Effect of DSO, EVA, and SiO2 and clay nanohybrids on rheological properties of waxy oil mixtures

Wax deposition causes serious problems during oil production and transportation through pipelines. In this study, the influence of disulfide oil (DSO), ethylene vinyl acetate (EVA) copolymer as pour point depressant (PPD), SiO2 and clay nanoparticles on rheological properties of waxy oils are investigated. The viscoelastic modulus, viscosity, pour point, surface tension and yield stress of different waxy oil samples were measured. It was observed that the gel point, pour point, viscosity, gel strength, and yield stress decreased upon addition of these additives to waxy oil. It was found that rheological properties of oil samples improved by increasing SiO2 and clay nanoparticles up to 0.2 wt% in nanohybrid PPD (NPPD) and decreased at higher concentrations. Also, results indicated that SiO2 nanoparticles had better performance for wax prevention compared to clay, EVA, and DSO. Our measurements showed that yield stress decreased to 0.049 Pa by adding 0.12 wt% of SiO2 nanoparticle into NPPD whereas it was 54.3 Pa for blank oil. Also, pour point and surface tension of oil doped with SiO2 NPPD significantly reduced by increasing nanoparticle concentration. Moreover, it was found that DSO as a waste by product of gas refinery has a performance similar to EVA for wax prevention.