Download Free Effect Of Two Fluorocarbon Lubricity Additives Upon The Thermal Stability Of An Advanced Hydrocarbon Jet Fuel Book in PDF and EPUB Free Download. You can read online Effect Of Two Fluorocarbon Lubricity Additives Upon The Thermal Stability Of An Advanced Hydrocarbon Jet Fuel and write the review.

Two fluorocarbon lubricity additives were tested in the Minex heat exchanger to determine their effect upon the thermal stability of a highly refined jet fuel. The jet fuel without additives and the fuel with a standard metal deactivator additive were tested first to provide a base line for testing with the lubricity additives. The results show that the additive-free jet fuel would not degrade the heat transfer efficiency in a Minex heat exchanger at 680 F. The addition of the metal deactivator N, N' - disalicylidene - 1, 2 - propane diamine, had no effect upon the thermal stability of the fuel but the fluorocarbon lubricity additives would degrade thermal stability. Additive A changed thermal stability from greater than 680 F to 600 F, and Additive B decreased the break point to 650 F. Although there was an adverse effect upon thermal stability, the jet fuel with the fluorocarbon additive is still usable for modern high speed aircraft.
Various aspects of the thermal stability problem associated with the use of broadened-specification and nonpetroleum-derived turbine fuels are addressed. The state of the art is reviewed and the status of the research being conducted at various laboratories is presented. Discussions among representatives from universities, refineries, engine and airframe manufacturers, airlines, the Government, and others are presented along with conclusions and both broad and specific recommendations for future stability research and development. It is concluded that significant additional effort is required to cope with the fuel stability problems which will be associated with the potentially poorer quality fuels of the future such as broadened specification petroleum fuels or fuels produced from synthetic sources.
The two hydrocarbon structures exhibiting the most promise as candidate high temperature fuels are the alkyl-substituted monocyclics and the alkyl substituted condensed bicyclics. For specialized fuels, the isoparaffin structure best suits the requirements for a weight-limited fuel application whereas for an extreme high density fuel the condensed tricyclic structure exhibits the best compromise of properties. The preliminary results of a vapor fuels study indicate that the basic condensed bicyclic structure once again offers the most promise for an advanced vapor fuel. Research has indicated that a vapor fuel will extend the flight speed of advanced systems beyond mach 5. For greater speeds or for desirable additional cooling below Mach 5, a type of endothermic fuel will be required. The primary contribution of the endothermic fuels program is that the feasibility of conducting this type of reaction under conditions to be encountered in advanced air-breathing systems is established and that the reaction products will perform satisfactorily in the combustor.
NAVAIRSYSCOM has evaluated the individual benefits of 3 different thermal stability improving additives (TSIAs) in jet fuel using 2 separate, small-scale test devices - one laminar flow and the other turbulent. Both systems pump fuel at constant flowrate and use stainless steel tubes that are heated to maintain the bulk fuel at a constant, elevated test temperature. The laminar device has an inside diameter of 0.1 in. (0.262 cm) and an approximate Reynolds No. of 200, whereas the turbulent has an inside diameter of 0.01 in. (0.0254 cm) and a Reynolds No. of 13,000. The results have shown that all 3 TSIAs, when test at their maximum dose levels, reduce the amount of thermal deposits (measured via carbon burnoff) in both flow regimes for 3 different base fuels tested. Both units rank the level of thermal stability in the same order for the 3 baseline fuels tested. In addition, both devices show that Betz 8Q462. is the most effective additive of the 3 tested, with MDA demonstrating almost similar performance in controlling deposit formation. Furthermore, Betz 8Q406 was not as effective as the 2 other additives, but a change in its formulation by the addition of 2 mg/l MDA (to produce 8Q462) greatly improved its performance in both test devices, but most notably in the laminar unit. However, one exception had occurred when MDA was added to one of the test fuels (Tank 20122), which caused an increase in deposition compared to the neat fuel when tested in the turbulent unit. Overall, the combination of the accelerated test conditions in the turbulent unit of higher bulk fuel temperate, higher flowrate, turbulent flow (i.e., flatter temperature profile across the tub ID), and shorter residence time make this a more severe test when compared to the laminar device.
The effects of fuel additives and naturally occurring fuel components and impurities on the lubricity of JP-5 were determined. The ball-on-cylinder machine was used as a lubricity tester. Naturally occurring hydrocarbon compounds had very little effect on the lubricity of JP-5. Corrosion inhibitors, organic acids and nitrogen containing compounds were found to improve lubricity while sulfur compounds, non-acid oxygen containing compounds and anti-oxidants had little or no effect on lubricity. The compounds that were effective lubricity improvers did so by keeping dissolved oxygen from reaching the metal surface of the ball-on-cylinder machine and reacting there.
The reliability of a small-scale (5-ml Bomb), static thermal stability test procedure, based on optical measurements of fuel compositional changes induced by thermal stressing was established. Five aviation turbine fuels, covering a range in inherent thermal stabilities from 300F to 700F, were studied to determine the effect of storage duration in sealed drums at 40F ambient, 130F and 180F on their thermal stability quality. Four of the fuels, representing straight-run production fuels were not susceptible to deterioration at these storage temperatures through the storage periods investigated. A fifth fuel, synthetic HF alkylate, showed a maximum loss of about 100F at all storage temperatures except 40F. Susceptibility is attributed to its relatively high olefinic content (about 2 volume per cent) and the presence of possible reactive tertiary hydrogen components. Removal of dissolved oxygen to less than one part per million prior to storage prevented deterioration of the HF alkylate fuel and improved the thermal stability of the poorer quality fuels. Information was also obtained on the effects of various contaminants that might be picked up during handling and storage on thermal stability of one fuel.