Design of membrane based gas-liquid absorption units: a fast, efficient, high throughput batch to continuous methodology
Résumé
Membrane contactors offer promising perspectives for intensified gas-liquid absorption processes. A rational design of a membrane based absorption process ideally requires membrane material / solvent compatibility to be evaluated, together to key thermodynamics (i.e. gas solubility) and kinetics data. More specifically, the impact of gas and liquid velocities, as well as solvent loading, on effective mass transfer performances are of major importance for design purposes [1]. Classical, time consuming phase equilibria methods and steady state membrane gas absorption tests with different inlet solvent loadings are most often separately performed in order to determine these different data sets. A fast, compact, easy to use method has been developed in order to quickly assess, through a single experiment, both thermodynamics and mass transfer data (i.e. impact of gas / liquid velocity and solvent loading), based on a batch to continuous approach. The set-up can easily be scaled down (e.g. for systems for which very small volume of solvents are available), extended to multicomponent systems (absorption of different solutes in a given solvent) and used for studies of the influence of temperature or solvent degradation kinetics.
These different aspects will be shown and discussed, based on a series of experiments performed with physical and chemical solvents for CO2 absorption from a gaseous mixture.