General Recommendations for Demulsifying Oil/Water Emulsions
The following guide might help you to find a treatment to separate oil droplets from water. This experience is mostly from hydrocarbon oils in refineries.
There is not a single treatment that always works; we have to try a combination of potential treatments to find the best for each case.
Demulsifying Oil: General information
Demulsification can be done by:
1. Addition of heat
2. Mechanical agitation
3. Chemical modification of the liquid interface
4. Chemical modification of the continuous phase viscosity
5. Displacement of the emulsifying agent
6. Destruction of the emulsifying agent
7. Reduction of the electrostatic /steric forces.
Coagulants, flocculants and pH correction are our options for achieving #3 -#7. Agitation and heat have to be considered if its possible to do it in the plant.
Demulsifying Oil: Chemical Options
- pH increase. Increasing pH precipitates the emulsifier. We have succeeded at pH >9.3
- pH decrease. Decreasing pH destroys emulsifier.
How low? Depends on the type of emulsifier. Try as low as pH 4.5.
- Adding an inorganic coagulant. Inorganics work in several ways:
- Charge neutralization, displacing emulsifiers.
- Metal ions such as Fe+++, Al+++ in the PACs and Tramfloc® 552 and 554 change the emulsifier into metal salts.
- Increase ionic strength, which decreases demulsifier solubility.
Demulsifying Oil: Tramfloc® 308 Treatment
Tramfloc® 308 is a product to separate emulsified oil from water. Tramfloc® 308 is an emulsion EPAM and generally works without the need of a coagulant. Doses are in the range of 2 -20 ppm. Invert the neat Tramfloc® 308 as any other EPAM. Add the Tramfloc® 308 directly to the oily substrate heated to the process field temperature, mix well until phase separation occurs.
Demulsifying Oil: Other Treatments
- The best results are with Tramfloc® 550 Series, Tramfloc® 860 Series and Tramfloc® 552, 554, Tramfloc® 304 and Tramfloc® 310.
- Tramfloc® 308 15-100 ppm
- Tramfloc® 864, 865 50-200 ppm
- Tramfloc® 552, 554, 550 25-100 ppm
For charge neutralization & bridging. Try high charged structured cationic
- Tramfloc® 309, Tramfloc® 312, Tramfloc® 324E, 324G
- The “Benzo” radical in the Tramfloc® 300 series seems to help. Try Tramfloc® 305E, 305G.
- Doses: 1.0 – 20 ppm
Demulsifying Oil: Testing Methodology
Use the “Bottle method” and evaluate results by turbidity, % volatile content or total hydrocarbon content.
Try first: Tramfloc® 720 or 860 Series of coagulants alone. Then Tramfloc® 550 series, Tramfloc® 860 Series followed by Tramfloc® 140 series.
Second: Add flocculant over the best coagulant program. Tramfloc® 308 or 141 or 148.
If nothing works. Repeat again, this time increase pH on steps (8.0, 8.5,9.0 9.5….) before adding the coagulant/flocculant
If nothing works. Repeat this time by decreasing pH by steps.
Use heat and agitation if is feasible in the plant process.
Other Potential treatments
- Tramfloc® 554 or 552 and Tramfloc® 148
- Tramfloc® 860 Series plus Tramfloc® 140 Series
- Tramfloc® 860 Series plus Tramfloc® 300 Series plus Tramfloc® 140 Series
- Tramfloc® 860 Series plus Tramfloc® 140 Series plus Tramfloc® 300 Series
- Tramfloc® 140 alone