The aim of the GreenCarbon project is to demonstrate the material recycling of CO2 into bio-based carbon fiber composites. These are polymers and carbon fiber-based lightweight materials that can be used in the aviation and automotive industries. IGB researchers have succeeded in developing a process that uses catalysis to convert biogenic glycerin into acrylonitrile, the key starting material for carbon fiber production.
Carbon fiber reinforced plastic (CFRP), consisting of a matrix material (duroplast, e.g., epoxy resin, or thermoplastic, e.g., PPS) and the reinforcing fiber (preferably carbon fiber), is a particularly suitable lightweight material for aircraft and automotive construction. For these technical applications, high-quality carbon fibers and the polymer binder (duroplast or thermoplastic) can currently only be obtained from petrochemical processes. In addition, carbon fiber production is energy- and cost-intensive, which is also reflected in the CO2 footprint of the overall process and the cost of this material.
The aim of GreenCarbon is to produce CO2-based carbon fibers and CFRP from algae and to evaluate their performance and application possibilities in the aircraft, automotive, and construction industries in order to shift lightweight construction materials toward a climate-neutral, renewable raw material with a significant impact on its fields of application.
The Green Carbon Project is concerned with the practical demonstration of the material recycling of CO2 into bio-based carbon fiber composites. Due to their rapid growth, the greenhouse gas CO2 can be actively stored in microalgae in the form of biomass. The CO2 is bound in the form of sugars (e.g., glucose), which the cells need to build their cell walls. These sugars are to be released by enzymatic hydrolysis and used for the supply and production of lipids by means of unconventional oil-forming yeasts.
The lipids produced by yeast serve as starting materials for various synergistic, chemical, and biotechnological processes. On the one hand, the chemoenzymatic conversion of lipids into bio-based thermosets is being pursued. On the other hand, the yeast oils are split into glycerin and free fatty acids. The glycerin is converted into carbon fibers using established methods. The free fatty acids are enzymatically converted into two different products. In the first case, unsaturated fatty acids in particular are chemically and enzymatically refined into bio-based thermoplastics. In the second case, enzymatic modification of the fatty acids yields high-quality additives for the lubricant sector.
In the further course of the project, the thermosets and thermoplastics will be combined with the sustainable carbon fibers to form corresponding composites, which will be tested for use in aircraft and automotive construction. The development of the various process platforms will be accompanied by a techno-economic and life cycle analysis.
GreenCarbon – Conversion of CO2 into polymers and carbon fiber-based lightweight construction materials for the aviation, automotive, and construction industries through synergies between chemistry and biotechnology
July 2019 – June 2022
We would like to thank the German Federal Ministry of Education and Research (BMBF) for funding the “GreenCarbon“ project, promotional reference 03SF0577A.
Fraunhofer Institute for Interfacial Engineering and Biotechnology IGB