Simulation Research On Insulating Gas Adsorption And Catalytic Performance Of Porous Materials With Zeolite Structure

SF₆is widely used in insulation field due to its excellent arc extinguishing and insulation performance.However,partial discharge and other faults may occur in gas insulation equipment that works for a long time,resulting in the decomposition of SF₆to produce characteristic gases such as SO₂F₂,SOF₂,SO₂,H₂S and HF,which further leads to the deterioration of insulation performance.The on-line monitoring of SF₆gas insulation equipment can be realized by using the gas sensitive response of zeolite porous material to SF₆gas decomposition.At the same time,the selective adsorption and membrane separation of SF₆decomposition gas by zeolite material can be used to achieve the purification of SF₆insulating gas.The all-silicon MER zeolite was selected and doped with Pd,Au and Pt metal atoms to improve the gas-sensitive response ability.Based on first principles,the gas-sensitive characteristics of three modified MER zeolite to SF₆decomposition products HF,H₂S,SO₂,SOF₂and SO₂F₂were simulated.The parameters of charge transfer,adsorption energy,state density and molecular orbital were calculated.Based on the calculation data of the above parameters,the prospect of modified MER zeolite as a gas sensitive material to test SF₆decomposition gas was evaluated.Al-MER with a Si/Al ratio of 3.8was selected,and the charge balance was carried out by K⁺,Na⁺,Ca²⁺and Mg²⁺.Four kinds of MER zeolite structures were obtained,namely,K-Al-MER,Na-Al-MER,Ca-Al-MER and Mg-Al-MER.Combined with Monte Carlo and molecular dynamics method,the adsorption selectivity of SF₆and SF₆decomposition gas in the mixture of gas insulation equipment was calculated under the conditions of temperature 358K and pressure0-1000kpa under the normal working state of gas insulation equipment.Modified MER zeolite as an adsorbent for selective adsorption of SF₆decomposition gas to achieve the purification of SF6 insulating gas.Then,Ca-Al-MER and K-Al-MER with good adsorption selectivity obtained above were used to separate the mixed gas with a single zeolite membrane.The amorphous cell of mixed gas was constructed,and the self-diffusion coefficient,root mean square displacement and radial distribution function of cations of SF₆and its decomposition components in zeolite were calculated as evidence of molecular diffusion.Finally,the separation effect of mixed gas SF₆and its decomposition product gas at different proportions of 80%,85%,90%and 95%MER zeolite as a molecular sieve in the dynamic simulation process was explored.