However, according to Pilpel, by approaching recycling that way, the committee was left with a tough question: How can you make the materials attractive to an end user? The answer, according to ISRI, was to look at energy conversion as the baseline technology of recycling. That means if the supply chain can’t find value in the glass fiber itself, perhaps businesses can sell the fuel byproduct that comes from it instead. “We believe we can gain more energy out of that process than competitive technologies and competitive materials,” says Pilpel. “There’s a place where we can gain some dollars in terms of selling [the byproduct] as a fuel.”
Since beginning the project, Pilpel says that the process has made significant progress. “The technology looks very promising.” says Pilpel. “The second phase would be to … do some validation of the process at a real pilot plant which is available today. This will help substantiate the business case. The third phase is to bring the technology to make this an enterprise level – commercialize this.”
Currently, the most common form of composite recycling is pyrolysis, during which the polymer matrix of the scrap CFRP decomposes under air exclusion and typically at a temperature of 500 to 600 C. The alternative that other researchers prefer is solvolysis, which reclaims fibers by splitting a solvent at a much lower temperature. While proponents of solvolysis claim pyrolysis compromises the overall quality of the end product, according to the Fraunhofer Institute for Chemical Technology (ICT), pyrolysis is currently considered to be the only process for recycling CFRP that is available on an industrial scale.
One notable example of the industry’s investment in pyrolysis is Toray Industries, which last year signed a deal with Toyota Tsusho Corporation to build a pilot plant that uses gases from the pyrolysis process as an energy source for the recycling of carbon fiber. Toyota believes this could lead to a big reduction in the overall energy consumption of the process.
Another company whose advancements in pyrolysis have caught the industry’s attention is Coseley, U.K.-based ELG Carbon Fibre. As ELG’s Managing Director Frazer Barnes explains, 35 percent of the materials ELG recycles come from dry waste forms, another 35 percent is laminate material and 30 percent is uncured prepreg. The process, Barnes adds, can be used to make non-woven mats, milled fibers, or carbon fiber reinforced thermoplastic (CFRT) pellets for injection molding or chopped fibers.