RU2812529C1 - Tank for stationary storage of cryogenic fluids - Google Patents

Abstract

FIELD: storage tanks.

SUBSTANCE: invention relates to a tank for storing cryogenic fluids, for example liquefied natural gas, made in the form of a hollow vessel having walls. According to the invention, the walls of the vessel have main stiffening ribs located along the entire internal surface of the vessel, and additional stiffening ribs, also located along the entire internal surface of the vessel between the main stiffening ribs, whereas the additional stiffening ribs are smaller in size than the main stiffening ribs, and all ribs rigidities form a power cellular structure of the walls of the vessel. The walls and all stiffening ribs are made of a composite material, which is a structure made of inorganic fibre, or textile materials made of such fibre, impregnated with a hardening binder. The vessel is covered with a heat-insulating shell, installed using an adhesive method.

EFFECT: creating a lightweight and durable tank for storing cryogenic fluids, which does not use a metal or metallized gas-tight membrane.

6 cl, 2 dwg

Description

Field of technology to which the invention relates

The present invention relates to tanks for storing cryogenic fluids, for example, liquefied natural gas, made in the form of a hollow container having walls.

State of the art

Currently, there are many tanks for stationary storage of cryogenic fluids. A reservoir for stationary storage of cryogenic fluids is known from the prior art, made in the form of a hollow container with walls, see the description of RF patent No. 2379577, published in 2010.

This device is the closest in technical essence to the claimed invention and is taken as a prototype. Thus, the device proposed in this description will be described in terms of differences from the prototype.

The disadvantage of the prototype is that the walls of the container are made of metal. This causes the tank to be overweight. In addition, ensuring its tightness is a complex, time-consuming and expensive task. Another disadvantage is that the interface between the metal container and thermal insulation has a large difference in the coefficients of thermal linear expansion. Therefore, complex solutions are used to compensate for the difference in thermal “breathing” of different layers of structures.

Disclosure of the Invention

The present invention primarily aims to provide a permanent storage tank for cryogenic fluids, configured as a hollow container having walls that allow the creation of a lightweight and durable cryogenic fluid storage tank that does not use a metal or metallized gas-tight membrane, which is the technical task set.

To achieve this goal, the walls of the container have main stiffening ribs located along the entire internal surface of the container, and additional stiffening ribs also located along the entire internal surface of the container between the main stiffening ribs, while the additional stiffening ribs are smaller in size than the main stiffening ribs, and all stiffening ribs form a power cellular structure of the walls of the container, in addition, the walls and all stiffening ribs are made of a composite material, which is a structure made of inorganic fiber, or textile materials from such fiber, impregnated with a hardening binder, while the container is covered with a heat-insulating shell installed with an adhesive way.

Thanks to such advantageous characteristics, it becomes possible to create a tank without metal parts. Since all known solutions have an internal metal container (barrier) that acts as a gas-tight membrane, and ensuring its tightness is a complex, time-consuming, expensive task, an important advantage of the proposed solution is that there is simply no such problem. The composite membrane is immediately covered with a layer of thermal insulation.

The second difficulty of all existing solutions is the combination of a metal container and thermal insulation. They have a large difference in the coefficients of thermal linear expansion. Therefore, complex solutions are used to compensate for the difference in thermal “breathing” of different layers of structures. In our case, the difference in CTLR is very small and is compensated by the plasticity of the glued layer of heat-insulating foam.

In this case, the strength of the tank is ensured by the indicated stiffeners. The surfaces of the tank perceive static loads from stored liquefied gases, from the pressure of their vapors on the edge of the container, from installation and transport loads, from the weight of the container itself.

From a technical point of view, it is significant that for the first time a reservoir made of a composite material is proposed, which provides gas-tightness. This allows you to create containers without metal internal gas-tight shells. This radically simplifies their design, making them lighter and cheaper.

There is a possible variant of the invention in which carbon fiber-based material is used as the composite material of the container.

Thanks to such advantageous characteristics, a specific option for manufacturing a tank based on carbon fiber becomes possible. Due to the fact that carbon fiber is a material consisting of thin threads with a diameter of 5 to 10 microns, formed mainly by carbon atoms, and the carbon atoms are combined into microscopic crystals aligned parallel to each other; the alignment of the crystals gives the fiber greater tensile strength. Carbon fibers are characterized by high tensile strength, low specific gravity, low coefficient of thermal expansion and chemical inertness.

There is another possible embodiment of the invention, in which a fiberglass-based composite material is used as the composite material of the container.

Thanks to such advantageous characteristics, it becomes possible to manufacture a concrete tank based on fiberglass. Glass fiber has roughly comparable mechanical properties to other fibers such as polymers and carbon fiber. Although not as stiff as carbon fiber, it is much cheaper when used in composites. Glass fiber reinforced composites are used in the marine and pipeline industries due to their good environmental resistance, better resistance to impact damage, high specific strength and stiffness.

There is also a possible variant of the invention, in which epoxy resin is chosen as the hardening binder.

Thanks to such advantageous characteristics, a specific variant of the hardening binder becomes possible. In this case, carbon fiber and epoxy resin form carbon fiber plastic, which is used as a structural material in various fields: from aircraft construction to automobile construction, and a composite based on epoxy resins is used in the fastening bolts of earth-to-space rockets, which emphasizes the strength of the connection.

There is another possible variant of the invention, in which a polyester resin is selected as the hardening binder.

These advantageous characteristics create the possibility of a specific curing binder option, such as polyester resin, which is generally less expensive than epoxy.

Finally, there is another possible variant of the invention, in which the walls and all stiffening ribs are made of a composite material by vacuum infusion and/or pultrusion.

Thanks to such advantageous characteristics, a specific embodiment of the invention becomes possible.

Thus, a tank for stationary storage of cryogenic fluids is proposed made of a composite material based on carbon fiber, glass fiber or other fibers, without metal or metallized gas-tight barriers, with a heat-insulating shell made of heat-insulating material(s), for example: polyurethane foam, installed by adhesive method, without welding and mechanical fastening methods, without metal technological elements remaining in the structure after manufacturing. It also does not have concrete or steel frame and shell building elements in its design.

Proposed tank compared to existing designs:

• not subject to corrosion;

• can be designed and manufactured for overpressure up to 10 Bar or more;

• easier;

• faster in construction (can be assembled on site from fully prefabricated elements);

• cheaper.

Brief description of drawings

Other features and advantages of the present invention will clearly appear from the description given below by way of illustration and non-limitation, with reference to the accompanying drawings, in which:

- figure 1 shows the external interior of a tank for stationary storage of cryogenic fluids, according to the invention,

- Figure 2 shows a section through the wall of a tank container for stationary storage of cryogenic fluids, according to the invention.

The figures indicate:

1 - walls,

2 - main stiffeners,

3 - additional stiffeners,

4 - composite shell,

5 - heat-insulating shell

6 - adhesive layer,

7 - layer with surface protection.

According to the figures, a reservoir for stationary storage of cryogenic fluids, made in the form of a hollow container, has walls 1 of the container, which have main stiffening ribs 2 located along the entire inner surface of the container, and additional stiffening ribs 3, also located along the entire inner surface of the container between the main ones stiffening ribs.

Additional stiffening ribs 3 are smaller in size than the main stiffening ribs 2. All stiffening ribs form a power cellular structure of the container walls. The walls and all stiffeners are made of composite material 4, which is a fiber structure impregnated with a hardening binder. The composite material used for the container is predominantly a material based on carbon fiber or glass fiber. But a composite based on basalt or other fiber can also be used.

In general, the container is covered with a heat-insulating shell 5, installed by adhesive. An epoxy resin or a polyester resin can be selected as the curing binder.

The dimensions of ribs 2 and 3 and the distances between them are determined by mathematical modeling of the forces affecting the container throughout its life cycle.

The heat-insulating shell is a continuous, gap-free layer of thermal insulation glued to the surface of the container. The thickness of the thermal insulation layer is determined by mathematical thermophysical modeling of storage of a cryogenic fluid in a container.

Carrying out the invention

The tank for stationary storage of cryogenic fluids operates in a standard manner, just like other tanks.

Industrial applicability

A tank for stationary storage of cryogenic fluids can be implemented by a specialist in practice and, when implemented, ensures the implementation of the stated purpose, which allows us to conclude that it meets the criterion of “industrial applicability” for the invention.

In accordance with the proposed invention, calculations of the strength of a tank for stationary storage of cryogenic fluids were carried out.

Calculations showed that he:

- allows you to vary the thickness of the tank wall and the size of the stiffeners, while obtaining the ability to store any volume of cryogenic fluid at any excess pressure.

Thus, the stated technical result is achieved: the creation of a lightweight and durable tank for storing cryogenic fluids, which does not use a metal or metallized gas-tight membrane.

Claims (6)

1. A reservoir for stationary storage of cryogenic fluids, made in the form of a hollow container having walls, characterized in that the walls of the container have main stiffening ribs located along the entire internal surface of the container, and additional stiffening ribs also located along the entire internal surface of the container between main stiffening ribs, while additional stiffening ribs are smaller in size than the main stiffening ribs, and all stiffening ribs form a power cellular structure of the walls of the container, in addition, the walls and all stiffening ribs are made of a composite material, which is a structure made of inorganic fiber, or textile materials made from such fiber, impregnated with a hardening binder, while the container is covered with a heat-insulating shell, installed using the adhesive method. 2. The reservoir according to claim 1, characterized in that Carbon fiber-based material is used as a composite material for the container. 3. The tank according to claim 1, characterized in that a fiberglass-based composite material is used as the composite material of the tank. 4. The reservoir according to claim 1, characterized in that epoxy resin is selected as the hardening binder. 5. The reservoir according to claim 1, characterized in that polyester resin is selected as the hardening binder. 6. The tank according to claim 1, characterized in that the walls and all stiffening ribs are made of composite material using the method of vacuum infusion and/or pultrusion.