Graded natural gas liquefaction and purification device

Abstract

The invention discloses a graded natural gas liquefaction and purification device, and relates to the technical field of natural gas liquefaction. Comprising a gas supply pipeline connected with a natural gas supply system; gas outlets are formed in the tops of the liquefying chambers, gas inlets are formed in the side faces of the bottoms of the liquefying chambers, the liquefying chambers are arranged in multiple groups, and every two adjacent liquefying chambers in each group are connected in series through a communicating pipeline to form a multi-stage liquefying treatment structure; one end of the input pipe is connected into the gas supply pipeline, and the other end of the input pipe is connected with the gas inlet of the liquefaction chamber; and the annular covers are mounted in the liquefaction chamber at equal intervals. By arranging the multiple liquefaction chambers, multi-stage liquefaction treatment can be achieved, and the liquefaction effect is improved; by arranging the cooling cover and the annular cover which are distributed in a staggered mode and arranging the first circulating cooling pipe and the second circulating cooling pipe in the cooling cover and the annular cover correspondingly, natural gas can be cooled and liquefied more efficiently and fully, and the reliability is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of natural gas liquefaction, and in particular to a graded natural gas liquefaction and purification device. Background Art

[0002] As global energy demand continues to grow, natural gas, as a clean and efficient energy source, has gradually increased its share in the energy structure. The main component of natural gas is methane, which has the advantages of high combustion efficiency and low emission pollution. However, natural gas is in gaseous state at normal temperature and pressure, which is not convenient for storage and transportation. Therefore, liquefying natural gas into liquefied natural gas is an effective way to solve this problem.

[0003] Existing natural gas liquefaction technologies mainly include cryogenic liquefaction, expansion refrigeration and adsorption. Among them, cryogenic liquefaction is the most commonly used method, which cools natural gas to below -162°C through multi-stage compression, cooling and throttling expansion processes to liquefy it.

[0004] After searching, the application scheme of Chinese patent application number CN201721014217.3 discloses a natural gas liquefaction equipment, which includes a liquefaction system and a refrigeration cycle system, wherein the mixed refrigerant primary compressor, primary cooler, gas phase outlet of the mixed refrigerant primary separator, mixed refrigerant secondary compressor, secondary cooler and mixed refrigerant secondary separator in the refrigeration cycle system are connected in sequence, and the liquid phase outlet of the mixed refrigerant secondary separator is connected in sequence with the refrigerant heat exchanger and primary throttle valve in the liquefaction system. The natural gas liquefaction equipment in the above-mentioned document has the following shortcomings: in the cooling link, ordinary heat exchangers and other structures are used, and the liquefaction effect is not good, which needs to be improved. Summary of the invention

[0005] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a staged natural gas liquefaction and purification device.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions:

[0007] A staged natural gas liquefaction and purification device, comprising:

[0008] Gas supply pipeline, the gas supply pipeline is connected to the natural gas supply system;

[0009] The liquefaction chamber has a gas outlet at the top and a gas inlet at the bottom side of the liquefaction chamber. The liquefaction chamber is arranged in multiple groups, and two adjacent liquefaction chambers in each group are connected in series through a connecting pipeline to form a multi-stage liquefaction treatment structure;

[0010] An input pipe, one end of which is connected to the gas supply pipeline, and the other end of which is connected to the gas inlet of the liquefaction chamber;

[0011] The annular cover is installed in the liquefaction chamber at equal distances. The cooling cover is an inverted bucket-shaped structure with a middle part bulging upwards. The first circulating cooling pipe is installed in the annular cover;

[0012] The cooling hood is equidistantly arranged in the liquefaction chamber, and the cooling hood and the annular hood are staggered. The central axes of the liquefaction chamber, the cooling hood and the annular hood coincide with each other, and the middle part of the cooling hood bulges upward. A second circulating cooling pipe is installed in the cooling hood, and the first circulating cooling pipe and the second circulating cooling pipe are both connected to the coolant circulating refrigeration system; the diameter of the bottom of the cooling hood is larger than the inner diameter of the top of the annular hood.

[0013] As a preferred embodiment of the present invention: the bottom of the annular cover is connected to an annular flow focusing frame through a connecting rod, an annular collecting groove is formed between the annular flow focusing frame and the inner wall of the liquefaction chamber, and the height of the annular collecting groove gradually decreases towards a position away from the center of the liquefaction chamber; the annular cover is provided with circumferentially distributed leaks, and the leaks are located above the annular collecting groove.

[0014] As a preferred embodiment of the present invention: a first drain pipe is arranged at the bottom of the liquefaction chamber, a second drain pipe is installed on the side of the liquefaction chamber, and one end of the second drain pipe passes through the liquefaction chamber and is connected to the annular collecting tank.

[0015] As a preferred embodiment of the present invention: both ends of the first circulating cooling pipe are connected to auxiliary pipes, one end of the auxiliary pipe is connected to the circulating pipe, the top of the circulating pipe is connected to a connecting seat, a connecting pipe is installed on the connecting seat, the connecting pipe is connected to the circulating liquid supply pipe, the circulating liquid supply pipe is connected to the coolant circulation refrigeration system, the circulating pipe is connected to the connecting pipe after passing through the internal passage of the connecting seat; a support rod is installed on the top of the cooling cover, the support rod passes through the liquefaction chamber and is connected to the connecting seat, and both ends of the second circulating cooling pipe are connected to the connecting seat after passing through the support rod liquid delivery passage.

[0016] As a preferred embodiment of the present invention: an annular plate is arranged on the outside of the cooling hood, a heat transfer rotating frame is rotatably installed on the outside of the annular plate, a heat transfer rotating seat is installed on the heat transfer rotating frame, and circumferentially distributed heat transfer blades are arranged on the outside of the heat transfer rotating seat; a guide pipe is arranged at the bottom of the cooling hood, the top end of the guide pipe is connected to the top of the cooling hood, and the bottom end of the guide pipe extends to above the annular hood.

[0017] As a preferred embodiment of the present invention, matching annular grooves are provided on the inner side of the heat transfer rotating frame and the outer side of the annular plate, and a plurality of balls are movably installed in the annular grooves.

[0018] As a preferred embodiment of the present invention: an annular heat transfer frame is fixed on the top of the annular cover, and a plurality of circumferentially distributed heat transfer bellows are fixed on the top of the annular heat transfer frame, and one end of the heat transfer bellows is fixed to the bottom of the heat transfer blade; two heat transfer rotating frames are respectively arranged on the upper and lower sides of the heat transfer rotating seat, and the two heat transfer rotating frames are connected by a guide rod, and the heat transfer rotating seat slides up and down on the outer wall of the guide rod.

[0019] As a preferred embodiment of the present invention: an annular frame is installed on the outer side of one end of the support rod close to the cooling cover, and the annular frame and a heat transfer rotating frame are connected through a clockwork spring.

[0020] As a preferred embodiment of the present invention: the input pipe is provided with a control valve for controlling the on-off and opening degree of the input pipe.

[0021] As a preferred embodiment of the present invention: the connecting pipeline includes:

[0022] a first delivery pipe, the first delivery pipe being detachably connected to a gas outlet of a liquefaction chamber;

[0023] a second delivery pipe, the second delivery pipe being detachably connected to the air inlet of another liquefaction chamber;

[0024] A third delivery pipe, one end of the third delivery pipe is detachably connected to the first delivery pipe, the other end of the third delivery pipe is detachably connected to the second delivery pipe, and an air pump is arranged on the third delivery pipe.

[0025] The beneficial effects of the present invention are:

[0026] 1. The present invention can realize multi-stage liquefaction processing by arranging multiple liquefaction chambers, thereby improving the liquefaction effect; by arranging staggered cooling hoods and annular hoods, and arranging the first circulating cooling pipe and the second circulating cooling pipe in the cooling hood and the annular hood respectively, the natural gas can be cooled and liquefied more efficiently and fully, thereby improving reliability.

[0027] 2. The present invention provides an annular flow concentrator and other structures. When natural gas is liquefied on the annular slope at the bottom of the annular cover, it can flow along the slope and fall into the annular collection tank. When natural gas is liquefied on the annular slope at the bottom of the cooling cover, it first drips from the cooling cover to the annular slope at the top of the annular cover, and then is discharged into the annular collection tank through the leak.

[0028] 3. The present invention, by providing structures such as heat transfer blades, can drive the heat transfer rotating seat to rotate based on the action of airflow on the heat transfer blades, thereby promoting the liquefaction of natural gas.

[0029] 4. The present invention can more fully contact with natural gas and promote natural gas liquefaction by setting a heat transfer bellows. The heat transfer bellows restricts the rotation of the heat transfer rotating seat, but can automatically adjust the contact effect with natural gas according to the speed of the airflow; this method can well avoid insufficient cooling due to excessive airflow speed, thereby improving reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 This is a schematic structural diagram of a hierarchical natural gas liquefaction and purification device proposed by the present invention;

[0031] Figure 2 This is a schematic structural diagram of a series connection of liquefied tanks of a staged natural gas liquefaction and purification device proposed by the present invention;

[0032] Figure 3 This is a schematic structural diagram of a cross-section of a liquefaction tank of a staged natural gas liquefaction and purification device proposed by the present invention;

[0033] Figure 4 This is a schematic diagram of the structure of an annular frame and a spring spring of a graded natural gas liquefaction and purification device proposed by the present invention;

[0034] Figure 5 This is a schematic diagram of the structure of a cooling hood and annular hood of a staged natural gas liquefaction and purification device proposed by the present invention;

[0035] Figure 6 This is a schematic structural diagram of a cross-section of a cooling hood and an annular hood of a staged natural gas liquefaction and purification device proposed by the present invention.

[0036] In the figure: 1 liquefaction chamber, 2 first delivery pipe, 3 connecting seat, 4 connecting pipe, 5 circulating liquid supply pipe, 6 circulating pipe, 7 air supply pipe, 8 control valve, 9 first liquid discharge pipe, 10 third delivery pipe, 11 air pump, 12 second liquid discharge pipe, 13 second delivery pipe, 14 support rod, 15 annular cover, 16 heat transfer blade, 17 heat transfer bellows, 18 annular frame, 19 spring, 20 auxiliary pipe, 21 cooling cover, 22 heat transfer rotating seat, 23 annular flow focusing frame, 24 heat transfer rotating frame, 25 guide rod, 26 leak, 27 first circulating cooling pipe, 28 annular heat transfer frame, 29 ball, 30 guide pipe. DETAILED DESCRIPTION

[0037] The technical solution of the present invention is further described in detail below in conjunction with specific implementation methods.

[0038] Embodiments of the present invention are described in detail below, examples of which are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.

[0039] Embodiment 1:

[0040] A staged natural gas liquefaction and purification device, such as Figure 1-6 As shown, including:

[0041] A gas supply pipeline 7, the gas supply pipeline 7 is connected to a natural gas supply system;

[0042] The liquefaction chamber 1 has a gas outlet at the top and a gas inlet at the bottom side of the liquefaction chamber 1. The liquefaction chamber 1 is arranged in multiple groups. Two adjacent liquefaction chambers 1 in each group are connected in series through a connecting pipeline to form a multi-stage liquefaction processing structure, that is, one end of the connecting pipeline is connected to the gas outlet of one liquefaction chamber 1, and the other end is connected to the gas inlet of another liquefaction chamber 1.

[0043] An input pipe, one end of which is connected to the gas supply pipeline 7, and the other end of which is connected to the gas inlet of the liquefaction chamber 1;

[0044] The annular cover 15 is installed at equal distances in the liquefaction chamber 1. The cooling cover 21 is an inverted bucket-shaped structure with a middle portion bulging upward. A first circulating cooling pipe 27 is installed in the annular cover 15.

[0045] The cooling cover 21 is equidistantly arranged in the liquefaction chamber 1, and the cooling cover 21 and the annular cover 15 are staggered, the central axes of the liquefaction chamber 1, the cooling cover 21 and the annular cover 15 coincide, the middle part of the cooling cover 21 bulges upward, a second circulating cooling pipe is installed in the cooling cover 21, and the first circulating cooling pipe 27 and the second circulating cooling pipe are both connected to the coolant circulating refrigeration system; the diameter of the bottom of the cooling cover 21 is greater than the inner diameter of the top of the annular cover 15;

[0046] By setting up multiple liquefaction chambers 1, multi-stage liquefaction processing can be achieved, thereby improving the liquefaction effect; by setting up staggered cooling covers 21 and annular covers 15, and arranging the first circulating cooling pipe 27 and the second circulating cooling pipe in the cooling cover 21 and the annular cover 15 respectively, the natural gas can be cooled and liquefied more efficiently and fully, thereby improving reliability.

[0047] In order to facilitate the collection of liquefied natural gas; Figure 5 As shown, the bottom of the annular cover 15 is connected to an annular flow focusing frame 23 through a connecting rod, and an annular collection groove is formed between the annular flow focusing frame 23 and the inner wall of the liquefaction chamber 1, and the height of the annular collection groove gradually decreases toward a position away from the center of the liquefaction chamber 1; the annular cover 15 is provided with circumferentially distributed leakage openings 26, and the leakage openings 26 are located above the annular collection groove;

[0048] By providing structures such as the annular flow concentrator 23, when natural gas is liquefied on the annular slope at the bottom of the annular cover 15, it can flow along the slope and fall into the annular collecting tank. When natural gas is liquefied on the annular slope at the bottom of the cooling cover 21, it first drips from the cooling cover 21 to the annular slope at the top of the annular cover 15, and then is discharged into the annular collecting tank through the leak 26.

[0049] In order to facilitate the export of liquefied natural gas; Figure 1 As shown, a first liquid drain pipe 9 is provided at the bottom of the liquefaction chamber 1, and a second liquid drain pipe 12 is installed on the side of the liquefaction chamber 1. One end of the second liquid drain pipe 12 passes through the liquefaction chamber 1 and is connected to the annular collection tank;

[0050] By providing the second liquid discharge pipe 12 and the first liquid discharge pipe 9 , the liquefied natural gas can be easily discharged. In addition, valve bodies can be provided on the second liquid discharge pipe 12 and the first liquid discharge pipe 9 for easy control.

[0051] In order to facilitate the delivery of coolant; Figure 1-3 As shown, both ends of the first circulating cooling pipe 27 are connected to the auxiliary pipe 20, one end of the auxiliary pipe 20 is connected to the circulating pipe 6, the top of the circulating pipe 6 is connected to the connecting seat 3, the connecting pipe 4 is installed on the connecting seat 3, the connecting pipe 4 is connected to the circulating liquid supply pipe 5, the circulating liquid supply pipe 5 is connected to the coolant circulating refrigeration system, and the circulating pipe 6 is connected to the connecting pipe 4 after passing through the internal passage of the connecting seat 3; the top of the cooling cover 21 is installed with a support rod 14, the support rod 14 passes through the liquefaction chamber 1 and is connected to the connecting seat 3, and the two ends of the second circulating cooling pipe are connected to the connecting seat 3 after passing through the liquid delivery passage of the support rod 14;

[0052] Among them, the specific internal passage structure of the support rod 14 and the connecting seat 3 can adopt the existing technology, and it is only necessary to realize the circulation function. For example, one end of an internal passage is connected to the end of a connecting tube 4, and the other end is connected to a circulation tube 6 and a liquid delivery passage in the support rod 14. One end of another internal passage is connected to the end of another connecting tube 4, and the other end is connected to another circulation tube 6 and another liquid delivery passage in the support rod 14, so as to realize circulation, or other methods can be adopted, which will not be repeated here.

[0053] In order to improve the cooling liquefaction effect; Figure 4-6 As shown, an annular plate is arranged outside the cooling cover 21, a heat transfer rotating frame 24 is rotatably installed outside the annular plate, a heat transfer rotating seat 22 is installed on the heat transfer rotating frame 24, and heat transfer blades 16 distributed circumferentially are arranged outside the heat transfer rotating seat 22; the heat transfer rotating frame 24, the heat transfer rotating seat 22 and the heat transfer blades 16 are all made of materials that are easy to transfer heat; a guide pipe 30 is arranged at the bottom of the cooling cover 21, the top end of the guide pipe 30 is connected to the top of the cooling cover 21, and the bottom end of the guide pipe 30 extends to the top of the annular cover 15;

[0054] By providing structures such as the heat transfer blades 16 , the heat transfer rotating seat 22 can be driven to rotate based on the airflow acting on the heat transfer blades 16 , thereby promoting the liquefaction of natural gas.

[0055] In order to improve the smoothness of rotation; Figure 6 As shown, the inner side of the heat transfer rotating frame 24 and the outer side of the annular plate are provided with matching annular grooves, and a plurality of balls 29 are movably installed in the annular grooves;

[0056] By providing the ball bearing 29, the smoothness of the rotation is improved.

[0057] In order to improve the cooling liquefaction effect; Figure 5 , Figure 6 As shown, an annular heat transfer frame 28 is fixed on the top of the annular cover 15, and a plurality of circumferentially distributed heat transfer bellows 17 are fixed on the top of the annular heat transfer frame 28, and one end of the heat transfer bellows 17 is fixed to the bottom of the heat transfer blade 16; two heat transfer rotating frames 24 are respectively arranged on the upper and lower sides of the heat transfer rotating seat 22, and the two heat transfer rotating frames 24 are connected by a guide rod 25, and the heat transfer rotating seat 22 slides up and down on the outer wall of the guide rod 25;

[0058] By providing the heat transfer bellows 17, the heat transfer bellows 17 can be more fully in contact with natural gas, thereby promoting the liquefaction of natural gas. The heat transfer bellows 17 restricts the rotation of the heat transfer rotating seat 22, but can automatically adjust the contact effect with natural gas according to the speed of the airflow. For example, when the airflow speed is too slow, the force driving the heat transfer blades 16 to move is small, and then the force pulling the heat transfer bellows 17 is small, so that the inclination of the heat transfer bellows 17 is small, and then a wider gap exists between the heat transfer bellows 17 for airflow to pass through; when the airflow speed is too fast, the pulling of the heat transfer bellows 17 is correspondingly intensified, so that the inclination of the heat transfer bellows 17 is increased, and the heat transfer rotating seat 22 slides downward along the outer wall of the guide rod 25 to match the inclination of the heat transfer bellows 17, so that the gap between the heat transfer bellows 17 is narrowed, so that it can be more fully in contact with natural gas; this method can well avoid the situation of insufficient cooling due to too fast airflow speed, thereby improving reliability.

[0059] To improve reliability; Figure 5 As shown, a ring frame 18 is installed on the outer side of one end of the support rod 14 close to the cooling cover 21, and the ring frame 18 and a heat transfer rotating frame 24 are connected through a spring 19;

[0060] By providing the clockwork spring 19, it is convenient to promote the heat transfer rotating seat 22 to reset when the air flow speed is slow, thereby improving reliability.

[0061] To improve reliability; Figure 1 , Figure 2 As shown, the input pipe is provided with a control valve 8 for controlling the on-off and opening degree of the input pipe;

[0062] By setting the control valve 8, it is possible to conveniently control the on-off and opening degree of the input pipe to meet actual needs. For example, when the air flow speed is too fast, or the pressure of the gas supply pipeline 7 is too high, the opening degree is increased, or the closed control valve 8 is opened, so that the natural gas can enter the liquefaction chamber 1 of other groups for liquefaction treatment. When the air flow speed is slow, part of the input pipe can be closed to put the corresponding liquefaction chamber 1 in a standby state.

[0063] Embodiment 2:

[0064] A staged natural gas liquefaction and purification device, such as Figure 1-6 As shown, this embodiment makes the following improvements on the basis of embodiment 1: the connecting pipeline includes:

[0065] A first delivery pipe 2, the first delivery pipe 2 is detachably connected to a gas outlet of a liquefaction chamber 1;

[0066] A second delivery pipe 13, the second delivery pipe 13 is detachably connected to the air inlet of another liquefaction chamber 1;

[0067] A third delivery pipe 10, one end of which is detachably connected to the first delivery pipe 2, and the other end of which is detachably connected to the second delivery pipe 13, and an air pump 11 is provided on the third delivery pipe 10;

[0068] By providing structures such as the first conveying pipe 2, the third conveying pipe 10 and the air pump 11, auxiliary conveying can be performed based on the operation of the air pump 11, thereby improving reliability.

[0069] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A hierarchical natural gas liquefaction and purification device, characterized in that: include: A gas supply pipeline (7), the gas supply pipeline (7) is connected to a natural gas supply system; A liquefaction chamber (1), wherein a gas outlet is arranged at the top of the liquefaction chamber (1), and a gas inlet is arranged at the bottom side of the liquefaction chamber (1). The liquefaction chamber (1) is arranged in multiple groups, and two adjacent liquefaction chambers (1) in each group are connected in series via a connecting pipeline to form a multi-stage liquefaction treatment structure; An input pipe, one end of which is connected to the gas supply pipeline (7), and the other end of which is connected to the gas inlet of the liquefaction chamber (1); an annular cover (15), the annular cover (15) being installed at equal distances in the liquefaction chamber (1), the cooling cover (21) being an inverted bucket-shaped structure with a middle portion bulging upward, and a first circulating cooling pipe (27) being installed in the annular cover (15); A cooling hood (21) is equidistantly arranged in the liquefaction chamber (1), and the cooling hood (21) and the annular hood (15) are staggered, the central axes of the liquefaction chamber (1), the cooling hood (21) and the annular hood (15) coincide, the middle portion of the cooling hood (21) bulges upward, a second circulating cooling pipe is installed in the cooling hood (21), and the first circulating cooling pipe (27) and the second circulating cooling pipe are both connected to a coolant circulating refrigeration system; the diameter of the bottom of the cooling hood (21) is greater than the inner diameter of the top of the annular hood (15).

2. A staged natural gas liquefaction and purification device according to claim 1, characterized in that: The bottom of the annular cover (15) is connected to an annular flow focusing frame (23) via a connecting rod, and an annular collection groove is formed between the annular flow focusing frame (23) and the inner wall of the liquefaction chamber (1), and the height of the annular collection groove gradually decreases towards a position away from the center of the liquefaction chamber (1); the annular cover (15) is provided with circumferentially distributed leakage openings (26), and the leakage openings (26) are located above the annular collection groove.

3. A hierarchical natural gas liquefaction and purification device according to claim 2, characterized in that: A first liquid discharge pipe (9) is arranged at the bottom of the liquefaction chamber (1), and a second liquid discharge pipe (12) is installed on the side of the liquefaction chamber (1). One end of the second liquid discharge pipe (12) passes through the liquefaction chamber (1) and is connected to the annular collection tank.

4. A staged natural gas liquefaction and purification device according to claim 3, characterized in that: Both ends of the first circulating cooling pipe (27) are connected to auxiliary pipes (20), one end of the auxiliary pipe (20) is connected to the circulating pipe (6), the top of the circulating pipe (6) is connected to a connecting seat (3), a connecting pipe (4) is installed on the connecting seat (3), the connecting pipe (4) is connected to the circulating liquid supply pipe (5), the circulating liquid supply pipe (5) is connected to the coolant circulating refrigeration system, and the circulating pipe (6) is connected to the connecting pipe (4) after passing through the internal passage of the connecting seat (3); a support rod (14) is installed on the top of the cooling cover (21), the support rod (14) passes through the liquefaction chamber (1) and is connected to the connecting seat (3), and both ends of the second circulating cooling pipe are connected to the connecting seat (3) after passing through the liquid supply passage of the support rod (14).

5. A staged natural gas liquefaction and purification device according to claim 4, characterized in that: An annular plate is arranged on the outside of the cooling cover (21), a heat transfer rotating frame (24) is rotatably mounted on the outside of the annular plate, a heat transfer rotating seat (22) is mounted on the heat transfer rotating frame (24), and circumferentially distributed heat transfer blades (16) are arranged on the outside of the heat transfer rotating seat (22); a guide pipe (30) is arranged at the bottom of the cooling cover (21), the top end of the guide pipe (30) is connected to the top of the cooling cover (21), and the bottom end of the guide pipe (30) extends to above the annular cover (15).

6. A staged natural gas liquefaction and purification device according to claim 5, characterized in that: The inner side of the heat transfer rotating frame (24) and the outer side of the annular plate are both provided with matching annular grooves, and a plurality of balls (29) are movably installed in the annular grooves.

7. A staged natural gas liquefaction and purification device according to claim 6, characterized in that: An annular heat transfer frame (28) is fixed on the top of the annular cover (15), and a plurality of circumferentially distributed heat transfer bellows (17) are fixed on the top of the annular heat transfer frame (28), and one end of the heat transfer bellows (17) is fixed to the bottom of the heat transfer blade (16); two heat transfer rotating frames (24) are respectively arranged on the upper and lower sides of the heat transfer rotating seat (22), and the two heat transfer rotating frames (24) are connected by a guide rod (25), and the heat transfer rotating seat (22) slides up and down on the outer wall of the guide rod (25).

8. A staged natural gas liquefaction and purification device according to claim 7, characterized in that: An annular frame (18) is installed on the outer side of one end of the support rod (14) close to the cooling cover (21), and the annular frame (18) and a heat transfer rotating frame (24) are connected via a spring (19).

9. A staged natural gas liquefaction and purification device according to claim 1, characterized in that: The input pipe is provided with a control valve (8) for controlling the on / off and opening degree of the input pipe.

10. The staged natural gas liquefaction and purification device according to claim 1, characterized in that: The connecting pipeline comprises: A first delivery pipe (2), the first delivery pipe (2) being detachably connected to a gas outlet of a liquefaction chamber (1); A second delivery pipe (13), the second delivery pipe (13) being detachably connected to the gas inlet of another liquefaction chamber (1); A third delivery pipe (10), one end of the third delivery pipe (10) is detachably connected to the first delivery pipe (2), the other end of the third delivery pipe (10) is detachably connected to the second delivery pipe (13), and an air pump (11) is provided on the third delivery pipe (10).

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