2024 AIChE Annual Meeting

(43d) Novel Experimental Technique for Measuring Equilibrium Adsorption Isotherms Under Dynamic Conditions

Authors

Ebner, A. - Presenter, University of South Carolina
Sanders, R., University of South Carolina
Ritter, J. A., University of South Carolina
A novel (but not new) experimental technique was developed for measuring equilibrium adsorption isotherms under dynamic conditions. It is generally referred to as the quasi-equilibrium. However, although a very powerful and simple method, it is seldom used for measuring equilibrium adsorption isotherms in more recent literature. This perhaps is because most researchers use commercial, readily available apparatuses for this purpose.

Nevertheless, the quasi-equilibrium technique involves pressurizing a column containing the adsorbent of interest with the gas of interest in such a way that the column is always instantaneously in equilibrium at the desired temperature. This entails carrying out the pressurization step as slow as possible to minimize any heat effects and to ensure instantaneous equilibrium. Hence, the method is relatively simple and applicable to any gas that does not exhibit significant kinetic limitations.

The method is especially advantageous for corrosive or poisonous gases like NH3, HCl, SO2, NO2, NO, H2S, etc. It is also advantageous for measuring equilibrium adsorption isotherms at elevated temperatures and pressures. Commercially available systems are quite limited when it comes to dealing with these types of gases and conditions.

This technique requires five relatively inexpensive key components: 1) the adsorption column, a system to heat the adsorption column (jacket or band heaters) to determine isotherms at different temperatures or for regeneration, 3) a calibrated reference vessel to determine the accessible He volume so the excess amount adsorbed can be calculated, 4) a very accurately calibrated and very low flow rate mass flow controller for the pressurization step, and 5) a vacuum pump for adsorbent regeneration.

This presentation will present the latest results obtained from this new experimental technique for measuring equilibrium adsorption isotherms under dynamic conditions.