Anti-layering device for LNG (Liquefied Natural Gas) storage tank

Abstract

The utility model relates to the technical field of LNG (Liquefied Natural Gas) storage tanks, in particular to an anti-layering device of an LNG storage tank, which comprises a tank body, a motor is arranged on the outer side wall of the upper part of the tank body, an output shaft of the motor horizontally extends into the tank body, the output shaft is fixed on an upper cross beam through an upper bearing seat, and two chain wheel discs A are symmetrically arranged on an output shaft body at an interval; the two chain wheel discs A are respectively matched and meshed with the upper end part of an annular chain, the lower end part of the annular chain is matched and meshed with chain wheel discs B, the chain wheel discs B are symmetrically arranged on a rotating shaft body at intervals, a rotating shaft is fixed on a lower cross beam through a lower bearing seat, and a plurality of hoppers are uniformly arranged on the outer side of the annular chain at intervals and are used for mixing and stirring LNG in the vertical direction; according to the anti-layering device for the LNG storage tank, LNG in the storage tank can be uniformly mixed in the vertical direction, and layering in the vertical direction is effectively prevented.

Description

Technical Field

[0001] This utility model relates to the field of LNG storage tank technology, and in particular to an LNG storage tank anti-stratification device. Background Technology

[0002] Natural gas is a mixture of gases, and the different gases have different densities. When storing natural gas, the temperature is generally lowered below the boiling point, and liquefied natural gas (LNG) is stored at atmospheric pressure.

[0003] LNG is susceptible to diurnal or seasonal temperature changes, low-flow-rate injection of new LNG, and other factors that can lead to stratification. Essentially, this is the vertical separation of liquid layers of different densities within the storage tank. Tank shapes, such as vertical tanks with a large height-to-diameter ratio, restrict the natural convection of gas and liquid, exacerbating stratification. Stratification can trigger a "rollover" phenomenon, causing a sudden increase in tank pressure and posing safety hazards. The pressure inside the tank is usually regulated by venting the upper layer of gas, which causes environmental pollution and wastes LNG resources. Some LNG storage tanks are equipped with stirring devices to prevent stratification by agitating the LNG inside the tank, but horizontal stirring is not ideal and it is difficult to achieve uniform vertical mixing of the LNG inside the tank.

[0004] Therefore, this application provides an anti-stratification device for LNG storage tanks to solve the problems mentioned in the background art. Summary of the Invention

[0005] The purpose of this invention is to provide an anti-stratification device for LNG storage tanks, which solves the problem of LNG stratification easily occurring in the vertical direction inside existing LNG storage tanks.

[0006] To solve the above-mentioned technical problems, this utility model provides an anti-stratification device for LNG storage tanks, including a tank body. A motor is installed on the upper outer wall of the tank body. The output shaft of the motor extends horizontally into the tank body. The output shaft is fixed to the upper crossbeam through an upper bearing seat. Two sprocket discs A are symmetrically arranged on the output shaft body. The two sprocket discs A are respectively adapted to mesh with the upper end of an annular chain. The lower end of the annular chain is adapted to mesh with two sprocket discs B. The two sprocket discs B are symmetrically arranged on the rotating shaft body. The rotating shaft is fixed to the lower crossbeam through a lower bearing seat. Several hoppers are evenly arranged on the outer side of the annular chain. The hoppers are used for vertical mixing and stirring of LNG.

[0007] A further improvement of this utility model is that: sprocket disk A and sprocket disk B have the same structure and size, and several holes are opened on the body of sprocket disk A and sprocket disk B. The holes are used for horizontal convection of LNG and reduce their own weight.

[0008] A further improvement of the present invention is that the sprocket disk A also includes grooves A and triangular teeth arranged sequentially at intervals on the outer arc surface of the main body, and grooves B are provided on both sides of the triangular teeth.

[0009] A further improvement of the present invention is that the annular chain includes several first and second chain links that are connected end to end. The first and second chain links are arranged perpendicularly to each other. The first chain link is adapted to groove A and groove B, and the second chain link is adapted to meshing triangular teeth.

[0010] A further improvement of this utility model is that: several hoppers are vertically and evenly spaced on the outer side of the first chain link corresponding to the horizontal direction. The hoppers are trapezoidal structures with larger tops and smaller bottoms, and the length of the hoppers is equal to the vertical distance between the two sprocket discs A.

[0011] A further improvement of this utility model is that: an upper crossbeam and a lower crossbeam are symmetrically arranged horizontally inside the tank, and the two ends of the upper crossbeam and the lower crossbeam are respectively fixed to the inner wall of the tank. An upper bearing seat and a lower bearing seat are symmetrically arranged in the middle of the top surface of the upper crossbeam and the lower crossbeam respectively.

[0012] A further improvement of this utility model is that the vertical distance between the top of the sprocket disc A and the top wall of the tank, and the vertical distance between the bottom of the sprocket disc B and the bottom wall of the tank, are both greater than the width of the hopper.

[0013] A further improvement of this utility model is that the horizontal distance between the outer wall of sprocket A and the inner wall of the upper bearing seat is equal to the horizontal distance between the outer wall of sprocket B and the inner wall of the lower bearing seat, both being 5~10cm.

[0014] A further improvement of this utility model is that the horizontal distance between the outer edges of the hoppers on both sides of the annular chain is 1 / 2 to 2 / 3 of the inner diameter of the tank.

[0015] By adopting the above technical solution, this utility model has the following beneficial effects:

[0016] 1. This utility model provides an anti-stratification device for LNG storage tanks. The anti-stratification device uses sprocket A and sprocket B to mesh with a ring chain. A hopper is set on the outside of the ring chain body. The ring chain is driven to rotate by sprocket A, which drives the LNG in the trapezoidal hopper to move continuously up and down, forming a three-dimensional circulating flow. When rising, the hopper carries the high-density liquid at the bottom and transports it upward. When the top flips, it realizes gas-liquid interface disturbance and gravity pouring mixing. When descending, it drives the surface liquid to form a downward vortex. Compared with traditional stirring devices, the LNG is mixed more evenly in the vertical direction, the mixing time is shortened by 35%, and the stratification suppression duration is extended by 3-5 times.

[0017] 2. The present invention provides an LNG storage tank anti-stratification device. The movement of the chain and hopper will generate complex convection in the liquid, making the LNG flow more frequently in the vertical and horizontal directions. This convection helps to bring the high-density components at the bottom of the LNG storage tank to the top, while bringing the low-density components at the top to the bottom, further promoting the mixing of LNG and preventing stratification caused by density differences.

[0018] 3. The present invention provides an anti-segregation device for LNG storage tanks. The sprocket discs A and B are connected by grooves A and triangular teeth arranged at intervals. At the same time, grooves B are provided on both sides of the triangular teeth, which can well mesh with the ring chain and effectively prevent the ring chain from disengaging from sprocket discs A or B.

[0019] 4. The present invention provides an anti-stratification device for LNG storage tanks. The hopper has a trapezoidal structure. After the material is taken from the bottom of the LNG storage tank, the trapezoidal design of the hopper can provide better structural stability. Especially when the hopper is full of liquid, the wider top can distribute the weight, reduce the pressure on the bottom, and at the same time help the liquid to flow out of the hopper smoothly. Attached Figure Description

[0020] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0021] Figure 1 A schematic diagram of an anti-stratification device for an LNG storage tank;

[0022] Figure 2 for Figure 1 Front sectional view in the middle;

[0023] Figure 3 This is a structural diagram of the upper and lower crossbeams;

[0024] Figure 4 This is a magnified view of a portion of the sprocket A and the ring chain;

[0025] Figure 5 This is a schematic diagram of the structure of sprocket disk A;

[0026] Figure 6 This is a magnified view of a portion of sprocket A.

[0027] Reference numerals in the attached diagram: 1. Tank body; 2. Motor; 21. Output shaft; 3. Upper crossbeam; 31. Upper bearing seat; 4. Lower crossbeam; 41. Lower bearing seat; 5. Sprocket disc A; 51. Hole; 52. Groove A; 53. Triangular tooth; 531. Groove B; 6. Annular chain; 61. First link; 62. Second link; 7. Sprocket disc B; 71. Rotating shaft; 8. Hopper. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0029] In the description of this utility model, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0030] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0031] The present invention will be further explained below with reference to specific embodiments.

[0032] like Figures 1-6As shown, this embodiment provides an anti-stratification device for an LNG storage tank, including a tank body 1. A motor 2 is installed on the upper outer wall of the tank body 1. The output shaft 21 of the motor 2 extends horizontally into the tank body 1. A crossbeam 3 is also installed inside the tank body 1, and a bearing seat 31 is installed on the crossbeam 3. The output shaft 21 of the motor 2 is adapted and fixed to the inner ring of the bearing in the bearing seat 31. Two sprocket discs A5 are symmetrically arranged on the body of the output shaft 21. The two sprocket discs A5 are adapted to mesh with the upper end of an annular chain 6, and the lower end of the annular chain 6 is adapted to mesh with two sprocket discs B7. The two sprocket discs B7 are symmetrically arranged on the body of a rotating shaft 71. The rotating shaft 71 is fixed to the lower crossbeam 4 through a lower bearing seat 41. Several hoppers 8 are evenly arranged on the outer side of the annular chain 6. The hoppers 8 are used for vertical mixing and stirring of LNG. Specifically, the flange of the motor 2 is fixed to the outer wall of the tank body 1, and the flange fixing point meets the relevant sealing requirements. The output shaft 21 of the motor 2 extends horizontally into the tank 1. The output shaft 21 passes through the upper bearing seat 31, two symmetrical sprocket discs A5, and the upper bearing seat 31 in sequence. The output shaft 21 and the upper bearing seat 31 are connected by a bearing, and the output shaft 21 rotates within the bearing. The output shaft 21 and the sprocket discs A5 are connected by a key, and the two are fixedly connected relative to each other. The two sprocket discs A5 respectively mesh with the upper ends of two annular chains 6, and the lower ends of the two annular chains 6 mesh with two symmetrical sprocket discs B7. The hoppers 8 are horizontally arranged on the bodies of the two annular chains 6. When the motor 2 drives the output shaft 21 to rotate, it drives the two sprocket discs A5 to rotate. The two sprocket discs A5 synchronously drive the annular chains 6 to make annular motion, which drives the trapezoidal hoppers 8 to continuously rise and fall in the LNG, continuously lifting the bottom liquid and continuously driving the surface liquid to form a downward vortex, so as to realize the continuous mixing of LNG in the vertical direction and effectively prevent the stratification of the upper and lower layers.

[0033] like Figure 3-6As shown, in this embodiment, sprocket discs A5 and B7 have the same structure and size. Several holes 51 are formed on the bodies of sprocket discs A5 and B7. These holes 51 are used for horizontal convection of LNG and to reduce their own weight. Sprocket disc A5 also includes grooves A52 and triangular teeth 53 arranged at intervals on the outer arc surface of its body. Grooves B531 are provided on both sides of the triangular teeth 53. The annular chain 6 includes several first links 61 and second links 62 connected end-to-end. The first links 61 and second links 62 are arranged perpendicularly to each other. The first links 61 are adapted to grooves A52 and B531, and the second links 62 are adapted to meshing triangular teeth 53. Specifically, sprocket disc A5 is a disc with a certain thickness. Sprocket disc A5 and sprocket disc B7... The B7 body has several holes 51 of different shapes, which not only reduces its own weight and facilitates the installation of triangular teeth 53, but also enhances the horizontal convection of LNG and improves the uniformity of LNG. The outer arc surface of the sprocket disc A5 body has an integral groove A52, and the triangular teeth 53 are screwed to the outer arc surface of the sprocket disc A5 body. The two sides of the triangular teeth 53 have integral grooves B531. The bottom surface of the groove A52 is arc-shaped, which can fit well with the cylindrical ring chain 6. At the same time, the triangular teeth 53 can fit into the gap of the second chain link 62 parallel to the outer arc surface of the sprocket disc A5. The adjacent second chain link 62 fits the grooves A52 and B531. The groove B531 makes the second chain link 62 rotate more smoothly and fit better on the sprocket disc A5.

[0034] like Figure 4 , Figure 6 As shown, in this embodiment, several hoppers 8 are vertically and evenly spaced on the outer side of the horizontally corresponding first chain link 61. The hoppers 8 have a trapezoidal structure that is larger at the top and smaller at the bottom, and the length of the hoppers 8 is equal to the vertical distance between the two sprocket discs A5. Specifically, several hoppers 8 are screwed and fixed at equal intervals on the outer side of the horizontally corresponding first chain link 61 between the two annular chains 6, so that the two annular chains 6 can synchronously drive the hoppers 8 to move up, overturn, tilt, and down in the LNG storage tank. The two sprocket discs A5 are fixed to the upper crossbeam 3 through the upper bearing seat 31. The length of the hoppers 8 is equal to the vertical distance between the two sprocket discs A5, so that the hoppers 8 can move up and down between the two upper crossbeams 3 or the lower crossbeam 4 while meeting the installation requirements.

[0035] like Figures 2-3 As shown, in this embodiment, an upper crossbeam 3 and a lower crossbeam 4 are symmetrically arranged horizontally inside the tank 1. The two ends of the upper crossbeam 3 and the lower crossbeam 4 are respectively fixed to the inner wall of the tank 1. An upper bearing seat 31 and a lower bearing seat 41 are symmetrically arranged in the middle of the top surface of the upper crossbeam 3 and the lower crossbeam 4, respectively. Specifically, the upper crossbeam 3 and the lower crossbeam 4 are two horizontally symmetrical cuboid rods, which are used to fix the upper bearing seat 31 and the lower bearing seat 41, respectively. The upper bearing seat 31 and the lower bearing seat 41 are used to install and fix the sprocket disc A5 and the sprocket disc B7.

[0036] like Figures 2-3 As shown, in this embodiment, the vertical distance between the top of sprocket A5 and the top wall of tank 1, and the vertical distance between the bottom of sprocket B7 and the bottom wall of tank 1 are both greater than the width of hopper 8; the horizontal distance between the outer wall of sprocket A5 and the inner wall of upper bearing seat 31 is equal to the horizontal distance between the outer wall of sprocket B7 and the inner wall of lower bearing seat 41, both being 5cm; the horizontal distance between the outer edges of hopper 8 on both sides of the annular chain 6 is 1 / 2 to 2 / 3 of the inner diameter of tank 1; specifically, when hopper 8 makes an annular motion in the LNG storage tank, it does not contact the top and bottom walls of tank 1, and the outer walls of the two sprockets A5 and the two sprockets B7 are 5cm away from the inner walls of upper bearing seat 31 and lower bearing seat 41, respectively, so that the two sprockets A5 and the two sprockets B7 can rotate without friction between upper bearing seat 31 and lower bearing seat 41, respectively.

[0037] This utility model provides a working principle for an LNG storage tank anti-stratification device: During use, the operator starts the motor 2 and adjusts the output shaft 21 of the motor 2 to a suitable speed. The output shaft 21 then drives two sprocket discs A5 to rotate synchronously. The two sprocket discs A5 synchronously drive the ring chain 6 to move in a ring, which in turn drives the trapezoidal hopper 8 to move up and down continuously in the LNG. When the hopper 8 rises, it carries the high-density liquid at the bottom layer upwards. When the top of the hopper 8 flips, it realizes gas-liquid interface disturbance and gravity-induced mixing. When the hopper 8 descends, it drives the surface liquid to form a downward vortex. The mixing time is shortened by 35%, and the stratification suppression duration is extended by 3-5 times.

[0038] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. An anti-stratification device for LNG storage tanks, characterized in that, The device includes a tank (1), a motor (2) is installed on the upper outer wall of the tank (1), the output shaft (21) of the motor (2) extends horizontally into the tank (1), a crossbeam (3) is also installed inside the tank (1), a bearing seat (31) is also installed on the crossbeam (3), the output shaft (21) of the motor (2) is adapted and fixed to the inner ring of the bearing seat (31), two sprocket discs A (5) are symmetrically arranged on the body of the output shaft (21), the two sprocket discs A (5) are adapted to mesh with the upper end of the ring chain (6), the lower end of the ring chain (6) is adapted to mesh with two sprocket discs B (7), the two sprocket discs B (7) are symmetrically arranged on the body of the rotating shaft (71), the rotating shaft (71) is fixed to the lower crossbeam (4) through the lower bearing seat (41), and several hoppers (8) are evenly arranged on the outer side of the ring chain (6), the hoppers (8) are used for vertical mixing and stirring of LNG.

2. The LNG storage tank anti-stratification device according to claim 1, characterized in that... Sprocket A (5) and sprocket B (7) have the same structure and size. Several holes (51) are opened on the body of sprocket A (5) and sprocket B (7). The holes (51) are used for horizontal convection of LNG and to reduce their own weight.

3. The LNG storage tank anti-stratification device according to claim 2, characterized in that, The sprocket A (5) also includes grooves A (52) and triangular teeth (53) arranged sequentially on the outer arc surface of the main body, and grooves B (531) are arranged on both sides of the triangular teeth (53).

4. The LNG storage tank anti-stratification device according to claim 1, characterized in that, The ring chain (6) includes several first links (61) and second links (62) that are connected end to end. The first links (61) and second links (62) are arranged perpendicular to each other. The first link (61) is adapted to groove A (52) and groove B (531), and the second link (62) is adapted to meshing triangular teeth (53).

5. The LNG storage tank anti-stratification device according to claim 4, characterized in that, Several hoppers (8) are vertically and evenly spaced on the outer side of the first chain link (61) corresponding to the horizontal direction. The hoppers (8) are trapezoidal structures with larger tops and smaller bottoms. The length of the hoppers (8) is equal to the vertical distance between the two sprocket discs A (5).

6. The LNG storage tank anti-stratification device according to claim 1, characterized in that... The tank body (1) is symmetrically equipped with an upper crossbeam (3) and a lower crossbeam (4) at the top and bottom. The two ends of the upper crossbeam (3) and the lower crossbeam (4) are fixed to the inner wall of the tank body (1). The upper bearing seat (31) and the lower bearing seat (41) are symmetrically equipped in the middle of the top surface of the upper crossbeam (3) and the lower crossbeam (4).

7. The LNG storage tank anti-stratification device according to claim 2, characterized in that, The vertical distance between the top of sprocket A (5) and the top wall of tank (1), and the vertical distance between the bottom of sprocket B (7) and the bottom wall of tank (1) are both greater than the width of hopper (8).

8. The LNG storage tank anti-stratification device according to claim 7, characterized in that, The horizontal distance between the outer wall of sprocket A (5) and the inner wall of the upper bearing seat (31) is equal to the horizontal distance between the outer wall of sprocket B (7) and the inner wall of the lower bearing seat (41), both being 5~10cm.

9. The LNG storage tank anti-stratification device according to claim 5, characterized in that, The horizontal distance between the outer edges of the hoppers (8) on both sides of the ring chain (6) is 1 / 2 to 2 / 3 of the inner diameter of the tank body (1).

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