Prediction of Gasoline Storage Stability

A test procedure and correlations were developed for predicting the amounts of gum and lead precipitate that will form in a gasoline during storage for periods up to 32 weeks at 110 F. The amounts of gum and lead precipitate formed in 24 commercial and military gasolines during a 16-hr oven test at 200 F were compared with the amounts formed in the same gasolines stored at 110 F and analyzed following 8-, 16-, and 32-week storage periods. A direct relationship was found between the amounts of lead precipitate formed during the oven test and those formed during long-term storage. The gum relationship, however, needed adjusting in proportion to the amount of oxygen consumed in the gum-forming reaction. The storage performance of gasoline at temperatures below 110 F for periods as long as 5 years can be estimated with a modified Arrhenius equation which is presented.