Hey, Engine Man – Is Biodiesel More Susceptible to Algae Growth?
Successful Farming Engine Man Ray Bohacz has engine grease and field dirt under his fingernails from a life spent repairing vehicles and running a farm. When he's not busy in the shop, he's working on maintenance articles and videos for Successful Farming magazine and answering questions from readers. The following is a letter Bohacz received from Joe Bonuchi:
I have been told that if large quantities of biodiesel sits in storage tanks for several months that algae will start forming, which will in turn clog fuel filters very fast. I am referring to storage tanks of 1,000 gallons to 3,000 gallons in size sitting for 12 to 24 months. Can you tell me, is this real or a myth?
Response from the Engine Man:
To respond to your question, we first need to define the biodiesel blend. For example, B-20 (20% biodiesel and 80% petroleum diesel) has a storage life similar to traditional diesel. As the amount of biodiesel goes higher to B-100, the storage life goes down. B-100 is more prone to growing algae due to its composition of fatty acids (not to be confused with animal fats). But to be fair, all diesel fuel of any kind has, in theory, a limited storage life. So biodiesel is not that much different. Other factors that impact storage life are the quality of the fuel when made, the temperature of the storage vessel, and the cleanliness of the storage tank.
Biodiesel has a scrubbing ability and will clean both the storage tank and the engine's fuel system. This often clogs the fuel filters on both the storage tank and the engine after the first load of biodiesel is introduced but lessens and totally disappears after all of the residue is gone.
The good news is that there are readily available additives you can put into your bulk storage tank before it is filled with biodiesel. These products will keep the problems at bay for quite some time. One can make a convincing argument, though, that with any diesel fuel (and gasoline for that matter), you don't want to buy more than you can use over about six months. Since there are so many factors that influence the actual storage life of the fuel on your farm, it is a good idea to always try to have fresh fuel.
Do you have a maintenance question? Email Ray Bohacz at SFEngineman@Agriculture.com.