ASTM D6700-19 covers and provides guidance for the material recovery of scrap tires for their fuel value. The conversion of a whole scrap tire into a chipped formed for use as a fuel produces a product called tire-derived fuel (TDF). This recovery guide has moved from a pioneering concept in the early 1980s to a proven and continuous use in the United States with industrial and utility applications.
6.7 TDF in a size range of 2-in.(5.08 cm)minus is normally compatible with wood fuel and stoker coal in conveying to conventional stoker boilers, thus allowing for easy introduction onto an existing feeding system.Large pieces of rubber may be rejected or sent to a hammer mill for further size reduction via screening systems used to reject oversized coal or wood fuel, if such systems are in place. Oversized pieces should be avoided under these circumstances due to a hammer mills or coal crushers difficulty in processing tire chips.
6.8 A storage pile of TDF can mimic coal in appearance from a distance. but does not create dusting concerns when left in the open unprotected. TDF storage piles, if of sufficient size, may experience heating problems similar to coal piles. Storage management should be similar to that of coal to preclude heating problems.