Bioprocessing engineer turns agricultural residue into energy storage material
It’s about transforming corn stover, dried distillers grain solids (DDGS) and even native grasses into a product more than 1,000 times more valuable—graphene.
The pyrolysis process turns plant materials into bio-oil and biochar, according to assistant professor Zhengrong Gu of the South Dakota State University agricultural and biosystems engineering department. When the bio-oil is further processed, it becomes biofuel.
Gu is converting biochar, a charcoal-like material, into graphene which can be used in place of expensive, activated carbon to coat the electrodes of energy storage devices—supercapacitors.
Small engines use start-up and run capacitors, Gu explained, but supercapacitors have more rapid charge and discharge rates as well as a higher energy storage capacity. Unlike conventional batteries, supercapacitors can withstand low temperatures.
To manufacture these storage devices, the United States now imports most of its activated carbon from Asia—including Japan, Thailand and China. “We can use these abundant agricultural materials as biofuel to reduce our dependence on petroleum and, at the same time, generate good active carbon to export,” Gu said.
Increasing product value
Gu estimated that approximately 2.2 pounds of graphene is worth at least $1,000. A pound of DDGS costs 7.5 to 9 cents and converts to approximately 7 ounces of graphene.
“That’s the increased value of the product,” Gu said. “We can convert agricultural residue to a high-value product that is easy to ship.”
Once the DDGS or corn stover is transformed to biochar, Gu mixes chemical called a catalyst with the biochar and heats the mixture to 1,292 degrees Fahrenheit for one hour to make porous graphene.
“It’s a one-step process,” he said. He estimated production costs, including feedstock, at about $1.36 for a pound of graphene.
Using the native grass big blue stem as the feedstock, Gu said, “we save more on feedstock.”
In addition, Gu hopes to adapt a new plasma processing technique developed at SDSU that reduces the processing time to five minutes and the temperature to 302 degrees Fahrenheit to convert biochar to graphene.
That could result in a significant cost savings, he added.
Optimizing material properties
Though Gu’s processing method generates graphene with the properties needed to capture and discharge electricity, he admitted, “We don’t know how the reaction happens.”
Through a $775,155 grant from the National Science Foundation along with $332,210 in university matching funds, Gu and a team of SDSU researchers studying carbon materials and biofuel technologies have purchased a transmission electron microscope will help advance this and other projects campuswide. The instrument should arrive this spring.
“We can find out how the process happens and learn how to change the parameters to improve the end product,” Gu said.
With the microscope, he and his team can determine the internal material structure and how the morphology changes its energy storage properties much like doctors use a CT scan to examine the human body, Gu explained. They can also find out whether biochar from one type of feedstock produces better graphene than another.
About South Dakota State University
Founded in 1881, South Dakota State University is the state’s Morrill Act land-grant institution as well as its largest, most comprehensive school of higher education. SDSU confers degrees from eight different colleges representing more than 175 majors, minors and specializations. The institution also offers 32 master’s degree programs, 15 Ph.D. and two professional programs. The work of the university is carried out on a residential campus in Brookings, at sites in Sioux Falls, Pierre and Rapid City, and through Cooperative Extension offices and Agricultural Experiment Station research sites across the state.
Christie Delfanian | newswise
Researchers discover natural product that could lead to new class of commercial herbicide
16.07.2018 | UCLA Samueli School of Engineering
Advance warning system via cell phone app: Avoiding extreme weather damage in agriculture
12.07.2018 | Leibniz-Zentrum für Agrarlandschaftsforschung (ZALF) e.V.
For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.
To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...
For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.
Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...
Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.
A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...
Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.
"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....
Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.
Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...
13.07.2018 | Event News
12.07.2018 | Event News
03.07.2018 | Event News
17.07.2018 | Information Technology
17.07.2018 | Materials Sciences
17.07.2018 | Power and Electrical Engineering