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Approximately 5 billion lbs of carpet will be removed from buildings in the US each year for the foreseeable future, according to a report by Georgia Tech Research Corporation.
Carpet As An Alternative Fuel in Cement Kilns, PVC tiles are, at the time of the report, handled through a recycling system run by Interface or Tandus, so they were excluded from the study, according to the final report. Broadloom, in contrast, “is not recycled in significant volumes compared to its sales” and is the subject of the report. The face of that carpet contains plastic that can be reused, but it is held in place by a latex cross-linked polymer heavily loaded with calcium carbonate. The report states that this backing has almost no value as a recycled material. Researchers then burnt carpet as fuel at Lehigh Cement’s kiln in Evansville, Pennsylvania. Carpet proved technically suitable, yet the report concludes that the economic barriers were too high. Carpet tile is typically made for the commercial market and has a heavier backing, often PVC. Broadloom comes with two backing types, an SB latex and a polyurethane foam back, and with two face constructions: level loop and tufted.
The report records that carpet was burnt at rates approximating 10–15% of the fuel load, at about 2–2.5 tons per hour, and that this did not negatively impact the kiln’s emissions. NOx and SO2 emissions were below the allowed limits for both coal and carpet co-firing, although SO2 appeared higher for carpet, according to Table 9.
The report concludes that “carpet was technically a suitable fuel.” The project’s research question was whether carpet could be used as a fuel in a cement kiln. The trial took place at Lehigh Cement’s long dry kiln at Evansville, Pennsylvania.