Waxy Oil Pipeline Transportation through Cold Flow Technology: Rheological and Pressure Drop Analyses

The cold flow of waxy slurries has been recently appointed as a potential method to avoid or partially reduce the wax deposition in a waxy oil transportation pipeline (Merino-Garcia, D.; Correra, S. Pet. Sci. Technol. 2008, 26, 446-459). An experimental investigation on a large flow loop with rough pipes (inner diameter = 5.08 cm; L similar to 70 m) was then carried out with the aim to study the cold flow of waxy slurries. The wax slurry was constituted by a commercial paraffin wax distribution in n-decane, previously characterized from a rheological point of view. The influences of the wax concentration and flow rates on the pressure drop were investigated by loop runs. A comparison between the experimental pressure drop and modeling results was carried out by investigating friction factor correlations suitable for waxy slurry flow. Furthermore, the same set of data was used, regardless of the rheological characterization, to assess the theological behavior of the suspensions. This second approach has allowed evidence for the importance of a correct estimation of bulk viscosity to correctly predict the pressure drop. The tests carried out constitute a proof of concept for the waxy cold flow transportation technology.