Gas Hydrates Equilibrium Mechanism And Separation Technology

The gas hydrate's equilibrium is the base for its technology extensive use. In the field of natural gas hydrate as a way of gas storage and transportation technology field, SDS is normally added to promote gas hydrate production in industry and laboratory.However,SDS's influence on thermodynamic equilibrium is still not studied thoroughly. The thesis starts with the judgement of gas hydrate formation conditions by experimental methods, analyzes SDS's thermodynamic effect by experiment and theory, which establishes the foundation for the further study of gas hydrate.The thesis develops judgement method, finishes CH₄/CO₂ hydrate equilibrium experiments, studies SDS thermodynamic accelerating mechanism, amends CH₄/CO₂ hydrate theoretical mode by SDS existence and accomplishes CH₄+CO₂ gas mixture separation by hydrate. First of all, search gas hydrate equilibrium judgement by practice.After completing most methods in the document,finally find a set of pure gas hydrate equilibrium judgement methods;compared with others ,it has many advantages: simple equipment, short period and high reliability,etc.Secondly, study the mechanism of SDS's influence on gas hydrate thermodynamic, and find out that when SDS is beyond CMC,its thermodynamic accelerative effect is predominant,by the reason that superfluous SDS form micelle inside of solution causing"solubilizing"effect.In order to analyze its detailed influence, design CH₄/CO₂ hydrate equilibrium experiments under different SDS consistencies (all above CMC),and discover that CO₂ hydrate equilibrium pressure decreases≤10-1, CH₄ decreases≤10-3.From this, SDS has a certainly extensive effect on gas hydrate thermodynamic equilibrium,related to different gas species; as SDS consistency increases,equilibrium pressure drops in smaller and smaller extent.Thirdly,by using experimental data, utilize Chen-guo mode and P-T equation to calculate SDS solution activity in CH₄/CO₂ hydrate system, furthermore, substitute caculated data to get equilibrium pressure and compare with experimental and Csmhyd results. In CH₄ hydrate system, as SDS consistency increases, activity coefficient departs from 1 further and micelle consistency effects deeply on activity10-3; the thesis's deviation decreases, and prediction is more precise. In CO₂ hydrate system, as SDS consistency increases, activity departs from 1 further10-2,better than CH4,which depends on CO₂'s influence on activity; the thesis's deviation decreases, and prediction is more precise.Lastly,above on former analysis of experiment and theory, finish primary search of CH₄+CO₂ gas mixture separation technology ,then find out optimal separation region in phase graphy,and verify its feasibility.