Chemical process transforms plastic waste to fuel

Researchers at Purdue University have developed a new chemical process to convert polypropylene and other polyolefin waste plastic into fuel and other new products.

Polypropylene is used in everything from food containers to furniture and makes up around 23 per cent of all plastic waste. The conversion process relies upon selective extraction and hydrothermal liquefaction. In the study, model polypropylene (PP) was converted into oil using supercritical water at 380−500°C and 23MPa. Up to 91 per cent of the model PP was converted into oil at 425°C with a 2−4 hour reaction time or at 450°C with a reaction time of around one hour.  

Once the plastic is converted into naphtha (a mixture of hydrocarbons), it can be used as a feedstock for other chemicals or further separated into specialty solvents or other products. According to the researchers, clean fuels derived from the polyolefin waste generated each year could theoretically satisfy four per cent of the annual demand for petrol or diesel fuel.