Biodiesel is a fuel that has much the same characteristics as normal diesel oil, but as opposed to diesel it is not derived from petroleum but from vegetable oils or animal fat. Generally, vegetable oils are used such as sunflower oil, soy oil, rape oil or palm oil. Used oils may be used likewise very well indeed. To produce biodiesel from these oils, they are subjected to a chemical reaction, which is called transesterification. It is a chemical reaction that makes the glycerol present in the oil to be substituted by methanol, using a lye as a catalyst. Its result is a methyl ester. One of its examples is rape methyl ester (RME). A residue forms due to transesterification, called glycerine. This can be applied in various ways, one can think of such things as making soap.

Why?

Biodiesel's plus-points are obvious: It is biodegradable, it decreases soot-emission with ± 50%, it decreases emission of hydrocarbons and it is CO2-neutral. In addition to these environmental plus-points, it is safe indeed (its flashpoint is ± 170C º) and it is easy to mix with fossil diesel.

Where?

In several European countries, including Austria, Italy, Spain, Frace and Germany biodiesel is seriously applied, with France and Germany as absolute leaders. Over 150,000 cars run on biodiesel in Germany, for instance, and scattered over the country there are well over 1,200 service stations with a biodiesel pump. The reason of the biodiesel success in Germany is the fact that no excise is levied on biodiesel, which makes its price an average of 4-8 cents below that of normal diesel. In the Netherlands we are hopelessly trailing behind in the use of biodiesel. One of its reasons is the uncompromising attitude of the Dutch government towards biodiesel. An example is the fact that it does not intend to lift excises on biodiesel. Eventually they will come round in the Netherlands, mainly due to pressure from Europe and European legislation with regard to biofuels.

How?

Virtually anyone can make biodiesel by means of a very simple process, often compared to brewing beer. It makes that energy-independance is in store for everyone. Biodiesel development is far from over yet and each day new machines and methods are invented. Good sources to keep yourself abreast of things include the Internet sites http://journeytoforever.org/biodiesel.html and http://biodieselcommunity.org. At these sites one can find anything on biodiesel and the like, including excellent recipees and tips on e.g. titration, washing, drying etc.... You can find many magazines as well, such as "Biodiesel Magazine".

We will try to show you the ropes of producing of biodiesel with the BioKing by means of this manual. Our method is one that works nicest for us and is resulting nearly always in a good diesel. Obviously, this is not guaranteeing success. Making good biodiesel mainly requires practice and study. 

How 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 mentioned above.

The 3 ingredients:

Oil

The 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 States.

Many 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.

People 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 cost-effective still. 

Alcohol

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.

We 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.

 Katalysator

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.

You 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.

How to get oil:

Although 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.

The 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.

Oil quality

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 50º 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 60º C, there is no reason to remove the water.

Titration:

 Before 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

What do you need:

10 ml isopropyl alcohol, 99%*

Oil (heated to 45º C)

Phenolphtaleine-solution (0,2%-0,4%)*

Catalyst (NaOH, KOH)*

Distilled water

Some glass saucers

Some hypodermic syringes to enable dosing the right amount.*

A pair of scales preferably accurate to 0.1 or 0.01 g

*These articles will be provided when purchasing a machine

How to simple test your biodiesel

Test #1 - Clarity

Take 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.

Test #2 Miscibility

Using 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.

Test #3 Odor

Smell the fuel, it should have a faint odor of vegetable oil with no alcohol type smell.

Other Tests

If 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.

Web sites for general information about biodiesel

Biodiesel information Web site

Biodiesel Community

Machines examples

12 metric tons per day biodiesel compact stainless steel processor

Hot oil presses