The Effect of Cyclic Molecules and Branched Alkanes on the Gelation of Petroleum-like Solutions

During the transportation of petroleum using subsea pipelines, wax deposits can form to block the pipelines at low temperatures. These gels can reduce oil production and are very costly to handle in the petroleum industry. Although numerous components are present in the wax deposits, their primary components are n-alkanes which have low solubility and simple structures.

However, other components in the petroleum are known to influence the properties of wax deposits. In this work, different combinations of n-alkanes were used to represent petroleum waxes using octacosane (C28), dotriacontane (C32) and hexatriacontane (C36). The aim of this work was to investigate the role of cyclic molecules and branched alkanes have on the n-alkane gelation. Phenanthrene (PAH) and squalane (SQ) was chosen to represent cyclic molecules and branched alkanes respectively.

It was found that Both PAH and SQ do not cocrystalize with C32 or C36. Significant amounts of PAH or squalane are needed to influence the gelation of the co-crystalizing n-alkane system. At high concentrations of PAH, the gelation become dependent on PAH. The presence of cyclic molecules or branched alkanes eliminates the dispersant effect of the shorter-chained n-alkane on the longer-chained n-alkane.