New Research Seeks A Way to Recycle & Reuse Carbon Fiber
While “put the pedal to the metal” has a nice ring to it, increasingly, when we drive – or fly – there is a rapidly decreasing amount of actual metal involved. If you have flown on a Boeing 787 Dreamliner, you have flown on a plane made of 50 percent carbon fiber. If you have driven a Ford GT, you have also rolled some carbon fiber down the highway.
Carbon fiber isn’t a new material – Thomas Edison actually tinkered with it as a filament for a light bulb – but in an era of rising fuel costs and carbon footprint awareness, it’s getting more attention as a building material for anything that could stand to be a bit lighter. The properties of carbon fiber and its composites – high tensile strength, chemical and heat resistance, low thermal expansion and rigidity – make the material ideal for aerospace and automotive uses. Aircraft or automobiles produced with a high percentage of carbon fiber is both durable and fuel efficient.
Unfortunately, it’s not cheap. About a decade ago, carbon fiber typically cost about $150 a pound. Today, it’s about $10 a pound. (Keep in mind that steel costs less than a dollar per pound.) Industry analysts say that for carbon fiber to find its way into more than high-end and concept cars or flagship aircraft, the price will need to come down to a point below $5 per pound.
So how to accomplish this? For starters, manufacturing processes for carbon fiber need to become more widespread and efficient. Another reason carbon fiber is problematic is that it’s difficult to recycle. Carbon fiber can’t be melted down, which complicates the end of life process. Recycled carbon fiber isn’t as strong as virgin material (unlike in the case of recycled steel), which means that carbon fiber materials recycled from vehicles aren’t suited for building more vehicles, according to the Web site How Stuff Works.
At least two companies are hoping to change this. Boeing and the BMW Group announced last week that they plan to share carbon fiber manufacturing process simulations and ideas for manufacturing automation. The partnership is expected to develop less expensive production methods and focus on carbon fiber recycling both during production (excess byproduct) and at the end of life for the products.
Both companies are heavily invested in carbon fiber. Boeing uses the material extensively in its new 787 Dreamliner: fully half the plane is made from the composite. Germany’s BMW has been using carbon fiber in some of its cars for more than 10 years, and next year, plans to begin selling its carbon fiber-bodied i3 and i8 models. (Only a handful of other cars contain carbon fiber at this point, including the BMW M6, the Audi R8, the Chevrolet Corvette ZR1 and the Ford GT.)
Until not very long ago, composite materials from planes and cars were generally junked in landfills or burned. As the U.S. and Europe tighten environmental regulations, this is becoming a less viable option. In 2004, most EU member states made it illegal to dump composites into landfills, which has presented major problems for airlines, aircraft and auto manufacturers. EU law drawn up in 2000 states that 95 percent of each vehicle manufactured after January 2015 must be reused or recovered.
For most industries, recycling has four steps: collection, identification and separation, reclamation and remarketing of the resulting materials. Recycling isn’t particularly financially viable if the value of the recycled materials is less than the cost of the recycling process, which is often the case for composites today.
According to Composite World, recent technological advancement in carbon recycling has made the process somewhat more practical, but reclaimed fibers still have few real uses, which is why the partnership between Boeing and BMW is so noteworthy.
“Through this cooperation, we can merge know-how between our industries in the field of sustainable production solutions,” said Herbert Diess, a member of the BMW board for development, at the time the partnership between the two companies was announced.
As part of its SGL Automotive Carbon Fibers LLC joint venture, BMW has built a new carbon fiber plant in Moses Lake, Wash. The plant’s goal is to automate production of ultra-light carbon fiber reinforced plastics for use in future vehicle concepts, most notably BMW’s upcoming i3 and i8 models.
On the airliner side, Boeing isn’t the first aircraft manufacturer to spend brainpower and money on carbon fiber recycling. Airbus is leading an EU sustainability project called the “Process for Advanced Management of End of Life of Aircraft (PAMELA).” The $3.2 million project, begun in 2006, was put in place to establish best practices for coping with aircraft at the end of their useful lives, including what to do with the large amounts of carbon fiber recovered from junked planes. Thus far, PAMELA’s primary accomplishment has been developing a process for grinding composites into granules for use as filler materials in asphalt. Reclaimed short fibers are used to reinforce sheet molding compound and bulk molding compound.
In 2008, Milled Carbon set up Recycled Carbon Fibre Ltd, the world’s first commercial-scale recycled carbon fiber operation. In September 2011, Recycled Carbon Fibre Ltd was purchased by Germany’s ELG Haniel, a materials recycling company, and became ELG Carbon Fibre Ltd. ELG Carbon Fibre operates a furnace that has the capacity to process about 2,000 tons of carbon fiber waste each year. The company offers a product line of recycled carbon fiber materials that can be used as raw materials in other industries, though still mostly as fillers.
The goal of most next-generation recycling programs for carbon fiber is to further a complex chemical process known as “solvolysis” that can separate carbon fiber from resin, allowing the fibers to be realigned for a new vehicle or aircraft use and not simply to bulk up road building materials.
Carbon fiber recycling is one of the processes a group known as the Aircraft Fleet Recycling Association (AFRA) hopes to advance. The Association is an international, Washington DC-based collection of corporations and research groups that pushes environmental best practice and regulatory compliance in aircraft disassembly and salvage. Members include prominent aircraft manufacturers, university research labs, materials reclaiming and recycling companies and aircraft disassembly companies.
The need is becoming more urgent. The AFRA estimates that more than 12,000 aircraft will reach the end of their useful lives in the next 20 years. The traditional practice of parking old aircraft in the desert and allowing them to quietly disintegrate will no longer be an option soon. As more carbon fiber-based cars enter the market, the automotive industry needs to have a viable plan for dealing with these cars at the end of their useful lives. Partnerships such as the one between Boeing and BMW will hopefully find a market-driven process for reusing a material that is finding an increasing number of applications in industry today.