Environmental Health & Safety

Deflect a double whammy

Consider new options for tackling economic and environmental concerns.

By Mark Rosenzweig, Editor in Chief

Some in the chemical industry probably dismiss talk about the potential widespread use of renewable resources as feedstocks as wishful thinking. Cynics may write the hoopla off as a ploy by the agricultural lobby or other vested interests to wrangle more money out of the government. Skeptics may argue that biofeedstocks may make sense in very specific, limited circumstances but won’t provide a practical platform for many chemicals.

I strongly disagree with the naysayers. As we’ve regularly reported (see, for instance, www.ChemicalProcessing.com/articles/2007/177.html), significant progress in commercializing renewable-resource-based routes is occurring. Major players like Dow and Dupont already have processes relying on such feedstocks.

The rising prices of crude oil and natural gas certainly are boosting the relative economics of using biofeedstocks — and thus companies’ interest. After all, no chemical producer can afford to ignore prospective bottom-line benefits.

Some firms also value the sustainability of such feedstocks and their potential for cutting harmful emissions, as I’ve already noted (www.ChemicalProcessing.com/articles/2007/178.html).

So, it’s no surprise that acceptance of biofeedstocks is accelerating. But the question remains about just how extensive a role they can play. Analyses done at the University of Utrecht in Holland provide some insights. Barbara G. Hermann of the school’s Department of Science, Technology and Society looked at 15 chemicals that potentially could be made via fermentation — chosen with the help of a panel of experts from companies such as BP, DSM, Dupont and Shell — and that could support annual production of at least 200,000 metric tons in Western Europe.

She developed a generic approach for evaluating the chemicals, which range from caprolactam to ethylene to succinic acid, on a common basis, comparing fermentation-based and conventional production (see p. TK). For the bio-based routes, she did analyses for current and future technology (which she assumed would involve continuous fermentation and achieve yields of 90 mol.% of their theoretical maximum, thanks to better genetically engineered microorganisms).

Her first study, published last year in Applied Biochemistry and Biotechnology, focused solely on economics. She developed profited production costs (which are akin to market prices). These included operating expenses as well as capital charges reflecting the investment required for a new 100,000-m.t./yr. plant in Western Europe; sensitivity analyses addressed variations in the prices of sugar and oil, as well as plant size. With current prices, bio-based routes using today’s technology provide better economics for many of these bulk chemicals, she concludes. As a feedstock, sugar cane fares best, followed by lignocellulosics and then corn starch.

Hermann then evaluated the potential savings in non-renewable-energy use and greenhouse gas emissions for the same 15 chemicals over their entire life cycle, and has just reported her findings in Environmental Science & Technology. Almost all bio-based routes using current technology offer clear benefits on both counts and future technology may allow cuts in greenhouse gas emissions to exceed 100% in some cases, when energy credits are factored in, she notes.

So, biofeedstocks may offer chemical makers broad opportunities to address both economic and environmental pressures.

Mark Rosenzweig
Editor in Chief

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