Uysal, B.Z
Özilgen, M.
Axial dispersion of liquid in Mobile-Bed Contacting (MBC) was investigated employing transient-response technique with impulse input of NaCI tracer. Experiments were performed in a 0.195 m ID column. Three different packing diameters (15, 19.5 and 32 mm) and three different static bed heights (0.1, 0.195 and 0.3 m) were used. Gas flow rate was varied between 3.02 and 4.05 kg/m2/s and liquid flow rate from 2.4 to 10.4 kg/m2/s. Transfer function analysis of data yielded that Peclet number was practically independent of liquid and gas flow rates and static bed height but depended on packing size only. A simple correlation for Peclet number was developed
Chemical Engineering Communications


DOGU, G; CABBAR, C; Doğu, Timur (Informa UK Limited, 1991-01-01)
The single-pellet moment techniques previously developed for the evaluation of effective diffusion coefficient and effective thermal conductivity of a porous solid are combined and a procedure is proposed for the simultaneous evaluation of these constants from a single set of pulse response experiments. It is shown that both temperature and concentration response curves can be measured from a single pulse of oxygen injected into hydrogen carrier gas flowing past a catalyst pellet. It is shown that the zerot...
Acidity characterization and adsorption characteristics of cobalt and lead doped SBA15 mesoporous materials
Güner, Özge; Üner, Deniz; Department of Chemical Engineering (2007)
In this study, the surface acidity of Co and/or Pb doped SBA15 mesoporous catalysts were investigated by both diffuse reflectance fourier transform (DRIFT) infrared spectroscopy and transmission mode fourier transform infrared spectroscopy. Pyridine was used to identify the Brønsted and Lewis acid sites of the surface, at room temperature. From the DRIFT spectrum typical stretching vibrations of isolated terminal silanol (Si-OH) groups were observed for all the catalysts. These silanol group bands dissappea...
Quantum chemical simulation of nitric oxide reduction by ammonia (scr reaction) on v2o5 / tio2 catalyst surface
Soyer, Sezen; Önal, Işıl; Department of Chemical Engineering (2005)
The reaction mechanism for the selective catalytic reduction (SCR) of nitric oxide by ammonia on (010) V2O5 surface represented by a V2O9H8 cluster was simulated by density functional theory (DFT) calculations. The computations indicated that SCR reaction consisted of three main parts. In the first part ammonia activation on Brønsted acidic V-OH site as NH4+ species by a nonactivated process takes place. The second part includes the interaction of NO with pre-adsorbed NH4 + species to eventually form nitros...
Kinetic analysis of DSC and thermogravimetric data on combustion of lignite
Kök, Mustafa Verşan (Springer Science and Business Media LLC, 1996-06-01)
Thermal analysis increasingly being used to obtain kinetic data relating to sample decomposition. This work involves a comparative study of several methods used to analyse DSC and TG/DTG data obtained on the oxidation of Beypazari lignite. A general computer program was developed and the methods are compared with regard to their accuracy and the ease of interpretation of the kinetics of thermal decomposition. For this study, the ratio method was regarded as the preferred method, because it permits the estim...
Vulcan-Supported Pt Electrocatalysts for PEMFCs Prepared using Supercritical Carbon Dioxide Deposition
Bayrakceken, Ayse; Smirnova, Alevtina; Kitkamthorn, Usanee; Aindow, Mark; Tuerker, Lemi; Eroğlu, İnci; ERKEY, CAN (Informa UK Limited, 2009-01-01)
In this study, supercritical carbon dioxide (scCO(2)) deposition was used to prepare vulcan-supported Pt (Pt/Vulcan) electrocatalysts for proton exchange membrane fuel cells (PEMFCs), and the effects of process variables on the properties of the electrocatalysts were investigated. The two different methods used to reduce the organometallic precursor were thermal reduction in nitrogen at atmospheric pressure and thermal reduction in scCO(2). In the former method, the maximum Pt loading achieved was 9%, and t...
Citation Formats
B. Z. Uysal and M. Özilgen, “AXIAL DISPERSION OF LIQUID IN MOBILE-BED CONTACTING,” Chemical Engineering Communications, pp. 157–166, 1989, Accessed: 00, 2020. [Online]. Available: