French company Simav is developing a new thermal process, thermolysis, to recycle the carbon fiber contained in composite materials and claims that its process yields a higher-quality recycled fiber than the current one.
“Airbus is testing a prototype of our recycling machine in Toulouse and we plan to install a production-standard machine there late this year or early in 2009,” Simav CEO Ghassan Khouri told AIN.
Simav engineers have figured out how to recycle the composite fiber at a lower temperature. The new process works at 840 degrees F (450 degrees C), versus 2,000 degrees F (1,100 degrees C) for pyrolysis. Khouri said the recycled fiber retains “90 to 95 percent of its original qualities” because there is less damage to the carbon fiber.
There are several other benefits of the new process. First, it yields fewer polluting byproducts than pyrolysis. For example, while pyrolysis produces dioxin, thermolysis does not. The new process also uses less energy than the original. Once started, the machinery uses 15 kilowatts of electricity and eight gallons of diesel fuel per hour. In addition, the new process uses about 16 to 21 gallons of water per hour, a relatively small amount. According to Khouri, the process is much less expensive than pyrolysis.
During thermolysis, most of the resin is vaporized, with about 3 to 5 percent remaining around the fibers. Khouri claimed this is not a shortcoming. So far, recycled fiber use has been limited to non-structural components such as seats. Simav engineers believe, however, that it is suitable for structural use and are endeavoring to prove that recycled fibers are up to the task of being turned into airframes.