Liquid ammonia loading device capable of emptying liquid ammonia

Abstract

The utility model discloses a liquid ammonia loading device capable of emptying liquid ammonia, and belongs to the technical field of ammonia synthesis. Comprising a liquid ammonia spherical tank, a liquid ammonia header pipe, N liquid ammonia branch pipes, N liquid ammonia unloading crane pipes, a nitrogen inlet pipe, a medium-pressure nitrogen storage tank, a nitrogen header pipe and N nitrogen branch pipes, and each liquid ammonia branch pipe is provided with a second flow control structure and a second control valve; the medium-pressure nitrogen storage tank is connected with a medium-pressure nitrogen pipe network through a nitrogen inlet pipe, and a first pressure transmitter is arranged on the medium-pressure nitrogen storage tank and connected with a nitrogen header pipe. The nitrogen main pipe is respectively connected with the N liquid ammonia branch pipes through N nitrogen branch pipes; the nitrogen inlet pipe is provided with a third control valve, a pressure control valve and a first check valve, the pressure control valve is interlocked with the first pressure transmitter, the nitrogen header pipe is provided with an emptying pipeline, a second pressure transmitter and a fourth control valve, the emptying pipeline is provided with a third safety relief valve, and the third control valve is interlocked with the second pressure transmitter; and a fifth control valve, a second check valve and a first pressure gauge are arranged on the nitrogen branch pipe.

Description

Technical Field

[0001] This utility model belongs to the field of synthetic ammonia technology, and specifically relates to a liquid ammonia loading device that can completely drain liquid ammonia. Background Technology

[0002] Liquid ammonia is a toxic and flammable medium with a high saturated vapor pressure, reaching 1.26 MPa at 30°C. Therefore, its storage and transportation require ammonia tank trucks. The loading of liquid ammonia for synthetic ammonia is typically done using a loading arm pressurized for loading. The process is as follows: liquid ammonia is transferred from a liquid ammonia spherical tank to a liquid ammonia tank truck using low-pressure nitrogen (the pressure needs to be controlled to create a pressure differential, ensuring the pressure of the liquid ammonia is 0.15-0.3 MPa higher than the pressure inside the ammonia tank truck). The gaseous phase in the liquid ammonia tank truck is then returned to the liquid ammonia spherical tank.

[0003] For example, patent application number CN202221431275.7 discloses a pressure conveying device for unloading and conveying liquid ammonia, including a liquid ammonia unloading arm, a liquid ammonia spherical tank, and a liquid ammonia external delivery pipe; the liquid ammonia unloading arm is connected in parallel with a gas phase unloading arm pipeline and a liquid phase unloading arm pipeline. The liquid ammonia unloading arm is connected to the liquid ammonia spherical tank via a liquid inlet pipe. An internal pressure gauge is installed on the liquid ammonia spherical tank. The liquid ammonia spherical tank is connected to a liquid ammonia delivery pipe, which extends downstream for delivery. A nitrogen delivery pipe is introduced, and a nitrogen pressure regulating valve is installed on this pipe. An upstream pressure gauge is installed on the nitrogen delivery pipe upstream of the regulating valve, and a downstream pressure gauge is installed on the nitrogen delivery pipe downstream of the regulating valve. A node valve is installed on the nitrogen delivery pipe downstream of the downstream pressure gauge. The nitrogen delivery pipe downstream of the node valve splits into two paths: one is the loading arm inlet pipe, and the other is the spherical tank inlet pipe. An loading arm inlet valve is installed on the loading arm inlet pipe, and its end connects to the liquid ammonia unloading arm. A spherical tank inlet valve is installed on the spherical tank inlet pipe, and its end connects to the liquid ammonia spherical tank.

[0004] When the liquid ammonia tanker reaches the set filling volume, the liquid ammonia shut-off valve automatically closes. At this time, it is necessary to close the loading valve of the liquid ammonia tanker and remove the loading arm. When the liquid ammonia unloading loading arm is removed, there is a small amount of residual liquid ammonia in the loading arm. The residual liquid ammonia may vaporize and leak, causing frequent alarms at the loading site (ammonia leak alarm). Furthermore, the leak may pose a safety risk of burns and frostbite to loading and unloading personnel. Utility Model Content

[0005] To address the aforementioned problems, this utility model provides a liquid ammonia loading device capable of completely draining liquid ammonia. It uses nitrogen gas (at a specific pressure) to purge residual liquid ammonia from the unloading arm into the ammonia truck's tank, ensuring no residual liquid ammonia leaks when the unloading arm is removed. The technical solution is as follows:

[0006] This utility model provides a liquid ammonia loading device capable of completely draining liquid ammonia, comprising a liquid ammonia spherical tank, a main liquid ammonia pipe 1 output from the spherical tank, N liquid ammonia branch pipes 2 output from the main liquid ammonia pipe 1, and liquid ammonia unloading arms 3 at the ends of the branch pipes 2. The main liquid ammonia pipe 1 is sequentially equipped with a first flow control structure 11, a first safety relief valve 12, a liquid ammonia return branch pipe 13, a first control valve 14, a low-pressure nitrogen branch pipe 15, and a second safety relief valve 16 along the fluid transport direction. The branch pipes 2 are sequentially equipped with a second flow control structure 21 and a second control valve 22 along the fluid transport direction. The low-pressure nitrogen branch pipe 15 is connected to a low-pressure nitrogen pipeline network. The device also includes a nitrogen inlet pipe 4, a medium-pressure nitrogen storage tank 5, a nitrogen main pipe 6, and N nitrogen branch pipes 7. The medium-pressure nitrogen storage tank 5 is connected to the medium-pressure nitrogen pipeline network via the nitrogen inlet pipe 4 and is equipped with a first pressure transmitter 56. The exhaust port 55 is connected to the nitrogen main pipe 6; the nitrogen main pipe 6 is connected to N liquid ammonia branch pipes 2 via N nitrogen branch pipes 7; the nitrogen inlet pipe 4 is sequentially equipped with a third control valve 41, a pressure control valve 42 and a first check valve 43, the pressure control valve 42 is interlocked with the first pressure transmitter 56; the nitrogen main pipe 6 is sequentially equipped with an vent line 61, a second pressure transmitter 62 and a fourth control valve 63 along the gas delivery direction; the vent line 61 is equipped with a third safety relief valve 64, the third control valve 41 is interlocked with the second pressure transmitter 62; the nitrogen branch pipes 7 are equipped with a fifth control valve 71, a second check valve 72 and a first pressure gauge 73, and their ends are connected to the liquid ammonia branch pipe 2 between the second flow control structure 21 and the second control valve 22; the pressure relief pressure of the third safety relief valve 64 is less than the pressure relief pressure of the second safety relief valve 16.

[0007] Specifically, in this embodiment of the present invention, the pressure relief of the first safety relief valve 12, the second safety relief valve 16, and the third safety relief valve 64 are 3.1 MPa, 2.16 MPa, and 1.9 MPa, respectively.

[0008] Furthermore, in this embodiment of the invention, the low-pressure nitrogen pipeline 15 is provided with a third check valve 17, a sixth control valve 18, and a second pressure gauge 19.

[0009] Specifically, in this embodiment of the present invention, the third check valve 17, the sixth control valve 18, and the second pressure gauge 19 are arranged sequentially along the gas conveying direction, and the fifth control valve 71, the second check valve 72, and the first pressure gauge 73 are arranged sequentially along the gas conveying direction.

[0010] In this embodiment of the utility model, the medium-pressure nitrogen storage tank 5 is a vertical tank structure with multiple support legs 51 at the bottom, an air vent 52 at the bottom, an air inlet 53 and an installation interface 54 at the bottom, an exhaust port 55 at the top, and a manhole 57 in the middle. The multiple support legs 51 are evenly distributed around the medium-pressure nitrogen storage tank 5. The nitrogen inlet pipe 4 is connected to the air inlet 53, and the first pressure transmitter 56 is mounted on the installation interface 54.

[0011] Specifically, the medium-pressure nitrogen storage tank 5 in this embodiment of the present invention has a specification of Φ1300mm*1800mm.

[0012] Specifically, in this embodiment of the present invention, the nitrogen inlet pipe 4, the nitrogen main pipe 6, and the vent pipe 61 are all DN50, and the nitrogen branch pipes 7 are all DN20.

[0013] In this embodiment of the present invention, the third control valve 41 and the pressure control valve 42 are both pneumatic valves, and the fourth control valve 63 and the fifth control valve 71 are both ball valves.

[0014] The beneficial effects of the technical solution provided by this utility model embodiment are as follows: This utility model embodiment provides a liquid ammonia loading device that can completely drain liquid ammonia. It uses nitrogen (the synthetic ammonia system has a medium-pressure nitrogen pipeline network, which is an existing structure and needs to be depressurized to a specific pressure) to blow residual liquid ammonia from the unloading arm into the ammonia truck tank. This ensures that there is no residual liquid ammonia leakage when dismantling the unloading arm, and eliminates the safety risk of burns and frostbite to workers. Simultaneously, multiple methods are used to ensure stable nitrogen pressure, guaranteeing the purging of residual liquid ammonia while avoiding affecting the pressure inside the ammonia truck tank. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the liquid ammonia loading device that can completely drain liquid ammonia in an embodiment of this utility model;

[0016] Figure 2 This is a schematic diagram of the structure of a medium-pressure nitrogen storage tank.

[0017] In the diagram: 1. Liquid ammonia main pipe, 2. Liquid ammonia branch pipe, 3. Liquid ammonia unloading arm, 4. Nitrogen inlet pipe, 5. Medium-pressure nitrogen storage tank, 6. Nitrogen main pipe, 7. Nitrogen branch pipe;

[0018] 11 First flow control structure, 12 First safety relief valve, 13 Liquid ammonia reflux branch pipe, 14 First control valve, 15 Low-pressure nitrogen branch pipe, 16 Second safety relief valve, 17 Third check valve, 18 Sixth control valve, 19 Second pressure gauge;

[0019] 21 Second flow control structure; 22 Second control valve;

[0020] 41 Third control valve, 42 Pressure control valve, 43 First check valve;

[0021] 51 Outrigger, 52 Exhaust port, 53 Air inlet, 54 Mounting interface, 55 Exhaust port, 56 First pressure transmitter, 57 Manhole;

[0022] 61 Drainage pipeline, 62 Second pressure transmitter, 63 Fourth control valve;

[0023] 71 Fifth control valve, 72 Second check valve, 73 First pressure gauge. Detailed Implementation

[0024] To make the objectives, technical solutions and advantages of this utility model clearer, the utility model will be described in further detail below with reference to the accompanying drawings.

[0025] Example 1

[0026] See Figure 1-2Example 1 provides a liquid ammonia loading device capable of completely draining liquid ammonia. This device includes a liquid ammonia spherical tank, a liquid ammonia main pipe 1, a nitrogen inlet pipe 4, a medium-pressure nitrogen storage tank 5, a nitrogen main pipe 6, N liquid ammonia branch pipes 2, N liquid ammonia unloading arms 3 (including gas phase unloading arm pipelines and liquid phase unloading arm pipelines), and N nitrogen branch pipes 7. The beginning of the liquid ammonia main pipe 1 is connected to the liquid ammonia spherical tank. Along the fluid transport direction, it is sequentially equipped with a first flow control structure 11, a first safety relief valve 12, a liquid ammonia return branch pipe 13 (the end of which is connected to a specific container and equipped with a valve), a first control valve 14 (interlocked with the valve on the gas phase unloading arm pipeline), a low-pressure nitrogen branch pipe 15, and a second safety relief valve 16, etc., and outputs N liquid ammonia branch pipes 2 at its end. The N liquid ammonia branch pipes 2, the N liquid ammonia unloading arms 3, and the N nitrogen branch pipes 7 are arranged in a one-to-one correspondence. N is an integer from 2 to 10, typically 3 to 5. Each liquid ammonia branch pipe 2 has a liquid ammonia unloading arm 3 at its end. Along the fluid transport direction, the liquid ammonia branch pipe 2 is equipped with a second flow control structure 21 and a second control valve 22, etc. The low-pressure nitrogen branch pipe 15 is connected to the low-pressure nitrogen pipeline network and is equipped with a third check valve 17, a sixth control valve 18, and a second pressure gauge 19, etc., along the gas transport direction. The medium-pressure nitrogen storage tank 5 is connected to the medium-pressure nitrogen pipeline network (nitrogen pressure approximately 6.4 MPa) via a nitrogen inlet pipe 4, and is equipped with a first pressure transmitter 56. Its exhaust port 55 is connected to the nitrogen main pipe 6. The nitrogen main pipe 6 is connected to N liquid ammonia branch pipes 2 via N nitrogen branch pipes 7. The nitrogen inlet pipe 4 is equipped with a third control valve 41, a pressure control valve 42, and a first check valve 43, etc., and the pressure control valve 42 is interlocked with the first pressure transmitter 56. Along the gas delivery direction, the nitrogen main pipe 6 is equipped with a vent line 61, a second pressure transmitter 62, and a fourth control valve 63. The vent line 61 is equipped with a third safety relief valve 64, and the third control valve 64 is interlocked with the second pressure transmitter 62. Along the gas delivery direction, the nitrogen branch pipe 7 is equipped with a fifth control valve 71, a second check valve 72, and a first pressure gauge 73, and its end is connected to the liquid ammonia branch pipe 2 between the second flow control structure 21 and the second control valve 22. The pressure relief of the third safety relief valve 64 is less than the pressure relief of the second safety relief valve 16. During loading, the fifth control valve 71 is closed, and the valve on the liquid ammonia branch pipe 2 is open. When removing the liquid ammonia unloading arm 3 (during purging residual liquid ammonia), the second flow control structure 21 is closed, and the valve on the nitrogen branch pipe 7 is open.

[0027] In this embodiment of the invention, the third control valve 41 and the pressure control valve 42 are both pneumatic valves, and the fourth control valve 63 and the fifth control valve 71 are both ball valves. The first flow control structure 11 and the second flow control structure 21 both include a flow meter and a flow control valve, and the flow meter and the flow control valve are interlocked.

[0028] Example 2

[0029] Example 2 provides a liquid ammonia loading device that can drain liquid ammonia. Its structure is basically the same as that of Example 1, except that the pressure relief pressures of the first safety relief valve 12, the second safety relief valve 16 and the third safety relief valve 64 in this example are 3.1 MPa, 2.16 MPa and 1.9 MPa, respectively.

[0030] Example 3

[0031] See Figure 2 Example 3 provides a liquid ammonia loading device capable of completely draining liquid ammonia. Its structure is basically the same as that of Example 1, except that the medium-pressure nitrogen storage tank 5 in this embodiment is a vertical tank structure. It has multiple (specifically four) support legs 51 at its lower part, a vent 52 (with a valve) at its bottom, an air inlet 53 and a mounting interface 54 at its lower part, an exhaust port 55 at its top, and a manhole 57 in its middle. The multiple support legs 51 are evenly distributed around the medium-pressure nitrogen storage tank 5. The end of the nitrogen inlet pipe 4 is connected to the air inlet 53, and the first pressure transmitter 56 is mounted on the mounting interface 54. The air inlet 53 and the mounting interface 54 are positioned opposite each other.

[0032] Specifically, the medium-pressure nitrogen storage tank 5 in this embodiment of the present invention has the following specifications: Φ1300mm*1800mm, design pressure of 1.9MPa, working pressure of 1.7MPa, design temperature of -19℃ / 60℃, working temperature of room temperature, corrosion allowance of 3mm, weld joint coefficient of 1.0, and volume of 2.9m³. 3 The specifications of the air inlet 53 and the exhaust port 55 are DN50, the specification of the vent port 52 is DN20, the specification of the mounting interface 54 is DN15, and the specification of the manhole 57 is DN500.

[0033] Example 4

[0034] Example 4 provides a liquid ammonia loading device capable of completely draining liquid ammonia. Its structure is basically the same as that of Example 3, except that: in this embodiment, the nitrogen inlet pipe 4, nitrogen main pipe 6, and vent pipe 61 are all DN50, and the nitrogen branch pipe 7 is DN20; correspondingly, the instruments are set accordingly. The upstream design pressure of the pressure control valve 42 is 6.6 MPa, and the downstream design pressure is 1.6 MPa. The design pressure of the first pressure transmitter 56 is 1.9 MPa, and the operating pressure is 1.6 MPa. The design pressure of the second pressure transmitter 6 is 2.16 MPa, and the operating pressure is 1.6 MPa. The design pressure of the first pressure gauge 73 is 2.16 MPa, and the operating pressure is 1.6 MPa.

[0035] In this patent, the terms "first", "second", "third", "fourth", "fifth" and "sixth" serve only to distinguish the parts and have no other special meaning.

[0036] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A liquid ammonia loading device capable of completely emptying liquid ammonia, comprising a liquid ammonia spherical tank, a liquid ammonia main pipe (1) output by the liquid ammonia spherical tank, N liquid ammonia branch pipes (2) output by the liquid ammonia main pipe (1), and liquid ammonia unloading loading arms (3) at the ends of the liquid ammonia branch pipes (2), wherein the liquid ammonia main pipe (1) is sequentially provided with a first flow control structure (11), a first safety relief valve (12), a liquid ammonia return branch pipe (13), a first control valve (14), a low-pressure nitrogen gas branch pipe (15), and a second safety relief valve (16) in the fluid conveying direction, the liquid ammonia branch pipe (2) is sequentially provided with a second flow control structure (21) and a second control valve (22) in the fluid conveying direction, and the low-pressure nitrogen gas branch pipe (15) is connected with a low-pressure nitrogen gas pipe network. The device further comprises a nitrogen gas inlet pipe (4), a medium-pressure nitrogen gas storage tank (5), a nitrogen gas main pipe (6), and N nitrogen gas branch pipes (7), wherein the medium-pressure nitrogen gas storage tank (5) is connected with a medium-pressure nitrogen gas pipe network through the nitrogen gas inlet pipe (4), is provided with a first pressure transmitter (56) thereon, and has an exhaust port (55) connected with the nitrogen gas main pipe (6); the nitrogen gas main pipe (6) is connected with the N liquid ammonia branch pipes (2) through the N nitrogen gas branch pipes (7) respectively; the nitrogen gas inlet pipe (4) is sequentially provided with a third control valve (41), a pressure control valve (42), and a first check valve (43), the pressure control valve (42) is interlocked with the first pressure transmitter (56), the nitrogen gas main pipe (6) is sequentially provided with an emptying pipeline (61), a second pressure transmitter (62), and a fourth control valve (63) in the gas conveying direction, the emptying pipeline (61) is provided with a third safety relief valve (64), and the third control valve (41) is interlocked with the second pressure transmitter (62); the nitrogen gas branch pipe (7) is provided with a fifth control valve (71), a second check valve (72), and a first pressure gauge (73), and the end of the nitrogen gas branch pipe (7) is connected with the liquid ammonia branch pipe (2) between the second flow control structure (21) and the second control valve (22), and the relief pressure of the third safety relief valve (64) is less than the relief pressure of the second safety relief valve (16).

2. The netable liquid ammonia liquid ammonia loading device according to claim 1, characterized in that, The relief pressures of the first safety relief valve (12), the second safety relief valve (16), and the third safety relief valve (64) are 3.1 Mpa, 2.16 Mpa, and 1.9 Mpa respectively.

3. The netable liquid ammonia liquid ammonia loading device according to claim 1, characterized in that, The low-pressure nitrogen gas pipeline (15) is provided with a third check valve (17), a sixth control valve (18), and a second pressure gauge (19).

4. The netable liquid ammonia liquid ammonia loading device according to claim 3, characterized in that, The third check valve (17), the sixth control valve (18), and the second pressure gauge (19) are sequentially arranged in the gas conveying direction, and the fifth control valve (71), the second check valve (72), and the first pressure gauge (73) are sequentially arranged in the gas conveying direction.

5. The netable liquid ammonia liquid ammonia loading device according to claim 1, characterized in that, The medium-pressure nitrogen storage tank (5) is a vertical tank structure, which is provided with multiple supporting legs (51) at the lower part, a bottom emptying port (52), an air inlet (53) and a mounting interface (54) at the lower part, an air outlet (55) at the top, a manhole (57) in the middle; the multiple supporting legs (51) are uniformly distributed around the medium-pressure nitrogen storage tank (5), the nitrogen air inlet pipe (4) is connected with the air inlet (53), and the first pressure transmitter (56) is arranged on the mounting interface (54).

6. The netable liquid ammonia liquid ammonia loading device according to claim 1, characterized in that, The specification of the medium-pressure nitrogen storage tank (5) is Φ1300mm*1800mm.

7. The netable liquid ammonia liquid ammonia loading device according to claim 1, characterized in that, The specifications of the nitrogen air inlet pipe (4), the nitrogen main pipe (6) and the emptying pipeline (61) are all DN50, and the specifications of the nitrogen branch pipes (7) are all DN20.

8. The netable liquid ammonia liquid ammonia loading device according to claim 1, characterized in that, The third control valve (41) and the pressure control valve (42) are both pneumatic valves, and the fourth control valve (63) and the fifth control valve (71) are both ball valves.

Images