SKOKIE, Ill.- Research released by the Portland Cement Association (PCA) supports findings from previous air emission studies conducted by government agencies and engineering firms that indicate that tire-derived fuel (TDF) use in cement kilns does not adversely affect the emissions profile of various air pollutants.

The report emphasizes the environmental benefits of using scrap tires as supplemental fuel in the cement manufacturing process.

Tyrone Wilson, Ph.D., director of regulatory affairs for PCA, said, "This study shows that tires, which pound for pound have a greater fuel value than coal, can also help manufacturers recycle tires without adversely affecting emissions. The nearly 300 million used tires generated by the United States each year can create an environmental nuisance and eyesore. By simply disposing of these tires in landfills or junkyards, society misses an important recycling opportunity: the chance to recover energy and conserve fossil fuel resources,"

The study, conducted by Air Control Techniques, P.C., is based on emission data collected by PCA from 31 cement plants presently firing TDF. The emissions of particulate matter, nitrogen oxides, most metals, dioxin-furans, and sulfur dioxide from kilns firing TDF with conventional fuels were slightly lower than emissions measured from kilns firing only conventional fuels.

The emission levels for carbon monoxide and total hydrocarbons were slightly higher for TDF-firing versus non-TDF firing kilns. None of these differences in emissions were significantly different.

Additionally, cement plants using TDF reduce the amount of coal burned. For each ton of TDF used, the plant reduces the need to use 1.25 tons of coal. This means that less carbon dioxide (CO2) is produced.

Portland cement kilns are especially well-suited for the safe and efficient consumption of the millions of used tires generated each year. Wilson said, "The intense heat of the cement kiln ensures complete destruction of the tires. Because the fire is contained within the kiln under intense heat, there are no visible emissions from the tires such as the heavy black smoke seen in an open-air tire fire."

About PCA
Based in Skokie, Ill., the Portland Cement Association represents cement companies in the United States and Canada. It conducts market development, engineering, research, education, and public affairs programs. More information on PCA programs is available at