Microbial problems in connection with storage of jet fuel in rock caverns. Development of a process for purification of corrosive jet fuel). Mikrobiella problem vid bergrumslagring av jetbraensle. Utveckling av process foer rening av korrosivt jetbraensle
The literature concerning desulfurization is summarized. Investigations concerning the use of different compounds in order to purify corrosive jet fuel are described. A process for purification of corrosive jet fuel with 1-5 mg/l elemental sulphur was developed which is based on powdered silver as adsorbent. The capacity for adsorption was determined. On the basis of the data obtained, a scale-up was carried out to a full scale plant. The plant was planned for a capacity of 100 - 300 mT fuel/hour and so that it can be constructed as a mobile unit enabling it to be transported to various storage plants.
Microbial problems in connection with storage of jet fuel in rock caverns. Methods to inhibit development of corrosive fuel. Mikrobiella problem vid bergrumslagring av jetbraensle. Inhiberingsmetoder foer att foerhindra uppkomst av korrosivt braensle
Norqvist, A.; Edlund, A.; Roffey
Problems with long-term storage of jet fuel in rock caverns have during the last years been observed. The problems have mainly been concerned with the accumulation of corrosive compounds in the fuel. Studies in laboratory model systems were carried out in order to understand which factors are important in causing the problems. The rate of groundwater leaking in, the oxygen and sulfate concentration in the bedwater, the amount of sediment, and the temperature were shown to be some of the more-important factors. With the aim to find some suitable methods to prevent the problems from arising, studies in model systems were also carried out. Oxygenation of the bedwater or addition of a biodegradable biocide gave positive effects resulting in reduction of microbial activities and no development of corrosive fuel.
Craig, Peter D.
At 30° latitude, the inertial frequency is equal to the frequency of the diurnal tide, or diurnal winds such as a sea breeze. The extension of Ekman's (1905, Arkiv foer Matematik, Astronomi och Fysik, 2, 11) theory to incorporate oscillatory forcing indicates that at the latitude where the inertial and forcing frequencies are the same, the sense of rotation of the current profile with depth will change. The coastal-ocean model of BATTISTI and CLARKE (1982, Journal of Physical Oceanography, 12, 8-16) is extended to include cross-shore wind stress and a constant eddy viscosity model of vertical current structure. The model is used to demonstrate the latitude-dependence of the tidally and wind-forced current structure near 30° latitude. The results are best interpreted in a fixed reference frame, rather than the rotating f-plane.
A recently discovered superconductor, magnesium diboride (MgB2), can be used to fabricate conducting leads used in cryogenic applications. Dis covered to be superconducting in 2001, MgB2 has the advantage of remaining superconducting at higher temperatures than the previously used material, NbTi. The purpose of these leads is to provide 2 A of electricity to motors located in a 1.3 K environment. The providing environment is a relatively warm 17 K. Requirements for these leads are to survive temperature fluctuations in the 5 K and 11 K heat sinks, and not conduct excessive heat into the 1.3 K environment. Test data showed that each lead in the assembly could conduct 5 A at 4 K, which, when scaled to 17 K, still provided more than the required 2 A. The lead assembly consists of 12 steelclad MgB2 wires, a tensioned Kevlar support, a thermal heat sink interface at 4 K, and base plates. The wires are soldered to heavy copper leads at the 17 K end, and to thin copper-clad NbTi leads at the 1.3 K end. The leads were designed, fabricated, and tested at the Forschungszentrum Karlsruhe - Institut foer Technische Physik before inclusion in Goddard's XRS (X-Ray Spectrometer) instrument onboard the Astro-E2 spacecraft. A key factor is that MgB2 remains superconducting up to 30 K, which means that it does not introduce joule heating as a resistive wire would. Because the required temperature ranges are 1.3-17 K, this provides a large margin of safety. Previous designs lost superconductivity at around 8 K. The disadvantage to MgB2 is that it is a brittle ceramic, and making thin wires from it is challenging. The solution was to encase the leads in thin steel tubes for strength. Previous designs were so brittle as to risk instrument survival. MgB2 leads can be used in any cryogenic application where small currents need to be conducted at below 30 K. Because previous designs would superconduct only at up to 8 K, this new design would be ideal for the 8-30 K range.
Park, J.; Lin, M. C.
The thermal decomposition of ammonium nitrate, NH4NO3 (AN), in the gas phase has been studied at 423-56 K by pyrolysis/mass spectrometry under low-pressure conditions using a Saalfeld reactor coated with boric acid. The sublimation of NH4NO3 at 423 K was proposed to produce equal amounts of NH3 and HNO3, followed by the decomposition reaction of HNO3, HNO3 + M → OH + NO2 + M (where M = third-body and reactor surface). The absolute yields of N2, N2O, H2O, and NH3, which can be unambiguously measured and quantitatively calibrated under a constant pressure at 5-6.2 torr He are kinetically modeled using the detailed [H,N,O]-mechanism established earlier for the simulation of NH3-NO2 (Park, J.; Lin, M. C. Technologies and Combustion for a Clean Environment. Proc. 4th Int. Conf. 1997, 34-1, 1-5) and ADN decomposition reactions (Park, J.; Chakraborty, D.; Lin, M. C. Proc. Combust. Inst. 1998, 27, 2351-2357). Since the homogeneous decomposition reaction of HNO3 itself was found to be too slow to account for the consumption of reactants and the formation of products, we also introduced the heterogeneous decomposition of HNO3 in our kinetic modeling. The heterogeneous decomposition rate of HNO3, HNO3 + (B2O3/SiO2) → OH + NO2 + (B2O3/SiO2), was determined by varying its rate to match the modeled result to the measured concentrations of NH3 and H2O; the rate could be represented by k2b = 7.91 × 107 exp(-12 600/T) s-1, which appears to be consistent with those reported by Johnston and co-workers (Johnston, H. S.; Foering, L.; Tao, Y.-S.; Messerly, G. H. J. Am. Chem. Soc. 1951, 73, 2319-2321) for HNO3 decomposition on glass reactors at higher temperatures. Notably, the concentration profiles of all species measured could be satisfactorily predicted by the existing [H,N,O]-mechanism with the heterogeneous initiation process.