基于新型Couette结蜡装置的长庆原油结蜡特性及模型建立

Study on wax deposition of Changqing crude oil based on a newly developed Couette device

利用自行研发的Couette结蜡装置考察壁面油温、油壁温差、壁面剪切等因素对长庆原油蜡沉积速率的影响;通过FLUENT软件模拟结蜡装置内部的流场及温度场,得到结蜡筒壁面处黏度、温度梯度、剪切应力等参数,建立适合长庆原油的蜡沉积模型。结果表明:不同油温、油壁温差、样品筒转速条件下,主导长庆原油蜡沉积速率的内在因素依次为壁面处的蜡晶溶解度系数、壁面处的温度梯度和壁面处的剪切应力;数值模拟结果与实际管线的流场、温度场分布规律相吻合;模型计算值与试验测量值的平均误差为6.47%。试验结果较好地反映了长庆原油的蜡沉积特性,验证了装置的可靠性、算法的可行性和研究方法的可推广性。

In this paper, a systematic research on the law of wax deposition for Changqing crude oil under various experimental conditions was carried out in an small Couette wax deposition device independently developed. FLUENT software was applied to simulate the flow and temperature field of crude oil inside this new device to obtain the precise parameter values such as viscosity,temperature gradient,shear stress and so on. The results show that wax crystal solubility coefficient, temperature gradient and sheer stress at the wall plays a major role in the internal mechanism under different operating conditions, respectively. The simulation result agrees well with the distribution of the flow and temperature field in actual pipelines. The dynamic model of wax deposition for Changqing crude oil was established with an average error of 6. 47%. Thus the feasibility of this new method was confirmed and could be used for the further research on wax deposition.