Enhancing the flow and density characteristics of East Baghdad heavy crude oil using alumina-based nanofluid and direct mixing systems: a PIPESIM-aided evaluation
摘要
Heavy crude oils are characterized by complex thermo-rheological behavior which is controlled by asphaltene–resin colloidal networks resulting in high viscosity, low API gravity, and high hydraulic losses when transported through the pipeline. These temperature-sensitive structural interactions require control in order to optimize the efficiency of the flow and lower the amount of energy required. An ultrasonic-assisted γ-Al2O3 nanofluid was considered as a thermally responsive upgrading technology to East Baghdad heavy crude oil in this study. Two preparation routes were investigated: (i) a pre-prepared nanofluid (50 nm, 2000 ppm) ultrasonically dispersed with 200 ppm SDBS in kerosene prior to blending and (ii) a directly mixed nanoparticle–surfactant–solvent system at an 18% (v/v) ratio. Rheological and density measurements were conducted over 20–75 °C and 15–60 min treatment intervals. The pre-prepared nanofluid increased API gravity from 19.6° to 30.5° and reduced viscosity from 58.15 to 5.58 cP (≈ 90.4% reduction at 20 °C), whereas the directly mixed system reduced viscosity to 11.95 cP (≈ 79.4%) and increased API to 29.27°. Thermogravimetric analysis confirmed the thermal stability of γ-Al2O3 nanoparticles with < 2% mass loss up to 800 °C. Steady-state PIPESIM simulation of a 40 km, 16-inch pipeline transporting 25,000 bbl day−1 demonstrated that the viscosity reduction decreased hydraulic power demand from 59.5 kW (untreated crude) to 27.97 kW after nanofluid treatment, corresponding to approximately 53% energy savings. These findings establish that controlled ultrasonic pre-dispersion of alumina nanoparticles provides measurable thermo-rheological modification and quantifiable hydraulic benefits for heavy crude oil transport.