Multiscale analysis of gas absorption in liquids Wylock, Dehaeck, Mikaelian, Larcy, Talbot, Colinet, Haut Transfers, Interfaces and Processes (TIPs) Université Libre de Bruxelles

TIPs department  Main objective of the research : Development of methods for the analysis of multiphase systems, with the focus on transport phenomena  Scientific topics : Gas absorption in liquids, drying, evaporation, small scale fluid physics (thin liquid film, contact line dynamics, …)

Outline of this presentation Presentation of 3 new theoretical, numerical and experimental methods for the characterization of gas absorption in liquids Characterization of the CO 2 absorption in aqueous amine solutions, in the frame of the development of capture processes

Our experimental tool : interferometry CO 2 HEP aqueous solution CO 2 Absorption of CO 2 in HEP aqueous solution in a Hele-Shaw cell CO 2 Hele Shaw cell Various HEP initial concentration and Various inital amount of CO 2 absorbed

5 Gas Liquid Interface Laser Polarizer Spatial filter Lens Beam splitter Miror 2 Miror 1 Camera Hele Shaw cell

6 Laser Camera 6 CO 2 Time evolution of the refractive index variation field in the Hele-Shaw cell

Contours of the refractive index variation field in the cell (  n x 10 4 ) CO 2 HEP Solution CO 2

Refractive index variations can be related to loading variations Loading (  ): (local) total amount of carbon moles (whathever the molecule it belongs to) per unit volume of the solution 0  is identified by refractometry

Proposed model for the time evolution of the loading variation field in the Hele Shaw cell CO 2 transfer rate between the gas and the liquid  max : max loading variation at the interface k : interface saturation kinetic constant D : pseudo diffusion coefficient describing the ability of the amine to move towards the interface

Model parameters identification by comparison with experiments [HEP] 0 = 1000 mol/m 3 No initial loading

Outline of this presentation Presentation of 4 new theoretical, numerical and experimental methods for the characterization of gas absorption in liquids Characterization of the CO 2 absorption in aqueous amine solutions, in the frame of the development of capture processes Development of a new experimental set up for the analysis of the dynamics and the morphology of bubbles rising in liquids

The experimental set up d e =2.5mm 80 % water – 20 % glycerol No perspective effect ! Data obtained : Precise mesure of the bubble volume Field of view : 14 cm 150 Hz pixels 2

Ellipsoidal bubbles with helical motion : frequency of the motion f A period of the helical motion is achieved when the bubble rise a distance of approximately 10 times its diameter

Outline of this presentation Presentation of 4 new theoretical, numerical and experimental methods for the characterization of gas absorption in liquids Characterization of the CO 2 absorption in aqueous amine solutions, in the frame of the development of capture processes Development of a new experimental set up for the analysis of the dynamics and the morphology of bubbles rising in liquids Characterization of gas absorption into a spherical liquid droplet, in the frame of the development of flue gas cleaning processes

Transfer of a component A from a gas phase to a liquid droplet in free fall in this gas Finite element resolution of dimensionless transport equations with COMSOL Multiphysics 3.4, in a reference frame attached to the mass center of the droplet (Re < 250, low solubility) Post processing :

Results

Results : low Re Pure diffusion in a sphere : Re = 0,1

Results : high Re Re = 200 Instantaneous saturation of a toroidal vortex periphery Diffusion inside this vortex

Conclusion Presentation of 3 new methods for the characterization of gas absorption in liquids, at different scale Focus given on the understanding of transport phenomena and their coupling Based on analytical, numerical and experimental approaches

Many thanks for your attention!