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Small bubbles formation and contribution to the overall gas holdup in large diameter columns of very high viscosity oil

Mohammed, Shara K.; Hasan, Abbas H.; Dimitrakis, Georgios; Azzopardi, Barry J.

Authors

Shara K. Mohammed

Georgios Dimitrakis

Barry J. Azzopardi



Abstract

A limited number of studies are available in literature on the small bubbles which create from gas-very high viscosity oils interaction and its contribution to the gas holdup in the system. The rate of small bubble formation has an important impact on heat and mass transfer in many chemical and industrial processes. The work presented in the current paper provides unique information on the formation of bubbles of millimetre diameter in high viscosity oil. A column of 290 mm diameter and Silicon oil of 330 Pa.s viscosity, were employed besides Electrical Capacitance Tomography and a high-resolution camera to investigate the characteristics of the small bubbles. Mechanism of bubble generation, effect of gas injection time and flowrate were studied. The average void fraction, total gas-liquid height, overall Probability Density Function (PDF) profile, small bubbles volume fractions and diameter were measured. Small bubbles generate from the eruption of large bubbles, at gas injection nozzles, coalescence of large bubbles, and at liquid bridges at transition to churn flow regime. Properties and concentration of the small bubbles are controlled by the location of the bubble generation, gas flowrate, and gas injection time. Small bubbles contribute by 6.6- 30% to the total gas holdup. Bubble diameter increased from 0.68 mm to 0.75 mm and decreased from 1.1 mm to 0.75 mm at the top and the bottom sections of the column respectively after 60 minof gas injection.

Citation

Mohammed, S. K., Hasan, A. H., Dimitrakis, G., & Azzopardi, B. J. (2022). Small bubbles formation and contribution to the overall gas holdup in large diameter columns of very high viscosity oil. International journal of multiphase flow, 152, Article 104104. https://doi.org/10.1016/j.ijmultiphaseflow.2022.104104

Journal Article Type Article
Acceptance Date Apr 15, 2022
Online Publication Date Apr 17, 2022
Publication Date 2022-07
Deposit Date Apr 28, 2022
Publicly Available Date Mar 29, 2024
Journal International Journal of Multiphase Flow
Print ISSN 0301-9322
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 152
Article Number 104104
DOI https://doi.org/10.1016/j.ijmultiphaseflow.2022.104104
Keywords High viscosity oil; Small bubbles formation; High resolution camera; Gas holdup; Electrical Capacitance Tomography
Public URL https://hull-repository.worktribe.com/output/3985161

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