OCR Text |
Show with needed energy. Some areas are running out of space available for disposal. Soil temperature and moisture changes result in buried tires "wiggling" to the surface and becoming environmental hazards. Voids in the tires provide habitats for mosquitos, rats, and other vermin. A fire in a tire dump is extremely difficult to put out, and the dense smoke, particulates, and pungent odor are objectionable. With regard to impact on existing industries, there seems to be little justification for shredded tire applications, except in some isolated cases. Retreading should be practiced to conserve resources; nevertheless, after the natural life of a retreaded tire has been fully realized, a method of disposal becomes a necessity. From an overall viewpoint, physical disposal appears to be a transient solution. In the long run, they do little to alleviate the ultimate problem of tire disposal. Whole tires are bulky to handle, hard and energy-consuming to shred, and the useful applications too limited. Except for retreading, there seem to be no physical applications which deserve special consideration. Economic and environmental acceptability factors make this disposal method a doubtful choice. Chemical Applications Chemical reclamation of scrap tire rubber is technically feasible but has encountered problems in all the criteria areas reviewed. It is not the most attractive solution. However, if these problems are not overcome, the tire rubber reclamation industry will remain stagnant. A new impetus in tire rubber reclamation is badly needed. Pyrolysis Pyrolysis offers a route for recovering some of the petroleum based hydrocarbon gases and liquids, and carbon black. Pyrolysis can meet all the criteria posed, but since the products of tire pyrolysis are fuel grade at best, conversion of the tire's chemical energy into heat by direct combustion seems more efficient and practical. From the energy conservationist's point of view, unless pyrolysis can produce something better, direct combustion of tires for heat power generation seems more attractive. Incineration In the search for solutions to tire incineration problems, it should be possible to find existing feasible solutions, and to modify these solutions to meet the problem. Industrial fluidized-bed combustion has been widely used in the processing industry. FBC has found applications in many areas. Among them are the following: o Cracking catalyst regeneration by burning off the carbon deposit on spent cracking catalysts. 11-10 |