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How to make Biodiesel
HOW TO MAKE HOMEBREWED BIODIESEL EASILY
This is the easiest most fool proof method for making your first homebrewed few mini-batches of biodiesel. As an added bonus, the only "specialized" equipment required is a thermometer, accurate scales to measure out NaOH (in a pinch a metric teaspoon measure will work), and something to measure out 250 ml of methanol and 1 litre of vegetable oil.
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CAUTION
If you are new to Biodiesel making, a few words of caution are in order:
You will be working with dangerous chemicals. Therefore you must use common-sense.
Methanol is a corrosive, flammable liquid that can be absorbed through skin, by inhalation, or consumption. It can cause blindness and death if care is not taken.
Be careful not to inhale any vapors. Cartridge-based respirators will not filter-out methanol.
Sodium hydroxide (Caustic soda, NaOH, lye) can cause severe burns and death.
Long-sleeve shirt, full shoes and trousers are recommended, no shorts or sandals.
Wear chemical proof gloves, apron, and eye protection.
Always have running water available to wash off any splashes.
Now that I have your attention, just realize that Methanol is the fuel used in most Model airplanes. In the USA methanol is available in small quantities as HEET brand fuel line antifreeze (Yellow bottle)
Lye is an every-day drain cleaner.
Both are freely available in most large shopping centres and are safe when used properly.
Methanol boils at 65 °C. You must mix only when the oil is below 60 °C.
You must use a glass bottle to mix the methanol and NaOH (lye) since NaOH attacks some types of plastic. Always store methoxide in a glass bottle.
Be careful not to allow any water into any steps of this procedure.
Before you make your first batch of Biodiesel you should read Mike Pelly's excellent article about biodiesel. (see external links at the bottom of the page).
Be aware that cartridge-based respirators will not filter-out methanol.
Equipment
- 1-2 litre (1.9 in USA) dry Dr Pepper bottles, with top, both in sound, airtight condition.
- 1-thermometer good to 120 ºC, often candy thermometers will work.
- 1-Scales to measure out NaOH, or in a pinch use a metric teaspoon measure.
- 1-Litre volume measure, and something to measure out 250ml of methanol.
- 1-Bowl/container to mix the methanol and NaOH in.
- 1-Funnel
Ingredients
- 1 litre oil, new or used (New will be more reliable).
- 250 ml methanol. Used in some gas line anti-freeze and as the fuel in some racing cars and model aeroplanes.
- Container of NaOH, also called Lye and caustic soda. Typically used to clean out sinks and drains.
The technique
If using waste oil, take one litre and heat to at least 120 deg c to remove all water. If water is present the oil will spit and pop and carry on. If there is a lot of water this could get very violent, so be careful.
Once the water is gone (Oil becomes calm and there is no more spitting and popping) let the oil cool.
If you are using new oil from the bottle, just heat to around 55 °C after you make your methoxide as there should be no water.
Making the methoxide
Warning: Methoxide is a poison. Be careful not to breathe in the vapors. Wash away any splashes. Cartridge-based respirators will not filter-out methanol. NaOH will attack plastic; it is not advisable to mix methoxide in any plastic.
While the oil is cooling, mix your methanol and NaOH(lye) to form the methoxide.
Use 250ml of methanol. This is more methanol than most people normally use, but will help to ensure success.
If you are using new oil this will require about 4g NaOH (about half a slightly rounded metric teaspoon).
If you are using Used Oil, you should do a titration to determine the correct amount of NaOH, OR just try using 6-7 grams of NaOH (about 1 level metric teaspoon) and hope for the best. I have made hundreds of mini-batches of biodiesel from various types of oil using 6g NaOH and have NEVER had a failed batch. It is very probable that it will work for you too, but I do know of one person who had oil that was so used that it did not work.
Remember, only use a glass bottle to mix the methoxide.
NaOH and Methanol do not readily mix, so if you are doing it by hand, a bit of time and patience is required.
Don't sniff the fumes, mixing outside is recommended.
For quickest mixing, start with the methanol at JUST body temperature (not warm). As you mix, the temperature will increase substantially. This is normal. Make sure ALL the NaOH (lye) is dissolved. Hand mixing can be accomplished using a spoon to stir/crush the NaOH granules; OR placing methanol/NaOH in a glass bottle with a tight top and shaking/ swirling until ALL NaOH is dissolved. This may take 10 minutes or more.
After ALL the NaOH has dissolved, top up to 250ml with fresh methanol, as there may be some evaporation during mixing.
Mixing
When the Oil's temperature has dropped below 60 °C, use a funnel and pour the litre of oil into the dry 2 litre Dr Pepper bottle (in a pinch any other brand of bottle will do).
Take the mixture of methanol/NaOH (commonly called methoxide) and pour on top of the oil using the same funnel.
Remove funnel.
Screw the top down TIGHT onto the bottle.
Shake vigorously for ten seconds/ 40 good shakes. NO significant pressure is generated during shaking.
Now place the bottle on a table and observe the oil change colour from a "Light Chocolate milk to a rich, darker brown." Then, as if by magic, within 10 minutes the by-product (commonly referred to as glycerin) starts to settle out and form an increasing layer on the bottom of the bottle. Be sure to notice that you can see a very definite, slowly sinking line towards the top of the Biodiesel as the glycerol slowly settles.
Within an hour, most of the glycerol will be settled out. This is referred to as separation.
You now have a bottle containing lighter coloured biodiesel on top of a layer of darker glycerol. The biodiesel will be very cloudy, and it will take a day or two more for it to clear. Typically the bottom glycerine layer is about the same or a bit more than the amount of methanol used.
See also
- Biodiesel recipe - overlapping information with this article.
- Biodiesel processor