Tail gas treatment system and application thereof

Abstract

The invention belongs to the technical field of tail gas treatment, and particularly relates to a tail gas treatment system and application thereof. The tail gas treatment system provided by the invention is internally provided with a three-stage absorption tower system, so that the absorption efficiency of hydrogen sulfide is far higher than that of traditional single-stage alkali liquor absorption, and up-to-standard emission of hydrogen sulfide tail gas after absorption can be ensured. The three stages of absorption towers are connected in series to absorb hydrogen sulfide, sulfur elements in byproduct hydrogen sulfide in the vulcanization reaction process are effectively utilized to the maximum extent, the enriched sulfur elements are brought into the vulcanization reactor to react with heavy metals in waste acid wastewater to the maximum extent, and the vulcanization efficiency in the vulcanization reaction process is greatly improved; meanwhile, the dosage of alkali liquor for absorbing hydrogen sulfide is greatly reduced. The tail gas absorption efficiency is improved, up-to-standard discharge of waste is guaranteed, the vulcanization reaction efficiency is improved, and the sulfur element in the vulcanizing agent is enabled to react with heavy metal to the maximum extent.

Description

Technical Field

[0001] The invention belongs to the technical field of tail gas treatment, and in particular relates to a tail gas treatment system and application thereof. Background Art

[0002] The use of sulfidation technology to treat heavy metal-containing acid wastewater has a very high efficiency in production practice. The extremely low solubility product constant of heavy metal sulfides ensures that the heavy metal ions in the acid can be precipitated in the form of sulfide under acidic conditions, thereby removing the heavy metals in the acid wastewater. However, in an acidic environment, the sulfur ions and hydrogen ions of sodium sulfide combine to produce a byproduct of hydrogen sulfide gas. The reaction equation is as follows:

[0003] H2SO4+Na2S=H2S↑+Na2SO4

[0004] Hydrogen sulfide is a highly toxic and flammable hazardous substance. Its emission limit is strictly required in the "Emission Standard of Malodorous Pollutants" (GB14554-93). The absorption efficiency of hydrogen sulfide tail gas restricts whether the exhaust gas can meet the emission standards during the sulfidation technology treatment of heavy metal-containing acid wastewater.

[0005] The traditional hydrogen sulfide absorption process uses sodium hydroxide to spray and absorb in the absorption tower, which has low mass transfer efficiency and poor reaction effect. Especially when the absorption liquid is saturated and needs to be replaced with alkaline solution, new sodium hydroxide solution is not added in time, and hydrogen sulfide gas often exceeds the standard. Summary of the invention

[0006] In view of the problems existing in the prior art, the present invention provides an exhaust gas treatment system and its application, and the present invention specifically includes the following contents:

[0007] A tail gas treatment system comprises 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 the first pipeline is provided with a first delivery pump and a first control valve; the first spray liquid output pipe is connected to the first pipeline, and the first spray liquid output pipe is provided with a first output control valve;

[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 the second pipeline is provided with a second delivery pump and a second control valve; the second spray liquid output pipe is connected to the second pipeline, and the second spray liquid output pipe is provided with a second output control valve;

[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 delivery pipe is connected to the third pipeline, and the other end is connected to the second liquid inlet, and the third spray liquid delivery pipe is provided with a third output control valve.

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

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

[0013] Furthermore, the second absorption tower system further comprises a second liquid level detection device, which is disposed on the second absorption tower and is connected to the second output control valve signal; 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 comprises a spray section, a packing section and a hollow section from top to bottom, the second tail gas inlet, the second liquid outlet and the second liquid inlet are all arranged in the hollow section; the second spray device is arranged in the spray section; the second tail gas outlet is arranged at the top of the second absorption tower.

[0015] Further, the second absorption tower system also includes a second absorption tower foam catcher, which is arranged above the second spray device and below the second tail gas outlet. Preferably, the second absorption tower foam catcher is a foam catcher wire mesh laid above the second spray device and covering the cross section of the second absorption tower.

[0016] Furthermore, the third absorption tower system further comprises a third liquid level detection device, which is arranged on the third absorption tower and is connected to a third output control valve signal; and / or, the third output control valve is an automatic control valve; and / or,

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

[0018] The third absorption tower is a packed tower; the third absorption tower comprises a spray section, a packed 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 arranged in the hollow section; the third spray device is arranged in the spray section; the third tail gas outlet is arranged at the top of the third absorption tower; and / or,

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

[0020] Further, the third absorption tower system further comprises a third absorption tower water absorber and a third absorption tower foam catcher, wherein the third absorption tower water absorber is arranged above the third spray device; the second absorption tower foam catcher is arranged above the third absorption tower water absorber and below the third tail gas outlet. Preferably, the third absorption tower foam catcher is a foam catcher mesh laid above the third spray device and covering the cross section of the third absorption tower.

[0021] Furthermore, it also includes an absorption liquid storage tank, which is connected to the third liquid inlet through a delivery pipeline, and a delivery control valve is provided on the delivery pipeline.

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

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

[0024] A method for treating tail gas containing hydrogen sulfide by using the tail gas treatment system, utilizing the three-stage absorption tower in the system of the present invention to absorb the tail gas containing hydrogen sulfide.

[0025] In the primary absorption tower (i.e., the first absorption tower), the heavy metal-containing acid wastewater is used as the spray liquid to reversely absorb the hydrogen sulfide tail gas. The hydrogen sulfide gas reacts with the heavy metals in the acid wastewater, which not only consumes a large amount of hydrogen sulfide in the tail gas, but also pre-treats the acid wastewater to initially reduce the heavy metal concentration in the acid. 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 in the tertiary absorption tower (i.e., the third absorption tower) is connected to the second absorption tower as the absorption liquid, and the hydrogen sulfide tail gas is sprayed and absorbed in the second absorption tower. The main reaction is:

[0032] Na2S+H2S=2NaHS

[0033] The sodium hydrosulfide solution absorbed in the secondary absorption tower can be used as a sulfiding agent in the sulfidation reaction process of heavy metal-containing acid wastewater and can be reused 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 concentration of hydrogen sulfide in the tail gas has been greatly reduced, and then the tail gas is transported to the third absorption tower through a fan. The third absorption tower is a packed tower with at least one (preferably two) packing layers built in. The prepared sodium hydroxide solution (preferably 10% by mass concentration) is used for spraying and absorption. The gas and liquid are in reverse contact, and the low-concentration hydrogen sulfide gas is further absorbed, and finally the emission meets the standards. The three-stage absorption tower is a tower-chimney integrated structure, with liquid distribution pipes evenly distributed on the top of the tower, and a layer of foam-catching wire mesh is set on the top of the pipe to capture the droplets in the tail gas after absorption and discharge them 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 by the reaction is sent to the secondary absorption tower as the secondary circulating absorption liquid.

[0038] Beneficial effects of the present invention:

[0039] The tail gas treatment system provided by the present invention is equipped with a three-stage absorption tower system, and the absorption efficiency of hydrogen sulfide is much higher than that of the traditional single-stage alkaline solution absorption, which can ensure that the hydrogen sulfide tail gas meets the emission standards after absorption. At the same time, the first-stage hydrogen sulfide absorption is used as a pretreatment of the polluted acid wastewater, and the by-product hydrogen sulfide gas is used to preliminarily reduce the heavy metal concentration before the formal sulfidation reaction of the polluted acid wastewater, which not only absorbs the tail gas, but also reduces the production load of the sulfidation reaction section; the second-stage hydrogen sulfide absorption tower uses the sodium sulfide solution produced by the third-stage absorption to be connected to the absorption tower as the absorption liquid, and after the absorption is complete, the generated 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 absorption liquid, which serves as the safety absorption of the whole system to ensure that the tail gas meets the emission standards. The three-stage absorption tower is connected in series with the device for absorbing hydrogen sulfide, which can effectively utilize the sulfur element in the by-product hydrogen sulfide in the sulfidation reaction to the maximum extent, and bring the enriched sulfur element into the sulfidation reactor to react with the heavy metals in the acid wastewater to the maximum extent, which greatly improves the sulfidation efficiency of the sulfidation reaction process and greatly reduces the amount of alkali solution used to absorb hydrogen sulfide. It not only improves the tail gas absorption efficiency and ensures that the waste meets the discharge standards, but also improves the sulfidation reaction efficiency and ensures that the sulfur element in the sulfiding agent reacts with the heavy metals to the maximum extent.

[0040] At the same time, the fan (environmental protection fan) is installed between the second-stage absorption tower and the third-stage absorption tower to ensure that the first-stage and second-stage absorption systems with relatively high hydrogen sulfide concentrations are in a negative pressure state. Even if leaks occur in the pipeline due to aging of the equipment, hydrogen sulfide will not leak into the environment and pollute the air under negative pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 It is a schematic diagram of the structure of the exhaust gas treatment system disclosed in the present invention. DETAILED DESCRIPTION

[0042] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. The embodiments shown below do not limit the invention content described in the claims. In addition, the entire contents of the structures represented by the following embodiments are not limited to those necessary as solutions to the invention described in the claims.

[0043] Reference Figure 1 , a tail gas treatment system, including 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, and 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 through 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, and 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 is connected to the first tail gas outlet 16 through a pipe The second spray device 25 is connected to the second liquid outlet through a second pipeline, and a second delivery pump 21 and a second control valve are provided on the second pipeline; the second spray liquid output pipe 28 is connected to the second pipeline, and a second output control valve 291 is provided 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, and the third absorption tower 3 is provided 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 through a third pipeline, and a third delivery pump 31 and a third control valve are provided on the third pipeline; one end of the third spray liquid delivery pipe 39 is connected to the third pipeline, and the other end is connected to the second liquid inlet 23, and the third spray liquid delivery pipe 39 is provided with a third output control valve 391.

[0044] In some embodiments of the present invention, the first absorption tower system also includes a first liquid level detection device 12, which is arranged on the first absorption tower 1, and the first liquid level detection device 12 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 exhaust gas inlet 13 are arranged on the side wall of the first absorption tower 1, and the first liquid inlet 14 is located above the first exhaust gas inlet 13; preferably, the first exhaust gas outlet 16 is arranged at the top of the first absorption tower 1, and the first spray device 15 is arranged at the upper part of the first absorption tower 1.

[0045] In some embodiments of the present invention, the second absorption tower system also includes a second liquid level detection device 29, which is arranged on the second absorption tower 2, and the second liquid level detection device 29 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 arranged in the hollow section; the second spray device 25 is arranged in the spray section; the second tail gas outlet is arranged at the top of the second absorption tower 2.

[0046] In some embodiments of the present invention, the second absorption tower system further comprises a second absorption tower scummer 26, which is arranged above the second spray device 25 and below the second tail gas outlet. Preferably, the second absorption tower scummer 26 is a scummer wire mesh laid above the second spray device 25 and covering the cross section of the second absorption tower 2.

[0047] In some embodiments of the present invention, the third absorption tower system also includes a third liquid level detection device 392, which is arranged on the third absorption tower 3, and the third liquid level detection device 392 is signal-connected to the third output control valve 391; preferably, the third output control valve 391 is an automatic control valve; preferably, the third exhaust gas inlet 32 ​​is connected to the second exhaust gas outlet through a gas pipeline, and a fan 4 is arranged on the gas pipeline; the third pipeline is also connected to a shower pipe 41, and a shower valve is arranged on the shower 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 exhaust gas inlet 32, the third liquid outlet, and the third liquid inlet 33 are all arranged in the hollow section; the third spray device 34 is arranged in the spray section; the third exhaust gas outlet is arranged at the top of the third absorption tower 3.

[0048] In some embodiments of the present invention, the third absorption tower system further comprises a third absorption tower pH meter 38 disposed at the lower portion of the third absorption tower 3 , and the third absorption tower pH meter 38 is ensured to be immersed in the absorption liquid at the bottom of the third absorption tower 3 .

[0049] In some embodiments of the present invention, the third absorption tower system further comprises a third absorption tower water absorber 361 and a third absorption tower foam catcher 36, wherein the third absorption tower water absorber 361 is arranged above the third spray device 34; the second absorption tower foam catcher 26 is arranged above the third absorption tower water absorber 361 and below the third tail gas outlet. Preferably, the third absorption tower foam catcher 36 is a foam catcher mesh laid above the third spray device 34 and covering the cross section of the third absorption tower 3.

[0050] In some embodiments of the present invention, an absorption liquid storage tank 5 is further included, and the absorption liquid storage tank 5 is connected to the third liquid inlet 33 through a delivery pipeline, and the delivery pipeline is provided with a delivery control valve 51. Preferably, the absorption liquid storage tank 5 is a high-level tank, and the absorption liquid can be delivered to the third absorption tower 3 by gravity.

[0051] In some embodiments of the present invention, an online exhaust gas analyzer 371 is further 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 the present invention, the third absorption tower system also includes a tail gas chimney 37, which is arranged above the third tail gas outlet and connected to the third tail gas outlet at the bottom; the input end of the tail gas online analysis device 371 is arranged in the tail gas chimney 37.

[0053] A method for treating tail gas containing hydrogen sulfide using the tail gas treatment system, using the three-stage absorption tower in the system of the present invention to absorb the tail gas containing hydrogen sulfide, wherein:

[0054] In the primary absorption tower (i.e., the first absorption tower 1), the heavy metal-containing acid wastewater is used as the spray liquid to reversely absorb the hydrogen sulfide tail gas. The hydrogen sulfide gas reacts with the heavy metals in the acid wastewater, which not only consumes a large amount of hydrogen sulfide in the tail gas, but also pre-treats the acid wastewater to preliminarily reduce the heavy metal concentration in the acid. The reaction equation is as follows:

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

[0056] 2AsO43+ +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 in the tertiary absorption tower (i.e., the third absorption tower 3) is connected to the second absorption tower 2 as the absorption liquid, and the hydrogen sulfide tail gas is sprayed and absorbed in the second absorption tower 2. The main reaction is:

[0061] Na2S+H2S=2NaHS

[0062] The sodium hydrosulfide solution absorbed in the secondary absorption tower can be used as a sulfiding agent in the sulfidation reaction process of heavy metal-containing acid wastewater and can be reused 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 tail gas has been greatly reduced, and the tail 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 layers built in. The prepared sodium hydroxide solution (preferably 10% by mass concentration) is used for spraying and absorption. The gas and liquid are in reverse contact, and the low-concentration hydrogen sulfide gas is further absorbed, and finally reaches the standard for discharge. The three-stage absorption tower is a tower-chimney integrated structure, with liquid distribution pipes evenly distributed on the top of the tower, and a layer of foam-catching wire mesh is set on the top of the pipe to capture the droplets in the tail gas after absorption and discharge them 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 by the reaction is sent to the secondary absorption tower as the secondary circulating absorption liquid.

[0067] The tail gas treatment system disclosed in the present invention, when actually used to treat tail gas containing hydrogen sulfide, the hydrogen sulfide gas generated by the sulfidation unit reaction is collected in the waste gas main pipeline through the waste gas collection device, and the waste gas main pipeline is connected to the first tail gas inlet 13 of the first absorption tower 1, and the first tail gas inlet 13 is arranged above the circulating liquid level in the first absorption tower 1. The hydrogen sulfide waste gas is sprayed and absorbed in the first absorption tower 1 with the dirty acid from the acid water homogenization tank in reverse, and the first liquid inlet 14 is arranged above the first tail gas inlet 13. The lower part of the first absorption tower 1 is connected to the first delivery pump 11. During normal production, the dirty acid at the outlet of the first delivery pump 11 is transported to the upper part of the first absorption tower 1 as the circulating absorption liquid, and the hydrogen sulfide waste gas is sprayed and absorbed by the first spray device 15, and the other part is transported to the sulfidation reaction unit through the first spray liquid output pipe 18 for sulfidation reaction.

[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 arranged between the upper 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 contacted and absorbed by the absorption liquid sprayed from top to bottom in reverse direction, and the absorption liquid is sent to the second spray device 25 at the top of the tower for spraying and absorption through the second delivery pump 21. The sodium hydrosulfide solution generated by the absorption of the second absorption tower 2 is sent to the sulfidation reaction unit through the second spray liquid output pipe 28 for sulfidation reaction. After absorption, the waste gas is successively sent to the exhaust fan 4 through the gas pipeline after the acid foam is captured by the second absorption tower condenser 26. In order to prevent the water mist of the hydrogen sulfide waste gas at the outlet of the second absorption tower 2 from being insufficiently captured and entering the exhaust fan 4, the front spraying and drainage of the fan 4 is opened once per shift during production.

[0069] The hydrogen sulfide waste gas after two-stage absorption is pressurized by the tail gas blower 4 and sent to the third absorption tower 3. The third absorption tower 3 is a packed tower. The third tail gas inlet 32 ​​of the third absorption tower 3 is set between the absorption liquid level and the packing of the third absorption tower 3, and absorbs the absorption liquid sprayed from top to bottom in the reverse direction. The absorption liquid is sent to the third spraying device 34 at the top of the tower for cyclic absorption through the third delivery pump 31. After the tail gas absorbed in the tower passes through the water collector of the third absorption tower 3 at the top of the tower and the third absorption tower scum 36 to capture water mist, it is discharged through the tail gas chimney 37 in compliance with the standards.

[0070] When the absorption liquid is close to saturation, the absorption efficiency decreases, and the concentration of the hydrogen sulfide online analyzer reaches the set value, the transmission control valve is interlocked to open, and the liquid level of the third absorption tower 3 continues to rise. When the liquid level is higher than the set value of the third liquid level detection device 392, the third output control valve 391 is interlocked to open, and the absorption liquid with low alkali content at the bottom of the third absorption tower 3 is sent to the second absorption tower 2. When the liquid level of the second absorption tower 2 continues to rise and the liquid level value exceeds the set value of the second liquid level detection device 29, the second output control valve 291 is interlocked to open, and the sodium sulfide solution at the bottom of the second absorption tower 2 is sent to 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 the first output control valve 121 to operate, and the acidic wastewater that has absorbed hydrogen sulfide gas is transported to the sulfidation reactor.

[0071] During this period, the absorption liquid in the first to third absorption towers 3 is automatically replaced to enhance the hydrogen sulfide absorption efficiency again, the value of the hydrogen sulfide online analysis device decreases, the interlocking delivery control valve is closed, the absorption liquid in the system automatically closes the drain valve one after another, and the absorption liquid is fully circulated and absorbed.

[0072] The hydrogen sulfide tail gas fan 4 is arranged between the second absorption tower 2 and the third absorption tower 3. In front of the inlet of the fan 4 is a tail gas delivery pipeline with a high hydrogen sulfide concentration. Even if there is a leak in the pipeline, due to the negative pressure of the pipeline, the toxic and harmful hydrogen sulfide waste gas will not leak into the ambient air to cause pollution. At the outlet of the fan 4, since the hydrogen sulfide has been absorbed in two stages, the concentration is relatively low. Even if leakage occurs, the impact on the environment is limited.

[0073] In the description of the present application, it should be noted that the terms "upper", "lower", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present application. In addition, the terms "first", "second", "third", etc., are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0074] Unless otherwise clearly specified and limited, the terms "disposed" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal connection of two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0075] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one 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 will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A tail 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 the first pipeline is provided with a first delivery pump and a first control valve; the first spray liquid output pipe is connected to the first pipeline, and the first spray liquid output pipe is provided with a first output control valve; 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 the second pipeline is provided with a second delivery pump and a second control valve; the second spray liquid output pipe is connected to the second pipeline, and the second spray liquid output pipe is provided with a second output control valve; 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 delivery pipe is connected to the third pipeline, and the other end is connected to the second liquid inlet, and the third spray liquid delivery 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 comprises a first liquid level detection device, which is disposed on the first absorption tower and is connected to the first output control valve signal; and / or, the first output control valve is an automatic control valve; and / or, The first liquid inlet and the first tail gas inlet are arranged on the side wall of the first absorption tower, and the first liquid inlet is located above the first tail gas inlet; And / or, the first tail gas outlet is arranged at the top of the first absorption tower, and the first spraying device is arranged 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 comprises a second liquid level detection device, which is arranged on the second absorption tower and is connected to the second output control valve signal; 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 comprises a spray section, a packing section and a hollow section from top to bottom, the second tail gas inlet, the second liquid outlet and the second liquid inlet are all arranged in the hollow section; the second spray device is arranged in the spray section; the second tail gas outlet is arranged 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 foam collector, which is arranged above the second spray device and below the second tail gas outlet.

5. The exhaust gas treatment system according to claim 1, characterized in that: The third absorption tower system further comprises a third liquid level detection device, which is arranged on the third absorption tower and is connected to a third output control valve signal; and / or, the third output control valve is an automatic control valve; and / or, The third tail gas inlet is connected to the second tail gas outlet via a gas pipeline, and a fan is provided on the gas pipeline; the third pipeline is also connected to a shower pipe, and a shower valve is provided on the shower pipe; and / or, The third absorption tower is a packed tower; the third absorption tower comprises 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 arranged in the hollow section; the third spray device is arranged in the spray section; the third tail gas outlet is arranged 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 also includes a third absorption tower water absorber and a third absorption tower foam collector, wherein the third absorption tower water absorber is arranged above the third spray device; the second absorption tower foam collector is arranged above the third absorption tower water absorber and below the third tail gas outlet; and / or the third absorption tower system also includes a third absorption tower pH meter arranged at the lower part of the third absorption tower.

7. The tail gas treatment system according to any one of claims 1 to 6, characterized in that: It also includes an absorption liquid storage tank, which is connected to the third liquid inlet through a delivery pipeline, and a delivery control valve is provided on the delivery pipeline.

8. The exhaust gas treatment system according to claim 7, characterized in that: It also includes an exhaust gas online analysis device, the input end of the exhaust gas online analysis device is communicated with the third exhaust gas outlet, and the output end of the exhaust gas online analysis device 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 arranged above the third tail gas outlet and connected to the third tail gas outlet at its bottom; the input end of the tail gas online analysis device is arranged in the tail gas chimney.

10. A method for treating tail gas containing hydrogen sulfide using the tail gas treatment system according to any one of claims 1 to 9, characterized in that: In the first absorption tower, acidic heavy metal wastewater is used to spray the tail gas; in the third absorption tower, alkaline solution is used to spray the tail gas.

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