低含油条件下烷基季铵盐类化合物的水合物防聚机制和性能

Mechanisms and performance of hydrate anti-agglomeration with quaternary ammonium at low oil content

利用十六烷基和十二烷基三甲基溴化铵(HTAB、DTAB)作为水合物防聚剂,通过搅拌式试验装置研究其在低含油条件下的水合物防聚性能,基于含油量、过冷度、水相转换率对防聚效果的影响,分析其防聚机制。结果表明在无油相条件下质量分数为1%的HTAB能加速水合物的生成,使水相转换率(质量分数)从29.7%提高到54.2%,最终形成致密的块状水合物;1%HTAB体系中加入体积分数为22.2%的煤油时,最终72.89%的水转换成水合物,但水合物呈松散颗粒状,不聚集,具有良好的防聚作用,且不受过冷度的限制;HTAB分子碳链的亲油性能使油膜覆盖于水合物颗粒表面,从而抑制颗粒的聚集;HTAB促进水转换成水合物,使体系中煤油含量相对增加,进而促进体系转变成油包水乳状液,发挥更好的防聚效果。

The hexadecyl trimethyl ammonium bromide(HTAB)and dodecyl trimethyl ammonium bromide(DTAB)were used as anti-agglomerants to study their hydrate anti-agglomeration performance at low oil content by a stirring hydrate reaction apparatus.The anti-agglomerant mechansm was analyzed on the basis of the influence of oil content,subcooling,and water conversion rate.The experimental results show that 1.0%(mass fraction)HTAB without oil accelerates the hydrate formation,increases the water conversion rate(mass fraction)from 29.7%to 54.2%,and finally forms a dense clumpy-like hydrate.When 1%HTAB aqueous solution is added with 22.2%(volume fraction)kerosene,it can form powder-like hydrate without deposition,and show good hydrate anti-agglomeration performance without limits of the subcooling.The hydrophilic head-group of HTAB molecules can absorb on the hydrate particles surface,and promote the oil cover the particles and provide steric repulsion among the particles to anti-agglomeration.Besides,HTAB can accelerate more water conversion to be methane hydrae and the relative oil content is increased in the mixed system,which leads to the transfer of the system to be water-in-oil emulsion and exerts a better anti-aggregation effect.