Ammonia process decarburization system for reducing water content of ammonium bicarbonate and operation method thereof

Abstract

The invention relates to an ammonia process decarburization system, the ammonia process decarburization system comprises an ammonia process decarburization unit, an ammonium bicarbonate treatment unit, an additive supply unit and a defoaming agent supply unit, the ammonia process decarburization unit is configured to be used for removing carbon dioxide from flue gas containing carbon dioxide with an ammonia absorbent to generate ammonium bicarbonate, the ammonium bicarbonate treatment unit is connected with the ammonia process decarburization unit and is configured to be used for treating an ammonium bicarbonate solution from the ammonia process decarburization unit; the additive supply unit is connected with the ammonium bicarbonate treatment unit and is configured to be used for supplying an additive for increasing the crystal grain size of ammonium bicarbonate to the ammonium bicarbonate treatment unit, and the defoaming agent supply unit is connected with the ammonia process decarburization unit and is configured to be used for supplying a defoaming agent to the ammonia process decarburization unit. In addition, the invention further relates to an operation method for the ammonia process decarburization system. Therefore, the water content of ammonium bicarbonate produced in ammonia decarburization can be effectively reduced.

Description

Technical Field

[0001] This application relates to the field of environmental protection technologies, and specifically to an ammonia-based decarbonization system for reducing the water content of ammonium bicarbonate and an ammonia-based decarbonization method, whereby the water content of ammonium bicarbonate produced in ammonia-based decarbonization can be effectively reduced. Background Art

[0002] Currently, the waste gas treatment efficiency of various industrial enterprises is generally low, or they are simply discharged into the atmosphere after desulfurization and dust removal treatment. A large amount of greenhouse gases such as carbon dioxide are discharged into the environment, causing a series of environmental problems such as accelerating global warming. Therefore, seeking an active and effective method for treating carbon dioxide gas has become one of the urgent problems to be solved by various countries. Ammonium bicarbonate is a quick-acting nitrogen fertilizer, soluble in water and easy to decompose, suitable for various crops and various soils, and carbon dioxide is one of the raw materials for preparing ammonium bicarbonate. Processing carbon dioxide gas in the waste gas of industrial enterprises into ammonium bicarbonate can not only solve the problem of directly discharging carbon dioxide into the atmosphere, but also produce ammonium bicarbonate fertilizer, which has become a research and development topic for those skilled in the art.

[0003] A device for producing ammonium bicarbonate is known. The device includes a cooling function area, an ammonium bicarbonate generation area, a carbon dioxide absorption area, and an ammonia removal function area. By controlling the generation of ammonium bicarbonate, carbon dioxide absorption, and ammonia removal in different areas, ammonium bicarbonate that can be used as a nitrogen fertilizer is produced by using ammonia to absorb carbon dioxide in the flue gas. However, the produced ammonium bicarbonate has small crystal particles, high water content, and is easy to agglomerate, seriously affecting the use of ammonium bicarbonate. Summary of the Invention

[0004] The purpose of this application is to provide an ammonia-based decarbonization system and its operation method that can overcome at least one defect in the prior art, whereby the water content of ammonium bicarbonate produced in ammonia-based decarbonization can be effectively reduced.

[0005] According to the first aspect of this application, an ammonia-based decarbonization system for reducing the water content of ammonium bicarbonate is proposed. It is characterized in that the ammonia-based decarbonization system includes an ammonia-based decarbonization unit, an ammonium bicarbonate treatment unit, an additive supply unit, and an antifoaming agent supply unit. Among them, the ammonia-based decarbonization unit is configured to remove carbon dioxide from the flue gas containing carbon dioxide with an ammonia absorbent to produce ammonium bicarbonate. Among them, the ammonium bicarbonate treatment unit is connected to the ammonia-based decarbonization unit and is configured to process the ammonium bicarbonate solution from the ammonia-based decarbonization unit, and the additive supply unit is connected to the ammonium bicarbonate treatment unit and is configured to supply an additive for increasing the crystal particle size of ammonium bicarbonate to the ammonium bicarbonate treatment unit, and the antifoaming agent supply unit is connected to the ammonia-based decarbonization unit and is configured to supply an antifoaming agent to the ammonia-based decarbonization unit.

[0006] The present application provides an ammonia-based decarbonization system and an operating method for the ammonia-based decarbonization system, by which it is possible to advantageously combine increasing the crystal size of ammonium bicarbonate and the solid-liquid separation of ammonium bicarbonate with an increased crystal size, especially centrifugal solid-liquid separation, to obtain by-product ammonium bicarbonate fertilizer with low water content.

[0007] Advantageously, the ammonia-based decarbonization system and its operating method according to some embodiments of the present application can combine reducing the foaming degree of the ammonia-based decarbonization unit, increasing the crystal size of ammonium bicarbonate, and the solid-liquid separation of ammonium bicarbonate with an increased crystal size to obtain by-product ammonium bicarbonate fertilizer with low water content. Advantageously, by reducing the foaming degree of the ammonia-based decarbonization unit, the nitrogen content of ammonium bicarbonate can be effectively increased and the water content can be reduced.

[0008] Further advantageously, the ammonia-based decarbonization system and its operating method according to some embodiments of the present application can effectively obtain by-product ammonium bicarbonate fertilizer with low water content when using additives and defoamers with simple compositions. Additives and defoamers with simple compositions are particularly advantageous because adding additives and / or defoamers with complex compositions in the process production is likely to cause interference effects and is not applicable to the ammonia-based decarbonization system.

[0009] In some embodiments, the ammonium bicarbonate treatment unit includes a crystallization device, and the additive supply unit is connected to the crystallization device and configured to supply the additive to the crystallization device.

[0010] In some embodiments, the additive supply unit includes an additive storage tank and a first metering device, and the first metering device is configured to quantitatively add the additive from the additive storage tank to the ammonium bicarbonate treatment unit.

[0011] In some embodiments, the metering device is configured to control the additive addition amount such that the additive content in ammonium bicarbonate is between 0.2 kg / t ammonium bicarbonate and 0.9 kg / t ammonium bicarbonate.

[0012] In some embodiments, the metering device is configured to control the additive addition amount such that the additive content in ammonium bicarbonate is between 0.4 kg / t ammonium bicarbonate and 0.7 kg / t ammonium bicarbonate.

[0013] 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-based decarbonization unit.

[0014] In some embodiments, the ammonium bicarbonate treatment unit includes a solid-liquid separation device, and the solid-liquid separation device is connected to the crystallization device.

[0015] In some embodiments, the solid-liquid separation device is configured as a centrifugal solid-liquid separation device.

[0016] In some embodiments, the additive comprises one or more of the following substances: pentadecylsulfonyl chloride, hexadecylsulfonyl chloride, heptadecylsulfonyl chloride, octadecylsulfonyl chloride, ammonium decylbenzenesulfonate, ammonium undecylbenzenesulfonate, and ammonium dodecylbenzenesulfonate.

[0017] In some embodiments, the defoamer supply unit includes a defoamer storage tank and a second metering device configured to quantitatively add the defoamer from the defoamer storage tank to the ammonia-based decarbonization unit.

[0018] In some embodiments, the defoamer storage tank is configured as a fatty acid storage tank and can adjust the addition amount of the defoamer in relation to the foam situation in the ammonia-based decarbonization unit via the second metering device.

[0019] In some embodiments, along the flue gas flow direction, the ammonia-based decarbonization unit sequentially includes a cooling functional area, an ammonium bicarbonate generation area, a carbon dioxide absorption area, and an ammonia removal functional area. Among them, the ammonium bicarbonate treatment unit is connected to the ammonium bicarbonate generation area of the ammonia-based decarbonization unit and is configured to treat ammonium bicarbonate from the ammonium bicarbonate generation area.

[0020] In some embodiments, the cooling functional area, the ammonium bicarbonate generation area, the carbon dioxide absorption area, and the ammonia removal functional area are combined in one tower or multiple towers.

[0021] In some embodiments, the cooling functional area is implemented in the first tower, the ammonium bicarbonate generation area and the carbon dioxide absorption area are implemented in the second tower, and the ammonia removal functional area is implemented in the third tower. Among them, in the second tower, the carbon dioxide absorption area is separated from the ammonium bicarbonate generation area above the ammonium bicarbonate generation area by a liquid collector that allows gas to pass through.

[0022] In some embodiments, 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.

[0023] 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.

[0024] In some embodiments, along the flue gas flow direction, the ammonia-based decarbonization unit sequentially includes a cooling functional area, an ammonium bicarbonate generation area, a carbon dioxide absorption area, and an ammonia removal functional area. Among them, the defoamer supply unit is connected to the ammonium bicarbonate generation area of the ammonia-based decarbonization unit and is configured to supply a defoamer to the ammonium bicarbonate generation area of the ammonia-based decarbonization unit.

[0025] In some embodiments, the defoamer supply unit is connected to the lower region of the ammonium bicarbonate generation zone and configured to supply a defoamer to the lower region of the ammonium bicarbonate generation zone.

[0026] In some embodiments, an ammonia desulfurization unit is provided upstream of the ammonia-based decarbonization unit to form an ammonia desulfurization and decarbonization system, wherein the ammonia desulfurization unit is connected to the cooling function zone of the ammonia-based decarbonization unit through a fourth pipeline, and the ammonia desulfurization unit is connected to the ammonia removal function zone of the ammonia-based decarbonization unit through a fifth pipeline.

[0027] According to a second aspect of the present application, there is provided an operating method for an ammonia-based decarbonization system according to some embodiments of the present application, characterized in that the operating method includes: cooling and crystallizing the ammonium bicarbonate solution from the ammonia-based decarbonization unit by means of a crystallization device; adding an additive for increasing the crystal size into the ammonium bicarbonate solution by means of an additive supply unit; and performing solid-liquid separation on the ammonium bicarbonate solution by means of a solid-liquid separation device.

[0028] In some embodiments, the operating method includes: adding a defoamer into the ammonia-based decarbonization unit by means of a defoamer supply unit.

[0029] In some embodiments, the operating method includes: adding a defoamer into the ammonium bicarbonate generation zone of the ammonia-based decarbonization unit by means of a defoamer supply unit.

[0030] In some embodiments, centrifugal solid-liquid separation is performed on the ammonium bicarbonate solution by means of a solid-liquid separation device.

[0031] In some embodiments, the operating pressure of the ammonia-based decarbonization unit and the operating pressure of the cooling crystallization of the crystallization device are maintained at atmospheric pressure.

[0032] In some embodiments, the temperature of the ammonium bicarbonate solution is maintained between 5°C and 40°C, preferably between 8°C and 30°C.

[0033] In some embodiments, 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%.

[0034] In some embodiments, along the flue gas flow direction, the ammonia-based decarbonization unit sequentially includes a cooling functional area, an ammonium bicarbonate generation area, a carbon dioxide absorption area, and an ammonia removal functional area, wherein; one or more stages of gas-liquid contact are provided for the cooling functional area to implement the cooling of the flue gas, so that the temperature of the flue gas in the cooling functional area is maintained at 5-40°C, preferably 8-30°C; one or more stages of gas-liquid contact are provided for the ammonium bicarbonate generation area, and in the circulating liquid in the ammonium bicarbonate generation area, the molar ratio of total ammonia to total carbon dioxide is controlled at 1-3, preferably 1-2; one or more stages of gas-liquid contact are provided for the carbon dioxide absorption area, and in the circulating liquid in the carbon dioxide absorption area 7, the molar ratio of total ammonia to total carbon dioxide is controlled at 1.2-4.5, preferably 1.4-3.5; at least one stage of gas-liquid contact is provided for the ammonia removal functional area, wherein the acidic ammonia-based desulfurization solution from the ammonia-based desulfurization unit is used to control the ammonia escape in the ammonia removal functional area.

[0035] In some embodiments, the ammonium sulfate content of the ammonium bicarbonate fertilizer produced by the ammonia-based decarbonization system is 0.001%-0.5%, preferably 0.001%-0.3%, and the water content is not higher than 5%, preferably 3.5%, more preferably 3%. Brief Description of the Drawings

[0036] Through the following detailed description of exemplary embodiments in conjunction with the drawings, the above and other aspects and advantages of the present application will become apparent. The drawings illustrate the principles of the present application by way of example. It should be noted that the drawings are not necessarily drawn to scale.

[0037] Figure 1 A schematic diagram of an ammonia-based decarbonization system according to some embodiments of the present application is shown. Detailed Description of Specific Embodiments

[0038] The present application will be described below with reference to the drawings, in which several embodiments of the present application are shown. 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 explain the protection scope 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 more additional embodiments.

[0039] It should be understood that the terms used herein are only for describing specific embodiments and are not intended to limit the present application. All terms used herein (including technical terms and scientific terms) have the meaning 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.

[0040] As used herein, the term "A or B" includes "A and B" as well as "A or B", and does not exclusively include only "A" or only "B", unless otherwise specifically stated.

[0041] 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. Moreover, the present application is not limited by any theory expressed or implied in the above technical field, background art, summary of the invention, or detailed description.

[0042] In addition, for reference purposes only, terms such as "first", "second", etc. may also be used herein, and "first", "second" may also refer to multiple "firsts", "seconds". For example, unless the context clearly indicates otherwise, the words "first", "second", and other such numerical words referring to structures or elements do not imply an order or sequence.

[0043] It should also be understood that when the term "comprising / including" is used herein, it indicates the presence of the stated features, wholes, steps, operations, units, and / or components, but does not exclude the presence or addition of one or more other features, wholes, steps, operations, units, and / or components and / or their combinations. Unless otherwise defined, all terms (including technical and scientific terms) are used herein in their ordinary meaning in the field to which the examples belong.

[0044] As described in the background art, the ammonium bicarbonate crystals produced by the currently known ammonia-based decarbonization system are small in particle size, high in water content, and prone to caking, seriously affecting the use of ammonium bicarbonate. For this reason, the present application proposes an ammonia-based decarbonization system and an operating method for the ammonia-based decarbonization system, whereby it is possible to advantageously combine increasing the crystal size of ammonium bicarbonate and solid-liquid separation of ammonium bicarbonate with an increased crystal size, especially centrifugal solid-liquid separation, to obtain a by-product ammonium bicarbonate fertilizer with a low water content.

[0045] Further advantageously, the ammonia-based decarbonization system and its operating method according to some embodiments of the present application can combine reducing the foaming degree of the ammonia-based decarbonization unit, increasing the crystal size of ammonium bicarbonate, and solid-liquid separation of ammonium bicarbonate with an increased crystal size to obtain a by-product ammonium bicarbonate fertilizer with a low water content. Advantageously, by reducing the foaming degree of the ammonia-based decarbonization unit, the nitrogen content of ammonium bicarbonate can be effectively increased and the water content can be reduced.

[0046] Further advantageously, the ammonia-based decarbonization system and its operating method according to some embodiments of the present application can effectively produce by-product ammonium bicarbonate fertilizers with low water content when using additives and defoamers with simple compositions. Additives and defoamers with simple compositions are particularly advantageous because adding additives and / or defoamers with complex compositions in the process production is likely to cause interference effects and is not suitable for the ammonia-based decarbonization system.

[0047] Next, refer to Figure 1 for a detailed introduction to the ammonia-based decarbonization system according to the exemplary embodiments of the present application. In fact, Figure 1 A schematic diagram of an ammonia-based desulfurization and decarbonization system is shown. The ammonia-based desulfurization and decarbonization system includes an ammonia-based desulfurization unit 23 and an ammonia-based decarbonization unit downstream of the ammonia-based desulfurization unit 23. In an embodiment not shown, a desulfurization unit, such as an ammonia-based desulfurization unit, may not be provided upstream of the ammonia-based decarbonization unit, and thus a simple ammonia-based decarbonization system is formed. The ammonia-based 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 of a thermal power plant and mainly contains pollutants sulfur dioxide and carbon dioxide. After the process gas 1 is desulfurized by the ammonia-based desulfurization unit 23, it is transported to the ammonia-based decarbonization unit as flue gas containing carbon dioxide. By-product ammonium sulfate fertilizer 24 can be obtained through the ammonia-based desulfurization unit 23.

[0048] As Figure 1 shown, along the flue gas flow direction, the ammonia-based decarbonization unit may sequentially include a cooling function area 2, an ammonium bicarbonate generation area 5, a carbon dioxide absorption area 7, and an ammonia removal function area 15. Here, the cooling function area 2 can be realized by a separate first tower. The ammonium bicarbonate generation area 5 and the carbon dioxide absorption area 7 are realized in a second tower, in which the carbon dioxide absorption area 7 is separated from the ammonium bicarbonate generation area 5 by a gas-permeable liquid collector 6 above the ammonium bicarbonate generation area 5. The ammonia removal function area 15 can be realized by a third tower.

[0049] The flue gas containing carbon dioxide first enters the cooling function area 2. The flue gas contacts the countercurrently sprayed circulating liquid in the cooling function area 2 and thus cools down. The circulating liquid can be process water. In order to form a coolant circulation for the cooling function area 2, a circulation pipeline can be arranged outside the first tower, and a cooling circulation pump 3 and a heat exchanger 4 are arranged on the circulation pipeline. One or more stages of gas-liquid contact can be arranged in the cooling function area 2. As Figure 1 shown, for example, two layers of circulating liquid distributors can be arranged in the cooling function area 2, through which the circulating liquid is sprayed downward onto the upward flowing flue gas to cool down the flue gas. The temperature of the flue gas in the cooling function area 2 can be controlled at 5 - 40°C, preferably 8 - 30°C, for example, about 18°C.

[0050] After being cooled in the cooling function area 2, the flue gas enters the ammonium bicarbonate generation area 5 through the flue. Here, the flue gas contacts the circulating liquid sprayed countercurrently, and a chemical reaction occurs to generate ammonium bicarbonate. The circulating liquid is circulated by the circulating pump 9, and the circulating liquid is cooled by the heat exchanger 8. One or more stages of gas-liquid contact can be provided in the ammonium bicarbonate generation area 5. As Figure 1 shown, a layer of circulating liquid sprayer can be provided in the ammonium bicarbonate generation area 5. In the ammonium bicarbonate generation area 5, in the circulating liquid, the molar ratio of total ammonia to total carbon dioxide can be controlled to be 1-3, preferably 1-2, for example 1.2-1.4. The total ammonia can include ammonia and ammonium ions. The total carbon dioxide can include free carbon dioxide and carbonated carbon dioxide. The temperature of the circulating liquid can be controlled to be 8-30°C, for example about 15°C.

[0051] After leaving the ammonium bicarbonate generation area 5 through the liquid collector 6, the flue gas enters the carbon dioxide absorption area 7. In the carbon dioxide absorption area 7, carbon dioxide in the flue gas reacts with the absorbent ammonia in the circulating liquid to generate ammonium carbonate or ammonium carbamate. For this purpose, the carbon dioxide absorption area 7 is equipped with an ammonia addition device 19 to add ammonia 20 to the carbon dioxide absorption area 7. The ammonia addition device 19 can be an ammonia addition tank, and the ammonia 20 can be 99.8 wt% liquid ammonia. The circulating liquid is circulated by the circulating pump 10, and the circulating liquid is cooled by a possible heat exchanger (not shown). One or more stages of gas-liquid contact can be provided in the carbon dioxide absorption area 7. As Figure 1 shown, two layers of circulating liquid sprayers can be provided in the carbon dioxide absorption area 7. The circulating liquid in the carbon dioxide absorption area 7 can partially flow to the ammonium bicarbonate generation area 5 through the pipeline schematically described in Figure 1 but not provided with reference numerals to achieve solution replenishment from the carbon dioxide absorption area 7 to the ammonium bicarbonate generation area 5. In the carbon dioxide absorption area 7, in the circulating liquid, the molar ratio of total ammonia to total carbon dioxide can be controlled to be 1.2-4.5, preferably 1.4-3.5, for example 1.5-2.5. The temperature of the circulating liquid can be controlled to be 20-30°C, for example about 25°C.

[0052] After leaving the carbon dioxide absorption area 7, the flue gas enters the ammonia removal function area 15. Here, the flue gas contacts the circulating liquid sprayed countercurrently with the liquid to absorb free ammonia from the flue gas. The clean flue gas 16 after removing free ammonia can meet the discharge standards. The circulating liquid is circulated by the circulating pump 17. One or more stages of gas-liquid contact can be provided in the ammonia removal function area 15. As Figure 1As shown, a layer of circulating liquid sprayer can be arranged in the ammonia removal functional area 15. Advantageously, the ammonia removal functional area 15 can obtain solution supplement from the cooling functional area 2 through the cooling circulation pump 3 of the cooling functional area 2. In the cooling functional area 2, condensed water can be effectively recovered from the flue gas with a higher temperature through cooling measures. The condensed water recovered in this way can be used as make-up liquid, and thus the ammonia-based decarbonization system of the present application, especially the ammonia-based decarbonization system integrated with an ammonia-based desulfurization device, i.e., the ammonia-based desulfurization and decarbonization system, can operate in a particularly water-saving manner.

[0053] The circulating liquid in the ammonium bicarbonate generation 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 can 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 return pipe 18. In some embodiments, the content of ammonium bicarbonate solids 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 generation area 5. In some embodiments, the solid-liquid separation device can be configured as a centrifugal solid-liquid separation device.

[0054] In the exemplary embodiment as Figure 1 shown, the ammonia-based decarbonization unit can have 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 ammonium bicarbonate. By combining increasing the crystal size of ammonium bicarbonate and the solid-liquid separation of ammonium bicarbonate with an increased crystal size, especially centrifugal solid-liquid separation, ammonium bicarbonate fertilizer with a low water content as a by-product can be advantageously obtained.

[0055] In some embodiments, the additive supply unit 21 can include an additive storage tank, such as a pentadecylsulfonyl chloride storage tank, and a first metering device, and the first metering device can be configured to quantitatively add the additive from the additive storage tank to the ammonium bicarbonate treatment unit. In some embodiments, the metering device can be configured to control the additive addition amount such that the additive content in ammonium bicarbonate is from 0.2 kg / t ammonium bicarbonate to 0.9 kg / t ammonium bicarbonate, preferably from 0.4 kg / t ammonium bicarbonate to 0.7 kg / t ammonium bicarbonate. In some embodiments, a sensor for detecting the crystal size of ammonium bicarbonate can also be provided for the crystallization device 12, and the addition amount of the additive can be automatically adjusted based on the measurement result of the sensor.

[0056] In some embodiments, the additive may include one or more of the following substances: pentadecylsulfonyl chloride, hexadecylsulfonyl chloride, heptadecylsulfonyl chloride, octadecylsulfonyl chloride, ammonium decylbenzenesulfonate, ammonium undecylbenzenesulfonate, and ammonium dodecylbenzenesulfonate. Particularly preferably, only pentadecylsulfonyl chloride may be added. This allows for the effective production of ammonium bicarbonate fertilizer with a low water content in the by-products while using an additive with a simple composition.

[0057] In an exemplary embodiment as Figure 1 shown, the ammonia-based decarbonization unit may have an antifoaming agent supply unit 22 assigned to the ammonium bicarbonate production zone 5, and the antifoaming agent supply unit 22 may be configured to supply an antifoaming agent to the ammonium bicarbonate production zone 5. Advantageously, the antifoaming agent supply unit may be connected to the lower region of the ammonium bicarbonate production zone and configured to supply an antifoaming agent to the lower region of the ammonium bicarbonate production zone. By adding the antifoaming agent, the foaming degree of the ammonium bicarbonate solution in the ammonium bicarbonate production zone 5 can be advantageously reduced, thereby increasing the nitrogen content of the ammonium bicarbonate delivered to the crystallization device 12 and reducing the water content.

[0058] In some embodiments, the antifoaming agent supply unit may include an antifoaming agent storage tank and a second metering device configured to quantitatively add the antifoaming agent from the antifoaming agent storage tank to the ammonia-based decarbonization unit.

[0059] In some embodiments, the antifoaming agent storage tank may be configured as a fatty acid storage tank and can adjust the addition amount of the antifoaming agent in relation to the foam situation in the ammonia-based decarbonization unit, such as in the ammonium bicarbonate production zone, via the second metering device. This allows for the effective production of ammonium bicarbonate fertilizer with a low water content in the by-products while using an antifoaming agent with a simple composition. A dedicated observation window may be provided to observe the foam situation in the ammonium bicarbonate production zone. Additionally or alternatively, a sensor for detecting the foam degree may also be provided for the ammonium bicarbonate production zone, and the addition amount of the antifoaming agent may be automatically adjusted based on the measurement results of the sensor.

[0060] To test the effectiveness of the solution of the present application, the inventors conducted an exemplary comparative test: in the case where there is no additive supply unit 21 and antifoaming agent supply unit 22, the average particle size of the ammonium bicarbonate particles produced under an exemplary operating condition is 0.15 mm, and the water content is approximately 4.5%. While in the case where the additive supply unit 21 and antifoaming agent supply unit 22 described in the ammonia-based decarbonization system according to some embodiments of the present application are adopted, the average particle size of the ammonium bicarbonate particles produced under the same exemplary operating condition is 0.33 mm, and the water content is approximately 2.5%.

[0061] The present application has been described thus, and it is obvious that the present application can be modified in many ways. Such variations should not be regarded as a departure from the spirit and scope of the present application, and all such modifications that are obvious to those skilled in the art are intended to be included within the scope of the following claims.

Claims

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

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

3. The ammonia-based decarbonization system according to claim 1, wherein The additive supply unit includes an additive storage tank and a first metering device. The first metering device is configured to quantitatively add the additive from the additive storage tank to the ammonium bicarbonate treatment unit.

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

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

6. The ammonia-based decarbonization system according to claim 2, characterized in that, The crystallization device is configured as a cooling crystallization device. The cooling crystallization device is configured to cool and crystallize the ammonium bicarbonate solution from the ammonia-based decarbonization unit; and / or The ammonium bicarbonate treatment unit includes a solid-liquid separation device. The solid-liquid separation device is connected to the crystallization device; and / or The solid-liquid separation device is configured as a centrifugal solid-liquid separation device; and / or The additive includes one or more of the following substances: pentadecylsulfonyl chloride, hexadecylsulfonyl chloride, heptadecylsulfonyl chloride, octadecylsulfonyl chloride, ammonium decylbenzenesulfonate, ammonium undecylbenzenesulfonate, and ammonium dodecylbenzenesulfonate; and / or The water content of the ammonium bicarbonate fertilizer produced by the ammonia-based decarbonization system is not higher than 3.5%, more preferably 3%; and / or The antifoaming agent supply unit includes an antifoaming agent storage tank and a second metering device. The second metering device is configured to quantitatively add the antifoaming agent from the antifoaming agent storage tank to the ammonia-based decarbonization unit; and / or The antifoaming agent storage tank is configured as a fatty acid storage tank, and the addition amount of the antifoaming agent can be adjusted in relation to the foam situation in the ammonia-based decarbonization unit via the second metering device.

7. The ammonia-based decarbonization system according to any one of claims 1 to 6, characterized in that, Along the flue gas flow direction, the ammonia-based decarbonization unit sequentially includes a cooling function area, an ammonium bicarbonate generation area, a carbon dioxide absorption area, and an ammonia removal function area. Among them, the ammonium bicarbonate treatment unit is connected to the ammonium bicarbonate generation area of the ammonia-based decarbonization unit and is configured to treat the ammonium bicarbonate from the ammonium bicarbonate generation area; and / or The cooling function area, the ammonium bicarbonate generation area, the carbon dioxide absorption area, and the ammonia removal function area are combined in one tower or multiple towers; and / or The cooling functional area is implemented in the first tower, the ammonium bicarbonate generation area and the carbon dioxide absorption area are implemented in the second tower, and the ammonia removal functional area is implemented in the third tower. Wherein, in the second tower, the carbon dioxide absorption area is separated from the ammonium bicarbonate generation area above the ammonium bicarbonate generation area by a liquid collector allowing gas to pass through; and / or 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; and / or One or more layers of circulating liquid distributors are respectively arranged in the cooling functional area, the ammonium bicarbonate generation area, the carbon dioxide absorption area, and the ammonia removal functional area; and / or The defoamer supply unit is connected to the ammonium bicarbonate generation area of the ammonia-based decarbonization unit and is configured to supply a defoamer to the ammonium bicarbonate generation area of the ammonia-based decarbonization unit; and / or The defoamer supply unit is connected to the lower area of the ammonium bicarbonate generation area and is configured to supply a defoamer to the lower area of the ammonium bicarbonate generation area; and / or An ammonia-based desulfurization unit is arranged upstream of the ammonia-based decarbonization unit to form an ammonia-based desulfurization and decarbonization system. Wherein, the ammonia-based desulfurization unit is connected to the cooling functional area of the ammonia-based decarbonization unit through a fourth pipeline, and the ammonia-based desulfurization unit is connected to the ammonia removal functional area of the ammonia-based decarbonization unit through a fifth pipeline.

8. A method for operating an ammonia-based decarbonization system according to any one of claims 1 to 7, characterized in that, The operation method includes: Cooling and crystallizing the ammonium bicarbonate solution from the ammonia-based decarbonization unit by means of a crystallization device; Adding an additive for increasing the crystal size into the ammonium bicarbonate solution by means of an additive supply unit; and Performing solid-liquid separation on the ammonium bicarbonate solution by means of a solid-liquid separation device.

9. The operating method according to claim 8, characterized in that, The operation method includes: adding a defoamer in the ammonia-based decarbonization unit by means of a defoamer supply unit; and / or the operation method includes: adding a defoamer in the ammonium bicarbonate generation area of the ammonia-based decarbonization unit by means of a defoamer supply unit; and / or performing centrifugal solid-liquid separation on the ammonium bicarbonate solution by means of a solid-liquid separation device; and / or keeping the operating pressure of the ammonia-based decarbonization unit and the operating pressure of the cooling and crystallization of the crystallization device at atmospheric pressure; and / or keeping the temperature of the ammonium bicarbonate solution between 5-40°C, preferably between 8-30°C; and / or keeping the ammonium bicarbonate solid content in the mother liquor separated by the solid-liquid separation device between 0.1%-5%, preferably between 0.1%-3%.

10. The operating method according to claim 8 or 9, characterized in that Along the flue gas flow direction, the ammonia-based decarbonization unit sequentially includes a cooling functional area, an ammonium bicarbonate generation area, a carbon dioxide absorption area, and an ammonia removal functional area. Wherein, One or more stages of gas-liquid contact are provided for the cooling functional area to cool down the flue gas, so that the temperature of the flue gas in the cooling functional area is kept between 5-40°C; One or more stages of gas-liquid contact are provided 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; One or more stages of gas-liquid contact are provided 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; At least one stage of gas-liquid contact is provided for the ammonia removal functional area, wherein the acidic ammonia desulfurization solution from the ammonia desulfurization unit is used to control ammonia slip in the ammonia removal functional area; and / or The water content of the ammonium bicarbonate fertilizer produced by the ammonia-based decarbonization system is not higher than 5%, preferably 3.5%, more preferably 3%; and / or the ammonium sulfate content of the ammonium bicarbonate fertilizer produced by the ammonia-based decarbonization system is 0.001% - 0.5%, preferably 0.001% - 0.3%.

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