利用氧化石墨烯促进CO_2水合物的生成

Graphene Oxide Enhanced the Formation of CO_2 Hydrate

气体水合物高效快速生成是实现水合物技术工业应用的关键问题。为解决水合物生成速率慢、储气能力低等难题,利用高压反应釜实验装置,研究了质量浓度为20、35、50、100、200、300 mg/L的氧化石墨烯对CO_2水合物生成过程温压变化规律、生成时间和诱导时间及气体消耗量的影响,并与纯水体系中水合物生成实验进行了对比和分析。结果表明,氧化石墨烯促进CO_2水合物生成的最佳浓度为50 mg/L,在该浓度下反应体系的终态压力最低,压力降低的幅度达1.731 MPa;且与纯水体系相比,水合物生成诱导时间缩短了77.14%,反应周期缩短了1/2,气体消耗量提高了15.89%。从微观角度分析了氧化石墨烯促进CO_2水合物生成的作用机理,其独特的单层分子结构及表面丰富的氧基功能团使其具有纳米颗粒级别的高比表面积、具有优良的传热传质及亲水特性;能够促进气体溶解、增加水合物成核点、提高成核速率;加快体系热量传递、平衡系统温度;能够加快传质速率、增加气体消耗,提高储气能力。

The efficient and rapid hydrate formation is the key to realize the large-scale industrial application of hydrate technology. In order to improve the formation rate and gas storage capacity of hydrate,the effect on CO_2 hydrate formation characteristics in graphene oxide solution of 20、35、50、100、200、300 mg / L was studied experimentally in a high pressure reaction kettle device. The changing rules of temperature and pressure of CO_2 hydrate formation,and the influence on formation time,induction time and gas consumption with graphene oxide were investigated,which were compared with pure water system. The results showed that the best promote concentration of graphene oxide was 50 mg / L. Under the concentration of 50 mg / L,the final pressure reached to the lowest relatively,the pressure was reduced by 1. 731 MPa. And compared with pure water,the induction time of hydrate formation shortened by 77. 14%,the reaction period shortened by 1 /2,the gas consumption increased by 15. 89%. And the promoting mechanism of graphene oxide on CO_2 hydrate formation was analyzed from the micro perspective,the graphene oxide has good heat and mass transfer properties of nanoparticle level and the hydrophilic property because of its unique molecular structure as the single layer with abundant functional groups on the surface. The advantages included the ability to promote the dissolution of gas,and increase the nucleation rate; to speed up the heat transfer efficiency and balance the system temperature; to accelerate the mass transfer efficiency,to increase the gas consumption and improve gas storage capacity.