What is hydrothermal liquefaction?

What is hydrothermal liquefaction?

Posted on June 8, 2022 by DrRossH in Plastic Recycling


hydrothermal liquefaction

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: Geelong-Altona 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 recycling, where plastic needs to be sorted by type, advanced recycling can process mixed plastics, including multilayer packaging.

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 oil, making it easier to upgrade in a conventional refinery.