Separation and Purification of p-Xylene from the Mixture of m-Xylene and p-Xylene by Distillative Freezing

Shiau, Lie‐Ding; Wen, Chun-Ching; Lin, Bo-Shiue

doi:10.1021/ie049145v

Cited by 36 publications

(45 citation statements)

References 2 publications

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“…The other ways for separating close-boiling mixtures in the open literature make use of the melting point differences of the mixtures in either a distillation freezing design configuration or a hybrid distillation/melt crystallization process. 16 −19 In Chapter 7 of a book by Doherty and Malone 20 alternative energy-efficient distillation configurations for the separation of ternary A/B/C systems with no azeotrope were discussed. However, those design configurations cannot directly be applied in this study because a two-column sequence was required in the base case of ternary A/B/C systems.…”

Section: Introductionmentioning

confidence: 99%

Energy-Saving Designs for Separation of a Close-Boiling 1,2-Propanediol and Ethylene Glycol Mixture

Chen

Hung

Lee

et al. 2015

Ind. Eng. Chem. Res.

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Separation of 1,2-propanediol and ethylene glycol is an important task for coproduction of these two compounds via hydrogenolysis of glycerol for the purpose of utilizing this biodiesel byproduct. These two compounds exhibit close-boiling behavior which requires many stages of a regular column and also large energy consumption to meet stringent product purity specifications. In this paper, several alternative designs are investigated in order to save steam cost and also total annual cost of this separation task. Alternative designs considered include multieffect distillation, heterogeneous azeotropic distillation, and extractive distillation. Significant reductions of 38.3% in steam cost and 30.6% in total annual cost as compared to the regular column can be obtained by a design flowsheet via an extractive distillation system using triethylene glycol as entrainer. Methods for further improving the economics of this extractive distillation system have also been investigated. A simple worthwhile improved design is to preserve the energy from the hot entrainer to preheat the fresh feed via a feed-effluent heat exchanger. With this simple improvement, a further 12.8% reduction in steam cost can be made as compared to the original extractive distillation system.

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Section: Introductionmentioning

confidence: 99%

Energy-Saving Designs for Separation of a Close-Boiling 1,2-Propanediol and Ethylene Glycol Mixture

Chen

Hung

Lee

et al. 2015

Ind. Eng. Chem. Res.

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“…Nevertheless, the structural similarities and the close boiling point make separation and purification of xylene monomers very difficult, for instance, the classic distillation method is not applicable. The current separation of these isomers is based on the difference in adsorption characteristic and freezing point (referring to adsorption and fractional crystallization), dealing with 75% and 25% of xylene isomer separation, respectively . As for the adsorption method, various absorbents have been adopted such as zeolites, carbon materials, polymers, silicon gels, and metal–organic frameworks (MOFs) .…”

Section: Important Separation Systemmentioning

confidence: 99%

Membrane Separation in Organic Liquid: Technologies, Achievements, and Opportunities

et al. 2018

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Membrane technology is one of the most promising technologies for separation and purification that is routinely and commercially employed in aqueous solutions. In comparison, its applications in organic solvents are severely underdeveloped mainly due to the poor stability of traditional polymer membranes in organic solvents. The emerging materials such as crosslinked polymers, covalent organic frameworks, metal–organic frameworks, conjugated microporous polymers, carbon molecular sieves, and graphene provide the solutions to address this problem. The membranes constructed with these novel materials show outstanding separation performance in regard to both high selectivity and solvent permeability, greatly pushing forward utilization of membrane technology in organic media. Here, an overview of the most important organic mixtures that need to be separated, the major separation processes adopted nowadays in organic solvents, and the recent progress in new developed membranes is provided.

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“…A new separation technology, called stripping crystallization (SC) or distillative freezing (DF), has been recently developed in our laboratory to separate mixtures with close boiling temperatures, including mixed xylenes [4][5][6], diethylbenzene isomers [7], and a benzene/cyclohexane mixture [8]. In principle, SC is operated under a triple-point condition, in which the liquid mixture is simultaneously vaporized and crystallized due to the three-phase equilibrium.…”

Section: Introductionmentioning

confidence: 99%

Purification of C9 Arenes by Stripping Crystallization

2011

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A new separation technique called stripping crystallization (SC) is applied for purification of a mesitylene/pseudoumene mixture. SC combines distillation and crystallization to produce pure crystals due to the three-phase equilibrium. The experiments demonstrate that a batch SC operation can purify pseudoumene from 85 % to 95 % for the pseudoumene-rich mixture with a recovery rate of 51 % while it can only purify mesitylene from 85 % to 88 % for the mesitylenerich mixture with a recovery rate of 34 %. Compared to azeotropic distillation, SC is a clean separation technology as no chemicals are added. SC can be continued until the liquid phase is completely eliminated and only pure crystals remain in the feed. Compared to conventional crystallization, filtration or centrifugation is not needed to separate the solid crystals from the mother liquor since no mother liquor is present together with the crystals. In addition, crystal washing is not required since no impurities adhere to the crystal surfaces at the end of operation.

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Separation and Purification of p-Xylene from the Mixture of m-Xylene and p-Xylene by Distillative Freezing

Cited by 36 publications

References 2 publications

Energy-Saving Designs for Separation of a Close-Boiling 1,2-Propanediol and Ethylene Glycol Mixture

Energy-Saving Designs for Separation of a Close-Boiling 1,2-Propanediol and Ethylene Glycol Mixture

Membrane Separation in Organic Liquid: Technologies, Achievements, and Opportunities

Purification of C9 Arenes by Stripping Crystallization

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