A segmented countercurrent boiler flue gas desulfurization device and desulfurization method thereof

Abstract

The present invention belongs to the technical field of flue gas desulfurization. The present invention provides a segmented countercurrent boiler flue gas desulfurization device and a desulfurization method thereof, which solves the problems of low flue gas desulfurization efficiency, poor desulfurization effect, and influence on the deep desulfurization of flue gas. Through a segmented countercurrent boiler flue gas desulfurization device, firstly, by setting a multi-stage absorption tower, the contact and reaction time between flue gas and slurry can be extended, the reaction is more thorough, and the desulfurization efficiency is higher. Secondly, the slurry with the highest effective content of absorbent is made to absorb and chemically react with the part with the lowest sulfur dioxide content in the flue gas, and the part with the lowest effective content of absorbent is made to absorb and react with the part with the highest sulfur dioxide content in the flue gas, the reaction is more thorough, and the desulfurization efficiency can be effectively improved and the sulfur dioxide emission concentration in the flue gas can be reduced.

Description

Technical Field

[0001] The invention relates to the technical field of flue gas desulfurization, and in particular to a segmented countercurrent boiler flue gas desulfurization device and a desulfurization method thereof. Background Art

[0002] In order to meet environmental protection requirements, the wet flue gas desulfurization process usually uses limestone and quicklime as raw materials to prepare slurry, which is fully mixed with the flue gas emitted by coal-fired boilers, absorbs sulfur dioxide in the flue gas to produce calcium sulfite, and oxidizes it to form gypsum and collects it, thereby achieving the purpose of desulfurization. Currently, limestone gypsum wet desulfurization is the mainstream technology in desulfurization technology.

[0003] The key component or core of the limestone gypsum wet desulfurization technology is the absorption tower. The process flow in the absorption tower can be summarized into the following main parts: flue gas system, the original flue gas enters the absorption tower through the original flue gas duct, flows upward in the absorption tower, and is fully in contact with the falling slurry sprayed from the circulating spray through the spray pipe and nozzle. The sulfur dioxide is absorbed, and the clean flue gas passes through the demister (to capture droplets) and the outlet of the absorption tower, then enters the clean flue gas duct and is discharged into the chimney; slurry circulation system: limestone slurry is sprayed through the slurry circulation pump, slurry circulation pipeline, and slurry nozzle. The slurry sprayed downward is fully in contact with the upward flowing flue gas, a chemical reaction occurs, and the SO2 in the flue gas is absorbed and falls into the slurry pool. In the circulating slurry pool of the absorption tower, oxidizing air is used to oxidize calcium sulfite into calcium sulfate. In order to maintain the concentration of the gypsum slurry, the gypsum slurry discharge pump is used to send the gypsum slurry from the absorption tower to the gypsum dehydration system. The slurry in the slurry pool at the bottom of the absorption tower passes through the slurry circulation pump and the slurry pipeline, and then enters the upper part of the absorption tower. After passing through the spray pipe and nozzle, the slurry falls into the slurry pool, and then is drawn out through the slurry circulation pump and enters the next cycle, and this cycle is repeated; Gypsum slurry discharge system: During the slurry circulation process, due to the full contact and reaction between the falling slurry and the rising flue gas, when the gypsum concentration in the slurry rises to a certain value, it needs to be maintained below a certain concentration, and passes through the gypsum slurry discharge pump, the gypsum slurry discharge pipe, the gypsum preparation system, and finally forms gypsum and desulfurization wastewater. Under normal circumstances, the gypsum slurry concentration of the absorption tower is generally controlled at about 20-25% according to the design; Slurry replenishment system: Since the sulfur dioxide in the flue gas is continuously absorbed, it is necessary to continuously replenish the desulfurization absorbent through the absorption liquid replenishment pipe; Oxidation air system: Since in the absorption tower, the process product is insoluble calcium sulfite, the calcium sulfite has a small particle size and is unstable, and needs to undergo an oxidation reaction to produce calcium sulfate and carry water to form gypsum and collect it. Usually, an oxidation fan is used to blow in air. Other systems include agitator, monitoring, water replenishment, emergency cooling water, demister and cleaning.

[0004] In the existing normal desulfurization process, the main components of the circulating slurry are gypsum and a small amount of absorbent CA ions. Gypsum not only does not desulfurize during the circulation process, but due to its high content, it hinders the adsorption of sulfur in the flue gas by the absorbent to a certain extent. In addition, it is an invalid cycle, which increases the circulation volume and the density of the slurry, and has an adverse effect on the deep desulfurization of the flue gas to a certain extent. There are problems such as low flue gas desulfurization efficiency, poor desulfurization effect, and influence on the deep desulfurization of the flue gas. Summary of the invention

[0005] In order to solve the above-mentioned technical problems of low flue gas desulfurization efficiency, poor desulfurization effect and influence on deep desulfurization of flue gas, the present invention provides a staged countercurrent boiler flue gas desulfurization device and a desulfurization method thereof.

[0006] A segmented countercurrent boiler flue gas desulfurization device comprises a segmented flue gas desulfurization tower and a slurry circulation pipeline, wherein the segmented flue gas desulfurization tower is connected to the slurry circulation pipeline.

[0007] Furthermore, the flue gas staged desulfurization tower comprises: a raw smoke inlet pipe port, a first-stage desulfurization tower, a second-stage desulfurization tower, a third-stage desulfurization tower and a clean smoke outlet pipe port, the raw smoke inlet pipe port, the first-stage desulfurization tower, the second-stage desulfurization tower, the third-stage desulfurization tower and the clean smoke outlet pipe port are connected in sequence, the diameter of each connecting point between the first-stage desulfurization tower, the second-stage desulfurization tower and the third-stage desulfurization tower is smaller than the diameter of the first-stage desulfurization tower, the second-stage desulfurization tower and the third-stage desulfurization tower, and the first-stage desulfurization tower, the second-stage desulfurization tower and the third-stage desulfurization tower are respectively connected to the slurry circulation pipeline.

[0008] Furthermore, a first-stage slurry nozzle is arranged above the first-stage desulfurization tower, and a first-stage slurry collecting well is arranged below the first-stage desulfurization tower; a second-stage slurry nozzle is arranged above the second-stage desulfurization tower, and a second-stage slurry collecting well is arranged below the second-stage desulfurization tower; a third-stage slurry nozzle is arranged above the third-stage desulfurization tower, and a third-stage slurry collecting well is arranged below the third-stage desulfurization tower; the first-stage slurry nozzle, the first-stage slurry collecting well, the second-stage slurry nozzle, the second-stage slurry collecting well, the third-stage slurry nozzle and the third-stage slurry collecting well are respectively connected to the slurry circulation pipeline.

[0009] Furthermore, the slurry circulation pipeline includes: a first section slurry inlet pipe, a second section slurry inlet pipe, a third section slurry inlet pipe, a desulfurization tower slurry inlet box, a gypsum slurry separator, a first section slurry discharge pipe and a connecting pipe, the first section slurry nozzle is connected to the second section slurry collecting well through the first section slurry inlet pipe, the second section slurry nozzle is connected to the third section slurry collecting well through the second section slurry inlet pipe, the third section slurry nozzle is connected to the desulfurization tower slurry inlet box through the third section slurry inlet pipe, the desulfurization tower slurry inlet box is connected to the gypsum slurry separator through the connecting pipe, and the gypsum slurry separator is connected to the first section slurry collection well through the first section slurry discharge pipe.

[0010] Furthermore, the first section of the slurry inlet pipe is provided with a first section of the slurry inlet pump, the second section of the slurry inlet pipe is provided with a second section of the slurry inlet pump, the third section of the slurry inlet pipe is provided with a third section of the slurry inlet pump, and the first section of the slurry discharge pipe is provided with a first section of the slurry discharge pump.

[0011] Furthermore, a slurry feeding pipe is arranged on the slurry inlet box of the desulfurization tower, a gypsum slurry discharge pipe is arranged on the gypsum slurry separator, and a gypsum slurry discharge pump is arranged on the gypsum slurry discharge pipe.

[0012] Furthermore, the first-stage slurry collecting well is provided with a first-stage slurry agitator and a first-stage slurry oxidation fan, the second-stage slurry collecting well is provided with a second-stage slurry agitator and a second-stage slurry oxidation fan, and the third-stage slurry collecting well is provided with a third-stage slurry agitator and a third-stage slurry oxidation fan.

[0013] A desulfurization method for a staged countercurrent boiler flue gas desulfurization device, the specific steps are as follows:

[0014] S1: Operation device. The slurry in the desulfurization tower slurry box is ejected from the third section slurry nozzle through the third section slurry pipe under the action of the third section slurry pump. The slurry ejected from the third section slurry nozzle enters the third section slurry collection well. The slurry is stirred and oxidized by the third section slurry agitator and the third section slurry oxidation fan, and then ejected from the second section slurry nozzle under the action of the second section slurry pump. The slurry ejected from the second section slurry nozzle enters the second section slurry collection well. The slurry is stirred and oxidized by the second section slurry agitator and the second section slurry oxidation fan. After being stirred and oxidized by the fan, the slurry is ejected from the first slurry nozzle under the action of the first slurry inlet pump. The slurry ejected from the first slurry nozzle enters the first slurry collecting well. After being stirred and oxidized by the first slurry agitator and the first slurry oxidation fan, the slurry enters the gypsum slurry separator under the action of the first slurry discharge pump. The separated secondary use slurry enters the desulfurization tower slurry inlet box. The separated solid-liquid mixture is discharged through the gypsum slurry discharge pipe under the action of the gypsum slurry discharge pump, thus achieving slurry circulation.

[0015] S2: The boiler flue gas is introduced into the raw flue gas inlet pipe, and the boiler flue gas passes through the first desulfurization tower, the second desulfurization tower and the third desulfurization tower in sequence, and the boiler flue gas is mixed with the slurry sprayed from the first slurry nozzle, the second slurry nozzle and the third slurry nozzle. The slurry removes the sulfide in the boiler flue gas and reaches the gypsum slurry separator through the circulation system and is separated and discharged.

[0016] The beneficial effects of the present invention are:

[0017] The present invention provides a segmented countercurrent boiler flue gas desulfurization device and a desulfurization method thereof. Through a segmented countercurrent boiler flue gas desulfurization device, firstly, by setting a multi-stage absorption tower, the contact and reaction time between flue gas and slurry can be extended, the reaction is more thorough, and the desulfurization efficiency is higher. Secondly, the slurry with the highest effective absorbent content is made to absorb and chemically react with the part with the lowest sulfur dioxide content in the flue gas, and the part with the lowest effective absorbent content is made to absorb and react with the part with the highest sulfur dioxide content in the flue gas, the reaction is more thorough, and the desulfurization efficiency can be effectively improved and the sulfur dioxide emission concentration in the flue gas can be reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the specific implementation methods of the present invention or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 It is a schematic diagram of the structure of the present invention;

[0020] in:

[0021] Flue gas segmented desulfurization tower-101, slurry circulation pipeline-102, raw flue gas inlet pipe-30, first section desulfurization tower-1, second section desulfurization tower-2, third section desulfurization tower-3, clean flue gas outlet-31, first section slurry nozzle-4, first section slurry collection well-17, second section slurry nozzle-5, second section slurry collection well-18, third section slurry nozzle-6, third section slurry collection well-19, first section slurry inlet pipe-12, second section slurry inlet pipe-13, third section slurry inlet pipe-14, desulfurization tower slurry inlet box -21, gypsum slurry separator -20, first section slurry discharge pipe -15, connecting pipe -22, first section slurry inlet pump -7, second section slurry inlet pump -8, third section slurry inlet pump -9, first section slurry discharge pump -10, slurry replenishment pipe -23, gypsum slurry discharge pipe -16, gypsum slurry discharge pump -11, first section slurry agitator -24, first section slurry oxidation fan -27, second section slurry agitator -25, second section slurry oxidation fan -28, third section slurry agitator -26, third section slurry oxidation fan -29. DETAILED DESCRIPTION

[0022] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] It should be noted that the various installation methods and technical terms mentioned in the present invention are technical terms that have long been clearly known in the relevant technical field, so no further explanation is given. In addition, the same reference numerals are used for the same components, but this does not affect nor constitute an accurate understanding of the technical solution by those skilled in the art.

[0024] Embodiment 1:

[0025] The present invention relates to a segmented countercurrent boiler flue gas desulfurization device, comprising: a segmented flue gas desulfurization tower 101 and a slurry circulation pipeline 102, wherein the segmented flue gas desulfurization tower is connected to the slurry circulation pipeline 102, and such a configuration solves the problems of low flue gas desulfurization efficiency, poor desulfurization effect, and influence on deep desulfurization of flue gas. By dividing the desulfurization tower into multiple sections, the flue gas and the slurry are fully reacted, the desulfurization efficiency is improved, and a good desulfurization effect is achieved.

[0026] The flue gas staged desulfurization tower 101 comprises: a raw smoke air inlet 30, a first stage desulfurization tower 1, a second stage desulfurization tower 2, a third stage desulfurization tower 3 and a clean smoke air outlet 31. The raw smoke air inlet 30, the first stage desulfurization tower 1, the second stage desulfurization tower 2, the third stage desulfurization tower 3 and the clean smoke air outlet 31 are connected in sequence. The diameter of each connection point between the first stage desulfurization tower 1, the second stage desulfurization tower 2 and the third stage desulfurization tower 3 is smaller than the diameter of the first stage desulfurization tower 1, the second stage desulfurization tower 2 and the third stage desulfurization tower 3. The first stage desulfurization tower 1, the second stage desulfurization tower 2 and the third stage desulfurization tower 3 are connected to the slurry circulation pipeline 102 respectively. Such an arrangement solves the problems of poor desulfurization effect and low desulfurization efficiency. By setting the connection between two adjacent desulfurization towers to a small diameter, the flue gas is gathered again when entering the next desulfurization tower from one desulfurization tower, thereby improving the reaction efficiency of the flue gas and the slurry and thus improving the flue gas desulfurization efficiency.

[0027] A first-stage slurry nozzle 4 is arranged at the top of the first-stage desulfurization tower 1, and a first-stage slurry collecting well 17 is arranged at the bottom of the first-stage desulfurization tower 1; a second-stage slurry nozzle 5 is arranged at the top of the second-stage desulfurization tower 2, and a second-stage slurry collecting well 18 is arranged at the bottom of the second-stage desulfurization tower 2; a third-stage slurry nozzle 6 is arranged at the top of the third-stage desulfurization tower 3, and a third-stage slurry collecting well 19 is arranged at the bottom of the third-stage desulfurization tower 3; the first-stage slurry nozzle 4, the first-stage slurry collecting well 17, the second-stage slurry nozzle 5, the second-stage slurry collecting well 18, the third-stage slurry nozzle 6 and the third-stage slurry collecting well 19 are respectively connected to the slurry circulation pipeline 102, wherein the spray directions of each nozzle are staggeredly arranged upward and downward, so that the slurry covers the entire space, thereby increasing the contact area between the flue gas and the slurry, and greatly improving the reaction efficiency.

[0028] The slurry circulation pipeline 102 includes: a first section slurry inlet pipe 12, a second section slurry inlet pipe 13, a third section slurry inlet pipe 14, a desulfurization tower slurry inlet box 21, a gypsum slurry separator 20, a first section slurry discharge pipe 15 and a connecting pipe 22. The first section slurry nozzle 4 is connected to the second section slurry collection well 18 through the first section slurry inlet pipe 12, the second section slurry nozzle 5 is connected to the third section slurry collection well 19 through the second section slurry inlet pipe 13, the third section slurry nozzle 6 is connected to the desulfurization tower slurry inlet box 21 through the third section slurry inlet pipe 14, the desulfurization tower slurry inlet box 21 is connected to the gypsum slurry separator 20 through the connecting pipe 22, and the gypsum slurry separator 20 is connected to the first section slurry collection well 17 through the first section slurry discharge pipe 15. This arrangement connects the slurry circulation pipeline with the desulfurization tower, achieves the effect of slurry circulation, allows the flue gas desulfurization work to continue, and improves the flue gas desulfurization efficiency.

[0029] The first section slurry inlet pipe 12 is provided with a first section slurry inlet pump 7, the second section slurry inlet pipe 13 is provided with a second section slurry inlet pump 8, the third section slurry inlet pipe 14 is provided with a third section slurry inlet pump 9, and the first section slurry discharge pipe 15 is provided with a first section slurry discharge pump 10. The slurry is fed in or discharged through the pump body to increase the flow force of the slurry, so that the slurry flows smoothly to avoid blockage.

[0030] The desulfurization tower slurry inlet box 21 is provided with a slurry replenishing pipe 23, the gypsum slurry separator 20 is provided with a gypsum slurry discharge pipe 16, and the gypsum slurry discharge pipe 16 is provided with a gypsum slurry discharge pump 11. The consumed slurry is continuously replenished through the slurry replenishing pipe 23 to prevent insufficient slurry from affecting the flue gas desulfurization efficiency.

[0031] The first-stage slurry collecting well 17 is provided with a first-stage slurry agitator 24 and a first-stage slurry oxidation fan 27, the second-stage slurry collecting well 18 is provided with a second-stage slurry agitator 25 and a second-stage slurry oxidation fan 28, and the third-stage slurry collecting well 19 is provided with a third-stage slurry agitator 26 and a third-stage slurry oxidation fan 29. Such a configuration improves the secondary utilization efficiency of the slurry and achieves the effect of saving resources and saving costs.

[0032] The present invention relates to a desulfurization method for a staged countercurrent boiler flue gas desulfurization device, and the specific steps are as follows:

[0033] S1: Operation device, the slurry in the desulfurization tower slurry box 21 is ejected from the third-stage slurry nozzle 6 through the third-stage slurry inlet pipe 14 under the action of the third-stage slurry inlet pump 9, the slurry ejected from the third-stage slurry nozzle 6 enters the third-stage slurry collecting well 19, the slurry is stirred and oxidized by the third-stage slurry agitator 26 and the third-stage slurry oxidation fan 29, and then ejected from the second-stage slurry nozzle 5 under the action of the second-stage slurry inlet pump 8, the slurry ejected from the second-stage slurry nozzle 5 enters the second-stage slurry collecting well 18, the slurry is stirred and oxidized by the second-stage slurry agitator 25 and the second-stage slurry oxidation fan 29. After being stirred and oxidized by the first-stage slurry inlet pump 7, the slurry is ejected from the first-stage slurry nozzle 4. The slurry ejected from the first-stage slurry nozzle 4 enters the first-stage slurry collecting well 17. After being stirred and oxidized by the first-stage slurry agitator 24 and the first-stage slurry oxidation fan 27, the slurry enters the gypsum slurry separator 20 under the action of the first-stage slurry discharge pump 10. The separated secondary use slurry enters the desulfurization tower slurry inlet box 21. The separated solid-liquid mixture is discharged through the gypsum slurry discharge pipe 16 under the action of the gypsum slurry discharge pump 11, thus achieving slurry circulation.

[0034] S2: The boiler flue gas is introduced into the raw flue gas inlet port 30, so that the boiler flue gas passes through the first-stage desulfurization tower 1, the second-stage desulfurization tower 2 and the third-stage desulfurization tower 3 in sequence, and the boiler flue gas is mixed with the slurry sprayed from the first-stage slurry nozzle 4, the second-stage slurry nozzle 5 and the third-stage slurry nozzle 6. The slurry removes the sulfide in the boiler flue gas and reaches the gypsum slurry separator 20 along the circulation system and is separated and discharged.

[0035] The present invention divides the flue channel into multiple relatively independent sections, each of which is arranged flatly, and each divided section is used as an independent desulfurization tower section. A variable diameter is set at the connection between two adjacent tower sections to promote further mixing of flue gas. The flue gas flows horizontally in the tower section, the spray pipe is arranged horizontally, and the nozzles are evenly arranged on the spray pipe. The spray direction is staggered upward and downward, and the coverage space is large, ensuring that there is no dead angle for the exchange of slurry and flue gas. A slurry collection well is set at the bottom of each desulfurization tower section, and the slurry is collected in the slurry collection well and used as the slurry for the previous desulfurization tower or the gypsum discharge slurry. In the present invention, the sulfur dioxide concentration of the flue gas entering the first-stage desulfurization tower 1 from the original smoke inlet pipe 30 is the highest, and the absorbent concentration in the corresponding slurry is the lowest; the sulfur dioxide concentration of the flue gas entering the third-stage desulfurization tower 3 is the lowest, and the absorbent content in the corresponding slurry is the highest. In this way, the part with the lowest absorbent absorbs and reacts with the part with the highest sulfur dioxide content in the flue gas, and the slurry with the highest absorbent content absorbs and chemically reacts with the part with the lowest sulfur dioxide content in the flue gas, which can effectively improve the desulfurization efficiency and reduce the emission limit of sulfur dioxide, and solves the problem that gypsum not only does not desulfurize during the circulation process, but also hinders the adsorption of sulfur in the absorbent and flue gas to a certain extent due to its high content, and it is an invalid cycle, which increases the circulation volume, increases the density of the slurry, and affects the deep desulfurization of the flue gas.

[0036] Working principle:

[0037] Flue gas flow: The raw flue gas enters from the raw flue gas inlet port 30 and passes through the first desulfurization tower 1, the second desulfurization tower 2, and the third desulfurization tower 3 in sequence, and is discharged from the clean flue gas outlet port 31, and after subsequent treatment, is discharged into the atmosphere through the chimney.

[0038] Slurry process: The slurry comes from the gypsum slurry separator 20. A slurry feeding pipe 23 is provided on the upper part of the gypsum slurry separator 20. The consumed slurry is continuously replenished through the slurry feeding pipe 23. The desulfurized slurry is sent to the third-stage slurry nozzle 6 through the third-stage slurry feed pump 9 and the third-stage slurry feed pipe 14. In the third-stage desulfurization tower 3, the horizontally flowing flue gas from the second-stage desulfurization tower 2 fully reacts with the slurry sprayed from the vertically arranged third-stage slurry nozzle 6. The desulfurized slurry is collected in the third-stage slurry collection well 19 and then sent to the second-stage slurry nozzle 5 through the second-stage slurry feed pump 8 and the second-stage slurry feed pipe 13. In the second stage desulfurization tower 2, the flue gas flowing horizontally from the first stage desulfurization tower 1 fully reacts with the slurry sprayed from the second stage slurry nozzle 5 arranged vertically in the second stage desulfurization tower 2, and the desulfurized slurry is collected in the second stage slurry collection well 18, and then sent to the first stage slurry nozzle 4 through the first stage slurry feed pump 7 and the first stage slurry feed pipe 12. In the first stage desulfurization tower 1, the flue gas flowing horizontally fully reacts with the slurry sprayed from the first stage slurry nozzle 4 arranged vertically in the first stage desulfurization tower 1, and the desulfurized slurry is collected in the first stage slurry collection well 17, and then discharged into the gypsum slurry separator 20 through the first stage slurry discharge pipe 15 and the first stage slurry discharge pump 10. At the top of the gypsum slurry separator 20, the overflow liquid is sent to the desulfurization tower slurry feed box 21 through the connecting pipe 22, and at the bottom of the gypsum slurry separator 20, the gypsum slurry is sent to the gypsum preparation system through the gypsum slurry discharge pump 11 and the gypsum slurry discharge pipe 16.

[0039] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the invention may be implemented in other specific forms without departing from the spirit or essential features of the invention. Therefore, the embodiments should be considered exemplary and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations falling within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any reference numeral in a claim should not be considered as limiting the claim to which it relates.

[0040] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any slight modification, equivalent substitution and improvement made to the above embodiment based on the technical essence of the present invention should be included in the protection scope of the technical solution of the present invention.

Claims

1. A staged countercurrent boiler flue gas desulfurization device, characterized in that: include: A flue gas segmented desulfurization tower (101) and a slurry circulation pipeline (102), wherein the flue gas segmented desulfurization tower is in communication with the slurry circulation pipeline (102); The flue gas staged desulfurization tower (101) comprises: a raw smoke inlet pipe opening (30), a first stage desulfurization tower (1), a second stage desulfurization tower (2), a third stage desulfurization tower (3) and a clean smoke outlet pipe opening (31); the raw smoke inlet pipe opening (30), the first stage desulfurization tower (1), the second stage desulfurization tower (2), the third stage desulfurization tower (3) and the clean smoke outlet pipe opening (31) are connected in sequence; the diameter of each connection point between the first stage desulfurization tower (1), the second stage desulfurization tower (2) and the third stage desulfurization tower (3) is smaller than the diameter of the first stage desulfurization tower (1), the second stage desulfurization tower (2) and the third stage desulfurization tower (3); the first stage desulfurization tower (1), the second stage desulfurization tower (2) and the third stage desulfurization tower (3) are respectively connected to the slurry circulation pipeline (102); A first-stage slurry nozzle (4) is arranged at the top of the first-stage desulfurization tower (1), and a first-stage slurry collection well (17) is arranged at the bottom of the first-stage desulfurization tower (1); a second-stage slurry nozzle (5) is arranged at the top of the second-stage desulfurization tower (2), and a second-stage slurry collection well (18) is arranged at the bottom of the second-stage desulfurization tower (2); a third-stage slurry nozzle (6) is arranged at the top of the third-stage desulfurization tower (3), and a third-stage slurry collection well (19) is arranged at the bottom of the third-stage desulfurization tower (3); the first-stage slurry nozzle (4), the first-stage slurry collection well (17), the second-stage slurry nozzle (5), the second-stage slurry collection well (18), the third-stage slurry nozzle (6) and the third-stage slurry collection well (19) are respectively connected to the slurry circulation pipeline (102); The slurry circulation pipeline (102) comprises: a first section slurry inlet pipe (12), a second section slurry inlet pipe (13), a third section slurry inlet pipe (14), a desulfurization tower slurry inlet box (21), a gypsum slurry separator (20), a first section slurry discharge pipe (15) and a connecting pipe (22); the first section slurry nozzle (4) is connected to the second section slurry collection well (18) through the first section slurry inlet pipe (12); the second section slurry nozzle (5) is connected to the third section slurry collection well (19) through the second section slurry inlet pipe (13); the third section slurry nozzle (6) is connected to the desulfurization tower slurry inlet box (21) through the third section slurry inlet pipe (14); the desulfurization tower slurry inlet box (21) is connected to the gypsum slurry separator (20) through the connecting pipe (22); and the gypsum slurry separator (20) is connected to the first section slurry collection well (17) through the first section slurry discharge pipe (15); The first section of the slurry inlet pipe (12) is provided with a first section of the slurry inlet pump (7), the second section of the slurry inlet pipe (13) is provided with a second section of the slurry inlet pump (8), the third section of the slurry inlet pipe (14) is provided with a third section of the slurry inlet pump (9), and the first section of the slurry discharge pipe (15) is provided with a first section of the slurry discharge pump (10); The first-stage slurry collection well (17) is provided with a first-stage slurry agitator (24) and a first-stage slurry oxidation fan (27), the second-stage slurry collection well (18) is provided with a second-stage slurry agitator (25) and a second-stage slurry oxidation fan (28), and the third-stage slurry collection well (19) is provided with a third-stage slurry agitator (26) and a third-stage slurry oxidation fan (29).

2. A staged countercurrent boiler flue gas desulfurization device according to claim 1, characterized in that: The desulfurization tower slurry inlet box (21) is provided with a slurry replenishing pipe (23), the gypsum slurry separator (20) is provided with a gypsum slurry discharge pipe (16), and the gypsum slurry discharge pipe (16) is provided with a gypsum slurry discharge pump (11).

3. A desulfurization method for a staged countercurrent boiler flue gas desulfurization device, characterized in that: A segmented countercurrent boiler flue gas desulfurization device according to any one of claims 1-2, the specific steps are as follows: S1: Operation device, the slurry in the desulfurization tower slurry box (21) is ejected from the third-stage slurry nozzle (6) through the third-stage slurry pipe (14) under the action of the third-stage slurry pump (9), the slurry ejected from the third-stage slurry nozzle (6) enters the third-stage slurry collection well (19), the slurry is stirred and oxidized by the third-stage slurry agitator (26) and the third-stage slurry oxidation fan (29), and then ejected from the second-stage slurry nozzle (5) under the action of the second-stage slurry pump (8), the slurry ejected from the second-stage slurry nozzle (5) enters the second-stage slurry collection well (18), the slurry is stirred and oxidized by the second-stage slurry agitator (25) and the second-stage slurry oxidation fan (29), After being stirred and oxidized by the fan (28), the slurry is ejected from the first slurry nozzle (4) under the action of the first slurry inlet pump (7). The slurry ejected from the first slurry nozzle (4) enters the first slurry collection well (17). After being stirred and oxidized by the first slurry agitator (24) and the first slurry oxidation fan (27), the slurry enters the gypsum slurry separator (20) under the action of the first slurry discharge pump (10). The separated secondary use slurry enters the desulfurization tower slurry inlet box (21). The separated solid-liquid mixture is discharged through the gypsum slurry discharge pipe (16) under the action of the gypsum slurry discharge pump (11), thereby achieving slurry circulation; S2: The boiler flue gas is introduced into the raw flue gas inlet port (30), and the boiler flue gas is passed through the first-stage desulfurization tower (1), the second-stage desulfurization tower (2), and the third-stage desulfurization tower (3) in sequence, and the boiler flue gas is mixed with the slurry sprayed from the first-stage slurry nozzle (4), the second-stage slurry nozzle (5), and the third-stage slurry nozzle (6). The slurry removes sulfides in the boiler flue gas and reaches the gypsum slurry separator (20) along the circulation system and is then separated and discharged.

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