Adsorption 11: 853–858, 2005 c  2005 Springer Science + Business Media, Inc. Manufactured in The Netherlands. VOC Adsorption in Circulating Gas Fluidized Bed WENLI SONG ∗ Multi-Phase Reaction Lab., Institute of Process Engineering, CAS, 100080, Beijing, China; Laboratoire des Sciences du G´ enie Chimique, CNRS, ENSIC-INPL, BP451 54001, Nancy, France wlsong@home.ipe.ac.cn DANIEAL TONDEUR Laboratoire des Sciences du G´ enie Chimique, CNRS, ENSIC-INPL, BP451 54001, Nancy, France LINGAI LUO Laboratoire LOCIE, Universit´ e de Savoie, 73376 Le Bourget du Lac cedex, France JINGHAI LI Multi-Phase Reaction Lab., Institute of Process Engineering, CAS, 100080, Beijing, China Abstract. The purpose of the work is to show that CFB adsorption process is technically feasible to obtain an interesting pollution abatement, and to set the bases of a process design. Experimental results are presented, obtained with toluene being adsorbed from an air stream on polymeric adsorbent in a batch operation circulating fluidized bed. This results in a breakthrough behavior at the top of the riser, analogous to a fixed-bed experiment. The existence of breakthrough curves that are astonishingly sharp in spite of the strong mixing of the solid phase implies that efficient toluene abatement can be achieved. The breakthrough curves can be used to predict the behavior of the process in a continuous mode where the adsorbent would be partially regenerated, and which would lead to an less than total toluene abatement. The shape of the breakthrough curves clearly depends on the operating parameters, in particular the gas flow rate and the solids circulation rate. The EMMS model was adapted and implemented to describe the flow pattern of gas and solid. The model predicts the relative volume fractions of these phases, the volume fractions inside each, the superficial velocities of gas and solid in each phase, and the average cluster size. From this description, an estimation of the apparent gas/solid mass transfer coefficients may be done, and their dependence on operating conditions investigated. Keywords: adsorption, circulating fluidized bed, volatile organic compounds 1. Introduction Volatile Organic Compounds (VOC) are the most com- mon air pollutants emitted from chemical, petrochemi- cal and allied industries. Adsorption is one of the most effective methods of controlling VOC emission. Ad- sorption processes are usually carried out in fixed beds, ∗ To whom correspondence should be addressed. the main reasons being that a 1arge number of theo- retical plates is often required, and that adsorbents are subject to strong attrition. Under certain circumstances, these factors are not prohibitive, and fluidized bed may be an interesting alternative. The expected advantages are continuous processing, the ability to treat large flows under moderate pressure drop, the possibility to handle dusty gases or slurries, good fluid side mass and heat transfer between fluid and particles. Among