Viva pretty polymers

C&I Issue 18, 2007

In brief

  • Production of ethanol from sugar cane in Brazil is three to five times more efficient than from corn in the US
  • Polyethylene (PE) derived from ethanol is identical to that produced from fossil fuels
  • Brazil is set to double the world’s current biopolymer capacity

In the past few months, two major polyolefins producers, US-based Dow Chemical and Brazil’s Braskem, have separately announced plans to build large-scale polyethylene (PE) plants based on bioethanol. Both companies will locate their plants in Brazil, a world leader in bioethanol production and a key polymers market in Latin America (C&I 2007, 14, 11).
Brazil, which produces ethanol from sugar cane, is the world’s most competitive ethanol producer, says Tony Kingsbury, global plastics sustainability leader at Dow. In the US, where bioethanol production is based on corn, it would take three to five times more land to grow enough corn to produce the same amount of ethanol that you would produce from sugar cane in Brazil, he says.

Dow and Braskem say their new processes will produce significantly less CO2 than traditional PE manufacturing processes based on natural gas or naphtha. Dow estimates that the carbon footprint of its process will be about 15% of that of traditional PE production. The calculation, Kingsbury notes, takes into account the carbon footprint of the sugar cane operations, including transport of the product and use of fertilisers.

While the carbon in traditional PE is derived from oil or natural gas, the carbon for this PE comes from the CO2 that the sugar cane captures from the air, says Kingsbury. ‘This polymer has a wonderful carbon footprint because, essentially, it comes from air, water and sun.’

The high price of oil makes the ethanol route particularly economical, says Manoel Carnaúba Cortez, Braskem’s vice president for basic feedstocks. ‘An oil price of over $50/bbl makes our process very competitive.’

  A thing of beauty
The beauty of PE derived from ethanol, remarks Kingsbury, is that it is identical to PE derived from fossil fuels. Customers know exactly what they are getting and can process the polymer using their existing equipment without modification. ‘This is a huge advantage compared with some other bio-based polymers that are “new to the world” polymers, which means customers are less familiar with the properties and the processing capabilities,’ he says. ‘This is a drop-in replacement.’

Dow’s plant, which will produce350 000 t/year of Dowlex linear low density PE (lldPE), will double the world’s current biopolymers capacity, estimated at 300 000-400 000 t/year, says Kingsbury. This will effectively dwarf the output from other existing biopolymers producers such as Natureworks, a Cargill subsidiary, which has a 140 000 t/year corn-based polylactic acid (PLA) plant in Nebraska, US.

Crucially, the ethanol route will allow Dow to build a PE position in Brazil, which has limited supplies of fossil fuel-based petrochemicals feedstocks and where competition for ethylene among local resin producers is already fierce. Although Dow already has various manufacturing sites in Brazil, it has no PE production and has to supply the Brazilian market from its Bahia Blanca plant in Argentina and from its US facilities.

The large amount of land available for growing sugar cane and the high efficiency of the sugar cane to ethanol process make Brazil the best place to conduct this project, says Kingsbury. ‘It’s a growing market. They are the world leaders in ethanol production, they have very high efficiencies for producing low cost ethanol, and they do not have a lot of oil and natural gas,’ he adds.

Dow will implement its project through a joint venture with Brazilian ethanol producer Crystalsev. The joint venture will enable Dow to ‘become more Brazilian, and not be seen as an outsider,’ observes Jorge Bühler-Vidal of US-based Polyolefins Consulting. ‘Through this joint venture they get clean, uncomplicated access to raw materials, in addition to the differentiation they obtain by being green.’

Premium product

Braskem calculates that the environmental benefits and lower carbon footprint of ethanol-derived PE will allow it to charge an average premium for the product of 15-20%. Braskem’s customers, the plastics processors, are reporting a rising demand for packaging materials based on renewable resources and with a low carbon footprint, says Carnaúba.

Braskem’s PE project provides the group with an opportunity to become a leader in environmentally-friendly plastics, says Carnaúba. As a Brazilian company, with good relationships with the sugar cane/ethanol companies, Braskem has the advantage over other companies entering the ethanol-to-polymers market, he says.

Demand for green PE is strong in Asia, particularly Japan, as well as in Europe, particularly the UK, Germany and Scandinavia, according to market research conducted by the Brazilian group. There is some interest from the US, Carnaúba says, although not as much as in some Asian and European countries. The research demonstrates substantial demand for the product in applications such as food packaging, packaging for personal care and domestic cleaning products and supermarket bags, he adds.

But will Braskem achieve such a large premium? asks Bühler. And how will the plastics transformers demonstrate the product’s advantages to end users? He notes that retailers that claim to be environmentally responsible, such as Whole Foods in the US, would be most likely to pay a premium for packaging made from green PE.

For now, Dow is focusing is on building its presence in Brazil rather than seeking a premium for the product. ‘Our business model is not predicated upon us being able to get a significant premium for this,’ says Kingsbury, noting that the market will end up determining the price. ‘Since it’s  a known polymer, we don’t expect that it will vary that much from traditional Dowlex PE prices.’

While the US group has developed its project for the Brazilian market, the positive global response means ‘there’s clearly an opportunity that we may end up selling some of this outside Brazil’, Kingsbury adds.

In both projects, the companies will convert ethanol to polymer-grade ethylene and use standard polymerisation processes for conversion to PE.
The Dow/Crystalsev project involves an integrated ethanol-to-ethylene-to-PE facility, to be located in the central-south region of Brazil. The 350 000 t/year project will be the world’s first commercial-scale sugar cane-to-PE plant when it comes onstream in 2011, says Kingsbury. The cane will come from new fields and Dow stresses that the areas being considered as potential sites for the project are currently being used for low-density cattle grazing and are not near any rain forests.

Braskem’s project is scheduled to start up ahead of the Dow facility but will be smaller-scale. Due onstream by the end of 2009, it will have a capacity of between 120 000 and 200 000 t/year of PE, requiring an investment cost of between $70m and $120m. Carnaúba says the group plans to raise the capacity to 300 000 in 2014.

Braskem will source its ethanol raw material from various suppliers, located in the southeast, Brazil’s main ethanol-producing region, as well as the northeast. The group will seek long-term supply agreements with a variety of suppliers, Carnaúba says, and will also have the option to purchase ethanol from its controlling shareholder Odebrecht.
Braskem will become a consumer of ethanol this month when its Copesul business starts producing ethyl tertiary butyl ether (ETBE) in Triunfo. The company will increase its ethanol purchases in July next year when it commences ETBE production in Camaçari in the northeastern state of Bahia.

Dow already had an in-house process for converting ethanol to polymer-grade ethylene, used by Dow subsidiary Union Carbide in Brazil in the 1970s and 1980s. Braskem recently developed its process.

Braskem’s $5m R&D project, conducted in Triunfo in southern Brazil, included construction of a 10 kg/hour pilot plant for producing polymer-grade ethylene from ethanol. The breakthrough occurred in March, says Carnaúba, when the pilot plant produced its first polymer grade ethylene. ‘We are very confident in our technology. And as we will be the first to produce this product in the market, I think our followers will have difficulties competing with us.’

Braskem, which has various PE production sites across Brazil, including Triunfo, has produced high density and low density PE from ethylene from the pilot plant. It also plans to produce polypropylene (PP) from ethanol, either using an existing route such as ABB Lummus’ propylene

metathesis technology, or by developing its own technology, reveals Carnaúba.

Steady advances in production technology will help drive up the production of polymers and other chemical based on renewable resources. ‘There’s a world of opportunity ahead of us in terms of renewable feedstocks and we’re going to learn a lot more in the coming years,’ says Kingsbury. ‘Lots of companies are talking about sustainability. This is showing that we are putting our money where our mouth is.’

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