CN1333198C - High vacuum heat insulation low temperature liquefied gas storage tank - Google Patents

Abstract

The invention provides a high-vacuum multi-layer heat-insulated low-temperature liquefied gas storage tank, which includes a frame and a tank body. The tank body is composed of an outer shell, an inner tank, and a combined supporting structure connecting the outer shell and the inner tank. The combined supporting structure is only provided with the tank body Between the inner and outer heads at both ends, it can bear radial load and axial load, the heat transfer area of the inner tank and the outer shell is small, the bearing capacity of the supporting structure is large, and the effective loading volume of the inner tank is large.

Description

High vacuum insulation cryogenic liquefied gas storage tank

technical field

The present invention relates to a low-temperature liquefied gas storage and transportation equipment, and more specifically relates to a high-vacuum heat-insulated low-temperature liquefied gas storage tank, which may be a tank truck or a tank container suitable for efficiently transporting low-temperature liquefied gas. The present invention realizes that the impact force and the temperature change of the carrier medium that the low-temperature liquefied gas storage and transportation equipment bears during the operation process meet the requirements of the low-temperature liquefied gas The requirements for storage and transportation, and the vacuum layer between the inner tank and the outer cylinder of the cryogenic container is the thinnest, and finally the loading rate of the cryogenic liquefied gas is maximized. The invention belongs to the field of cryogenic engineering and cryogenic technology.

Background technique

The vacuum-powder insulation technology, born in 1909, has greatly improved the performance of cryogenic storage tanks. By the end of the 1930s, vacuum-powder insulation had been widely used in the entire low-temperature field represented by air separation and liquefaction. In the early 1950s, high-vacuum multilayer insulation appeared, which was an important development in the history of low-temperature insulation. Especially in the late 1950s, due to the development of space technology, the amount of liquid hydrogen and liquid helium increased sharply, greatly Promoted the research and application of high-vacuum multi-layer insulation, among which tank trucks and tank containers for transporting cryogenic liquefied gases are the main application products.

In the field of cryogenic technology, cryogenic liquefied gases refer to gases that exist in liquid form below -160°C, such as liquid oxygen, liquid nitrogen, liquid argon, liquid hydrogen, liquid helium, liquid methane, and LNG. Since the liquid volume of this type of gas is about 600 times smaller than that of the gaseous state, it is often stored and transported in a liquid state. Equipment for transporting cryogenic liquefied gas, including tank trucks and tank containers, etc. The tank body is a double-layer structure, and there is a vacuum layer between the inner tank and the outer shell. The inner tank and the outer shell are connected by a supporting structure. Due to the requirements of transportation regulations, storage and transportation equipment ( Tank trucks and tank containers, etc.) have a maximum external dimension limit. In the case of limiting the maximum external dimensions, the effective volume of the medium that can be shipped by storage and transportation equipment (tank trucks and tank containers, etc.) depends on the thickness of the vacuum layer.

Vacuum-powder insulation tank trucks and tank containers are relatively common low-temperature transportation equipment in China at present. The heat insulation is achieved by adding perlite to the vacuum layer between the shell and the inner tank. In order to achieve a satisfactory heat insulation effect, the vacuum layer is more Thick, usually the thickness of the vacuum layer is 200~300 mm, therefore, the effective volume of the actual shipment is sacrificed; plus the deposition of perlite during transportation, the heat insulation performance of the transportation equipment is affected. Therefore, the application of high-vacuum multi-layer insulation technology in transportation equipment has been promoted. Utility models ZL00216678.X, ZL00249960.6, and ZL01272605.2 are examples of the application of high-vacuum multilayer insulation technology in transportation equipment.

High-vacuum multi-layer heat insulation storage and transportation equipment (tank trucks and tank containers, etc.) is to wrap heat insulation materials on the outer surface of the tank inner liner, and form a heat insulation layer by vacuuming the vacuum interlayer containing multi-layer heat insulation materials. The vacuum interlayer The thinner the tank, the more transport medium is loaded on the tank; but the thinner the insulation layer, the more difficult it is to arrange the supporting structure connecting the inner tank and the outer shell, the thinner the thermal insulation layer, the lower the high vacuum, and the more heat transfer between the inner tank and the outer shell. The greater the heat loss of low-temperature liquefied gas, the current multi-layer insulation technology, such as ZL00249960.6 and ZL01272605.2, considering the arrangement of radial supports in the vacuum layer, the thickness of the vacuum layer between the outer shell and the inner tank has to be 100 mm or so. The inner support structure of the inner tank and the outer shell must not only be able to withstand the force generated by the liquid load, the weight of the storage tank and the corresponding impact acceleration, but also reduce the heat leakage caused by the inner support structure as much as possible, so the inner support structure is a cryogenic storage tank. key to design. Among the existing technologies, the upper and inner support structures of low-temperature storage tanks currently used at home and abroad include: 1) The heat-insulating pad structure between the inner tank and the outer shell, but it cannot effectively solve the problem of large heat leakage from the support due to the small distance between high-vacuum multi-layer heat insulation 2) The stainless steel casing structure between the inner and outer heads is difficult to manufacture, the distance between the inner and outer heads is large, and the impact resistance is poor. And the heat leakage is relatively large; 3) The structure of the suspension belt cannot effectively solve the problem of the decline in the impact resistance caused by thermal expansion and contraction; 4) The strong impact support structure of the low-temperature container of the utility model ZL00216678.X requires a large distance between the heads and When the normal temperature turns to low temperature, the contact gap increases and the impact resistance level decreases.

With the development of storage and transportation of low-temperature liquefied gas tanks in my country, how to effectively increase the storage volume of low-temperature liquefied gas and improve the level of heat insulation and impact resistance within a limited size range is the goal pursued by designers. The invention overcomes the shortcomings of the existing support design, and is characterized by thin heat insulation layer, superior heat insulation performance and large liquid storage volume.

Contents of the invention

Therefore, the object of the present invention is to provide a high-vacuum heat-insulated low-temperature liquefied gas storage tank, wherein a combination of radial force and axial force is adopted between the outer shell head and the inner liner head at the end of the tank body. The supporting structure, the combined supporting structure is processed by appropriate glass fiber reinforced plastic or similar materials, and the high-vacuum heat-insulated cryogenic liquefied gas storage tank provided by the present invention basically overcomes one or more problems caused by the limitations and shortcomings of the prior art.

Other advantages, purposes and characteristics of the present invention will be provided in the following description, for those skilled in the art, a part of advantages, purposes and characteristics can be clearly obtained through the following analysis or obtained through the present invention. obtained by practice. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description, claims hereof as well as the appended drawings.

In order to obtain these advantages and other advantages and according to the purpose of the present invention, as a specific and broad description to achieve the purpose of the invention, the high vacuum thermal insulation storage tank described in the present invention includes: a frame and a tank body, and the tank body is composed of It consists of an outer shell, an inner tank, a high-vacuum insulation layer between the outer shell and the inner tank, and a supporting structure connecting the outer shell and the inner tank. The outer shell and the inner tank include a straight section and a head, wherein the supporting structure is set A combined support structure that bears radial force and axial force between the outer shell head and the inner liner head at the end of the tank.

The storage tank of the present invention includes a frame and a tank body. For tank trucks, the frame refers to the vehicle chassis that is fixed to the tank body in some way; for tank containers, the frame refers to the container structure frame that is fixed in a certain way within a limited size range.

In the storage tank according to the present invention, since the combined supporting structure adopted therein is only arranged between the inner and outer heads at both ends of the tank body, compared with the tank bodies involved in utility models ZL00249960.6 and ZL01272605.2, the Radial support is added, thereby reducing the heat transfer area of the connecting surface between the inner tank and the outer shell, so as to obtain better heat insulation effect. The thickness of the layer can be reduced to 50 mm, which expands the effective volume of the inner tank and improves the loading efficiency.

According to the storage tank according to the present invention, the head of the liner is concave in the center to form a reversed small head, and the arc surface of the small head is opposite to the arc surface of the outer shell.

The tank body shell of the storage tank according to the present invention includes a left outer head body, an outer straight cylinder body, a right outer head body and a reinforcement ring. Different from the prior art, the shell reinforcement ring is arranged outside the shell, so that In the case of the same inner diameter of the shell and the same specifications of the reinforcing ring, the shell uses less material, has a small weight, low cost, and the reinforcing ring also plays a role in protecting the shell; the inner tank is composed of a left inner head body, an inner straight cylinder body, and a right inner head Body composition (according to Figure 2 shows the left and right sides of the tank body), the head of the inner tank and the head of the outer shell are installed in opposite directions, the inner tank is wound with multiple layers of heat insulating materials, and the inner tank and the outer shell are supported by the combination of the inner and outer heads at both ends Structure to connect, and bear radial force and axial force. Since the head of the inner tank and the head of the outer shell are installed in opposite directions, the combined support structure can be placed in the inner head, so that the gap between the inner and outer heads is narrower, so that when the outer shell is equal in size, the inner tank The effective loading volume is larger, which is not available in the tank bodies involved in the utility models ZL00216678.X, ZL00249960.6 and ZL01272605.2.

According to the storage tank of the present invention, wherein the support structure is provided with a support plate, which is in contact with the reversed small head; in addition, two fixing rings are provided for holding the support plate , the fixed rings are distributed on both sides of the support plate, and an automatically adjustable contact gap is set between the support plate and the reversed small head.

According to the storage tank according to the present invention, it also includes an axial support device arranged between the shell head and the liner head and passing through the central hole of the support plate, and the axial support device includes:

A support tube, fixed to the inner side of the shell head, and a protrusion is provided on the inner wall of the support tube;

A support shaft, fixed to the reversed small head, extends into the support tube through the protrusion;

a locking member disposed at the end of the support shaft; it may be a lock nut or similar, and a first spacer locked between the locking member and the protrusion and a second spacer, which is locked between the inverted small head and the protrusion of the support tube, and the distance between the inner tank head and the outer shell head of the support end used to transmit axial load in the support structure depends on the transmission The distance required for liquid sealing and thermal expansion and contraction compensation of pipes for discharging liquid and gas, for example, the distance may be about 300 mm. In addition, in order to improve the supporting strength of the supporting tube, the end of the supporting tube can also be an end with a reinforced structure.

According to the storage tank according to the present invention, it also includes a reinforcing tube fixed in the head of the shell, the reinforcing tube is arranged outside the supporting tube, and a reinforcing tube may be arranged between the reinforcing tube and the supporting tube. plate. In order to facilitate the installation of the inner tank, a horizontal process pipe matched with the support tube is arranged on a small inverted head of the inner tank, and a reinforcing plate is also arranged in the outer shell and the inner tank head.

The combined support structure mainly includes the left radial support plate, the right radial support plate, the right axial pad (the second pad referred to above), and the left axial pad (the first pad referred to above) and support tube. The left radial support plate is set at the left end of the tank body, and the right radial support plate is set at the right end of the tank body, jointly bearing the radial force generated by the inner tank and its loading medium; the right axial pad and the left axial pad are both It is installed at the left end of the tank body so that during the moving process of the tank body, the right and left axial loads generated by the inner tank and the loading medium, after pressing the right axial pad and the left axial pad, are transmitted through the support tube. Give the crust. Through the use of finite element structure and thermal analysis software, the inner support structure that can meet the requirements of force and heat leakage under the maximum loading rate is controlled and designed. As long as the clearance of the head with the axial support end meets the structural requirements when the pipe is drawn out, it can be truly realized. The internal support structure matching the high vacuum multilayer insulation structure has been established. The outer rings of the left radial support plate and the right radial support plate in the combined support structure are in contact with the stainless steel tube extending from the inner head body to the inner cylinder, which is beneficial to the arrangement of the axial support block and reduces the weight of the axial support block. Heat leakage, the inner ring of the FRP disk is in contact with the steel pipe on the outer head body, so that any radial force level is consistent, which improves the reliability of the structure, and the heat insulation performance is very good. The diameter of the inner tank and the outer shell The heat transfer surface is only the inner support force surface, and the rest of the cylindrical surface is radiation heat transfer, which completely avoids the heat leakage of the radial support of the tank involved in the utility models ZL00249960.6 and ZL01272605.2. The small spacing increases the loading rate. Select the appropriate material of the FRP support disc, and through finite element analysis and test verification, the contact gap between the inner and outer rings has self-adjustment ability. When the tank body changes from normal temperature to low temperature, the contact gap between the inner and outer rings of the radial support disc changes very little, greatly improving Improve the radial impact resistance, and facilitate the assembly and clearance control at room temperature. At the same time, this invention makes full use of the characteristics of the high ratio of compressive strength to thermal conductivity and the thermal contact resistance of the FRP material, so that the support has a large ability to withstand radial force and small heat leakage, which solves the problem of the utility model ZL00216678.X The large contact gap in the cold state is not conducive to the impact resistance problem in the strong impact support structure of the cryogenic vessel. Extend the length of the axial FRP briquetting block through the stainless steel tube extending from the inner head body to the inner cylinder, reduce the heat leakage of the axial support, and solve the axial support in the anti-strong impact support structure of the low-temperature vessel of the utility model ZL00216678.X The problem of uncontrollable heat leakage, while ensuring the maximum liquid storage volume in the effective space, satisfactorily solves the contradiction between internal support force and heat insulation.

Description of drawings

Fig. 1 is a schematic diagram of a high-vacuum multi-layer heat-insulated low-temperature liquefied gas storage tank of the present invention;

Fig. 2 is a schematic diagram of the tank body and the inner support structure.

In Figure 1, 37 is the frame, 38 is the tank body; in Figure 2, 1 is the left head of the shell, 2 is the reinforcement plate of the left head of the shell, 3 is the left head of the liner, 4 is the reinforcement plate of the left head of the liner, 5 is the left transition tube, 6 is the left reinforcing plate, 7 is the left reinforcing tube, 8 is the left reinforcing plate, 9 is the left fiberglass support tube, 10 is the left sealing plate, 11 is the supporting shaft, which can be a stainless steel shaft, 12 is a locking piece, which can be a nut, 13 is a left reversed small head, 14 is a left radial support plate, 15 is a second spacer, 16 is a first spacer, 17 is a left radial support plate left Fixed ring, 18 is the right fixed ring of the left radial support plate, 19 is the right radial support plate, 20 is the right reversed small head, 21 is the process tube, 22 is the right fixed ring of the right radial support plate, 23 is the right The left fixed ring of the radial support plate, 24 is the right head of the shell, 25 is the reinforcement plate of the right head of the shell, 26 is the right head of the inner tank, 27 is the reinforcement plate of the right head of the inner tank, 28 is the right transition tube, 29 is the right reinforcing plate, 30 is the right reinforcing tube, 31 is the right reinforcing plate, 32 is the right support pipe, 33 is the right sealing plate, 34 is the inner straight cylinder, 35 is the outer straight cylinder, 36 is the shell reinforcement ring, 39 is The high vacuum insulation layer, 40, is a multilayer winding insulation material.

Detailed ways:

The specific implementation of the present invention will be further described below in conjunction with the accompanying drawings. As shown in Figure 1, the present invention comprises a frame 37 and a tank body 38 welded together in an appropriate manner. As shown in Figure 2, the tank body includes the left shell head 1, the left shell head reinforcement plate 2, the inner tank left head head 3, the inner tank left head reinforcement plate 4, the left transition tube 5, and the left reinforcement plate 6 , left reinforcing tube 7, left reinforcing plate 8, left supporting tube 9, left sealing plate 10, stainless steel shaft 11, lock nut 12, left reversed small head 13, left radial supporting plate 14, second spacer 15. The first spacer 16, the left radial support plate left fixed ring 17, the left radial support plate right fixed ring 18, the right radial support plate 19, the right reversed small head 20, the process tube 21, the right radial Support plate right fixed ring 22, right radial support plate left fixed ring 23, shell right head 24, shell right head reinforcement plate 25, inner tank right head 26, inner tank right head reinforcement plate 27, right transition joint Tube 28, right reinforcing plate 29, right reinforcing tube 30, right reinforcing plate 31, right support pipe 32, right sealing plate 33, inner straight cylinder 34, outer straight cylinder 35, shell reinforcement ring 36, high vacuum insulation layer 39 and Multiple layers of wrapping insulation material 40 .

The left shell head 1, the left shell head reinforcement plate 2, the left reinforcement plate 6, the left reinforcement tube 7, the left reinforcement plate 8 and the left support pipe 9 are welded together to form the left outer head body.

The left inner tank head 3, the left transition tube 5, the left inner tank head reinforcing plate 4, the left reversed small head 13, the left radial support plate right fixing ring 18 and the stainless steel shaft 11 are welded together to form a left inner Head body.

The right shell head 24, the right shell reinforcement plate 25, the right reinforcement plate 29, the right reinforcement tube 30, the right reinforcement plate 31 and the right support pipe 32 are welded together to form the right outer head body.

The right head 26 of the inner tank, the right transition tube 28, the right reversed small head 20, the horizontal installation process pipe 21, the left fixed ring 23 of the right radial support plate and the right head reinforcement plate 27 of the inner tank are welded together to form Right inner head body.

The right outer head body 24 and the outer straight section 35 are welded to form an outer cylinder combined section. The left inner head body, the right inner head body and the inner straight section 34 are welded together to form an inner container. The outer surface of the liner is wrapped with multiple layers of heat insulating material 40 . In the installation process, firstly, put the right radial support plate 19 into the inner tank, then put the right radial support plate right fixed ring 22, and press the inner ring of the right radial support plate right fixed ring 22 with special tooling , the right fixed ring 22 of the right radial support plate is welded with the upper right transition tube 28 of the inner tank, and the combined section of the outer cylinder is inserted into the right radial support plate 19. Next, put the left radial support plate 14 into the inner tank, then put the left radial support plate left fixed ring 17, press the inner ring of the left radial support plate left fixed ring 17 with special tooling, and the left radial support The left fixed ring 17 is welded to the 5 corners of the upper left transition tube of the inner tank, the second spacer 15 is placed on the stainless steel support shaft 11 of the inner tank, and finally the left outer head body is inserted into the left radial support disc 14, The left head 1 on the left outer head body is welded to the combined section of the outer cylinder body. The first spacer 16 is put into the left support pipe 9, and is screwed onto the inner tank stainless steel supporting shaft 11 with the lock nut 12 to compress the first spacer 16 and the second spacer 15, the lock nut 12 and the stainless steel Support shaft 11 fillet welding realizes the installation of combined support. Finally, the corner welding of the left sealing plate 10 and the left reinforcing plate 6 and the corner welding of the right reinforcing plate 29 and the right sealing plate 33 form the tank body. A high vacuum is drawn between the shell and the inner bag to form a high vacuum insulation layer 39 . Shell reinforcing ring 36 is welded on the outer surface of the shell.

Of course, it can be understood that those skilled in the art can make any changes or deformations on the basis of the technical solution of the present invention, and they all should belong to the scope of the appended claims of the present invention.

Claims (12)

1. A high-vacuum heat-insulated low-temperature liquefied gas storage tank, comprising a frame and a tank body, the tank body is formed by an outer shell, an inner tank, a high-vacuum thermal insulation layer between the outer shell and the inner tank, and a supporting structure connecting the outer shell and the inner tank Composition, the outer shell and the inner tank include a straight section and a head, and it is characterized in that: the support structure is only arranged between the outer shell head and the inner tank head at the end of the tank to withstand radial force and The combined supporting structure of the axial force, and the center part of the head of the inner tank is inwardly recessed to form a reversed small head, and the arc surface of the small head is opposite to the arc surface of the outer shell. 2. The storage tank according to claim 1, characterized in that the distance between the outer shell and the inner tank of the storage tank is not greater than 50 mm. 3. The storage tank according to claim 1 or 2, wherein the supporting structure is provided with A support plate, which is in contact with the reversed small head; Two fixing rings are used to hold the supporting disc, and the fixing rings are distributed on both sides of the supporting disc, and there is an automatically adjustable contact gap between the supporting disc and the inverted small head . 4. The storage tank according to claim 3, characterized in that: a transition sleeve is provided between the inner tank head and the inverted small head, and the support structure is arranged in the transition sleeve . 5. The storage tank according to claim 3, further comprising an axial support device arranged between the shell head and the liner head and passing through the central hole of the support plate, said Axial support devices include: A support tube, fixed to the inner side of the shell head, and a protrusion is provided on the inner wall of the support tube; A support shaft, fixed to the reversed small head, extends into the support tube through the protrusion; a locking member disposed at the end of the support shaft; and a first spacer, locked between the locking member and the protrusion; The second spacer is locked between the reversed small head and the protrusion of the support tube. 6. The storage tank according to claim 5, characterized in that, the distance between the head of the liner and the head of the outer shell at the support end used to transmit axial load in the support structure depends on the pipe liquid used for transporting and discharging liquid and gas. The distance required for sealing and thermal expansion and contraction compensation. 7. The storage tank according to claim 5, further comprising a reinforcing tube fixed in the head of the shell, and the reinforcing tube is arranged on the outside of the support pipe. 8. The storage tank according to claim 7, wherein a reinforcement plate is further provided between the reinforcement tube and the support pipe. 9. The storage tank according to claim 5, wherein a horizontal process pipe matched with the support pipe is arranged on a reversed small head of the liner, so as to realize the guidance during horizontal installation or vertical installation position. 10 . The storage tank according to claim 1 , wherein a reinforcing plate is also arranged in the head of the outer shell and the inner tank. 11 . 11. The storage tank according to claim 1, characterized in that: the combined support structure adopts FRP with good mechanical performance and low thermal conductivity to bear and transmit various forces and cut off heat transfer, and utilizes contact thermal resistance Further reduce heat transfer. 12. The storage tank according to claim 1 or 2, characterized in that a reinforcement ring is provided on the outside of the shell.