Faraday Technology, a U.S. Department of Energy (DOE) Small Business Innovation Research (SBIR) recipient, has developed an energy-efficient method for removing water from cellulosic nanomaterials. This new approach has the potential to make these materials more accessible for a range of industrial applications by making them more economical to transport.
Cellulosic nanomaterials, often called nanocellulose, are sustainably derived from the cells of trees and agricultural residues. Their unique, high-strength, high-absorbency, low-density biodegradability and renewability make them an attractive feedstock for a range of industrial applications that improve energy efficiency and material productivity through high-strength composites, lightweight materials, and more.[1]
However, a major barrier to increasing adoption of cellulosic nanomaterials is the need to store them in water in low concentration—often only about 3% solids by weight. This makes them energy intensive and costly to ship, and limits their end-use applications. Increasing their concentration through traditional dewatering technologies, such as filtering, centrifugation, and sedimentation, requires large amounts of energy and/or lengthy processing times. In addition to being costly, these methods are susceptible to clogging, and the techniques can adversely impact the properties of the cellulosic nanomaterials.
In response to these challenges, Faraday Technology has invented a scalable, cost-effective, and energy-efficient method to remove the water from cellulosic nanomaterials while retaining their properties. The resulting FARADAYIC®[2] ElectroDewatering process uses the force of an electric field to separate the nanocellulose particles from the water in a FARADAYIC®[3] ElectroExtrusion reactor. As an aqueous suspension of nanocellulose is fed through a hopper to the electrochemical extrusion reactor, the water is continuously removed and the dewatered nanocellulosic material is transported through the reactor by the rotating screw auger.
Through this innovative approach, Faraday has demonstrated an increase in the nanocellulose solids content from 3% to 15% by weight, removing 83% of the water. In addition to making cellulosic nanomaterials more affordable for industry, the reduction in shipping costs is associated with significant energy savings from the fuel needed for their transport.
The novel process itself is also nearly 90% more energy efficient than traditional methods, needing only about 2 kilowatt hours (kWhr) of energy per kilogram of nanocellulose material compared to thermal heating, which requires approximately 19 kWhr, to concentrate the nanocellulosic suspension from 3% to 15% by weight.
Depending on the intended application, the resulting concentrated suspension is ready for use, or a subsequent drying process may be economically applied to remove the remaining water. An added benefit is that, unlike other dewatering methods, the FARADAYIC® ElectroDewatering process does not cause structural damage to the nanocellulosic materials during dewatering.
“We are very excited about the prospects of the FARADAYIC® ElectroDewatering process and associated FARADYIC® ElectroExtrusion apparatus to make cellulosic nanomaterial more energy-efficient and cost-effective for industry,” said E. Jennings Taylor, Founder and Chief Technology Officer at Faraday Technology. “We see promise for this method to address dewatering challenges in additional applications, including for coal or other wet waste/product materials.”
As of the third quarter of 2020, Faraday has generated positive results from bench-scale batch reactor studies and is currently focusing on optimizing the continuous FARADAYIC® ElectroExtrusion reactor for pilot scale demonstration and validation activities.
The Office of Energy Efficiency and Renewable Energy’s Advanced Manufacturing Office (AMO) awarded Faraday Technology $150,000 in 2018 for a phase I proof-of-concept project, followed by $1.05 million in July 2019 for phase II follow-on research and development (R&D) efforts.
This project is one component of AMO’s portfolio of R&D projects with the potential to improve the energy and material efficiency, productivity, and competitiveness of manufacturers across the industrial sector. Learn more about AMO.
[1] Advancing Commercialization of Nanocellulose: Critical Challenges Report, Alliance for Pulp and Paper Technology Innovation, March 2020.
[2] FARADAY® is a registered service mark of Faraday Technology Inc., Reg. No. 3,423,999.
[3] FARADAYIC® is a registered trademark of Faraday Technology, Inc., Reg. No. 3,178,757.