| As a new type of clean energy,natural gas hydrate has attracted worldwide attention.Domestic and foreign scholars have conducted a series of studies on its composition,physical and chemical properties,thermodynamic characteristics of generation and decomposition,and mining characteristics.Among them,the hydrate saturation parameter plays a very important role in various researches.However,in the simulation experiment at the laboratory scale,due to the adsorption of methane gas by porous media,the calculation result of hydrate saturation will be deviated,which will affect the analysis of experimental results.In this paper,Marine soil,montmorillonite and kaolin were used as porous media to carry out a series of experiments at the laboratory scale to explore the influence of different factors such as temperature,pore pressure,particle size distribution and initial water saturation on methane adsorption characteristics for the remolded samples made by marine soil,montmorillonite and kaolin.Firstly,the effects of different factors on methane adsorption characteristics for the remolded samples made by marine soil were investigated.It was found that the adsorption of methane decreased with the increase of initial water saturation.The temperature was negatively correlated with the adsorption capacity of the sample,and the higher the temperature was,the less obvious the adsorption effect was.The adsorption capacity of methane increased with the increase of pore pressure.Under the action of different particle size distribution,there is no obvious law of methane adsorption in samples of marine soil.Secondly,methane adsorption characteristics for the remolded samples made by montmorillonite clay minerals and kaolin clay minerals under different factors were studied,and the adsorption capacities of the two samples were compared.It was found that with the increase of initial water saturation,the methane adsorption of both clay mineral samples decreased,which was mainly caused by the competitive adsorption between water molecules and methane molecules.At the same time,it was found that the methane adsorption capacity for the samples of montmorillonite clay mineral was more affected by the initial water saturation,which was mainly caused by the fact that montmorillonite was a bentonite and its strong water absorption capacity led to fewer sites available for methane adsorption on the clay mineral surface.The methane adsorption capacity for the samples of two clay mineral decreased with the increase of temperature.With the increase of pore pressure,methane adsorption capacity for the samples of both clay mineral increased,indicating that the increase of pore pressure would promote adsorption.The adsorption capacity for the samples of both clay mineral increased with the decrease of particle size,which was caused by the fact that the small pores inside the clay mineral particles were exposed to a greater extent,increasing the internal surface area of the samples and providing more adsorption sites.This paper also found that no matter what kind of factors discussed in this paper,the methane adsorption capacity for the samples of montmorillonite clay mineral higher than the samples of kaolin clay mineral,this is due to the higher microscopic porosity development for the samples of montmorillonite clay mineral,it also proves that there is a great correlation between the methane adsorption capacity of clay mineral and the development degree of pores,and the development degree of micro-pores plays a crucial role in the adsorption capacity.The higher the development degree of micro-pores,the stronger the adsorption capacity will be. |
PDF Full Text Request