Abstract: A mathematical model for describing the relationship between the viscosity of sheared PPD-beneficiated crude and the entropy generation was developed on the basis of experimental results of PPD-beneficiated Daqing crude.A simplified way to determine the parameters in the model was proposed according to the rules and mechanism of shear effectiveness.In this way,after the viscosity or apparent viscosity of virgin crude,corresponding unsheared PPD-beneficiated crude and the sheared PPD-beneficiated crude at a certain temperature are determined,the parameters in the model can be calculated. The mathematical model can be used to predict the viscosity or apparent viscosity at this temperature of the PPD-beneficiated crude sheared at other temperatures and at various entropy generation.This model combined with a viscosity-temperature model of waxy crude can also be used to predict the viscosities of the sheared PPD-beneficiated crude at other temperature.It is verified that the experimental data of PPD-beneficiated Zhongyuan crude and Lunnan-Qiuling crude blend are in good agreement with predicted results.

Key words: paraffin-base crude, pour point depressant, shear effectiveness, viscosity, entropy generation, mathematical model

摘要： 分析了剪切作用对加剂大庆原油粘度的影响规律,建立了剪切后加剂原油粘度与剪切过程中粘性流动熵产关系的数学模型.根据剪切效应的一般规律及机理,提出了近似确定模型中参数的简易方法.按照此方法,只须测定一定温度下空白原油的粘度或表观粘度、未剪切时加剂原油的粘度或表观粘度,及在某一个剪切温度下及某一个粘性流动熵产条件下原油的粘度或表观粘度,即可近似确定该数学模型中的参数,从而预测在不同温度时剪切后的原油在该温度下的粘度或表观粘度.结合含蜡原油粘度与温度关系机理模型,还可以预测同一加剂原油经受剪切后在其他温度下的粘度.对中原原油和加剂轮南丘陵混合原油加剂试验数据的验证结果表明,该模型有较好的预测准确性.

关键词: 石蜡基原油, 降凝剂, 剪切效应, 粘度, 熵产, 数学模型