Microfluidic dispersion of mineral oil-seawater multiphase flows in the presence of dialkyl sulfonates, polysorbates, and glycols

The role of dispersants on hydrocarbon phase behavior in seawater is an important problem that influences marine environment ecology. Offshore petroleum and natural gas catastrophes, such as the Deepwater Horizon spill of 2010, motive the need to understand how to minimize the introduction of potentially invasive compounds while maximizing their efficacy during emergency remediation. The microfluidic stabilities of mineral oilseawater multiphase flows in the presence of model dispersants were studied for We < 1. Introducing dispersants at varying dimensionless volumetric injection rates, ranging from 0.001 to 0.01, transitions from stable slug flow to the bubbly regime. Dimensionless mass ratios of three model dispersants to the mineral oil necessary to establish emulsions were estimated from 2.6 × 10^-3 to 7.7 × 10^-3. Residence time distributions of seawater single-phase and mineral oilseawater multiphase flows, laden with dispersants, were also investigated. Increasing the dimensionless dispersant injection rate from 0 to 0.01 was observed to increase convective dispersion, which was confirmed by estimations of the vessel dispersion number and the Bodenstein number. The observations undergird that microfluidics are useful laboratory techniques to identify the transition to bubbly flow where bacteria consumption rates could potentially be enhanced, while minimizing the dispersant mass introduced into calm-sea marine environments.