Neste and IKEA recently announced a partnership to ‘deliver renewable, bio-based plastics’, which must be taken very seriously, as they are world leaders in biofuels and consumer goods respectively. They believe that European consumers want to buy goods made from bioplastic.
However, missing from the announcement was any mention of how the bioplastics will be produced, possibly because this is the most difficult and expensive part. A few years ago, an announcement by Sabic that it was making bioplastic in the Netherlands, caused a heated industry debate when it emerged that the bioplastic did not contain the biomass derived carbon people assumed it did.
The Neste/IKEA announcement specified that the bioplastic will be compatible with existing recycling streams so that implies they are looking for drop-in products to replace oil derived polyethylene (PE) and polypropylene (PP).
Neste’s source of biobased feedstocks are by-products from the production of biodiesel from waste oils and fats at their refineries in Finland and elsewhere. These can be fed to an existing ‘cracker’ to produce bioethylene or biopropylene, which can then be polymerised to make drop in bioPE and bioPP. However, crackers and polymerisation reactors are built to a huge scale and so the bio-feedstock is diluted with fossil oil derived feedstock which is processed at the same time. Further dilution occurs in the polymerisation reactor so any one batch of PE or PP has a very low bio-based content.
Sabic got around this problem by allocating the bio-based content to particular batches on a ‘mass balance’ approach which was overseen by auditors. Industry experts and consumer brands didn’t readily accept this approach. Measurements, based on the carbon 14 technique used in carbon dating, can distinguish between fossil and bio –carbon; so the ‘mass-balance’ bio PE would not contain much, if any detectable carbon from the original biomass.
This ‘mass balance’ approach is in contrast to that pioneered by Braskem in Brazil. They use bioethanol from sugarcane to make bioethylene by dehydration. The bioethylene is polymerised in a dedicated facility to make bioPE, whose high biocontent claims are genuine and can be justified by measurements. This technology has not yet been replicated elsewhere.
So what is needed to make real, high bio-content drop-in bioplastics in Europe? As well as feedstock at the right price, investment is needed in new or upgraded plant. This could be new build bioethanol dehydration or retrofit to an existing cracker to enable processing of bio feedstock to produce high bio-content PE. There was no mention in the Neste/Ikea announcement of how that will happen or who will do it.
Published: 20 September 16
