Elementary Study On Phase Equilibrim Of Gas Hydrate For Lake Salt Exploitation And Biogas Purity

The technology of gas hydrate used for the storage of energy,natural gas transportation,carbon dioxide storage deposited in seabed,gas separation,sea water desalization and other industry fields,which is a new technology that has broadly applications foreground.This passage brings the new idea of salt exploration and bioenergy purification by gas hydrate technology.It simulated the phase equilibrium condition of gas hydrate in sodium chloride saturated solution and ternary mixture gas (CH₄+CO₂+H₂S) hydrate in pure water.It researched the phase equilibrium condition of hydrate of HCFC141b in sodium chloride saturated solution by experiment.It analyzed feasibility of the new idea of salt exploration and bioenergy purification by gas hydrate technology.First of all,this assignment calculated phase equilibrium condition of CH₄,C₂H₆,C₃H₈ and HCFC141b hydrate in sodium chloride saturated solution internationally, which based on van der Waals-Platteeuw Model,combined Three-Parameter Equation presented by Du Ya and Guo Tianmin which calculate Langmuir constant and Equation of Pitzer which calculate water activity in electrolyte solution and PR state equation and SRK state equation.It also predicted phase equilibrium condition of ternary mixture gas hydrate(CH₄+CO₂+H₂S) in pure water.Moreover,it researched phase equilibrium condition of HCFC141b hydrate experimently on high pressure hydration reaction test-bed which is entirely clarity.It contrasted with predict result theoretically,which shows that the max relative difference between predict result theoretically and result of experiment is 0.97%,phase equilibrium of HCFC141b hydrate Q2 is(10.069kPa,259.8K) in 26wt%sodium chloride solution.The results show that all of methane,ethane,propane and HCFC141b can form hydrate in 26wt%sodium chloride solution.From the basis of above,the freezing point of sodium chloride solution is 250.81K when the concentration of the solution is 26%,the freezing point decrease as the increase of pressure,moreover the formation temperature of hydrate is higher than this freezing point and also higher than the average environment temperature (0℃-10℃) in the coldest month at Qinghai area at standed condition.So it is feasible that energy conservation by the hydrate technology through environment temperature,which exploiting saline lakes in high-cold region.Through comparing with the phase equilibrium condition of hydrate of three gas(methane,ethane and propane) in sodium chloride solution,determined the suited gas for exploiting saline lakes in high-cold region by hydrate techonolgy.Propane is more suitable to the exploiting saline lakes compare with methane,ethane and propane.Obviously,it is a potential energy-saving and environment-friendly method used by environment temperature for promoting hydrate formation and exploiting saline lake.It is also a new method for exploiting saline lakes in high-cold region.The rearch of assignment provide theory support for exploiting saline lake thourgh hydrate thchology.On the other hand,the phase equilibrium data of mixture gas(CH₄+CO₂+H₂S)hydrate supply definite theory foundation for bioenergy purification by hydrate technology.