Evaluation of laminar flow of surfactant-stabilized bitumen-in-water emulsion in pipe using computational fluid dynamics: Effects of water content and salinity

Abstract

Laminar flow of oil-in-water (O/W) emulsion in a horizontal pipe has been simulated to quantify the effect of salinity of aqueous phase and water content on flow characteristics using computational fluid dynamics (CFD). Bitumen was dispersed in aqueous solution containing surfactant at different NaCl concentrations and water contents. Rheological parameter was obtained from the viscosity-shear rate profiles of the fluid. Numerical modeling and simulation was performed using a finite element simulation software. The case was simplified by considering the O/W emulsion as a stable, pseudo-homogeneous (single-phase) fluid within the conditions investigated. At flow reference temperature, Tref = 30 °C, the pressure drop obtained from emulsion with 30% water content was 931 Pa, compared to 84.6 Pa which was obtained from 50% water content (i.e. reference fluid without NaCl). In addition, the pressure drop of 239 Pa, 142 Pa, 124 Pa, and 82.9 Pa was obtained from O/W emulsion samples containing 70000 ppm, 40000 ppm, 20000 ppm, and 10000 ppm salinity in the aqueous phase, respectively. Furthermore, the maximum dynamic viscosity imposed by the fluid, was calculated as ≈81000 cP for the sample containing 30% water content compared to ≈14000 cP from the reference fluid. The dynamic viscosity obtained from 70000 ppm salinity content was ≈34000 cP compared to ≈20000 cP, ≈16000 cP, and ≈13000 cP calculated for 40000 ppm, 20000 ppm, and 10000 ppm salinity, respectively. Moreover, large reduction in pressure drop (99%) and dynamic viscosity (60–90%), regardless of the water content and salinity were obtained from the simulation.