添加剂对CO2水合物生成的影响

EFFECT OF ADDITIVES ON THE FORMATION OF CARBON DIOXIDE HYDRATE

以水合物的方式分离/储存CO2气体是一项具有挑战性的新技术。为了提高水合物的生成速率和储气密度,在小型可视化的水合物反应装置上实验研究了不同种类的添加剂对CO2水合物生成特性的影响。结果表明,实验用有机硅系列添加剂可以有效降低气—水界面的表面张力,提高水合物的生成速率。CO2水合物的生成量随着添加剂浓度的增大而增大,但当浓度高于0.1%以后,其生成量增长非常缓慢。单组分添加剂SilwetL-77效果最好,而单组分添加剂THF对CO2水合物的生成没有任何改善,但将浓度为4%的THF和1%的SilwetL-77混合后却对水合物的生成起到了显著的改善效果,12h内的气体压降可达到0.27MPa,是纯水体系的10倍之多,照片显示有大量的水合物生成。研究结果对寻找适合于CO2水合物快速生成的添加剂,为其应用于高效分离储存CO2气体技术等方面提供了指导。

It is a challenging technique to capture,separate and storage CO2 by means of gas hydrate. In order to increase the hydrates formation rate and the storage capacity,experimental study on the effect of different additives on CO2 gas hydrate formation was carried out with a visual and high-pressure test cell. It shows that the Silwet additives can effectively reduce the interfacial tension of gas water contact and accelerate the rate of gas hydrate formation. The hydrate formation rate is increased along with the increase of the additive concentration,but it is not evident as the additive concentration is more than 0.1%,the surfactant Silwet L-77 shows most effective for CO2 hydrate formation,while THF shows no improvement effect on CO2 hydrate formation. However,the mixture of Silwet L-77 in concentration of 1% and THF in concentration of 4% can promote the hydrate formation rate considerably,the pressure drop reaches up to about 0.27Mpa within 12 hours which is about ten times of that without additives,and the photo shows a large amount of hydrates formed in the cell. The research work can provide significant guidance to choose an effective additive for CO2 separation and storage.