CO2 hydrate nucleation study: novel high-pressure microfluidic devices†

This study presents the development and application of a novel high-pressure microfluidic system for investigating CO₂ hydrate nucleation and growth, with applications for carbon capture and storage (CCS) technologies. Two distinct microchip geometries—a capillary channel chip (serpentine-shaped) and an advanced droplet trap chip— were respectively designed and evaluated. These microchips enable the generation, trapping, and observation of CO₂ droplets or bubbles within aqueous systems under static and dynamic conditions. The capillary channel chip allows droplet storage in a single serpentine channel, whereas the droplet trap chip offers superior immobilization and control, preventing droplet/bubble displacement during CO₂ hydrate formation. High-resolution optical imaging, coupled with precise pressure and temperature regulation and control, facilitated real-time visualization of CO₂ hydrate crystallization at CO₂–water interfaces under varying temperature and pressure conditions. Experimental results reveal the influence of geometry, flow dynamics, and hydrodynamics on hydrate morphology and growth. The high-pressure microfluidic setup provides an adaptable and scalable approach for studying hydrate behavior, offering valuable insights for investigating CO₂ storage in geological formations.