CEMEX fuel system up and running

Published 12:00 am Wednesday, October 12, 2005

DEMOPOLIS-CEMEX of Demopolis has implemented a new system that is both energy efficient and environmentally friendly according to company officials. For several months the company has discussed plans for putting a system in place to use tire-derived fuels.

CEMEX Plant Manager John Laney came before the Marengo County Commission to announce the system is in place.

“We came here several months ago to ask your support to put in a tire-derived fuel system at our plant in Demopolis,” Laney said. “I just wanted to report that we have completed that and passed all our environmental tests and we were very successful in getting ready.”

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It is estimated about 290 million tires are discarded in the U.S. every year (roughly one per person). Nearly 45 percent of these scrap tires (130 million) are used as “Tire-Derived Fuel” (TDF), which often involves burning the tires alongside conventional fuels like coal.

Tire manufacturers, Tire-Derived Fuel producers and TDF users (burners) and government agencies promote burning TDF as a solution to the dire problem of waste tires. Laney said CEMEX would like to work with the commission to help dispose of scrap tires around the county.

“Now that we have it up and running should the county desire it, we would be more than happy to accept a trailer load of tires if you picked them up from the community,” Laney said. “These are not tires from private businesses. These are things that would help the county if you wanted to pick them up. We would be glad to get this program started.”

Tires can be used as fuel either in shredded form or whole, depending on the type of combustion device. Scrap tires are typically used as a supplement to traditional fuels such as coal or wood. Generally, tires need to be reduced in size to fit in most combustion units. According to the Environmental Protection Agency There are several advantages to using tires as fuel. Tires produce the same amount of energy as oil and 25 percent more energy than coal.

The ash residues from TDF may contain lower heavy metals content than some coals. This results in lower Nox emissions when compared to many U.S. coals, particularly the high-sulfur coals.

The Environmental Protection Agency supports the highest and best practical use of scrap tires in order of preference: reduce, reuse, recycle, waste-to-energy, and disposal in an appropriate facility.

Disposal of scrap tires in tire piles is not an acceptable management practice because of the risks posed by tire fires, and because tire piles can provide habitats for disease vectors, such as mosquitoes.

Tire-Derived Fuels have become especially useful in the cement industry. About 53 million tires per year are consumed as fuel in US cement kilns. The cement industry burns scrap tires as fuel in kilns used to make clinker-a primary component of Portland cement. A cement kiln is basically a large furnace in which limestone, clay, and shale are heated at extreme temperatures and a chemical reaction transforms them into clinker. Clinker is ground together with gypsum to form Portland cement.

Laney said their new system is up and running at a very good percentage.

“We are online now,” Laney said. “We are burning 15 percent of our fuel as tire fuel instead of petroleum coke. At this point we don’t anticipate that changing because of the balance in which we use the fuels.”

Currently, Laney said the company receives tires through a contract.

“Right now we are contracted with a company where they bring us the tires,” Laney said. “A majority of the tires they bring to us come from tire manufacturing plants. Some of them look like brand new tires, but they are rejects. Instead of having to take these tires to landfills they bring them to us.”

The tires are transported to the plant in an 18-wheeler and a device is used to dump the trailer. One of the few requirements for the tires is they can’t have rims.

Laney said they were very pleased to give the system and agreement in place because it allows them to use a renewable fuel source.