ASTM D6700-19 pdf free.Standard Guide for Use of Scrap Tires as Tire-Derived Fuel.
ASTM D6700 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.
1.2 Combustion units engineered to use solid fuels, such as coal or wood, or both, are fairly numerous throughout the U.S. Many of these units are now using TDF even though they were not specifically designed to burn TDF. It is clear that TDF has combustion characteristics similar to other carbon-based solid fuels. Similarities led to pragmatic testing in existing combustion units. Successful testing led to subsequent acceptance of TDF as a supplemental fuel when blended with conventional fuels in existing combustion devices. Changes required to modify appropriate existing combustion units to accommodate TDF range from none to relatively minor. The issues of proper applications and specifications are critical to successful utilization of this alternative energy resource.
1.3 This guide explains TDF’s use when blended and combusted under normal operating conditions with originally specified fuels. Whole-tire combustion for energy recovery is not discussed herein, since whole-tire usage does not require tire processing to a defined fuel specification.
5. Tire-Derived Fuel Analysis — General Description
5.1 TDF is defined as a fuel source derived from the processing of scrap tires into rubber chips with a range in size and metal content. Processing may include shredding. chopping, classification, recycling, granulation. wire/fabric separation, and other technologies. Size normally varies in a range from 1 in. (2.5 cm) to 4 in. (10.2 cm). Metal content ranges from wire free, to relatively wire free, to only bead wire removed. to no wire removed. TDF’s tolerable wire content is determined by a combustion unit’s design considerations. TDF’s wire removal is determined by production process capabilities. Some combustion units such a cement kilns can tolerate all inherent wire, so no removal is necessary. In circumstances where rn’ eflort is made to remove wire, TDF must be cleanly cut with minimal exposed wire protrusion from the chips to facilitate mechanical handling.
8. Sampling and Analysis
8.1 A typical, multiple-use site specification for TDF that currently is fed to many of the power units, alluded to in (he overview as 2 in. (5.08 cm) minus, is identified in Table 3. This size specification also has been successfully applied to pneumatic conveyance into lime and cement kilns while maintaining complete combustion and kiln product quality. Applications in lime kilns are end pr(Nluct quality specific.
8.2 The determination ot TDF size distribution is well defined through the analysis perftrmed via modified Test Method D4749. The analysis to perform for wire content has been developed as follows:
8.2.1 Collect a random No. 5 sample of TDF (see Test Method E873).
8.2.2 Send to a lab with the ability to grind the entire sample into at least 0.25 in. (0.635 cm) particle size. This additional refinement will liberate (separate) remaining inherent wire from rubber particles.
8.2.3 Qualified laboratories will separate wire from rubber magnetically.ASTM D6700-19 pdf free download.