表面活性剂的酸碱度对甲烷水合物生成的影响

Effect of acidity and alkalinity of surfactants on methane hydrate formation

针对甲烷水合物的快速制备,在初始压力7MPa和恒温2℃条件下采用脂肪醇聚氧乙烯醚硫酸钠(AES)阴离子表面活性剂和烷基多糖苷(APG1214)非离子表面活性,通过改变表面活性剂溶液的酸碱性,观察不同pH值对水合物的促进能力,并以表面活性剂分子吸附理论为基础进行分析。结果表明,在pH=3强酸条件下,水合物在气-液界面处先形成晶核,阻碍了气液继续接触,储气密度最低;在pH=11强碱性条件下,晶核在固-液界面处成核,水合物生成速率最高,储气密度最大。

In order to rapid prepare methane hydrate, anionic surfactant aliphatic alcohol polyethoxylate sulfates (AES) and nonionic surfactant alkyl polyglycoside (APG1214) were used under initial pressure of 7 MPa and constant temperature of 2 ℃. Promotion of hydrate formation under different pH values was observed by altering acidity and alkalinity of surfactant solutions, and the results were analyzed based on the theory of molecular adsorption of surfactants. The results show that the hydrate forms crystal nucleus at the gas-liquid interface under pH = 3, which hinders continuous gas-liquid contact and shows the lowest gas storage capacity. Crystal nucleus forms at the solid-liquid interface under pH = 11 with the highest hydrate formation rate and the highest gas storage capacity.