Adsorptive separation of light olefins from paraffins

Ruthven, Douglas M.; Reyes, Sebastián C.

doi:10.1016/j.micromeso.2007.01.005

Cited by 181 publications

(155 citation statements)

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“…Potentials that are close to model B were used by Ruthven and Derrah (1972) as well as by Demontis and co-workers (Demontis et al 1997(Demontis et al , 2005(Demontis et al , 2006.…”

Section: Zeolite and Intermolecular Potentialmentioning

confidence: 99%

Influence of the Methane–Zeolite a Interaction Potential on the Concentration Dependence of Self-Diffusivity

Krishna

Yashonath

Schüring

et al. 2011

Adsorption Science & Technology

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Studies on the diffusion of methane in a zeolite structure type LTA (as per IZA nomenclature) have indicated that different types of methane-zeolite potentials exist in the literature in which methane is treated within the united-atom model. One set of potentials, referred to as model A, has a methane oxygen diameter of 3.14 Å, while another set of potential parameters, model B, employs a larger value of 3.46 Å. Fritzsche and co-workers (1993) have shown that these two potentials lead to two distinctly different energetic barriers for the passage of methane through the eight-ring window in the cation-free form of zeolite A. Here, we compute the variation of the self-diffusivity (D) with loading (c) for these two types of potentials and show that this slight variation in the diameter changes the concentration dependence qualitatively: thus, D decreases monotonically with c for model A, while D increases and goes through a maximum before finally decreasing for model B. This effect and the surprising congruence of the diffusion coefficients for both models at high loadings is examined in detail at the molecular level. Simulations for different temperatures reveal the Arrhenius behaviour of the self-diffusion coefficient. The apparent activation energy is found to vary with the loading. We conclude that beside the cage-to-cage jumps, which are essential for the migration of the guest molecules, at high concentrations migration within the cage and guest-guest interactions with other molecules become increasingly dominant influences on the diffusion coefficient and make the guest-zeolite interaction less important for both model A and model B.

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“…Potentials that are close to model B were used by Ruthven and Derrah (1972) as well as by Demontis and co-workers (Demontis et al 1997(Demontis et al , 2005(Demontis et al , 2006.…”

Section: Zeolite and Intermolecular Potentialmentioning

confidence: 99%

Influence of the Methane–Zeolite a Interaction Potential on the Concentration Dependence of Self-Diffusivity

Krishna

Yashonath

Schüring

et al. 2011

Adsorption Science & Technology

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“…Zeolites, as adsorbents, have been extensively used in the hydrocarbon separation in petroleum or petrochemical industries [2,[5][6][7][8][9][10]. Zeolite core-shell composites are novel class of materials for their potential application in the field of catalysis, adsorption, and storage and controlled release [11][12][13][14][15].…”

Section: Introductionmentioning

confidence: 99%

Fixed-Bed Adsorption Separation Of Xylene Isomers over SiO2/Silicallite-1 Core-Shell Adsorbents

Khan¹,

Rajendran²,

Lai³

2013

Chem. Eng. Res. Bull.

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Abstract:SiO 2 /Silicalite-1 core-shell material has been demonstrated as potential shape selective adsorbent in gas phase separation of p-xylene from a mixture of p/o-xylene isomers. The core-shell composite comprised of large silica core and thin polycrystalline silicalite-1 shell which was synthesized via a self-assembly of silicalite-1 nanocrystals on core silica surface followed by a secondary seeded growth method. The core materials, SiO 2 used in this study has mesoporosity with an average pore diameter of 60Å and hence offers no shape selectivity for xylene isomers. However, the shell, silicalite-1 contains rigid pore structures and preferentially adsorbs p-xylene from their isomers mixtures. A series of adsorption fixed bed breakthrough adsorption/desorption experiment was performed to obtain the equilibrium isotherms and adsorption isotherm parameters of xylene isomers. The equilibrium isotherms of xylene isomers follow the Langmuir's model. A chromatographic adsorption model has been used to describe the fixed-bed breakthrough profiles of xylene isomers. The model has successfully predicted the responses of the binary mixtures of p/o-xylene isomers. The SiO 2 /silicalite-1 core-shell adsorbents have shown para-selectivity as high as 15.

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confidence: 99%

“…Previous literatures have confirmed that pure siliceous 8-membered ring (MR) zeolites, e.g., CHA or deca-dodecasil 3R (DD3R) have shown superior performance on the separation of propylene and propane [1]. But the suitable zeolites for separation of ethylene and ethane are still a great challenge.…”

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confidence: 99%

Surprising separation selectivity of ethylene from ethane over pure siliceous zeolites with framework flexibility

Meng

Xiao

2018

Sci. China Mater.

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Recovery and purify of light olefins from the off-gas of the catalytic crackers have been focused for more than 50 years, driven largely by the escalating demand for feedstock for production of polyethylene and polypropylene, which requires the separation of C 2 H 4 /C 2 H 6 and C 3 H 6 /C 3 H 8 mixtures in which the olefins and paraffins are present at roughly equal concentrations [1,2]. Distillation operated at low temperatures (cryogenic distillation) or high pressure is one of the most useful methods for the separation and purify of these light olefins. However, these processes are energetically inefficient and therefore costly since the differences in volatility between the olefins and corresponding paraffins are so small, which require the separation column operated at high reflux, with more than 100 plates [2]. As a consequence, more than 0.3% of the global energy was consumed in the separation of ethylene and propylene from the corresponding paraffins. For the sake of energy-saving and cost-reducing, developing the efficient adsorption systems has been regarded as one of alternative technologies. However, no economically viable adsorptive separation process has yet emerged up to now, due to the relatively strong interaction between the olefins and selective adsorbents, which results in the complex regeneration process. As a result, new kinetically selective adsorbents for light olefins separation have been paid much attention in recent years.Porous materials are promising candidates for efficient separation of gas mixtures by distinguishing the differences in molecular sizes, shapes, and polarities. Recently, custom-designed porous materials, in termed of metalorganic frameworks (MOFs) and/or porous coordination polymers (PCPs) with open lattices formed from inorganic centers (nodes) and organic linking groups have been paid much attention due to their inherent diversity, which afford precise control over pore chemistry and pore size and consequently excellent performance in gas separation or capture such as ethylene [3] and 1,3-butadiene [4]. However, the low thermal stability still limits their wide applications in the separation of light olefins from corresponding paraffins since thermal treatments are always required for regeneration of the adsorbents once the pores are blocked.Zeolites, especially pure siliceous zeolites with suitable microporous structure would be ideal adsorbents for the separation of light olefins with paraffins because of their high thermal stability for regeneration and neutral framework for olefins non-oligomerization. Previous literatures have confirmed that pure siliceous 8-membered ring (MR) zeolites, e.g., CHA or deca-dodecasil 3R (DD3R) have shown superior performance on the separation of propylene and propane [1]. But the suitable zeolites for separation of ethylene and ethane are still a great challenge.Excitingly, a joint team lead by Corma, Corcoran, Rey, and Ravikovitch [5] recently reported new pure siliceous zeolite (ITQ-55), which could kinetically separate ethy...

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Adsorptive separation of light olefins from paraffins

Cited by 181 publications

References 20 publications

Influence of the Methane–Zeolite a Interaction Potential on the Concentration Dependence of Self-Diffusivity

Influence of the Methane–Zeolite a Interaction Potential on the Concentration Dependence of Self-Diffusivity

Fixed-Bed Adsorption Separation Of Xylene Isomers over SiO2/Silicallite-1 Core-Shell Adsorbents

Surprising separation selectivity of ethylene from ethane over pure siliceous zeolites with framework flexibility

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