Magnetite nanoparticle mediated catalytic aquathermolysis of Omani heavy crude oil

The worldwide demand for energy continues to grow and the production of heavy crude is escalating due to shortage of conventional light crude. The transportation of heavy crude oil from the head-well to the refinery is a challenging task due to its high viscosity and low API gravity. Catalytic aquathermolysis is one of the most significant and cost-effective viscosity reduction techniques employed in the up gradation of the crude oil at elevated temperatures and hence to enhance oil extraction process. In this study, catalytic aquathermolysis of Omani heavy crude oil was performed using magnetite nanoparticles (NPs). The NPs were synthesised by reverse co-precipitation method using iron salts in alkaline medium. The synthesised NPs were characterized using Scanning Electron Microscopy (SEM), X-Ray Powder Diffraction (XRD), Energy Dispersive X- Ray analysis (EDX) and Fourier Transform Infrared Spectroscopy (FTIR). The XRD results exhibited a characteristic peak confirming the high purity of iron oxide nanoparticles. The FTIR spectral analysis designated two well-defined peaks corresponding to wave numbers of 500 ​cm⁻¹ and 630 ​cm⁻¹, endorses the presence of Fe–O. The catalytic aquathermolysis experiments were carried out in a Parr high temperature-high pressure batch reactor at different experimental conditions. The processing parameters in temperature range of 250 ​°C - 300 ​°C, 0.1% to 0.3% catalyst loading, water to oil ratio of 1:7 to 3:7 with 24–72 ​h of reaction time. The initial pressure in the reactor was maintained at 32 ​bars and the optimization was performed using the Taguchi method to maximize the level of heavy oil. An orthogonal array was employed to analyse the effects of mean response and mean signal-to-noise ratio (S/N) to upgrade the heavy oil. The regression analysis was used to establish a relationship between the viscosity and experimental parameters. The experimental outcomes indicates that the maximum reduction in viscosity occurred at a processing temperature of 300 ​°C, 1:7 ​W/O ratio, 0.1 ​wt% of catalyst concentration and 48 ​h of reaction time. Similarly, the optimum conditions for the reduction in API gravity were obtained at 280 ​°C temperature, 3:7 ​W/O ratio, 0.2 ​wt% of catalyst concentration and a reaction time of 24 ​h.