Span20促进甲烷水合物生成的实验研究

Experimental Investigation on Span20 Promoting Effect on Methane Hydrate Formation

在已有的天然气水合物储气实验台上，利用带磁力搅拌的141 mL高压反应釜，采用定压法，在温度为（274.15±0.10）K、压力为（8.30±0.10）MPa的条件下，从诱导时间、生成速率和储气密度等方面研究了非离子表面活性剂失水山梨醇单月桂酸酯（Span20）的质量分数为0～3%范围内对甲烷水合物生成的影响。结果发现：Span20的质量分数为0.2％时诱导时间最短，为53～167min；在0.4%时的生成速率最大，是纯水的10倍以上，同时其储气密度V／Vo最大，达到145.2。通过分析Span20的分子结构，对表面活性剂促进甲烷水合物形成机理进行了研究，认为可能是Span20分子中带有2个羟基的类四氢呋喃结构的诱导作用以及假六元环的模板作用共同促进了甲烷水合物的形成。

Experiments on the effect of non-ionic surfactant sorbitan monododecanoate （Span 20） on induction time, formation rate and gas storage density were conducted during methane hydrate formation in a high pressure reactor with a magnetic stir at （274. 15±0. 10） K, （8. 30±0. 10） MPa and 0-3%. The results show that the induction time with 0. 2% Span 20 was shortest, 53- 167 minutes and a maximum formation rate was obtained with 0. 4% Span 20, about 10 times the rate of pure water. Moreover, at 0. 4% Span 20 also had the largest gas storage density of 145.2. On the basis of analysis on the Span 20 structure, the mechanism of surfactants promoting methane hydrate formation was investigated. It appears that the induction effect of tetrahydrofuranoid with two hydroxyls together with the template effect of the false hexahydroxy cycle may promote methane hydrate formation.