A production system for producing calcium carbonate and ammonium sulfate solution from desulfurized gypsum

Abstract

The utility model provides a kind of production system of desulfurization gypsum preparation calcium carbonate and ammonium sulfate solution, including first reaction system, the first reaction system includes first slurry tank, first reaction tank, settling tank and first filter that are sequentially communicated, first slurry tank, first reaction tank, settling tank and first filter are connected by pipeline and slurry pump respectively, the side of first reaction system is also equipped with second reaction system for the secondary reaction of the dilute ammonium sulfate generated in first reaction system. The utility model is discharged to the secondary reaction of dilute ammonium sulfate solution generated in first reaction system to second reaction system, and concentrated sulfuric acid is directly obtained, the process of low-concentration ammonium sulfate solution evaporation concentration to high-concentration ammonium sulfate solution is reduced, and the operating cost of enterprise is further reduced;By setting settling tank, reduce the problem that filter cloth is easily blocked by glue oil-like material entrained by desulfurization gypsum when calcium carbonate is filtered.

Description

Technical Field

[0001] This utility model relates to the field of resource utilization technology of desulfurized gypsum, and in particular to a production system for producing calcium carbonate and ammonium sulfate solutions from desulfurized gypsum. Background Technology

[0002] Thermal power remains the primary form of power generation in my country. To meet national emission standards, thermal power units generally employ flue gas desulfurization (FGD) processes at the boiler tail end to reduce SO2 emissions, the main pollutant. Among these, the limestone wet process is currently the most mature and widely used FGD technology. This process generates desulfurized gypsum, and it is estimated that my country produces over 80 million tons of desulfurized gypsum annually from power plants. However, the comprehensive utilization rate of desulfurized gypsum is low; most of the gypsum is either stockpiled or discarded, which not only occupies land and causes environmental problems but also fails to realize the gypsum's inherent value. Therefore, developing a process route that uses desulfurized gypsum as raw material to convert it into calcium carbonate and ammonium sulfate solutions would not only benefit the current disposal of large stockpiles of gypsum but also potentially bring considerable economic benefits to thermal power plants in the future.

[0003] Currently, most methods involve mixing ammonium bicarbonate with desulfurized gypsum to react and produce calcium carbonate and ammonium sulfate solutions. The specific steps include: placing desulfurized gypsum and water into a reaction vessel, then adding ammonium bicarbonate to react and produce calcium carbonate and ammonium sulfate solutions. The solutions are then separated by filtration, and the separated ammonium sulfate solution needs to be evaporated and concentrated to a predetermined concentration before storage.

[0004] However, in the existing technology for producing calcium carbonate and ammonium sulfate solutions, the raw materials contain a large number of insoluble impurities. During the filtration of calcium carbonate, the oily substances carried by the desulfurized gypsum easily clog the filter cloth, requiring frequent cleaning and replacement, which is time-consuming and labor-intensive. Furthermore, the process of evaporating and concentrating the ammonium sulfate solution from a low concentration to a high concentration is time-consuming, increasing enterprise costs. Utility Model Content

[0005] The main objective of this invention is to provide a production system for producing calcium carbonate and ammonium sulfate solutions from desulfurized gypsum, in order to solve the problems in the existing technology where there are many insoluble impurities in the raw materials during the process of producing calcium carbonate and ammonium sulfate solutions, the glue-like substances carried by the desulfurized gypsum during calcium carbonate filtration easily clog the filter cloth, and the process of evaporating and concentrating the ammonium sulfate solution from low concentration to high concentration takes a long time and increases the enterprise cost.

[0006] To solve the above problems, this utility model adopts the following technical solution: a production system for producing calcium carbonate and ammonium sulfate solution from desulfurized gypsum, including a first reaction system. The first reaction system includes a first mixing tank, a first reaction tank, a settling tank, and a first filter connected in sequence. The first mixing tank, the first reaction tank, the settling tank, and the first filter are connected to each other through pipelines and a mud pump. A second reaction system is also provided on one side of the first reaction system for secondary reaction of the dilute ammonium sulfate produced in the first reaction system.

[0007] Furthermore, the second reaction system includes a second mixing tank, a second reaction vessel, and a second filter connected in sequence. The second mixing tank, the second reaction vessel, and the second filter are connected to a mud pump via pipelines. The first filter includes a liquid output end for discharging dilute ammonium sulfate and a solid output end for discharging calcium carbonate. The liquid output end is connected to the input end of the second mixing tank.

[0008] Furthermore, the second filter has the same structure as the first filter, and the solid output end of the second filter is connected to the input end of the first slurry mixing tank.

[0009] Furthermore, the second filter has an inlet end that is connected to an external water source, and the water in the inlet end is transmitted to the second mixing tank through the liquid output end of the first filter.

[0010] Furthermore, both the first filter and the second filter are vacuum belt filter presses.

[0011] Furthermore, the first and second mixing tanks have the same structure, and at least one stirring component is slidably disposed on the top of each of the first and second mixing tanks.

[0012] Furthermore, each of the mixing components includes a slide rail mounted above the first mixing tank or the second mixing tank, a slider slidably disposed within the slide rail, and a power unit for driving the slider to move along the slide rail. A first motor is fixedly mounted on the top surface of the slider, and the output end of the first motor passes through the slider from top to bottom and is fixedly mounted with a stirring rod for stirring the gypsum slurry.

[0013] Furthermore, the power unit includes a screw rotatably disposed inside the slide rail, with both ends of the screw rotatably connected to both ends of the slide rail along its length. A threaded hole is provided on one side of the slider, and the slider is screwed to the screw through the threaded hole. A second motor is fixedly disposed on one side of the slide rail, and the output end of the second motor passes through the side wall of the slide rail and is fixedly connected to the screw.

[0014] Furthermore, a through hole is provided on the other side of the slider, and a guide rod is provided inside the slide rail. The guide rod is slidably disposed in the through hole, and the two ends of the guide rod are respectively fixedly connected to the two ends of the slide rail in the length direction.

[0015] Furthermore, there are two stirring components, which are respectively located on both sides of the width direction of the corresponding first or second mixing tank.

[0016] The beneficial effects of this utility model are: 1. By discharging the dilute ammonium sulfate solution generated in the first reaction system to the second reaction system for secondary reaction, concentrated ammonium sulfate is directly obtained, reducing the process of evaporating and concentrating the low-concentration ammonium sulfate solution into a high-concentration ammonium sulfate solution, thereby reducing the company's operating costs; by setting up a settling tank, the problem of the glue-like substances carried by the desulfurization gypsum during calcium carbonate filtration being able to clog the filter cloth is reduced. 2. By setting up a stirring component, the granular desulfurized gypsum is broken up, so that the subsequent reaction with ammonium bicarbonate is more complete. Attached Figure Description

[0017] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0018] Figure 1 This is a flowchart of the production system for producing calcium carbonate and ammonium sulfate solution from desulfurized gypsum according to this utility model. Figure 2 This is a schematic diagram of the installation structure of the stirring assembly.

[0019] Explanation of reference numerals in the attached figures 1. First reaction system; 11. First mixing tank; 12. First reaction vessel; 13. Settling tank; 14. First filter; 2. Second reaction system; 21. Second mixing tank; 22. Second reaction vessel; 23. Second filter; 3. Agitator assembly; 31. Slide rail; 32. Slider; 33. Power unit; 331. Screw; 332. Second motor; 333. Guide rod; 34. First motor; 35. Agitator rod. Detailed Implementation

[0020] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Many specific details are set forth in the following description to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0021] Please see Figure 1 As shown, a production system for producing calcium carbonate and ammonium sulfate solution from desulfurized gypsum includes a first reaction system 1. The first reaction system includes a first mixing tank 11, a first reaction tank 12, a settling tank 13, and a first filter 14 connected in sequence. The first mixing tank 11, the first reaction tank 12, the settling tank 13, and the first filter 14 are connected to each other via pipelines and mud pumps.

[0022] During implementation, the weighed desulfurized gypsum is placed in the first mixing tank 11, and then water, 2 to 3 times the weight of the desulfurized gypsum, is added. The mixture is stirred for 5 to 10 minutes until homogeneous. After stirring, the desulfurized gypsum slurry in the mixing tank is pumped to the first reaction tank 12. It should be noted that the first reaction tank 12 is a reaction tank with oxidation aeration function in existing technology, which will not be described in detail here. Next, the sulfite content in the mixed slurry is sampled and tested, and the oxidation aeration time is set according to the sulfite content. After oxidation and aeration are completed, ammonium bicarbonate is added to the desulfurized gypsum slurry. Specifically, ammonium bicarbonate is added at a mass ratio of 4:1. The reaction is carried out for 40 to 60 minutes. During this period, cooling water is used for heating to keep the temperature of the reaction solution between 30 and 45°C. After the reaction is completed, a mixed slurry of calcium carbonate and ammonium sulfate is formed. The reacted calcium carbonate and ammonium sulfate slurry is then discharged into settling tank 13, where settling removes large, insoluble solid particles and heavy metal impurities entrained in the desulfurized gypsum. It should be noted that this additional step avoids the problem in existing technologies where the oily, glue-like substances entrained in the desulfurized gypsum during calcium carbonate filtration easily clog the filter cloth. After the calcium carbonate and ammonium sulfate mixed slurry settles, the impurities at the bottom of the settling tank 13 are discharged. Then, the calcium carbonate and ammonium sulfate mixed slurry in the settling tank 13 is pumped into the first filter 14 through a slurry pump. In this embodiment, the first filter 14 is a vacuum belt filter press in the prior art. The first filter 14 separates calcium carbonate and dilute ammonium sulfate solution from the calcium carbonate and ammonium sulfate mixed slurry. At this time, the calcium carbonate can be dried and packaged, while the dilute ammonium sulfate solution is used for secondary slurry preparation with desulfurized gypsum, that is, to carry out a secondary reaction to convert the dilute ammonium sulfate solution into a dilute ammonium sulfate solution. This reduces the process of evaporating and concentrating the low-concentration ammonium sulfate solution into a high-concentration ammonium sulfate solution, thereby reducing the company's operating costs.

[0023] In this embodiment, a second reaction system 2 is also provided on one side of the first reaction system 1 for secondary reaction of the dilute ammonium sulfate generated in the first reaction system 1. Specifically, the second reaction system 2 includes a second mixing tank 21, a second reaction vessel 22, and a second filter 23 connected in sequence. The second mixing tank 21, the second reaction vessel 22, and the second filter 23 are connected to a mud pump via pipelines. The first filter 14 includes a liquid output end for discharging dilute ammonium sulfate and a solid output end for discharging calcium carbonate. The liquid output end is connected to the input end of the second mixing tank 21 to discharge the dilute ammonium sulfate solution generated in the first reaction system 1 into the second mixing tank 21 for secondary mixing.

[0024] It should be noted that the second mixing tank 21, the second reaction tank 22, and the second filter 23 have the same structure and function as the first mixing tank 11, the first reaction tank 12, and the first filter 14. The working process of the second reaction system 2 is as follows: Desulfurized gypsum is placed into the second mixing tank 21. Then, the dilute ammonium sulfate solution generated in the first reaction system 1 is discharged into the second mixing tank 21 for secondary mixing. The second filter 23 has an inlet end connected to an external water source. The water in the inlet end is transmitted to the second mixing tank 21 through the liquid output end of the first filter 14. That is, desulfurized gypsum is placed into the second mixing tank 21. At the same time, water and dilute ammonium sulfate solution are provided to the second mixing tank 21 through the first filter 14 of the first reaction system 1, so as to mix the desulfurized gypsum, water and dilute ammonium sulfate solution in the second mixing tank 21 to form desulfurized gypsum slurry. Next, the desulfurized gypsum slurry is fed into the second reaction tank 22 for oxidation and aeration. After oxidation and aeration are completed, ammonium bicarbonate is added to the desulfurized gypsum slurry to convert it into a mixed slurry of calcium carbonate and ammonium sulfate. Then, the mixed slurry is separated into calcium carbonate and concentrated ammonium sulfate solution through the second filter 23. It should be noted that by using the dilute ammonium sulfate solution for a secondary slurry preparation reaction in the second reaction system 2 to directly obtain concentrated ammonium sulfate, the process of evaporating and concentrating the low-concentration ammonium sulfate solution into a high-concentration ammonium sulfate solution is reduced, thereby lowering the company's operating costs.

[0025] Preferably, the solid output end of the second filter 23 is connected to the input end of the first mixing tank 11, that is, the calcium carbonate generated by the second reaction system 2 is placed back into the first mixing tank 11 for a secondary reaction to produce higher quality calcium carbonate (content of about 94% calcium carbonate).

[0026] Please see Figure 2As shown, in this embodiment, at least one stirring component 3 is slidably disposed at the top of the first mixing tank 11 and the second mixing tank 21, respectively, to break up the granular desulfurized gypsum through the stirring component 3, so as to make the subsequent reaction with ammonium bicarbonate more complete. Preferably, there are two stirring components 3, which are respectively located on both sides of the width direction of the corresponding first mixing tank 11 or second mixing tank 21. Specifically, each stirring component 3 includes a slide rail 31 mounted above the first mixing tank 11 or the second mixing tank 21, a slider 32 slidably disposed in the slide rail 31, and a power unit 33 for driving the slider 32 to move along the slide rail 31. A first motor 34 is fixedly disposed on the top surface of the slider 32, and the output end of the first motor 34 passes through the slider 32 from top to bottom and is fixedly disposed on a stirring rod 35 for stirring the gypsum slurry.

[0027] The power unit 33 includes a screw 331 rotatably mounted inside the slide rail 31. Both ends of the screw 331 are rotatably connected to the two ends of the slide rail 31 along its length. A threaded hole is provided on one side of the slider 32, which is screwed to the screw 331 through the threaded hole. A second motor 332 is fixedly mounted on one side of the slide rail 31, and the output end of the second motor 332 passes through the side wall of the slide rail 31 and is fixedly connected to the screw 331. In implementation, the first motor 34 is started, driving the stirring rod 35 to rotate and stir the desulfurized gypsum slurry. During stirring, the second motor 332 is started, driving the screw 331 to rotate forward or backward, thereby causing the slider 32, screwed to the screw 331, to reciprocate along the axial direction of the screw 331. This, in turn, causes the stirring rod 35 to reciprocate along the length of the corresponding first mixing tank 11 or second mixing tank 21, thereby making the desulfurized gypsum slurry in the first mixing tank 11 or second mixing tank 21 more uniformly stirred.

[0028] Preferably, a through hole is provided on the other side of the slider 32, and a guide rod 333 is provided inside the slide rail 31. The guide rod 333 is slidably disposed in the through hole, and the two ends of the guide rod 333 are fixedly connected to the two ends of the slide rail 31 in the length direction. By providing a through hole and cooperating with the guide rod 333, the slider 32 is made more stable during movement.

[0029] The above description is only a preferred embodiment of this utility model. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

Claims

1. A production system for producing calcium carbonate and ammonium sulfate solution from desulfurized gypsum, characterized by, The system includes a first reaction system (1), which includes a first mixing tank (11), a first reaction tank (12), a settling tank (13), and a first filter (14) connected in sequence. The first mixing tank (11), the first reaction tank (12), the settling tank (13), and the first filter (14) are connected to each other by pipelines and mud pumps. A second reaction system (2) is also provided on one side of the first reaction system (1) for secondary reaction of the dilute ammonium sulfate produced in the first reaction system (1).

2. The production system for producing calcium carbonate and an ammonium sulfate solution from desulfurized gypsum according to claim 1, characterized by, The second reaction system (2) includes a second mixing tank (21), a second reaction tank (22), and a second filter (23) connected in sequence. The second mixing tank (21), the second reaction tank (22), and the second filter (23) are connected to a mud pump through pipelines. The first filter (14) includes a liquid output end for discharging dilute ammonium sulfate and a solid output end for discharging calcium carbonate. The liquid output end is connected to the input end of the second mixing tank (21).

3. The production system for producing calcium carbonate and an ammonium sulfate solution from desulfurized gypsum according to claim 2, characterized by, The second filter (23) has the same structure as the first filter (14), and the solid output end of the second filter (23) is connected to the input end of the first slurry mixing tank (11).

4. The production system for producing calcium carbonate and an ammonium sulfate solution from desulfurized gypsum according to claim 3, characterized by, The second filter (23) has an inlet end that is connected to an external water source. The water in the inlet end is transmitted to the second mixing tank (21) through the liquid output end of the first filter (14).

5. The production system for producing calcium carbonate and an ammonium sulfate solution from desulfurized gypsum according to claim 2, characterized by, Both the first filter (14) and the second filter (23) are vacuum belt filter presses.

6. The production system for producing calcium carbonate and an ammonium sulfate solution from desulfurized gypsum according to claim 2, characterized by, The first mixing tank (11) and the second mixing tank (21) have the same structure, and at least one stirring component (3) is slidably provided on the top of the first mixing tank (11) and the second mixing tank (21).

7. The production system for producing calcium carbonate and an ammonium sulfate solution from desulfurized gypsum according to claim 6, characterized by, Each of the mixing components (3) includes a slide rail (31) mounted above the first mixing tank (11) or the second mixing tank, a slider (32) slidably disposed within the slide rail (31), and a power unit (33) for driving the slider (32) to move along the slide rail (31). A first motor (34) is fixedly mounted on the top surface of the slider (32), and the output end of the first motor (34) passes through the slider (32) from top to bottom and is fixedly mounted with a stirring rod (35) for stirring gypsum slurry.

8. The production system for producing calcium carbonate and an ammonium sulfate solution from desulfurized gypsum according to claim 7, characterized by, The power unit (33) includes a screw (331) rotatably disposed inside the slide rail (31). The two ends of the screw (331) are rotatably connected to the two ends of the slide rail (31) along its length. A threaded hole is provided on one side of the slider (32), and the slider is screwed to the screw (331) through the threaded hole. A second motor (332) is fixedly disposed on one side of the slide rail (31). The output end of the second motor (332) passes through the side wall of the slide rail (31) and is fixedly connected to the screw (331).

9. The production system for producing calcium carbonate and an ammonium sulfate solution from desulfurized gypsum according to claim 8, characterized by, The slider (32) has a through hole on the other side, and the slide rail (31) has a guide rod (333) inside. The guide rod (333) is slidably disposed in the through hole, and the two ends of the guide rod (333) are fixedly connected to the two ends of the slide rail (31) in the length direction.

10. The production system for producing calcium carbonate and an ammonium sulfate solution from desulfurized gypsum according to claim 6, characterized by, There are two stirring components (3), and the two stirring components (3) are located on both sides of the width direction of the corresponding first mixing tank (11) or second mixing tank (21).

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