Chemical process developed to use cotton gin residue

Virginia Tech researchers are working on technologies that could create a new industry from a problem in the state’s cotton-growing region.

“Our goal is to add a value to the cotton crop by using the residue from the cotton to make a valuable product,” said Foster A. Agblevor, professor of biological systems engineering in Virginia Tech’s College of Agriculture and Life Sciences.

About 100,000 acres of cotton are grown in the Virginia counties of Southampton, Isle of Wight, Greensville, Sussex, and the City of Suffolk. After the cotton is ginned, the residue left at the processing plant contains the chemical ingredients for products that are commercially valuable. Currently, the residue piles up at the site and must be removed. Because it easily ignites, it can be a hazard, and if it burns, can contribute to air pollution. “We have been able to develop the manufacturing processes that can extract specific chemicals and make two products – ethanol, which can be a fuel in automobiles, and xylitol, a sugar. “Our work shows a manufacturing process for extracting both products simultaneously from the cotton residue so in the future it is possible that a manufacturing company operating in Southside Virginia could produce both the ethanol and the xylitol products,” Agblevor said.

Agblevor’s research has shown that the processes work in a laboratory. Along with students and technicians at Virginia Tech’s College of Agriculture and Life Sciences, Agblevor has taken the cotton gin residue and successfully chemically processed the material. The processes allow them to extract the glucose that can be used to make ethanol and the xylose that can be made into xylitol. The preliminary work was supported by the Southern Regional Biomass Energy Program. The project offers a solution to one of cotton production’s problems, he said. “Our estimate is that about 90 gallons of ethanol can be produced from a ton of cotton gin residue. At the end of a ginning season, plant sites in Virginia are piled high with the residue,” Agblevor said, “There is enough raw material that needs to be used to make it possible to have a manufacturing process there.”

An Iowa firm that produces ethanol from corn is interested in developing the technology. If the technology to use cotton gin residue can work efficiently at a pilot level, it will be possible to use the residue at a commercial level, which will not require government subsidies to make it economically viable. Currently, the production of ethanol from corn receives subsidies to make it profitable.