Technologien zur Speicherung von Wasserstoff. Teil 1: Wasserstoffspeicherung im engeren Sinn

The efficient and dense storage of hydrogen still is a challenge for research and development. Next to compression and liquefaction, there are a number of alternative approaches, which try to enhance storage density by bonding hydrogen to another substance. Physisorbing as well as chemisorbing organic and inorganic carrier systems are possible. Many of these technologies have not yet exceeded the technology readiness level of lab‐scale tests. However, some of the technologies have already reached significantly higher technological levels. The first part of this study discusses storage approaches with recovery of elemental hydrogen.     

Technologien zur Speicherung von Wasserstoff. Teil 2: Irreversible Konversion und Technologievergleich

Hydrogen storage primarily means storage of a chemical substance. However, it is also often considered as a form of energy storage. Since many technologies for storing hydrogen are based on a chemical conversion anyway, it is reasonable to ask whether the backwards conversion to release hydrogen again is mandatory. If hydrogen is for example converted by a chemical reaction into a hydrocarbon, it can be meaningful to directly combust this hydrocarbon. Such processes open new routes for the utilization of hydrogen energy. The respective technologies are introduced and a comparison to storage options with recovery of elemental hydrogen is presented.     

Die Zerkleinerung von Metallen in Hammerreißern (Shredder)

Size Reduction of Metals in Shredders Size reduction is of cardinal importance in the recycling of scrap and waste. The choice of size reduction machines is critically dependent on the properties and bonding conditions of the components present in the waste or scrap. Shredders have become widely used for the size reduction of various kinds of scrap. Size reduction of metals in shredders requires sufficiently deformation of the pieces of material (bending to compaction), which leads to cracking. Tensile loads con combination with bending and torsion can enlarge the cracks and ultimately lead to break‐up of the pieces of metal. Reduction of the circumferential velocity of the shredding hammers will increase the energy required for the compaction preceding size reduction. Hence, shredders should be operated with maximum possible circumferential velocities.     

Ammoniaksynthese als Beispiel einer stofflichen Nutzung von intermittierend erzeugtem Wasserstoff

Producing hydrogen‐rich chemicals, such as methane, ammonia or methanol, from renewable energy may foster the integration of renewables into the current energy system. Here, a flexible ammonia synthesis concept is introduced, which is then compared to the widely discussed power‐to‐gas concepts on a technical and economic level. The current ammonia prices result in comparably high hydrogen‐specific revenues, which imply the ability to operate the system more profitable under fluctuating electricity prices and thereby increase the plant capacity factor.     

Zur Reaktion von atomarem Wasserstoff mit Cyclopenten und Cyclohexen in der Gasphase

About the Reaction of Hydrogen Atoms with Cyclopentene and Cyclohexene in the Gas Phase The reaction of hydrogen atoms with cyclopentene and cyclohexene has been investigated in an isothermal flow-system (298 K) at a pressure of 130 Pa. 12 products of the cyclopentene reaction and 17 products of the cyclohexene reaction were identified by gas chromatography. The quantitative studies show, that the main reactions of the cyclopentene system are the hydrogenation to cyclopentane and the chemical activated decay to methane; cyclohexene reacts especially by hydrogenation to cyclohexane and ring-isomerisation to methylcyclopentane.