Dec 31, 2009 Energy Talks
University of Illinois at Urbana-Champaign researcher Agricultural Engineer Esha Khullar has found with close study that alternative ethanol production processes can produce more accessible products with better quality, a 20% boost in ethanol production plus saving waste and better efficiency. The choices for ethanol producers for profiting and answering product demands can be broader and more directed. There are new answers to the food vs. fuel debate as well.
A corn kernel is made up of three primary parts, the starch that is desired for ethanol production and some other starch and sugar based chemistry, the germ, which is the living seed where the proteins and most of the vegetable oil are, and the hard surrounding shell that offers fiber products to the market. Of these the oil and the germ are the most desirable parts for human consumption with high digestible protein and energy rich oil.
Currently the practice is to hammer mill, or to high speed whack the dry kernels into close to dust size particles that is simply faster than the even older process of grinding the kernels between two closely held stones. Both the ancient grinding method and the more modern hammer mill blend the three main parts into a more uniform raw material. Both methods need dry corn to work. It’s the time proven way to make ethanol.
What ethanol producers get out is ethanol and the distiller’s grain holding all the surviving proteins, oil and fiber products with the remaining unfermented starch.
What Khullar has researched is skipping the hammer milling or grinding and goes straight to the fractionating of the three main kernel parts by either a wet or dry method. In comparing the wet and dry fractionation methods, Khullar’s research team found that when using the wet fractionation method, the result is even higher ethanol concentrations coming out of the fermenter and better quality co-products than the dry method. That allows the proteins, oils and fiber to be marketed independently.
In the wet process, the corn kernels are soaked; washing the germ, which Khullar says is a cleaner separation. “There’s not a lot of starch sticking to the germ. That’s why you get higher oil concentrations.” After the kernels are soaked they are ground to produce a slurry. The slurry is soaked with enzymes that raise the specific gravity to a point where the germ starts floating and can be skimmed out from the top.
In the dry fractionation method, the kernel is just crushed, flattening out the germ. Khullar explains, “The germ is still attached to a certain part of the endosperm and you still have a few starch pieces sticking to it. You have a very high starch content germ from the dry fractionation and that lowers the oil content. That’s why there’s a big difference in the wet process compared to the dry process.”
Efficiency has driven the research as running the germ and the fiber through fermentation is pointless having no starch or sugar, so it’s wasteful. Khullar explains, “It’s better to remove them before the process. That way you have more starch in the fermenter. And you don’t have to heat them and bump them and cool them.” That saves energy inputs.
The process doesn’t require developing any new equipment. “It’s just a modification of things that are already being done in the corn processing industry and can be done pretty easily,” Khullar said. That might be a little overstated; some plant engineers will see major process revisions as plant layouts have evolved over the nearly three decades of building up the industry.
The major political payoff is the fuel ethanol business has the opportunity to answer the food vs. fuel debate with the high value products of protein, oil and fiber going to market instead of being lost in the distiller’s grain. In truth, cornstarch used to make high fructose corn sugar is even less healthy than just using plain sugar; so having less on the market would benefit some obesity issues.
The advantages are impressive.
20% more ethanol as more of the starch is going to fermentation, less energy inputs as the fermenting broth is “cleaner” without the fiber and germ going for the ride,
The proteins, oil and fiber can be sold independently for their value, distiller’s grain is greatly reduced saving more energy inputs to dry and process it.
Ethanol production is one of humanities’ oldest processes. The traditional process is well known and tested to huge scale. Khullar’s work shows the value of investigation and trying the steps in alternative forms to seek the most favorable result.
The surprise is not that the happened with such impressive results, but that it’s only been done now. A look at the paper’s abstract shows there is still a way to go.
The research team included Erik D. Sall, Kent D. Rausch, M.E. Tumbleson, and Vijay Singh. The University of Illinois and Monsanto Company provided the funding. The paper entitled “Ethanol Production from Modified and Conventional Dry-Grind Processes Using Different Corn Types” was published in the November/December 2009 issue of Cereal Chemistry.
Original post: New Energy and Fuel