Wax deposition in single phase flow

A series of experiments on wax deposition from oil have been performed in a 50-m long by 43.4 mm ID jacketed flow loop at Tulsa University. Tests were performed on a 35 degrees API crude oil from the Gulf of Mexico with a wax appearance temperature (WAT) of 120 degrees F. The series of tests were de signed to determine temperature and flow rate effects on the deposition rat e and fraction of oil in the deposit. The deposit thickness in the flow loo p was determined using five methods; pressure difference, energy balance, t he spool piece volume change (LDLD), ultrasonic transit time, and direct me asurement in a test section. Samples of the deposits were analyzed at the c onclusion of each test for included oil. The effect of the difference in te mperature between the oil and pipe wall showed a simple increasing depositi on rate with temperature difference. The change in deposition rate was a we ak function of oil temperature relative to WAT. The variation in deposition rate with flow velocity gave large differences between laminar and turbule nt flow. Deposit oil contents decreased with increasing flow velocity. The fraction of oil in the deposit decreased with time in turbulent Bow tests b ut did not change in laminar tests. (C) 1999 Elsevier Science B.V. All righ ts reserved.