Flowability enhancement of waxy crude oil using gamma-irradiated EVA-copolymers grafted with novel functionalized monomers

Recent research has identified a key limitation in the petroleum sector commonly used pour point depressant (i.e., EVA-copolymer), which shows decreasing efficiency as the paraffin wax content increases. To address this issue, this study explored the enhancement of EVA-copolymers as pour point depressants for waxy crude oil through the gamma irradiation grafting of homopolymers with long alkyl chains onto EVA copolymers to produce (EVA-g-p(HDOAB) and EVA-g-p(HDAOCP)⁺Br⁻). FTIR and ¹H-NMR spectroscopy show that EVA-g-p(HDOAB) and EVA-g-p(HDAOCP)⁺Br⁻) were successfully prepared using gamma radiation. Various concentrations (100, 500, 1000, 2000, and 5000 ppm) of the grafted EVA-copolymers were introduced into the crude oil. The grafted copolymers showed a significant reduction in pour point from 24°C to -18°C and -15°C at a 2000 ppm concentration, outperforming pure EVA, which only reduced the pour point to -9°C. Additionally, both grafted copolymers demonstrated notable viscosity and shear stress reductions, particularly at temperatures close to the pour point. The enhanced low-temperature flow properties are attributed to the synergistic effect of the grafted EVA-copolymer acting as nucleating agents that modify crystallization patterns and inhibit crystal growth. This study underscores the potential of using gamma ionizing radiation to develop high-performance PPDs for crude oil.