Study On SOF₂ Concentration Detection Technology In GIS

Gas insulated switchgear（GIS）is widely used in power system because of its excellent insulation performance,good shock resistance and fire protection performance,small floor area,easy installation,low equipment failure rate,long maintenance period,high reliability and so on.Once GIS breaks down,it will seriously threaten the security of power system.Therefore,it is necessary to establish the early insulation evaluation and early warning mechanism of GIS equipment to minimize the probability of GIS failure.SOF₂is an important characteristic gas with faults in GIS,and the current detection technology has great defects.In this paper,a new technology is proposed to hydrolyze SOF₂to SO₂,and indirectly detect the concentration of SOF₂by detecting the change of SO₂concentration before and after hydrolysis.In this paper,the kinetics of SOF₂hydrolysis and the catalytic performance of hierarchical Pt/ZSM-5 for SOF₂hydrolysis were studied.At last,the portable detection scheme of SOF₂was given.The results show that:（1）when the content of H₂O is much higher than that of SOF₂,the hydrolysis of SOF₂is a first-order reaction.Temperature has a significant effect on the hydrolysis rate constant of SOF₂.High temperature is beneficial to the hydrolysis of SOF₂.（2）The support of hierarchical ZSM-5 zeolites was prepared by steam assisted conversion method.The molecular sieves were impregnated with metal Pt by equal volume impregnation method.Successful preparation of hierarchical Pt/ZSM-5 catalyst with microporous and mesoporous multi-stage pore.The average pore diameter of the catalyst was 4.41nm,and the average pore diameter of the mesopores was 10.55nm.（3）The catalyst of hierarchical Pt/ZSM-5 has good catalytic performance in the hydrolysis of SOF₂.After adding the catalyst,the hydrolysis rate constant of SOF₂increases and the activation energy decreases significantly.（4）Pt loading,temperature and catalyst usage are important factors in the hydrolysis of SOF₂catalyzed by hierarchical Pt/ZSM-5.The rate constant of hydrolysis increased first and then decreased with the increase of Pt loading,increased with the increase of temperature,and increased first and then stabilized with the increase of catalyst usage.（5）The order of influence degree of each factor on the rate constant of hydrolysis reaction is:temperature>Pt loading>hierarchical Pt/ZSM-5usage.（6）When Pt loading is 2.29%,temperature is 393K and catalyst hierarchical Pt/ZSM-5 is 0.53g,the maximum hydrolysis rate constant is 10.49×10^-4s^-1.（7）Under the catalysis of hierarchical Pt/ZSM-5,the hydrolysis of SOF₂is complete.The on-site determination of SOF₂can be realized by measuring the difference of SO₂concentration before and after hydrolysis.