U-shaped bent pipeline for liquid nitrogen extraction

Abstract

The utility model belongs to the technical field of fractionating tower extraction pipelines, and relates to a liquid nitrogen extraction U-shaped bent pipeline which comprises a cold box, a fractionating tower is arranged in the cold box, a liquid nitrogen pipeline is led out of the top of the fractionating tower, the liquid nitrogen pipeline extends out of the cold box and is connected to a draw-off pump, and the rear side of the draw-off pump is connected to a conveying pipeline and is connected to a storage tank. The shape of the pipeline is designed, cold running and frosting caused by low-temperature liquid are avoided, the pressure in the fractionating tower cannot be influenced, and the rectification working condition is stable.

Description

Technical Field

[0001] The utility model belongs to the technical field of fractionation tower extraction pipelines, and in particular relates to a liquid nitrogen extraction U-shaped bent pipeline. Background Art

[0002] The distillation tower is used to separate the mixture into different components according to their boiling point differences. The extraction pipeline is responsible for extracting these different components from the distillation tower and transporting them to subsequent process flows or storage devices. The liquid or gas inside the distillation tower is gradually separated in different trays or packing layers. The temperature and pressure of each tray or layer are different, resulting in different components being separated at their own specific heights. The extraction pipeline extracts these components from each corresponding height.

[0003] The liquid nitrogen separated by the distillation tower flows along the pipeline to the outside of the cold box. The low-temperature pipeline will condense the moisture in the air on the pipe wall. The liquid nitrogen discharge pipeline has no problem in summer operation, but will frost in the cold winter, increasing the pressure inside the tower and affecting the distillation effect of the distillation tower. Therefore, a U-bend pipeline for liquid nitrogen extraction is proposed. Utility Model Content

[0004] The utility model aims to provide a liquid nitrogen extraction U-shaped bend pipeline, which has a liquid nitrogen extraction anti-frost function and solves the problem of frosting of liquid nitrogen discharge in the prior art.

[0005] In order to achieve the above-mentioned purpose, the technical solution adopted by the utility model is as follows: the utility model provides a liquid nitrogen extraction U-shaped bend pipeline, including a cold box, a fractionation tower is arranged inside the cold box, a liquid nitrogen pipeline is led out from the top of the fractionation tower, the liquid nitrogen pipeline extends to the outside of the cold box, the liquid nitrogen pipeline is connected to an extraction pump, and the rear side of the extraction pump is connected to a delivery pipeline connected to a storage tank.

[0006] Preferably, the liquid nitrogen pipeline is Z-shaped, the delivery pipeline is L-shaped, and the liquid nitrogen pipeline is connected to the delivery pipeline through an extraction pump to form an overall U-shape.

[0007] Preferably, a fixing plate is provided at the connection between the liquid nitrogen pipeline and the cold box.

[0008] Preferably, the liquid nitrogen pipeline has a diameter of 15 mm, a wall thickness of 2.11 mm, and is made of aluminum alloy.

[0009] Preferably, the transverse length of the liquid nitrogen pipeline is 1000 mm.

[0010] Preferably, a liquid nitrogen valve is provided on the liquid nitrogen pipeline.

[0011] Compared with the prior art, the advantages and positive effects of the utility model are:

[0012] 1. The pipeline shape design of the utility model can avoid the cold liquid from frost formation, the pressure inside the distillation tower will not be affected, and the distillation working condition is stable;

[0013] 2. The utility model has the function of preventing frosting when extracting liquid nitrogen, which solves the problem of frosting in the prior art of liquid nitrogen discharge. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the following is a brief introduction to the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative labor.

[0015] Figure 1 It is a structural schematic diagram of a liquid nitrogen extraction U-shaped bend pipeline;

[0016] In the above figure, 1. cold box, 2. distillation tower, 3. liquid nitrogen pipeline, 4. extraction pump, 5. liquid nitrogen valve, 6. delivery pipeline, 7. storage tank, 8. fixed plate. DETAILED DESCRIPTION

[0017] In order to more clearly understand the above-mentioned purpose, features and advantages of the utility model, the utility model is further described below in conjunction with the accompanying drawings and embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0018] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways than those described herein. Therefore, the present invention is not limited to the specific embodiments of the following disclosure.

[0019] Embodiment 1, as Figure 1 As shown, a liquid nitrogen extraction U-bend pipeline includes a cold box 1, which is used to maintain an internal low temperature environment to ensure the stability of the fractionation tower 2 and the liquid nitrogen therein. The cold box 1 can effectively isolate the influence of external heat, prevent the temperature of the liquid nitrogen from rising during transportation, and ensure the efficiency of the entire fractionation process.

[0020] The cold box 1 is provided with a fractionation tower 2, which is used to separate mixed gases such as air according to their boiling point differences. The temperature and pressure differences at different heights in the fractionation tower 2 allow components such as liquid nitrogen to be extracted at specific locations, and high-purity liquid nitrogen can be extracted through the fractionation tower 2. A liquid nitrogen pipeline 3 is led out from the top of the fractionation tower 2, and the liquid nitrogen pipeline 3 extends to the outside of the cold box 1. The liquid nitrogen pipeline 3 is responsible for leading the liquid nitrogen extracted from the top of the fractionation tower 2 to the outside of the cold box 1.

[0021] The liquid nitrogen pipeline 3 is connected to the extraction pump 4, and the rear side of the extraction pump 4 is connected to the delivery pipeline 6 connected to the storage tank 7. The storage tank 7 is used to store the liquid nitrogen extracted from the distillation tower 2 for subsequent use. The storage tank 7 can effectively isolate the external temperature changes, maintain the stable state of the liquid nitrogen, and avoid sublimation and pressure fluctuations. The extraction pump 4 is used to transport the liquid nitrogen in the cold box 1 to the external storage tank 7 through the liquid nitrogen pipeline 3, providing sufficient power to ensure the smooth flow of liquid nitrogen and maintain the pressure balance inside the system.

[0022] The following is a detailed description of the design of the above key components:

[0023] The liquid nitrogen pipeline 3 is Z-shaped. The liquid nitrogen pipeline 3 is designed in a Z shape. The Z shape can effectively reduce the flow resistance of liquid nitrogen in the pipeline and prevent the heat exchange caused by low-temperature liquid nitrogen in the pipeline from causing frosting. The Z-shaped design can effectively prevent the cold from accumulating in the local area of ​​the pipeline during the flow of liquid nitrogen, thereby reducing the risk of frosting. The Z-shaped structure ensures the stability of the liquid nitrogen flow and avoids flow velocity fluctuations and pressure changes that may be caused by sharp turns.

[0024] The delivery pipeline 6 is L-shaped, and the L-shaped design helps to further stabilize the flow of liquid nitrogen, while forming a reasonable match with the Z-shaped design of the liquid nitrogen pipeline 3. The L-shaped design can reduce the pressure drop in the pipeline and maintain the stability and efficiency of the liquid nitrogen flow. The L-shaped pipeline layout can make better use of space, especially in the case of compact equipment layout, to avoid unnecessary space waste.

[0025] The liquid nitrogen pipeline 3 is connected to the delivery pipeline 6 through the extraction pump 4 and is U-shaped as a whole. The U-shaped design can effectively close the low-temperature area and prevent the cold from leaking into the external environment, thereby reducing the possibility of frosting. The U-shaped structure can form a better pressure balance in the system and avoid unnecessary pressure fluctuations during the flow of liquid nitrogen.

[0026] A fixing plate 8 is provided at the connection between the liquid nitrogen pipeline 3 and the cold box 1. The fixing plate 8 can firmly fix the liquid nitrogen pipeline 3 between the cold box 1 and the outside to prevent the pipeline from being displaced or damaged due to thermal expansion and contraction in a low-temperature environment. By fixing the fixing plate 8, the tightness of the pipeline connection is enhanced.

[0027] The liquid nitrogen pipeline 3 has a diameter of 15 mm and a wall thickness of 2.11 mm, and is made of aluminum alloy. The 15 mm diameter design can meet the demand for liquid nitrogen flow, ensuring both the flow rate and avoiding excessive flow rate. The wall thickness ensures the mechanical strength of the pipeline in a low temperature environment and will not be damaged due to low temperature embrittlement. The aluminum alloy material has good corrosion resistance and low temperature toughness, is suitable for use in a liquid nitrogen environment, and can maintain stability for a long time.

[0028] The horizontal length of the liquid nitrogen pipeline 3 is 1000 mm. The horizontal length design of 1000 mm not only ensures the stability of liquid nitrogen flow, but also takes into account the convenience of installation and maintenance, and is suitable for the layout requirements between most cold boxes 1 and storage tanks 7, avoiding installation problems caused by being too long or too short.

[0029] The liquid nitrogen pipeline 3 is provided with a liquid nitrogen valve 5, which can accurately adjust the liquid nitrogen flow rate to ensure the operational flexibility and stability of the system under different working conditions, increase safety, and be able to quickly cut off the liquid nitrogen supply in an emergency to prevent accidents.

[0030] Calculation method: liquid nitrogen temperature is t = -196 ° C, ambient temperature is t0 = 20 ° C, pipe diameter is DN = 15 mm, wall thickness is 2.11 mm, thermal conductivity is aluminum alloy material, the average value in the temperature range is λ = 12.2 W / (m·K). As the outside temperature decreases, the height of the liquid column will increase, because the decrease in outside temperature causes the speed of heat conduction through the pipe wall to decrease, and the curvature of the pipe temperature change decreases, so the height of the gas-liquid equilibrium point increases.

[0031] The standard parts used in the utility model can all be purchased from the market, special-shaped parts can be customized according to the description in the specification and the drawings, the specific connection methods of each part adopt the conventional means such as mature bolts, rivets, welding, etc. in the prior art, the machinery, parts and equipment all adopt the conventional models in the prior art, and the circuit connection adopts the conventional connection method in the prior art, which will not be described in detail here. The content not described in detail in this specification belongs to the prior art known to professional and technical personnel in this field.

[0032] The above description is only a preferred embodiment of the present invention and does not limit the present invention in other forms. Any technician familiar with the profession may use the technical content disclosed above to change or modify it into an equivalent embodiment with equivalent changes and apply it to other fields. However, any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention without departing from the content of the technical solution of the present invention still falls within the protection scope of the technical solution of the present invention.

Claims

1. Liquid nitrogen extraction U-bend pipeline, including a cold box, characterized in that: A distillation tower is arranged inside the cold box, a liquid nitrogen pipeline is led out from the top of the distillation tower, the liquid nitrogen pipeline extends to the outside of the cold box, the liquid nitrogen pipeline is connected to an extraction pump, the rear side of the extraction pump is connected to a delivery pipeline connected to a storage tank, the liquid nitrogen pipeline is Z-shaped, the delivery pipeline is L-shaped, and the liquid nitrogen pipeline is connected to the delivery pipeline through the extraction pump to form a U-shape as a whole.

2. The liquid nitrogen extraction U-bend pipeline according to claim 1, characterized in that: A fixing plate is provided at the connection between the liquid nitrogen pipeline and the cold box.

3. The liquid nitrogen extraction U-bend pipeline according to claim 1, characterized in that: The liquid nitrogen pipeline has a diameter of 15 mm and a wall thickness of 2.11 mm and is made of aluminum alloy.

4. The U-bend pipeline for extracting liquid nitrogen according to claim 3, characterized in that: The transverse length of the liquid nitrogen pipeline is 1000 mm.

5. The U-bend pipeline for extracting liquid nitrogen according to claim 1, characterized in that: The liquid nitrogen pipeline is provided with a liquid nitrogen valve.

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