Boreskov Institute of Catalysis of the Siberian Branch of Russian ...

OP-III-8MODELLING OF NON-DISPERSIVE SO 2 ABSORPTION PROCESSLuis P., Garea A., Irabien A.Department of Chemical Engineering and Inorganic Chemistry, University of Cantabria,Avda. Los Castros s/n 39005, SpainFax: +34 942 201591; E-mail: luisp@unican.esIntroductionNon-dispersive absorption based on membranes has demonstrated a number ofwidespread advantages: controlled interfacial area, independent control of gas and liquid flowrates and it avoids solvent losses due to drops dragging (Karoor and Sirkar, 1993; Gabelmanand Hwang, 1999). However, the resistance of the membrane to mass transfer leads to theneed for a equipment optimization (Qi and Cussler, 1985). Most studies emphasize that thebest operating mode is the non-wetted mode (Luis et al., 2007; Yan et al., 2007) wheremembrane pores are filled by gas leading to a high diffusion coefficient in comparison withthat if pores were filled by a liquid. N,N-dimethylaniline is a hydrophobic compoundcommonly used as absorbent due to its affinity with SO 2 (Basu and Dutta, 1987; Bhattacharyaet al., 1996). Thus, hydrophilic membranes should be used to achieve a non-wetted contact.MethodsA hollow fibre hydrophilic membrane module made of alumina is studied as gas-liquidcontactor. In designing hollow fibre membrane modules for soluble gas removal, the masstransfer process into a fibre can be mathematically described by three flow models: gas-phaselaminar model, gas-phase plug flow model and gas-phase mixing model. A numerical analysisbased on previous works (Luis et al., 2007) was carried out to describe the performance of thehollow fibre membrane contactor for the removal of sulfur dioxide considering diffusioncontrolledmass transfer and an instantaneous reaction between SO 2 and the liquid.Experimental validation was also carried out in order to confirm the applicability of themodels.Results and discussionAccording to the mathematical modelling, the non-wetted operating mode shows higherprocess efficiency due to higher values of the mass transfer coefficient. The laminar and plugflow models estimate the same values of efficiency in the evaluated range of parameters. Thisrange is in good agreement with the operation conditions of the experimental system used tovalidate the model. The behaviour of both models can be explained because the main105