含蜡原油蜡晶颗粒分布特征的定量分析

Quantitative analysis on distribution characteristics of wax crystal particles in waxy crude oil

借助数字化图像处理技术,已有研究成功实现了对蜡晶形态和尺寸的定量描述,但鲜有研究关注蜡晶颗粒粒径的分布特性。借鉴材料学中有关定量描述颗粒群粒度分布特性的方法和参数,实现了对原油中蜡晶颗粒分布特性的定量描述。使用颗粒粒径分布宽度系数定量表征了蜡晶颗粒粒径分布的宽窄,并结合蜡晶颗粒的粒径分布直方图直观地描述了蜡晶粒径在各个区间内的分布频率,通过计算蜡晶颗粒粒径分布的分形维数定量表征了颗粒粒径分布的不规则性。对含蜡原油加剂前后的蜡晶显微图像的分析结果表明,加剂后蜡晶颗粒的粒径增大,粒径分布宽度系数增大,粒径分布变宽,颗粒分布的分形维数增大。

With image processing techniques, some studies have successfully realized the quantitative description of wax crystal morphology and size. However, few studies focus on the wax crystal particle size distribution characteristics. In this paper, quantitative description of waxy crystal particle distribution characteristics is achieved by referring to the methods and parameters for describing particles group size distribution characteristics in material fields. By using the particle size distribution width coefficient, the wax crystal particles size distribution width is quantitatively characterized. The wax crystal particle diameter in each frequency range is clearly denoted by combining with histogram of wax crystal particles size distribution. The irregularity of waxy crystal particle size distribution is quantitatively expressed by the fractal dimension of wax crystal particle size distribution. The analysis results of wax crystal microscopic images of both virgin waxy crude oil and its corresponding pour-point-depression （PPD） beneficiated oil show that the wax crystal particles size increased, and the particle size distribution width coefficient increased as well after PPD treatment. Moreover, the size distribution turned wider, and the fractal dimension of wax crystal particle size distribution increased. （3 Figures, 1 Table, 23 References）