(702e) A Microfluidic Droplet Platform for Investigating Nucleation Kinetics of Hydrocarbons for Application to Wax Crystallization

Crystallization of wax present in crude oil is a major issue for its storage, processing and transportation. As a result, there is a significant interest in identifying inhibitors that can mitigate the nucleation of wax crystals in crude oil. To address this need, droplet-based microfluidics is used to quantify the nucleation kinetics of n-alkanes - a simple model system for wax. In nucleation studies, it is useful to have control of the droplet volume as it dictates the number of impurities (like dust) present per droplet that can act as nucleation site. Therefore, a valve-based flow-focusing device is used to produce droplets of controllable volume. A downstream storage chamber is included to incubate the produced droplets so that nucleation studies can be conducted. The modular design of the microfluidic system provides flexibility, allowing adjustment to specific experimental requirements. Hexadecane-in-water emulsions are produced using Tween 20 and sodium dodecyl sulfate as surfactants. The effect of droplet size and surfactant type on nucleation rate of n-hexadecane is investigated for the first time in a droplet-based microfluidic platform. The results show that the degree of nucleation in hexadecane could be controlled by selecting an appropriate surfactant and controlling the droplet size. The experimental data is used to test current models of nucleation kinetics. This work will enable establishment of a microfluidic platform for future studies of nucleation in paraffins and their mixtures with inhibitors.