How to make home bio fuel using cooking oil

project for tanso or other experimentalists

Anybody can make biodiesel. It's easy, you can make it in your kitchen
-- and it's BETTER than the petro-diesel fuel the big oil companies
sell you. Your diesel motor will run better and last longer on your
home-made fuel, and it's much cleaner -- better for the environment and
better for health. If you make it from used cooking oil it's not only
cheap but you'll be recycling a troublesome waste product. Best of all
is the GREAT feeling of freedom, independence and empowerment it will
give you. Here's how to do it -- everything you need to know.

Three choices
1. Mixing it
2. Straight vegetable oil
3. Biodiesel or SVO?
Three choices
There are at least three ways to run a diesel engine on biofuel using
vegetable oils, animal fats or both. All three are used with both fresh
and used oils.

Use the oil just as it is -- usually called SVO fuel (straight
vegetable oil);
Mix it with kerosene (paraffin) or petroleum diesel fuel, or with
biodiesel, or blend it with a solvent, or with gasoline;
Convert it to biodiesel.
The first two methods sound easiest, but, as so often in life, it's not
quite that simple.

1. Mixing it
Vegetable oil is much more viscous (thicker) than either petro-diesel
or biodiesel. The purpose of mixing it or blending it with other fuels
is to lower the viscosity to make it thinner so that it flows more
freely through the fuel system into the combustion chamber.

If you're mixing veg-oil with petroleum diesel or kerosene (same as #1
diesel) you're still using fossil-fuel -- cleaner than most, but still
not clean enough, many would say. Still, for every gallon of vegetable
oil you use, that's one gallon of fossil-fuel saved, and that much less
climate-changing carbon in the atmosphere.

People use various mixes, ranging from 10% vegetable oil and 90%
petro-diesel to 90% vegetable oil and 10% petro-diesel. Some people
just use it that way, start up and go, without pre-heating it (which
makes veg-oil much thinner), or even use pure vegetable oil without
pre-heating it, which would make it much thinner.

You might get away with it with an older Mercedes 5-cylinder IDI
diesel, which is a very tough and tolerant motor -- it won't like it
but you probably won't kill it. Otherwise, it's not wise.

To do it properly you'll need what amounts to an SVO system with fuel
pre-heating anyway, preferably using pure petro-diesel or biodiesel for
starts and stops. (See next.) In which case there's no need for the
mixes.

Blends with various solvents and/or with unleaded gasoline are
"experimental at best", little or nothing is known about their effects
on the combustion characteristics of the fuel or their long-term
effects on the engine.

Higher viscosity is not the only problem with using vegetable oil as
fuel. Veg-oil has different chemical properties and combustion
characteristics from the petroleum diesel fuel for which diesel engines
and their fuel systems are designed. Diesel engines are high-tech
machines with very precise fuel requirements, especially the more
modern, cleaner-burning diesels (see The TDI-SVO controversy). They're
tough but they'll only take so much abuse.

There's no guarantee of it, but using a blend of up to 20% veg-oil of
good quality is said to be safe enough for older diesels, especially in
summer. Otherwise using veg-oil fuel needs either a professional SVO
solution or biodiesel.

Mixes and blends are generally a poor compromise. But mixes do have an
advantage in cold weather. As with biodiesel, some kerosene or
winterised petro-diesel fuel mixed with straight vegetable oil lowers
the temperature at which it starts to gel. (See Using biodiesel in
winter)

More about fuel mixing and blends.

2. Straight vegetable oil
Straight vegetable oil fuel (SVO) systems can be a clean, effective and
economical option.

Unlike biodiesel, with SVO you have to modify the engine. The best way
is to fit a professional single-tank SVO system with replacement
injectors and glowplugs optimised for veg-oil, as well as fuel heating.
With the German Elsbett single-tank SVO system for instance you can use
petro-diesel, biodiesel or SVO, in any combination. Just start up and
go, stop and switch off, like any other car. Journey to Forever's
Toyota TownAce van uses an Elsbett single-tank system. More

There are also two-tank SVO systems which pre-heat the oil to make it
thinner. You have to start the engine on ordinary petroleum diesel or
biodiesel in one tank and then switch to SVO in the other tank when the
veg-oil is hot enough, and switch back to petro- or biodiesel before
you stop the engine, or you'll coke up the injectors.

More information on straight vegetable oil systems here.

3. Biodiesel or SVO?
Biodiesel has some clear advantages over SVO: it works in any diesel,
without any conversion or modifications to the engine or the fuel
system -- just put it in and go. It also has better cold-weather
properties than SVO (but not as good as petro-diesel -- see Using
biodiesel in winter). Unlike SVO, it's backed by many long-term tests
in many countries, including millions of miles on the road.

Biodiesel is a clean, safe, ready-to-use, alternative fuel, whereas
it's fair to say that many SVO systems are still experimental and need
further development.

On the other hand, biodiesel can be more expensive, depending how much
you make, what you make it from and whether you're comparing it with
new oil or used oil (and depending on where you live). And unlike SVO,
it has to be processed first.

But the large and rapidly growing worldwide band of homebrewers don't
mind -- they make a supply every week or once a month and soon get used
to it. Many have been doing it for years.

Anyway you have to process SVO too, especially WVO (waste vegetable
oil, used, cooked), which many people with SVO systems use because it's
cheap or free for the taking. With WVO food particles and impurities
and water must be removed, and it probably should be deacidified too.

Biodieselers say, "If I'm going to have to do all that I might as well
make biodiesel instead." But SVO types scoff at that -- it's much less
processing than making biodiesel, they say.


If you want to make it yourself, there are several good recipes
available for making high-quality biodiesel, and they say what we also
say: some of these chemicals are dangerous, take full safety
precautions, and if you burn/maim/blind/kill yourself or anyone else,
that will make us very sad, but not liable -- we don't recommend
anything, it's nobody's responsibility but your own.


Where do I start?
Start with the process, NOT with the processor. The processor comes
later.

Start with the new fresh oil, NOT with waste vegetable oil (WVO), that
also comes later.

Start by making a test batch of biodiesel in a blender using 1 litre of
fresh new oil. If you don't have a spare blender, either get a cheap
second-hand one, or, better, make a simple Test-batch mini-processor.

Keep going, step by step. Study everything on this page and the next
page and at the links in the text. There are checks and tests along the
way so you won't go wrong.

Go on, do it! Thousands and thousands of others have done it, so can
you. Get some methanol, some lye and some new oil at the supermarket
and go ahead -- it's a real thrill!

Here's the recipe. Or just keep reading, you'll get to the recipe in a
minute anyway.

What's next?
Learn, one step at a time. It's all quite simple really, very few
biodiesel homebrewers are chemists or technicians, there's nothing a
layman can't understand, and do, and do it well. But there is a lot to
learn. You'll find everything you need to know right here. We've tried
to make it easy for you. You start off with the simplest process that
has the best chance of success and move on step by step in a logical
progression, adding more advanced features as you go.

"I am a pipe welder who knew nothing about chemistry but I have learned
a lot from this website. It's set up for someone who has never had a
chemistry class (me). If I can understand this anyone can." -- Marty,
Biofuel mailing list, 23 Oct 2005


"For anyone starting out or still in the R&D phase of scaling up and
tweaking the process to improve quality, disregard anything other than
the tried and tested directions at JtF. Print them out. Read them and
then re-read them. Follow the instructions, don't add or subtract
anything and you will be making quality biodiesel." -- Tom, Biofuel
mailing list, 5 Nov 2005


"My best advice is to follow explicitly the instructions on the J2F
website starting from the begining and you will do just fine. In my own
journey of discovery I learned this. You cannot afford to cut corners.
Don't be tempted to use less than accurate measures and think that it
will be alright. There is no cheating." -- Joe, Biofuel mailing list, 4
Jan 2006
This is how it works -- comment from a Biofuel list member:

"Your website is very well done. I appreciate the layers of technical
complexity. You have progressively more technical information layered
in an escalating and logical fashion. I like the links as each new item
is introduced, the user can click for more specific information on a
topic and it opens in a new window. This eliminates the tediousness of
having to constantly backtrack to where the new concept was
introduced."

The process
Vegetable oils and animal fats are triglycerides, containing glycerine.
The biodiesel process turns the oils and fats into esters, separating
out the glycerine. The glycerine sinks to the bottom and the biodiesel
floats on top and can be syphoned off.

The process is called transesterification, which substitutes alcohol
for the glycerine in a chemical reaction, using lye as a catalyst. See
How the process works

Chemicals needed

The alcohol used can be either methanol, which makes methyl esters, or
ethanol (ethyl esters). Most methanol comes from fossil fuels (though
it can also be made from biomass, such as wood), while most ethanol is
plant-based (though it is also made from petroleum) and you can distill
it yourself. There is as yet no "backyard" method of producing
methanol. But the biodiesel process using ethanol is more difficult
than with methanol, it's not for beginners. (See Ethyl esters.)

Ethanol (or ethyl alcohol, grain alcohol -- EtOH, C2H5OH) also goes by
various other well-known names, such as whisky, vodka, gin, and so on,
but methanol is a poison. Actually they're both poisons, it's just a
matter of degree, methanol is more poisonous. But don't be put off --
methanol is not dangerous if you're careful, it's easy to do this
safely. Safety is built-in to everything you'll read here. See Safety.
See More about methanol.

Methanol is also called methyl alcohol, wood alcohol, wood naphtha,
wood spirits, methyl hydrate (or "stove fuel"), carbinol, colonial
spirits, Columbian spirits, Manhattan spirits, methylol, methyl
hydroxide, hydroxymethane, monohydroxymethane, pyroxylic spirit, or
MeOH (CH3OH or CH4O) -- all the same thing. (But, confusingly,
"methylcarbinol" or "methyl carbinol" is used for both methanol and
ethanol.)

You can usually get methanol from bulk liquid fuels distributors; in
the US try getting it at race tracks. With a bit of patience, most
people in most countries manage to track down a source of methanol for
about US$2-3 per US gallon.

For small amounts, you can use "DriGas" fuel antifreeze, one type is
methanol (eg "HEET" in the yellow container), another is isopropyl
alcohol (isopropanol, rubbing alcohol), make sure to get the methanol
one.

Methanol is also sold in supermarkets and chain stores as "stove fuel"
for barbecues and fondues, but check the contents -- not all "stove
fuel" is methanol, it could also be "white gas", basically gasoline. It
must be pure methanol or it won't work for making biodiesel. See
Methanol suppliers

Methylated spirits (denatured ethanol) doesn't work; isopropanol also
doesn't work.

The lye catalyst can be either potassium hydroxide (KOH) or sodium
hydroxide (caustic soda, NaOH).

NaOH is often easier to get and it's cheaper to use.

KOH is easier to use, and it does a better job. Experienced
biodieselers making top-quality fuel usually use KOH, and so do the
commercial producers. (KOH can also provide potash fertiliser as a
by-product of the biodiesel process.)

With KOH, the process is the same, but you need to use 1.4 times as
much (1.4025). (See More about lye.)

You can get both KOH and NaOH from soapmakers' suppliers and from
chemicals suppliers.

NaOH is used as drain-cleaner and you can get it from hardware stores.
It has to be pure NaOH. Shake the container to check it hasn't absorbed
moisture and coagulated into a useless mass, and make sure to keep it
airtight.

The Red Devil-brand NaOH lye drain-cleaner previously sold in the US is
no longer made. Don't use Drano or ZEP drain-cleaners or equivalents
with blue or purple granules or any-coloured granules, it's only about
half NaOH and it contains aluminium -- it won't work for biodiesel.

CAUTION:
Lye (both NaOH and KOH) is dangerous -- don't get it on your skin or in
your eyes, don't breathe any fumes, keep the whole process away from
food, and right away from children. Lye reacts with aluminium, tin and
zinc. Use HDPE (High-Density Polyethylene), glass, enamel or stainless
steel containers for methoxide. (See Identifying plastics.) See Safety

See also Making lye from wood ash.

Chemicals for WVO

Isopropanol for titration is available from chemicals suppliers. Some
people have used the other kind of Dri-Gas, which is isopropanol, but
they found that it's unreliable. Best get 99% pure isopropanol from a
chemicals supplier. 70% pure isopropanol is also said to work, but we
found it didn't give satisfactory results.

Contrary to rumour, "phenol red", sold by pool supply stores and used
for checking water, won't work for titrating WVO, its pH range isn't
broad enough. Use phenolphthalein indicator, specifically 1%
phenolphthalein solution (1.0w/v%) with 95% ethanol. Phenolphthalein
lasts about a year. It's sensitive to light, store it in a cool, dark
place. You can get it from chemicals suppliers. See: Phenolphthalein

Make your first test batch
Here's what you need:

1 litre of new vegetable oil, whatever the supermarket sells as cooking
oil
200 ml of methanol, 99+% pure
lye catalyst -- either potassium hydroxide (KOH) or sodium hydroxide
(NaOH)
blender or mini-processor
scales accurate to 0.1 grams, preferably less -- 0.01 grams is best
measuring beakers for methanol and oil
half-litre translucent white HDPE (#2 plastic) container with bung and
screw-on cap
2 funnels to fit the HDPE container
2-litre PET bottle (water or soft-drinks bottle) for settling
two 2-litre PET bottles for washing
duct tape
thermometer
See Accurate measurements

All equipment should be clean and dry.

For methanol, you can use "DriGas" fuel antifreeze from an automotive
store. One type of DriGas is methanol, another is isopropanol, make
sure to get the methanol one. Also try "stove fuel" from hardware
stores or home centres (but check the contents to make sure it's pure
methanol, it could also be "white gas", which is gasoline and doesn't
work), or try a chemicals supply company. See Methanol suppliers

You can get lye at hardware stores, or from soapmakers' suppliers (try
online). KOH lye works better than NaOH. "Red Devil" lye drain-cleaner
is no longer made. Don't use Drano or ZEP drain-cleaners or equivalents
with blue or purple granules or any-coloured granules, it's only about
half NaOH and it contains aluminium, it won't work for biodiesel. Shake
the container to check it hasn't absorbed moisture and coagulated into
a useless mass, and make sure to keep it airtight.

1. Safety

Read and observe the Safety instructions below.

2. Lye

You need to be quick when measuring out the lye because it very rapidly
absorbs water from the atmosphere and water interferes with the
biodiesel reaction.

Measure the lye out into a handy-sized lightweight plastic bag on the
scales (or even do the whole thing entirely inside a big clear plastic
bag), then close the lid of the container firmly and close the plastic
bag, winding it up so there's not much air in it with the lye and no
more air can get in. Have exactly the same kind of bag on the other
side of the scale to balance the weight, or adjust the scale for the
weight of the bag.

How much to use. NaOH must be at least 96% pure, use exactly 3.5 grams.
If you're using KOH it depends on the strength. If it's 99% pure (rare)
use exactly 4.9 grams (4.90875). If it's 92% pure (more common) use 5.3
grams (5.33). If it's 85% pure (also common) use 5.8 grams (5.775). Any
strength of KOH from 85% or stronger will work.

3. Mixing the methoxide

Use the "Methoxide the easy way" method -- it's also the safe way.
Here's how to do it.

Measure out 200 ml of methanol and pour it into the half-litre HDPE
container via the funnel. Methanol also absorbs water from the
atmosphere so do it quickly and replace the lid of the methanol
container tightly. Don't be too frightened of methanol, if you're
working at ordinary room temperature and you keep it at arm's length
you won't be exposed to dangerous fumes. See More about methanol.

Carefully add the lye to the HDPE container via the second funnel.
Replace the bung and the screw on the cap tightly.

Shake the container a few times -- swirl it round rather than shaking
it up and down. The mixture gets hot from the reaction. If you swirl it
thoroughly for a minute or so five or six times over a period of time
the lye will completely dissolve in the methanol, forming sodium
methoxide or potassium methoxide. As soon as the liquid is clear with
no undissolved particles you can begin the process.

The more you swirl the container the faster the lye will dissolve. With
NaOH it can take from overnight to a few hours to as little as
half-an-hour with lots of swirling (but don't be impatient, wait for
ALL the lye to dissolve). Mixing KOH is much faster, it dissolves in
the methanol more easily than NaOH and can be ready for use in 10
minutes.

4. The process


Using a blender. Use a spare blender you don't need or get a cheap
secondhand one -- cheap because it might not last very long, but it
will get you going until you build something better.

Check that the blender seals are in good order. Make sure all parts of
the blender are clean and dry and that the blender components are
tightly fitted.

Pre-heat the oil to 55 deg C (130 deg F) and pour it into the blender.

With the blender still switched off, carefully pour the prepared
methoxide from the HDPE container into the oil.

Secure the blender lid tightly and switch on. Lower speeds should be
enough. Blend for at least 20 minutes.

Using a mini-processor. Follow the instructions here and improvise
where necessary -- there are many ways of building a processor like
this.

Proceed with processing as above, maintain temperature at 55 deg C (130
deg F), process for one hour.

4. Transfer

As soon as the process is completed, pour the mixture from the blender
or the mini-processor into the 2-litre PET bottle for settling and
screw on the lid tightly. (As the mixture cools it will contract and
you might have to let some more air into the bottle later.)

5. Settling


Freshly made biodiesel, 20 minutes after processing

Allow to settle for 12-24 hours.

Darker-coloured glycerine by-product will collect in a distinct layer
at the bottom of the bottle, with a clear line of separation from the
pale liquid above, which is the biodiesel. The biodiesel varies
somewhat in colour according to the oil used (and so does the
by-product layer at the bottom) but usually it's pale and yellowish
(used-oil biodiesel can be darker and more amber). The biodiesel might
be clear or it might still be cloudy, which is not a problem. It will
clear eventually but there's no need to wait.

Carefully decant the top layer of biodiesel into a clean jar or PET
bottle, taking care not to get any of the glycerine layer mixed up with
the biodiesel. If you do, re-settle and try again.

6. Quality

Proceed to the wash-test to check the quality. If your biodiesel
doesn't pass the test, here's what to do next.

7. Washing

If it passes the wash-test then wash the rest of the biodiesel. See
Washing. For washing use the two 2-litre PET bottles in succession,
with half a litre of tap water added for each of the three or four
washes required. Pierce a small 2mm hole in the bottom corner of each
of the two bottles and cover the hole securely with duct tape.

Pour the biodiesel into one of the wash bottles. Add the half-litre of
fresh water.

a. Bubble-washing. See instructions here. Use a small aquarium air-pump
and an air-bubbler stone -- cut the threaded lid off the wash bottles
if necessary to get the stone in. After washing and settling, drain off
the water from the bottom of the bottle by removing the duct tape from
the hole. Block it again with your finger when it reaches the
biodiesel. Transfer the biodiesel to the second wash bottle, add fresh
water and wash again. Clean the first bottle and replace the duct tape.
Repeat until finished.

b. Stirring. See instructions here. If you have a small enough paint
stirrer and a variable-speed drill, cut the lids off the bottles as
above to accommodate the stirrer. Stir until oil and water are well
mixed and appear homogenous. Settle for two hours or more, drain as
above for bubble-washing, repeat until finished.

If you don't have a stirrer, don't cut the lids off the wash bottles.
Add the biodiesel and the water as above. Screw the cap on tightly.
Turn the bottle on its side and roll it about with your hands until oil
and water are well mixed and homogenous. Settle, drain as above for
bubble-washing, repeat until finished.

8. Drying

When it's clear (not colourless but translucent) it's dry and ready to
use. It might clear quickly, or it might take a few days or up to a
week. If you're in a hurry, heat it gently to 48 deg C (120 deg F) and
allow to cool.

9. Congratulations! You have just made high-quality diesel fuel. Say
goodbye to ExxonMobil & Co., you don't need them anymore.

10. Read on!

Next step

Our first biodiesel
This was just an investigative project for us when we made our first
biodiesel more than seven years ago in Hong Kong. Most of the equipment
was rough and improvised. Apart from chemicals and some beakers,
syringes and so on, the only thing we bought was a set of scales.

We got about 60 litres of used cooking oil from Lantau Island's local
McDonald's. There were four 16-litre cans of it, a mix of used cooking
oil and residual beef and chicken fats. Two of the tins were
solidified, the other two held a gloppy semi-liquid. We warmed it up a
bit on the stove (to about 50 deg C, 122 deg F) and filtered it through
a fine mesh filter, and then again through coffee filter papers, but it
was quite clean -- very little food residue was left in the filters.


Used cooking oil from McDonald's.
We'd also bought 10 litres of the cheapest new cooking oil we could
find -- we don't know what kind of oil it was, the tins only said
"Cooking Oil" -- and we used this for our first experiment.

It worked, though two of our first six batches failed. We've learnt a
lot since then. Now it's easy to make high-quality biodiesel every time
without fail. And we don't use open containers for processing now, and
neither should you (see Safety, see Processors) -- and mix the methanol
in closed containers too.


Simple, safe, efficient biodiesel processors you can build cheaply and
easily

Practices, knowledge, technology, equipment and safety measures have
all improved tremendously in the years since we brewed our first batch,
thanks mainly to the collaborative work of thousands of biofuellers
worldwide at the Biofuel mailing list and other Internet forums, using
the growing body of information at our website and others.

As a Biofuel list member said in 2002: "I just want to say how
important what you all are doing here is. Closed-system fuel
production, on a local or small regional scale, tied to local
resources, using accessible technologies, and dependent on
entrepreneurial innovation combined with open-source information
exchange -- it's AWESOME. Keep up the good work everyone, before the
planet fries."

Biodiesel from new oil


--------------------------------------------------------------------------------

Make your first test-batch using one litre of new oil (fresh,
uncooked). Follow the instructions above. Check the quality of your
biodiesel with this basic quality test.


--------------------------------------------------------------------------------

We had difficulty finding pure methanol in Hong Kong, and eventually
paid the very high price of US$10 per litre for 5 litres from a
wholesale chemical supply company. It has to be 99% pure or better.
(See Methanol suppliers)

We used sodium lye drain-cleaner (NaOH, sodium hydroxide) bought in
small plastic containers at a local hardware store, not always very
fresh. (We recommend using potassium hydroxide, KOH, instead of NaOH.
See More about lye.)

We used 2 litres of methanol to 10 litres of vegetable oil, and 3.5
grams of NaOH per litre of oil -- 35 grams for 10 litres. (It's better
to start with smaller one-litre test batches.)

We had to be quick measuring out the 35 grams of lye required. Lye is
very hygroscopic, it absorbs moisture from the air; summer humidity in
Hong Kong is usually about 80% at 30 deg C or more, and the lye rapidly
got wet, making it less effective. (See More about lye.)

We mixed the lye with the 2 litres of methanol in a strong, heatproof
glass bottle with a narrow neck to prevent splashing. It fumed and got
hot, and took about 15 minutes to mix. (Use closed containers for
mixing methoxide! See above, Mixing the methoxide.

This mixture is sodium methoxide, a powerful corrosive base -- take
full safety precautions when working with sodium methoxide, have a
source of running water handy.


Midori checks the temperature of the oil.
Meanwhile we'd warmed the 10 litres of new oil in a 20-litre steel oil
drum to about 40 deg C (104 deg F) to thin it so it mixed better (55
deg C, 131 deg F, is a better processing temperature). Don't let it get
too hot or the methanol will evaporate. (Methanol boils at 64.7 deg C,
148.5 deg F.)

We'd made a wooden jig with a portable vice clamped to it holding a
power drill fitted with a paint mixer to stir the contents of the oil
drum. This did a good job without splashing. (Not advised, it's
dangerous to use sparking electric motors such as those in drills for
processing with open containers. See "Simple 5-gallon processor" for a
much better way.)

Stirring well, we carefully added the sodium methoxide to the oil. The
reaction started immediately, the mixture rapidly transforming into a
clear, golden liquid. We kept stirring for an hour, keeping the
temperature constant. Then we let it settle overnight.

The next day we syphoned off 10 litres of biodiesel, leaving two litres
of glycerine by-product in the bottom of the drum.

Biodiesel from waste oil
This is more appealing than using new oil, but it's also more
complicated.

First, check for water content. Used oil often has some water in it,
and it has to be removed before processing. See Removing the water,
below.

Refined fats and oils have a Free Fatty Acid (FFA) content of less than
0.1%. FFAs are formed in cooking the oil, and they interfere with the
transesterification process for making biodiesel. With waste oil you
have to use more lye catalyst to neutralise the FFAs. The extra lye
turns the FFAs into soap which drops out of the reaction along with the
glycerine by-product.

It's essential to titrate the oil to determine the FFA content and
calculate how much extra lye will be required to neutralise it. This
means determining the pH -- the acid-alkaline level (pH7 is neutral,
lower values are increasingly acidic, higher than 7 is alkaline). An
electronic pH meter is best, but you can also use pH test strips (or
litmus paper), or, better than test strips, phenolphthalein solution
(from a chemicals supplier).

You can also use red cabbage juice, which changes from red in a strong
acid, to pink, purple, blue, and finally green in a strong alkali, or
one of the other plant-based pH indicators. See Natural test papers --
Cabbage, Brazil, Dahlia, Elderberry, Indigo, Litmus, Rose, Rhubarb,
Turmeric.

We didn't have a pH meter when we started making biodiesel in 1999 so
we used phenolphthalein solution. Phenolphthalein is colourless up to
pH 8.3, then it turns pink (or rather magenta), and red at pH 10.4.
When it's just starting to turn pink it's reading pH 8.5, which is the
measure you want.

Phenolphthalein lasts about a year. It's sensitive to light, store it
in a cool, dark place.

Don't be put of or frightened away by titration. It's not difficult,
thousands and thousands of non-chemist biodiesel makers have learnt how
to do it without difficulty and use it every time they make biodiesel.
Just follow the directions, step by step. See also More about lye,
Better titration, Joe Street's titrator, Accurate measurements.

Titration


Keith checks the pH of the waste oil.
Dissolve 1 gm of lye in 1 litre of distilled water (0.1% w/v lye
solution, weight-to-volume).

In a smaller beaker, dissolve 1 ml of the oil in 10 ml of pure
isopropyl alcohol. Warm the beaker gently by standing it in some hot
water, stir until all the oil dissolves in the alcohol and turns clear.
(Chopsticks make the best stirrers for titration.)

Add 2 drops of phenolphthalein solution.

Using a graduated syringe or a pipette, add 0.1% NaOH solution drop by
drop to the oil-alcohol-phenolphthalein mixture, stirring all the time.
It might turn a bit cloudy, keep stirring. Keep on carefully adding the
NaOH solution until the mixture starts to turn pink (magenta) and stays
that way for 15 seconds.

Take the number of millilitres of 0.1% NaOH solution you used and add
3.5 (the basic amount of NaOH needed for fresh oil). This is the number
of grams of NaOH you'll need per litre of the oil you titrated.

Our first titration took 6 ml of 0.1% NaOH solution (not very good
oil), so we used 6 + 3.5 = 9.5 grams of NaOH per litre of oil: 95 grams
for 10 litres.




--------------------------------------------------------------------------------

NOTE: Novices should avoid poor-quality oil like this for their first
test-batches with used oil. Find a source of oil that titrates at 2 to
2.5 ml of 0.1% NaOH solution, not more than 3 ml. Leave overcooked oils
with high titration levels for later when you have more experience.
Again, make small one-litre test batches before processing larger
batches of WVO.


--------------------------------------------------------------------------------

Proceed as with new oil, see above: measure out the lye and mix it with
the methanol to make sodium methoxide or potassium hydroxide -- it will
get slightly hotter and take a little longer to mix as there's more
NaOH this time. Make sure the NaOH is completely dissolved in the
methanol.

Carefully add the methoxide to the warmed oil while stirring, and mix
for an hour. Settle overnight, then syphon or decant off the biodiesel.

Check the quality of your biodiesel with this basic quality test.

The first five times we did this, using 10 litres of waste oil each
time, we got biodiesel (a bit darker than the new oil product) and
glycerine three times, and twice we got jelly. The answer is to be more
careful with the titration: do it two or three times, just to be sure.
With poor-quality oils that have high titration levels do bracket tests
as well. Do everything you can to improve the accuracy of your
measurements so you get consistent results. Read on, and you'll learn
how to make high-quality biodiesel every time, without fail. (It's a
LONG time since we made jelly!)

The production rate was less than with new oil, ending with 8-9 litres
of biodiesel instead of 10. With care and experience the production
rate improves.

Moving on to bigger things
When you're confident that you can get good results every time, even
using oil from different sources, then it's time to scale up the
process to provide your fuel needs. Now that you have a feel for the
process and know what to expect, you'll have a much better idea of what
sort of processor you want than if you'd started off building the
processor (as many do) rather than learning the process first. See
Biodiesel processors.

However, one-litre test batches are not just something for beginners.
It's a basic technique you'll always use. Many experienced biodiesel
makers do test batches with each batch of oil. Many not only titrate
the oil every time to calculate the right amount of lye to use, they
also do "bracket" tests in sequence, followed by wash tests. You learn
a lot that way, your fuel gets better, life gets easier.

In fact life is already easier -- people who start off making 40-gallon
batches often never learn the accuracy and discipline that comes from
making one-litre test batches first. Their fuel quality suffers for it,
and when they encounter that inevitable "problem batch", they suffer
for it too.

But if you've followed the instructions here carefully, you'll be
familiar with all the variables, you'll have good methodology, and
you'll be in a much better position to trouble-shoot a problem batch
successfully.

Keep a Biodiesel Journal -- make notes, keep records. Get some small
glass jars and keep samples of all your batches, clearly labelled and
cross-referenced to the notes in your journal. You won't regret it.

When scaling up from small test-batches to a full-sized processor, be
aware that the process will probably need some adjusting. All the
various processing methods use averages and approximations because
processors vary so widely. Use the fuel quality tests to fine-tune it
to your particular processor. See Scaling up.

Removing the water
Water in the oil will interfere with the lye, especially if you use too
much lye, and you'll end up with jelly. Test first for water content --
heat half a litre or so of the oil in a saucepan on the stove and
monitor the temperature with a thermometer. If there's water in it it
will start to "snap, crackle and pop" by 50 deg C (120 deg F) or so. If
it's still not crackling by 60 deg C (140 deg F) there's no need to
dewater it.

See Mike Pelly's recommendations: Removing the water.

Here's another way, from Aleks Kac -- it uses less energy and doesn't
risk forming more Free Fatty Acids (see below) by overheating. Heat the
oil to 60 deg C (140 deg F), maintain the temperature for 15 minutes
and then pour the oil into a settling tank. Let it settle for at least
24 hours. Make sure you never empty the settling vessel more than 90%.

Here's what Biofuel mailing list member Dale Scroggins says about water
removal:

Water in vegetable oil can exist as free water, which will eventually
settle to the bottom of a vessel; as suspended droplets, which may
settle if the oil is heated, or the droplets are coalesced; and as
water in solution with other impurities in the oil. Free water is the
easiest to remove. The droplets are removed most efficiently by
coalescing and draining. Suspended droplets that cannot be coalesced
and water in solution are more problematic.

Boiling off the water is more difficult than it appears on the surface.
Colligative properties of solutions (and some mixtures) can make
removal of the last traces of water almost impossible. Water mixed with
oil will not boil at the same temperature and pressure as pure water.
As water is removed, more heat or lower pressure will be required to
remove more water. If the oil contains salts or semi-soluble fatty
acids, distillation is even more difficult.

As the percentage of water in the solution decreases (its molar
fraction) its vapor pressure will continue to drop. Lowering pressure
in the system alone may be insufficient to sustain vaporization when
the solution becomes concentrated (the molar fraction of the solute
greatly exceeds that of the solvent). Results will vary depending upon
the nature of the water-soluble impurities in the oil. Few solutions
are ideal, in terms of Raoult's law, and in used vegetable oil, there
is no way to know what solutes are in the oil.

The important thing is how well-used, or overused, the oil is.
Titration will tell you that. The higher the titration result, the more
water it's likely to contain, and the more difficult it will probably
be to remove the water.

Start with heating to 60 deg C and settling, as Aleks Kac recommends,
and if that doesn't give satisfactory results, try boiling it off, as
Mike Pelly recommends. Then try processing small test batches of a
litre or less first. If you still have difficulties, try to find
better-quality oil.

Washing
Biodiesel must be washed before use to remove soaps, excess methanol,
residual lye, free glycerine and other contaminants. Some people (fewer
and fewer of them) say washing isn't necessary, arguing that the small
amounts of contaminants cause no engine damage.

Read what the Fuel Injection Equipment (FIE) Manufacturers (Delphi,
Stanadyne, Denso, Bosch) have to say about these contaminants:
Summary -- html
Full document -- Acrobat file, 104kb

See also: Determining the Influence of Contaminants on Biodiesel
Properties, Jon H. Van Gerpen et al., Iowa State University, July 31,
1996 -- 12,000-word report on contaminants and their effects. Acrobat
file, 2.1Mb:
http://www.biodiesel.org/resources/reportsdatabase/reports/gen/gen014.pdf

Myth:

I did notice that a lot of the chemistry in the book was wrong.
His main argument seemed to be against losing the energy in
the methanol that was washed out.

The "energy" does you no good if your particular thermodynamic cycle
can't take advantage of it. What is the cetane rating of methanol?
-- Ken Provost, Biofuel mailing list, "Re: washing?"

Quite so. The cetane rating of methanol is only 3, very low. Low
cetane-number fuel in a diesel causes ignition delay and makes the
engine knock. The high-speed diesel engines in cars and trucks are
designed to use fuels with cetane numbers of about 50. The US biodiesel
standard specifies a cetane number higher than 47, the EU standard
specifies higher than 51. The methanol in unwashed biodiesel doesn't
"make a great fuel anyway". It's also very corrosive. The EU biodiesel
standard specifies less than 0.2% methanol content.

Quality biodiesel is well-washed biodiesel. Filtering it is no use, and
letting it settle for a few weeks won't help much either. Anyway
washing the fuel is easy.

See Washing

Using biodiesel
You don't have to convert the engine to run it on biodiesel, but you
might need to make some adjustments and you should check a few things.

Petroleum diesel leaves a lot of dirt in the tank and the fuel system.
Biodiesel is a good solvent -- it tends to free the dirt and clean it
out. Be sure to check the fuel filters regularly at first. Start off
with a new fuel filter.

If a car has been left standing for a long time with petroleum diesel
fuel in the tank the inside of the tank may have rusted (water content
is a common problem with petro-diesel fuel). Biodiesel will free up the
rust, and it could clog the particle filter inside the tank. At worst
the car simply stops, starved of fuel. It's not a very common problem,
but it happens. See: Biodiesel and your vehicle -- Compatability:
Filters.

A common warning is that biodiesel, especially 100% biodiesel, will rot
any natural or butyl rubber parts in the fuel system, whether fuel
lines or injector pump seals, and that they must first be replaced with
resistant parts made of Viton. But rubber parts in diesel engine fuel
systems have been rare or non-existent since the early 1980s -- it
seldom happens, and when it does happen it's not catastrophic, you have
plenty of warning and it's easily fixed. See: Biodiesel and your
vehicle -- Compatability: Rubber.

See Biodiesel and your vehicle

Safety
Please read this whole section right to the end.

Wear proper protective gloves, apron, and eye protection and do not
inhale any vapours. Methanol can cause blindness and death, and you
don't even have to drink it, it's absorbed through the skin. Sodium
hydroxide can cause severe burns and death. Together these two
chemicals form sodium methoxide. This is an extremely caustic chemical.

These are dangerous chemicals -- treat them as such! Gloves should be
chemical-proof with cuffs that can be pulled up over long sleeves -- no
shorts or sandals. Always have running water handy when working with
them. The workspace must be thoroughly ventilated. No children or pets
allowed.

Organic vapor cartridge respirators are more or less useless against
methanol vapors. Professional advice is not to use organic vapor
cartridges for longer than a few hours maximum, or not to use them at
all. Only a supplied-air system will do (SCBA -- Self-Contained
Breathing Apparatus).

The best advice is not to expose yourself to the fumes in the first
place. The main danger is when the methanol is hot -- when it's cold or
at "room temperature" it fumes very little if at all and it's easily
avoided, just keep it at arm's length whenever you open the container.
Don't use "open" reactors -- biodiesel processors should be closed to
the atmosphere, with no fumes escaping. All methanol containers should
be kept tightly closed anyway to prevent water absorption from the air.

We transfer methanol from its container to the methoxide mixing
container by pumping it, with no exposure. This is easily arranged, and
an ordinary small aquarium air-pump will do. The methoxide is mixed
like this -- Methoxide the easy way, which also happens to be the safe
way. The mixture gets quite hot at first, but the container is kept
closed and no fumes escape. When mixed, the methoxide is again pumped
into the (closed) biodiesel processor with the aquarium air-pump --
there's no exposure to fumes, and it's added slowly, which is optimal
for the process and also for safety. See Adding the methoxide.

Once again, making biodiesel is safe if you're careful and sensible --
nothing about life is safe if you're not careful and sensible!
"Sensible" also mean not over-reacting, as some people do: "I'd like to
make biodiesel but I'm frightened of all those terrible poisons." In
fact they're common enough household chemicals. Lye is sold in
supermarkets and hardware stores as a drain-cleaner, there's probably a
can of it under the sink in most households. Methanol is the main or
only ingredient in barbecue fuel or fondue fuel, sold in supermarkets
and chain stores as "stove fuel" and used at the dinner table. It's
also the main ingredient in the fuel kids use in their model aero
engines. So get it in perspective: be careful with these chemicals --
be careful with ALL chemicals -- but there's no need to be frightened
of them.

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