(642f) An Analysis of N-Alkane Polydispersity on the Crystallization of N-Alkanes in Solution

The process of crystallization is of great interest in a wide range of industries. In the oil industry, a major interest is the deposition of wax onto subsea oil pipelines, a costly phenomenon that hinders the production of crude oil. It is known that these deposits are a volume spanning network of orthorhombic, lamellar wax crystals consisting of primarily n-alkanes that entraps some of the crude oil to form a gel. The presence of other materials in a crystallizing system can have an impact on a wide variety of thermodynamic, kinetic and rheologic parameters. Although chemically similar, shorter chained n-alkanes can have a great impact on longer chained n-alkanes. This impact is directly related to the amount of cocrystallization that exists between the n-alkanes, which is dictated by carbon number difference, cloud point and cooling rate.

This presentation will show the impact of n-alkane polydispersity on both thermodynamics and kinetics using a wide variety of experimentation. Cocrystallization shifts the temperature at which crystallization occurs and reduces the heat that is released by the system. Further, it appears that both polydispersity and particularly cocrystallization slow down the kinetics when compared to the monodisperse systems.