The detection of tetrahydrofuran hydrate formation and saturation using magnetic resonance imaging technique

Tetrahydrofuran（THF） hydrate was formed in bulk as well as in glass beads pack with a mean diameter of 3.0 mm by controlling the temperature under ambient pressure.Images of THF hydrate formation procedure were obtained using the magnetic resonance imaging（MRI） technique.The experiment results showed that MRI is an effective method for the detection of hydrate formation.Saturation of hydrate formed both in bulk and glass beads can be confirmed by intensity integration of MRI images.

Microscopic morphology evolution of the crystal structure of tetrahydrofuran hydrate under flowing condition

The evolution of the hydrate particle structure during growth and agglomeration under flowing condition affects the particle as well as flow characteristic,which plays an important role in the flow assurance as well as heat transfer in refrigeration systems.Therefore,this article conducts experiments to study and observe the growth and agglomeration process in the main forming stage of hydrate.It was found that the growth of tetrahydrofuran hydrate was anisotropic and in a layered growth pattern.Single crystals generally transformed from octahedral structure to octahedral skeleton structure with growth,however some single crystals also deformed into plate type particles.The thickness of the plate type particles increased gradually during growth,and the edge part increased earlier than the middle part.During agglomeration,the hydrate particles contacted and sintered together.Sand as the impurity didn’t serve as the nucleation center but affected the agglomeration of hydrate particles by collisions.In addition,the effect increased as the sand size decreased.Finally,a microstructure model for hydrate growth and agglomeration was proposed,which showed the hydrate structure evolution in these processes and could lay a foundation for studying the flow assurance of hydrate slurry.

Accelerated nucleation of tetrahydrofuran(THF)hydrate in presence of ZIF-61

Clathrate hydrate can be used in energy gas storage and transportation, CO2 capture and cool storage etc. However, these technologies are difficult to be used due to the low formation rate and long induction time of hydrate formation. In this paper, ZIF-61 （zeolite imidazolate framework, ZIF） was first used in hydrate formation to stimulate hydrate nucleation. As an additive of clathrate hydrate, ZIF-61 promoted obviously the acceleration of tetrahydrofuran （THF） hydrate nucleation. It shortened the induction time of THF hydrate formation from 2-5 h to 0.3-1 h mainly due to the template function of ZIF-61 by which the nucleation of THF hydrate has been promoted.