FR2840971A1 - Storage of compressible fluid in gaseous form in storage tank involves supplying temperature and pressure lower than final conditions to obtain denser, cooled fluid, which is released as gas into storage tank to fill it - Google Patents

Abstract

Compressible fluid is supplied at a temperature and pressure lower than the final conditions to obtain a denser, cooled fluid. A preset quantity of fluid is admitted into a closed, thermally-insulated vessel inside the storage tank, and then released as a gas into the storage tank to fill it and bring the fluid progressively to the desired final temperature and pressure conditions The cooled fluid is a refrigerated gas, liquid or solid and transfer to the internal volume of the storage tank involves heating the refrigerated gas, evaporating the refrigerated liquid or sublimation of the refrigerated solid respectively. Alternatively, the fluid may be a two-phase mixture (solid/liquid or liquid/gas) and transfer to the storage tank involves a melting/evaporation or an evaporation/heating process. The fluid is admitted into the vessel in a controlled manner as a function of the required final temperature and pressure conditions. The fluid can be provided from a cryogenic source. The fluid can be released from the vessel into the tank in a series of admissions of preset quantities of denser refrigerated fluid to optimize the storage conditions of the fluid. An Independent claim is included for a device for carrying out the above process, comprising a closed, thermally-insulated vessel inside a storage tank; an inlet valve for admitting a preset quantity of fluid supplied preferably in a denser, refrigerated form; and means of connecting the space containing the denser refrigerated fluid to the internal volume of the storage tank to allow passage of the preset quantity progressively into the storage tank in the form of a gas at the required final temperature and pressure. The device also includes means of controlling the means of admission The storage tank is cylindrical, and the closed vessel is made of a cylindrical metal skin held inside the storage tank on thermally insulated supports. The axis of revolution of the tank and vessel are parallel, horizontal and offset. The means of connecting the vessel to the internal volume of the tank comprises an escape valve with a throttle. The tank also has a distribution valve for the gas stored. The inlet valve and distribution valve are placed along the axis of symmetry of the tank. The vessel is connected to the inlet valve via a rotating joint. The assembly formed by the vessel and the denser refrigerated fluid admitted into it rotates about the tank's axis of symmetry, to allow the horizon of the saturated vapor pressure space to stay below the inlet valve, thus reducing the risk of direct expansion of the fluid into the reservoir in case of shock or uncontrolled displacement of the storage tank.

Description

\ The invention relates to a method of gas phase storage of a

  compressible fluid and a corresponding storage device.

  The operation of filling a fluid reservoir consists, in its most general definition, of bringing to this reservoir an amount of fluid such as the sum of the amount supplied and the amount of fluid that this reservoir contained, beforehand. this filling operation, equal

to the capacity of this tank.

  The capacity of the reservoir can be evaluated either in mass, in volume or in pressure of the fluid to be stored. The pressure is more

  commonly used for single-phase compressible fluids.

  The reservoir can, moreover, be defined by its internal geometric volume, also called "water volume" in the corresponding technical field, and by its maximum filling pressure. The value of the maximum pressure retained must necessarily take into account the

  resistance of the tank to pressure as well as safety coefficients.

  When the reservoir is intended to contain a compressible fluid, the quantity of gas contained in the reservoir during or after filling can be determined either by peace, when the mass of the reservoir and the mass of its accessories, the tare, is known , either by measuring the pressure and the temperature of the fluid, when the "water volume" of the reservoir on the one hand and the physical characteristics of the fluid on the other hand, in particular the mass

  volume of the latter, known wind.

  There are two well-known procedures for filling reservoirs with compressible fluid, which consist, respectively, of: a) pressurizing the reservoir from a mother source by means of either a pump, if the mother source is at a pressure lower than the final pressure retained for the tank, or a regulator in the opposite case. Cascade filling procedures, based on this principle,

have been described in particular.

  b) filling with peace: the tare being known, we can

  deduct the mass of fluid contained in the latter.

  - i The filling procedure by pressurization becomes more complex when, during transfers of the fluid to the reservoir, this fluid being subjected to different compression and expansion cycles, the fluid and the reservoir are subjected to successive heating / cooling. This may result in uncertainty about the temperature of the assembly and therefore about the quantity stored. The filling procedure by weighing appears all the more imprecise when the ratio of the mass of fluid to the mass of the container, including the tare, is low. This is in particular the case, for example, for fluids constituted by light gases such as hydrogen. In this situation, the

  accurate ratio is commonly less than 10%.

  Consequently, a rigorous measurement of the quantity of stored fluid requires very precise equipment and a very precise vice weighing procedure for each container. A rough estimate of

  the average tare cannot be used.

  In all cases, regardless of the filling procedure by pressurization or by weighing used, the duration of filling operations is a significant economic parameter, due to the immobilization of the filling installation and space, on the one hand, reservoirs and

  systems to which these tanks are linked, on the other hand.

  In fact, the duration of the filling operations determines the capacity

  daily operational maximum of filling of an installation.

  Different means for accelerating the filling operations can be implemented: - increase in the instantaneous mass flow rate of fluid entering the reservoir. Such an increase can be obtained by increasing the density of the fluid, by lowering the temperature and increasing the pressure of the latter, and by reducing the pressure losses; - increase in the efficiency of the filling device by setting up quick connections, judicious arrangement of the filling posse, organization and optimization of the process, by execution of certain operations in masked time such as, for example, operations of

  sorting, checking, labeling or others.

  The implementation of the increase in instantaneous mass flow rate by increase in pressure is technically limited by safety constraints. In particular, the equipment and connecting devices dolvent withstand mechanical stresses and constraints such as "fatigue", high flow velocities in the pipes, succession of expansion and significant compressions creating thermal cycles which superimpose, on the aforementioned mechanical constraints, thermal stresses likely to accentuate the phenomena of "fatigue", risks of critical heating by adiabatic compression, damaging consequences in case

leakage or rupture.

  The implementation of the increase in density by cooling the fluid makes it possible to reduce the aforementioned risks, inherent in the process of increasing pressure, but presents the drawback of a non-negligible consumption of energy. In particular, for fluids constituted by gases such as nitrogen, argon and oxygen, for example, an increase in density, without excessive increase in pressure, can be obtained by

cryogenic liquefaction.

  For certain liquefiable gases at moderate temperature and pressure such as carbon dioxide, propane, nitrous oxide, for example, the increase in density can be obtained by a combination of the two

  pressurization and cooling process.

  In particular, internal combustion engine systems, implementing operations for supplying the engine with liquefied gas, liquefied air operating as cryogenic gas, and liquid natural gas, the latter being refrigerated and then expanded by successive stages to produce the

  motor work, have been described by US patent 4 359 118.

  However, the aforementioned gases are stored in a conventional manner.

  The present invention relates to the implementation of a method of gas phase storage of a compressible fluid and a specific storage device using the cooling process, in the absence of

  disadvantages inherent in such an operating mode.

  Indeed, filling a storage tank with a cooled fluid inevitably leads to cooling, at least locally, the walls or structures of the tank. Such local cooling is likely to cause, in particular by thermal shock, tensions and deformations or a

  embrittlement of the latter's envelope.

  Another object of the present invention is. consequently, the implementation of a method of gas phase storage of a compressible fluid and of a specific storage device making it possible to carry out rapid filling operations, from a cooled fluid, in [' absence of any

  alteration of the device or the storage tank thereof.

  Another object of the present invention is. in addition, the implementation of a method of gas phase storage of a compressible fluid and a specific storage device, thanks to which the need to implement a heat exchanger upstream of the tank, depending on the solution most conventional known, in order to heat the fluid before entering the tank thereof, is eliminated, this solution requiring a large space to ensure ['proper installation of the evaporator and also involving; that the latter is able to withstand the filling pressure. Another object of the present invention is. in addition, the implementation of a gas phase storage process of a compressible fluid and a specific storage device, thanks to which the need to "cool" the storage tank, prior to filling this the latter from a cooled fluid, according to another solution known from the state of the art, is eliminated. Such cooling procedures are lengthy and consequently reduce the storage capacity of all of the

facilities.

  Another object of the present invention is. finally, taking into account the abovementioned abolition of the chilling procedure, the covering of specific storage tanks which are lighter and of a much simpler design, from common and cheap materials, the structural imperatives and design of conventional tanks, subjected to the cooling procedure, requirements relating to the use of suitable materials offering good resilience at low temperatures, such as nickel steels, austenitic steels

  or light alloys, wind substantially suppressed.

  The method of gas phase storage, in a storage tank, of a compressible fluid under conditions of determined final temperature and pressure of storage, object of the invention, is remarkable in that it consists in bringing the fluid compressible, outside the storage tank, to a state of temperature and pressure lower than the final temperature and pressure conditions of storage determined, to obtain a densified refrigerant, to be admitted, in a closed thermally insulated enclosure, included in the storage tank, a determined quantity of densified refrigerated fluid, to subject the determined quantity of densified refrigerated fluid to a gaseous phase passage in the internal volume of the storage reservoir, in order to gradually bring the fluid in gaseous phase to the state conditions final storage temperature and pressure

  determined and fill the storage tank.

  The device for the gas phase storage of a compressible fluid, in a storage tank, under determined conditions of final temperature and pressure of storage, object of the present invention, is remarkable in that it comprises at least one enclosure closed, thermally insulated, included in the storage tank, intake circuits, in this enclosure, of a determined quantity of the fluid previously supplied in the form of densified refrigerated fluid and circuits for placing in communication the space containing the densified refrigerated fluid inside this closed enclosure with the internal volume of the storage tank. This makes it possible to cause the determined quantity of the fluid in the gaseous phase to pass through this internal volume and to gradually bring the fluid in the gaseous phase to the final temperature and pressure state conditions of

  storage determined to fill the storage tank.

  The method and the device for gas phase storage of a compressible fluid which are the subject of the present invention find application in the conditioning of fluids such as gases, with one or more elements,

especially.

  They will be better understood on reading the description and

  ['observation of the drawings below, in which: - Figure 1 represents, purely by way of illustration, the essential stages of implementation of the process of storage in the gas phase of a compressible fluid, in accordance with the object of the present invention; - Figure 2a shows, by way of illustration, in a sectional view, a specific gas phase storage device for a compressible fluid according to the object of the present invention; - Figure 2b shows, by way of illustration, various details of an alternative embodiment of a device for storing in the gas phase a compressible fluid as shown in Figure 2a; - Figures 3a and 3b show, by way of illustration, details of implementation or construction of a specific gas phase storage device for a compressible fluid in accordance with the object of the invention, such as

  as shown in Figures 2a, 2b or 3a.

  A more detailed description of the phase storage process

  gas in a storage tank for a compressible fluid in accordance with the object of the present invention will now be given in connection with the

figure 1.

  Generally, it is indicated that the final storage temperature and pressure conditions noted (P, T) fs are determined as a function of the nature of the compressible fluid, the storage of which in phase

gas must be carried out.

  As represented in step 1 of FIG. 1, the process which is the subject of the invention consists in bringing the compressible fluid outside the storage tank to a state of temperature and pressure noted (P, T) or below the conditions. of final storage temperature and pressure determined (P, T) fs previously mentioned, in order to obtain a densified refrigerated fluid

RDF note.

  It is understood, in particular, that such an operation can be carried out from any installation adapted as a function of the nature of the compressible fluid considered, this installation being symbolically represented by a container or enclosure which may constitute a cryogenic source, noted

for this reason CS.

  The aforementioned step is then followed by a step 2 consist in admitting, in a closed thermally insulated enclosure, enclosure V, this enclosure being included in the storage tank R. a determined quantity of the fluid

refrigerated densifies RDF.

  By way of nonlimiting example, as shown in FIG. 1 in step 2 thereof, the abovementioned admission operation can be carried out from the abovementioned cryogenic source CS. This operation can be carried out either by direct admission, controlled for example through a valve

  ordered, as will be described later in the description, when the

  CS cryogenic source is at a pressure higher than atmospheric pressure. It is indicated, by way of nonlimiting example, that the thermally insulated closed enclosure V is. at the start, at atmospheric pressure and at

room temperature, for example.

  The precise step 2 is then followed by a step 3 which consists in subjecting the determined quantity of the densified refrigerated fluid QRDF to a passage in gaseous phase in the internal volume of the storage tank R. This operation makes it possible to gradually bring the fluid into gas phase at the final storage temperature and pressure conditions (P'T) fs previously mentioned and to fill, thus, the storage tank R. In Figure 1, we have represented the step consist in subjecting the determined quantity of refrigerated fluid densified at the gaseous phase passage in the internal volume of the storage tank R by the opening of a specific valve allowing the communication of the internal volume of the insulated thermal closed enclosure V and of the internal volume of the storage tank A. The process which is the subject of the present invention is capable of being used for different forms of densified refrigerated fluid, which will be

explained below.

  According to a first mode of implementation, the process which is the subject of the present invention may consist in constituting the densified refrigerated fluid RDF by means of a refrigerated gas. The gas subjected to refrigeration can then be constituted by any type of gas and, in particular, by a gas with one or more elements, such as hydrogen H 2 or methane CH 4, for example, respectively. It will be understood, in particular, that, under these conditions, the densified refrigerated fluid is obtained, for example in a conventional manner, taking into account the liquefaction temperatures of the abovementioned gases. It is understood, in particular, that the temperature to which the gas mentioned above is brought is chosen to be higher than the aforementioned liquefaction temperature in order to avoid

  ['appearance of any dew point and simply obtain a refrigerated gas.

  Under these conditions, the step of transition to the gas phase in the storage tank can consist, advantageously, of a heating.

densified refrigerant.

  By way of nonlimiting example, it is indicated that, for a determined quantity of QRDF densified refrigerant, the precise heating may consist simply in admitting the quantity of precise densified refrigerant in the enclosure V, which is at ambient temperature. The quantity admitted QRDF is then calculated from the equation of state PV nRT or more generally PV = Z (T, P) nRT. It is also understood that the admission of the quantity of densified refrigerated fluid QRDF, then the communication of the internal space of the thermally insulated closed enclosure V, with the internal volume of the reservoir R. can then be carried out sequentially when the equilibrium temperatures and, of course, equilibrium pressures

corresponding, wind obtained.

  By way of nonlimiting example, it is indicated that the thermally insulated closed enclosure can be made of a material which conducts heat, so as to allow heat exchanges between the atmosphere created in the internal volume of the reservoir R and [ densified refrigerated fluid atmosphere created in the thermally insulated closed enclosure V. Of course, as shown in FIG. 1, the thermally insulated closed enclosure V is then isolated, by suitable insulating materials, from any mechanical and thermal contact with the walls of the reservoir R. It is the same for any conduit which allows the implementation of the

  process, as will be explained later in the description.

  According to a second embodiment of the process which is the subject of

  [Invention, the densified refrigerant can be constituted by a refrigerated liquid.

  In such an implementation mode, the gaseous fluid is brought to the liquid state.

  This mode of implementation appears to be more particularly suitable for gases with a relatively high liquefaction temperature such as nitrous oxide or propane. Under these conditions, the fluid is brought to the liquid state according to conventional methods. Consequently, the step of transition to the gas phase in the storage tank then consists of an evaporation of the fluid.

densified refrigerated.

  According to a third mode of implementation of the process which is the subject of the present invention, it is indicated that the densified refrigerated fluid may be constituted by a refrigerated solid, the compressible gaseous fluid being previously brought to the solid state. The operations necessary to bring the compressible fluid to the solid state are known to those skilled in the art. The concept covers, in particular, any product of the foam type, or where applicable pulverulent, the process which is the subject of the present invention, in this situation, being able to be used in particular for carbon dioxide, carbon dioxide being brought to its state solid refrigerated densified as carbon dioxide snow. In this situation, the step of transition to the gas phase in the storage tank R then consists in a sublimation of the densified refrigerated fluid. For the implementation of the process which is the subject of the present invention in the case of carbon dioxide, the latter can easily be implemented from carbon dioxide snow reserves, for example, normally available.

in trade.

  Finally, according to a fourth mode of implementation of the process which is the subject of the present invention, it is indicated that the densified refrigerated fluid may be constituted by a two-phase mixture, solid / liquid mixture or liquid / gas mixture. With regard to the solid / liquid mixture, it is indicated that the latter appears to be particularly suitable for implementing the process which is the subject of the invention when the compressible fluid is hydrogen, for example, the corresponding two-phase mixture being then obtained for a temperature close to the solidification temperature of the hydrogen. The corresponding two-phase solid / liquid mixture is then obtained in the form of a

  mud, which can be kept in a cryogenic source for example.

  In this situation, the step of transition to the gas phase in the storage tank R then consists of a melting / evaporation operation, the solid part of the two-phase mixture being subjected to melting to give the liquid part and the liquid part being subjected at evaporation, these

  operations being, of course, substantially simultaneous.

  When the two-phase mixture is constituted by a liquid / gas mixture, the process which is the subject of the present invention appears to be particularly well suited for a compressible fluid such as nitrogen or oxygen, which are then brought to a temperature close to their

  respective boiling point.

  In this situation, the step of transition to the gas phase in the storage tank R consists of evaporation / heating, the liquid part of the two-phase mixture being subjected to evaporation and the gas part of the latter being subjected to heating under conditions

  similar to those described previously in the description.

  By way of nonlimiting example, and except in the case of implementation of the process which is the subject of the present invention according to the first variant embodiment in which the densified refrigerated fluid is a refrigerated gas, it exists substantially in the thermally closed enclosure. isolated V, a saturated vapor pressure space constitute "a gaseous sky", as indicated

  commonly in the technique of conditioning liquid gases.

  It is understood, in particular, that the communication of the interior of the thermally insulated closed enclosure V, in the case of implementation of the process object of the present invention according to the first variant, and of the pressure zone saturated vapor or gaseous sky, in the case of

  other methods of implementation previously described in the description,

  then makes it possible to ensure the passage into the gas phase of the fluid in the internal volume of the storage tank R. In all cases, it is indicated that the step consists in admitting, in the thermally insulated enclosure V, the quantity of refrigerated fluid densified QRDF , is a controlled intake of this quantity as a function of the final storage temperature and pressure conditions determined. It is understood, of course, that the admission control is carried out, on the one hand, from the initial temperature, such as ambient temperature, for example, from the interior volume of the thermally insulated closed enclosure V, of the inlet temperature of the densified refrigerant, this inlet temperature not necessarily being equal to the temperature of the densified refrigerant available and, of course, of the free internal volume of

  the aforementioned thermally insulated closed enclosure V.

  The aforementioned controlled intake as a function of the determined final storage temperature and pressure conditions can be carried out at one time, the quantity of densified refrigerated fluid admitted QRDF being calculated in advance, and the intake valve being piloted accordingly,

for example.

  On the contrary, the admission controlled according to the conditions of temperature and final pressure of storage determined above can be

  carried out by successive ad missions of qu antites of densified refrigerant.

  Of course, the successive admissions wind calculated as a function of the aforementioned final storage temperature and pressure conditions determined, but also as a function of the intermediate temperature and pressure conditions achieved by the successive character of the aforementioned admissions. It is indicated that this specific operating mode makes it possible to optimize the storage conditions in the gas phase of the fluid so as, for example, not to exceed the mechanical pressure and / or thermal stresses applied limits either to the thermally insulated closed enclosure V, or even at the reservoir R. Finally, it is indicated, by way of nonlimiting example, that, for an industrial implementation of the process which is the subject of the present invention, the step consists in bringing the compressible fluid outside the storage reservoir , step 1, at a temperature and pressure state lower than the final storage temperature and pressure conditions determined, can be deleted. Under these conditions, the step consists in admitting a determined quantity of the densified refrigerated fluid is advantageously carried out from a reserve or from a cryogenic source, as mentioned

previously in the description.

  The process which is the subject of the present invention, as described above, has the following advantages. The thermally insulated closed enclosure V is thermally decoupled from the reservoir R. which, of course, prevents sudden cooling of the latter and then allows the structure of this reservoir to be made of very light materials, such as the

composite materials.

  The thermally insulated closed enclosure V is designed, designed and equipped in such a way that only the gaseous phase of the admitted densified refrigerated fluid can leave the abovementioned closed enclosure and pass to the internal volume of the

  tank R during the communication step.

  The thermally insulated closed enclosure V being further thermally decoupled from the walls of the reservoir R. the heat exchanges with the external medium are then ensured only through the gas phase fluid contained in the internal volume of the reservoir R. This has the effect of considerably limit the aforementioned heat exchanges and avoid the creation on the reservoir R of cold spots which, inevitably, appear in the case where densified refrigerated fluid is directly poured into the reservoir R. Consequently, the assembly constitutes by the reservoir R. the thermally insulated closed enclosure V and, of course, the densified refrigerant admitted therein, is subjected to slow thermal exchanges, which cause a slow heating of the contents of the thermally insulated closed enclosure V above and, consequently, a slow increase in the pressure within the reservoir R. In general, the process object of the present inv This allows: - rapid filling of the thermally insulated closed enclosure V from a densified refrigerant; - a slow growing internal increase of the whole; a moderate and uniform lowering of the temperature of the external walls of the reservoir R. The thermal machine, thus constituted during the implementation of the process which is the subject of the present invention, thus makes it possible to minimize the thermal and / or mechanical stresses applied to [ together

allowing the implementation.

  In addition, the pressure difference between the thermally insulated closed enclosure V and the tank R can be kept falble, a few bars, the thermally insulated closed enclosure V being able, under these conditions, to be produced and covered with materials. classics, such as a

  metallic material with thin wall thicknesses.

  Finally, the pressure difference between the internal volume of the thermally insulated closed enclosure V and the interior of the tank R has the consequence that the liquefaction temperature of the compressible fluid constituted by a gas in the tank is lower than in the thermally insulated closed enclosure V. The precise operating mode and the condition relating to the specific pressure previously mentioned have the consequence that the compressible fluid, such as a gas contained in the reservoir R. does not risk condensing against the cold external walls of the closed enclosure

thermally insulated.

  A more detailed description of a phase storage device

  gas of a compressible fluid in accordance with the object of the present invention allowing the implementation of the process will now be given in conjunction

  with Figures 2a, 2b and following.

  In general, the gas storage device object of the present invention is designated by 1, the various components or elements of the latter being successively numbered by sets or

  Corresponding functional elements.

  Referring to Figure 2a, the device 1 object of [the invention comprises a storage tank 1O, which is adapted to allow storage in the gaseous phase of the compressible fluid in conditions of temperature and final pressure of storage previously designated in

the description.

  The device 1 further comprises a closed enclosure 20 thermally insulated by means of shims or isolation supports 14, the abovementioned closed enclosure 20, in accordance with a remarkable aspect of the device object of the present invention, being included in the tank of

storage 10.

  An intake circuit 21, 22, 23, 24 ensures the admission into the enclosure 20 of the determined quantity of QRDF fluid supplied

  beforehand in the form of densified refrigerated fluid.

  Finally, circuits 15 and 16 for communicating the space containing the densified refrigerated fluid inside the closed enclosure 20 with the internal volume of the storage tank 10, this internal volume being noted 13, wind expected so to allow a passage of the determined quantity admitted of the densified refrigerated fluid in the gas phase into the internal volume of the reservoir R to be brought about and thus gradually bring the fluid in the gas phase to the final state, temperature and pressure conditions of

  storage determined, previously mentioned in the description. The

reservoir 10 is thus filled.

  As shown in FIG. 2a, the device 1 which is the subject of the invention further comprises circuits for controlling the intake circuits 22, the control circuits being represented in the form of a control switch 220 when, a By way of nonlimiting example, the intake circuit 22 includes an electromechanical valve for example. It also includes control accessories 160 for communication circuits 16, for example, the control accessory 160 which can take the form of a return spring for a pressure relief valve.

  constitute the communication circuit 16, for example.

  It will be understood, in particular, that the control circuit 220 makes it possible to carry out a controlled admission of the densified refrigerant by controlling the control of the opening time of the valve 22, for example, taking into account the conditions of temperature and fluid quantity pressure

densified QRDF to admit.

  Likewise, it is understood that the accessories of S controls 160 of the communication circuits 16, for example, make it possible to carry out a controlled communication of the saturated vapor pressure space, bear the reference 25, of the refrigerated fluid

  densification allowed with the internal volume of the storage tank 10.

  In particular, while the control accessories 160, constituted for example by a return spring of a expansion valve, make it possible to admit the densified refrigerated fluid and, in particular, the saturated vapor thereof by expansion in the internal volume 13 of the reservoir 10, it is also understood, that this all-or-nothing operation, can be added, thanks to a throttling nozzle 15, a substantially continuous communication, but at a much more falble rate, for the pressures

  the saturated vapor of the densified refrigerant.

  In addition, and according to a particular advantageous non-limiting aspect of the device which is the subject of the invention, as shown in FIG. 2a, the controlled admission of the densified refrigerated fluid can be carried out by successive admissions, as a function of the temperature and pressure conditions. final storage determined by means of the valve 22 and, of course, of the control circuit 220. It is understood, in particular, that the control of the circuit 220 makes it possible to carry out one or more admissions with quantities of densified fluid different successive admitted refrigerants, for example, to reach the final storage pressure determined in the internal volume 13

tank 10.

  Different elements or construction features of the device as shown in FIG. 2a, in accordance with the object of the present invention,

will now be given below.

  The reservoir 10 is designed to contain the compressible fluid as

  that a gas under maximum pressure gives PMAX.

  The reservoir 10 and the internal volume 13 of the latter supply a service line 11 equipped with a distribution valve not shown.

in the drawing of Figure 2a.

  The enclosure 20 is equipped with an inlet nozzle 24 and a circuit

  S in communication 15 with the internal volume 13 of the reservoir 10.

  The enclosure 20 is fixed to the reservoir 10 by supports or shims 14 made of thermally insulating material. The intake circuit of the densified refrigerated fluid 23 passes through the reservoir 10 in order to connect the source of densified refrigerated fluid, not shown in FIG. 2a, via the intake valve 22 and the control circuit 220 a the nozzle 24 of the enclosure 20. Of course, the input circuit 23 is thermally insulated from the walls of the reservoir 10 by means of an insulating barrel 12. The thermally insulated closed enclosure 20 is finally equipped with the pressure relief valve 16, which limits the pressure difference between the interior of the enclosure 20 and the interior of the tank to a preset value AP. The preset value of the pressure difference AP

  above may be equal to a few bars.

  The quantity of QRDF densified refrigerant, injected and admitted to filling, is calculated in such a way that once vaporized and brought back to the starting temperature, that is to say the starting temperature of the internal volume 13 of the reservoir. 10, it leads to a fluid pressure in phase

  gas at most equal to the maximum pressure PMAX.

  The thermally insulated closed enclosure 20 is configured to have a volume such that the maximum quantity of densified refrigerated fluid injected cannot completely fill the latter and, consequently, there is

  so always a gaseous sky or space of saturated vapor pressure above

  above the admitted fluid or two-phase mixture, depending on the trotting modes

  covers the process which is the subject of the present invention previously described.

  Of course, the throttle nozzle 15, 17 and the expansion valve 16 wind connected to this gaseous sky or, of course if necessary, to the only internal volume of the thermally insulated closed chamber 20 when the refrigerated fluid

  densified is admitted in the simple refrigerated and densified gas form.

  In all cases, except in the case of the aforementioned covering, the liquid fluid or two-phase mixture is confined in the lower part of the thermally insulated closed enclosure 20 and only the

  gas phase or vapor of saturated pressure can leave the latter.

  During the intake or filling operation of the closed enclosure 20, if the pressure difference between the internal volume of the enclosure 20 and the internal volume of the tank 10 exceeds the preset AP value, the relief valve 16 evacuates saturated steam or refrigerated gas densified from the gaseous sky inside the thermally insulated closed enclosure 20 to

Inside 13 of reservoir 10.

  After the intake stage, the densified refrigerated fluid heats up slowly and the vapor pressure, such as the saturated vapor pressure, increases. The heating takes place by exchanges between the external medium and the reservoir 10, the reservoir 10 and the gas in the gas phase contained in the reservoir 10, the latter gas and the thermally insulated closed enclosure 20 and,

  finally, between the above-mentioned closed enclosure 20 and the densified refrigerated fluid QRDF.

  The increase in pressure of the gaseous sky resulting from the vaporization of the liquid is then evacuated either by the pipe or nozzle with throttle 15, the throttle being intended to maintain a pressure difference between the interior of the closed enclosure 20 and the inside 13 of tank 10

  for the entire duration of the vapor phase of the densified refrigerated fluid.

  As mentioned previously in the description, it follows

  that the vaporization temperature inside the closed enclosure 20 is higher than the liquefaction temperature inside the reservoir 10 and that the gas-phase fluid contained in the internal volume 13 of the reservoir 10 does not thus risk condensing the along the wall of the closed enclosure 20, such a phenomenon possibly leading to an accumulation of the condensed fluid in the bottom of the reservoir 10, the walls of which would then be subjected to stresses

  unacceptable and dangerous thermal conditions.

  So that the expansion of saturated vapor or densified refrigerant, when the latter is in gaseous form, through the throttle nozzle 15 cannot lead to a reliquefaction of the latter, it is advantageous to equip the pipe. nozzle 15 fins promoting heat exchange with the gas phase fluid contained in the internal volume 13 of the reservoir 10. The upper part of the reservoir 10 or is. as shown in FIG. 2a, advantageously places the nozzle at S constriction 15, moreover receives by natural convection the fluid in phase

  hottest gaseous gas contained in the internal volume 13 of the reservoir 10.

  In the case where, depending on the conditions of thermal equilibrium between the closed enclosure 20 and the internal volume of the reservoir 10, the closed enclosure 20 produces more fluid in the gaseous phase than the throttling nozzle 15 can distribute. , 17, the expansion valve 16 evacuates the excess in the internal volume 13 of the reservoir 10. Such a situation can occur either in high heat, or in the event of weak withdrawal by the valve and the pipe.

distribution 1 1.

  At the end of the step of setting in communication and the passage in the gas phase of the fluid in the internal volume 13 of the reservoir 10, then throughout the emptying operation for use of the reservoir 10, the pressures of the reservoir 10 and of the closed enclosure 20 are balanced by transit through

the nozzle has throttle 15, 17.

  The next filling can then start without pressure difference between the internal volume 13 of the reservoir 10 and the internal volume of

the enclosure closed 20.

  An alternative embodiment of the device which is the subject of the present invention and, in particular, of the relative arrangement of the reservoir 10 and of the thermally insulated closed enclosure 20 will now be described in connection

  with Figures 2b and Figures 3a, 3b.

  In general, and in all the modes of implementation of the device which is the subject of the present invention, as shown in FIGS. 2a, 2b and 3a, 3b, for example, the storage tank 10 is formed by a container which is substantially cylindrical of revolution and the closed enclosure 20 is also formed by a substantially cylindrical metallic envelope of revolution. Wile is maintained in any case inside the tank of

  storage 10 through thermally insulating supports.

  Whereas in the case of FIG. 2a, the axis of symmetry of revolution of the storage tank 10 and the axis of symmetry of revolution of the enclosure

  closed 20 wind substantially mixed, in embodiments such as

  represented in FIGS. 2b and 3a, the above-mentioned axes of symmetry of revolution are substantially parallel, but offset, as will be described below. In FIGS. 2b and 3a, it is indicated, of course, that the same

  references represent the same elements as in the case of FIG. 2a.

  In all cases, the intake circuits include the intake valve 22 controlled by the control circuits 220, for example, and the circuits for connecting the space of saturated vapor pressure of the densified refrigerated fluid carry the reference 25 also include the relief or exhaust valve 16 and the nozzle

and constriction 15, 17.

  It will be understood, in particular, that, in the mode of implementation, as shown in FIG. 2b, for example, the device which is the subject of the present invention and, in particular, the reservoir 10 and the closed enclosure 20 can be

  advantageously used horizontally.

  In the case where, in the most general way, the reservoir is manufactured with its inlet and outlet centered on its ends, that is to say on the axis of symmetry of revolution AA 'of FIG. 2a for the reservoir 10 , the offset of the axis of symmetry of revolution BB ′ of the closed enclosure 20 by a guard distance makes it possible to obtain, as illustrated in FIG. 2b, an adapted ratio between the volume of the gaseous sky or space of saturated vapor pressure and the volume of the two-phase mixture or of the liquid phase in the closed enclosure 20 by deviating the axes of

symmetry AA 'and BB' above.

  In general, it is indicated that the closed enclosure 20 subjected to lower pressures than the reservoir 10 can be crossed by incoming and outgoing pipes, such as pipes 24 and 15

  for example, without major difficulty.

  Finally, in the preferential setting mode represented in FIG. 3a, the relative arrangement of the reservoir 10 and of the closed enclosure 20 is specially adapted in order to guard against undesirable effects likely to be caused during the inconsiderate displacement of the assembly, as it will be

described below.

  Indeed, as shown in Figure 3a, if the reservoir 10 is caused to be rolled by turning around the axis of symmetry of revolution M 'or if for example it is impossible to guarantee perfect positioning of the closed enclosure 20 or even if the assembly is subject to and is liable to undergo significant accelerations in a direction orthogonal to the axis of symmetry of revolution M ′, it is advantageous, as shown in FIG. 3a, to mount the closed enclosure 20 thermally insulated so

  be able to rotate around the axis of symmetry of revolution M 'of the reservoir 10.

  In a preferred implementation mode as represented in FIG. 3a and, in particular, when the reservoir 10 further comprises a valve for distributing the fluid stored in the gaseous phase, as represented by the reference 12B in FIG. 3a , The axis of symmetry of revolution M 'of the storage tank 10 and the axis of symmetry BB' of the closed enclosure 20 horizontal winds and shifts of the guard distance,, as shown in FIG. 3a. However, in the embodiment of FIG. 3b, the inlet valve 22 and the distribution valve 110 are then substantially aligned

  on the axis of symmetry of revolution AA 'of the storage tank 10.

  In addition, the closed enclosure 20 is then connected to the inlet valve 22 by means of a payment system 1 2A or rotating joint and mounted for rotation with respect to the axis of symmetry of revolution AA ' of the storage tank. The distribution valve 110 is also advantageously mounted by means of a rotating joint 1 2B or bearing and the closed enclosure 20 is also mounted for rotation with respect to the bearing 12B or rotating joint. Thus, the assembly formed by the closed enclosure 20 and by the QRDF refrigerant admitted into the closed enclosure are mounted in unbalanced rotation by the intermediary of the guard distance and, of course,

  rotational arrangements with respect to bearings or rotary joints 12A, 12B.

  This mode of implementation makes it possible to maintain the horizon of the saturated vapor pressure space or gaseous sky below the orifices of the intake valve 22, orifices formed by the pipe 24, and thus substantially eliminating the risk of direct spreading of the densified refrigerant in the storage tank in the event of impact or displacement

  storage tank 10 uncontrolled.

  Of course, it is indicated that the bearings 12A and 12B or insulating and sealed wind rotary joints. The center of gravity of the closed enclosure assembly 20 + densified refrigerant admitted QRDF being offset from the guard distance 6, the acceleration of gravity or the other accelerations during an inconsiderate displacement make it possible to maintain the liquid at [ 'opposite

  gaseous outlets by the bald effect rd previously mentioned ne.

  Finally, with reference to FIG. 3b, it is indicated that, in the covering of the arrangement as shown in FIGS. 2a, 2b or 3a, the phenomena of expansion of the closed enclosure 20 of the reservoir 10 and of the wind pipes taken into account by the introduction of flexibility zones 201, for example, at the level of the walls 200 of the closed enclosure 20 and by the introduction of metal bellows 230. Expansion joints can also be provided in order to allow games without excessive constraints between the different components. Finally, the wall 100 of the reservoir 10 can be constituted in a conventional manner by a "liner" or metallic envelope 102 and by an external coating 101 made of resin or composite material reinforced with

  KEVLAR or carbon fibers for example.

  The method and the device which are the subject of the present invention appear to be particularly advantageous insofar as the thermally insulated closed enclosure 20 integrated into the internal volume of the reservoir 10 makes it possible to gain space and simplicity of installation and the mass gain of the assembly is significant, insofar as the closed enclosure 20 being subjected to only a small pressure difference of a few bars, the walls thereof can be much thinner than if they had to withstand all the relative conditioning pressure in the tank. Remember that the

  final storage pressure in the tank can be greater than 200 bars.

  In addition, the slow gaseous phase transition of the densified refrigerated fluid makes it possible to provide very gentle pressure build-up ranges for the reservoir 10, even if the filling transfer, that is to say the intake of the densified refrigerated fluid in the closed enclosure 20 thermally insulated, can be performed at high mass flow.

Claims (16)

  1. A method of gas phase storage, in a storage tank, of a compressible fluid under determined conditions of final temperature and pressure of storage, characterized in that it consists in: a) supplying said compressible fluid, outside said storage tank, at a state of temperature and pressure lower than the conditions of final temperature and final pressure of storage determined, in order to obtain a densified refrigerated fluid; b) admitting into a closed thermally insulated enclosure, included in said storage tank, a determined quantity of said densified refrigerated fluid; c) subjecting said determined quantity to said densified refrigerated fluid to a passage in gaseous phase in the volume internal to said storage tank, in order to gradually bring said fluid in gaseous phase to the conditions of final storage temperature and pressure conditions   determined and fill said storage tank.   2. Method according to claim 1, characterized in that said refrigerated fluid is a refrigerated gas, said step of passage into the gas phase in said storage tank consist of heating to said densified refrigerated fluid. 3. Method according to claim 1, characterized in that said densified refrigerated fluid is a refrigerated liquid, said step of passage into gas phase in said storage tank consist of an evaporation to said refrigerant considered.   4. Method according to claim 1, characterized in that said densified refrigerated fluid is a refrigerated solid, said step of passage into gas phase in said storage tank consist of sublimation to said densified refrigerant.   5. Method according to claim 1, characterized in that said densified refrigerated fluid is a two-phase mixture, solid / liquid or liquid / gas, said step of transition to gas phase in said storage tank consist of a fusion / evaporation respectively an evaporation /Warming.   6. Method according to one of claims 1 to 5, characterized in that   that the step consists of admitting, in a thermally insulated enclosure, included in said storage tank, an amount to said densified refrigerated fluid is an intake controlled as a function of the determined final temperature and pressure conditions of storage.   7. Method according to one of claims l to 5, characterized in that   that the said step consists in bringing the led to the compressible fluid, outside of said storage tank, at a state of temperature and of pressure lower than the conditions of final temperature and pressure of determined storage is eliminated, said step consists in admitting a determined quantity to said densified refrigerant being carried out from a reserve or from a cryogenic source.   8. Method according to one of claims 6 or 7, characterized in that   that in that said admission controlled as a function of the final storage temperature and pressure conditions determined is achieved by successive admissions of determined quantities to said densified refrigerated fluid, which makes it possible to optimize the storage conditions in gaseous phase to said fluid. 9. Device for the gaseous phase storage of a compressible fluid, in a storage tank, under determined conditions of final temperature and pressure of storage, characterized in that it comprises at least: - a closed enclosure, thermally insulated , included in said storage tank; means of admission, into said enclosure, of a quantity determined for said fluid previously supplied in the form of densified refrigerated fluid; means of communication of the space containing said densified refrigerated fluid inside said closed enclosure with the volume internal to said storage tank, which makes it possible to cause a passage of said determined quantity to said fluid in gaseous phase in said volume internal and gradually bring said fluid into the gaseous phase at the final storage temperature and pressure conditions   determined to fill said storage tank.   10. Device according to claim 9, characterized in that it further comprises control means desd its ad mission means and said communication means, said control means for carrying out a controlled admission to said fluid densified in liquid phase.   11. Device according to one of claims 9 or 10, characterized in   that said control means also make it possible to effect controlled communication with the saturated vapor pressure space at said   refrigerant densified with the internal volume of said storage tank.   12. Device according to claims 10 and 11, characterized in that   said controlled admission is achieved by successive admissions in function   determined final storage temperature and pressure conditions.   13. Device according to one of claims 9 to 12, characterized in that   that: - said storage tank is formed by a substantially cylindrical container of revolution, - said closed enclosure is formed by a substantially cylindrical metal envelope of revolution, said closed enclosure being maintained inside said storage tank by means of supports thermally insulating.   14. Device according to claim 13, characterized in that the axis of symmetry of revolution to said storage tank and the axis of symmetry of   revolution of said closed enclosure wind substantially parallel.   15. Device according to one of claims 9 to 14, characterized in that   that: - said intake means comprise an intake valve, and said means for bringing the saturated vapor pressure space into communication with said densified refrigerated fluid with the internal volume at said storage tank comprise an exhaust valve and a nozzle throttling.   16. Device according to claims 14 and 15, characterized in that   qu e, led à reservoir further comprising a valve for distributing the fluid stored in the gaseous phase, - the axis of symmetry of revolution to said storage tank and the axis of symmetry of said horizontal closed enclosure, and guard distance decals; - Said inlet valve and said distribution valve wind substantially aligned on said axis of symmetry of revolution to said storage tank; - Said closed enclosure is connected to said inlet valve by means of a rotary joint and mounted for rotation with respect to the axis of symmetry of revolution of the storage tank and of said distribution valve, I assembly formed by said closed enclosure and by the densified refrigerant admitted into said closed enclosure being mounted in unbalanced rotation by the intermediary of said guard distance, which makes it possible to maintain the horizon of the space of saturated vapor pressure in -deca of the orifices of the intake valve and substantially eliminate the risk of direct spreading to said densified refrigerant in said storage tank in the event of impact or