Rheology and phase behavior of highly paraffinic 'waxy' mixtures.

摘要

The rheological behavior of waxy crude oils is crucial in the design of pipelines for transportation and down-stream processing equipment. Most of these types of crude oils exhibit a combination of time-independent and time-dependent rheological properties.;A differential Scanning Calorimeter was used to investigate the phase behavior of the paraffinic mixtures. Additional experiments for the wax appearance temperature were performed using video-microscopy, differential scanning calorimetry, viscometry and a visual method.;The rheological measurements were performed using a concentric cylinder viscometer. Experiments were performed with prepared samples of paraffinic mixtures, using dodecane or hexadecane as the solvent and a paraffin wax as the solute. The effects of mixture composition, cooling rate and shear rate on the apparent viscosity were studied over a range of temperatures. The variations in viscosity with composition and shear rate were found to be quite significant; however, the effect of cooling rate was not as appreciable. The experimental data have been correlated by the following equation for apparent viscosity:; lnmapp= A+BT-1+C g&d2;-0.5+D w