Pyrolysis has been used since ancient times to turn wood into charcoal. Today pyrolysis is being developed as a waste to energy technology to convert biomass and plastic waste into liquid fuels - a possible solution to the plastic recycling problem we have in the world today.
There are many who say it is not a good solution for various reasons, however on the small scale that Medang is using, it is. Emissions are low (they have been tested), the process takes very little LPG to fuel it and as it is not meant to make profits, but provide a means to recycle plastic and provide a fuel that small islands need we felt it is a great solution for small, remote places.
Of course, this is also alongside education regarding the environment and single use plastics with the ultimate goal being the machine is hardly used by Medang but we then move on to close by islands.
Pyro = heat. Lysis = break down. Pyrolysis involves the molecular breakdown of larger molecules into smaller molecules in the presence of high temperatures in the absence of oxygen. In simpler terms the heat shakes the molecules at very high vibrations and they shake so much that they start to break down into smaller molecules.
Why no oxygen?
As no oxygen is present, the organic material does not combust – which is a big plus for safety!! Instead it decomposes to where it came from – in the case of plastic - crude oil which can then be refined further.
The machine on Medang basic process explained:
The plastic is heated in the melting chamber to 400C where it is becomes a gas and passes into the second chamber, cooling to form crude oil.
Crude oil is a mixture of comparatively volatile liquid hydrocarbons; compounds composed mainly of hydrogen and carbon, though it also contains some nitrogen, sulfur, and oxygen and can be refined to form petrol, diesel and kerosene.
The second chamber of crude oil is then heated and at different temperatures, different fuels are formed. When heated between 150-200C petrol as gas goes through to the condenser to cool, at 250C – 300C kerosene is produced and 300C above diesel. Yield is 25% petrol, 15% kerosene and 50% diesel
We then open all the valves for cleaning machine with a compressor.
The process takes approximately 4 hours overall.
To Change The Earth - One Island at a Time