Study Of Sulfur Medium Effect On The Corrosion Of Crude Oil Tank Under5℃Temperature

the sulfur content of crude oil in the petrochemical companies was increased, the crude oil storage tanks were subjected to severe corrosion, not only shorten the life of the tanks, but also caused huge economic damage, energy resources waste and pollution. Crude oil storage tanks corrosion is increasingly concerned by enterprises, based on simple, economical and practical features of anti-corrosion coatings, for an enterprise in which the crude oil tanks were under low temperature, sulfur corrosion environment, the corrosion failure mechanism of the crude oil tanks was studied. The two kinds of undercoats and four kinds of topcoats were selected (labeled as undercoat D1, D2and topcoat M1, M2, M3, M4). Coating systems were combination of undercoat Dl and four kinds of topcoats, labeled as system A, B, C, D. Based on experiment and performance evaluation method, the anti-corrosion coatings were stuied and better preservative effect coatings were given. Research and main conclusion are as follows:(1) The hardness, adhesion, impact resistance and flexibility of anti-corrosion coatings were tested. The results showed that:the mechanical properties of undercoat D2was better than undercoat D1, four kinds of the topcoats had good mechanical properties, but the topcoats M4was not applied to the metal anti-corrosion with high speed impacted action.(2) For sulfur medium corrosive environment, corrosive medium was 3.5%Na2S solution, the EIS test of various coatings was taken. The resistance to sulfur corrosion of undercoat D2was better than undercoat D1. The topcoat M4was the best resistance to sulfur corrosion, the topcoat M1was poor resistance to sulfur corrosion. The order of sulfur corrosion resistance of coating systems were:D>B>A.(3) The immersion experiment of tank coatings was studied under low temperature environment, including analyzed the changes of quality, surface morphology and surface quality fraction of samples before and after corrosion. The corrosion mechanism and protective effect of the tank corrosion coatings were studied. The results showed that:under low temperature conditions, the temperature had little effect on the corrosion resistance of coatings; Surface of coating systems B、C、D were uniform, surface of coating system A was not uniform; Surface porosity of coatings were become large, the cossosion speed was increased after corrosion, and corrosion reaction was occurred at the coating surface defects firstly; The protection performance of coating system A was worse, the protection performance of coating system D was better, these results will provide a reference for the large application of anti-corrosion technology of crude oil storage tanks in the enterprise.