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Performance of Continuous Micro Photo Reactor – Comparison with Batch Process
Drhová, Magdalena ; Hejda, S. ; Křišťál, Jiří ; Klusoň, Petr
Utilization of the flow chemistry as well as microreactors belongs to the latest trends in chemical engineering. Continuous microreactors of various kinds can be found in the literature, for example the micromixers, micro packed beds, or micro photo reactors. In order to evaluate the benefits of microtechnology application for the given process, the performance of a particular microreactor needs to be compared with the conventional setup. This contribution presents the performance of a continuous micro photo reactor in comparison with a batch process. Two model reactions were selected: the catalyzed photooxidation of 4-chlorophenol (4-CP) and the singlet oxygen chemical quencher 9,10-dimethylanthracene (DMA) in dimethylformamide. The tests were carried out using advanced opto-chemical apparatus with a well-defined light filter corresponding to the absorption bands of the used photo catalysts.
Plný tet: SKMBT_C22012102414080 -  PDF
Plný text: content.csg - PDF
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Hydrodynamic and Heat Transfer Model of a Gas-Liquid Microreactor
Křišťál, Jiří ; Stavárek, Petr ; Staněk, Vladimír ; Jiřičný, Vladimír ; Simoncelli, A. ; Vanhoutte, D. ; Tarchini, R. ; Talford, M. ; Hass-Santo, K. ; Benzinger, W.
In this contribution we present a hydrodynamic and heat transfer model of a microreactor for a gas-liquid reaction. In the course of formulation of the model, we considered the characteristic features of the studied system – the gas-liquid flow pattern and the change in physical properties induced by pressure and temperature variation along the microreactor. Based on the input information (gas and liquid flow rates, compositions, temperatures), the model calculates the two-phase pressure drop and outlet temperature as the principal result. These results serve as a basis for the design of an intensified pilot scale microreactor.
Plný tet: SKMBT_C22012102413550 - 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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Process-Based Model of Mixed-Matrix Membrane
Čapek, P. ; Hejtmánek, Vladimír ; Veselý, M. ; Sysel, P. ; Kočiřík, Milan ; Brabec, Libor ; Zikánová, Arlette ; Bernauer, B. ; Fíla, V.
The focus of this contribution was on the formulation and verification of a process-based model of the mixed-matrix membrane that consisted of the polyimide matrix synthesized from the monomers 4,4’-(hexafluoroisopropylidene)diphtalic anhydride and 4,4’-oxydianiline, and silicalite-1. When a solution of a polyimide precursor in N,N-dimethylformamide was ready, silicalite-1 particles were dispersed in the solution and the dispersion was subsequently cast on a Teflon support plate. An initial mass ratio of silicalite-1 and polyimide was about 1:1. After solvent removal, the films were heated in subsequent steps up to 230°C for two hour. From a process-based model point of view, a key operation of the entire synthesis was slow sedimentation of silicalite particles in the viscous solution. Preliminary observation of 2D cuts through the solid membrane in a scanning electron microscope revealed that there were a lot of contacts among the silicalite particles. Therefore, a sequential (ballistic) deposition algorithm, well representing sedimentation in a low-energy environment, was used to create an off-lattice model of spatial distribution of the silicalite particles in the polyimide matrix.
Plný tet: SKMBT_C22012102413461 - PDF
Plný text: content.csg - PDF
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Changes in Ion Exchanger Catalysts after More than 10 Year Time-on-Stream
Jeřábek, Karel ; Hanková, Libuše ; Holub, Ladislav ; Slavík, H.
In this contribution will be reported results of examination of a series of industrial ion exchanger catalysts samples exposed to the environment of catalytic reactor in process of esterification of acrylic acid with methanol for more than 10 years. There was evaluated their acid capacity, swelling and using inverse steric exclusion chromatography (ISEC) also their morphology in water-swollen state. For comparison, similarly were evaluated also reference samples of the same but virgin ion exchangers.
Plný tet: SKMBT_C22012102413430 - PDF
Plný text: content.csg - PDF
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Theoretical Background for Predicting the Properties of Petroleum Fluids via Group Contribution Methods
Bogdanić, Grozdana ; Pavlíček, Jan ; Wichterle, Ivan
The major problem encountered in the petroleum industry lies in the proper thermodynamic representation of rather complex fluids. In this work, the UNIFAC group contribution method for predicting the properties of such fluids has been exploited as a basis for their description in terms of model compounds. Standard thermodynamic procedures are used to estimate the critical properties, acentric factors, and molecular weights for the model compounds. In such a way, the already available generalized methods can be used for calculations of the phase equilibrium in complex petroleum mixtures.
Plný tet: SKMBT_C22012102413400 - PDF
Plný text: content.csg - PDF
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