Low-temperature flowability characteristic of waxy crude

Abstract

Viscosity variation with temperature was measured by temperature scanning procedures in a coaxial cylinder viscometer. An eigen-temperature is found in viscosity-temperature chart generated from the temperature sweep experiment. It is the temperature corresponding to the maximum value of the curvature of a non-dimensional viscosity-temperature chart. The experimental results show that the eigen-temperature varies linearly with shear rate and cooling rate. Eigen-temperatures decrease either with decreasing the shear rate or with increasing the cooling rate. The eigen-temperatures of PPD-beneficiated crudes are more sensitive to the shear and cooling rate than those of virgin crudes. The eigen-temperature of virgin crude is almost equal to its pour point, while the eigen-temperature of PPD-beneficiated crude is much lower than its pour point. This indicates that the eigen-temperature may be applied to assess the flowability of waxy crudes with various shear and thermal histories, and may also provide a new means to evaluate the effect of PPD on the low-temperature flowability of waxy crude.

Keywords

waxy crude / low-temperature flowability / viscosity-temperature chart