Ammonia Refrigeration System

Abstract

The embodiment of the present application provides an ammonia refrigeration system, which belongs to the technical field of nitrogen fertilizer preparation. The ammonia refrigeration system includes an ammonia receiving tank, an ammonia cooler group, a gas-ammonia separator, a liquid ammonia storage tank, an ammonia compressor, an ammonia booster, a gas-ammonia cooler and an ammonia synthesis device. The outlet of the ammonia receiving tank is connected to the inlet of the shell side of the ammonia cooler group, the liquid ammonia outlet of the shell side of the ammonia cooler group is connected to the inlet of the gas-ammonia separator, and the liquid ammonia outlet of the gas-ammonia separator is connected to the liquid ammonia storage tank. The gas-ammonia outlet of the shell side of the ammonia cooler group is connected to the inlet of the ammonia compressor, the outlet of the ammonia compressor is connected to the inlet of the gas-ammonia cooler, the gas-ammonia outlet of the gas-ammonia separator is connected to the inlet of the ammonia booster, the outlet of the ammonia booster is connected to the inlet of the gas-ammonia cooler, and the outlet of the gas-ammonia cooler is connected to the inlet of the ammonia receiving tank; the outlet of the ammonia synthesis device is connected to the inlet of the shell side of the ammonia cooler group. The use of this ammonia refrigeration system can effectively save energy.

Description

Technical Field

[0001] The present application relates to the technical field of nitrogen fertilizer preparation, and in particular to an ammonia refrigeration system. Background Art

[0002] In recent years, the development level of my country's fertilizer industry has continued to improve. As one of the most important links in nitrogen fertilizer technology, the synthetic ammonia process has received widespread attention.

[0003] Under cold ammonia conditions, the high-pressure liquid ammonia generated by the synthetic ammonia unit needs to be input into the gas-ammonia separator for flash evaporation. After flash evaporation, part of the high-pressure liquid ammonia is converted into normal-pressure liquid ammonia, and the other part of the high-pressure liquid ammonia is converted into normal-pressure gas ammonia. Normal-pressure liquid ammonia can be directly sent to the ammonia tank area, while normal-pressure gas ammonia is input into the ammonia booster for pressure increase, then liquefied into liquid ammonia, and then re-entered into the gas-ammonia separator for flash evaporation.

[0004] In the above process, part of the high-pressure liquid ammonia is directly converted into atmospheric-pressure gaseous ammonia, and atmospheric-pressure gaseous ammonia needs to be raised from atmospheric pressure to high pressure through an ammonia booster, which wastes a lot of energy. Summary of the invention

[0005] The embodiment of the present application provides an ammonia refrigeration system, which can solve the technical problems existing in the related technology. The technical solution of the ammonia refrigeration system is as follows:

[0006] The embodiment of the present application provides an ammonia refrigeration system, which includes an ammonia receiving tank, an ammonia cooler group, a gas-ammonia separator, a liquid ammonia storage tank, an ammonia compressor, an ammonia booster, a gas-ammonia cooler and an ammonia synthesis device;

[0007] The outlet of the ammonia receiving tank is connected to the inlet of the shell side of the ammonia cooler group, the liquid ammonia outlet of the shell side of the ammonia cooler group is connected to the inlet of the gas-ammonia separator, and the liquid ammonia outlet of the gas-ammonia separator is connected to the liquid ammonia storage tank;

[0008] The gas ammonia outlet of the shell side of the ammonia cooler group is connected to the inlet of the ammonia compressor, the outlet of the ammonia compressor is connected to the inlet of the gas ammonia cooler, the gas ammonia outlet of the gas ammonia separator is connected to the inlet of the ammonia booster, the outlet of the ammonia booster is connected to the inlet of the gas ammonia cooler, and the outlet of the gas ammonia cooler is connected to the inlet of the ammonia receiving tank;

[0009] The outlet of the ammonia synthesis device is connected to the inlet of the shell side of the ammonia cooler group.

[0010] In a possible implementation, the ammonia cooler group includes a primary ammonia cooler and a secondary ammonia cooler;

[0011] The shell side inlet of the primary ammonia cooler is connected to the outlet of the ammonia receiving tank, the shell side liquid ammonia outlet of the primary ammonia cooler is connected to the shell side inlet of the secondary ammonia cooler, and the shell side liquid ammonia outlet of the secondary ammonia cooler is connected to the inlet of the gas-ammonia separator;

[0012] The gas ammonia outlets of the primary ammonia cooler and the secondary ammonia cooler are both connected to the inlet of the ammonia compressor;

[0013] The outlet of the ammonia synthesis device is connected to the inlet of the shell side of the first-stage ammonia cooler and the inlet of the shell side of the second-stage ammonia cooler respectively.

[0014] In a possible implementation, a first control valve is provided on the connecting pipeline between the outlet of the ammonia synthesis device and the inlet of the shell side of the primary ammonia cooler;

[0015] A second control valve is provided on the connecting pipeline between the outlet of the ammonia synthesis device and the inlet of the shell side of the secondary ammonia cooler.

[0016] In a possible implementation, the first control valve and the second control valve are configured to adjust valve openings based on the liquid level of liquid ammonia in the ammonia synthesis device.

[0017] In a possible implementation, the ammonia cooler group includes a primary ammonia cooler and a secondary ammonia cooler;

[0018] The shell side inlet of the primary ammonia cooler is connected to the outlet of the ammonia receiving tank, the shell side liquid ammonia outlet of the primary ammonia cooler is connected to the shell side inlet of the secondary ammonia cooler, and the shell side liquid ammonia outlet of the secondary ammonia cooler is connected to the inlet of the gas-ammonia separator;

[0019] The gas ammonia outlets of the primary ammonia cooler and the secondary ammonia cooler are both connected to the inlet of the ammonia compressor;

[0020] The outlet of the ammonia synthesis device is connected to the inlet of the shell side of the primary ammonia cooler.

[0021] In a possible implementation, the ammonia cooler group includes a primary ammonia cooler and a secondary ammonia cooler;

[0022] The shell side inlet of the primary ammonia cooler is connected to the outlet of the ammonia receiving tank, the shell side liquid ammonia outlet of the primary ammonia cooler is connected to the shell side inlet of the secondary ammonia cooler, and the shell side liquid ammonia outlet of the secondary ammonia cooler is connected to the inlet of the gas-ammonia separator;

[0023] The gas ammonia outlets of the primary ammonia cooler and the secondary ammonia cooler are both connected to the inlet of the ammonia compressor;

[0024] The outlet of the ammonia synthesis device is connected to the inlet of the shell side of the secondary ammonia cooler.

[0025] In a possible implementation, the outlet of the ammonia synthesis device is also connected to the inlet of the gas-ammonia separator.

[0026] In a possible implementation, the ammonia refrigeration system further includes a liquid collection bag;

[0027] The inlet of the liquid collecting bag is connected to the gas ammonia outlet of the shell side of the ammonia cooler group, and the outlet of the liquid collecting bag is connected to the inlet of the ammonia compressor.

[0028] In a possible implementation, the liquid holding time of the ammonia cooler group is greater than 2 minutes.

[0029] In a possible implementation, the ammonia booster is a screw ammonia booster.

[0030] In a possible implementation, the ammonia compressor is a centrifugal compressor driven by a high-pressure steam turbine.

[0031] The beneficial effects brought by the technical solution provided by the embodiment of the present application include at least:

[0032] An embodiment of the present application provides an ammonia refrigeration system, which inputs all or part of the liquid ammonia that should be input from the ammonia synthesis device to the gas-ammonia separator into the ammonia cooler group, and converts a part of it into gas ammonia in the shell side of the ammonia cooler group. This part of the gas ammonia enters the ammonia receiving tank for circulation after being pressurized by an ammonia compressor.

[0033] In this way, the ammonia entering the ammonia cooler group from the ammonia synthesis unit is pressurized at a higher pressure, which can reduce energy consumption and save energy compared to flashing in the gas-ammonia separator and then pressurizing through an ammonia booster. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0035] Figure 1 is a schematic diagram of an ammonia refrigeration system provided in an embodiment of the present application;

[0036] Figure 2 is a schematic diagram of an ammonia refrigeration system provided in an embodiment of the present application;

[0037] Figure 3is a schematic diagram of an ammonia refrigeration system provided in an embodiment of the present application;

[0038] Figure 4 is a schematic diagram of an ammonia refrigeration system provided in an embodiment of the present application;

[0039] Figure 5 It is a schematic diagram of an ammonia refrigeration system provided in an embodiment of the present application.

[0040] Legend:

[0041] 1. Ammonia receiving tank;

[0042] 2. Ammonia cooler group, 21. Primary ammonia cooler, 22. Secondary ammonia cooler;

[0043] 3. Gas and ammonia separator;

[0044] 4. Liquid ammonia storage tank;

[0045] 5. Ammonia compressor;

[0046] 6. Liquid ammonia storage tank;

[0047] 7. Gas ammonia cooler;

[0048] 8. Ammonia synthesis unit;

[0049] 9. The first control valve;

[0050] 10. Second control valve;

[0051] 11. Liquid collection bag;

[0052] a. The first pipeline, b. The second pipeline. DETAILED DESCRIPTION

[0053] In order to make the objectives, technical solutions and advantages of the present application clearer, the implementation methods of the present application will be further described in detail below with reference to the accompanying drawings.

[0054] Although the synthetic ammonia process has a history of hundreds of years, new designs continue to emerge with the advancement of technology and the gradual increase in people's requirements for energy and environmental protection.

[0055] The synthesis gas leaving the synthesis tower enters the primary ammonia cooler and the secondary ammonia cooler for further cooling after multi-stage cooling, and then enters the ammonia separator. The liquid ammonia that provides cooling for the ammonia cooler comes from the ammonia refrigeration system. That is, the liquid ammonia from the ammonia flash tank is sent to the primary ammonia cooler as a refrigerant through the ammonia receiving tank, and then a stream of liquid ammonia is drawn out from the primary ammonia cooler and enters the secondary ammonia cooler as a refrigerant to cool the process gas. The gaseous ammonia from the secondary ammonia cooler enters the ammonia compressor, and after being pressurized by the compressor, it is mixed with the higher-pressure gaseous ammonia from the primary ammonia cooler and enters the second stage of the ammonia compressor. After cooling, the condensed liquid ammonia at the outlet gas of the second stage of the ammonia compressor is sent to the ammonia receiving tank.

[0056] Under hot ammonia conditions, the ammonia product extracted from the ammonia receiving tank is sent to the urea unit through a hot ammonia pump. When the urea unit is shut down, it enters the cold ammonia condition, and the liquid ammonia product from the ammonia flash tank enters the gas ammonia separation tank for flash evaporation. After flash evaporation, the liquid ammonia with a lower temperature is sent to the ammonia storage tank, and half of the flashed gas ammonia is pressurized by a screw ammonia booster driven by a motor and then cooled and sent back to the ammonia receiving tank.

[0057] Under hot ammonia conditions, all the liquid ammonia in the ammonia refrigeration cycle flashes in the ammonia refrigeration system, and its cooling capacity has been fully utilized. However, under cold ammonia conditions, a large amount of liquid ammonia is directly depressurized to near normal pressure and sent to the ammonia tank area. The flash gas needs to be pressurized from normal pressure by a screw ammonia booster, wasting a lot of energy in the process.

[0058] The present application embodiment provides an ammonia refrigeration system, such as Figure 1 As shown, the ammonia refrigeration system includes an ammonia receiving tank 1, an ammonia cooler group 2, a gas-ammonia separator 3, a liquid ammonia storage tank 4, an ammonia compressor 5, an ammonia booster 6, a gas-ammonia cooler 7 and an ammonia synthesis device 8. The outlet of the ammonia receiving tank 1 is connected to the inlet of the shell side of the ammonia cooler group 2, the liquid ammonia outlet of the shell side of the ammonia cooler group 2 is connected to the inlet of the gas-ammonia separator 3, and the liquid ammonia outlet of the gas-ammonia separator 3 is connected to the liquid ammonia storage tank 4. The gas-ammonia outlet of the shell side of the ammonia cooler group 2 is connected to the inlet of the ammonia compressor 5, the outlet of the ammonia compressor 5 is connected to the inlet of the gas-ammonia cooler 7, the gas-ammonia outlet of the gas-ammonia separator 3 is connected to the inlet of the ammonia booster 6, the outlet of the ammonia booster 6 is connected to the inlet of the gas-ammonia cooler 7, and the outlet of the gas-ammonia cooler 7 is connected to the inlet of the ammonia receiving tank 1. The outlet of the ammonia synthesis device 8 is connected to the inlet of the shell side of the ammonia cooler group 2.

[0059] The ammonia receiving tank 1 is used to store and transport ammonia.

[0060] The ammonia cooler group 2 is used to cool the gas ammonia. The ammonia cooler group 2 includes a shell side and a tube side. The shell side of the ammonia cooler group 2 is used to supply the coolant flow, and the tube side is used to supply the cooled ammonia flow. In a possible implementation, the liquid holding time of the ammonia cooler group 2 is greater than 2 minutes, wherein the liquid holding time refers to the time required for all the existing coolant in the ammonia cooler group 2 to evaporate into gas ammonia when the coolant input to the ammonia cooler group 2 is stopped. The longer the liquid holding time, the larger the volume of the shell side of the ammonia cooler group 2. The pressure in the shell side of the ammonia cooler group 2 is greater than the pressure of the gas ammonia separator 3, and less than the pressure in the ammonia synthesis device 8.

[0061] The gas ammonia separator 3 is used to flash the input high-pressure liquid ammonia. Flashing refers to the phenomenon that after the high-pressure saturated liquid enters the relatively low-pressure container, due to the sudden decrease in pressure, these saturated liquids become saturated steam and saturated liquid under the pressure of a part of the container. The low-pressure liquid ammonia obtained by flashing the gas ammonia separator 3 is input into the liquid ammonia storage tank 4, and the gas ammonia obtained by flashing is input into the ammonia booster 6.

[0062] The liquid ammonia storage tank 4 is used to store liquid ammonia.

[0063] The ammonia compressor 5 is used to increase the pressure of the gaseous ammonia outputted from the ammonia cooler group 2. Exemplarily, the ammonia compressor 5 is a centrifugal compressor driven by a high-pressure steam turbine.

[0064] The ammonia booster 6 is used to boost the pressure of the gaseous ammonia output from the gaseous ammonia separator 3. For example, the ammonia booster 6 may be a screw-type ammonia booster.

[0065] The gas ammonia cooler 7 is used to cool the gas ammonia outputted from the ammonia compressor 5 and the ammonia booster 6, so as to convert the gas ammonia into liquid ammonia, and input the liquid ammonia into the ammonia receiving tank 1 to form a circulation.

[0066] The ammonia synthesis device 8 is used to generate liquid ammonia. The pressure of the liquid ammonia generated by the ammonia synthesis device 8 is relatively high.

[0067] The scheme shown in the embodiment of the present application, the ammonia refrigeration system provided in the embodiment of the present application, inputs all or part of the liquid ammonia that should be input from the ammonia synthesis device 8 to the gas ammonia separator 3 into the ammonia cooler group 2, and a part of it is converted into gas ammonia in the shell side of the ammonia cooler group 2. This part of the gas ammonia is pressurized by the ammonia compressor 5 and enters the ammonia receiving tank 1 for circulation.

[0068] In this way, the ammonia entering the ammonia cooler group 2 from the ammonia synthesis device 8 is pressurized at a higher pressure, which can reduce energy consumption and save energy compared to flash evaporation in the gas-ammonia separator 3 and then pressurized by the ammonia booster 6.

[0069] In a specific implementation, Figure 1 As shown, the outlet of the ammonia synthesis device 8 is also connected to the inlet of the gas-ammonia separator 3 .

[0070] That is, a part of the liquid ammonia coming out of the ammonia synthesis device 8 directly enters the gas-ammonia separator 3, and the other part is introduced into the shell side of the ammonia cooler group 2 as a coolant to cool the ammonia in the tube side of the ammonia cooler group 2, and then enters the gas-ammonia separator 3.

[0071] It should be noted that, due to the addition of a pipeline from the ammonia synthesis device 8 to the inlet of the shell side of the ammonia cooler group 2, the flash volume of the ammonia cooler group 2 increases, and the amount of gaseous ammonia input to the ammonia compressor 5 increases. In order to prevent the gaseous ammonia from carrying liquid ammonia droplets into the ammonia compressor 5 and causing damage to the ammonia compressor 5, in a specific implementation, a liquid collecting bag is provided at the gaseous ammonia outlet of the shell side of the ammonia cooler group 2, and a wire mesh demister is provided in the liquid collecting bag, which can remove liquid ammonia droplets carried by the gaseous ammonia.

[0072] like Figure 3-Figure 5 As shown, the ammonia cooler group 2 provided in the embodiment of the present application includes a primary ammonia cooler 21 and a secondary ammonia cooler 22. The shell side inlet of the primary ammonia cooler 21 is connected to the outlet of the ammonia receiving tank 1, the shell side liquid ammonia outlet of the primary ammonia cooler 21 is connected to the shell side inlet of the secondary ammonia cooler 22, and the shell side liquid ammonia outlet of the secondary ammonia cooler 22 is connected to the inlet of the gas ammonia separator 3. The gas ammonia outlets of the primary ammonia cooler 21 and the secondary ammonia cooler 22 are both connected to the inlet of the ammonia compressor 5.

[0073] The outlet of the ammonia synthesis device 8 recorded in the embodiments of the present application is connected to the inlet of the shell side of the ammonia cooler group 2, which may mean that the outlet of the ammonia synthesis device 8 is respectively connected to the inlet of the shell side of the first-stage ammonia cooler 21 and the inlet of the shell side of the second-stage ammonia cooler 22, or that the outlet of the ammonia synthesis device 8 is connected to the inlet of the shell side of the first-stage ammonia cooler 21, or that the outlet of the ammonia synthesis device 8 is connected to the inlet of the shell side of the second-stage ammonia cooler 22.

[0074] The following describes these three situations respectively:

[0075] (1) Figure 3 As shown, the outlet of the ammonia synthesis device 8 is connected to the inlet of the shell side of the primary ammonia cooler 21 and the inlet of the shell side of the secondary ammonia cooler 22 respectively.

[0076] That is, two pipelines are added to the conventional process flow, and a branch pipeline leading to the shell side inlet of the primary ammonia cooler 21 is added to the pipeline from the ammonia synthesis unit 8 to the gas ammonia separator 3, such as Figure 3 The first pipeline a shown in FIG. 1 and the branch pipeline for adding the inlet to the shell side of the secondary ammonia cooler 22 are as shown in FIG. Figure 3 The second pipeline b is shown in .

[0077] In addition, a first control valve 9 and a second control valve 10 may be provided on the first pipeline a and the second pipeline b, respectively. The first control valve 9 and the second control valve 10 may be manually switched stop valves or ball valves, or may be control valve groups, so that the valve opening may be controlled under different operating conditions.

[0078] In a specific implementation, the first control valve 9 and the second control valve 10 are configured to adjust the opening of the valves based on the liquid level of liquid ammonia in the ammonia synthesis device 8 .

[0079] For example, when the ammonia synthesis unit 8 supplies ammonia to the liquid ammonia storage tank 6, the following control program may be used:

[0080] When the liquid level in the ammonia synthesis device 8 is 0-50%, the first control valve 9 is opened and the valve opening of the first control valve 9 is different corresponding to different liquid levels. For example, when the liquid level is 50%, the first control valve 9 is fully opened, and when the liquid level is 0, the first control valve 9 is closed. Optionally, when the liquid level is 0-50%, the second control valve 10 can be closed.

[0081] When the liquid level in the ammonia synthesis unit 8 is 50%-100%, the first control valve 9 can be fully opened, and the second control valve 10 is also opened, and the valve opening of the second control valve 10 is different corresponding to different liquid levels. For example, when the liquid level is 50%, the second control valve 10 can be closed, and when the liquid level is 100%, the second control valve 10 is fully opened.

[0082] It should be noted that in order to realize automatic control of the first control valve 9 and the second control valve 10 based on the liquid level in the ammonia synthesis device 8. The ammonia refrigeration system also includes a liquid level detector, which is used to detect the liquid level in the ammonia synthesis device 8. The ammonia refrigeration system also includes a controller, which is electrically connected to the liquid level detector, the first control valve 9 and the second control valve 10 respectively, and the first control valve 9 and the second control valve 10 adjust the valve opening under the control of the controller.

[0083] (2) Figure 4 As shown, the outlet of the ammonia synthesis device 8 is connected to the inlet of the shell side of the primary ammonia cooler 21.

[0084] That is, a pipeline is added to the conventional process flow, and a branch pipeline leading to the inlet of the shell side of the primary ammonia cooler 21 is added to the pipeline from the ammonia synthesis unit 8 to the gas ammonia separator 3, such as Figure 4 The first pipeline a shown in .

[0085] In addition, a first control valve 9 may be provided on the first pipeline a. The first control valve 9 may be a manually switched stop valve or a ball valve, or a control valve group, so that the valve opening may be controlled under different operating conditions. Exemplarily, the first control valve 9 is configured to adjust the valve opening based on the liquid level of the liquid ammonia in the ammonia synthesis device 8.

[0086] Next, in combination with specific experimental results, the energy-saving effect of the ammonia refrigeration system provided in the embodiment of the present application is described:

[0087] Under the cold ammonia condition, all the liquid ammonia in the ammonia synthesis unit 8 is discharged into the primary ammonia cooler 21. In this way, the gas processing capacity of the low-pressure cylinder of the ammonia compressor 5 is greatly increased, increasing by 4631.67Nm 3 / h, the gas volume processed by the high-pressure cylinder of the ammonia compressor 5 increased by 6782.79Nm 3 / h, the total power of the ammonia compressor 5 increased by 432.14KW, but the gas volume processed by the ammonia booster 6 decreased by 7088.45Nm 3 / h, the power of ammonia booster 6 is reduced by 1917.18KW, and the total power is reduced by 485.04KW. The data of the traditional process and the improved process can be shown in Table 1 below. The energy-saving effect is very obvious.

[0088] Table 1

[0089] Technical indicators Traditional process Improved process <![CDATA[Flow rate processed by the high-pressure cylinder of the ammonia compressor (Nm 3 / h)]]> 81458.27 88241.06 <![CDATA[The processing flow rate of the low-pressure cylinder of the ammonia compressor (Nm 3 / h)]]> 30566.74 35198.41 <![CDATA[Screw-type ammonia booster gas handling capacity (Nm 3 / h)]]> 13598.51 6510.06 Ammonia compressor high pressure cylinder power (KW) 3673.56 3991.40 Ammonia compressor low pressure cylinder power (KW) 754.35 868.65 Screw ammonia booster power (KW) 1763.57 846.39 The sum of the power of the syngas compressor and the ammonia compressor (KW) 6191.48 5706.44 Compressor power reduction compared to traditional process (KW) - 485.04

[0090] In addition, this process increases the power of the steam-driven compressor and reduces the power of the electric-driven compressor, which further saves energy and is beneficial to the recovery and comprehensive utilization of steam capacity.

[0091] (3) Figure 5 As shown, the outlet of the ammonia synthesis device 8 is connected to the inlet of the shell side of the secondary ammonia cooler 22 .

[0092] That is, a pipeline is added to the conventional process flow, and a branch pipeline leading to the shell side inlet of the secondary ammonia cooler 22 is added to the pipeline from the ammonia synthesis unit 8 to the gas ammonia separator 3, such as Figure 5 The second pipeline b is shown in .

[0093] In addition, a second control valve 10 may be provided on the second pipeline b. The second control valve 10 may be a manually switched stop valve or ball valve, or a control valve group, so that the valve opening can be controlled under different operating conditions. Exemplarily, the second control valve 10 is configured to adjust the valve opening based on the liquid level of liquid ammonia in the ammonia synthesis device 8.

[0094] Next, in combination with specific experimental results, the energy-saving effect of the ammonia refrigeration system provided in the embodiment of the present application is described:

[0095] Under the cold ammonia condition, all the liquid ammonia in the ammonia synthesis unit 8 is discharged into the secondary ammonia cooler 22. In this way, the processing gas volume of the low-pressure cylinder of the ammonia compressor 5 is greatly increased, increasing by 6883Nm 3 / h, the gas volume processed by the high-pressure cylinder of the ammonia compressor 5 increased by 6851.71Nm 3 / h, the total power of the ammonia compressor 5 increased by 426.44KW. However, the gas volume processed by the ammonia booster 6 decreased by 7105.28Nm 3 / h, the power of ammonia booster 6 is reduced by 919.38KW, and the total power is reduced by 492.94KW. The data of the traditional process and the improved process can be shown in Table 2 below, and the energy-saving effect is very obvious.

[0096] Table 2

[0097] Technical indicators Traditional process Improved process <![CDATA[High-pressure cylinder processing flow rate of ammonia compressor (Nm 3 / h)]]> 81458.27 88309.98 <![CDATA[Flow rate handled by the low-pressure cylinder of the ammonia compressor (Nm 3 / h)]]> 30566.74 37449.26 <![CDATA[Screw-type ammonia booster gas handling capacity (Nm 3 / h)]]> 13598.51 6493.23 Ammonia compressor high pressure cylinder power (KW) 3673.56 3931.14 Ammonia compressor low pressure cylinder power (KW) 754.35 923.21 Screw ammonia booster power (KW) 1763.57 844.19 The sum of the power of the syngas compressor and the ammonia compressor (KW) 6191.48 5698.54 Compressor power reduction compared to traditional process (KW) - 492.94

[0098] In addition, this process increases the power of the steam-driven compressor and reduces the power of the electric-driven compressor, which further saves energy and is beneficial to the recovery and comprehensive utilization of steam capacity.

[0099] In the embodiments of the present application, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance. The term "plurality" refers to two or more, unless otherwise clearly defined.

[0100] The above description is only an optional embodiment of the present application and is not intended to limit the present application. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An ammonia refrigeration system, characterized in that: The ammonia refrigeration system comprises an ammonia receiving tank (1), an ammonia cooler group (2), a gas ammonia separator (3), a liquid ammonia storage tank (4), an ammonia compressor (5), an ammonia booster (6), a gas ammonia cooler (7) and an ammonia synthesis device (8); The outlet of the ammonia receiving tank (1) is connected to the inlet of the shell side of the ammonia cooler group (2), the liquid ammonia outlet of the shell side of the ammonia cooler group (2) is connected to the inlet of the gas ammonia separator (3), and the liquid ammonia outlet of the gas ammonia separator (3) is connected to the liquid ammonia storage tank (4); The gas ammonia outlet of the shell side of the ammonia cooler group (2) is connected to the inlet of the ammonia compressor (5), the outlet of the ammonia compressor (5) is connected to the inlet of the gas ammonia cooler (7), the gas ammonia outlet of the gas ammonia separator (3) is connected to the inlet of the ammonia booster (6), the outlet of the ammonia booster (6) is connected to the inlet of the gas ammonia cooler (7), and the outlet of the gas ammonia cooler (7) is connected to the inlet of the ammonia receiving tank (1); wherein the ammonia cooler group (2) includes a primary ammonia cooler ammonia cooler (21) and a secondary ammonia cooler (22); the shell side inlet of the primary ammonia cooler (21) is connected to the outlet of the ammonia receiving tank (1), the shell side liquid ammonia outlet of the primary ammonia cooler (21) is connected to the shell side inlet of the secondary ammonia cooler (22), and the shell side liquid ammonia outlet of the secondary ammonia cooler (22) is connected to the inlet of the gas-ammonia separator (3); the gas-ammonia outlets of the primary ammonia cooler (21) and the secondary ammonia cooler (22) are both connected to the inlet of the ammonia compressor (5); The outlet of the ammonia synthesis device (8) is respectively connected to the inlet of the shell side of the primary ammonia cooler (21) and the inlet of the shell side of the secondary ammonia cooler (22), and a first control valve (9) is provided on the connecting pipeline between the outlet of the ammonia synthesis device (8) and the inlet of the shell side of the primary ammonia cooler (21); a second control valve (10) is provided on the connecting pipeline between the outlet of the ammonia synthesis device (8) and the inlet of the shell side of the secondary ammonia cooler (22), wherein the first control valve (9) and the second control valve (10) are configured to adjust the valve opening based on the liquid level of liquid ammonia in the ammonia synthesis device (8).

2. The ammonia refrigeration system according to claim 1, characterized in that: The ammonia cooler group (2) comprises a primary ammonia cooler (21) and a secondary ammonia cooler (22); The shell side inlet of the primary ammonia cooler (21) is connected to the outlet of the ammonia receiving tank (1), the shell side liquid ammonia outlet of the primary ammonia cooler (21) is connected to the shell side inlet of the secondary ammonia cooler (22), and the shell side liquid ammonia outlet of the secondary ammonia cooler (22) is connected to the inlet of the gas-ammonia separator (3); The gaseous ammonia outlets of the primary ammonia cooler (21) and the secondary ammonia cooler (22) are both connected to the inlet of the ammonia compressor (5); The outlet of the ammonia synthesis device (8) is connected to the inlet of the shell side of the primary ammonia cooler (21).

3. The ammonia refrigeration system according to claim 1, characterized in that: The ammonia cooler group (2) comprises a primary ammonia cooler (21) and a secondary ammonia cooler (22); The shell side inlet of the primary ammonia cooler (21) is connected to the outlet of the ammonia receiving tank (1), the shell side liquid ammonia outlet of the primary ammonia cooler (21) is connected to the shell side inlet of the secondary ammonia cooler (22), and the shell side liquid ammonia outlet of the secondary ammonia cooler (22) is connected to the inlet of the gas-ammonia separator (3); The gaseous ammonia outlets of the primary ammonia cooler (21) and the secondary ammonia cooler (22) are both connected to the inlet of the ammonia compressor (5); The outlet of the ammonia synthesis device (8) is connected to the inlet of the shell side of the secondary ammonia cooler (22).

4. The ammonia refrigeration system according to any one of claims 1 to 3, characterized in that: The outlet of the ammonia synthesis device (8) is also connected to the inlet of the gas-ammonia separator (3).

5. The ammonia refrigeration system according to any one of claims 1 to 3, characterized in that: The ammonia refrigeration system further comprises a liquid collection bag (11); The inlet of the liquid collecting bag (11) is connected to the gas ammonia outlet of the shell side of the ammonia cooler group (2), and the outlet of the liquid collecting bag (11) is connected to the inlet of the ammonia compressor (5).

6. The ammonia refrigeration system according to any one of claims 1 to 3, characterized in that: The liquid holding time of the ammonia cooler group (2) is greater than 2 minutes.

7. The ammonia refrigeration system according to any one of claims 1 to 3, characterized in that: The ammonia booster (6) is a screw-type ammonia booster.

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