Natural oil (petroleum) is a mixture of many components. A well-known component of course is the gas or diesel used in our cars. A less well known component is naphtha. Naphtha is a mixture of hydrocarbon molecules that can be saturated (only single bonds between the carbon atoms) or unsaturated (double or even triple bonds between the carbon atoms. Naphtha is used as a precursor for plastics. For example the plastic poly-ethylene is a plastics that is formed when the naphtha mixture is subjected to a process called cracking (breaking up the larger molecules in smaller ones). This gives in first instance the molecule ethane that can subsequently be polymerized under formation of poly-ethylene, a plastic used in an almost endless variety range of products such as in toys, plastic garbage sacs and electrical isolation of wires. 

 

Because plastic is so widely used it leads at the same time also to a lot of plastic waste (plastic packaging materials, plastic bottles, toys etc). A Swiss company, Innovation Solar/Diesoil, is now doing exactly the opposite as the process described above: they have developed a process that will convert plastic waste materials into diesel fuel. 1000 kilograms of plastic will yield about 850 liter of diesel and all this at a cost price of only 26 Eurocents per liter. Recently a Dutch company (Petrogas) announced a big order to build 15 units that can turn plastic into diesel oil based on this chemical process.  

 

Is this not something? Sounds almost like a perpetual process…….

My question to the reader is: how will the thermodynamic balance (both energy and entropy) be for this reaction: 

Petroleum —> Plastic —>  Diesel oil

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