Study On Self-ignition Reaction Characteristics And Apparent Kinetics Of Active Iron Sulfide

Self-ignition of iron sulfide is one of important reasons that cause fire and explosion in gas equipment and storage tanks.In recent years,with the increase of sulfur in crude oil,the chemical and safety personnel pay more attention to the relevant combustion of explosion accidents and prevention technology.To research safety of petroleum and petrochemical process,the project aims for studying on the self-ignition reaction characteristics and apparent kinetics of active iron sulfide with active ferrous sulfide as the representative.The major experiment and results are as follows.1?With ammonium ferrous sulfate and sodium sulfide,samples are prepared by liquid synthesis.With iron oxide and hydrogen sulfide,samples are prepared by gas-solid synthesis.Liquid sample is spontaneous at 20?,gas-solid sample reacts at 80? and the purchased is spontaneous at 400?.Liquid sample are similar to iron sulfide in storage tanks,and it's adopt2?Samples are characterized by XRD,EMPA,optical microscopy,SEM/EDX and TEM.Result of SEM/EDX is that liquid synthesis is iron sulfide(Fe1-xS)and the mainly composition is FeS and x is about zero.The molar ratio of iron and sulfur is 0.9998 by EMPA.Result of XRD is that the diffraction peak is not obvious and it's amorphous.The result of TEM is that the sample grows in a branched extension and the minimum structure is about ten nanometers.3.According to temperature programme,spontaneous combustion of sample in the air and the effects of heating rate,oxygen concentration and air flow are studied.The result shows that firstly sample adsorbs,then produces S and at last it produces SO2.The order of effect is heating rate,then oxygen concentration and then air flow.According to isothermal,sample can produce S at 80? and increase the weight in the air,and it can produce SO2 at 50?and reduce the weight under oxygen atmosphere.4.By FWO,mechanism function of the sample is G(?)=[-ln(1-?)]4 under oxygen atmosphere,while in the air mechanism function of the sample is G(a)=[-ln(1-?)]1.5 at low temperature.At high temperature,AKTS is used to calculate activation energy.The result is that activation energy of differential and integral method is about 100 to 150 kJ per mol,and activation energy by ASTME698 is 90 to 100 kJ per mol.The higher the oxygen concentration is,the lower the activation energy by ASTME698 is.