Method and system for computing a transition parameter of a liquefied gas storage medium
AssigneeGaztransport Et Technigaz
InventorMarc Bonnissel
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Abstract
The present invention relates to a computer-implemented method and system for computing a transition parameter of a liquefied gas storage medium, the storage medium having at least one sealed and unrefrigerated tank, the transition parameter characterizing an evolution of a two-phase mixture contained in the sealed and unrefrigerated tank between an initial state and a final state, the two-phase mixture including a liquid phase and a vapour phase, the transition parameter may be a duration of the transition, a liquid bleeding rate or a vapour bleeding rate.
Claims17
A computer-implemented method for computing a transition parameter of a liquefied gas storage medium, the storage medium comprising at least one sealed and unrefrigerated tank (2, 4, 5, 6, 7 or 11) equipped with a safety valve (20), the transition parameter characterizing an evolution of a two-phase mixture (13) contained in the sealed and unrefrigerated tank between an initial state (8) and a final state (9), the two-phase mixture including a liquid phase and a vapour phase, wherein said transition parameter is selected in a group consisting of a duration of the transition τ, a liquid bleeding rate {dot over (m)}l or a vapour bleeding rate {dot over (m)}v, the method comprising the steps of:
- determining, for the liquid phase and the vapour phase in the initial state (8), initial mass densities ρl,i and ρv,i, and initial internal mass energies Ul,i and Uv,i on the basis of an initial liquid phase temperature Tl,i, an initial vapour phase temperature Tv,i, an initial vapour phase pressure Pi, an initial liquid phase volume Vl,i and an initial liquid phase composition xl,i;
- determining, for the liquid phase and the vapour phase in the final state (9), final mass densities ρl,f and ρv,f, final internal mass energies Ul,f and Uv,f, and final mass enthalpies Hl,f and Hv,f on the basis of an equation of state and a final vapour phase pressure Pf, the final pressure of the vapour phase Pf being less than or equal to the setting pressure of the safety valve (20) and greater than or equal to the initial pressure of the vapour phase Pi;
- computing the transition parameter using the following equation:
- τ({dot over (Q)}+{dot over (m)}v(Hv,f−Ū)+{dot over (m)}l(Hl,f−Ū))=ρl,iVl,i(Ū−Ul,i)+ρv,i(Vt−Vl,i)(Ū−Uv,i)+ρv,fVt(Uv,f−Ū)
- in which {dot over (Q)} corresponds to an energy contribution by heat ingress through the walls of a tank per unit of time, Vt corresponds to a total volume of the tank and with
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A computer-implemented method for computing a transition parameter of a liquefied gas storage medium, the storage medium comprising at least one sealed and unrefrigerated tank (2, 4, 5, 6, 7 or 11) equipped with a vacuum breaker valve (21), the transition parameter characterizing an evolution of a two-phase mixture (13) contained in the sealed and unrefrigerated tank between an initial state (8) and a final state (9), the two-phase mixture including a liquid phase and a vapour phase, wherein said transition parameter is selected in a group consisting of a duration of the transition τ, a liquid bleeding rate {dot over (m)}l or a vapour bleeding rate {dot over (m)}v, the method comprising the steps of:
- determining, for the liquid phase and the vapour phase in the initial state (8), initial mass densities ρl,i and ρv,i, and initial internal mass energies Ul,i and Uv,i on the basis of an initial liquid phase temperature Tl,i, an initial vapour phase temperature Tv,i, an initial vapour phase pressure Pi, an initial liquid phase volume Vl,i and an initial liquid phase composition xl,i;
- determining, for the liquid phase and the vapour phase in the final state (9), final mass densities μl,f and ρv,f, final internal mass energies Ul,f and Uv,f, and final mass enthalpies Hl,f and Hv,f on the basis of an equation of state and a final vapour phase pressure Pf, the final pressure of the vapour phase Pf is greater than or equal to the setting pressure of the vacuum breaker valve (21) and less than or equal to the initial pressure of the vapour phase Pi;
- computing the transition parameter using the following equation:
- τ({dot over (Q)}+{dot over (m)}v(Hv,f−Ū)+{dot over (m)}l(Hl,f−Ū))=ρl,iVl,i(Ū−Ul,i)+ρv,i(Vt−Vl,i)(Ū−Uv,i)+ρv,fVt(Uv,f−Ū)
- in which {dot over (Q)} corresponds to an energy contribution by heat ingress through the walls of a tank per unit of time, Vt corresponds to a total volume of the tank and with
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Dependencies are inferred from the claim text.