Reza Azin

Wax deposition is a common problem in oil pipelines and production systems. In this study, impact of water cut, mixing rate, chemical inhibitor, and time on wax deposition were investigated in a cold fnger setup. Efect of diferent chemical inhibi-tors on wax appearance temperature (WAT) was studied using viscometry and diferential scanning calorimetry techniques. Results suggested that WAT reduced with increasing inhibitor concentration, with 800 ppm being the optimum. Also, chlo-roform–toluene–ethylene vinyl acetate (EVA) mixture with 30, 30, and 40 wt% had the highest performance and reduced the WAT to 16.7 °C. Mixtures of toluene—EVA with acetone, p-xylene, and disulfde oil (DSO), followed next. Moreover, deposition decreased with increasing temperature diference between oil and pipe at constant cold surface temperature and increased upon increasing temperature diference at constant oil temperature. Wax deposition in two-phase system was lower than in single-phase system, but increased by increasing water cut. EVA–toluene, 2 wt% DSO, 2 wt% acetone, and 2 wt% p-xylene mixtures reduced the deposition to 23.33, 21.71, 32.14, and 12.5%, but addition of 2 wt% of EVA–DSO–acetone mixture reduced deposition to 35.74%. At similar operating conditions, fow turbulence has greater impact on reducing wax deposition, and its efect is enhanced using a proper inhibitor.