Gasoline Deposit Mechanism on Aluminum at Various Temperatures

Deposits formed due to spraying gasoline on heated aluminum tubes at 275°F (135°C) and 425°F (218°C) have been investigated for three different fuels-a catalytic-cracked naphtha, a high-deposit fuel, and indolene clear (a low depositing reference fuel). The high-deposit fuel, used extensively in Coordinating Research Council (CRC) research programs, was also used in developing the bench test conditions used to generate deposits in this work. Silica gel and clay treatment of the test fuels were performed to isolate potential deposit precursors prior to bench testing, to evaluate the magnitude of deposits formed, and to provide samples for chemical analysis. Through the use of ESCA, FTIR, GPC, and GC/MS techniques, the nature of deposits at different temperatures have been characterized, and the potential mechanisms discussed.