Drag reduction on non-ionic surfactants in aqueous systems

The use of polyoxyethylene alcohol non-ionic surfactants as drag reducing additives in aqueous systems was investigated. Significant drag reduction was obtained with suitable combinations of one percent Alfonic 1214 and salts at 30°C such that the surfactant was near or above its upper critical solubility temperature. Maximum drag reduction was observed at the cloud point. Relative viscosity values also peaked at this point. No upper critical shear stress was attained up to wall shear stresses of 2,000 dynes/cm2 with one percent Alfonic 1214 solutions at their cloud points. At a fixed temperature, the salt concentration required to reach the cloud point is sensitive to the nature of the anion, but is less sensitive to the nature of the cation. Some sensitivity to pH was also observed. The cloud point is not sensitive to the concentration of the surfactant at concentrations below one percent. At 0.5 percent Alfonic 1214, upper critical shear stresses were observed even with solutions at their cloud points. The mechanical degradation is only temporary, however, and drag reduction ability is regained when the shear stress is lowered --Abstract, page ii