Study On The Oxidation Of Sulfide Under The Fiber-film Desulfurizaion Process Condition

The fiber-film contactor technology was widely used in the desulfurization process of light oil due to its high transfer efficiency, excellent separating effect, etc. In view of the problems existing in the fiber-film desulfurization process, the catalytic oxidation of sulfides, the quantitative analyses of sulfides, and the distribution of oxidation products were studied.The quantitative analyses of sulfides in cobalt phthalocyanine tetrasulfonate alkaline solution under fiber-film desulfurization process condition was established.The barium chromate spectrophotometry which was used to determine the content of SO4^2- in catalyst alkaline solution was affected by the concentration of OH^-,S^2-,S₂O₃^2- and catalyst. The iodine amount method was used to determine the content of S₂O₃^2-,but the content of OH^-,S^2- and catalyst could affect the results. The contents of S^2-,C₃H₇S^- in catalyst alkaline solution could be simultaneously determined by potentiometric titration. It makes the analysis simple and accurate. The element sulfur was detected by copper corrosion test.Under the fiber-film desulfurization process condition, the catalytic oxidation of sulfides and the distribution of oxidation products were investigated. For the oxidation performance of sodium sulfide in catalyst alkaline solution, the oxidation of S^2- at different conditions was investigated. The results indicated that the main products were S₂O₃^2- and element sulfur. The conversion of sulfide and the yield of thiosulfate increased along with the increase of temperature, recation time, the content of oxygen, and the concentration of catalyst. However, for the oxidation of sodium mercaptide in catalyst alkaline solution, the oxidation product was disulfide. The results showed that the longer reaction time was in favor of the produce of disulfide, but the sulfide in the solution was unfavorable for the oxidation of sodium mercaptide.For the gasoline containing hydrogen sulfide and mercaptan, the distribution of sulfur compound products during the continuous extraction and oxidation was studied. With the increase of circular times of catalyst alkaline solution in the extraction and oxidation process, the conversions of S^2- and RS- were decreased, while the content of element sulfur and thiosulfate were increased. The element sulfur could dissolve into gasoline, which led to copper strip corrision for gasoline. Therefore, how to avoid the formation of element sulfur was studied, and the deep oxidation condition of sulfide was ditermined.