"Washing Biodiesel And Quality Testing Without Headaches and Hassles"

Washing biodiesel is Here.

The No Fluff, No BS Guide to Washing and Quality Testing Biodiesel.

Now You Can Have Quality Biodiesel Even Better Than Some Commercial Dealers!

My methods are So Simple, Anyone Can Do It and Start Saving Money Today.

Bubble Washing Biodiesel:

Simply put, bubble washing biodiesel involves adding water to your biodiesel via a inexpensive air stone and air pump set up to the water portion you can buy at any aquarium store.

The principle involved here is that the water, being heavier than oil, introduced through the air bubbles will first float to the top, then settle through the biodiesel to the bottom, taking the impurities out with it.

The air bubbles will gently agitate both fluids, taking a tiny amount of water and carry it through the biodiesel, picking up contaminants along the way. When the bubble reaches the surface, it bursts, dropping the water, and the water settles to the bottom, taking even more soaps and impurities on its way back down.

Sounds pretty cool, huh? It is, keep reading...

After about 6 hours of this (low-wattage) washing, the air is stopped, then the water is drained, more fresh water is added, and the process repeats. These wash water changes are repeated about 3 times on average- until the water measures the same pH of your tap water, and is perfectly clear. The wash water can be reused a number of times to wash succeeding batches (explained below as Counter Current).

Advantages of Bubble Washing:

Cost: Bubble washing is cheap.
It uses less water than other methods,
It also utilizes very cheap equipment. (aquarium air pump is under $10 new, very easy to find used at flea markets and thrift stores,
It uses very little electricity, (3 watts of electricity).
It is easy to leave the wash unattended (especially with a cheap timer to make the process even more user-friendly).

Disadvantages of Bubble Washing:

If you made a batch of poor quality biodiesel to begin with, bubble washing can agitate the water and the biodiesel too vigorously- causing emulsification of the two liquids.
Emulsification, i.e. "glop" is the quintessential wash problem
The up-side however is that you can use it as a form of bio-diesel test and feedback on your process. Once you know what causes it, it's easy to stay away from.
Not recommended for washing a very small batch

Equipment Needed for Bubble Washing:

Washing Container
Valve (optional) or siphon to drain water from under the biodiesel
Aquarium air pump of at least 3 watts--(if washing a large- 25 gallon or bigger- batch)
Aquarium air stone- the bigger 6 ones sink to the bottom easily, the small ones will need to be weighted down with some washers, and some airline tubing.

Optional Equipment for Bubble Washing:

Cheap timer to turn off air bubbler automatically after 6 hours.

The container:

You can do washing in your processor or in a separate container. I use a 55gallon closed head drum which has been turned upside down (bungs are now on the bottom) and the end without bungs is cut open (sawzall works great for this). I then attach a ball valve to the 3/4 bung and mount the whole thing on a stand (or some cinderblocks, or just even set it on top of a two fullsize American milk crates stacked together to a bucket-clearing height).

Using a separate wash bio diesel container rather than your processor frees up the processor for making and settling the next batch, keeps any residual water out of your next batch, and keeps any glycerine that didnt drain well from contaminating the wash water (which can lead to emulsification)

The rest of the equipment is fairly straightforward.

USING THE CONTAINER

Add 1/3 water to a container with 2/3 biodiesel.
Dribble the water into the tank gently- dont spray it hard from a hose under high pressure.
Drop a bubblestone into the water, turn on the air pump, and let bubble for a few hours. The air pump should be mounted (I use thick wire and sort of tie it to the outside edge of the drum) above the level of the water so that if the power goes off theres no chance of liquid siphoning back into the pump.

The exact amount of time you bubble is not crucial.

We use 6 hours for the first wash, and more for the others. The water will become somewhat saturated in relation to the soaps content of the biodiesel, and will stop taking in any more soaps/contaminants. At this point (6 hours or overnight), turn off the bubbler. It is useful to let everything sit for an hour or several so that the water and biodiesel separate well (optional). This is where the timer is useful- to turn bubbler off and let settle before you get there to drain it. You will then drain the water as much as possible, add more water, turn on the bubbler. This wash water change and overnight bubbling is repeated three or more times, until the wash water is clear and measures the same pH as your tap water.

Courtesy of www.biodieselcommunity.org