TIRE AND TDF USE IN PORTLAND CEMENT KILNS

The portland cement production process is extremely energy intensive (from 4 to 6 million Btu s (MMBtu s) are required to make a ton of product) therefore, alternative and cost-effective fuel options are of great interest. Waste tires have been tried as a supplemental fuel in veil over 30 cement kilns and in at least one rotary lime manufacturing kiln. Currently, tires are in use, either on a trial or permanent basis, in 11 cement kilns and one lime kiln. 

Cement plants attract favorable power rates because the process is so energy intensive TDF cost per Btu is thus less of a savings. Second, cement kilns can accommodate many alternate fuels,1 such that regional availability and price for these may affect the marginal savings of TDF. For example, on the Southeast Gulf coast, petroleum coke is 

This chapter describes the use of whole tires and TDF in the cement industry in five sections. First, an industry description is provided. Second, the cement production process is described, including traditional fuel use and use of both whole tires and TDF as supplemental fuel. Third, air pollution implications are discussed in detail, including emissions, control techniques, and control effectiveness. Fourth, other environmental and energy impacts are evaluated. Last, cost considerations of tire use are described. 

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Currently, in the U.S., a few boilers operate by burning solely whole tires or TDF, all in the electric utility industry. These are discussed in Chapter 3, Dedicated Tires-to-Energy Facilities. Chapter 4, Tire and TDF Use in Portland Cement Kilns, discusses in more detail the use of TDF in lime and cement kilns. 

When whole tires are used as supplemental fuel in cement manufacture, they generally enter the process at the upper feed end of the kiln. Depending on the specific process flow at a facility, TDF can be added at the feed end, at the lower (firing) end, or in a raw feed preheater/precalciner that is located before the raw feed entrance. These options are described in more detail in Chapter 4, Tire and TDF Use in Portland Cement Kilns. 

TDF in a lime kiln, and is included in Chapter 4, Tire and TDF Use in Portland Cement Kilns. 

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