Viscosity reduction for flowability enhancement in Iraqi crude oil pipelines using novel capacitor and locally prepared nanosilica

The aim of the present work is to reduce the viscosity of Iraqi heavy crude oil to enhance its flowability in pipelines. This has been done by applying an effective electrical field through design and implementation of an invented capacitor. In order to attain this objective; an experimental rig has been built. It consisted of: a crude oil pipe, a novel parallel plate capacitor, an oil pump, a solenoid valve, a viscometer, and a control unit (relay, voltage regulator, rectifier, timer, and digital voltmeter). The experimental work was performed according to central composite rotatable design for three operating variables: treatment time (0-60 s), applied voltage (140-220 v), and space between capacitor electrodes of (2-10 cm). The optimum conditions were obtained using STATISTICA and WinQSB softwares. At optimum conditions, locally prepared nanosilica has been employed with different concentrations (0-700 mg/L) to show its effect on crude oil viscosity in the presence of an electrical field impact. The results showed that the viscosity was reduced significantly with increasing treatment time, voltage, and distance between electrodes. The Minimum viscosity obtained was at 32 s treatment time, 188 V, and 6.11 cm distance between capacitor electrodes. This represented the optimum conditions with a minimum viscosity of 20.479 cSt. Afterwards, the viscosity increased due to particles aggregation. At optimum conditions the fluid flow characteristics obtained were: 2630.93, 0.4089 gm/cm(2), 0.2657 gm/cm(2), and 57.059 W S, for Reynolds number, shear stress, pressure drop, and power consumption, respectively. The experimental results proved that the invented capacitor offered a good reduction in viscosity and a good saving in power of 37% at optimum conditions achieved at 10 +/- 2 degrees C. The nanosilica optimum concentration was 100 mg/L that gave a minimum viscosity of 12.8 cSt with a reduction percentage and power saving of 60.6%. The viscosity reduction has lasted for 11 h.