Filtration of deformable emulsion droplets

Area of Science:

• Colloid and Surface Science
• Fluid Mechanics
• Chemical Engineering

Background:

• Oil-in-water (o/w) emulsions are common in various industrial processes.
• Understanding the behavior of emulsion droplets during filtration is crucial for process optimization.

Purpose of the Study:

• To investigate the growth and behavior of oil-in-water (o/w) filter cakes.
• To determine the relationship between filtration pressure, droplet size, and filter cake properties.

Main Methods:

• Filtration of o/w emulsions with varying droplet sizes on membranes of different pore sizes.
• Measurement of cake desorptivity (S) and filter membrane resistance (R) at different filtration pressures (P).

Main Results:

• Cake desorptivity (S) varied with filtration pressure (P), indicating a transition in oil droplet behavior.
• Oil droplets behaved as rigid spheres at low pressures (P << gamma/a) and became deformable at high pressures (P >> gamma/a), where gamma is oil-water interfacial tension.
• At maximum pressures, the filter cake remained permeable to water, consistent with theoretical predictions.

Conclusions:

• The deformability of oil droplets within o/w filter cakes is pressure-dependent.
• Filtration pressure significantly influences the structure and permeability of o/w filter cakes.
• Theoretical models accurately predict water permeability in o/w filter cakes under high pressure conditions.