Liquid ammonia and ammonia water co-production device and method

Abstract

The invention provides a liquid ammonia and ammonia water co-production device and method, and belongs to the technical field of ammonia production. The liquid ammonia and ammonia water co-production device comprises a cooler E3, an ammonia cooler E4, an ammonia separator S1 and an ammonia washing tower T3, wherein the yield ratio of the liquid ammonia to the ammonia water can be adjusted by adjusting the ammonia cooling temperature and / or the evaporation liquid level height in the ammonia cooler E4. According to the method, after ammonia synthesis gas is sequentially subjected to two-stage cooling, a liquid phase separated by an ammonia separator S1 is liquid ammonia, and a gas phase is in contact with water in an ammonia washing tower T3 to form ammonia water. According to the invention, ammonia water can be obtained in the ammonia washing tower T3 while liquid ammonia is obtained in the ammonia separator S1, and a large amount of corresponding equipment does not need to be added; and according to requirements, the temperature of the gas after ammonia cooling can be controlled by controlling the ammonia cooling temperature of the ammonia cooler E4 and / or the evaporation liquid level height of the ammonia cooler E4, so that the purpose of timely distributing and adjusting the yield ratio of the liquid ammonia to the ammonia water is achieved, namely, the ratio of the liquid ammonia to the ammonia water can be adjusted.

Description

Technical Field

[0001] The present invention relates to the technical field of ammonia production, and in particular to a device and method for co-producing liquid ammonia and ammonia water. Background Art

[0002] Industrial ammonia water is an emerging environmentally friendly product for flue gas desulfurization and denitrification in recent years. Liquid ammonia is the film-forming gas for nitride films in the electronics industry, an important "nitrogen" source for chemical vapor deposition (CVD), and a very important raw material in the electronics field with huge development potential.

[0003] The Chinese invention (name: "A system and process for the co-production of industrial ammonia water and high-purity ammonia", announcement number: CN110510636B, announcement date: 20240416) discloses a system and process for the co-production of industrial ammonia water and high-purity ammonia, which belongs to the technical field of industrial ammonia production. The co-production system includes an industrial ammonia water and high-purity ammonia production system, a waste ammonia treatment system and a water circulation system; the industrial ammonia water and high-purity ammonia production system includes a liquid ammonia storage tank and a liquid ammonia absorber, the liquid ammonia storage tank is connected to the ammonia gasifier, the regeneration heater, the purifier, the distillation tower and the high-purity ammonia finished product tank in sequence, and the liquid ammonia absorber is connected to the ammonia water finished product tank, which can realize the production capacity regulation of high-purity ammonia and industrial ammonia water. The waste ammonia treatment system includes a waste ammonia main pipe, which is respectively connected to the liquid ammonia storage tank, the purifier, the distillation tower and the high-purity ammonia finished product tank, and the waste ammonia main pipe is connected to the liquid ammonia absorber, and the waste gas in the waste gas main pipe can be directly used to produce industrial ammonia water, ensuring that the regenerated ammonia will not be wasted. The water circulation system includes a high-temperature water main, a low-temperature water main and an industrial water softening device, which can realize the comprehensive utilization of heat.

[0004] However, in the above technical solution, industrial ammonia water needs to first complete the preparation of liquid ammonia, then gasify the liquid ammonia to form ammonia gas, and finally the ammonia gas is contacted and mixed with industrial water to produce ammonia water. The overall process flow is relatively long and more corresponding equipment is required. Summary of the invention

[0005] The present invention aims to provide a device and method for the co-production of liquid ammonia and ammonia water, which can obtain liquid ammonia in an ammonia separator S1 and ammonia water in an ammonia washing tower T3 at the same time, without adding a large number of corresponding equipment; and according to demand, the temperature of the ammonia-cooled gas can be controlled by controlling the ammonia cooling temperature of the ammonia cooler E4 and / or the evaporation liquid level height of the ammonia cooler E4, so as to achieve the purpose of timely distribution and adjustment of the output ratio of liquid ammonia and ammonia water, that is, the ratio of liquid ammonia to ammonia water can be adjusted.

[0006] The technical solution adopted by the present invention is: A device for co-producing liquid ammonia and ammonia water, comprising: A cooler E3, wherein the cooler E3 is used to cool the ammonia synthesis gas; an ammonia cooler E4, the ammonia cooler E4 being connected to the cooler E3 to further cool the ammonia synthesis gas; an ammonia separator S1, the ammonia separator S1 being connected to the ammonia cooler E4, for performing gas-liquid separation on the ammonia synthesis gas after cooling; An ammonia washing tower T3, the lower part of which is connected to the top of the ammonia separator S1; the upper part of which is also connected to water; The liquid phase separated at the bottom of the ammonia separator S1 is liquid ammonia; the gas phase separated at the top of the ammonia separator S1 flows from bottom to top after entering the ammonia washing tower T3, and contacts with water flowing from top to bottom in the ammonia washing tower T3, and the ammonia in the gas phase is absorbed by the water; the liquid phase at the bottom of the ammonia washing tower T3 is aqueous ammonia; the production ratio of liquid ammonia to aqueous ammonia can be adjusted by adjusting the ammonia cooling temperature and / or the evaporation liquid level in the ammonia cooler E4.

[0007] Furthermore, the liquid ammonia at the bottom of the ammonia separator S1 is sent to the downstream equipment through the control valve V1.

[0008] Furthermore, the ammonia water at the bottom of the ammonia washing tower S1 is sent to the downstream equipment through the control valve V2.

[0009] Furthermore, it also includes: A deoxygenation tower T1, wherein the deoxygenation tower T1 is used to deoxygenate the raw gas; wherein the raw gas includes hydrogen and nitrogen; A deoxygenation cooler E1, which is connected to the bottom of the deoxygenation tower T1 and is used to cool the raw gas after deoxygenation in the deoxygenation tower T1; A drying system PK1, the top of which is connected to the deoxygenation cooler E1, for drying and dehydrating the raw gas after being cooled by the deoxygenation cooler E1; A circulating gas compressor C2, which is connected to the bottom of the drying system PK1 and is used to re-compress the raw gas after drying and dehydration by the drying system PK1; Ammonia synthesis tower T2, the top of the ammonia synthesis tower T2 is connected to the circulating gas compressor C2, so as to convert the raw gas compressed again by the circulating gas compressor C2 into ammonia synthesis gas, and discharge it from the bottom of the ammonia synthesis tower T2 to the cooler E3.

[0010] Furthermore, it also includes: The raw gas compressor C1 is connected to the top of the deoxidation tower T1 and is used to compress the raw gas to the pressure required for ammonia synthesis through the raw gas compressor C1 and then send it to the deoxidation tower T1.

[0011] Furthermore, the drying system PK1 has one or more drying towers.

[0012] Furthermore, it also includes: The heat exchanger E2 is located between the circulating gas compressor C2 and the ammonia synthesis tower T2; wherein the heat exchanger E2 uses the ammonia synthesis gas discharged from the bottom of the ammonia synthesis tower T2 as a heat source, and exchanges heat with the raw gas compressed again by the circulating gas compressor C2.

[0013] Furthermore, the top of the ammonia washing tower T3 is connected to the top of the drying system PK1.

[0014] Furthermore, a cyclone separator is arranged in the tank body of the ammonia separator S1; and a wire mesh demister is also arranged at the top outlet of the tank body.

[0015] Based on the same inventive concept, the present invention also provides a method for co-producing liquid ammonia and ammonia water, which is implemented based on the aforementioned liquid ammonia and ammonia water co-production device. After the ammonia synthesis gas is cooled in two stages, namely, the cooler E3 and the ammonia cooler E4, the ammonia separator S1 is used to separate the gas and liquid; the liquid phase separated by the ammonia separator S1 is liquid ammonia; the gas phase separated by the ammonia separator S1 contacts with water in the ammonia washing tower T3 to form ammonia water.

[0016] The beneficial effects of the present invention are: 1. While obtaining liquid ammonia in the ammonia separator S1, ammonia water can also be obtained in the ammonia washing tower T3, that is, two products are produced in one process without the need for a large number of new corresponding equipment.

[0017] 2. According to demand, the temperature of the gas after ammonia cooling can be controlled by controlling the ammonia cooling temperature of the ammonia cooler E4 and / or the evaporation liquid level of the ammonia cooler E4, so as to achieve the purpose of timely distribution and adjustment of the production ratio of liquid ammonia and ammonia water, that is, the ratio of liquid ammonia to ammonia water can be adjusted.

[0018] 3. Drying system PK1 can remove water carried in the raw gas and water generated by the deoxygenation reaction, and can also remove water in the circulating gas after water washing in the ammonia washing tower T3.

[0019] 4. In this embodiment, the flow control valve V3 of the water wash at the top of the ammonia washing tower T3 can be controlled to control the water flow rate, so as to flexibly control the ammonia concentration after the ammonia absorption at the bottom of the tower.

[0020] 5. Since the circulating gas has been washed and deammonified by the ammonia washing tower T3, the ammonia content in the mixture of the raw gas and the circulating gas entering the ammonia synthesis tower T2 is very low, the ammonia net value of the ammonia synthesis tower T2 is higher, the ammonia synthesis efficiency is improved, and the power of the circulating gas compressor C2 is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art 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 paying creative work.

[0022] Figure 1 Schematic diagram of the process connection structure of the liquid ammonia and ammonia water co-production device in Example 1.

[0023] Figure 2 Schematic diagram of the structure of the ammonia separator S1 in Example 1.

[0024] The accompanying drawings are marked as follows: 100-tank body, 200-cyclone separator, 300-wire mesh demister. DETAILED DESCRIPTION

[0025] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0026] The disclosure below provides many different embodiments or examples to realize different structures of the present invention. In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention.

[0027] The embodiments of the invention are described in detail below with reference to the accompanying drawings.

[0028] Example 1

[0029] Figure 1 Schematic diagram of the process connection structure of the liquid ammonia and ammonia water co-production device in Example 1. Figure 1 As shown in , the liquid ammonia and ammonia water co-production device includes a raw gas compressor C1. The raw gas required for ammonia synthesis is mixed according to the required ratio and enters the raw gas compressor C1, and the raw gas compressor C1 compresses the raw gas to the pressure required for ammonia synthesis (5~30MPa). The raw gas includes hydrogen and nitrogen.

[0030] Since the raw gas contains a small amount of oxygen in addition to hydrogen and nitrogen, and oxygen will affect ammonia synthesis, the compressed raw gas needs to be deoxygenated. The compressed raw gas output by the raw gas compressor C1 enters the deoxygenation tower T1 from the top of the deoxygenation tower T1, flows from top to bottom and contacts with the packing loaded with deoxidizer in the deoxygenation tower T1 to achieve deoxygenation, and is finally discharged from the bottom of the deoxygenation tower T1.

[0031] As the deoxygenation reaction continues, the temperature of the raw gas will gradually increase, so the deoxygenated raw gas discharged from the bottom of the deoxygenation tower T1 is cooled by the deoxygenation cooler E1.

[0032] Since the raw gas itself carries some water, and the raw gas also produces water during the deoxygenation reaction, the raw gas cooled by the deoxygenation cooler E1 enters the drying system PK1 from the top of the drying system PK1, and then is discharged from the bottom of the drying system PK1 to achieve drying and dehydration. The drying system PK1 has one or more drying towers to improve the drying efficiency.

[0033] The dried and dehydrated raw gas enters the circulating gas compressor C2, and is compressed again by the circulating gas compressor C2 to the pressure required for ammonia synthesis. The compressed raw gas enters the heat exchanger E2 to preheat the raw gas, and the preheated raw gas enters the ammonia synthesis tower T2 from the top of the ammonia synthesis tower T2 to undergo an ammonia synthesis reaction, generate ammonia synthesis gas, and is discharged from the bottom of the ammonia synthesis tower T2. At the same time, the ammonia synthesis gas is used as a heat source in the heat exchanger E2 to exchange heat with the relatively low-temperature raw gas, thereby increasing the temperature of the raw gas and reducing the temperature of the ammonia synthesis gas.

[0034] After heat exchange with the feed gas in the heat exchanger E2, the ammonia synthesis gas enters the cooler E3 for further cooling, and then is further cooled to a preset low temperature (e.g., -34°C under standard atmospheric pressure) in the ammonia cooler E4, and finally sent to the middle and lower part of the ammonia separator S1 for gas-liquid separation. Among them, the ammonia cooling temperature and the evaporation liquid level of the ammonia cooler E4 can be adjusted, for example, by controlling the flow of the cold source entering the ammonia cooler E4 through a flow control valve, thereby adjusting the ammonia cooling temperature in the ammonia cooler E4; for another example, by adjusting the liquid level control valve to control the amount of ammonia synthesis gas flowing into the ammonia cooler E4, thereby adjusting the evaporation liquid level.

[0035] at the same time, Figure 2It is a schematic diagram of the structure of the ammonia separator S1 in Example 1, in which part of the side wall of the tank body is not shown, so as to facilitate the observation of the internal structure of the tank body. The ammonia separator S1 includes a tank body 100. A cyclone separator 200 is arranged in the lower middle part of the tank body 100, and the axial center of the cyclone separator 200 coincides with the axial center of the tank body 100, and there is a gap between its outer wall and the inner wall of the adjacent tank body 100. The inlet in the tangential direction of the upper part of the cyclone separator 200 extends outside the tank body 100. A wire mesh demister 300 is also arranged at the top outlet of the tank body 100. After further cooling by the ammonia cooler E4, the ammonia synthesis gas (substantially a gas-liquid mixture) enters the cyclone separator 200 along the tangential direction of the upper part of the cyclone separator 200. Under the action of centrifugal force and gravity, the liquid phase is discharged from the bottom outlet of the cyclone separator 200 and flows into the bottom of the tank body 100, and the gas phase is discharged from the top outlet of the cyclone separator 200, and finally flows through the wire mesh demister 300 for defoaming and is discharged from the top of the tank body 100. The liquid phase separated in the ammonia separator S1 is liquid ammonia, which is discharged from the bottom of the ammonia separator S1 and sent to the downstream equipment through the control valve V1.

[0036] The gas phase separated in the ammonia separator S1 is discharged from the top of the ammonia separator S1 and sent to the lower part of the ammonia washing tower T3, flowing from bottom to top and contacting with the water added from the upper part of the ammonia washing tower T3 flowing from top to bottom. The ammonia in the gas phase is absorbed by the water, and the remaining gas phase, i.e., the circulating gas, is discharged from the top of the ammonia washing tower T3 and mixed with the raw gas cooled by the cooler E1 and sent to the drying system PK1. Among them, the flow rate of water added to the upper part of the ammonia washing tower T3 is controlled by the control valve V3. The liquid phase at the bottom of the ammonia washing tower T3 is ammonia water, which is sent to the downstream equipment through the control valve V2.

[0037] Compared with the existing production equipment that first produces liquid ammonia and then gasifies the liquid ammonia into ammonia water, the liquid ammonia and ammonia water co-production device in this embodiment has the following characteristics: 1. While obtaining liquid ammonia in the ammonia separator S1, ammonia water can also be obtained in the ammonia washing tower T3, that is, two products are produced in one process without the need for a large number of new corresponding equipment.

[0038] 2. According to demand, the temperature of the gas after ammonia cooling can be controlled by controlling the ammonia cooling temperature of the ammonia cooler E4 and / or the evaporation liquid level of the ammonia cooler E4, so as to achieve the purpose of timely distribution and adjustment of the production ratio of liquid ammonia and ammonia water, that is, the ratio of liquid ammonia to ammonia water can be adjusted.

[0039] 3. Drying system PK1 can remove water carried in the raw gas and water generated by the deoxygenation reaction, and can also remove water in the circulating gas after water washing in the ammonia washing tower T3.

[0040] 4. In this embodiment, the flow control valve V3 of the water wash at the top of the ammonia washing tower T3 can be controlled to control the water flow rate, so as to flexibly control the ammonia concentration after the ammonia absorption at the bottom of the tower.

[0041] 5. Since the circulating gas has been washed and deammonified by the ammonia washing tower T3, the ammonia content in the mixture of the raw gas and the circulating gas entering the ammonia synthesis tower T2 is very low, the ammonia net value of the ammonia synthesis tower T2 is higher, the ammonia synthesis efficiency is improved, and the power of the circulating gas compressor C2 is reduced.

[0042] Example 2

[0043] In this embodiment, a method for co-producing liquid ammonia and ammonia water is provided, which is implemented based on the liquid ammonia and ammonia water co-production device in Example 1, and includes the following steps: Step S1, hydrogen and nitrogen are mixed in a required ratio and enter into a raw gas compressor C1, and the raw gas compressor C1 compresses the raw gas to the pressure required for ammonia synthesis; Step S2, the compressed raw gas in step S1 enters the deoxidation tower T1 from the top of the deoxidation tower T1, flows from top to bottom and contacts with the filler loaded with the deoxidizer filled in the deoxidation tower T1 to achieve deoxidation, and finally is discharged from the bottom of the deoxidation tower T1; Step S3, the raw gas after deoxygenation in step S2 is cooled by using a deoxygenation cooler E1; Step S4, the raw gas after the temperature reduction in step S3 enters the drying system PK1 from the top of the drying system PK1, and then is discharged from the bottom of the drying system PK1 to achieve drying and dehydration; Step S5, the raw gas after drying and dehydration in step S4 enters the circulating gas compressor C2, and is compressed again by the circulating gas compressor C2 to the pressure required for ammonia synthesis; Step S6, the raw gas compressed again in step S5 enters the heat exchanger E2 to preheat the raw gas, and the preheated raw gas enters the ammonia synthesis tower T2 from the top of the ammonia synthesis tower T2 to undergo an ammonia synthesis reaction, generating ammonia synthesis gas and being discharged from the bottom of the ammonia synthesis tower T2; wherein the ammonia synthesis gas is used as a heat source in the heat exchanger E2 to exchange heat with the raw gas with a relatively low temperature, thereby increasing the temperature of the raw gas and reducing the temperature of the ammonia synthesis gas; Step S7, the ammonia synthesis gas after heat exchange with the raw gas in step S6 enters the cooler E3 for further cooling, and then is further cooled to a preset low temperature by the ammonia cooler E4, and finally sent to the middle and lower part of the ammonia separator S1 for gas-liquid separation; the liquid phase separated in the ammonia separator S1 is liquid ammonia, which is discharged from the bottom of the ammonia separator S1 and sent to the downstream equipment through the control valve V1; Step S8, the gas phase separated in step S7 is discharged from the top of the ammonia separator S1 and sent to the lower part of the ammonia washing tower T3, flows from bottom to top and contacts with the water added from the upper part of the ammonia washing tower T3 and flows from top to bottom, and the ammonia in the gas phase is absorbed by the water, and the remaining gas phase, i.e., the circulating gas, is discharged from the top of the ammonia washing tower T3 and mixed with the raw gas cooled by the cooler E1 and sent to the drying system PK1; the liquid phase at the bottom of the ammonia washing tower T3 is ammonia water, which is sent to the downstream equipment through the control valve V2.

Claims

1. A device for co-producing liquid ammonia and ammonia water, characterized in that: include: A cooler E3, wherein the cooler E3 is used to cool the ammonia synthesis gas; an ammonia cooler E4, the ammonia cooler E4 being connected to the cooler E3 to further cool the ammonia synthesis gas; an ammonia separator S1, the ammonia separator S1 being connected to the ammonia cooler E4, for performing gas-liquid separation on the ammonia synthesis gas after cooling; An ammonia washing tower T3, the lower part of which is connected to the top of the ammonia separator S1; the upper part of which is also connected to water; The liquid phase separated at the bottom of the ammonia separator S1 is liquid ammonia; the gas phase separated at the top of the ammonia separator S1 flows from bottom to top after entering the ammonia washing tower T3, and contacts with water flowing from top to bottom in the ammonia washing tower T3, and the ammonia in the gas phase is absorbed by the water; the liquid phase at the bottom of the ammonia washing tower T3 is aqueous ammonia; the production ratio of liquid ammonia to aqueous ammonia can be adjusted by adjusting the ammonia cooling temperature and / or the evaporation liquid level in the ammonia cooler E4.

2. The liquid ammonia and ammonia water co-production device according to claim 1, characterized in that: The liquid ammonia at the bottom of the ammonia separator S1 is sent to the downstream equipment through the control valve V1.

3. The device for co-producing liquid ammonia and aqueous ammonia according to claim 1, characterized in that: The ammonia water at the bottom of the ammonia washing tower S1 is sent to the downstream equipment through the control valve V2.

4. The liquid ammonia and ammonia water co-production device according to any one of claims 1 to 3, characterized in that: Also includes: A deoxygenation tower T1, wherein the deoxygenation tower T1 is used to deoxygenate the raw gas; wherein the raw gas includes hydrogen and nitrogen; A deoxygenation cooler E1, which is connected to the bottom of the deoxygenation tower T1 and is used to cool the raw gas after deoxygenation in the deoxygenation tower T1; A drying system PK1, the top of which is connected to the deoxygenation cooler E1, for drying and dehydrating the raw gas after being cooled by the deoxygenation cooler E1; A circulating gas compressor C2, which is connected to the bottom of the drying system PK1 and is used to re-compress the raw gas after drying and dehydration by the drying system PK1; Ammonia synthesis tower T2, the top of the ammonia synthesis tower T2 is connected to the circulating gas compressor C2, so as to convert the raw gas compressed again by the circulating gas compressor C2 into ammonia synthesis gas, and discharge it from the bottom of the ammonia synthesis tower T2 to the cooler E3.

5. The liquid ammonia and ammonia water co-production device according to claim 4, characterized in that: Also includes: The raw gas compressor C1 is connected to the top of the deoxidation tower T1 and is used to compress the raw gas to the pressure required for ammonia synthesis through the raw gas compressor C1 and then send it to the deoxidation tower T1.

6. The device for co-producing liquid ammonia and aqueous ammonia according to claim 4, characterized in that: The drying system PK1 has one or more drying towers.

7. The device for co-producing liquid ammonia and ammonia water according to claim 4, characterized in that: Also includes: The heat exchanger E2 is located between the circulating gas compressor C2 and the ammonia synthesis tower T2; wherein the heat exchanger E2 uses the ammonia synthesis gas discharged from the bottom of the ammonia synthesis tower T2 as a heat source, and exchanges heat with the raw gas compressed again by the circulating gas compressor C2.

8. The device for co-producing liquid ammonia and ammonia water according to claim 4, characterized in that: The top of the ammonia washing tower T3 is connected to the top of the drying system PK1.

9. The device for co-producing liquid ammonia and ammonia water according to any one of claims 1 to 3 and 5 to 8, characterized in that: A cyclone separator is arranged in the tank body of the ammonia separator S1; a wire mesh demister is also arranged at the top outlet of the tank body.

10. A method for co-producing liquid ammonia and ammonia water, which is implemented based on the liquid ammonia and ammonia water co-production device according to any one of claims 1 to 9, characterized in that: After the ammonia synthesis gas is cooled in two stages in the cooler E3 and the ammonia cooler E4, the ammonia separator S1 is used for gas-liquid separation; the liquid phase separated by the ammonia separator S1 is liquid ammonia; the gas phase separated by the ammonia separator S1 contacts with water in the ammonia washing tower T3 to form ammonia water.

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