水合物合成及导热系数测定

设计了一套实验装置，结合瞬态面热源法来测量混合气水合物导热系数及含混气水合物的沙子多孔介质的有效导热系数.在-10℃～5℃，压力66MPa下，含体积比甲烷9001%，乙烷503%，丙烷496%的混合气与0971mol/m3十二烷基磺酸钠水溶液生成的水合物的导热系数约为055W/(m·K)，并且其值随温度的上升而增高，呈玻璃体导热特性.由于“爬壁”效应的存在，混合气与饱含SDS水溶液的沙子多孔介质反应生成含混合气水合物的沙子多孔介质的有效导热系数（约12W/(m·K)）显著低于含四氢呋喃水合物的沙子多孔介质的值（约19W/(m·K)）.虽然本实验使用了SDS来加速和促进水合反应的进行，但是水合物样品中依然存在游离水，因此本研究采用了温度振荡法来进一步促进含SDS水溶液的水合反应进行，研究发现当浴槽温度在-10℃～4℃间周期变化时，游离水在水的相变温度区附近转变为水合物，通过几个周期的温度振荡，样品中的游离水被完全消耗掉.最后通过对含不同浓度SDS的四氢呋喃水合物导热系数测试，讨论了实验中加入SDS对水合物导热系数的影响，结果认为本实验中加入的SDS量对测试结果影响很小（±15%）.

Measurements of gas hydrate composition and its thermal conductivity

An experiment apparatus has been constructed to measure thermal conductivity of composite gas hydrate and gas hydrate sand mixtures. The composite gas hydrate formed from the combination of gas (methane 9001 volume %, ethane 503 volume % and propane 496 volume %) and 0971 mol/m3 aqueous sodium dodecyl sulfate (SDS) solution has a thermal conductivity around 055 W/(m·K) from -10℃ to 5℃ and at 66MPa. The hydrate's thermal conductivity dependent on temperature shows glass like, grows with increasing temperature. However, the measured 12 W/(m·K) effective thermal conductivity (ETC) of the composite gas hydrate bearing sand is significantly lower than that of tetrahydrofuran (THF) hydrate bearing sand (about 19W/(m·K)). This is because the hydrate formed with a SDS solution in sand at our laboratory has a “wall creeping" growth characteristic and consequently a large part of the pores were filled with free gas. In order to obtain well characteristic hydrate samples for measurement, this work uses a method to promote the reaction of SDS solution and gas. When the temperature changes in the range from -10℃ to 4℃, it is found that the stagnated reaction reacts again in the zone of phase change temperature of water. And the surviving water could be consumed out after several vibration periods. The SDS's effects on the measurement are also discussed based on experiments. We think that the SDS concentration used in this work has a minor effect on the hydrate's thermal conductivity, and it only causes a deviation of ±15%.