Major manufacturers such as DuPont and Dow are joining a growing roster of firms relying on biofeedstocks. Economics as well as increasing corporate emphasis on sustainability and environmentally friendly products are spur-ring the use of such materials to make chemicals and fuels.
Concurrently the menu of biofeedstocks continues to expand. It now includes virgin materials such as corn, sugar cane, oils from cotton seeds and soybeans, grass and hardwoods, as well as biofuels byproducts such as glycerin, and even animal-derived materials like pork lard and chicken fat.
Heres a look at some biofeedstock-based plants now being commer-cialized or on the drawing boards, plus some promising bioresearch projects.
DuPont, Wilmington, Del., has joined with Tate & Lyle, London, U.K., to commercially manufacture 1,3 propanediol from corn via fermentation. On June 8, its DuPont Tate & Lyle Bio Products joint venture officially opened the worlds first full-scale plant, a $100-million facility at Loudon, Tenn, to make Bio-PDO (Figure 1).
Figure 1. Plant at Loudon, Tenn., makes two product lines based on corn fermentation.
We have two generic products, explains the joint ventures presi-dent Steve Mirshak; their different characteristics suit them for specific ap-plications (Figure 2). Zemea propanediol finds use in personal-care and liq-uid-detergent consumer goods. Susterra propanediol finds use in industrial applications such as de-icing fluids, antifreeze and heat-transfer fluids.
Figure 2. Corn-based propanediol goes into products ranging from cosmetics to industrial heat-transfer fluids.
To get the right bug to transform corns sugar into Bio-PD, DuPont worked with Genencor, a Rochester, N.Y.-based division of Danisco A/S, Copenhagen. Then, DuPont allied itself with Tate & Lyle. They began de-velopment in 2000 at a pilot plant at Tate & Lyles research center and North American headquarters in Decatur, Ill., and in May 2004, created the joint venture. The 100-million-lb/yr plant went onstream in November 2006. The Loudon facility features nine-story fermentation vessels, the worlds largest, says Mirshak, who expects output to reach full capacity by 2009.
The plant also boasts a positive environmental impact. We use 40% less energy to produce Bio-PD than a petroleum-based [glycol] product, he says. We recently revised our lifecycle estimates and found that cradle-to-gate, from the cornfield to the exit of our plant, reduces greenhouse-gases emissions by 56%.
The development is already garnering accolades. The research teams from DuPont, Tate & Lyle and Genencor received a 2007 Heroes of Chem-istry Award from the American Chemical Society.
Instead of corn, Dow Chemical, Midland, Mich., is relying on sugar cane as a feedstock. This summer Dow and Crystalsev, a Brazilian sugar-cane grower and ethanol producer, set up a 50/50 joint venture to build the first world-scale integrated facility to convert cane sugar into polyethylene.
The joint ventures product will have the same functionality, look and feel of Dowlex resins manufactured at other Dow facilities, notes Jim Fitterling, president of Dow Basic Plastics. The Brazilian site will include 120,000 hectares, or approximately 250,000 acres, of sugar-cane production. Well crush about 8 million tons of sugar to produce 700,000 liters [184,000 gallons] of ethanol. The polyethylene facility will consume about 350,000 liters or 92,200 gallons, he adds.
The still-unnamed joint venture already has already started a year long study that will get into the engineering design, location, infrastructure needs, supply-chain logistics, energy and economics. Fitterling predicts ethanol production from the plants first unit in 2009 and its second in 2010. Full productions expected in 2011, when we can go ethanol-to-polyethylene.
The prime motivation for Dow, which has an established position in the Brazilian polyethylene market, is to insulate itself from high and volatile costs of conventional feedstock. A positive impact on climate change wasnt an initial driver, but as we developed the project, interesting things arose regarding sustainability and renewable resources, Fitterling adds, noting the project will have about one-seventh of the CO2 footprint of traditional poly-ethylene production.
Another project benefit will come through co-generation of energy by combustion of bagasse or residue cane fiber. Sugar cane produces six-to-eight times the energy required for its conversion to ethanol, Fitterling ex-plains. Beyond using recovered energy in ethylene/polyethylene production, the joint venture will sell some to the electrical grid.
Corn-to-ethanol technology, which is popular in North America, was a nonstarter for this project. One limitation was its slower reaction kinetics, Fitterling notes. That makes it very uncompetitive compared to sugar cane in Brazil.
Meanwhile, in the U.S., Dow is making headway in natural-oil polyols (NOP), which it began investigating in the late 1990s. We moved ahead in earnest after the  purchase of Union Carbide, recalls Erin ODriscoll, Dow Polyurethanes business development manager.
Using Dow-developed process equipment and Carbide-based hydro-formulation technology, Dow ran a full-scale production campaign for soy-based polyol at a contract manufacturer in 2005, she notes, making hundreds of thousands of pounds of NOP for commercial trials by end-users (Figure 3).