Influences of Sodium sulfate on High Temperature Corrosion and

• Main Authors: Pan, Jenq-Yih, 潘正益
• Other Authors: Lin Cherng-Yuan
• Format: Others
• Language: zh-TW
• Published: 1996
• Online Access: http://ndltd.ncl.edu.tw/handle/07752314893126008470

碩士 === 國立海洋大學 === 航運技術研究所 === 84 === Diesel fuel oil A which approximates ASTM No. 2 D oil and its emulsion of water-in-oil type were used as the test oils to investigate the influences of the contents of sodium sulfate in oils and sodium chloride in atmospheric air on the combustion and emission characteristics as well as corrosion phenomena of carbon steels. An emulsifying and homogenizing machine was employed to stir the Na2SO4 powder and the oil to constitute a homogeneous oil mixture.The oil mixture was thereafter injected by a oil pump o a small-sized industrial burner, atomized with inlet air, and burned within a furnace made of stainless steel in turn. In the case of the consideration of salty atmospheric air effect, the inlet air adjusted to a 3.0 ppm concentration of NaCl was ultrasonically vibrated into a fine mist spray before entering the burner. The results show that the existence of sodium sulfate in the oils would incur a less extent of chemical reaction, leading to decreased heat release and a lower attainable gas temperature. Larger formation of sulfur dioxide was also observed in the burning gas. The metallic material was therefore more susceptible to the attack of higher concentration of sulfuric acid.In addirion,a complex salt composed of sulfate and chlorine component would swiftly react with the oxidation layer to produce a compound with low melting point on the surface of the materials. The occurring temperature for the serious corrosion is therefore decreased. It was also found in this study that the burning of the emulsified oil with water resulted in the improvement of thermal efficiency, leading to the reduction of the smoke and nitrogen oxides formation. However,large release of oxygen gas and water vapor from burning the emulsions of water-in-oil significantly promoted the oxidation process of the materials.Distructive pitting hole failures and deteriorating corrosion phenomena occurring in grain boundaries which seriously dismantled the protection of the surface layer were thereafter resulted in the accelerated corrosion of the metallic materials.