Ethanol from winter barley generates useful byproducts

By Lisa Gibson | November 11, 2009
Report posted Nov. 24, 2009, at 1:39 p.m. CST

In the process of developing winter barley as an ethanol feedstock, the USDA Agricultural Research Service's Eastern Regional Research Center, Wyndmoor, Pa., and its partners realized that biomass byproducts generated in the process can be used to manufacture biomass-derived fuels and coproducts.

The resulting barley straw, hulls and the ethanol coproduct distillers dried grains with solubles (DDGS) can be used to make bio-oil and biochar through pyrolysis, according to Kevin Hicks, research leader at the Crop Conversion Science & Engineering Research Unit at the ERRC. The bio-oil can be used as boiler fuel today, and with some improvements, could someday be used by petroleum refineries to make drop-in transportation fuels such as green gasoline and diesel, according to Akwasi Boateng, ERRC pyrolysis team leader. Biochar is a carbon-rich product that can be used to improve soil fertility and to sequester carbon in the soil.

Barley hulls and straw are fairly low-value feedstocks and their conversion to bio-oil and biochar is a win-win situation, Hicks said. Although DDGS is an animal feed ingredient, it occasionally may contain mycotoxins that would preclude that use, and under those circumstances, it can be used for other purposes, according to Hicks. An article about the work, written by ERRC Associate Researcher Charles Mullen and other co-authors, is published in the current issue of the Energy & Fuels, an American Chemical Society journal.

Only liter quantities of bio-oil are being produced now for testing, Hicks said, and its stability and quality need to be improved before it can be used widely. Small amounts of biochar are being produced around the world from fast pyrolysis and are being used for agronomic studies, including at the ARS. The market for biochar is developing and could become significant depending on what type of climate legislation is passed in the U.S., he said. "If farmers in the future can make money by sequestering carbon, the value of biochar would increase accordingly," he said. "If agronomic studies show positive impact on soil fertility and if use of biochar also sequesters carbon effectively, we expect much more biochar will be produced in the future," he said.

The barley-to-ethanol production project was a collaboration among ERRC, Virginia Tech, Genencor/Danisco and Osage Bio Energy, Glen Elen, Va. The winter barley used was produced by traditional breeding at Virginia Tech and the country's first winter barley ethanol plant is being developed by Osage Bio Energy in Hopewell, Va., called Appomattox Bio Energy. Osage has formed a partnership with Perdue AgriBusiness to supply barley from local growers and the plant will begin operation next spring, requiring between 20 million and 30 million bushels per year, Hicks said.

"So, if we are successful with our pyrolysis initiative, we will have helped create a sustainable agricultural industry based upon barley for production of ethanol and DDGS, but also green gasoline and diesel, and biochar," he said. East coast farmers will be able to grow the winter crop along with summer crops they already grow, avoiding competition with food production, he added. In addition, they can sell their barley straw to be converted to bio-oil and biochar soil amendments. The barley ethanol plant could also sell its hulls to a pyrolysis facility and will have a market for its nonfeed grade DDGS. "Everybody wins," he said.