Corrosion characteristics of furnaces burning with emulsified diesel oil containing sodium sulphate

THE EFFECTS of sodium sulphate in a water-dispersed-in-oil (W/O) emulsion on the corrosion characteristics of carbon steel were experimentally investigated in this study. ASTM 2D diesel oil was used as the tested oil with SB450 carbon steel as the specimen material. An emulsifying and homogenizing machine was employed to stir sodium sulphate powder, distilled water, the diesel oil, and Span 80 surfactant to form a homogeneous mixture of emulsion. The surfactant in an emulsion plays the role of promoting the integrating force and extent of intimacy between the components of distilled water and the oil. The emulsion mixture was injected using a small-sized automatic burner, atomized by inlet air, and burned within the industrial burner. The burning gas thermally attacked the metal sheets, which were hung vertically at various axial locations. The results show that the burning of the W/O emulsion would produce great amounts of oxygen gas and water vapour, leading to significant promotion of the oxidation process of the specimen. Destructive pitting-hole failures and deteriorating corrosion phenomena occurred at the grain boundaries, which would seriously dismantle the protective oxidation film, An accelerating corrosion of the metallic material therefore appeared, In addition, the reaction of sodium sulphate with the sulphur or vanadium component in the diesel oil might form eutectic compounds with low melting points. Hence, the content of sodium sulphate would further promote the corrosion phenomena of the metallic specimen.