水合物在静态脂肪醇聚氧乙烯醚硫酸钠溶液与纯水搅拌条件下生成分析

Analysis of hydrate formation in static AES solution and stirring with pure water

促进天然气水合物快速大量生成是天然气水合物技术产业化的关键,因此,对其动力学促进方法进行研究是十分必要的。本文在温度为(2±0.1)℃,压力为(6.6±0.1)MPa条件下研究了不同浓度(60~1350mg/L)脂肪醇聚氧乙烯醚硫酸钠(AES)以及不同搅拌转速0~800r/min对水合物生成的影响,对两种方式的促进效果进行了对比,并从水合物生成动力学角度对AES及搅拌的促进机理进行分析。实验结果表明:AES与搅拌都可以促进液相气过饱和,加速单核生长和多核聚结过程,显著缩短诱导期,提高水合物生成速率及气体消耗量,但不同的是在水合物生长阶段搅拌仅能促进气相向液相单向移动,AES能够使气液交叉移动,显著降低了气液传质阻力,增加了成核位置,因此AES比搅拌进一步提高了水合物生成速率及气体消耗量。

Considering the key role of the rapid and abundant hydrate formation in the industrialization of natural gas hydrate, it is necessary to study the dynamic promoting approaches for hydrate formation In this paper, the effects of AES concentration and stirring rate on hydrate formation were studied experimentally through AES solutions with concentrations from 60mg/L to 1350mg/L and stirring speeds from 0 to 800 r/min at 2℃ and 6.6MPa. The promoting effects were compared, and the promoting mechanisms were studied from the perspective of hydrate formation kinetics, respectively. Results show that both AES and stirring could promote the gas supersaturation in liquid phase and accelerate the growth and coalescence of crystal nucleus. This would significantly shorten the induction period, improve hydrate formation rate, and reduce gas consumption. However, in the hydrate growth stage, stirring could only promote the one-way movement of the gas phase into the liquid phase, whereas AES could improve the cross movements of both gas and liquid phases. This mechanism of AES could reduce the mass transfer resistance between gas and liquid, and significantly increase the nucleation sites. Therefore, AES could further improve the hydrate formation rate and gas consumption.