Polymer nanocomposites to modify crude oil waxy crystallization: Influence of content and type of clay (mineral)

Abstract

Some operational problems in the oil industry are due to the precipitation of paraffins. To prevent them, a possible strategy is the use of polymeric additives. Polymeric nanocomposites have proved to be a promising alternative in waxy model systems. The article reports the evaluation of nanocomposites of poly(ethylene-co-vinyl acetate) (10 mol% vinyl acetate) (EVA) with palygorskite, montmorillonite or halloysite as pour point reducers in different types of crude oil: two paraffinic oils (°API = 26.4 and 28.8) and one oil without n-alkanes, which was doped with different wax concentrations (pour point of 56–58 °C). The performance of nanocomposites was evaluated by pour point (PP), microcalorimeter (μDSC), optical microscope and rheological measurements. The nanocomposites reduced PP of different oils, being more efficient than pure EVA since the nanocomposites reduced PP by up to 43.5 °C, whereas the EVA reduced PP by a maximum of 9 °C. In general, the additives modified the precipitated wax crystals, but they had difficulty acting in the oil with the highest n-alkane content. Nanocomposites reduced the wax appearance temperature of the oil with 24% w/w n-alkanes by approximately 12 °C. They also reduced the viscosity of the oil samples. Among the evaluated materials, EVA:palygorskite and EVA:halloysite nanocomposites were the most efficient pour point reducers.