Apparatus and method for using iodine to absorb sulfur dioxide in boiler flue gas

Abstract

Disclosed are an apparatus and method for using iodine to absorb sulfur dioxide from boiler flue gas. The apparatus comprises a flue gas inlet, an absorption tower, a filler layer, and a demisting layer. An outlet of the flue gas inlet is connected to an inlet of the absorption tower; the filler layer and the demisting layer are sequentially mounted from bottom to top in the upper portion of the absorption tower; the absorption tower can detect sulfur dioxide; and the filler layer and the demisting layer can resist corrosion of sulfuric acid and hydroiodic acid. In the present method, a sulfur dioxide-containing flue gas is introduced into an absorption tower from a flue gas inlet, and the flue gas is discharged after sequentially passing through a filler layer and a demisting layer. The present invention solves the existing problems in hydrogen production that uses iodine to absorb sulfur dioxide in boiler flue gas.

Description

An apparatus and method for absorbing sulfur dioxide from boiler flue gas using iodine. Technical Field

[0001] This invention belongs to the field of comprehensive utilization of boiler flue gas and hydrogen preparation technology, specifically relating to an apparatus and method for absorbing sulfur dioxide from boiler flue gas using iodine. Background Technology

[0002] Using iodine to absorb sulfur dioxide in flue gas to obtain hydrogen iodide, which is then used to produce hydrogen, achieves waste utilization, environmental protection, and the production of green hydrogen, with good social and economic benefits.

[0003] Iodine is typically used to absorb sulfur dioxide from flue gas using an absorption tower, but this method currently has the following problems:

[0004] (1) Iodine reacts with water and sulfur dioxide to produce sulfuric acid and hydroiodic acid. To separate sulfuric acid and hydroiodic acid, excess iodine needs to be added. Only when the solution density reaches 2.5 kg / L or higher can sulfuric acid and hydroiodic acid separate into layers. This process consumes a large amount of iodine. The diameter of the absorption tower is generally large, and to maintain the normal operation of the slurry circulation pump, a certain liquid level must be maintained, which further increases the iodine consumption.

[0005] (2) Iodine is a relatively volatile substance. Iodine vapor will cause pollution. At the same time, iodine has a high value, and the release of iodine vapor will increase the cost of hydrogen production.

[0006] (3) Absorption and settling cannot be completed in the same absorption tower. Summary of the Invention

[0007] This invention addresses the problems existing in current methods for producing hydrogen from sulfur dioxide in boiler flue gas by absorbing sulfur dioxide, and provides an apparatus and method for absorbing sulfur dioxide in boiler flue gas using iodine.

[0008] This invention is achieved using the following technical solution:

[0009] The present invention provides a device for absorbing sulfur dioxide from boiler flue gas using iodine, comprising a flue gas inlet, an absorption tower, a packing layer, and a demister layer;

[0010] The outlet of the flue gas inlet is connected to the inlet of the absorption tower. The packing layer and the demister layer are installed sequentially from bottom to top in the upper part of the absorption tower. The absorption tower can detect sulfur dioxide, and the packing layer and the demister layer can resist the corrosion of sulfuric acid and hydroiodic acid.

[0011] A further improvement of the present invention is that a flue gas booster fan is installed inside the flue gas inlet. The booster fan is used to increase the flue gas pressure to overcome the resistance of the packing layer and the demister layer.

[0012] A further improvement of the present invention is that it also includes a water adding device and a flue gas discharge device. The water adding device is connected to the upper part of the demister layer through an atomizing nozzle, and the flue gas discharge device is installed at the top of the absorption tower. The flue gas discharge device can detect the sulfur dioxide and iodine content.

[0013] A further improvement of the present invention is that it also includes a slurry collection tank, an iodine absorption layer, a slurry circulation pump, and an iodine addition device. The top of the slurry collection tank is connected to the bottom of the absorption tower. The iodine absorption layer is a fine-pore mesh and is installed on the upper part of the slurry collection tank, on which granular iodine is placed. The outlet of the iodine addition device is connected to the inlet of the iodine absorption layer to provide granular iodine to the iodine absorption layer. The inlet of the slurry circulation pump is connected to the first outlet of the slurry collection tank, and the outlet of the slurry circulation pump is connected between the packing layer and the demister layer through an atomizing nozzle.

[0014] A further improvement of the present invention is that the first outlet of the slurry collection tank is located at its lower part and near the bottom.

[0015] A further improvement of the present invention is that the diameter of the slurry collection tank is smaller than that of the absorption tower, and the amount of slurry that can be stored inside matches the flow rate of the slurry circulation pump, which can meet the normal operation of the slurry circulation pump.

[0016] A further improvement of the present invention is that an absorption tower is equipped with multiple slurry collection tanks, and by switching the slurry collection tanks, the absorption and static stratification of sulfur dioxide can be carried out continuously.

[0017] A further improvement of the present invention is that it also includes a hydrogen iodide solution collection tank, a mixed liquid collection tank, and a sulfuric acid collection tank. The second outlet of the slurry collection tank is located at its bottom and is divided into three streams: the first stream is connected to the inlet of the hydrogen iodide solution collection tank, the second stream is connected to the inlet of the mixed liquid collection tank, and the third stream is connected to the inlet of the sulfuric acid collection tank.

[0018] The present invention also provides a method for absorbing sulfur dioxide from boiler flue gas using iodine, the method being based on the aforementioned apparatus for absorbing sulfur dioxide from boiler flue gas using iodine, comprising:

[0019] Granular iodine is added to the iodine absorption layer using an iodine-adding device;

[0020] Demineralized water is added to the absorption tower through a water adding device. The added demineralized water passes through the demister layer and the packing layer and gathers at the bottom of the absorption tower before flowing into the slurry collection tank. It then passes through the iodine absorption layer and enters the slurry collection tank.

[0021] Once the slurry collection tank reaches the high level, the slurry circulation pump is started to establish slurry circulation. During this process, a small amount of iodine in the iodine absorption layer dissolves.

[0022] Once the slurry circulation pump is running normally and the slurry collection tank level is normal, stop injecting water into the absorption tower.

[0023] Sulfur dioxide-containing flue gas is introduced into the absorption tower through the flue gas inlet, and the flue gas passes through the packing layer and the demister layer before entering the flue gas discharge device.

[0024] When sulfur dioxide in flue gas comes into contact with the mist slurry, it dissolves into water. The water that has absorbed sulfur dioxide passes through the iodine absorption layer and reacts with iodine to produce sulfuric acid and hydroiodic acid.

[0025] As the amount of hydroiodic acid in the slurry increases, the solubility of iodine increases, and the slurry's ability to absorb sulfur dioxide is enhanced. Most of the sulfur dioxide in the flue gas is absorbed. By adjusting the flue gas volume and the circulation volume of the slurry circulation pump, the sulfur dioxide detected by the flue gas discharge device gradually decreases until it meets environmental protection requirements.

[0026] Iodine is replenished to the iodine absorption layer in a timely manner through an iodine-adding device;

[0027] As the circulation absorption proceeds, the density of the slurry in the slurry collection tank increases. When the slurry density reaches or exceeds the set value, the flue gas supply is stopped, and the slurry circulation pump is stopped.

[0028] The slurry in the absorption tower is collected in the slurry collection tank and left to stand until the slurry is clearly separated into layers, with the upper layer being a sulfuric acid solution layer and the lower layer being a mixture of hydroiodic acid and iodine.

[0029] The hydroiodic acid and iodine mixture at the bottom of the slurry collection tank is discharged into the hydrogen iodide solution collection tank;

[0030] The portion of the hydroiodic acid and iodine mixture in contact with the sulfuric acid layer in the middle of the slurry collection tank is discharged into the mixture collection tank;

[0031] Discharge the sulfuric acid solution from the top of the slurry collection tank into the sulfuric acid collection tank;

[0032] The mixed solution in the mixed solution collection tank is added to the slurry collection tank through the iodine addition device, and water is added to the slurry collection tank to the normal water level through the water addition device to start the next absorption.

[0033] A further improvement of the present invention is that the slurry density is set to 2.5 kg / L.

[0034] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0035] The present invention provides a device for absorbing sulfur dioxide in boiler flue gas using iodine, comprising a flue gas inlet, an absorption tower, a packing layer, and a demister layer; flue gas containing sulfur dioxide can be introduced into the absorption tower through the flue gas inlet, and the flue gas is discharged after passing through the packing layer and the demister layer in sequence.

[0036] Furthermore, the flue gas inlet of the present invention is equipped with a flue gas booster fan, which can increase the flue gas pressure and thus overcome the resistance of the packing layer and the demister layer.

[0037] The present invention provides an apparatus for absorbing sulfur dioxide in boiler flue gas using iodine, which further includes a water adding device and a flue gas discharge device. The water adding device can add demineralized water to the absorption tower. The added demineralized water passes through the demister layer and the packing layer and gathers at the bottom of the absorption tower. The flue gas passes through the packing layer and the demister layer and enters the flue gas discharge device. The flue gas discharge device can detect the sulfur dioxide content in the discharged flue gas.

[0038] This invention provides an apparatus for absorbing sulfur dioxide from boiler flue gas using iodine. The apparatus includes a slurry collection tank, an iodine absorption layer, a slurry circulation pump, and an iodine dosing device. The added demineralized water passes through a demister and packing layer, converges at the bottom of the absorption tower, and then flows into the slurry collection tank. It passes through the iodine absorption layer and enters the slurry collection tank, with volatile iodine placed within it to prevent direct contact between iodine and hot flue gas, thus reducing iodine volatilization and escape. The slurry circulation pump circulates the slurry, which passes through the iodine layer formed by iodine particles, reducing the amount of iodine used while ensuring absorption efficiency. The iodine dosing device allows for timely addition of granular iodine to the iodine absorption layer.

[0039] Furthermore, the diameter of the slurry collection tank of the present invention is smaller than that of the absorption tower, and the amount of slurry required to maintain the liquid level of the slurry circulation pump is much smaller than that of a conventional absorption tower, thus greatly reducing the consumption of iodine.

[0040] Furthermore, the present invention configures multiple slurry collection tanks for an absorption tower, and the absorption and static stratification of sulfur dioxide can be continuously carried out by switching the slurry collection tanks.

[0041] The present invention provides an apparatus for absorbing sulfur dioxide from boiler flue gas using iodine, which further includes a hydrogen iodide solution collection tank, a mixed liquid collection tank, and a sulfuric acid collection tank. The hydrogen iodide solution collection tank collects the hydroiodic acid and iodine mixture at the bottom of the slurry collection tank, the mixed liquid collection tank collects the portion of the hydroiodic acid and iodine mixture in contact with the sulfuric acid layer in the middle of the slurry collection tank, and the sulfuric acid collection tank collects the sulfuric acid solution at the top of the slurry collection tank.

[0042] This invention provides a method for absorbing sulfur dioxide from boiler flue gas using iodine. Sulfur dioxide-containing flue gas is introduced into the absorption tower through the flue gas inlet, and then discharged after passing through a packing layer and a demister layer. A water supply device can add demineralized water to the absorption tower. The added demineralized water passes through the demister layer and the packing layer and converges at the bottom of the absorption tower. The flue gas then passes through the packing layer and the demister layer and enters the flue gas discharge device, which monitors the sulfur dioxide content in the discharged flue gas in real time. Placing volatile iodine in a slurry collection tank avoids direct contact between iodine and hot flue gas, reducing iodine volatilization and escape. A slurry circulation pump circulates the slurry, which passes through the iodine layer formed by iodine particles during circulation, reducing the amount of iodine used while ensuring absorption efficiency. Attached Figure Description

[0043] Figure 1 is a structural block diagram of a device for absorbing sulfur dioxide from boiler flue gas using iodine according to the present invention.

[0044] Explanation of reference numerals in the attached figures:

[0045] 1. Flue gas inlet; 2. Absorption tower; 3. Packing layer; 4. Demisting layer; 5. Water addition device; 6. Flue gas discharge device; 7. Slurry collection tank; 8. Iodine absorption layer; 9. Slurry circulation pump; 10. Iodine addition device; 11. Hydrogen iodide solution collection tank; 12. Mixed liquid collection tank; 13. Sulfuric acid collection tank. Detailed Implementation

[0046] Exemplary embodiments of the present disclosure will now be described in more detail with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the disclosure to those skilled in the art. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0047] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0048] Example 1

[0049] As shown in Figure 1, the present invention provides a device for absorbing sulfur dioxide from boiler flue gas using iodine, comprising a flue gas inlet 1, an absorption tower 2, a packing layer 3, and a demister layer 4; the outlet of the flue gas inlet 1 is connected to the inlet of the absorption tower 2, and the packing layer 3 and the demister layer 4 are installed sequentially from bottom to top in the upper part of the absorption tower 2; the absorption tower 2 can detect sulfur dioxide, and the packing layer 3 and the demister layer 4 can resist corrosion from sulfuric acid and hydroiodic acid.

[0050] In this embodiment, a flue gas booster fan is installed inside the flue gas inlet 1. The booster fan can increase the flue gas pressure to overcome the resistance of the packing layer 3 and the demister layer 4. The flue gas containing sulfur dioxide is introduced into the absorption tower 2 through the flue gas inlet 1, and then passes through the packing layer 3 and the demister layer 4 in sequence before being discharged.

[0051] Example 2

[0052] As shown in Figure 1, the present invention provides a device for absorbing sulfur dioxide from boiler flue gas using iodine, comprising a flue gas inlet 1, an absorption tower 2, a packing layer 3, a demister layer 4, a water supply device 5, and a flue gas discharge device 6. The outlet of the flue gas inlet 1 is connected to the inlet of the absorption tower 2. The packing layer 3 and the demister layer 4 are installed sequentially from bottom to top in the upper part of the absorption tower 2. The absorption tower 2 can detect sulfur dioxide, and the packing layer 3 and the demister layer 4 can resist corrosion from sulfuric acid and hydroiodic acid. The water supply device 5 is connected to the upper part of the demister layer 4 through an atomizing nozzle. The flue gas discharge device 6 is installed at the top of the absorption tower 2 and can detect sulfur dioxide and iodine content.

[0053] Example 3

[0054] As shown in Figure 1, the present invention provides a device for absorbing sulfur dioxide from boiler flue gas using iodine, comprising a flue gas inlet 1, an absorption tower 2, a packing layer 3, a demister layer 4, a water supply device 5, a flue gas discharge device 6, a slurry collection tank 7, an iodine absorption layer 8, a slurry circulation pump 9, and an iodine supply device 10. The outlet of the flue gas inlet 1 is connected to the inlet of the absorption tower 2. The packing layer 3 and the demister layer 4 are installed sequentially from bottom to top in the upper part of the absorption tower 2. The absorption tower 2 can detect sulfur dioxide, and the packing layer 3 and the demister layer 4 can resist corrosion from sulfuric acid and hydroiodic acid. The water supply device 5 uses atomized spray... The head is connected to the upper part of the demister layer 4, and the flue gas discharge device 6 is installed at the top of the absorption tower 2. The flue gas discharge device 6 can detect the sulfur dioxide and iodine content. The top of the slurry collection tank 7 is connected to the bottom of the absorption tower 2. The iodine absorption layer 8 is a fine-pore mesh and is installed on the upper part of the slurry collection tank 7. Granular iodine is placed on it. The outlet of the iodine addition device 10 is connected to the inlet of the iodine absorption layer 8 to provide granular iodine to the iodine absorption layer 8. The inlet of the slurry circulation pump 9 is connected to the first outlet of the slurry collection tank 7, and the outlet of the slurry circulation pump 9 is connected between the packing layer 3 and the demister layer 4 through an atomizing nozzle. The slurry collection tank 7 collects volatile iodine, avoiding direct contact between iodine and hot flue gas, reducing iodine volatilization and escape. The slurry circulation pump 9 allows the slurry to pass through the iodine layer formed by iodine particles during circulation, reducing the amount of iodine used while ensuring the absorption effect.

[0055] In this embodiment, the first outlet of the slurry collection tank 7 is located at its lower part and near the bottom, and the diameter of the slurry collection tank 7 is smaller than that of the absorption tower 2. It is made of a fine, transparent material that can resist corrosion by sulfuric acid and hydroiodic acid. The slurry that can be stored inside is matched with the flow rate of the slurry circulation pump 9, which can meet the normal operation of the slurry circulation pump 9.

[0056] In this embodiment, an absorption tower 2 can be configured with multiple slurry collection tanks 7. By switching between different slurry collection tanks 7, the absorption and static stratification of sulfur dioxide can be carried out continuously.

[0057] Example 4

[0058] As shown in Figure 1, the present invention provides a device for absorbing sulfur dioxide from boiler flue gas using iodine, comprising a flue gas inlet 1, an absorption tower 2, a packing layer 3, a demister layer 4, a water supply device 5, a flue gas discharge device 6, a slurry collection tank 7, an iodine absorption layer 8, a slurry circulation pump 9, an iodine supply device 10, a hydrogen iodide solution collection tank 11, a mixed liquid collection tank 12, and a sulfuric acid collection tank 13. The outlet of the flue gas inlet 1 is connected to the inlet of the absorption tower 2. The packing layer 3 and the demister layer 4 are installed sequentially from bottom to top in the upper part of the absorption tower 2. The absorption tower 2 can detect sulfur dioxide, and the packing layer 3 and the demister layer 4 can resist corrosion from sulfuric acid and hydroiodic acid. The water supply device 5 is connected to the upper part of the demister layer 4 through an atomizing nozzle, and the flue gas discharge device 6 is installed in the absorption tower. At the top of 2, the flue gas exhaust device 6 can detect sulfur dioxide and iodine content; the top of the slurry collection tank 7 is connected to the bottom of the absorption tower 2, the iodine absorption layer 8 is a fine mesh and is installed on the upper part of the slurry collection tank 7, on which granular iodine is placed; the outlet of the iodine addition device 10 is connected to the inlet of the iodine absorption layer 8 to provide granular iodine to the iodine absorption layer 8; the inlet of the slurry circulation pump 9 is connected to the first outlet of the slurry collection tank 7, and the outlet of the slurry circulation pump 9 is connected between the packing layer 3 and the demister layer 4 through an atomizing nozzle; the second outlet of the slurry collection tank 7 is at its bottom and is divided into three streams, the first stream is connected to the inlet of the hydrogen iodide solution collection tank 11, the second stream is connected to the inlet of the mixed liquid collection tank 12, and the third stream is connected to the inlet of the sulfuric acid collection tank 13. The hydrogen iodide solution collection tank 11 is used to collect the hydroiodic acid and iodine mixture in the lower part of the slurry collection tank 7, the mixture collection tank 12 is used to collect the part of the hydroiodic acid and iodine mixture in the middle of the slurry collection tank 7 that is in contact with the sulfuric acid layer, and the sulfuric acid collection tank 13 is used to collect the sulfuric acid solution in the upper part of the liquid collection tank 7.

[0059] Example 5

[0060] This invention provides a method for absorbing sulfur dioxide from boiler flue gas using iodine. The method is based on a system for absorbing sulfur dioxide from boiler flue gas using iodine, as shown in Figure 1. This system includes a flue gas inlet 1, an absorption tower 2, a packing layer 3, a demister layer 4, a water addition device 5, a flue gas discharge device 6, a slurry collection tank 7, an iodine absorption layer 8, a slurry circulation pump 9, an iodine addition device 10, a hydrogen iodide solution collection tank 11, a mixed liquid collection tank 12, and a sulfuric acid collection tank 13. The outlet of the flue gas inlet 1 is connected to the inlet of the absorption tower 2. The packing layer 3 and the demister layer 4 are installed sequentially from bottom to top in the upper part of the absorption tower 2. The absorption tower 2 can detect sulfur dioxide, and the packing layer 3 and the demister layer 4 can resist the corrosion of sulfuric acid and hydroiodic acid. The water adding device 5 is connected to the upper part of the demister layer 4 through an atomizing nozzle. The flue gas exhaust device 6 is installed at the top of the absorption tower 2. The flue gas exhaust device 6 can detect sulfur dioxide and iodine content. The top of the slurry collection tank 7 is connected to the bottom of the absorption tower 2. The iodine absorption layer 8 is a fine-pore mesh and is installed on the upper part of the slurry collection tank 7. Granular iodine is placed on top of it. The outlet of the iodine addition device 10 is connected to the inlet of the iodine absorption layer 8 to provide granular iodine to the iodine absorption layer 8. The inlet of the slurry circulation pump 9 is connected to the first outlet of the slurry collection tank 7. The outlet of the slurry circulation pump 9 is connected between the packing layer 3 and the demisting layer 4 through an atomizing nozzle. The second outlet of the slurry collection tank 7 is at its bottom and is divided into three streams. The first stream is connected to the inlet of the hydrogen iodide solution collection tank 11, the second stream is connected to the inlet of the mixed liquid collection tank 12, and the third stream is connected to the inlet of the sulfuric acid collection tank 13.

[0061] The method includes:

[0062] Granular iodine is added to the iodine absorption layer 8 through the iodine addition device 10;

[0063] Demineralized water is added to the absorption tower 2 through the water adding device 5. The added demineralized water flows into the slurry collection tank 7 after passing through the demisting layer 4 and the packing layer 3 and converging at the bottom of the absorption tower 2. It then passes through the iodine absorption layer 8 and enters the slurry collection tank 7.

[0064] When the slurry collection tank 7 reaches the high liquid level, the slurry circulation pump 9 is started to establish slurry circulation. During this process, a small amount of iodine in the iodine absorption layer 8 dissolves.

[0065] Once the slurry circulation pump is running normally and the liquid level in the slurry collection tank 7 is normal, stop injecting water into the absorption tower 2.

[0066] Sulfur dioxide-containing flue gas is introduced into the absorption tower 2 through the flue gas inlet 1. The flue gas passes through the packing layer 3 and the demister layer 4 and enters the flue gas discharge device 6.

[0067] When sulfur dioxide in flue gas comes into contact with the mist slurry, it dissolves into water. The water that has absorbed sulfur dioxide passes through the iodine absorption layer 8 and reacts chemically with iodine to produce sulfuric acid and hydroiodic acid.

[0068] As the amount of hydroiodic acid in the slurry increases, the dissolution of iodine increases, and the slurry's ability to absorb sulfur dioxide is enhanced. Most of the sulfur dioxide in the flue gas is absorbed. By adjusting the flue gas volume and the circulation volume of the slurry circulation pump, the sulfur dioxide detected by the flue gas discharge device 6 gradually decreases until it meets environmental protection requirements.

[0069] Iodine is replenished to the iodine absorption layer 8 in a timely manner through the iodine addition device 10;

[0070] As the circulation absorption proceeds, the density of the slurry in the slurry collection tank 7 increases. When the slurry density reaches 2.5 kg / L or higher, the flue gas is stopped and the slurry circulation pump 9 is stopped.

[0071] The slurry in the absorption tower 2 is collected in the slurry collection tank 7 and left to stand until the slurry is clearly separated into layers, with the upper layer being a sulfuric acid solution layer and the lower layer being a mixture of hydroiodic acid and iodine.

[0072] The hydroiodic acid and iodine mixture at the bottom of the slurry collection tank 7 is discharged into the hydrogen iodide solution collection tank 11;

[0073] The portion of the hydroiodic acid and iodine mixture in contact with the sulfuric acid layer in the middle of the slurry collection tank 7 is discharged into the mixture collection tank 12;

[0074] The sulfuric acid solution in the upper part of the slurry collection tank 7 is discharged into the sulfuric acid collection tank 13;

[0075] The mixed solution in the mixed solution collection tank 12 is added to the slurry collection tank 7 through the iodine addition device, and water is added to the slurry collection tank 7 through the water addition device 5 to bring it to the normal water level before the next absorption begins.

[0076] Example 6

[0077] As shown in Figure 1, in this embodiment, an absorption tower 2 with a diameter of 2 meters is used. To maintain the normal operation of the slurry circulation pump, a liquid level of 1 meter must be maintained, requiring a slurry volume of approximately 3 m³. 3 Absorption and settling separation cannot be achieved simultaneously, making continuous production impossible.

[0078] Using the method of this invention, the absorption tower 2 has a diameter of 2 meters, and two slurry absorption tanks 7, each with a diameter of 0.5 meters, are used. The slurry level is 1 meter, and the required slurry volume for a single absorption tank is approximately 0.2 m³. 3 The amount of iodine used in a single absorption tank is 7% of the normal usage, but this does not affect the normal operation of the slurry circulation pump 9. Two slurry absorption tanks 7 are set up, one for absorption and one for settling and separation, enabling continuous production.

[0079] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A device for absorbing boiler flue gas sulfur dioxide by iodine, characterized in that, The device comprises a flue gas inlet (1), an absorption tower (2), a filler layer (3), a demisting layer (4), a water adding device (5), a flue gas outlet device (6), a slurry collecting tank (7), an iodine absorption layer (8), a slurry circulating pump (9) and an iodine adding device (10). The outlet of the flue gas inlet (1) is connected to the inlet of the absorption tower (2), the filler layer (3) and the demisting layer (4) are sequentially installed in the upper part of the absorption tower (2) from bottom to top, the absorption tower (2) can detect sulfur dioxide, and the filler layer (3) and the demisting layer (4) can resist corrosion of sulfuric acid and hydroiodic acid. The water adding device (5) is connected to the upper part of the demisting layer (4) through a misting nozzle, and the flue gas outlet device (6) is installed at the top of the absorption tower (2), which can detect sulfur dioxide and iodine content. The top of the slurry collecting tank (7) is connected to the bottom of the absorption tower (2), the iodine absorption layer (8) is a fine mesh network, which is installed in the upper part of the slurry collecting tank (7), and granular iodine is placed on it, the outlet of the iodine adding device (10) is connected to the inlet of the iodine absorption layer (8), which provides granular iodine for the iodine absorption layer (8), and the inlet of the slurry circulating pump (9) is connected to the first outlet of the slurry collecting tank (7), and the outlet of the slurry circulating pump (9) is connected to the filler layer (3) and the demisting layer (4) through a misting nozzle.

2. A device for absorbing sulfur dioxide of boiler flue gas by iodine according to claim 1, characterized in that, A flue gas booster fan is installed in the flue gas inlet (1), which is used to increase the flue gas pressure to overcome the resistance of the filler layer (3) and the demisting layer (4).

3. A device for absorbing sulfur dioxide of boiler flue gas by iodine according to claim 1, characterized in that, The first outlet of the slurry collecting tank (7) is arranged at the lower part close to the bottom.

4. A device for absorbing sulfur dioxide of boiler flue gas by iodine according to claim 1, characterized in that, The diameter of the slurry collecting tank (7) is smaller than that of the absorption tower (2), and the internal capacity of the slurry collecting tank (7) matches the flow rate of the slurry circulating pump (9), which can meet the normal operation of the slurry circulating pump (9).

5. A device for absorbing sulfur dioxide of boiler flue gas by iodine according to claim 1, characterized in that, One absorption tower (2) is provided with multiple slurry collecting tanks (7), and the absorption of sulfur dioxide and the static stratification and continuous operation can be realized by switching the slurry collecting tanks (7).

6. A device for absorbing sulfur dioxide of boiler flue gas by iodine according to claim 1, characterized in that, It also comprises a hydrogen iodide solution collecting tank (11), a mixed liquid collecting tank (12) and a sulfuric acid collecting tank (13), the second outlet of the slurry collecting tank (7) is arranged at the bottom thereof and is divided into three streams, the first stream is connected to the inlet of the hydrogen iodide solution collecting tank (11), the second stream is connected to the inlet of the mixed liquid collecting tank (12), and the third stream is connected to the inlet of the sulfuric acid collecting tank (13).

7. A method of absorbing boiler flue gas sulfur dioxide with iodine, characterized by, The method is based on the device for absorbing sulfur dioxide in boiler flue gas by using iodine in claim 6, comprising: granular iodine is added to the iodine absorption layer (8) through the iodine adding device (10); salt-free water is added to the absorption tower (2) through the water adding device (5), and the added salt-free water passes through the demisting layer (4) and the filler layer (3) to gather at the bottom of the absorption tower (2), and then flows into the slurry collecting tank (7) and passes through the iodine absorption layer (8) into the slurry collecting tank (7); when the slurry collecting tank (7) reaches a high liquid level, the slurry circulating pump (9) is started to establish a slurry circulation, and in this process, a small amount of iodine in the iodine absorption layer (8) is dissolved; when the slurry circulating pump operates normally and the liquid level of the slurry collecting tank (7) is normal, the water injection to the absorption tower (2) is stopped; The flue gas containing sulfur dioxide is introduced into the absorption tower (2) through the flue gas inlet (1), and the flue gas passes through the filler layer (3) and the demisting layer (4) to enter the flue gas discharge device (6); The sulfur dioxide in the flue gas dissolves into water after contacting with the foggy slurry, and the water absorbing sulfur dioxide reacts with iodine after passing through the iodine absorption layer (8) to generate sulfuric acid and hydroiodic acid; With the increase of hydroiodic acid in the slurry, the dissolution of iodine increases, the absorption capacity of the slurry for sulfur dioxide increases, and most of the sulfur dioxide in the flue gas is absorbed, the amount of flue gas and the circulating amount of the slurry circulating pump are adjusted, the sulfur dioxide detected by the flue gas discharge device (6) gradually decreases until the environmental protection requirement is reached; The iodine is supplemented to the iodine absorption layer (8) in time through the iodine adding device (10); With the circulation of the absorption, the slurry density in the slurry collection tank (7) becomes higher and higher, when the slurry density reaches the set value, the flue gas is stopped, and the slurry circulating pump (9) is stopped; The slurry in the absorption tower (2) is collected in the slurry collection tank (7), and is left to stand until the slurry is obviously stratified, the upper part is a sulfuric acid solution layer, and the lower part is a hydroiodic acid and iodine mixed solution layer; The hydroiodic acid and iodine mixed solution in the lower part of the slurry collection tank (7) is discharged to the hydrogen iodide solution collection tank (11); The hydroiodic acid and iodine mixed solution in the middle part of the slurry collection tank (7) is discharged to the mixed solution collection tank (12); The sulfuric acid solution in the upper part of the slurry collection tank (7) is discharged to the sulfuric acid collection tank (13); The mixed solution in the mixed solution collection tank (12) is added to the slurry collection tank (7) through the iodine adding device, and water is supplemented to the slurry collection tank (7) to the normal water level through the water adding device (5) to start the next absorption.

8. A method of absorbing boiler flue gas sulfur dioxide with iodine according to claim 7, characterized in that, The set value of the slurry density is 2.5 kg / L.

Images