Preparation Of Metal Nano-Composite Materials And Application In Methane Hydrate

Natural gas hydrate is a compound resembling ice,which is formed by water molecules and natural gas molecules under suitable condition.And the theoretical gas capacity of hydrate can reach 180 v/v?methane/hydrate?.Compared with the compressed natural gas and liquefied natural gas,hydrate can reduce the cost of storage and transportation and increase the safety performance effectively due to the mild condition of preparation and storage.Although the preparation condition is mild relatively?3MPa,275.15K?,the slow formation rate and poor density of hydrate limit its industrial production and application greatly.In order to solve the above problems,the SDS@Fe₃O_<sub>4 sol and SDS@PS@Ag composite nanospheres were prepared to promote methane hydrate formation,specific research contents are as follows:SDS@Fe₃O_<sub>4 sol with uniform particle size distribution was prepared by dispersing nano-Fe₃O_<sub>4 powder into sodium dodecyl sulfate?SDS?solutions through ultrasonic dispersing apparatus,The SDS@Fe₃O_<sub>4 nanoparticles can be stable in liquid phase,and they were used in methane hydrate experiment to study its effect on hydrate formation.The results showed that compared with SDS,the sol of SDS@Fe₃O_<sub>4 can effectively shorten the induction time of methane hydrate formation.Compared with SDS,SDS@Fe₃O_<sub>4 also can improve the storage ratio of gas hydrate at low concentration,for example,when the concentration was 1mmol/L?based on the concentration of SDS?,the storage ratio can increase about 20%,and it also can increase about 10% when the concentration was 2mmol/L.In addition,SDS@Fe₃O_<sub>4 produced excellent recycling performance during the five cycles of hydrate formation-dissociation.Polystyrene/acrylic acid copolymer microspheres with SDS fixed on the surface were prepared by emulsion polymerization?SDS@PS-COOH?,and then silver nanoparticles were coated in nanospheres by in situ reduction to prepared SDS@PS@Ag nanospheres.The silver particles arranged on nanospheres uniformly,composite nanospheres can exist stably in liquid phase.The experimental results show that SDS@PS@Ag nanoparticles can not only induce methane hydrate reaction at low concentrations?0.05,0.1,0.2mmol/L?,and the formed hydrate is more compact.When using SDS@PS@Ag which the silver coating rate is 50%,the time of hydrate complete reaction is shorten about 4 hours compared with the SDS@PS-COOH,which is not covered by the silver particles.