Study On The Formation Of Natural Gas Hydrate Under The Complex System Of Porous Media And Surfactants

With the continuous optimization of China's energy structure,natural gas plays an increasingly important role in people's daily life.As a kind of high quality natural gas carrier,natural gas hydrate has been paid more and more attention by scholars.However,under natural conditions,the formation of NGH is extremely slow,and how to quickly and efficiently generate NGH is the key to the industrial utilization of NGH,so the research on the formation of NGH is extremely urgent.In order to study the NGH formation mode under the mixed system of different silica products and SDS solution,four kinds of silica products were mixed with SDS solution at different concentrations to conduct NGH formation experiment.In order to further explore the influence of solution tension and capillary force on the formation pattern of NGH,the complex system of resin and surfactant was used for the formation experiment of NGH.Then,in view of the influence of surface characteristics of porous media on the formation of NGH,SDS?SDBS and BS-12 surfactants were selected and compounded with activated carbon respectively to study the formation of NGH.The results show that the formation modes of NGH in different silica products and SDS solution complex systems are quite different,but they all follow the Growth theory of Kessel-Stranski crystal layer.The solution surface tension and capillary forces act together on the migration of water molecules so as to change the formation position of NGH.It is also found that the induction time of NGH affects the size of crystal particles.The longer the induction time is,the more crystal nuclei are formed and the smaller the grains are.The concentration of 200 ppm silica-SDS solution system is more suitable for the industrial preparation of NGH.It is found that the difference between the generation of bar-shaped NGH and that of each system is the result of the joint action of capillarity and the polarity of the resin.The stronger the polarity of the resin is,the more the formation of bar-shaped NGH inside the reactor will be.Also activated carbon surface chemical properties of surfactant molecules has obvious selective adsorption,chemical groups of solute molecules adsorbed on the surface of the activated carbon has obvious differences,such differences as a result of the specific performance in the combination of natural gas hydrate and activated carbon intensity and the change of system pressure,the adsorption of activated carbon to BS-12 is the strongest,and the pressure change is the greatest;the adsorption of activated carbon to SDBS is the weakest,and the pressure change is smaller.