Multistage recovery device for hydrogen sulfide in sulfidation dearsenification tail gas and process thereof

Abstract

The application discloses a kind of multistage recovery device of hydrogen sulfide in sulfuration dearsenification tail gas and process thereof, it is related to tail gas processing technical field, the four processes of desorption pretreatment of excess hydrogen sulfide gas, dirty acid stock solution exposure recovery, dirty acid spray recovery and sodium hydroxide solution spray recovery are included in the application;Among them, desorption tower desorbs hydrogen sulfide in sulfuration liquid, and pretreatment tank is contacted with arsenic-containing dirty acid and desorption tail gas and excess tail gas of sulfuration reaction, to realize first efficient recovery;Tail gas aeration stock solution tank completes secondary recovery while stirring dirty acid;Dirty acid stock solution spray process realizes third recovery;Sodium hydroxide solution is recycled by three-stage spraying to generate sodium sulfide solution, to achieve final recovery.The process through four recovery processes not only reduces the concentration of arsenic and heavy metals in arsenic-containing dirty acid, but also improves the utilization rate of hydrogen sulfide by more than 10%, reduces the consumption of sodium hydroxide by more than 70%, ensures that the tail gas meets the emission standard, and significantly reduces the production cost.

Description

Technical Field

[0001] This invention relates to the field of exhaust gas treatment technology, specifically to a multi-stage recovery device and process for hydrogen sulfide in arsenic removal exhaust gas. Background Technology

[0002] Arsenic-containing waste acid generated during the purification of copper smelting flue gas is typically treated using a "sulfidation arsenic removal" process: hydrogen sulfide is added to react with heavy metal ions to generate sulfide slag. To ensure that the arsenic content meets standards, the amount of hydrogen sulfide added is often excessive, resulting in a high concentration of hydrogen sulfide in the exhaust gas.

[0003] Currently, the common practice for treating related exhaust gases is to use an acid-alkali spray. Although this process is simple to operate, it consumes a large amount of sodium hydroxide, and emissions are prone to exceed standards, especially when treating high-concentration exhaust gases. Furthermore, the cost of auxiliary materials accounts for a relatively high proportion of the total cost of waste acid treatment.

[0004] Therefore, providing a multi-stage recovery device for hydrogen sulfide in arsenic removal tail gas with low sodium hydroxide consumption and thorough tail gas treatment is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] This invention proposes a multi-stage recovery device and process for hydrogen sulfide in arsenic removal tail gas from sulfidation processes. The invention involves four main processes: desorption pretreatment of excess hydrogen sulfide gas, aeration recovery of waste acid stock solution, waste acid spray recovery, and sodium hydroxide solution spray recovery. Specifically, the desorption tower desorbs hydrogen sulfide from the sulfidation liquid; the pretreatment tank achieves initial high-efficiency recovery through contact reaction between arsenic-containing waste acid and the desorbed tail gas and excess tail gas from the sulfidation reaction; the tail gas aeration stock solution tank achieves secondary recovery while stirring the waste acid; the waste acid stock solution spray process achieves tertiary recovery; and the sodium hydroxide solution is sprayed three times to generate sodium sulfide solution, which is then recycled, achieving final recovery. This process, through four recovery stages, not only reduces the concentration of arsenic and heavy metals in the arsenic-containing waste acid but also increases the utilization rate of hydrogen sulfide by more than 10% and reduces sodium hydroxide consumption by more than 70%, ensuring that the tail gas meets emission standards while significantly reducing production costs.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A multi-stage recovery device for hydrogen sulfide in arsenic removal tail gas from sulfidation processes is disclosed. The multi-stage recovery device includes a raw acid tank connected to a first purging tower. The bottom of the first purging tower is connected to a raw acid spray tank. The raw acid spray tank is connected to a sulfidation reactor. The sulfidation reactor is connected to a desorption tower. The desorption tower is connected to a post-sulfidation liquid treatment device. The sulfidation reactor and the desorption tower are respectively connected to a pretreatment reactor, which is connected to both the raw acid tank and the raw acid spray tank. The first hazard removal tower is connected to the first induced draft fan, which is also connected to the hydrogen sulfide synthesis system and the waste acid stock tank. The first pest control tower is connected in sequence to the second and third pest control towers, and the second and third pest control towers are respectively connected to the alkaline spray tank.

[0008] This invention achieves four-stage recovery and utilization of hydrogen sulfide in exhaust gas. Building upon existing alkaline washing, it incorporates three pre-treatment "acid washing" processes: First, the exhaust gas, initially high in hydrogen sulfide, reacts with waste acid in a pretreatment tank, achieving primary recovery of hydrogen sulfide. Then, the pretreated exhaust gas is aerated at the bottom of a waste acid stock tank, serving both a stirring function and allowing the hydrogen sulfide in the exhaust gas to react with the waste acid in the tank, achieving secondary recovery of hydrogen sulfide. Finally, the aerated exhaust gas is introduced into the first treatment tower, where waste acid spraying achieves a third stage of hydrogen sulfide recovery. After the three acid washes, the hydrogen sulfide content in the exhaust gas is extremely low. At this point, a three-stage alkaline washing process is implemented, involving sodium hydroxide solution spraying and circulating absorption in the second, third, and intermediate treatment towers to ensure the exhaust gas meets emission standards. The resulting sodium sulfide is then slowly introduced into a sulfidation reactor, achieving four-stage recovery and utilization of hydrogen sulfide in the exhaust gas.

[0009] Preferably, the bottom of the waste acid stock solution tank is connected to the spray assembly of the first pest control tower via a booster pump.

[0010] Preferably, the first toxic gas removal tower is connected to the tail gas pipeline of the hydrogen sulfide synthesis system via a first induced draft fan, and the top of the waste acid raw material tank is connected to the first induced draft fan. The hydrogen sulfide synthesis system is connected to the sulfide reactor.

[0011] Preferably, the pretreatment reactor is connected to the aeration device of the waste acid stock solution tank via a second induced draft fan.

[0012] Preferably, the aeration device includes an aeration pipe and an aeration element, wherein the aeration element is a mesoporous or microporous aeration element, and is provided with micropores of elastic material.

[0013] When the second induced draft fan supplies air, the slits of the aeration element open, and the gas rises from bottom to top, allowing the hydrogen sulfide in the exhaust gas discharged by the induced draft fan to fully contact and react with the waste acid in the waste acid raw material tank. This achieves the effect of recovering and utilizing the hydrogen sulfide in the exhaust gas, and also plays a stirring role. When the machine stops, the induced draft fan stops supplying air, and the slits automatically close to prevent the bottom of the waste acid raw material tank from accumulating mud and clogging the aeration device.

[0014] Preferably, the waste acid spray tank is connected to the pretreatment reactor via a pretreatment circulation pump, and the waste acid spray tank is connected to the sulfidation reactor via a sulfidation reaction inlet pump.

[0015] Preferably, an intermediate pest control tower is provided between the second pest control tower and the third pest control tower, the intermediate pest control tower being connected to the top of the second pest control tower and to the bottom of the third pest control tower. The spray assembly of the second pest control tower is connected to the alkaline spray tank via a first alkaline circulating pump, the spray assembly of the third pest control tower is connected to the alkaline spray tank via a second alkaline circulating pump, and the spray assembly of the intermediate pest control tower is connected to the alkaline spray tank via a reverse spray pump. The bottom of the second and third pest control towers are connected to the alkaline spray tank.

[0016] Preferably, the sulfidation reactor and the desorption tower are connected by a post-sulfidation liquid discharge pump, the bottom of the desorption tower is connected to the inlet pipe of the post-sulfidation liquid treatment device, and the exhaust port of the post-sulfidation liquid treatment device is connected to the desorption tower.

[0017] Preferably, a bypass pipe is provided on the main pipeline connecting the outlet of the first alkali circulation pump to the second purging tower. The bypass pipe is connected to the top of the sulfidation reactor, and a regenerated alkali inlet regulating valve is installed on the bypass pipe. The valve controls the discharge of the regenerated alkali into the sulfidation reactor to react with the waste acid.

[0018] A multi-stage recovery process for hydrogen sulfide in arsenic removal tail gas, employing the aforementioned multi-stage recovery device, specifically includes the following steps: (1) Pretreatment and recovery: The waste acid in the waste acid raw liquid tank is pumped to the first hazard removal tower for spraying the sulfidation and arsenic removal tail gas. The hydrogen sulfide in the tail gas of the hydrogen sulfide synthesis system reacts with the waste acid to obtain liquid that flows into the waste acid spray tank. The sulfidation reaction inlet pump pumps the liquid into the sulfidation reactor to react with the hydrogen sulfide. The excess gas is discharged into the pretreatment reactor. The sulfidated liquid is sent to the desorption tower by the external discharge pump to desorb the hydrogen sulfide in the sulfidated liquid and then discharge it into the pretreatment reactor. The pretreatment circulation pump delivers waste acid to react with the gas in the pretreatment reactor to complete the first recovery. (2) Aeration recovery: The second blower blows the gas obtained from the pretreatment reactor into the bottom of the waste acid raw liquid tank for aeration. The hydrogen sulfide in the gas reacts with the waste acid to complete the secondary recovery. (3) Deep recovery of waste acid by spraying: The first induced draft fan sends the residual gas in the waste acid raw liquid tank into the first removal tower to carry out the waste acid spraying reaction to achieve three-stage recovery; (4) Alkali spray recovery: The gas obtained from the first purification tower is sequentially passed through the second purification tower, the intermediate purification tower, and the third purification tower for three-stage alkali spray to generate sodium sulfide, completing four recovery processes. The flow rate of the regenerated alkali is adjusted according to the pH value of the alkali spray tank (closed when pH > 11.5, adjusted to 0.3-0.4 m³ when pH < 11.5). 3 / h, adjust to 0.4-0.5m when pH < 11.0. 3 / h, adjust to 0.5-0.6m when pH < 10.5. 3 ( / h), the recovered sodium sulfide-containing circulating liquid flows back to the alkaline spray tank by gravity, and then the sodium sulfide-containing circulating liquid is pumped into the sulfidation reactor through the bypass pipe of the first alkaline circulating pump to react with the waste acid to regenerate hydrogen sulfide.

[0019] Compared with the prior art, the present invention has the following beneficial effects: (1) Multi-stage recovery process: This invention upgrades the traditional one-acid-one-alkali process to three-acid-three-alkali washing through a four-stage process of pretreatment reaction, aeration and stirring, waste acid spraying and alkali neutralization, and increases the hydrogen sulfide recovery rate to more than 99%. (2) Innovation of aeration in waste acid stock solution tank: This invention realizes the three-in-one function of reaction-stirring-anti-clogging. By aeration with hydrogen sulfide in the tail gas at the bottom, the hydrogen sulfide in the tail gas reacts with the waste acid stock solution to generate sulfide slag, which reduces the arsenic concentration in waste acid and reduces and utilizes the hydrogen sulfide in the tail gas. While aerating and stirring, the elastic microporous aerator automatically closes when the machine stops to avoid the sulfide slag generated by aeration clogging the aeration device. (3) Sodium sulfide recycling: The flow rate of alkaline solution is dynamically adjusted according to the pH value to convert sodium sulfide into hydrogen sulfide and participate in the reaction again, reducing the consumption of sodium hydroxide by more than 70%. (4) This invention achieves four-fold recovery and utilization of hydrogen sulfide in tail gas by washing it with three acids and three alkalis. The whole process is reasonably designed, continuous, efficient, economical and environmentally friendly. After three acid washes, the content of hydrogen sulfide in tail gas is greatly reduced, the overall consumption of sodium hydroxide is reduced, and the cost of auxiliary materials for tail gas treatment is reduced. It is suitable for treating tail gas generated by processes with high hydrogen sulfide content, such as sulfide removal and arsenic removal. The utilization rate of hydrogen sulfide can be increased by more than 10%, and the consumption of sodium hydroxide can be reduced by more than 70%. At the same time, it can ensure that the tail gas meets the emission standards. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. The drawings in this description are merely embodiments of the present invention.

[0021] Figure 1 This is a schematic diagram of the structure of the device according to an embodiment of the present invention; Figure 2 This is a schematic diagram of the structure of a prior art device that is a comparative example of the present invention. Detailed Implementation

[0022] Embodiments of the present invention are described below, examples of which are shown in the accompanying drawings. The embodiments described with reference to the drawings are exemplary and intended to explain the present invention, but are not to be construed as limiting the present invention.

[0023] like Figure 1 This invention provides a multi-stage recovery device for hydrogen sulfide in arsenic removal tail gas, including components such as a raw acid tank 1, a raw acid booster pump 2, and a raw acid spray tank 3, specifically: The bottom of the raw acid solution tank 1 is connected to the spray assembly of the first hazard removal tower 17 via the raw solution lift pump 2. The bottom of the first hazard removal tower 17 is connected to the raw acid spray tank 3. The raw acid spray tank 3 is connected to the sulfidation reactor 6. The sulfidation reactor 6 is connected to the desorption tower 9. The desorption tower 9 is connected to the sulfidation liquid treatment device 12. The sulfidation reactor 6 and the desorption tower 9 are respectively connected to the pretreatment reactor 7. The pretreatment reactor 7 is respectively connected to the raw acid solution tank 1 and the raw acid spray tank 3. The first pest control tower 17 is connected to the first induced draft fan 11, and the first induced draft fan 11 is also connected to the hydrogen sulfide synthesis system 20 and the waste acid raw liquid tank 1. The first disinfection tower 17 is connected in sequence to the second disinfection tower 18 and the third disinfection tower 19, and the second disinfection tower 18 and the third disinfection tower 19 are respectively connected to the alkaline spray tank 13. Preferably, the first toxic gas removal tower 17 is connected to the exhaust gas pipe of the first induced draft fan 11 and the hydrogen sulfide synthesis system 20, and the top of the waste acid raw liquid tank 1 is connected to the first induced draft fan 11; the hydrogen sulfide synthesis system 20 is connected to the sulfide reactor 6. Preferably, the pretreatment reactor 7 is connected to the aeration device of the waste acid stock solution tank 1 via the second induced draft fan 10; Preferably, the aeration device includes an aeration pipe and an aeration element. The aeration element is a medium-hole or micro-hole aeration element with micro-pores made of elastic material. When the second blower 10 supplies air, the pores of the aeration element open, and the gas flows from bottom to top, allowing the hydrogen sulfide in the exhaust gas discharged by the blower to fully contact and react with the waste acid in the waste acid stock solution tank 1. This achieves the effect of recycling hydrogen sulfide in the exhaust gas and also plays a stirring role. When the machine stops, the blower stops supplying air, and the pores automatically close to prevent the bottom of the waste acid stock solution tank 1 from accumulating mud and clogging the aeration device. Preferably, the waste acid spray tank 3 is connected to the pretreatment reactor 7 via the pretreatment circulation pump 5, and the waste acid spray tank 3 is connected to the sulfidation reactor 6 via the sulfidation reaction inlet pump 4. Preferably, an intermediate pest control tower 21 is provided between the second pest control tower 18 and the third pest control tower 19. The intermediate pest control tower 21 is connected to the top of the second pest control tower 18 and to the bottom of the third pest control tower 19. The spray assembly of the second pest control tower 18 is connected to the alkaline spray tank 13 via the first alkaline circulating pump 14, the spray assembly of the third pest control tower 19 is connected to the alkaline spray tank 13 via the second alkaline circulating pump 15, and the spray assembly of the intermediate pest control tower 21 is connected to the alkaline spray tank 13 via the reverse spray pump 16. The bottom of the second pest control tower 18 and the bottom of the third pest control tower 19 are connected to the alkaline spray tank 13. Preferably, the sulfidation reactor 6 and the desorption tower 9 are connected by a sulfidation liquid discharge pump 8, the bottom of the desorption tower 9 is connected to the inlet pipe of the sulfidation liquid treatment device 12, and the exhaust port of the sulfidation liquid treatment device 12 is connected to the desorption tower 9. Preferably, a bypass pipe is provided on the main pipeline connecting the outlet of the first alkali circulation pump 14 to the second hazard removal tower 18. The bypass pipe is connected to the top of the sulfidation reactor 6 and is equipped with a regenerated alkali inlet regulating valve.

[0024] The specific process is as follows: The bottom of the raw acid tank 1 is connected to the raw acid lift pump 2. The pumped liquid flows to the spray assembly of the first treatment tower 17. The bottom of the first treatment tower 17 is connected to the top of the raw acid spray tank 3. After spraying, the raw acid flows into the raw acid spray tank 3. The bottom of the raw acid spray tank 3 is connected to the sulfidation reaction inlet pump 4 and the pretreatment circulation pump 5. The sulfidation reaction inlet pump 4 transports the liquid in the raw acid spray tank 3 to the sulfidation reactor 6. The hydrogen sulfide synthesis system 20 is connected to the sulfidation reactor 6. The liquid in the sulfidation reactor 6 reacts with the hydrogen sulfide gas from the hydrogen sulfide synthesis system 20. After sulfidation, the liquid is sent to the desorption tower 9 by the discharge pump 8. The residual gas is discharged into the pretreatment reactor 7. The pretreatment circulation pump 5 transports the liquid in the raw acid spray tank 3 to the pretreatment reactor 7, where it reacts with the residual gas in the sulfidation reactor 6 and the desorption gas in the desorption tower 9. The reacted liquid flows back to the raw acid spray tank 3. The reacted gas is blown into the raw acid tank 1 by the second induced draft fan 10. The bottom aeration device uses an elastic microporous structure for the aeration element, which automatically closes to prevent blockage when the machine stops. The bottom of the desorption tower 9 is connected to the inlet pipe of the sulfidation liquid treatment device 12. The desorbed liquid flows to the sulfidation liquid treatment device 12. The first blower 11 introduces the residual tail gas after aeration of the waste acid raw liquid tank 1 and the tail gas in the tail gas pipe of the hydrogen sulfide synthesis system 20 into the first removal tower 17. The solution is sprayed through the second removal tower 18, the intermediate removal tower 21, and the third removal tower 19 in sequence. The first alkali circulation pump 14, the second alkali circulation pump 15, and the reverse spray pump 16 realize the solution circulation. The sprayed liquid flows back to the alkali spray tank 13. The main pipe connecting the outlet of the first alkali circulation pump 14 to the spray component of the second removal tower 18 is equipped with a bypass pipe, which is connected to the top of the sulfidation reactor 6. The bypass pipe is equipped with a regenerated alkali liquid inlet regulating valve. The valve controls the discharge of the regenerated alkali liquid into the sulfidation reactor 6 to react with the waste acid. Example 1 Will as Figure 1The multi-stage hydrogen sulfide recovery unit in the arsenic removal tail gas from sulfidation is used in the normal production process of the arsenic removal process at Yunnan Tin Copper Industry. The arsenic concentration in the waste acid is 8000 mg / L. The specific steps include: (1) The raw liquid booster pump delivers the waste acid at a rate of 30m³. 3 The flow rate is pumped at / h to the first treatment tower to spray off the exhaust gas, and the liquid flows into the waste acid spray tank. The sulfidation reaction inlet pump is pumped at 30m. 3 The waste acid is fed into the sulfidation reactor at a flow rate of / h, where it reacts with 99% pure hydrogen sulfide produced by the hydrogen sulfide synthesis system. When the pressure exceeds 75 kPa, the residual gas is discharged into the pretreatment reactor. The sulfidated liquid is then discharged at a flow rate of 30m³ / h. 3 The solution is pumped at a flow rate of / h into the desorption tower to desorb the hydrogen sulfide contained in the sulfidated liquid before being discharged into the pretreatment reactor; the pretreatment circulation pump operates at a flow rate of 20m... 3 The waste acid is transported at a flow rate of / h to react with the exhaust gas, completing the initial recovery; (2) Aeration and mixing recovery: The second induced draft fan blows the pretreated exhaust gas at a speed of 1000m³ / h. 3 / h Aeration is introduced into the bottom of the waste acid raw liquid tank (the aeration element has a micropore diameter of 0.1-0.3mm and an elastic material closing pressure of 0.05MPa). The hydrogen sulfide in the exhaust gas reacts with the waste acid, and the raw liquid is stirred at the same time, thus completing the secondary recovery. (3) Deep recovery of waste acid by spraying: The first induced draft fan sprays the residual exhaust gas at a speed of 1000m 3 / h is fed into the first treatment tower, where it reacts with the sprayed waste acid to achieve three-stage recovery; (4) Alkali spray recovery: Subsequently, the tail gas passes through a three-stage alkali spray tower, where a 20% sodium hydroxide solution is circulated and sprayed to generate sodium sulfide, completing four recovery processes. The flow rate of the regenerated alkali is adjusted according to the pH value of the alkali spray tank (closed when pH > 11.5, adjusted to 0.3-0.4 m³ / h when pH < 11.5). 3 / h, adjust to 0.4-0.5m when pH < 11.0. 3 / h, adjust to 0.5-0.6m when pH < 10.5. 3 The circulating liquid containing sodium sulfide is pumped into the sulfidation reactor ( / h) to react with the waste acid to regenerate hydrogen sulfide. The produced hydrogen sulfide then reacts with the waste acid to obtain the sulfidated liquid. Relevant data for 10 days are shown in Table 1.

[0025] Table 1. Relevant data for the 10th

[0026] Example 2 Will as Figure 1 The multi-stage hydrogen sulfide recovery unit in the arsenic removal tail gas from sulfidation is used in the normal production process of the arsenic removal process at Yunnan Tin Copper Industry. The arsenic concentration in the waste acid is 7000 mg / L. The specific steps include: (1) The raw liquid booster pump delivers the waste acid at a rate of 30m³. 3 The flow rate is pumped at / h to the first treatment tower to spray off the exhaust gas, and the liquid flows into the waste acid spray tank. The sulfidation reaction inlet pump is pumped at 30m. 3 The waste acid is fed into the sulfidation reactor at a flow rate of / h, where it reacts with 99% pure hydrogen sulfide produced by the hydrogen sulfide synthesis system. When the pressure exceeds 75 kPa, the residual gas is discharged into the pretreatment reactor. The sulfidated liquid is then discharged at a flow rate of 30m³ / h. 3 The solution is pumped at a flow rate of / h into the desorption tower to desorb the hydrogen sulfide contained in the sulfidated liquid before being discharged into the pretreatment reactor; the pretreatment circulation pump operates at a flow rate of 20m... 3 The waste acid is transported at a flow rate of / h to react with the exhaust gas, completing the initial recovery; (2) Aeration and mixing recovery: The second induced draft fan blows the pretreated exhaust gas at a speed of 1000m³ / h. 3 / h Aeration is introduced into the bottom of the waste acid raw liquid tank (the aeration element has a micropore diameter of 0.1-0.3mm and an elastic material closing pressure of 0.05MPa). The hydrogen sulfide in the exhaust gas reacts with the waste acid, and the raw liquid is stirred at the same time, thus completing the secondary recovery. (3) Deep recovery of waste acid by spraying: The first induced draft fan sprays the residual exhaust gas at a speed of 1000m 3 / h is fed into the first treatment tower, where it reacts with the sprayed waste acid to achieve three-stage recovery; (4) Alkali spray recovery: Subsequently, the tail gas passes through a three-stage alkali spray tower, where a 20% sodium hydroxide solution is circulated and sprayed to generate sodium sulfide, completing four recovery processes. The flow rate of the regenerated alkali is adjusted according to the pH value of the alkali spray tank (closed when pH > 11.5, adjusted to 0.3-0.4 m³ / h when pH < 11.5). 3 / h, adjust to 0.4-0.5m when pH < 11.0. 3 / h, adjust to 0.5-0.6m when pH < 10.5. 3 The circulating liquid containing sodium sulfide is pumped into the sulfidation reactor ( / h) to react with the waste acid to regenerate hydrogen sulfide. The produced hydrogen sulfide then reacts with the waste acid to obtain the sulfidated liquid. The relevant data for 10 days are shown in Table 2.

[0027] Table 2 Relevant data for the 10th

[0028] Example 3 Will as Figure 1 The multi-stage hydrogen sulfide recovery unit in the arsenic removal tail gas from sulfidation is used in the normal production process of the arsenic removal process at Yunnan Tin Copper Industry. The arsenic concentration in the waste acid is 6000 mg / L. The specific steps include: (1) The raw liquid booster pump delivers the waste acid at a rate of 30m³. 3 The flow rate is pumped at / h to the first treatment tower to spray off the exhaust gas, and the liquid flows into the waste acid spray tank. The sulfidation reaction inlet pump is pumped at 30m. 3The waste acid is fed into the sulfidation reactor at a flow rate of / h, where it reacts with 99% pure hydrogen sulfide produced by the hydrogen sulfide synthesis system. When the pressure exceeds 75 kPa, the residual gas is discharged into the pretreatment reactor. The sulfidated liquid is then discharged at a flow rate of 30m³ / h. 3 The solution is pumped at a flow rate of / h into the desorption tower to desorb the hydrogen sulfide contained in the sulfidated liquid before being discharged into the pretreatment reactor; the pretreatment circulation pump operates at a flow rate of 20m... 3 The waste acid is transported at a flow rate of / h to react with the exhaust gas, completing the initial recovery; (2) Aeration and mixing recovery: The second induced draft fan blows the pretreated exhaust gas at a speed of 1000m³ / h. 3 / h Aeration is introduced into the bottom of the waste acid raw liquid tank (the aeration element has a micropore diameter of 0.1-0.3mm and an elastic material closing pressure of 0.05MPa). The hydrogen sulfide in the exhaust gas reacts with the waste acid, and the raw liquid is stirred at the same time, thus completing the secondary recovery. (3) Deep recovery of waste acid by spraying: The first induced draft fan sprays the residual exhaust gas at a speed of 1000m 3 / h is fed into the first treatment tower, where it reacts with the sprayed waste acid to achieve three-stage recovery; (4) Alkali spray recovery: Subsequently, the tail gas passes through a three-stage alkali spray tower, where a 20% sodium hydroxide solution is circulated and sprayed to generate sodium sulfide, completing four recovery processes. The flow rate of the regenerated alkali is adjusted according to the pH value of the alkali spray tank (closed when pH > 11.5, adjusted to 0.3-0.4 m³ / h when pH < 11.5). 3 / h, adjust to 0.4-0.5m when pH < 11.0. 3 / h, adjust to 0.5-0.6m when pH < 10.5. 3 The circulating liquid containing sodium sulfide is pumped into the sulfidation reactor ( / h) to react with the waste acid to regenerate hydrogen sulfide. The produced hydrogen sulfide then reacts with the waste acid to obtain the sulfidated liquid. The relevant data for 10 days are shown in Table 3.

[0029] Table 3 Relevant data for the 10th

[0030] Comparative Example 1 like Figure 2 As shown, a two-stage hydrogen sulfide recovery device for arsenic removal tail gas is a tail gas recovery device used in Yunnan Tin Copper Industry before the modification of its arsenic removal process. The arsenic concentration in the waste acid is 8000 mg / L. The device specifically includes the following steps: (1) The raw liquid booster pump 2 pumps the waste acid at a rate of 30m³. 3 The flow rate is pumped at / h to the first treatment tower 17 to spray off the tail gas, and the liquid flows into the waste acid spray tank 3; the sulfidation reaction inlet pump 4 pumps at 30m... 3 The waste acid is fed into the sulfurization reactor 6 at a flow rate of / h, where it reacts with hydrogen sulfide with a purity of 99%. When the pressure exceeds 75KPa, the residual gas is discharged into the tail gas system. (2) Waste acid spraying and recovery: The first induced draft fan 11 sprays the residual exhaust gas at a speed of 1000m³ / h. 3 / h is fed into the first treatment tower 17, where it reacts with the sprayed waste acid to achieve one-time recovery; (3) Alkali spraying and recovery: The tail gas then passes through the alkali spraying tower 13 and the second hazard removal tower 18 for 20% sodium hydroxide solution circulation spraying and recovery. The circulating liquid containing sodium sulfide is discharged to the waste alkali storage tank 22. The relevant data for 10 days are shown in Table 4.

[0031] Table 4. Relevant data for the 10th

[0032] Comparative Example 2 like Figure 2 As shown, a two-stage hydrogen sulfide recovery device for arsenic removal tail gas is a tail gas recovery device used in Yunnan Tin Copper Industry before the modification of its arsenic removal process. The arsenic concentration in the waste acid is 7000 mg / L. The device specifically includes the following steps: (1) The raw liquid booster pump 2 pumps the waste acid at a rate of 30m³. 3 The flow rate is pumped at / h to the first treatment tower 17 to spray off the tail gas, and the liquid flows into the waste acid spray tank 3; the sulfidation reaction inlet pump 4 pumps at 30m... 3 The waste acid is fed into the sulfurization reactor 6 at a flow rate of / h, where it reacts with hydrogen sulfide with a purity of 99%. When the pressure exceeds 75KPa, the residual gas is discharged into the tail gas system. (2) Waste acid spraying and recovery: The first induced draft fan 11 sprays the residual exhaust gas at a speed of 1000m³ / h. 3 / h is fed into the first treatment tower 17, where it reacts with the sprayed waste acid to achieve one-time recovery; (3) Alkali spraying recovery: Subsequently, the tail gas is recycled by circulating 20% ​​sodium hydroxide solution through alkaline spraying tower 13 and second hazard removal tower 18. The circulating liquid containing sodium sulfide is discharged to waste alkali storage tank 22. The relevant data for 10 days are shown in Table 5.

[0033] Table 5. Relevant data for the 10th

[0034] Comparative Example 3 like Figure 2 As shown, a two-stage hydrogen sulfide recovery device for arsenic removal tail gas is a tail gas recovery device used in Yunnan Tin Copper Industry before the modification of its arsenic removal process. The arsenic concentration in the waste acid is 6000 mg / L. The device specifically includes the following steps: (1) The raw liquid booster pump 2 pumps the waste acid at a rate of 30m³. 3 The flow rate is pumped at / h to the first treatment tower 17 to spray off the tail gas, and the liquid flows into the waste acid spray tank 3; the sulfidation reaction inlet pump 4 pumps at 30m... 3The waste acid is fed into the sulfurization reactor 6 at a flow rate of / h, where it reacts with hydrogen sulfide with a purity of 99%. When the pressure exceeds 75KPa, the residual gas is discharged into the tail gas system. (2) Waste acid spraying and recovery: The first induced draft fan 11 sprays the residual exhaust gas at a speed of 1000m³ / h. 3 / h is fed into the first treatment tower 17, where it reacts with the sprayed waste acid to achieve one-time recovery; (3) Alkali spraying and recovery: The tail gas then passes through the alkali spraying tower 13 and the second hazard removal tower 18 for 20% sodium hydroxide solution circulation spraying and recovery. The circulating liquid containing sodium sulfide is discharged to the waste alkali storage tank 22. The relevant data for 10 days are shown in Table 6.

[0035] Table 6. Relevant data for the 10th

[0036] As shown in Table 1-6, the data will be as follows: Figure 2 The two-stage hydrogen sulfide recovery device shown is used in the normal production process of the arsenic removal process of Yunnan Tin Copper Industry. Under different arsenic concentrations in the waste acid, the utilization rate of hydrogen sulfide is 74.05% on average, and the consumption of sodium hydroxide is 3.15t / day on average.

[0037] And will be like Figure 1 The multi-stage hydrogen sulfide recovery device in the arsenic removal tail gas of Yunnan Tin Copper Industry is used in the normal production process of the arsenic removal process of sulfidation. Under different arsenic concentrations in the waste acid, the utilization rate of hydrogen sulfide is 86.14% on average, and the consumption of sodium hydroxide is 0.82t / day on average.

[0038] The comparative results show that the hydrogen sulfide utilization rate of the present invention is 12.07% higher than that of the prior art, the sodium hydroxide consumption is reduced by 2.33 t / day, and the tail gas treatment cost is reduced by 73.97%.

[0039] Furthermore, production data shows that the hydrogen sulfide tail gas recovery efficiency of the technical solution of this invention is more than 10% higher than that of existing technologies (such as CN223010195U), enabling more effective recovery and utilization of hydrogen sulfide resources. The hydrogen sulfide purity of the tail gas treated by this technical solution is reduced by 10% compared with existing technologies, reducing the hydrogen sulfide content in tail gas emissions. The hydrogen sulfide content in the tail gas is stably controlled within 0.28 kg / h, far below the national standard emission limit of 0.33 kg / h. Moreover, when treating the same scale of hydrogen sulfide tail gas, the operating cost of this technical solution is reduced by 70% compared with existing technologies, mainly in terms of sodium hydroxide solution consumption. The sodium hydroxide consumption for treating tail gas is reduced by 70% year-on-year, resulting in significant economic benefits.

[0040] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A multi-stage recovery device for hydrogen sulfide in arsenic removal tail gas, characterized in that, The multi-stage recovery device includes a raw acid tank, which is connected to a first purging tower. The bottom of the first purging tower is connected to a raw acid spray tank, which is connected to a sulfidation reactor. The sulfidation reactor is connected to a desorption tower, and the desorption tower is connected to a post-sulfidation liquid treatment device. The sulfidation reactor and the desorption tower are respectively connected to a pretreatment reactor, which is connected to both the raw acid tank and the raw acid spray tank. The first hazard removal tower is connected to the first induced draft fan, which is also connected to the hydrogen sulfide synthesis system and the waste acid stock tank. The first pest control tower is connected in sequence to the second and third pest control towers, and the second and third pest control towers are respectively connected to the alkaline spray tank.

2. The multi-stage recovery device for hydrogen sulfide in arsenic removal tail gas according to claim 1, characterized in that, The bottom of the waste acid stock solution tank is connected to the spray assembly of the first pest control tower via a booster pump.

3. The multi-stage recovery device for hydrogen sulfide in arsenic removal tail gas according to claim 1, characterized in that, The first hazard removal tower is connected to the tail gas pipeline of the hydrogen sulfide synthesis system via a first induced draft fan, and the top of the waste acid raw liquid tank is connected to the first induced draft fan. The hydrogen sulfide synthesis system is connected to the sulfide reactor.

4. The multi-stage recovery device for hydrogen sulfide in arsenic removal tail gas according to claim 1, characterized in that, The pretreatment reactor is connected to the aeration device of the waste acid stock solution tank via a second induced draft fan.

5. The multi-stage recovery device for hydrogen sulfide in arsenic removal tail gas according to claim 4, characterized in that, The aeration device includes an aeration pipe and an aeration element. The aeration element is a medium-pore or micro-pore aeration element with micropores made of elastic material.

6. The multi-stage recovery device for hydrogen sulfide in arsenic removal tail gas according to claim 1, characterized in that, The waste acid spray tank is connected to the pretreatment reactor via a pretreatment circulation pump, and the waste acid spray tank is connected to the sulfidation reactor via a sulfidation reaction inlet pump.

7. The multi-stage recovery device for hydrogen sulfide in arsenic removal tail gas according to claim 1, characterized in that, An intermediate pest control tower is provided between the second pest control tower and the third pest control tower. The intermediate pest control tower is connected to the top of the second pest control tower and to the bottom of the third pest control tower. The spray assembly of the second pest control tower is connected to the alkaline spray tank via a first alkaline circulating pump, the spray assembly of the third pest control tower is connected to the alkaline spray tank via a second alkaline circulating pump, and the spray assembly of the intermediate pest control tower is connected to the alkaline spray tank via a reverse spray pump. The bottom of the second and third pest control towers are connected to the alkaline spray tank.

8. The multi-stage recovery device for hydrogen sulfide in arsenic removal tail gas according to claim 1, characterized in that, The sulfidation reactor and the desorption tower are connected by a sulfidation liquid discharge pump. The bottom of the desorption tower is connected to the inlet pipe of the sulfidation liquid treatment device, and the exhaust port of the sulfidation liquid treatment device is connected to the desorption tower.

9. The multi-stage recovery device for hydrogen sulfide in arsenic removal tail gas according to claim 7, characterized in that, A bypass pipe is provided on the main pipeline connecting the outlet of the first alkali circulation pump to the second hazard removal tower. The bypass pipe is connected to the top of the sulfidation reactor and is equipped with a regenerated alkali inlet regulating valve. The valve controls the discharge of regenerated alkali into the sulfidation reactor to react with the waste acid.

10. A multi-stage recovery process for hydrogen sulfide in arsenic removal tail gas, characterized in that, The multi-stage recycling device according to any one of claims 1-9 specifically includes the following steps: (1) Pretreatment and recovery: The waste acid in the waste acid raw liquid tank is pumped to the first hazard removal tower for spraying the sulfidation and arsenic removal tail gas. The hydrogen sulfide in the tail gas of the hydrogen sulfide synthesis system reacts with the waste acid to obtain liquid that flows into the waste acid spray tank. The sulfidation reaction inlet pump pumps the liquid into the sulfidation reactor to react with the hydrogen sulfide. The excess gas is discharged into the pretreatment reactor. The sulfidated liquid is sent to the desorption tower by the external discharge pump to desorb the hydrogen sulfide in the sulfidated liquid and then discharge it into the pretreatment reactor. The pretreatment circulation pump delivers waste acid to react with the gas in the pretreatment reactor to complete the first recovery. (2) Aeration recovery: The second blower blows the gas obtained from the pretreatment reactor into the bottom of the waste acid raw liquid tank for aeration. The hydrogen sulfide in the gas reacts with the waste acid to complete the secondary recovery. (3) Deep recovery of waste acid by spraying: The first induced draft fan sends the residual gas in the waste acid raw liquid tank into the first removal tower to carry out the waste acid spraying reaction to achieve three-stage recovery; (4) Alkali spraying recovery: The gas obtained from the first purification tower is sequentially sprayed with alkali in the second purification tower, the intermediate purification tower and the third purification tower to generate sodium sulfide, completing four recovery processes. The recovered sodium sulfide-containing circulating liquid flows back to the alkali spraying tank by gravity, and then the sodium sulfide-containing circulating liquid is pumped into the sulfidation reactor through the bypass pipe of the first alkali circulating pump to react with the waste acid to regenerate hydrogen sulfide.

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