Abstract
Paraffin-waxes present in crude oils, at some thermodynamic states, exhibit the phenomenon of crystallization. The onset of wax crystallization temperature of stock tank oil at atmospheric pressure is known as the cloud point. In this paper, cloud point data are presented for several synthetic mixtures and crude oils. The cloud point data have been obtained via three different techniques: Near-Infra-Red (NIR) light attenuation, Dynamic Filtration Cloud Point (DFCP), and ASTM-D2500. For the transparent mixtures, the ASTM-D2500 method is being used as the standard against which the other two techniques are compared to. The data show that all three techniques are consistent with each other, although their precision is different. Because of its simplicity, higher precision, and wide applicability to all kinds of fluids and thermodynamic conditions, the NIR light attenuation technique is recommended.
Furthermore, cloud point and wax deposition data from a variation of the DFCP technique are presented from various crude oils from around the world. Some of these oils contain natural asphaltene dispersants and wax crystal modifiers and as a result, although these oils contain substantial amounts of asphaltene and wax molecules, they remain stable at most thermodynamic conditions encountered during their production. Two cases of these "special" oils are presented here.
