As interest continues to grow, our database of questions and answers will continue to grow, giving us the ability to provide you with the answers to the most frequently asked questions. Here then are the most frequently asked questions:
- Does biodiesel gel in certain temperatures?
Biodiesel manufactured from soy or yellow grease has a cloud and pour point of approximately 32F while yellow grease and tallow ranges in the fifty degree area. When blending biodiesel manufactured from any feed stock it is equally important to access the best base stock (relating to cold properties) with your biodiesel.
- How much sulfur is in biodiesel?
- Are there specifications for biodiesel that can be compared against diesel fuel specifications?
Yes, compare ASTM D 6751 (biodiesel B100 specification) with ASTM D 975 (generic diesel fuel specification). You can find a biodiesel typical specification by clicking the biodiesel basic icon found on the bottom of either the Ask Ben website or NBB website.
- What has been done to keep biodiesel blends flowing in the cold weather months?
A number of additives are available for improving the low temperature operability of diesel fuels. These additives include pour point depressants, filterability or flow improvers that lower CFPP, and wax anti-settling additives. The effectiveness of the additives depends on the properties of the fuel. So, you must first understand what your base diesel cold weather specifications are (cloud point, pour point and cold filter plugging point). All additives must be introduced into the diesel fuel before the fuel reaches its cloud point, and must be properly blended. Block and filter heaters and indoor vehicle storage can also help ensure smooth winter operation...
- How many bushels of soybeans are required to manufacture one gallon of biodiesel?
1 bushel equals 1.5 gallons of biodiesel
- I am a petroleum marketer, is there any incentive or credit to encourage me to start up a biodiesel program in my area?
At this time the biodiesel mixture credit affords blenders of record a distinct credit of $1.00 per gallon for agri-biodiesel and for recycled oils (yellow grease) once blended into on- or off-road diesel. This type of program will assist you in recovering any costs associated with preparing for distribution. Beyond this federal credit you should contact your local government to see if there is any specific biodiesel legislation in your state which may be beneficial to your potential intervention with biodiesel. Finally, biodiesel affords you an opportunity to offer your customers a cleaner burning environmentally friendly liquid fuel option which would enhance your total offering to your valued customers. Visit www.biodiesel.org to learn more about the exciting biodiesel industry.
- What is transesterfication?
It is the refining or processing method which raw soybean oil or other feedstock’s are taken and processed in ASTM D 6751 biodiesel. Biodiesel can be manufactured from vegetable oils, recycled cooking grease, or animal fats. These feedstocks are reacted with methanol in a chemical reaction called transesterfication to form fatty acids methyl esters (FAME). The various feedstocks’ can contain up to 14 different types of fatty acid chains with specific fatty acids and their proportions varying with feedstock.
- What is the minimum and maximum flash point of B20?
The definition of flash point is the lowest temperature at which the application of the ignition source causes the vapors above the liquid to ignite. Biodiesel flash point can be close to 300F but has been as low as 260F. Diesel fuel on the other hand is rated to be 140F. To determine the actual flash point for B20 you would have to average the blends accordingly or better yet, have the sample professionally tested once blended to determine or validate your calculations. Any ASTM testing laboratory can perform flash point testing.
- What is the truth about seals…does everything need to be Viton?
B100 will have a negative impact on Buna and Nitrile seals however Teflon and Viton are more suitable for higher to neat blends. If you plan on using biodiesel at 20% or under you most likely will have negligible headaches with sealing compounds. I would suggest that you click biodiesel basics at www.biodiesel.org for a complete listing of recommended elastomer.
- How do you make biodiesel?
Click the ASK BEN link then biodiesel basics, then production, a complete description of transesterfication with schematics are available.
- What is the best method to test for storage stability of a B20 blend? Does the acid value number tell you anything useful for B20? What would a typical B20 acid number be?
Fuel aging and oxidation can lead to high acid numbers, high viscosity and the formation of gums and sediments that clog filters. If the acid number, viscosity or sediment measurements exceed the limits in ASTM D 6751, the B100 is degraded to the point where it is out of specification and should not be used. Most B20 fuel could be a candidate for use of stability additives if fuel is being stored in excess of six to eight months. As biodiesel and biodiesel blends are stored the acid number tends to increase and go out of specification, gums and varnish can form and the viscosity can increase. The ASTM standard to evaluate acid value is ASTM D664 and Kinematic Viscosity, ASTM D445.
- What can you tell me about micro-organisms and biodiesel fuel? Does it cause black, stringy gunk in a fuel tank? How can it be avoided?
I can tell you that if you keep your fuel systems (diesel fuel, kerosene and biodiesel fuel) free of water then you will have no incidence of microbial contamination. Before bugs can become an issue water must be present along with warmer temperatures. For the record biodiesel is no more an incubator for microbes than any other fuel left unprotected from water contamination. Water can enter through the vent cap, in the fuel itself and through the delivery process. Micro-manage your fuel for water before and after each delivery and execute at a bare minimum quarterly fuel management program which will help you have a positive experience with your liquid fuels in general.
- Can you tell me the problems with B100 and yellow metals? Are there any modifications someone can make in order to run it in your home heating oil system?
Use of tanks or lines made of brass, bronze, copper, lead, tin or zinc may cause high sediment formation and promotes filter clogging and is not recommended with B100 or for that matter generic heating oil as well. This is why additive companies are including metal deactivators in premium heating oil packages to tie up the yellow metals so as not to accelerate corrosive activities within the storage tanks which the fuel is stored.
Blends of 5% up to 20% are less of an issue but this is one area that NBB is working on to evaluate the impact of yellow metals with biodiesel. Unless you are prepared to pretty much change your oil lines from copper to stainless, your fuel pump seals to Viton or Teflon I would suggest sticking with B5 as a minimum to a max of 20% biodiesel. There is a comprehensive overview of heating oil and biodiesel at www.biodiesel.org for your review.
- I have heard that biodiesel has 300 percent more lubricity than petroleum diesel. Is this true and if so where can I get information sources to back it up?
Biodiesel is a well known lubricity enhancer. Go to www.biodiesel.org and type in lubricity and you will be recipients of reams of data on the subject. Small amounts of biodiesel as low as 2% can increase a fuels lubricity up to 65%.
- We have been told by some that biodiesel is more corrosive for storage tanks over time than traditional diesel fuel. Is this true and if so why?
This is not true. Both diesel fuel and heating oil as well as biodiesel independently or blended as one fuel are all susceptible to numerous fuel quality deficiencies. In short if fuel systems have water ultimately the diesel fuel user will face micro biologics, corrosive activity and fuel instability. The number one contaminant in fuel is water and it is very important that you make sure if water is in a fuel tank that you immediately get rid of it. Biodiesel is no more a driver in this phenomenon than diesel fuel itself. For more information go to www.biodiesel.org and click "User and Handling Guidelines, 2004" publication which does a great job addressing issues such as this.