Patent Application
20230373800
This application claims priority under 35 U.S.C. § 119 of Chinese Patent Application No. CN202210553353.9, filed on May 20, 2022, which is hereby incorporated in its entirety herein.
This application relates to environmental protection. Specifically, this application relates to a method and device for producing ammonium bicarbonate in an ammonia-based decarbonization system.
At present, the efficiency of waste gas treatment in various industrial enterprises is generally low, or the waste gas is discharged into the atmosphere after desulfurization and dust removal treatment, and a large amount of greenhouse gas such as CO2 is discharged into the environment, resulting in a series of environmental problems such as acceleration of global climate warming. Therefore, it is one of the urgent problems for all countries to find a positive and effective CO2 treatment method. Ammonium bicarbonate is a quick-acting nitrogen fertilizer with a molecular formula of NH4HCO3, which is soluble in water, easy to decompose, and applicable to various crops and various soils. Carbon dioxide is one of the raw materials for the production of ammonium bicarbonate. It would be desirable to process the CO2 in the waste gas streams in the industrial processes and convert it into ammonium bicarbonate. As such, the problem of directly discharging CO2 into the atmosphere can be reduced or eliminated, and ammonium bicarbonate fertilizers can be prepared.
Patent CN201010125082.4 discloses a production method for synthesizing ammonium bicarbonate fertilizers using CO2 waste gas. A process of generating ammonium bicarbonate through countercurrent contact between CO2 waste gas after dust removal and desulfurization of tail gas and concentrated ammonia water is used, ammonia gas in the previous procedure is recovered via an ammonia recovery tower, and the remaining tail gas is directly discharged to the atmosphere. In the process, ammonium bicarbonate can be generated by countercurrent contact between concentrated ammonia water and CO2-containing gas for absorption. However, because the temperature is not lowered, in principle the ammonium bicarbonate generation and CO2 absorption are not controlled individually, the absorption efficiency is low and the ammonia escape is high.
The objects and advantages of the invention will be apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which like reference characters refer to like parts throughout, and in which:
In
Apparatus and methods for producing ammonium bicarbonate in an ammonia-based decarbonization system are provided.
The apparatus may include a cooling function zone. The cooling function zone may be operable to cool process gas. The apparatus may include an ammonium bicarbonate generation zone. The ammonium bicarbonate generation zone may be operable to generate ammonium bicarbonate. The apparatus may include a carbon dioxide absorption zone. The carbon dioxide absorption zone may be operable to absorb, via multi-stage absorption, carbon dioxide from process gas. The apparatus may include an ammonia removal function zone. The ammonia removal function zone may be operable to remove ammonia from decarbonized process gas. The carbon dioxide absorption zone may apply absorbent ammonia to process gas for carbon dioxide removal.
The ammonia bicarbonate generation zone may apply less ammonia to process gas than one or more of the individual stages with the multi-stage absorption zone.
A first-stage within the carbon dioxide absorption zone may apply less ammonia than the immediate next stage to process gas. The first-stage may be subsequent to the ammonium bicarbonate generation zone.
A last-stage decarbonization absorption circulating liquid may apply less ammonia to process gas than a previous stage within the carbon dioxide absorption zone.
A first-stage within the carbon dioxide absorption zone may apply less than 20% of the total ammonia applied to the process gas. The first-stage may be subsequent to the ammonia bicarbonate generation zone.
Solid ammonium bicarbonate may be produced from the ammonium bicarbonate generated in the ammonium bicarbonate generation zone by a post-treatment system. Ammonium bicarbonate mother liquid may be returned to a first-stage within the carbon dioxide absorption zone. The first-stage may be subsequent to the ammonium bicarbonate generation zone.
One or more of the cooling function zone, the ammonium bicarbonate generation zone, the carbon dioxide absorption zone and the ammonia removal function zone may be combined in one or more towers. Equipment/components may be disposed between the function zones to allow the passage of gas.
Methods for producing ammonium bicarbonate in an ammonia-based decarbonization system are provided. The methods may include receiving desulfurized process gas. The methods may include causing the desulfurized process gas to flow, in sequence, through one or more of a cooling function zone, an ammonium bicarbonate generation zone, a multi-stage carbon dioxide absorption zone and an ammonia removal function zone. The cooling function zone may be configured to cool desulfurized process gas. The ammonium bicarbonate generation zone may be configured to generate an ammonium bicarbonate solution/slurry. The multi-stage carbon dioxide absorption zone may be configured to absorb carbon dioxide in desulfurized process gas. The ammonia removal function zone may be configured to remove ammonia in decarbonized process gas. The multi-stage carbon dioxide absorption zone may apply absorbent ammonia to the process gas for carbon dioxide removal.
A first-stage of the multi-stage carbon dioxide absorption zone may be subsequent to the ammonium bicarbonate generation zone. The first-stage may apply less ammonia than the next stage to process gas.
A last-stage decarbonization absorption circulating liquid may apply less ammonia to process gas than a previous stage within the multi-stage carbon dioxide absorption zone.
A first-stage of the multi-stage carbon dioxide absorption zone may be subsequent to the ammonium bicarbonate generation zone. The first-stage may apply less ammonia than the next stage to process gas. The first-stage carbon dioxide absorption zone may apply less ammonia than 20% of the total ammonia applied to process gas.
Solid ammonium bicarbonate may be produced from ammonium bicarbonate generated in the ammonium bicarbonate generation zone by a post-treatment system. Ammonium bicarbonate mother liquid may be returned to a first-stage within the multi-stage carbon dioxide absorption zone. The first-stage may be subsequent to the ammonium bicarbonate generation zone.
The cooling function zone may cool the process gas to a temperature in the range 10-30 degrees Celsius. The cooling function zone may be provided with one or more layers of circulating liquid distributor.
The ammonium bicarbonate generation zone may be provided with one or more layers of gas and liquid distributors. The carbon dioxide absorption zone may be provided with one or more layers of circulating liquid distributors. The ammonia removal function zone may be provided with one or more layers of circulating liquid distributors.
Circulating liquid in a subsequent (relative to the flow direction of flue gas,) stage of the multi-stage carbon dioxide absorption zone may flow to a previous stage within the multi-stage carbon dioxide absorption zone. Circulating liquid in a first-stage with in the multi-stage carbon dioxide absorption zone may flow to the ammonium bicarbonate generation zone.
The apparatus may include a device for producing ammonium bicarbonate in an ammonia-based decarbonization system. The device may include one or more of a cooling function zone, an ammonium bicarbonate generation zone, a carbon dioxide absorption zone, and an ammonia removal function zone. The cooling function zone may be configured to cool process gas. The ammonium bicarbonate generation zone may be configured to generate ammonium bicarbonate. The carbon dioxide absorption zone may be configured to absorb carbon dioxide in the process gas using multi-stage absorption. The ammonia removal function zone may be configured to remove ammonia in the decarbonized process gas. Absorbent ammonia for carbon dioxide removal may be mainly fed to the carbon dioxide absorption zone.
As used in the present disclosure, “absorbent ammonia for carbon dioxide removal is mainly fed to the carbon dioxide absorption zone” may be understood to refer to the following: that greater than 60 wt % (weight-percent), e.g., greater than 65 wt %, e.g., greater than 80 wt %, e.g., greater than 90 wt %, e.g., greater than 98 wt %, e.g., 100 wt % of the total absorbent ammonia used for carbon dioxide removal in the method/device may be introduced into the carbon dioxide absorption zone and/or may be fed into the stream of the carbon dioxide absorption zone.
In some embodiments, the ammonium bicarbonate generation zone may be fed with no ammonia.
The first-stage absorption zone subsequent to the ammonium bicarbonate generation zone may be fed with less ammonia than the next stage or no ammonia. The amount of ammonia added in the first-stage carbon dioxide absorption zone subsequent to the ammonium bicarbonate generation zone may be less than 20% of the total ammonia added.
The last-stage decarbonization absorption circulating liquid may be fed with less ammonia than the previous stage or no ammonia. The last-stage decarbonization absorption circulating liquid may be fed with 80 wt % or less, e.g., 50 wt % or less, e.g., 30 wt % or less of ammonia added in the previous-stage decarbonization absorption circulating liquid.
Solid ammonium bicarbonate may be produced from the ammonium bicarbonate generated in the ammonium bicarbonate generation zone by a post-treatment system. Ammonium bicarbonate mother liquid may be returned to the first-stage absorption zone subsequent to the ammonium bicarbonate generation zone.
One or more of the cooling function zone, the ammonium bicarbonate generation zone, the carbon dioxide absorption zone and the ammonia removal function zone may be combined in one or more towers. Equipment/components may be disposed between the function zones to allow the passage of gas.
The methods may include receiving desulfurized process gas. The methods may include causing the process gas to flow, in sequence, through a cooling function zone, an ammonium bicarbonate generation zone, a carbon dioxide absorption zone and an ammonia removal function zone. The cooling function zone may be configured to cool the process gas. The ammonium bicarbonate generation zone may be configured to generate an ammonium bicarbonate solution/slurry. The carbon dioxide absorption zone may be configured to absorb carbon dioxide in the process gas by means of multi-stage absorption. The ammonia removal function zone may be configured to remove ammonia in the decarbonized process gas. Absorbent ammonia for carbon dioxide removal is mainly fed to the carbon dioxide absorption zone.
The first-stage absorption zone subsequent to the ammonium bicarbonate generation zone may be fed with less ammonia than the next stage or no ammonia. The first-stage carbon dioxide absorption zone, subsequent to the ammonium bicarbonate generation zone, may be fed with less ammonia than 20% of the total ammonia fed in the method.
The last-stage decarbonization absorption circulating liquid may be fed with less ammonia than the previous stage or no ammonia. The last-stage decarbonization absorption circulating liquid may be fed with 80 wt % or less, e.g., 50 wt % or less, e.g., 30 wt % or less of ammonia added in the previous-stage decarbonization absorption circulating liquid.
Solid ammonium bicarbonate may be produced from the ammonium bicarbonate generated in the ammonium bicarbonate generation zone by a post-treatment system. Ammonium bicarbonate mother liquid may be returned to the first-stage absorption zone subsequent to the ammonium bicarbonate generation zone.
The cooling function zone may cool the process gas to 10-30° C.
The cooling function zone may be provided with one or more layers of circulating liquid distributor.
The ammonium bicarbonate generation zone may be provided with one or more layers of gas and liquid distributors.
The gas and liquid distributors may be selected from the group consisting of bubble distributors, liquid distribution spray distributors, and combinations thereof.
The carbon dioxide absorption zone may be provided with two or more layers of circulating liquid distributor.
The ammonia removal function zone may be provided with one or more layers of circulating liquid distributor. The circulating liquid may be used in the ammonia removal function zone may be water or an acidic solution.
Circulating liquid in the subsequent-stage carbon dioxide absorption zone may overflow to the previous-stage carbon dioxide absorption zone. Circulating liquid in the first-stage carbon dioxide absorption zone may overflow to the ammonium bicarbonate generation zone.
Those skilled in the art will understand that the embodiments described herein are only for illustrating the disclosure, rather than limiting the scope of the disclosure.
Illustrative embodiments of apparatus and methods in accordance with the principles of the disclosure will now be described with reference to the accompanying drawings, which form a part hereof. It is to be understood that other embodiments may be utilized and that structural, functional and procedural modifications, additions or omissions may be made, and features of illustrative embodiments, whether apparatus or method, may be combined, without departing from the scope and spirit of the disclosure.
An illustrative embodiment of the device/method of the disclosure is described below with reference to the accompanying drawings. CO2-containing process gas 1 after ammonia-based desulfurization first enters a cooling function zone 2. Here, the gas may be brought into countercurrent contact with circulating liquid for cooling, the circulating liquid may be circulated by a cooling circulating pump 3, and the circulating liquid may be cooled by a heat exchanger 4.
The cooled gas enters an ammonium bicarbonate generation zone 5. Here, the gas may be brought into countercurrent contact with the circulating liquid for reaction to generate ammonium bicarbonate, and the circulating liquid may be circulated by a circulating pump 9. The process gas leaving the ammonium bicarbonate generation zone 5 enters a first-stage carbon dioxide absorption zone 7. The first-stage carbon dioxide absorption zone 7 may be separated from the ammonium bicarbonate generation zone 5 by a liquid collector 6 allowing the passage of gas, and circulating liquid in the first-stage carbon dioxide absorption zone 7 flows to the ammonium bicarbonate generation zone 5.
In the first-stage carbon dioxide absorption zone 7, the gas may be brought into countercurrent contact with the circulating liquid for reaction to generate ammonium carbonate or ammonium carbamate, and the circulating liquid is circulated by a circulating pump 10. The first-stage carbon dioxide absorption zone 7 may be separated from a second-stage carbon dioxide absorption zone 8 by the liquid collector 6 allowing the passage of gas, and circulating liquid in the second-stage carbon dioxide absorption zone 8 may flow to the first-stage carbon dioxide absorption zone 7. Mother liquid from the solid-liquid separation of an ammonium bicarbonate post-treatment system may be returned to the first-stage carbon dioxide absorption zone 7.
The gas may enter the second-stage carbon dioxide absorption zone 8 after passing through the first-stage carbon dioxide absorption zone 7. The gas may be brought into countercurrent contact with the circulating liquid for reaction to further generate ammonium carbonate or ammonium carbamate. The circulating liquid may be circulated by a circulating pump 11.
The gas may enter a third-stage carbon dioxide absorption zone 13 after passing through the second-stage carbon dioxide absorption zone 8, the gas may be brought into countercurrent contact with the circulating liquid for reaction to further generate ammonium carbonate or ammonium carbamate, and the circulating liquid may be circulated by a circulating pump 12.
Ammonia 22 may be fed into the first-stage carbon dioxide absorption zone 7 and the second-stage carbon dioxide absorption zone 8 through a pipeline.
The gas after passing through the third-stage carbon dioxide absorption zone 13 may be further treated and then may enter a water-washing and ammonia removal function zone 14 and an acid-washing and ammonia removal function zone 24. Here, the gas is respectively brought into countercurrent contact with water and an acidic ammonium sulfate solution to absorb free ammonia, and the water is circulated by a circulating pump 16. The process gas 15 after ammonia removal may be discharged.
The circulating liquid in the ammonium bicarbonate generation zone 5 may be pumped into an ammonium bicarbonate crystallizer 17 through an ammonium bicarbonate discharge pump 23, and then may enter a solid-liquid separator 18. The obtained solid may be delivered to a packing machine 19 to produce solid ammonium bicarbonate 20. The obtained mother liquid may be returned to the first-stage carbon dioxide absorption zone 7.
The device as shown in
The gas cooled to 25° C. entered ammonium bicarbonate generation zone 5. Here, the process gas was brought into countercurrent contact with the circulating liquid for reaction to generate ammonium bicarbonate, and the circulating liquid was circulated by circulating pump 9. The process gas leaving the ammonium bicarbonate generation zone 5 entered first-stage carbon dioxide absorption zone 7. The first-stage carbon dioxide absorption zone 7 was separated from the ammonium bicarbonate generation zone 5 by a liquid collector 6 allowing the passage of gas, and circulating liquid in the first-stage carbon dioxide absorption zone 7 flowed to the ammonium bicarbonate generation zone 5.
In the first-stage carbon dioxide absorption zone 7, the gas was brought into countercurrent contact with the circulating liquid for reaction to generate ammonium carbonate or ammonium carbamate, and the circulating liquid was circulated by a circulating pump 10. The first-stage carbon dioxide absorption zone 7 was separated from a second-stage carbon dioxide absorption zone 8 by the liquid collector 6 allowing the passage of gas, and circulating liquid in the second-stage carbon dioxide absorption zone 8 flowed to the first-stage carbon dioxide absorption zone 7. Mother liquid from the solid-liquid separation of an ammonium bicarbonate post-treatment system was returned to the first-stage carbon dioxide absorption zone 7.
The gas after passing through the first-stage carbon dioxide absorption zone 7 entered the second-stage carbon dioxide absorption zone 8, the gas was brought into countercurrent contact with the circulating liquid for reaction to further generate ammonium bicarbonate or ammonium carbamate, and the circulating liquid was circulated by a circulating pump 11.
The gas after passing through the second-stage carbon dioxide absorption zone 8 entered a third-stage carbon dioxide absorption zone 13, the gas was brought into countercurrent contact with the circulating liquid for reaction to further generate ammonium bicarbonate or ammonium carbamate, and the circulating liquid was circulated by a circulating pump 12.
Ammonia 22 was fed into the first-stage carbon dioxide absorption zone 7 and the second-stage carbon dioxide absorption zone 8 through a pipeline. The amount of ammonia fed in the first-stage was 10%, and the amount of ammonia fed in the second stage was 90%.
The gas after passing through the second-stage carbon dioxide absorption zone 8 entered a water-washing and ammonia removal function zone 14 and acid-washing and ammonia removal function zone 24. Here, the gas was respectively brought into countercurrent contact with water and an ammonium sulfate solution to absorb free ammonia, and the water was circulated by circulating pump 16. The process gas 15 after ammonia removal was discharged. The water-washing and ammonia removal function zone 14 contained water. Components entrained in the process gas entered the circulating liquid during the circulation process. The circulating liquid contained components such as ammonium bicarbonate, a byproduct of previous ammonia-based decarbonization.
The circulating liquid in the ammonium bicarbonate generation zone 5 was pumped into an ammonium bicarbonate crystallizer 17 through an ammonium bicarbonate discharge pump 23, and then entered a solid-liquid separator 18. The obtained solid was delivered to a packing machine 19 to produce solid ammonium bicarbonate 20. The obtained mother liquid was returned to the first-stage carbon dioxide absorption zone 7.
The decarbonization used 99.6% anhydrous ammonia as absorbent, and the parameters of process gas 1 are shown in the following table:
The parameters of the cooled flue gas are shown in the following table:
The main parameters obtained after treatment by decarbonization absorption tower are shown in the following table:
The main parameters obtained after treatment by ammonia washing tower may be shown in the following table:
Compared with Example 1, only the amounts of ammonia fed are different. Ammonia was fed to the ammonium bicarbonate generation zone and the first-, second- and third-stage decarbonization absorption zones, and the amounts of ammonia fed to the four stages were equivalent.
Since the amounts of ammonia fed in the ammonium bicarbonate generation zone reached 25%, ammonium bicarbonate was not generated in the solution and ammonium bicarbonate crystals were not obtained. The amount of ammonia fed to the third-stage decarbonization absorption zone reached 25%, which increased the decarbonization ammonia escape. The ammonia escape of the process gas treated by the decarbonization absorption zone 6 reached 6000 ppm. Accordingly, the ammonia removal loads in the subsequent water-washing ammonia removal function zone 14 and acid-washing ammonia removal function zone 24 were increased.
The main parameters of gas obtained after decarbonization treatment are shown in the following table:
The apparatus and methods may include one or more of the following non-limiting aspects:
All ranges and parameters disclosed herein shall be understood to encompass any and all subranges subsumed therein, every number between the endpoints, and the endpoints. For example, a stated range of “1 to 10” should be considered to include any and all subranges between (and inclusive of) the minimum value of 1 and the maximum value of 10; that is, all subranges beginning with a minimum value of 1 or more (e.g. 1 to 6.1), and ending with a maximum value of 10 or less (e.g., 2.3 to 9.4, 3 to 8, 4 to 7), and to each number 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 contained within the range.
Thus, methods and devices for producing ammonium bicarbonate in an ammonia-based decarbonization system have been provided. Persons skilled in the art will appreciate that the disclosure may be practiced by other than the described embodiments, which are presented for purposes of illustration rather than of limitation. The disclosure is limited only by the claims that follow.
| Number | Date | Country | Kind |
|---|---|---|---|
| 202210553353.9 | May 2022 | CN | national |
