DEVICE FOR THE STORAGE AND DELIVERY OF CRYOGENS FLUID, VEHICLE AND CORRESPONDING PROCEDURE

Description

[0001] The invention relates to a device for storing and supplying cryogenic fluid, a vehicle comprising such a device and a corresponding method.

[0002] The invention relates more particularly to a device for storing and supplying cryogenic fluid, in particular an on-board device for storing and supplying liquefied hydrogen, comprising a cryogenic tank for storing liquefied fluid, a withdrawal circuit, the device comprising a system for pressurizing the tank comprising a pressurizing pipe having two ends connected respectively to the upper and lower parts of the tank, a vaporization heat exchanger and a set of valve(s) configured to allow the withdrawal of liquid from the tank, its reheating in the vaporization heat exchanger and its reintroduction into the tank.

[0003] The pressurization of cryogenic tanks, particularly liquefied hydrogen semi-trailers, is generally carried out by drawing off liquid, vaporizing at the low point, and re-injecting the heated gas at the high point of the tank by the thermosiphon phenomenon.

[0004] This pressurization increases the internal energy of the system and leads to an increase in the saturation pressure of the liquid (and its temperature). This can be problematic in applications where the customer specifies a maximum delivery temperature of the fluid.

[0005] The temperature of the gas injected into the tank is an important optimization parameter. To limit the energy input per unit of pressurization, it is advantageous to inject the gas at the highest possible temperature and to ensure a strong vertical thermal gradient in the tank (stratification) to keep the liquid in the lower part at the coldest possible temperature. An example of a device is disclosed in document EP 3 690 303.

[0006] An aim of the present invention is to overcome all or part of the drawbacks of the prior art noted above.

[0007] To this end, the device according to the invention, moreover in accordance with the generic definition given in the preamble above, is essentially characterized in that the reservoir pressurization system is configured to withdraw a determined volume of fluid from the reservoir, store and isolate this volume in the vaporization heat exchanger until the volume of fluid reaches determined temperature and / or pressure conditions before reinjecting this volume of fluid into the reservoir, the pressurization pipe comprising a member for limiting the flow rate and / or the pressure of the volume of reinjected fluid.

[0008] Furthermore, embodiments of the invention may include one or more of the following features: the set of valve(s) of the pressurization line comprises two isolation valves arranged on either side of the vaporization heat exchanger, the flow and / or pressure limiting member is arranged in parallel with the isolation valves located between the vaporization heat exchanger and the upper end of the tank, the flow and / or pressure limiting member comprises a pressure regulating valve at a fixed or adjustable determined level, the flow and / or pressure limiting member is constituted by one of the two isolation valves and / or a valve separate from the two isolation valves, the pressurization line comprises a buffer storage communicating with an outlet of the heat exchanger and configured to accommodate a portion of the volume of fluid, the buffer storage is connected on the one hand upstream of the isolation valve located between the vaporization heat exchanger and the upper end of the tank and,on the other hand, downstream of the vaporization heat exchanger, the pressurization pipe comprises a pressure-sensitive safety valve having a first end communicating with an outlet of the vaporization heat exchanger and a second discharge end connected to a discharge zone such as the atmosphere or the tank, the pressurization pipe comprises two vaporization heat exchangers arranged in parallel, the device comprises a programmable electronic controller configured to control all or part of the set of valves and possibly the flow and / or pressure limiting member, for example as a function of the pressure in the tank.

[0009] The invention also relates to a vehicle, in particular a truck transporting a device according to any one of the characteristics above or below.

[0010] The invention also relates to a method for regulating the pressure in a cryogenic tank of such a cryogenic fluid storage and supply device or such a vehicle, comprising a step of withdrawing a determined volume of fluid from the tank, a step of storing and isolating this volume in the vaporization heat exchanger and, when the volume of fluid reaches a predetermined temperature and / or pressure by spontaneous heating, a step of reinjecting this volume of fluid into the tank.

[0011] The invention may also relate to any alternative device or method comprising any combination of the above or below features within the scope of the claims.

[0012] Other features and advantages will appear on reading the description below, made with reference to the figures in which: [ Fig.1 ] represents a schematic and partial sectional view illustrating a first example of structure and operation of a device according to the invention, [ Fig.2 ] represents a schematic and partial sectional view illustrating a vehicle equipped with a second example of structure and operation of a device according to the invention, [ Fig.3 ] represents a schematic and partial sectional view illustrating a third example of structure and operation of a device according to the invention.

[0013] The illustrated cryogenic fluid storage and supply device 1 may be an on-board liquefied hydrogen storage and supply device.

[0014] The device 1 comprises a cryogenic tank 2 for storing liquefied fluid (for example a double-walled vacuum-insulated tank) and a withdrawal circuit 10. In the schematic example shown, the withdrawal circuit comprises a liquid withdrawal pipe but, of course, as a variant or in combination, a gas withdrawal pipe can be envisaged. The same applies to filling (same circuit as for withdrawal or separate circuit).

[0015] The device 1 further comprises a system for pressurizing the tank 2 provided with a pressurization pipe 3 having two ends connected respectively to the upper and lower parts of the tank 2. This pressurization pipe 3 comprises a vaporization heat exchanger 4 and a set of valve(s) 5, 6 configured to allow the withdrawal of liquid from the tank 2, its reheating in the vaporization heat exchanger 4 and its reintroduction into the tank 2.

[0016] According to an advantageous feature, instead of heating via thermosiphon-type circulation, the pressurization system of the tank 2 is configured to withdraw a determined volume of fluid from the tank 2, store and isolate this volume in the vaporization heat exchanger 4 until the volume of fluid reaches determined temperature and / or pressure conditions before reinjecting this volume of fluid into the tank 2. In addition, the pressurization pipe 3 comprises a member 7 for limiting the flow rate and / or the pressure of the volume of reinjected fluid.

[0017] For example, the trapped fluid is reinjected into tank 2 when its pressure is increased by 10 bar compared to its initial conditions and / or when its pressure level reaches 25 bar and / or when the temperature has been increased by 50 degrees and / or when its temperature reaches 100 degrees Kelvin.

[0018] That is to say that the pressurization system ensures thermal compression of the fluid in the vaporization heat exchanger 4 to pressurize the tank 2 while limiting the energy input. The injection of the heated fluid can be carried out in the gaseous airspace of the tank 2 via a nozzle limiting the temperature de-stratification of the fluid in the tank.

[0019] This makes it possible to maximize the pressurization of tank 2 by limiting the energy input into it.

[0020] This allows a better result than known solutions which only vaporize the fluid and do not allow the re-injected cold fluid to be heated (in known systems a large quantity of fluid must be vaporized before pressurizing the tank 2).

[0021] The set of valve(s) 5, 6 of the pressurization pipe (3) may comprise for this purpose two isolation valves arranged on either side of the vaporization heat exchanger 4.

[0022] This self-pressurization can be achieved by filling the vaporization heat exchanger 4 with liquid by opening the two corresponding valves 5, 6, then closing them. After the exchanger 4 (or the fluid it contains) has reached a predetermined temperature (for example typically less than 30-40K), the heated fluid will increase the pressure in the heat exchanger 4. When this pressure reaches a target value (which can be predetermined by calculation or by adjustment), the fluid can be reinjected into the tank 2.

[0023] The flow and / or pressure limiting member 7 may be arranged in parallel with the isolation valve 6 located between the vaporization heat exchanger 4 and the upper end of the tank 2. In addition, this flow and / or pressure limiting member 7 may comprise or consist of a pressure regulating valve at a fixed or adjustable determined level. This regulating valve 7 may for example be configured to open (automatically, for example passively or in a controlled manner) when the pressure in the vaporization exchanger 4 reaches the target value. This regulating valve 7 will then send the hot fluid to the tank 2.

[0024] The isolation valve 6 can also be opened or controlled if necessary.

[0025] The pressurization line 3 preferably comprises a pressure-sensitive safety valve 8 having a first end communicating with at least one of: the upper end of the tank 2, an outlet of the vaporization heat exchanger 4 and a second discharge end connected to a discharge zone such as the atmosphere around the device 1 or the gaseous headspace of the tank 2.

[0026] This valve protects the system from overpressure which could damage the vaporization heat exchanger 4.

[0027] As illustrated in the example of the [ Fig.2 ], the device 1 can be mounted on a vehicle, in particular a semi-trailer.

[0028] As also illustrated, an additional buffer storage 18 may be provided in the pipe 3. This storage forms a capacity of reduced volume compared to the volume of the tank 2 and may communicate with an outlet of the heat exchanger 4. This storage is configured to accommodate a portion of the volume of fluid which is trapped (to increase this volume beyond the volume of the heat exchanger 4 alone).

[0029] For example, the buffer storage 18 is connected upstream to the isolation valve 6 located between the vaporization heat exchanger 4 and the upper end of the tank 2. This therefore makes it possible to increase the volume of available pressurized gas.

[0030] Note that, as a variant or in combination, it is possible to envisage a device with two (or more) vaporization heat exchangers 4 (for example two exchangers of equivalent power or volume, for example twice less powerful respectively than in the variant with a single vaporization heat exchanger 4). This can allow sequential use of the two heat exchangers 4 in parallel and thus increase the frequency of the depressurization cycles towards the tank. This can also improve the modularity of the pressurization system, for example by using only one of the two exchangers for the pressurizations of a first level and both exchangers simultaneously for the higher pressurizations (in particular when the liquid level is relatively low in the tank 2). This variant also makes it possible to smooth the hot fluid reinjection flow rates.Indeed, a high flow rate of hot fluid can disturb the temperature stratification of the gaseous atmosphere of reservoir 2.

[0031] All or part of the set of valves and possibly the flow and / or pressure limiting member 7 can be controlled by a programmable electronic controller 9 comprising a microprocessor and configured for this purpose.

[0032] Note that in a possible variant embodiment, the flow or pressure limiting member 7 illustrated may consist of the isolation valve 6 interposed between the outlet of the vaporization heat exchanger 4 and the upper part of the tank 2. For example, this valve may have a progressive opening and its opening may be controlled as a function of the pressure in the vaporization heat exchanger 4. In this case, as illustrated in [ Fig.3 ], the separate additional flow limiting organ 7 shown in [ Fig.1] et [Fig.2 ] can be omitted.

[0033] The invention, while being of simple structure and inexpensive, allows efficient pressurization and optimizes the use of the pressurization heater.

Claims

1. Device for storing and supplying cryogenic fluid, notably an on-board device for storing and supplying liquefied hydrogen, comprising a cryogenic tank (2) for storing liquefied fluid, a withdrawal circuit (10), the device (1) comprising a system for pressurizing the tank (2) comprising a pressurization line (3) having two ends respectively connected to the upper and lower parts of the tank (2), a vaporization heat exchanger (4) and a set of valve(s) (5, 6) configured to allow liquid to be withdrawn from the tank (2) and comprising an isolation valve (6) situated between the vaporization heat exchanger (4) and the upper end of the tank (2), to be heated in the vaporization heat exchanger (4) and to be reintroduced into the tank (2), the system for pressurizing the tank (2) being configured to withdraw a determined volume of fluid from the tank (2), store and isolate this volume in the vaporization heat exchanger (4) until the volume of fluid reaches determined temperature and / or pressure conditions prior to reinjection of this volume of fluid into the tank (2), the pressurization line (3) comprising an element (7, 6) for limiting the flow rate and / or the pressure of the reinjected volume of fluid, characterized in that the element (7) for limiting the flow rate and / or the pressure is disposed in parallel with the isolation valve (6) situated between the vaporization heat exchanger (4) and the upper end of the tank (2).

2. Device according to Claim 1, characterized in that the set of valve(s) (5, 6) of the pressurization line (3) comprises two isolation valves disposed on either side of the vaporization heat exchanger (4).

3. Device according to either one of Claims 1 and 2, characterized in that the element (7) for limiting the flow rate and / or the pressure comprises a valve for regulating pressure to a determined level that is fixed or adjustable.

4. Device according to Claims 2 and 3 considered in combination, characterized in that the element for limiting the flow rate and / or the pressure is constituted by one (6) of the two isolation valves and / or a valve (7) separate from the two isolation valves (5, 6).

5. Device according to any one of Claims 1 to 4, characterized in that the pressurization line (3) comprises a buffer storage reservoir (18) that communicates with an outlet of the heat exchanger (4) and that is configured to accommodate part of the volume of fluid.

6. Device according to Claim 5, characterized in that the buffer storage reservoir (18) is attached, for the one part, upstream of the isolation valve (6) situated between the vaporization heat exchanger (4) and the upper end of the tank (2), and, for the other part, downstream of the vaporization heat exchanger (4).

7. Device according to any one of Claims 1 to 6, characterized in that the pressurization line (3) comprises a pressure-sensitive safety valve (8) having a first end communicating with an outlet of the vaporization heat exchanger (4) and a second, discharge end connected to a discharge zone such as the atmosphere or the tank (2).

8. Device according to any one of Claims 1 to 7, characterized in that the pressurization line (3) comprises two vaporization heat exchangers (4) disposed in parallel.

9. Device according to any one of Claims 1 to 8, characterized in that it comprises a programmable electronic controller (9) configured to control all or part of the set of valves (5, 6) and possibly the element (6, 7) for limiting the flow rate and / or the pressure, for example as a function of the pressure in the tank (2).

10. Vehicle, notably a truck, transporting a device (1) according to any one of the preceding claims.

11. Method for regulating the pressure in a cryogenic tank of a device for storing and supplying cryogenic fluid in accordance with any one of Claims 1 to 9 or of a vehicle according to Claim 10, comprising a step of withdrawing a determined volume of fluid from the tank (2), a step of storing and of isolating this volume in the vaporization heat exchanger (4) and, when the volume of fluid reaches, by spontaneous heating, a predetermined temperature and / or a predetermined pressure, a step of re-injecting this volume of fluid into the tank (2).