Question about biodiesel.......?

Question

Is there anyone that home brews biodiesel? How can I test my homeade biodiesel to see if it meets the fuel quality standards. Only serious answers please!

Answer 1

The answer to your question depends on where you are located and which fuel quality standard you are working against.

Typical diesel fuel quality looks at :

Density
Sulphur Content
Flash Point
Viscosity
Corrosivity (Cu)
Storage Stability
BTU content
Water Content
Acidity/Alkalinity

These tests will all be relevant for biodiesel.

Density is important because it is a relative measure of fuel energy content - although this is better defined using BTU.

Flash Point is important as it denotes both the relative safety factor for the fuel and, in the case of biodiesel, relative residual methanol content. The flash point should be > 60C

Sulphur content - regulated depending on local laws - usually < 50ppm. Shouldn't be a problem for biodiesel but may be indicative of residual sulphuric acid if using a two stage transester reaction.

Viscosity - important because the fuel system needs to have a relatively low viscosity fluid to operate efficiently. High viscosity is undesirable and viscosity can be affected by choice of base vegetable oil / fat used.

Corrosivity - Important as we don't wish to corrode fuel systems! Also important because if the fuel is corrosive to copper, the most common test metal, it is also likley to have a low stability. Copper ions catalyse the degradation of many fuels and many fuel systems contain copper.

Storage stability - Commercial fuels may be stored for indeterminant amounts of time - a minimum storage stability of 12 - 18 months is desireable.

BTU Content - a measure of the energy in the fuel.

Water content - linked to stability and corrosion but also just not something desireable in the average fuel system.

Acidity/Alkalinity - probably more a question of residual alkalinity in biodiesel as a measure of how well "washed" the fuel is. Probably better to measure Na/K ppm, but this isn't as easy for the "backyarder".

How to test :

You can do Density, viscosity and flash point by relatively simple modifications of the ASTM standard tests. Density is by hydrometer, viscosity by flow comparison with standard diesel and flash point by an "open cup" flash test (long match / small beaker).

The other tests are more difficult and require a full lab.

Answer 2

Find a biochemist to test it, probably at a local college. I would not recommend going to Willie Nelson, since he might not want the competition.

Answer 3

Willie Nelson is the man to get a hold of, he makes it down in texas. check the web for his web site.