ADVANCED BIOFUEL¦ of which is ionic liquid pretreatments with The next step in developing this prebutadiene sulfone. treatment method will focus on optimization experimentation. Researchers may also try different levels of solids loading, de Frias Salty Solutions Some of the newest pretreatment in- adds. Halfway across America, the JBEI in novations involve the use of ionic liquids to break apart biomass into cellulose, hemicel- California is also developing an ionic liquid lulose and lignin. Ionic liquids, or liquid salts, pretreatment. Unlike the University of Illiare being researched at both the University nois’ butadiene sulfone method, the institute of Illinois at Urbana-Champaign and the is utilizing imidazolium chloride with mixed feedstocks. With its pretreatment technology, U.S. DOE’s Joint BioEnergy Institute. Initially, the university’s research using the institute is able to liberate 95 percent sugthe ionic liquid butadiene sulfone to pretreat miscanthus began for a different purpose. In the beginning, the lab was using the liquid to solubilize pure cellulose. What the researchers discovered was the biomass did not solubilize, but instead developed similar physical characteristics of pretreated material. “It actually looked very similar to what we used to do in our lab—two-stage, alkali-acid pretreatments—but in this case, one step,” de Frias explains. “Initially, we wanted to find a solvent to actively separate lignin, hemicellulose and cellulose,” adds Hao Feng, associate professor at the University of Illinois. “However, we also found it is probably better to use this as a pretreatment because we can recover it, we can recycle it, and that way we can have that green, sustainable production.” Using butadiene sulfone as a pretreatment offers several benefits. De Frias says the most important advantage of this method is that the solvent’s recovery process is industrially available at mild to higher temperatures. During pretreatment, he explains, the solvent decomposes into 1,3-butadiene and sulfur dioxide at 90 to 110 degrees Celsius (194 to 230 degrees Fahrenheit). In the presence of water, the sulfur dioxide changes to sulfurous acid. Together, the sulfurous acid and butadiene sulfone provide a “dual attack” to the plant cell walls, freeing over 90 percent of the hemicellulose, releasing 90 to 99 percent of the cellulose and almost 60 percent of the lignin. Once pretreatment is complete, the temperature is increased, and the heat breaks down the solvent, forming butadiene learn more... and sulfur dioxide. The two gases are then hurstboiler.com recombined to form the original butadiene sulfone.
ar yields from biomass in less than 24 hours, recovering roughly 95 percent of the ionic liquid. Blake Simmons, vice president of the deconstruction division at JBEI, says using these “molten salts” may provide additional benefits. He explains ionic liquids can produce high sugars yields from any feedstocks. “We’ve actually asked for feedstocks from folks that they think are really recalcitrant , including pine, and we can still efficiently liberate sugars from those,” says Simmons.
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