Greenback: Valorising flexible plastic through chemical recycling

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Microwave Pyrolysis: Valorising Flexible Plastics Through Chemical Recycling

Since June 2023, a state-of-the-art plant in Cuautla, Mexico, has been steadily converting flexible plastics into pyrolytic oil, an important raw material which can be used to produce food-grade plastic packaging.

By collecting and processing these film and flexibles, and reintegrating them into the economy for reuse, UK-based Greenback Recycling Technologies, partnering with Nestlé Mexico and the Alliance, aim to valorise this often neglected, low-value material.

The plant valorises waste using microwave-induced pyrolysis – a chemical recycling process developed by Enval, an offshoot from the University of Cambridge, specifically to recover recycled materials from multilayered flexible packaging and plastic films, which are typically challenging to recycle through traditional mechanical means.

Using microwave energy, plastics are broken down into solid, liquid, and gaseous components. The gas is channelled back into the system for power generation, and the oil is then sold to petrochemical companies that use it to produce plastic containing recycled content. This process also allows for the recycling of another valuable material, namely aluminium, which is commonly found in these types of packaging.

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Greenback also brings much-needed transparency to waste processing through its proprietary eco₂Veritas™ Circularity Platform, which can demonstrate that the materials being reintegrated into the economy originated from post-consumer waste. Using the Internet of Things (IoT) and blockchain technologies, the pathway of the plastic waste along the value chain can be traced, providing evidence of the source. Certifications are issued for the neutralised waste.

Rather than establishing a centralised hub for waste aggregation and pyrolysis oil production, Greenback adopted a modular, decentralised approach by bringing pyrolysis oil production directly to the waste supply. This recycling model is co-located to an existing Materials Recovery Facility (MRF) adjacent to the La Perserverancia landfill, where sorting takes place – to ensure a continuous flow of feedstock. It also allows it to quickly adapt to the available waste stream. The plant is designed to be modular and can be scaled when more capacity is needed. Each module has the capacity to process the approximate amount of flexible plastic packaging waste generated by 260,000 people a year. The project envisions two modules, each with the capacity to process 3,000 tonnes of waste per annum. The second module – supported by the Alliance – is being commissionedand scheduled to come online in early 2025.

Greenback not only provides a replicable, scalable and cost-effective way to glean pyrolysis oil and other recyclables from low-value plastic, but also addresses a critical shortage of recycled materials amidst growing demand by consumer packaged goods companies (CPGs). While many are committed to using higher percentages of recycled plastic in their packaging, supply – particularly for food packaging – remains low.

Through its voluntary extended producer responsibility programme, CPGs can contract the services of Greenback, which ties up with existing waste collectors and sorters to collect, sort and deliver this previously “worthless” plastic waste to the recycling plant.

Ultimately, this gives plastic packaging that may not currently be recycled a route back into the plastics value chain, further advancing the circular transition. Greenback intends to quickly replicate with additional lines in Cuautla, or other locations in Mexico, and in many countries around the world.