In-situ SAXS/WAXS and turbidity studies of the structure and composition of multihomologous n-alkane waxes crystallized in the absence and presence of flow improving additive species

Wax deposition on engineering components can cause severe operational problems in oil recovery. These problems are examined through a study focused on understanding the mediating role played by the chemical inhibitors that are commonly used to prevent or delay the wax crystallization process. Solution crystallization data from homologous mixtures of n-alkanes, as measured via optical turbidometric methods and in-situ combined small and wide-angle X-ray scattering (SAXS/WAXS) techniques, reveal a direct correlation between the type and concentration of polymeric additive used and the resultant crystallization behavior. The behavior of additives, such as polar macromolecules with nonpolar alkyl chains protruding from the backbone, was consistent with their binding within the basal plane of the wax crystal structure, associated with intermolecular (alkane/additive) interactions of an epitaxial nature. Overall, the results were consistent with a number of structurally related factors influencing the additive-mediated wax crystallization process. The c-axis of the additive-mediated crystallized wax was found to be related to the longest chain in the homologous wax mixture, the a and b axes were determined by the inhibitor family used, and the inhibitor efficiencies were determined by the chain lengths of the alkyl chains protruding from the inhibitor backbone.