Polyelectrolyte flocculation of grain stillage for improved clarification and water recovery within bioethanol production facilities.
Polyelectrolytes were investigated for flocculation of a corn whole stillage stream to improve solid-liquid clarification operations and reduce downstream utility requirements for evaporation and drying within a bioethanol process. Despite a negative zeta potential for the stillage solids, an anionic polyelectrolyte was found to provide the best flocculation. At the optimal dosage of 1.1mg polymer/g dry suspended solids, an anionic flocculant provided a clarified stream with only 0.15% w/w suspended solids (equivalent to a total dissolved solid to total suspended solid ratio greater than 40, and a viscosity reduction of 39% compared to an unflocculated "clarified" stream). The resulting solids cake had greater than 40% w/w solids, and more than 80% water recovery was found in the clarified stream. Addition of flocculant improved filtration flux by six fold and/or would allow for up to a 4-times higher flow rate if using a decanting centrifuge for clarification of corn stillage.
Menkhaus
Todd J
TJ
South Dakota School of Mines and Technology, Department of Chemical and Biological Engineering, Rapid City, SD 57701, USA. Todd.Menkhaus@sdsmt.edu
Anderson
Jason
J
Lane
Samuel
S
Waddell
Evan
E
D056804:Biofuels; D002498:Centrifugation; D004573:Electrolytes / Q000737:chemistry*; D004736:Energy-Generating Resources; D000431:Ethanol / Q000378:metabolism*; D005374:Filtration; D005427:Flocculation; D012995:Solubility; D014783:Viscosity; D018508:Water Purification; D003313:Zea mays / Q000378:metabolism*
D056804:Biofuels; D004573:Electrolytes; D000431:Ethanol