EMULSIFICATION PROCESS

TECHNICS AND APPARATUSPresented by: TRINH Anh Phong

trinhanhphong@gmail.com

1.CLASSIFICATION OF PROCESS

Required energy for emulsification maybe carried out by different ways exist many processes.

One classification based on mechanism is: shearing and cavitations

Shearing: turbine, helix, rotor-stator, grinder.

Cavitations: ultrasounds, high-pressure homogenizer.

2. HOW TO PRODUCE AN EMULSION

2 steps: mixture dispersion and homogenization

PROCESS OF EMULSION FABRICATION

DISCONTINUOUS PROCESS

Oil phase and water phase preparation Dispersion Homogenization Cooling Finishing

CONTINUOUS PROCESS

Harder than discontinuous process. Must consider pump system and flow rate

control system. Oil phase and water phase are always

agitated. Dispersion stage: static mixer Homogenization: rotor-stator, grinder, high-pressure homogenizer

3. APPARATUS

IMPELLER TYPES DISPERSION MACHINE HOMOGENIZER OPERATING PARAMETERS

3.1 IMPELLER TYPES

AXIAL FLOW IMPELLERS

Solid dispersion, gas inducement, heat transfer,..

RADIAL FLOW IMPELLERS Low to medium

viscosity fluids. Most effective for gas-

liquid and liquid-liquid dispersion.

Provide higher shear and turbulence with lower pumping compared to axial impellers

HYDROFOIL IMPELLERS

Where axial flow in important and low shear is desired.

Flow is more streamlined in direction of pumping and vortex systems are not as strong as pitched blade turbine

HIGH SHEAR IMPELLERS

Run at high speed and used for addition of second phase in grinding, making emulsion, pigments dispersion.

High intensity of turbulence at vicinity of impeller.

3.2. DISPERSION MACHINE Principal and mechanism: to favor rupture (radial

agitation); to assure circulation to distribute a narrow droplet size.

Generally, the more difficult the dispersion, the more intense the shearing.

Technology: Rushton turbine or paddle turbine (strong shearing); axial mobile (easy dispersion) such as helix mobile (propeller).

Emulsion properties: size 10-100 m quite high

PADDLE TURBINE, RUSHTON TURBINE & HELIX

DIFFERENT FLOW PATTERNS

3.3. HOMOGENIZER

Principal and mechanism: Reducing droplet size to m. Force liquid through a zone at which it is tolerated a very high velocity gradient.

Technology: rotor-stator; colloidal mill. Emulsion properties: very fine droplets.

Can be used directly or after preemulsification stage.

ROTOR-STATOR

COLLOIDAL MILL

3.4. CONTACT OF PHASES

4. TANK & IMPELLER DIAMETER

If too low, most of light phase stay on the surface

If too high, the heavy phase is centrifuged and light phase rests along the agitator shaft.

It should have baffles

D

5. HIGH PRESSURE HOMOGENIZER

Principal and mechanism: forcing the two fluids or a coarse premix to flow through an inlet valve, into a mixing chamber, under the effect of a very high pressure.

widely used for producing dairy and food emulsions.

Pressure: 80MPa, 100MPa, 350MPa.

Emulsion properties: very fine diameter

Convenient for low and medium viscous media.

EXAMPLES

6. STATIC MIXER

Principals and mechanism: composed of immobile elements end to end. Each has particularly geometry to divide and recombine the fluid.

Technology: Efficiency depends much on flow types (laminar or turbulence). Ex: Kenics, Lightnin, Sulzer SMX.

Emulsion Properties: very fine droplets (1m) with narrow distribution.

7. ULTRASOUND Principals and

mechanism: frequency 16kHz 1MHz.

Wave generate instability at liquid-liquid interface, then droplet formation;

Bubble cavitations near the drop will break the droplets

MEMBRANE EMULSIFICATION forcing the dispersed phase to

permeate into the continuous phase

through a membrane having a uniform pore size distribution.

dependent on many parameters such as membrane properties, fluxes, and formulation, all influencing the emulsion size distribution.

Usually, the drop size is proportional to the pore size

MICROCHANNEL EMULSIFICATION

MEMBRAN EMULSIFICATION

THANK YOU FOR YOUR ATTENTION