Methane concentrations from gas hydrate dissolution laboratory experiments

This dataset reports methane concentrations from nine hydrate dissolution laboratory experiments. Experiments were conducted in a 600 mL stainless steel, bench top, cylindrical pressure chamber over 20 days. To form hydrate quickly, we utilized the surfactant sodium dioctyl sulfosuccinate (SDS). The chamber was filled with ~ 350 mL SDS- water and temperature was brought down to between 0 and 2˚C in the fridge. Hydrocarbon gases, either propane or methane, were introduced to the chamber using a needle valve. Using the source gas, the chamber was brought up to between 3 and 6 MPa pressure and the hydrate formed at the gas-water interface. Once hydrate was formed, it was flushed with a solution of 380 ppm SDS in distilled water, the headspace was flushed with nitrogen, and water samples were collected to determine the dissolution rate. Water samples were collected through a port interfaced to the bottom of the chamber with a needle valve. The needle valve was opened to a 6-port sampling valve with a 1 mL sample loop that opened to 20 mL gas tight syringe. Typically 1 mL of water and several milliliters of gas were collected. Samples were diluted to 20 mL total value with helium, and methane was extracted from the water by headspace equilibrium. Headspace methane concentrations were measured using a Gas Chromatograph– Flame Ionization Detector (GC-FID). This data can be used to calculate dissolution rates over time.本数据集记录了9项水合物溶解实验室实验的甲烷浓度数据。实验在容量600 mL的台式圆柱形不锈钢压力舱内开展，周期为20天。为快速制备水合物，我们使用了表面活性剂二辛基磺化琥珀酸钠（SDS）。向舱内注入约350 mL的SDS水溶液，随后将装置放入冰箱降温至0~2℃。通过针型阀向舱内通入烃类气体（丙烷或甲烷），以气源将舱内压力升至3~6 MPa，水合物随即在气液界面处生成。水合物成型后，先用380 ppm的SDS蒸馏水冲洗舱体，再以氮气吹扫顶空空间，随后采集水样以测定溶解速率。水样通过连接至舱底的端口采集，该端口配有针型阀；该针型阀与带有1 mL定量环的六通进样阀相连，六通阀外接20 mL气密注射器。通常单次采集1 mL水样与数毫升气体。将样品用氦气稀释至总容积20 mL，通过顶空平衡法从水中萃取甲烷。采用气相色谱-火焰离子化检测器（GC-FID）测定顶空甲烷浓度。本数据集可用于计算随时间变化的溶解速率。