Forget about algae? Wisconsin researchers turn raw biomass into biofuels via two step chemistry

February 11 2009 / by Garry Golden
Category: Energy   Year: 2013   Rating: 4 Hot

ChemistFlickrBioenergy visionaries with algae and bacteria aren't the only players in town trying to corner the market on the 'future of biofuels'.  We cannot forget the Chemists.

Biofuels are expanding along two paths- one is based on chemical engineering, the other on biological processes.

Chemistry vs Biology
We can create biofuels by applying chemical engineering processes (e.g. ethanol via fermentation, or biodiesel via transesterfication) with high reliability and scale, but usually at a high cost.  

Or we can let Mother Nature do the work. Biology taps the power of algae and bacteria that contain special enzymes that reorganize molecules into a format that can be used to make biofuels, or converted into electricity via a fuel cell.

Biology could offer lower cost and turn carbon emissions into a feedstock, but first we must overcome challenges of scaling up volume production, and the unpredictable nature of biomolecular systems.

Wisconsin Focuses on Path of Chemistry
For now, chemical conversion is the more immediate opportunity and fits within the current paradigm of processing energy and materials feedstocks.  And engineers are working to overcome the challenges to reduce the number of steps, and facilitate reactions at a lower temperature with non-toxic, abundant resources.

Now scientists at the University of Wisconsin-Madison have developed a two-step method to convert cellulose into a biofuel called DMF.  Professor Ronald Raines and graduate student Joseph Binder highlight the two step process:  First, they convert the cellulose of untreated biomass into the "platform" chemical 5-hydroxymethylfurfural (HMF) which is used in 'a variety of valuable commodity chemicals'. Generally HMF is made using processed glucose or fructose rather than raw biomass.

Step Two: Creating a New Biofuel with Gasoline Qualities

The next step is to convert the HMF into an ideal liquid biofuel 2,5-dimethylfuran (DMF) that has very similar properties to gasoline. 

The next phase for the research team is to increase the efficiency of the system.

'Taken together, the overall yield for this two-step biomass-to-biofuel process was 9 percent, meaning that 9 percent of the cellulose in their corn stover samples was ultimately converted into biofuel.'

"The yield of DMF isn't fabulous yet, but that second step hasn't been optimized," says Raines, who is excited about DMF's prospects as a biofuel. DMF, he notes, has the same energy content as gasoline, doesn't mix with water and is compatible with the existing liquid transportation fuel infrastructure. It has already been used as a gasoline additive.

In addition to corn stover, Raines and Binder have tested their method using pine sawdust, and they're looking for more samples to try out. "Our process is so general I think we can make DMF or HMF out of any type of biomass," he says.

The research was supported by the Great Lakes Bioenergy Research Center, a U.S. Department of Energy bioenergy research center located at the UW-Madison.

 

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Image Credit: frankh Flickr CC License

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