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In this presentation safety aspects of hydrogen transportation are discussed. At first, the regulatory background and level of safety are presented. In the second part, the modelling of consequence due to sudden rupture of pressure receptacles is explained. Finally, the results are used to define a limit for consequence to enable an acceptable and safe transport of hydrogen.
The Binder Jetting BJ process is one of the most versatile additive manufacturing technologies in use. In this process a binder is locally jetted into a powder bed for the consolidation of a 3D structure, layer by layer. Basically, all materials which can be provided as a flowable powder and, thus, spreadable to a thin layer, can be processed. Metals, ceramics and polymers are processable, but also materials from nature, such as sand, wood sawdust and insect frass. Moreover, the BJ technology is adapted to large building volumes of some cubic meters easily. Besides these striking advantages, the manufacture of ceramic parts by BJ is still challenging, as the packing density of the powder bed is generally too low and the particle size of a flowable powder too large for a successful densification of printed parts in a subsequent sintering step to an advanced ceramic product. After an introduction of binder jetting in general and highlighting some examples, strategies for obtaining dense ceramic parts by BJ will be introduced.
Regarding feedstocks for the additive manufacturing (AM) of ceramics, two features are most critical in classical powder based AM processes: a high particle packing density (typically >50% TD) must be achieved with very fine particles (typically submicron) in order to ensure sufficient sintering activity. Three innovative approaches will be introduced to overcome this problem:
1. Layer wise slurry deposition: The use of water based ceramic slurries as feedstock for the additive manufacture of ceramics has many advantages which are not fully exploit yet. In the layerwise slurry deposition (LSD) process a slurry with no or low organic content is repetitively spread as thin layers on each other by means of a doctor blade. During the deposition, the ceramic particles settle on the previously deposited and dried material to form thin layers with a high packing density (55-60%). The LSD therefore shares aspects both of tape casting and slip casting. The LSD differentiates from the classical powder-based AM layer deposition, which typically achieves with a flowable coarse grained powder a low packing density (35-50%) only, consequently hindering the ability of sintering ceramic parts to full density. The LSD is coupled with the principles of selective laser sintering (SLS) or binder jetting, to generate novel processes which take advantage of the possibility of achieving a highly dense powder-bed.
2. Laser induced slip casting: Contrary to the LSD process, which requires drying of each individual layer, the direct interaction of ceramic slurries with intense laser radiation, for the laser induced slip casting (LIS), is a promising approach for the additive manufacture of voluminous parts.
3. Gas flow assisted powder deposition: By the application of a vacuum pump a gas flow is realized throughout the powder bed. This gas flow stabilizes the powder bed and results into an enhanced flowability and packing density of the powder during layer deposition.
The presentation will provide a detailed discussion of potentialities and issues connected to the mentioned technologies and will describe the most recent developments in their application to technical ceramics.
Im Verbundprojekt R-Rhenania wird eine industrielle Demonstrationsanlage am Standort der Monoverbrennungsanlage Altenstadt der Firma Emter errichtet und im Jahr 2024 den Betrieb aufnehmen. Die vorhandene Rostfeuerung-Monoverbrennung wird so umgebaut, dass ein neues thermochemisches Verfahren integriert werden kann, welches hochwirksame und schadstoffarme Dünger produziert (bis zu 17.000 t/a). Die thermochemischen Produkte werden in Gefäß- und Feldversuchen im ökologischen Landbau auf ihre Düngewirkung getestet. Die Umweltverträglichkeit der Demonstrationsanlage wird untersucht, wie auch die Übertragbarkeit des Verfahrens auf weitere Regionen.
Um den Klimawandel wirksam zu bekämpfen, ist es entscheidend, fossile Brennstoffe durch erneuerbare Energiequellen wie Wind-, Solar- und Wasserkraft sowie alternative Energieträger, beispielsweise grünen Wasserstoff, zu ersetzen. Offshore-Windenergie spielt hierbei eine zentrale Rolle, da sie dank der Kombination aus globaler Verfügbarkeit, relativ geringen Betriebskosten und fortgeschrittenem technischen Entwicklungsstand besonders geeignet ist, zur regenerativen Stromerzeugung beizutragen. Sie ist zudem ein Schlüsselelement für die Umsetzung des Europäischen Green Deals, der das Ziel verfolgt, bis 2050 Klimaneutralität in der EU zu erreichen. Expertenschätzungen zufolge ist eine Steigerung der aktuellen Kapazität von 25 GW im Jahr 2020 auf etwa 450 GW notwendig, um diese ambitionierten Ziele zu erfüllen.
Bei der Entwicklung zukünftiger Offshore-Windparks, insbesondere in tieferen Gewässern, gewinnen Jacket-Gründungsstrukturen an Bedeutung. Diese Strukturen, die eine höhere Steifigkeit bei geringerem Materialeinsatz im Vergleich zu den bisher vorherrschenden Monopile-Gründungen bieten, basieren auf komplexen, räumlich aufgelösten Konstruktionen, die ähnlich den Öl- und Gasplattformen entwickelt werden. Die Herstellung der Jacketknoten, die bislang überwiegend manuell geschweißt wurden, birgt erhebliches Optimierungspotential. Durch Automatisierung und Digitalisierung der Fertigungsprozesse könnten nicht nur die Effizienz gesteigert, sondern auch die Qualität der Endprodukte durch präzise Überwachung und Kontrolle der Produktionsparameter verbessert werden. Diese technologischen Fortschritte sind für die Skalierung der Offshore-Windenergie und die Erreichung der Klimaziele von entscheidender Bedeutung.
Large-scale experiments have been performed to investigate the possible consequences of realistic amounts of liquified hydrogen (LH2) encountering water. The experiments aimed at simulating an accidental release of LH2 during especially the fuelling of a ship. For liquified natural gas (LNG) it has been demonstrated that when spilled onto water the evaporation rate can be that high that physical explosions occur which are referred as rapid phase transitions (RPTs). It cannot be excluded that RPTs are also possible in the case of LH2. The tests were performed in a 10 m x 10 m x 1.5 m basin filled with water, at the Test Site Technical Safety of the Bundesanstalt für Materialforschung und –prüfung (BAM) in Horstwalde, Germany within a research cooperation between BAM and Gexcon as part of
the SH2IFT program. LH2 releases were established releasing directly from a trailer carrying LH2 through a long flexible double vacuum insulated transfer line. The releases occurred from a height of 50 cm above and 30 cm under the water surface both pointing downwards and 30 cm under the water surface pointing along the water surface too. The release rate was determined based on the weight loss rate of the road tanker which was placed onto load cells. Special blast pressure sensors were used to measure the shock waves generated by the release processes both in the water and in the air. At several locations the gas concentration was measured. Heat radiation was measured at 3 distances from the point of release. High speed,
Infrared (IR) and normal cameras were used to record events and to follow the gas cloud behaviour in time. This includes cameras mounted on a UAV and underwater cameras. Two weather stations were used to measure wind speed, wind direction, temperature and humidity during all tests performed. All investigated release configurations resulted in a very chaotic LH2-water mixing zone, causing considerable evaporation but only minor over pressures.
The main phenomenon observed was an ignition of the released gas cloud, resulting in significant blast wave overpressures and heat radiation to the surroundings. The location of the ignition occurred in free air at some distance from the instrumentation and release location.
Large Scale Experiments have been performed to determine whether a storage vessel containing liquid hydrogen (LH2) and caught in a fire engulfing the vessel can result in a BLEVE (Boiling Liquid Expanding Vapour Explosion) and if so its consequences. The tests were performed at the Test Site Technical Safety of the Bundesanstalt für Materialforschung und –prüfung (BAM) in Germany at the Hydrogen Test Area (H2TA) within a research cooperation between BAM and Gexcon as part of the SH2IFT program. Three tests were performed using double-walled vacuum insulated vessels of 1 m3 volume. The cylindrical Vessels differed in orientation (horizontal or vertical) and the insulation material used (perlite or multi-layer insulation (MLI)). The degree of filling of the vessels was approximately 35-40 % in each of the tests performed. The fire load was provided by a propane fed burner-system positioned under the storage vessel and designed to give a homogeneous fire load. The conditions in the vessel (temperatures and pressure) as well as external effects (heat radiation, blast waves, flame ball development and fragmentation) were measured. All vessels were equipped with K-type thermocouples at several locations at the inner and outer vessel shell. The pressure inside the inner vessel and in the space between the inner and outer vessels (vacuum pressure) was measured. Bolometers were used to measure the heat radiation generated by both the propane fire and that generated by a possible fireball/BLEVE. To measure blast generated by the vessel burst/BLEVEs blast pencils were positioned at up to three locations. Further several cameras were used to monitor the events: normal cameras, infrared (IR)-cameras, high-speed cameras also on board of an UAV. Two of these vessels, a horizontal and a vertical vessel both insulated with perlite withstood the fire loading for 1 hour 20 minutes and 4 hours respectively without catastrophic failure. A horizontal vessel insulated with MLI failed by bursting after 1 hour and 6 minutes resulting in a fireball, fragments, and blast wave.
Diese Hinweisbroschüre erläutert allgemeine Planungsvoraussetzungen und Dimensionierungsregelungen, Baugrundsätze und Zulassungsbedingungen zur Anwendung innovativer Belagsdehnfugensysteme (Fahrbahnübergangskonstruktionen) in hochbeanspruchten Verkehrsflächen des Bundesfernstraßenbereiches. Alle planungsrelevanten, baustoffrelevanten, versuchstechnische, qualitätssichernden und baupraktischen Aspekte werden zur Unterstützung der Straßenbauverwaltungen, der Lieferfirmen und Ausführungsbetriebe erläutert. Die Veröffentlichung stellt eine technische Analyse aus Erfahrungssammlungen und Auswertung praktischer Erkenntnisse dar.
A semi-automatic thermographic procedure for the assessment of the welded area of resistance projection welded joints has been developed. Currently, to assess the quality of RPW joints destructive tests are used and the more commonly used non-destructive technique is the ultrasonic one. The possibility for a quantitative evaluation of the welded area by thermographic technique has been proved by means of an innovative procedure applied on steel RPW joints with ‘as it’ surface conditions. Measurements obtained by thermography and ultrasound have been compared, to verify the developed procedure.