Bubble Washing Biodiesel

By Rick Da Tech


bubble washing biodieselBubble washing is more aggressive than mist washing. It is done by adding a layer of water beneath the biodiesel and forming air bubbles in the water. The water is dragged up into the biodiesel in a small layer around the air bubble, which falls back down through the biodiesel when the bubble bursts at the top of the tank. The size of the bubbles and the volume of air will determine the aggressiveness of the wash. Small bubbles with low flows are not very aggressive, but large bubbles with high airflows are very aggressive. If the wash tank is not sealed and used as a first wash technique it can release significant amounts of methanol into your workspace area and create a safety issue. This method uses less water than the mist wash technique.


Bubble washing notes:

Cheap Aquarium Bubbler

Cheap Aquarium Stones tend to melt in biodiesel. You might get a couple of batches through before you have to clean out the green goo in the bottom of your wash tank.



bronze exhaust muffler bubble stones

These bubble stones are actually exhaust mufflers for compressed air tools and have lasted several years. They are available from McMaster-Carr for a reasonable price.


plastic exhaust muffler bubble stones

These Air Tool Exhaust Mufflers are available from MSC Industrial Supply and are made of polyethylene.

This is a wooden bubbler available at Utah Biodiesel Supply

This Bubbler is polyethylene tubing poked full of pin holes. If you look closely at these two videos, you can not only see the air bubbles rising to the top and bursting, but you can also see water filled bubbles falling down through the biodiesel once the air has escaped.

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