EVA/SiO ₂ Nanocomposite Pour Point Depressant for Enhancing Flow Properties of Indian Waxy Crude Oil

The accumulation of wax poses a significant challenge in transporting Indian waxy crude oils, especially under low-temperature conditions. A nanocomposite pour point depressant─EVA/SiO2, based on ethylene-vinyl acetate copolymer (EVA) and inorganic silica (SiO2) nanoparticles─was synthesized and evaluated for its effectiveness in enhancing the flow properties of an Indian waxy crude oil. The EVA and EVA/SiO2 were characterized using FTIR, TGA, FE-SEM, and HR-TEM, and their performance was comparatively evaluated through pour point measurement, rheological analysis, wax appearance temperature and gelation point determination, aging studies, and pipe flow loop testing. The results suggest that the EVA/SiO2 substantially outperforms the EVA in enhancing the flow properties of crude oil. The EVA/SiO2 nanocomposite was effective in lowering the pour point by 17 °C and the viscosity by 83.9% at 25 °C and 97.5% at 40 °C at an optimal dosage of 1500 ppm. Wax appearance temperature and gelation temperature of crude oil treated with the EVA/SiO2 dropped significantly from 62 to 32 °C and 52 to 24 °C, respectively, indicating notable improvements in low-temperature flow behavior. Aging studies revealed that treated samples retained their flow characteristics even after 1 week of storage and showed only minor deterioration, indicating long-term flow stability. Optical microscopy revealed that the EVA/SiO2-treated samples contained much finer, less aggregated wax crystals. This study integrated flow-loop studies and demonstrates an 88% reduction in pressure drop gradient at 40 °C for the EVA/SiO2-treated sample. These results show that the EVA/SiO2 nanocomposite significantly outperforms EVA in efficacy as a pour point depressant for improving the flow properties of Indian waxy crude oil.