CRN Looks at Future of Fly Ash

(Electric Co-op Today 07-08-2013) Electric cooperatives and other utilities in the United States are trying to identify more potential uses for fly ash to make sure abundant supplies of coal remain part of the nation’s energy resources. Basin Electric Power Cooperative’s Leland Olds Coal Station near Stanton, N.D., is among the coal-based power plants generating electricity.  NRECA’s Cooperative Research Network has spent more than two years on coal ash research with the University of Kentucky Center for Applied Energy Research, which was designed to help identify and develop new revenue streams for coal-based power plant operators.
“Technologies are starting to emerge to extract valuable products from fly ash,” said Robbin Christianson, senior director of operations of NRECA’s Cooperative Research Network.
“Other technologies could support multiple niche applications, none of which are currently mature or cost-effective, but with more research there could be alternatives to landfill disposal.”
The research is important because the Environmental Protection Agency has raised the possibility of regulating coal ash as a hazardous waste.
G&Ts rely heavily upon coal-based generation and could face millions of dollars in new fly ash disposal or storage compliance costs. So identification of new commodity markets capable of using the residuals will help control costs and could help offset other expenses.
“Instead of fly ash being a potential $50 per-ton liability, it could turn into a $10-$15 per ton asset,” said Dale Bradshaw an NRECA consultant and liaison for generation and environmental control technologies for CRN. “To go from a $15 million cost to a $3-$4 million benefit for a 600-megawatt power plant is a potential $20 million swing.”
Coal combustion produces about 140 million tons of fly ash per year, according to the Energy Information Administration.
The 73-page “Coal Combustion Ash Processing Technologies: A Review of the Current Status and Future Potential” was discussed during the Association of Rural Electric Generating Cooperatives Conference in Williamsburg, Va., June 23-26. The full report is expected to be made available to registered users of in the future.
CRN and some of NRECA’s member G&Ts have been testing one mercury control technology, which could help maintain fly ash as a marketable commodity.
The report also examines one company’s success treating fly ash with hydrochloric acid to produce a product usable in detergents, potentially creating a new market for the residue.
“Another promising area is the production of geopolymers, which are alkaline activated ash-based cements,” said Bradshaw, adding that the resulting product is comparable in performance to Portland cement, a common construction-grade product.
Recycled fly ash could also be used in production of porous paver bricks, which can help mitigate storm water runoff problems.
“To meet construction standards, fly ash needs to be less than 4 to 6 percent carbon,” said Bradshaw. “Some plants cannot use activated carbon to reduce mercury emissions because it contaminates the fly ash with additional carbon.”
To view the original article, go to: