Written by Rickdatech

Free Fatty Acids (FFA) are the result of the breakdown of oil or biodiesel.  FFA% is usually used to describe the FFA content of oils, while Acid Number (AN) is commonly used to describe the FFA content of finished biodiesel. With a little math, we can use the same titration procedure we use to titrate WVO to determine FFA% and AN.

Written by Rickdatech

Would you like to estimate how long it should take to heat your oil, theoretically? Depending on the oil it will typically take half as long to heat up oil as water so we use this formula when heating oil.

Time in hours = 0.5 X Number of Liters X Temperature rise in °C / by element wattage

Example = 0.5 * 100L * 20°C / 1500 = 0.67 hours or 40 minutes.

These equations are ESTIMATES. They are close when used on well insulated tanks like water heaters. When heating oil in an container that is not insulated, like a steel drum, heat losses to the air can be significant, sometimes equal to the amount of heat put into the oil.

Written by Rickdatech

Biodiesel can go bad when microbes digest it, when water hydrolyzes it, or when it oxidizes. When bacteria or fungus attacks biodiesel it is always at the place where water and biodiesel meet. . There are microbial tests available at most fuel testing labs. There are also a few on site microbial test kits available on the internet. To prevent infection keep your biodiesel dry. To get rid of an infection requires the use of an antibiotic fuel treatment. Hydrolysis is using water to break the bond between the alcohol and the fatty acid. It is the same process that creates FFA in oil. The only way to prevent it is to keep your oil dry.

Unlike the other methods, oxidation requires oxygen rather than water. When unsaturated fatty acids oxidize, they will break down producing foul smelling acids, like butyric acid. While it may be easy to detect rancid oil, it is a great deal more difficult to predict how long a fuel will last before it goes rancid. The NREL suggests that biodiesel be stored no longer than six months, since the older a fuel is, the more likely it is to break down. We can monitor how fuels age and break down with a few simple tests.

Written by Rickdatech

An Indicator Dye is a substance that changes color with pH. We use them in titration tests to find the equivalence point where we stop the titration.

Written by Rickdatech

Gel Point, Cloud Point, Pour Point. These are the bane of biodiesel. It is the the cause of winter nightmares for homebrewers. It's the reason we leave jars of fuel on the stoop all winter, and the reason why our trucks stop dead in the coldest winter. Most biodiesel has a rather high cloud point. It will gel up quicker than diesel so we will either stop using it or mix it with diesel.

Written by Rickdatech

On the vegetableoildiesel.co.uk forum, they have come up with the AAF method. It basically is you reverse the process around. Add methoxide to the reactor first, then add hot oil slowly to the methoxide.  It speeds up the reaction giving finished product faster than when the other method is used.