添加水合物促进二氧化碳水合物生成的实验研究

Experimental Study on Formation of CO_2 Hydrate with Hydrate Additive

水合物法分离、封存二氧化碳,是减少温室气体排放的有效方法之一。今在专门设计的水合物形成实验装置上,研究了二氧化碳水合物初始生成相平衡条件及其影响因素。分别在纯水中加入2.5%、6%和12.5%体积比的水合物晶块进行水合物的生成实验,发现当加入量为6%体积比以上时,不但可以缩短水合物初始形成时所需要的诱导时间,还可以大大降低过冷度,最低可使其在接近相平衡点的状态下生成水合物。而当加入量为2.5%体积比时,与未加入时相同,没有降低过冷度或缩短诱导时间的作用。本研究结果可用于缩短水合物生成时的诱导时间和降低装置的耐压极限,并提示为防止天然气管道中的水合物的重复堵塞问题,应尽可能彻底清除管道中的水合物残余物。

The separation and storage of CO2 by hydrate method is an effective way to reduce the greenhouse gas emission into the atmosphere.Based on a special designed apparatus for the formation of hydrate,the initial formation conditions of CO2 hydrate and the factors affecting the formation were investigated.In this study,the previously prepared CO2 hydrate of 2.5%（vol）,6%（vol） and 12.5%（vol） were added respectively into the pure water to study the formation of CO2 hydrate.It shows that,when the added amount of previously formed CO2 hydrate crystal is over 6%（vol）,the needed degree of supercooling and the induction time for the initial formation of the CO2 hydrate in the pure water can be considerably decreased,while when the addition of previously prepared CO2 hydrate crystal into the pure water is 2.5%（vol）,it will have no effect on the initial formation conditions of the hydrate,which are the same as those for the pure water without adding previously prepared CO2 hydrate.These results can be used to reduce the induction time for the formation of the CO2 hydrate and lower the operation pressure of the hydrate formation apparatus.Besides,the results also show that the hydrate crystals in the nature gas pipeline should be cleaned out thoroughly to prevent the repeated blockage of the pipeline.