Microscopic characteristics of wax crystals particles under different pressures

Key words:  wax crystal particles  pressure environment  wax appearance point  micro characteristics

Abstract:

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.