Modelling and simulation of cryogenic tank systems onboard vessels

Συκάς, Δημήτριος; Sykas, Dimitrios

dc.contributor.author	Συκάς, Δημήτριος	el
dc.contributor.author	Sykas, Dimitrios	en
dc.date.accessioned	2024-12-20T08:39:26Z
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/60579
dc.identifier.uri	http://dx.doi.org/10.26240/heal.ntua.28275
dc.rights	Αναφορά Δημιουργού-Μη Εμπορική Χρήση-Όχι Παράγωγα Έργα 3.0 Ελλάδα	*
dc.rights.uri	http://creativecommons.org/licenses/by-nc-nd/3.0/gr/	*
dc.subject	Κρυογενικά	el
dc.subject	Δεξαμενές	el
dc.subject	Μοντελοποίηση	el
dc.subject	Προσομοίωση	el
dc.subject	Υγρά	el
dc.subject	Cryogenic	en
dc.subject	Liquids	en
dc.subject	Modelling	en
dc.subject	Simulation	en
dc.subject	Tanks	en
dc.title	Modelling and simulation of cryogenic tank systems onboard vessels	en
heal.type	bachelorThesis
heal.classification	Marine engineering	en
heal.dateAvailable	2025-12-19T22:00:00Z
heal.language	en
heal.access	embargo
heal.recordProvider	ntua	el
heal.publicationDate	2024-07
heal.abstract	In response to the urgent need to decarbonise the maritime sector, there has been notable adoption of greener fuels, like liquefied natural gas (lng). This shift is accompanied by considerable research efforts on net-zero fuels for use in the maritime sector – with the most promising candidates being ammonia and hydrogen. Furthermore, both ashore on-board carbon capture technologies are being investigated. If carbon capture operations manifest in a global scale, there would be a need to transport the captured carbon dioxide through ships. Transporting the aforementioned substances is usually done by liquefication, either through pressurisation, cooling to cryogenic conditions, or a combination of both. The storage of substances in cryogenic conditions exposes them to heat ingress from the environment, resulting in the production of boil-off gas (BOG), which contributes to the increase of the tank’s pressure. Uncontrolled bog generation can lead to overpressure, posing safety risks to the crew and potentially to the environment as well, should a toxic cargo leak into the atmosphere. In the present thesis a systematic approach to modelling the thermodynamic properties of cryogenic mixtures, including boil-off, is proposed. The developed model respects the mass and energy conservation principles across the liquid and gaseous phases. It also considers the different value of heat ingress through the segment of the tank’s walls in contact with the liquid and the one in contact with the vapour. Vapour-liquid equilibrium (VLE) is not considered throughout the system but is confined in a hypothetical thin-film interface between phases. All studied substances are considered real fluids or mixtures. Through numerous validation tests, it was confirmed that the developed model successfully simulated a realistic LNG mixture, while also producing logical results for ammonia and carbon dioxide, despite the lack of experimental data about the cryogenic storage of these substances in marine environments. The assumptions made to keep the model simple, however, resulted in inadequate performance in some hydrogen simulations. Overall, it was found that installation of BOG removal pumps is necessary for the transportation of all studied substances. The sizing of those pumps should be made based on the desired performance primarily during the filling of the tank, as that was the point when the highest pressure increase rate was observed.	en
heal.advisorName	Δημόπουλος, Γεώργιος	el
heal.advisorName	Dimopoulos, Georgios	en
heal.committeeMemberName	Παπαδόπουλος, Χρήστος	el
heal.committeeMemberName	Τσούβαλης, Νικόλαος	el
heal.committeeMemberName	Papadopoulos, Christos	en
heal.committeeMemberName	Tsouvalis, Nikolaos	en
heal.academicPublisher	Εθνικό Μετσόβιο Πολυτεχνείο. Σχολή Ναυπηγών Μηχανολόγων Μηχανικών. Τομέας Ναυτικής Μηχανολογίας	el
heal.academicPublisherID	ntua
heal.numberOfPages	117 σ.	el
heal.fullTextAvailability	false