Study On The Colour Stability Of Fluidized Catalytic Cracking Gasoline

The paper reviewed the present international and domestic study progress of the stability of gasoline. A research has been carried out systematicly on the color changing from normal color to pink for the FCC gasoline produced from the feedstock with high level of S, N & O. A new idea is proposed to the formation of pink substance and the chemical channel to the change of color. Though there is no national standard on the color of gasoline, colourless or faint yellow is usually acceptable for gasoline. With regarding to the current existing problem of pink gasoline, there is neither theoretic analysis nor solutions. So the research is of strong exploration.The properties of the pink gasoline from one refinery and reactivity of the pink substance were studied extensively, which provided foundations for making a correct analysis and developing a feasible solution. The reactions between pink gasoline and alkalis, inorganic and organic acids, oxygenants and reductants, polymerization initiators and polymerization inhibitors were explorated. It was also discovered that the pink gasoline can change to faint yellow when induced by sunlight or UV light. The simulation experiments with phenol, aniline and para-benzoquinone were carried out, and some new experimental phenomenology was discovered. It was concluded that the red substance is basic and recursive, in addition, photochemical reaction can also occur.The reason for the color changing of gasoline to pink was analysized. The related investigation was carried out to the pink substance, which was separated through the chromatographic column method. The red substance was concentrated and separated by a chemical extraction method. Instrumental analysis included Elementary analysis, GC analysis and GC-MS analysis ware used to determine the content of basic nitrogen, phenol and mercaptan of gasoline. It was confirmed that the red substance is a complex compound formed between the quinine and arylamine, together with phenol. The transform channel of the red substance was analysised from the view point of photochemistry, and then the cause of the formation and color conversion of the pink substance was theoretically introducedTechnical programs were proposed to decolor the pink gasoline. The technical programs include the homogeneous reaction dispersion technology, pink substance in the gasoline reacted with chemical additive to righten the color of gasoline; the technical process named adsorption bleaching with fixed bed, with higher adsorption capacity and longer operation cycle; the photochemical decoloration program with UV photo-induced method, a green chemistry original method; and the liquid -liquid extraction decoloring technology, a small quantity of inorganic reaction liquid was added into the pink gasline, making the pink substance reacts with reaction liquid to restore the color of the pink gasoline. The technical process named adsorption bleaching with fixed bed and the homogeneous reaction dispersion technology were advised as industrial reference scheme.