The separation of meta- and para-xylene by pervaporation in the presence of CBr4, a selective feed-complexing agent

Wytcherley, Randi Wright; McCandless, F. P.

doi:10.1016/0376-7388(92)87040-5

Cited by 25 publications

(6 citation statements)

References 10 publications

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“…Initial attempts at using pervaporation through membranes focused on polymers containing side groups that interacted strongly with one of the xylene isomers. − However, the selectivities were too low (<2.8) to be of industrial use. A complexing agent improved the selectivity of some membranes but not by much . More recently, poly(vinyl alcohol) membranes containing cyclodextrin were studied by Miyata et al When the permeants were fed to the membrane as vapors generated directly from the liquid (no helium diluent), a 10% p -xylene in o -xylene mixture was separated with a selectivity of about 4.…”

Section: Introductionmentioning

confidence: 99%

Aromatic Permeation through Crystalline Molecular Sieve Membranes

Gump

Tuấn

Noble

et al. 2000

Ind. Eng. Chem. Res.

104

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The fluxes of aromatic molecules (p-xylene, o-xylene, and benzene) were measured as a function of temperature and feed partial pressure through several molecular sieve membranes (SAPO-5, SAPO-11, and mordenite) and three types of MFI membranes (silicalite-1, ZSM-5, and boron-substituted ZSM-5). Single-file diffusion appeared to control transport through the SAPO and mordenite membranes. Hence, those membranes showed ideal selectivities greater than 1 for benzene over the xylene isomers but no separation selectivities for the mixtures. Surface diffusion and activated gaseous transport were the controlling mechanisms for the MFI membranes. The highest p-xylene/o-xylene selectivities were obtained for a boron-substituted ZSM-5 membrane. At feed partial pressures of 2.1 kPa and at a temperature of 425 K, the best selectivities were 130 (ideal) and 60 (separation). Zeolite pores preferentially permeated p-xylene and took as long as 8 h to reach steady state. Nonzeolite pores preferentially permeated o-xylene after much shorter breakthrough times. Higher pressures of p-xylene distorted the membrane framework, resulting in increased o-xylene permeation and reduced selectivity. After reaching steady state, the flux of p-xylene through zeolite pores was stable for at least 10 h. The flux of o-xylene through nonzeolite pores was similarly stable at 373 K but continuously decreased for at least 12 h at 405 K.

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Section: Introductionmentioning

confidence: 99%

Aromatic Permeation through Crystalline Molecular Sieve Membranes

Gump

Tuấn

Noble

et al. 2000

Ind. Eng. Chem. Res.

104

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“…By applying the multicomponent Langmuir equation to Eqs. (20)- (22), the fluxes and selectivity in ternary mixtures can be calculated.…”

Section: Adsorption Of Xylenes In the CD Modified Membrane Can Be Assmentioning

confidence: 99%

Energy Saving Separations Technologies for the Petroleum Industry: An Industry-University-National Laboratory Research Partnership

Dorgan¹,

Stewart²,

Way³

2003

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This project works to develop technologies capable of replacing traditional energy-intensive distillations so that a 20% improvement in energy efficiency can be realized. Consistent with the DOE sponsored report, Technology Roadmap for the Petroleum Industry, the approach undertaken is to develop and implement entirely new technology to replace existing energy intensive practices. The project directly addresses the top priority issue of developing membranes for hydrocarbon separations. The project is organized to rapidly and effectively advance the state-of-the-art in membranes for hydrocarbon separations. The project team includes ChevronTexaco and BP, major industrial petroleum refiners, who will lead the effort by providing matching resources and real world management perspective. Academic expertise in separation sciences and polymer materials found in the Chemical Engineering and Petroleum Refining Department of the Colorado School of Mines is used to invent, develop, and test new membrane materials. Additional expertise and special facilities available at the Idaho National Engineering and Environmental Laboratory (INEEL) are also exploited in order to effectively meet the goals of the project. The proposed project is truly unique in terms of the strength of the team it brings to bear on the development and commercialization of the proposed technologies. Background: Petroleum refining is the nation's most energy intensive industry. Estimates for 1994 indicate that the Petroleum industry used 6.3 quads (quadrillion BTU) [1]. Of this, atmospheric and vacuum distillation accounted for 35-40 percent of the total. Crude oils vary in content based on the place of origin and must be refined and separated into useful components. Currently this is primarily done by distillation, a process in which the fluids must be heated until boiling. This is the primary reason for the high energy costs associated with the refining process.

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“…Yet there are various other applications, which have been investigated or are currently under development. Especially organic‐organic separations by organophilic membranes are actively investigated and have been used for solvent separations such as toluene‐heptane, methanol‐benzene, and methanol‐toluene , or the separation of isomers, such as o ‐xylene, m ‐xylene, p ‐xylene, and ethyl benzene and dichlorobenzene isomers . Besides the separation of aromatic‐alicyclic components, such as benzene‐paraffin, benzene‐olefin, or toluene‐paraffin for which despite promising results at lab‐scale an industrial scale application is still lacking , especially the separation of mixtures with significant differences in polarity is of interest.…”

Section: Introductionmentioning

confidence: 99%

A Systematic Approach towards Synthesis and Design of Pervaporation‐Assisted Separation Processes

Scharzec

Waltermann

Skiborowski

2017

Chemie Ingenieur Technik

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While membrane processes like pervaporation are considered as key technology towards more sustainable separation processes, they are rarely considered in conceptual design. In order to enable an identification of promising applications, the current article proposes a systematic approach that covers the synthesis of pervaporation-assisted process variants and promotes the use of optimization-based methods for process analysis. It seeks to minimize and guide necessary experiments and includes competitive reference processes as well as further means for process intensification in the evaluation.

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The separation of meta- and para-xylene by pervaporation in the presence of CBr4, a selective feed-complexing agent

Cited by 25 publications

References 10 publications

Aromatic Permeation through Crystalline Molecular Sieve Membranes

Aromatic Permeation through Crystalline Molecular Sieve Membranes

Energy Saving Separations Technologies for the Petroleum Industry: An Industry-University-National Laboratory Research Partnership

A Systematic Approach towards Synthesis and Design of Pervaporation‐Assisted Separation Processes

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