The ingredients are:
Sodium Hydroxide (NaOH) or
lye
Methanol (CH3OH)
And, of course, Veggie oil
(lots of H’s C’s and O’s)
In my case I distill my glycerin so I use 25% methanol by volume, or
250ml per liter of oil. I have made fuel
using as little as 16% methanol by volume but the reaction only goes to about
90% completion making for a more viscous fuel.
If I were to live only in summer-like climates this would be fine and
the cheapest method. Using 25% methanol
yields a 98% complete reaction or better.
Into the methanol goes the
catalyst, in this case lye. 3.5 grams of
lye per liter of virgin oil is the starting point. Now, depending on how much the oil has been
used I will need to add more. My source
is very consistent, so I can count on oil that is about 5 grams per liter once
it’s all mixed together. The way to tell
is to either do a titration on the oil to find out how much more lye is needed,
or to simply make small batches (a liter or less) using progressively higher
amounts of catalyst until a good reaction occurs.
A good reaction will have two
distinct layers: A golden translucent layer on top and a dark brown opaque
layer on the bottom. Pics to
follow. The trick is to use the amount
that produces a good separation but not a cloudy top layer. This may require several batches with ¼ gram
differences to determine. It is also
important to test the oil every time until its quality can be assured. I no longer titrate, but that is because I
have been getting the same oil since April of 2000 and can tell by looking at
it how much lye it needs.
Wanna make more than one
liter? Easy, just multiply everything by
the number liters of oil. I use 165
liters of oil titrating at 5 grams per liter.
So that’s 165*5g lye=825 g of lye (add a few grams more to make up for
what clings to containers). And
165*250ml (or .25 liters)=41.25 liters of methanol.
Once I have all of the
ingredients measured I mix in the lye into the methanol. This step requires caution as the mixed base
is very strong and the fumes are toxic.
After the NaOH is completely dissolved the whole mixture is added to the
veggie oil and mixed again for up to a half an hour. I let this settle for at least 6 hours and
then drain the glycerin. The remainder
is allowed to settle for a few days and then drained again. Then it is transferred to storage.
Finally, NaOH can be replaced
by potassium-hydroxide (KOH) and the methanol can be replaced by ethanol, but
the reaction is much less forgiving of error and requires more of each.