Desulfurized gypsum calcium recycling system and method thereof

Abstract

The invention relates to the technical field of flue gas desulfurization gypsum solid waste utilization, and discloses a flue gas desulfurization gypsum calcium recycling system and a method thereof. The system comprises a gypsum reaction unit, a gypsum storage unit, a carbon dioxide micro-nano bubble generation unit and an ammonia water unit, and the gypsum storage unit comprises a gypsum storage device and a gypsum conveying pipeline capable of supplying gypsum to the gypsum reaction unit and the ammonia water unit; the carbon dioxide micro-nano bubble generation unit comprises a carbon dioxide storage device and a carbon dioxide micro-nano bubble generation device; the ammonia water unit comprises an ammonia water storage tank and a third pipeline for conveying materials to the gypsum reaction unit; the ammonia water storage tank and the carbon dioxide micro-nano bubble generating device are connected through a first pipeline provided with a first circulating pump and a second pipeline provided with a second circulating pump. According to the technical scheme, the reaction rate is increased, the material consumption of carbon dioxide is reduced, and ammonia escape is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of desulfurized gypsum solid waste utilization, and in particular to a desulfurized gypsum calcium recycling system and method. Background Art

[0002] A large amount of sulfur dioxide pollutants are generated during the combustion of coal in coal-fired power plants. Currently, the limestone-gypsum wet desulfurization process is used to absorb sulfur dioxide to achieve ultra-low emissions of flue gas. A large amount of desulfurization gypsum (the main component is CaSO4·2H2O) is produced in the process. Gypsum not only occupies land area, but also wastes resources. The limestone-gypsum wet desulfurization process mines at least 125 million tons of high-quality limestone each year, which has a certain impact on the ecological environment. How to convert desulfurization gypsum into calcium carbonate at low cost and low energy consumption, realize the calcium resource cycle in the desulfurization process, and produce high-value by-products at the same time is an important direction of technological development in recent years.

[0003] As shown in the chemical reaction formula, desulfurized gypsum reacts with ammonia water and CO2 in one step at room temperature to obtain calcium carbonate, ammonium sulfate and cyanuric acid.

[0004] CaSO4·2H2O+2NH3·H2O+CO2→CaCO3+(NH4)2SO4+3H2O

[0005] Among them, the gas-liquid mass transfer diffusion rate of carbon dioxide gas in the slurry affects the overall reaction efficiency. Generally speaking, the smaller the diameter of the bubble, the longer the residence time in the slurry, the larger the gas-liquid contact area, and the better the mass transfer effect, which is conducive to accelerating the progress of the chemical reaction. The traditional method is to pass carbon dioxide into the desulfurized gypsum reaction system through one or several aeration pipes, but the carbon dioxide dissolution rate of this method is low, part of the carbon dioxide cannot be completely absorbed, and the bubbles have a very short residence time below the slurry due to their buoyancy. When they are above the slurry surface, the bubbles burst, resulting in the waste of unreacted carbon dioxide. Therefore, how to increase the residence time of carbon dioxide gas in the slurry and the gas-liquid contact area is the key direction for improving the conversion rate and efficiency of calcium sulfate dihydrate to calcium carbonate. Summary of the invention

[0006] The purpose of the present invention is to overcome the problems in the prior art that in the process of converting desulfurized calcium gypsum into calcium carbonate, carbon dioxide has a short residence time in the slurry, a small gas-liquid contact area, and low mass transfer and reaction efficiency, and to provide a desulfurized calcium gypsum recycling system and method thereof. The technical scheme reduces the diameter of CO2 bubbles from millimeter level to micrometer level or even nanometer level and reacts in steps, prolongs the residence time, increases the gas-liquid contact area, thereby improving the mass transfer efficiency and accelerating the progress of the chemical reaction between gas and liquid, thereby improving the utilization rate of carbon dioxide and reducing ammonia escape.

[0007] In order to achieve the above-mentioned object, the first aspect of the present invention provides a desulfurized gypsum calcium recycling system, which comprises: a gypsum reaction unit, a gypsum storage unit, a carbon dioxide micro-nano bubble generating unit and an ammonia water unit, wherein the gypsum storage unit comprises a gypsum storage device and a gypsum conveying pipeline capable of supplying gypsum to the gypsum reaction unit and the ammonia water unit respectively; the carbon dioxide micro-nano bubble generating unit comprises a carbon dioxide storage device and a carbon dioxide micro-nano bubble generating device; the ammonia water unit comprises an ammonia water storage tank and a third pipeline for conveying materials to the gypsum reaction unit; the ammonia water storage tank and the carbon dioxide micro-nano bubble generating device are connected through a first pipeline provided with a first circulation pump and a second pipeline provided with a second circulation pump, so that the ammonia water storage tank can convey materials to the carbon dioxide micro-nano bubble generating device through the first pipeline, and the carbon dioxide micro-nano bubble generating device can convey materials to the ammonia water storage tank through the second pipeline; in the carbon dioxide micro-nano bubble generating device, the carbon dioxide gas from the carbon dioxide storage device is mixed with the material injected through the first pipeline to form a fluid with carbon dioxide micro- or nano-bubbles.

[0008] Preferably, the gypsum reaction unit includes a gypsum reaction device, a first stirring device, a slurry clear liquid circulation device, a slurry outlet, a slurry liquid-solid separation device and a solid-liquid separation device, wherein the gypsum reaction device is used to react the material obtained by the ammonia water unit with gypsum to obtain slurry; the first stirring device is used to stir the material in the gypsum reaction device; the slurry obtained by the gypsum reaction device enters the slurry liquid-solid separation device through the slurry outlet for solid-liquid separation, and part or all of the liquid phase obtained by the slurry liquid-solid separation device enters the gypsum reaction device through the slurry clear liquid circulation device; the solid phase obtained by the slurry liquid-solid separation device enters the solid-liquid separation device for further solid-liquid separation.

[0009] Preferably, the ammonia water unit also includes an ammonia water pump and a second stirring device, wherein the ammonia water pump is used to pump part of the material in the ammonia water storage tank into the gypsum reaction unit through the third pipeline and / or return another part of the material in the ammonia water storage tank to the ammonia water storage tank; and the second stirring device is used to stir the material in the ammonia water storage tank.

[0010] Preferably, the system further comprises a tail gas purification unit, and the tail gas purification unit is used to absorb the tail gas discharged from the gypsum reaction unit.

[0011] The second aspect of the present invention provides a desulfurized calcium gypsum recycling method, which is carried out in the desulfurized calcium gypsum recycling system according to any one of claims 1 to 4, and comprises the following steps:

[0012] (1) In the carbon dioxide micro-nano bubble generating device, the carbon dioxide gas from the carbon dioxide storage device is mixed with the material injected through the first pipeline to form a fluid with carbon dioxide micro- or nano-bubbles;

[0013] (2) The gypsum in the gypsum storage unit is introduced into the gypsum reaction unit, the material in the ammonia water unit is introduced into the carbon dioxide micro-nano bubble generating unit through a first pipeline provided with a first circulation pump for reaction, and then the material in the carbon dioxide micro-nano bubble generating unit is introduced into the ammonia water unit through a second pipeline provided with a second circulation pump for reaction; then part of the material in the ammonia water unit is introduced into the gypsum reaction unit through the third pipeline to react with gypsum to generate calcium carbonate; or, the gypsum in the gypsum storage unit is introduced into the ammonia water unit and the gypsum reaction unit, and then the material in the ammonia water unit is introduced into the carbon dioxide micro-nano bubble generating unit through a first pipeline provided with a first circulation pump for reaction, and then the material in the carbon dioxide micro-nano bubble generating unit is introduced into the ammonia water unit through a second pipeline provided with a second circulation pump for reaction; then part of the material in the ammonia water unit is introduced into the gypsum reaction unit through the third pipeline to react with gypsum to generate calcium carbonate.

[0014] Preferably, the method further comprises: returning another part of the material in the ammonia water unit to the ammonia water unit.

[0015] Preferably, the method further comprises: passing the tail gas discharged from the gypsum reaction unit into the tail gas purification unit for absorption.

[0016] Preferably, the method further includes: in the gypsum reaction unit, the slurry discharged from the gypsum reaction device is transported to the slurry liquid-solid separation device through the slurry outlet for solid-liquid separation, and part or all of the liquid phase obtained by the treatment of the slurry liquid-solid separation device enters the gypsum reaction device through the slurry clear liquid circulation device; the solid phase obtained by the treatment of the slurry liquid-solid separation device is transported to the solid-liquid separation device for further solid-liquid separation to obtain and recover calcium carbonate solid.

[0017] Preferably, the method further comprises: transporting the material discharged from the gypsum reaction device to the carbon dioxide micro-nano bubble generating device via the first circulation pump.

[0018] Preferably, the pH value of the material in the carbon dioxide micro-nano bubble generating device is 6-10.5.

[0019] Compared with the prior art, the present invention has the following technical effects:

[0020] (1) According to the desulfurized calcium gypsum recycling system of the present invention, the characteristics of micro-nano bubbles, such as large specific surface area, slow floating speed and high mass transfer efficiency, are fully utilized to improve the carbon dioxide absorption efficiency, accelerate the reaction of ammonia water and carbon dioxide, and effectively reduce the ammonia escape content; and increase the residence time of micro-nano bubbles in the carbon dioxide micro-nano bubble generation unit; by allowing unreacted micro-nano bubbles to continue to enter the ammonia water unit for reaction, the utilization rate of carbon dioxide is improved;

[0021] (2) In the desulfurized gypsum calcium recycling system of the present invention, micro-nano carbon dioxide bubbles can react with ammonia water in the carbon dioxide micro-nano bubble generation unit to generate ammonium bicarbonate and ammonium carbonate, and then enter the gypsum reaction unit to continue to react with gypsum, and the pH value in each unit is controlled separately, so that the alkaline solution is more likely to react with carbon dioxide, thereby accelerating the reaction rate of calcium sulfate and ammonium carbonate, promoting the occurrence of calcium sulfate reaction, reducing carbon dioxide consumption, and reducing ammonia escape; in a more preferred case, the micro-nano carbon dioxide bubbles can also pre-react with the ammonia water gypsum mixed slurry, which is more conducive to reducing the concentration of ammonium carbonate in the carbon dioxide micro-nano bubble generation unit and the ammonia water unit, and promoting the continued reaction of ammonia water and carbon dioxide;

[0022] (3) According to the desulfurized gypsum calcium recycling method of the present invention, the alkalinity of ammonia water and the acidity of carbon dioxide are utilized, and micro-nano carbon dioxide bubbles are used to react with ammonia water alone, thereby accelerating the reaction rate of the two, achieving efficient absorption and capture of carbon dioxide, and reducing ammonia escape caused by unreacted carbon dioxide;

[0023] (4) In a further preferred method, the concentration of ammonium carbonate is reduced by reacting micro-nano carbon dioxide bubbles with the ammonia-gypsum mixed slurry, which is conducive to the positive reaction of carbon dioxide and ammonia;

[0024] (5) The desulfurized gypsum calcium recycling system and method described in the present invention are suitable for the resource utilization of phosphogypsum. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the process flow of the desulfurized gypsum calcium recycling system described in the present invention.

[0026] Description of Reference Numerals

[0027] 1. Gypsum reaction unit; 101. Gypsum reaction device; 102. First stirring device; 103. Slurry clear liquid circulation device; 104. pH monitoring device; 105. Slurry outlet; 106. Slurry liquid-solid separation device; 107. Solid-liquid separation device; 108. Demisting device; 2. Tail gas purification unit; 201. Spraying device; 202. Purification liquid circulation device; 3. Gypsum storage unit; 301. Gypsum storage device; 302. Gypsum quantitative feeding device; 4. Carbon dioxide micro-nano bubble generation unit; 401. Carbon dioxide storage device; 402. First circulation pump; 403. Carbon dioxide micro-nano bubble generation device; 404. First pH detection device; 405. Second circulation pump; 5. Ammonia water unit; 501. Ammonia water pump; 502. Circulation valve; 503. Second pH detection device; 504. Second stirring device; 505. Ammonia water storage tank. DETAILED DESCRIPTION

[0028] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0029] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0030] like Figure 1As shown, the desulfurized gypsum calcium recycling system of the present invention comprises: a gypsum reaction unit 1, a gypsum storage unit 3, a carbon dioxide micro-nano bubble generating unit 4 and an ammonia water unit 5, wherein the gypsum storage unit 3 comprises a gypsum storage device 301 and a gypsum conveying pipeline capable of supplying gypsum to the gypsum reaction unit 1 and the ammonia water unit 5 respectively; the carbon dioxide micro-nano bubble generating unit 4 comprises a carbon dioxide storage device 401 and a carbon dioxide micro-nano bubble generating device 403; the ammonia water unit 5 comprises an ammonia water storage tank 505 and a third pipeline for conveying materials to the gypsum reaction unit 1; the ammonia water storage tank 505 and the carbon dioxide micro-nano bubble generating unit 403 are connected to the ammonia water storage tank 505. The nano bubble generating device 403 is connected by a first pipeline provided with a first circulating pump 402 and a second pipeline provided with a second circulating pump 405, so that the ammonia storage tank 505 can transport materials to the carbon dioxide micro-nano bubble generating device 403 through the first pipeline, and the carbon dioxide micro-nano bubble generating device 403 can transport materials to the ammonia storage tank 505 through the second pipeline; in the carbon dioxide micro-nano bubble generating device 403, the carbon dioxide gas from the carbon dioxide storage device 401 is mixed with the material injected through the first pipeline to form a fluid with carbon dioxide micro- or nano-bubbles. According to the desulfurized gypsum calcium recycling system of the present invention, the carbon dioxide absorption efficiency is improved, the reaction rate of ammonia water and carbon dioxide is accelerated, the reaction rate of calcium sulfate and ammonium carbonate is accelerated, the material consumption of carbon dioxide is reduced, and ammonia escape is reduced; micro-nano carbon dioxide bubbles can also react with ammonia water gypsum mixed slurry, which is more conducive to reducing the concentration of ammonium carbonate in the carbon dioxide micro-nano bubble generating unit and the ammonia water unit, and promoting the continued reaction of ammonia water and carbon dioxide.

[0031] In the desulfurized gypsum calcium recycling system of the present invention, in order to improve the utilization rate of carbon dioxide and ammonia water, the gypsum reaction unit 1 preferably includes a gypsum reaction device 101, a first stirring device 102, a slurry clear liquid circulation device 103, a slurry outlet 105, a slurry liquid-solid separation device 106 and a solid-liquid separation device 107, wherein the gypsum reaction device 101 is used to react the material obtained by the treatment of the ammonia water unit 5 with gypsum to obtain slurry; the first stirring device 102 is used to stir the material in the gypsum reaction device 101; the slurry obtained by the treatment of the gypsum reaction device 101 enters the slurry liquid-solid separation device 106 through the slurry outlet 105 for solid-liquid separation, and part or all of the liquid phase obtained by the treatment of the slurry liquid-solid separation device 106 enters the gypsum reaction device 101 through the slurry clear liquid circulation device 103; the solid phase obtained by the treatment of the slurry liquid-solid separation device 106 enters the solid-liquid separation device 107 for further solid-liquid separation. In some embodiments, part of the liquid phase processed by the slurry liquid-solid separation device 106 enters the gypsum reaction device 101 through the slurry clear liquid circulation device 103; the other part of the liquid phase processed by the slurry liquid-solid separation device 106 is discharged.

[0032] In the desulfurized gypsum calcium recycling system described in the present invention, in order to improve the reaction efficiency of ammonium carbonate and gypsum, the gypsum reaction unit 1 preferably also includes a pH monitoring device 104, and the pH monitoring device 104 is used to monitor the pH value of the material in the gypsum reaction device 101, thereby adjusting the pH to promote the reaction of ammonium carbonate and gypsum.

[0033] In the desulfurized calcium gypsum recycling system of the present invention, in order to improve the utilization rate of raw materials, the gypsum reaction unit 1 preferably also includes a demisting device 108, and the demisting device 108 is used to remove the mist and entrained liquid phase in the gas phase in the gypsum reaction unit 101.

[0034] In the desulfurized gypsum calcium recycling system described in the present invention, in order to improve the reaction efficiency of carbon dioxide and ammonia water, the carbon dioxide micro-nano bubble generating unit 4 preferably includes a first pH detection device 404, and the first pH detection device 404 is used to detect the pH value of the material in the carbon dioxide micro-nano bubble generating device 403, thereby adjusting the pH to accelerate the generation of carbon dioxide micro-nano bubbles.

[0035] In the desulfurized gypsum calcium recycling system of the present invention, in order to improve the conversion efficiency of calcium sulfate to the target product calcium carbonate, the gypsum reaction device 101 and the carbon dioxide micro-nano bubble generating device 403 are preferably connected through the first pipeline and the fourth pipeline connected to the first circulation pump 402, and the first pipeline and the fourth pipeline connected to the first circulation pump 402 are preferably used to transport the materials in the gypsum reaction device 101 to the carbon dioxide micro-nano bubble generating device 403. The gypsum reaction device 101 and the carbon dioxide micro-nano bubble generating device 403 can also be connected through the second pipeline and the fifth pipeline connected to the second circulation pump 405, and the second pipeline and the fifth pipeline connected to the second circulation pump 405 can be used to transport the materials in the carbon dioxide micro-nano bubble generating device 403 to the gypsum reaction device 101.

[0036] In the desulfurized gypsum calcium recycling system of the present invention, in order to reduce the loss of raw materials, the ammonia water unit 5 preferably also includes an ammonia water pump 501 and a second stirring device 504, wherein the ammonia water pump 501 is used to pump part of the material in the ammonia water storage tank 505 into the gypsum reaction unit 1 through the third pipeline and / or return another part of the material in the ammonia water storage tank 505 to the ammonia water storage tank 505; the second stirring device 504 is used to stir the material in the ammonia water storage tank 505.

[0037] In the desulfurized gypsum calcium recycling system of the present invention, the ammonia water unit 5 may further include a circulation valve 502 and a second pH detection device 503. The circulation valve 502 is arranged on the third pipeline. The circulation valve 502 may be used to control the return of another part of the material in the ammonia water storage tank 505 to the ammonia water storage tank 505. The second pH detection device 503 is used to detect the pH value of the material in the ammonia water storage tank 505, thereby adjusting the pH to accelerate the reaction rate of ammonia water and carbon dioxide.

[0038] In some embodiments, the gypsum delivery pipeline for supplying gypsum to the gypsum reaction unit 1 may be provided with a gypsum quantitative feeding device 302 , and the gypsum quantitative feeding device 302 may be used to control the content of gypsum supplied to the gypsum reaction unit 1 .

[0039] In other embodiments, the gypsum conveying pipeline for supplying gypsum to the gypsum reaction unit 1 and the ammonia water unit 5 may be provided with a gypsum quantitative feeding device 302, and the gypsum quantitative feeding device 302 may be used to control the content of gypsum supplied to the gypsum reaction unit 1 and the ammonia water unit 5.

[0040] In the desulfurized calcium gypsum recycling system of the present invention, in order to meet the exhaust gas emission standards, the system preferably further includes an exhaust gas purification unit 2, and the exhaust gas purification unit 2 is preferably used to absorb the exhaust gas discharged from the gypsum reaction unit 1. The exhaust gas purification unit 2 may include a spray device 201 and a purification liquid circulation device 202. The spray device 201 can be used to absorb the gas phase in the gypsum reaction device 101. The purification liquid circulation device 202 can be used to return the material in the exhaust gas purification unit 2 to the spray device 201.

[0041] In some embodiments, Figure 1As shown, the desulfurized gypsum calcium recycling system of the present invention comprises: a gypsum reaction unit 1, a tail gas purification unit 2, a gypsum storage unit 3, a carbon dioxide micro-nano bubble generation unit 4 and an ammonia water unit 5, wherein the gypsum storage unit 3 comprises a gypsum storage device 301 and a gypsum delivery pipeline capable of supplying gypsum to the gypsum reaction unit 1 and the ammonia water unit 5 respectively; the gypsum delivery pipeline supplying gypsum to the gypsum reaction unit 1 and the ammonia water unit 5 is provided with a gypsum quantitative feeding device 302, and the gypsum quantitative feeding device 302 is used to control the content of gypsum supplied to the gypsum reaction unit 1 and the ammonia water unit 5. The carbon dioxide micro-nano bubble generating unit 4 comprises a carbon dioxide storage device 401, a carbon dioxide micro-nano bubble generating device 403 and a first pH detecting device 404; the first pH detecting device 404 is used to detect the pH value of the material in the carbon dioxide micro-nano bubble generating device 403; the gypsum reaction device 101 is connected to the carbon dioxide micro-nano bubble generating device 403 through a first pipeline and a fourth pipeline connected to the first circulating pump 402, and the first pipeline and the fourth pipeline provided with the first circulating pump 402 are used to transport the material in the gypsum reaction device 101 to the The carbon dioxide micro-nano bubble generating device 403 is in the carbon dioxide micro-nano bubble generating device 403; the gypsum reaction device 101 is also connected to the carbon dioxide micro-nano bubble generating device 403 through the second pipeline and the fifth pipeline provided with the second circulation pump 405, and the second pipeline provided with the second circulation pump 405 and the fifth pipeline are used to transport the materials in the carbon dioxide micro-nano bubble generating device 403 to the gypsum reaction device 101; the ammonia water unit 5 includes an ammonia water storage tank 505 and a third pipeline for transporting materials to the gypsum reaction unit 1; the ammonia water storage tank 505 and the carbon dioxide micro-nano bubble generating device 4 03 are connected through a first pipeline provided with a first circulation pump 402 and a second pipeline provided with a second circulation pump 405, so that the ammonia water storage tank 505 can transport materials to the carbon dioxide micro-nano bubble generating device 403 through the first pipeline, and the carbon dioxide micro-nano bubble generating device 403 can transport materials to the ammonia water storage tank 505 through the second pipeline; in the carbon dioxide micro-nano bubble generating device 403, the carbon dioxide gas from the carbon dioxide storage device 401 is mixed with the material injected through the first pipeline to form a fluid with carbon dioxide micro- or nano-bubbles.The gypsum reaction unit 1 comprises a gypsum reaction device 101, a first stirring device 102, a slurry clear liquid circulation device 103, a pH monitoring device 104, a slurry outlet 105, a slurry liquid-solid separation device 106, a solid-liquid separation device 107 and a demisting device 108. The gypsum reaction device 101 is used to react the material obtained by the treatment of the ammonia water unit 5 with gypsum to obtain slurry; the first stirring device 102 is used to stir the material in the gypsum reaction device 101; the slurry obtained by the treatment of the gypsum reaction device 101 enters the slurry liquid-solid separation device through the slurry outlet 105. 106 is used for solid-liquid separation, and part of the liquid phase processed by the slurry liquid-solid separation device 106 enters the gypsum reaction device 101 through the slurry clear liquid circulation device 103; part of the liquid phase processed by the slurry liquid-solid separation device 106 is discharged; the solid phase processed by the slurry liquid-solid separation device 106 enters the solid-liquid separation device 107 for further solid-liquid separation; the pH monitoring device 104 is used to monitor the pH value of the material in the gypsum reaction device 101; the demisting device 108 is used to remove the mist and entrained liquid phase in the gas phase in the gypsum reaction device 101. The ammonia water unit 5 may also include an ammonia water pump 501, a circulation valve 502, a second pH detection device 503 and a second stirring device 504. The ammonia water pump 501 is used to pump part of the material in the ammonia water storage tank 505 into the gypsum reaction unit 1 through the third pipeline and / or return another part of the material in the ammonia water storage tank 505 to the ammonia water storage tank 505; the circulation valve 502 is arranged on the third pipeline; the circulation valve 502 is used to control the return of another part of the material in the ammonia water storage tank 505 to the ammonia water storage tank 505; the second pH detection device 503 is used to detect the pH value of the material in the ammonia water storage tank 505; the second stirring device 504 is used to stir the material in the ammonia water storage tank 505. The tail gas purification unit 2 includes a spray device 201 and a purification liquid circulation device 202. The spray device 201 is used to absorb the gas phase in the gypsum reaction device 101. The purification liquid circulation device 202 is used to return the material in the tail gas purification unit 2 to the spraying device 201 .

[0042] The present invention also provides a desulfurized calcium gypsum recycling method, which is carried out in the above-mentioned desulfurized calcium gypsum recycling system, and the method comprises the following steps:

[0043] (1) In the carbon dioxide micro-nano bubble generating device 403, the carbon dioxide gas from the carbon dioxide storage device 401 is mixed with the material injected through the first pipeline to form a fluid with carbon dioxide micro- or nano-bubbles;

[0044] (2) introducing the gypsum in the gypsum storage unit 3 into the gypsum reaction unit 1, introducing the material in the ammonia water unit 5 into the carbon dioxide micro-nano bubble generating unit 4 through the first pipeline provided with the first circulation pump 402 for reaction, and then introducing the material in the carbon dioxide micro-nano bubble generating unit 4 into the ammonia water unit 5 through the second pipeline provided with the second circulation pump 405 for reaction; then introducing part of the material in the ammonia water unit 5 into the gypsum reaction unit 1 through the third pipeline to react with gypsum to generate calcium carbonate; or The gypsum in the gypsum storage unit 3 is introduced into the ammonia water unit 5 and the gypsum reaction unit 1, and then the material in the ammonia water unit 5 is introduced into the carbon dioxide micro-nano bubble generating unit 4 through the first pipeline provided with the first circulation pump 402 for reaction, and then the material in the carbon dioxide micro-nano bubble generating unit 4 is introduced into the ammonia water unit 5 through the second pipeline provided with the second circulation pump 405 for reaction; and then part of the material in the ammonia water unit 5 is introduced into the gypsum reaction unit 1 through the third pipeline to react with gypsum to generate calcium carbonate.

[0045] According to the method of the present invention, the reaction of carbon dioxide with ammonia water or ammonia water gypsum mixed slurry is accelerated by micro-nano carbon dioxide bubbles, the material consumption of carbon dioxide is reduced, and the ammonia escape is reduced; by forming a two-step reaction of ammonia water and carbon dioxide to form ammonium carbonate and ammonium carbonate and calcium sulfate to form calcium carbonate, and controlling the pH value in each unit respectively, the reaction efficiency is accelerated. Moreover, the reaction of micro-nano carbon dioxide bubbles with ammonia water gypsum mixed slurry reduces the concentration of ammonium carbonate, which is conducive to the positive reaction of carbon dioxide and ammonia water.

[0046] In the method of the present invention, in the carbon dioxide micro-nano bubble generating unit 4, the reaction of ammonia water and carbon dioxide is carried out according to reaction equation 1:

[0047] Reaction equation 1: 2NH3·H2O+CO2→(NH4)2CO3+H2O.

[0048] In the method of the present invention, in the gypsum reaction unit 1, the reaction of ammonium carbonate and calcium sulfate is carried out according to reaction equation 2:

[0049] Reaction equation 2: CaSO4·2H2O+(NH4)2CO3→CaCO3+(NH4)2SO4+2H2O.

[0050] In the method of the present invention, in order to reduce the loss of raw materials, the method also preferably includes: returning another part of the material in the ammonia water unit 5 to the ammonia water unit 5. Specifically, the process of returning another part of the material in the ammonia water unit 5 to the ammonia water unit 5 may include: returning another part of the material in the ammonia water storage tank 505 to the ammonia water storage tank 505 through the third pipeline provided with the circulation valve 502 and the ammonia water pump 501, stirring the material in the ammonia water storage tank 505 through the second stirring device 504, and detecting the pH value of the material in the ammonia water storage tank 505 through the second pH detection device 503, thereby adjusting the pH to accelerate the reaction rate of ammonia water and carbon dioxide. The pH value of the material in the ammonia water storage tank 505 may be 7.5-11.7. In some embodiments, when the material in the ammonia water storage tank 505 is ammonia water, the pH value of the material in the ammonia water storage tank 505 is 9.5-11.7. In some embodiments, when the material in the ammonia water storage tank 505 is a mixed slurry of ammonia water and gypsum, the pH value of the material in the ammonia water storage tank 505 is 7.5-10.5, and the solid content of the material in the ammonia water storage tank 505 is 5%-10%.

[0051] In the method of the present invention, in the process of passing part of the material in the ammonia water unit 5 through the third pipeline into the gypsum reaction unit 1 to react with gypsum to generate calcium carbonate and returning another part of the material in the ammonia water unit 5 to the ammonia water unit 5, the mass ratio of the part of the material in the ammonia water unit 5 to the other part of the material in the ammonia water unit 5 can be (0.5-99): 1, preferably (1-99): 1. In the process of passing the gypsum in the gypsum storage unit 3 into the ammonia water unit 5 and the gypsum reaction unit 1, the mass ratio of the gypsum passed into the ammonia water unit 5 to the gypsum passed into the gypsum reaction unit 1 can be (0-2): 1, preferably (0-0.5): 1.

[0052] In the method of the present invention, in order to meet the exhaust emission standards, the method preferably further includes: passing the exhaust gas discharged through the gypsum reaction unit 1 into the exhaust gas purification unit 2 for absorption. Specifically, the process of passing the exhaust gas discharged through the gypsum reaction unit 1 into the exhaust gas purification unit 2 for absorption may include: the gas phase in the gypsum reaction device 101 enters the demisting device 108 to remove the mist and the entrained liquid phase in the gas phase, and then the gas phase is absorbed by the spraying device 201, and the material in the exhaust gas purification unit 2 is returned to the spraying device 201 through the purification liquid circulation device 202. The spraying device 201 absorbs ammonia by spraying water or gypsum slurry. The gypsum slurry contains calcium sulfate, water and carbon dioxide.

[0053] In the method of the present invention, in order to reduce the loss of raw materials, the method preferably further comprises: in the gypsum reaction unit 1, the slurry discharged from the gypsum reaction device 101 is transported to the slurry liquid-solid separation device 106 through the slurry outlet 105 for solid-liquid separation, and part or all of the liquid phase obtained by the treatment of the slurry liquid-solid separation device 106 enters the gypsum reaction device 101 through the slurry clear liquid circulation device 103; the solid phase obtained by the treatment of the slurry liquid-solid separation device 106 is transported to the solid-liquid separation device 107 for further solid-liquid separation to obtain and recover calcium carbonate solid. In some embodiments, part of the liquid phase obtained by the treatment of the slurry liquid-solid separation device 106 enters the gypsum reaction device 101 through the slurry clear liquid circulation device 103; another part of the liquid phase obtained by the treatment of the slurry liquid-solid separation device 106 is discharged. The mass ratio of a portion of the liquid phase obtained by the slurry liquid-solid separation device 106 to another portion of the liquid phase obtained by the slurry liquid-solid separation device 106 can be (1-4):1, preferably (2-3):1.

[0054] In the method of the present invention, the method may further include: stirring the material in the gypsum reaction device 101 by the first stirring device 102; and monitoring the pH value of the material in the gypsum reaction device 101 by the pH monitoring device 104. The pH value of the material in the gypsum reaction device 101 may be 7.5-9.5, preferably 8-9.

[0055] In the method of the present invention, in order to improve the conversion efficiency of calcium sulfate to the target product calcium carbonate, the method also preferably includes: transporting the material discharged from the gypsum reaction device 101 to the carbon dioxide micro-nano bubble generating device 403 through the first circulation pump 402. The method may also include: transporting the material in the carbon dioxide micro-nano bubble generating device 403 to the gypsum reaction device 101 through the second circulation pump 405. In some embodiments, the method includes: transporting the material in the gypsum reaction device 101 to the carbon dioxide micro-nano bubble generating device 403 through the first pipeline provided with the first circulation pump 402 and the fourth pipeline; transporting the material in the carbon dioxide micro-nano bubble generating device 403 to the gypsum reaction device 101 through the second pipeline provided with the second circulation pump 405 and the fifth pipeline.

[0056] In the method of the present invention, the method may further include: in the carbon dioxide micro-nano bubble generating unit 4, detecting the pH value of the material in the carbon dioxide micro-nano bubble generating device 403 by the first pH detecting device 404. The pH value of the material in the carbon dioxide micro-nano bubble generating device 403 is 6-10.5. In some embodiments, when the material in the carbon dioxide micro-nano bubble generating device 403 is carbon dioxide micro-nano bubbles, ammonia water, ammonium carbonate and ammonium bicarbonate, the pH value of the material in the carbon dioxide micro-nano bubble generating device 403 is 6-9. In other embodiments, when the material in the carbon dioxide micro-nano bubble generating device 403 is a mixed slurry of carbon dioxide, ammonia water and gypsum, the pH value of the material in the carbon dioxide micro-nano bubble generating device 403 is 7.5-10.5, and the solid content of the material in the carbon dioxide micro-nano bubble generating device 403 is 3%-8%.

[0057] In the method described in the present invention, when the materials in the carbon dioxide micro-nano bubble generating device 403 are ammonia water, carbon dioxide, ammonium carbonate and ammonium bicarbonate and optional gypsum, the materials in the carbon dioxide micro-nano bubble generating device 403 are formed into a high-speed fluid, and carbon dioxide is sheared to form carbon dioxide micro-nano bubbles. The particle size of the carbon dioxide micro-nano bubbles is 100 nanometers to 100 micrometers, and the residence time in ammonia water is less than 10 seconds to fully dissolve, and the residence time in a mixed slurry of ammonia water and gypsum is less than 8 seconds to fully dissolve. Compared with the millimeter-level bubbles produced by conventional aeration in the field, the carbon dioxide micro-nano bubbles have a higher dissolution rate and a smaller particle size.

[0058] In the method of the present invention, the gas in the carbon dioxide storage device 401 can be clean flue gas containing carbon dioxide, and the volume concentration of carbon dioxide can be above 10%, preferably 10%-20%. The clean flue gas can be the flue gas after denitration, desulfurization and dust removal in a power plant.

[0059] In some embodiments, the specific process of passing the gypsum in the gypsum storage unit 3 into the gypsum reaction unit 1 may be passing the gypsum in the gypsum storage device 301 into the gypsum reaction unit 1 through the gypsum quantitative feeding device 302, and controlling the content of the gypsum supplied to the gypsum reaction unit 1 through the gypsum quantitative feeding device 302.

[0060] In other embodiments, the specific process of passing the gypsum in the gypsum storage unit 3 into the ammonia water unit 5 and the gypsum reaction unit 1 may be to transport the gypsum in the gypsum storage device 301 to the ammonia water unit 5 and the gypsum reaction unit 1 through the gypsum quantitative feeding device 302, and to control the content of gypsum supplied to the gypsum reaction unit 1 and the ammonia water unit 5 through the gypsum quantitative feeding device 302.

[0061] In some embodiments, the present invention further provides a desulfurized calcium gypsum recycling method, which is carried out in the above-mentioned desulfurized calcium gypsum recycling system, and the method comprises the following steps:

[0062] (1) In the carbon dioxide micro-nano bubble generating device 403, the carbon dioxide gas from the carbon dioxide storage device 401 is mixed with the material injected through the first pipeline provided with the first circulation pump 402 to form a fluid with carbon dioxide micro- or nano-bubbles;

[0063] (2) The gypsum in the gypsum storage device 301 is introduced into the gypsum reaction device 101 through the gypsum quantitative feeding device 302, and the content of the gypsum supplied to the gypsum reaction device 101 is controlled by the gypsum quantitative feeding device 302; the material in the ammonia water storage tank 505 is introduced into the carbon dioxide micro-nano bubble generating device 403 through the first pipeline provided with the first circulation pump 402 for reaction, and then the material in the carbon dioxide micro-nano bubble generating device 403 is passed through the first pipeline provided with the second circulation pump 405. The second pipeline is passed into the ammonia water storage tank 505 for reaction; then part of the material in the ammonia water storage tank 505 is passed into the gypsum reaction device 101 through the third pipeline to react with gypsum to generate calcium carbonate; the first stirring device 102 is used to stir the material in the gypsum reaction device 101; the pH value of the material in the gypsum reaction device 101 is monitored by the pH monitoring device 104; the slurry discharged from the gypsum reaction device 101 is transported to the slurry liquid-solid separation device 106 through the slurry outlet 105 for solidification; Liquid separation, part of the liquid phase treated by the slurry liquid-solid separation device 106 enters the gypsum reaction device 101 through the slurry clear liquid circulation device 103; another part of the liquid phase treated by the slurry liquid-solid separation device 106 is discharged; the solid phase treated by the slurry liquid-solid separation device 106 is transported to the solid-liquid separation device 107 for further solid-liquid separation to obtain calcium carbonate solid and recover it; the gas phase in the gypsum reaction device 101 enters the demisting device 108 to remove the mist and entrained liquid phase in the gas phase, and then passes through the The spraying device 201 sprays water or gypsum slurry to absorb the gas phase, and returns the material in the tail gas purification unit 2 to the spraying device 201 through the purified liquid circulation device 202; another part of the material in the ammonia storage tank 505 is returned to the ammonia storage tank 505 through the third pipeline provided with the circulation valve 502 and the ammonia pump 501, and the material in the ammonia storage tank 505 is stirred by the second stirring device 504, and the pH value of the material in the ammonia storage tank 505 is detected by the second pH detection device 503;

[0064] (3) The material in the gypsum reaction device 101 is transported to the carbon dioxide micro-nano bubble generating device 403 through the first pipeline provided with the first circulation pump 402 and the fourth pipeline; the material in the carbon dioxide micro-nano bubble generating device 403 is transported to the gypsum reaction device 101 through the second pipeline provided with the second circulation pump 405 and the fifth pipeline; the pH value of the material in the carbon dioxide micro-nano bubble generating device 403 is detected by the first pH detecting device 404.

[0065] In other embodiments, the present invention further provides a method for recycling desulfurized calcium gypsum, which is carried out in the above-mentioned desulfurized calcium gypsum recycling system, and the method comprises the following steps:

[0066] (1) In the carbon dioxide micro-nano bubble generating device 403, the carbon dioxide gas from the carbon dioxide storage device 401 is mixed with the material injected through the first pipeline provided with the first circulation pump 402 to form a fluid with carbon dioxide micro- or nano-bubbles;

[0067] (2) The gypsum in the gypsum storage device 301 is introduced into the gypsum reaction device 101 and the carbon dioxide micro-nano bubble generating device 403 through the gypsum quantitative feeding device 302, and the content of the gypsum supplied to the gypsum reaction device 101 and the carbon dioxide micro-nano bubble generating device 403 is controlled by the gypsum quantitative feeding device 302. Then, the material in the ammonia water storage tank 505 is introduced into the carbon dioxide micro-nano bubble generating device 403 through a first pipeline provided with a first circulation pump 402 for reaction. Then, the carbon dioxide micro-nano bubble generating device 403 is The material in the production device 403 is passed into the ammonia storage tank 505 through the second pipeline provided with the second circulation pump 405 for reaction; then part of the material in the ammonia storage tank 505 is passed into the gypsum reaction device 101 through the third pipeline to react with gypsum to generate calcium carbonate, and the first stirring device 102 is used to stir the material in the gypsum reaction device 101; the pH value of the material in the gypsum reaction device 101 is monitored by the pH monitoring device 104; the slurry discharged from the gypsum reaction device 101 is transported to the slurry outlet 105. The slurry liquid-solid separation device 106 performs solid-liquid separation, and part of the liquid phase obtained by the treatment of the slurry liquid-solid separation device 106 enters the gypsum reaction device 101 through the slurry clear liquid circulation device 103; another part of the liquid phase obtained by the treatment of the slurry liquid-solid separation device 106 is discharged; the solid phase obtained by the treatment of the slurry liquid-solid separation device 106 is transported to the solid-liquid separation device 107 for further solid-liquid separation to obtain and recover calcium carbonate solid; the gas phase in the gypsum reaction device 101 enters the demisting device 108 to remove the mist and entrained liquid in the gas phase. phase, and then spraying water or gypsum slurry through the spraying device 201 to absorb the gas phase, and returning the material in the tail gas purification unit 2 to the spraying device 201 through the purified liquid circulation device 202; returning another part of the material in the ammonia water storage tank 505 to the ammonia water storage tank 505 through the third pipeline provided with the circulation valve 502 and the ammonia water pump 501, and stirring the material in the ammonia water storage tank 505 through the second stirring device 504, and detecting the pH value of the material in the ammonia water storage tank 505 through the second pH detection device 503;

[0068] (3) The material in the gypsum reaction device 101 is transported to the carbon dioxide micro-nano bubble generating device 403 through the first pipeline provided with the first circulation pump 402 and the fourth pipeline; the material in the carbon dioxide micro-nano bubble generating device 403 is transported to the gypsum reaction device 101 through the second pipeline provided with the second circulation pump 405 and the fifth pipeline; the pH value of the material in the carbon dioxide micro-nano bubble generating device 403 is detected by the first pH detecting device 404.

[0069] The following examples further illustrate the desulfurized gypsum calcium recycling system and method of the present invention. The examples are implemented based on the technical solution of the present invention, and provide detailed implementation methods and specific operation processes, but the protection scope of the present invention is not limited to the following examples.

[0070] The experimental methods in the following examples, unless otherwise specified, are all conventional methods in the art. The experimental materials used in the following examples, unless otherwise specified, are all commercially available.

[0071] In the embodiment, the process of recycling desulfurized gypsum calcium is as follows Figure 1The desulfurized gypsum calcium recycling system shown in the figure comprises: a gypsum reaction unit 1, a tail gas purification unit 2, a gypsum storage unit 3, a carbon dioxide micro-nano bubble generating unit 4 and an ammonia water unit 5, wherein the gypsum storage unit 3 comprises a gypsum storage device 301 and a gypsum conveying pipeline capable of supplying gypsum to the gypsum reaction unit 1 and the ammonia water unit 5 respectively; the gypsum conveying pipeline supplying gypsum to the gypsum reaction unit 1 and the ammonia water unit 5 is provided with a gypsum quantitative feeding device 302, and the gypsum quantitative feeding device 302 is used to control the gypsum supplied to the gypsum reaction unit 1 and the ammonia water unit 5. The carbon dioxide micro-nano bubble generating unit 4 comprises a carbon dioxide storage device 401, a carbon dioxide micro-nano bubble generating device 403 and a first pH detecting device 404; the first pH detecting device 404 is used to detect the pH value of the material in the carbon dioxide micro-nano bubble generating device 403; the gypsum reaction device 101 is connected to the carbon dioxide micro-nano bubble generating device 403 through a first pipeline and a fourth pipeline connected to the first circulating pump 402, and the first pipeline and the fourth pipeline provided with the first circulating pump 402 are used to transport the material in the gypsum reaction device 101 to the The carbon dioxide micro-nano bubble generating device 403 is in the carbon dioxide micro-nano bubble generating device 403; the gypsum reaction device 101 is also connected to the carbon dioxide micro-nano bubble generating device 403 through the second pipeline and the fifth pipeline provided with the second circulation pump 405, and the second pipeline provided with the second circulation pump 405 and the fifth pipeline are used to transport the materials in the carbon dioxide micro-nano bubble generating device 403 to the gypsum reaction device 101; the ammonia water unit 5 includes an ammonia water storage tank 505 and a third pipeline for transporting materials to the gypsum reaction unit 1; the ammonia water storage tank 505 and the carbon dioxide micro-nano bubble generating device 4 03 are connected through a first pipeline provided with a first circulation pump 402 and a second pipeline provided with a second circulation pump 405, so that the ammonia water storage tank 505 can transport materials to the carbon dioxide micro-nano bubble generating device 403 through the first pipeline, and the carbon dioxide micro-nano bubble generating device 403 can transport materials to the ammonia water storage tank 505 through the second pipeline; in the carbon dioxide micro-nano bubble generating device 403, the carbon dioxide gas from the carbon dioxide storage device 401 is mixed with the material injected through the first pipeline to form a fluid with carbon dioxide micro- or nano-bubbles.The gypsum reaction unit 1 comprises a gypsum reaction device 101, a first stirring device 102, a slurry clear liquid circulation device 103, a pH monitoring device 104, a slurry outlet 105, a slurry liquid-solid separation device 106, a solid-liquid separation device 107 and a demisting device 108. The gypsum reaction device 101 is used to react the material obtained by the treatment of the ammonia water unit 5 with gypsum to obtain slurry; the first stirring device 102 is used to stir the material in the gypsum reaction device 101; the slurry obtained by the treatment of the gypsum reaction device 101 enters the slurry liquid-solid separation device 106 through the slurry outlet 105. 06 for solid-liquid separation, part of the liquid phase processed by the slurry liquid-solid separation device 106 enters the gypsum reaction device 101 through the slurry clear liquid circulation device 103; the other part of the liquid phase processed by the slurry liquid-solid separation device 106 is discharged; the solid phase processed by the slurry liquid-solid separation device 106 enters the solid-liquid separation device 107 for further solid-liquid separation; the pH monitoring device 104 is used to monitor the pH value of the material in the gypsum reaction device 101; the demisting device 108 is used to remove the mist and entrained liquid phase in the gas phase in the gypsum reaction device 101. The ammonia water unit 5 may also include an ammonia water pump 501, a circulation valve 502, a second pH detection device 503 and a second stirring device 504. The ammonia water pump 501 is used to pump part of the material in the ammonia water storage tank 505 into the gypsum reaction unit 1 through the third pipeline and / or return another part of the material in the ammonia water storage tank 505 to the ammonia water storage tank 505; the circulation valve 502 is arranged on the third pipeline; the circulation valve 502 is used to control the return of another part of the material in the ammonia water storage tank 505 to the ammonia water storage tank 505; the second pH detection device 503 is used to detect the pH value of the material in the ammonia water storage tank 505; the second stirring device 504 is used to stir the material in the ammonia water storage tank 505. The tail gas purification unit 2 includes a spray device 201 and a purification liquid circulation device 202. The spray device 201 is used to absorb the gas phase in the gypsum reaction device 101. The purification liquid circulation device 202 is used to return the material in the tail gas purification unit 2 to the spraying device 201 .

[0072] Example 1

[0073] (1) In the carbon dioxide micro-nano bubble generating device 403, the gas from the carbon dioxide storage device 401 (the gas is clean flue gas containing carbon dioxide gas, the volume concentration of carbon dioxide is 15%, and the clean flue gas is the flue gas after denitration, desulfurization and dust removal in the power plant) is mixed with the material injected through the first pipeline provided with the first circulation pump 402 to form a fluid with carbon dioxide micro- or nano-bubbles;

[0074] (2) The gypsum in the gypsum storage device 301 is introduced into the gypsum reaction device 101 through the gypsum quantitative feeding device 302, and the content of the gypsum supplied to the gypsum reaction device 101 is controlled by the gypsum quantitative feeding device 302; the material in the ammonia storage tank 505 is introduced into the carbon dioxide micro-nano bubble generating device 403 through the first pipeline provided with the first circulation pump 402 for reaction, and then the material in the carbon dioxide micro-nano bubble generating device 403 is introduced into the ammonia storage tank 505 through the second pipeline provided with the second circulation pump 405 for reaction, and the unreacted carbon dioxide micro-nano bubbles continue to react with the ammonia storage tank 505. The ammonia solution continues to react fully to ensure that all carbon dioxide is absorbed; then part of the material in the ammonia solution storage tank 505 is introduced into the gypsum reaction device 101 through the third pipeline to react with gypsum to generate calcium carbonate; the first stirring device 102 is used to stir the material in the gypsum reaction device 101; the pH value of the material in the gypsum reaction device 101 is monitored by the pH monitoring device 104, and the pH value is 8-9; the slurry discharged from the gypsum reaction device 101 is transported to the slurry liquid-solid separation device 106 through the slurry outlet 105 for solid-liquid separation, and part of the liquid phase obtained by the treatment of the slurry liquid-solid separation device 106 is passed through the slurry clear liquid circulation device 1 03 enters the gypsum reaction device 101; another part of the liquid phase treated by the slurry liquid-solid separation device 106 is discharged; the mass ratio of the part of the liquid phase treated by the slurry liquid-solid separation device 106 and the other part of the liquid phase treated by the slurry liquid-solid separation device 106 is 2:1; the solid phase treated by the slurry liquid-solid separation device 106 is transported to the solid-liquid separation device 107 for further solid-liquid separation to obtain calcium carbonate solid and recover it; the gas phase in the gypsum reaction device 101 enters the demisting device 108 to remove the mist and entrained liquid phase in the gas phase, and then the gas phase is absorbed by spraying water or gypsum slurry through the spraying device 201 to remove the tail gas The material in the purification unit 2 is returned to the spraying device 201 through the purification liquid circulation device 202; another part of the material in the ammonia water storage tank 505 is returned to the ammonia water storage tank 505 through the third pipeline provided with the circulation valve 502 and the ammonia water pump 501 (the mass ratio of the part of the material in the ammonia water storage tank 505 to the other part of the material in the ammonia water storage tank 505 is 3:1), and the material in the ammonia water storage tank 505 is stirred by the second stirring device 504, and the pH value of the material in the ammonia water storage tank 505 is detected by the second pH detection device 503; when the material in the ammonia water storage tank 505 is only ammonia water, the pH value is 10.5-111;

[0075] (3) The material in the gypsum reaction device 101 is transported to the carbon dioxide micro-nano bubble generating device 403 through the first pipeline provided with the first circulation pump 402 and the fourth pipeline; the material in the carbon dioxide micro-nano bubble generating device 403 is transported to the gypsum reaction device 101 through the second pipeline provided with the second circulation pump 405 and the fifth pipeline; the pH value of the material in the carbon dioxide micro-nano bubble generating device 403 is detected by the first pH detecting device 404; when the material in the carbon dioxide micro-nano bubble generating device 403 is a mixed solution of ammonia water, carbon dioxide micro-nano bubbles, ammonium carbonate and ammonium bicarbonate, the pH value is 7-8.

[0076] Example 2

[0077] (1) In the carbon dioxide micro-nano bubble generating device 403, the gas from the carbon dioxide storage device 401 (the gas is clean flue gas containing carbon dioxide gas, the volume concentration of carbon dioxide is 10%, and the clean flue gas is the flue gas after denitration, desulfurization and dust removal in the power plant) is mixed with the material injected through the first pipeline provided with the first circulation pump 402 to form a fluid with carbon dioxide micro- or nano-bubbles;

[0078] (2) The gypsum in the gypsum storage device 301 is introduced into the gypsum reaction device 101 and the carbon dioxide micro-nano bubble generating device 403 through the gypsum quantitative feeding device 302, and the content of gypsum supplied to the gypsum reaction device 101 and the carbon dioxide micro-nano bubble generating device 403 is controlled by the gypsum quantitative feeding device 302 (the mass ratio of the gypsum introduced into the ammonia water unit 5 to the gypsum introduced into the gypsum reaction unit 1 is 0.08:1), then the material in the ammonia storage tank 505 is introduced into the carbon dioxide micro-nano bubble generating device 403 through the first pipeline provided with the first circulation pump 402 for reaction, and then the material in the carbon dioxide micro-nano bubble generating device 403 is introduced into the ammonia storage tank 505 through the second pipeline provided with the second circulation pump 405 for reaction, and the unreacted carbon dioxide micro-nano bubbles continue to fully react with the ammonia in the ammonia storage tank 505 to ensure that all the carbon dioxide is absorbed; then part of the material in the ammonia storage tank 505 is introduced into the gypsum reaction device 101 through the third pipeline to react with gypsum to generate carbonic acid The first stirring device 102 is used to stir the material in the gypsum reaction device 101; the pH value of the material in the gypsum reaction device 101 is monitored by the pH monitoring device 104, and the pH value is 8-9; the slurry discharged from the gypsum reaction device 101 is transported to the slurry liquid-solid separation device 106 through the slurry outlet 105 for solid-liquid separation, and part of the liquid phase processed by the slurry liquid-solid separation device 106 enters the gypsum reaction device 101 through the slurry clear liquid circulation device 103; another part of the liquid phase processed by the slurry liquid-solid separation device 106 is discharged; after the slurry liquid-solid separation device 106 is discharged, ... The mass ratio of a part of the liquid phase processed by the separation device 106 and another part of the liquid phase processed by the slurry liquid-solid separation device 106 is 4:1; the solid phase processed by the slurry liquid-solid separation device 106 is transported to the solid-liquid separation device 107 for further solid-liquid separation to obtain calcium carbonate solid and recover it; the gas phase in the gypsum reaction device 101 enters the demisting device 108 to remove the mist and the entrained liquid phase in the gas phase, and then the gas phase is sprayed with water or gypsum slurry through the spraying device 201 to absorb the gas phase, and the material in the tail gas purification unit 2 is returned to the spraying device 201 through the purification liquid circulation device 202; Another part of the material in the ammonia storage tank 505 is returned to the ammonia storage tank 505 through the third pipeline provided with the circulation valve 502 and the ammonia pump 501 (the mass ratio of the part of the material in the ammonia storage tank 505 to the other part of the material in the ammonia storage tank 505 is 10:1), and the material in the ammonia storage tank 505 is stirred by the second stirring device 504, and the pH value of the material in the ammonia storage tank 505 is detected by the second pH detection device 503; when the material in the ammonia storage tank 505 is a mixed slurry of ammonia water and gypsum, the pH value is 8.5-10.5, and the solid content is 5%-8%;.

[0079] (3) The material in the gypsum reaction device 101 is transported to the carbon dioxide micro-nano bubble generating device 403 through the first pipeline provided with the first circulation pump 402 and the fourth pipeline; the material in the carbon dioxide micro-nano bubble generating device 403 is transported to the gypsum reaction device 101 through the second pipeline provided with the second circulation pump 405 and the fifth pipeline; the pH value of the material in the carbon dioxide micro-nano bubble generating device 403 is detected by the first pH detecting device 404; when the material in the carbon dioxide micro-nano bubble generating device 403 is a mixed solution of ammonia water, carbon dioxide micro-nano bubbles, ammonium carbonate, ammonium bicarbonate and gypsum, the pH value is 7.5-10.5, and the solid content is 3%-8%.

[0080] Example 3

[0081] (1) In the carbon dioxide micro-nano bubble generating device 403, the gas from the carbon dioxide storage device 401 (the gas is clean flue gas containing carbon dioxide gas, the volume concentration of carbon dioxide is 15%, and the clean flue gas is the flue gas after denitration, desulfurization and dust removal in the power plant) is mixed with the material injected through the first pipeline provided with the first circulation pump 402 to form a fluid with carbon dioxide micro- or nano-bubbles;

[0082] (2) The gypsum in the gypsum storage device 301 is introduced into the gypsum reaction device 101 and the carbon dioxide micro-nano bubble generating device 403 through the gypsum quantitative feeding device 302, and the content of gypsum supplied to the gypsum reaction device 101 and the carbon dioxide micro-nano bubble generating device 403 is controlled by the gypsum quantitative feeding device 302 (the mass ratio of the gypsum introduced into the ammonia water unit 5 to the gypsum introduced into the gypsum reaction unit 1 is 0.08:1), then the material in the ammonia storage tank 505 is introduced into the carbon dioxide micro-nano bubble generating device 403 through the first pipeline provided with the first circulation pump 402 for reaction, and then the material in the carbon dioxide micro-nano bubble generating device 403 is introduced into the ammonia storage tank 505 through the second pipeline provided with the second circulation pump 405 for reaction, and the unreacted carbon dioxide micro-nano bubbles continue to fully react with the ammonia in the ammonia storage tank 505 to ensure that all the carbon dioxide is absorbed; then part of the material in the ammonia storage tank 505 is introduced into the gypsum reaction device 101 through the third pipeline to react with gypsum to generate carbon dioxide. The first stirring device 102 is used to stir the material in the gypsum reaction device 101; the pH value of the material in the gypsum reaction device 101 is monitored by the pH monitoring device 104, and the pH value is 8-9; the slurry discharged from the gypsum reaction device 101 is transported to the slurry liquid-solid separation device 106 through the slurry outlet 105 for solid-liquid separation, and part of the liquid phase processed by the slurry liquid-solid separation device 106 enters the gypsum reaction device 101 through the slurry clear liquid circulation device 103; another part of the liquid phase processed by the slurry liquid-solid separation device 106 is discharged; the slurry liquid The mass ratio of a part of the liquid phase processed by the solid separation device 106 and another part of the liquid phase processed by the slurry liquid-solid separation device 106 is 2:1; the solid phase processed by the slurry liquid-solid separation device 106 is transported to the solid-liquid separation device 107 for further solid-liquid separation to obtain and recover calcium carbonate solid; the gas phase in the gypsum reaction device 101 enters the demisting device 108 to remove the mist and the entrained liquid phase in the gas phase, and then the gas phase is sprayed with water or gypsum slurry through the spraying device 201 to absorb the gas phase, and the material in the tail gas purification unit 2 is returned to the spraying device 201 through the purification liquid circulation device 202; Another part of the material in the ammonia storage tank 505 is returned to the ammonia storage tank 505 through the third pipeline provided with the circulation valve 502 and the ammonia pump 501 (the mass ratio of the part of the material in the ammonia storage tank 505 to the other part of the material in the ammonia storage tank 505 is 3:1), and the material in the ammonia storage tank 505 is stirred by the second stirring device 504, and the pH value of the material in the ammonia storage tank 505 is detected by the second pH detection device 503; when the material in the ammonia storage tank 505 is a mixed slurry of ammonia water and gypsum, the pH value is 8.5-10.5, and the solid content is 5%-8%;.

[0083] (3) The material in the gypsum reaction device 101 is transported to the carbon dioxide micro-nano bubble generating device 403 through the first pipeline provided with the first circulation pump 402 and the fourth pipeline; the material in the carbon dioxide micro-nano bubble generating device 403 is transported to the gypsum reaction device 101 through the second pipeline provided with the second circulation pump 405 and the fifth pipeline; the pH value of the material in the carbon dioxide micro-nano bubble generating device 403 is detected by the first pH detecting device 404; when the material in the carbon dioxide micro-nano bubble generating device 403 is a mixed solution of ammonia water, carbon dioxide micro-nano bubbles, ammonium carbonate, ammonium bicarbonate and gypsum, the pH value is 7.5-10.5, and the solid content is 3%-8%.

[0084] Comparative Example 1

[0085] The method of Example 2 is implemented, except that the carbon dioxide micro-nano bubble generating device 403 is replaced by a traditional carbon dioxide bubble generating device.

[0086] Test Case

[0087] When the method described in Examples 1 and 2 and Comparative Example 1 was implemented for 1 h, 2 h, 3 h and 4 h, respectively, the purity of the prepared calcium carbonate, the conversion rate of calcium carbonate and the ammonia escape rate were measured and recorded in Table 1. The test method of the purity X of calcium carbonate refers to the national standard GB / T 21508-2008, the calculation formula of the conversion rate η of calcium carbonate (assuming that the purity of gypsum calcium sulfate is 100%) is 1.36X / (1+0.36X), and the test method of the ammonia escape rate refers to the industry standard DL / T1286-2013.

[0088] Table 1

[0089]

[0090] It can be seen from the results in Table 1 that the embodiments of the desulfurized gypsum calcium recycling system and method of the present invention have a faster reaction rate, a higher purity of calcium carbonate and a higher conversion rate of calcium carbonate, and a lower ammonia escape rate.

[0091] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A desulfurized gypsum calcium recycling system, characterized in that: The system comprises: a gypsum reaction unit (1), a gypsum storage unit (3), a carbon dioxide micro-nano bubble generation unit (4) and an ammonia water unit (5), wherein: The gypsum storage unit (3) comprises a gypsum storage device (301) and a gypsum delivery pipeline capable of supplying gypsum to the gypsum reaction unit (1) and the ammonia water unit (5) respectively; The carbon dioxide micro-nano bubble generating unit (4) comprises a carbon dioxide storage device (401) and a carbon dioxide micro-nano bubble generating device (403); The ammonia water unit (5) comprises an ammonia water storage tank (505) and a third pipeline for conveying materials to the gypsum reaction unit (1); The ammonia water storage tank (505) and the carbon dioxide micro-nano bubble generating device (403) are connected via a first pipeline provided with a first circulation pump (402) and a second pipeline provided with a second circulation pump (405), so that the ammonia water storage tank (505) can transport materials to the carbon dioxide micro-nano bubble generating device (403) through the first pipeline, and the carbon dioxide micro-nano bubble generating device (403) can transport materials to the ammonia water storage tank (505) through the second pipeline; in the carbon dioxide micro-nano bubble generating device (403), the carbon dioxide gas from the carbon dioxide storage device (401) is mixed with the material injected through the first pipeline to form a fluid with carbon dioxide micro- or nano-bubbles.

2. The desulfurized gypsum calcium recycling system according to claim 1, characterized in that: The gypsum reaction unit (1) comprises a gypsum reaction device (101), a first stirring device (102), a slurry clear liquid circulation device (103), a slurry outlet (105), a slurry liquid-solid separation device (106) and a solid-liquid separation device (107). The gypsum reaction device (101) is used to react the material obtained by the treatment of the ammonia water unit (5) with gypsum to obtain slurry; The first stirring device (102) is used to stir the materials in the gypsum reaction device (101); The slurry obtained by the treatment of the gypsum reaction device (101) enters the slurry liquid-solid separation device (106) through the slurry outlet (105) for solid-liquid separation, and part or all of the liquid phase obtained by the treatment of the slurry liquid-solid separation device (106) enters the gypsum reaction device (101) through the slurry clear liquid circulation device (103); the solid phase obtained by the treatment of the slurry liquid-solid separation device (106) enters the solid-liquid separation device (107) for further solid-liquid separation.

3. The desulfurized gypsum calcium recycling system according to claim 1 or 2, characterized in that: The ammonia water unit (5) further comprises an ammonia water pump (501), a second stirring device (504), The ammonia water pump (501) is used to pump part of the material in the ammonia water storage tank (505) into the gypsum reaction unit (1) through the third pipeline and / or return another part of the material in the ammonia water storage tank (505) to the ammonia water storage tank (505); The second stirring device (504) is used to stir the material in the ammonia water storage tank (505).

4. The desulfurized gypsum calcium recycling system according to any one of claims 1 to 3, characterized in that: The system further comprises a tail gas purification unit (2), wherein the tail gas purification unit (2) is used to absorb the tail gas discharged from the gypsum reaction unit (1).

5. A method for recycling desulfurized gypsum calcium, characterized in that: The method is carried out in the desulfurized gypsum calcium recycling system according to any one of claims 1 to 4, and the method comprises the following steps: (1) In the carbon dioxide micro-nano bubble generating device (403), the carbon dioxide gas from the carbon dioxide storage device (401) is mixed with the material injected through the first pipeline to form a fluid with carbon dioxide micro- or nano-bubbles; (2) introducing the gypsum in the gypsum storage unit (3) into the gypsum reaction unit (1), introducing the material in the ammonia water unit (5) into the carbon dioxide micro-nano bubble generating unit (4) through the first pipeline provided with the first circulation pump (402) for reaction, and then introducing the material in the carbon dioxide micro-nano bubble generating unit (4) into the ammonia water unit (5) through the second pipeline provided with the second circulation pump (405) for reaction; and then introducing part of the material in the ammonia water unit (5) into the gypsum reaction unit (1) through the third pipeline to react with the gypsum to generate calcium carbonate; or, The gypsum in the gypsum storage unit (3) is introduced into the ammonia water unit (5) and the gypsum reaction unit (1), and then the material in the ammonia water unit (5) is introduced into the carbon dioxide micro-nano bubble generating unit (4) through the first pipeline provided with the first circulation pump (402) for reaction, and then the material in the carbon dioxide micro-nano bubble generating unit (4) is introduced into the ammonia water unit (5) through the second pipeline provided with the second circulation pump (405) for reaction; and then part of the material in the ammonia water unit (5) is introduced into the gypsum reaction unit (1) through the third pipeline to react with the gypsum to generate calcium carbonate.

6. The method according to claim 5, characterized in that The method further comprises: returning another part of the material in the ammonia water unit (5) to the ammonia water unit (5).

7. The method according to claim 5 or 6, characterized in that: The method further comprises: passing the tail gas discharged from the gypsum reaction unit (1) into the tail gas purification unit (2) for absorption.

8. The method according to any one of claims 5 to 7, characterized in that: The method further comprises: in the gypsum reaction unit (1), conveying the slurry discharged from the gypsum reaction device (101) through the slurry outlet (105) to the slurry liquid-solid separation device (106) for solid-liquid separation; part or all of the liquid phase obtained by the treatment of the slurry liquid-solid separation device (106) enters the gypsum reaction device (101) through the slurry clear liquid circulation device (103); conveying the solid phase obtained by the treatment of the slurry liquid-solid separation device (106) to the solid-liquid separation device (107) for further solid-liquid separation, thereby obtaining and recovering calcium carbonate solid.

9. The method according to any one of claims 5 to 8, characterized in that: The method further comprises: transporting the material discharged from the gypsum reaction device (101) to the carbon dioxide micro-nano bubble generating device (403) via the first circulation pump (402).

10. The method according to any one of claims 5 to 9, characterized in that: The pH value of the material in the carbon dioxide micro-nano bubble generating device (403) is 6-10.5.

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