"How to make Biodiesel"
to make Biodiesel
Biodiesel forms due to a chemical reaction called
transesterification, meaning that glycerol in the oil
is substituted by an alcohol in the presence of a
catalyst. In our case we use Methhanol and NaOH
(caustic soda) or KOH (caustic potash). In this
"How to" we will do our best to make clear
to you how to prepare a good biodiesel. Don't let
yourself be put off by our method, though. There are
many other ways and tricks to prepare good biodiesel
and you can find much about it at the other websites
The 3 ingredients
primary ingredient is oil or fat. This will be waste
vegetable oil for the average producer at home, which
may be collected for free in most restaurants.
One can, of course, grow rapeseed or Jathropa and
crush it for oil, as often happens in the United
US farmers are nowadays self-supporting with regard to
energy. They use biodiesel in tractors and other
farming machinery and mostly diesel aggregates are
used to generate electricity.
who prepare diesel on a larger scale are able to use
waste frying fat, fish oil, animal fat and several
other kinds of oils. The nice thing about biodiesel is
that you can make it out of so many different
substances, mostly waste products. There is always
something in stock, and even the use of new oil is
The second ingredient is alcohol. Methanol is mostly
used in the application of recycled vegetable oil.
When processing new oil, it is often possible to use
ethanol, but as ethanol is more difficult to handle,
we use methanol here.
like to point out that methanol is a very dangerous
material, as is ethanol. Avoid inhaling and skin and
eye contact, always wear gloves suitable for this
substance, eye-protection and face-mask and always
work in a well-ventilated room.
The last ingredient is the Catalyst. Both KOH
(potassium hydroxide, caustic potash) and NaOH (Sodium
hydroxide, caustic soda) may be used. The advantage of
KOH is that the residual glycerine is much less toxic
than when NaOH is used. In that case, it is even
possible to process the glycerine into artificial
fertilizer. KOH dissolves much more readily in
methanol as well. However, an advantage of NaOH is
that it is very simply and cheaply to get as a
plunger, while it is good to handle. That is why we
use it in this manual.
can always have a go with KOH as well. Take care that
you use NaOH with a purity of 96% or higher. KOH of
that percentage is rather hard to find, but 92% and
85% will work fine as well. Both NaOH and KOH are very
dangerous chemicals. Please take the precautions
mentioned above when using these chemicals.
biodiesel can be derived from many oils and fats,
mostly waste frying oil is used. Restaurants often
have to pay for the removal of their waste oils.
Therefore it is rather simple to collect oil for free
from a restaurant
most convenient way is to collect it in its original
packaging. Oil mostly is supplied in plastic
containers. If your supplier is willing to refill
these containers with the waste oil you are certain
that the oil is not polluted extra by water, dirt and
other externally interfering factors. Another option
is that you provide the restaurant with a barrel to
catch the oil. Obviously, you can spare yourself the
trouble and use new vegetable oil. It simply is for
sale at supermarkets and wholesalers.
The cleaner and newer the
oil, the simpler it is to make high quality diesel.
Its colour and
transparency tell a lot about oil quality. Light
and clear is good; darkand turbid smelly oil is less
suitable to produce biodiesel.When you are not sure of
the oil quality, it is advisable to make first a small
amount of diesel. If this turns out to be good, then you
can process the rest of the oil. Our
manual may seem to be very simple and in fact making
biodiesel is not that difficult. It only becomes tricky
when you have oil of lesser quality, like oil with much
water. Too much water may interfere with the process,
especially when you are using too much of catalyst a
kind of gel may form. One way to
check your oil for water is by heating about half a
liter of oil to a temperature of 50� C. If it starts to
bubble/hiss/crack etc. then the oil contains too much
water. When you do not see any of these phenomenons at
60� C, there is no reason to remove the water.
you are able to process the vegetable oil into biodiesel
you have got to know first how much methanol and
catalyst you need. As far as methanol is concerned you
may always assume about 200-220 ml methanol per litre of
oil. The percentage of NaOH is variable. If new
vegetable oil is processed, then you will require 5 g
per litre of oil to substitute all glycerol by methanol.
If waste oil is used then the same amount of catalyst
will be required plus a certain amount to
neutralize the free fatty acids that are present in the
oil. To this end you will have to determine by way of a
test, called titration, how many of these free fatty
acids (FFAs) are present in your oil.
do you need?
ml isopropyl alcohol, 99%*
(heated to 45� C)
hypodermic syringes to enable dosing the right
pair of scales preferably accurate to 0.1 or
articles will be provided when purchasing a BioKing
procedure is as follows
1 g of catalyst in 1 litre of distilled water, this
solution is the titrant. NaOH is very difficult to
dissolve. This can best be done by putting for
instance 50 ml distilled water into a transparant
bottle, adding the gramme of NaOH, closing the bottle
and shaking it as long as it takes to see no visible
grains and pouring this back into the distilled water.
solution is suitable to carry out titrations in the
following weeks. In order to reduce the chance of
errors, you may consider to dissolve 3 g of catalyst
in 3 litres of distilled water. An error of for
example 0.2 g has less effect that way than in the
case of 1 litre. Cork the botle and keep it well. Take
care when weighing the grains of NaOH that you do not
leave the packaging open. The grains are very quickly
to attract water and will not be fit for use anymore.
The photo on the right shows how the grains look
when they are subjected to a few minutes of oxygen.
Pour 10 ml Isopropyl Alcohol in a glass cup or saucer.
Heat a bit of the oil to be tested to a temperature of 45�
C , mix 1 ml of it with the alcohol and mix well, it
will get a yellowish colour.
The amount of alcohol does not require much precision,
but it is important that you should measure out
exactly 1 ml of oil. An old trick is to suck in a
bubble of air first into the hypodermic and then the
oil, this way you are able to read more precisely.
Add 2-3 drops of PH-indicator solution (phenolphthaleine).
carefully to add the water with the catalyst, keep
swinging the cup. The fluid will colour to a light
pink, but will turn yellow again if you keep swinging.
When the oil with alcohol remains pink for a period of
30 s, you stop adding the solution. Make a note of how
many ml of solution you have used and repeat the whole
procedure once or twice in order to make sure you have
you have a PH-meter at your disposal you can use it
instead of the phenolphtaleine-solution. When the
fluid has reached a PH-value of 8.5, then you have
added enough NaOH-solution.
you need less than 3 ml of the solution then you most
probably have laid your hands on very good oil, 3-6 ml
means that the oil is suitable to turn it into
biodiesel. 6 ml or more implies a poor quality, but
the oil may still be suitable for the production of
biodiesel. Take care when titrating that you should
use each instrument for only 1 agent. We advise to
label all hypodermics, pipettes and other tools in
order to avoid mistakes.
of the titration results, it is advisable to first
process one litre of oil, before turning to the
production of bigger amounts. Should you have
made a mistake somewhere than this will appear now,
this way you avoid that you may have to throw away
maybe 100+ litres of oil because you made a mistake in
one litre of test diesel is easy to make. You start
with heating 1 litre of oil to 45�C, preferably in a
jar or bottle that can be corked. In the
meanwhile you mix 220 ml of methanol with the amount
of catalyst you determined in titration. Put this in a
glass jar or bottle that can be corked well. This mix
is called methoxide.
processing new oil you use 5 g of NaOH per litre of
processing waste oil you take 5 g +1 g for each
ml of catalyst solution you needed for titration. If 4
ml solution was needed, for example then you use
g of NaOH
the methoxide until of the catalyst is dissolved. The
chemical reaction will make the fluid to get hot. When
all grains of NaOH have been dissolved, you carefully
add the heated oil. Subsequently you shake or mix it
all during 10 to 15 minutes.
the oil to rest. In less than an hour already you will
see a separation between biodiesel and glycerine.
test has been successful if you see a distinct
dividing line between the biodiesel and the glycerine,
the amount of glycerine should be about 10% of the
less than 10% glycerine forms, then you probably have
used too little catalyst, carry out a new test with
0.5 � 1 g more of catalyst.
you see a clear layer of soap between the biodiesel
and the glycerine, then you probably have used too
much of catalyst. Carry out a new test with 0.5 - 1 g
less of catalyst.
you see lumps in the biodiesel, then you have bad oil
or the titration was incorrect. Carry out a new
titration and make a new test batch from it. If you
see lumps again, then you better should not use this
the biodiesel to rest for 12-24 hours. Dark coloured,
somewhat viscous glycerine will have formed at the
bottom of the jar, with a distinct dividing line with
the pale fluid above it. The colour of biodiesel
varies and depends on the type of oil that was used,
but is mostly palish yellow. The diesel can be clear,
but this is not required per se, it may be very turbid
as well. Not to worry. Eventually it will become
clear, but there is no reason to wait.
Methanol, Methoxide (Methanol/catalyst-mix), and NaOH
are dangerous chemicals. Before use always read the
safety regulations provided and follow the
instructions on the packaging. Always work in a
well-aired room and always wear personal means of
protection, such as a suitable face mask, gloves and
face protection when working with these materials
make a whole tank
the tank with the amount of vegetable oil
desired, up to a maximum of 150 litres.
on the heating and wait until the oil has
reached the desired temperature of 45� C
heeft bereikt. Turn off the heating
The heating element must never be turned on
when it is not fully submerged in the
liquid, this can damage the element!!!!
the oil is heating you can prepare the
methoxide, this is as follows:
- Fill the
premix-tank with 15 litres of Methanol and the
amount of catalyst desired
- Swith a
wooden or synthetic object, as long as is
needed to dissolve all grains.
the oil has reached the right temperature and
the methoxide is ready, you can start mixing.
To this end you have to open valves A, C and D
and switch on the pump with the button
"Pump 1hr". Open the tap (F) on the
methoxide-tank. The content will mix
gradually with the circulating oil, when the
methoxide has run out you can replenish
methanol until the amount recommended of 220
ml of methanol per litre of oil has been
reached. The oil will be mixed with the
methoxide, during 1 hour exactly, the exact
time needed for a good and complete reaction.
pump will switch off automatically after one
having letting it rest for 1-2 hours, you may
drain the glycerine from the bottom of the
tank. Another 8 hours later you may drain the
last glycerine from the barrel. The biodiesel
is now ready to be washed.
As the BK200 is not
equiped with an automatic stiring device, the content
of the premix-tank is kept small, this is in order to
make the mixing more easy. You will have to pour the
remaining methanol during the mixing of the oil with
methoxide in the little tank.
of the diesel with water is very important for various
reasons. Your biodiesel will probably have a high
alkaline value, because of the fact that non-used
catalyst particles are still in the fluid. By washing
the lye will be removed and the biodiesel will become
PH-neutral (7). While washing we remove furthermore
soap, methanol surplus, solid particles and any other
pollution that may happen to be in our diesel. You may
think: "Methanol is a good fuel, why do I have to
remove it from my biodiesel?" Methanol as such
is a good fuel indeed, but surplus methanol may damage
smaller Bio-King� units are supplied with a built-in
water-mist system, with it we can wash our diesel
effortlessly. It works as follows:
a garden hose to the coupling provided, open the
tap and leave it running for 1 hour, this
will make about 20 litres of water to
"spray" through the mist. The water is
heavier than the diesel and takes, while falling
down, the pollution with it.
Attention: Hot water washes better than
cold water and soft water washes better than hard
In the case of you having problems with the proper
washing of your diesel you may consider using hot
water and a water softener.
the diesel to rest for at least 1 hour, so that
the water can do its job well.
the water at the bottom. Handle things tactfully.
If you open the valve completely it will cause an
eddy causing the biodiesel to be remixed with the
water and this, obviously, will not be your
this process at least twice before the water
leaves the diesel almost clean (PH7). Take care
that all water is drained from the processor. You
would be well-advised to purchase a PH-meter of
PH-indicator paper in order to test your biodiesel.
you can pump the diesel from the BioKing into a
storage tank or the like, again by means of the pump
on the BioKing.
works as follows: You connect a hose to the hose
socket at the filter, open taps A, C and E and start
the pump 'Manual'. The biodiesel will now be pumped
into your storage tank via the filter. Most remaining
water will be extracted from the diesel by the
built-in water separator. There will always remain a
certain percentage of water in the diesel making it
somewhat turbid. It is better to leave the diesel
2 or 3 days in an open tub, this will make the surplus
water to evaporate, this is called drying. You will
see your biodiesel getting more clearly. The drying
can be accelerated by leaving the biodiesel in the sun
to dry or by heating it until a temperature of about
45� C and subsequently letting it cool down in an
open tub. If the diesel turns turbid again after
cooling down, then this means that the diesel has not
been washed properly, wash it again. What
you have now is biodiesel, ready for use. You may use
it purely in your car or if desired, mix it with �Dinodiesel�. In
winter in particular, at low temperatures it may be
sensible to mix 20 to 30% of normal diesel with your
biodiesel. Biodiesel tends to thicken even more than
normal diesel does when it is cold.
can think of temperatures below -5� C. When you are
starting to use biodiesel, it is sensible to begin
with a mixture of 20% biodiesel and 80% normal diesel.
One of the biodiesel�s good properties is that it
cleans your fuel tank and fuel circuit, this makes
that small particles will turn up in your fuel system.
If you were to start immediately with 100% biodiesel
in your car then you will most probably have your fuel
system blocked. Therefore, you will have to increase
the percentage of biodiesel gradually. This way you
can find out at which ratio your car runs best
hope that we have put you on the right way with this
manual in the production of biodiesel. You have seen
that it is not difficult and with the help of the
BioKing and these instructions you will probably
succeed. We cannot guarantee good biodiesel though,
this depends completely on your method and the ratio
of the ingredients. Previously in this manual we have
mentioned a few websites where you can find much on
biodiesel. Study these well. There are other methods
to produce biodiesel with an apparatus such as the
BioKing and these methods may appeal to you more. If
you have any questions on the production of biodiesel
or the BioKing you can always mail to firstname.lastname@example.org
will try and help you as quickly and as well as we can
to get you on your way again.
to simple test your biodiesel
#1 - clarity
an approximately 500ml sample of your fuel in a clear
container. You should be able to read newsprint through
it. If you cannot see through the fuel it's an
indication there may still be water, glycerin,
monoglycerides or diglycerides in your fuel. You don't
want any of these in your finished fuel.
#2 - miscibility
your 500ml sample, mix in about 1 cup of water. Shake
until water mixes with the fuel. Let sit for a few
minutes. The fuel should separate from the water and
there should be no layer of soap between the two layers.
If soap is created, it's an indication further washing
is needed. If the fuel does not separate easily, it's an
indication of poor quality fuel.
#3 - Odor
the fuel, it should have a faint odor of vegetable oil
with no alcohol type smell.
your reaction went according to plan, and the biodiesel
passed the three tests shown above, you can be confident
you have good fuel. However it is possible to run other
tests to be sure. You can test the pH of the fuel
exactly the way you titrated your original oil. Good
biodiesel should have a pH of around 7. You can test the
specific gravity of the fuel with a hydrometer, or you
can even send the fuel out to a lab and have it tested
to see if it meets ASTM D6751 specifications.