Generation of high-viscosity heavy oil droplets: Insights from image analysis and numerical simulation

Abstract

To understand the behavior of high-viscosity heavy oil droplets generated in mass transfer systems, a method was established to measure the microdroplet formation via image analysis, with measurement errors controlled within 10 %. N-dodecane–dimethicone solutions with different viscosities and ethanol–deionized water solutions were employed as dispersed and continuous phases, respectively. The study identifies three stages of microdroplet formation: shrinkage, expansion, and fracture. The pressure and velocity fields during the fracture stage are simulated using a numerical simulation method. The fracture stages of droplets are categorized into three morphologies: fluctuating fracture, equilibrium fracture, and hysteretic fracture, which can be predicted using the Re number and We number. Increasing the viscosity of the dispersed phase increases the droplet formation time. The volume of produced droplets increases as the n-dodecane content in the dispersed phase increases. Finally, the droplet size decreases with an increase in the microdroplet formation time and a decrease in the nozzle size. Experimental results reveal the formation of high-viscosity heavy oil droplets in strong mass transfer solvents and offer prospects for developing micro-reaction technology for heavy crude oil refining.