Effect of nanoparticle modified polyacrylamide on wax deposition, crystallization and flow behavior of light and heavy crude oils

In this article, the potential use of silica and alumina polyacrylamide to inhibit wax crystallization and deposition of real crude oils has been studied for the first time. The performance of nanocomposites on a light and heavy crude oil was evaluated using cold finger apparatus, differential scanning calorimeter (DSC), polarizing microscopy, and rheometer. Nanocomposites effectively reduce wax deposition with 79% and 70% maximum efficiency for heavy and light oil, respectively. The flowability of treated heavy oil was improved, while a less pronounced effect was observed for treated light oil. DSC measurements indicated nanocomposites to delay the wax crystallization onset of heavy oil more noticeable than light oil. Polarized microscopy showed a visible morphological change, as the introduction of nanocomposites caused regular roundly shaped and finely dispersed wax crystals for both light and heavy crude oils. The results indicate that the presence of nanocomposites delays the wax crystallization process by presenting multiple spherical nucleation templates, influencing the wax crystal interactions, and preventing the formation of stable wax networks in agreement with the percolation theory predictions. The better inhibition effect of nanocomposites for heavy oil may result from two mechanisms. First, the well-dispersed nanocomposites act as nucleation centers for wax crystals. Second, asphaltene adsorption on the nanocomposite surface may prevent the formation of the asphaltene-wax three-dimensional network and delays wax crystallization. This research indicates the possibility of using silica and alumina polyacrylamide as an effective chemical agent for the inhibition of wax deposition of crude oil.