压力作用下油品蜡晶颗粒微观特征

Microscopic characteristics of wax crystals particles under different pressures

压力会影响管输油品宏观流动特性,但其对内部微观颗粒的作用机制尚不明晰。自主研制带压显微冷热平台,实现0~5 MPa压力范围内油品中蜡晶颗粒的微观结构可视化;制备特殊结构的载玻片,保证油膜铺展厚度一致,最大限度地降低油膜厚度对光学显微测试结果的影响。利用氮气控制体系压力,分别测试恒温加压与恒压降温过程中油品蜡晶颗粒数量、尺寸、盒维数、圆度等微观参数的变化规律,讨论压力对油品内部蜡晶颗粒微观特征的影响规律。结果表明压力增加会导致油品析蜡面积增大、蜡晶颗粒数增多,造成油品析蜡点升高;恒温加压时,蜡晶颗粒尺寸基本不随压力变化,而恒压降温时,蜡晶颗粒尺寸随压力有明显变化;压力增加会导致蜡晶颗粒不规则程度增加,有利于蜡晶颗粒之间的交联。

Pressure can affect the macro flow characteristics of the pipeline oil,but the mechanism of its effect on the internal micro-particles is not clear.In the current work,a hot-cold platform with pressure to visualize the microstructures of wax crystal particles in oil products in the pressure range of 0-5 MPa is developed.In order to ensure the consistency of oil film spreading thickness,a special structure of glass slide was prepared to reduce the influence of oil film thickness on the detection results via the optical microscope.By using nitrogen to control the pressure of the system,the changes of micro-scaled parameters such as the count,size,box dimension and roundness of wax crystal particles in oil products during the process of"constant temperature pressurization"and"constant pressure cooling"were measured,and the influence of pressure on the micro-characteristics of wax crystal particles in oil products was discussed.The result shows that the increase of pressure will lead to the increase of wax precipitation area,wax crystal number and wax precipitation point.When the temperature is constant and the pressure is applied,the size of wax crystal particles does not change with the pressure.However,when the temperature is constant and the pressure is reduced,the size of wax crystal particles changes significantly with the pressure.The increase of pressure will increase the irregularity of wax crystal particles,which is beneficial to the crosslinking of wax crystal particles.