Sweet Catalysis

A chemistry professor at Wake Forest University has been working on a new catalyst for biodiesel production, and catalyzing his students to become biodiesel boosters.
By Susanne Retka Schill | December 21, 2009
Making biodiesel is a rather straightforward chemical reaction, and thus a suitable experiment for budding chemists to perform in a college class. Chemistry professor Abdou Lachgar's interest in biodiesel has continued to grow over the past decade since he started teaching such a class at Wake Forest University, a private liberal arts undergraduate college in Winston-Salem, N.C. "It wasn't about the price of oil then," he recalls. "Oil was $10 a barrel. The environmental impact of fossil fuels was on our mind." As a result, a group of professors got behind the idea of improving the environment by making their own biodiesel from waste vegetable oils and WFU Biofuels was born. A group of WFU staff enlisted the aid of students to collect waste vegetable oil and make biodiesel off-campus in the shop of a willing farmer nearby.

"Backyard biodiesel" production has it challenges though, as the industry well knows, when the free fatty acids (FFA) found in waste vegetable oils tend to make soap rather than biodiesel in the standard process. The solution is to add a processing step using a strong acid, such as sulfuric acid, to convert the FFA first before running the standard reaction on the remaining triglycerides with a base catalyst in an excess of alcohol. "Sulfuric acid is not easy to handle, it is quite corrosive and dangerous," Lachgar explains. "People have been trying to find a heterogeneous catalyst-a solid catalyst-that can do what sulfuric acid does."

Lachgar ran across a paper by a Japanese team on the development of a biodiesel catalyst for converting FFA. Following the description in the paper, Lachgar tested the method and found it worked, although it did have its issues. "The process they reported is quite involved and takes lots of energy to make. It involves heat and a very specific environment, it's lengthy and costly the way they made it," he says. "We found a basically straightforward way to make the catalyst, using sugar and quickly making a carbon-based catalyst that is acid in nature to convert the FFA to fatty acid methyl ester." He says the catalyst can be made from anything that is sugar-based, in chemical terms, such as corn syrup or cellulose. Instead of sulfuric acid, the esterification reaction is run with 1 to 2 percent of this sugar-based acid catalyst. "Most of our tests have been done with 100 percent FFA and the conversion is 95 to 98 percent within 30 minutes of treatment," he says. "It is a very good yield compared to other systems out there." The reaction occurs at 60 degrees Celsius, he adds, with the acid catalyst remaining solid and easily filtered at the end. Preliminary calculations indicate the cost of the catalyst is 7 cents per gallon of biodiesel produced. On the downside, the recyclability of the first generation catalyst, dubbed WFU BDC-1, is not good. While yield from the first reaction is 98 percent, it drops to 70 percent in the second use, to 54 percent in the third use and 28 percent if recycled a fourth time. Lachgar adds that the spent catalyst should be quite safe to dispose of.

Work continues in the chemistry labs at WFU, with undergraduate student help, to improve the longevity and develop a regeneration process as well as research the second generation of the catalyst. "We're trying to find a hybrid material, a composite made up of this catalyst and other things to make a catalyst that can do acid catalysis and base catalysis at the same time," Lachgar says. "There are a number of polymeric materials we've started to look at and make in the lab to see their effects."
Given that WFU is a liberal arts college and Lachgar's primary focus is teaching, the next steps in developing the catalyst-taking it to pilot and demonstration tests-are being handled by WFU's Office of Technology Asset Management, which is working with two interested companies, one in New Jersey and one in Hong Kong. A local company in Winston-Salem has been contracted to make samples of the catalyst for testing.

Tackling Trap Grease

Mike Wellet is looking at the WFU catalyst's applicability in waste water treatment facilities. "Anybody can make biodiesel from canola oil or fryer grease, we're trying to do it from trap grease," he explains. He works on chemical and process engineering as a partner in Prime Environmental Inc., a Morris Plains, N.J., firm that also works on environmental engineering, wastewater treatment, remediation and compliance.

Trap grease has a reputation as being a nasty, smelly disposal problem. Separated from municipal and industrial wastewater streams, it generally cannot be used as animal feed. Some places incinerate it and a few use bioremediation, but usually there's a cost for disposal. There is a lot of it, too. A decade-old study done for the National Renewable Energy Laboratory estimated 16 pounds of trap grease is generated per person per year in urban areas. It is far more difficult to handle as a biodiesel feedstock than waste vegetable oil, primarily because of its high FFA levels. Brown grease generally has 70 percent FFA while black grease is 90 percent FFA and higher, Wellet says.

Wellet used the WFU catalyst on trap greases supplied by a large East Coast wastewater treatment facility. "We were trying to simulate the real world as closely as possible," he says. "The catalyst performed really well." The reaction time for the different batches varied between two and four hours, he says, "Which is good because it normally takes eight to 10 hours. And you have a lot less glycerin and waste on the back end, which is also good."

He says some large municipalities have been interested in the work that his team at Prime Environmental is doing to develop a modular unit using the catalyst for biodiesel production from trap grease, which could be scaled up to 6,000 gallons a day. Part of the process will include cleaning the water, grit and other contaminants commonly found in trap grease before the conversion process. "[Wake Forest] really has something there that will impact the market," he adds. "But we're a little ways from actually being able to commercialize. We have to answer how long can you use it and how many pounds of the catalyst is needed to make X pounds of biodiesel. We're working through that now." 

Terrafinity targets student-based, campus biodiesel production
Students at Wake Forest University have formed a nonprofit group, Terrafinity Inc., with the idea of taking over the waste vegetable oil collection and small-scale biodiesel production begun by university professors. The small group of students has even bigger ideas than simply collecting oils and producing biodiesel: they would like to see the WFU project become a template for other college campuses to use for starting student-based renewable energy projects, and incorporate a Web platform for sharing technical information. "We want to create an open access research network where results of experiments would be shown, and any secrets would be revealed after the intellectual property was protected," says Wesley Johnson, one of the founders of Terrafinity. Renewable energy technologies could be given a big boost by open source platforms, he says, as demonstrated by their use in software development. Johnson is an undergraduate student at WFU majoring in biology with minors in environmental science and entrepreneurship. Business major Afton Vechery and political science major Lacey Robinson are the other two principles in the venture.

Vechery points out that biodiesel production occurs on many university campuses already. "Why doesn't everybody construct these and make their campuses more green?" Establishing a test model for student biodiesel production at WFU is the first step to spreading the concept to other small liberal arts colleges in the region. Biodiesel production may end up being only one of several green energy initiatives that could be launched by students, marrying education with research and entrepreneurship. "I'm a business major," Vechery says, "and it's been great to work with professors who want to catalyze student learning.

Susanne Retka Schill is assistant editor of Biodiesel Magazine. Contact her at (701) 738-4922 or sretkaschill@bbiinternational.com.
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