How Lignin is Converted into Carbon Fibers
Key Steps:
- Lignin Extraction & Fractionation
- Sourced from kraft pulping, organosolv, or soda processes.
- Purified and fractionated to obtain thermoplastic lignin fractions with desirable softening and flow properties.
- Melt Spinning
- Lignin is melt-spun into fibers (pure or blended with PAN/polyethylene oxide).
- Requires tuning of molecular weight and viscosity.
- Stabilization (Oxidative Thermosetting)
- Fibers are oxidized at ~200–250 °C to crosslink lignin and prevent melting during carbonization.
- Carbonization
- Fibers are pyrolyzed in an inert atmosphere at 800–1600 °C to form carbon-rich filaments with >90% carbon content.
- Post-treatment
- Surface modification and sizing for compatibility with polymer matrices in composite manufacturing.
Feedstocks: Kraft lignin, soda lignin, organosolv lignin, hydrolysis lignin (from biorefineries)
Case Study: ORNL (USA) – Lignin Fiber Pilot Line
Highlights:
- ORNL developed a pilot-scale lignin carbon fiber production line to reduce cost and environmental impact.
- Used low-sulfur hardwood lignin from biorefineries.
- Demonstrated blends of lignin with PAN and 100% lignin fiber spinning.
Timeline & Outcome:
- 2014: First lignin-derived carbon fibers with tensile strength ~500 MPa.
- 2016–2018: Process optimization with melt-blend spinning and surface treatment.
- 2020: Integrated into BMW’s R&D for vehicle lightweighting.
- 2023: Partnerships expanded with Kureha (Japan) and Domtar for feedstock sourcing and automotive testing.
Global Startups and Companies in Lignin-Based Carbon Fibers
- LignoTech (Norway/USA) – Produces high-purity lignin; partnered with carbon fiber research labs.
- Domtar (USA) – Supplies lignin from pulp mills for carbon fiber development.
- Stora Enso (Finland) – Developed Lineo® lignin, targeting carbon fiber applications.
- Melodea (Israel) – Specializes in lignin and cellulose nanomaterials for composites.
- RenCom (Sweden) – Focuses on lignin thermoplastics and fibers.
India’s Position
- India has large lignin availability (~18 million tons/year) from sugar, pulp, and biomass sectors.
- CSIR-CLRI, BHEL, and IIT Bombay have worked on lignin valorization and fiber formation.
- No commercial lignin carbon fiber units exist yet.
- Initiatives like “National Mission on Bioeconomy” and NTPC’s biomass use programs can synergize to develop this sector.
- HPCL-Mittal Energy and Godavari Biorefineries can be future lignin suppliers.
Commercialization Outlook
Market & Demand
- Global carbon fiber market: ~$5.6 billion (2024), expected to grow to $9+ billion by 2030.
- Applications:
- Automotive lightweighting
- Wind turbine blades
- Aerospace structures
- Sporting goods & defense composites
Key Drivers
- Demand for lightweight, high-strength materials.
- Interest in sustainable, low-cost precursors vs. expensive PAN.
- Lignin is abundant, underutilized, and has high carbon yield (~50%).
Challenges to Address
- Inconsistent lignin quality and purity between sources.
- Mechanical properties (tensile strength, modulus) currently lower than PAN-based carbon fibers.
- Stabilization and carbonization steps are energy-intensive.
- Lack of industrial spinning infrastructure in lignin-rich regions like India.
- Need for standardized lignin grades for fiber performance predictability.
Progress Indicators
- 2014: ORNL demonstrates lignin-based fiber pilot line.
- 2016–2019: Partnerships with BMW and Ford for vehicle testing.
- 2020–2022: Domtar and Stora Enso scale lignin fractionation for composites.
- 2023: European Horizon projects fund lignin fiber composites in aerospace.
- 2024: Stora Enso’s Lineo lignin trialed for carbon fiber in Nordic EVs.
- India: IIT Bombay and CLRI publish scalable extraction-purification methods for soda lignin (2023).
TRL 6–7 globally, with pilot and demonstration-scale systems validating performance in automotive and wind sectors. In India, TRL remains at 4–5, with ongoing R&D but no industrial integration yet.
Conclusion
Lignin-based carbon fibers represent a promising breakthrough in low-cost, bio-derived composites, aligning with the goals of sustainable mobility and circular materials. Institutions like ORNL, Stora Enso, and Domtar have demonstrated technical viability, while global automotive and wind sectors drive demand for greener alternatives. India’s abundant lignin resources, combined with growing interest in lightweight electric vehicles and renewable energy, create a strong foundation. For meaningful adoption, India needs to scale pilot facilities, standardize lignin streams, and attract cross-sector collaboration. As markets shift toward bio-advanced materials, lignin carbon fibers are poised to play a key role in the next generation of eco-friendly composites.
Wish to have bio-innovations industry or market research support from specialists for climate & environment? Talk to BioBiz team – Call Muthu at +91-9952910083 or send a note to ask@biobiz.in
Expert Consulting Assistance for Indian Bioenergy & Biomaterials
Talk to BioBiz
Call Muthu – 9952910083
Email – ask@biobiz.in
