Research
Penn State Intercom......September 21, 2000

Lard-fired boiler found to burn
cleaner than one using fuel oil

By A'ndrea Elyse Messer
 Public Information

RESEARCH_Miller2Pork producers who pride themselves on using every part of the pig except the oink have seen the use of lard in cookies, chips and other foods decrease.

In search of alternative outlets should the lard become unmarketable, a team of researchers has found that lard and choice white grease can replace Nos. 4 and 6 fuel oil in a process steam boiler with little or no retrofitting.

"Today, the lard produced when processing a pig is used in restaurants, bakeries and cosmetics while the choice white grease is used in animal feedstuffs and as chemical feedstock," said Bruce G. Miller, associate director of the University's Energy Institute. "The market for both edible lard and non-edible choice white grease is changing and Hatfield Quality Meats investigated new options for their products."

A butchered hog is 60 percent meat and 40 percent other products. Of that 40 percent, 20 percent becomes products like processed lard and the other 80 percent becomes animal feed, including choice white grease. In 1998, Hatfield was processing about 7,000 pigs per day, averaging 250 pounds per pig. If the markets for lard or choice white grease should substantially decrease, then they could incur heavy costs for waste disposal if alternative uses are not found.

"Currently, all the choice white grease and lard products are being sold at a price higher than the per gallon cost of fuel oil," said Mark W. Badger, director of the analytical research group of The Energy Institute. "It would not be profitable to burn lard now, but Hatfield is looking toward the future."

The researchers, working closely with Hatfield and John Larsen of Lehigh University, and supported by the Ben Franklin Partnership of the Commonwealth of Pennsylvania, compared the combustion properties of semi-finished lard and finished lard to No. 6 fuel oil. Hatfield currently has three boilers operating on Nos. 4 and 6 fuel oil in their main processing plant.

Pig fat contains essentially no sulfur or sulfur compounds and so produces no sulfur dioxide when burned. The study showed that both pork products produced about one-third the nitrogen oxides produced by No. 6 fuel oil. Because the lards are processed, they produce almost no ash. While pig-derived fuels produce slightly less energy per gallon than No. 6 fuel oil, they are cleaner. The tests were run on a boiler adjusted for No. 6 fuel oil producing slightly more carbon monoxide from the pig-derived fuels, but this could be eliminated with proper adjustments. The same fuel-handling system was used with all fuels.

"Although lard and choice white grease are semi-solid at room temperature, this poses no problem because typically, No. 6 fuel oil is heated before burning," said Miller. "We preheated the oils to 120 degrees Fahrenheit and the lards and grease became nicely liquid."

In the processing plant, the edible and inedible fats are processed separately. The inedible fat is rendered and becomes choice white grease. The edible fat goes from the cutting room floor to the melt tank, is heated, centrifuged to break it down and liquefied in a heat exchanger to remove the solids. This produces semi-finished lard, which is as good for fuel as finished lard. The extra expense of finishing the lard by putting it through a separator that removes small insoluble solids and some of the water would be unnecessary should it be used as a boiler fuel.

"Production at the Hatfield plant produces almost nothing as waste," said Miller. "If the current demographics of lard consumers changes, these products make very good fuel.

Working lowers math and science
test scores for eighth-graders

By A'ndrea Elyse Messer
Public Information

Even traditional student jobs like mowing the lawn, babysitting or delivering newspapers may lower math and science scores, according to researchers. Working outside school affects not only U.S. children, but children worldwide.

"Boys, and to a lesser extent girls, show substantial negative effects on math and science achievement associated with after-school employment, even after controlling for family background effects," said David Post, associate professor of education.

Post and Suet-ling Pong, associate professor of education, looked at the National Educational Longitudinal Study (NELS), a 1988 random sample of eighth-graders across the U.S. that followed students through high school. NELS collected data on students' families, in school and after-school activities and tracked their academic progress.

"For boys, clear evidence exists that working during eighth grade has detrimental effects on achievement and on learning math and science in the 10th grade. The evidence for girls is less dramatic, but still significant."

Many jobs give kids little else than hourly wages as they operate fast-food cash registers having coded keys rather than old-fashioned numerals and not requiring even the rudiment of arithmetic.

The researchers also looked at the U.S. eighth-grade data in the Third International Mathematics and Science Study (TIMSS) and found very similar results in the U.S. data. They then used the data to see if the effect occurred universally.

"Those countries where students more often worked for pay had lower overall scores than those where eighth-grade students do not work outside school," said Post. "This was even significant for girls in those countries where girls work outside the house."

Child welfare advocates in many countries spend enormous energy just trying to get kids into school and to pass compulsory laws requiring universal education, said Post.

"However, requiring children to attend school does not decrease the need for these children to work," he said.

Because of this, the researchers suggest that ultimately, child welfare advocates need to reform child labor laws as well as provide the opportunity for education.