Mechanism of deposit formation on fuel-wetted metal surfaces
- Southwest Research Institute, San Antonio, TX (United States)
Experiments were performed in a Single-Tube Heat Exchanger (STHE) apparatus and a Hot Liquid Process Simulator (HLPS) configured and operated to meet Jet Fuel Thermal Oxidation Tester (JFTOT) ASTM D 3241 requirements. The HLPS-JFTOT heater tubes used were 1018 mild steel, 316 stainless steel (SS), 304 stainless steel (SS), and 304 SS tubes coated with aluminum, magnesium, gold, and copper. A low-sulfur Jet A fuel with a breakpoint temperature of 254{degrees}C was used to create deposits on the heater tubes at temperatures of 300{degrees}C, 340{degrees}C, and 380{degrees}C. Deposit thickness was measured by dielectric breakdown voltage and Auger ion milling. Pronounced differences between the deposit thickness measuring techniques suggested that both the Auger milling rate and the dielectric strength of the deposit may be affected by deposit morphology/composition (such as metal ions that may have become included in the bulk of the deposit). Carbon burnoff data were obtained as a means of judging the validity of DMD-derived deposit evaluations. ESCA data suggest that the thinnest deposit was on the magnesium-coated test tube. The Scanning Electron Microscope (SEM) photographs showed marked variations in the deposit morphology and the results suggested that surface composition has a significant effect on the mechanism of deposition. The most dramatic effect observed was that the bulk of deposits moved to tube locations of lower temperature as the maximum temperature of the tube was increased from 300{degrees} to 380{degrees}C, also verified in a single-tube heat exchanger. The results indicate that the deposition rate and quantity at elevated temperatures is not completely temperature dependent, but is limited by the concentration of dissolved oxygen and/or reactive components in the fuel over a temperature range.
- Research Organization:
- USDOE Assistant Secretary for Fossil Energy, Washington, DC (United States). Office of Technical Management
- OSTI ID:
- 45059
- Report Number(s):
- CONF-941022-Vol.1; ON: DE95008873; CNN: Contract DAAK70-87-C-0043; Contract DAAK70-92-C-0059; TRN: 95:003336-0015
- Resource Relation:
- Conference: 5. international conference on stability and handling of liquid fuels, Rotterdam (Netherlands), 3-7 Oct 1994; Other Information: PBD: 1995; Related Information: Is Part Of Proceedings of the 5th international conference on stability and handling of liquid fuels. Volume 1; Giles, H.N. [ed.]; PB: 431 p.
- Country of Publication:
- United States
- Language:
- English
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