Removal of nickels from crude oil to water by two micro-sized core-shell particles bearing poly(N-vinyl pyrrolidone)

Abstract Nickel in crude oil deactivates hydrocracking catalysts, which imposes adverse effects on the subsequent processing of crude oil. However, the commonly used acidic agents always corrode the processing equipment, and phosphoric agents often introduce in extra pollutions. Therefore, an efficient and environmentally friendly nickel removal agent is urgently needed. In this work, micro-sized SiO 2 coated by poly( N -vinyl pyrrolidone) (PVP) (PVP@SiO 2 -C) and grafted by PVP (PVP@SiO 2 -G) are prepared and characterized by FT-IR, TGA, elemental analysis, SEM and TEM. Both of core-shell particles exhibit excellent nickel removal rate for crude oil. The influences of particle concentration, electric desalting temperature and oil/water ratio on nickel removal rate are further studied. It is found that, when the concentration is lower than 4000 ppm, the nickel removal rate increases with increasing particle concentration. Appropriate temperature and oil/water ratio benefit for the removal of nickel. Since the PVP@SiO 2 -G exhibits a much better nickel chelating ability than PVP@SiO 2 -C, the nickel removal rate of PVP@SiO 2 -G reaches as high as 64.4%. In addition, PVP@SiO 2 -G also shows a favorable removal selectivity for nickel at low calcium concentrations. These results indicate that core-shell particles PVP@SiO 2 -G have great potential for nickel removal from crude oil to water.