March 29, 2007

Engineering Students at NC State Develop New Techniques to Produce Ethanol and Methanol from Renewable Sources

Graduate and undergraduate student researchers within the Institute for Maintenance Science and Technology at North Carolina State University have developed two techniques using atmospheric plasma processing to produce ethanol and methanol from renewable sources. Observing a reaction in the atmospheric plasma chamber are (clockwise) Matthew King, Casey Holder, Patrick Davis, Kristina Marshall and Christopher Oldham. (Photo: Becky Kirkland)

There is a push in this country to find alternative fuels and to reduce the emission of greenhouse gases. Student researchers within the Institute for Maintenance Science and Technology (IMST) at North Carolina State University have developed new, cost-effective techniques using atmospheric plasma processing to produce ethanol from wood and other biomass and to capture methane, a greenhouse gas, and convert it into methanol.

Six students tackling these renewable energy projects are W. Patrick Davis, doctoral student in materials science and engineering (MSE); Casey O. Holder, MSE junior; Matthew R. King, senior in geology; Christopher J. Oldham, MSE doctoral student; Steven Disseler, senior in physics; and Kristina N. Marshall, MSE senior. The students are directed in their effort by Dr. Jerome J. Cuomo, Distinguished Research Professor in the Department of Materials Science and Engineering and director of IMST, and Bob Roth, also in the Department of Materials Science and Engineering.

Both techniques rely on atmospheric plasma (AP) processing to produce ethanol and methanol.

Plasma is a highly ionized gas that responds to electric and magnetic fields. Under the right conditions, it can produce chemical reactions capable of modifying the surface of materials. Traditional processes use low-pressure batch processing to produce plasma. The AP process makes use of a unique power supply that is able to produce atmospheric plasma in air, allowing for continuous processing at lower power for greater process efficiency. “The AP process cuts the cost of equipment,” King said. “The process can be run continuously and scaled to meet any process requirements.”

Oldham, King and Disseler led the project to convert biomass to ethanol using AP processing. They knew they had to disrupt the woody biomass structure to convert cellulose and hemicellulose — sugar polymers — into fermentable sugars. Lignin, another polymer, bonds cellulose and hemicellulose together, providing a structural support for the walls of the plant cells. Breaking these tough bonds posed a challenge.

		Undergrads in the Research Lab Dr. Jerome J. Cuomo (center), Distinguished Research Professor in the Department of Materials Science and Engineering and director of IMST, provides research opportunities to both graduate and undergraduate students. Pictured clockwise are Kristina N. Marshall, MSE senior; Casey O. Holder, MSE junior; W. Patrick Davis, doctoral student in materials science and engineering (MSE); Christopher J. Oldham, MSE doctoral student; and Matthew R. King, senior in geology. (Photo: Becky Kirkland) There are 15 undergraduates working directly for Cuomo at IMST. “I rarely deny an undergrad who asks for work,” he said. As a consequence, Cuomo’s undergraduate students get opportunities usually available only to graduate students. King not only had an opportunity to participate in graduate-level research, he also wrote research proposals and helped prepare a provisional application for patent. He plans to continue his work with Cuomo as a graduate student next year. Their work also makes these students attractive to potential employers. Marshall, who is graduating this year, has worked for Cuomo for two years. She’s been involved in multiple projects and has received a number of job interviews. “I’ve applied for eight jobs, and I’ve heard from five within a week of applying to them.” Another student, Holder, has a summer internship at Micron Technology, a semiconductor company in Boise, Idaho.

Traditional techniques such as acid hydrolysis and enzymatic hydrolysis have been used to disrupt the biomass structure, but they can be harsh, inefficient and energy-intensive. Corn stover, wood chips, switchgrass and other forms of biomass treated as waste are renewable resources. Converting these forms of biomass into fermentable sugars to produce ethanol in a more efficient, cost-effective way would help alleviate competing demands on corn to supply ethanol, food and feed.

Cuomo and his students knew they were able to do many things with AP.

“We mineralize organic substances, thus converting them to carbon dioxide and water vapor. We can kill bugs, which are organic, and wood is organic, but lignin inhibits the enzymatic process. So our first trial was to put some wood into the AP chamber,” Cuomo said. A few simple tests demonstrated ethanol production in the samples treated in the AP chamber.

With limited financial resources, the student researchers, on their own initiative, drew on the expertise of the university at large to help them conduct more rigorous research. Collaborating with the students are Dr. Jay J. Cheng, associate professor of biological and agricultural engineering; Dr. Simon E. Lappi, laboratory supervisor in the Department of Chemistry; Dr. Denis R. Cormier, associate professor of industrial and systems engineering; Dr. Mike Williams, professor of poultry science; Dr. Hasan Jameel, professor of wood and paper science; Kurt Creamer, engineering research associate in poultry science; and Dr. Lisa O. Dean, U.S. Department of Agriculture food technologist in the Department of Food Science.

These professors, along with their graduate students, provided training, equipment, analyses and even Southern Pine wood chips to the biomass research team as they worked to form and then refine their AP technique.

After 18 months of research, the team came up with a more efficient and cost-effective method of disrupting the biomass structure with AP. They call their technique “plasma-enhanced soft hydrolysis.” The technique pairs a dilute acid hydrolysis pretreatment with AP and has shown greater than 50 percent improvement in the production of fermentable sugars. The students presented their findings at the American Vacuum Society 53rd Annual International Symposium in San Francisco in November 2006. NC State's Office of Technology Transfer (OTT) has filed a provisional application for patent for their technique and is now pursuing a non-provisional application for patent. The NC State OTT is also seeking partners interested in commercializing this technology.

In addition to the biomass project, the students are working on another renewable energy project involving the conversion of hog waste into methanol. Davis, Marshall and Holder lead this project.

Unlike the biomass project, this research has some funding. In partnership with Orbit Energy Inc., IMST received a Phase I Small Business Technology Transfer (STTR) research grant from the U.S. Department of Energy. Orbit Energy, a local start-up company, provides technologies for converting organic waste into methane and carbon dioxide, two greenhouse gases. The goal of the STTR project is to develop a means of capturing and converting these gases into higher value organics such as methanol.

Waste materials from hog lagoons fed into Orbit’s high solids anaerobic digester produce a ratio of 67 percent methane to 33 percent carbon dioxide, which turns out to be the ideal ratio for making methanol from AP. “We are in our second design of the system,” Davis said. “We know how much methane and carbon dioxide we are putting in. We soon will be able to calculate our efficiency in terms of how much we are converting [into methanol].” With the help of Dr. H. Henry Lamb, associate professor of chemical and biomolecular engineering, the team will have the ability to identify each chemical produced by this process.

“The key here,” Oldham said, “is that, as a greenhouse gas, methane is 20 times more harmful to the atmosphere than carbon dioxide, and people don't really talk about that. We're taking that methane and making valuable alcohols and chemicals.” “The possibility and potential of this process is to sequester gases emitted from the flues of fossil fuel plants,” Cuomo added.

Both the biomass-to-ethanol and hog waste-to-methanol projects rely on AP technology. “Many people are looking at what AP can do,” said Cuomo. “Why are we different? We have [a power supply] that can be scaled to very large power levels . . . . The folks that are working with AP are mainly in laboratories like ours, but our connection is with industry — to take this to a commercial scale. We’re sequestering carbon, whether methane or carbon dioxide, and we’re seeing signs of carbon compounds that, once fully examined, may have more value than methane and carbon dioxide. We have ambition to do more. Our limitation right now is funding.”

— mcblief —

Technical Contact:
Dr. Jerome J. Cuomo, cuomo@ncsu.edu, 919-515-7218
Bob Roth, rcroth@ncsu.edu, 919-513-7902

Media Contact:
Kathi McBlief, kathi_mcblief@ncsu.edu, 919-515-2283

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