Tail gas treatment system

Abstract

The utility model belongs to the technical field of tail gas treatment, and particularly relates to a tail gas treatment system which comprises a first absorption tower system, a second absorption tower system and a third absorption tower system, a first liquid inlet, a first tail gas inlet, a first liquid outlet and a first tail gas outlet are formed in the first absorption tower; the first spraying device is connected with the first liquid outlet through a first pipeline, and a first conveying pump and a first control valve are arranged on the first pipeline; the first spraying liquid output pipe is communicated with the first pipeline, and a first output control valve is arranged on the first spraying liquid output pipe. The tail gas treatment system provided by the utility model is internally provided with a three-stage absorption tower system, so that the absorption efficiency of hydrogen sulfide is far higher than that of the traditional single-stage alkali liquor absorption, and the up-to-standard emission of the absorbed hydrogen sulfide tail gas can be ensured.

Description

Technical Field

[0001] This utility model belongs to the field of exhaust gas treatment technology, and specifically relates to an exhaust gas treatment system. Background Technology

[0002] Sulfide treatment technology is highly efficient in treating acidic wastewater containing heavy metals in production practice. The extremely low solubility product constant of heavy metal sulfides ensures that heavy metal ions in the wastewater can precipitate as sulfides under acidic conditions, thereby removing heavy metals from the wastewater. However, in an acidic environment, sodium sulfide ions combine with hydrogen ions to produce hydrogen sulfide gas as a byproduct. The reaction equation is as follows:

[0003] H₂SO₄ + Na₂S = H₂S↑ + Na₂SO₄

[0004] Hydrogen sulfide is a highly toxic and flammable hazardous substance. Its emission limits are strictly defined in the "Odor Pollutant Emission Standard" (GB14554-93). The absorption efficiency of hydrogen sulfide tail gas directly affects whether the exhaust gas from the sulfidation technology used to treat heavy metal-containing acidic wastewater can meet emission standards.

[0005] Traditional hydrogen sulfide absorption processes use sodium hydroxide spraying within the absorption tower, resulting in low mass transfer efficiency and poor reaction performance. In particular, when the absorbent is saturated and requires alkali replacement, the addition of fresh sodium hydroxide solution is often delayed, frequently leading to excessive levels of hydrogen sulfide gas. Utility Model Content

[0006] To address the problems existing in the prior art, this utility model provides an exhaust gas treatment system, which specifically includes the following:

[0007] An exhaust gas treatment system includes a first absorption tower system, a second absorption tower system, and a third absorption tower system;

[0008] The first absorption tower system includes a first absorption tower, a first spray device, and a first spray liquid output pipe. The first absorption tower is provided with a first liquid inlet, a first tail gas inlet, a first liquid outlet, and a first tail gas outlet. The first spray device is connected to the first liquid outlet through a first pipeline, and a first delivery pump and a first control valve are provided on the first pipeline. The first spray liquid output pipe is connected to the first pipeline, and a first output control valve is provided on the first spray liquid output pipe.

[0009] The second absorption tower system includes a second absorption tower, a second spray device, and a second spray liquid output pipe. The second absorption tower is provided with a second liquid inlet, a second tail gas inlet, a second liquid outlet, and a second tail gas outlet. The second tail gas inlet is connected to the first tail gas outlet. The second spray device is connected to the second liquid outlet through a second pipeline, and a second delivery pump and a second control valve are provided on the second pipeline. The second spray liquid output pipe is connected to the second pipeline, and a second output control valve is provided on the second spray liquid output pipe.

[0010] The third absorption tower system includes a third absorption tower, a third spray device, and a third spray liquid output pipe. The third absorption tower is provided with a third liquid inlet, a third tail gas inlet, a third liquid outlet, and a third tail gas outlet. The third tail gas inlet is connected to the second tail gas outlet. The third spray device is connected to the third liquid outlet through a third pipeline, and the third pipeline is provided with a third delivery pump and a third control valve. One end of the third spray liquid output pipe is connected to the third pipeline, and the other end is connected to the second liquid inlet. The third spray liquid output pipe is provided with a third output control valve.

[0011] Furthermore, the first absorption tower system also includes a first liquid level detection device, which is installed on the first absorption tower and is signal-connected to the first output control valve; and / or, the first output control valve is an automatic control valve; and / or,

[0012] The first liquid inlet and the first exhaust gas inlet are disposed on the side wall of the first absorption tower, and the first liquid inlet is located above the first exhaust gas inlet; and / or, the first exhaust gas outlet is disposed at the top of the first absorption tower, and the first spray device is disposed at the upper part of the first absorption tower.

[0013] Furthermore, the second absorption tower system also includes a second liquid level detection device, which is installed on the second absorption tower and is signal-connected to the second output control valve; and / or, the second output control valve is an automatic control valve; and / or,

[0014] The second absorption tower is a packed tower; the second absorption tower includes a spray section, a packing section and a hollow section from top to bottom, and the second tail gas inlet, the second liquid outlet and the second liquid outlet are all located in the hollow section; the second spray device is located in the spray section; the second tail gas outlet is located at the top of the second absorption tower.

[0015] Furthermore, the second absorption tower system also includes a second absorption tower precipitator, which is disposed above the second spray device and below the second exhaust gas outlet. Preferably, the second absorption tower precipitator is a precipitator mesh laid above the second spray device and covering the cross-section of the second absorption tower.

[0016] Furthermore, the third absorption tower system also includes a third liquid level detection device, which is installed on the third absorption tower and is signal-connected to its corresponding third output control valve; and / or, the third output control valve is an automatic control valve; and / or,

[0017] The third exhaust gas inlet is connected to the second exhaust gas outlet via a gas pipeline, and a fan is installed on the gas pipeline; a drain pipe is also connected to the third pipeline, and a drain valve is installed on the drain pipe; and / or,

[0018] The third absorption tower is a packed tower; the third absorption tower includes a spray section, a packing section, and a hollow section from top to bottom; the third tail gas inlet, the third liquid outlet, and the third liquid outlet are all located in the hollow section; the third spray device is located in the spray section; the third tail gas outlet is located at the top of the third absorption tower; and / or,

[0019] The third absorption tower system also includes a third absorption tower pH meter installed at the bottom of the third absorption tower, and the pH meter must be submerged in the absorption liquid at the bottom of the third absorption tower.

[0020] Furthermore, the third absorption tower system also includes a third absorption tower water absorber and a third absorption tower mist eliminator. The third absorption tower water absorber is positioned above the third spray device; the second absorption tower mist eliminator is positioned above the third absorption tower water absorber and below the third exhaust gas outlet. Preferably, the third absorption tower mist eliminator is a mist eliminator mesh laid above the third spray device and covering the cross-section of the third absorption tower.

[0021] Furthermore, it also includes an absorbent storage tank, which is connected to the third liquid inlet via a delivery pipe, and the delivery pipe is equipped with a delivery control valve.

[0022] Furthermore, it also includes an online exhaust gas analyzer, the input end of which is connected to the third exhaust gas outlet, and the output end of which is connected to the delivery control valve signal.

[0023] Furthermore, the third absorption tower system also includes a tail gas chimney, which is located above the third tail gas outlet and its bottom end is connected to the third tail gas outlet; the input end of the tail gas online analysis device is located inside the tail gas chimney.

[0024] A method for treating hydrogen sulfide-containing exhaust gas using the exhaust gas treatment system described above utilizes a three-stage absorption tower in the system to absorb the hydrogen sulfide-containing exhaust gas.

[0025] In the primary absorption tower (i.e., the first absorption tower), the heavy metal-containing acidic wastewater is used as the scrubbing liquid and is counter-currently absorbed with hydrogen sulfide tail gas. The hydrogen sulfide gas reacts with the heavy metals in the acidic wastewater, which not only consumes a large amount of hydrogen sulfide in the tail gas, but also pre-treats the acidic wastewater, initially reducing the concentration of heavy metals in the acidic wastewater. The reaction equation is as follows:

[0026] 2AsO 2- +2S 2- +8H + =As2S3↓+4H2O

[0027] 2AsO4 3+ +5S 2- +16H + =As2S5↓+8H2O

[0028] Cu 2+ +S 2- =CuS↓

[0029] Pb 2+ +S 2- =PbS↓

[0030] Ni 2+ +S 2- =NiS↓

[0031] In the secondary absorption tower (i.e., the second absorption tower), the sodium sulfide solution produced after absorption by the tertiary absorption tower (i.e., the third absorption tower) is introduced into the second absorption tower as the absorbent. Hydrogen sulfide tail gas is then sprayed into the second absorption tower for absorption. The main reactions are as follows:

[0032] Na₂S + H₂S = 2NaHS

[0033] The sodium hydrosulfide solution absorbed by the secondary absorption tower can be used as a sulfiding agent in the sulfidation reaction process of heavy metal-containing acidic wastewater and recycled in the sulfidation reactor.

[0034] In the three-stage absorption tower (i.e., the third absorption tower), after the first two stages of absorption, the hydrogen sulfide concentration in the exhaust gas has been greatly reduced. The exhaust gas is then transported to the third absorption tower by a fan. The third absorption tower is a packed tower with at least one (preferably two) packing layer. It is absorbed by spraying with a prepared sodium hydroxide solution (preferably with a mass concentration of 10%), with gas and liquid in counter-current contact. The low-concentration hydrogen sulfide gas is further absorbed, and finally, it meets the emission standards. The three-stage absorption tower has an integrated tower and chimney structure. The top of the tower is evenly distributed with liquid distribution pipes, and a layer of mist-catching wire mesh is installed on the top of the pipes to capture the mist droplets in the absorbed exhaust gas before it is discharged through the chimney.

[0035] The main reaction equations in the three-stage absorption tower are as follows:

[0036] H₂S + NaOH = Na₂S + H₂O

[0037] The sodium sulfide solution generated from the reaction is sent to the secondary absorption tower as the secondary circulating absorbent.

[0038] The beneficial effects of this utility model are:

[0039] The exhaust gas treatment system provided by this invention features a three-stage absorption tower system. Its absorption efficiency for hydrogen sulfide is far greater than that of traditional single-stage alkaline absorption, ensuring that the hydrogen sulfide exhaust gas meets emission standards after absorption. Simultaneously, the first-stage hydrogen sulfide absorption serves as a pretreatment for acidic wastewater, utilizing the byproduct hydrogen sulfide gas to initially reduce heavy metal concentrations before the formal sulfidation reaction of the acidic wastewater. This both absorbs the exhaust gas and reduces the production load of the sulfidation reaction section. The second-stage hydrogen sulfide absorption tower uses the sodium sulfide solution produced in the third-stage absorption as the absorbent. After complete absorption, the resulting sodium hydrosulfide solution is sent to the sulfidation reactor as a sulfiding agent. The third-stage hydrogen sulfide absorption tower uses sodium hydroxide as the absorbent, serving as a safety absorption for the entire system to ensure that the exhaust gas meets emission standards. The three-stage absorption tower series absorption device for hydrogen sulfide maximizes the effective utilization of sulfur in the by-product hydrogen sulfide produced during the sulfidation reaction. It maximizes the introduction of enriched sulfur into the sulfidation reactor to react with heavy metals in the wastewater, significantly improving the sulfidation efficiency while greatly reducing the amount of alkali solution used for hydrogen sulfide absorption. This system improves both tail gas absorption efficiency, ensuring waste discharge meets standards, and sulfidation reaction efficiency, ensuring maximum reaction between sulfur in the sulfiding agent and heavy metals.

[0040] Meanwhile, the fan (environmental protection fan) is placed between the second-stage absorption tower and the third-stage absorption tower to ensure that the first-stage and second-stage absorption systems, which have relatively high hydrogen sulfide concentrations, are under negative pressure. Even if leaks occur in the pipelines due to equipment aging, hydrogen sulfide can still be prevented from leaking into the environment and polluting the air under negative pressure. Attached Figure Description

[0041] Figure 1This is a schematic diagram of the exhaust gas treatment system disclosed in this utility model. Detailed Implementation

[0042] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. The embodiments shown below do not limit the scope of the utility model as described in the claims. Furthermore, the complete contents of the configurations shown in the following embodiments are not limited to those necessary for the solution of the utility model as described in the claims.

[0043] Reference Appendix Figure 1 A tail gas treatment system includes a first absorption tower system, a second absorption tower system, and a third absorption tower system. The first absorption tower system includes a first absorption tower 1, a first spray device 15, and a first spray liquid output pipe 18. The first absorption tower 1 is provided with a first liquid inlet 14, a first tail gas inlet 13, a first liquid outlet, and a first tail gas outlet 16. The first spray device 15 is connected to the first liquid outlet via a first pipeline, and the first pipeline is provided with a first delivery pump 11 and a first control valve. The first spray liquid output pipe 18 is connected to the first pipeline, and the first spray liquid output pipe 18 is provided with a first output control valve 121. The second absorption tower system includes a second absorption tower 2, a second spray device 25, and a second spray liquid output pipe 28. The second absorption tower 2 is provided with a second liquid inlet 23, a second tail gas inlet 22, a second liquid outlet, and a second tail gas outlet. The second tail gas inlet 22 and the first tail gas outlet 16 are connected via a pipe... The system is connected to the second liquid outlet via a second pipeline, which is equipped with a second delivery pump 21 and a second control valve. The second spray liquid output pipe 28 is connected to the second pipeline, and a second output control valve 291 is installed on the second spray liquid output pipe 28. The third absorption tower system includes a third absorption tower 3, a third spray device 34, and a third spray liquid output pipe. The third absorption tower 3 is equipped with a third liquid inlet 33, a third tail gas inlet 32, a third liquid outlet, and a third tail gas outlet. The third tail gas inlet 32 ​​is connected to the second tail gas outlet. The third spray device 34 is connected to the third liquid outlet via a third pipeline, which is equipped with a third delivery pump 31 and a third control valve. One end of the third spray liquid output pipe 39 is connected to the third pipeline, and the other end is connected to the second liquid inlet 23. A third output control valve 391 is installed on the third spray liquid output pipe 39.

[0044] In some embodiments of this utility model, the first absorption tower system further includes a first liquid level detection device 12, which is disposed on the first absorption tower 1 and is signal-connected to the first output control valve 121; preferably, the first output control valve 121 is an automatic control valve; preferably, the first liquid inlet 14 and the first tail gas inlet 13 are disposed on the side wall of the first absorption tower 1, and the first liquid inlet 14 is located above the first tail gas inlet 13; preferably, the first tail gas outlet 16 is disposed at the top of the first absorption tower 1, and the first spray device 15 is disposed at the upper part of the first absorption tower 1.

[0045] In some embodiments of this utility model, the second absorption tower system further includes a second liquid level detection device 29, which is disposed on the second absorption tower 2 and is signal-connected to the second output control valve 291; preferably, the second output control valve 291 is an automatic control valve; preferably, the second absorption tower 2 is a packed tower; the second absorption tower 2 includes a spray section, a packing section and a hollow section from top to bottom, and the second tail gas inlet 22, the second liquid outlet and the second liquid inlet 23 are all disposed in the hollow section; the second spray device 25 is disposed in the spray section; the second tail gas outlet is disposed at the top of the second absorption tower 2.

[0046] In some embodiments of this utility model, the second absorption tower system further includes a second absorption tower demister 26, which is disposed above the second spray device 25 and below the second exhaust gas outlet. Preferably, the second absorption tower demister 26 is a demister mesh laid above the second spray device 25 and covering the cross-section of the second absorption tower 2.

[0047] In some embodiments of this utility model, the third absorption tower system further includes a third liquid level detection device 392, which is disposed on the third absorption tower 3 and is signal-connected to its corresponding third output control valve 391; preferably, the third output control valve 391 is an automatic control valve; preferably, the third tail gas inlet 32 ​​is connected to the second tail gas outlet through a gas pipeline, and a fan 4 is disposed on the gas pipeline; a drain pipe 41 is also connected to the third pipeline, and a drain valve is disposed on the drain pipe 41; preferably, the third absorption tower 3 is a packed tower; the third absorption tower 3 includes a spray section, a packing section and a hollow section from top to bottom, and the third tail gas inlet 32, the third liquid outlet and the third liquid inlet 33 are all disposed in the hollow section; the third spray device 34 is disposed in the spray section; and the third tail gas outlet is disposed at the top of the third absorption tower 3.

[0048] In some embodiments of this utility model, the third absorption tower system further includes a third absorption tower pH meter 38 disposed at the lower part of the third absorption tower 3, and the third absorption tower pH meter 38 shall be ensured to be immersed in the absorption liquid at the bottom of the third absorption tower 3.

[0049] In some embodiments of this utility model, the third absorption tower system further includes a third absorption tower water absorber 361 and a third absorption tower mist eliminator 36. The third absorption tower water absorber 361 is disposed above the third spray device 34; the second absorption tower mist eliminator 26 is disposed above the third absorption tower water absorber 361 and located below the third exhaust gas outlet. Preferably, the third absorption tower mist eliminator 36 is a mist eliminator mesh laid above the third spray device 34 and covering the cross-section of the third absorption tower 3.

[0050] In some embodiments of this utility model, an absorbent storage tank 5 is also included. The absorbent storage tank 5 is connected to the third liquid inlet 33 via a conveying pipe, and a conveying control valve 51 is provided on the conveying pipe. Preferably, the absorbent storage tank 5 is a high-level tank, which can use gravity to convey the absorbent to the third absorption tower 3.

[0051] In some embodiments of this utility model, an online exhaust gas analyzer 371 is also included. The input end of the online exhaust gas analyzer 371 is connected to the third exhaust gas outlet, and the output end of the online exhaust gas analyzer 371 is signal-connected to the delivery control valve 51.

[0052] In some embodiments of this utility model, the third absorption tower system further includes a tail gas chimney 37, which is disposed above the third tail gas outlet and its bottom end is connected to the third tail gas outlet; the input end of the tail gas online analysis device 371 is disposed inside the tail gas chimney 37.

[0053] A method for treating hydrogen sulfide-containing exhaust gas using the aforementioned exhaust gas treatment system utilizes a three-stage absorption tower in the system to absorb the hydrogen sulfide-containing exhaust gas, wherein:

[0054] In the primary absorption tower (i.e., the first absorption tower 1), the wastewater containing heavy metals is used as the scrubbing liquid and is counter-currently absorbed with the hydrogen sulfide tail gas. The hydrogen sulfide gas reacts with the heavy metals in the wastewater, which not only consumes a large amount of hydrogen sulfide in the tail gas, but also pre-treats the wastewater, initially reducing the concentration of heavy metals in the wastewater. The reaction equation is as follows:

[0055] 2AsO 2- +2S 2- +8H + =As2S3↓+4H2O

[0056] 2AsO4 3+ +5S 2- +16H + =As2S5↓+8H2O

[0057] Cu 2+ +S 2- =CuS↓

[0058] Pb 2+ +S 2- =PbS↓

[0059] Ni 2+ +S 2- =NiS↓

[0060] In the secondary absorption tower (i.e., the second absorption tower 2), the sodium sulfide solution produced after absorption by the tertiary absorption tower (i.e., the third absorption tower 3) is introduced into the second absorption tower 2 as the absorbent. Hydrogen sulfide tail gas is then sprayed into the second absorption tower 2 for absorption. The main reactions are as follows:

[0061] Na₂S + H₂S = 2NaHS

[0062] The sodium hydrosulfide solution absorbed by the secondary absorption tower can be used as a sulfiding agent in the sulfidation reaction process of heavy metal-containing acidic wastewater and recycled in the sulfidation reactor.

[0063] In the three-stage absorption tower (i.e., the third absorption tower 3), after the first two stages of absorption, the concentration of hydrogen sulfide in the exhaust gas has been greatly reduced. The exhaust gas is then transported to the third absorption tower 3 by the fan 4. The third absorption tower 3 is a packed tower with at least one (preferably two) packing layer. It is absorbed by spraying with a prepared sodium hydroxide solution (preferably with a mass concentration of 10%), with gas and liquid in counter-current contact. The low concentration of hydrogen sulfide gas is further absorbed, and finally, it meets the emission standards. The three-stage absorption tower has an integrated tower and chimney structure. The top of the tower is evenly distributed with liquid distribution pipes, and a layer of mist-catching wire mesh is installed on the top of the pipes to capture the mist droplets in the absorbed exhaust gas and discharge it through the chimney.

[0064] The main reaction equations in the three-stage absorption tower are as follows:

[0065] H₂S + NaOH = Na₂S + H₂O

[0066] The sodium sulfide solution generated from the reaction is sent to the secondary absorption tower as the secondary circulating absorbent.

[0067] The exhaust gas treatment system disclosed in this utility model, when actually used to treat exhaust gas containing hydrogen sulfide, involves the hydrogen sulfide gas generated by the sulfidation unit reaction being collected by an exhaust gas collection device into a main exhaust gas pipeline. This main pipeline is connected to the first exhaust gas inlet 13 of the first absorption tower 1. The first exhaust gas inlet 13 is positioned above the circulating liquid level in the first absorption tower 1. The hydrogen sulfide exhaust gas is counter-currently sprayed and absorbed by the waste acid from the acid water equalization tank within the first absorption tower 1. A first liquid inlet 14 is positioned above the first exhaust gas inlet 13. A first transfer pump 11 is connected to the lower part of the first absorption tower 1. During normal production, the waste acid from the outlet of the first transfer pump 11 is transported as circulating absorbent to the upper part of the first absorption tower 1, where it is sprayed and absorbed by the first spray device 15. The remaining portion is transported to the sulfidation reaction unit for sulfidation reaction through the first spray liquid output pipe 18.

[0068] The hydrogen sulfide tail gas absorbed by the first absorption tower 1 is sent to the second absorption tower 2 through the first tail gas outlet 16. The second absorption tower 2 is a packed tower, and the second tail gas inlet 22 is located between the upper part of the liquid surface of the circulating liquid in the second absorption tower 2 and the lower part of the packing layer of the second absorption tower 2. The hydrogen sulfide waste gas is absorbed by counter-current contact with the absorbent sprayed from top to bottom. The absorbent is sent to the second spray device 25 at the top of the tower by the second transfer pump 21 for spray absorption. The sodium hydrosulfide solution generated by the absorption of the second absorption tower 2 is sent to the sulfidation reaction unit for sulfidation reaction through the second spray liquid output pipe 28. After absorption, the waste gas passes through the second absorption tower mist eliminator 26 to capture acid mist and is then sent to the tail gas fan 4 through the gas pipeline. To prevent the hydrogen sulfide waste gas water mist at the outlet of the second absorption tower 2 from entering the tail gas fan 4 due to insufficient capture, the pre-drainage of the fan 4 is turned on once per shift during production.

[0069] After two stages of absorption, the hydrogen sulfide waste gas is pressurized by the exhaust gas fan 4 and then sent to the third absorption tower 3. The third absorption tower 3 is a packed tower. The third exhaust gas inlet 32 ​​of the third absorption tower 3 is located between the absorbent liquid surface and the packing of the third absorption tower 3, and absorbs in the opposite direction to the absorbent liquid sprayed from top to bottom. The absorbent liquid is sent to the third spray device 34 at the top of the tower for circulation absorption by the third transfer pump 31. After absorption in the tower, the exhaust gas passes through the water collector and the mist eliminator 36 at the top of the third absorption tower 3 to capture water mist before being discharged through the exhaust gas chimney 37 in compliance with emission standards.

[0070] When the absorbent solution approaches saturation and the absorption efficiency decreases, the concentration of hydrogen sulfide in the online analyzer reaches the set value. The interlocking control valve opens, and the liquid level in the third absorption tower 3 continues to rise. When the liquid level exceeds the set value of the third liquid level detection device 392, the interlocking control valve 391 opens, sending the absorbent solution with lower alkali content from the bottom of the third absorption tower 3 into the second absorption tower 2. When the liquid level in the second absorption tower 2 continues to rise and exceeds the set value of the second liquid level detection device 29, the interlocking control valve 291 opens, sending the sodium sulfide solution from the bottom of the second absorption tower 2 into the sulfidation reactor. In the first absorption tower 1, due to the continuous replenishment of acidic wastewater, the first liquid level detection device 12 interlocks with the first output control valve 121, sending the acidic wastewater that has absorbed hydrogen sulfide gas into the sulfidation reactor.

[0071] During this period, the absorbent in the first to third absorption towers 3 is automatically replaced, which enhances the hydrogen sulfide absorption efficiency. The value of the hydrogen sulfide online analysis device decreases, the interlocked conveying control valve is closed, and the absorbent in the system automatically closes the drain valve one after another, so that all the absorbent is circulated for absorption.

[0072] The hydrogen sulfide exhaust fan 4 is located between the second absorption tower 2 and the third absorption tower 3. Before the inlet of fan 4 is a high-concentration hydrogen sulfide exhaust gas pipeline. Even if a leak occurs in the pipeline, the negative pressure will prevent the toxic and harmful hydrogen sulfide exhaust gas from leaking into the ambient air and causing pollution. Furthermore, since the hydrogen sulfide has already undergone two stages of absorption, the concentration at the outlet of fan 4 is low; therefore, even if a leak occurs, the environmental impact will be limited.

[0073] In the description of this application, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. Furthermore, the terms "first," "second," and "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0074] Unless otherwise explicitly specified and limited, the terms "set up" and "connected" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0075] The above description of the disclosed embodiments enables those skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. An exhaust gas treatment system, characterized in that, It includes a first absorption tower system, a second absorption tower system, and a third absorption tower system; The first absorption tower system includes a first absorption tower, a first spray device, and a first spray liquid output pipe. The first absorption tower is provided with a first liquid inlet, a first tail gas inlet, a first liquid outlet, and a first tail gas outlet. The first spray device is connected to the first liquid outlet through a first pipeline, and a first delivery pump and a first control valve are provided on the first pipeline. The first spray liquid output pipe is connected to the first pipeline, and a first output control valve is provided on the first spray liquid output pipe. The second absorption tower system includes a second absorption tower, a second spray device, and a second spray liquid output pipe. The second absorption tower is provided with a second liquid inlet, a second tail gas inlet, a second liquid outlet, and a second tail gas outlet. The second tail gas inlet is connected to the first tail gas outlet. The second spray device is connected to the second liquid outlet through a second pipeline, and a second delivery pump and a second control valve are provided on the second pipeline. The second spray liquid output pipe is connected to the second pipeline, and a second output control valve is provided on the second spray liquid output pipe. The third absorption tower system includes a third absorption tower, a third spray device, and a third spray liquid output pipe. The third absorption tower is provided with a third liquid inlet, a third tail gas inlet, a third liquid outlet, and a third tail gas outlet. The third tail gas inlet is connected to the second tail gas outlet. The third spray device is connected to the third liquid outlet through a third pipeline, and the third pipeline is provided with a third delivery pump and a third control valve. One end of the third spray liquid output pipe is connected to the third pipeline, and the other end is connected to the second liquid inlet. The third spray liquid output pipe is provided with a third output control valve.

2. The exhaust gas treatment system according to claim 1, characterized in that, The first absorption tower system further includes a first liquid level detection device, which is disposed on the first absorption tower and is signal-connected to the first output control valve; and / or, the first output control valve is an automatic control valve; and / or The first liquid inlet and the first exhaust gas inlet are located on the side wall of the first absorption tower, and the first liquid inlet is located above the first exhaust gas inlet; And / or, the first exhaust gas outlet is located at the top of the first absorption tower, and the first spray device is located at the upper part of the first absorption tower.

3. The exhaust gas treatment system according to claim 1, characterized in that, The second absorption tower system further includes a second liquid level detection device, which is installed on the second absorption tower and is signal-connected to the second output control valve; and / or, the second output control valve is an automatic control valve; and / or, The second absorption tower is a packed tower; the second absorption tower includes a spray section, a packing section and a hollow section from top to bottom, and the second tail gas inlet, the second liquid outlet and the second liquid outlet are all located in the hollow section; the second spray device is located in the spray section; the second tail gas outlet is located at the top of the second absorption tower.

4. The exhaust gas treatment system according to claim 3, characterized in that, The second absorption tower system also includes a second absorption tower demister, which is disposed above the second spray device and below the second exhaust gas outlet.

5. The exhaust gas treatment system according to claim 1, characterized in that, The third absorption tower system further includes a third liquid level detection device, which is installed on the third absorption tower and is signal-connected to its corresponding third output control valve; and / or, the third output control valve is an automatic control valve; and / or The third exhaust gas inlet is connected to the second exhaust gas outlet via a gas pipeline, and a fan is installed on the gas pipeline; a drain pipe is also connected to the third pipeline, and a drain valve is installed on the drain pipe; and / or, The third absorption tower is a packed tower; the third absorption tower includes a spray section, a packing section and a hollow section from top to bottom; the third tail gas inlet, the third liquid outlet and the third liquid inlet are all located in the hollow section; the third spray device is located in the spray section; the third tail gas outlet is located at the top of the third absorption tower.

6. The exhaust gas treatment system according to claim 5, characterized in that, The third absorption tower system further includes a third absorption tower water absorber and a third absorption tower demister, wherein the third absorption tower water absorber is disposed above the third spray device; the second absorption tower demister is disposed above the third absorption tower water absorber and below the third exhaust gas outlet; and / or, the third absorption tower system further includes a third absorption tower pH meter disposed at the lower part of the third absorption tower.

7. The exhaust gas treatment system according to any one of claims 1-6, characterized in that, It also includes an absorbent storage tank, which is connected to the third liquid inlet via a delivery pipe, and the delivery pipe is equipped with a delivery control valve.

8. The exhaust gas treatment system according to claim 7, characterized in that, It also includes an online exhaust gas analyzer, the input of which is connected to the third exhaust gas outlet, and the output of which is connected to the delivery control valve signal.

9. The exhaust gas treatment system according to claim 8, characterized in that, The third absorption tower system also includes a tail gas chimney, which is located above the third tail gas outlet and its bottom end is connected to the third tail gas outlet; the input end of the tail gas online analysis device is located inside the tail gas chimney.

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