Ind. Eng. Chem. Process Des. Dev. 1983, 22, 172-174
172
Methane AdsorptiQn
on 5A IHlolecuCar S h e in the Pressure Range 4 to 690 kPa
An adsorption apparatus consisting of an electrobalance housed in a stainless steel container was designed and constructed so that gas adsorption data could be taken at pressures above and below atmospheric conditions. The apparatus was tested by obtaining experimental adsorption isotherms for methane on 5A molecular sieve at 273,298,and 308 K over pressures ranglng from 4 to 690 kPa. The resutts are compared with the low-pressure data of Loughiin and of Lederman and Williams and the high-pressure data of Rolniak. A slightly modified form of Ruthven's statistical model was used to fit the experimental data with less than 4 % error.
Introduction The classification of adsorption methods is generally divided into two groups, dynamic and static. Dynamic measurements are exeinplified by chromatographic determinations of isotherms, whereas static measurements are normally made by volumetric or gravimetric techniques. With the latter method, more accurate experimental data can be obtained due to the capability of measuring small mass changes at constant pressure. Most gravimetric measurements are conducted below atmospheric pressure b e c a w the housing for the experimental apparatus is typically made of glass. The purpose of this paper is to present data for the adsorption of methane on 5A molecular sieve at pressures both above and below atmospheric conditions using an electrobalance housed in a container suitable for high-vacuum and high-pressure work. The adsorption of methane on 5A zeolite, which has been studied previously by other investigators, was chosen for this work so that the results could be compared over the complete pressure range. For example, Kidnay and Hiza (1963) performed volumetric studies at low pressures (
