This appears to be promising. We have here a way to convert a portion of the biomass product stream into a high energy density fuel. All prior work focused of ethanol which promised to be cheap and easy, but was also somewhat less energetic than we are used to.
Some interesting advances have been made on that front, but the end product of ethanol has always been problematic, needing a proper retooling of engine design to be properly optimized. It is hydroscopic after all.
A low cost upgrade of the fuel stream into a high energy fuel eliminates a lot of inconvenience.
As I have posted before, our science is in the process of converting biomass streams into a range of chemical feed stocks to produce useful end products. This is a huge undertaking that compares to the development of oil based products and surely more difficult.
Everyone can see the virtue of converting cellulose to glucose (its constituent molecule) and have known this since the nineteenth century. That is has not been done in a commercial plant as yet is a testament to the difficulty.
Yet this bit of work is clearly making natural processes work with us and for that reason alone is refreshing.
We still need a good substitute for high end hydrocarbon fuels at least to replace our reliance on oil products. That alone will end the rise in CO2 emissions globally. We certainly need it for heavy transportation of all kinds at least in a couple of decades and then likely forever after in some form or the other.
New Process Yields High-Energy-Density, Plant-Based Transportation Fuel
by Staff Writers
While biofuels such as ethanol are becoming more popular as blending agents in automobile fuels, they have limitations for use in jet fuel because of their low energy density. And, given present internal combustion engine designs, conventional biofuels cannot fully replace petroleum-derived hydrocarbons.
A team of University of Wisconsin-Madison engineers has developed a highly efficient, environmentally friendly process that selectively converts gamma-valerolactone, a biomass derivative, into the chemical equivalent of jet fuel.
The simple process preserves about 95 percent of the energy from the original biomass, requires little hydrogen input, and captures carbon dioxide under high pressure for future beneficial use.
With James Dumesic, Steenbock Professor of Chemical and Biological Engineering at UW-Madison, postdoctoral researchers Jesse Bond and David Martin Alonso, and graduate students Dong Wang and Ryan West published details of the advance in the Feb. 26 edition of the journal Science.
Much of the Dumesic group's previous research of using cellulosic biomass for biofuels has focused on processes that convert abundant plant-based sugars into transportation fuels. However, in previously studied conversion methods, sugar molecules frequently degrade to form levulinic acid and formic acid - two products the previous methods couldn't readily transform into high-energy liquid fuels.
The team's new method exploits sugar's tendency to degrade. "Instead of trying to fight the degradation, we started with levulinic acid and formic acid and tried to see what we could do using that as a platform," says Dumesic.
In the presence of metal catalysts, the two acids react to form gamma-valerolactone, or GVL, which now is manufactured in small quantities as an herbal food and perfume additive. Using laboratory-scale equipment and stable, inexpensive catalysts, Dumesic's group converts aqueous solutions of GVL into jet fuel.
"It really is very simple," says Bond, of the two-step catalytic process. "We can pull off these two catalytic stages, as well as the requisite separation steps, in series, with basic equipment. With very minimal processing, we can produce a pure stream of jet-fuel-range alkenes and a fairly pure stream of carbon dioxide."
While biofuels such as ethanol are becoming more popular as blending agents in automobile fuels, they have limitations for use in jet fuel because of their low energy density. And, given present internal combustion engine designs, conventional biofuels cannot fully replace petroleum-derived hydrocarbons.
"The hydrocarbons produced from GVL in this new process are chemically equivalent to those used in the present infrastructure," says Alonso. "The product we make is ready for the jet fuel application and can be added to existing hydrocarbon blends, as needed, to meet specs."
The biggest barrier to implementing the renewable fuel is the cost of GVL. Until now, says Dumesic, there has not been an incentive to mass-produce the compound. "The bottleneck in having the fuel ready for prime time is the availability of cost-effective GVL," he says.
Now that they have demonstrated the process for converting GVL to transportation fuel, Dumesic and his students are developing more efficient methods for making GVL from biomass sources such as wood, corn stover, switchgrass and others. "Once the GVL is made effectively, I think this is an excellent way to convert it to jet fuel," he says.
