What is an Emulsion Breaker?
Before we delve into emulsion breakers, let’s make sure we’re all on the same page. At its most basic, an emulsion is a mixture of two (or more) liquids that won’t normally mix (i.e., are “immiscible”). Oil and water are a perfect example.
In general, we might expect immiscible fluids to separate on their own—as is the case with the oil and water in the bottle of Italian dressing sitting on the table—or with a little coaxing (as from a centrifuge.)
But the presence of emulsifiers, surfactants, co-surfactants, co-solvents, or other substances can complicate this. That’s because these substances tend to be composed of molecules that have a hydrophilic (“water-loving”) head and a hydrophobic (“water-fearing”) tail. (In many cases, that tail isn’t just hydrophobic, but actually lipophilic—”oil-loving.”)
The emulsifier gathers around the dispersed micro-droplets of oil (as shown on the right of the figure below). Note that the “water-loving” heads point out, toward the water, while the “oil-loving” tails point in, protecting the oil droplet. Instead of drifting together and coalescing into bigger droplets, and eventually forming their own layer, the oil can remain dispersed in solution, free-floating throughout the water.
This results in a “tightly bound emulsion”—one that won’t separate on its own and may even prove challenging to separate with a centrifuge.
This is where the “emulsion breaker” (or “demulsifier”) comes in.
Chemical Emulsion Breakers Help Centrifuges Separate Even Tightly Bound Emulsions
The emulsion breaker behaves exactly the opposite of the emulsifier (hence the name “demulsifier”). It breaks the emulsion up by separating water and oil components. Before dosing, the oil droplets in your fluid are quite scattered (as seen on the far left of the figure above). When the chemistry penetrates the emulsion, it disrupts any hydrophilic/hydrophobic layers protecting these dispersed droplets. The oil droplets can then begin to flocculate and coalesce, forming ever-larger droplets and globules (as illustrated from the bottom up on the middle of the diagram). These larger droplets are much easier to separate and capture via centrifugation.
Emulsion breakers generally make it easier/less energy intensive to separate fluids. But they are especially important in certain industries, like ethanol. DCO (distillers corn oil) has become a vital co-product for most ethanol plants. But the enzyme technology used to increase oil extraction from ethanol stillage tends to trap a good deal of oil in solution, creating extremely “tightly bound” emulsions that resist mechanical separation unless emulsion breakers are used. Many ethanol plants use chemistry like Ascent , which was developed by Trucent and Croda with existing Croda patented and bio-based ingredients, to extract more DCO for less money .