Tap to Read ➤

How to Make Biodiesel at Home

Rita Putatunda
It is time to switch on to alternative sources of energy, in order to save the precious fossil fuels and decrease the level of pollution caused by the latter. This HelpSaveNature article provides you with essential information regarding the procedure to make biodiesel, all by yourself at home.

Did You Know?

Biodiesel can be made from a variety of sources apart from waste or soybean vegetable oil. The examples of such sources include making this fuel from Jatropha seeds, algae, fungi, hydrogen-powered fuel cells, ground coffee powder, and animal fat.
Switch on the news on TV, open the newspapers, or browse the net―one of the hottest topics being discussed is the adverse effects of pollution on the environment, people, and animals. From smog to acid rain, and global warming to respiratory diseases, fossil fuels are the main culprit. However, there is a clean and viable alternative fuel source―biodiesel.
If people learn how to make it by themselves, not only can they have all the energy they need, but also not harm their health and the environment. Apart from being safe, this type of fuel is also a cheaper alternative. Plus, it is one of the best ways to lessen our dependency on foreign oil.

What is Biodiesel Fuel?

It is a vegetable oil-based fuel, which can be used to run an unmodified engine, whether it is a truck, boat, bus, or car. While it is usually derived from canola oil, recycled fryer oil can also be used to make it. It can be used in its pure form, or even mixed with regular diesel. According to many environmentalists, this is the fuel of the future.
Biodiesel is one of the alternative fuels that has been tested the most thoroughly, and the accompanying results have shown that while this type of fuel performs just as well as petroleum diesel, it is a far more environment-friendly than the latter type.

Making Biodiesel at Home

Essentially, biodiesel is derived by a chemical process known as transesterification. This basically involves the replacement of the glycerol component of the oil being used with an alcohol, which is done in the presence of a catalyst. Although it may sound complicated, making biodiesel at home is quite a simple process.
Farms all over the world have been using it for several generations; it is only becoming popular in the mainstream because of the increasing need felt for finding viable alternatives to fossil fuels.
By using easily available ingredients, simple tools, and uncomplicated techniques, one can make it at home, thus, reaping the fuel cost-cutting benefits of its production.

Method 1

This technique is useful for those who want to produce biodiesel at home in a large quantity. It is a bit complicated and requires one to take many safety precautions.
Things Required
  • A large bucket
  • A big bag for filtering the oil
  • Catalyst like sodium hydroxide or potassium hydroxide (the latter is better)
  • Methanol, waste, or new vegetable oil
  • Processor for heating and mixing
  • Isopropyl alcohol
  • Measuring cylinders
  • Titration apparatus (burette, pipette, conical flask, beaker, etc.)
  • Phenolphthalein indicator
  • Distilled water (DW)
  • Respirators that are chemically resistant
  • Long-sleeved gloves
  • Eye protection like safety goggles, etc.

1. Firstly, you need to filter the oil before starting with any kind of complicated process. For this, a simple way is to hang a porous bag onto a pole, and keep a large bucket below it. The oil is poured into these bags and gets filtered, accumulating in the bucket below.
2. After you have collected a substantial amount of oil in the bucket (say about 20 liters), take some in a beaker as a sample for titration, which is the next step in this process.
3. As the oil is used in bulk quantity, it is important to find out the amount of catalyst to be added. A wide deviation from the actual amount can cause the reaction to get spoiled. For this, an oil sample is tested for measuring its acidity or the amount of fatty acids present in it by a reaction with sodium hydroxide.
4. Mix 1 ml of lye with 1,000 ml of DW. This gives 0.1 molar NaOH. Fill this lye in the burette, and remove the air pockets.
5. Now, mix about 5 ml of vegetable oil with about 25 ml of methanol in a conical flask with the help of a pipette, and add a couple of drops of phenolphthalein to this mixture. Titrate it against the NaOH solution from the burette, and keep swirling till the mixture in the flask turns faint pink.
At this point, the acid in the oil has been neutralized, and the reaction is complete.

6. Note down the reading of the amount of lye used, and find out the required quantity of this compound with the help of the following formula:
Number of Moles (N) = Volume (V) x Molarity (M)

For example, if neutralizing 25 ml oil with methanol requires about 5 ml of lye (0.1 molarity), then the concentration of the latter would be:
No. of moles (NaOH) = 25 x 0.1 = 0.25 moles

This provides us with a rough idea of the amount of chemicals required for making the biodiesel.

7. After this, the filtered oil is taken and added to the biodiesel processor. You can use a large amount of oil (about 5 gallons) using this method to prepare an equivalent amount of biofuel.
8. Heat it till about 150°F, and let it cool down for some time. In a separate container in the processor, the methanol and lye solutions are mixed, thus, forming the catalyst.
9. Using the appropriate connections, this mixture is added to the vegetable oil, starting the reaction that takes place at least a couple of days to be completed. During this time, periodically rotate the closed container for efficient mixing of the oil with a catalyst.
10. After the addition is done, leave the container undisturbed for a few days. A dark glycerin layer will start emerging at the bottom, leaving a cloudy brown-colored liquid above it, which is the biodiesel. It will appear if left undisturbed for more time.
11. This fuel is then extracted by careful separation with the help of suction pumps and other such methods. It is still dark and cloudy, and hence, needs a bit of washing with distilled water.
12. For this, put it in the rotating container, and add water with the ratio―500 ml of water for 1 liter of biofuel. Very gently, rotate the container for about a minute or so, and stop the process. The water will get separated from the oil, removing the impurities with it, and will appear brown-colored and muddy.
13. Collect the filtered oil, and repeat the process until a clear layer of water is obtained. This is the quality of biodiesel that is required to be obtained, wherein it can be used for your vehicle.

Method 2

Things Required
  • Vegetable oil (preferably soybean oil)
  • A vessel for making the fuel
  • A settling tank
  • Filtering system
  • 95% pure sulfuric acid
  • 99% pure methanol
  • Prepared mixture of methoxide
  • Measuring cylinders, beakers, and pipettes.

1. Filter the oil in order to get rid of all the particulate matter, like bits of fried food leftovers. Use a number of filtering screens. If you want to avoid this step of the process, you can just buy unused oil.

2. Heat the oil up to about 60°C for about 15 minutes, in order to remove any water that might be present in it.
3. Then, put the oil in a settling tank, and let it stand out for 24 hours to allow it to separate. Either drain out the water from the top or from below.

4. Next, the oil should be measured precisely and heated until all the solids melt. It is important to measure it correctly so that the other ingredients that are added are also in proper proportions.
5. Then, using a ratio of 8% to the total amount of oil, add methanol that is at least 99% pure. The higher the purity of the methanol, the better.

6. Keep blending the methanol in the oil for about five minutes. At this stage of the procedure, the mixture of oil and methanol will look cloudy.
7. Next, for every 1 liter of oil, add 1 ml of 95% pure sulfuric acid. Remember to be very careful by taking every safety precaution possible while handling sulfuric acid because it can be extremely dangerous. Heat this mixture up to 35°C, and keep stirring it.
8. Then, remove it from the source of heat, and keep stirring it gently for 2 more hours. Let it rest for about 8 hours. If you find that any of the mixture has solidified while it had been resting, reheat it lightly.
9. Put half of the 12% volume of methoxide mixture into it, stir for 5 minutes, and let the oil settle down. The cloudy layer will start becoming clear, and this is the biodiesel portion of the mixture that will separate from the glycerin. The latter forms a darker portion at the top, while the biofuel forms the light-colored brownish layer at the top.
10. The next step is called washing, wherein this fuel is filtered many times with water and other filtering equipment so that the impurities are removed, resulting in a clean biodiesel. Then, it can be blended with petroleum diesel too in appropriate proportions, and finally used for the vehicle.

Method 3

Things Required
This is a very simple procedure to make biodiesel and requires easily available equipment.
  • A bottle of vegetable oil (used or new)
  • Sodium hydroxide or lye
  • Methanol
  • Funnel
  • Stove or any heating equipment
  • Glass container
  • Non-aluminum lid
  • Safety goggles or eyewear
  • Hand gloves with long sleeves
  • Digital scale to accurately measure the weights
  • Respirator
Make sure that the place where you are undertaking this procedure has a good source of ventilation.

1. Firstly, in the glass container, take about 300 ml of methanol. Add about 2 tsp. of sodium hydroxide or lye to this alcohol in the container.
2. Now, you have to make sure that the lye solution completely dissolves in this mixture; for this activity, use a stirrer to swirl the mixture. Fix the non-aluminum cap over the container, and keep this mixture aside. The alternative to this is to mix the methanol and sodium hydroxide in a blender.
3. Now, take the vegetable oil in a metal container by using a funnel, and heat it till about 150°F. Let it cool down a bit, and pour it in a 3-liter transparent bottle.
4. Now, add the mixture of sodium hydroxide and methanol to this oil in the bottle using a funnel. Be careful while doing this step, as both the contents of the mixture are extremely harmful if they come in contact with the skin and eyes, or even if inhaled.
5. After the solution is added, tightly seal the bottle, and shake it for about a minute. Keep the bottle on a flat table, and observe the change in the vegetable oil density. At the bottom, a darker layer of glycerol will start forming, separating out from the above lighter layer of vegetable oil diesel.
This happens because of the replacement reaction, wherein the glycerin molecule in the oil is substituted by alcohol molecule, thus, forming the desired fuel. At this point, the diesel will be muddy or turbid in appearance.
6. Keep the bottle undisturbed for a few days; the fuel will start to appear clearer as the glycerin layer finally settles down.

7. The biodiesel can be removed by using a funnel, or also can be separated by using a pipette.

Tips, Safety, and Precautions

  • Try out this process in a small amount at first, say about 1 liter. Once you do that, you will know what to look out for when you handle a larger amount.
  • The chemicals used in this process are hazardous; hence, you need to take every precaution before making it at home.
  • The alkali catalyst used (NaOH or KOH) is caustic in nature, and can cause extreme irritation if it comes in contact with the skin and/or the eyes.
  • Methanol can cause instant blindness, and hence, it is a very harmful type of alcohol. It can be easily absorbed through the skin, and can also cause death in extreme circumstances.
  • When the added catalyst reacts with the oil and methanol mixture, sodium methoxide gas is generated. The fumes of this gas are very toxic, acting as a nerve paralyzing agent if inhaled. Hence, ensure to use an respirator that can block any unwanted fumes and volatile materials.
  • Lastly, if you are not confident enough, consult an expert on this subject.
Though manufacturing biodiesel at home is not a difficult task, one needs to have patience in order to produce usable quantities of this fuel. Things can go wrong at any step, and hence, it will be unlikely that you will get the perfect quality biofuel at the end.
If you follow all the steps correctly and take all the safety precautions, it will be fairly smooth for you to produce mass quantities of this type of fuel, which ultimately will help our planet Earth from an environment-friendly point of view.