Ammonia method-based decarbonization system for reducing moisture content in ammonium bicarbonate and operation method therefor

Abstract

The present application relates to an ammonia method-based decarbonization system. The ammonia method-based decarbonization system comprises an ammonia method-based decarbonization unit, an ammonium bicarbonate treatment unit, an additive supply unit, and a defoaming agent supply unit. The ammonia method-based decarbonization unit is configured to use an ammonia absorbent to remove carbon dioxide from flue gas containing carbon dioxide to generate ammonium bicarbonate; the ammonium bicarbonate treatment unit is connected to the ammonia method-based decarbonization unit and is configured to treat an ammonium bicarbonate solution from the ammonia method-based decarbonization unit; the additive supply unit is connected to the ammonium bicarbonate treatment unit and is configured to supply to the ammonium bicarbonate treatment unit an additive for increasing the crystallization particle size of the ammonium bicarbonate; and the defoaming agent supply unit is connected to the ammonia method-based decarbonization unit and is configured to supply a defoaming agent to the ammonia method-based decarbonization unit. In addition, the present application further relates to an operation method for the ammonia method-based decarbonization system. Therefore, the moisture content of ammonium bicarbonate produced in ammonia method-based decarbonization can be effectively reduced.

Description

Ammonia decarbonization system for reducing water content of ammonium bicarbonate and operation method thereof Technical Field

[0001] The present application relates to the field of environmental protection technology, and specifically to an ammonia decarbonization system for reducing the water content of ammonium bicarbonate and an ammonia decarbonization method, thereby effectively reducing the water content of ammonium bicarbonate produced in the ammonia decarbonization. Background Art

[0002] Currently, industrial waste gas treatment efficiency is generally low, or waste gas is discharged into the atmosphere after only desulfurization and dust removal. This releases large amounts of greenhouse gases, such as carbon dioxide, into the environment, causing a series of environmental problems, including accelerated global warming. Therefore, finding a proactive and effective method for treating carbon dioxide has become a pressing issue for many countries. Ammonium bicarbonate is a fast-acting nitrogen fertilizer that is easily soluble in water and easily decomposes, making it suitable for a variety of crops and soils. Carbon dioxide is one of the raw materials for producing ammonium bicarbonate. Processing carbon dioxide from industrial waste gas into ammonium bicarbonate not only solves the problem of direct carbon dioxide discharge into the atmosphere but also produces ammonium bicarbonate fertilizer, a topic of research and development for existing technical personnel.

[0003] A known device for producing ammonium bicarbonate includes a cooling zone, an ammonium bicarbonate production zone, a carbon dioxide absorption zone, and an ammonia removal zone. By controlling the ammonium bicarbonate production, carbon dioxide absorption, and ammonia removal in separate zones, ammonia is used to absorb carbon dioxide from flue gas to produce ammonium bicarbonate, which can be used as a nitrogen fertilizer. However, the resulting ammonium bicarbonate crystals are small, have a high water content, and are prone to agglomeration, seriously affecting the ammonium bicarbonate's usability.

[0004] Summary of the Invention

[0005] The purpose of the present application is to provide an ammonia decarbonization system and an operating method thereof that can overcome at least one defect in the prior art, thereby effectively reducing the water content of ammonium bicarbonate produced in ammonia decarbonization.

[0006] According to a first aspect of the present application, an ammonia decarbonization system for reducing the water content of ammonium bicarbonate is proposed, characterized in that the ammonia decarbonization system includes an ammonia decarbonization unit, an ammonium bicarbonate treatment unit, an additive supply unit and a defoaming agent supply unit, wherein the ammonia decarbonization unit is configured to remove carbon dioxide from flue gas containing carbon dioxide with an ammonia absorbent to produce ammonium bicarbonate, wherein the ammonium bicarbonate treatment unit is connected to the ammonia decarbonization unit and configured to treat the ammonium bicarbonate solution from the ammonia decarbonization unit, and the additive supply unit is connected to the ammonium bicarbonate treatment unit and configured to supply an additive for increasing the crystal particle size of ammonium bicarbonate to the ammonium bicarbonate treatment unit, and the defoaming agent supply unit is connected to the ammonia decarbonization unit and configured to supply defoaming agent to the ammonia decarbonization unit.

[0007] The present application proposes an ammonia decarbonization system and an operating method for the ammonia decarbonization system, by which the increase in the crystal particle size of ammonium bicarbonate and the solid-liquid separation of the ammonium bicarbonate with the increased crystal particle size, especially the centrifugal solid-liquid separation, can be advantageously combined to obtain a by-product ammonium bicarbonate fertilizer with a low water content.

[0008] Advantageously, the ammonia decarbonization system and operating method according to some embodiments of the present application can combine reducing the foaming level in the ammonia decarbonization unit, increasing the crystal size of ammonium bicarbonate, and performing solid-liquid separation on the ammonium bicarbonate with the increased crystal size to produce ammonium bicarbonate fertilizer with low water content as a byproduct. Advantageously, reducing the foaming level in the ammonia decarbonization unit can effectively increase the nitrogen content of the ammonium bicarbonate and reduce its water content.

[0009] Further advantageously, the ammonia decarbonization system and operating method according to some embodiments of the present application can effectively produce low-water-content ammonium bicarbonate fertilizer as a byproduct while using simple additives and defoamers. Simple additives and defoamers are particularly advantageous because the addition of complex additives and / or defoamers to the process can easily cause interference and be unsuitable for ammonia decarbonization systems.

[0010] In some embodiments, the ammonium bicarbonate processing unit includes a crystallization device, and the additive supply unit is connected to the crystallization device and is configured to supply the additive to the crystallization device.

[0011] In some embodiments, the additive supply unit includes an additive storage tank and a first metering device configured to quantitatively add the additive from the additive storage tank to the ammonium bicarbonate treatment unit.

[0012] In some embodiments, the metering device is configured to control the amount of additive added so that the content of the additive in the ammonium bicarbonate is between 0.2 kg / t ammonium bicarbonate and 0.9 kg / t ammonium bicarbonate.

[0013] In some embodiments, the metering device is configured to control the amount of additive added so that the content of the additive in the ammonium bicarbonate is between 0.4 kg / t ammonium bicarbonate and 0.7 kg / t ammonium bicarbonate.

[0014] In some embodiments, the crystallization device is configured as a cooling crystallization device, and the cooling crystallization device is configured to cool and crystallize the ammonium bicarbonate solution from the ammonia decarbonization unit.

[0015] In some embodiments, the ammonium bicarbonate processing unit includes a solid-liquid separation device connected to the crystallization device.

[0016] In some embodiments, the solid-liquid separation device is configured as a centrifugal solid-liquid separation device.

[0017] In some embodiments, the additive includes one or more of the following: pentadecylsulfonyl chloride, hexadecylsulfonyl chloride, heptadecylsulfonyl chloride, octadecylsulfonyl chloride, decanylbenzenesulfonate, undecylbenzenesulfonate, and dodecylbenzenesulfonate.

[0018] In some embodiments, the defoaming agent supply unit includes a defoaming agent storage tank and a second metering device, wherein the second metering device is configured to quantitatively add the defoaming agent from the defoaming agent storage tank to the ammonia decarbonization unit.

[0019] In some embodiments, the defoaming agent storage tank is configured as a fatty acid storage tank, and the amount of defoaming agent added can be adjusted in relation to the foaming situation in the ammonia decarbonization unit via a second metering device.

[0020] In some embodiments, along the flue gas flow direction, the ammonia decarbonization unit includes a cooling functional area, an ammonium bicarbonate production area, a carbon dioxide absorption area and an ammonia removal functional area in sequence, wherein the ammonium bicarbonate treatment unit is connected to the ammonium bicarbonate production area of ​​the ammonia decarbonization unit and is configured to process ammonium bicarbonate from the ammonium bicarbonate production area.

[0021] In some embodiments, the cooling functional zone, the ammonium bicarbonate generation zone, the carbon dioxide absorption zone, and the ammonia removal functional zone are combined in one tower or multiple towers.

[0022] In some embodiments, the cooling functional zone is implemented in the first tower, the ammonium bicarbonate production zone and the carbon dioxide absorption zone are implemented in the second tower, and the ammonia removal functional zone is implemented in the third tower, wherein, in the second tower, the carbon dioxide absorption zone is separated from the ammonium bicarbonate production zone above the ammonium bicarbonate production zone by a liquid collector allowing gas to pass through.

[0023] In some embodiments, the cooling functional area is connected to the ammonia removal functional area through a first pipe, the ammonium bicarbonate generation area is connected to the carbon dioxide absorption area through a second pipe, and the carbon dioxide absorption area is connected to the ammonia removal functional area through a third pipe.

[0024] In some embodiments, one or more layers of circulating liquid distributors are respectively provided in the cooling functional area, the ammonium bicarbonate generation area, the carbon dioxide absorption area, and the ammonia removal functional area.

[0025] In some embodiments, along the flue gas flow direction, the ammonia decarbonization unit includes a cooling functional area, an ammonium bicarbonate generation area, a carbon dioxide absorption area and an ammonia removal functional area in sequence, wherein the defoaming agent supply unit is connected to the ammonium bicarbonate generation area of ​​the ammonia decarbonization unit and is configured to supply defoaming agent to the ammonium bicarbonate generation area of ​​the ammonia decarbonization unit.

[0026] In some embodiments, the antifoaming agent supply unit is connected to the lower area of ​​the ammonium bicarbonate production zone and is configured to supply the antifoaming agent to the lower area of ​​the ammonium bicarbonate production zone.

[0027] In some embodiments, an ammonia desulfurization unit is arranged upstream of the ammonia decarbonization unit to form an ammonia desulfurization and decarbonization system, wherein the ammonia desulfurization unit is connected to the cooling functional area of ​​the ammonia decarbonization unit through a fourth pipeline, and the ammonia desulfurization unit is connected to the ammonia removal functional area of ​​the ammonia decarbonization unit through a fifth pipeline.

[0028] According to the second aspect of the present application, an operating method for the ammonia decarbonization system according to some embodiments of the present application is proposed, characterized in that the operating method includes: cooling and crystallizing the ammonium bicarbonate solution from the ammonia decarbonization unit with the help of a crystallization device; adding an additive for increasing the crystal particle size to the ammonium bicarbonate solution with the help of an additive supply unit; and performing solid-liquid separation on the ammonium bicarbonate solution with the help of a solid-liquid separation device.

[0029] In some embodiments, the operating method includes: adding a defoaming agent into the ammonia decarbonization unit by means of a defoaming agent supply unit.

[0030] In some embodiments, the operation method includes: adding a defoaming agent into the ammonium bicarbonate generation zone of the ammonia decarbonization unit by means of a defoaming agent supply unit.

[0031] In some embodiments, the ammonium bicarbonate solution is subjected to centrifugal solid-liquid separation with the aid of a solid-liquid separation device.

[0032] In some embodiments, the operating pressure of the ammonia decarbonization unit and the operating pressure of the cooling crystallization of the crystallization equipment are maintained at normal pressure.

[0033] In some embodiments, the temperature of the ammonium bicarbonate solution is maintained between 5-40°C, preferably between 8-30°C.

[0034] In some embodiments, the solid content of ammonium bicarbonate in the mother liquor separated by the solid-liquid separation device is maintained between 0.1% and 5%, preferably between 0.1% and 3%.

[0035] In some embodiments, along the flue gas flow direction, the ammonia decarbonization unit includes a cooling functional area, an ammonium bicarbonate generation area, a carbon dioxide absorption area and an ammonia removal functional area in sequence, wherein: one or more gas-liquid contacts are set for the cooling functional area to cool the flue gas so that the flue gas temperature in the cooling functional area is maintained at 5-40°C, preferably 8-30°C; one or more gas-liquid contacts are set for the ammonium bicarbonate generation area, and the molar ratio of total ammonia to total carbon dioxide in the circulating liquid in the ammonium bicarbonate generation area is controlled at 1-3, preferably 1-2; one or more gas-liquid contacts are set for the carbon dioxide absorption area, and the molar ratio of total ammonia to total carbon dioxide in the circulating liquid in the carbon dioxide absorption area 7 is controlled at 1.2-4.5, preferably 1.4-3.5; at least one gas-liquid contact is set for the ammonia removal functional area, wherein the acidic ammonia desulfurization solution from the ammonia desulfurization unit is used to control ammonia escape from the ammonia removal functional area.

[0036] In some embodiments, the ammonium bicarbonate fertilizer produced by the ammonia decarbonization system has an ammonium sulfate content of 0.001%-0.5%, preferably 0.001%-0.3%, and a water content of no more than 5%, preferably 3.5%, and more preferably 3%. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The above and other aspects and advantages of the present application will become apparent from the following detailed description of exemplary embodiments in conjunction with the accompanying drawings, which illustrate the principles of the present application by way of example. It should be noted that the drawings are not necessarily drawn to scale.

[0038] FIG1 shows a schematic diagram of an ammonia decarbonization system according to some embodiments of the present application. DETAILED DESCRIPTION

[0039] The present application will be described below with reference to the accompanying drawings, which illustrate several embodiments of the present application. However, it should be understood that the present application can be presented in many different ways and is not limited to the embodiments described below; in fact, the embodiments described below are intended to make the present application more complete and fully illustrate the scope of protection of the present application to those skilled in the art. It should also be understood that the embodiments disclosed herein can be combined in various ways to provide many additional embodiments.

[0040] It should be understood that the terms used herein are only used to describe specific embodiments and are not intended to limit this application. All terms (including technical and scientific terms) used herein have the meanings commonly understood by those skilled in the art unless otherwise defined. For the sake of brevity and / or clarity, well-known functions or structures may not be described in detail.

[0041] Herein, the term "A or B" includes "A and B" and "A or B" rather than exclusively including "A" or only "B" unless specifically stated otherwise.

[0042] As used herein, the term "exemplary" means "serving as an example, instance, or illustration." Any implementation described herein as exemplary is not necessarily to be construed as preferred or advantageous over other implementations. Furthermore, this application is not to be bound by any expressed or implied theory presented in the foregoing technical field, background, summary, or detailed description.

[0043] In addition, for reference purposes only, terms such as "first" and "second" may also be used herein, and "first" and "second" may also refer to multiple "firsts" and "seconds." For example, the terms "first," "second," and other numerical terms referring to structures or elements do not imply a sequence or order unless the context clearly indicates otherwise.

[0044] It should also be understood that when the term "include / comprising" is used in this document, it indicates the presence of the specified features, integers, steps, operations, units and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, units and / or components and / or their combinations. Unless otherwise defined, all terms (including technical and scientific terms) are used in this document according to their common meaning in the field to which the examples belong.

[0045] As described in the background art, the ammonium bicarbonate crystals produced by currently known ammonia decarbonization systems are small in size, have a high water content, and are prone to agglomeration, seriously affecting the use of the ammonium bicarbonate. Therefore, the present application provides an ammonia decarbonization system and an operating method for the ammonia decarbonization system, which advantageously combines increasing the crystal size of ammonium bicarbonate with solid-liquid separation, particularly centrifugal solid-liquid separation, of the ammonium bicarbonate with the increased crystal size to produce a low-water-content ammonium bicarbonate fertilizer as a byproduct.

[0046] Further advantageously, the ammonia decarbonization system and operating method according to some embodiments of the present application can combine reducing the foaming level in the ammonia decarbonization unit, increasing the crystal size of ammonium bicarbonate, and performing solid-liquid separation on the ammonium bicarbonate with the increased crystal size to produce ammonium bicarbonate fertilizer with low water content as a byproduct. Advantageously, reducing the foaming level in the ammonia decarbonization unit can effectively increase the nitrogen content of the ammonium bicarbonate and reduce its water content.

[0047] Further advantageously, the ammonia decarbonization system and operating method according to some embodiments of the present application can effectively produce low-water-content ammonium bicarbonate fertilizer as a byproduct while using simple additives and defoamers. Simple additives and defoamers are particularly advantageous because the addition of complex additives and / or defoamers to the process can easily cause interference and be unsuitable for ammonia decarbonization systems.

[0048] Next, an ammonia decarbonization system according to an exemplary embodiment of the present application will be described in detail with reference to FIG1 . In fact, FIG1 shows a schematic diagram of an ammonia desulfurization and decarbonization system. The ammonia desulfurization and decarbonization system includes an ammonia desulfurization unit 23 and an ammonia decarbonization unit downstream of the ammonia desulfurization unit 23. In an embodiment not shown, a desulfurization unit, such as an ammonia desulfurization unit, may not be provided upstream of the ammonia decarbonization unit, and thus a simple ammonia decarbonization system is formed. The ammonia desulfurization unit itself may be known in the prior art and is therefore not described in more detail herein. The process gas 1, for example, comes from a coal-fired boiler in a thermal power plant and mainly contains the pollutants sulfur dioxide and carbon dioxide. After the sulfur dioxide is removed from the process gas 1 in the ammonia desulfurization unit 23, it is transported to the ammonia decarbonization unit as a flue gas containing carbon dioxide. By-product ammonium sulfate fertilizer 24 can be obtained through the ammonia desulfurization unit 23.

[0049] As shown in Figure 1, along the flue gas flow direction, the ammonia decarbonization unit can sequentially include a cooling functional zone 2, an ammonium bicarbonate production zone 5, a carbon dioxide absorption zone 7, and an ammonia removal functional zone 15. Here, the cooling functional zone 2 can be implemented by a single first tower. The ammonium bicarbonate production zone 5 and the carbon dioxide absorption zone 7 are implemented in a second tower. In the second tower, the carbon dioxide absorption zone 7 is separated from the ammonium bicarbonate production zone 5 above the ammonium bicarbonate production zone 5 by a liquid collector 6 that allows gas to pass through. The ammonia removal functional zone 15 can be implemented by a third tower.

[0050] The flue gas containing carbon dioxide first enters the cooling functional zone 2. In the cooling functional zone 2, the flue gas comes into contact with the countercurrent sprayed circulating liquid and is thereby cooled. The circulating liquid can be process water. In order to form a cooling liquid circulation for the cooling functional zone 2, a circulation pipeline can be arranged outside the first tower, and a cooling circulation pump 3 and a heat exchanger 4 can be arranged on the circulation pipeline. One or more stages of gas-liquid contact can be arranged in the cooling functional zone 2. As shown in Figure 1, two layers of circulating liquid distributors can be arranged in the cooling functional zone 2, for example, through which circulating liquid is sprayed downwardly to the flue gas flowing upward to cool the flue gas. The flue gas temperature in the cooling functional zone 2 can be controlled at 5 to 40°C, preferably 8 to 30°C, for example about 18°C.

[0051] After cooling in the cooling functional area 2, the flue gas enters the ammonium bicarbonate production area 5 through the flue. Here, the flue gas contacts the circulating liquid sprayed in countercurrent, undergoes a chemical reaction, and produces ammonium bicarbonate. The circulating liquid circulates through the circulating pump 9 and is cooled by the heat exchanger 8. One or more stages of gas-liquid contact can be set in the ammonium bicarbonate production area 5. As shown in Figure 1, a layer of circulating liquid sprayers can be set in the ammonium bicarbonate production area 5. In the ammonium bicarbonate production area 5, the molar ratio of total ammonia to total carbon dioxide in the circulating liquid can be controlled at 1 to 3, preferably 1 to 2, for example, 1.2 to 1.4. The total ammonia may include ammonia and ammonium ions. The total carbon dioxide may include free carbon dioxide and carbonized carbon dioxide. The temperature of the circulating liquid can be controlled at 8 to 30°C, for example, about 15°C.

[0052] After leaving the ammonium bicarbonate production zone 5 through the liquid collector 6, the flue gas enters the carbon dioxide absorption zone 7. In the carbon dioxide absorption zone 7, the carbon dioxide in the flue gas reacts with the absorbent ammonia in the circulating liquid to produce ammonium carbonate or ammonium carbamate. To this end, the carbon dioxide absorption zone 7 is equipped with an ammonia addition device 19 to add ammonia 20 to the carbon dioxide absorption zone 7. The ammonia addition device 19 can be an ammonia addition tank, and the ammonia 20 can be 99.8wt% liquid ammonia. The circulating liquid circulates through a circulating pump 10 and is cooled by a possible heat exchanger (not shown). One or more stages of gas-liquid contact can be set in the carbon dioxide absorption zone 7. As shown in Figure 1, two layers of circulating liquid sprayers can be set in the carbon dioxide absorption zone 7. The circulating liquid in the carbon dioxide absorption zone 7 can partially flow to the ammonium bicarbonate production zone 5 through a pipeline as schematically described in Figure 1 but not provided with a figure mark, so as to achieve solution replenishment from the carbon dioxide absorption zone 7 to the ammonium bicarbonate production zone 5. In the carbon dioxide absorption zone 7, the molar ratio of total ammonia to total carbon dioxide in the circulating liquid can be controlled to be 1.2 to 4.5, preferably 1.4 to 3.5, for example 1.5 to 2.5. The temperature of the circulating liquid can be controlled to be 20 to 30°C, for example about 25°C.

[0053] After leaving the carbon dioxide absorption zone 7, the flue gas enters the ammonia removal functional zone 15. Here, the flue gas contacts the circulating liquid sprayed in a countercurrent manner to absorb free ammonia from the flue gas. The clean flue gas 16 after the free ammonia is removed can be discharged in compliance with the standards. The circulating liquid circulates through the circulating pump 17. One or more stages of gas-liquid contact can be set in the ammonia removal functional zone 15. As shown in Figure 1, a layer of circulating liquid sprayers can be set in the ammonia removal functional zone 15. Advantageously, the ammonia removal functional zone 15 can obtain solution replenishment from the cooling functional zone 2 through the cooling circulation pump 3 of the cooling functional zone 2. Condensed water can be effectively recovered from the flue gas with higher temperature through cooling measures in the cooling functional zone 2. The condensed water recovered in this way can be used as replenishment, and thus the ammonia decarbonization system according to the present application, especially the ammonia decarbonization system integrated with an ammonia desulfurization device, that is, the ammonia desulfurization and decarbonization system can be operated in a particularly water-saving manner.

[0054] The circulating liquid in the ammonium bicarbonate production area 5 can be pumped into the ammonium bicarbonate treatment unit through the ammonium bicarbonate discharge pump 11 to produce solid ammonium bicarbonate fertilizer 14. The ammonium bicarbonate treatment unit may include a crystallization device 12 and a solid-liquid separation device 13. The mother liquor separated by the solid-liquid separation device 13 can be returned to the carbon dioxide absorption area 7 through the mother liquor reflux pipe 18. In some embodiments, the ammonium bicarbonate solid content in the mother liquor can be 0.1%-5%, preferably 0.1%-3%. In some embodiments, the crystallization device can be configured as a cooling crystallization device, and the cooling crystallization device can be configured to cool and crystallize the ammonium bicarbonate solution from the ammonium bicarbonate production area 5. In some embodiments, the solid-liquid separation device can be configured as a centrifugal solid-liquid separation device.

[0055] In the exemplary embodiment shown in FIG1 , the ammonia decarbonization unit may include an additive supply unit 21 assigned to the crystallization device 12, and the additive supply unit 21 is configured to supply an additive to the crystallization device 12 to increase the crystal size of the ammonium bicarbonate. By combining the increase in the crystal size of the ammonium bicarbonate with solid-liquid separation of the ammonium bicarbonate having the increased crystal size, in particular centrifugal solid-liquid separation, a low-water content ammonium bicarbonate fertilizer can be advantageously produced as a by-product.

[0056] In some embodiments, the additive supply unit 21 may include an additive storage tank, such as a pentadecylsulfonyl chloride storage tank, and a first metering device, wherein the first metering device may be configured to quantitatively add the additive from the additive storage tank to the ammonium bicarbonate processing unit. In some embodiments, the metering device may be configured to control the amount of additive added so that the additive content in the ammonium bicarbonate is between 0.2 kg / t ammonium bicarbonate and 0.9 kg / t ammonium bicarbonate, preferably between 0.4 kg / t ammonium bicarbonate and 0.7 kg / t ammonium bicarbonate. In some embodiments, a sensor for detecting the crystal particle size of the ammonium bicarbonate may also be provided for the crystallization device 12, and the amount of additive added may be automatically adjusted based on the measurement results of the sensor.

[0057] In certain embodiments, the additive may include one or more of the following substances: pentadecylsulfonyl chloride, hexadecylsulfonyl chloride, heptadecylsulfonyl chloride, octadecylsulfonyl chloride, decanylbenzenesulfonate, undecylbenzenesulfonate, and dodecylbenzenesulfonate. Particularly preferably, only pentadecylsulfonyl chloride may be added. This allows the use of simple additives to effectively produce a by-product ammonium bicarbonate fertilizer with low water content.

[0058] In the exemplary embodiment shown in FIG1 , the ammonia decarbonization unit may include a defoamer supply unit 22 assigned to the ammonium bicarbonate production zone 5. The defoamer supply unit 22 may be configured to supply defoamer to the ammonium bicarbonate production zone 5. Advantageously, the defoamer supply unit may be connected to and configured to supply defoamer to the lower region of the ammonium bicarbonate production zone. The addition of the defoamer may advantageously reduce the degree of foaming of the ammonium bicarbonate solution in the ammonium bicarbonate production zone 5, thereby increasing the nitrogen content and reducing the water content of the ammonium bicarbonate delivered to the crystallization device 12.

[0059] In some embodiments, the defoaming agent supply unit may include a defoaming agent storage tank and a second metering device configured to quantitatively add the defoaming agent from the defoaming agent storage tank to the ammonia decarbonization unit.

[0060] In some embodiments, the defoamer storage tank can be configured as a fatty acid storage tank, and the amount of defoamer added can be adjusted via a second metering device based on the foaming conditions within the ammonia decarbonization unit, for example, the ammonium bicarbonate production zone. This allows for the efficient production of low-water ammonium bicarbonate fertilizer as a byproduct while using a simple defoamer. A dedicated observation window can be provided to monitor the foaming conditions within the ammonium bicarbonate production zone. Additionally or alternatively, a sensor for detecting the foaming level in the ammonium bicarbonate production zone can be provided, and the amount of defoamer added can be automatically adjusted based on the sensor's measurement results.

[0061] To test the effectiveness of the solution of the present application, the inventors conducted an exemplary comparative test: without the additive supply unit 21 and the defoaming agent supply unit 22, the ammonium bicarbonate particles produced under an exemplary operating condition had an average particle size of 0.15 mm and a water content of approximately 4.5%. However, when the additive supply unit 21 and the defoaming agent supply unit 22 described in the ammonia decarbonization system according to some embodiments of the present application were used, the ammonium bicarbonate particles produced under the same exemplary operating conditions had an average particle size of 0.33 mm and a water content of approximately 2.5%.

[0062] The application being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the application, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

Claims

1. An ammonia decarbonization system for reducing the water content of ammonium bicarbonate, characterized in that: The ammonia decarbonization system includes an ammonia decarbonization unit, an ammonium bicarbonate treatment unit, an additive supply unit and a defoamer supply unit, wherein the ammonia decarbonization unit is configured to remove carbon dioxide from flue gas containing carbon dioxide with an ammonia absorbent to produce ammonium bicarbonate, wherein the ammonium bicarbonate treatment unit is connected to the ammonia decarbonization unit and configured to treat the ammonium bicarbonate solution from the ammonia decarbonization unit, and the additive supply unit is connected to the ammonium bicarbonate treatment unit and configured to supply an additive for increasing the crystal particle size of ammonium bicarbonate to the ammonium bicarbonate treatment unit, and the defoamer supply unit is connected to the ammonia decarbonization unit and configured to supply defoamer to the ammonia decarbonization unit.

2. The ammonia decarbonization system according to claim 1, characterized in that: The ammonium bicarbonate processing unit includes a crystallization device, and the additive supply unit is connected to the crystallization device and is configured to supply the additive to the crystallization device.

3. The ammonia decarbonization system according to claim 1, characterized in that: The additive supply unit includes an additive storage tank and a first metering device configured to quantitatively add the additive from the additive storage tank to the ammonium bicarbonate treatment unit.

4. The ammonia decarbonization system according to claim 3, characterized in that: The metering device is configured to control the amount of additive added so that the content of the additive in the ammonium bicarbonate is between 0.2 kg / t ammonium bicarbonate and 0.9 kg / t ammonium bicarbonate.

5. The ammonia decarbonization system according to claim 3, characterized in that: The metering device is configured to control the amount of additive added so that the additive content in the ammonium bicarbonate is between 0.4 kg / t ammonium bicarbonate and 0.7 kg / t ammonium bicarbonate.

6. The ammonia decarbonization system according to claim 2, characterized in that: The crystallization device is configured as a cooling crystallization device, and the cooling crystallization device is configured to cool and crystallize the ammonium bicarbonate solution from the ammonia decarbonization unit.

7. The ammonia decarbonization system according to claim 2, characterized in that: The ammonium bicarbonate processing unit comprises a solid-liquid separation device, and the solid-liquid separation device is connected to the crystallization device.

8. The ammonia decarbonization system according to claim 7, characterized in that: The solid-liquid separation equipment is configured as a centrifugal solid-liquid separation equipment.

9. The ammonia decarbonization system according to any one of claims 1 to 8, characterized in that: The additive includes one or more of the following: pentadecylsulfonyl chloride, hexadecylsulfonyl chloride, heptadecylsulfonyl chloride, octadecylsulfonyl chloride, ammonium dedecylbenzenesulfonate, ammonium undecylbenzenesulfonate, and ammonium dodecylbenzenesulfonate.

10. The ammonia decarbonization system according to any one of claims 1 to 8, characterized in that: The water content of the ammonium bicarbonate fertilizer produced by the ammonia decarbonization system is not higher than 3.5%, more preferably 3%.

11. The ammonia decarbonization system according to any one of claims 1 to 8, characterized in that: The defoamer supply unit includes a defoamer storage tank and a second metering device, wherein the second metering device is configured to quantitatively add the defoamer from the defoamer storage tank to the ammonia decarbonization unit.

12. The ammonia decarbonization system according to claim 11, characterized in that: The defoamer storage tank is configured as a fatty acid storage tank, and the amount of defoamer added can be adjusted in relation to the foam situation in the ammonia decarbonation unit via a second metering device.

13. The ammonia decarbonization system according to any one of claims 1 to 8, characterized in that: Along the flue gas flow direction, the ammonia decarbonization unit includes a cooling functional area, an ammonium bicarbonate production area, a carbon dioxide absorption area and an ammonia removal functional area in sequence, wherein the ammonium bicarbonate treatment unit is connected to the ammonium bicarbonate production area of ​​the ammonia decarbonization unit and is configured to process the ammonium bicarbonate from the ammonium bicarbonate production area.

14. The ammonia decarbonization system according to claim 13, characterized in that: The cooling functional area, the ammonium bicarbonate generating area, the carbon dioxide absorbing area and the ammonia removing functional area are combined in one tower or a plurality of towers.

15. The ammonia decarbonization system according to claim 14, characterized in that: The cooling functional zone is realized in the first tower, the ammonium bicarbonate production zone and the carbon dioxide absorption zone are realized in the second tower, and the ammonia removal functional zone is realized in the third tower, wherein, in the second tower, the carbon dioxide absorption zone is separated from the ammonium bicarbonate production zone above the ammonium bicarbonate production zone by a liquid collector allowing gas to pass through.

16. The ammonia decarbonization system according to claim 14 or 15, characterized in that: The cooling functional area is connected to the ammonia removal functional area through a first pipeline, the ammonium bicarbonate generation area is connected to the carbon dioxide absorption area through a second pipeline, and the carbon dioxide absorption area is connected to the ammonia removal functional area through a third pipeline.

17. The ammonia decarbonization system according to claim 14 or 15, characterized in that: One or more layers of circulating liquid distributors are respectively arranged in the cooling functional area, the ammonium bicarbonate generating area, the carbon dioxide absorbing area and the ammonia removing functional area.

18. The ammonia decarbonization system according to claim 13, characterized in that: The defoaming agent supply unit is connected to the ammonium bicarbonate production area of ​​the ammonia decarbonation unit and is configured to supply the defoaming agent to the ammonium bicarbonate production area of ​​the ammonia decarbonation unit.

19. The ammonia decarbonization system according to claim 18, characterized in that: The defoaming agent supply unit is connected to the lower area of ​​the ammonium bicarbonate production zone and is configured to supply the defoaming agent to the lower area of ​​the ammonium bicarbonate production zone.

20. The ammonia decarbonization system according to any one of claims 1 to 8, characterized in that: An ammonia desulfurization unit is arranged upstream of the ammonia decarbonization unit to form an ammonia desulfurization and decarbonization system, wherein the ammonia desulfurization unit is connected to the cooling functional area of ​​the ammonia decarbonization unit through a fourth pipeline, and the ammonia desulfurization unit is connected to the ammonia removal functional area of ​​the ammonia decarbonization unit through a fifth pipeline.

21. An operating method for an ammonia decarbonization system according to any one of claims 1 to 20, characterized in that: The operation method comprises: The ammonium bicarbonate solution from the ammonia decarbonization unit is cooled and crystallized by means of a crystallization device; adding an additive for increasing the crystal particle size into the ammonium bicarbonate solution by means of an additive supply unit; and The ammonium bicarbonate solution is separated into solid and liquid by means of a solid-liquid separation device.

22. The operating method according to claim 21, characterized in that: The operation method comprises: adding a defoamer into the ammonia decarbonization unit by means of a defoamer supply unit.

23. The operating method according to claim 22, characterized in that: The operation method comprises: adding a defoamer into the ammonium bicarbonate generation zone of the ammonia decarbonation unit by means of a defoamer supply unit.

24. The operating method according to claim 21, characterized in that: The ammonium bicarbonate solution is subjected to centrifugal solid-liquid separation by means of solid-liquid separation equipment.

25. The operating method according to claim 21, characterized in that: The operating pressure of the ammonia decarbonization unit and the operating pressure of the cooling crystallization of the crystallization equipment are maintained at normal pressure.

26. The operating method according to claim 21, characterized in that: The temperature of the ammonium bicarbonate solution is maintained between 5-40°C, preferably between 8-30°C.

27. The operating method according to claim 21, characterized in that: The ammonium bicarbonate solid content in the mother liquor separated by the solid-liquid separation device is maintained between 0.1% and 5%, preferably between 0.1% and 3%.

28. The operating method according to claim 21, characterized in that: Along the flue gas flow direction, the ammonia decarbonization unit includes a cooling functional area, an ammonium bicarbonate generation area, a carbon dioxide absorption area and an ammonia removal functional area in sequence, wherein: One or more gas-liquid contacts are provided for the cooling functional area to cool the flue gas so that the flue gas temperature in the cooling functional area is maintained at 5-40°C; One or more gas-liquid contacts are provided for the ammonium bicarbonate production area. In the process, the molar ratio of total ammonia to total carbon dioxide is controlled at 1 to 3; One or more gas-liquid contacts are provided for the carbon dioxide absorption zone, and the molar ratio of total ammonia to total carbon dioxide in the circulating liquid in the carbon dioxide absorption zone 7 is controlled to be 1.2 to 4.5; At least one stage of gas-liquid contact is provided for the ammonia removal functional zone, wherein the acidic ammonia desulfurization solution from the ammonia desulfurization unit is used to control ammonia escape from the ammonia removal functional zone.

29. The operating method according to claim 21, characterized in that: The water content of the ammonium bicarbonate fertilizer produced by the ammonia decarbonization system is not higher than 5%, preferably 3.5%, more preferably 3%; and / or the ammonium bicarbonate fertilizer produced by the ammonia decarbonization system has an ammonium sulfate content of 0.001%-0.5%, preferably 0.001%-0.3%.

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