含蔗糖体系CO_2水合物生成过程和相平衡的实验研究

Experiment alstudy of CO_2 hydrate formation and phase equilibrium in the system with sucrose inhibitor

气体水合物堵塞风险的防治是油气开采安全保障的重要工作,添加抑制剂是预防水合物生成的有效手段。采用蔗糖作为抑制剂,利用可视化高压反应釜实验装置,实验的温度范围为-0.5~4.8℃和压力范围为1.11~3.0MPa,研究了添加质量分数为5%、10%、15%、20%和25%的蔗糖对CO_2水合物生成过程和水-水合物-气三相相平衡的影响,并分析了蔗糖体系中CO_2水合物生成的微观机理。实验结果表明蔗糖对CO_2水合物生成有抑制作用且改变了相平衡条件,实验中蔗糖抑制效果最佳的质量分数为25%,相比蒸馏水体系的总压降减少了29.3%,气体消耗量减少了68.76%。蔗糖抑制水合物生成的微观机理主要是由于其分子的多羟基结构减少了体系中的自由水的量,降低了体系的水活度,改变了相平衡条件。以蔗糖作为水合物抑制剂效果良好,且经济环保。

The prevention of gas hydrate plugging is an important work in the safety of oil and gas exploration,and the use of inhibitors is an effective means to prevent hydrate formation.In this experiment,the effects of sucrose（mass fraction of 5,10,15,20 and 25%） as hydrate inhibitor on CO2 hydrate formation and three-phase equilibrium conditions of liquid water-hydrate-vapor were investigated by using the visualized high pressure reactor at-0.5~4.8℃ and 1.11~3.0 MPa.Furthermore,its microscopic mechanism of inhibiting hydrate formation was analyzed.The results show that the sucrose has significant effect on inhibiting the hydrate formation and can change the three phase equilibrium.The optimized mass fraction of sucrose is 25%.Compared with the formation of CO2 hydrate in distilled water,the pressure drop decreases 29.3% and the gas consumption decreases 68.76%.The inhibition mechanism is chiefly that the multi-hydroxyl structure of sucrose decreases the content of free water and the activity of water in system and changes the conditions of three phase equilibrium of system.The sucrose has a good inhibition effect as well as economy and environmental friendly as a hydrate inhibitor.