15 February 2007 -- It is quite right that easy things are hard to explain.

Einstein had the same problem with explaining E=mc2 for a long time and at the end he gave ups and decided to explain E=hf.

It took the Nobel prize committee 12 years to understand the simple equation before giving Albert Einstein a Nobel prize (my teacher used to say they did so to hide their ignorance).

Making biodiesel from used vegetable oils is simple as. You do not even have to spell the term transesterification correctly.

What sets new Zealand farmers apart from farmers in other countries is their ingenuity, hands on approach to technical problems and can do attitude towards problem solving. Above all that very desire of running a self sustainable farm.

Not being afraid of doing the hard yards.

Though I must admit that lately some of these qualities are thinning out. This newish breed of farmers is becoming a little more interdependent to the point of self-complacency.

They talk about economics and productivity and things that keep the bean counters happy. Helping the environment and land sometimes is being heavily compromised and that is sad.

Biodiesel seems to be one of the hot topics among the farming communities but to my horror very few farmers are actively involved in making and using their own biodiesel from used fish and chip oil or from tallow, animal fat.

No good grizzeling about fuel prices, it is better to light a candle than curse the darkness.

This article will endeavor to explain the process of making small batches of biodiesel at home.

There are no mystery chemicals that you have never seen used before. Most plumbers and farmers use 50% caustic soda also known as drain cleaner.

To make biodiesel you will need 100% Caustic soda and that is available at all farming stores, fresh methanol from gas stations or from petrol heads.

Methanol is a good solvent too. Its flash point is 63-65 C so be careful with open sparks. Work in open air or well ventilated area. You will also need a thermometer and pH paper from the local chemist.

To make a two litre batch you will need following equipment (tick list):

* Empty juice bottle made from strong plastic ( 3L capacity or larger)
* Thermometer and pH paper
* Funnel
* Empty white wine glass bottle
* Gloves
* Safety glasses
* Towels
* Lemons
* Ice cream container with ice cold water
* Beaker or a coffee cup
* 500mL methanol
* 10g caustic soda
* 2L used oil ( or raid the kitchen pantry when wife is out )
* bucket of hot water to warm up the oil

Squeeze two fresh lemons in the ice cream container with cold water ( a simple acid to wash your sins away) or add three spoons of vinegar. If caustic soda spills on your skin then wash it with cold lemon water and then under the running water. The pH (acid level) of the lemon water will be around 4.

Pour 500mL of the methanol into the empty wine bottle. Avoid contact with the skin.

Record the temperature …….C

Add 10 g of caustic soda

And gently mix for 5 minutes by swirling or using a stick.

You will feel the temperature of the solution will rise (yours too). Record temp…..C

It is an exothermic reaction therefore an increase up to 8C is normal.

Make sure most of the caustic soda has dissolved. It is not easy as we are dealing with organic and inorganic compounds here, as a marriage between two different cultures always have few underlying reservations.

Leave the Methoxide to settle so that it becomes less cloudy. Measure its pH (will be around 13-14, very corrosive stuff)

Warm up the oil in the hot water.

Pour 2L warm oil in the plastic juice bottle ( Just Juice or Charlie are strong enough).

Add 450 mL Methoxide into the warm oil. ( save 50mL for later use)

Place the lid and shake gently for 5 minutes. Or stir with a stick.

Note the colour changes taking place in the bottle.

Measure the pH ( it will be 10-12)

Give another shake for 5 minutes.

And leave it in the warm water for 20 minutes.

In the meantime, Clean up the mess. Wash hands in the lemon water first to neutalise any caustic on the skin, do other chores to make yourself useful around the house.

After 30 minutes or so look at the bottom of the bottle. You will see a darker layer of GLYCEROL. Measure the pH of the top surface of the RAW BIODIESEL (it will be 9-10). Add the remaining methoxide into the juice bottle and allow the bottle to settle down for 15 minutes.

You will see the clear separation, and around 8-10% GLYCEROL/raw glycerin in the bottom. If your oil was too dirty then there may be third white layer of liquid soap. Leave the unit there for overnight so that all the glycerol particles settle well. Gravity and density of the liquids will do the trick.

Now start thinking of making larger quantity of biodiesel, say 20L - 50L, without using any electrics, bells and whistles in a humble kiwi farmers way. Simple common sense and experience will suffice here. Have a chat with few mates, toss around few ideas and call me if you get stuck.

The top layer is your raw biodiesel in the juice bottle and will be looking transparent by now. Do the decanting, i.e take the top layer out leaving behind the glycerol. It can be used as it is, straight into the fuel tank of your diesel tractor, truck or car. Good to have 30% biodiesel mix with 70% dirty diesel for better combustion.

Some people do want to do an extra step i.e washing the biodiesel. Really there is no need for this if you are using biodiesel for the larger diesel engines and your mix were right and you waited for at least 12 hours to let the biodiesel settle well.

Well, washing is simple as it sounds. Just add slow stream of 2L warm water into the raw biodiesel and let it settle again. Now you really have a good biodiesel. Check its pH It will be 8 or under. Do not worry it is just fine. Decant it and use the milky water in the garden or on the compost.

* Glycerol sells at $2/L in the chemical market place. You need to purify your glycerol at least 80% before selling it to the chemical industries.

We at ENERGY TECHNOLOGY EDUCATION CENTRE , Pukekohe NZ, run nationwide and now internationally hands on workshops on many aspects of renewable energy. In Dec and Jan we are running some workshops at Chicago IL, USA and will be back in NZ during Feb 07 For details

EMAIL: melvindin@varsity.co.nz,

ph/fax 09 238 1080,

mob 021 215 2850 Melvin Din

Dip Tchg, Cert Adult Edn & Trg

International workshop presenter and energy consultant