Researchers develop chemical process to use cotton-gin residue

BLACKSBURG, Va., March 11, 2005 – Solving problems in the commonwealth's agriculture sector is part of Virginia Tech's College of Agriculture and Life Sciences' mission.

"Our goal is to add value to the cotton crop by using its residue to make a valuable product," said Foster A. Agblevor, professor of biological systems engineering in the college.

About 100,000 acres of cotton are grown in Virginia. The ginned cotton residue left at the processing plants contains the chemical ingredients commercially valuable products. The residue accumulates at the site and must be removed, otherwise it's a hazard because it easily ignites and can contribute to air pollution if it burns.

"We have been able to develop the manufacturing processes that can extract specific chemicals and make two products -- ethanol, which can fuel automobiles, and xylitol, a sugar.

"Our work developed 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's research team in Virginia Tech's College of Agriculture and Life Sciences has taken the cotton-gin residue and chemically processed the material in a laboratory. The processes extract the glucose to make ethanol and xylose that then can be made into xylitol. The Southeastern Regional Biomass Energy Program supported Agblevor's preliminary work.

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, the plant sites in Virginia are piled high with the residue," Agblevor said. "There is enough raw material to make it possible to have a manufacturing process there."

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