Study of the influence of crude oil on the spontaneous combustion risk of sulfurized rust in crude oil tanks

Spontaneous combustion risk of sulfurized rust is the main cause of fire and explosion accidents during crude oil storage and transportation. In order to analyze the effect of crude oil on the thermal behavior of sulfurized rust, thermos-gravimetric analysis (TG) and differential scanning calorimeter (DSC) were used to evaluate the thermal behavior of the sulfurized rust, crude oil and their mixture. A deconvolution method is employed to analyze the complex thermal behavior of the mixture. The results indicate that the oxidation of crude oil can be separated into low temperature oxidation (LTO) and high temperature oxidation (HTO). The thermal behavior of mixture is similar to that of crude oil. It can be found that sulfurized rust may inhibit the decarboxylation reaction of crude oil in LTO while the sulfurized rust and crude oil promote each other in the HTO. With the increases of the mass percentage of crude oil, the onset temperature of mixture decreases and the reaction heat increases. The promotion effect is the most significant when the ratio of sulfurized rust and crude oil is 1:1.