[Homestead] Waste Vegetable Oil vs. Biodiesel
don.bowen at earthlink.net
Sun Aug 17 08:51:56 EDT 2008
You should be aware that WVO (Waste Vegetable Oil) is not the same as
Biodiesel. WVO is what is in the fryer tank at the local French fry place.
It could be Canola, palm, safflower, Peanut or any number of different plant
extract oils. WVO is then the feed stock for Biodiesel.
To use WVO directly in your engine you must make modifications to your fuel
system. WVO does not flow as easily as Diesel so will plug up your fuel
system when cold. An engine using WVO is started on Diesel (or Biodiesel)
then when warmed up shifted to WVO. Before shutdown it must be switched
back and the fuel system purged of WVO. The first modification is a
separate fuel tank for the WVO. Special fuel lines with water lines are
then run from the tank to the WVO fuel filters and are plumbed into the
engine cooling system. Hot water from the engine warms the fuel lines and
the WVO in the tank. A switch over valve is connected between the WVO
filters and the inlet to the normal engine fuel filters and the fuel lines
from the Diesel tank. The fuel from the fryer tank is filtered before
pumping into the vehicle WVO tank.
Biodiesel does not require any changes to the vehicle fuel system. In
almost all respects it is a direct replacement for Diesel fuel and more
importantly a replacement for heating oil. To make Biodiesel you start with
WVO as a feed stock. The conversion from WVO to Biodiesel is a chemical
process that uses ethanol to clarify and dry WVO to remove the fats which
come out as Glycerin, water, and some other minor waste products. The
process can be done in your garage with home made equipment. It is a
straight forward process but somewhat complex and can be time consuming and
must be done carefully. Ethanol is a hazardous material and must be handled
I do not have the figures at hand but there is not enough fryer oil to
replace Diesel fuel. Producers of WVO are seeing a revenue stream as
Biodiesel becomes more popular and waste haulers are getting into the act.
Airlines are looking into bio jet fuels and with home heating oil prices
between $3 and $4 it could become a moral issue between heating homes or
There ain't no free lunch.
Don Bowen KI6DIU
More information about the Homestead