The relationship between sulfides’ corrosion of equipment and temperature t

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 When t≦120℃, the sulfides remain undecomposed; in an anhydrous environment, they cause no corrosion to the equipment； However, when it contains water, various H2S-H2O types of corrosion occur in the light oil section.  120℃﹤t≦240℃: The active sulfides in crude oil remain undecomposed, so there is no corrosion to the equipment.  At 240℃ < t ≤ 340℃, sulfides begin to decompose, producing H2S which initiates corrosion of the equipment; this corrosion intensifies as the temperature rises.  At 340℃﹤t≦400℃, H2S begins to decompose into H2 and S; the corrosion reaction equations are: H2S→H2+S, Fe+S→FeS, R-S-H (thiol) + Fe→FeS+unsaturated hydrocarbons.  At 420℃﹤t≦430℃, high-temperature sulfur causes the fastest corrosion of equipment ；  When t>480℃, the sulfides are nearly completely decomposed, and the corrosion rate decreases ；  When t>500℃, it is not within the range of sulfide corrosion; rather, it is high-temperature oxidative corrosion.  In the presence of water, hydrogen sulfide can cause two types of corrosion in carbon steel equipment: uniform corrosion and pitting corrosion ； Wet hydrogen sulfide stress corrosion cracking.