Liquid-Liquid Coalescence

The performance of many produced water treatment units and primary three phase separators depends on the coalescence of droplets of dispersed phase with a bulk liquid layer. From a fluid mechanics aspect, coalescence will be a process that is governed by the flow of liquid away from a droplet that is approaching liquid surface. Once the distance between the drop and surface becomes small, surface tension forces will be involved that eventually dictates the time taken for the drop to coalesce. This project will review the current science and the experimental and modeling methods used to validate and study this process. Although the project targets the oil and gas sector, coalescence is something that is critical in a number of industries. If appropriate, a small scale system will be established to measure the time taken and factors that affect the time a droplet of dispersed phase takes to coalesce with a bulk liquid layer.

Your project is to first review the available literature and identify the work that has been done and is being done. Next, to develop an understanding of the processes involved as discrete droplets approach a flat interface. Third to either experimentally model or mathematically model the process to such a degree that allows the data to be used for engineering purposes.

For the experimental part, you will need to develop a droplet generator to produce a droplet of controlled size. This will be released to contact with a stagnant layer of oil and you will be interested in finding the time taken for the droplet to coalesce. Issues will be the presence of eddy currents as the droplet approaches the liquid surface. You will repeat this study for droplets attaching to flat surfaces of different metals.

For the modelling part, you may need to use CFD or develop your own solution tools (possibly with Matlab) to solve a set of equations that describe the process. Your model would need to be validated against experimental data that has been published so a critical task is to review the literature and identify a set of data.

References
The influence of interfacial ageing and temperature on the coalescence of oildroplets in water
Ata, S. ; Pugh, R.J. ; Jameson, G.J.
Colloids and Surfaces A: Physicochemical and Engineering Aspects, 20 January 2011, Vol.374(1-3), pp.96-101[Peer Reviewed Journal]

Effective rates of coalescence in oil–water dispersions under constant shear
Mazumdar, Meenakshi ; Jammoria, Aniruddh Singh ; Roy, Shantanu
Chemical Engineering Science, 10 January 2017, Vol.157, pp.255-263

Supervisor name: 
Graeme White

MSc programme:

Project Type: