Improving the Process Without Breaking the Bank

There are ways to boost a plant's bottom line without intense capital investment. EPM takes a look at the options available for ethanol producers to do just that.
By Ron Kotrba | November 03, 2008
The big ethanol process-design firms have done good work to help optimize plant operations in various ways, and they continue to make strides in increasing yields while decreasing ethanol refineries' environmental footprint. Various fractionation packages are becoming more readily available, which allow producers more coproducts and choices, but fractionation requires some serious capital investment—and in the middle of what could end up being the worst financial crisis in history, it may be difficult to convince a plant or their financial institution that this is the way to go.

"Many of the points in the production process that relate to engineering have been optimized," says Gordon Burns, president of ETS Laboratories. "And the industry continues to develop new technology to improve the process." He tells EPM how Richard DeScenzo, a microbiologist with ETS, uses a black box at his booth during trade shows to represent the mystery of fermentation, which isn't a new metaphor. Broin Companies, now Poet LLC, used a similar prop at the 2006 International Fuel Ethanol Workshop & Expo, and then opened it to symbolize that they understood this important but mystifying step in ethanol production. Prior to that, EPM wrote a feature in January 2006 called "Unlocking the Black Box." No, it's not a new metaphor, but it is representative of some ethanol people's understanding of fermentation. "At the trade shows, you hear people saying this all the time, ‘We have great engineers and we've optimized our process, but we don't really have a handle on optimizing our fermentations,'" Burns says. "We hear that again and again.
Fermentation performance is an overlooked field for many in the ethanol industry. There are a lot of engineers and very good ones, and there are a lot of financiers, very good ones no doubt, and there are some microbiologists, but not in proportion to the importance microbiology plays in this whole process."

DeScenzo tells EPM he's been to six or seven ethanol-related conferences in the past year and only one of those shows, the FEW organized by BBI International, had a session on fermentation. "The focus was mostly on things like fractionation or maximizing distillation, and they're doing stellar work in those fields, but you don't hear much about fermentation—and what you do hear on fermentation primarily focuses on antimicrobials."

Use a Surgical Laser, Not a Shotgun
Since 1977, ETS has provided laboratory services to the fermentation industry—mostly wine, beer and spirits. "We're not a startup," Burns says. Some of the company's beverage clients also have fuel ethanol production interests. The spoilage organisms that affect production of alcoholic beverages are the same ones that contaminate fuel ethanol plants.

These microbes compete with Saccharomyces cerevisiae for vital nutrients, while their populations multiply exponentially, creating levels of acetic and lactic acids that can inhibit Saccharomyces growth.

ETS developed a microbiological tool kit called Scorpions, which detects the presence of the acid-producing bacteria and yeast in the mash instead of testing for their byproducts, or the acids themselves, like most conventional methods. "What we're detecting is the organism—that's the key difference—and what they're detecting is the metabolic byproduct that has to build up in concentration to where they can actually detect it," DeScenzo explains. In other words, the Scorpions detection kit can actually identify the presence of these contaminate organisms long before they have produced enough lactic or acetic acid to be detected using conventional methods of analysis. "What we're offering is an extraordinary technique that finds the beginning of the sickness if you will, and allows the plant to take proactive measures to prevent the illness, instead of finding out once they have an extreme problem," Burns says.

DeScenzo says, "In order to have enough lactic or acetic acid to be detectable you're looking at a population of 100,000 to a million cells per milliliter, but we can detect down to the 10-cell-per-milliliter range." Scorpions allows for the detection of bacteria in the incoming feedstock prior to milling and slurrying. "They can check feedstock as it's coming in and while they're building their yeast starters," DeScenzo says. With a four or five hour turnaround time, results can be in hand and intervention methods can be in play before any undesired microbe populations get out of control.

A growing population of contaminate organisms gone undetected can cause batch fermentation time to increase nearly two-fold, and in the case of continuous flow fermentation—not very common in dry-grind ethanol production because of the problematic issues with contamination—can reduce the alcohol content in the resulting beer. Either situation means money lost for the plant.

ETS offers two different service packages for ethanol producers. The first is more of a conventional forensics method using their novel microbiological approach, where plants can ship samples to ETS for a 24-hour turnaround time for results. The cost is $80 per sample to detect unwanted bacteria, and another $80 to detect contaminate yeast, like Brettanomyces. If both tests are requested, the cost is $140. There is another test available to detect Saccharomyces to make sure the population is growing as expected. The second service ETS can provide, and the proactive approach the company recommends for optimum effectiveness against contamination, is what Burns calls the turnkey solution.

ETS's turnkey solution involves setting up the laboratory at an ethanol plant with the necessary analytical equipment and proprietary reagents to detect the presence of contaminate organisms early in the process. So, rather than a forensics approach to identify what went wrong, plant operators can detect contamination early on and intervene to prevent loss of yield. ETS doesn't sell the required lab equipment but, if the ethanol plant doesn't already have the necessary equipment, ETS will help the plant lab personnel select what is needed. To be fully automated, a robotic device is used to extract the DNA from the contaminate microbes in the mash, and an instrument called a real-time thermocycler is used to amplify the DNA. "We sell a kit that contains the molecular probes needed for doing the detection, the Scorpions reagents that are very specific, and the technical support and training," Burns says. "If you started with nothing, the cost is about $120,000." Then, the in-house cost for each assay is about $30 versus the $80 per assay ETS would normally charge.

A big advantage of knowing precisely which organisms are present is the ability to tailor the treatment to those organisms. DeScenzo calls this ability to tailor treatment a "data-driven decision." Not all bacteria can be effectively treated with the same antibiotics. Dousing a plant with antibiotics using conventional testing methods detecting the presence of acids—especially when different microbes can produce the same acid—is akin to a doctor offering a single solution to different patients all exhibiting fevers. "It's a shotgun approach instead of understanding what the problem is, and designing a solution," Burns says. "It's a very ‘un-engineer-like' process to go after the problem with a shotgun rather than a surgical laser."

"We want people to think of this as a preemptive screening tool," DeScenzo says. If you can prevent these contaminate populations from getting to the point where it's impacting your fermentation efficiency, then you're saving money."

More Effective Cooking
The October EPM featured a story on Pursuit Dynamics Inc.'s ethanol reactor tower (ERT) titled "In Dynamic Pursuit of Efficiency." Then it was too early for any real data from the first full-scale trial of the equipment at Pacific Ethanol Inc.'s 40 MMgy Columbia plant in Boardman, Ore. The ERT is a pretreatment device that is positioned on the side of the liquefaction tank through which slurry enters prior to liquefaction. Using highly atomized steam that impacts the slurry to cause more cell disruption and activate more starch than a jet-cooker at lower temperatures, thereby decreasing liquefaction time, reducing alpha amylase requirements by 50 percent, speeding up fermentation and ultimately producing higher ethanol yields.

Ongoing trials at Pacific Ethanol's Columbia plant taught Pursuit Dynamics something about its equipment the company hadn't encountered before: The potential for buildup of "super beerstone." "We identified we were producing a deposit that was magnesium phytate," says Richard Eastman, president of Pursuit Dynamics. "For lack of a more technical term we call it super beerstone." The design and low-temperature operations of the PDX array—the individual reactors in the ERT—offered the perfect temperature and mechanical activity not only for the deposit to form, Eastman says, but for it to drop out. "Then it would coat the inside of the PDX array, reducing the tunnel bore size and eventually impacting the flow rate," Eastman explains.

What the company discovered through its full-scale trial at a 40 MMgy plant is that it needed the ability to clean in place (CIP), which meant adding one more array to its ERT. "While it takes two banks or two PDX arrays to run the 500-gallon-a-minute flow rate at Boardman, we added a third array and all the necessary controls," Eastman says. This gives the plant the ability to automatically valve one bank out and perform a CIP with a commercial cleaning solution. "So you're running a CIP cycle on each bank daily for one or two hours, and that eliminates the opportunity for buildup to take place," he says.

Part of Pursuit Dynamics' marketing strategy involves what Eastman calls creating "the greatest ease of entry possible," and he says the reoccurring income model helps with that. "No one's in love with the recurring revenue model, but all we're asking for is a very small part of a large number," Eastman tells EPM. The company has already signed a four-plant commercial letter of intent with Babcock & Brown, and involves the Denco LLC plant in Morris, Minn., the Castle Rock Renewable Fuels LLC facility in Necedah, Wis., Marquis Energy LLC in Hennepin, Ill., and Iroquois Bio-Energy Co. LLC in Rensselaer, Ind.

"The one common voice we're hearing says, ‘We are more than interested in looking at technologies that would deliver us a 10 percent yield benefit,'" Eastman says. "Everyone's situation is different, but 10 percent is 10 percent. And that could be the 10 percent that keeps your head above water."

The company states it still expects to see a 50 percent reduction in alpha amylase use as a result of employing its ERT, which alone could amount to a savings of a half-a-million dollars a year.

Atypical Product Diversification
Efforts to perform back-end oil extraction or the more capital-intense front-end fractionation to diversify and enhance coproduct streams continue to move forward, but a project between the National Corn Growers Association and Michigan State University looked outside the box of conventional coproduct diversification. The project involved the production of ethyl lactate through the combination of lactic acid and ethanol downstream of fermentation in a relatively simple process called reactive distillation. "The intention of this project was to try and provide some diversity for products from starch-based feeds, so producers could have more products to sell," says Carl Lira, MSU professor of chemical engineering and thermodynamics.

An ethanol plant could either outfit a small fermentation tank to produce lactic acid in a controlled manner on-site, or it could purchase lactic acid for reaction with the ethanol it already makes. Today ethyl lactate is predominantly produced in a complicated process by the petrochemical companies, and used in specialized market applications such as micro-circuit fabrication in the electronics industry, mainly because it's a clean solvent.

Richard Glass, NCGA vice president of research and development, says a 1 MMgy side stream of ethanol from a 25 MMgy plant for ethyl lactate production via reactive distillation, could produce the same revenue in the specialized chemicals market as the remaining 24 MMgy of ethanol sold into the fuel markets. The researchers were also able to demonstrate the ability to produce ethyl lactate at a profit while selling it at half the market value petrochemical companies typically charge. Lira says the production costs were closely tied to the selling price of lactic acid, so if an ethanol plant where fermentation is already a critical function could ferment some of its simple sugars into lactic acid using Lactobacillus, for example, thereby lowering the cost of obtaining the organic acid, then even better economics could be gained. "We were able to obtain a 30 percent return on investment and sell it for half the price of current market value," Lira says.

NCGA holds the license for this technology and is eager to discuss it with ethanol plants looking to diversify its coproduct stream in a manner unlike what's commonly investigated today. Glass says his dream is the integrated biorefinery where limitations arise only by one's own imagination and the ability to build the system. "You can make a lot of different value-added chemicals—glycols, epoxydes, ethers—everything but the oink," Glass says.

Ron Kotrba is an Ethanol Producer Magazine senior writer. He can be reached at rkotrba@bbiinternational.com or (701) 738-4942.