Synthesis of pyrophoric active ferrous sulfide with oxidation behavior under hypoxic conditions

Ferrous sulfide produced by rust sulfuration in crude oil tank can cause accidents such as fire and explosion when exposed to air. It is quite difficult to determine the specific location of the sulfur corrosion products in crude oil tanks as well as to acquire for laboratory testing. Thus, ferrous sulfide with high spontaneous combustion activity is a good alternative for continuing the research of sulfur corrosion products. In this study, pyrophoric active ferrous sulfide sample was synthesized in laboratory. The synthetic sample was studied by X-ray diffraction (XRD), scanning electron microscopy (SEM) combined with energy dispersive spectrometer (EDS), electron probe microanalysis (EPMA) and thermal analysis (TA), respectively. The tests indicated that the synthetic sample was amorphous flocculent agglomerate and the atomic ratio of Fe and S was 1:1 approximately, and the oxidative product was mainly Fe2O3. Non-isothermal calorimetric experiments were conducted with different heating rates. The reaction atmosphere was hypoxic with a 5:95% oxygen:nitrogen gas mix. Apparent activation energy was estimated based on iso-conversional methods. It would benefit for safety on petrochemical industries such as monitoring and early warning of fire and explosion of oil tanks caused by ferrous sulfide with the obtained parameters.