In a groundbreaking discovery, researchers in India have developed a relatively low-temperature process to convert certain plastic waste into liquid fuel. This discovery may lead to reusing discarded plastic bags and other products to address growing demands for fuel globally, said a study to be published in International Journal of Environment and Waste Management.
Chemist Achyut Kumar Panda of the Centurion University of Technology and Management Odisha, and chemical engineer Raghubansh Kumar Singh of the National Institute of Technology, Odisha, developed a commercially-viable technology for efficiently rendering common polymer, low-density polyethylene (lDPE) into a liquid fuel.
lDPE is used to make container, medical and laboratory equipment, computer components and plastic bags. In its approach, the team heat up the plastic waste to between 400 and 500 degrees Celsius over a kaolin catalyst (a clay mineral containing aluminum and silicon).
This caused the plastic’s long chain polymer chains to break apart in a process known as thermo-catalytic degradation. The process released large quantities of much smaller, carbon-rich molecules.
The scientist used an analytical method called Gas Chromatography-Mass Spectrometry (GC-MS) to characterise these product molecules and found the components of their liquid fuel to be mainly paraffins and olefins 10 to 16 carbon atoms long. This makes the liquid fuel very similar chemically to conventional petrochemical fuels.
Kaolin acts as a catalyst by providing a large reactive surface on which the polymer molecules can sit and so be exposed to high temperature inside the batch reactor, which breaks them apart.