Scenarios Analysis For Penetration of XTL Fuels

This paper presents California Energy Commission (Energy Commission) staff’s analysis of the value of future development of three synthetic diesel fuel blends as replacements for and supplements to conventional petroleum-based diesel for California’s transportation fuels market to the year 2050. Collectively referred to as XTLs, the blends include gas-to-liquid (GTL), coal-to-liquid (CTL), and petroleum coke-to-liquid (PTL). This paper employs the AB 1007 Full-Fuel Cycle Analysis results and quantifies the emissions implications with the various XTL scenarios evaluated. Staff analyzed the effects of monetary and non-monetary incentives and mandates, their cost-effectiveness in obtaining petroleum and emissions reductions, and the sufficiency of consumer demand and expected XTL supply. Based on numerous findings, staff concluded that XTL fuels have the potential to significantly displace petroleum demand and to reduce emissions and, thus, are worthy of further exploration. Staff generated price supply curves for scenarios where XTLs were mandated or incentivized to displace 10 to 40 percent of diesel demand by 2030 – 2050. Key Words: XTL, XTLs, GTL, CTL, PTL, gas-to-liquid, coal-to-liquid, petroleum coke-to-liquid, diesel fuel blends, synthetic diesel fuels, synthetic diesel blends.

Comparison of Ignition Delays and Liquid Penetrations of JP-8, Synthetic JP-8, and a JP-8 Surrogate under Diesel Engine Conditions

The U.S. Army and many NATO affiliates have adopted a ‘one fuel forward fuel policy’ (OFF). The goal of the OFF policy is reducing the logistics and cost involved with providing fuel for military vehicles. With this policy, the logical choice fuel is military grade jet petroleum, JP-8, because of the fuel constraints of turbo-jet engines. This requirement has made it necessary to run military compression ignited engines on JP-8. To reduce the Army’s reliance on petroleum based fuels an alternative fuel, synthetic JP-8, derived from coal and made in the Fischer-Tropsch production method is allowed to be blended up to 50% with JP-8. The two fuels have varying cetane numbers of for 43.1 for JP-8 and 25 for the synthetic JP-8 which influence combustion characteristics. Therefore, the goal of the current work is to characterize the ignition characteristics of synthetic JP-8 as compared to the reference JP-8 under the same test conditions. A JP-8 surrogate fuel is also developed and compared against the baseline fuel in terms of both ignition behavior and liquid penetration. Testing is conducted in an optically accessible combustion vessel sweeping ambient temperatures and densities of 800 – 1100 K and 7.3 – 30.2 kg/m3, respectively. The resultant data is used in comparison of all three fuels in ignition delay and steady state liquid penetration characteristics. Correlations are also developed for calculating the ignition delay of both the JP-8 and the synthetic JP-8 fuel and is used to compare to the surrogate fuel and to compare to a pool of data from past work on JP-8. Results of these comparisons show a 50% increase in the ignition delay and a 10% shorter steady state liquid penetration of the low cetane value synthetic JP-8 over the baseline JP-8 fuel sample. Findings also show the surrogate matches the baseline fuel to within 10% for ignition delays but it over penetrates the baseline fuel by around 30% for liquid penetration

Theoretical investigaion of the performance of alternative aviation fuels in an aero-enginve combustion chamber

When considering alternative fuels for aviation, factors such as the overall efficiency of the combustion process and the levels of emissions emitted to the atmosphere, need to be critically evaluated. The physical and chemical properties of a fuel influence the combustion efficiency and emissions and therefore need to be considered. The energy content of a biofuel, which is influenced negatively by the presence of oxygen in the molecular structure (i.e. oxygenated chemical compounds), is relatively low when compared with that of conventional jet fuel. This means that the overall efficiency of the process will be different. In this paper two possible scenarios have been investigated in order to assess the potential to directly replace conventional jet fuel with Methyl Buthanoate - MB (a short chain FAME representing biofuel) and a synthetic jet fuel (FT fuel) using Computational Fluid Dynamics (CFD) modelling in a typical Modern Air-Spray Combustor (MAC). In addition the impact of fuel blending on the combustion performance has been investigated. Computational Fluid Dynamics (CFD) has been verified and validated over past decades to be a powerful design tool in industries where experimental work can be costly, hazardous and time consuming, to support the design and development process. With recent developments in processor speeds and solver improvements, CFD has been successfully validated and used as a tool for optimizing combustor technology. Combustion of each fuel is calculated using a mixture fraction/pdf approach and the turbulence-chemistry interaction has been modelled using the Laminar Flamelet approach. Detailed chemical reaction mechanisms, developed and validated recently by the authors for aviation fuel including kerosene, synthetic fuel and bio-aviation fuel have been employed in the CFD modelling. A detailed comparison of kerosene with alternative fuel performance has been made.

Experimental and Modeling Study of the Oxidation of Synthetic Jet Fuels

International audienceStudies on combustion of synthetic jet fuels is of growing importance because of their potential for addressing security of supply and air transportation sustainability. The oxidation of a 100% naphthenic cut (NC) that fits with typical chemical composition of biomass or coal liquefaction products, gas-to-liquid fuel (GtL), and a GtL-NC mixture were studied in a jet-stirred reactor under the same conditions (550-1150 K; 10 bar; equivalence ratio of 0.5, 1, and 2; initial fuel concentration of 1000 ppm). Surrogate model-fuels were designed based on fuel composition and chemical properties for simulating the kinetics of oxidation of these fuels. We used model-fuels consisting of mixtures of n-decane, decalin, tetralin, 2-methylheptane, 3-methylheptane, n-propyl cyclohexane, and n-propylbenzene. The proposed detailed chemical kinetic reaction mechanism was validated using the full experimental database obtained for the oxidation of pure GtL, GtL-NC mixture, and pure NC. Kinetic reaction pathway analyses and sensitivity analyses were used for interpreting the results

Comparative analysis of alternative fuels in detonation combustion

Detonation combustion prominently exhibits high thermodynamic efficiency which leads to better performance. As compared to the conventionally used isobaric heat addition in a Brayton cycle combustor, detonation uses a novel isochoric Humphrey cycle which utilises shocks and detonation waves to provide pressure-rise combustion. Such unsteady combustion has already been explored in wave rotor, pulse detonation engine and rotating detonation engine configurations as alternative technologies for the next generation of the aerospace propulsion systems. However, in addition to the better performance that the detonation mode of combustion offers, it is crucial to observe the environmental concerns as well. Therefore, this paper presents a one-dimensional numerical analysis for alternative fuels: Jet-A, Acetylene, Jatropha Bio-synthetic Paraffinic Kerosene, Camelina Bio-synthetic Paraffinic Kerosene, Algae Biofuel, and Microalgae Biofuel under detonation combustion conditions. For simplicity, the analysis is modelled using an open tube geometry. The analysis employs the Rankine-Hugoniot Equation, Rayleigh Line Equation, and Zel’dovich–von Neumann–Doering model and takes into account species mole, mass fraction, and enthalpies-of-formation of the reactants. Initially, minimum conditions for the detonation of each fuel are determined. Pressure, temperature, and density ratios at each stage of the combustion tube for different types of fuel are then explored systematically. Finally, the influence of different initial conditions is numerically examined to make a comparison for these fuels

Effects of biofuels properties on aircraft engine performance

Purpose-The purpose of this paper is to examine the effects of heat capacity and density of biofuels on aircraft engine performance indicated by thrust and fuel consumption. Design/methodology/approach-The influence of heat capacity and density was examined by simulating biofuels in a two-spool high-bypass turbofan engine running at cruise condition using a Cranfield in-house engine performance computer tool (PYTHIA). The effect of heat capacity and density on engine performance was evaluated through a comparison between kerosene and biofuels. Two types of biofuels were considered: Jatropha Bio-synthetic Paraffinic Kerosene (JSPK) and Camelina Bio-synthetic Paraffinic Kerosene (CSPK). Findings-Results show an increase in engine thrust and a reduction in fuel consumption as the percentage of biofuel in the kerosene/biofuel mixture increases. Besides a low heating value, an effect of heat capacity on increasing engine thrust and an effect of density on reducing engine fuel consumption are observed. Practical implications-The utilisation of biofuel in aircraft engines may result in reducing over-dependency on crude oil. Originality/value-This paper observes secondary factors (heat capacity and density) that may influence aircraft engine performance which should be taken into consideration when selecting new fuel for new engine designs

Temporal Control over Transient Chemical Systems using Structurally Diverse Chemical Fuels

The next generation of adaptive, intelligent chemical systems will rely on a continuous supply of energy to maintain the functional state. Such systems will require chemical methodology that provides precise control over the energy dissipation process, and thus, the lifetime of the transiently activated function. This manuscript reports on the use of structurally diverse chemical fuels to control the lifetime of two different systems under dissipative conditions: transient signal generation and the transient formation of self-assembled aggregates. The energy stored in the fuels is dissipated at different rates by an enzyme, which in-stalls a dependence of the lifetime of the active system on the chemical structure of the fuel. In the case of transient signal generation, it is shown that different chemical fuels can be used to generate a vast range of signal profiles, allowing temporal control over two orders of magnitude. Regarding self-assembly under dissipative conditions, the ability to control the lifetime using different fuels turns out to be particularly important as stable aggregates are formed only at well-defined surfactant/fuel ratios, meaning that temporal control cannot be achieved by simply changing the fuel concentration

Fuels for Future Electric Power

OVER THE NEXT FORTY YEARS, THE U.S. WILL EXPERIENCE PROBLEMS BECAUSE OF DWINDLING SUPPLIES OF FOSSIL FUELS AND AN INCREASING DEPENDENCE ON FOREIGN OIL. SEVERAL ALTERNATIVES ARE AVAILABLE, SUCH AS MORE STRINGENT CONSERVATION MEASURES OR ALTERNATIVE SOURCES OF ENERGY. HOWEVER, NO SINGLE ALTERNATIVE WILL BE SUFFICIENT. A STUDY WAS CONDUCTED TO DETERMINE THE MOST EFFICIENT ALLOCATION POSSIBLE OF RESOURCES. THE ANALYSIS WAS CONDUCTED ON THE BASIS OF ASSUMED HAPPENINGS IN THE FUTURE RATHER THAN BY PROJECTING HISTORIC TRENDS INTO THE FUTURE. FOR EXAMPLE, AS ONE SOURCE OF ENERGY SUCH AS OIL BECOMES MORE SCARCE, THE COST WILL GO UP, INDUCING A CHANGE TO ANOTHER SOURCE. SYNTHETIC FUELS FROM COAL AND HYDROGEN FROM ELECTROLYSIS WILL BECOME MORE PRACTICAL BY THE END OF THE CENTURY. COAL AND OIL WILL BE USED. HEAVILY THIS CENTURY WITH NUCLEAR FUEL BECOMING MORE EFFICIENT EARLY IN THE NEXT CENTURY. CHART

Synthetic fuel production from shredded scrap waste

This technological innovation project involved material identification, and design, installation, implementation, and evaluation of a pilot plant with capacity of 10 t per batch to recover materials and produce synthetic fuels (oil, syngas and solid) from shredded scrap waste. The results showed the proper way to separate materials (metals, and organic and inert compounds), and to perform the pyrolysis process to produce gas, oil, and coke as synthetic fuels from organic waste. The process started with the physicochemical characterization of the waste, followed by the selection of separation, sorting and processing technologies, and the definition of pyrolysis process parameters. Finally, the synthetic fuels were characterized, and uses for the furnace billet, ladle preheating, internal combustion engines, and auto generation were suggested. The results showed 82 % recovery of magnetic and non-magnetic metals, and production of synthetic fuels with PCI between 20 650 and 36 900 kJ/kg

Poland’s Energy Security in Light of a Statistical Analysis

In the research on Poland’s energy security compared to the European Union, data clustering was carried out according to the following methods: the Ward method, the full bond (furthest neighbourhood) method, analysis using the k-means method, and multidimensional scaling. In order to define the shifts in the direction of Poland’s energy security, synthetic indices for 2000 and 2008 have been calculated. Obtaining the answers to the above questions allowed for defining the main trends in Poland’s activities aimed at increasing its energy security.W badaniach nad bezpieczeństwem energetycznym Polski na tle Unii Europejskiej została zastosowana analiza skupień przeprowadzona metodą Warda i metodą pełnego wiązania (najdalszego sąsiedztwa) oraz analiza metodą k-średnich i skalowanie wielowymiarowe. W celu uchwycenia kierunków zmian bezpieczeństwa energetycznego Polski zostały obliczone wskaźniki syntetyczne dla 2000 r. i 2008 r. Uzyskanie odpowiedzi na powyższe pytania pozwoliło określić główne kierunki działania Polski na rzecz zwiększenia bezpieczeństwa energetycznego kraju