Cooling coal emissions would clean air, lower health, climate-change costs

plants. The grant included a detailed engineering study by the Bechtel Corp. of San Francisco.

The Bechtel study showed that the cryogenic process would work very well, but noted that large quantities of carbon dioxide also would be condensed, a consequence that raised no concerns in 1978. “Today we recognize that carbon dioxide emissions are a leading contributor to climate-warming factors attributed to humans,” Donnelly said.

Out came his previously published work on this concept, followed by a rigorous two-year project to recheck and update his thermodynamic calculations and compose “a spreadsheet-accessible” formula for potential use by industry. His earlier work on the cryogenic treatment of coal-plant emissions and natural gas sources had sparked widespread interest internationally.

While the required cooling machinery would be large — potentially the size of a football stadium — the cost for construction or retrofitting likely would not be dramatically larger than present systems that include scrubbers, which would no longer be necessary, Donnelly said. The new journal article does not address construction costs or the disposal of the captured pollutants, the latter of which would be dependent on engineering and perhaps geological considerations.

According to the Physical Review E paper, carbon dioxide would be captured in its solid phase, then warmed and compressed into a gas that could be moved by pipeline at near ambient temperatures to dedicated storage facilities that could be hundreds of miles away. Other chemicals such as sulfur dioxide, some nitrogen oxides and mercury also would be condensed and safely removed from the exhaust stream of the plants.

Last December the U.S. Environmental Protection Agency issued new mercury and air toxic standards (MATS), calling for the trapping of 41 percent of sulfur dioxide and 90 percent of mercury emissions. A cryogenic system would do better based on the conservatively produced computations by Donnelly’s team — capturing at least 98 percent of sulfur dioxide, virtually 100 percent of mercury and, in addition, 90 percent of carbon dioxide.

This forward-thinking formula and the preliminary analysis by these researchers offer some exciting possibilities for the electric power industry that could ultimately benefit human health and the environment,” said Kimberly Andrews Espy, UO vice president for research and innovation.

Scientists at the University of Oregon are continuing to develop new ideas and advanced materials to foster a sustainable future for our planet and its people.”

— Read more in Charles E. Swanson et al., “Thermodynamic analysis of low-temperature carbon dioxide and sulfur dioxide capture from coal-burning power plants,” Physical Review E 86, no. 1 (6 July 2012) (DOI: 10.1103/PhysRevE.86.016103)