Session: 10-09-01: Industrial Flows

Paper Number: 136487

136487 - Mesofluidic Oil-Water Separation 

Effective and rapid separation of multiphase solutions at industrial scales remains a long-standing challenge.  Many two-phase separations are accomplished by static gravitational settling (e.g., oil-water separators, clarifiers, settling tanks, etc.).  Gravitational settling is often slow, if not very slow.  For faster separation, centrifuges that separate much more quickly but with limited throughput can be considered.  Where phase density differences are large (e.g., air versus water), buoyancy forces can be very effective at driving phase separation, but where the densities remain within an order of magnitude, separations are often much slower.  At very small scales, surface forces can be used to drive phase separation, but these techniques often do not translate to high throughput systems.  A rapid high throughput means of inducing phase separation of multiphase fluids remains a perennial challenge.

 

One technique being applied for separating solids, such as blood components or sand particles, from carrier fluids is the use of arrays of aligned posts called deterministic lateral arrays.  Flow through these arrays is used to bump particles to one side in the flow stream to induce separation.  This solid mesofluidic particle separation technique may be useful for separation of deformable particles including separation of oil droplets from water. 

 

We set out to investigate the question:  Can these separators be used to separate oils generally at higher throughput than reported by Dijkshoorn, et al. (2018)?  In this paper, we take an important step toward answering this question.  We use a mesofluidic separator developed by Burns, et al. with an oil-water mixture to (a) confirm that oil-water mixtures do separate and (b) that flows on the order of liters per minute (L/min) can be achieved. 

 

We conducted experiments applying mesofluidic separation for flowing two-phase (oil/water) mixtures.  The purpose of the tests was to determine if water migrates and preferentially exits the separator as an oil-depleted stream and oil preferentially exits as an oil-enriched stream.  To investigate this question, tests were conducted at 5 concentrations and a range of decreasing flowrates.  Experiments were conducted in a flow loop using oil with water as the carrier fluid at room temperature.  The oil-water mixture was circulated through the test loop and through the mesofluidic separator.  During each test grab samples were obtained simultaneously as fluid flowed out of the mesofluidic separator and into the mix tank.  Analysis showed separation of mineral oil from an oil water mixture at flowrates from 1-2 L/min and concentrations from 2-10 wt% oil in water.  Test results showed that separation was achieved over the range of oil-water concentrations evaluated.  We describe the results of these experiments in this paper.  The results show that these mesofluidic separators can be used to separate mineral oil from an oil-water mixture. 

Presenting Author: Judith Bamberger FEDSM2020 Chair and Senior Research Engineer, Pacific Northwest National Laboratory

Presenting Author Biography: Dr Bamberger is a Sr Res Eng at PNNL specializing in multiphase flow and mesofluidic separation.

Authors:

Judith Bamberger FEDSM2020 Chair and Senior Research Engineer, Pacific Northwest National Laboratory
Leonard Pease Pacific Northwest National Laboratory
Michael Minette Pacific Northwest National Laboratory
Carolyn Burns Pacific Northwest National Laboratory