Madison (WI) - Researchers at the University of Wisconsin have developed a two-step process which converts the raw cellulose of biomass into a promising fuel. The process is described in the February 11 issue of the Journal of the American Chemical Society, and is "unprecedented in its use of untreated, inedible biomass as the starting material."
The process involves two steps, the first of which breaks down the cellulose into what research call a "platform chemical." In this case, it's 5-hydroxymethylfurfural (HMF), which reportedly can be converted into a "variety of valuable commodity chemicals."
According to Ronald Raines, a biochemistry professor at the university, "Other groups have demonstrated some of the individual steps involved in converting biomass to HMF, starting with glucose or fructose. What we did was show how to do the whole process in one step, starting with biomass itself."
The key is a unique solvent developed by Raines and graduate student Joseph Binder. The chemical has a patent pending, and is small enough to bypass the lignin "cages" which surround cellulose, making it extremely difficult to break down. The solvent they use is capable of fully dissolving cotton balls, for example, which are pure cellulose. The solvent has the added benefit of not being corrosive, dangerous, expensive or even "stinky," according to Raines.
Step two involves converting the HMF into 2,5-dimethylfuran (DMF), which is a "promising biofuel." According to Raines, the conversion rate is 9% efficient, meaning that about 9% of the cellulose input is ultimately converted directly into the biofuel.
Raines said, "The yield of DMF isn't fabulous yet, but that second step hasn't been optimized." He says DMF has the same energy content as gasoline, does not mix with water and is compatible with the existing "liquid transportation fuel infrastructure" and has already been used as a gasoline additive.
So far, the researchers have used corn stock cellulose, called "corn stover," as well as pine sawdust. The team believes the process could be applied to any form of raw biomass.