Low-temperature flowability characteristic of waxy crude
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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.
Key wordswaxy crude low-temperature flowability viscosity-temperature chart
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- ZHANG Jin-jun, LIU Zhong-hui, ZHANG Fan, et al. Waxy crude treated with pour-point-depressants: Flow behavior and its evaluation[C]// Proceedings of the 1997 International Symposium on Multiphase Fluid, Non-Newtonian Fluid and Physico-Chemical Fluid Flows, ISMNP’97. Beijing: Int Acad Publish, 1997.Google Scholar
- ASTM D5133-99 standard test method for low temperature, low shear rate, viscosity/temperature dependence of lubricating oils using a temperature-scanning technique[S]. Annual Book of ASTM, 2001.Google Scholar
- RIGA A T, ROBY S H. Low-temperature properties of crankcase motor oils: A fundamental approach to pumpability phenomena[J]. Lubrication Engineering, 1994(5): 411–417.Google Scholar