Development and characterization of multi-streams heat exchangers for liquefaction cycle analysis in the contextof hydrogen mobility

Sammanfattning: This paper presents the master thesis work done at ArianeGroup on the development and characterization of multi-streams heat exchangers for liquefaction cycle analysis in the context of hydrogen mobility. In 2015, the Paris Agreements aimed at strengthening the global response to the threat of climate change by keeping the temperature rise below 1.5°C. Hydrogen is a potential alternative to fossil fuels to limit the emissions, thus governments and industries are investing in and developing technologies to exploit this energy. Hydrogen is produced from various sources such as renewable energy sources, but also fossil fuels and surplus energy (heatand electricity). Once produced, the hydrogen is cooled and liquefied for efficiency purposes through liquefaction cycles. ArianeGroup is an aerospace company developing and building launchers providing Europe’s access to space. Hydrogen is used as a liquid fuel for most of its rocket engines such as the Vulcain motor which is the engine of the main stage of the Ariane5 launcher. The company has thus acquired expertise on cryogenic hydrogen and is able to apply this knowledge to other project in other domains not restricted to space applications. To meet the increasing demand of hydrogen and become independent in its hydrogen production, ArianeGroup has done preliminary studies in the area of hydrogen liquefaction. This thesis continued the studies onliquefaction by developing models of multi-streams heat exchanger components to then simulate complex andoptimized liquefaction cycle. A preliminary modeling of multi-streams heat exchanger was done on Matlab and validated. The simulations give accurate results with regards to test cases when considering only para-hydrogen. Multi-streams heat exchangercomponents were coded on PROOSIS and validated. Liquefaction cycles were simulated such as the Collins Cycle. A new cycle optimized for production was also reproduced. With the corrective fluxes needed to match the required temperatures at some stations, the closed cycle simulations gives similar results to the ASPEN model of this new cycle. The same studies were also performed on Amesim which enabled to introduce the geometry of heat exchangers. Shell and tube heat exchangers were considered. The steady-state simulations showed that quite some time is required for the systems to converge to their nominal point.