Sooting tendencies of diesel fuel component mixtures follow a linear mixing rule

With the growing importance of climate change, soot emissions from engines have been receiving increasing attention since black carbon is the second largest source of global warming. A sooting tendency can be used to quantify the extent of soot formation in a combustion device for a given fuel molecule, and therefore to quantify the soot reduction benefits of alternative fuels. However real fuels are complex mixtures of multiple components. In this work, we have used experimental methods to investigate how the sooting tendency of a blended fuel mixture is related to the sooting tendencies of the individual components. A test matrix was formulated that includes sixteen mixtures of six components that are representative of the main categories of hydrocarbons in diesel (eicosane (ECO) for alkanes, isocetane (ICE) for isoalkanes, butylcyclohexane (BCH) for cycloalkanes, 1-methylnaphthalene (1MN) for aromatics, tetralin for naphthoaromatics, and methyl-decanoate (MDC) for oxygenates). Most of the mixtures contain three to five components. The sooting tendency of each mixture was characterized by yield sooting index (YSI), which is based on the soot yield when a methane/air nonpremixed flame is doped with 1000 ppm of the test fuel. The YSIs were measured experimentally. The results show that the blending behavior is linear, i.e., the YSI of the mixtures is the mole-fraction-weighted average of the component YSIs. Experimental results have shown that the sooting tendency of a fuel mixture can be accurately estimated as the linear combination of the individual components. In addition, mass density of the mixtures is also measured, and a linear blending rule is applied to test whether mixing rules exist for mass density of diesel mixtures in this study. Results also have shown that the mixing rule tested in this study is valid and mass density of a mixture can be accurately estimated from the linear combination of the individual components.

Future-Oriented Experimental Characterization of 3D Printed and Conventional Elastomers Based on Their Swelling Behavior

The present study investigates different elastomers with regard to their behavior towards liquids such as moisture, fuels, or fuel components. First, four additively manufactured materials are examined in detail with respect to their swelling in the fuel component toluene as well as in water. The chemical nature of the materials is elucidated by means of infrared spectroscopy. The experimentally derived absorption curves of the materials in the liquids are described mathematically using Fick’s diffusion law. The mechanical behavior is determined by uniaxial tensile tests, which are evaluated on the basis of stress and strain at break. The results of the study allow for deriving valuable recommendations regarding the printing process and postprocessing. Second, this article investigates the swelling behavior of new as well as thermo-oxidatively aged elastomers in synthetic fuels. For this purpose, an analysis routine is presented using sorption experiments combined with gas chromatography and mass spectrometry and is thus capable of analyzing the swelling behavior multifacetted. The transition of elastomer constituents into the surrounding fuel at different aging and sorption times is determined precisely. The change in mechanical properties is quantified using density measurements, micro Shore A hardness measurements, and the parameters stress and strain at break from uniaxial tensile tests.

Use of a “green” propellant in low-thrust control jet engine systems

The aim of this work is to analyze the state of the art in the development and use of pollution-free (“green”) propellants in low-thrust jet engines used as actuators of spacecraft stabilization and flight control systems and to adapt computational methods to the determination of “green”-propellant engine thrust characteristics. The monopropellant that is now widely used in the above-mentioned engines is hydrazine, whose decomposition produces a jet thrust due to the gaseous reaction products flowing out of a supersonic nozzle. Because of the high toxicity of hydrazine and the complex technology of hydrazine filling, it is important to search for its less toxic substitutes that would compare well with it in energy and mass characteristics. A promising line of this substitution is the use of ion liquids classed with “green” ones. The main components of these propellants are a water solution of an ion liquid and a fuel component. The exothermic thermocatalytic decomposition of a “green” propellant is combined with the combustion of its fuel component and increases the combustion chamber pressure due to the formation of gaseous products, which produces an engine thrust. It is well known that a “green” propellant itself and the products of its decomposition and combustion are far less toxic that hydrazine and the products of its decomposition, The paper presents data on foreign developments of “green” propellants of different types, which are under test in ground (bench) conditions and on a number of spacecraft. The key parameter that governs the efficiency of the jet propulsion system thrust characteristics is the performance of the decomposition and combustion products, which depends on their temperature and chemical composition. The use of equilibrium high-temperature process calculation methods for this purpose is too idealized and calls for experimental verification. Besides, a substantial contribution to the end effect is made by the design features of propellant feed and flow through a fine-dispersed catalyst layer aimed at maximizing the monopropellant-catalyst contact area. As a result, in addition to the computational determination of the thrust characteristics of a propulsion system under design, its experimental tryout is mandatory. The literature gives information on the performance data of “green”-propellant propulsion systems for single engines. However, in spacecraft control engine systems their number may amount to 8–16; in addition, they operate in different regimes and may differ in thrust/throttling characteristics, which leads to unstable propellant feed to operating engines. To predict these processes, the paper suggests a mathematical model developed at the Institute of Technical Mechanics of the National Academy of Sciences of Ukraine and the State Space Agency of Ukraine and adapted to “green”-propellant engine systems. The model serves to calculate the operation of low-thrust jet engine systems and describes the propellant flow in propellant feed lines, propellant valves, and combustion chambers. To implement the model, use was made of the results of experimental studies on a prototype “green”-propellant engine developed at Yuzhnoye State Design Office. The analysis of the experimental results made it possible to refine the performance parameters of the monopropellant employed and obtain computational data that may be used in analyzing the operation of a single engine or an engine system on this propellant type in ground and flight conditions

Hydro-liquefaction of asphaltene catalyzed by molybdenum-nickel bimetallic catalysts in slurry bed

The aim of this study is to achieve the hydro-liquefaction of asphaltene for the production of liquid fuel. The oil soluble molybdenum catalysts, molybdenum dialkyl dithiophosphate, and nickel carboxylate precursor with different carbon chains, were synthesized. The catalysts were characterized by ICP-OES, TEM and XPS. Their catalytic performance for the hydro-liquefaction of asphaltene to liquid fuels was investigated in a slurry bed reactor by using decalin as hydrogen donor and dispersant. The results show that the bimetal catalytic system composed of molybdenum dialkyl dithiophosphate and caproic acid nickel produces more MoS2 and NiS x active species. The metal contents of which accounts for 81.8 and 81.0 wt% of the total amount of Mo and Ni, respectively, and thus exhibits the best catalytic performance among the catalysts studied. The liquid yield of the asphaltene hydrogenation over the bimetal catalyst is 84.6 wt%, which is much higher than that over other catalysts, and the coke content is only 8.6 wt% under the conditions of 1000 μg/g of total metal addition, 1:1 Mo/Ni metal mass ratio and 1:1 asphaltene/naphthalene mass ratio. The content of saturated and aromatic components in the liquid products of asphaltene hydrogenation of the bimetal catalyst system is 78.9 wt%, which is a high-quality liquid fuel component.

Obtaining a diesel fuel component from liquid products of oxidative pyrolysis of wood

Recycling and rational use of wood-processing industry waste is an urgent task for the economy and industry. On the basis of experimental studies on the oxidative pyrolysis of Siberian pine and Downy birch, a basic technological scheme for components of motor fuels obtaining is proposed. It is shown that the main components of liquid products of wood pyrolysis in water vapor are aromatic and saturated hydrocarbons, as well as oxygen-containing compounds that need to be hydrogenated.

Preparation and Characterization of Mg Doped ZnAI2O4Spinel Nanoparticles

In the present study, combustion technique is adopted to study the impact of Mg2+ ion doping on ZnAI2O4 nanoparticles (NPs). L-arginine is used as a fuel component. The Mg2+ ions play a pivotal role in persuading various characteristics of ZnAI2O4 NPs. Various characterization technqiues such as Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), energy dispersive X-ray analysis (EDX), high resolution scanning electron microscopy (HR-SEM), diffuse reflectance spectroscopy (DRS), Thermo-gravimetric/differential thermal analysis (TG-DTA) and vibrating sample magnetometer (VSM) were carried out in order to synthesize the nanoparticles. Single phase cubic spinel structure of ZnAl2O4 (gahnite) formation was confirmed from the XRD characterization process of the nanoparticles. Estimated average crystallite size range of 11.85 nm to 19.02 nm was observed from Debye-Scherrer. Spherical morphology with uniform distributions was observed from HR-SEM characterization images. From the band gap studies, the attained band gap values were found to lie within 5.41 eV–4.66 eV range. The ZnAl2O4 and Mg:ZnAl2O4 NPs exhibited super-paramagnetic nature confirmed by magnetic measurements. The obtained results make ZnAl2O 4and Mg:ZnAl2O4 NPs appropriate for various optical, catalytic, energy and data storage applications.

Problems and Possible Options for Improving the Efficiency of Diesel Generation

The potential for improving the energy efficiency of diesel generation really exists and can be estimated in real money. Reducing the fuel component is one of the priority areas. This article discusses the problems and possible options for the modernization and reconstruction of diesel generation, including the positive experience of JSC Sakhaenergo of the Republic of Sakha (Yakutia).

The emission of harmful compounds from the marine diesel engine fueled by a blend of n-butanol and marine fuel

The use of renewable fuels may be an action leading to the reduction of pollutant emissions. This group includes biobutanol as a product of biomass fermentation. Some of its physicochemical properties, including the ability to mix with hydrocarbon fuels, make it suitable for use as a fuel component for marine diesel engines. The article presents the results of research on the concentration of exhaust gas components of a Sulzer 6AL20 / 24 diesel engine powered by a mixture of n-butane and diesel oil. The emission intensity were calculated for the tested components: carbon monoxide, carbon dioxide and nitrogen oxides. The emission intensity surface graphs were created based on the calculated data. The tests were carried out using different concentrations of the mixture of n-butanol and marine fuel.