The Portland Cement Association (PCA) hosted a press conference at Greenbuild 2008 to issue a reminder that the cement industry remains a critical consumer of scrap tires.
A study by the PCA has identified 48 portland cement manufacturing plants in the United States that are permitted to use tire-derived fuels (TDF) as an energy source.
That number has climbed steadily from TDF’s pioneering days of the late 1980s,when fewer than five cement plants used TDF.
The 48 plants identified are scattered in 21 different states and belong to a variety of cement manufacturers, including multi-national producers such as Holcim, Lafarge and CEMEX. Combined they are estimated to consume as many as 58 million scrap tires each year.
Provided there are enough scrap tires available, the use of TDF may still have a little room to grow. “Additional U.S. plants have expressed interest in obtaining a permit or have received a permit but have not begun utilizing scrap tires as a fuel,” notes the PCA in a summary of its study. Reasons for delays can include state regulatory review as well as concerns about regional TDF availability.
The PCA also studied the emissions effects of TDF plants and found differences between using TDF or using traditional fossil fuels that favored TDF. “Dioxin-furan emission tests results indicated that kilns firing TDF had emissions approximately one-third of those kilns firing conventional fuels—this difference was statistically significantly,” says the PCA summary.
PCA researcher Tyrone Wilson says the 2008 study of 31 cement kilns “confirmed previous studies” regarding the lack of any adverse effects to the use of TDF. According to Wilson, in addition to cutting dioxin emissions, the use of TDF was also found to reduce particulate matter emissions by 35 percent. “This study shows TDF use shows no adverse effect on emissions,” Wilson remarked.
The Greenbuild International Conference and Expo took place Nov. 18-21 in Boston.