Dewatering of Biomass Using Liquid Bio Dimethyl Ether

Abstract

An interesting integrated configuration in a thermochemical conversion biorefinery that is producing dimethyl ether (DME) is to use a small fraction of the BioDME for dewatering of the solid biomass feedstock. Therefore, the use of liquid BioDME was investigated in this study for pressurized dewatering of biomass at room temperature. Water was removed in liquid form from wet sawdust and wet wood chips using liquid DME in a laboratory-scale batch unit. Both the sawdust and the wood chips could be dewatered in a short time (minutes) to a moisture content of 15% (w/w) from an initial content of approximately 55% (w/w). Longer DME treatment times (hours) lowered the moisture content even further down to 8% (w/w), indicating that the transport phenomena in the porous biomass and the solubility of DME in water influence the dewatering characteristics. The DME dewatering performance, 12–22 g DME per g water removed, was similar to literature data on coal dewatering using liquid DME. The present study showed that DME dewatering of the solid biomass feedstock has potential as an energy-efficient dewatering process, especially in an integrated thermochemical conversion biorefinery.

Keywords:

• Biomass
• Dewatering
• Dimethyl ether
• Drying
• Gasification

ACKNOWLEDGMENTS

The work was financially supported by Processum Biorefinery Initiative AB. Preem is acknowledged for supplying BioDME for the tests. Marcus Gullberg kindly supplied the wet sawdust and Smurfit Kappa Kraftliner supplied wood chips for the experiments.