Gypsum wet desulphurization system

Abstract

The utility model discloses a gypsum wet desulphurization system which comprises an absorption tower and a flue gas heat exchanger, an oxidation pond is arranged at the lower end of the absorption tower, a first material conveying pipe and a second material conveying pipe are arranged between the absorption tower and the oxidation pond, a circulating pump is arranged on the first material conveying pipe, and a plurality of spraying pipes are arranged at one end of the second material conveying pipe. An oxidation fan is arranged at the bottom of the oxidation pond through an oxygen conveying pipe, a limestone slurry silo is arranged on one side of the bottom of the oxidation pond through a third material conveying pipe and a material conveying pump, a smoke inlet pipe and a smoke exhaust pipe are arranged on the two sides of the absorption tower respectively, and one end of the smoke inlet pipe and one end of the smoke exhaust pipe are both communicated with the smoke heat exchanger. The absorption tower can integrate absorption and oxidation functions, the upper part is an absorption area, the lower part is an oxidation area, raw flue gas subjected to dust removal is in reverse contact with circulating slurry in the absorption tower, is fully absorbed and then is discharged, and meanwhile, a countercurrent air spraying tower is adopted, so that the diameter of the absorption tower is greatly reduced, parts in the tower are greatly reduced, and the scaling possibility is reduced.

Description

Technical Field

[0001] This utility model relates to the technical field of wet desulfurization equipment, specifically a gypsum wet desulfurization system. Background Technology

[0002] During the combustion process of coal-fired boilers, sulfur in the coal is burned to generate a large amount of sulfur dioxide. The state has formulated emission standards for air pollutants in different industries, imposing control requirements on sulfur dioxide emissions. To meet these emission standards and reduce sulfur dioxide emissions, many boilers are equipped with desulfurization systems. Flue gas desulfurization can be divided into three main categories based on the absorbent and products: dry, wet, and semi-dry desulfurization. Among these, the limestone-gypsum wet desulfurization process has advantages such as fast reaction speed, stable operation, high desulfurization efficiency, and mature and reliable technology. The main reaction principle of limestone wet desulfurization is that limestone, as a desulfurizing agent, reacts with sulfur dioxide in the flue gas to generate calcium sulfate, thereby removing sulfur dioxide from the flue gas. The absorbent—limestone (lime) slurry—is fed into the absorption tower and mixes with the flue gas entering the tower. The sulfur dioxide in the flue gas reacts with the calcium carbonate in the absorbent slurry to mainly generate calcium sulfite. Inside the absorption tower, air is blown in by an oxidation fan, and bisulfite ions are oxidized into hydrogen ions and sulfate ions, ultimately generating calcium sulfate dihydrate, i.e., gypsum, which is then removed by the gypsum removal system. The flue gas after desulfurization is discharged into the atmosphere through a chimney.

[0003] The existing technology, patent application number 202420206273.0, describes a sorting and optimization system for poisoned slurry in a limestone-gypsum wet desulfurization system. A liquid separation control valve is installed on the pipeline from the underflow of the gypsum hydrocyclone station to the gypsum belt dewatering machine. An underflow return pipe, connected to the underflow recovery pipe, is installed on the pipeline connecting the gypsum discharge pump and the emergency slurry tank. The underflow return pipe is connected to the overflow port of the gypsum hydrocyclone station via an overflow return pipe. This invention utilizes the effective volume of the emergency slurry tank in the desulfurization system and the sorting effect of the gypsum hydrocyclone to effectively sort the poisoned gypsum slurry, improving the slurry quality of the desulfurization system, thereby increasing the desulfurization efficiency and desulfurizing agent utilization rate, and reducing the time required to dispose of the poisoned slurry. However, the absorption tower has a large diameter, and the internal components increase the possibility of scaling, making operation inconvenient, resulting in lower efficiency and higher costs. Utility Model Content

[0004] The purpose of this invention is to provide a gypsum wet desulfurization system to solve the problems of existing technologies, such as large absorption tower diameter, large internal components which increase the possibility of scaling, inconvenient operation, low efficiency, and high cost.

[0005] To achieve the above objectives, this utility model provides the following technical solution: a gypsum wet desulfurization system, comprising an absorption tower and a flue gas heat exchanger, an oxidation tank at the lower end of the absorption tower, a first conveying pipe and a second conveying pipe between the absorption tower and the oxidation tank, a circulating pump on the first conveying pipe, multiple spray pipes at one end of the second conveying pipe, an oxidation fan on one side of the bottom of the oxidation tank via an oxygen conveying pipe, a limestone slurry silo on one side of the bottom of the oxidation tank via a third conveying pipe and a conveying pump, an inlet pipe and an outlet pipe on both sides of the absorption tower, and one end of both the inlet pipe and the outlet pipe being connected to the flue gas heat exchanger, and a sludge discharge pipe and a sludge discharge pump on one side of the bottom of the oxidation tank.

[0006] Furthermore, a booster fan is provided at one end of the smoke inlet pipe, and a dust filter is provided at the other end of the smoke inlet pipe.

[0007] Furthermore, a demister is provided at one end of the exhaust pipe near the absorption tower, and a chimney is provided at the other end of the exhaust pipe.

[0008] Furthermore, a first agitator is provided in the upper part of the limestone slurry silo, and a second agitator is provided in the lower part of the oxidation tank.

[0009] Furthermore, both the first and second stirrers include a stirring motor, and one end of each stirring motor is provided with a first stirring blade via a stirring shaft.

[0010] Furthermore, a second stirring blade is provided on one side of the first stirring blade, and the second stirring blade is a semi-circular blade.

[0011] Furthermore, the spray pipe is an annular pipe, and the diameter of the multiple spray pipes decreases sequentially from top to bottom, with multiple spray heads provided on the lower side of the spray pipe.

[0012] Compared with the prior art, the beneficial effects of this utility model are:

[0013] This invention integrates absorption and oxidation functions by incorporating an oxidation tank at the lower end of the absorption tower. The upper part is the absorption zone, and the lower part is the oxidation zone. The raw flue gas after dust removal comes into countercurrent contact with the circulating slurry in the absorption tower and is fully absorbed before being discharged. At the same time, the use of a counter-current air spray tower significantly reduces the diameter of the absorption tower and greatly reduces the number of internal components, thereby reducing the possibility of scaling and reducing costs. Moreover, it has a high desulfurization efficiency and uses inexpensive and readily available limestone as the absorbent, which can effectively control operating costs.

[0014] This invention utilizes inlet and outlet pipes on both sides of the absorption tower, with one end of each pipe connected to a flue gas heat exchanger. The original flue gas is used to heat the desulfurized flue gas, raising the exhaust temperature above the dew point. This reduces corrosion of the inlet duct and chimney, and improves the diffusion of pollutants. Simultaneously, it lowers the temperature of the flue gas entering the absorption tower, reducing the requirements for corrosion protection within the tower.

[0015] Furthermore, this invention provides a limestone slurry silo on one side of the bottom of the oxidation tank via a third feed pipe and a feed pump, which can supply fresh limestone slurry to the oxidation tank to replenish the consumed limestone and maintain a certain pH value in the absorption slurry.

[0016] This invention features a first agitator located at the upper part of a limestone slurry silo and a second agitator located at the lower part of an oxidation tank. Both the first and second agitators include a stirring motor, and each motor has a first stirring blade connected to a stirring shaft at one end. The first agitator is used to thoroughly mix the limestone slurry inside the silo, facilitating the even replenishment of consumed limestone into the absorption tower. Simultaneously, the second agitator is used to stir the middle part of the oxidation tank, maintaining a certain pH value in the limestone slurry and ensuring sufficient contact between oxygen and calcium sulfite in the spray liquid, thereby improving the efficiency of the oxidation reaction. Attached Figure Description

[0017] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings:

[0018] Figure 1 This is a schematic diagram of the overall structure of this utility model;

[0019] Figure 2 This is a cross-sectional view of the oxidation tank structure of this utility model;

[0020] Figure 3 This is a schematic diagram of the spray pipe structure of this utility model.

[0021] In the diagram: 1. Absorption tower; 2. Oxidation pond; 3. Flue gas inlet pipe; 4. Dust filter; 5. Flue gas heat exchanger; 6. Exhaust pipe; 7. Demister; 8. Chimney; 9. Booster fan; 10. First conveying pipe; 11. Circulating pump; 12. Sludge discharge pipe; 13. Sludge discharge pump; 14. Second conveying pipe; 15. Oxygen supply pipe; 16. Oxidation fan; 17. Limestone slurry silo; 18. Conveying pump; 19. Third conveying pipe; 20. First agitator; 21. Agitator motor; 22. First agitator blade; 23. Agitator shaft; 24. Second agitator blade; 25. Spray pipe; 26. Spray head. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0023] Please see Figure 1 , Figure 2 , Figure 3 In this embodiment of the present invention, a gypsum wet desulfurization system includes an absorption tower 1 and a flue gas heat exchanger 5. An oxidation tank 2 is provided at the lower end of the absorption tower 1. A first conveying pipe 10 and a second conveying pipe 14 are provided between the absorption tower 1 and the oxidation tank 2. A circulation pump 11 is provided on the first conveying pipe 10. A plurality of spray pipes 25 are provided at one end of the second conveying pipe 14. An oxidation fan 16 is provided on one side of the bottom of the oxidation tank 2 through an oxygen supply pipe 15. A booster fan 9 is provided at one end of the flue gas inlet pipe 3. A dust filter 4 is also provided at the other end of the flue gas inlet pipe 3. A sludge discharge pipe 12 and a sludge discharge pump 13 are provided on one side of the bottom of the oxidation tank 2. Lime water is sprayed through the spray pipes 25 in the absorption tower 1 to absorb sulfur dioxide and form calcium sulfite. The sprayed mixture enters the oxidation tank 2. Calcium sulfite reacts with oxygen to form calcium sulfate. It can integrate absorption and oxidation functions. The upper part is the absorption zone and the lower part is the oxidation zone. It has high desulfurization efficiency, compact structure, and uses inexpensive and readily available limestone as the absorbent, which can effectively control operating costs.

[0024] like Figure 1 As shown, in order to regulate the temperature of the flue gas, a limestone slurry silo 17 is provided on one side of the bottom of the oxidation tank 2 via a third feed pipe 19 and a feed pump 18. The absorption tower 1 is provided with an inlet pipe 3 and an outlet pipe 6 on both sides, and one end of the inlet pipe 3 and the outlet pipe 6 are connected to the flue gas heat exchanger 5. The end of the outlet pipe 6 near the absorption tower 1 is provided with a demister 7, and the other end of the outlet pipe 6 is provided with a chimney 8, which facilitates the use of the original flue gas to heat the desulfurized clean flue gas, so that the exhaust temperature reaches above the dew point, reducing the corrosion of the inlet pipe and the chimney 8, and improving the diffusion of pollutants; at the same time, it reduces the temperature of the flue gas entering the absorption tower 1 and reduces the process technology requirements for corrosion prevention inside the tower.

[0025] like Figure 1 and Figure 3As shown, in order to ensure sufficient contact between oxygen and calcium sulfite in the spray liquid, a first agitator 20 is installed at the upper part of the limestone slurry silo 17, and a second agitator is installed at the lower part of the oxidation tank 2. Both the first agitator 20 and the second agitator include a stirring motor 21. One end of the stirring motor 21 is equipped with a first stirring blade 22 through a stirring shaft 23. The first agitator 20 is used to fully stir and mix the limestone slurry inside the limestone slurry silo 17, so as to evenly replenish the consumed limestone into the absorption tower 1. At the same time, the second agitator can be used to stir the middle part of the oxidation tank 2, so as to maintain a certain pH value of the limestone slurry and ensure sufficient contact between oxygen and calcium sulfite in the spray liquid, thereby improving the efficiency of the oxidation reaction.

[0026] like Figure 1 and Figure 2 As shown, in order to improve the mixing efficiency of the agitator, a second agitator blade 24 is provided on one side of the first agitator blade 22. The second agitator blade 24 is a semi-circular blade, which increases the mixing area of ​​the agitator blade and is beneficial to improving the mixing efficiency of the agitator.

[0027] like Figure 1 and Figure 3 As shown, in order to improve the efficiency of sulfur dioxide scrubbing absorption in flue gas, the spray pipe 25 is also set as an annular pipe, and the diameter of the multiple spray pipes 25 decreases from top to bottom. Multiple spray heads 26 are provided on the lower side of the spray pipe 25, which increases the spray area and is conducive to improving the efficiency of sulfur dioxide scrubbing absorption in flue gas.

[0028] The working principle and usage process of this utility model are as follows: During use, flue gas from the boiler enters the inlet pipe 3. After being filtered by the dust collector 4, it enters the absorption tower 1 under the action of the booster fan 9. The absorption tower 1 is a counter-current air-spray tower structure. Lime water is sprayed through the spray pipe 25 inside the absorption tower 1 to absorb sulfur dioxide and form calcium sulfite. The sprayed mixture enters the oxidation tank 2, where calcium sulfite reacts with oxygen to form calcium sulfate. This structure integrates absorption and oxidation functions. The upper part is the absorption zone, and the lower part is the oxidation zone. The original flue gas after dust removal comes into counter-current contact with the circulating slurry in the absorption tower 1 and is fully absorbed before being discharged. The reaction product slurry reaches a certain density and is discharged after dehydration to form gypsum.

[0029] Finally, it should be noted that the above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Although the utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A gypsum wet desulfurization system, comprising an absorption tower (1) and a flue gas heat exchanger (5), characterized in that: The absorption tower (1) is provided with an oxidation tank (2) at its lower end. A first conveying pipe (10) and a second conveying pipe (14) are provided between the absorption tower (1) and the oxidation tank (2). A circulation pump (11) is provided on the first conveying pipe (10). A plurality of spray pipes (25) are provided at one end of the second conveying pipe (14). An oxidation blower (16) is provided on one side of the bottom of the oxidation tank (2) through an oxygen conveying pipe (15). A limestone slurry silo (17) is provided on one side of the bottom of the oxidation tank (2) through a third conveying pipe (19) and a conveying pump (18). A flue gas inlet pipe (3) and a flue gas outlet pipe (6) are provided on both sides of the absorption tower (1). One end of the flue gas inlet pipe (3) and the flue gas outlet pipe (6) are connected to a flue gas heat exchanger (5). A sludge discharge pipe (12) and a sludge discharge pump (13) are provided on one side of the bottom of the oxidation tank (2).

2. A gypsum wet desulphurisation system according to claim 1, characterised in that: One end of the smoke inlet pipe (3) is equipped with a booster fan (9), and the other end of the smoke inlet pipe (3) is also equipped with a dust filter (4).

3. A gypsum wet desulphurisation system according to claim 1, characterised in that: The exhaust pipe (6) is equipped with a demister (7) at one end near the absorption tower (1), and a chimney (8) is provided at the other end of the exhaust pipe (6).

4. A gypsum wet desulphurisation system according to claim 1, characterised in that: The upper part of the limestone slurry silo (17) is equipped with a first agitator (20), and the lower part of the oxidation tank (2) is equipped with a second agitator.

5. A gypsum wet desulphurisation system according to claim 4, characterised in that: The first stirrer (20) and the second stirrer both include a stirring motor (21), and one end of the stirring motor (21) is provided with a first stirring blade (22) through a stirring shaft (23).

6. A gypsum wet desulphurisation system according to claim 5, characterised in that: A second stirring blade (24) is provided on one side of the first stirring blade (22), and the second stirring blade (24) is a semi-circular blade.

7. A gypsum wet desulphurisation system according to claim 1, characterised in that: The spray pipe (25) is an annular pipe, and the diameter of the multiple spray pipes (25) decreases from top to bottom. Multiple spray heads (26) are provided on the lower side of the spray pipe (25).

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