By A'ndrea Elyse Messer
Public Information
High-value carbon products like activated carbons may become a commercially viable byproduct of the new, environmentally friendly methods used to burn coal, according to a researcher.
"To meet environmental standards for low nitrogen oxide (NOx) emissions, we have redesigned the way we burn coal," said M. Mercedes Maroto-Valer, research associate in Penn State's Energy Institute. "We resolved the environmental problem, but we created other problems."
Coal-fired plants now use low NOx burners to reduce emissions. These burners do the trick, but increase the amounts of unburned carbon left after combustion. Power plants are left with a mixture of fly ash and unburned carbon.
"Before low NOx emission requirements came into being, power plants marketed the fly ash remaining after burning to the cement industry. However, with the higher levels of unburned carbon, this waste byproduct can no longer simply be sold," Maroto-Valer said. "Now power plants must dispose of the fly ash and carbon mixture and disposal is expensive."
Maroto-Valer; Darrell N. Taulbee, industrial support coordinator for the Center for Applied Energy Research, University of Kentucky; and Harold H. Schobert, professor of fuel science and director of Penn State's Energy Institute, are investigating both fuel and non-fuel uses of coal for the 21st century. One use for both combustion waste and anthracite coal is as activated carbon.
Wood is the traditional source for activated carbon, which is sometimes called activated charcoal. Activated carbon traps impurities found in both gases and liquids in pores within the carbon. These carbon products have a huge market, with 350,000 tons sold each year for water treatment, gas purification, gold extraction and other uses. Products as diverse as air conditioning systems, household water purification pitchers and cigarette filters use activated carbon.
"We know we can separate the fly ash from the unburned carbon, and sell the fly ash to cement manufacturers," said Maroto-Valer. "However, until recently, uses for the remaining carbon were unknown because no one had characterized the unburned carbon."
The researchers used both the unburned carbon and anthracite coal to create activated carbon and compared the results from both. After separation from the fly ash, they activated the unburned carbon with steam at 850 degrees Celsius. The unburned carbon contained few volatile components because it had already been heated while in the combustor. The researchers crushed the anthracite before treating it with steam.
"It appears that the unburned carbon is suitable for manufacturing activated carbon products," said Maroto-Valer. "We get high surface area after short activation times and with product yields over 70 percent."
Activated carbon from wood products has about 10 percent yield. The anthracite coal activated for the same amount of time as the unburned carbon had about 59 percent yield, but higher surface area, and the anthracite activated for slightly longer had 33 percent yield and even better surface area.
"If we activated the unburned carbon for longer, we would probably get better surface area at the expense of some yield," said Maroto-Valer.
While both anthracite and unburned carbon can produce acceptable activated carbon, unburned carbon is probably less expensive and better for the environment. Also, while anthracite sells for about $50 a ton, the waste from power plants can be separated for $10 to $15 per ton, and the fly ash could be sold to cement manufacturers.
To most gardeners, weeds are evil intruders to be eradicated by any means necessary. Don't be so quick to pull them -- some weeds are quite nutritious, said a horticulture expert in the College of Agricultural Sciences.
"Many weeds are higher in vitamins than most of the entrees served in a restaurant," said Peter Ferretti, professor of vegetable crops.
Ferretti said that most edible wild weeds have been consumed by humans for centuries -- dating back to before the Stone Age. Only since the dawn of modern agriculture has the wondrous taste of wild weeds disappeared from the human diet.
Still, Ferretti warns that fledgling gourmets should not indiscriminately fry up the compost pile as an entree.
"Only eat plants you have positively identified as edible," Ferretti said. "Even after positive identification, eat just a small amount of it in case of an allergic reaction." Ferretti also said weed-eaters should never harvest edible wild plants that are growing in protected sanctuaries, on private land, near well-traveled roads and highways, or near rights of way or farm fields that may have received pesticide drift.
Ferretti offers insights into a few common and easily identified wild weeds and plants.
n Dandelions. The green leaves of tender or blanched plants can be eaten raw in salads. Older plant leaves can be cooked. The yellow flowers are the primary ingredient in dandelion wine.
n Wild chicory. The root can be dried and ground and used as a coffee substitute. The young leaves are good in mixed salads.
n Wild mustard. This weed should be picked quite young, or just before its flowers come out.
* Watercress. Watercress' spicy taste makes it perfect as an addition to salads or soups, as a sandwich filler or chopped up in scrambled eggs.
* Purslane. The thick, glossy leaves can be used in salads.
Outsourcing is fine for some company functions but not for telephone "hot lines" that allow employees to report ethical or legal violations, said researchers.
"Our studies indicate that companies are better off to retain responsibility for reporting and investigating ethical violations in-house," said Linda Klebe Trevino, professor of management in The Smeal College of Business Administration.
"When employees take time to report ethical or legal violations, they need to believe that the company is interested in receiving these calls, takes them seriously and will commit resources to investigate and follow through. A company insider is more likely than an outside firm to leave that sort of symbolic message with callers," Trevino said.
For more information on this research, check the Web at http://www.psu.edu/ur/NEWS/news/ethicsoutsource.html.