A high-efficiency energy-saving air separation unit and control method thereof

Abstract

The present invention relates to the field of air separation technology, and more specifically, to a high-efficiency and energy-saving air separation device and a control method thereof. The device comprises a heat exchange tank and a bracket for supporting the heat exchange tank. A feed port and a discharge port communicating with the interior of the heat exchange tank are provided on both sides of the heat exchange tank. A plurality of cooling tubes are provided in the heat exchange tank between the feed port and the discharge port, and the heat exchange tank is provided with an air inlet pipe and a liquid discharge pipe. A memory spring is used to automatically adjust the space inside the movable plate and the fixed plate according to the flow rate of incoming air. When the air channel spacing between the movable plate and the adjacent baffle is reduced, the space inside the fixed plate and the movable plate increases. At this time, the movable plate and the fixed plate act like pistons to draw air from the interior of the heat exchange tank. The air stays in the fixed plate and the movable plate. While the cooling tubes continue to provide cooling, the air's residence time is extended, allowing the air and cooling tube to have more time to exchange heat, thereby improving the overall heat exchange efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of air separation, in particular to a high-efficiency energy-saving air separation device and a control method thereof. Background Art

[0002] An air separation unit uses air as raw material, converts the air into liquid, and then through distillation, gradually separates and produces inert gases such as oxygen, nitrogen and argon from the liquid air.

[0003] There are many existing technologies for air separation units, such as:

[0004] Chinese patent publication number CN115031490B discloses an energy-saving liquefied natural gas (LNG) cold energy air separation system, which relates to the technical field of air separation devices. The system includes an air storage tank, an air purification unit, an LNG refrigeration unit, and a heat exchanger. The air storage tank is connected to the air purification unit and is used to provide air raw material for the air purification unit; the air purification unit is used to purify the air and input the purified air into the heat exchanger; and the LNG refrigeration unit is used to input cold energy into the heat exchanger. This application can improve the energy exchange efficiency between air and natural gas cold energy.

[0005] It can be seen from this that in the existing technology, in order to improve the energy exchange efficiency between air and natural gas cold energy, air is usually passed through a pre-set disc-shaped curved pipe to increase the time the air flows in the heat exchange tank. However, when the speed of the incoming air is greater than the speed provided by the cold energy, the redundant air will flow along the "S-shaped" route to the feed end of the cold energy, and then absorb the cold energy at the feed end, causing the temperature of the cold energy flowing from the feed end to the discharge end to increase, resulting in a decrease in the effect of air liquefaction and the energy exchange efficiency between air and cold energy. Summary of the Invention

[0006] The object of the present invention is to provide a high-efficiency and energy-saving air separation unit and a control method thereof to solve the problems raised in the above background technology.

[0007] In order to achieve the above-mentioned object, the present invention aims to provide a high-efficiency and energy-saving air separation device, including a heat exchange tank and a bracket for supporting the heat exchange tank, a feed port and a discharge port connected to the interior of the heat exchange tank are arranged on both sides of the heat exchange tank, a plurality of cooling pipes are arranged in the heat exchange tank between the feed port and the feed port, and an air inlet pipe and a liquid discharge pipe are arranged on the heat exchange tank, a plurality of baffles are arranged horizontally from the discharge port to the feed port in the direction of the horizontal upper and lower intervals inside the heat exchange tank, the plurality of baffles are arranged at intervals so that the air path entering the heat exchange tank forms an "S" shape, and a pair of baffles are arranged inside the heat exchange tank near the air inlet pipe. An air guide mechanism is provided for guiding the air entering the heat exchange tank. The air guide mechanism includes a fixed plate fixedly connected to the inner wall of the heat exchange tank and a movable plate sleeved on the outside of the fixed plate. A temperature sensing mechanism for controlling the movement of the movable plate is provided between the fixed plate and the movable plate. When the temperature of the cold water in the cold water pipe located in the fixed plate and the movable plate decreases, the temperature sensing mechanism is utilized to move the movable plate closer to the baffle. The movable plate is used to narrow the gap in the channel for air circulation, thereby reducing the speed of air flowing inside the heat exchange tank, and expanding the internal space of the fixed plate and the movable plate so that the cold water pipe is in full contact with the air.

[0008] As a further improvement of the present technical solution, the outer ring of the side of the fixed plate is fixedly connected to the inner wall of the heat exchange tank, the side of the fixed plate is vertically away from the connection between the air inlet pipe and the heat exchange tank, and the fixed plate is slidingly connected to the movable plate, the cold pipe passes through the fixed plate and the movable plate, and a plurality of air inlet holes are provided on the side of the fixed plate close to the air inlet pipe, and an outer air guide plate for guiding the air to the cold pipe is symmetrically arranged inside the fixed plate, so that the air contacts the cold pipe and is liquefied.

[0009] As a further improvement of the present technical solution, the side wall of the fixed plate is fixedly connected to a partition with the same radius as the fixed plate, and the partition divides the air intake pipe into two. A front through hole is provided at the bottom of the fixed plate near the side of the fixed plate, and a circular hole is provided on the movable plate corresponding to the front through hole. Under normal circumstances, the front through hole coincides with the circular hole. When air enters the heat exchange tank, the air is divided into two streams. One stream enters the fixed plate and the movable plate from the air intake hole, and is discharged from the circular hole through the front through hole. The other stream of air flows along an "S" shaped route.

[0010] As a further improvement of the present technical solution, a return pipe is provided on the heat exchange tank near the feed port to connect the heat exchange tank with the air inlet pipe. A first one-way valve is provided at the connection between the return pipe and the air inlet pipe. The return pipe is used to guide air to the air inlet pipe and into the heat exchange tank to realize the recycling of air.

[0011] As a further improvement of the present technical solution, an upper air guide plate is fixedly connected to the top of the inner wall of the fixed plate, and one end of the upper air guide plate close to the movable plate is tilted downward, and the other end is tilted upward to guide the incoming air to the cooling tube, and the upper air guide plate and the outer air guide plate together form an air guide channel, and a drain pipe is connected to the bottom of the heat exchange tank, and the two pipe openings of the drain pipe are located on both sides of the fixed plate and the movable plate close to the discharge port and in an inverted state, and the other pipe opening is connected to the drain pipe.

[0012] As a further improvement of the present technical solution, an inner air guide plate fixedly connected to the movable plate is provided on the inner side of the outer air guide plate. When the movable plate moves, the outer air guide plate and the inner air guide plate cooperate to guide the air to the cooling tube.

[0013] As a further improvement of the present technical solution, the temperature sensing mechanism includes a memory spring symmetrically arranged between the fixed plate and the movable plate, wherein the memory spring is in a compressed state at the initial temperature inside the fixed plate and the movable plate, and is in an elongated state when the temperature is lower than the initial temperature. One end of the memory spring is fixedly connected to the inner wall of the fixed plate, and the other end is fixedly connected to the inner wall of the movable plate. The movable plate is fitted with the bottom end of the inner wall of the fixed plate, and the movable plate is sleeved on the telescopic rod connecting the fixed plate and the movable plate.

[0014] As a further improvement of the present technical solution, a rear through hole is provided at the bottom of the fixed plate near the movable plate, and a second one-way valve for discharging air and water droplets is provided in the front through hole and the rear through hole. When the rear through hole coincides with the circular hole, the air and water droplets in the fixed plate and the movable plate are discharged vertically downward from the fixed plate and the movable plate, forming a barrier that delays the flow of air outside the fixed plate and the movable plate.

[0015] The second object of the invention is to provide a control method for operating the above-mentioned high-efficiency energy-saving air separation unit, comprising the following method steps:

[0016] S1. When the air is exchanging heat with the cold energy, the air in the air storage tank is transported to the air purification device, and then the air purification device purifies the air. The air purification device is connected to the air intake pipe and transports the purified air to the heat exchange tank;

[0017] S2. At the same time, the feed port and the discharge port are both connected to the LNG refrigeration device to form a cold cycle. The LNG refrigeration device inputs cold energy into the cold pipe in the heat exchange tank, so that the air in the heat exchange tank can be liquefied. The multiple baffles are arranged at intervals so that the air path entering the heat exchange tank forms an "S" shape. When the temperature in the air guide mechanism decreases, the external air is dispersed into the interior of the air guide mechanism to slow down the air flow speed and increase the contact time between the air and the cold chain pipe.

[0018] S3. The heat exchange tank then inputs the liquefied air into a distillation device connected to the discharge pipe, so that the distillation device can separate the oxygen and nitrogen in the liquid air.

[0019] Compared with the prior art, the present invention has the following beneficial effects:

[0020] 1. In this high-efficiency and energy-saving air separation unit, a memory spring is used to automatically adjust the space inside the movable plate and the fixed plate according to the flow rate of incoming air. When the movable plate approaches the baffle, the air channel spacing between the movable plate and the adjacent baffle is reduced, and the air flow rate per unit time is reduced. As the movable plate moves toward the baffle, the space inside the fixed plate and the movable plate increases, and the front through hole and the circular hole are misaligned. At this time, the movable plate and the fixed plate draw air from the heat exchange tank in the form of a piston, and the air stays in the fixed plate and the movable plate. When the cooling tube continues to provide cooling, the air residence time is extended, allowing the air and the cooling tube to have more time for heat exchange, thereby improving the overall heat exchange efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the overall structure of the present invention;

[0022] Figure 2 This is a schematic diagram of the internal structure of the heat exchange tank of the present invention;

[0023] Figure 3 This is a schematic diagram of the explosion structure of the fixed plate and the movable plate of the present invention;

[0024] Figure 4 It is a left side view of the internal structure of the movable panel of the present invention;

[0025] Figure 5 It is a front view of the internal structure of the fixed plate and the movable plate of the present invention;

[0026] Figure 6 This is a schematic diagram of the structure of the movable plate moving toward the baffle of the present invention;

[0027] Figure 7 For the present invention Figure 6 A in the figure is an enlarged structural diagram.

[0028] The meaning of each number in the figure is:

[0029] 100, heat exchange tank; 101, bracket; 102, feed port; 103, discharge port; 104, air inlet pipe; 105, drain pipe;

[0030] 110, air guide mechanism; 110a, baffle; 111, fixed plate; 111a, outer air guide plate; 112, movable plate; 112a, inner air guide plate; 113, air inlet; 114, upper air guide plate; 115, partition;

[0031] 120. Temperature sensing mechanism; 121. Memory spring; 122. Telescopic rod;

[0032] 130, round hole;

[0033] 140, front through hole; 141, rear through hole;

[0034] 150. Return pipe; 160. Drain pipe. DETAILED DESCRIPTION

[0035] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0036] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0037] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0038] like Figure 1 、 Figure 2As shown, a high-efficiency and energy-saving air separation device is provided, including a heat exchange tank 100 and a bracket 101 for supporting the heat exchange tank 100. A feed port 102 and a discharge port 103 connected to the interior of the heat exchange tank 100 are provided on both sides of the heat exchange tank 100. There are multiple cooling pipes in the heat exchange tank 100 between the feed port 102 and the feed port 102, and an air inlet pipe 104 and a liquid discharge pipe 105 are provided on the heat exchange tank 100. In combination with the existing technology, it can be known that when the air and the cold energy are heat exchanged, the air in the air storage tank is transported to the air purification device, and then the air purification device purifies the air. The air purification device is connected to the air inlet pipe 104 and transports the purified air to the heat exchange tank 100. At the same time, the feed port 102 and the discharge port 103 are both connected to the LNG refrigeration device to form a cold energy cycle. The LNG refrigeration device inputs cold energy into the cold energy pipe in the heat exchange tank 100, so that the air in the heat exchange tank 100 can be liquefied, and then the heat exchange tank 100 inputs the liquefied air into the distillation device connected to the discharge pipe 105, so that the distillation device can separate the oxygen and nitrogen in the liquid air.

[0039] However, when the air velocity entering the heat exchange tank 100 is greater than the velocity of the cold energy provided by the cold energy pipe, the redundant air will flow along the "S-shaped" route inside the heat exchange tank 100 to the feed end of the cold energy (i.e., the feed port 102), and then absorb the cold energy at the feed end, causing the temperature of the cold energy flowing from the feed end to the discharge end to increase, resulting in the effect of air liquefaction at the discharge end and the energy exchange efficiency between air and cold energy to decrease.

[0040] To this end, combined Figure 2 、 Figure 4 and Figure 6 As shown, a plurality of baffles 110a are arranged horizontally and spaced apart from each other in the direction from the discharge port 103 to the feed port 102 inside the heat exchange tank 100. The plurality of baffles 110a are arranged at intervals so that the air path entering the heat exchange tank 100 forms an "S" shape. An air guide mechanism 110 for guiding the air entering the heat exchange tank 100 is provided inside the heat exchange tank 100 near the air inlet pipe 104. The air guide mechanism 110 includes a fixed plate 111 fixedly connected to the inner wall of the heat exchange tank 100 and a movable plate 112 sleeved on the outside of the fixed plate 111. The fixed plate 111 and the movable plate 112 are arranged at intervals so that the air path entering the heat exchange tank 100 forms an "S" shape. A temperature sensing mechanism 120 is provided between the plates 112 for controlling the movement of the movable plate 112. When the temperature of the cold water in the cold water pipe located between the fixed plate 111 and the movable plate 112 decreases, the temperature sensing mechanism 120 is utilized to move the movable plate 112 closer to the baffle 110a. The movable plate 112 is used to narrow the channel gap for air circulation, thereby reducing the speed of air flowing inside the heat exchange tank 100, and expanding the internal space of the fixed plate 111 and the movable plate 112 so that the cold water pipe is in full contact with the air, thereby improving the contact time between the air and the cold water pipe and the energy exchange efficiency.

[0041] Therefore, based on the above structure, combined with Figure 3 The figure further discloses the structure of the fixed plate 111 and the movable plate 112. The outer ring of the side of the fixed plate 111 is fixedly connected to the inner wall of the heat exchange tank 100. The side of the fixed plate 111 is vertically away from the connection between the air inlet pipe 104 and the heat exchange tank 100, and the fixed plate 111 is slidingly connected to the movable plate 112. The cold pipe passes through the fixed plate 111 and the movable plate 112. A plurality of air inlet holes 113 are provided on the side of the fixed plate 111 close to the air inlet pipe 104. The fixed plate 111 is symmetrically provided with an outer air guide plate 111a for guiding air to the cold pipe, so that the air contacts the cold pipe and is liquefied.

[0042] On the other hand, a partition 115 with the same radius as the fixed plate 111 is fixedly connected to the side wall of the fixed plate 111, and the partition 115 divides the air intake pipe 104 into two. A front through hole 140 is provided at the bottom of the fixed plate 111 near the side of the fixed plate 111, and a circular hole 130 is provided on the movable plate 112 corresponding to the front through hole 140. Under normal circumstances, the front through hole 140 coincides with the circular hole 130. When air enters the heat exchange tank 100, the air is divided into two streams. One stream enters the fixed plate 111 and the movable plate 112 from the air intake hole 113, and is discharged from the circular hole 130 through the front through hole 140. The other stream of air flows along an "S" shaped route.

[0043] That is to say, when the air entering the heat exchange tank 100 is at a small flow rate, the air mainly flows along an "S"-shaped route, and part of the air will enter the fixed plate 111 and the movable plate 112 from the air inlet 113, and under the action of the outer air guide plate 111a, the outer air guide plate 111a guides the air to the cold pipe, so that the air liquefies and forms water droplets after passing through the cold pipe. The formed water droplets and the air passing through the cold pipe flow through the front through hole 140 and are discharged from the circular hole 130. The water droplets are stored at the bottom end of the inner wall of the heat exchange tank 100, and the air discharged from the circular hole 130 is blown toward the other air, thereby inhibiting the other air, slowing down the air flow rate, and increasing the contact time between the air and the rear end cold pipe.

[0044] It is worth noting that: when the air inside the heat exchange tank 100 enters at a small flow rate, at this time, since the cold energy in the cold energy pipe can continuously provide cold energy, the cold energy in the cold energy pipe located at the feed port 102 can be continuously transported toward the discharge port 103, and the cold energy temperature in the cold energy pipe located near the feed port 102 remains stable.

[0045] Furthermore, when the air inside the heat exchange tank 100 enters at a large flow rate, the redundant air will cause the feed port 102 to come into contact with the cold air in the cold water pipe located at the feed port 102, causing the temperature of the cold air in the cold water pipe at this position to rise, and the cold air with increased temperature will continue to be transported to the discharge port 103 in the cold water pipe. Then, for the air at the rear end away from the feed port 102 that has not yet been liquefied or has just entered the heat exchange tank 100, the temperature increase will reduce the effect of air liquefaction, resulting in the redundant air being discharged to the outside, causing waste.

[0046] So, returning to Figure 2 As shown, when the redundant air arrives near the feed port 102, a return pipe 150 is provided on the heat exchange tank 100 near the feed port 102 to connect the heat exchange tank 100 with the air inlet pipe 104, and a first one-way valve is provided at the connection between the return pipe 150 and the air inlet pipe 104. The return pipe 150 is used to guide the air to the air inlet pipe 104 and enter the heat exchange tank 100 to realize the recycling of air, that is, the redundant air enters from one end of the return pipe 150 and then flows back to the inside of the heat exchange tank 100, so that the air that has not yet been liquefied is recycled. In this way, the energy consumption of the purification device can be reduced and the utilization rate of the air can be improved.

[0047] In order to prevent air from being discharged from the drain pipe 105 , a corresponding valve may be provided between the drain pipe 105 and the external distillation device to restrict the air in the heat exchange tank 100 .

[0048] Below Figure 2 Based on and combined with Figure 5 、 Figure 6 As shown, an upper air guide plate 114 is fixedly connected to the top of the inner wall of the fixed plate 111. One end of the upper air guide plate 114, near the movable plate 112, is tilted downward, while the other end is tilted upward to guide the incoming air toward the cooling tube. The upper air guide plate 114 and the outer air guide plate 111a together form an air guide channel. A drain pipe 160 is connected to the bottom of the heat exchange tank 100. Two outlets of the drain pipe 160 are located on either side of the inverted fixed plate 111 and movable plate 112 near the discharge port 103, and the other outlet is connected to the drain pipe 105. After the heat exchange between the air and the cooling tube is completed, the valve is opened, and the liquefied water droplets inside the heat exchange tank 100 are discharged from the drain pipe 105 to the distillation device, which can separate the oxygen and nitrogen in the liquid air.

[0049] Moreover, considering that the incoming air can be ensured to move toward the cooling tube during the separation of the movable plate 112 from the fixed plate 111, an inner air guide plate 112a fixedly connected to the movable plate 112 is provided on the inner side of the outer air guide plate 111a. When the movable plate 112 moves, the outer air guide plate 111a and the inner air guide plate 112a cooperate to guide the air toward the cooling tube.

[0050] In addition, when the air inside the heat exchange tank 100 enters at a large flow rate, the amount of air entering the fixed plate 111 and the movable plate 112 from the air inlet 113 increases. At this time, the air is liquefied into water droplets after passing through the cold pipe. At the same time, the temperature of the excess air decreases when passing through the cold pipe. Since the temperature sensing mechanism 120 includes a memory spring 121 symmetrically arranged between the fixed plate 111 and the movable plate 112, wherein the memory spring 121 has a two-way memory function, the martensite phase (parent phase (phase structure at high temperature) of the memory spring 121 is the initial temperature of the fixed plate 111 and the movable plate 112 when the air enters the fixed plate 111 and the movable plate 112 at a large flow rate. ) is a hard phase, that is, a compressed state, (the phase structure at low temperature, the low temperature here refers to a phase structure lower than the initial temperature inside the fixed plate 111 and the movable plate 112) is a soft phase, that is, an elongated state. The specific temperature depends on the material used for the memory spring 121. The memory spring 121 is in a compressed state at the initial temperature inside the fixed plate 111 and the movable plate 112, and is in an elongated state when the temperature is lower than the initial temperature. One end of the memory spring 121 is fixedly connected to the inner wall of the fixed plate 111, and the other end is fixedly connected to the inner wall of the movable plate 112. The movable plate 112 is in contact with the bottom end of the inner wall of the fixed plate 111, and the movable plate 112 is sleeved on the telescopic rod 122 connecting the fixed plate 111 and the movable plate 112.

[0051] In this way, when the air passes through the air inlet 113 at a large flow rate, the large flow rate of air will generate more water droplets in the fixed plate 111 and the movable plate 112 compared to when the air passes through the air inlet 113 at a small flow rate. The air needs to be cooled to liquefy into water droplets, that is, the temperature of the liquefied water droplets is low. Combined with the redundant air, the temperature drops after passing through the cooling tube, causing the memory spring 121 to push the movable plate 112 outward. As the movable plate 112 approaches the baffle 110a, the air channel spacing between the movable plate 112 and the adjacent baffle 110a is reduced, and the air in the unit time is reduced. The air flow rate is reduced. When the movable plate 112 moves toward the baffle 110a, the space inside the fixed plate 111 and the movable plate 112 increases, and the front through hole 140 is misaligned with the circular hole 130. At this time, the movable plate 112 and the fixed plate 111 draw the air inside the heat exchange tank 100 in the form of a piston. The air stays in the fixed plate 111 and the movable plate 112. When the cooling tube continues to provide cooling, the air residence time is extended, allowing the air and the cooling tube to have more time to exchange heat, thereby improving the overall heat exchange efficiency.

[0052] It should be noted that although a small flow of air will also generate water droplets in the fixed plate 111 and the movable plate 112 , the amount of air entering the fixed plate 111 and the movable plate 112 is small, and the phenomenon that the memory spring 121 is in an extended state is not obvious.

[0053] exist Figure 5 Based on and combined with Figure 7 As shown, because a rear through hole 141 is provided at the bottom of the fixed plate 111 near the movable plate 112, a second one-way valve for discharging air and water droplets is provided in the front through hole 140 and the rear through hole 141. When the rear through hole 141 coincides with the circular hole 130, the air and water droplets in the fixed plate 111 and the movable plate 112 are discharged vertically downward from the fixed plate 111 and the movable plate 112, forming a barrier that delays the flow of air outside the fixed plate 111 and the movable plate 112.

[0054] That is to say, as the air flow rate increases, more water droplets are formed by liquefying the air, and the air with a lowered temperature after passing through the cooling tube comes into contact with the memory spring 121. The memory spring 121 gradually stretches, causing the rear through hole 141 and the circular hole 130 to be misaligned, so that the external air stays in the fixed plate 111 and the movable plate 112.

[0055] The above shows and describes the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely preferred examples of the present invention and are not intended to limit the present invention. Various changes and improvements may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and improvements fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A high-efficiency energy-saving air separation unit, comprising a heat exchange tank (100) and a bracket (101) for supporting the heat exchange tank (100), wherein a feed port (102) and a discharge port (103) communicating with the interior of the heat exchange tank (100) are provided on both sides of the heat exchange tank (100), a plurality of cooling pipes are provided in the heat exchange tank (100) between the feed port (102) and the discharge port (103), and an air inlet pipe (104) and a liquid discharge pipe (105) are provided on the heat exchange tank (100), characterized in that: A plurality of baffles (110a) are horizontally arranged vertically in a direction from the discharge port (103) to the feed port (102) inside the heat exchange tank (100). The plurality of baffles (110a) are arranged at intervals so that the air path entering the heat exchange tank (100) forms an "S" shape. An air guide mechanism (110) for guiding the air entering the heat exchange tank (100) is arranged inside the heat exchange tank (100) near the air inlet pipe (104). The air guide mechanism (110) includes a fixed plate (111) fixedly connected to the inner wall of the heat exchange tank (100) and a movable plate (111) sleeved on the outside of the fixed plate (111). 112), a temperature sensing mechanism (120) for controlling the movement of the movable plate (112) is provided between the fixed plate (111) and the movable plate (112). When the temperature of the cold water in the cold water pipes located in the fixed plate (111) and the movable plate (112) decreases, the temperature sensing mechanism (120) is used to move the movable plate (112) closer to the baffle (110a). The movable plate (112) is used to narrow the gap in the channel for air circulation, thereby reducing the speed of air flowing inside the heat exchange tank (100), and the internal space of the fixed plate (111) and the movable plate (112) is expanded, so that the cold water pipe is fully in contact with the air.

2. The high-efficiency energy-saving air separation unit according to claim 1, characterized in that: The outer ring of the side of the fixed plate (111) is fixedly connected to the inner wall of the heat exchange tank (100), the side of the fixed plate (111) is vertically away from the connection between the air inlet pipe (104) and the heat exchange tank (100), and the fixed plate (111) is slidably connected to the movable plate (112), the cold pipe passes through the fixed plate (111) and the movable plate (112), a plurality of air inlet holes (113) are provided on one side of the fixed plate (111) close to the air inlet pipe (104), and an outer air guide plate (111a) for guiding air to the cold pipe is symmetrically arranged inside the fixed plate (111), so that the air contacts the cold pipe and is liquefied.

3. The high-efficiency energy-saving air separation unit according to claim 1, characterized in that: The side wall of the fixed plate (111) is fixedly connected to a partition (115) having the same radius as the fixed plate (111). The partition (115) divides the air inlet pipe (104) into two. A front through hole (140) is provided at the bottom of the fixed plate (111) near the side of the fixed plate (111). A circular hole (130) is provided on the movable plate (112) corresponding to the front through hole (140). Under normal conditions, the front through hole (140) and the circular hole (130) coincide with each other. When air enters the heat exchange tank (100), the air is divided into two streams. One stream enters the fixed plate (111) and the movable plate (112) from the air inlet hole (113), passes through the front through hole (140), and is discharged from the circular hole (130). The other stream of air flows along an "S"-shaped route.

4. The high-efficiency energy-saving air separation unit according to claim 1, characterized in that: A return pipe (150) is provided on the heat exchange tank (100) near the feed port (102) to connect the heat exchange tank (100) with the air inlet pipe (104). A first one-way valve is provided at the connection between the return pipe (150) and the air inlet pipe (104). The return pipe (150) is used to guide air to the air inlet pipe (104) and into the heat exchange tank (100), so as to achieve air recycling.

5. The high-efficiency energy-saving air separation unit according to claim 1, characterized in that: An upper air guide plate (114) is fixedly connected to the top of the inner wall of the fixed plate (111), and one end of the upper air guide plate (114) close to the movable plate (112) is tilted downward, and the other end is tilted upward to guide the incoming air to the cooling tube, and the upper air guide plate (114) and the outer air guide plate (111a) together form an air guide channel. A drainage pipe (160) is connected to the bottom of the heat exchange tank (100), and two pipe openings of the drainage pipe (160) are located on both sides of the fixed plate (111) and the movable plate (112) in an inverted state near the discharge port (103), and the other pipe opening is connected to the drain pipe (105).

6. The high-efficiency energy-saving air separation unit according to claim 5, characterized in that: An inner air guide plate (112a) fixedly connected to the movable plate (112) is provided on the inner side of the outer air guide plate (111a); when the movable plate (112) moves, the outer air guide plate (111a) cooperates with the inner air guide plate (112a) to guide air toward the cooling tube.

7. The high-efficiency energy-saving air separation unit according to claim 1, characterized in that: The temperature sensing mechanism (120) includes a memory spring (121) symmetrically arranged between the fixed plate (111) and the movable plate (112), wherein the memory spring (121) is in a compressed state at an initial temperature inside the fixed plate (111) and the movable plate (112), and is in an extended state when the temperature is lower than the initial temperature. One end of the memory spring (121) is fixedly connected to the inner wall of the fixed plate (111), and the other end is fixedly connected to the inner wall of the movable plate (112). The movable plate (112) is fitted with the bottom end of the inner wall of the fixed plate (111), and the movable plate (112) is sleeved on the telescopic rod (122) connecting the fixed plate (111) and the movable plate (112).

8. The high-efficiency energy-saving air separation unit according to claim 3, characterized in that: A rear through hole (141) is provided at the bottom of the fixed plate (111) near the movable plate (112), and a second one-way valve for discharging air and water droplets is provided in both the front through hole (140) and the rear through hole (141). When the rear through hole (141) coincides with the circular hole (130), the air and water droplets in the fixed plate (111) and the movable plate (112) are discharged vertically downward from the fixed plate (111) and the movable plate (112), thereby forming a barrier that delays the flow of air outside the fixed plate (111) and the movable plate (112).

9. A control method for operating a high-efficiency energy-saving air separation unit according to any one of claims 1 to 8, characterized in that: The method comprises the following steps: S1. When the air is exchanging heat with the cold, the air in the air storage tank is transported to the air purification device, which then purifies the air. The air purification device is connected to the air inlet pipe (104) and transports the purified air to the heat exchange tank (100); S2. At the same time, the feed port (102) and the discharge port (103) are both connected to the LNG refrigeration device to form a cold cycle. The LNG refrigeration device inputs cold energy into the cold pipe in the heat exchange tank (100), so that the air in the heat exchange tank (100) can be liquefied. The plurality of baffles (110a) are arranged at intervals so that the air path entering the heat exchange tank (100) forms an "S" shape. When the temperature in the air guide mechanism (110) decreases, the external air is dispersed into the inside of the air guide mechanism (110) to slow down the speed of the air flow and increase the time the air is in contact with the cold chain pipe. S3. The heat exchange tank (100) then inputs the liquefied air into a distillation device connected to the liquid discharge pipe (105), so that the distillation device can separate the oxygen and nitrogen in the liquid air.

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