Rheological and drag reduction properties of hydroxypropyl xanthan gum solutions

Hydroxypropyl xanthan gum (HXG) was prepared from xanthan gum (XG) and propylene oxide under alkaline condition. Rheological and drag reduction properties of different concentrations of aqueous HXG and XG solution were studied. The micro-structure network of HXG and XG solutions was investigated by Cryo-FESEM. The results showed that HXG and XG solutions could exhibit shear thinning property. The apparent viscosity of 6 g·L− 1 HXG solution was 1.25 times more than that of 6 g·L− 1 XG solution. The storage modulus G′ and the loss modulus G″ of HXG solutions were greater than those of XG solutions, and thixotropic and viscoelastic properties were more significant in HXG solutions. The HXG and XG solutions reduced the pressure drop of straight pipe, and the maximum drag reduction of 1 g·L− 1 HXG and XG in smooth tube reached 72.8% and 68.1%, respectively. Drag reduction rate was increased as the concentration increased. The HXG solution may become a new polymeric drag reducer.

Graphical abstractThe figures show the drag reduction R(%) of the hydroxypropyl xanthan gum (HXG) and xanthan gum (XG) solutions against generalized Reynolds number ReG at different concentrations. For each solution, R(%) first increases with ReG and then remains largely steady with further increase in Re at higher flow rates. Under the same concentration, the drag reducing behavior of HXG solution is superior to the XG solution.3 g·L− 1 HXG solution could keep the viscosity more than 50 mPa·s at the constant temperature of 80 °C and constant shear rate 170 s− 1 for 90 minFigure optionsDownload full-size imageDownload as PowerPoint slide