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Ultrasound does not only promote desorption but alsoenhances the mass transfer of sorption processes. We discuss thearising problems and basic effects when applying ultrasound dur-ing sorption processes in order to show the potentials of this tech-nique.
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Influence of Water on the Selectivity ofNew Porous Solids for Air SeparationProcesses
M . S e e l b a c h
R . S t a u d t
J . U . K e l l e r
Institute of Fluid- and Thermodynamics, University of Siegen,Germany, [email protected]
Adsorption equilibria of the gases N2, O2 and H2O and some of theirbinary and ternary mixtures on a molecular sieve have been mea-sured in the pressure range 0 � p � 0.15 MPa at three constanttemperatures, T = 293 K, 313 K and 333 K. Pure gas adsorptionequilibria were measured gravimetrically [1]. Coadsorption dataof the binary mixtures N2/O2 and the ternary mixtures N2/O2/H2O will be obtained by using the volume-gravimetric-chromato-graphic method [2, 3]. Measurements presently are under way. Pre-liminary results will be reported on the poster exhibited at the Con-ference! Additionally, uptake-curves have been recorded duringthe adsorption process until equilibrium was reached. Thesecurves comprise important information of the kinetics of adsorp-tion process. Data of adsorption equilibria and uptake-curveswill be presented and discussed.
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Temperature Dependent SolventSystems ± An Alternative Method forRecycling Homogeneous Catalysts
C . F aÈ n g e w i s c h
A . B e h r
Chair of Process Development, Department of ChemicalEngineering, University of Dortmund, Germany
An industrial application of homogeneously catalyzed reactionscan only be realized if suitable concepts for recycling of the mostlyexpensive, homogeneously dissolved catalyst are developed. Spe-cial multicomponent solvent systems allow a single-phase reactionprocess by repression of the miscibility gap at reaction temperaturecombined with an easy product/catalyst separation by the two-phase technique at room temperature. Using such new systemsthe reaction process can be influenced actively and an easy recy-cling of the catalyst can be realized simultaneously.
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Oxygen Mass Transfer in a High SolidsLoading Three-phase Internal-LoopAirlift Reactor
C a r l a F r e i t a s
J o s e A . T e i x e i r a *
*Centro de Engenharia Biolo gica ± IBQF, Universidade do Minho,Campus de Gualtar, 4710-057 Braga, Portugal; Tel: +351253604400;Fax.: +351.253.678986; E-mail: [email protected]
The way volumetric mass transfer coefficient in a 60 L three-phaseinternal-loop airlift reactor with an enlarged degassing zone is in-fluenced by the airflowrate (riser superficial gas velocities between0.01 and 0.5 m/s), solids loading (up to 30% v/v), solids density (1023and 1048 kg/m3) and the liquid phase properties was studied. Theincrease of the airflow rate and the introduction of ethanol en-hanced the volumetric mass transfer coefficient in the system.The opposite effect was observed with the progressive introduc-tion of solids and a small increase on solids density. Correlationsfor the volumetric mass transfer coefficient with the riser superfi-cial gas velocity and solids loading were established, for the twosolids density and the two liquid-phases.
Figure.Schematic representation of the experimental airlift reactor(1 ± air feed; 2 ± regulation valve; 3 ± rotameter; 4 ± sieveplate; 5 ± oxygen electrodes).
737M u l t i p h a s e S y s t e m sChemie Ingenieur Technik (73) 6 I 2001
