We can’t do without plastic, but it must be produced and managed in a sustainable way. Champions from the bioplastics and recycling industries are pushing their own solution as the best answer to the problems of waste plastic, in a direct challenge to the conventional petrochemicals industry. But the big polymer producers are adapting and taking on the two new contenders at the same time.
The naphtha cracker, the backbone of the petrochemicals industry, is being repurposed to serve both the bio and circular economies. Established producers are increasingly feeding liquids derived from biomass or waste plastic, with conventional fossil raw materials, to their crackers. New announcements in 2019 confirm that more polymer manufacturers are following this route.
Biovyn is the latest new product from Inovyn, to join Circulen from LyondellBasell, TRUCIRCLE™ from SABIC and Infinia from BP. These announcements cover the majority of polymers in general use; PVC, PE (polyethylene), PP (polypropylene) and PET. Most rely on allocating the bio or recycled carbon containing molecules coming out of the cracker to a particular customer. The quantities are usually quite small, so in the case of bio-products, the resulting polymers have no measureable biogenic carbon content, as it has been physically distributed over many different products. Companies have come up with different names to describe these products such as ‘bio-attributed’ and ‘biomass balanced’. The co-processing of waste plastic is known as chemical or molecular recycling. The important question for the industry is however, will it be able to go further and provide a continuous supply of high bio or recycled content plastics?
There are obstacles on the path to the renaissance of the cracker. Mixed waste plastic contains impurities and contaminants, which must be removed in a separate process, before the material is suitable for feeding to a cracker at high concentrations. This will be expensive. On the plus side, the material will be suitable for food contact, and there is every indication that the authorities will accept it as recycled content. So, if food companies are willing to pay the price, the scale-up can progress. Plastic waste sorted by type can continue to bypass the cracker and be mechanically recycled and blended for lower grade applications.
Scaling up bioplastic production will require large quantities of bionaphtha or heavier drop-in bio-liquids. These come from vegetable oils via an HVO (hydrogenated vegetable oil) process, developed for the biofuels industry. Vegetable oils are relatively expensive, and palm oil, the cheapest, is tainted by association with deforestation. Furthermore, HVO production currently depends on biofuels incentives to survive. HVO capacity could be switched from biofuels to bioplastics, but again it will depend on the customer’s willingness to pay.
The bioplastics industry can of course continue to develop its existing standalone facilities making bioplastics from sugar and starch. A number of these products are biodegradable which makes them eminently suitable for certain niche applications, for instance food waste that remains in the packaging. However, incompatibility with recycling infrastructure and reliance on composting as an end-of-life solution are barriers to their scale-up.
So it is safe to say that a vision is emerging of the plastic of the future. Mechanical recyclate, blended with some virgin plastic, will be used for low-grade applications. High technical specification and food grade material will have as high a bio or recycled (or both) content as the market can support or authorities demand. The expensive bio and recycled content will be allocated to applications where regulation and consumer pressure require it. Some disagree with this vision, arguing for a future without new plastic, but the industry is cracking on regardless.
Published: 15 December 19
