Fischer-Tropsch Synthetic Paraffinic Kerosene Research Articles

Potential for biojet production from different biomass feedstocks and consolidated technological routes: a georeferencing and spatial analysis in Brazil

AbstractThis paper assesses the biojet fuel production potential in Brazil. It evaluates feedstock availability by applying a georeferencing analysis, and determines the cost‐effectiveness and greenhouse gas (GHG) emissions of selected production routes throughout their entire life cycle. This study identifies and locates Brazilian hotspots in terms of bioenergy availability and proximity to the main sites of fuel consumption and handling in the country. Findings show that the biomass availability for each crop in the hotspots would be sufficient to feed the biojet conversion plants proposed in this study. The biojet production potential in the hotspots would represent 48% of the country's jet fuel consumption in 2014, allowing the current certificated 50% blend with conventional fuel. The major biomass hotspots are close to airport and fuel logistic basis. However, even with a US$ 200.tCO–1 2 tax, hydroprocessed esters and fatty acids (HEFA) biojet is far from being competitive with petroleum‐based jet fuel, whereas the Fischer–Tropsch synthetic paraffinic kerosene (FT‐SPK) route may produce a competitive biojet. One possible pathway to incentivize biojet fuel production in Brazil would be, first, to implement carbon taxes that would allow the development of smaller plants. Then, with technological learning and larger production scales, it would be possible to reduce or even eliminate the carbon taxes. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd.

The blending effect on the sooting tendencies of alternative/conventional jet fuel blends in non-premixed flames

In order to study the blending effect on sooting tendencies for practical alternative/conventional jet fuel blends, the present study has investigated soot formation in non-premixed flames of Jet-A blended with three alternative jet fuels (AJFs), i.e., Hydroprocessed Esters and Fatty Acids from camelina (HEFA-Camelina), Fischer-Tropsch Synthetic Paraffinic Kerosene (FT-SPK), and Alcohol-to-Jet (ATJ). The smoke points of the AJF/Jet-A blends were measured in a wick lamp per ASTM D1322 standard, and their Threshold Sooting Indices were derived. Soot volume fraction profiles of the AJF/Jet-A fuel blends were also measured using the laser-induced incandescence diagnostics in the counterflow non-premixed flames. The effects of AJF blending ratio, strain rate, and reactant concentration on the soot formation were examined. The experimental results show that the Threshold Sooting Indices of the AJF/Jet-A blends exhibit a linear relationship with AJF mole fraction. While the maximum soot volume fractions of fuel blends show a fairly linear relationship with AJF blending ratio, the nonlinearity becomes prominent at high strain rates and low reactant concentrations. Comparing the three AJF/Jet-A fuel blends, the sooting tendencies are ranked as ATJ/Jet-A > FT-SPK/Jet-A > HEFA-Camelina/Jet-A. Correlations of the maximum soot volume fraction with aromatics content, hydrogen content, smoke point, and Threshold Sooting Index were all also examined. It is found that neither aromatics content nor hydrogen content can correlate with the maximum soot volume fraction for all the fuel blends at a given condition; conversely, smoke point shows a nonlinear correlation and Threshold Sooting Index shows an approximately linear correlation with the maximum soot volume fraction for all the fuel blends. It is suggested that the different sooting tendencies of AJF/Jet-A blends are mainly caused by the different sooting propensities of individual AJFs, which are strongly dependent on their distinct paraffinic compositions.

Toxicity and occupational exposure assessment for Fischer-Tropsch synthetic paraffinic kerosene

ABSTRACTFischer-Tropsch (FT) Synthetic Paraffinic Kerosene (SPK) jet fuel is a synthetic organic mixture intended to augment petroleum-derived JP-8 jet fuel use by the U.S. armed forces. The FT SPK testing program goal was to develop a comparative toxicity database with petroleum-derived jet fuels that may be used to calculate an occupational exposure limit (OEL). Toxicity investigations included the dermal irritation test (FT vs. JP-8 vs. 50:50 blend), 2 in vitro genotoxicity tests, acute inhalation study, short-term (2-week) inhalation range finder study with measurement of bone marrow micronuclei, 90-day inhalation toxicity, and sensory irritation assay. Dermal irritation was slight to moderate. All genotoxicity studies were negative. An acute inhalation study with F344 rats exposed at 2000 mg/m3 for 4 hr resulted in no abnormal clinical observations. Based on a 2-week range-finder, F344 rats were exposed for 6 hr per day, 5 days per week, for 90 days to an aerosol-vapor mixture of FT SPK jet fuel (0, 200, 700 or 2000 mg/m3). Effects on the nasal cavities were minimal (700 mg/m3) to mild (2000 mg/m3); only high exposure produced multifocal inflammatory cell infiltration in rat lungs (both genders). The RD50 (50% respiratory rate depression) value for the sensory irritation assay, calculated to be 10,939 mg/m3, indicated the FT SPK fuel is less irritating than JP-8. Based upon the proposed use as a 50:50 blend with JP-8, a FT SPK jet fuel OEL is recommended at 200 mg/m3 vapor and 5 mg/m3 aerosol, in concurrence with the current JP-8 OEL.

Impact of Alternative Jet Fuels on Engine Exhaust Composition During the 2015 ECLIF Ground-Based Measurements Campaign.

The application of fuels from renewable sources ("alternative fuels") in aviation is important for the reduction of anthropogenic carbon dioxide emissions, but may also attribute to reduced release of particles from jet engines. The present experiment describes ground-based measurements in the framework of the ECLIF (Emission and Climate Impact of Alternative Fuels) campaign using an Airbus A320 (V2527-A5 engines) burning six fuels of chemically different composition. Two reference Jet A-1 with slightly different chemical parameters were applied and further used in combination with a Fischer-Tropsch synthetic paraffinic kerosene (FT-SPK) to prepare three semi synthetic jet fuels (SSJF) of different aromatic content. In addition, one commercially available fully synthetic jet fuel (FSJF) featured the lowest aromatic content of the fuel selection. Neither the release of nitrogen oxide or carbon monoxide was significantly affected by the different fuel composition. The measured particle emission indices showed a reduction up to 50% (number) and 70% (mass) for two alternative jet fuels (FSJF, SSJF2) at low power settings in comparison to the reference fuels. The reduction is less pronounced at higher operating conditions but the release of particle number and particle mass is still significantly lower for the alternative fuels than for both reference fuels. The observed correlation between emitted particle mass and fuel aromatics is not strict. Here, the H/C ratio is a better indicator for soot emission.

Soot formation in non-premixed counterflow flames of conventional and alternative jet fuels

With increasing concerns over fuel cost, environmental pollutions, and energy security, the development of alternative fuels from renewable sources has gained considerable attention in the past decade. To evaluate the sooting propensities of representative conventional and alternative jet fuels, the present study has investigated soot formation in non-premixed combustion for three conventional reference jet fuels, i.e., Jet-A, JP-8, and JP-5, and three selected alternative jet fuels, i.e., Fischer-Tropsch Synthetic Paraffinic Kerosene (FT-SPK), Hydroprocessed Esters and Fatty Acids from camelina (HEFA-Camelina), and Alcohol-to-Jet (ATJ). The soot volume fraction profiles of these jet fuels in the atmospheric-pressure counterflow non-premixed flame configuration were measured using Laser-Induced Incandescence technique. In addition, the effects of global strain rate and reactant concentration on soot formation were investigated. At the same stoichiometric mixture fraction, the experimental results show that the sooting level increases with increasing fuel and O2 concentrations, while it decreases with increasing global strain rate, as expected. It is also worth noting that the three alternative jet fuels tested demonstrated greater sensitivity to variations in global strain rate and reactant concentration, as compared to the three conventional jet fuels. Based on the measured soot volume fractions, the sooting propensity of the six jet fuels are ranked as follows: JP-5>Jet-A>JP-8>ATJ>FT-SPK>HEFA-Camelina. The observed ranking is consistent with the aromatics content in each jet fuel except when comparing FT-SPK and ATJ. While ATJ has a lower aromatics content than FT-SPK, it contains much heavier hydrocarbon components, thereby leading to higher sooting propensity. Furthermore, the correlations of soot volume fraction with aromatics content and hydrogen content are examined for all six jet fuels. Although such correlations work well for the three conventional jet fuels, the present results suggest that they cannot be directly transferable to the alternative jet fuels, as these alternative fuels are composed of negligible amounts of aromatics, as well as composed of distinct chemical compositions.

Analysis of emission characteristics of gas turbine engines with some alternative fuels

ABSTRACTThe paper concerns the comparative analysis of combustion characteristics of different alternative fuels such as Fischer-Tropsch Synthetic Paraffinic Kerosene (FT-SPK), cryogenic methane, bioethanol, biomethanol, biobutanol, dimethyl ether, biodiesel and conventional aviation kerosene Jet-A as well as analysis of emissions of NOx, CO, CO2, H2O, HNOy (y = 2,3) and organics for gas turbine engine operating on these fuels. The analysis has shown that the usage of all considered alternative fuels results in the increase of H2O emission, compared to kerosene-fueled combustor, and, as consequence, in the growth of water vapor supersaturation that can increase the rate of the H2O vapor condensation and enhance the formation of contrails and cirrus clouds in the atmosphere. The usage of all considered alternative fuels except FT-SPK, cryogenic methane and dimethyl can increase the CO2 emission compared to using of kerosene. Emission of N-containing species can be reduced upon the usage of considered alternative fuels, except dimethyl ether, for which one can expect the increase in the emissions of HNO2 and HNO3 approximately by 10%. The emission of CO decreases for all fuels except biodiesel. The major decrease can be achieved upon the replacement of kerosene to bioethanol.

REVIEW OF TYPICAL BIOFUEL FOR AVIATION ALTERNATIVE FUEL PURPOSES

Currently, along with ground used biofuel such as biodiesel, bioethanol has been utilizing widely over the world, alternative fuel for aviation purpose is increasing the consideration of researchers and governments as well as aviation industries. Several key priorities have been targeted for development aviation biofuel and three most important objectives have been identified which are decreasing fossil fuel reserves so that avoiding fluctuation of petroleum costs and reducing Greenhouse Gas (GHG) emissions. This paper presents a short review of researching activities in the field of aviation alternative fuel. Fatty Acid Esters (biodiesel or FAE), Fischer-Tropsch Synthetic Paraffinic Kerosene (FT-SPK) and Bio-derived Synthetic Paraffinic Kerosene (Bio-SPK) are the typical fuels. Research on physicochemical properties, ground engine test and flight demonstration were done by many authors as the investigation of using these biofuels for aviation. Research and development the biofuel for aviation promises a prospect and interesting work, however it also issues many challenges due to strict requirements of aviation fuel.

An Experimental Comparison of the Emissions Characteristics of Standard Jet A-1 and Synthetic Fuels

Emissions characteristics of lean, turbulent, partially premixed swirled flames of synthetic fuels along with a standard Jet A-1 fuel are studied. The investigated synthetic fuels are (a) Fully synthetic jet fuel (FSJF), (b) Fischer Tropsch synthetic paraffinic kerosene (FT-SPK), (c) FT-SPK+20 % hexanol, and (d) FT-SPK+50 % naphthenic cut. The measurements are performed in a tubular combustor equipped with a burner based on the principle of air-blast atomization. The exhaust gas compositions are measured using a non-dispersive infrared gas analyzer for carbon dioxide (CO2) and carbon monoxide (CO), a flame ionization detector for unburned hydrocarbons (UHC), and a chemical luminescence detector for nitric oxides (NO and NO2). The emissions indices (EI) of CO and NOX of the investigated fuels are calculated using guidelines provided by the Society of Automotive Engineers (SAE). Measurements are performed at several combustor pressure levels, i.e., 0.3, 0.54 and 0.8 MPa, to compare the emissions behavior of the investigated fuels at varied operating conditions. At 0.3 MPa of combustor pressure, the order of fuels with their increasing formation of NOX are FSJF, FT-SPK+20 % hexanol, Jet A-1, FT-SPK+50 % naphthenic cut and neat FT-SPK. Differences in the observed NOX formation behavior of the investigated fuels are attributed to their probable different degrees of mixing with air in the combustor. At 0.8 MPa, no significant differences in their emissions characteristics are observed due to very low absolute values; hence we report that at higher pressure conditions which prevail in the aero-engine combustion systems, the emissions characteristics of tested synthetic fuels are very close to that of standard Jet A-1 fuel.

Experimental investigation and detailed modeling of soot aggregate formation and size distribution in laminar coflow diffusion flames of Jet A-1, a synthetic kerosene, and n-decane

A fully-coupled soot formation model is developed to predict the concentration, size, and aggregate structure of soot particles in the atmospheric pressure laminar coflow diffusion flames of a three-component surrogate for Jet A-1, a three-component surrogate for a Fischer–Tropsch Synthetic Paraffinic Kerosene (SPK), and n-decane. To model the chemical structure of the flames and soot precursor formation, a detailed chemical kinetic mechanism for fuel oxidation, with 2185 species and 8217 reactions, is reduced and combined with a Polycyclic Aromatic Hydrocarbon (PAH) formation and growth scheme. The mechanism is coupled to a highly detailed sectional particle dynamics model that predicts the volume fraction, structure, and size of soot particles by considering PAH-based nucleation, surface growth, PAH surface condensation, aggregation, surface oxidation, fragmentation, thermophoresis, and radiation. The simulation results are validated by comparing against experimental data measured for the flames of pre-vaporized fuels. The objectives of the present effort are to more accurately simulate the physical soot formation processes and to improve the predictions of our previously published jet fuel soot formation models, particularly for the size and aggregate structure of soot particles. To this end, the following improvements are considered: (1) addition of particle coalescence submodels to account for the loss of surface area, reduction of the number of primary particles, and increase of primary particle diameters upon collision, (2) consideration of a larger PAH molecule (benzopyrene instead of pyrene) for nucleation and surface growth to enhance the agreement between the soot model and the measured chemical composition of soot particles, and (3) implementation of a dimerization efficiency in the soot inception submodel to account for the collisions between PAH molecules that do not lead to dimerization. The results of two different particle coalescence submodels show that this process is too slow to account for the growth of primary particles, mainly because of the limited rate of particle collisions. Soot volume fraction predictions on the wings and at lower flame heights are considerably improved by using benzopyrene, due to the different distribution of the soot forming PAH molecule in the flame. The computed number of primary particles per aggregate and the diameters of primary particles agree very well with the experimentally measured values after implementing the dimerization efficiency for PAH collisions, because of the reduced rate of soot inception compared to growth by PAH condensation. Concentrations of major gaseous species and flame temperatures are also well predicted by the model. The underprediction of soot concentration on the flame centerline, observed in previous studies, still exists despite minor improvements.

An experimental and modeling study of burning velocities of possible future synthetic jet fuels

Recently, the development of viable alternative aviation fuels has attracted much interest, for several reasons, with reduction of greenhouse gas (GHG) emissions and ensuring security of supply at affordable prices among them. In the present work, several alternative aviation fuels - existing and potential - are investigated by focusing on their heat release: Gas-to-Liquid (GtL: representing a Fischer-Tropsch Synthetic Paraffinic Kerosene (FT-SPK)), a fully synthetic jet fuel (FSJF: Coal-to-Liquid (CtL)), and blends of GtL with 20% 1-hexanol or 50% naphthenic cut, respectively.Burning velocities are measured at ambient pressures and at elevated preheat temperatures exploiting the cone-angle method; equivalence ratios are between about ϕ = 1.0 and ϕ = 1.4. The measured data are used for the validation of a detailed chemical reaction model consisting of 4642 reactions involving 1075 species developed by Dagaut et al. [22,23] following the concept of a surrogate. The comparison between measured burning velocities and predicted laminar flame speeds shows reasonably good agreement with the model for the range of conditions considered in this study. The main features of the reaction model are also discussed, using sensitivity and rate of production analysis. Finally, the experimental data are compared with results obtained earlier for crude-oil kerosene. The findings support the potential of the investigated fuel mixtures to serve as alternative aviation fuels.

An Experimental Comparison of the Sooting Behavior of Synthetic Jet Fuels

An experimental study is conducted for the laminar, atmospheric pressure, sooting, coflow diffusion flames of prevaporized Jet A-1 and four synthetic jet fuels to compare their sooting characteristics and flame structures. Soot volume fraction, species concentration, and temperature profiles are measured, using the laser extinction measurement method, gas chromatography, and fine wire thermocouples, respectively. To evaluate the sooting tendency of the fuels, their smoke point heights are measured using the ASTM D1322 method and compared. The synthetic jet fuels under investigation are (1) Fully Synthetic Jet Fuel (FSJF), which is a coal-to-liquids (CtL) kerosene plus some coal tar derived material from Sasol, (2) Fischer–Tropsch Synthetic Paraffinic Kerosene (FT-SPK), which is a gas-to-liquids (GtL) product from Shell, (3) SPK plus naphthenic cut (50% by volume), and (4) SPK plus hexanol (20% by volume). The threshold sooting index (TSI) of the proposed surrogate mixtures for the fuels are calculated and...

Emissions Characteristics of Military Helicopter Engines with JP-8 and Fischer-Tropsch Fuels

The rapid growth in aviation activities and more stringent U.S. Environmental Protection Agency regulations have increased concerns regarding aircraft emissions, due to their harmful health and environmental impacts, especially in the vicinity of airports and military bases. In this study, the gaseous and particulate-matter emissions of two General Electric T701C engines and one T700 engine were evaluated. The T700 series engines power the U.S. Army's Black Hawk and Apache helicopters. The engines were fueled with standard military JP-8 fuel and were tested at three power settings. In addition, one of the T701C engines was operated on a natural-gas-derived Fischer-Tropsch synthetic paraffinic kerosene jet fuel. Test results show that the T701C engine emits significantly lower particulate-matter emissions than the T700 for all conditions tested. Particulate-matter mass emission indices ranged from 0.2-1.4 g/kg fuel for the T700 and 0.2-0.6 g/kg fuel for the T701C. Slightly higher NOx and lower CO emissions were observed for the T701C compared with the T700. Operation of the T701C with the Fischer-Tropsch fuel rendered dramatic reductions in soot emissions relative to operation on JP-8, due primarily to the lack of aromatic compounds in the alternative fuel. The Fischer-Tropsch fuel also produced smaller particles and slight reductions inmore » CO emissions.« less