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A vast majority of the energy used in carbon fiber manufacturing is consumed by a series of furnaces and ovens through which the PAN fibers pass as they are oxidized and carbonized to become carbon fibers. (Click here for more on how carbon fiber is made<\/a>.)<\/p>\n\n\n\n Reducing energy consumption<\/strong>, as would be expected, revolves around sourcing energy from renewable resources<\/strong>, including hydro, solar and wind. This is the relatively low-hanging fruit of carbon fiber decarbonization. There are also technologies aimed at reducing the process time, such as rapid oxidation developed by Deakin University (Geelong, Australia), licensed by LeMond Carbon (Knoxville, Tenn., U.S.) and audited by Bureau Veritas (BV, Paris, France) in 2019<\/a>, that have demonstrated a 70% reduction in energy required per kilogram of output fiber. However, such technologies have yet to be commercialized.<\/p>\n\n\n\n Reducing the carbon footprint of the precursor is much more challenging and generally follows one of two paths<\/strong>. The first path is to develop a new class of precursor from a non-PAN, bio-based source. Lignin, a cellulose byproduct of papermaking, has been the primary focus of this effort, but to date has not been able to produce carbon fibers with mechanical properties on par with those derived from PAN.<\/p>\n\n\n\n The second path is to develop PAN itself from bio-based sources \u2014 that is, a bio-based PAN chemically identical to petroleum-based PAN and thus a potential drop-in replacement in the carbon fiber manufacturing process. From a materials property perspective, this path is preferable for obvious reasons, but the challenge is one of cost. Is it possible for a bio-based PAN to be cost-competitive with petroleum based PAN?<\/strong><\/p>\n\n\n\n In 2019, CW<\/em> reported on a research program at Southern Research<\/a> (Birmingham, Ala., U.S.), to develop a cost-effective process for the manufacture of ACN from non-food carbohydrates<\/a>. The program revolved around the use of xylose and glucose (aka C5<\/sub>, C6<\/sub> sugars) harvested from wood-based biomass and refined via hydrolysis. The process involves passing the sugar feedstock through a series of three catalysts, with each catalyst producing an intermediate material and, in the process, generating a chemical byproduct:<\/p>\n\n\n\n As part of its research with bio-based ACN, Southern Research conducted a life cycle assessment (LCA), comparing biomass-to-ACN manufacture to petroleum-to-ACN manufacture. Results said bio-based ACN manufacture offers a carbon footprint of -1.57<\/em> pounds equivalent CO2<\/sub> per pound of finished product, compared to 3.5 pounds equivalent CO2<\/sub> per pound of finished product for petroleum-based ACN manufacture. In short, the bio-based feedstock allows for a process that conserves<\/em> carbon emissions.<\/strong><\/p>\n\n\n\n Regarding cost, Southern Research\u2019s process is sensitive to the purity of the sugars feedstock, and the higher the feedstock quality, the more expensive it is. When CW<\/em> last spoke to Southern Research, it was getting ready to commission a small-scale production plant and looking for carbon fiber manufacturers willing to assess the quality of its ACN.<\/p>\n\n\n\n A lot has happened in three years. Notably, the ACN production process<\/strong> Southern Research developed has been licensed by Trillium Renewable Chemicals<\/a><\/strong> (Knoxville, Tenn., U.S.), which is commercializing it for production of ACN and acetonitrile.<\/p>\n\n\n\n Corey Tyree, CEO of Trillium, says the company, still in startup mode, completed its seed raise ($3 million) in early 2021 and then constructed a glycerol-to-ACN pilot plant in Charleston, W.V., U.S. This facility applies the core technology \u2014 dehydration and ammoxidation \u2014 established at Southern Research, with feedstock primarily from plant-based glycerol derived from soybean oil. Tyree notes that Trillium\u2019s process also accepts glycerol from rapeseed oil, which is common in Europe, or palm oil, which is common in Asia.<\/p>\n\n\n\n The pilot plant provided a platform to help Trillium optimize its ACN manufacturing process<\/strong> in anticipation of the company\u2019s next evolutionary step: Construction of a market-scale demonstration plant somewhere in the U.S. This facility, says Tyree, could break ground before the end of 2023 and begin production by mid-2024. Its capacity will be 25 kilograms\/week, with funding provided by a $10.6 million Series A financing round in late 2022.<\/p>\n\n\n\n Ultimately, Tyree says, once its ACN manufacturing process is fully derisked, Trillium expects to construct multiple full-scale production plants around the world.<\/strong><\/p>\n\n\n\n Although Trillium\u2019s ACN, marketed as Bio-ACN, can be targeted to a variety of industries and applications, Tyree says customer and market signals will determine the direction the company follows. And so far, the strongest signals are coming from the carbon fiber manufacturing industry.<\/p>\n\n\n\n In early 2022, Trillium and carbon fiber manufacturer Solvay Composite Materials<\/a> (Alpharetta, Ga., U.S.) signed a letter of intent (LOI) to develop a supply chain for Bio-ACN<\/a>. Under this agreement, Solvay, in 2023, will conduct an analysis of Trillium\u2019s Bio-ACN to verify its chemistry and composition. This will be followed, in 2024, by Solvay conducting an LCA of the Bio-ACN.<\/p>\n\n\n\n <\/a><\/p>\n\n\n\nThe genesis of bio-based PAN<\/strong><\/h3>\n\n\n\n
Bio-based ACN goes commercial<\/strong><\/h3>\n\n\n\n
Carbon fiber supply chain interest<\/strong><\/h3>\n\n\n\n
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