Thrane Linn W, Seymour Joseph D, Codd Sarah L
Department of Mechanical and Industrial Engineering, Montana State University, Bozeman, MT 59717, United States.
Department of Chemical and Biological Engineering, Montana State University, Bozeman, MT 59717, United States.
J Magn Reson. 2019 Jun;303:7-16. doi: 10.1016/j.jmr.2019.04.003. Epub 2019 Apr 4.
High-field nuclear magnetic resonance (NMR) relaxometry and diffusometry along with magnetic resonance imaging were used to monitor phase transition molecular dynamics during hydrate formation occurring in water droplets dispersed in liquid cyclopentane. 1D T relaxation measurements indicate the extent of hydrate formation as well as a reduction in water droplet size with progression of hydrate growth. MRI intensity maps and T relaxation maps indicate spatially dependent hydrate formation rates due to the heterogeneity of the system. Spectrally resolved diffusion measurements indicate a reduction in the porosity of the hydrate agglomerate as the hydrate shell increases in thickness. A novel signal rise observed in two dimensional T-T relaxation correlation experiments indicates complex diffusion dynamics due to coupling between regions with varying relaxation and diffusion. These results indicate the ability to monitor hydrate growth and phase transition molecular dynamics due to evolution of the porous hydrate agglomerate by means of high-field NMR.
高场核磁共振（NMR）弛豫测量和扩散测量以及磁共振成像被用于监测在分散于液态环戊烷中的水滴中发生水合物形成过程中的相变分子动力学。一维T弛豫测量表明水合物形成的程度以及随着水合物生长进程水滴尺寸的减小。MRI强度图和T弛豫图表明由于系统的不均匀性，水合物形成速率存在空间依赖性。光谱分辨扩散测量表明随着水合物壳层厚度增加，水合物聚集体的孔隙率降低。在二维T-T弛豫相关实验中观察到的一种新的信号增强表明由于具有不同弛豫和扩散的区域之间的耦合导致了复杂的扩散动力学。这些结果表明借助高场NMR能够监测由于多孔水合物聚集体的演化而产生的水合物生长和相变分子动力学。
