Pre-cooling device for liquefied natural gas pipeline

Abstract

The utility model relates to the technical field of low-temperature medium ship unloading pipeline precooling, in particular to a liquefied natural gas pipeline precooling device which comprises a precooling device body, a check valve is arranged on a liquid nitrogen input pipe, guide plates are arranged on the upper portion and the lower portion of the inner side of the precooling device body respectively, and a liquid nitrogen input cavity is formed in the precooling device body and located at the bottoms of the guide plates. The utility model relates to a pre-cooling device which is particularly used in a natural gas pipeline, the contact area of liquid nitrogen and circulating nitrogen is increased through a round hole and a spiral piece, the liquid nitrogen and the circulating nitrogen in the pre-cooling device are fully mixed and gasified into low-temperature nitrogen, pre-cooling of a ship unloading pipeline is achieved, cold energy of the low-temperature liquid nitrogen is fully utilized, and the ship unloading efficiency is improved. The precooled nitrogen is recycled again, nitrogen emission in the precooling process of the propane unshipping pipeline is reduced, meanwhile, cold energy of low-temperature liquid nitrogen is fully utilized, the using amount of the liquid nitrogen in the precooling process is greatly reduced, and practicability is good.

Description

Technical Field

[0001] The utility model relates to the technical field of precooling of low-temperature medium ship unloading pipelines, in particular to a liquefied natural gas pipeline precooling device. Background Art

[0002] When using propane dehydrogenation technology to prepare propylene, a large amount of propane is required as a raw material. In order to facilitate transportation and storage, the propane gas is liquefied at low temperature and then transported to the dock by a propane tanker. It enters the low-temperature propane storage tank for storage through the propane unloading pipeline. Before the low-temperature propane storage tank receives the low-temperature propane shipped by ship for the first time, in order to avoid damage to the propane unloading pipeline due to too rapid temperature changes or too large temperature difference between the top and bottom of the pipeline, a low-temperature medium is required to pre-cool the propane unloading pipeline. The low-temperature propane unloading operation can only be started after the pre-cooling temperature is close to the temperature of the shipped low-temperature propane.

[0003] A Chinese patent discloses a pipeline precooling device capable of controlling temperature (authorization announcement number CN 213420292U). The patented technology can not only control the flow rate and temperature during the precooling process, but also monitor the precooling temperature in real time, which greatly improves the pipeline precooling efficiency. However, the natural gas pipeline precooling device heats and vaporizes the low-temperature liquid nitrogen using an air vaporizer, and then uses the vaporized low-temperature nitrogen to precool the low-temperature natural gas pipeline. The nitrogen is directly discharged into the atmosphere after precooling. The nitrogen emission during the precooling process of the propane unloading pipeline is large, and the cold energy of the low-temperature liquid nitrogen is not utilized, which increases the amount of liquid nitrogen used during the precooling process. Moreover, the gas is still blown from top to bottom, so that the gas first contacts the upper end of the pipeline and precools it, while the lower end of the pipeline can only be precooled after the gas settles to the lower end of the box, resulting in the inability to precool the upper and lower ends of the pipeline at the same time during the precooling process, causing uneven precooling of the pipeline and deformation or even cracking, which greatly increases the production cost of the pipeline.

[0004] Therefore, those skilled in the art provide a liquefied natural gas pipeline precooling device to solve the problems raised in the above background technology. Utility Model Content

[0005] In order to solve the above technical problems, the utility model provides a liquefied natural gas pipeline precooling device, including a precooling device, a check valve is arranged on the liquid nitrogen input pipe, guide plates are arranged on the upper and lower parts of the inner side of the precooling device, a liquid nitrogen input cavity is arranged at the bottom of the guide plate inside the precooling device, a circular hole is opened on the liquid nitrogen input cavity, a connecting frame is arranged inside the precooling device, a connecting shaft is fixed at the bottom of the connecting frame, a support rod is arranged on the connecting shaft, and spiral sheets are arranged at the upper and lower ends of the support rod.

[0006] Preferably: Pipe 1 is arranged on the left side of the precooling device, and flange 1 is arranged on the left side of pipe 1. Pipe 2 is connected to the right side of the cooling device, and flange 2 is arranged on the right end of pipe 2. Flange 1 and flange 2 facilitate the connection of pipe 1 and pipe, and a sealing cover plate is arranged at the front of the precooling device. Fixing bolts are arranged at the four corners of the sealing cover plate, and the number of fixing bolts is four, and the sealing cover plate is fastened and connected by the four fixing bolts.

[0007] Preferably: the top and left side of the precooling device are both provided with a liquid nitrogen input pipe, and a limit block is provided on the liquid nitrogen input pipe. The check valve facilitates the non-return setting of the liquid nitrogen input pipe, and the guide plate is arranged at an angle inside the precooling device. The number of guide plates is several and is arranged as required. The number of circular holes is six, arranged in threes. Support blocks are provided at the four corners of the lower end of the precooling device, and an anti-skid pad is provided at the lower end of the support block. The number of the support blocks and the anti-skid pad is four, and they are arranged symmetrically with each other.

[0008] Technical effects and advantages of the utility model:

[0009] 1. The utility model relates to a precooling device, which is specifically used in a natural gas pipeline. The contact area between liquid nitrogen and circulating nitrogen is increased by the circular holes and spiral sheets provided, so that the liquid nitrogen and the circulating nitrogen inside the precooling device are fully mixed and gasified into low-temperature nitrogen, thereby realizing the precooling of the ship unloading pipeline, making full use of the cold energy of the low-temperature liquid nitrogen, and recycling the nitrogen after precooling, thereby reducing the nitrogen emission in the precooling process of the propane ship unloading pipeline, and making full use of the cold energy of the low-temperature liquid nitrogen, greatly reducing the use of liquid nitrogen in the precooling process, and having good practicality.

[0010] 2. By setting the inclined guide plate, liquid nitrogen delivery tube cavity and circular hole, each surface of the pipeline can be directly connected with the gas, which can not only improve the pre-cooling efficiency of the pipeline, but also improve the more uniform contact pre-cooling of the raw material and the gas when the gas pre-cools the raw material. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a schematic diagram of a liquefied natural gas pipeline precooling device provided in an embodiment of the present application. Figure 1 ;

[0012] Figure 2 This is a schematic diagram of a liquefied natural gas pipeline precooling device provided in an embodiment of the present application. Figure 2 ;

[0013] Figure 3 It is a schematic structural diagram of a top view of a liquefied natural gas pipeline precooling device provided in an embodiment of the present application;

[0014] Figure 4It is a structural schematic diagram of a connecting frame, a connecting shaft, a spiral support rod and a spiral in a liquefied natural gas pipeline precooling device provided in an embodiment of the present application;

[0015] Figure 5 It is a structural schematic diagram of a right view of a liquefied natural gas pipeline precooling device provided in an embodiment of the present application;

[0016] Figure 6 It is a structural schematic diagram of a liquid nitrogen delivery lumen and a circular hole in a liquefied natural gas pipeline precooling device provided in an embodiment of the present application;

[0017] Figure 7 This is a liquefied natural gas pipeline precooling device provided in the embodiment of the present application Figure 2 Schematic diagram of the structure at A in the middle.

[0018] In the figure: 1. precooling device; 2. pipeline 1; 3. flange 1; 4. pipeline 2; 5. flange 2; 6. sealing cover plate; 7. fixing bolt; 8. liquid nitrogen input pipe; 9. limit block; 10. check valve; 11. guide plate; 12. liquid nitrogen delivery tube cavity; 13. round hole; 14. connecting frame; 15. connecting shaft; 16. support rod; 17. spiral sheet; 18. support block; 19. anti-slip pad. DETAILED DESCRIPTION

[0019] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. The embodiments of the present invention are provided for the purpose of illustration and description, and are not intended to be exhaustive or to limit the present invention to the disclosed forms. Many modifications and variations are obvious to those of ordinary skill in the art. The embodiments are selected and described in order to better illustrate the principles and practical applications of the present invention, and to enable those of ordinary skill in the art to understand the present invention and thereby design various embodiments with various modifications suitable for specific purposes. Example 1

[0020] See also Figures 1 to 7In this embodiment, a liquefied natural gas pipeline precooling device is provided, including a precooling device 1, a pipeline 2 is arranged on the left side of the precooling device 1, a flange 3 is arranged on the left side of the pipeline 2, a pipeline 4 is connected to the right side of the precooling device 1, a flange 25 is arranged on the right end of the pipeline 24, and the flange 13 and the flange 25 facilitate the connection between the pipeline 2 and the pipeline. A sealing cover plate 6 is arranged at the front of the precooling device 1, and fixing bolts 7 are arranged at the four corners of the sealing cover plate 6. The number of the fixing bolts 7 is four, and the sealing cover plate 6 is fastened and connected by the four fixing bolts 7. The top and left side of the precooling device 1 are both provided with a liquid nitrogen input pipe 8. A limit block 9 is provided on the liquid nitrogen input pipe 8, and the precooling device 1 is limited by the limit block 9. A check valve 10 is provided on the liquid nitrogen input pipe 8, and the check valve 10 facilitates the non-return setting of the liquid nitrogen input pipe 8. Guide plates 11 are provided on the upper and lower parts of the inner side of the precooling device 1. The guide plate 11 is inclined inside the precooling device 1. The number of guide plates 11 is several and is set as required. A liquid nitrogen input cavity is provided at the bottom of the guide plate 11 inside the precooling device 1. A circular hole 13 is opened on the liquid nitrogen input cavity. The number of circular holes 13 is six and is set in threes. A connecting frame 14 is provided inside the precooling device 1. The connecting frame 14 A connecting shaft 15 is fixed to the bottom of the precooling device 1, and a support rod 16 is arranged on the connecting shaft 15. The upper and lower ends of the support rod 16 are provided with spiral pieces 17. Support blocks 18 are arranged at the four corners of the lower end of the precooling device 1, and anti-skid pads 19 are arranged at the lower ends of the support blocks 18. The number of the support blocks 18 and the anti-skid pads 19 is four, and they are arranged symmetrically with each other. When in use, the precooling device 1 is first placed to the position where the natural gas pipeline needs to be precooled by the support blocks 18 and the anti-skid pads 19. When in use, the support blocks 18 and the anti-skid pads 19 play a role of stable support for pipelines 1 2 and 2 4, and the equipment is connected to the natural gas pipeline through flanges 1 3 and 2 5. The pipeline is connected, and then the two liquid nitrogen input pipes 8 are connected to the external temporary liquid nitrogen supply equipment. After the liquid nitrogen enters the annular liquid nitrogen delivery pipe cavity 12, it is evenly sprayed into the interior of the precooling device 1 through the circular hole 13 and the inclined guide plate 11. The circular hole 13 and the spiral sheet 17 increase the contact area between the liquid nitrogen and the circulating nitrogen, so that the liquid nitrogen and the circulating nitrogen inside the precooling device 1 are fully mixed and gasified into low-temperature nitrogen, so as to realize the precooling of the unloading pipeline, make full use of the cold energy of the low-temperature liquid nitrogen, and recycle the nitrogen after precooling, thereby reducing the nitrogen emission in the precooling process of the propane unloading pipeline, and at the same time make full use of the cold energy of the low-temperature liquid nitrogen, greatly reduce the use of liquid nitrogen in the precooling process, and have good practicality.

[0021] Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field and related fields without creative work should fall within the scope of protection of the present invention. Structures, devices and operating methods not specifically described and explained in the present invention shall be implemented according to conventional means in the field unless otherwise specified and limited.

Claims

1. A liquefied natural gas pipeline precooling device, comprising a precooling device (1), characterized in that: A check valve (10) is provided on the liquid nitrogen input pipe (8), guide plates (11) are provided on both the upper and lower parts of the inner side of the precooling device (1), a liquid nitrogen input chamber is provided at the bottom of the guide plate (11) inside the precooling device (1), a circular hole (13) is provided on the liquid nitrogen input chamber, a connecting frame (14) is provided inside the precooling device (1), a connecting shaft (15) is fixed at the bottom of the connecting frame (14), a support rod (16) is provided on the connecting shaft (15), and spiral plates (17) are provided at the upper and lower ends of the support rod (16).

2. A liquefied natural gas pipeline precooling device according to claim 1, characterized in that: A pipe (2) is arranged on the left side of the precooling device (1), and a flange (3) is arranged on the left side of the pipe (2).

3. A liquefied natural gas pipeline precooling device according to claim 2, characterized in that: The right side of the precooling device (1) is connected to a second pipe (4), and a second flange (5) is provided at the right end of the second pipe (4).

4. A liquefied natural gas pipeline precooling device according to claim 3, characterized in that: The flange one (3) and the flange two (5) facilitate the connection between the pipeline one (2) and the pipeline, and a sealing cover plate (6) is provided at the front of the precooling device (1).

5. A liquefied natural gas pipeline precooling device according to claim 4, characterized in that: The four corners of the sealing cover plate (6) are each provided with fixing bolts (7), and the number of the fixing bolts (7) is four.

6. A liquefied natural gas pipeline precooling device according to claim 1, characterized in that: The top and left side of the precooling device (1) are both provided with a liquid nitrogen input pipe (8), and a limit block (9) is provided on the liquid nitrogen input pipe (8).

7. A liquefied natural gas pipeline precooling device according to claim 1, characterized in that: The check valve (10) facilitates the non-return setting of the liquid nitrogen input pipe (8); the guide plate (11) is arranged at an angle inside the pre-cooling device (1); and the number of guide plates (11) is several and is arranged according to needs.

8. The liquefied natural gas pipeline precooling device according to claim 1, characterized in that: The number of the circular holes (13) is six, which are arranged in a three-by-three arrangement.

9. A liquefied natural gas pipeline precooling device according to claim 1, characterized in that: Support blocks (18) are provided at the four corners of the lower end of the precooling device (1), and anti-skid pads (19) are provided at the lower ends of the support blocks (18). The number of the support blocks (18) and the anti-skid pads (19) provided is four each, and they are symmetrically arranged.

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