14 Februar 2012

Does Bio-Polypropylene Make Economic Sense?

Quantitative comparison of the cost of producing bio-propylene versus conventional petrochemical propylene

With its successful launch of bio-polyethylene, Braskem is now also turning its attention to bio-based polypropylene. The company recently announced that it will produce at least 30,000 metric tonnes/year of bio-based propylene from ethanol by the end of 2013. The propylene will be used to make polypropylene and will have the same properties as conventional hydrocarbon-derived propylene. Braskem acquired the PP business of Sunoco in 2010 and of Dow in 2011, so the motivation to expand its portfolio to include bio-based PP is understandable.

But the big question is if the bio-based PP will be cost-competitive with conventional petro-derived PP. This question will be tackled by Nexant consultant Ronald Cascone in a presentation to be delivered at the BioPlastek 2012 Forum on March 28-30 in Arlington, Virginia, USA.

As with any cost analysis, the answer to the above comparison is “it depends.” Among the variables that must be considered are the routes to renewable propylene, economies of scale, feedstock costs and type, geographic access of feedstock to biorefineries and, of course, petrochemical propylene economics. The assumption is that since the bio-based propylene monomer will have the same properties as the petro-derived monomer, the corresponding PP resins will perform in similar fashion.

In a just-published multiclient study, Nexant identifies several renewable propylene routes with the possible potential to compete with conventional fossil fuel derived production routes. Cascone believes the two most economically viable of these pathways now available are:

Using ethanol-derived ethylene to make butylene and, next through a commercial process known as metathesis, react ethylene with butylene to make propylene.

Gasifying biomass to produce syngas for methanol production; methanol is converted to mixed olefins (MTO) or, alternatively, mostly to propylene (MTP).

Braskem’s relatively small propylene plant will utilize the readily available dimerization and metathesis technologies, according to Nexant. The consultancy also believes that this approach may not be on a par economically with petro-derived propylene mostly because of small plant size. Although the gasification approach to produce syngas is economical, it is less attractive because it is capital intensive. Longer term, the direct production of propylene in a sugar fermentation process using price-advantaged (e.g. cellulose) feedstocks would likely be substantially more economical than the petrochemical routes, in Nexant’s view. Novozyme is collaborating with Braskem towards commercializing this pathway.

To hear details of Nexant’s quantitative comparison of the cost of producing bio-propylene versus conventional petrochemical propylene, plan on attending the BioPlastek 2012 Forum. This talk will be part of a unique session — not found at competitive conferences — which compares the economics of drop-in biopolymers and their petro-derived counterparts as well as presenting comparative feedstock economics.

Source: Bioplastek, 2012-02-14.

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