Chemical recycling has the potential to provide a solution for mixed plastics waste - and to help meet the demand for high-quality recycled plastics. It is an attractive proposition, and one that has led to a surprisingly high number of projects and technologies, most of which are still at the experimental phase or have not yet progressed beyond pilot scale. The technology is still just emerging but the race is on, to develop a recycling process that can be ‘scaled up to chemical industry volumes, is flexible enough to use most plastic wastes as feedstocks, has an attractive LCA, can economically enable the purchase of waste plastic feedstock, and is simple and cost effective’, said David Sudolsky, president and CEO of Anellotech, a sustainable technology company founded in 2008 in New York.
Anellotech first developed and patented its Bio-TCat technology, a thermal catalytic process for converting biomass into bio-based BTX, or benzene, toluene and xylene - all chemically identical to their petroleum-based counterparts. That process is now ready for commercialisation.
Meanwhile, the company also decided to expand its development programme, and in 2019 announced it was working on Plas-TCat, a new process technology which was aimed at converting a wide range of plastic waste directly into chemicals – which could then be used to make new, virgin plastics. The process, said Sudolsky, is the game-changer the industry is looking for, able to meet the criteria he mentioned above.
Plas-TCat technology, he explained, can transform plastic waste such as composite films, mixed plastics and plastics with biomass – such as paper labels – directly into valuable chemicals. “It can handle oxygenated polymers, an important advantage over pyrolysis processes that produce complex oil mixtures which require upgrading and additional conversion in steam crackers,” he said.
The Plas-TCat process is anticipated to have significantly higher yields of olefins (<C5 olefins) and BTX over today’s conventional pyrolysis plastic recycling technologies, which would be coupled with secondary processing in an ethylene pyrolysis furnace. It therefore offers a new, direct route to olefins and aromatics from low value plastic waste feedstock. Preliminary LCA assessment indicates a potential to reduce CO2 emissions up to 50% versus monomers from steam crackers.
While the preferred feedstocks for Plas-TCat are polyolefins, the process can also profitably process nylon, PET, polystyrene and other plastics that are widely used today.
The scalability of the process means that commercial plants should be able to exceed 200,000 metric tons/year of olefins and/or BTX production from a single reactor system processing majority polyolefin plastic waste.
Plas-TCat main products include aromatics (benzene, toluene, xylenes), olefins (ethylene, propylene) and low molecular weight paraffins (ethane, propane).
In June 2020, Anellotech announced that R Plus Japan Ltd., a newly formed joint venture company, is providing financial and strategic support for the development of Plas-TCat technology for recycling used plastics. RPJ was established by 12 cross-industry partners within the Japanese plastics supply chain. Since formation, RPJ now has grown to over 38 member companies, and has a goal to have a Plas-TCat commercial unit operating in Japan in 2027.