Alternative feedstock harvest successful

By Craig A. Johnson | September 15, 2009
The 2009 harvest season is underway and this year ethanol producers have stakes in more than just corn harvests.

Poet LLC, which first announced its corn cob harvest intentions in February, conducted its first commercial corn cob harvest throughout July in Texas, South Dakota and Iowa. Poet is in the process of converting its 50 MMgy corn-based ethanol plant in Emmetsburg, Iowa, to an integrated corn-to-ethanol and cellulose-to-ethanol biorefinery that will produce 125 MMgy of ethanol, 25 MMgy from corn cobs. Poet harvested close to 10,000 acres of cobs this year during demonstration harvests in the three states.

According to Poet, the company is interested in cobs as an economical, environmentally friendly feedstock for cellulosic ethanol. Additionally, researchers at Iowa State University conducting a five-year study on the impact of cob removal have first-year results that determined removing corn cobs from fields has no substantial impact on soil nutrient content, according to Poet.

Also involved in the 2009 cob harvest is Iowa-based agricultural equipment manufacturer Vermeer Corp. The company offered a limited number of CCX770 Cob Harvesters to North American famers for the 2009 harvest season. The wagon-style harvester, designed to tow directly behind select corn harvesting combines to collect and unload cobs, was available through direct rental from Vermeer.

"We believe that we have a machine that is going to go out and work and do the job, but we need to continue to stay close to the harvester and look for new opportunities in product development," product manager Jay Van Roekel said. "By renting [the harvester] it allows us to stay in close contact with our customers. That way we can train directly, we can set up the machines, and we can find out if there are any service issues."

Van Roekel said the first-generation cob harvester is a heavy-duty machine designed for large-scale operations. "It's really not the answer for a guy with 200 acres of corn," he said. "It's really too commercialized for that." Vermeer is continuing to work to develop solutions for those who would like to harvest cobs on a smaller scale, he added.

While those in the cellulosic ethanol industry have shown a great deal of interest in the product, Van Roekel said there is also interest in collecting cobs for other purposes, such as using cobs as a feed supplement for mixed rations, livestock and pet animal bedding, cogeneration with coal to produce electricity, and gasification. Cobs can also be in other industrial applications, such as construction materials, abrasives and absorbents.

A demonstration harvest of energy sorghum was also conducted this season. Research engineers at Texas AgriLife Research demonstrated sorghum modules made from a cotton module builder. The process begins with the harvester transferring the sorghum to a silage wagon. Next, the silage wagon travels to the module builder and transfers the material. The biomass is compressed into a module, and is then ready for a protective wrap to be applied before transporting to an energy facility. The wrap system protects the biomass from degradation until it is ready for transport to a conversion facility.
"Lambert Wilkes, with support from Cotton Inc., developed the technology with Texas AgriLife Research and solved how to harvest cotton and store it after transporting it from the field," said Stephen Searcy, an AgriLife Research agricultural engineer. "That's what we're trying to do in biomass logistics. It's very low energy density and takes lots of plant material."

Investigating how energy sorghum can be a sustainable crop in a farmer's portfolio is another aspect of the work done by AgriLife Research scientists and specialists with Texas AgriLife Extension Service. "We really see this crop as another the farmer can have in their portfolio," said Juerg Blumenthal, AgriLife Extension Service agronomist.