The hydrate cell with microscope and Raman setup is used to observe hydrate micro morphologies and phase transitions in micro pores.
Detailed description
The setup has a 2D rectangular microfluidic chip with the operation pressure up to 100 bar. The volume of microfluidic chip is 10µl and it has three types of micro pores, i.e. random type, uniform type and physical rock type.
The fluid in micro pores of chip is manipulated by two Vindum pumps controlling two piston containers. The chip is fixed in a micromodel containing a chamber of two aluminium frames.
The micromodel is completely submerged in glycol circulating to control temperature. Temperature in glycol is controlled by a cooling bath circulating antifreeze in a jacket.
Gas/water is injected from piston containers up to 60-80 bar controlled by Vindum pumps. Gas/water mixing is achieved in field of view by adjusting pressures of Vindum pumps.
Agitation by opening and closing outlet in a few seconds to create gas/water interface in necessity.
Hydrate formation between gas (guests) and water (host) is achieved by decreasing temperature from room temperature of 20℃ to low temperature of 1-4℃. A pressure difference between two ports of chip is an indicator of blockage due to hydrate formation.
A stereomicroscope equipped with a Canon camera is employed to directly visualize and continuously record real-time phase transition of hydrate formation in micro pores.
An in-situ Raman device is used to determine the guests in gas phase, water phase and hydrate phase.
In case of no hydrate formation, temperature is increased to 20℃. A total three cycles of cooling and heating, known as the annealing process, are employed to promote gas/water distribution and induce hydrate formation in micro pores.
A schematic of hydrate cell with microscope and Raman setup.
Publication
Ouyang, Qian, Jyoti Shanker Pandey, and Nicolas von Solms. "Microfluidic insights: Methane hydrate dynamics in distinct wettable confined space." Chemical Engineering Journal 474 (2023): 145567.