Water washing
From VO Wiki
Contents |
Water Washing Overview
The theory behind "washing" WVO is that added water will come in contact with solid particles, other water in the oil, as well as water-soluble contaminants (sodium, sugar, etc), attach to them and drag them down to the bottom, separating them out of the mixture.
There are a number of undesirable things in the fryer oil that water will attract.
- Protein. Proteins are chains of amino acids. Many amino acids are charged and most have a dipole moment due to their functional groups. This will attract polar water molecules, and the protein should go with the water. The polar attractions are stronger than gravity, so less dense polar materials are likely to go with the water if not congregating at the interface.
- Salt, ionic, goes with water.
- Starch.
- Sugar, goes with water.
- Water soluble acids.
There are two methods for water washing, mist washing and bubble washing.
Mist Washing
- Need picture of setup
Mist washing consists of using a misting nozzle to spray water over the top of a barrel of WVO. This creates a suspension (a mixture of substances that are immiscible, i.e. they don't desolve in each other.) This water then settles down to the bottom of the barrel where it can be drained off via a valve.
| Pros | Cons |
|---|---|
| Well tested | Time Consuming |
| Water is cheap | Fuel must be dried |
| Wastewater |
Nozzles
Nozzles are available lots of places, including McMaster Carr and Utah Biodiesel Supply. See Links at bottom of page.
 Example mist wash nozzle. |
 120 degree spray cone from a misting nozzle. |
Drying
- Drying after a water wash requires heat, time and gravity to let the settling take place.
- Well washed WVO dries easily.
Diagrams
Bubble Washing
Bubble washing uses air bubblers similar to those found in fish tanks to circulate water in the VO. This is generally the less preferred method since it "stirs up" the mixture instead of letting everything settle naturally like a mist wash.
Pictures:
Links
Lots of good water washing supplies (no affiliation): http://www.utahbiodieselsupply.com/washingsupplies.php
