Chemical makers tackle biodiesel byproduct glut

June 6, 2007
A rash of plans to produce glycol from glycerin is good news for green chemistry.

Compared with the bioethanol market, U.S. biodiesel production hasn’t geared up to the levels seen elsewhere in the world, particularly in Europe. While Europe as a whole only accounted for around 6% of global bioethanol production in 2005, it was then producing some 850 million gallons a year of biodiesel when U.S. production was only just beginning to takeoff, having risen from 25 mgpy in 2004 to 75 mgpy in 2005. Europe’s bioenergy mix is still skewed more toward diesel than ethanol, but some recent announcements by U.S. chemical companies suggest that biodiesel production could soon receive a boost.

In our January feature on “green chemistry”, we pointed out that the economics of biodiesel production were strongly linked to the market for glycerin (glycerol), a byproduct of the transesterification of vegetable oils into the methyl esters that make up biodiesel. At the moment, demand for glycerin — mainly from the pharmaceutical and cosmetics industries — is running well behind forecasted supply from a burgeoning biodiesel industry, which urgently needs more outlets for its glycerin surplus. One new industry/academic consortium is specifically aiming to develop technology to transform the material into high value chemicals.

The prospects for greater use as a raw material are already looking more promising, following a surge in plans to produce propylene glycol (PG) from glycerin, in place of the traditional propylene oxide route. Global production of PG totals more than 1.4-million metric tons/y and is growing at between 3% and 7%, according to Ashland, Covington, Ky., a specialty chemical company. Providing a less toxic alternative to ethylene glycol for use as an antifreeze, PG also is a common ingredient in a wide variety of resins, lubricants, cosmetics, paints and other everyday products. Ashland recently announced a 50-50 joint venture with the food and agricultural giant Cargill, Minneapolis, Minn., to develop and produce bio-based chemicals. Using both proprietary and licensed technology, the new company’s first product will be PG, starting with a 65,000-m.t./y plant in Europe.

“Cargill’s expertise in converting vegetable-based oils is world-class, its global reach is unmatched and its glycerin supply chain expertise will promote a quick market rollout,” says Dave Jones, Ashland’s director of bioproducts. “All this will provide a competitive advantage over other manufacturers attempting to produce any product derived from vegetable oils.” A competitive advantage that’s likely to be tested fairly soon in the wake of similar announcements from chemical giants Dow, Midland, Mich., and Huntsman, Salt Lake City, Utah.

Dow, in March, introduced “Propylene Glycol Renewable (PGR)” to be made from biodiesel-generated glycerin. Dow is conducting PGR trials with customers and anticipates having “limited commercial quantities available in mid-2007.” The company has entrusted PGR production to its Dow Haltermann Custom Processing business unit, which is conducting pilot trials with eventual full-scale production at its Houston facility.

Texas also is the location for Huntsman’s first foray into bio-based PG, initially at its process development facility in Conroe, according to an April announcement. This plant can turn out the glycerin-based product in “intermediate scale” quantities, with the first supply due to be commercially available by 2008. Further scale-up and transfer of the process to Huntsman’s larger scale plants can then be expected. The company currently operates a 65,000-m.t./y conventional propylene glycol plant at Port Neches, Texas.

Dow, meanwhile, claims to be the world’s largest producer and marketer of PG — which it says can now be offered in two grades, conventional industrial grade (PGI) and the new PGR. “PGR pricing is independent of the volatility associated with hydrocarbon and energy costs,” says Mady Bricco, Dow’s global product director, propylene oxide/propylene glycol, while acknowledging the potential for future variability in seed oil and glycerin costs — a variability from which Dow hopes to be sheltered by growing both product lines in tandem. “From an economic standpoint,” explains Bricco, “the dual offering gives Dow and its customers a distinct competitive advantage.”

Whoever comes out on top in this new PG market, there are already two winners — the biodiesel industry, with new outlets for its byproduct, and the chemical industry, with further evidence of the benefits in “going green.”

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