Abstract: Under natural conditions, natural gas hydrates are found in marine environments. Therefore, it is necessary to study the formation of hydrates under salt water conditions and their basic properties. The effect of low⁃concentration MgSO4 with sodium dodecyl sulfate (SDS), alkyl glycoside (APG), dodecyl trimethyl ammonium chloride (DTAC) and other surfactants on the formation of hydrates was studied. The changes of pressure and temperature with time during the formation of hydrate were measured under the conditions of 275.15 K and 6 MPa. The results show that when a certain concentration of SDS or APG is added to the solution, the hydrate formation is significantly promoted. When a certain amount of DTAC is added, substantially no hydrate is formed in the solution. Furthermore, low concentration of MgSO4 significantly enhanced the promoting effect of surfactants. It can be seen that low concentration of MgSO4 and appropriate concentration of surfactant will promote the formation of methane hydrate, and different types of surfactants have different effects on the formation of hydrate. Compared with the promotion effect of SDS and APG on hydrate formation, the promotion effect of DTAC on hydrate formation is not obvious.

Key words: Hydrate, Surfactant, Salts, Gas consumption

摘要： 在自然条件下，天然气水合物多存在于海洋环境中。因此，研究盐水条件下水合物的形成及其基本性质很有必要。研究了低浓度的MgSO₄与十二烷基硫酸钠（SDS）、烷基糖苷（APG)、十二烷基三甲基氯化铵（DTAC）等不同表面活性剂复配对水合物生成的影响。在275.15 K、6 MPa的环境下，考察了水合物形成过程中压力和温度随时间的变化。结果表明，当溶液中加入一定浓度的SDS或APG时，会显著促进水合物的生成；当加入一定量的DTAC时，溶液中基本不生成水合物；低浓度MgSO₄会显著增强表面活性剂的促进作用。由此可知，低浓度的MgSO₄和适当浓度的表面活性剂都会促进甲烷水合物的生成，不同类型的表面活性剂对水合物生成的影响不同。相比于SDS、APG，DTAC对水合物生成的促进效果并不明显。

关键词: 水合物, 表面活性剂, 盐, 耗气量