As high corn prices squeeze the profitability of traditional ethanol production, some industry analysts are looking at ways to increase revenues from its coproducts. In some cases, it makes sense to extract more value with a shift in the production process.

Mike Kessler, CEO of United Biofuels Development, says of the several general methods used to make ethanol today, a "short-steep" process is gaining in popularity. It's being implemented in one operational Wisconsin plant and projects under construction in Ohio and Indiana. The short-steep process is defined as a method similar to the dry-grind process, except that it continuously wets the corn before grinding instead of after.

"The short-steep process has a moderate initial cost with a good return on investment," Kessler says. "The process is an alternative way to extract value-added products in lieu of distillers dried grains with solubles (DDGS). The methods used provide a continuous process for better ethanol yields and lower overall operation costs."

While dry-grind ethanol plants are the most popular choice for new construction, Steve Eckhoff, University of Illinois professor of agricultural and biological engineering, says recovering additional coproducts from corn prior to the process presents a dilemma.

"The goal of pre-separation or post-separation is to recover as cleanly as possible the non-fermentable components of the corn: fiber, oil, protein and ash," he says. "In order to maintain low cost, it is desirable to do minimal processing but get maximum value from recovered coproducts. It is a balancing act between recovery of non-fermentables and loss of ethanol production. If you increase the recovery, you invariably increase starch loss. Generally, as recovery increases, purity of the recovered fraction decreases."

Eckhoff says non-fermentables are concentrated in the corn's pericarp (coarse fiber) and germ (embryo). More than 50 percent of corn's non-fermentables are found in the 17.2 percent of kernel weight that makes up the germ and coarse fiber. Eckhoff says three wet fractionation processes exist for recovering these non-fermentables, including a patented Quick Germ/Quick Fiber (QQ) process that uses conventional wet milling equipment to recover germ and coarse fiber. A six- to 12-hour soak in process water prepares kernels for coarse fiber and germ coproduct recovery. The QQ process is licensed from the University of Illinois, by Maize Process Innovators (MPI) and Eckhoff serves as a consultant to the company.

Another option is the trademarked LAI-PRO Bio Grind, a continuous process which industry consultant Leon Langhauser of Decatur, Ill.-based Langhauser Associates Inc. says provides a similar way to extract coproducts for savings as economic market conditions dictate.

"Those that use milling for separations experience poor yields and high costs," Langhauser says. "It is better to utilize the whole corn plant beyond just alcohol and DDGS to include such value-added coproducts as oil and meal, low-starch fiber, fermentation media, high-protein concentrate for ruminant and non-ruminant animals at higher percentages of their rations, and food-grade products for humans. Our process separates the kernel into four economical portions and removes them before there is a chance to lose nutritional value or the best possible ethanol yield."

Langhauser says low-starch fiber extraction provides an economical cellulosic feedstock that can produce 60 to 75 gallons of ethanol per ton using current technology. In addition, he stresses the residual hemicellulose and lignins (the only portion with no food value) can be used to fuel the operation.

The LAI-PRO Bio Grind process uses standard, proven-process equipment and technology. Langhauser says operators can reduce the size and operating costs of the fermentation and distillation plant by 11 percent or increase throughput rate by the same margin. Operators see continuous process savings in equipment, construction, operation and control. Langhauser says a producer can obtain 4 percent to 50 percent revenue gain with the process over traditional dry-grind plants, depending on the coproducts produced.

A small change in coproduct composition can significantly affect revenue, Eckhoff says of the QQ process. "Most of the increased revenue comes from the additional oil recovered and the increased value of DDGS with additional protein and lower (neutral detergent fiber)," he says. "There is also a small amount of additional ethanol."

Eckhoff's mass balance-based spreadsheet model comparing fractionation processes is part of a research grant looking at the competitiveness of smaller dry-grind plants. Eckhoff's 40 MMgy plant model uses current economic conditions and the best available data for milling yield and coproduct composition. The model finds QQ has a significant advantage over dry-grind pre-fractionation and conventional processes.

"The QQ process increased net revenue by 41.6 percent with a 1.4-year payback period compared to dry fractionation, which increased net revenue by 6.5 percent with an eight-year payback," Eckhoff says. "Consulting engineers report projected cost of the systems to be similar, but the cost can be off 100 percent or more and not affect the outcome of the comparison. Increased value for QQ comes from improved DDGS and from an increase in the number of gallons of ethanol each turn of the fermenter produces. Even if real-world cost and performance data differ from my model, there is no reason to expect relative values to change. QQ should outperform dry fractionation."

Langhauser also touts pre-fractionation's benefits. "You save considerable energy with lower viscosities, and use mechanical grinding, dewatering and concentration rather than high-energy use evaporators and driers," he says. "Our system can use the new raw starch hydrolysis enzyme technology with recycle capacity. You can sanitize scrubber and wash water with recycle steam without affecting pasting, and control propagation and growth of contaminants without sulfur compounds and other chemicals. You can also feed the fermenter 40 percent soluble solids to use very high gravity technology."

Eckhoff says pre-grind separation is generally better than post-grind separation, and wet fractionation is generally better than dry fractionation. "Make sure you understand the basis of yield numbers for a process, and do your homework on the economics," he says.

For more information, visit www.maizepi.com or www.langhauserassociates.com.

Pre-Fractionation Process Considerations
Eckhoff says selection of a pre-fractionation method should be based on the following considerations:

1. Equipment cost: Patented systems generally carry an annual or upfront technology fee which should be amortized with the capital.

2. Suitability of process to needs: Determine how close you are to companies who buy germ, whether or not you want to press out oil, the composition of your local feed market and whether that market can consume all you produce.

3. Coproduct markets: If the process you choose produces DDGS with improved value, no economic benefit exists if you have no market. Newer coproduct value is hard to discern, and initially the livestock industry may not readily discriminate between them.

4. Economic comparison: Get a head-to-head comparison by inputting yield and compositional data for the coproducts into a mass balance-based model. All parameters should be the same for each process except where actual data can substantiate changes.

5. Maintenance: How much maintenance or additional manpower is required to operate? Could a failure in the add-on process cause a shut down or just a distraction?

6. Complexity: Determine whether you will require special equipment or technical help.

For more information, visit www.ag-bioeng.uiuc.edu.

Capitalize on Biomass
If you're looking for innovative ways to improve profitability from a dry-grind ethanol plant, research at the University of Minnesota may have some answers for you.

"Dry-grind ethanol plants have the potential to reduce operating costs and improve net energy balances by using biomass as the source of process heat and electricity," says Douglas Tiffany, University of Minnesota agricultural economics research fellow. "Our research team established baseline levels for plant rates of return with natural gas at $8 per dekatherm and DDGS selling for $100 per ton. Rising natural gas prices, falling DDGS prices, and premiums paid on low-carbon imprint ethanol from biomass all swing the economic advantage to the biomass options we have explored."

Tiffany says replacing natural gas and largely coal-based electricity with renewable biomass reduces the carbon imprint for ethanol. "This will have enhanced value in the ethanol marketplace, lead by California's low carbon fuel standard," he says. "Many states have bold goals that specify percentages of renewable electricity in portfolios sold by utilities operating in the state. These mandated levels may provide incentive for utilities to bid more for electricity generated at ethanol plants."

Tiffany and University of Minnesota agricultural engineers Vance Morey and Matt De Kam identified various technology bundles of equipment, fuels and operations that are capable of satisfying energy needs and emissions requirements for 50 MMgy and 100 MMgy capacity dry-grind plants using DDGS, syrup and/or corn stover.

The research finds DDGS byproducts are an attractive biomass fuel because they exist at dry-grind ethanol plants in sufficient quantities to provide all process heat and power, and renewable baseload electricity that can be sold on the grid. Stover is also an attractive biomass fuel because it is typically plentiful in the vicinity of dry-grind ethanol plants and may be easier to gasify than DDGS, although logistical issues using the material as fuel exist.

For more information, visit www.biomassCHPethanol.umn.edu.

Barb Baylor Anderson of Anderson & Associates is a freelance agricultural writer from Edwardsville, Ill. Reach her at anderagcom@sbcglobal.net.

The claims and statements made in this article belong exclusively to the author(s) and do not necessarily reflect the views of Ethanol Producer Magazine or its advertisers. All questions pertaining to this article should be directed to the author(s).