Maeda Nobuo
CSIRO Materials Science and Engineering, Ian Wark Laboratory, Bayview Avenue, Clayton, VIC 3168, Australia.
Rev Sci Instrum. 2013 Jan;84(1):015110. doi: 10.1063/1.4774051.
We previously reported the development of a high pressure automated lag time apparatus and a high pressure video cell for experimental study of nucleation and growth of gas hydrates. Here we report the development of a high pressure electrical conductivity probe that monitors the electrical conductivity of an electrolyte that is subjected to a linear cooling ramp at elevated hydrate-forming-gas pressures. The electrical conductivity steadily decreases as the linear cooling progresses because of the increasing viscosity of the electrolyte and the consequently decreasing mobility of the ions. The onset of the formation of methane-propane mixed gas hydrate films at the gas-electrolyte interface is marked by an upward spike in the electrical conductivity. The physical mechanisms behind this phenomenon remain to be elucidated. Continued cooling of the electrolyte to, and subsequent holding of, the temperature at 273 K eventually results in decreased electrical conductivity. This conductivity signal can be used for the detection of the onset of the formation of gas hydrates in optically opaque samples that contain electrolytes.
我们之前报道了一种用于气体水合物成核与生长实验研究的高压自动滞后时间装置和高压视频池的研制情况。在此，我们报告一种高压电导率探头的研制情况，该探头可监测在升高的水合物形成气体压力下经历线性冷却斜坡的电解质的电导率。随着线性冷却的进行，由于电解质粘度增加以及离子迁移率相应降低，电导率会稳步下降。在气 - 电解质界面处甲烷 - 丙烷混合气体水合物膜形成的起始点以电导率的向上尖峰为标志。这一现象背后的物理机制仍有待阐明。将电解质继续冷却至273K并随后保持该温度最终会导致电导率降低。这种电导率信号可用于检测含有电解质的光学不透明样品中气体水合物形成的起始点。
