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Hans Skarsvåg
SINTEF Energy Research, Postboks 4761 Torgarden, 7465 Trondheim, Norway

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Journal article
Published: 06 August 2021 in Energies
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Liquid hydrogen (LH2) spills share many of the characteristics of liquefied natural gas (LNG) spills. LNG spills on water sometimes result in localized vapor explosions known as rapid phase transitions (RPTs), and are a concern in the LNG industry. LH2 RPT is not well understood, and its relevance to hydrogen safety is to be determined. Based on established theory from LNG research, we present a theoretical assessment of an accidental spill of a cryogen on water, including models for pool spreading, RPT triggering, and consequence quantification. The triggering model is built upon film-boiling theory, and predicts that the mechanism for RPT is a collapse of the gas film separating the two liquids (cryogen and water). The consequence model is based on thermodynamical analysis of the physical processes following a film-boiling collapse, and is able to predict peak pressure and energy yield. The models are applied both to LNG and LH2, and the results reveal that (i) an LNG pool will be larger than an LH2 pool given similar sized constant rate spills, (ii) triggering of an LH2 RPT event as a consequence of a spill on water is very unlikely or even impossible, and (iii) the consequences of a hypothetical LH2 RPT are small compared to LNG RPT. Hence, we conclude that LH2 RPT seems to be an issue of only minor concern.

ACS Style

Lars Odsæter; Hans Skarsvåg; Eskil Aursand; Federico Ustolin; Gunhild Reigstad; Nicola Paltrinieri. Liquid Hydrogen Spills on Water—Risk and Consequences of Rapid Phase Transition. Energies 2021, 14, 4789 .

AMA Style

Lars Odsæter, Hans Skarsvåg, Eskil Aursand, Federico Ustolin, Gunhild Reigstad, Nicola Paltrinieri. Liquid Hydrogen Spills on Water—Risk and Consequences of Rapid Phase Transition. Energies. 2021; 14 (16):4789.

Chicago/Turabian Style

Lars Odsæter; Hans Skarsvåg; Eskil Aursand; Federico Ustolin; Gunhild Reigstad; Nicola Paltrinieri. 2021. "Liquid Hydrogen Spills on Water—Risk and Consequences of Rapid Phase Transition." Energies 14, no. 16: 4789.

Journal article
Published: 01 June 2021 in International Journal of Greenhouse Gas Control
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To design and operate safe and efficient CO2-transportation systems for CO2 capture and storage (CCS), engineers need simulation tools properly accounting for the fluid and thermodynamics of CO2. As the transportation systems evolve into networks, it becomes important that these tools also account for impurities in the CO2, which may significantly affect the thermophysical properties, directly impacting system design and safety. Tube-depressurization experiments provide crucial data to develop and validate models describing transient multiphase multicomponent flow in pipes. In this work, we perform experiments in a new facility with dense and fast instrumentation for both pressure and temperature. One experiment is for CO2 with 1.8 mol % N2, and one has 1.92 mol % He, both starting from 12 MPa and 25 ∘C. In order to quantify the effect of impurities, the experiments are compared to results for pure CO2 and analysed on the background of simulations. We employ a homogeneous equilibrium model (HEM) augmented in this work to account for the appearance of solid CO2 in CO2 mixtures. We observe that the moderate amounts of impurities significantly influence both pressure and temperature dynamics. In particular, the ‘pressure plateau’, a key quantity for the assessment of running-ductile fracture, increases as much as 4 MPa for CO2-He compared to pure CO2. A further insight is that models must account for solid CO2 in order to capture the correct temperature development as the pressure decreases towards atmospheric conditions.

ACS Style

Svend Tollak Munkejord; Han Deng; Anders Austegard; Morten Hammer; Ailo Aasen; Hans L. Skarsvåg. Depressurization of CO2-N2 and CO2-He in a pipe: Experiments and modelling of pressure and temperature dynamics. International Journal of Greenhouse Gas Control 2021, 109, 103361 .

AMA Style

Svend Tollak Munkejord, Han Deng, Anders Austegard, Morten Hammer, Ailo Aasen, Hans L. Skarsvåg. Depressurization of CO2-N2 and CO2-He in a pipe: Experiments and modelling of pressure and temperature dynamics. International Journal of Greenhouse Gas Control. 2021; 109 ():103361.

Chicago/Turabian Style

Svend Tollak Munkejord; Han Deng; Anders Austegard; Morten Hammer; Ailo Aasen; Hans L. Skarsvåg. 2021. "Depressurization of CO2-N2 and CO2-He in a pipe: Experiments and modelling of pressure and temperature dynamics." International Journal of Greenhouse Gas Control 109, no. : 103361.

Journal article
Published: 09 December 2020 in Journal of Loss Prevention in the Process Industries
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Transport of liquefied natural gas (LNG) by ship occurs globally on a massive scale. The large temperature difference between LNG and water means LNG will boil violently if spilled onto water. This may cause a physical explosion known as rapid phase transition (RPT). Since RPT results from a complex interplay between physical phenomena on several scales, the risk of its occurrence is difficult to estimate. In this work, we present a combined fluid-dynamic and thermodynamic model to predict the onset of delayed RPT. On the basis of the full coupled model, we derive analytical solutions for the location and time of delayed RPT in an axisymmetric steady-state spill of LNG onto water. These equations are shown to be accurate when compared to simulation results for a range of relevant parameters. The relative discrepancy between the analytic solutions and predictions from the full coupled model is within 2% for the RPT position and within 8% for the time of RPT. This provides a simple procedure to quantify the risk of occurrence for delayed RPT for LNG on water. Due to its modular formulation, the full coupled model can straightforwardly be extended to study RPT in other systems.

ACS Style

Karl Yngve Lervåg; Hans Langva Skarsvåg; Eskil Aursand; Jabir Ali Ouassou; Morten Hammer; Gunhild Reigstad; Åsmund Ervik; Eirik Holm Fyhn; Magnus Aa. Gjennestad; Peder Aursand; Øivind Wilhelmsen. A combined fluid-dynamic and thermodynamic model to predict the onset of rapid phase transitions in LNG spills. Journal of Loss Prevention in the Process Industries 2020, 69, 104354 .

AMA Style

Karl Yngve Lervåg, Hans Langva Skarsvåg, Eskil Aursand, Jabir Ali Ouassou, Morten Hammer, Gunhild Reigstad, Åsmund Ervik, Eirik Holm Fyhn, Magnus Aa. Gjennestad, Peder Aursand, Øivind Wilhelmsen. A combined fluid-dynamic and thermodynamic model to predict the onset of rapid phase transitions in LNG spills. Journal of Loss Prevention in the Process Industries. 2020; 69 ():104354.

Chicago/Turabian Style

Karl Yngve Lervåg; Hans Langva Skarsvåg; Eskil Aursand; Jabir Ali Ouassou; Morten Hammer; Gunhild Reigstad; Åsmund Ervik; Eirik Holm Fyhn; Magnus Aa. Gjennestad; Peder Aursand; Øivind Wilhelmsen. 2020. "A combined fluid-dynamic and thermodynamic model to predict the onset of rapid phase transitions in LNG spills." Journal of Loss Prevention in the Process Industries 69, no. : 104354.