Microscopic Study of Wax Precipitation—Static Conditions

Abstract

The scalability of available wax deposition models is still limited, partly due to the lack of mechanistic understanding on the wax deposition processes. In an attempt to enhance the understanding of wax deposition physical mechanisms, a systematic microscopic visualization experimental program is necessary. The static microscopic tests are performed with 100× magnification under controlled cooling rate conditions. An in-house MATLAB-based program is developed to enable measurements of morphological features such as size and aspect ratio. The two-dimensional (2-D) aspect ratio distribution of the crystals resembles a log-normal pattern with a mode of 2–3. Moreover, the 2-D size distribution of the crystals resembles an exponential decay pattern with a mode of 20–40 μm2. These tests also showed that there is no significant change in crystal aspect ratio during isothermal conditions over 48 h. In addition, it is also observed that the wax crystal precipitation rate is dependent on the cooling rate owing to the effect of supersaturation. Although static tests may not be directly applicable to wax deposition under flow conditions, they provide valuable insight for designing and analyzing difficult flowing visualization experiments.