Attempts to improve polystyrene’s public image drive bio-aromatics demand
By Callum Colford, Simon Price, Callum Sinclair
The aromatics sector has also seen increasing interest in bio-polymers in recent years, with end-products including polystyrene and acrylonitrile-butadiene-styrene driving demand for bio-based styrene. The bio-based styrene route has been increasingly explored with multiple major producers offering material produced via the mass-balance approach.
Companies such as BASF produce bio-based styrene via the mass-balance approach and have entered a partnership with companies including Trinseo, which then use the bio-based styrene to produce a bio-based polystyrene and synthetic rubber products.
In addition, since 2020 Trinseo has been producing its own bio-based styrene at its ethylbenzene plant in Terneuzen. The process replaces the fossil-based benzene used in the manufacture of styrene with an oil-like substance made from waste produced during the wood-pulp manufacturing process.
The manufacture of styrene allows a mixture of bio-based material to be used with Trinseo noting its first bio-based styrene produced had 75% bio-content, from 100% bio-benzene blended with ”traditional” fossil-based ethylene.
INEOS Styrolution sources material from second-generation feedstocks and offers bio-attributed styrene-butadiene copolymer block applications where 100% of fossil material has been replaced by bio-attributed styrene alongside other mass-balanced offerings.
There is growing momentum coming from the polystyrene sector to shift to bio-based material, with the sector one of the more vocal end-applications in moving towards second-generation feedstocks in order to burnish green credentials due to the perception that it lags in recycling applications.
“The problem yesterday was that there was no technology for high-quality PS recycling — let’s say food quality PS recyclates. To be used in [food] packaging you need to have this food-approved quality, and without being able to provide this, you close the door of the major retailers to PS demand,” one producer said, explaining why the PS sector has had particular interest in bio-based styrene.
However, sources note that bio-based production has increasingly taken a back seat to recycling despite the ability of the sustainable methods to work hand in hand.
“Bio is a complementary element to recycling as recycling is a yield and you lose material during the recycling process. You have to compensate with virgin material, and if you don’t want fossil-based virgin material then you will have to have bio-sourced virgin material,” said Trinseo’s Dr. Julien Renvoise.
The use of bio-based benzene extends beyond styrene production. Covestro has produced aniline which is then used to produce diphenylmethane diisocyanate (MDI) — used in the manufacture of polyurethane foams — from a bio-based sustainable benzene produced by TotalEnergies in northern France.
Benzene producers have told Platts they expect a rapid expansion in demand for bio-based products in the coming years and are looking at how to increase the bio-content of material to work alongside recycling in a circular approach.
Although ETBE is the most widespread bio alternative to MTBE, it is not the only option. Bio-MTBE has also been gaining traction as EU policy rewards advanced biofuels. Existing infrastructure can be used to produce bio-MTBE, with the feedstock bio-methanol used instead of conventional methanol.
"Everyone who can produce MTBE can produce bio-MTBE; they are the same molecule," a trader said. "The approach now is to use mass-balance."
Saudi producer SABIC produces bio-MTBE at its site in Geleen in the Netherlands from second-generation bio-methanol derived from sewage, manure and other organic waste.
Other companies developing bio-MTBE production include LyondellBasell, with Evonik having produced bio-MTBE at its Marl site since 2012.
Bio-MTBE product specifications are the same as MTBE, providing a direct replacement for the ether. Bio-MTBE is produced from bio-methanol which is classified for advanced biofuel production, making bio-MTBE eligible for double counting under RED II Annex IX.
Double counting encourages the use of second-generation biofuels by crediting twice the number of bio-tickets (or HBEs). These bio-tickets can be traded with biofuel producers potentially selling its ticket to non-obligated industries such as aviation and shipping. Nevertheless, the high production cost is so far limiting market adoption, according to sources.
