Study On Melting Characteristics Of Spherical Crude Oil Particle Under Mixing Hot Water

Because of its high solidification point,high viscosity,and high wax content,known collectively as the “three highs” of crude oil in China,the temperature of waxy crude oil at a well head is often lower than its solidification point when the amount of liquid produced from an oil well is low,or when the length travelled in a pipe is long.Therefore,the technology for mixing the oil with hot water has been used widely when gathering and transferring crude oil.However,the produced oil cannot be melted quickly with hot water,thus clogging pipes and causing oil well shutdowns.This study investigates the melting process of spherical crude oil particle under mixing hot water using CFD.Firstly,the melting characteristics of crude oil without relative slip between oil and water were studied.The crude oil particle was fixed in a closed cylindrical container filled with water and the effect of the radius of crude oil,water temperature and oil temperature on temperature variations and melting time were described.Secondly,the numerical simulation of crude oil with relative slip between oil and water and the liquid oil did not flow with water was investigated.Temperature variations,liquid frictions,and temperature field structures at variable flow rate,density,latent heat and specific heat capacity were analyzed contrastively.Lastly,the numerical simulation of crude oil with relative slip between oil and water and the liquid oil flowed with water was studied.The effect of crude oil radius,water temperature,oil temperature and flow rate on the melting characteristics of crude oil and the flow pattern of oil droplets were discussed.The results showed that diffusion-controlled melting would cause the unmelted oil to remain a perfect sphere at all times and concentric temperature contours are observed at every instant.The melting time of crude oil decreased with the increase of water temperature,oil temperature and flow rate,but increased with the radius increasing.The liquid oil droplets were gradually separated from the oil and flowed out of the pipe with water and the flow pattern has a significant influence on the melting time in its transition from laminar to turbulent,but has little effect after the transition.These results provide a reference for the hydraulic suspension transport process in waxy crude oil pipelines.