FEATURED TOPIC – PLASTICS RECYCLING
What is hydrothermal liquefaction? DR LEN HUMPHREYS, CHIEF EXECUTIVE OFFICER OF LICELLA HOLDINGS, TELLS WASTE MANAGEMENT REVIEW ABOUT THE NEXT GENERATION OF ADVANCED RECYCLING.
T
he topic of how we use and manage plastic exploded at the beginning of 2018, when China told the world it would no longer accept its plastic waste. The aftershocks were felt by waste contractors, councils and then the public; some councils even paused recycling collection. Fast forward to 2022 and the rapid and systems-wide transformation needed to enable a local circular economy for plastic has not happened. The sad reality is that 87 per cent of plastic is still not recycled in Australia, according to the Plastic Waste Advanced Recycling Feasibility Study: GeelongAltona Industrial Corridor 2021. To achieve the Australian government’s ambitious National Waste Management Target of 80 per cent average resource recovery rate, plastics will require an additional 2.5 million tonnes of recycling capacity – that is a 13-fold increase on what is in place. Advanced recycling is one piece of the puzzle to help achieve this. Also referred to as ‘chemical recycling,’ advanced recycling takes plastic back to its chemical building blocks; oil that can be used back into the local plastic supply chain. Critically, advanced recycling helps close the loop on the 87 per cent of plastic that still is not recycled in Australia each year. Unlike mechanical
42 / WMR / May 2022
From left, Dr Len Humphreys, Trevor Evans Assistant Minister for Waste Reduction and Environmental Management and Lucy Wicks, Member for Robertson with a KitKat recycled wrapper protype made with oil from post-consumer soft plastic collection.
recycling, where plastic needs to be sorted by type, advanced recycling can process mixed plastics, including multilayer packaging. Advanced recycling takes plastic back to the oil it came from, which enables the production of food-grade recycled plastic. It complements mechanical recycling by offering a solution for difficult to recycle plastic that currently goes to landfill or incineration.
A NEW APPROACH While older advanced recycling approaches, such as pyrolysis, are purely thermally based, a lower-carbon
approach has emerged – one that uses water. Hydrothermal liquefaction (or HTL) is the next generation of advanced recycling. Moreover, the most commercially advanced HTL technology in the world is Australian – Licella’s Cat-HTR (Catalytic Hydrothermal Reactor) platform. HTL was developed in a carbon constrained world. It uses hot, pressurised water to recycle more carbon from plastic than pyrolysis, while using less energy to achieve this. In addition, HTL moves hydrogen from the water into the product
