Ammonia synthesis tower advanced heating system
By introducing nitrogen and hydrogen pipelines into the ammonia synthesis tower to form a mixed gas, and using low-pressure and high-pressure cylinders to pressurize the mixed gas, the problem of slow catalyst heating was solved, rapid catalyst heating was achieved, and synthesis gas venting time and resource waste were reduced.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-02-10
- Publication Date
- 2026-03-06
AI Technical Summary
When the ammonia synthesis tower is started up, the catalyst cannot be heated to above 300°C quickly, resulting in a long venting time for the syngas and a waste of resources.
By connecting nitrogen and hydrogen pipelines to form a mixed gas, the mixed gas is pressurized using low-pressure and high-pressure cylinders and then transported to the ammonia synthesis tower to achieve preheating of the catalyst.
The catalyst can rapidly heat up to over 300°C, reducing syngas venting time, avoiding resource waste, and has a simple structure, is easy to implement, and is low in cost.
Smart Images
Figure CN223969937U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of coal chemical technology, and in particular to an ammonia synthesis tower preheating system. Background Technology
[0002] Large-scale ammonia synthesis plants often employ three-bed catalytic converters for ammonia synthesis. Three-bed catalytic converters distribute the heat of reaction across multiple beds, avoiding the overheating problem caused by excessive concentration of heat in a single bed, thus helping to extend the catalyst's lifespan. Specifically, the feed synthesis gas enters from the bottom of the ammonia synthesis tower and flows upwards, flushing the tower shell to maintain a lower temperature. Upon reaching the top, it enters the central loop pipe and flows downwards to the bottom of the pipe. It then sequentially passes upwards through the tube sides of two internal heat exchangers located in the center of the second and first beds, where it is heated. It then reacts radially through the first catalyst bed. The product gas leaves the first bed, is cooled, and enters the second bed for further reaction. After cooling again, it enters the third bed for continued reaction, and finally exits from the bottom of the synthesis tower through the outlet collecting pipe.
[0003] However, during the start-up of the ammonia synthesis tower, the catalyst needs to be heated to above 300°C to become active. Heating the catalyst requires the syngas compressor to drive the hydrogen-nitrogen electric furnace. Currently, under nitrogen operation, the syngas compressor unit cannot operate stably. It can only heat the catalyst after receiving qualified hydrogen-nitrogen gas from the upstream liquid nitrogen scrubbing unit, a process that takes a long time, typically over ten hours. This results in prolonged syngas venting time and significant waste.
[0004] Therefore, it is necessary to develop an ammonia synthesis tower preheating system to solve the above problems. Utility Model Content
[0005] The purpose of this invention is to provide an ammonia synthesis tower preheating system to solve the problems of the catalyst not reaching the catalytic temperature and the long synthesis gas control time during the start-up of the ammonia synthesis tower.
[0006] This invention provides an ammonia synthesis tower preheating system.
[0007] The ammonia synthesis tower preheating system includes a low-pressure cylinder, a high-pressure cylinder, a steam turbine, a hydrogen-nitrogen mixed gas pipeline, a nitrogen pipeline, a hydrogen pipeline, and a circulating water heat exchanger. The steam turbine is connected to both the low-pressure and high-pressure cylinders and provides power to them. The hydrogen-nitrogen mixed gas pipeline is connected to the low-pressure cylinder, and the nitrogen and hydrogen pipelines are connected to form a nitrogen-hydrogen mixed gas pipeline. This nitrogen-hydrogen mixed gas pipeline is connected to the low-pressure cylinder, which is connected to the circulating water heat exchanger. The circulating water heat exchanger is connected to the high-pressure cylinder, and the high-pressure cylinder is connected to the ammonia synthesis tower via an output pipeline.
[0008] Furthermore, the low-pressure cylinder includes a first low-pressure cylinder section and a second low-pressure cylinder section, and a low-pressure cylinder circulating water heat exchanger is provided between the first low-pressure cylinder section and the second low-pressure cylinder section; the second low-pressure cylinder section is connected to the circulating water heat exchanger.
[0009] Furthermore, the hydrogen-nitrogen mixed gas pipeline is connected to one section of the low-pressure cylinder, and the nitrogen and hydrogen mixed gas pipeline is also connected to one section of the low-pressure cylinder.
[0010] Furthermore, a low-pressure cylinder inlet valve is provided at the inlet of the first section of the low-pressure cylinder.
[0011] Furthermore, a one-way valve for mixing gas is provided between the circulating water heat exchanger and the high-pressure cylinder to prevent gas backflow.
[0012] Furthermore, the high-pressure cylinder is connected to the circulating gas pipeline from the ammonia synthesis process, and a circulating gas inlet valve is provided between the high-pressure cylinder and the circulating gas pipeline; a high-pressure cylinder outlet valve is provided at the outlet of the high-pressure cylinder, and a filter is provided at the inlet of the high-pressure cylinder.
[0013] Furthermore, a pre-installed swivel head is provided on the nitrogen and hydrogen mixing pipeline.
[0014] Furthermore, a nitrogen inlet valve and a nitrogen check valve are installed on the nitrogen pipeline.
[0015] Furthermore, the hydrogen pipeline is equipped with a hydrogen inlet valve, a hydrogen check valve, and a hydrogen reserve valve.
[0016] Furthermore, the hydrogen pipeline is connected to a hydrogen pipeline from the PSA adsorption tower, and a valve is installed on the hydrogen pipeline from the PSA adsorption tower; the hydrogen pipeline from the PSA adsorption tower is connected to a hydrogen pipeline network to transport excess hydrogen to the network.
[0017] The above-mentioned method for preheating the ammonia synthesis tower using the preheating system includes the following steps:
[0018] (1) Before the fresh mixed gas with a hydrogen-nitrogen ratio of 3:1 in the hydrogen-nitrogen mixed gas pipeline is delivered to the first section of the low-pressure cylinder, the valve, hydrogen inlet valve and nitrogen inlet valve are opened at the same time. The hydrogen from the hydrogen pipeline of the PSA adsorption tower is mixed with the nitrogen in the nitrogen pipeline through the hydrogen pipeline and delivered to the inlet of the low-pressure cylinder through the nitrogen and hydrogen mixed pipeline.
[0019] (2) Open the large valve at the inlet of the low-pressure cylinder. The steam turbine provides power to the low-pressure cylinder and the high-pressure cylinder. The nitrogen and hydrogen mixture enters the first stage of the low-pressure cylinder. After being pressurized, it enters the circulating water heat exchanger of the low-pressure cylinder. After heat exchange, the nitrogen and hydrogen mixture enters the second stage of the low-pressure cylinder. After being pressurized, it enters the circulating water heat exchanger. After heat exchange, the nitrogen and hydrogen mixture enters the high-pressure cylinder through the one-way valve of the mixture and the filter at the inlet of the high-pressure cylinder.
[0020] (3) Open the large valve of the circulating gas inlet. The nitrogen and hydrogen mixture in the high-pressure cylinder is mixed with the circulating gas from the ammonia synthesis process in the circulating gas pipeline and pressurized. It is then transported to the ammonia synthesis tower through the output pipeline, so that the catalyst of the ammonia synthesis tower is heated to above 300°C in advance.
[0021] (4) When the fresh mixed gas with a hydrogen-nitrogen ratio of 3:1 from the previous process is transported to the first stage of the low-pressure cylinder in the hydrogen-nitrogen mixed gas pipeline, through the process of step (2) and step (3), the fresh mixed gas with a hydrogen-nitrogen ratio of 3:1 is finally transported to the ammonia synthesis tower. At this time, the catalyst has reached more than 300°C and can directly carry out the ammonia synthesis reaction.
[0022] (5) Close the hydrogen inlet valve and nitrogen inlet valve, and the hydrogen from the hydrogen pipeline of the PSA adsorption tower is delivered to the pipeline network.
[0023] The positive effects of this utility model are:
[0024] (1) The ammonia synthesis tower preheating system of this utility model forms a mixed gas by connecting a nitrogen pipeline and a hydrogen pipeline, and starts the low-pressure cylinder and high-pressure cylinder in advance to pressurize the mixed gas and deliver it to the ammonia synthesis tower, so that the catalyst of the ammonia synthesis tower is preheated to above 300°C.
[0025] (2) By using the ammonia synthesis tower preheating system described in this utility model, when the fresh mixed gas with a hydrogen-nitrogen ratio of 3:1 from the previous process is transported to the first stage of the low-pressure cylinder in the hydrogen-nitrogen mixed gas pipeline, through the process of steps (2) and (3), the fresh mixed gas with a hydrogen-nitrogen ratio of 3:1 is finally transported to the ammonia synthesis tower. At this time, the catalyst has reached more than 300°C and can directly carry out the ammonia synthesis reaction, avoiding the waste of fresh mixed gas resources caused by the catalyst not reaching the catalytic temperature because the fresh mixed gas with a hydrogen-nitrogen ratio of 3:1 from the previous process cannot carry out the ammonia synthesis reaction.
[0026] (3) The ammonia synthesis tower preheating system described in this utility model has a simple structure and ingenious design, making it more suitable for widespread application.
[0027] (4) The method of preheating the ammonia synthesis tower using the preheating system of the ammonia synthesis tower described in this utility model is simple, easy to implement, efficient and low in cost. By preheating the ammonia synthesis tower, once the fresh mixed gas with a hydrogen-nitrogen ratio of 3:1 from the previous process is delivered to the low-pressure cylinder, the ammonia synthesis tower can immediately receive the gas and produce liquid ammonia, which greatly reduces waste. Attached Figure Description
[0028] The accompanying drawings are provided to better understand this solution and do not constitute a limitation of this disclosure. Wherein:
[0029] Figure 1 This is a schematic diagram of the ammonia synthesis tower preheating system described in this utility model.
[0030] The components include: 1. Low-pressure cylinder; 11. Low-pressure cylinder section 1; 12. Low-pressure cylinder section 2; 13. Low-pressure cylinder circulating water heat exchanger; 14. Low-pressure cylinder inlet valve; 2. High-pressure cylinder; 20. Output pipeline; 21. Circulating gas pipeline; 22. Circulating gas inlet valve; 23. High-pressure cylinder outlet valve; 24. Filter; 3. Steam turbine; 4. Hydrogen-nitrogen mixed gas pipeline; 5. Nitrogen pipeline; 51. Nitrogen inlet valve; 52. Nitrogen check valve; 6. Hydrogen pipeline; 61. Hydrogen inlet valve; 62. Hydrogen check valve; 63. Hydrogen reserved swivel head; 64. Hydrogen pipeline from PSA adsorption tower; 641. Valve; 7. Circulating water heat exchanger; 71. Mixed gas check valve; 56. Nitrogen and hydrogen mixed gas pipeline; 561. Reserved swivel head. Detailed Implementation
[0031] The exemplary embodiments of this disclosure are described below with reference to the accompanying drawings, including various details of the embodiments to aid understanding, and should be considered merely exemplary. Therefore, those skilled in the art will recognize that various changes and modifications can be made to the embodiments described herein without departing from the scope and spirit of this disclosure. Similarly, for clarity and brevity, descriptions of well-known functions and structures are omitted in the following description.
[0032] In a first aspect, this utility model provides an ammonia synthesis tower preheating system, comprising a low-pressure cylinder 1, a high-pressure cylinder 2, a steam turbine 3, a hydrogen-nitrogen mixed gas pipeline 4, a nitrogen pipeline 5, a hydrogen pipeline 6, and a circulating water heat exchanger 7; the steam turbine 3 is connected to the low-pressure cylinder 1 and the high-pressure cylinder 2 respectively, and provides power to the low-pressure cylinder 1 and the high-pressure cylinder 2; the hydrogen-nitrogen mixed gas pipeline 4 is connected to the low-pressure cylinder 1, the nitrogen pipeline 5 is connected to the hydrogen pipeline 6 to form a nitrogen and hydrogen mixed gas pipeline 56, the nitrogen and hydrogen mixed gas pipeline 56 is provided with a reserved swivel head 561, the nitrogen and hydrogen mixed gas pipeline 56 is connected to the low-pressure cylinder 1, the low-pressure cylinder 1 is connected to the circulating water heat exchanger 7, the circulating water heat exchanger 7 is connected to the high-pressure cylinder 2, and the high-pressure cylinder 2 is connected to the ammonia synthesis tower through an output pipeline 20.
[0033] The low-pressure cylinder 1 includes a first low-pressure cylinder section 11 and a second low-pressure cylinder section 12. A low-pressure cylinder circulating water heat exchanger 13 is installed between the first low-pressure cylinder section 11 and the second low-pressure cylinder section 12. The second low-pressure cylinder section 12 is connected to the circulating water heat exchanger 7. The hydrogen-nitrogen mixed gas pipeline 4 is connected to the first low-pressure cylinder section 11, and the nitrogen and hydrogen mixed gas pipeline 56 is connected to the first low-pressure cylinder section 11. A low-pressure cylinder inlet valve 14 is installed at the inlet of the first low-pressure cylinder section 11. A mixed gas check valve 71 is installed between the circulating water heat exchanger 7 and the high-pressure cylinder 2 to prevent gas backflow.
[0034] The high-pressure cylinder 2 is connected to the circulating gas pipeline 21 from the ammonia synthesis process. A circulating gas inlet valve 22 is provided between the high-pressure cylinder 2 and the circulating gas pipeline 21. A high-pressure cylinder outlet valve 23 is provided at the outlet of the high-pressure cylinder 2. A filter 24 is provided at the inlet of the high-pressure cylinder 2.
[0035] The nitrogen pipeline 5 is equipped with a nitrogen inlet valve 51 and a nitrogen check valve 52; the hydrogen pipeline 6 is equipped with a hydrogen inlet valve 61, a hydrogen check valve 62, and a hydrogen reserve outlet 63. The hydrogen pipeline 6 is connected to a hydrogen pipeline 64 from the PSA adsorption tower, and the hydrogen pipeline 64 from the PSA adsorption tower is equipped with a valve 641; the hydrogen pipeline 64 from the PSA adsorption tower is connected to the hydrogen pipeline network to transport excess hydrogen to the network.
[0036] The method for preheating an ammonia synthesis tower using the preheating system of this invention includes the following steps:
[0037] (1) Before the fresh mixed gas with a hydrogen-nitrogen ratio of 3:1 in the hydrogen-nitrogen mixed gas pipeline 4 is delivered to the first stage 11 of the low-pressure cylinder, valve 641, hydrogen inlet valve 61 and nitrogen inlet valve 51 are opened at the same time. Hydrogen from the hydrogen pipeline 64 of the PSA adsorption tower is mixed with nitrogen in the nitrogen pipeline 5 through the hydrogen pipeline 6 and delivered to the inlet of the low-pressure cylinder 1 through the nitrogen and hydrogen mixed pipeline 56.
[0038] (2) Open the low-pressure cylinder inlet valve 14. The steam turbine 3 provides power to the low-pressure cylinder 1 and the high-pressure cylinder 2. The nitrogen and hydrogen mixture enters the first stage 11 of the low-pressure cylinder and enters the low-pressure cylinder circulating water heat exchanger 13 after being pressurized. After heat exchange, the nitrogen and hydrogen mixture enters the second stage 12 of the low-pressure cylinder and enters the circulating water heat exchanger 7 after being pressurized. After heat exchange, the nitrogen and hydrogen mixture enters the high-pressure cylinder 2 through the mixed gas check valve 71 and the filter 24 at the inlet of the high-pressure cylinder 2.
[0039] (3) Open the circulating gas inlet valve 22. The nitrogen and hydrogen mixture in the high-pressure cylinder 2 is mixed with the circulating gas from the ammonia synthesis process in the circulating gas pipeline 21 and pressurized. It is then transported to the ammonia synthesis tower through the output pipeline 20, so that the catalyst of the ammonia synthesis tower is heated to above 300°C in advance.
[0040] (4) When the fresh mixed gas with a hydrogen-nitrogen ratio of 3:1 from the previous process is transported to the first stage of the low-pressure cylinder 11 in the hydrogen-nitrogen mixed gas pipeline 4, through the process of steps (2) and (3), the fresh mixed gas with a hydrogen-nitrogen ratio of 3:1 is finally transported to the ammonia synthesis tower. At this time, the catalyst has reached more than 300°C and can directly carry out the ammonia synthesis reaction.
[0041] (5) Close the hydrogen inlet valve 61 and the nitrogen inlet valve 51, and the hydrogen from the hydrogen pipeline 64 of the PSA adsorption tower is delivered to the pipeline network.
[0042] Example 1
[0043] A preheating system for an ammonia synthesis tower, see Figure 1The system includes a low-pressure cylinder 1, a high-pressure cylinder 2, a steam turbine 3, a hydrogen-nitrogen mixed gas pipeline 4, a nitrogen pipeline 5, a hydrogen pipeline 6, and a circulating water heat exchanger 7. The low-pressure cylinder 1 comprises a first low-pressure cylinder section 11 and a second low-pressure cylinder section 12. A low-pressure cylinder inlet valve 14 is installed at the inlet of the first low-pressure cylinder section 11, and a low-pressure cylinder circulating water heat exchanger 13 is installed between the first low-pressure cylinder section 11 and the second low-pressure cylinder section 12. The steam turbine 3 is connected to both the low-pressure cylinder 1 and the high-pressure cylinder 2, providing power to both. The hydrogen-nitrogen mixed gas pipeline 4 is connected to the first low-pressure cylinder section 11. The nitrogen pipeline 5 is equipped with a nitrogen inlet valve 51 and a nitrogen check valve 52. The hydrogen pipeline 6 is equipped with a hydrogen inlet valve 61, a hydrogen check valve 62, and a hydrogen pre-installed valve head 63. The hydrogen pipeline 6 is connected to the hydrogen pipeline 64 from the PSA adsorption tower, and the hydrogen pipeline 64 from the PSA adsorption tower is equipped with a valve 641. The hydrogen pipeline 64 from the PSA adsorption tower is connected to the hydrogen pipeline network to transport excess hydrogen to the network. The nitrogen pipeline 5 is connected to the hydrogen pipeline 6 to form a nitrogen and hydrogen mixing pipeline 56, and the nitrogen and hydrogen mixing pipeline 56 is equipped with a reserved swivel head 561. The nitrogen and hydrogen mixing pipeline 56 is connected to the first section 11 of the low-pressure cylinder, the second section 12 of the low-pressure cylinder is connected to the circulating water heat exchanger 7, the circulating water heat exchanger 7 is connected to the high-pressure cylinder 2, and a one-way valve 71 for preventing gas backflow is provided between the circulating water heat exchanger 7 and the high-pressure cylinder 2. The high-pressure cylinder 2 is connected to the circulating gas pipeline 21 from the ammonia synthesis process. A circulating gas inlet valve 22 is installed between the high-pressure cylinder 2 and the circulating gas pipeline 21. A filter 24 is installed at the inlet of the high-pressure cylinder 2, and a high-pressure cylinder outlet valve 23 is installed at the outlet of the high-pressure cylinder 2. The high-pressure cylinder 2 is connected to the ammonia synthesis tower through an output pipeline 20.
[0044] The method for preheating an ammonia synthesis tower using the preheating system described in this embodiment includes the following steps:
[0045] (1) Before the fresh mixed gas with a hydrogen-nitrogen ratio of 3:1 in the hydrogen-nitrogen mixed gas pipeline 4 is delivered to the first stage 11 of the low-pressure cylinder, valve 641, hydrogen inlet valve 61 and nitrogen inlet valve 51 are opened at the same time. The 30℃ 3.3MPa hydrogen from the hydrogen pipeline 64 of the PSA adsorption tower is mixed with the 0.4MPa nitrogen in the nitrogen pipeline 5 through the hydrogen pipeline 6 (hydrogen-nitrogen ratio of 3:1) and delivered to the inlet of the low-pressure cylinder 1 through the nitrogen and hydrogen mixed pipeline 56.
[0046] (2) Open the low-pressure cylinder inlet valve 14. The steam turbine 3 provides power to the low-pressure cylinder 1 and the high-pressure cylinder 2. The nitrogen and hydrogen mixture enters the first stage 11 of the low-pressure cylinder, is pressurized to 5.39 MPa and 86.7°C, and then enters the low-pressure cylinder circulating water heat exchanger 13. After heat exchange, the nitrogen and hydrogen mixture enters the second stage 12 of the low-pressure cylinder, is pressurized to 8.495 MPa and 96°C, and then enters the circulating water heat exchanger 7. After heat exchange, the nitrogen and hydrogen mixture (8.47 MPa and 40°C) enters the high-pressure cylinder 2 through the mixed gas check valve 71 and the filter 24 at the inlet of the high-pressure cylinder 2.
[0047] (3) Open the circulating gas inlet valve 22. The nitrogen and hydrogen mixture in the high-pressure cylinder 2 is mixed with the circulating gas from the ammonia synthesis process at 13.28 MPa and 24°C in the circulating gas pipeline 21 and then pressurized to 14.0 MPa and 52°C. It is then transported to the ammonia synthesis tower through the output pipeline 20, so that the catalyst in the ammonia synthesis tower is heated to above 300°C in advance.
[0048] (4) When the fresh mixed gas with a hydrogen-nitrogen ratio of 3:1 from the previous process, at 30°C and 3.3 MPa, is transported from the hydrogen-nitrogen mixed gas pipeline 4 to the first stage of the low-pressure cylinder 11, it is pressurized to 5.39 MPa and 86.7°C and then enters the circulating water heat exchanger 13 of the low-pressure cylinder. After heat exchange, the fresh mixed gas enters the second stage of the low-pressure cylinder 12, is pressurized to 8.495 MPa and 96°C and then enters the circulating water heat exchanger 7. After heat exchange, the fresh mixed gas at 8.47 MPa and 40°C is obtained and enters the high-pressure cylinder 2 through the mixed gas check valve 71 and the filter 24 at the inlet of the high-pressure cylinder 2. The fresh mixed gas in the high-pressure cylinder 2 is mixed with the circulating gas from the ammonia synthesis process at 13.28 MPa and 24°C in the circulating gas pipeline 21 and then pressurized to 14.0 MPa and 52°C. The pressurized fresh mixed gas is then transported to the ammonia synthesis tower through the output pipeline 20. At this time, the catalyst has reached more than 300°C and can directly carry out the ammonia synthesis reaction.
[0049] (5) Close the hydrogen inlet valve 61 and the nitrogen inlet valve 51, and the hydrogen from the hydrogen pipeline 64 of the PSA adsorption tower is delivered to the pipeline network.
[0050] Example 2
[0051] A preheating system for an ammonia synthesis tower includes a low-pressure cylinder 1, a high-pressure cylinder 2, a steam turbine 3, a hydrogen-nitrogen mixed gas pipeline 4, a nitrogen pipeline 5, a hydrogen pipeline 6, and a circulating water heat exchanger 7. The steam turbine 3 is connected to both the low-pressure cylinder 1 and the high-pressure cylinder 2, and provides power to both cylinders. The hydrogen-nitrogen mixed gas pipeline 4 is connected to the low-pressure cylinder 1, and the nitrogen pipeline 5 is connected to the hydrogen pipeline 6 to form a nitrogen and hydrogen mixed gas pipeline 56. The nitrogen and hydrogen mixed gas pipeline 56 is connected to the low-pressure cylinder 1, the low-pressure cylinder 1 is connected to the circulating water heat exchanger 7, the circulating water heat exchanger 7 is connected to the high-pressure cylinder 2, and the high-pressure cylinder 2 is connected to the ammonia synthesis tower via an output pipeline 20.
[0052] Example 3
[0053] A preheating system for an ammonia synthesis tower includes a low-pressure cylinder 1, a high-pressure cylinder 2, a steam turbine 3, a hydrogen-nitrogen mixed gas pipeline 4, a nitrogen pipeline 5, a hydrogen pipeline 6, and a circulating water heat exchanger 7. The low-pressure cylinder 1 comprises a first low-pressure cylinder section 11 and a second low-pressure cylinder section 12. A large inlet valve 14 is installed at the inlet of the first low-pressure cylinder section 11, and a circulating water heat exchanger 13 is installed between the first low-pressure cylinder section 11 and the second low-pressure cylinder section 12. The steam turbine 3 is connected to both the low-pressure cylinder 1 and the high-pressure cylinder 2, providing power to both. The hydrogen-nitrogen mixed gas pipeline... 4 is connected to the first section 11 of the low-pressure cylinder. The nitrogen pipeline 5 is connected to the hydrogen pipeline 6 to form a nitrogen and hydrogen mixing pipeline 56. A reserved swivel head 561 is provided on the nitrogen and hydrogen mixing pipeline 56. The nitrogen and hydrogen mixing pipeline 56 is connected to the first section 11 of the low-pressure cylinder. The second section 12 of the low-pressure cylinder is connected to the circulating water heat exchanger 7. The circulating water heat exchanger 7 is connected to the high-pressure cylinder 2. A one-way valve 71 for preventing gas backflow is provided between the circulating water heat exchanger 7 and the high-pressure cylinder 2. The high-pressure cylinder 2 is connected to the ammonia synthesis tower through the output pipeline 20.
[0054] Example 4
[0055] A preheating system for an ammonia synthesis tower includes a low-pressure cylinder 1, a high-pressure cylinder 2, a steam turbine 3, a hydrogen-nitrogen mixed gas pipeline 4, a nitrogen pipeline 5, a hydrogen pipeline 6, and a circulating water heat exchanger 7. The low-pressure cylinder 1 comprises a first low-pressure cylinder section 11 and a second low-pressure cylinder section 12. A large inlet valve 14 is installed at the inlet of the first low-pressure cylinder section 11, and a circulating water heat exchanger 13 is installed between the first low-pressure cylinder section 11 and the second low-pressure cylinder section 12. The steam turbine 3 is connected to both the low-pressure cylinder 1 and the high-pressure cylinder 2, and provides power to both cylinders. The hydrogen-nitrogen mixed gas pipeline 4 is connected to the first section 11 of the low-pressure cylinder, and the nitrogen pipeline 5 is connected to the hydrogen pipeline 6 to form a nitrogen and hydrogen mixed gas pipeline 56. A reserved swivel head 561 is provided on the nitrogen and hydrogen mixed gas pipeline 56. The nitrogen and hydrogen mixed gas pipeline 56 is connected to the first section 11 of the low-pressure cylinder, and the second section 12 of the low-pressure cylinder is connected to the circulating water heat exchanger 7. The circulating water heat exchanger 7 is connected to the high-pressure cylinder 2, and a one-way valve 71 for preventing gas backflow is provided between the circulating water heat exchanger 7 and the high-pressure cylinder 2.
[0056] The high-pressure cylinder 2 is connected to the circulating gas pipeline 21 from the ammonia synthesis process. A circulating gas inlet valve 22 is installed between the high-pressure cylinder 2 and the circulating gas pipeline 21. A filter 24 is installed at the inlet of the high-pressure cylinder 2, and a high-pressure cylinder outlet valve 23 is installed at the outlet of the high-pressure cylinder 2. The high-pressure cylinder 2 is connected to the ammonia synthesis tower through an output pipeline 20.
[0057] Example 5
[0058] A preheating system for an ammonia synthesis tower includes a low-pressure cylinder 1, a high-pressure cylinder 2, a steam turbine 3, a hydrogen-nitrogen mixed gas pipeline 4, a nitrogen pipeline 5, a hydrogen pipeline 6, and a circulating water heat exchanger 7. The low-pressure cylinder 1 includes a first low-pressure cylinder section 11 and a second low-pressure cylinder section 12. A large inlet valve 14 is installed at the inlet of the first low-pressure cylinder section 11, and a circulating water heat exchanger 13 is installed between the first low-pressure cylinder section 11 and the second low-pressure cylinder section 12. The steam turbine 3 is connected to the... The low-pressure cylinder 1 and the high-pressure cylinder 2 are connected, and the high-pressure cylinder 2 is powered by the low-pressure cylinder 1 and the high-pressure cylinder 2. The hydrogen-nitrogen mixed gas pipeline 4 is connected to the first section 11 of the low-pressure cylinder. The nitrogen pipeline 5 is connected to the hydrogen pipeline 6 to form a nitrogen and hydrogen mixed gas pipeline 56. The nitrogen and hydrogen mixed gas pipeline 56 is connected to the first section 11 of the low-pressure cylinder. The second section 12 of the low-pressure cylinder is connected to the circulating water heat exchanger 7. The circulating water heat exchanger 7 is connected to the high-pressure cylinder 2. The high-pressure cylinder 2 is connected to the circulating gas pipeline 21 from the ammonia synthesis process. The high-pressure cylinder 2 is connected to the ammonia synthesis tower through the output pipeline 20.
[0059] Example 6
[0060] A preheating system for an ammonia synthesis tower includes a low-pressure cylinder 1, a high-pressure cylinder 2, a steam turbine 3, a hydrogen-nitrogen mixed gas pipeline 4, a nitrogen pipeline 5, a hydrogen pipeline 6, and a circulating water heat exchanger 7. The low-pressure cylinder 1 comprises a first low-pressure cylinder section 11 and a second low-pressure cylinder section 12. A low-pressure cylinder inlet valve 14 is installed at the inlet of the first low-pressure cylinder section 11, and a low-pressure cylinder circulating water heat exchanger 13 is installed between the first low-pressure cylinder section 11 and the second low-pressure cylinder section 12. The steam turbine 3 is connected to both the low-pressure cylinder 1 and the high-pressure cylinder 2, providing power to both. The hydrogen-nitrogen mixed gas pipeline 4 is connected to the first low-pressure cylinder section 11. The nitrogen pipeline 5 is equipped with a nitrogen inlet valve 51 and a nitrogen check valve 52. The hydrogen pipeline 6 is equipped with a hydrogen inlet valve 61, a hydrogen check valve 62, and a hydrogen pre-installed valve head 63. The nitrogen pipeline 5 and hydrogen pipeline 6 are connected to form a nitrogen and hydrogen mixing pipeline 56. A pre-installed swivel head 561 is provided on the nitrogen and hydrogen mixing pipeline 56. The nitrogen and hydrogen mixing pipeline 56 is connected to the first section 11 of the low-pressure cylinder. The second section 12 of the low-pressure cylinder is connected to the circulating water heat exchanger 7. The circulating water heat exchanger 7 is connected to the high-pressure cylinder 2. A one-way valve 71 for preventing gas backflow is provided between the circulating water heat exchanger 7 and the high-pressure cylinder 2. The high-pressure cylinder 2 is connected to the circulating gas pipeline 21 from the ammonia synthesis process. A circulating gas inlet valve 22 is provided between the high-pressure cylinder 2 and the circulating gas pipeline 21. A filter 24 is provided at the inlet of the high-pressure cylinder 2, and a high-pressure cylinder outlet valve 23 is provided at the outlet of the high-pressure cylinder 2. The high-pressure cylinder 2 is connected to the ammonia synthesis tower via an output pipeline 20.
[0061] Example 7
[0062] A preheating system for an ammonia synthesis tower includes a low-pressure cylinder 1, a high-pressure cylinder 2, a steam turbine 3, a hydrogen-nitrogen mixed gas pipeline 4, a nitrogen pipeline 5, a hydrogen pipeline 6, and a circulating water heat exchanger 7. The low-pressure cylinder 1 comprises a first low-pressure cylinder section 11 and a second low-pressure cylinder section 12. A low-pressure cylinder inlet valve 14 is installed at the inlet of the first low-pressure cylinder section 11, and a low-pressure cylinder circulating water heat exchanger 13 is installed between the first low-pressure cylinder section 11 and the second low-pressure cylinder section 12. The steam turbine 3 is connected to both the low-pressure cylinder 1 and the high-pressure cylinder 2, providing power to both. The hydrogen-nitrogen mixed gas pipeline 4 is connected to the first low-pressure cylinder section 11. The nitrogen pipeline 5 is equipped with a nitrogen inlet valve 51 and a nitrogen check valve 52. The hydrogen pipeline 6 is equipped with a hydrogen inlet valve 61, a hydrogen check valve 62, and a hydrogen pre-installed valve head 63. The nitrogen pipeline 5 and the hydrogen pipeline 6 are connected to form a nitrogen and hydrogen mixing pipeline 56. The nitrogen and hydrogen mixing pipeline 56 is connected to the first section 11 of the low-pressure cylinder, and the second section 12 of the low-pressure cylinder is connected to the circulating water heat exchanger 7. The circulating water heat exchanger 7 is connected to the high-pressure cylinder 2. The high-pressure cylinder 2 is connected to the circulating gas pipeline 21 from the ammonia synthesis process. A circulating gas inlet valve 22 is installed between the high-pressure cylinder 2 and the circulating gas pipeline 21. A filter 24 is installed at the inlet of the high-pressure cylinder 2. The high-pressure cylinder 2 is connected to the ammonia synthesis tower through the output pipeline 20.
[0063] Example 8
[0064] A method for preheating an ammonia synthesis tower includes the following steps:
[0065] (1) Before the fresh mixed gas with a hydrogen-nitrogen ratio of 3:1 in the hydrogen-nitrogen mixed gas pipeline 4 is delivered to the first stage 11 of the low-pressure cylinder, valve 641, hydrogen inlet valve 61 and nitrogen inlet valve 51 are opened at the same time. Hydrogen from the hydrogen pipeline 64 of the PSA adsorption tower is mixed with nitrogen in the nitrogen pipeline 5 through the hydrogen pipeline 6 and delivered to the inlet of the low-pressure cylinder 1 through the nitrogen and hydrogen mixed pipeline 56.
[0066] (2) Open the low-pressure cylinder inlet valve 14. The steam turbine 3 provides power to the low-pressure cylinder 1 and the high-pressure cylinder 2. The nitrogen and hydrogen mixture enters the first stage 11 of the low-pressure cylinder and enters the low-pressure cylinder circulating water heat exchanger 13 after being pressurized. After heat exchange, the nitrogen and hydrogen mixture enters the second stage 12 of the low-pressure cylinder and enters the circulating water heat exchanger 7 after being pressurized. After heat exchange, the nitrogen and hydrogen mixture enters the high-pressure cylinder 2 through the mixed gas check valve 71 and the filter 24 at the inlet of the high-pressure cylinder 2.
[0067] (3) Open the circulating gas inlet valve 22. The nitrogen and hydrogen mixture in the high-pressure cylinder 2 is mixed with the circulating gas from the ammonia synthesis process in the circulating gas pipeline 21 and pressurized. It is then transported to the ammonia synthesis tower through the output pipeline 20, so that the catalyst of the ammonia synthesis tower is heated to above 300°C in advance.
[0068] (4) When the fresh mixed gas with a hydrogen-nitrogen ratio of 3:1 from the previous process is transported to the first stage of the low-pressure cylinder 11 in the hydrogen-nitrogen mixed gas pipeline 4, through the process of steps (2) and (3), the fresh mixed gas with a hydrogen-nitrogen ratio of 3:1 is finally transported to the ammonia synthesis tower. At this time, the catalyst has reached more than 300°C and can directly carry out the ammonia synthesis reaction.
[0069] (5) Close the hydrogen inlet valve 61 and the nitrogen inlet valve 51, and the hydrogen from the hydrogen pipeline 64 of the PSA adsorption tower is delivered to the pipeline network.
[0070] The ammonia synthesis tower preheating system of this invention has a simple structure and ingenious design, making it more suitable for widespread application. The ammonia synthesis tower preheating method of this invention is simple, easy to implement, highly efficient, and low in cost. The ammonia synthesis tower preheating system of this invention forms a mixed gas by connecting nitrogen pipeline 5 and hydrogen pipeline 6, and pre-starts low-pressure cylinder 1 and high-pressure cylinder 2 to pressurize the mixed gas, which is then transported to the ammonia synthesis tower, so that the catalyst of the ammonia synthesis tower is preheated to above 300°C. When the fresh mixed gas with a hydrogen-nitrogen ratio of 3:1 from the previous process is transported to the first stage 11 of the low-pressure cylinder in the hydrogen-nitrogen mixed gas pipeline 4, through the processes of steps (2) and (3), the fresh mixed gas with a hydrogen-nitrogen ratio of 3:1 is finally transported to the ammonia synthesis tower. At this time, the catalyst has reached above 300°C and can directly carry out the ammonia synthesis reaction, avoiding the waste of fresh mixed gas resources caused by the catalyst not reaching the catalytic temperature in the fresh mixed gas with a hydrogen-nitrogen ratio of 3:1 from the previous process.
[0071] It should be understood that the ammonia synthesis tower preheating system and method described above can be used, with steps rearranged, added, or deleted. This utility model does not impose any limitations on the outcome as long as the desired result of the disclosed technical solution can be achieved.
[0072] The specific embodiments described above do not constitute a limitation on the scope of protection disclosed in this utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the scope of protection disclosed in this utility model.
Claims
1. An ammonia converter pre-warming system characterized by: The application relates to a hydrogen-nitrogen mixed gas pipeline, a nitrogen pipeline, a hydrogen pipeline and a circulating water heat exchanger.
2. The ammonia converter pre-heat-up system of claim 1, wherein: The low-pressure cylinder (1) comprises a low-pressure cylinder first section (11) and a low-pressure cylinder second section (12), and a low-pressure cylinder circulating water heat exchanger (13) is arranged between the low-pressure cylinder first section (11) and the low-pressure cylinder second section (12); the low-pressure cylinder second section (12) is connected with the circulating water heat exchanger (7).
3. The ammonia converter pre-heat-up system of claim 2, wherein: The hydrogen-nitrogen mixed gas pipeline (4) is connected with the low-pressure cylinder first section (11), and the nitrogen-hydrogen mixed pipeline (56) is connected with the low-pressure cylinder first section (11).
4. The ammonia converter pre-heat-up system of claim 2, wherein: A low-pressure cylinder inlet large valve (14) is arranged at the inlet of the low-pressure cylinder first section (11).
5. The ammonia converter pre-heat-up system of claim 1, wherein: A mixed gas one-way valve (71) for preventing gas backflow is arranged between the circulating water heat exchanger (7) and the high-pressure cylinder (2).
6. The ammonia converter pre-heat-up system of claim 1, wherein: The high-pressure cylinder (2) is connected with a circulating gas pipeline (21) from an ammonia synthesis process, a circulating gas inlet large valve (22) is arranged between the high-pressure cylinder (2) and the circulating gas pipeline (21); an outlet of the high-pressure cylinder (2) is provided with a high-pressure cylinder outlet large valve (23), and a filter (24) is arranged at the inlet of the high-pressure cylinder (2).
7. The ammonia converter pre-heat-up system of claim 1, wherein: A reserved flange (561) is arranged on the nitrogen-hydrogen mixed pipeline (56).
8. The ammonia converter pre-heat-up system of claim 1, wherein: A nitrogen inlet valve (51) and a nitrogen one-way valve (52) are arranged on the nitrogen pipeline (5).
9. The ammonia converter pre-heat-up system of claim 1, wherein: A hydrogen inlet valve (61), a hydrogen one-way valve (62) and a hydrogen reserved flange (63) are arranged on the hydrogen pipeline (6).
10. The ammonia converter pre-heat-up system of claim 1, wherein: The hydrogen pipeline (6) is connected with a hydrogen pipeline (64) from a PSA adsorption tower, a valve (641) is arranged on the hydrogen pipeline (64) from the PSA adsorption tower; the hydrogen pipeline (64) from the PSA adsorption tower is connected with a hydrogen pipeline network, and surplus hydrogen is transported to the pipeline network.