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Mass transport mechanisms and module design aspects in the recovery of dilute volatile organic compounds by hydrophobic pervaporation

Trifunovic, Olivera LU (2004)
Abstract (Swedish)
Popular Abstract in Swedish

Hydrofob pervaporation är en lovande teknik för återvinning och anrikning av aromer under milda betingelser men kommersiella tillämpningar av denna process är fortfarande outvecklade. Bättre kunskap om masstransportfenomen i kompositmembran avsedda för pervaporation behövs för utveckling av membran medan processimulering är ett viktigt verktyg för att optimera modulutformning. Målet med detta arbete var att studera såväl masstransport genom kompositmembran som moduldesign vid aromåtervinning med pervaporation.



I studierna av membranegenskaper delades membranmotståndet i två delar: motståndet i det aktiva skiktet och motståndet i stödskiktet. Pervaporationsexperiment utfördes... (More)
Popular Abstract in Swedish

Hydrofob pervaporation är en lovande teknik för återvinning och anrikning av aromer under milda betingelser men kommersiella tillämpningar av denna process är fortfarande outvecklade. Bättre kunskap om masstransportfenomen i kompositmembran avsedda för pervaporation behövs för utveckling av membran medan processimulering är ett viktigt verktyg för att optimera modulutformning. Målet med detta arbete var att studera såväl masstransport genom kompositmembran som moduldesign vid aromåtervinning med pervaporation.



I studierna av membranegenskaper delades membranmotståndet i två delar: motståndet i det aktiva skiktet och motståndet i stödskiktet. Pervaporationsexperiment utfördes med homologa serier av alkoholer och estrar för att utvärdera inverkan av ämnenas egenskaper, som molekylstorlek, flyktighet, kemiska egenskaper och polaritet, på kompositmembranets separeringsförmåga. Sorptionsexperiment utfördes på samma polymermaterial som det aktiva skiktet och medeldiffusionskoefficienter beräknades från flux erhållna vid pervaporationsförsök. Såväl löslighetsstudierna som diffusionsstudierna visade att det finns en tendens till klusterbildning för vatten och små polära molekyler vilket i sin tur orsakar minskning i diffusivitet för de polära ämnen som transporteras genom membranet. Beträffande stödskiktets inverkan bör en lämplig kompromiss göras mellan material och geometrisk karaktäristik för stödstrukturen och det aktiva skiktets tjocklek för att förbättra masstransportegenskaperna. Detta gäller speciellt för tryckkänsliga ämnen.



Moduldesignaspekter studerades genom processimulering med en modifierad version av ett befintligt program avsett för aromåtervinning med pervaporation. Inverkan av viktiga process- och moduldesignparametrar på prestanda för en modul studerades för fyra aromämnen, två alkoholer och två estrar. Resultaten från simuleringarna visade att modellering av modulprestanda är en viktig aspekt vid optimering av pervaporationsanläggningar. (Less)
Abstract
Hydrophobic pervaporation has gained a lot of attention as an alternative process for mild aroma recovery, but the real commercial applications of this process are still in their infancies. Better understanding of mass transport phenomena in composite pervaporation membranes is essential from the point of view of membrane manufacturing, while process simulation is an important tool for predicting pervaporation module performance. With this in mind, the aim of this thesis was to investigate both the composite membrane performance and the module design aspects for pervaporative aroma recovery.



When evaluating the composite membrane performance, the resistance of the membrane was divided into two parts, the active layer... (More)
Hydrophobic pervaporation has gained a lot of attention as an alternative process for mild aroma recovery, but the real commercial applications of this process are still in their infancies. Better understanding of mass transport phenomena in composite pervaporation membranes is essential from the point of view of membrane manufacturing, while process simulation is an important tool for predicting pervaporation module performance. With this in mind, the aim of this thesis was to investigate both the composite membrane performance and the module design aspects for pervaporative aroma recovery.



When evaluating the composite membrane performance, the resistance of the membrane was divided into two parts, the active layer resistance and the support layer resistance. Pervaporation experiments were performed on homologous series of alcohols and esters in order to evaluate the influence of component properties, such as molecular size, volatility, chemical nature and polarity on the performance of the composite membrane. Additionally, the sorption experiments on the active layer polymer material were performed and the average diffusivity coefficients were calculated from a steady-state pervaporation flux. Both solubility and diffusivity studies show that there is a tendency towards the clustering of water and small polar molecules, which in turn causes the decrease in diffusivity of the polar permeating species. Regarding the influence of the support layer, a suitable compromise between the nature and geometric characteristics of the support structure and the thickness of the active layer should be made in order to improve the mass transfer characteristics, especially for pressure-sensitive compounds.



Process simulation was performed using a modified version of an existing pervaporation simulation tool for aroma recovery, in order to investigate module design aspects of pervaporation. By applying the simulation to four aroma compounds, two alcohols and two esters, the influence of major process and module design parameters on the performance of a single module has been investigated. The results of the simulation show that detailed modelling of single module behaviour is an important aspect of the optimisation of pervaporation plant performance. (Less)
Please use this url to cite or link to this publication:
author
supervisor
opponent
  • Professor Voilley, Andree, Universite de Bourgogne, Dijon, France
organization
publishing date
type
Thesis
publication status
published
subject
keywords
Livsmedelsteknik, Food and drink technology, Teknik, Technological sciences, Aroma recovery, Module design, Hydrophobic pervaporation, Mass transport
pages
59 pages
publisher
Department of Food Technology, Lund University
defense location
Room K:B, Centre for Chemistry and Chemical Engineering, Getingevägen 60, Lund Institute of Technology
defense date
2005-06-17 10:15
ISBN
91-628-6480-7
language
English
LU publication?
yes
id
ef706cf0-4007-49df-9d97-a3cabe803f63 (old id 545046)
date added to LUP
2007-10-13 15:15:19
date last changed
2016-09-19 08:45:09
@misc{ef706cf0-4007-49df-9d97-a3cabe803f63,
  abstract     = {Hydrophobic pervaporation has gained a lot of attention as an alternative process for mild aroma recovery, but the real commercial applications of this process are still in their infancies. Better understanding of mass transport phenomena in composite pervaporation membranes is essential from the point of view of membrane manufacturing, while process simulation is an important tool for predicting pervaporation module performance. With this in mind, the aim of this thesis was to investigate both the composite membrane performance and the module design aspects for pervaporative aroma recovery.<br/><br>
<br/><br>
When evaluating the composite membrane performance, the resistance of the membrane was divided into two parts, the active layer resistance and the support layer resistance. Pervaporation experiments were performed on homologous series of alcohols and esters in order to evaluate the influence of component properties, such as molecular size, volatility, chemical nature and polarity on the performance of the composite membrane. Additionally, the sorption experiments on the active layer polymer material were performed and the average diffusivity coefficients were calculated from a steady-state pervaporation flux. Both solubility and diffusivity studies show that there is a tendency towards the clustering of water and small polar molecules, which in turn causes the decrease in diffusivity of the polar permeating species. Regarding the influence of the support layer, a suitable compromise between the nature and geometric characteristics of the support structure and the thickness of the active layer should be made in order to improve the mass transfer characteristics, especially for pressure-sensitive compounds.<br/><br>
<br/><br>
Process simulation was performed using a modified version of an existing pervaporation simulation tool for aroma recovery, in order to investigate module design aspects of pervaporation. By applying the simulation to four aroma compounds, two alcohols and two esters, the influence of major process and module design parameters on the performance of a single module has been investigated. The results of the simulation show that detailed modelling of single module behaviour is an important aspect of the optimisation of pervaporation plant performance.},
  author       = {Trifunovic, Olivera},
  isbn         = {91-628-6480-7},
  keyword      = {Livsmedelsteknik,Food and drink technology,Teknik,Technological sciences,Aroma recovery,Module design,Hydrophobic pervaporation,Mass transport},
  language     = {eng},
  pages        = {59},
  publisher    = {ARRAY(0x991e008)},
  title        = {Mass transport mechanisms and module design aspects in the recovery of dilute volatile organic compounds by hydrophobic pervaporation},
  year         = {2004},
}