Saturation loadings on 13X (faujasite) zeolite above and below the critical conditions. Part II: unsaturated and cyclic
- PDF / 1,129,691 Bytes
- 12 Pages / 595.276 x 790.866 pts Page_size
- 33 Downloads / 148 Views
Saturation loadings on 13X (faujasite) zeolite above and below the critical conditions. Part II: unsaturated and cyclic hydrocarbons data evaluation and modeling Alaa Al Mousa1 • Dana Abouelnasr2,3 • Kevin F. Loughlin2
Received: 9 June 2014 / Revised: 3 April 2015 / Accepted: 9 April 2015 / Published online: 22 April 2015 Ó Springer Science+Business Media New York 2015
Abstract The saturation loadings for subcritical adsorption of alkenes, aromatics and cyclic alkanes 13X zeolite are modeled using the modified Rackett model of Spencer and Danner (J Chem Eng Data 17(2):236–240, 1972) for the saturated liquid densities combined with crystallographic data for the 13X zeolite. Adsorption data from the literature is first critically evaluated and then compared to the model. Log–log plots are used to determine whether each isotherm is near saturation; isotherms that exhibit a (q ln q)/(q ln p) slope of zero at their maximum pressure point are assumed to be saturated. For subcritical isotherms, the reduced pressure at which all isotherms became saturated is found to be relatively constant below a molecular weight of 60 g/mol, and then to decrease exponentially with molecular weight above 60 g/mol. The highest loading is used from each isotherm that approaches saturation. Unsaturated isotherms are not considered further. The theoretical equation satisfactorily models the available experimental
Kevin F. Loughlin—American University of Sharjah (retired).
Electronic supplementary material The online version of this article (doi:10.1007/s10450-015-9671-y) contains supplementary material, which is available to authorized users. & Dana Abouelnasr [email protected] Kevin F. Loughlin [email protected] 1
Petrofac International Ltd, Sharjah, UAE
2
Department of Chemical Engineering, American University of Sharjah, P.O. Box 26666, Sharjah, UAE
3
California State University at Bakersfield, Bakersfield, USA
data for the alkenes and cyclic alkanes. However, steric factors are required in the model for the aromatics. For supercritical temperatures, no model presently exists to explain the data. However, the supercritical alkene data are satisfactorily modeled with an equation of the form qmax = 10 ± 2.0 g/100 g. There are no supercritical data for aromatic species or for cyclic alkanes. Keywords Unsaturated hydrocarbons Cyclic hydrocarbons 13X zeolite Sorbate densities Saturation loadings Sorbate molar volumes Critical conditions List of MW Pc Pr q qmax qmax,c
R Tc Tr ZRA
symbols Molecular weight (g/mol) Critical pressure (kPa) Reduced pressure Zeolite loading, g/100 g zeolite crystal Maximum zeolite loading, g/100 g zeolite crystal Theoretical maximum zeolite loading at the critical temperature, defined by Eq. 3, g/100 g zeolite crystal Gas constant, 8314 kPa-cm3/gmol K Critical temperature (K) Reduced temperature Rackett parameter
Greek letters C Normalized loading, dimensionless, calculated in Eqs. 6 and 7 eZ Crystallographic 13X zeolite void fraction, 0.428 (Breck 1974, p. 133) k Steric factor, the fract
Data Loading...
