Method and system for computing a transition parameter of a liquefied gas storage medium

Patent metadata

Field	Value
Publication number	US-12111014-B2
Application number	US-202217950882-A
Country	US
Kind code	B2
Filing date	Sep 22, 2022
Priority date	Sep 30, 2021
Publication date	Oct 8, 2024
Grant date	Oct 8, 2024

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.

First claim

What is claimed is:

1. 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 ρ l,i and ρ v,i , and initial internal mass energies U l,i and U v,i on the basis of an initial liquid phase temperature T l,i , an initial vapour phase temperature T v,i , an initial vapour phase pressure P i , an initial liquid phase volume V l,i and an initial liquid phase composition x l,i ;
determining, for the liquid phase and the vapour phase in the final state ( 9 ), final mass densities ρ l,f and ρ v,f , final internal mass energies U l,f and U v,f , and final mass enthalpies H l,f and H v,f on the basis of an equation of state and a final vapour phase pressure P f , the final pressure of the vapour phase P f 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 P i ;
computing the transition parameter using the following equation:
τ( {dot over (Q)}+{dot over (m)} v ( H v,f −Ū )+ {dot over (m)} l ( H l,f −Ū ))=ρ l,i V l,i ( Ū−U l,i )+ρ v,i ( V t −V l,i )( Ū−U v,i )+ρ v,f V t ( U v,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, V t corresponds to a total volume of the tank and with

U
_

=

ρ

l
,
f

⁢

U

l
,
f

-

ρ

v
,
f

⁢

U

v
,
f

ρ

l
,
f

-

ρ

v
,
f

.

2. 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 ρ l,i and ρ v,i , and initial internal mass energies U l,i and U v,i on the basis of an initial liquid phase temperature T l,i , an initial vapour phase temperature T v,i , an initial vapour phase pressure P i , an initial liquid phase volume V l,i and an initial liquid phase composition x l,i ;
determining, for the liquid phase and the vapour phase in the final state ( 9 ), final mass densities μ l,f and ρ v,f , final internal mass energies U l,f and U v,f , and final mass enthalpies H l,f and H v,f on the basis of an equation of state and a final vapour phase pressure P f , the final pressure of the vapour phase P f 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 P i ;
computing the transition parameter using the following equation:
τ( {dot over (Q)}+{dot over (m)} v ( H v,f −Ū )+ {dot over (m)} l ( H l,f −Ū ))=ρ l,i V l,i ( Ū−U l,i )+ρ v,i ( V t −V l,i )( Ū−U v,i )+ρ v,f V t ( U v,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, V t corresponds to a total volume of the tank and with

U
_

=

ρ

l
,
f

⁢

U

l
,
f

-

ρ

v
,
f

⁢

U

v
,
f

ρ

l
,
f

-

ρ

v
,
f

.

3. The method according to claim 1 , wherein the storage medium comprises a plurality of tanks ( 2 , 4 , 5 , 6 , 7 and 11 ) and, f

Assignees

• Gaztransport Et Technigaz

Inventors

• Bonnissel Marc

Classifications

• F17C2270/0105

  Ships · CPC title

• F17C2265/031

  by discharge · CPC title

• F17C2250/0626

  Pressure · CPC title

• F17C2250/0447

  Composition; Humidity · CPC title

• F17C2250/0439

  Temperature · CPC title