Ammonia separation process coupling ammonia refrigeration and ammonia recovery

Abstract

The invention provides an ammonia refrigeration and ammonia recovery coupled ammonia separation process which comprises the following steps: condensing product gas obtained in an ammonia synthesis process through an ammonia cooler, separating ammonia to obtain liquid ammonia, and inputting the liquid ammonia into a liquid ammonia receiving tank; part of liquid ammonia in the liquid ammonia receiving tank serves as a refrigerant to be input into the ammonia cooler to be subjected to heat exchange with product gas to generate gas ammonia, the gas ammonia is input into an ammonia absorption device to be absorbed by a lean working medium, and an ammonia-rich working medium is obtained; after the ammonia-rich working medium is heated by a low-grade heat source, ammonia is separated from an ammonia desorption device, and the ammonia is condensed and then input into the liquid ammonia receiving tank; the other part of liquid ammonia in the liquid ammonia receiving tank is extracted as an ammonia product; wherein the working medium is an ammonia solution containing calcium chloride, sodium thiocyanate and sodium tripolyphosphate. Compared with a traditional condensation method for ammonia separation, one ammonia cooler is omitted, a solvent desorption device does not need to be arranged, ammonia can be separated from the rich working medium only through a low-grade heat source, equipment investment is saved, the technological process is simplified, and energy consumption is remarkably reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of synthetic ammonia, in particular to an ammonia separation process coupled with ammonia refrigeration and ammonia recovery. BACKGROUND

[0002] Ammonia is one of the basic chemical raw materials, which can be used for the production of agricultural chemical fertilizers (nitrogen fertilizer) such as urea and chemical products such as nitric acid; as the most basic and simplest nitrogen-containing raw material in industry, almost all the most upstream of nitrogen-containing compounds are derived from ammonia; ammonia can also be used as a new type of green fuel or hydrogen energy carrier. In view of the wide application value of ammonia, the production process of ammonia has been continuously developed and optimized.

[0003] In industry, ammonia is synthesized by reacting nitrogen and hydrogen at high temperature and high pressure. Since the ammonia content in the product gas after the synthesis reaction is not high, generally only 12% to 22%, it is necessary to separate ammonia (referred to as "ammonia separation") from the product gas (mainly nitrogen, hydrogen and ammonia), and the remaining nitrogen and hydrogen gas is recycled. The existing ammonia separation methods mainly include absorption method and condensation method. Since the absorbent used in the absorption method is water, the circulating gas after ammonia separation will carry water, which will cause the poisoning of the catalyst for ammonia synthesis. Ammonia and water interact very strongly, and a large amount of low-pressure steam needs to be consumed in the separation process, so the ammonia separation process mainly used in large-scale ammonia synthesis industry is the condensation method.

[0004] The condensation method for ammonia separation must fully cool the synthesis gas at high pressure. The existing ammonia synthesis refrigeration station device mainly uses centrifugal compressors or screw compressors, which consume a large amount of power or medium-pressure superheated steam. In addition, the liquid ammonia condensed by the ammonia cooler in the ammonia synthesis device contains a large amount of non-condensable gas, which needs to be gradually flashed for unreacted gas separation. A separate ammonia recovery section is usually required to recover the flashed gas ammonia, so the traditional compressor type refrigeration station device has the technical problems of high equipment investment, large floor area, and consumption of a large amount of high-grade medium-pressure superheated steam. SUMMARY

[0005] In view of the deficiencies in the prior art, the present application discloses an ammonia separation process coupled with ammonia refrigeration and ammonia recovery, which can replace the centrifugal compressor set in the existing condensation method for ammonia separation and eliminate the equipment related to ammonia recovery, and only low-grade heat source is used to realize ammonia refrigeration and ammonia recovery. The equipment occupies a smaller floor area, which can reduce equipment investment and improve economic benefits.

[0006] In order to achieve the above technical purposes, the present application provides an ammonia separation process coupled with ammonia refrigeration and ammonia recovery, which comprises: liquid ammonia is obtained after the product gas obtained in the ammonia synthesis process is condensed by an ammonia cooler and subjected to a separation process, and the liquid ammonia is input into a liquid ammonia receiving tank; the gaseous components separated in the separation process are input into the upstream ammonia synthesis process as synthesis gas.

[0007] The liquid ammonia in the liquid ammonia receiving tank is divided into two parts, one part is input into the ammonia cooler as refrigerant, and after heat exchange with product gas, gaseous ammonia is generated, which is input into the ammonia absorption device and absorbed by lean working medium to obtain rich ammonia working medium; the rich ammonia working medium is heated by low-grade heat source and separated into ammonia in the ammonia desorption device, and the ammonia is condensed and input into the liquid ammonia receiving tank; the lean working medium output from the ammonia desorption device is cooled and returned to the ammonia absorption device;

[0008] Another part of the liquid ammonia in the liquid ammonia receiving tank is taken out as ammonia product;

[0009] The working medium is an ammonia solution containing calcium chloride, sodium thiocyanate and sodium tripolyphosphate.

[0010] The above technical solution provides an ammonia separation process coupled with ammonia refrigeration and ammonia recovery, specifically:

[0011] In one aspect, part of the liquid ammonia in the liquid ammonia receiving tank is input into the ammonia cooler as refrigerant, which is converted into gaseous ammonia after heat exchange with product gas in the ammonia cooler and is input into the ammonia absorption device and absorbed by lean working medium to obtain rich working medium. The present application introduces a special working medium as absorbent, which is an ammonia solution containing calcium chloride, sodium thiocyanate and sodium tripolyphosphate. The rich working medium after absorbing gaseous ammonia can separate ammonia in the ammonia desorption device by heating with low-grade heat source, and the working medium itself has a high boiling point and almost no evaporation, which avoids affecting the quality of ammonia product and simplifies the operation difficulty of the present application without setting up a solvent desorption process. In the above technical solution, the gaseous ammonia separated from the ammonia desorption device is condensed into liquid ammonia and transported to the liquid ammonia receiving tank; the lean working medium output from the ammonia desorption device is cooled and returned to the ammonia absorption device to absorb the gaseous ammonia output from the ammonia cooler, thereby forming an absorption refrigeration process route for providing cold energy for product synthesis gas and recovering ammonia in liquid ammonia flash gas.

[0012] On the other hand, the ammonia in the product gas (containing nitrogen, hydrogen and ammonia) generated in the upstream ammonia synthesis process is condensed into liquid ammonia in the ammonia cooler, and the unreacted nitrogen and hydrogen (gas phase components) are recovered and returned to the upstream ammonia synthesis process through the ammonia separation process, thereby realizing the recovery of raw material gas; the liquid ammonia obtained by refrigeration in the ammonia cooler is finally input into the liquid ammonia receiving tank. Part of the liquid ammonia in the liquid ammonia receiving tank is input into the subsequent process as liquid ammonia product, and the other part is input into the ammonia cooler as refrigerant, thereby realizing the overall ammonia synthesis and separation process route from the ammonia synthesis process to the output of ammonia product.

[0013] Compared with the technical solution of setting two ammonia coolers in the traditional ammonia synthesis process, the present application simplifies the ammonia cooler to one, significantly reducing the equipment investment of the ammonia synthesis device and simplifying the process flow.

[0014] In addition, the technical scheme adopts low-grade heat sources such as low-pressure steam, hot water and low-position heat as the heat source for desorbing ammonia in the rich working medium, so that the low-grade heat which is difficult to utilize is fully utilized, and the energy utilization efficiency of the whole synthetic ammonia process is improved.

[0015] In further examples of the present application, the composition of the working medium is optimized. Based on a large amount of experimental data, the research and development team of the present application found that the mass ratio of calcium chloride, sodium thiocyanate and sodium tripolyphosphate in the working medium can be selected as (0.5-5):(10-80):(5-30), and further selected as (0.5-5):(10-80):(5-30), thereby achieving the technical effect of efficient absorption and desorption of ammonia in the lean working medium and the rich working medium in the process.

[0016] Compared with the prior art, the present application has the following beneficial effects: the present application uses liquid ammonia as the refrigerant to condense the product gas from the upstream synthetic ammonia process, and uses a special lean working medium to absorb the gas ammonia generated by heat exchange, and then uses a low-grade heat source to heat to promote the rich working medium to precipitate gas ammonia. The gas ammonia is condensed and input into the liquid ammonia tank together with the liquid ammonia condensed from the product gas. Part of the liquid ammonia in the liquid ammonia tank is used as the refrigerant, and another part of the liquid ammonia is used as the ammonia product and input into the downstream process. An ammonia separation process is formed by coupling ammonia refrigeration and ammonia recovery. The ammonia separation process of the present application eliminates one ammonia cooler compared with the traditional condensation method and does not need to set a solvent desorption device. The ammonia and the rich working medium are separated only by using a low-grade heat source. The present application not only saves equipment investment and simplifies the process, but also significantly reduces energy consumption. BRIEF DESCRIPTION OF DRAWINGS

[0017] The drawings accompanying the specification of this application form a part thereof, serve to provide further understanding of the present application, and together with the description of the exemplary embodiments of the present application and their description serve to explain the present application, and do not constitute improper limitations on the present application. In the drawings:

[0018] Figure 1 A structural diagram showing the ammonia synthesis process flow of the present application.

[0019] In the above drawings, the following reference signs are included:

[0020] 11-high-pressure ammonia separation device, 12-medium-pressure ammonia separation device, 2-liquid ammonia tank, 3-ammonia absorption device, 4-ammonia desorption device, 51-ammonia cooler, 52-first heat exchanger, 53-second heat exchanger, 54-third heat exchanger, 55-fourth heat exchanger, 56-fifth heat exchanger. DETAILED DESCRIPTION

[0021] For the purpose of facilitating the understanding of the present application, a more comprehensive description of the present application will be given below, and the preferred embodiments of the present application are given. However, it should be understood that these embodiments are only for the purpose of more detailed description, and should not be understood as limiting the present application in any form, i.e. not intended to limit the protection scope of the present application.

[0022] Embodiment 1

[0023] The present application proposes an ammonia separation process coupled with ammonia refrigeration and ammonia recovery, as shown in the figure, the process comprises: the product gas obtained by the synthetic ammonia process is condensed by the ammonia cooler and liquid ammonia is obtained after the ammonia separation process, the liquid ammonia is input into the liquid ammonia receiving tank; the gaseous phase components separated by the ammonia separation process are input into the upstream synthetic ammonia process as synthesis gas; Figure 1

[0024] The liquid ammonia in the liquid ammonia receiving tank is divided into two parts, one part is input into the ammonia cooler as refrigerant after heat exchange with the product gas to generate gaseous ammonia, the gaseous ammonia is absorbed by the lean working medium in the ammonia absorption device to obtain rich working medium; the rich working medium is heated by low-grade heat source and then separated into ammonia in the ammonia desorption device, the ammonia is condensed and then input into the liquid ammonia receiving tank; the lean working medium output from the ammonia desorption device is cooled and then returned to the ammonia absorption device;

[0025] The other part of the liquid ammonia in the liquid ammonia receiving tank is extracted as ammonia product.

[0026] Among them, the working medium is an ammonia solution including calcium chloride, sodium thiocyanate and sodium tripolyphosphate.

[0027] In the above technical solution, the liquid ammonia as refrigerant is output from the liquid ammonia receiving tank, and is gasified into gaseous ammonia in the ammonia cooler through heat exchange with the product gas, this part of gaseous ammonia is absorbed by the lean working medium in the ammonia absorption device to obtain rich working medium, the rich working medium is heated by low-grade heat source to separate out gaseous ammonia, the gaseous ammonia is condensed to obtain liquid ammonia and is input into the liquid ammonia receiving tank, thereby forming an ammonia separation process route for providing cold energy for the product gas and recovering ammonia in the liquid ammonia.

[0028] Optionally, the mass ratio of calcium chloride, sodium thiocyanate and sodium tripolyphosphate in the working medium is (0.5-5):(10-80):(5-30), and further optionally (2-4):(68-78):(18-30), thereby realizing the technical effects of absorbing and concentrating gaseous ammonia by the lean working medium, and separating out gaseous ammonia from the rich working medium under the action of low-grade heat source.

[0029] Optionally, the temperature of the ammonia absorption device is -15-40℃, and the pressure is 0.10-0.2MPaG, under which conditions, the purpose of efficiently separating and absorbing ammonia in the product gas can be realized.

[0030] Optionally, the non-condensable gas not absorbed in the ammonia absorption device is discharged from the boundary area, and this part of non-condensable gas can be selected as fuel.​

[0031] It should be noted that the present application does not limit the specific structure of the ammonia absorption device, and those skilled in the art can set components for promoting the mass transfer of lean working medium and product gas in the ammonia absorption device through non-creative labor, such as trays, fillers, flow guides, gas distributors or spraying devices, etc., but not limited to the types exemplified, and the technical solutions formed thereby are within the scope of protection of the present application.

[0032] It should be noted that the low-grade heat source in the present application refers to a heat source with a relatively low temperature that is not convenient for direct utilization, such as low-temperature light heat, geothermal heat, low-pressure steam, hot water, low-grade heat process medium with low quality in a chemical industrial park, etc. Alternatively, the temperature range of the low-grade heat source is 80-200°C. In the actual process, the rich working medium can be heat-exchanged with the low-grade heat source in the first heat exchanger, and then ammonia separation is carried out in the desorption device.

[0033] It should be noted that the ammonia desorption device is used for flash separation of the rich working medium heated by the low-grade heat source, to discharge the gaseous ammonia in the rich working medium, and obtain the lean working medium. The gaseous ammonia is condensed into liquid ammonia by the second heat exchanger, and is input into the liquid ammonia tank.

[0034] Alternatively, the pressure of the ammonia desorption device is 0.1-5 MPaG, and the temperature is 60-200°C, which is beneficial to efficient desorption of ammonia product from the rich working medium under the temperature and pressure conditions.

[0035] It should be noted that the present application does not limit the specific structure of the ammonia desorption device, and those skilled in the art can select appropriate equipment for desorbing ammonia according to the needs. Alternatively, the ammonia desorption device is in the form of a flash tank or a desorption tower; further alternatively, when the desorption device is in the form of a desorption tower, the operating pressure is 0.1-5 MPaG.

[0036] Alternatively, the lean working medium is cooled after heat exchange with the gaseous ammonia output by the ammonia cooler, and is then input into the ammonia absorption device. In the actual process, the product gas containing gaseous ammonia is condensed into liquid ammonia after heat exchange with the refrigerant, but the raw material gas (including hydrogen and nitrogen) is still in a gaseous state, so that the gaseous ammonia generated by the refrigerant still retains a certain amount of cold energy. By heat-exchanging the gaseous ammonia with the lean working medium in the fourth heat exchanger, the energy configuration can be further optimized to improve the efficiency of ammonia absorption by the lean working medium in the ammonia absorption device. Further alternatively, the lean working medium is cooled by at least a fifth heat exchanger, so as to control the temperature of the lean working medium input into the ammonia absorption device, and improve the ammonia absorption effect.

[0037] Optionally, the temperature of the lean working medium returned to the ammonia absorption device is 20-40℃, and the temperature of the lean working medium does not need to be reduced to -5-15℃ by a low-temperature heat exchanger, so that the lean working medium can be returned to the ammonia absorption device to absorb gaseous ammonia, thereby reducing the overall process energy consumption.

[0038] Optionally, the temperature of the gaseous ammonia input into the ammonia absorption device is -15-40℃, and the pressure is 0.13-0.2 MPaG. After the refrigerant is vaporized by heat exchange with the product gas in the ammonia cooler, the temperature thereof is about -15℃. In the process of inputting the gaseous ammonia into the ammonia absorption device, heat exchange with other materials in the process can be performed to improve the energy utilization efficiency, so that the temperature of the gaseous ammonia before input into the ammonia absorption device can be -15-40℃.

[0039] It should be noted that the liquid ammonia receiving tank is used to store liquid ammonia, and the structure of the liquid ammonia receiving tank is not limited, and a person skilled in the art can select a liquid ammonia receiving tank with a suitable structure according to actual needs. Optionally, a person skilled in the art can monitor the liquid level in the liquid ammonia receiving tank by arranging a liquid level meter at a suitable position of the liquid ammonia receiving tank.

[0040] Optionally, the flash gas of the liquid ammonia receiving tank is input into the ammonia absorption device, so that the ammonia gas in the liquid ammonia receiving tank is recovered, and the yield of the overall ammonia separation process is improved.

[0041] In the above technical solution, the product gas from the upstream synthetic ammonia process is condensed in the ammonia cooler by the refrigerant to obtain liquid ammonia and unreacted raw material gas (including hydrogen and nitrogen), and the raw material gas is discharged in the ammonia separation and input into the upstream synthetic ammonia process as synthesis gas, and the obtained liquid ammonia is input into the liquid ammonia receiving tank. Part of the liquid ammonia in the liquid ammonia receiving tank is input into the ammonia cooler as the refrigerant, and another part is input into the downstream process after the ammonia product is produced. Thus, an ammonia synthesis process route from the synthetic ammonia process to the output of the ammonia product is formed.

[0042] It should be noted that the ammonia separation process is used to separate the liquid ammonia from the product gas after being condensed in the ammonia cooler and the raw material gas (gas phase component) so as to recover the raw material gas (synthesis gas) and input the liquid ammonia into the liquid ammonia receiving tank.

[0043] Optionally, the ammonia separation process includes a high-pressure ammonia separation process and a medium-pressure ammonia separation process. The high-pressure ammonia separation process is performed in a high-pressure ammonia separation device, and the control pressure is 3.5-6.0 MPaG. The medium-pressure ammonia separation process is performed in a medium-pressure ammonia separation device, and the control pressure is 1.0-2.5 MPaG, so that the liquid ammonia is separated from the raw material gas by stepwise pressure reduction and flash evaporation. It should be noted that the specific structure of the high-pressure ammonia separation device and the medium-pressure ammonia separation device is not limited, and a suitable structure of the ammonia separation device can be selected according to actual needs to achieve the purpose of pressure reduction and flash evaporation.

[0044] It should be noted that in the actual process, the raw gas can be input into different processing stages of the upstream synthesis gas according to the pressure and temperature of the raw gas separated at different stages of the ammonia separation process, such as inputting the gas phase component output by the high-pressure ammonia separation device into the compressed synthesis gas, mixing the gas phase component output by the medium-pressure ammonia separation device with the fresh input synthesis gas, and the like, which does not limit the protection scope of the present application, and those skilled in the art can select and set according to the actual situation.

[0045] Optionally, the gas phase component obtained by the ammonia separation process is input into the upstream ammonia synthesis process after heat exchange with the product gas. In the actual process, the raw gas (gas phase component) obtained by the ammonia separation process can be optionally heat-exchanged with the product gas, so as to recover and utilize the cold energy contained in the raw gas, and improve the overall process energy utilization efficiency. For example, as shown in Figure 1 The raw gas output by the high-pressure ammonia separation device is heat-exchanged with the third heat exchanger and then input into the upstream ammonia synthesis process. Those skilled in the art can select and set according to the actual situation, which does not limit the protection scope of the present application.

[0046] It should be noted that the present application is not limited to the ratio of the liquid ammonia in the liquid ammonia receiving tank as the refrigerant to the liquid ammonia as the ammonia product. The heat exchange process in the process of the present application includes using part of the liquid ammonia in the liquid ammonia receiving tank as the refrigerant for condensing ammonia in the product gas, and using a low-grade heat source for heating to desorb ammonia in the rich working medium, and the like. Those skilled in the art can set the ratio of the liquid ammonia in the liquid ammonia receiving tank as the refrigerant and as the ammonia product according to the need, and monitor the liquid level in the liquid ammonia receiving tank, so as to further reduce the energy consumption in the overall process through the cooperation of heat exchange.

[0047] In order to further verify the technical effect of the technical scheme of the present application, the process of the ammonia separation process coupled with ammonia refrigeration and ammonia recovery under specific working conditions is shown by Examples 2-4. It should be noted that the process is only a display of a relatively optimal flow, and does not limit the protection scope of the present application.

[0048] Example 2

[0049] An ammonia separation process coupled with ammonia refrigeration and ammonia recovery, specifically, the product gas obtained from the upstream ammonia synthesis process is condensed by an ammonia cooler and then liquid ammonia is obtained after an ammonia separation process, and the liquid ammonia is input into a liquid ammonia receiving tank; the gas phase component separated by the ammonia separation process is input into the upstream ammonia synthesis process as synthesis gas. The ammonia separation process includes a high-pressure ammonia separation process (pressure is about 3.5 MPaG) and a medium-pressure ammonia separation process (pressure is about 1.5 MPaG).

[0050] A portion of liquid ammonia output from the liquid ammonia receiving tank is input into the ammonia cooler as a refrigerant to exchange heat with product gas to generate gaseous ammonia, which is input into the ammonia absorption device to be absorbed by the lean working medium to obtain a rich ammonia working medium. In addition, the flash evaporator of the liquid ammonia receiving tank is also input into the ammonia absorption device. Unabsorbed non-condensable gas in the ammonia absorption device is discharged from the system.

[0051] The temperature of the ammonia absorption device is 20°C, the pressure is 0.1 MPaG, and the mass ratio of calcium chloride, sodium thiocyanate and sodium tripolyphosphate in the working medium is 3:73:24. The gaseous ammonia includes H2: 0.03 mol%, N2: 0.02 mol%, and NH3: 99.94 mol%, and the temperature is -10 to -15°C, and the pressure is 0.13 to 0.2 MPaG. The flash gas includes H2: 55.55 mol%, N2: 24.08 mol%, and NH3: 11.68 mol%, and the temperature is about 20°C, and the pressure is 1.5 MPaG. The non-condensable gas includes H2: 63.22 mol%, N2: 26.53 mol%, and NH3: 200 ppm, and the temperature is about 30°C, and the pressure is about 0.1 MPaG.

[0052] The rich working medium is heated by high-temperature hot water waste heat and then input into the ammonia desorption device to separate ammonia, and the ammonia desorption temperature is 155°C. The lean working medium obtained by heat exchange through the fifth heat exchanger and the fourth heat exchanger has a temperature of about 30°C, and is input into the ammonia absorption device to absorb gaseous ammonia. Ammonia products are extracted from the liquid ammonia receiving tank.

[0053] Example 3

[0054] This example has the same process flow as shown in Example 2, except that the mass ratio of calcium chloride, sodium thiocyanate and sodium tripolyphosphate in the working medium used in this example is 2:68:30, and the working medium has the functions of absorbing ammonia at about 40°C in the ammonia absorption device and desorbing ammonia at about 160°C in the ammonia desorption device. The ammonia content in the non-condensable gas extracted from the ammonia absorption device in this example is 50 ppm.

[0055] Example 4

[0056] This example has the same process flow as shown in Example 2, except that the mass ratio of calcium chloride, sodium thiocyanate and sodium tripolyphosphate in the working medium used in this example is 2:68:30, and the working medium has the functions of absorbing ammonia at about 40°C in the ammonia absorption device and desorbing ammonia at about 160°C in the ammonia desorption device. The ammonia content in the non-condensable gas extracted from the ammonia absorption device in this example is 50 ppm.

[0057] It should be noted that the above is a further detailed description of the present application in combination with specific embodiments, and the specific implementation of the present application cannot be limited to these descriptions; the size data of the embodiments does not limit the technical solutions, but only shows one specific working condition. For those skilled in the art to which the present application belongs, without departing from the concept of the present application, a number of simple improvements and refinements can be made, which should be considered as falling within the scope of the present application.

Claims

1. An ammonia separation process coupling ammonia refrigeration and ammonia recovery, characterized in that, The product gas obtained from the ammonia synthesis process is condensed by an ammonia cooler and then subjected to an ammonia separation process to obtain liquid ammonia, which is then fed into a liquid ammonia receiving tank; the gas phase components separated in the ammonia separation process are used as synthesis gas and fed into the upstream ammonia synthesis process. The liquid ammonia in the liquid ammonia receiving tank is divided into two parts. One part is used as a refrigerant and is fed into the ammonia cooler to exchange heat with the product gas to generate gaseous ammonia. The gaseous ammonia is fed into the ammonia absorption device and absorbed by the lean working fluid to obtain the ammonia-rich working fluid. The ammonia-rich working fluid is heated by a low-grade heat source and then separated into ammonia in the ammonia desorption device. The ammonia is condensed and fed into the liquid ammonia receiving tank. The lean working fluid output from the ammonia desorption unit is cooled and returned to the ammonia absorption unit; Another portion of the liquid ammonia in the liquid ammonia receiving tank is extracted as ammonia product. The working medium is an ammonia solution comprising calcium chloride, sodium thiocyanate, and sodium tripolyphosphate.

2. The ammonia separation process coupled with ammonia refrigeration and ammonia recovery according to claim 1, characterized in that, The mass ratio of calcium chloride, sodium thiocyanate, and sodium tripolyphosphate in the working medium is (0.5-5):(10-80):(5-30); preferably (2-4):(68-78):(18-30).

3. The ammonia separation process coupled with ammonia refrigeration and ammonia recovery according to claim 1, characterized in that, The temperature of the ammonia absorption device is -15 to 40°C, and the pressure is 0.10 to 0.2 MPaG.

4. The ammonia separation process coupled with ammonia refrigeration and ammonia recovery according to claim 1, characterized in that, Unabsorbed non-condensable gases from the ammonia absorption device are discharged from the boundary area.

5. The ammonia separation process coupled with ammonia refrigeration and ammonia recovery according to claim 1, characterized in that, The pressure of the ammonia desorption device is 0.1 MPaG to 5 MPaG, and the temperature is 60 to 200℃.

6. The ammonia separation process coupled with ammonia refrigeration and ammonia recovery according to claim 1, characterized in that, The ammonia desorption device is either a flash tank type or a desorption tower type.

7. The ammonia separation process coupled with ammonia refrigeration and ammonia recovery according to claim 1, characterized in that, The lean working fluid exchanges heat with the gaseous ammonia output from the ammonia cooler, is cooled, and then input into the ammonia absorption device. And / or, the temperature of the lean working fluid returned to the ammonia absorption device is 20–40°C.

8. The ammonia separation process coupled with ammonia refrigeration and ammonia recovery according to claim 1, characterized in that, The temperature of the gaseous ammonia input to the ammonia absorption device is -15 to 40°C, and the pressure is 0.13 to 0.2 MPaG.

9. The ammonia separation process coupled with ammonia refrigeration and ammonia recovery according to claim 1, characterized in that, It also includes feeding the flash vapor from the liquid ammonia receiving tank into the ammonia absorption device.

10. The ammonia separation process coupled with ammonia refrigeration and ammonia recovery according to claim 1, characterized in that, The ammonia separation process includes a high-pressure ammonia separation process and a medium-pressure ammonia separation process; And / or, the gaseous components obtained from the ammonia separation process are heat-exchanged with the product gas before being input into the upstream ammonia synthesis process.

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