SCINTEX Biofuels Australia - Frequently Asked Questions

Please read these carefully before contacting us with questions.

Will biodiesel block or degrade my fuel system?

The methyl esters in biodiesel have greater solvent properties than petro diesel. These solvent properties are not a problem if their effects on your vehicles fuel system are understood. The increased solvent properties to the Biodiesel can break down carbon deposits which build up in many fuel systems over time. As these deposits are 'cleaned' from the fuel system they will tend to block fuel filters resulting in a larger number of complaints from people with little knowledge on biodiesel. The increased solvent properties of biodiesel can also soften natural rubbers and o-rings over time. Running your vehicle on B100 (100% biodiesel) may accelerate this natural rubber attack when compared to running a blend such as B75 (75% biodiesel, 25% petro diesel). The attack on natural rubber can easily be avoided altogether by replacing fuel lines with synthetic rubber (Viton) lines. Some fuel pumps also contain natural rubber o-rings which can soften and prematurely degrade when compared to running petro diesel. Please note softening of natural rubbers does not occur overnight and many people never report these issues when running a blend of biodiesl/petro diesel. If a fuel pump rebuild is required be sure to request all synthetic rubber (Viton) internals.

How much does biodiesel cost per litre?

Generally you are looking at 25 - 35 cents per L of biodiesel produced. This is assuming you get your oil stock for free and don't include labour. The main variables are the cost of methanol and dry wash (if used). Buying methanol in large quantities or using a methanol recovery system will reduce your production costs.

What are the advantages of dry wash over water washing?

Both dry wash and water wash can be used to remove water soluble impurities from biodiesel and get your fuel up to the satisfactory standards. Dry wash is significantly faster as you dont have to wait for it to separate from you biodiesel. The dry wash process can be completed in as little as 30 minutes including final filtration. Dry wash also reduces the amoutn of biodiesel loss when compared to water washing. If your biodiesel batch has a high soap content or is water washed to vigorously you could end up with an emulsion rendering the batch useless. Water is however far cheaper in comparison.

Can I use an electric drill to mix biodiesel?

You should never use an electric drill or any other device which produces a spark near methanol. If you have an air compressor a pneumatic drill with a long lead is ideal. In our experience little agitation is required to successfully make biodiesel. If you are making small batches of 50L or less a good hand stir with a spatula at the start and every 15 minutes is plenty.

What temperature should I heat my oil to make biodiesel?

For the standard based catalysed transesterification reaction a temperature of 50-55°C is suitable. Its is not recommended you heat your oil/methanol mixture above 55°C. Methanol′s boiling point is 64.7°C and approaching this temperature increases the risk of fume inhalation and methanol vapour ignition.

Can I use oil from fish and chip shops or restaurants?

Certainly. This is where the majority of small scale producers obtain oil stocks for biodiesel production.

Can I use a mixture of different vegetable oils?

Yes. As long as they are oils derived from plants or animals you can use them to make biodiesel.

Can I use animal fats to make biodiesel?

Yes. However, animals fats and tallows have higher levels of Free Fatty Acids (FFA′s) which makes it more difficult to produce biodiesel. FFA′s when in the presence of base will turn into soaps and can cause havoc with biodiesel production and cleaning. A two stage process involving acid esterification of the FFA's to esters will lower the FFA content allowing for a traditional base catalysed transesterification (with NaOH or KOH) to be performed.

Can I run B100 (100% Biodiesel) in my car?

Yes, B100 will run in your diesel engine very well. Many people choose to blend their biodiesel with some petro diesel. This is popular for a number of reasons;

1. Natural rubber components in the fuel system will last longer by running a blend such as B75.

2. Petro diesel blended with biodiesel will assist in improving the storage life of your biodiesel.

3. A petro diesel and biodiesel blend such as B75 will assist in lowering the gel point (temperature at when the biodiesel starts to become of a gel like consistency) of biodiesel. This can be important for people running biodiesel in colder climates.

How long can I store Biodiesel before using it?

Biodiesel should be used within 6 months but can be left for up to a year. Your biodiesel will last longer if stored in a well sealed vessel where water or air cannot penetrate. You should always refilter your biodiesel before putting it into your vehicle. Straight vegetable oil of Used vegetable oil will last for years as it contains natural antioxidants, these are broken down in the biodiesel making process and your fuel will start to degrade and oxidise. It is possible to buy additives to enhance the storage life of your biodiesel.

Do our SCINTEX biodiesel kits come with all the chemicals required to make biodiesel?

No. You will be required to source your own Methanol or Potasium Hydroxide or Sodium Hydroxide. This is due to the high costs of shipping dangerous goods. The best way to find these chemicals is to search the phone book or internet for chemical suppliers in your area. Remember the more pure the chemicals you get the better your biodiesel will be. 99% pure Methanol is recommended.

How do I dispose of waste glycerol?

Waste glycerol can contain left over methanol, Potassium or Sodium Hydroxide as well as other impurities, making it quite dangerous to the environment. For protocols on disposing of chemical substances you should consult your local council. Often there will be a place at your local dump.

What micron should I filter my biodiesel to?

Many modern car fuel filters are rated as low as 5 Microns. It is recommended you filter to at least 5 microns or preferrably 1 micron to ensure your oil is free from particulate matter. Always refilter your biodiesel prior to putting it in you vehicle, particularly if it has been standing for a while. Small particles in your biodiesel will tend to aggregate over time and even though you previously filtered to 5 microns larger particles may now exist.