North Dakota Coal Company to Test New Uses for Carbon

 

 

By Jessica Holdman

May 21, 2017 - A regional power cooperative is developing methods for capturing and using carbon dioxide emissions that may impact the coal industry's larger struggle to reduce emissions and meet pending federal regulations.

Great River Energy is seeking funding from North Dakota's Lignite Research Council for two projects that, if successful, could be adopted by other facilities nationally and internationally.

"We think that (carbon capture research) is the key to unlocking additional efficiencies and revenue possibilities for North Dakota's coal reserves," Lignite Energy Council President Jason Bohrer said.

Bohrer said the research previously had been about survival, finding a way to meet federal regulations of coal power plants' carbon dioxide emissions, but now under the Trump administration, the impetus is more about economic opportunity.

"We didn't have the opportunity in the past because it was survive or die," he said. "Now we have the flexibility to look at our options."

Using Expansion Energy LLC's patented VCCS Cycle, GRE is aiming to find a way to use fly ash from its Spiritwood Station near Jamestown to capture carbon dioxide from its flue gas. And at the power cooperative's Coal Creek Station, it is considering the possibility of injecting flue gas into an onsite greenhouse.

For the VCCS process, GRE was approached by the technology's developer, a company familiar with North Dakota power plants with thoughts that Spiritwood would be a good fit, according to Sandra Broekema, Great River Energy's manager of business development.

The technology works by mixing flue gas with fly ash within a temperature-controlled vessel to create a reaction, allowing the carbon to be absorbed into the fly ash. The reaction creates two products: a solid called calcium carbonate and a methanol vapor.

The methanol vapor could be recycled back to the beginning of the VCCS process and reused to create the carbon capture reaction. The solid calcium carbonate is a consumable at Spiritwood and would be used within the plant to absorb sulfur dioxide, another pollutant, out of the flue gas, Broekema said.

Calcium carbonate is used at a number of power plants nationwide, making the technology, should it be proven, useful elsewhere, according to Broekema, who said GRE also could potentially use it to make a slake lime, which could then replace the lime, which is being used at GRE's Coal Creek Station to pull sulfur dioxide from flue gas, potentially saving money on materials.

And because part of the process relies on fly ash, Broekema said it could possibly be transferable to Powder River Basin coal plants, though it might require different ratios.

"We want to test the reaction using real flue gas and fly ash ... so we make sure the chemicals are right and the proportions are correct," Broekema said of the study, which would be entering its second phase of research if the funding were approved.

Phase I designed and estimated the capital costs for a modular VCCS pilot plant.

Phase II, which would take place this summer and continue through the fall, would utilize 100 pounds of fly ash in a lab setting, where the correct ratios for commercial use could be determined.

Phase III would result in a pilot project at Spiritwood Station.

Ancillary research in the Phase II study would test for rare earth elements known to be present in North Dakota coal seams, according to Broekema.

"Those are highly valuable products that are found in trace amounts, so that would really help the economics of this technology for a wider adoption," she said.

The U.S. imports 100 percent of its rare earth elements from overseas.

"If the U.S. could produce some of its own, that would be of both economic value and strategic value," Broekema said.

The greenhouse project was brought to GRE by North American Coal, which supplies coal to Coal Creek Station.

Rich Garman, senior project manager of business development, said GRE has toured two greenhouses attached to power plants in the U.S.: Boswell Station, which has been sending its excess warm water, since the mid-80s, to a nearby tree greenhouse as a source of heat and another natural gas-fired combined cycle power plant in central Utah, which has been attached for the past two years to Houweling's Tomatoes' 30-acre greenhouse.

"They seem to be reasonably successful," Garman said, of piping raw flue gas directly into the greenhouse. "We realize we have a different flue gas but it really intrigued us."

And GRE, along with North American Coal and Knorr Farms of Sawyer, is testing whether it could duplicate that at Coal Creek Station.

The greenhouse would get the benefit of heat and carbon, should the process work. And the study that GRE is seeking funding would be two-fold — determining the benefit of carbon to the plants and determining whether lignite coal flue gas would be effective.

North Dakota State University would be performing the plant studies using North Dakota varieties, seeing how much more carbon causes the plants to grow and how much carbon is wasted to determine the best levels of carbon. The school would also test carbon injection into soil in open fields.

The Energy and Environmental Research Center at the University of North Dakota would decide whether the flue gas would work or whether certain elements would have to be stripped out. At the Utah plant, the greenhouse mixes the flue gas with ambient air to achieve the right mixture, Garman said.

Steve Knorr, of Knorr Farms, said his family farm got involved because the greenhouse market is underdeveloped in the U.S. and he appreciates the opportunity to try to tie North Dakota's two largest industries, agriculture and energy, to find benefits for both.

Knorr said most of the major greenhouses supplying the U.S. are in Canada and Mexico. A commercial greenhouse on the prairie doesn't make a lot of sense but the benefits of locating near the power plant could change that.

"We're limited to our climate. The capability of a greenhouse is year-round production," said Knorr, who sees opportunity as the demand for locally grown food increases.