UNCORRECTED PROOF Please cite this article in press as: R. Cherba´ nski, E. Molga, Intensification of desorption processes by use of microwaves—An overview of possible applications and industrial perspectives, Chem. Eng. Process. (2008), doi:10.1016/j.cep.2008.01.004 ARTICLE IN PRESS +Model CEP 5524 1–11 Available online at www.sciencedirect.com Chemical Engineering and Processing xxx (2008) xxx–xxx Intensification of desorption processes by use of microwaves—An overview of possible applications and industrial perspectives 1 2 R. Cherba ´ nski, E. Molga ∗ 3 Warsaw University of Technology, Chemical and Process Engineering Department, ul. Warynskiego 1, 00-645 Warszawa, Poland 4 Received 6 July 2007; received in revised form 5 December 2007; accepted 7 January 2008 5 Abstract 6 This review presents the state of the art regarding the possible intensification of desorption processes by use of microwave irradiation. The most important experimental and modeling results reported in the literature on the laboratory scale as well as on the industrial scale were collected in this paper. It follows from the review that microwave heating is a powerful novel method proving many advantages when utilized for regeneration of loaded adsorbents. In general, a short penetration depth could be a drawback of this very efficient heating method. Hence, it seems that the fluidized bed adsorbers are better choice than the fixed-bed ones when the microwave-assisted desorption step is carried out because more homogenous temperature distribution would be guaranteed. 7 8 9 10 11 12 © 2008 Published by Elsevier B.V. 13 Keywords: Adsorption; Microwave desorption; Regeneration of adsorbents; VOC; Review 14 15 1. Introduction—adsorption and desorption processes 16 Adsorption is a very important separation process, frequently 17 met in industrial and laboratory practice. It is widely used to 18 control the emissions of organic vapors such as hazardous air 19 pollutants (HAPs) and volatile organic compounds (VOCs), 20 plays a significant role in processes of soil remediation from 21 VOCs and in many others applications. Extensive overview of 22 industrial applications of adsorption processes can be found in 23 numerous books and publications—e.g. see [1–4]. 24 Recently adsorption is also used in adsorptive reactors, where 25 it is integrated with chemical reactions carried out simulta- 26 neously in the same single apparatus [5–13]. This integrated 27 approach may leads to a significant reduction of investment costs 28 as well as of energy expenditures and waste production. Then 29 also a reasonable improvement of the reactor productivity can 30 be achieved due to increased selectivity and yield towards the 31 demanded product. 32 All mentioned above applications are the cyclic processes— 33 i.e. after a saturation of the adsorbent with adsorbed species a 34 regeneration step (desorption) should be executed. So, the des- 35 ∗ Corresponding author. E-mail address: molga@ichip.pw.edu.pl (E. Molga). orption process, which is necessary to regenerate the adsorbent 36 and recovery the adsorbed compounds, may be sometimes a 37 crucial step controlling an efficiency of the entire process under 38 consideration. 39 There are three main methods used to regenerate the adsor- 40 bents: 41 • pressure swing regeneration (PSR), 42 • temperature swing regeneration (TSR), 43 • reactive regeneration (RR). 44 PSR of the adsorbent, applied in a simple separation technol- 45 ogy as well as in integrated processes carried out in adsorptive 46 reactors, is very well established, developed and described in the 47 literature [1,2,4,14–21]. However, PSR approach is a fully effec- 48 tive method only for processes carried out at elevated pressures. 49 Otherwise the installation should be additionally equipped with 50 compressors or/and vacuum pumps, which complicates the pro- 51 cess and deteriorates its efficiency. Application of PSR process 52 is also restricted to fixed-bed adsorbers and reactors. 53 TSR of the adsorbent, being an alternative method to the 54 PSR one, is particularly convenient for adsorption carried out 55 at low temperature, when the desorption process is executed at 56 higher temperature. TSR method is usually less effective and 57 0255-2701/$ – see front matter © 2008 Published by Elsevier B.V. doi:10.1016/j.cep.2008.01.004