Method and device for producing ammonium bicarbonate in ammonia-based decarbonization system
Patent Information
- Application Number
- IL305478
- Authority / Receiving Office
- IL · IL
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2022-05-20
- Filing Date
- 2023-05-19
- Publication Date
- 2026-08-01
AI Technical Summary
The existing ammonia decarbonization system has low absorption efficiency and serious ammonia escape, and cannot effectively increase the production of ammonium bicarbonate.
By setting up a cooling functional area, an ammonium bicarbonate generation area and a carbon dioxide absorption area, and introducing multi-stage absorption and zoning control in the ammonia removal functional area, the ammonium bicarbonate generation and CO2 absorption processes are optimized to reduce ammonia escape.
The absorption efficiency and ammonia escape control of the ammonia decarbonization process are significantly improved, and the output of ammonium bicarbonate is increased.
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Abstract
Description
A method and device for producing ammonium bicarbonate in an ammonia decarbonization system
[0001] CROSS-REFERENCE TO RELATED APPLICATIONS
[0002] This application claims the benefit of and priority to Chinese patent application No. CN 202210553353.9, filed on May 20, 2022, which is incorporated herein by reference in its entirety. Technical Field
[0003] The present invention belongs to the technical field of environmental protection, and in particular relates to a method and device for producing ammonium bicarbonate in an ammonia decarbonization system. Background Art
[0004] 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 CO2, into the environment, causing a series of environmental problems, including accelerated global warming. Therefore, finding a proactive and effective CO2 gas treatment method has become a pressing issue for countries worldwide. Ammonium bicarbonate is a fast-acting nitrogen fertilizer with the molecular formula NH4HCO3. It 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 ammonium bicarbonate production. Processing CO2 from industrial waste gas into ammonium bicarbonate not only reduces or eliminates the problem of CO2 being directly discharged into the atmosphere, but also produces ammonium bicarbonate fertilizer.
[0005] Patent application CN201010125082.4 discloses a method for synthesizing ammonium bicarbonate fertilizer from CO2 waste gas. The process involves countercurrent contact of CO2 waste gas, after dust removal and desulfurization, with concentrated ammonia to produce ammonium bicarbonate. Ammonia from the preceding process is recovered via an ammonia recovery tower, and the remaining exhaust gas is discharged directly into the atmosphere. While this process produces ammonium bicarbonate through countercurrent absorption of concentrated ammonia with CO2-containing gas, it lacks cooling and, in principle, lacks zoned control over ammonium bicarbonate production and CO2 absorption, resulting in low absorption efficiency and significant ammonia escape.
[0006] SUMMARY OF THE INVENTION
[0007] To overcome the low absorption efficiency and severe ammonia slip encountered in prior art ammonia-based decarbonization systems and effectively increase the yield of the byproduct ammonium bicarbonate, the inventors conducted diligent research. They discovered that by providing multiple functional zones and implementing zonal control over ammonium bicarbonate generation, CO2 absorption, and ammonia removal, they were able to achieve high absorption efficiency and effective ammonia slip control in the ammonia-based decarbonization process, while also significantly increasing ammonium bicarbonate production. This led to the completion of the present invention.
[0008] Therefore, an object of the present invention is to provide a device for producing ammonium bicarbonate in an ammonia decarbonization system, which includes a cooling functional area, an ammonium bicarbonate generation area, a carbon dioxide absorption area, and an ammonia removal functional area, wherein the cooling functional area is used to cool the process gas, the ammonium bicarbonate generation area is used to generate ammonium bicarbonate, the carbon dioxide absorption area is used to absorb carbon dioxide in the process gas, and multi-stage absorption is adopted. The ammonia removal functional area is used to remove ammonia in the process gas after decarbonization, and the absorbent ammonia used for removing carbon dioxide is mainly added from the carbon dioxide absorption area.
[0009] Another object of the present invention is to provide a method for producing ammonium bicarbonate in an ammonia decarbonization system, the method comprising:
[0010] The desulfurized process gas is received and made to flow through the cooling functional area, ammonium bicarbonate generation area, carbon dioxide absorption area, and ammonia removal functional area in sequence. The cooling functional area is used to cool the process gas, the ammonium bicarbonate generation area produces ammonium bicarbonate solution / slurry, the carbon dioxide absorption area is used to absorb carbon dioxide in the process gas using multi-stage absorption, and the ammonia removal functional area is used to remove ammonia in the decarbonized process gas.
[0011] The absorbent ammonia used to remove carbon dioxide is mainly added from the carbon dioxide absorption zone.
[0012] BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG1 is a schematic diagram of an apparatus / method according to some embodiments of the present disclosure.
[0014] The symbols in Figure 1 have the following meanings: 1. process gas; 2. cooling functional area; 3. cooling circulation pump; 4. heat exchanger; 5. ammonium bicarbonate production area; 6. liquid collector; 7. first-stage carbon dioxide absorption area; 8. second-stage carbon dioxide absorption area; 9. ammonium bicarbonate production area circulation pump; 10. first-stage carbon dioxide absorption area circulation pump; 11. second-stage carbon dioxide absorption area circulation pump; 12. third-stage carbon dioxide absorption area circulation pump; 13. third-stage carbon dioxide absorption area; 14. ammonia removal functional area water washing section; 15. gas after decarbonization; 16. ammonia removal functional area water washing circulation pump; 17. ammonium bicarbonate crystallizer; 18. solid-liquid separator; 19. packaging machine; 20. solid ammonium bicarbonate; 21. mother liquor reflux pipe; 22. ammonia; 23. ammonium bicarbonate discharge pump; 24. ammonia removal functional area pickling section; 25. ammonium sulfate solution from ammonia desulfurization; 26. solution returned to ammonia desulfurization.
[0015] Detailed Description of the Preferred Embodiments
[0016] In a first aspect, the present invention provides a device for producing ammonium bicarbonate in an ammonia decarbonization system, the device comprising a cooling functional area, an ammonium bicarbonate generation area, a carbon dioxide absorption area, and an ammonia removal functional area, wherein the cooling functional area is used to cool the process gas, the ammonium bicarbonate generation area is used to generate ammonium bicarbonate, the carbon dioxide absorption area is used to absorb carbon dioxide in the process gas, using multi-stage absorption, the ammonia removal functional area is used to remove ammonia in the process gas after decarbonization, and the absorbent ammonia used for removing carbon dioxide is mainly added from the carbon dioxide absorption area.
[0017] As used in the present disclosure, “absorbent ammonia for removing carbon dioxide is mainly added from the carbon dioxide absorption zone” means that greater than 60 weight %, for example, greater than 65 weight %, for example, greater than 80 weight %, for example, greater than 90 weight %, for example, greater than 98 weight %, for example, 100 weight % of all the absorbent ammonia for removing carbon dioxide in the method / apparatus of the present disclosure is introduced into the carbon dioxide absorption zone and / or is fed into the logistics of the carbon dioxide absorption zone.
[0018] In some embodiments, the amount of ammonia added to the ammonium bicarbonate generation zone is lower than the amount of ammonia added in the immediately following first-stage carbon dioxide absorption zone, or no ammonia is added.
[0019] In some embodiments, the first carbon dioxide absorption zone after the ammonium bicarbonate generation zone adds less or no ammonia compared to the other carbon dioxide absorption zones. Preferably, the amount of ammonia added to the first carbon dioxide absorption zone after the ammonium bicarbonate generation zone is less than 20% of the total ammonia added.
[0020] In some embodiments, the amount of ammonia added to the last stage carbon dioxide absorption zone is less than that of the previous stage or no ammonia is added. Preferably, the amount of ammonia added to the last stage carbon dioxide absorption zone is 80% by weight or less of the amount of ammonia added to the previous stage carbon dioxide absorption zone, such as 50% by weight or less, such as 30% by weight or less.
[0021] In some embodiments, the ammonium bicarbonate produced in the ammonium bicarbonate production zone is passed through a post-processing system to produce solid ammonium bicarbonate, and the ammonium bicarbonate mother liquor is returned to the first-stage carbon dioxide absorption zone after the ammonium bicarbonate production zone.
[0022] In some embodiments, the cooling functional area, ammonium bicarbonate generation area, carbon dioxide absorption area, and ammonia removal functional area can be combined into one tower or multiple towers, and equipment / components allowing gas to pass through are provided between the functional areas.
[0023] In a second aspect, the present disclosure provides a method for producing ammonium bicarbonate in an ammonia decarbonization system, the method comprising: receiving desulfurized process gas, and allowing the desulfurized process gas to flow sequentially through a cooling functional zone, an ammonium bicarbonate generation zone, a carbon dioxide absorption zone, and an ammonia removal functional zone, wherein the cooling functional zone is used to cool the desulfurized process gas, the ammonium bicarbonate generation zone produces an ammonium bicarbonate solution / slurry, the carbon dioxide absorption zone is used to absorb carbon dioxide in the process gas, using multi-stage absorption, and the ammonia removal functional zone is used to remove ammonia in the decarbonized process gas, wherein the absorbent ammonia used to remove carbon dioxide is mainly added from the carbon dioxide absorption zone.
[0024] In some embodiments of the method, the first carbon dioxide absorption zone after the ammonium bicarbonate generation zone adds less or no ammonia compared to the other carbon dioxide absorption zones. Preferably, the amount of ammonia added to the first carbon dioxide absorption zone after the ammonium bicarbonate generation zone is less than 20% of the total ammonia added.
[0025] In some embodiments of the method, the amount of ammonia added to the last stage carbon dioxide absorption zone is less than the amount of ammonia added to the previous stage carbon dioxide absorption zone, or no ammonia is added. Preferably, the amount of ammonia added to the last stage carbon dioxide absorption zone is 80% by weight or less, such as 50% by weight or less, such as 30% by weight or less, of the amount of ammonia added to the previous stage carbon dioxide absorption zone.
[0026] In some embodiments of the method, the ammonium bicarbonate produced in the ammonium bicarbonate production zone is passed through a post-treatment system to produce solid ammonium bicarbonate, and the ammonium bicarbonate mother liquor is returned to the first-stage absorption zone after the ammonium bicarbonate production zone.
[0027] In some embodiments of the method, the cooling functional zone cools the process gas to a temperature of 10°C to 30°C.
[0028] In some embodiments of the method, at least one layer of circulating liquid distributor is provided in the cooling functional area.
[0029] In some embodiments of the method, at least one layer of gas and liquid distributors is provided in the ammonium bicarbonate production area. The gas and liquid distributors can be of bubbling type, liquid distribution spray type, or a combination thereof.
[0030] In some embodiments of the method, the carbon dioxide absorption zone is provided with at least two layers or more of circulating liquid distributors.
[0031] In some embodiments of the method, the ammonia removal functional area is provided with at least one layer of circulating liquid distributor. The circulating liquid used in the ammonia removal functional area is preferably water or an acidic solution.
[0032] In some embodiments of the method, the circulating liquid from the subsequent carbon dioxide absorption zone in terms of the process gas flow direction overflows into the previous carbon dioxide absorption zone, and the circulating liquid from the first carbon dioxide absorption zone overflows into the ammonium bicarbonate production zone.
[0033] As those skilled in the art will appreciate, water may be used as the medium for each circulating liquid / spraying liquid in the method.
[0034] An exemplary embodiment of an apparatus / method according to the principles of the present disclosure is described below in conjunction with the accompanying drawings (which form a part of this disclosure). The CO2-containing process gas 1 after ammonia desulfurization first enters a cooling zone 2 where it is cooled by countercurrent contact with a circulating fluid. The circulating fluid is circulated through a cooling pump 3 and cooled by a heat exchanger 4.
[0035] The cooled gas enters the ammonium bicarbonate production zone 5, where it reacts with a countercurrent circulating liquid to produce ammonium bicarbonate. The circulating liquid is circulated by a circulating pump 9. The process gas leaving the ammonium bicarbonate production zone 5 enters the first-stage carbon dioxide absorption zone 7, which is separated from the ammonium bicarbonate production zone 5 by a gas-permeable liquid collector 6. The circulating liquid from the first-stage carbon dioxide absorption zone 7 flows to the ammonium bicarbonate production zone 5.
[0036] In the first-stage carbon dioxide absorption zone 7, the gas and circulating liquid react in countercurrent contact to form ammonium carbonate or ammonium carbamate. The circulating liquid is circulated by a circulating pump 10. The first-stage carbon dioxide absorption zone 7 and the second-stage carbon dioxide absorption zone 8 are separated by a liquid collector 6 that allows gas to pass through. The circulating liquid in the second-stage carbon dioxide absorption zone 8 flows to the first-stage carbon dioxide absorption zone 7. The mother liquor from the solid-liquid separation in the ammonium bicarbonate post-treatment system is returned to the first-stage carbon dioxide absorption zone 7.
[0037] The gas after passing through the first-stage carbon dioxide absorption zone 7 enters the second-stage carbon dioxide absorption zone 8 , where the gas reacts with the circulating liquid in countercurrent to further generate ammonium carbonate or ammonium carbamate. The circulating liquid circulates through the circulating pump 11 .
[0038] The gas after passing through the second-stage carbon dioxide absorption zone 8 enters the third-stage carbon dioxide absorption zone 13 , where the gas reacts with the circulating liquid in countercurrent to further generate ammonium carbonate or ammonium carbamate. The circulating liquid circulates through the circulating pump 12 .
[0039] Ammonia 22 is fed into the first-stage carbon dioxide absorption zone 7 and the second-stage carbon dioxide absorption zone 8 through a pipeline.
[0040] After further treatment in the third-stage carbon dioxide absorption zone 13, the gas enters the water washing and ammonia removal functional zone 14 and then enters the acid washing and ammonia removal functional zone 24, where the gas is contacted with water and acidic ammonium sulfate solution in countercurrent to absorb free ammonia, and the water is circulated by the circulation pump 16. The process gas 15 after ammonia removal is discharged, optionally after further water washing.
[0041] The circulating liquid of the ammonium bicarbonate production zone 5 is pumped into the ammonium bicarbonate crystallizer 17 through the ammonium bicarbonate discharge pump 23, and then enters the solid-liquid separator 18. The obtained solid is removed from the packaging machine 19 to produce solid ammonium bicarbonate 20, and the obtained mother liquor is refluxed to the first-stage carbon dioxide absorption zone 7.
[0042] Example 1
[0043] This embodiment was carried out using the apparatus shown in Figure 1. CO2-containing process gas 1 first enters cooling zone 2, where it is cooled by countercurrent contact with circulating liquid. The circulating liquid is circulated through cooling pump 3 and cooled by heat exchanger 4. The circulating liquid is water. During the circulation process, components entrained by the process gas may enter the circulating liquid, causing it to contain components such as ammonium sulfate, a byproduct of the previous ammonia-based desulfurization process.
[0044] The gas cooled to 25°C enters the ammonium bicarbonate production zone 5, where the process gas reacts with the circulating liquid in countercurrent flow to produce ammonium bicarbonate. The circulating liquid is circulated by a circulation pump 9. The process gas leaving the ammonium bicarbonate production zone 5 enters the first-stage carbon dioxide absorption zone 7, which is separated from the ammonium bicarbonate production zone 5 by a gas-permeable liquid collector 6. The circulating liquid from the first-stage carbon dioxide absorption zone 7 flows to the ammonium bicarbonate production zone 5.
[0045] In the first-stage carbon dioxide absorption zone 7, the gas and circulating liquid react in countercurrent contact to form ammonium carbonate or ammonium carbamate. The circulating liquid is circulated by a circulating pump 10. The first-stage carbon dioxide absorption zone 7 and the second-stage carbon dioxide absorption zone 8 are separated by a liquid collector 6 that allows gas to pass through. The circulating liquid in the second-stage carbon dioxide absorption zone 8 flows to the first-stage carbon dioxide absorption zone 7. The mother liquor from the solid-liquid separation in the ammonium bicarbonate post-treatment system is returned to the first-stage carbon dioxide absorption zone 7.
[0046] The gas after passing through the first-stage carbon dioxide absorption zone 7 enters the second-stage carbon dioxide absorption zone 8 , where the gas and the circulating liquid react in countercurrent to further generate ammonium bicarbonate or ammonium carbamate. The circulating liquid circulates through the circulating pump 11 .
[0047] The gas after passing through the second-stage carbon dioxide absorption zone 8 enters the third-stage carbon dioxide absorption zone 13 , where it reacts with the circulating liquid in countercurrent flow to further generate ammonium bicarbonate or ammonium carbamate. The circulating liquid circulates through the circulating pump 12 .
[0048] Ammonia 22 is added to the first-stage carbon dioxide absorption zone 7 and the second-stage carbon dioxide absorption zone 8 through a pipeline. The amount of ammonia added in the first stage is 10% by weight, and the amount of ammonia added in the second stage is 90% by weight.
[0049] After passing through the third-stage carbon dioxide absorption zone 13, the gas enters the water-washing and ammonia-removal zone 14 and the acid-washing and ammonia-removal zone 24. Here, the gas comes into countercurrent contact with water and ammonium sulfate solution, respectively, to absorb free ammonia. The water is circulated by a circulation pump 16. The deammonified process gas 15 is discharged. The water-washing and ammonia-removal zone 14 uses water as the circulating fluid, and during the circulation process, components entrained by the process gas may enter the circulating fluid, causing the circulating fluid to contain components such as ammonium bicarbonate, a by-product of the previous ammonia decarbonization process.
[0050] The circulating liquid of the ammonium bicarbonate production zone 5 is pumped into the ammonium bicarbonate crystallizer 17 through the ammonium bicarbonate discharge pump 23, and then enters the solid-liquid separator 18. The obtained solid is removed from the packaging machine 19 to produce solid ammonium bicarbonate 20, and the obtained mother liquor is refluxed to the first-stage carbon dioxide absorption zone 7.
[0051] Decarburization uses 99.6% liquid ammonia as the absorbent. The process gas 1 parameters are shown in the table below:
[0052] The flue gas parameters after cooling are shown in the table below:
[0053] The main parameters after treatment by the decarbonization absorption tower are shown in the table below:
[0054] The main parameters after treatment in the ammonia washing tower are shown in the table below:
[0055] Comparative Example 1
[0056] Compared with Example 1, the only difference is the addition of ammonia. Ammonia is added to the ammonium bicarbonate generation zone and the first, second and third stage carbon dioxide absorption zones, and the amount of ammonia added to the fourth stage is the same.
[0057] Since the amount of ammonia added to the ammonium bicarbonate generation zone reaches 25%, it is difficult for ammonium bicarbonate to form in the solution, and ammonium bicarbonate crystals cannot be obtained. The addition of 25% ammonia to the third-stage carbon dioxide absorption zone will lead to a significant increase in ammonia escape from the carbon dioxide absorption zone (the concentration of ammonia entrained in the process gas after treatment in the carbon dioxide absorption zone reaches 6000ppm). Accordingly, the subsequent ammonia removal load of the water washing and ammonia removal functional zone 14 and the acid washing and ammonia removal functional zone 24 increases.
[0058] The main parameters of the gas after decarbonization treatment are shown in the table below:
Claims
1. A device for producing ammonium bicarbonate in an ammonia decarbonization system, comprising a cooling functional area, an ammonium bicarbonate generation area, a carbon dioxide absorption area, and an ammonia removal functional area, wherein: The cooling functional area is used to cool the process gas. The ammonium bicarbonate generation area is used for ammonium bicarbonate generation. The carbon dioxide absorption zone is used to absorb carbon dioxide in the process gas, using multi-stage absorption. The ammonia removal functional area is used to remove ammonia from the process gas after decarbonization, and The absorbent ammonia used to remove carbon dioxide is mainly added from the carbon dioxide absorption zone.
2. The device according to claim 1, having at least one of the following features: - The amount of ammonia added to the ammonium bicarbonate generation zone is lower than the amount of ammonia added in the first-stage carbon dioxide absorption zone immediately following it, or no ammonia is added; - the first stage carbon dioxide absorption zone after the ammonium bicarbonate generation zone adds less ammonia or no ammonia compared to the other stages of carbon dioxide absorption zones, preferably the amount of ammonia added in the first stage carbon dioxide absorption zone after the ammonium bicarbonate generation zone is less than 20% of the total amount of ammonia added; -The amount of ammonia added in the last stage of carbon dioxide absorption zone is lower than that in the previous stage or no ammonia is added.
3. The device of claim 1, wherein the bicarbonate of ammonium produced in the bicarbonate of ammonium generation zone is produced into solid bicarbonate of ammonium by a post-processing system, and the bicarbonate of ammonium mother liquor is returned to the first-stage absorption zone after the bicarbonate of ammonium generation zone.
4. The device according to claim 1, wherein the cooling functional area, the ammonium bicarbonate generation area, the carbon dioxide absorption area, and the ammonia removal functional area are combined into one tower or multiple towers, and equipment / components allowing gas to pass through are provided between each functional area.
5. A method for producing ammonium bicarbonate using an ammonia decarbonization system, the method comprising: The desulfurized process gas is received and made to flow through the cooling functional area, ammonium bicarbonate generation area, carbon dioxide absorption area, and ammonia removal functional area in sequence, wherein: The cooling functional area is used to cool the process gas after desulfurization. The ammonium bicarbonate generation zone produces an ammonium bicarbonate solution / slurry, The carbon dioxide absorption zone is used to absorb carbon dioxide in the process gas, using multi-stage absorption. The ammonia removal functional area is used to remove ammonia from the process gas after decarbonization. The absorbent ammonia used to remove carbon dioxide is mainly added from the carbon dioxide absorption zone.
6. The method according to claim 5, wherein the method has at least one of the following characteristics: - the amount of ammonia added to the ammonium bicarbonate generation zone is lower than the amount of ammonia added to the first stage carbon dioxide absorption zone immediately following it or No ammonia added; - the first carbon dioxide absorption zone after the ammonium bicarbonate generation zone adds less ammonia or no ammonia compared to other carbon dioxide absorption zones, preferably the amount of ammonia added in the first carbon dioxide absorption zone after the ammonium bicarbonate generation zone is less than 20% of the total ammonia added; -The amount of ammonia added in the last stage of carbon dioxide absorption zone is lower than that in the previous stage or no ammonia is added.
7. The method according to claim 5, further comprising feeding the ammonium bicarbonate produced in the ammonium bicarbonate production zone to a post-treatment system to produce solid ammonium bicarbonate, and returning the produced ammonium bicarbonate mother liquor to the first absorption zone after the ammonium bicarbonate production zone.
8. The method of claim 5, wherein the method has at least one of the following characteristics: - The cooling functional area cools the process gas to 10°C-30°C; - The cooling functional area is provided with at least one layer of circulating liquid distributor; - The ammonium bicarbonate generation area is provided with at least one layer of gas and liquid distributors, preferably the gas and liquid distributors are selected from bubbling type, liquid distribution spray type or a combination thereof; - The carbon dioxide absorption zone is provided with at least one layer of circulating liquid distributor; -The ammonia removal functional area is provided with at least one layer of circulating liquid distributor.
9. The method of claim 5, wherein the circulating liquid of the subsequent carbon dioxide absorption zone in terms of the process gas flow direction flows to the preceding carbon dioxide absorption zone, and the circulating liquid of the first carbon dioxide absorption zone flows to the ammonium bicarbonate production zone.