Dispersed Nickel-Based Catalyst for Enhanced Oil Recovery (EOR) Under Limited Hydrogen Conditions

Heavy crude oil enhanced into a lighter oil by hydrocracking process with nickel nanoparticles (Ni NPs) as catalysts. Ni NPs were synthesized by colloidal method (chemical reduction of metal salts). The reduction of nickel nitrate hexahydrate ((Ni(NO 3 ) 2 ·6H 2 O) was done using sodium borohydride (NaBH 4 ) as a reducing agent in presence of polyvinylpyrrolidone which worked as a protective and stabilizing agent; ethanol was used as a solvent. The properties of the nanoparticles were investigated by FT-IR, TEM, XRD, and HRTEM. These techniques confirmed the formation of Ni NPs with an average size of 10 nm and a tetragonal structure. The experiments were carried out in a batch reactor at 45 Kg f cm −2 (initial H 2 pressure), 380 °C, stirring speed of 500 rpm and reaction time of 1 h. In all cases, the increase in the concentration of Ni nanoparticles improved the physical and chemical properties of heavy crude oil, even in limited hydrogen conditions; these properties were measured in terms of viscosity, SARA analysis, sulfur and nitrogen removal, and chromatographic analysis of gaseous products. The asphaltenes conversion was of 26.31% and moderate sulfur removal was achieved, these results are promising for EOR application. Graphic Abstract