Dielectrophoretic Enhancement of Dewatering

The transition of cellulosic nanomaterials to pilot scale production makes them feasible for use in a variety of industrial applications including oil and gas, wastewater treatment, electronics, and others.A significant hindrance for further advancement is the difficulty of drying these materials without aggregation.Long-distance shipping is not economical due to this difficulty combined with their significant content of water (from 94% to 97%).Thus, one of the major manufacturing challenges is to obtain dry cellulosic nanomaterials while maintaining their nanoscale dimensions.A new dewatering technology with breakthrough efficiency and power performance has been developed.It greatly exceeds the Department of Energy requirements and is proposed to be productized in a Phase II effort.The technological equipment integrates the electrospray in vacuum and lyophilization that allows the drying of nanocellulose without compromising the nanoscaling.Atomization of the nanomaterial pulp mitigates the agglomeration of nanocellulose particles and dramatically increases the evaporation of generated droplets that result in the freezing and sublimation of the water.A prototype reactor was built, evaluated, improved, and demonstrated to meet or exceed all requirements.Nanocellulose containing pulp (3% of nanofibers or 6% of nanocrystals) was successfully electrospun in a vacuum (28 inHg) with the constant evacuation of water vapor to produce dry nanocellulose with ~1% bound water content.The energy consumption by the Phase I benchtop-scale prototype was estimated as 32 kWh/kg for nanofibers, 19 kWh/kg for nanocrystals, and ~0.34 kWh/kg for the water recovery.This work eliminated all major risk items, leaving the scaling up of the equipment, an addition of operational features, and a demonstration of a small batch scale unit for Phase II.With all major aspects of the system’s technical feasibility convincingly demonstrated in Phase I, most of the Phase II resources will be invested in the full design and fabrication of a small batch scale unit, developing the final control electronics with all operational features and internal diagnostic capabilities, and a demonstration of the final test unit for extended operation and scientific validation.The main potential markets for nanocellulose utilization include viscosity modifiers for paints, reinforcing material for cement and polymers, additives to improve barrier performance in coatings, and wet-end additives to enhance the strength and improve the dewatering of paper.The intent of the proposed technology is the efficient dewatering of nanocellulose without compromising its properties, which will dramatically reduce the cost of transportation.