The corrosion degree of LPG copper sheet is influenced by whether the oil refining: removing acidic compounds is an important purpose of oil refining, and the corrosion of copper sheet is the control index of the degree of acidic compound removal. Acidic compounds in liquefied gas basically have two types of acidic oxides and active sulfides. Active sulfides include elemental sulfur, hydrogen sulfide and mercaptan, thiophenol (collectively referred to as thiol sulfur). Acid oxides and hydrogen sulfide are more acidic and both are easily removed from the oil by alkaline washing. In contrast, mercaptan sulfur is less acidic, and relying on alkali washing alone to remove mercaptans requires a large amount of lye, generating a large amount of malodorous alkali residue, which is generally converted to disulfide through a catalytic oxidation process. Elemental sulfur at room temperature neither reacts with alkali nor with acid, and is difficult to get rid of from the oil, so most of the causes of copper corrosion of oil are caused by elemental sulfur. Elemental sulfur alone, only 0.34ppm can cause obvious gray-black corrosion.
Elemental sulfur sources have two aspects, one is the crude oil itself with, this situation is generally rare; the second is the hydrogen sulfide in the desulfurization of alcohol process this weak oxidation environment, which is the formation of elemental sulfur corrosion is the main cause.
To sum up, the influence factors of LPG copper corrosion tester in the oil refinement is not mainly manifested in the desulfurization alcohol failure and desulfurization alcohol process to form elemental sulfur two aspects. Therefore, improve the effect of desulfurization alcohol, inhibit the formation of desulfurization alcohol process elemental sulfur is the fundamental measure to solve the copper corrosion test failed.
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