(583e) Use of a Novel Volumetric Differential Pressure Apparatus for Adsorption Equilibrium Measurements | AIChE

(583e) Use of a Novel Volumetric Differential Pressure Apparatus for Adsorption Equilibrium Measurements


Mangano, E. - Presenter, University of Edinburgh
Brandani, S., University of Edinburgh
Wang, J., University of Edinburgh
In this work we present the design of a new volumetric differential pressure apparatus for the measurement of adsorption equilibrium and kinetics. Conventional volumetric systems are based on the measurement of the absolute pressure to calculate the amount adsorbed in a calibrated volume. On the other hand, differential volumetric systems rely on the measurement of the differential pressure between two symmetric branches (namely, sample and reference) as the gas expands from the dosing to the uptake volumes. The key advantage of the use of the differential pressure (as opposed to absolute) is that it ensures the same accuracy in the entire pressure range available. This is particularly beneficial when adsorption isotherms up to high pressure need to be measured.

The system is designed to measure high pressure adsorption isotherms up to 270 bar. It is equipped with a differential and an absolute pressure transducer as well as thermocouples to measure the temperature of the dosing and the uptake volumes, including the direct measurement of the sample temperature. The system is designed with a focus on minimising the volumes, allowing accurate equilibrium and kinetic measurements with less than 100 mg of sample. In addition, the apparatus is designed to be completely modular. This allows to easily modify the system to adapt the volumes (enlarging the volumes if necessary, for example) or to change the setup in different configurations.

We present the detailed design of the experimental apparatus as well as the methodology to accurately calibrate the volumes and carry out reliable adsorption equilibrium measurements.

To validate the system we have carried out experiments on reference adsorbents using different gases in a range of experimental conditions. We also highlight the advantages and disadvantages of using the system in two different configurations.