【摘要】 我国已有多条原油长输管线应用降凝剂，革新了老管线传统的输油工艺和新管线传统的投产工艺，并取得了巨大的经济效益。在析蜡点以上，泵剪切和管流剪切对原油的低温流变性无影响；在析蜡高峰区内，泵剪切对原油的低温流变性有恶化作用，管流剪切对原油的低温流变性有改善作用，但这种作用是有条件的。更多还原

【Abstract】 This paper introduces the results of using pour point depressants(PPDs) for crude oil in long distance pipeline transportation in China. The data of pour point depression, viscosity reduction and abnormal point decrease of the crude oils being transported in more than 10 pipelines(over 1 year for the most pipelines) are tabulated and analyzed and tremendous economic benifits are obtained. It is shown that both the pump and the pipeline shear do not affect the rheologic behavior of the crude oil above its waxing out point; the pump shear can deteriorate but the pipeline shear can improve the rheologic behavior near the peak temperature of waxing out at special conditions.更多还原