Evaluation of the Effectiveness of a Metal Deactivator and Other Additives in Reducing Insolubles in Aviation Fuels

1997 ◽  
Vol 119 (4) ◽  
pp. 830-835 ◽  
Author(s):  
E. G. Jones ◽  
W. J. Balster ◽  
L. M. Balster
Keyword(s):  
Surface Passivation ◽  
Aviation Fuel ◽  
Jet Fuels ◽  
Dissolved Metals ◽  
Radical Initiation ◽  
Tubular Heat Exchanger ◽  
Advantages And Disadvantages ◽  
Fundamental Information ◽  
Aircraft Fuel ◽  
Free Radical Initiation

Surface fouling in aircraft fuel lines resulting from autoxidation of aviation fuel leads to reduced efficiency as deposits collect on heat exchangers, nozzles, and servocontrols and may ultimately lead to system failure. Metal surfaces and trace quantities of metals dissolved in the fuel exacerbate the surface-fouling problem because they can catalyze free-radical initiation, thereby accelerating autoxidation. Additives and additive packages containing antioxidants, dispersants, and metal deactivators (MDA) have been shown to reduce insolubles in some fuels. Because of metal chelation and possible metal-surface passivation, MDA has been proposed as an additive component to be included in all fuels, even those without dissolved metals. The goal of the present study was to obtain fundamental information on the behavior of MDA under conditions where surface-passivation effects are minimal. Experiments have been conducted to (1) study the effects of adding MDA to fuels containing a significant concentration of dissolved metals (i.e., chelation) and to those containing minor concentrations of dissolved metals and (2) investigate interactions when MDA is used in conjunction with an antioxidant and a dispersant. Simple fuel-line-fouling simulations with a single-pass tubular heat exchanger operated under near-isothermal conditions have been conducted to study the thermal behavior at 185°C of several neat and MDA-treated jet fuels as well as fuels treated with MDA plus other additives. Comparison of neat and treated fuels is based on several criteria: (1) dependence of autoxidation on stress duration, (2) dependence of surface deposition on stress duration, and (3) quantity of total insolubles (bulk filterables and surface deposits). Potential advantages and disadvantages of using MDA alone and in combination are discussed.

scholarly journals Evaluation of the Effectiveness of a Metal Deactivator and Other Additives in Reducing Insolubles in Aviation Fuels

1996 ◽  
Author(s):  
E. Grant Jones ◽  
Walter J. Balster ◽  
Lori M. Balster
Keyword(s):  
Surface Passivation ◽  
Aviation Fuel ◽  
Jet Fuels ◽  
Dissolved Metals ◽  
Radical Initiation ◽  
Tubular Heat Exchanger ◽  
Advantages And Disadvantages ◽  
Fundamental Information ◽  
Aircraft Fuel ◽  
Free Radical Initiation

Surface fouling in aircraft fuel lines resulting from autoxidation of aviation fuel leads to reduced efficiency as deposits collect on heat exchangers, nozzles, and servocontrols and may ultimately lead to system failure. Metal surfaces and trace quantities of metals dissolved in the fuel exacerbate the surface-fouling problem because they can catalyze free-radical initiation, thereby accelerating autoxidation. Additives and additive packages containing antioxidants, dispersants, and metal deactivators (MDA) have been shown to reduce insolubles in some fuels. Because of metal chelation and possible metal-surface passivation, MDA has been proposed as an additive component to be included in all fuels, even those without dissolved metals. The goal of the present study was to obtain fundamental information on the behavior of MDA under conditions where surface-passivation effects are minimal. Experiments have been conducted to 1) study the effects of adding MDA to fuels containing a significant concentration of dissolved metals (i.e., chelation) and to those containing minor concentrations of dissolved metals and 2) investigate interactions when MDA is used in conjunction with an antioxidant and a dispersant. Simple fuel-line-fouling simulations with a single-pass tubular heat exchanger operated under near-isothermal conditions have been conducted to study the thermal behavior at 185°C of several neat and MDA-treated jet fuels as well as fuels treated with MDA plus other additives. Comparison of neat and treated fuels is based on several criteria: 1) dependence of autoxidation on stress duration, 2) dependence of surface deposition on stress duration, and 3) quantity of total insolubles (bulk filterables and surface deposits). Potential advantages and disadvantages of using MDA alone and in combination are discussed.

scholarly journals Surface Fouling in Aviation Fuels: An Isothermal Chemical Study

1995 ◽  
Author(s):  
E. Grant Jones ◽  
Walter J. Balster ◽  
James M. Pickard
Keyword(s):  
Experimental Test ◽  
Chemical Study ◽  
Aviation Fuel ◽  
Test Time ◽  
Tubular Heat Exchanger ◽  
Surface Deposition ◽  
Test Conditions ◽  
Aircraft Fuel ◽  
Dynamic Experiments ◽  
Selection Of

Surface fouling in aircraft fuel lines that results from autoxidation of aviation fuel remains a serious and very complicated problem. This area has been studied using two Jet-A fuels, POSF-2827 and POSF-2980. The results of a series of dynamic experiments conducted in a single-pass, tubular heat exchanger operated at very slow flow rates under near-isothermal conditions are reported herein. Such studies, by minimizing complications resulting from fluid dynamics and heat flow, constitute a simpler global approach to the chemistry of fouling. The basis for the selection of experimental test conditions is discussed, and data from measurements of dissolved oxygen and surface deposition as a function of fuel stress duration are presented. The effects of parameters such as reaction temperature, tube diameter, experimental test time, and fuel dopants are considered.

Surface Fouling in Aviation Fuels: An Isothermal Chemical Study

1996 ◽  
Vol 118 (2) ◽  
pp. 286-291 ◽  
Author(s):  
E. G. Jones ◽  
W. J. Balster ◽  
J. M. Pickard
Keyword(s):  
Experimental Test ◽  
Chemical Study ◽  
Aviation Fuel ◽  
Test Time ◽  
Tubular Heat Exchanger ◽  
Surface Deposition ◽  
Test Conditions ◽  
Aircraft Fuel ◽  
Dynamic Experiments ◽  
Selection Of

Surface fouling in aircraft fuel lines that results from autoxidation of aviation fuel remains a serious and very complicated problem. This area has been studied using two Jet-A fuels, POSF-2827 and POSF-2980. The results of a series of dynamic experiments conducted in a single-pass, tubular heat exchanger operated at very slow flow rates under near-isothermal conditions are reported herein. Such studies, by minimizing complications resulting from fluid dynamics and heat flow, constitute a simpler global approach to the chemistry of fouling. The basis for the selection of experimental test conditions is discussed, and data from measurements of dissolved oxygen and surface deposition as a function of fuel stress duration are presented. The effects of parameters such as reaction temperature, tube diameter, experimental test time, and fuel dopants are considered.

The Use of Styrenes as Embedding Media for Electron Microscopy

1971 ◽  
Vol 29 ◽  
pp. 488-489
Author(s):  
Edward D. De-Lamater ◽  
Eric Johnson ◽  
Thad Schoen ◽  
Cecil Whitaker
Keyword(s):  
Electron Microscopy ◽  
Surface Tension ◽  
Ultraviolet Light ◽  
Methyl Ethyl Ketone Peroxide ◽  
Methyl Ethyl ◽  
Styrene Polymerization ◽  
Radical Initiation ◽  
Tertiary Butyl ◽  
Low Viscosity ◽  
Free Radical Initiation

Monomeric styrenes are demonstrated as excellent embedding media for electron microscopy. Monomeric styrene has extremely low viscosity and low surface tension (less than 1) affording extremely rapid penetration into the specimen. Spurr's Medium based on ERL-4206 (J.Ultra. Research 26, 31-43, 1969) is viscous, requiring gradual infiltration with increasing concentrations. Styrenes are soluble in alcohol and acetone thus fitting well into the usual dehydration procedures. Infiltration with styrene may be done directly following complete dehydration without dilution.Monomeric styrenes are usually inhibited from polymerization by a catechol, in this case, tertiary butyl catechol. Styrene polymerization is activated by Methyl Ethyl Ketone peroxide, a liquid, and probably acts by overcoming the inhibition of the catechol, acting as a source of free radical initiation.Polymerization is carried out either by a temperature of 60°C. or under ultraviolet light with wave lengths of 3400-4000 Engstroms; polymerization stops on removal from the ultraviolet light or heat and is therefore controlled by the length of exposure.

Relative Reactivities of 1,1,1-Trichloroethane and 1,1,1-Trichlorotrifluoroethane in Competitive Addition Reactions

1992 ◽  
Vol 57 (6) ◽  
pp. 1291-1298 ◽  
Author(s):  
František Adámek ◽  
Milan Hájek ◽  
Zbyněk Janoušek
Keyword(s):  
Free Radical ◽  
Reaction Mechanism ◽  
Relative Reactivity ◽  
Addition Reactions ◽  
Radical Initiation ◽  
Amine Complexes ◽  
Free Radical Initiation ◽  
Ru Complexes ◽  
Radical Initiators

Relative reactivity of CH3CCl3 and CF3CCl3 measured in competitive addition reactions with 1-hexene in the presence of free radical initiators or Cu, Pd and Ru complexes was found to depend on the type of catalyst. The unusual course of the reaction has been found in the additions catalyzed with copper(I)-amine complexes where CH3CCl3 in competition with CF3CCl3 was completely unreactive. The results have been explained in terms of the change of reaction mechanism and compared with classical free radical initiation.

scholarly journals The Thermal Stability of Aviation Fuel

1984 ◽  
Author(s):  
J. S. Mills ◽  
F. R. Edwards
Keyword(s):  
Thermal Stability ◽  
Research Tool ◽  
Aviation Fuel ◽  
Engine Oil ◽  
Thermally Stable ◽  
Fuel System ◽  
Flow Rates ◽  
Aircraft Fuel ◽  
Oil Cooler ◽  
Thermal Stability Of

The propensity of aviation turbine fuels to produce deposits in the oil-cooler and filter sections of aircraft fuel systems has been examined using a rig that simulates the fuel system of an aircraft and which employs realistic flow rates. All the fuels examined were found to be thermally stable up to temperatures in excess of those currently attained in engine oil coolers. Comparison with results obtained with the JFTOT indicates that this is not suited for use as a research tool.

scholarly journals Development of Electromobility in Terms of Freight Transport

2019 ◽  
Vol 10 (2) ◽  
pp. 23-32 ◽  
Author(s):  
Václav Cempírek ◽  
Iwona Rybicka ◽  
Ivica Ljubaj
Keyword(s):  
Power Systems ◽  
Current System ◽  
Freight Transport ◽  
Future Research ◽  
Advantages And Disadvantages ◽  
Traction Motors ◽  
Fundamental Information ◽  
Road Freight ◽  
Battery Packs ◽  
Adequate Evaluation

Abstract The paper deals with specific aspects regarding the current development trends of electromobility in the context of road freight transport. The current system of electric vehicles for road freight transport and the relevant investigations are based on the experience with operating trolleybuses, which have the same power supply of traction motors from the overhead traction line by means of traction pantographs. As for the future, it has not been decided yet which electromobility-related power system will be used in practice, whether the supply of electric motors from traction lines or battery packs. In the introductory chapters, the manuscript discusses the fundamental information regarding the electromobility, current projects dealing with this issue, individual aspects and attributes related to these existing power systems, and their advantages and disadvantages in terms of their usage. In the most important part of the manuscript, the adequate evaluation is performed, as well as very recommendations for future research in a given topic are proposed.

scholarly journals Advanced Hardwood Biofuels Northwest: Commercialization Challenges for the Renewable Aviation Fuel Industry

2019 ◽  
Vol 9 (21) ◽  
pp. 4644 ◽  
Author(s):  
Brian J. Stanton ◽  
Richard R. Gustafson
Keyword(s):  
Consolidated Bioprocessing ◽  
Hybrid Poplar ◽  
Biofuel Production ◽  
Aviation Fuel ◽  
Jet Fuels ◽  
Cellulosic Biofuels ◽  
The North ◽  
Fuel Industry ◽  
Private Financing ◽  
Returns On Investment

A bioenergy summit was organized by Advanced Hardwood Biofuels Northwest (AHB) to debate the barriers to the commercialization of a hybrid poplar biofuels industry for the alternative jet fuels market from the perspective of five years of AHB research and development and two recent surveys of the North American cellulosic biofuels industry. The summit showed that: (1) Growing and converting poplar feedstock to aviation fuels is technically sound, (2) an adequate land base encompassing 6.03 and 12.86 million respective hectares of croplands and rangelands is potentially available for poplar feedstock production, (3) biofuel production is accompanied by a global warming potential that meets the threshold 60% reduction mandated for advanced renewable fuels but (4) the main obstruction to achieving a workable poplar aviation fuels market is making the price competitive with conventional jet fuels. Returns on investment into biomass farms and biorefineries are therefore insufficient to attract private-sector capital the fact notwithstanding that the demand for a reliable and sustainable supply of environmentally well-graded biofuels for civilian and military aviation is clear. Eleven key findings and recommendations are presented as a guide to a strategic plan for a renewed pathway to poplar alternative jet fuels production based upon co-products, refinery co-location with existing industries, monetization of ecosystem services, public-private financing, and researching more efficient and lower-costs conversion methods such as consolidated bioprocessing.

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