Three experiments of static state storage method, low-temperature and constant-pressure storage method and low-temperature and constant-pressure storage method were carried out to investigate which method was best in ...Three experiments of static state storage method, low-temperature and constant-pressure storage method and low-temperature and constant-pressure storage method were carried out to investigate which method was best in gas hydrate. The relationships of hydrate rate, capacity and liquid temperature versus time were derived and three results were contrasted. The experimental results show lowtemperature and constant-pressure method is better than the other two methods because it's operation period is shorter and storage capacity is larger than the other two. Low-temperature and constant-pressure method is the best method. So new method will be new research objective.展开更多
In this work,experiments and comprehensive insights into the proposed covering liquid method to intensify self-preservation effect for methane(CH_(4))storage are presented.The CH_(4)hydrate decomposition percentage wa...In this work,experiments and comprehensive insights into the proposed covering liquid method to intensify self-preservation effect for methane(CH_(4))storage are presented.The CH_(4)hydrate decomposition percentage was 17.6%with the pressure of 0.61 MPa after 12 h at 266.0 K without a covering liquid,which can be reduced to 12.4%,13.8%,13.0%,and 8.3%with the pressure of 0.26 MPa,0.33 MPa,0.51 MPa,and 0.37 MPa by covering with tetrahydrofuran(THF),cyclopentane(CP),cyclohexane,and n-tetradecane,respectively.When the temperature for CH_(4)hydrate decompositionwas 274.2 K,covering with THF,CP,cyclohexane,and n-tetradecane failed to inhibit CH_(4)hydrate decomposition.The results suggested that the covering liquid may form a new solid layer(a hydrate layer or other solidified layer)around the CH_(4)hydrate,which inhibit CH_(4)transfer below the freezing point of water.However,the new solid layer cannot resist the fast transfer of CH_(4)from decomposed CH_(4)hydrate above the freezing point of water.The same phenomenon was also observed in a sodium dodecyl sulfonate(SDS)-dry solution CH_(4)hydrate formation system.Therefore,the covering method can only intensify the self-preservation effect below the freezing point of water,but cannot generate a self-preservation effect.展开更多
Grain-displacing hydrate deposits exist at many marine sites,which constitute an important part of methane hydrate resources worldwide.Attributed to the difficulties in acquiring field data and synthesizing experiment...Grain-displacing hydrate deposits exist at many marine sites,which constitute an important part of methane hydrate resources worldwide.Attributed to the difficulties in acquiring field data and synthesizing experimental samples,the formation and property characterization of grain-displacing hydrate remains less understood and characterized than the pore-filling hydrate in current literature.This study reviews the formation mechanisms of grain-displacing hydrate from the perspective of geological accumulation and microscale sedimentary property.The experimental methods of synthesizing grain-displacing hydrate in the laboratory and the current knowledge on the property of grain-displacing hydrate sediment are also introduced.Shortcomings in current theories and suggestions for future study are proposed.The work is hoped to provide valuable insights for the research into the hydrate accumulation,geophysics,and hydrate exploitation targeted at the grain-displacing hydrate in the marine sediments.展开更多
基金supported by the National Natural Science Foundation of China(No.50176051)the State Key Development Program for Basic Research of China(No.2000026306).
文摘Three experiments of static state storage method, low-temperature and constant-pressure storage method and low-temperature and constant-pressure storage method were carried out to investigate which method was best in gas hydrate. The relationships of hydrate rate, capacity and liquid temperature versus time were derived and three results were contrasted. The experimental results show lowtemperature and constant-pressure method is better than the other two methods because it's operation period is shorter and storage capacity is larger than the other two. Low-temperature and constant-pressure method is the best method. So new method will be new research objective.
基金supported by the Hunan Provincial Natural Science Foundation of China(Nos.2020JJ3030,2019JJ50567)the National Natural Science Foundation of China(Nos.21506065,21978126,and 51904330)+1 种基金the Projects of Scientific Research Fund of Hunan Provincial Education Department(No.17A199)the Scientific Research Foundation of Xiangnan University for High-Level Talents
文摘In this work,experiments and comprehensive insights into the proposed covering liquid method to intensify self-preservation effect for methane(CH_(4))storage are presented.The CH_(4)hydrate decomposition percentage was 17.6%with the pressure of 0.61 MPa after 12 h at 266.0 K without a covering liquid,which can be reduced to 12.4%,13.8%,13.0%,and 8.3%with the pressure of 0.26 MPa,0.33 MPa,0.51 MPa,and 0.37 MPa by covering with tetrahydrofuran(THF),cyclopentane(CP),cyclohexane,and n-tetradecane,respectively.When the temperature for CH_(4)hydrate decompositionwas 274.2 K,covering with THF,CP,cyclohexane,and n-tetradecane failed to inhibit CH_(4)hydrate decomposition.The results suggested that the covering liquid may form a new solid layer(a hydrate layer or other solidified layer)around the CH_(4)hydrate,which inhibit CH_(4)transfer below the freezing point of water.However,the new solid layer cannot resist the fast transfer of CH_(4)from decomposed CH_(4)hydrate above the freezing point of water.The same phenomenon was also observed in a sodium dodecyl sulfonate(SDS)-dry solution CH_(4)hydrate formation system.Therefore,the covering method can only intensify the self-preservation effect below the freezing point of water,but cannot generate a self-preservation effect.
基金supported by the National Natural Science Foundation of China(42006181,42176212,41976205,41876051)the Youth Foundation of Natural Science Foundation of Shandong Province(ZR2020QE109)+1 种基金the National Key Research and Development Project(2018YFE0126400)the Marine S&T Fund of Shandong Province for Pilot National Laboratory for Marine Science and Technology(Qingdao)(2021QNLM020002).
文摘Grain-displacing hydrate deposits exist at many marine sites,which constitute an important part of methane hydrate resources worldwide.Attributed to the difficulties in acquiring field data and synthesizing experimental samples,the formation and property characterization of grain-displacing hydrate remains less understood and characterized than the pore-filling hydrate in current literature.This study reviews the formation mechanisms of grain-displacing hydrate from the perspective of geological accumulation and microscale sedimentary property.The experimental methods of synthesizing grain-displacing hydrate in the laboratory and the current knowledge on the property of grain-displacing hydrate sediment are also introduced.Shortcomings in current theories and suggestions for future study are proposed.The work is hoped to provide valuable insights for the research into the hydrate accumulation,geophysics,and hydrate exploitation targeted at the grain-displacing hydrate in the marine sediments.
