Biodiesel Chemistry

I have had quite a bit of conversation regarding biodiesel lately. I guess it would be appropriate to share some of it as some of you might have the same questions.

Q. At what temp will biodiesel plug my fuel filter?
A. This depends on what the biodiesel is made from. Biodiesel is made from oils/fats or triglycerides. On the right of the molecule is the glycerol and the three carbon chains attached to the glycerol are the fatty acids. Notice all bonds in the carbon chains are single bonds. This is called a saturated triglyceride. Bad stuff for your arteries and a solid at room temperature. Unsaturated triglycerides have one or more double bonds and tend to be liquids at room temperature. Biodiesel made from unsaturated oils, e.g. animal fats will form wax crystals at a lower tempterature than biodiesel made from saturated oils, e.g. canola oil.

Q. Can I use a diesel fuel treatment to prevent biodiesel from turning to jelly?
A. Companies such as Enertech and PowerService make fuel treatments for biodiesel. If you read carefully, even their best products either are designed to work on a blend of only B20 or their claims are only valid for plant-based biodiesel. How many of you know what type of oil your biodiesel was made from? The only guarantee you have is putting some fuel in a mason jar and use a thermometer and a freezer to figure out the temp where it starts to cloud up.
Q. How often do I need to change my fuel filter after I start using biodiesel?
A. I don't know. Always carry a spare fuel fiter and the tools to do the job in the trunk :) Pay attention for losses of power under acceleration.