The US Department of Energy (DOE) will award (DE-FOA-0000996) up to $12 million in funding to advance the development of a cost-competitive pathway to produce high-performance carbon fiber for vehicle lightweighting from renewable non-food biomass. Reducing a vehicle’s weight by just 10% can improve fuel economy by 6% to 8%.
Carbon fiber composites are lightweight, yet strong, materials that can greatly improve vehicle fuel efficiency when incorporated into structural and non-structural components. Carbon fibers are polymers that are typically made from petroleum and natural gas feedstocks (propylene and ammonia, respectively) that react to form acrylonitrile (ACN) which is then polymerized and spun into polyacrylonitrile (PAN).
The volatility of the raw material prices and the energy intensive processes used in the manufacturing contribute to high cost carbon fibers (>$10/lb), which deter widespread use by the automotive industry.
The objectives of the Renewable Carbon Fibers FOA are 1) to identify and to develop a cost-competitive technology pathway to high performance carbon fibers using biomass as a starting raw feedstock and bio-ACN as a target product; and 2) to engage with industrial manufacturers of PAN that will benchmark and validate the bio-ACN with respect to the key technical performance attributes important for manufacturing lightweight automotive structural components.
The goal of the FOA is to enable technologies that can produce bio-ACN at a modeled cost of $1.00/pound or less, thereby to enable the overall manufacturing of carbon fiber at less than or equal to $5.00/lb by 2020 suitable for vehicle structural components.
If the goal is met by a successful project team, and the activities conducted under these awards are properly synergized and coordinated with other complementary activities within the EERE Advanced Manufacturing Office and the Vehicle Technologies Office, then, suggests EERE, the anticipated outcomes are:
Enabling the use of cellulosic sugars or lignin in the production of millions of metric tons of higher value commodity chemicals, such as bio-ACN, thereby avoiding an equivalent amount of fossil fuel derived chemicals and generating more than $57B of new revenue throughout the renewable carbon fiber supply chain; and
Enabling the substantial market penetration of the resulting renewable lightweight carbon fiber to assist in reducing the average weight of passenger cars by 10%, thereby reducing annual petroleum consumption by more than 5 billion gallons in the United States.
The DOE Office of Energy Efficiency and Renewable Energy (EERE) anticipates making awards that range from $6,000,000 to $12,000,000; projects will run up to 40 months.
Background. DOE held a workshop in June 2013 in Detroit to engage external stakeholders in discussing the state-of-technology and performance requirements for automotive carbon fiber materials with respect to PAN and other carbon fiber intermediates, and technology routes to synthesize these intermediates using biomass feedstocks.
The inputs of more than 80 diverse stakeholders with different expertise and representing industry (43%); national laboratory/government (34%); and academia (10%) were gathered and captured in the Renewable Carbon Fiber Workshop Summary Report.
The attendees generally agreed that ACN was likely to be the most near-term carbon fiber monomer to target and the most likely to gain ready market acceptance. However, the cost of production for bio-ACN is expected to exceed that of conventional ACN in the near term as the technologies necessary for the conversion process have only recently been shown under laboratory settings.
In addition, it remains unclear whether bio-ACN can meet the chemical specifications and manufacturability requirements to generate a carbon fiber composite suitable for vehicle structural components, with tensile strength exceeding 250 ksi (kilopounds per square inch) and a Young’s modulus exceeding 25 Msi (megapounds per square inch).
In addition, almost nothing is known about the potential of the new biomanufacturing process to lessen the energy intensity and associated greenhouse gas emissions over the convention carbon fiber manufacturing process when considering the full material life-cycle.
Prior attempts to produce renewable carbon fiber have focused on converting lignin. A half-century of research and development resulted in identifying key parameters for spinning lignin into carbon fibers, including the range of molecular weights and compositions best suited for production. Various methods for producing carbon fibers from lignin have been tested, with melt-blowing of soluble lignin emerging as the favored method. Lignin has also been used to displace a percentage of PAN in conventional carbon fibers, but the resulting material did not meet targets for quality.
The challenges associated with direct conversion of lignin to finished carbon fibers, including meeting structural specifications and developing new manufacturing processes and lines, mean that it could take longer for its commercial potential to be realized than drop-in bio-ACN.
Glycerol is another potential raw material for bio-based acrylonitrile. The indirect ammoxidation of glycerol to acrylonitrile was demonstrated in a tandem reactor where glycerol dehydration formed an acrolein intermediate followed by the ammoxidation of acrolein to acrylonitrile. The resulting acrylonitrile can be polymerized to form polyacrylonitrile (PAN) fibers for subsequent conversion to carbon fiber.
These insights led to the development of the following technical priorities for the DOE renewable carbon fiber effort:
Highly efficient, scalable and integrated process to convert biomass into intermediates that are suitable for further upgrading to bio-ACN;
Highly efficient, scalable and integrated process to convert biomass intermediates into bio-ACN;
Highly effective separations and products recovery processes at each of the material junctions that are able to be integrated with the conversion technologies; and,
Manufacturing process validation of the bio-ACN technical performance attributes as manifested in the final PAN white fiber.
FOA Topic of Interest. There is only one topic area for this FOA: the conversion of raw biomass sugars, algal oils, or lignin to high quality acrylonitrile. The first phase of the project will be focused on establishing the critical functions of the prototype system at bench scale. The second phase of the project will be focused on validating the prototype performance at a larger scale.