Characterisation of an analogue liquid for hydrodynamic studies of gas-ionic liquid flows

Azzopardi, Barry J.; Agunlejika, Ezekiel O.; Zhao, Donglin; Kaji, Ryuhei; Hewakandamby, Buddhika N.

Abstract

Ionic liquids are liquid salts at low temperatures (normally less than 100°C). They are powerful solvents with very low vapour pressure. They have great potentials in many applications such as gas absorption and chemical synthesis. However, they are expensive. This limits extensive studies towards establishing phenomenological models. To address this limitation, an analogue liquid, with properties similar to an ionic liquid, has been identified which on the grounds of cost and safety appears to be suitable.

In this paper, the hydrodynamic behaviour of an ionic liquid in a bubble column is compared with those of water and other liquids with similar physical properties. Average gas holdup, bubble coalescence, bubble size and specific interfacial area with different liquids are examined. Gas hold-up was determined by monitoring the change of conductivity between two flush mounted rings. The differences in bubble size and coalescence are revealed by analysing the stills taken from a high speed video camera. The dominant flow pattern in a small diameter column with ionic liquids or other fluids having similar viscosity is slug flow. The small bubbles in the liquid slugs make a smaller contribution to the specific interfacial area than Taylor bubbles. It is observed that Taylor bubbles can coalesce. The hydrodynamics of an ionic liquid in a bubble column can be estimated from that of a fluid with similar physical properties.

Citation

Azzopardi, B. J., Agunlejika, E. O., Zhao, D., Kaji, R., & Hewakandamby, B. N. (2017). Characterisation of an analogue liquid for hydrodynamic studies of gas-ionic liquid flows. Chemical Engineering Journal, 330, https://doi.org/10.1016/j.cej.2017.07.090

• Journal Article Type: Article
• Acceptance Date: Jul 14, 2017
• Online Publication Date: Jul 19, 2017
• Publication Date: Dec 15, 2017
• Deposit Date: Jul 24, 2017
• Publicly Available Date: Jul 24, 2017
• Journal: Chemical Engineering Journal
• Print ISSN: 1385-8947
• Electronic ISSN: 1385-8947
• Publisher: Elsevier
• Peer Reviewed: Peer Reviewed
• Volume: 330
• DOI: https://doi.org/10.1016/j.cej.2017.07.090
• Keywords: Bubble columns; Ionic liquids; Viscous liquids; Gas holdup; Bubble size; Flow regimes
• Public URL: https://nottingham-repository.worktribe.com/output/900131
• Publisher URL: http://www.sciencedirect.com/science/article/pii/S1385894717312378