The In Situ Method

The relatively low cost and high availability of U.S. soybeans have led to their widespread use as the precursory feedstock for a majority of biodiesel production here today. Once the oil extraction and refining costs are factored in, however, the price tag can climb outside the realm of competitive viability. Enter visionary biochemist Michael Haas-a man shifting the paradigm of biodiesel production.
By Ron Kotrba | June 01, 2005
There is no question that biodiesel has become more popular than ever. Being popular, however, does not necessarily mean that it can compete with petroleum diesel in the open marketplace. Although strict industry standards put biodiesel on the same platform as diesel from a quality control perspective, many consumers still derive motivation from the pocketbook.

Even with the passing of the federal JOBS Creation Act of 2004--and taking under consideration the many benefits offered through the production of the renewable, home-grown fuel-biodiesel is not always cost-effective for consumers to buy. The biggest contributing factors to the high cost of biodiesel are the extraction and refining of virgin soybean oils, the most commonly used feedstock in the U.S. biodiesel industry.

Michael Haas, biochemist with the USDA Agricultural Research Service (ARS), developed a method of biodiesel production that cuts out the expensive intermediary. In situ transesterification-a biodiesel production method that utilizes the original agricultural component as the source of triglycerides for direct transesterification-eliminates the costly hexane extraction process and works with virtually any lipid-bearing material.

Officially, Haas (pictured above) is a biochemist with the Pennsylvania-based ARS Eastern Regional Research Center (ERRC) in the Fats, Oils and Animal Coproduct Research Unit. He has been with the ERRC since 1981. Haas received his undergraduate degree from the University of Minnesota in the Twin C ities and completed his doctoral studies at the University of Wisconsin in Madison.

Haas is an amiable fellow with a sense of realism about himself. "My core mission [at the ERRC] is to make biodiesel less costly and to make processes that will have relevance to the real world," he said. Not unlike the apple that fell on Sir Isaac Newton's head, so too did a revolutionary new way of producing biodiesel come to Haas out of "blue sky," in his words. "Oftentimes the best ideas come from outside the lab," he said. "I was swamped with my workload and in a meeting in Maryland. I was sitting there thinking about how to make biodiesel less expensive. I thought to myself, 'Soybeans are the predominant feedstock,' so I started there."

Haas and his team members-Bill Marmer, research leader over all ERRC projects; Tom Foglia, lead scientist and leader of this particular project; and Karen Scott (also pictured above), the technician "who does a lot of heavy lifting around here," as Haas said-forged ahead to develop the new cost-savings production idea. The in situ transesterification process was born. In situ is Latin for "in place."

When something is in situ, it is in its place of origin; in this case, the triglycerides are found in their place of origin-the lipid-bearing bean itself-rather than being utilized from extracted and refined oils, which necessitates an expensive middle step. This method provides "a different way to make fatty acid methyl esters," Haas said. "We started with the observation that most biodiesel is made from a rather finished agricultural material-fats and oils-and we asked, 'Would it be possible to consider the original agricultural material, say a flake-a lipid bearing component-as a source of triglycerides that could be converted to a fatty acid simple ester by direct transesterification?'" Haas imparted the concept by saying, "Consider the lipid source as a reservoir of the feedstock for biodiesel."

The workings within
In situ transesterification is surprisingly simple in principle. The process Haas and his partners followed in their research started with whole soy oilseeds rolling into the crushing plant. The hulls of the beans are removed, and the beans get cracked into quarter sections. The resulting soy fragments then pass between two large rollers, precisely adjusted to squash the quarters down to 0.38 millimeters in thickness and, as Haas explained, "designed for optimal hexane extraction," the most common method for oil removal. Haas' research began with the pressed soy flake quarters before they reached the hexane extraction process.

Although the research began with flakes right off the processing line, these flakes contained up to 10 percent moisture. The processing of the moisture-laden flakes consumed much more methanol, which means added dollars to the process, so Haas-true to his mission in cutting biodiesel production costs-looked into dried flakes for esters.

"[Once the soy flakes dehydrate], we then take the flakes and incubate them in a solution of methanol and sodium hydroxide," Haas said. "At room temperature and at ambient atmospheric pressures, the flakes are shaken [in the solution] for five hours. The result is anywhere from 95 percent to 100 percent transesterified fatty acid methyl esters." Haas' reaction to the project's success left him feeling optimistic and encouraged, albeit still cautious until more studies were completed.

Haas and company produced larger volumes of soy esters using this method. Series of tests were run to compare the fatty acid ester composition of the flake-derived biodiesel with results from conventionally produced biodiesel using refined soy oils, and Haas said, "We found that it very closely tracked textbook soy oil compositions."

Furthermore, "nearly 100 percent of the protein was retained on the flake, suggesting that the flake still has nutritional value as feed meal," Haas said. He noted that if the spent flakes did not retain nutritional value, the in situ method might not work economically. "The protein value of that feed is greater than the lipid value of that flake, thus the use of meal ... is an important part of the economics ... "

Not just soy anymore
"Although we originally designed this process as a way to eliminate hexane extraction, we became aware of the fact that it may be a generally applicable technology that could be used with other lipid-bearing materials," Haas said.

He and his team were aware of others working with meat and bone meal. Roughly 50 percent of a slaughtered animal is inedible. The remnants left over from slaughter are homogenized and treated at elevated temperatures, "then dried to produce a homogeneous material known as meat and bone meal," Haas said. Analysis showed that the homogeneous meal contained more than 9 percent triglycerides with high protein levels (47 percent) and low moisture content. The meat and bone meal was put through a similar process as the soy flakes, although at slightly elevated temperatures of 35 degrees Celsius. "The resulting esters compared very closely to that of tallow," Haas said.

Distillers dried grains with solubles (DDGS) was also investigated for use in this groundbreaking discovery of biodiesel production. Analysis revealed the DDGS also contained around 9 percent triglycerides with a slightly lower protein dry weight of 30 percent. Upon conversion, further analysis illustrated that the fatty acid methyl esters of the DDGS were very close in comparison to refined corn oil esters.

Haas said so far only one small study has been completed to study the nutritional value of the feed from these conversions. The study used 10 chickens, five of which were the control group while the other five were the study group. The results were favorable, but Haas said more needs to be done to make the coproduct a viable and scientifically reputable addition to the feed industry.

Another coproduct of the ester conversion is glycerin. Haas said the bulk of the glycerin from this process, regardless of what feedstock is used, ends up in liquid form. With his focus on esters, however, Haas hasn't spent much time worrying about the glycerin.

For those interested in reading more of the technical aspects and various analyses on the in situ transesterification process, a scientific paper co-authored by Haas appeared in the Jan. 2004 Journal of the American Oil Chemists' Society, Volume 81, No. 1, pages 83 through 89.

"When I was at the [National Biodiesel] Conference in Fort Lauderdale, there was a lot of talk about insuring your feedstock supply for those producing biodiesel because [according to some studies] biodiesel production will be cutting into the edible oil supply by 2010," Haas said. "This amplifies the issue of availability of feedstocks for biodiesel production. This method will provide a positive contribution as pressure gets put on prices for edible oils."

Haas said with this new process, meat and bone meal alone has the potential of producing 93 mmgy of biodiesel, while DDGS has the possibility of yielding more than 200 mmgy. With just these two coproducts alone, it is like 300 mmgy of biodiesel fell right out the clear, blue sky.

Ron Kotrba is a Biodiesel Magazine staff writer. Contact him by e-mail at [email protected] or by phone at (701) 746-8385.
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