Effects of Chemical Components on Stability of FCC Gasoline

The effects of the mercaptan sulfur, nitrogen compounds, phenolic compounds, and conjugated dienes on the stability of FCC naphtha were investigated by means of chemical treatment and addition of model compounds. Experimental results indicated that conjugated dienes in spite of its very small content in naphtha played the most important effect on the stability of naphtha. After the conjugated dienes have been removed, the stability would increase significantly. A high amount of mono-olefins is another important reason for naphtha oxidation although its effect is less than that of dienes. A certain amount of phenolic compounds should be retained during the naphtha refining. Nitrogen compounds and sulfur compounds cause poor effects on the stability of naphtha, but their effects are minimal because of the small quantity in the naphtha.