Jet fuel

The work is devoted to the investigation of low-temperature properties of alternative jet fuels mixed with bio-additives derived from rapeseed oil, methanol and ethanol. For this work, a modification of conventional jet fuel from rapeseed oil, methanol and ethanol was chosen to develop alternative jet fuels. The main low-temperature characteristics -freezing point and pour point of conventional jet fuel and three types of bio-additives were identified and compared with the requirements for conventional Jet A-1 fuel. The influence of bio-additives from rapeseed oil, methanol and ethanol on low-temperature characteristics of new jet fuels has been studied and explained. The necessity of studying new technologies is grounded.

The article considers and presents the classification methods of identifying and assessing petroleum biological contamination and techniques in maintaining biological stability of hydrocarbon fuel. The article focuses on analysis, arrangement and classification of the methods for identifying petroleum biological contamination and maintaining microbiological stability of hydrocarbon fuels.

This report was developed under SBIR contract. A study on fuel additives to suppress soot emissions from gas turbines burning JP-8 was completed. The program consisted of a multifaceted approach involving experimental and computational screening tools to assess the effectiveness of multifunctional additives. The experimental program demonstrated that a laminar drop tube furnace at the University of Utah could effectively screen a large number of additives relatively rapidly and inexpensively as a function of furnace temperature, injection orifice size, injection pressure, and oxygen concentration. Additives were found to be most effective under highly oxidizing conditions. Soot reductions of over 90% were observed for metal-containing additives, know ignition enhancers, and a range of proprietary additives. Modeling capabilities for assessing the effectiveness of additives were developed. Soot models using the method of moments and sectional methods were combined with detailed kinetics models for surrogates of JP-8. the models were validated with experimental data in the literature for a number of simple fuels. Detailed Kinetic mechanisms were developed for two ignition enhancers in the study, di-tertiary butyl peroxide and 2-ethyl-hexyl-nitrate. The kinetic models were incorporated in a CFD code to evaluate diffusion flames representative of the drop tube and swirl stabilized combustor. 15. SUBJECT TERMS SBIR Report, soot, additives, turbine engine emissions, particulates, chemical kinetics, combustion, JP-8 chemistry 16. SECURITY CLASSIFICATION OF: 19a. NAME OF RESPONSIBLE PERSON (Monitor) a. REPORT

In this experimental study, the pressure dependence of the extinction strain rate of flames of jet fuel and other hydrocarbons was measured and quantified. Laminar nonpremixed opposed-jet flames of fuel/nitrogen mixtures versus oxygen-enriched air were progressively strained to extinction by lowering pressure over the pressure range 0.1 to 0.68 atm. The fuels investigated were methane; ethylene; Jet-A; n-decane; 1, 2, 4-trimethyl benzene; and blends of n-decane and 1, 2, 4-trimethyl benzene. All liquid fuels were vaporized and diluted to a mass fraction of 21.5% in nitrogen gas; the gaseous fuels were not diluted. The oxidizer was a 50/50% molar mixture of oxygen and nitrogen. The global strain rate at extinction was seen to monotonically increase with pressure in the subatmospheric pressure range explored. Overall reaction orders calculated from density-weighted extinction strain rates were between 1.3 and 2.0. Jet-A flames were extinguished at conditions similar to those for the decane/trimethyl benzene blends, indicating that these blends can serve as a surrogate for Jet-A.

SPE in combination with HPLC and fluorescence detection has been used for sensitive determination of six basic azaarenes (7,8‐benzoquinoline, 7,9‐dimethylbenz[c]acridine, 9‐amino‐1,2,3,4‐tetrahydroacridine, 9‐methylacridine, acridine, and dibenz[a,j]acridine) in aviation kerosene (jet fuel). SPE was performed in a single step using a strong cation exchange sorbent. The HPLC system consisted of C18 column with a selected detection program of optimal λexc and λem. A gradient elution with ACN and phosphate buffer (pH 6.5) at a flow rate of 1 mL/min allowed efficient and fast separation of azaarenes within 15 min. The LOD and LOQ values (S/N ratio 3:1 and 10:1, respectively) were between 0.0013 and 0.021 and from 0.0044 to 0.072 ng per injection. The calibration curves showed linear behavior from the LOQ to 250 μg/L (r2 >0.99). For the spiked concentration of 6.0 μg/L, recoveries were from 92 to 107% for jet fuel samples, except for 9‐amino‐1,2,3,4‐tetrahydroacridine, which presented...

The effect of diffusivity of petroleum products on human health in contaminated areas was investigated. The diffusivity of light naphtha, different brands of gasoline, gasoline-ethanol blends, and jet fuel were examined as a function of temperature. The diffusivities were related to the density, vapor pressure, and the types of hydrocarbons present in each product. The diffusivity of different gasoline-ethanol blends was also studied. The temperature has an effective influence on diffusivity. The increasing of atmospheric temperature means an increasing in the diffusivity and increasing in the impact of human health and especially in closed areas as hydrocarbon vapors contaminated area.

Nordic co-operation has firm traditions in politics, the economy, and culture. It plays an important role in European and international collaboration, and aims at creating a strong Nordic community in a strong Europe. Nordic co-operation seeks to safeguard Nordic and regional interests and principles in the global community. Common Nordic values help the region solidify its position as one of the world's most innovative and competitive. Ved Stranden 18 DK-1061 Copenhagen K Phone (+45) 3396 0200 www.norden.org  Nordic collaboration and policy makers should continue work towards globally applicable standards for sustainability, in line with current policies for climate change mitigation.  Explore the possibility to develop globally accepted mandatory blending levels.  Support and advocate for more streamlined and time-efficient ASTM acceptance processes of new pathways in support of sustainable jet fuel.

Nordic co-operation has firm traditions in politics, the economy, and culture. It plays an important role in European and international collaboration, and aims at creating a strong Nordic community in a strong Europe. Nordic co-operation seeks to safeguard Nordic and regional interests and principles in the global community. Common Nordic values help the region solidify its position as one of the world's most innovative and competitive. Ved Stranden 18 DK-1061 Copenhagen K Phone (+45) 3396 0200 www.norden.org  Nordic collaboration and policy makers should continue work towards globally applicable standards for sustainability, in line with current policies for climate change mitigation.  Explore the possibility to develop globally accepted mandatory blending levels.  Support and advocate for more streamlined and time-efficient ASTM acceptance processes of new pathways in support of sustainable jet fuel.

The aim of the research was to determine the possibility of co-combustion of conventional aviation fuel (JET A-1 jet fuel) with hydrogen (H 2 ). The tested miniature turbojet engine was adapted to co-combust of both fuels. The results obtained from the research provide a positive premise for the application and implementation of hydrogen co-combustion (or combustion) technology in aircraft turbojet engines, which has not yet found industrial application. Observations and research show that co-combustion of jet fuel with hydrogen helps reduce the carbon footprint of the use of turbojet aircraft engines and also reduces other harmful substances (e.g. carbon monoxide, nitrogen oxides or solid particles). During the tests, no deterioration of the engine's operating parameters was observed and the set operating parameters were maintained. To summarize, the technology of co-combustion or hydrogen combustion in miniature turbojet engines is an indicated direction in the development of pro-ecological aircraft engines.

Solvent extraction of bituminous coals has been used as a means of coproducing clean liquid transportation fuels as well as solid fuels for gasification. Coal solvents are created by hydrogenating coal tar distillate fractions to the level of a fraction of a percent, thus enabling bituminous coal to enter the liquid phase under conditions of high temperature (above 400 oC). The pressure is controlled by the vapor pressure of the solvent and the cracked coal. Once liquefied, mineral matter can be removed via centrifugation, and the resultant superheavy crude can be processed to make pitches, cokes as well as lighter products. Low emission liquefaction processes are particularly important in a scenario in which greenhouse gas mitigation is essential. Likely such scenarios will emphasize the use of technologies such as wind and nuclear power for central station power, while hydrocarbons will be increasingly reserved for liquid transportation fuel applications. Lower rank coals such as ...

Adverse climate change has forced a deeper reflection on the scale of pollution related to human activity, including in the aviation industry. As a result, fundamental questions have arisen about the characteristics of these pollutants, the mechanisms of their formation and potential strategies for reducing them. This paper provides a comprehensive overview of key technical solutions to minimize the environmental impact of aircraft engines. The solutions presented range from fuel innovations to advanced design changes and drive concepts. Particular attention was paid to sustainable aviation fuels (SAFs), which are currently an important element of the environmental strategy regulated by the European Union. It also discusses the potential use of hydrogen as a potential alternative fuel to replace traditional aviation fuels in the long term. The analysis in the article made it possible to characterize in detail possible modifications in the functioning of aircraft engines, based both on the current state of technical knowledge and on the anticipated directions of its development, which has not been a frequent issue in comprehensive research so far. The analysis shows that the type of raw material used to create SAF has a strong impact on its physical and chemical parameters and the degree of greenhouse gas emissions. This necessitates a broader analysis of the legitimacy of using a given type of fuel from the SAF group in the direction of selected air operations and areas with a higher risk of severe atmospheric pollution. These results provide the basis for further research into sustainable solutions in the aviation sector that can contribute to significantly reducing its impact on climate change.

Vegetable oils are excellent feedstock for production of diesel and jet fuels. However, catalysts and processes published in the literature do not produce drop-in fuels. One of the major problems is the selectivity and stability of the catalysts. It is vital that the hydrotreating is tested after at least 200 h on stream to measure the steady-state performance of the catalyst rather than its initial activity. The presence of aromatics is a critical issue. This study addresses specifically the issue of aromatics related to the composition of the vegetable oils. A novel Pt/Al 2 O 3 /SAPO-11 is used. Testing six different oils indicates that a certain level of poly-unsaturation of the fatty acids is required to produce relatively high aromatics content. This was further supported in specific tests of vegetable oils, fatty acids and C 16 hydrocarbons dissolved in decane. Therefore, poly-unsaturated soybean, sunflower and camelina oils produce fuels containing about 15 wt% aromatics while the content of aromatics in the product of palm or castor oils hydrotreating is 2 wt%. A tentative reactions sequence was suggested leading to triglycerides aromatization on the basis of measured dependency of hydrotreated oil products on the process space time, structure of aromatic hydrocarbons and published chemical transformations of triglycerides. Three stage processes were proposed to produce jet fuels that meet the standards. 42-48 wt% yield of the jet fuel is reported. This is a basis for commercial production of drop-in diesel and jet fuel.

This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

This is a PDF file of an article that has undergone enhancements after acceptance, such as the addition of a cover page and metadata, and formatting for readability, but it is not yet the definitive version of record. This version will undergo additional copyediting, typesetting and review before it is published in its final form, but we are providing this version to give early visibility of the article. Please note that, during the production process, errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.

Quantifying the risk of accidental ignition of flammable mixtures is extremely important in industry and aviation safety. The concept of a minimum ignition energy (MIE), obtained using a capacitive spark discharge ignition source, has traditionally formed the basis for determining the hazard posed by fuels. While extensive tabulations of historical MIE data exist, there has been little work done on ignition of realistic industrial and aviation fuels, such as gasoline or kerosene. In the current work, spark ignition tests are performed in a gaseous kerosene-air mixture with a liquid fuel temperature of 60 • C and a fixed spark gap of 3.3 mm. The required ignition energy was examined, and a range of spark energies over which there is a probability of ignition is identified and compared with previous test results in Jet A (aviation kerosene). The kerosene results are also compared with ignition test results obtained in previous work for traditional hydrogen-based surrogate mixtures used in safety testing as well as two hexane-air mixtures. Additionally, the statistical nature of spark ignition is discussed.

This study compares the flame structure of ethanol and dimethyl ether (DME) in a hot and diluted oxidiser experimentally and computationally. Experiments were conducted on a Jet in Hot Coflow (JHC) burner, with the fuel jet issuing into a 1250-K coflow at three oxygen levels. Planar measurements using OH-LIF, CH 2 O-LIF, and Rayleigh scattering images reveal that the overall spatial distribution and evolution of OH, CH 2 O, and temperature were quite similar for the two fuels. For both the ethanol and the DME flames, a transitional flame structure occurred as the coflow oxygen level increased from 3% to 9%. This indicates that the flames shift away from the MILD combustion regime. Reaction flux analyses of ethanol and DME were performed with the OPPDIF code, and ethane (C 2 H 6 ) was also included in the analyses for comparison. These analyses reveal that the H 2 /O 2 pathways are very important for both ethanol and DME in the 3% O 2 cases. In contrast, the importance of fuel-specific reactions overtakes that of H 2 /O 2 reactions when fuels are burnt in the cold air or in the vitiated oxidant stream with 9% O 2 . Unsteady laminar flamelet analyses were also performed to investigate the ignition processes and help interpret experimental results. Flamelet equations were solved in time and mixture fraction field, which was provided by non-reactive Large-Eddy Simulation (LES).

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The paper presents a fluid-porous medium model, developed for stationary 2D predictions of fluidized bed. Dense phase is considered a fixed porous medium, while gas-particle interactions and bubbling phase are modeled regarding balance of friction forces between gas and particles. Like referent measurements, predictions of lateral jet injection into the bed suggest the jet penetration length is strongly affected by fluid velocity at the nozzle outlet, while influences of the nozzle vertical position and inclination angle are not significant. Also, the fluid velocity and the nozzle vertical position exert pronounced effects on mixing rate of components (fuel and oxidizer).

Dermal penetration and absorption of jet fuels in general, and JP-8 in particular, is not well understood, even though government and industry, worldwide, use over 4.5 billion gallons of JP-8 per year. Exposures to JP-8 can occur from vapor, liquid, or aerosol. Inhalation and dermal exposure are the most prevalent routes. JP-8 may cause irritation during repeated or prolonged exposures, but it is unknown whether systemic toxicity can occur from dermal penetration of fuels. The purpose of this investigation was to measure the penetration and absorption of JP-8 and its major constituents with rat skin, so that the potential for effects with human exposures can be assessed. We used static diffusion cells to measure both the flux of JP-8 and components across the skin and the kinetics of absorption into the skin. Total flux of the hydrocarbon components was 20.3 micrograms/cm 2 /h. Thirteen individual components of JP-8 penetrated into the receptor solution. The fluxes ranged from a high of 51.5 micrograms/cm 2 /h (an additive, diethylene glycol monomethyl ether) to a low of 0.334 micrograms/cm 2 /h (tridecane). Aromatic components penetrated most rapidly. Six components (all aliphatic) were identified in the skin. Concentrations absorbed into the skin at 3.5 h ranged from 0.055 micrograms per gram skin (tetradecane) to 0.266 micrograms per gram skin (undecane). These results suggest: (1) that JP-8 penetration will not cause systemic toxicity because of low fluxes of all the components; and (2) the absorption of aliphatic components into the skin may be a cause of skin irritation.

The paper presents the results of numerical simulations of a combustion process for a pure hydrogen jet in the atmosphere of oxygen and water vapor. The research was performed using Large Eddy Simulations (LES) combined with Conditional Moment Closure (CMC) model and included the analysis of auto-and forced (spark) ignition, flame development and flame propagation. In the configuration analyzed in the study, the fuel jet issues into a hot co-flowing oxidizer stream (O 2 /H 2 O). We considered two different co-flow temperatures, 1030 K and 1045 K, and various oxidizer compositions with H 2 O mass fraction over the range of Y H2O ¼ 0:1 À 0:9 and with Y O2 ¼ 1 À Y H2O . The analyses were carried out with assuming constant 30% excess of the mass flow rate of oxygen relative to the hydrogen. It was found that: (i) the auto-ignition process occurs only for a low content of H 2 O in the coflow (Y H2O 0:5), (ii) and is additionally determined by its temperature; (iii) depending on O 2 /H 2 O proportion the flames stabilizes as attached or lifted. By alteration of Y H2 O in the oxidizer, the maximum flame temperature and the lift-off height (L H ) can be changed in the range of 1500K/3000K and L H ¼ 0/11 jet diameters, respectively.

Biomass is a promising renewable feedstock for conversion to sustainable aviation fuel (SAF) to mitigate near-term greenhouse gas (GHG) emissions. Through metabolic engineering, sugars derived from pretreated and hydrolyzed cellulose and hemicellulose can be directly fermented to isoprene and catalytically upgraded to 1-4-dimethylcyclooctane (DMCO), an environmentally beneficial and high performance alternative to petroleum-based jet fuel. Cellulosic sugars may allow for greater GHG emission reduction compared to first generation sugars and meet scaling needs to reduce dependence on petroleum-based kerosene. Here, we assess the environmental impact and economic feasibility of utilizing direct isoprene fermentation from residual biomass sugars as an intermediate step in the production of DMCO via life cycle assessment (LCA) and techno-economic analysis (TEA). We use chemical process modeling to simulate the conversion of sugars from biomass to isoprene, dimerization to dimethylcyclooctadiene (DMCOD) and catalytic hydrotreatment to DMCO. The bottom-up process model serves as the basis for constructing the life cycle inventory to assess environmental impacts and to predict economic feasibility. Results show a GHG intensity of 7.2 gCO 2 e MJ -1 that is significantly lower than that of current petroleum jet (89 gCO 2 e MJ -1 ) when using Zea mays L. residue (corn stover) as feedstock. The TEA indicated that the target costs have the potential to be competitive with a minimum fuel selling price of DMCO between $1.01 and $1.32 per L. Direct fermentation of isoprene could improve the overall process efficiency and reduce energy consumption, while also enhancing the environmental sustainability of the process.

Oil diffusion flames are used in diverse industrial applications. Their characteristics, stability, and exhaust emissions are very much dependent on the way and the degree of mixing. In that respect they suffered from the existence of a sooty base due to the slower rate of fuel vaporization together with the deficiency of oxidant availability at the flame core region (yellowish color), leading to high exhaust emissions of unburned hydrocarbons and CO. Nonetheless, their stabilization through a central recirculation zone (via a stabilizer disk or a vane swirler) results in the elongation of the reactants residence time, resulting in the creation of local hot spots, giving higher NOx exhaust emissions. The present paper introduces a new methodology that relied on the incorporation of multiple air injection jets onto the spray flame core base region to accelerate fuel vaporization and rapid mixture formation to improve the overall combustion efficiency and exhaust emissions. In that respect, focus is given to examining the optimum location of the air injection jets (at a fixed load, constant jet momentum, and angle). Results demonstrate significant improvements in oil diffusion flame performance through reduced flame length, temperature uniformity, soot oxidation, and lower pollutant emissions. The combustion mode shifts from a diffusion flame to a lean partially premixed flame, or a moderate or intense low-oxygen dilution combustion regime based on air injection jet parameters. The optimal location for air injection jets is found to be at the exit plane of the premix chamber (5 cm from the stabilizer disk). This injection position is associated with superior combustion efficiency, minimized carbon monoxide emissions, and a permissible level of nitrogen oxide (NOx) emissions. While applicable to gas turbine combustion and other oil diffusion flames, further studies and simulations are necessary to optimize and validate this promising technique.

Exposure to fuels continues to be a concern in both military and general populations. The aim of this study was to examine effects of in vivo rat repeated exposures to different types of jet fuel utilizing microelectrode arrays for comparative electrophysiological (EP) measurements in hippocampal slices. Animals were exposed to increasing concentrations of four jet fuels, Jet Propellant (JP)-8, Jet A, JP-5, or synthetic Fischer Tropsch (FT) fuel via whole-body inhalation for 20 d (6 hr/d, 5 d/week for 28 d) and synaptic transmission as well as behavioral performance were assessed. Our behavioral studies indicated no significant changes in behavioral performance in animals exposed to JP-8, Jet A, or JP-5. A significant deviation in learning pattern during the Morris water maze task was observed in rats exposed to the highest concentration of FT (2000 mg/m 3). There were also significant differences in the EP profile of hippocampal neurons from animals exposed to JP-8, Jet A, JP-5, or FT compared to control air. However, these differences were not consistent across fuels or dose dependent. As expected, patterns of EP alterations in brain slices from JP-8 and Jet A exposures were more similar compared to those from JP-5 and FT. Further longitudinal investigations are needed to determine if these EP effects are transient or persistent. Such studies may dictate if and how one may use EP measurements to indicate potential susceptibility to neurological impairments, particularly those that result from inhalation exposure to chemicals or mixtures.

Hydrotreated renewable jet fuel (HRJ) derived from crop oils has been commercially demonstrated, but full-scale production has been hindered by feedstock costs that make it more costly than petroleumbased fuels. Maintaining low feedstock costs while developing crops attractive to growers will be key to producing affordable HRJ and creating a dependable supply. Several Brassica oilseed species could potentially serve as feedstock, but genotypes agronomically and economically well suited for a given region will likely vary with environment and current cropping systems. The objectives of this study were to evaluate seed and seed oil yields of 12 summer annual Brassica genotypes representing six different species [Brassica napus L., Brassica rapa L., Brassica juncea L., Brassica carinata L., Sinapis alba L., and Camelina sativa (L.) Crantz.] and identify environmental factors that might limit their growth and oil production. The study was conducted during 2013 and 2014 in west central Minnesota, U.S. on a Barnes loam soil. This study is part of a larger project focused on evaluating the same set of oilseeds across the major wheat (Triticum aestivum L.) growing areas of the U.S. Seed yields for the 12 springsown crops in Minnesota ranged from 1058 to 3718 kg ha −1 in 2013 and 515 to 2020 kg ha −1 in 2014. The range in seed oil yield was 287-1588 kg ha −1 in 2013 and 210-885 kg ha −1 in 2014. Plant lodging was a serious issue in 2013, but it varied widely among genotypes. In 2014, which was characterized by an abnormally wet spring, disease infection {most likely white leaf spot [Pseudocercosporella capsellae (Ellis & Everh.) Deighton 1973]} and flea beetle [Phyllotreta cruciferae (Goeze)] feeding led to plant damage, but these were primarily confined to certain Brassica napus cultivars. In west central Minnesota, certain B. napus canola lines and B. carinata produced the greatest seed and oil yields. B. carinata was the latest maturing species in the study, produced the highest biomass, and tended to have low harvest indices, indicating ample room for yield improvement. For any given ecoregion, striking a balance among crop yield, agricultural input costs, and optimum species/cultivar choice for a particular cropping system will be important for providing a reliable and affordable feedstock for HRJ. Published by Elsevier B.V. ଝ Mention of trade names or commercial products in this publication is solely for the purpose of providing specific information and does not imply recommendation or endorsement by the U.S. Department of Agriculture. USDA is an equal opportunity provider and employer.

Solid-oxide fuel cells with ceria, ceria-Cu, and ceria-Rh anode were demonstrated to generate stable electric power with waste vegetable oil through direct oxidation of the fuel. The only pre-treatment to the fuel was a filtration to remove particulates. The performance of the fuel cell was stable over 100 h for the waste vegetable oil without dilution. The generated power was up to 0.25 W cm −2 for ceria-Rh fuel cell. This compares favorably with previously studied hydrocarbon fuels including jet fuels and Pennsylvania crude oil.

The aim of the research was to determine the possibility of co-combustion of conventional aviation fuel (JET A-1 jet fuel) with hydrogen (H 2). The tested miniature turbojet engine was adapted to co-combust of both fuels. The results obtained from the research provide a positive premise for the application and implementation of hydrogen co-combustion (or combustion) technology in aircraft turbojet engines, which has not yet found industrial application. Observations and research show that co-combustion of jet fuel with hydrogen helps reduce the carbon footprint of the use of turbojet aircraft engines and also reduces other harmful substances (e.g. carbon monoxide, nitrogen oxides or solid particles). During the tests, no deterioration of the engine's operating parameters was observed and the set operating parameters were maintained. To summarize, the technology of co-combustion or hydrogen combustion in miniature turbojet engines is an indicated direction in the development of pro-ecological aircraft engines.

Due to different motivations, including the interest in reducing the dependency on fossil fuel and environmental implications, drop-in biofuels are a reality in today's commercial aviation. This paper summarizes the state-of-the-art of biomass-origin kerosene certification and provides references to the commercial flights performed so far by all airlines around the world. Results prove that the normal operation of the flights using the drop-in biofuel do not experience any repercussion in the performance in both engine and maintenance.

Since its fimnding, NASA has been dedicated to the advancement of aeronautics and space science. The NASA Scientific and Technical Information (STI) Program Office plays a key part in helping NASA maintain this important role. The NASA STI Program Office is operated by I,angley Research Center, the lead center for NASA's scientific and technical information. The NASA STI Program Office provides access to the NASA STI Database, the largest collection of aeronautical and space science STI in the world. The N ' Program Office is also 'ASA s institutional mechanism for disseminating the results of its research and development activities. These results are published by NASA in the NASA STI Repoll Series, which includes the following repoi_ types: TECHNICAl, P[ ;BI,ICATION. Reports of completed research or a major significant phase of research that present |he resul|s of NASA programs and include extensive data or theoretical analysis. Includes compilations of significant scientific and technical data aald inlbrmation deemed to be of continuing reference vat ue. NASA' s counterpart of peer-reviewed formal professional papers but has less stringent limitations on manuscript length and extent of graphic presentations.

High-density polycycloalkanes were first produced with cellulose by a highly integrated route that features a selective hydrogenolysis of cellulose to 2,5hexanedione under mild conditions, followed by the direct synthesis of polycycloalkanes with 2,5-hexanedione and hydrogen over a dual-bed catalyst system. The polycycloalkane mixture as obtained has a high density (0.88 g mL À1) and low freezing point (225 K). In real application, they can be used as advanced aviation fuel or additives to improve the volumetric heat values of conventional aviation fuels.

In order to further reduce the sulfur content in liquid hydrocarbon fuels (gasoline, diesel fuel and jet fuel) for producing ultra-clean transportation fuels and for fuel cell applications, we explored a new desulfurization process by selective adsorption for removing sulfur (SARS). An adsorbent was developed and used for adsorption desulfurization of diesel fuel, gasoline and jet fuel at room temperature. The results indicate that the transition metal-based adsorbent developed in this work is effective for selectively adsorbing the sulfur compounds, even the refractory sulfur compounds in diesel fuels. The SARS process can effectively remove sulfur compounds in the liquid hydrocarbon fuels at ambient temperature under atmospheric pressure with low investment and operating cost. On the basis of the present study, a novel integrated process is proposed for deep desulfurization of the liquid hydrocarbon fuels in a future refinery, which combines a selective adsorption (SARS) of the sulfur compounds and a hydrodesulfurization process of the concentrated sulfur fraction (HDSCS). The SARS concept may be used for on-site or on-board removal of sulfur from fuels for fuel cell systems.

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Adsorbents based on transition metal ion-exchanged Y zeolites (with Cu, Ni, Zn, Pd, and Ce ions) were synthesized and evaluated for the adsorptive desulfurization of a model jet fuel (MJF) and a real jet fuel (JP-8). Among the adsorbents tested, Ce-exchanged Y zeolites exhibited better adsorption capacity of about 10 mg of sulfur/g of adsorbent at 80 °C with a MJF containing 510 ppmw sulfur. The same adsorbent exhibited a sulfur adsorption capacity of about 4.5 mg/g for the real JP-8 jet fuel containing about 750 ppmw sulfur. Desulfurization of MJF under flow conditions at 80 °C showed a breakthrough capacity of about 2.3 mg/g of adsorbent. Ce-exchanged zeolites exhibited higher selectivity for sulfur compounds as compared to the selectivity of aromatics, for which a comparative study indicated that the sulfur compounds are adsorbed over Ce-exchanged Y zeolites via direct sulfur-adsorbent (S-M) interaction rather than via π-complexation. While the selectivity for 2-methyl benzothiophene (2-MBT) was higher in the static adsorption studies, the adsorption selectivity decreased in the order 5-methyl benzothiophene (5-MBT) > benzothiophene (BT) > 2-MBT under dynamic conditions. This trend was correlated to the electron density on sulfur atoms derived from computer-aided molecular orbital calculations.

Fuel injection systems in modern diesel engines are designed and built to comply with very stringent environmental standards. They should also meet the highest level of fuel economy. Drivability, rapid response and easy and accurate control are a common demand. Changing the fuel characteristics could affect the performance of the fuel injection system. This study focuses on the evaluation of fuel spray characteristics of straight used cooking oil (SUCO) and its blends with petroleum diesel (PD) as a surrogate for pure PD. Used cooking oil blends have quite different physical properties from those of pure PD. Data for the lower heating value (LHV), density and viscosity were obtained from laboratory analysis. These data were merged with the physical and thermodynamic conditions of the diesel engine of interest to evaluate the dynamic behaviour of the fuel jet in 360° of crank rotation namely, the compression stroke, and the power stroke including the injection process. Engine operati...

In this paper, the criteria for determining the composition and physicochemical properties of aviation kerosene were formulated. The data on the physicochemical properties of known kerosene surrogates were systematized and classified. The main classes of individual chemical components of aviation kerosene were determined, and the main representatives of these classes which were used in the preparation of surrogates, were investigated. Four- and six-component kerosene substitutes are proposed. The physical properties of the developed surrogates were validated according to the flow characteristics and the spray angle of the flame of a centrifugal fuel nozzle. The dependence of the flame speed on the composition of the mixture of developed kerosene surrogates was determined. The results of determining the composition of combustion products during the combustion of TS-1 brand aviation kerosene and its surrogates in a model combustion chamber were compared.

In the last years, several alternative aviation jet fuels have been approved as a response to worldwide concerns on adverse environmental effects of greenhouse gas emissions. However, comprehensive emissions studies are not part of the approval process. When burning a jet fuel, the exhaust gases are a mixture of gaseous specious including aromatics and non-gaseous species, particles, and soot. In addition, these species may affect the growth and lifetime of contrails known to be of influence on the climate due to their radiative forcing. Within this context, the use of synthetic aviation fuels may offer several advantages, going beyond reduced CO 2 emissions. These issues were addressed by studying the combustion of synthetic jet fuels taking into account their individual composition. An overview of what is known on their emission pattern was presented. Mostly, the same general trends were reported for the emissions of interest, for the fuels considered and at the power settings selected, with no adverse emissions effects. In particular, less soot particle emissions were reported, in mass and in number concentration, for GtL, HEFA, and farnesane. Moreover, a strong link between the amount and type of aromatics content of a jet fuel and soot emissions was observed.

In this study, the MOF-derived hollow void catalyst Co@C(Z-d)@Void@CeO 2 is promoted using ruthenium (Ru) for application as an efficient catalyst for the Fischer Tropsch synthesis (FTS). The reducibility of Co active sites is significantly improved in the presence of the Ru nanoparticles (NPs), leading to a higher degree of reduction (DOR) and dispersion. Hence, the catalyst performance, i.e., CO conversion, was enhanced by 56% at 12 bar in comparison with the catalyst without Ru. Moreover, the Ru-doped catalyst promotes the jet fuel production yields more than the other FTS products. Remarkably, both the experimental results and the molecular dynamics (MD) simulation confirmed the desired effects, where the calculated Gibbs free energy (DG) of paraffinic hydrocarbon formation, particularly in the jet fuel range, was lower in the presence of Ru. The thermal stability of the Ru-doped catalyst was characterized by thermogravimetric analysis (TGA) and confirmed by a dramatic low-performance loss of 4.2% at 17.5 bar during TOS of 192 h.

The objective of this research was to develop a mathematical description of uptake of aromatic and aliphatic hydrocarbons into the stratum corneum of human skin in vivo. A simple description based on Fick's Laws of diffusion was used to predict the spatiotemporal variation of naphthalene, 1-and 2-methylnaphthalene, undecane, and dodecane in the stratum corneum of human volunteers. The estimated values of the diffusion coefficients for each chemical were comparable to values predicted using in vitro skin systems and biomonitoring studies. These results demonstrate the value of measuring dermal exposure using the tape-strip technique and the importance of quantifying of dermal uptake.

This paper investigates the effect of fluid catalytic cracking (FCC) feed hydrotreatment and its severity increase on product yields and quality obtained in a commercial and a laboratory MAT FCC units. The hydrotreatment of Ural heavy vacuum gas oil reduces not only sulfur, nitrogen, Conradson carbon and metals content in the FCC feed but also increases the mononuclear aromatic hydrocarbons content by 8% absolute at almost no change in the total aromatics content. Regardless of this 8% increase of the mononuclear aromatics in the hydrotreated FCC feed the conversion increase in both commercial and laboratory MAT units was only 2%. The severity increase in the FCC feed hydrotreater leads to a higher conversion in the FCC, higher hydrogen transfer rate that results in higher isobutane/butylenes ratio, lower gasoline olefins content, and higher gasoline motor octane number. The hydrotreatment of the Ural heavy vacuum gas oil exhibited the same changes in FCC catalyst selectivities: lower coke and LCO selectivities and higher gasoline selectivity in both commercial riser FCC unit that has between 2 and 3 s time on stream, and the fixed bed reactor MAT unit, that has 30 s time on stream.

Biomass-based Fischer−Tropsch paraffin mixtures, having C 16 −C 46 and C 11 −C 45 carbon number range, were hydrocracked over platinum-supported beta, ZSM-5, and mordenite catalysts. The aim of the study was to investigate the effects of the feedstock composition, the process parameters, and the catalyst properties (acidity and zeolite structure) on the C 21 + conversions, the product yields, and the isoparaffin contents. It was stated that lower C 21 + conversions and higher JET and diesel fuel yields can be obtained for feedstock comprising C 11 −C 45 hydrocarbons. Under identical reaction conditions, the activity order of the catalysts was Pt/H-beta > Pt/H-ZSM-5 > Pt/H-mordenite. This order corresponds to the relative number of accessible acid sites. Among the tested catalysts, platinum-supported beta zeolite showed the highest hydroisomerization activity; meanwhile, in the pores of Pt/ZSM-5 and Pt/H-mordenite, diffusion constraints were observed. As the product of hydrocracking valuable gasoline, JET and diesel fuels having high hydrogen content and excellent burning properties were produced.

The present-day situation in civil aviation is discussed. Taking into account limitation of crude oil resources for jet fuel production and worsening of ecological situation, tendency to transition to alternative fuels is presented. Perspectives of Ukraine and Poland in production and application of alternative jet fuels are figured out. The main attention is paid to reveal possibilities of these countries for production of jet biofuels derived from plant oils. The potential of biofuel production from various feedstocks is presented and analyzed. Advantages of oil-derived biofuel production and application are discussed.

Biodiesel was efficiently produced from biomass fatty acids using renewable gas H 2 and a reusable heterogeneous catalyst under low-energy-consumption microwave conditions. As the decarboxylation of fatty acids to alkanes is an important transformation in the production of bio hydrofined diesel (BHD) and jet fuel, we herein report the development of a highly active and reusable Rh nanoparticle catalyst supported by a silicon nanowire array (SiNA-Rh) and its application in the decarboxylation of fatty acids to alkanes under mild conditions. More specifically, SiNA-Rh (500 mol ppm) selectively promoted the hydrogenative decarboxylation reaction at 200 °C under microwave irradiation (~40 W) in a H 2 atmosphere (10 bar) to afford the corresponding alkanes in high yields selectively. The only co-product observed was carbon monoxide, an important and essential staple for the chemical industry. Importantly, carbon dioxide formation was not observed. Moreover, the aldehydes were efficiently converted to alkanes by SiNA-Rh, and this catalyst was reused 20 times without any loss in catalytic activity. Finally, to investigate the effects of microwave irradiation on the enhancement of this chemical transformation based on the Si nanorod structures present in the SiNA-Rh catalyst, the effect of the microwave electric field and magnetic field in the microwave to the reaction was experimentally investigated, and the spatial distribution of the electric field intensity around the surface of the Si nanostructure was simulated using the Finite Element Method.

Currently, the conversion of biomass to produce high-valued biofuels such as biodiesel and biojet fuel has attached booming interests, when used for partial replacement of petroleum fuels in different ratios is a promising solution due to the problem of depleting petroleum reserves and environmental purposes. Non-edible Jatropha oil can be transformed to biofuel when subjected to were hydrocracking at hydrogen pressure using an activated natural clay as a catalyst in a high pressure batch reactor. The type of product and its quality and quantity depend on the process conditions such as reaction time, temperature, and catalyst type, form, and amount. The present work aims to study the hydrocracking process of Jatropha oil at different operating conditions. The catalyst is characterized using SEM, FTIR, XRF, and XRD. The effect of process conditions variation have been studied and discussed. The results showed the highest yield of 40% bio-jet fuel was achieved at a temperature of 350 °C, H 2 pressure of 4 bar, and reaction time of 18 min. the bio-jet fuel products were tested and their specifications were conformed to ASTM D1655 specifications, viz the freezing point (−56 °C), the flash point (53 °C), and existent gum content (5.9 mg/100 ml). Abbreviations H 2 Hydrogen gas B The Egyptian Bentonite clay MB Modified Bentonite clay ASTM American Society for Testing and Materials XRF X-ray fluorescence XRD X-ray Powder Diffraction FTIR Fourier-transform infrared spectroscopy BET Brunauer, Emmett and Teller surface area Several challenges face the demand and supply of energy in the world. The increase in petroleum fuel consumption worldwide affects fossil fuel reserves. The daily global total consumption of petroleum reached 99.56 million barrels in 2022. The estimated petroleum oil reserves will be drained in less than fifty years, at the current consumption rate of 2.7% annually 1,2. Also, the emissions that are exhausted from fossil fuels combustion are large contributors to global warming and environmental pollution 3-5. Environmental awareness, depletion of fossil fuels and the increase in energy consumption and price‫‬ are the main factors leading to the search for alternative energy resources to substitute fossil‫‬ fuels 4,6-8. Renewable energy sources decrease the effect of greenhouse gases and are superior to fossil fuels with respect to their lower SO x , CO , and CO 2 emissions 9. Representative renewable energy source technologies include fuel‫‬ cells, hydropower, solar power, geothermal energy, wind power, biofuel, and hydrogen production 10,11. Biojetfuel is‫‬ one of the most important sources of renewable and green energy expected to gradually replace fossil fuels in the near future with increased blending ratios. It is anticipated to reach 25% in 2020, 30% in 2030, and 50% in 2050 12-15. Biofuels can be produced from several agricultural raw materials, through different production methods depending on the required final products and feedstock 16. These are mainly vegetable oil based and biomass. Vegetable oil-based feedstock includes edible and non-edible oils, waste cooking oil, jatropha, jojoba, rapeseed, castor and microalgal oil. Biomass feedstock includes waste materials, aquatic biomass, energy crops, and forest products 9,10,14,17 .