How to make diesel from vegetable oil
What you need
- Waste vegetable oil
- Lye (sodium hydroxide
or potassium hydroxide)
- Alcohol (Methanol or
Ethanol) 15% by volume of the WVO
- Heat (perhaps a calor
gas burner or diesel heater)
- Reaction vessels (perhaps
- Blender (do it by hand
or build something automatic)
- Isopropyl Alcohol (use
- Eyedropper (or any other
type of 1 milliliter dropper)
- pH paper (litmus paper)
gloves, safety glasses, plastic apron
! CAUTION ! !
extreme caution when working with these ingredients.
hydroxide or potassium hydroxide)
very toxic and burns the skin upon touch. It is also extremely
damaging if ingested. Ensure plenty of ventilation and access
to water. Have lots of newspaper and detergent on hand.
alcohol) is toxic. It can
be absorbed by the skin and cause nerve deterioration with
prolonged usage. If splashed in eyes it can cause blindness
and could be fatal if swallowed. Take necessary precautions
when using methanol!
(grain alcohol) is also toxic. It is found in all alcoholic
drinks and gets you drunk. Take necessary precautions when
The make up of the free
fatty acids in vegetable oil changes when it been heated (which is
why cold pressed oils are better for you). Oil which has been used
in cooking will require more of the reactive agents (lye and alcohol)
than fresh oil. It is necessary to determine the exact amount of lye
needed to neutralize the acids otherwise you will make excessive amounts
of glycerin and less biodiesel as a result.
To determine the
quantity of lye to use for your oil
- Dissolve 1 gram lye
in 1 litre of water.
- Dissolve 1ml. of vegetable
oil in 10 ml. Isopropyl Alcohol
- Drop the lye solution
into the oil mixture, one milliliter at a time. After each ml. ,check
the pH level of the oil mixture.
- Continue to add the
lye solution into the oil solution, one ml. at a time until a pH
of 8-9 is reached.
- Write down how many
ml. of the lye solution you needed.
- To determine the proportions
- add 3.5 to the number you wrote down. The result is the number
of grams you need to catalyze each litre of oil.
To make your biodiesel
- Measure a quantity of
oil into a suitable container and heat to 120F.
- In separate container
mix Methanol (15% by weight or 17.2% by volume in relation to the
quantity of oil you are processing) with lye (calculating the amount
using the method outlined above). The lye must be added slowly as
it will become extremely hot. The resulting mixture is Sodium Methoxide.
- Add the mixture to the
heated oil mix vigorously for about an hour. You may want to set
up some kind of mechanical aid to do this, perhaps using cycle power.
- Monitor the rate of
separation by taking samples at ten minute intervals.
- Stop mixing when it
appears that the separation has stopped. Leave the mixture to cool
and settle over night or for at least 8 hours.
- The free fatty acids
(glycerin), will sink to the bottom forming a cloudy layer. On top
will be your biodiesel (methyl esters),
but before using it, any remaining soaps or salts should be removed
(or they may cause engine damage).
- Syphon the methyl ester
into a separate clean container and add water. Gently stir the mixture
then leave it to settle again. When the water has separated from
the methyl esters, drain or syphon the water out from the bottom
of the container.
- Repeat the process until
the rinse water you are removing reaches a pH level of 6 to 7 and
contains no soap bubbles. If white substances form at the bottom.
or any bubbles form at the surface the liquid should be re-washed.
- If the liquid appears
cloudy, then water is being retained. It should be reheated gently
in order to make the water evaporate
Your bio-diesel is now
ready to use :-)
Check out more detailed
instructions elsewhere on the web:
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