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Application of Polymeric Hollow-Fiber Membranes in Air Filtration
Bulejko, Pavel ; Dohnal, Mirko (oponent) ; Friess, Karel (oponent) ; Svěrák, Tomáš (vedoucí práce)
Hollow-fiber membranes (HFMs) have widely been applied to many liquid treatment applications such as wastewater treatment, membrane contactors/bioreactors, membrane distillation etc. Despite the fact that HFMs are widely used for gas separation from gas mixtures, their use for mechanical filtration of aerosols is very scarce. This work studied filtration performance of polypropylene HFMs including filtration efficiency, pressure drop and pressure drop evolution with long-term dust loading. Filtration efficiency was measured using different challenging aerosols including micronized titanium dioxide powder and aerosolized ammonium sulfate. Pressure drop was measured in various configurations, including different HFM area and fiber diameter. Pressure drop evolution with long-term particle loading was carried out using a challenge dust as defined in ANSI/ASHRAE 52.2 standard. Mathematical models developed for prediction of air filtration efficiency and membrane permeability/pressure drop were compared applying them on the structural parameters of the HFMs. These membranes are characteristic of pore diameters of about 90 nm and relatively low porosity, thus high potential for nanoparticle removal from air. Furthermore, analysis on cake pressure drop and evaluation of energy demands for fun operation were done and compared with theoretically predicted values. Finally, an attempt to estimate life-cycle cost of air filtration using HFMs was outlined.
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Application of Polymeric Hollow-Fiber Membranes in Air Filtration
Bulejko, Pavel ; Dohnal, Mirko (oponent) ; Friess, Karel (oponent) ; Svěrák, Tomáš (vedoucí práce)
Hollow-fiber membranes (HFMs) have widely been applied to many liquid treatment applications such as wastewater treatment, membrane contactors/bioreactors, membrane distillation etc. Despite the fact that HFMs are widely used for gas separation from gas mixtures, their use for mechanical filtration of aerosols is very scarce. This work studied filtration performance of polypropylene HFMs including filtration efficiency, pressure drop and pressure drop evolution with long-term dust loading. Filtration efficiency was measured using different challenging aerosols including micronized titanium dioxide powder and aerosolized ammonium sulfate. Pressure drop was measured in various configurations, including different HFM area and fiber diameter. Pressure drop evolution with long-term particle loading was carried out using a challenge dust as defined in ANSI/ASHRAE 52.2 standard. Mathematical models developed for prediction of air filtration efficiency and membrane permeability/pressure drop were compared applying them on the structural parameters of the HFMs. These membranes are characteristic of pore diameters of about 90 nm and relatively low porosity, thus high potential for nanoparticle removal from air. Furthermore, analysis on cake pressure drop and evaluation of energy demands for fun operation were done and compared with theoretically predicted values. Finally, an attempt to estimate life-cycle cost of air filtration using HFMs was outlined.
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Gas and Vapour Transport and Mechanical Properties of Carbon Nanotube and Carbon Fibre-Reinforcement of Ethylene-Octene Copolymer Membranes
Sedláková, Zuzana ; Clarizia, G. ; Bernardo, P. ; Jansen, J.C. ; Slobodian, P. ; Svoboda, P. ; Kárászová, Magda ; Friess, K. ; Izák, Pavel
Helium, hydrogen, nitrogen, oxygen, methane and carbon dioxide were used for gas permeation rate measurements. Theoretical Maxwell’s model was used to predict and interpret gas transport properties in MMMs. Vapour transport properties were studied for aliphatic hydrocarbon (hexane), aromatic compound (toluene), alcohol (ethanol), as well as water. Organic vapours result more permeable than permanent gases in EOC-based membranes, with toluene and hexane permeabilities being about two orders of magnitude higher than permanent gas permeability. Carbon-filled membranes show that the EOC is an organophilic material that offers perspectives for application in gas/vapour separation with improved mechanical resistance.
Plný tet: SKMBT_C22014090110400 -  PDF
Plný text: content.csg - PDF
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Organic Vapour Sorption and Permeation in Polymer Gel Membrane Containing Imidazolium Based Ionic Liquid
Morávková, Lenka ; Vopička, O. ; Vejražka, Jiří ; Vychodilová, Hana ; Sedláková, Zuzana ; Friess, K. ; Izák, Pavel
In this work, vapour sorption and transport properties were studied for the aliphatic hydrocarbon (hexane), branched hydrocarbon (isooctane), and alcohol (ethanol) using a gravimetric sorption apparatus and a home-made laboratory-scale apparatus, respectively. The ionic liquid polymer gel membrane based on poly(vinylidene fluoride-cohexafluoropropylene) (abbreviated p(VDF-HFP)) was prepared by solvent casting from a solution in acetone. The used membrane contains 80 wt. % of the imidazolium basedionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([emim][Tf2N]).
Plný tet: SKMBT_C22014090110397 - PDF
Plný text: content.csg - PDF
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Thin Film Composite Membrane for Effective Raw Biogas Upgrading to Pipeline Quality Methane
Kárászová, Magda ; Vejražka, Jiří ; Veselý, Václav ; Friess, K. ; Randová, A. ; Jansen, J. C. ; Izák, Pavel
In this contribution we propose a method to upgrade biogas to the same quality of fuel standard natural gas. The latter contains more than 95 vol. % of methane. Using traditional membranes, such concentration of methane in the retentate could only be achieved using a multistep process. A recently proposed method for raw biogas purification from impurities and carbon dioxide by condensing water on swollen thin film composite membranes was found to be highly effective. The hydrophilic reverse osmosis membrane promotes the formation of a very thin selective water layer under condensing conditions below the dew point of the raw biogas feed. The large difference in permeability of the impurities in raw biogas (carbon dioxide, hydrogen sulfide) and methane through the water layer enables upgrading of raw biogas to biomethane quality in a single stage. Contrary to the classical purification processes, the proposed method does not require any biogas pretreatment, which makes this approach economically attractive. It represents an innovative approach to production of biomethane from biogas.
Plný tet: SKMBT_C22012102413470 - PDF
Plný text: content.csg - PDF
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Sorption Characteristics of PDMS in Ternary Systems Benzene (1) + Alcohols (2) + Ionic Liquid (3) and Corresponding Binary Subsystems
Randová, A. ; Bartovská, L. ; Hovorka, Š. ; Friess, K. ; Izák, Pavel
In this work the study of sorption characteristics of PDMS in ternary system benzene (1) + methanol or butanol (2) + ionic liquid (3) and corresponding binary subsystems at the temperature of 20°C is presented. The experimental data on total sorption were determined gravimetrically [3], the experimental data on preferential sorption were evaluated from the concentration change induced by an immersion of the membrane into the liquid mixture [3]. The volume changes of swollen membrane immersed in the studied liquid systems were determined from the dimensional changes of the membrane samples changes in X and Y axis dimensions were monitored directly in liquid by an optical method [1, 3] and membrane sheet thickness was measured by an Inductive Dial Indicator (Mahr, Germany).
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