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Kerosene from the hydrocracking is commonly used to produce JET fuel. Depending on the deactivation of the catalyst, the aromatic content of such kerosene increases to a level where it can no longer be used for JET fuel production. The objective of this study was to determine whether the aromatic content of kerosene from hydrocracking can be reduced under the conditions used for hydrotreating straight-run middle distillates. The kerosene obtained from a real hydrocracker unit was investigated in a laboratory fixed-bed unit packed with a Ni-Mo/Al2O3 catalyst. Aromatics content was analyzed utilizing ASTM D6379 (HPLC). As a result of the hydrogenation, the aromatic content was reduced from 22.6 to 14.5 wt.% (3 MPa) and 3.0 wt.% (6 MPa). The product contained 60–70 wt.% cycloalkanes. The smoke point was improved by 3.3 mm (3 MPa) up to 9.7 mm (6 MPa), and the cetane index by 1.1 or 3.9 units, respectively. The (H/C)at ratio in kerosene increased from 1.89 to 1.98. Furthermore, no significant cracking occurred during the hydrogenation. Overall, we demonstrate that the aromatic content of such kerosene can be very well controlled by downstream hydrogenation under conditions common in oil refineries for the desulfurization of middle distillates. [ABSTRACT FROM AUTHOR]

• Jet fuel is the fastest-growing oil-based commodity. • Hydrotreated esters and fatty acids (HEFA), kerosene from hydrocracking (Jet HC) and FCC heavy naphtha (FCC HN) were researched. • The blendability of HEFA with Jet HC and with FCC HN was determined to meet the specification of JET A-1. • The results can help increase the production of jet fuel in oil refineries. Jet fuel is the fastest-growing oil-based commodity. As it is difficult to substitute it with other energies, more attention is being paid to sustainable aviation fuels (SAFs). Hydrogenated esters and fatty acids (HEFAs) dominate SAF now. The jet fuel consumption forecasts show that the share of petroleum hydrocarbons in jet fuel will remain high until 2050. As oil consumption will decline with electromobility, the availability of straight-run kerosene for jet fuel will also decline. For this reason, the utilization of alternative petroleum fractions, such as hydrocracking kerosene (Jet HC) or hydrotreated heavy FCC naphtha (FCC HN), and their miscibility with HEFA have been studied. These components were generally blendable with HEFA. All properties were linearly dependent on the HEFA content, with the exception of the smoke point. Taking into account the Jet A-1 requirements, only Jet HC met them completely. Since the components have opposing properties, blending them has opened an application window in jet fuel, wider for blends of HEFA with Jet HC (0–68 vol% HEFA) and narrower for HEFA with FCC HN (73–81 vol% HEFA). The limitations were the low density of HEFA and the high density, the high aromatic content, the low smoke point, and the low net calorific value of FCC HN. To expand the application window of FCC HN in jet fuel, further research will focus on the hydrogenation of aromatics. [ABSTRACT FROM AUTHOR]

Presents information on dieletric resonators, which were prepared and tested for a two pole filter. Other information on the resonators; Information on the YBa...Cu...O...films.

We prepared and tested dielectric resonators designed for a two pole filter. These resonators were LaAlO/sub 3/ single crystalline cylinders which were covered on the end faces by about 350 nm YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// thin films and on the cylindrical surface by 4 /spl mu/m gold films. The YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// films were c-axis oriented with mosaic spreads of about 0.3/spl deg/. The inductive transition temperatures were above 90 K. The HF properties were characterized by evaluation of the H/sub 011/ mode at 8.05 GHz, and by measuring the surface resistance at 18.9 GHz. At 77 K the Q-value of this resonance was typically 12000, which is about a factor of 2 higher than the Q-value of 6560 found for end faces covered with pure copper. From these resonators two-pole bandpass filters were constructed that at 77 K showed an insertion loss of -0.26 dB at their center frequency of 6.3 GHz. [ABSTRACT FROM PUBLISHER]