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The importance of tanks for storing cryogenic fluids in the energy industry is increasing because of ongoing political conflicts and the implementation of more environmentally friendly energy sources. Key representatives for the application of cryogenic tanks are natural gas in the form of Liquefied Natural Gas (LNG) and hydrogen, e. g. in the form of Liquefied Hydrogen (LH2), for which significantly higher transport capacities can be achieved with the same transport volume using cryogenic storages than with storages based solely on overpressure.
What applies to all cryogenic transported fluids in common is their condition that must be maintained. Hence heat flows into the preserved fluid must be minimized. Thermal super Insulations (TSI) based on e. g. multilayer insulations (MLI), perlites, and vacuum are utilized for this purpose and have already proven themselves in similar applications. However, for the use of tanks for cryogenic fluids in the transport sector, there is insufficient knowledge regarding the course and consequences of incidents, which is due to the still short period of use and the few documented incidents, hence few investigations carried out in this field. Typical scenarios in the transport sector represent car accidents with collisions, fires, and their combination, which are associated with extraordinary loads on the tank.
The focus of this study is to investigate the behavior of TSI as a result of their thermal exposure to a heat source representing a fire. It is worth mentioning that this could lead to an increase of the heat flux into a tank by several orders of magnitude, and to permanent damage of the TSI, ultimately rapid release of flammable gas as well as a Boiling Liquide Expanding Vapour Explosion (BLEVE). For this purpose, a high temperature thermal vacuum chamber (HTTVC) has been developed that allows thermal loading of MLI or perlites in a vacuum and simultaneous measurement of heat flow through this TSI. The HTTVC is designed to represent realistic insulation conditions and to withstand thermal loads from typical design fires.
The HTTVC was applied to investigate TSI based on MLI and vacuum. It is shown that the thermal stress caused permanent damage to the TSI, with shrinkage, phase change, pyrolysis, and condensation being significant damage mechanisms. The results are relevant for the evaluation of accident scenarios and can thus contribute to the improvement of TSI and the development of emergency measures for the protection of persons and infrastructures.
Liquid cargo has a significant impact on the interface wheel-track interaction. The sloshing affects the track-railcar's dynamic behavior. The effect is detectable at the track level and at the vehicle. Its characterization requires the combination of different techniques:
Empirical Mode Decomposition (EMD)
Time-Frequency Maps
Sloshing occurred when significant perturbations happened in the railcar:
The railcar entered a curve
Reduction in its travel speed
A railcar with a tank is a clear example of a multibody dynamic system with a nonlinear behavior.
100 mm of PUR-foam give satisfying results in terms of
thermal properties. The non-pressure testing methods gives reliable and repeatable results. Bending modulus of laminates does not change until the first damage occurs. After that, the bending modulus decreases by 50 % but max. stress is still higher than at room temperature.
Avoiding road crashes has been the purpose behind many specialized software and hardware systems, involving both active and passive safety principles. Global Positioning technologies were incorporated into the transportation systems with the main purpose of acquiring the position of the vehicle under a continuous basis, for security and economy purposes. However, the GPS data can also be used for assessing the level of safety at which the vehicle is driven. On the basis of the essential data available from commercial GPS devices, in this paper we propose a combined performance measurement to assess the road safety level at which the vehicle is being driven. Such performance measure uses GPS data of the vehicle displacement, including the speed and the acceleration, as well as the course (latitude and longitude coordinates), in an integral driving assessment formulation that can run in real time. Results from the experimental use of this formulation suggest that the level of safety in the driving is time dependent, and that there are risky situations when different factors converge.
Tanks with capacity larger than 700 m3, could be exposed to a resonance excitation when subjected to earthquake motions, regardless of the fill level. Further studies to assess the dynamic forces linked to such resonance and close-to-resonance situations, in a context of a standard overloading situation due to sloshing forces.
Transport safety depends in great extent of what happens to the cargo once the carrying vehicle derails or rollovers. The exposure of tanks to direct fire is a condition that potentially involves catastrophic consequences. Studying the behavior of the contained fluid under these drastic circumstances, is critical to develop methods and techniques to mitigate the serious consequences of many mishaps. In this paper, the experimental potentials of a Particle Image Velocimetry data acquisition system are described, for providing experimental data that could be used to calibrate mathematical models. As an example of the situations that need to be modelled, an experiment is described concerning the effect of the boundary conditions and protecting devices, on the rate of variation of pressure and temperature of the fluid in a tank exposed to a direct fire. In this regard, the results emphasize the importance of equipping the vessels with both thermal insulation and safety valves.
There was a need to validate the longitudinal performance required for the cargo securement, as current standards exhibit differences.
A model has been proposed in this paper, to simulate the effect of a shifting cargo on the braking efficiency of the vehicle. Results suggest that the braking efficiency can be greater in the case of a shifting cargo, as a result of the uncoupling of the cargo-vehicle systems, implying that similar braking forces are exerted on a reduced mass. The shifting of the cargo can occur as a result of the vibration of the vehicle, that leads to having a diminished friction force to prevent the shifting of the cargo.
Small and large-scale tests have been carried out Pressure vessel – to improve numerical modelling Different types of fire must be distinguished Modelling of vessels were discussed Test configuration has been developed to see what happens in the vessel First results encourage us to continue the Research Thermohydraulics needs further work (boundary layers).
Wasserdruckprüfung kann entfallen: Schutzziel definieren, Qualitätssichernde Maßnahmen während der Herstellung, Nachweise der vorhandenen Qualität muss stetig erfolgen mittels: Betriebsüberwachung, zfP Bewertung des Standes der Technik: Zustandsorientierte Instandhaltung/Inspektion, Reduzierung von Ausfallzeiten durch optimierten Betrieb