Influence of Operating Conditions on Crude Oil Transportation

*E.E.zorgani¹. H.A.Mansoori²,. W.S.Kassim²,

¹petroleum research centre, Tripoli, Libya^{, 2} Alfateh university, Tripoli, Libya,

Transportation of high pour point crude oils in flow lines and pipelines may require special considerations.  Design of sub-sea flow lines requires even more attention to reduce or eliminate possible deposition of wax and solids on the inner wall of the pipe.

This paper presents the results of experimental investigation of cooling rate as expressed in terms of wall temperature and temperature difference across the pipe wall on wax deposition from a high pour point, Bouri crude oil.  Tests were carried out in a test section consisting of a jacketed copper tube, 2.20 meters long and 9.76 mm ID.

Obtained results show that the effect of coolant temperature and crude oil temperature is quite apparent.  For a given flow rate,  wax deposition rate increases as the temperature difference between the coolant fluid and circulating crude oil increases. This temperature difference represents the temperature gradient across pipe wall, which appear to be an important factor. The results show that there was an initial period over which the pressure drop increases steadily, an indication of steady build-up of wax, and then declined gradually due to decreased deposition caused, apparently, by thermal lagging effect of deposited wax. The results regarding the viscosity of the circulating oil indicated an increase of its viscosity with time (i.e. with wax deposition). This shows that the crude oil was being deprived from its paraffinic materials and becoming more aromatic during the course of wax deposition.

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