scholarly journals Effect of Aromatic Concentration of a Fischer-Tropsch Fuel on Thermal Stability

2012 ◽  
Author(s):  
Jennifer Lindsey Suder Klettlinger
Keyword(s):  
Thermal Stability ◽  
Thermal Oxidation ◽  
Break Point ◽  
Jet Fuel ◽  
Fuel Composition ◽  
Fischer Tropsch ◽  
Commercial Grade ◽  
Testing Method ◽  
Aromatic Content ◽  
Thermal Stability Of

Fischer-Tropsch (F-T) jet fuel composition differs from petroleum-based, conventional commercial jet fuel because of differences in feedstock and production methodology. Fischer-Tropsch fuel typically has a lower aromatic and sulfur content and consists primarily of iso and normal parafins. The ASTM D3241 specification for Jet Fuel Thermal Oxidation Test (JFTOT) break point testing method was used to test the breakpoint of a baseline commercial grade F-T jet fuel, and various blends of this F-T fuel with an aromatic solution. The goal of this research is to determine the effect of aromatic content on the thermal stability of Fischer-Tropsch fuel. The testing completed in this report was supported by the NASA Fundamental Aeronautics Subsonics Fixed Wing Project.

KARBON LİF ÜRETİMİNDE POLİAKRİLONİTRİL ELYAFLARIN TERMAL OKSİDASYONU

2021 ◽  
Vol 8 (17) ◽  
pp. 160-170
Author(s):  
Mahbubor Rahman ◽  
Tuba DEMIREL ◽  
Ismail KARACAN
Keyword(s):  
Thermal Stability ◽  
Aqueous Solution ◽  
Thermal Oxidation ◽  
Oxidation Process ◽  
Ammonium Persulfate ◽  
Oxidation Reactions ◽  
Carbon Yield ◽  
Thermal Stability Of ◽  
Pan Fibers

Thermal oxidation of polyacrylonitrile (PAN) fibers was accomplished at temperatures up to 250°C for different oxidation times. Chemical integration of PAN fibers with an aqueous solution of ammonium persulfate was performed before starting thermal oxidation. The results recommend that ammonium persulfate integration enhanced the oxidation reactions of the PAN fibers and resulting in enhanced thermal stability. Ammonium persulfate impregnation followed by the oxidation process in the air environment leads to significant deviations in the characteristics of PAN fibers. To perform structural characterization of the raw and ammonium persulfate (APS) incorporated and stabilized samples, XRD, IR-spectroscopy, TGA was executed in this study. Investigation of the XRD and infrared spectroscopy outcomes recommended quick aromatization reactions with growing oxidation periods. The TGA traces indicated a comparative enhancement in the thermal stability of the PAN fibers by the increased carbon yield with the rise of the oxidation time. The overall findings recommend that ammonium persulfate incorporation was very influential in stimulating the oxidation process.

scholarly journals Extended Duration Thermal Stability Test of Improved Thermal Stability Jet Fuels

1995 ◽  
Author(s):  
Gordon L. Dieterle ◽  
Kenneth E. Binns
Keyword(s):  
Thermal Stability ◽  
Heat Exchanger ◽  
Jet Fuel ◽  
Stability Test ◽  
Bulk Temperature ◽  
Jet Fuels ◽  
Test Results ◽  
Fuel Temperature ◽  
Extended Duration ◽  
Thermal Stability Of

A single-pass, dual heat exchanger system called the Extended Duration Thermal Stability Test (EDTST) system was developed for evaluating jet fuel thermal stability. Various JP-8 fuels and thermal stability additives have been evaluated in the system. The test results indicate that additives can substantially improve the thermal stability of conventional jet fuels. Relationships of bulk and wetted wall temperatures on coking deposits that form in heated tubes have also been evaluated. To date, tests conducted with EDTST have verified that additives can improve the thermal stability of JP-8 fuels. The goal of operating at wetted wall temperatures of 260°C (500°F) has been achieved. The goal for bulk fuel temperatures of 218°C (425°F) with no deposits has not been achieved. Additional additive candidates are to be evaluated in the EDTST system to identify additives that meet both the wetted wall and bulk fuel temperature goals of this program. However, if the bulk temperature goal cannot be totally achieved, the JP-8 fuel specification will most probably be changed to take advantage of the wetted wall temperature improvement already demonstrated by a JP-8+100 additive candidate.

scholarly journals Thermal stability of jet fuel: Second quarterly report, January--March 1989

1989 ◽  
Author(s):  
Semih Eser ◽  
J. Perison ◽  
R. M. Copenhaver ◽  
H. H. Schobert
Keyword(s):  
Thermal Stability ◽  
Jet Fuel ◽  
Thermal Stability Of

scholarly journals Thermal stability of jet fuel

1989 ◽  
Author(s):  
S. Eser ◽  
J. Perison ◽  
R. Copenhaver ◽  
H. Schobert
Keyword(s):  
Thermal Stability ◽  
Jet Fuel ◽  
Thermal Stability Of

scholarly journals The Role of Sulfur in the Thermal Stability of Jet Fuel

1999 ◽  
Author(s):  
David W. Naegeli
Keyword(s):  
Thermal Stability ◽  
Induction Period ◽  
Jet Fuel ◽  
Sulfur Compounds ◽  
Inhibition Mechanism ◽  
Organic Base ◽  
Oxidation Inhibitor ◽  
Acid Catalyzed ◽  
Thermal Stability Of

The autoxidation of Jet A, dodecane, and a dodecane-15%-cumene blend doped with sulfur compounds were studied at 433 K. Oxygen, hydro peroxide and soluble gum were monitored during the autoxidation. Dodecane, cumene, and the dodecane-15%-cumene blend autoxidized rapidly, while Jet A had an induction period followed by a relatively slow post autoxidation. The results suggest that an inhibitor formed early in the post autoxidation of Jet A. Gum formed in the autoxidation of Jet A, whereas none was detected in dodecane, cumene, or dodecane-15% cumene. However, gum was detected in dodecane and dodecane-15% cumene doped with thiols and disulfides. Alkyl thiols and disulfides reduced the rate of autoxidation of dodecane, and there was an induction period in the formation of gum. Traces of sulfur (≈4 ppm) inhibited the autoxidation of dodecane-15% cumene in a way that resembled the post autoxidation of Jet A. Adding an organic base increased the rate of post autoxidation in Jet A and prevented formation of the oxidation inhibitor. An inhibition mechanism is proposed in which phenois are formed via acid-catalyzed decomposition of benzylic hydro peroxides.

scholarly journals Thermal Stability Analysis of Gevo Jet Fuel Using Ellipsometry

2018 ◽  
Author(s):  
Leigh Nash ◽  
Jennifer Klettlinger ◽  
Subith Vasu
Keyword(s):  
Thermal Stability ◽  
Stability Analysis ◽  
Alternative Fuels ◽  
Optical Constants ◽  
Jet Fuel ◽  
Test Method ◽  
Aviation Engines ◽  
Aluminum Substrates ◽  
Thickness Measurements ◽  
Thermal Stability Of

Thermal stability is an important characteristic of alternative fuels that must be evaluated before they can be used in aviation engines. This characteristic is of great importance to the effectiveness of the fuel as a coolant and to the engine’s combustion performance. In this work, the thermal stability of Gevo fuel, an alcohol to jet fuel made from plant derived feedstock, was studied. This analysis was used to comment on the effectiveness of the current thermal stability test standard. This work was performed using a spectroscopic ellipsometer to measure the thickness of deposits left on aluminum substrates. It was observed that Gevo deposit thickness increased slowly up to 375 °C and much more rapidly after that point. Similar behavior was observed in JP-8 fuel. Comparisons were also made between color standard ratings and ellipsometric thickness measurements, and it was found that in some cases, darker colors did not indicate thicker deposits. Reference tubes were used to validate the optical models used in this work, and different optical constants were found to best model the results than what are published in the ASTM D3241 test method for thermal stability.

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