Scientists set to demonstrate new, cheaper and more efficient sorbent system

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Scientists set to demonstrate new, cheaper and more efficient sorbent system

Steve Benson, a carbon catcher par excellence at UND, is working on a novel technology for capturing carbon dioxide.

Benson, professor and chair of the College of Engineering and Mine's Department of Petroleum Engineering, is director of the UND Institute for Energy Studies. Along with a team that includes fellow faculty, students, and industry, he's developing a capture carbon technology that's both more effective and cheaper than currently available carbon capture methods.

This could be a major breakthrough in the world's ongoing carbon capture strategies.

Carbon dioxide is one of the main gases resulting from burning fossil fuels such as coal, gasoline and fuel oil. CO2 – a so-called greenhouse gas because it traps the Sun's heat – has been proved to be the leading cause of global warming. Thus we see efforts, such as Benson's, to figure out new and improved ways to capture carbon dioxide instead of releasing it all into the air.

The UND technology, called "CO2 Capture by Hybrid Sorption Using Solid Sorbents" (CACHYS, pronounced "catches"), will be available to power plants as well as facilities such as UND's own Steam Plant. Benson and his team, well-known experts in the field of flue gas emissions control, will test this technology on a pilot scale at the UND Steam Plant. President Robert Kelley has said he is supportive of using the Steam Plant for research and educational endeavors.

"In practice, capturing carbon dioxide is complex and currently very expensive," said Benson, who is closing out a year of development work on the CACHYS sorbent technology. "The big news is that our new sorbent technology is very efficient," Benson said. "We've come up with a technology that's cheaper – possibly a lot cheaper – and much more effective than existing technologies."

The team

The project got underway with $3.7 million in funding from the US Department of Energy and industry (ALLETE, SaskPower, and the North Dakota Lignite Energy Council) .

The CACHYS team includes Envergex LLC, a small research company located in Massachusetts. Benson is collaborating with Srivats Srinivasachar, Envergex's president, in the development of the CACHYS technology. Envergex and UND developed the original CACHYS concept with funding from the Department of Energy's Small Business Innovation Research Program. Barr Engineering, an architectural and engineering firm, and Solex Thermal Sciences, an equipment manufacturer, are other team members. The UND home team includes Dan Laudal, a research engineer, who is involved in the system design. Laudal is a graduate of Chemical Engineering. Harry Feilen, a Mechanical Engineering student, is building the slipstream system at the Steam Plant.

How does it work?

The CACHYS technology uses specially designed sorbents to capture carbon dioxide from flue gas streams, among other potential carbon capturing uses. The sorbent is created from low-cost materials that don't cause another environmental challenge. The sorbent with CO2 is then transferred to another vessel where the CO2 is desorbed, or released. The desorbed CO2 is then pressurized and transported to a site for use. The sorbent is then recycled for reuse to capture more CO2.

Benson and Srinivasachar note that capturing carbon dioxide probably works best when you trap it close to a source, such as UND's Steam Plant. Such places are called "point sources."

"Large stationary plants that burn coal, gas, oil, and the like, are big sources of carbon dioxide," said Benson. "Existing carbon capture technology at these point sources can be effective, but it is expensive and impractical."

Therefore, Benson and his team, including Envergex, are working on the CACHYS technology: it efficiently grabs carbon dioxide from whatever point source is producing it.

"We've passed the peer review process, now we're moving into the next stage," said Benson. "That involves testing our sorbent and process on the flue gas stream from the UND Steam Plant."

The testing will be controlled and monitored from two repurposed cream-colored truck containers stacked at the base of the Steam Plant's chimney. The goal is to prove the technology in intense daily use over the next year.

"It looks promising, and very efficient," Benson said. "It utilizes low-cost materials that won't cause environmental challenges."

"Also, our sorbents have better capacity," Benson said. "Basically, we're getting 7 to 10 grams of captured carbon dioxide per 100 grams of sorbent, significantly more than with competing sorbents, which can store only 2 to 5 grams."

Working with students

Another key factor in its importance to UND, Benson says, is that the CACHYS project employs many graduate and undergraduate students, providing a teaching and learning platform for the students.

"Now we're moving into the next stage – we're going to run in the slipstream at the UND Steam Plant, which will show the feasibility of our continuous process, both in terms of adsorption and the desorption of the carbon dioxide," Benson said.

Benson expects the CACHYS testing program to be up and running later this summer.

Juan Miguel Pedraza

University and Public Affairs writer

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