Double-walled storage tank with integrated heating element

Abstract

A storage container for a medium, in particular for liquefied gases, is described, comprising an outer container 10, an inner container 11, insulation 13 arranged between the inner and outer containers, a filling line 3 leading into the inner container for the medium to be stored, and a discharge line 14 leading out of the inner container for the medium to be stored. According to the invention, means for heating 15 of the inner container are associated with the inner container.

Description

[0001] The invention relates to a storage container for a medium, in particular for liquefied gases, comprising an outer container, an inner container, insulation arranged between the inner and outer containers, a filling line leading into the inner container for the medium to be stored, and a discharge line leading out of the inner container for the medium to be stored.

[0002] Storage containers of this type are known in a wide variety of designs. They are used in particular for storing liquefied gases, such as hydrogen, nitrogen, oxygen, etc.

[0003] Furthermore, such storage containers are also used to arrange cryogenic hydrogen pumps in them, which compress the medium contained in the storage container, preferably hydrogen, to a desired pressure between 1 and 18 barg (low-pressure pumps) or 1 and 1000 barg (high-pressure pumps).

[0004] The insulation between the inner and outer containers is preferably designed as vacuum insulation, in particular in the form of so-called multi-layer insulation. Alternatively, perlite or glass bubble fillings are used, or no filling materials are used at all.

[0005] In the event of a defect or maintenance of such storage containers or the cryogenic (hydrogen) pump located within them, the storage container must be emptied to gain access to the inner container and the pump located within it. This requires warming the inner container, preferably to ambient temperature, and possibly cleaning or flushing it. Due to the vacuum insulation described above, this warming process using heat from the environment takes several days. Such long maintenance times are unacceptable, especially when it comes to the maintenance or repair of the cryogenic hydrogen pump.

[0006] Currently, the heating of the inner container is accelerated by purging it with warm gas, preferably hydrogen or nitrogen. While this achieves acceptable heating times, it requires additional piping, an external gas supply, and procedural and safety protocols. Therefore, this solution is comparatively expensive, complicated, and impractical.

[0007] The object of the present invention is to provide a storage container of the generic type which enables a comparatively quick and uncomplicated heating of the inner container.

[0008] To solve this problem, a storage container of the generic type is proposed, characterized in that means for heating the inner container are assigned to the inner container.

[0009] In this case, the means for heating the inner container are advantageously designed as at least one electric heating element, which is arranged on the inside and / or the outside of the inner container.

[0010] The invention now makes it possible to generate the heat required for warming the inner container directly at the required location within the storage container. This is achieved in particular by using one or more electric heating coils that are attached directly to the inside and / or outside of the inner container.

[0011] Further developing the storage container according to the invention, it is proposed that the inner container has at least one temperature sensor designed for measuring the temperature of the inner container.

[0012] This design of the storage container according to the invention allows for controlled heating of the inner container or the medium stored therein.

[0013] The storage container according to the invention, as well as further advantageous embodiments thereof, are described below with reference to the one described in the Figure depicted

[0014] An exemplary embodiment is explained in more detail below. The figure shows a schematic cross-sectional view through a storage container with a cryogenic hydrogen pump arranged inside it.

[0015] The storage container shown in the figure is used to hold liquid hydrogen. It has an outer container 10 and an inner container 11, between which a vacuum insulation 13 is arranged. The inner container is sealed to the environment by a sealing flange 12. Liquid hydrogen 3 is supplied to the inner container 11 via a filling line 2. Gaseous hydrogen is withdrawn via the withdrawal line 14. If the storage container according to the invention is used exclusively for storing a medium, the withdrawal line 14 is preferably arranged such that withdrawal of liquid medium is also possible. Such storage containers can, in principle, also have several filling and / or withdrawal lines. Advantageously, the discharge line 14 has a valve-operated outlet for discharging the heated medium to a safe venting point, preferably a chimney.

[0016] The cryogenic hydrogen pump located in the storage container has several actuators 1, a piston rod 7, and the associated draw tube sleeve 8 and seal 9 via the end flange 12, located outside the storage container, and a piston chamber 5. During operation of the hydrogen pump, this chamber is completely immersed in the liquid hydrogen. The liquid hydrogen pumped by the hydrogen pump is discharged from the inner container 11 via the discharge line 4.

[0017] According to the invention, the inner container 11 is provided with means for heating it. In the embodiment of the storage container according to the invention shown in the figure, these means for heating the inner container are designed as one or more electric heating coils 15 arranged on the outside of the inner container 11. Alternatively or additionally, these electric heating coils 15 can be provided on the inside of the inner container 11. Advantageously, the heating coils 15 are arranged such that they are in direct contact with the outside of the inner container 11 over as large an area as possible. Furthermore, it is important to ensure that the means for heating the inner container provided according to the invention are designed for use in a vacuum and at extremely low temperatures. Any necessaryThe external power supply 6 to be provided for the heating coil(s) 15 must be sealed accordingly when passing through the outer container 10 and the vacuum insulation 13.

[0018] Furthermore, at least one temperature sensor 16 is advantageously provided, which is designed for measuring the temperature of the inner container 11 or its storage space.

[0019] If the storage container according to the invention, or its inner container 11, needs to be heated, the supply of hydrogen via the filling line 2 is stopped. The electric heating coils 15 are then activated, and the heating process begins. The process is monitored by means of the temperature sensor 16. Due to the heating process, the liquid hydrogen 3 evaporates and escapes from the inner container 11 via the discharge line 14. Once the desired inner container temperature is reached, the electric heating coils 15 are deactivated, and maintenance or repair work on the inner container 11 and / or the hydrogen pump can be carried out.

[0020] The storage container according to the invention thus enables a comparatively quick and uncomplicated heating of the inner container. The equipment required for this is comparatively low, which is why the invention is particularly advantageous for storage containers where short operating times are essential.

Claims

1. Storage container for a medium, in particular for liquefied gases, comprising: - an outer container (10), - an inner container (11), - insulation (13) arranged between the inner and outer containers, - a filling line (2) leading into the inner container (11) for the medium to be stored, and - a discharge line (14) leading out of the inner container (11) for the medium to be stored. characterized by the fact that The inner container (11) is assigned means for heating the inner container (15).

2. Storage container according to claim 1, characterized by the fact that the means for heating (15) the inner container (11) are designed as at least one electric heating element, preferably in the form of a heating coil, which is arranged on the inside and / or the outside of the inner container (11).

3. Storage container according to claim 1 or 2, characterized by the fact thatthe inner container (11) has at least one temperature sensor (16) designed to measure the temperature of the inner container (11).

4. Storage container according to one of the preceding claims, wherein the storage container serves to store liquid hydrogen, characterized by the fact that a cryogenic hydrogen pump is assigned to the inner container (11), wherein at least the piston chamber (5) of the hydrogen pump is arranged such that it is immersed in the liquid hydrogen during pumping operation.

5. Storage container according to claim 4, characterized by the fact that the hydrogen pump associated with the inner container (11) has a termination flange (12) to the outer container (10), a draw tube sleeve (8) and a seal (9).

6. Storage container according to one of the preceding claims, characterized by the fact that The insulation is designed as vacuum insulation.

7. Storage container according to one of the preceding claims, characterized by the fact thatthe cable for the electrical voltage supply (6) of the heating element (15) is guided through the wall of the outer container (10) by means of a vacuum feedthrough.

8. Storage container according to one of the preceding claims, characterized by the fact that the discharge line (14) has a valve-operated outlet for the discharge of the heated medium to a safe discharge point, preferably a chimney pipe.

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