furans, and particulates. Testing did not include baseline (without TDF in the fuel) conditions.21
As seen in Table 4-5, particulate emissions were found to be emitted at a rate of 0.04 lb/ton clinker. In 1981, particulate emissions from the kiln, clinker cooler, and raw mill were estimated to be 0.027 lb/ton clinker burning only coal. When the raw mill was bypassed (i.e., kiln and cooler dust were not recycled), emissions from the kiln and cooler were estimated to be 0.051 lb/ton clinker.21
Test results using CEMS at Southwestern Portland Cement in Victorville, California, showed no increase in particulates, a decrease in NOx, and an increase in CO.16
No information was found that indicated other environmental impacts for the cement industry as a result of using whole tires or TDF. Often, cement dust is ducted back into the kiln, except in cases where the alkali content of the dust would cause a problem for the quality of the finished cement. In those cases, the dust from the fabric filter or ESP is landfilled. This situation does not change with tire use. At Holnam, plant personnel have experimented with briquetting ESP dust.19
Permit conditions were found in several cases that limited the storage and transportation of tires on plant premises,and that mandated safety and emergency procedures and precautions because of the fire hazards.
In one case, the State has limited a cement plant to the sources of its tires. Gifford-Hill in Harleyville, S.C., has a permit condition that the tires must come from a tire dealer, not a landfill or an outside storage facility. This condition was added because the State has had problems with tires contaminated with garbage or were infested with mosquitoes.11
Use of tires or TDF is economical only in relation to other supplemental or waste■fuels in the industry on a regional basis. The kilns most likely to burn TDF are those with preheaters because the introduction of tires into the kiln is more easily accomplished through the preheater (i.e., it is more difficult to feed tires into kilns without a preheater) .
Calaveras, which burns approximately 60 tons per day, purchases 2-inch wire-in TDF for approximately $30 per ton. On a dollar per Btu basis, this is approximately one-half the cost of coal. Calaveras will be installing a whole tire feed system, which will cost about $400,000. (In this system, whole tires will be fed by a conveyor into the exhaust of the kiln.) A tipping fee of between $0.50 and $1.00 per tire for whole tires will be charged by Calaveras. Once the whole tire system is in place, Calaveras estimates that the tire fuel will cost one-tenth or less the cost of coal on a Btu basis.21
At another cement manufacturer, Holnam/Ideal, TDF costs are 34 percent of their coal costs on a dollar per Btu basis. Fuel costs at Holnam/Ideal are approximately 19 percent of their production costs. Of this 19 percent, coal accounts for 50 percent of the cost; coke, 35 percent; and TDF, 15 percent.19
The long residence time and high operating temperatures of cement kilns provide an ideal environment to bum tires as supplemental fuel. Results of several tests conducted on cement kilns while burning tires or TDF indicate the emissions are not adversely affected, but in many cases improve when burning tire.
Costs associated with modifying feed equipment to bum TDF in cement kilns is minor in most cases. Cost savings in fuel cost can be 70 to 90 percent of the cost of the primary fuel, depending on location and governmental incentives.
Overall, burning tires or TDF in cement kilns appear to be em economically satisfactory and environmentally sound way of not only disposing scrap tires, but also reclaiming their fuel value.
1. U.S. Environmental Protection Agency. Market for Scrap Tires. EPA/530—SW—90—074B. September 1991.
2. Portland Cement Association, U.S. and Canadian Portland Cement Industry: Plant Information Summary. December 31, 1990.
3. U.S. Environmental Protection Agency, Office of Air Quality Planning and Standards. Portland Cement Plants—Background Information for Proposed Revisions to Standards. EPA-450/3-85-003a. May 1985.
4. Scrap Tire Fuel for Cement K±lns. Exchange Meeting Summary. Sponsored by U.S. Department of Energy, Office of Industrial Programs. October 2, 1984. Chicago, Illinois. CONF-8410167
5. Ohio Air Quality Development Authority. Air Emissions Associated with the Combustion of Scrap Tires for Energy Recovery. Prepared by: Malcolm Pirnie, Inc. May 1991.
6. Telecon. Russell, D., Pacific Environmental Services, Inc., (PES) with Hale, C., Ash Grove Cement Co. March 1, 1991. Ash Grove's TDF experience.
7. Memorandum from Clark, C., PES, to Michelitsch, D., EPA/ESD/CTC. Summary of Meeting with Scrap Tire Management Council. October 29, 1991.
8. Telecon. Clark, C., PES, with Siemering, W., Calaveras Cement. February 20, 1991. Calaveras' TDF experience.
9. Telecon. Clark, C., PES, with Justice, A., Illinois Department of Energy and Natural Resources. February 19, 1991. TDF use in Illinois.
10. Telecon. Russell, D., PES, with Lauer, C., Florida Crushed Stone, Brookville, Florida. March 15, 1991. TDF experience.
11. Telecon. Russell, D., PES, with Bunn, L., South Carolina Department of Health and Environmental Control. February 14, 1991. South Carolina TDF experience.
12. Amtest. State of Washington, Department of Ecology. Rubber Tire Chip Trial Burn. Holnam Incorporated Industries. Stack Testing and Chemical Analysis. October 15-19, 1990.
13. Telecon. Clark, C., PES, with Hoard, S., Holnam/Ideal Cement, Inc., Seattle, Oregon. March 5, 1991. TDF experience.
14. Telecon. Russell, D., PES, with Allan, G., California Air Resources Board. February 14, 1991. Facilities burning tires or TDF in California.
15. Campbell, Tom. "Cement Maker Plans to Use Tires as Fuel in Botetourt Kiln.N Article in Richmond Times Dispatch. June 6, 1991. p. E-6.
16. Telecon. Clark, C., PES, with Mclver, D., Southdown, Southwestern Portland Cement. February 28, 1991. Southdown's TDF experience.
17. Telecon. Clark, C., PES, with Hilkins, T., Ohio EPA, Air Division. February 28, 1991. TDF use in Ohio.
18. Source Test for Boise Cascade Lime Manufacturing Facility, Walluloa, WA. Prepared for Washington Department of Ecology. Test Date: May 20, 1986.
19. Memorandum from Clark, C., PES, to Michelitsch, D., EPA/ESD/CTC. October 28, 1991. Site Visit — Calaveras Cement Company.
20. Oregon Department of Environmental Quality. Air Contaminant Discharge Permit Application Review Report. Permit Number: 01-0029. Applicaton No.: 12326. Ash Grove Cement West, Inc., Durkee, OR. March 1990.
21. Memorandum from Clark, C., PES, to Michelitsch, D., EPA/ESD/CTC. November 8, 1991. Site Visit — Holnam, Inc./Ideal Cement.
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