By Celsias Team
Posted on Aug. 25, 2010. Listed in:
The cost of transporting biomass is often viewed as an economic barrier because of its bulk volume, but thanks to a method developed by chemical engineers at Purdue University, that barrier may be a thing of the past. They’ve developed a new method to process agricultural waste and other biomass into biofuels, and they are proposing the creation of mobile processing plants that would rove the Midwest to produce the fuels.
"What's important is that you can process all kinds of available biomass -- wood chips, switch grass, corn stover, rice husks, wheat straw …," says Rakesh Agrawal, professor of Chemical Engineering.
"Material like corn stover and wood chips has low energy density. It makes more sense to process biomass into liquid fuel with a mobile platform and then take this fuel to a central refinery for further processing before using it in internal combustion engines."
The new method is called fast-hydropyrolysis-hydrodeoxygenation and works by adding hydrogen into the biomass-processing reactor. The hydrogen for the mobile plants would be derived from natural gas or the biomass itself. Making the project potentially even more sustainable, Agrawal says that in the future, there’s a possibility to use of solar power to produce the hydrogen by splitting water, making the new technology entirely renewable.
Findings are detailed in a research paper appearing online in the journal of Environmental Science & Technology. To check out the finer details and read the research paper, click here.
The paper outlines the method, showing how a portion of the biomass is used as a source of hydrogen to convert the remaining biomass to liquid fuel.
The new method would produce about twice as much biofuel as current technologies when hydrogen is derived from natural gas and 1.5 times the liquid fuel when hydrogen is derived from a portion of the biomass itself.
Biomass along with hydrogen will be fed into a high-pressure reactor and subjected to extremely fast heating, rising to as hot as 500 degrees Celsius, in less than a second. The hydrogen containing gas is to be produced by "reforming" natural gas, with the hot exhaust directly fed into the biomass reactor.
"The biomass will break down into smaller molecules in the presence of hot hydrogen and suitable catalysts," says Agrawal. "The reaction products will then be subsequently condensed into liquid oil for eventual use as fuel. The uncondensed light gases such as methane, carbon monoxide, hydrogen and carbon dioxide, are separated and recycled back to the biomass reactor and the reformer."
Purdue University is so confident in the discovery, it’s filed a patent application on the method.
Image: Flickr - jurvetson
