Green Car Congress: Using Biomass for Biodiesel

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Using Biomass for Biodiesel

3 June 2005

Conventional biodiesel is produced by the processing of the fatty acids in vegetable oils which are produced from an agricultural crop.

Researchers at the University of Wisconsin, however, have been working on a method to create a diesel fuel directly from the carbohydrates that constitute about 70%–75% of a plant’s dried weight—in other words, using more of a plant’s biomass as the feedstock rather than just the processed oil from its seeds.

The processing of biomass to produce a fuel usually takes one of three primary different routes:

Fermentation of glucose to ethanol
Pyrolysis or high-pressure liquefaction to convert biomass to bio-oil, which is then further processed
Gasification of biomass to create a syngas for use in a Fischer-Tropsch process

As reported in the current issue of Science, James Dumesic and his colleagues developed a process to convert plant carbohydrates directly to the long-chain hydrocarbon alkanes that constitute diesel fuel.

The process—Aqueous Phase Dehydration/Hydrogenation (APD/H)—combines hydrogen and alkane production.

Aqueous phase reforming of the carbohydrate feedstock creates hydrogen gas
Dehydration/Hydrogenation (using the hydrogen gas) produces the alkanes.

According to the researchers, the resulting alkanes contain 95% of the original heating value of the reactant.

So far the team has managed to produce hexane (C₆H₁₄)—a lighter alkane. One of the areas of concentration of the work now is to identify catalysts and reactor designs that can produce the heavier C₈–C₁₅ alkanes from biomass reactants.

The other major challenge, from a commercialization point of view, is how to extract the carbohydrates from the plant matter, and how “dirty” the stream can be. In the research, the team used a pure carbohydrate supply.

Resources:

Production of Liquid Alkanes by Aqueous-Phase Processing of Biomass-Derived Carbohydrates. Science,Vol 308, Issue 5727, 1446-1450, 3 June 2005 (subscription required)
Making Fuels from Biomass. Science, Vol 308, Issue 5727, 1421-1422, 3 June 2005 (subscription required)
Catalysis in Biomass Conversion: Hydrogen and Alkanes from Biomass-derived Molecules

June 3, 2005 in Biodiesel, Research | Permalink | Comments (4) | TrackBack (0)

Comments

Thanks for the very interesting and informative story. However, the title, referring to "Biodiesel," is misleading. Currently, biodiesel is generally taken to refer to a mixture of monoesters of long-chain fatty acids, such as methyl esters, and standards are being created that serve to codify this definition.

I think the body of the story is sufficiently clear in describing the new synthetic fuels as hydrocarbons (alkanes). And so far they have low molecular weights, more suitable for use in spark-ignition engines. A better term for referring to these biomass-derived fuels would be "biofuels."

I hope you may have other stories, still to come, in which researchers describe conversion of biomass directly to REAL biodiesel with comparably high efficiency.

Ernie Rogers

Posted by: Ernie Rogers | June 06, 2005 at 10:58 PM

pls send details to me about using biomass to get biodiesel

Posted by: chuks cyril | March 31, 2006 at 02:51 PM

Thanks for the very interesting and informative paper. However, the title, referring to "Biodiesel," is misleading. Currently, biodiesel is generally
it is very informative to any one in this world not only for the students ,scientics and researcher .plz give more information about this topic by sendiong me mail i will be very thank full to you .may i can provide u some usefull information .plz send some more information related to this process.i will wait ur email .

Posted by: ejaz ahmad bhatti | March 03, 2007 at 09:27 AM

Nice story! Can I use this for my blog? gr, remcowoudstra

Posted by: making biodiesel | July 06, 2008 at 12:53 PM