power ◽

Small Crystals ◽

Constant Rate ◽

Quick Freezing ◽

Frozen Tissue ◽

Two Factors

The quantity of drip obtained from meat frozen at a constant rate is affected by the period between slaughter and freezing, and the pH of the tissue. These two factors appear to act independently, and only the latter was studied extensively. In precooled meats the maximum amount of drip was obtained at about pH 5.2, and as the pH increased the net drip decreased to zero at about pH 6.4. Pork, beef and mutton behave similarly both with respect to the form of the drip-pH relation and the quantity of drip exuded at a given acidity. Beef is normally more acid than the other meats tested, and this can account for its greater tendency to drip in commercial practice.Microscopic studies showed that large crystals were always produced by slow-freezing, regardless of the pH of the material. The absence of drip from slowly frozen tissue at pH 6.4 is therefore not due to crystal size, but must be attributed to the greater re-absorbing power of the proteins in this region. Protein denaturation does not affect the quantity of drip obtained when meat is slowly frozen or stored for periods up to three days in the freezing zone. The weak re-absorptive power of the proteins at pH 5.2 must be attributed to their isoelectric condition in this region, rather than to their denaturation. It is only in this isoelectric region that the production of small crystals by quick-freezing will reduce the quantity of drip.

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