An ammonia gas compressor dry gas seal system

Abstract

This utility model belongs to the field of dry gas sealing technology, specifically relating to a dry gas sealing system for an ammonia compressor. It includes an ammonia compressor, with a pre-gas supply pipeline, a sealing gas supply pipeline, and an isolation gas supply pipeline connected sequentially from the inside to the outside at both ends of the compressor. The other ends of the two pre-gas supply pipelines are connected to a low-pressure nitrogen outlet, and the other ends of the two isolation gas supply pipelines are also connected to the low-pressure nitrogen outlet. Compared to existing ammonia compressors using sealing oil, this system replaces the original sealing oil pipeline with a sealing gas supply pipeline, enabling segmented sealing pressure control of the pre-gas, sealing gas, and isolation gas. This ensures smooth injection of the sealing gas, maintains safe dry gas sealing operation, solves the problem of excessive low-pressure nitrogen consumption during startup of existing ammonia compressors, and effectively reduces process gas contamination caused by oil circuit failures.

Description

Technical Field

[0001] This utility model belongs to the field of dry gas sealing technology, specifically relating to a dry gas sealing system for an ammonia compressor. Background Technology

[0002] The ammonia compressor is the heart of a large-scale ammonia synthesis plant. Existing ammonia compressor units all use mechanical seals, and the sealing oil system has a complex structure involving multi-stage oil circuit circulation and pressure regulation devices. This not only increases maintenance costs, but also makes it easy for process gas to be contaminated due to oil circuit failures, which seriously affects refrigeration efficiency and the long-term stable operation of the entire ammonia synthesis plant. Utility Model Content

[0003] This invention provides a dry gas sealing system for an ammonia compressor to address the serious oil leakage problem that occurs during the operation of the mechanical seal of the aforementioned ammonia compressor.

[0004] To achieve the above objectives, the present invention adopts the following technical solution: A dry gas sealing system for an ammonia compressor includes an ammonia compressor fixedly mounted on a main shaft. From the inside out, the two ends of the ammonia compressor are sequentially provided with a pre-port, a sealing port, and an isolation port. One end of a pre-gas supply pipeline is connected to the pre-port; one end of a sealing gas supply pipeline is connected to the sealing port; and one end of an isolation gas supply pipeline is connected to the isolation port. The other ends of the two pre-gas supply pipelines are connected to a low-pressure nitrogen outlet. A low-pressure nitrogen gate valve and a process gas gate valve are installed on the pre-gas supply pipeline. The other ends of the two sealing gas supply pipelines are connected to the low-pressure nitrogen outlet. A first nitrogen distribution valve is installed on the sealing gas supply pipeline. The other ends of the two isolation gas supply pipelines are connected to the low-pressure nitrogen outlet. A second nitrogen distribution valve and a pressure reducing valve are installed on the isolation gas supply pipeline. A process gas outlet is located between the pre-gas supply pipeline and the low-pressure nitrogen outlet, and the process gas outlet has a drain port.

[0005] Furthermore, the pre-gas supply pipeline is equipped with pre-gas, the sealing gas supply pipeline is equipped with sealing gas, and the isolation gas supply pipeline is equipped with isolation gas.

[0006] Furthermore, a condensate drain and an external leakage outlet are provided between the sealing port and the isolation port.

[0007] Furthermore, a filter device is installed between the low-pressure nitrogen outlet and the second nitrogen distribution valve.

[0008] Furthermore, two pipelines are installed at both the low-pressure nitrogen outlet and the process gas outlet, one of which is a backup pipeline.

[0009] Compared with the prior art, the present invention has the following advantages: 1. Compared with existing ammonia compressors with sealing oil, this utility model replaces the original sealing oil pipeline with a sealing gas pipeline, realizing segmented sealing pressure control of pre-gas, sealing gas and isolation gas, ensuring smooth injection of sealing gas, maintaining the safe operation of dry gas sealing, solving the problem of large consumption of low-pressure nitrogen caused by the start-up of existing ammonia compressors, and effectively reducing process gas pollution caused by oil circuit failure.

[0010] 2. The application of this utility model solves the production dilemma of severe oil leakage in the original mechanical seal of the ammonia compressor and low refrigeration effect of the synthetic refrigeration system, thereby improving the economic efficiency and environmental friendliness of the production equipment. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the structure of this utility model; In the diagram, the following components are connected: ammonia compressor 1, pre-gas supply line 2, sealing gas supply line 3, isolation gas supply line 4, low-pressure nitrogen outlet 5, process gas outlet 6, sealing port 7, nitrogen distribution valve 1 8, nitrogen distribution valve 2 9, pressure reducing valve 10, pre-gas outlet 11, low-pressure nitrogen gate valve 12, process gas gate valve 13, condensate drain 14, external leakage port 15, liquid drain 16, and isolation port 17. Detailed Implementation

[0012] To further illustrate the technical solution of this utility model, the following embodiments will be used to further explain this utility model.

[0013] like Figure 1As shown, an ammonia compressor dry gas sealing system includes an ammonia compressor 1, which is fixedly mounted on a main shaft. From the inside out, the two ends of the ammonia compressor 1 are sequentially provided with a pre-port 11, a sealing port 7, and an isolation port 17. One end of a pre-gas supply pipeline 2 is connected to the pre-port 11; one end of a sealing gas supply pipeline 3 is connected to the sealing port 7; and one end of an isolation gas supply pipeline 4 is connected to the isolation port 17. Pre-gas is contained in the pre-gas supply pipeline 2, sealing gas is contained in the sealing gas supply pipeline 3, and isolation gas is contained in the isolation gas supply pipeline 4. The other ends of the two pre-gas supply pipelines 2 are connected to a low-pressure nitrogen outlet 5. A low-pressure nitrogen gate valve 12 and a process gas gate valve are installed on the pre-gas supply pipeline 2. 13. The other ends of the two sealing gas supply lines 3 are connected to the low-pressure nitrogen outlet 5. A first nitrogen distribution valve 8 is installed on the sealing gas supply line 3. The other ends of the two isolation gas supply lines 4 are connected to the low-pressure nitrogen outlet 5. A second nitrogen distribution valve 9 and a pressure reducing valve 10 are installed on the isolation gas supply line 4. A filter device is installed between the low-pressure nitrogen outlet 5 and the second nitrogen distribution valve 9. A process gas outlet 6 is installed between the pre-gas supply line 2 and the low-pressure nitrogen outlet 5. A drain port 16 is installed on the process gas outlet 6. A condensate drain port 14 and an external leakage port 15 are installed between the sealing port 7 and the isolation port 17. Two lines are installed on both the low-pressure nitrogen outlet 5 and the process gas outlet 6, one of which is a spare line.

[0014] Work steps: 1. When starting up, use the dry gas seal control system first, and then use the unit's lubrication system. The dry gas seal control system should first use the sealing gas, and then the pre-gas. There is no restriction on the order of using the isolation gas.

[0015] 2. Operation: Before starting the lubricating oil pump, slowly open nitrogen distribution valve 9 (number 2) and pressure reducing valve 10. Low-pressure nitrogen (0.005 MPa to 0.01 MPa) is introduced from the low-pressure nitrogen outlet 5 into isolation gas supply line 4. Slowly open nitrogen distribution valve 8 (number 1), introducing sealing gas (0.5 MPa) from the low-pressure nitrogen outlet 5 into sealing gas supply line 3. Close process gas gate valve 13, and slowly open low-pressure nitrogen gate valve 12. Low-pressure nitrogen (0.5 MPa) is introduced from the low-pressure nitrogen outlet 5 into pre-gas supply line 2 as pre-gas. After the unit is running normally, open process gas gate valve 13, then close the pressure nitrogen gate valve 12, switching the pre-gas source to process gas outlet 6. During this process, 0.5... Low-pressure nitrogen gas at MPa enters the filtration device and is then divided into two paths. One path enters the isolation gas supply line 4 at both ends of the ammonia compressor and is released through the condensate drain port 14. The other path is discharged through the external discharge port.

[0016] 3. When shutting down: First, shut down the lubrication system of the unit. After confirming that the lubrication system of the unit is safe and there is no hot oil mist, close the second nitrogen distribution valve 9, pressure reducing valve 10, low-pressure nitrogen gate valve 12 and process gas gate valve 13 in sequence. Finally, close the first nitrogen distribution valve 8. If there is pressure inside the casing of the ammonia compressor, the first nitrogen distribution valve 8, low-pressure nitrogen gate valve 12 and process gas gate valve 13 cannot be closed.

[0017] The foregoing has shown and described the main features and advantages of this utility model. It will be apparent to those skilled in the art that this utility model is not limited to the details of the exemplary embodiments described above, and that it can be implemented in other specific forms without departing from the spirit or essential characteristics of this utility model. Therefore, the embodiments should be considered exemplary and non-limiting in all respects. The scope of this utility model is defined by the appended claims rather than the foregoing description, and thus all variations falling within the meaning and scope of equivalents of the claims are intended to be included within this utility model.

[0018] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. An ammonia compressor dry gas seal system characterized by: The system includes an ammonia compressor (1), which is fixedly mounted on a main shaft. From the inside out, the two ends of the ammonia compressor (1) are sequentially provided with a pre-port (11), a sealing port (7), and an isolation port (17). One end of a pre-gas supply line (2) is connected to the pre-port (11), one end of a sealing gas supply line (3) is connected to the sealing port (7), and one end of an isolation gas supply line (4) is connected to the isolation port (17). The other ends of the two pre-gas supply lines (2) are connected to a low-pressure nitrogen outlet (5). The pre-gas supply lines (2) are equipped with… The low-pressure nitrogen gate valve (12) and the process gas gate valve (13) are connected together at the other end of the two sealing gas supply lines (3) to the low-pressure nitrogen outlet (5). A first nitrogen distribution valve (8) is provided on the sealing gas supply line (3). The other end of the two isolation gas supply lines (4) is connected together to the low-pressure nitrogen outlet (5). A second nitrogen distribution valve (9) and a pressure reducing valve (10) are provided on the isolation gas supply line (4). A process gas outlet (6) is provided between the pre-gas supply line (2) and the low-pressure nitrogen outlet (5). A drain port (16) is provided on the process gas outlet (6).

2. An ammonia compressor dry gas seal system as claimed in claim 1, characterized in that: The pre-gas supply line (2) is equipped with pre-gas, the sealing gas supply line (3) is equipped with sealing gas, and the isolation gas supply line (4) is equipped with isolation gas.

3. An ammonia compressor dry gas seal system as claimed in claim 1, wherein: A condensate drain (14) and an external leakage outlet (15) are provided between the sealing port (7) and the isolation port (17).

4. An ammonia compressor dry gas seal system as claimed in claim 1, wherein: A filter is installed between the low-pressure nitrogen outlet (5) and the second nitrogen distribution valve (9).

5. An ammonia compressor dry gas seal system as claimed in claim 1, wherein: Two pipelines are provided at both the low-pressure nitrogen outlet (5) and the process gas outlet (6), one of which is a backup pipeline.

Images