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.

Hydrocarbon Fractions from Thermolysis of Waste Plastics as Components of Engine Fuels

Plastics are one of the basic construction materials with a wide range of various applications. One of their disadvantages is the problem of managing the waste they generate. Chemical recycling offers the possibility of liquefying polymeric waste and using it as fuel components. Existing technologies giving good quality products are expensive. The HT technology developed and described by the authors is cheaper and enables a high quality product to be obtained. The authors have shown that the quality of the received fuel components is influenced not only by the polymer waste processing technology, but also by the feedstock composition. The presented thermolysis technology not only enables more advanced recycling, but also gives the possibility of partial improvement of the product quality. A product with the best physico-chemical properties was obtained from a blend of PE:PP:PS used in the ratio 60:30:10. It was proved that diesel and petrol blends composed of a 5% v/v share of petrol and diesel fractions, obtained from thermolysis of plastics, meet the normative requirements of fuel quality standards.

Research of the Influence of Marine Residual Fuel Composition on Sedimentation Due to Incompatibility

The article shows studies of the problem of active sediment formation during mixing of residual fuels, caused by the manifestation of incompatibility. To preserve the quality and reduce sediment formation during transshipment, storage, and transportation of marine residual fuels, a laboratory method for determining the compatibility and stability of fuels has been developed, which makes it possible to determine the quantitative characteristics of the sediment formation activity. According to the method developed, laboratory studies have been carried out to determine incompatible fuel components and the influence of composition on the sedimentation process. Tests were carried out to determine the quality indicators and the individual group composition of the fuel samples. Based on the results of the studies, the dependences of the influence of normal structure paraffins in the range from 55 to 70 wt. % and asphaltenes in the range from 0.5 to 3.5 wt. % in the fuel composition on the sedimentation activity due to incompatibility were obtained. To obtain a convenient tool that is applicable in practice, a nomogram has been developed on the basis of the dependences obtained experimentally. It was also determined that, after reaching the maximum values of sediment formation with a further increase in the content of n-paraffins, saturation is observed, and the value of the sediment content remains at the same level. Maximum total sediment values have been found to depend on asphaltene content and do not significantly exceed them within 10%. The results of the research presented in this article allow laboratory and calculation to determine the possibility of incompatibility and to preserve the quality of marine residual fuels.

Modelling the Process of Production of Diesel Fuels by the Use of Generalized Nets

The process of commodity diesel fuel production in a refinery has been modelled by the use of the Generalized Net (GN) apparatus. GNs are extensions of Petri nets and of all their modifications and extensions. The model accounts for the orders of different grades of diesel fuel and the available amounts of the different diesel fuel components. It can be used for the synchronization and optimization of these processes.

TiO2-Supported Pd as an Efficient and Stable Catalyst for the Mild Hydrotreatment of Tar-Type Compounds

The mild hydrotreatment of a model mixture of tar-type compounds (i.e., naphthalene, 1-methylnaphthalene, acenaphthylene, and phenanthrene) to produce partially hydrogenated products in the range of C9–C15 was studied over Pd supported on TiO2 possessing different crystalline phases. Pd-based catalysts were prepared and characterized by ICP analysis, XRD, N2 adsorption isotherms, HR-TEM, and NH3-TPD, among others. The hydrotreatment activity and selectivity towards the desired hydrogenated products (i.e., tetralin and others) increased with both the acidity and surface area of the catalyst, along with the presence of small and well distributed Pd nanoparticles. For the selected 1.3 wt% Pd/TiO2 nano catalyst, the operational conditions for maximizing tar conversion were found to be 275 °C, 30 bar of H2, and 0.2 g of catalyst for 7 h. The catalyst revealed remarkable hydrotreatment activity and stability after several reuses with practically no changes in TiO2 structure, quite low carbon deposition, and any Pd leaching detected, thus maintaining both a small Pd particle size and adequate distribution, even after regeneration of the catalyst. Additionally, the Pd/TiO2 nano catalyst was demonstrated to be more active than other commonly used metal/alumina and more selective than metal/USY zeolites in the mild hydrotreatment of tar-type compounds, thus providing an efficient catalytic route for obtaining partially hydrogenated C9–C15 hydrocarbons useful as jet-fuel components or additives (improvers), as well as chemicals and solvents for industrial applications.