蔗糖和凹凸棒石体系下抑制CO_2水合物生成动力学研究

Kinetic Study of Carbon Dioxide Hydrate Formation in Presence of Sucrose and Attapulgite

油气生产、储运及CO_2管道输送的过程中容易生成CO_2水合物,添加抑制剂是预防CO_2水合物生成的有效手段。采用蔗糖、凹凸棒石和蔗糖+凹凸棒石作为水合物抑制剂,利用可视化高压反应釜实验装置,在初始条件3 MPa和2℃下,研究其对CO_2水合物生成的气体消耗量、气体消耗速率、诱导时间和水合物生成量的影响。用压力变化法测定了CO_2水合物生成诱导时间,用动力学模型计算了气体消耗量和水合物生成量;并分析了蔗糖和凹凸棒石协同抑制CO_2水合物生成的微观机理。实验结果表明蔗糖有减少气体消耗量和水合物生成量的作用,凹凸棒石有延长水合物生成诱导时间和降低生成速率的作用,体系中同时存在蔗糖和凹凸棒石能展现出协同效应,抑制效果最佳的实验体系为30 g蔗糖+1 g凹凸棒石,较纯水体系的气体消耗量减少了18.8%,气体消耗速率峰值降低了60.9%,诱导时间延长了122.2%,水合物生成量减少了26.1%。以蔗糖+凹凸棒石作为水合物抑制剂效果良好,且经济环保。

Oil and gas production,storage and transportation and CO_2 transport via pipelines easily form CO_2 hydrate. The most effective method is inhibitor addition. In this connection,an experimental study was conducted of CO_2 hydrate formation. In this experiment,the effects of sucrose and attapulgite on CO_2 hydrate formation induction time,gas consumption rate,amount of gas consumption and gas hydrate formation were investigated by using the high-pressure reactor. The experiments were conducted at temperatures 2 ℃ and initial cell pressures 3 MPa.The formation and induction time by changing pressure was measured and calculated the gas consumption and production of hydrate by the kinetic model. And the inhibiting mechanism of sucrose and attapulgite on CO_2 hydrate formation was analyzed from the micro perspective. It is shown that sucrose can reduce the gas consumption and production of hydrate,and attapulgite can increase the induction time as well as reduce generating rate. The mechanisms of the synergistic effects when use the sucrose and attapulgite together were analyzed. The results showed that adding 30 g sucrose and 1 g attapulgite has the best inhibiting effect. Compared with the gas consumption of CO_2 hydrate in deionized water,the gas consumption decreases 18. 8%,and the peak gas consumption rate reduces60. 9%,the induction time increases 122. 2%,the production of hydrate in sucrose and attapulgite system is26. 1% shorter than that in deionized water. As a result,the sucrose and attapulgite as composite hydrate inhibitor has a good inhibitory effect. In addition,it is economical and environment-friendly.