Investigation of immobilized liquid membranes for gas and vapor separations based on asymmetric inorganic supports and non-volatile liquids

In the work at hand, Immobilized Liquid Membranes - ILM - for gas and vapor separations composed of the ionic liquid [BMIM][Tf2N] in ceramic capillary asymmetric supports are investigated. As becomes clear from a detailed literature review covering publications of the last 16 years, the aforementioned material combination promises more stable ILM in contrast to commonly employed polymeric supports and low-volatile liquids. In opposition to commonly employed ex-situ, manual ILM preparation methods, a novel continuous in-situ ILM preparation method is developed. This method offers the possibility of using oxygen or water sensitive liquids as membrane phase and allows for easier preparation of ILM leading one step further to industrial application. As a means for the novel in-situ ILM preparation method, imbibition kinetics of the porous supports are investigated experimentally by means of three different methods. The experimental results are successfully modelled by means of an approach based on the so-called Washburn Equation for description of capillary imbibition kinetics. Two different support types (hydrophobic and hydrophilic with two different pore diameters of the active layer each) with two liquids (Ionic liquid [BMIM][Tf2N] and a silicone oil as a reference liquid with well documented material properties) are employed. The novel continuous in-situ preparation is investigated in comparison to a manual, i.e. ex-situ preparation method. This ex-situ method allows for preparation of ILM without any pretreatment of the employed ionic liquid and the support yielding a sufficiently stable ILM. However, there is no information on the real thickness of this ILM available and no controlled preparation possible. On the other hand, the in-situ preparation enables the controlled preparation and adjustment of ILM thickness. In this method, a remaining film on the lumen side of the membrane supports poses a limit on the minimum achievable ILM thickness. A model based on classical film theory is set up to account for the film removal during the last step of the preparation method. The proposed model allows for successful design of ILM with designated thickness. Finally, a mathematical model capable of describing the simultaneous vapor separation of a propane/propylene mixture and reaction of propylene to hexene by means of a catalytically active ILM is presented in this section. Sticking to the findings of Eichmann (Marcus Eichmann: Zweiphasige Dimmerisierung von Propen und 1-Buten mit ionischen Flüssigkeiten, Dissertation RWTH Aachen University, 1999), a pseudo first order reaction for the propylene dimerization reaction is assumed. For evaluation of the model, both in-situ and ex-situ prepared ILM are employed for permeation experiments for non-reactive vapor separation of a propane/propylene mixture. Two parametric studies of the non-catalytically active and the catalytically active ILM are presented investigating the influence of the experimental parameters on the selectivity, permeability and propylene/propane absorption ratio of the ILM.

Grantor dc:publisher

Publikationsserver der RWTH Aachen University

Year dc:date

2008

Author dc:creator

• Krull, Florian Felix

Contributors dc:contributor

• Melin, Thomas

• info:eu-repo/classification/ddc/620
• Flüssigmembran
• Präparation
• Gaspermeation
• Benetzung
• Ingenieurwissenschaften
• Kapillarbenetzung
• Benetzungskinetik
• Washburn-Gleichung
• immobilisierte Flüssigmembran
• anorganische Membran
• imbibition
• capillary wetting
• Immobilized Liquid Membrane
• Washburn equation
• inorganic membrane

Statement dc:rights

• info:eu-repo/semantics/openAccess

Language dc:language

eng

Identifier

https://publications.rwth-aachen.de/search?p=id:%22RWTH-CONV-113020%22

OAI record oai:identifier

https://publications.rwth-aachen.de/oai2d?verb=GetRecord&metadataPrefix=oai_dc&identifier=oai%3Apublications.rwth-aachen.de%3A50477