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Published on July 28th, 2009 | by Tina Casey


Biodiesel Yields Hidden Treasure in Waste Glycerin

July 28th, 2009 by  

One gallon of crude glycerin is produced for every 9 gallons of biodiesel, making the disposal of waste glycerin a growing environmental issue.The world is awash in a glut of crude glycerin, a major byproduct of biodiesel manufacture. The big question is what to do with it all.  In the U.S. alone, about 340,000 tons of unrefined glycerin came into the market in 2007.  Over half of that came from biodiesel, and those numbers are bound to go up as the market for this alternative fuel grows.  Glycerin is used to manufacture soaps, cosmetics, pharmaceuticals, and many other products, but crude glycerin is an impure form that is unsuitable for many of these purposes.  Right now most crude glycerin is simply incinerated, a practice which undermines biodiesel’s potential as a truly sustainable fuel.  But all that is about to change.


Glycerin: The Little Molecule that Could

Pure glycerin, also called glycerol or glycerine, is colorless,  odorless and nontoxic in its refined state.  It is composed of three carbon, eight hydrogen, and three oxygen atoms.  As reported last year in The Guardian by writer Michael Pollitt, the hydrogen-rich molecule is a a regular mother lode for researchers in the alternative energy and fuel cell fields.  At the University of Leeds, a team lead by Dr. Valerie Dupont has separated the three atoms with steam and absorbent filters.  The process yields a rich hydrogen gas that could be used both for large power generating purposes and for portable fuel cells – a development that is sure to catch the eye of DARPA and other defense agencies.  The team has won the team a series of grants from the U.K.’s Engineering and Physical Sciences Research Council to commercialize the process, called Unmixed and Sorption-Enhanced Steam Reforming.

Crude Glycerin: But Wait, There’s More

The Leeds research is just the tip of the iceberg.  At Virginia Tech, assistant professor Zhiyou Wen is using crude glycerin to grow microalgae that produce omega-3 fatty acids, an important nutrient.  As a side bonus, the spent algae could be used as animal feed.  Researchers at Truman State University in Missouri are pursuing that angle with glycerin-based cattle feed.  Elsewhere in the state, Missouri University has developed nontoxic antifreeze from crude glycerin.  Other researchers are focusing on the potential for producing ethanol and methanol from crude glycerin, including a new low-impact methanol production process that yields methanol without releasing hydrocarbon gasses as a byproduct.  Crude glycerin may be a waste product now, but in terms of a sustainable future it may well become gold mine.

Image: celine nadeau on flickr.com. 


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About the Author

specializes in military and corporate sustainability, advanced technology, emerging materials, biofuels, and water and wastewater issues. Tina’s articles are reposted frequently on Reuters, Scientific American, and many other sites. Views expressed are her own. Follow her on Twitter @TinaMCasey and Google+.

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