关键词: 凹凸棒石, CO₂水合物, 抑制生成, 微观机理

Abstract: CO₂ hydrate is often formed in oil and gas production, storage and transportation, and CO₂ transporting via pipelines. The most effective method to prevent CO₂ hydrate is to add inhibitor. To solve the problem of CO₂ hydrate blockage, the effects of ultrasonic processing attapulgite, as a hydrate inhibitor,(mass concentration of 0, 0.05mg/mL, 0.30mg/mL, 0.50mg/mL, 0.75mg/mL, 1.00mg/mL and 1.50mg/mL) on the kinetics of CO₂ hydrate formation were investigated by using the high-pressure reactor. The experiments were conducted at temperatures 2℃ and initial cell pressures 3MPa. The impacts of various concentrations of attapulgite on CO₂ hydrate formation were studied. The induction time and the generated quantity were measured by changing pressure. The production of hydrate was calculated by the kinetic model. Furthermore, the microscopic mechanism of inhibiting hydrate formation was analyzed. The results showed that the suspension of attapulgite had significant effect on inhibiting the formation of hydrate. The optimal concentration is 0.75mg/mL. Compared with the formation experiment of CO₂ hydrate in deionized water, the induction time increased by 200%; the hydrate formation would be reduced in the attapulgite system, which can be decreased by 12.8% at the optimal concentration of 1.5mg/mL. The inhibition mechanism of attapulgite is mainly due to its selective adsorption and blocking mass and heat transfer. Therefore, the attapulgite, as a new CO₂ hydrate inhibitor, has a good inhibitory effect as well as economy and environmental friendly.

Key words: attapulgite, CO₂ hydrate, inhibit formation, microscopic mechanism