An acidic flare gas treatment system

Abstract

The utility model belongs to a kind of acidic flare gas treatment system;Including overhead flare, with the overhead flare matched long-lasting light unit, and with the overhead flare intercommunication's acidic gas supply unit, acidic gas supply unit includes several acidic gas discharge pipelines, several acidic gas discharge pipelines are connected with liquid-separation tank through release main pipeline, the gas phase outlet of liquid-separation tank is connected with overhead flare, the liquid phase outlet of liquid-separation tank is connected with condensate treatment tank through condensate pump;The condensate treatment tank is at least provided with condensate inlet and sodium hypochlorite solution inlet;The distance between the liquid-separation tank and condensate treatment tank is 1~5 meters;With the advantages of reasonable process design, avoid related equipment corrosion, effectively reduce safety risk, and can improve the efficiency of sulfur recovery.

Description

Technical Field

[0001] The utility model belongs to the technical field of acid gas treatment, and specifically relates to an acid flare gas treatment system. Background Art

[0002] Acid flare gas contains a large amount of H₂S gas, which has high water solubility. Therefore, the condensate separated by the knockout drum contains a certain amount of H₂S. The aforementioned condensate can react with metals such as iron and copper to generate sulfides (such as FeS and CuS), accelerating the corrosion of metal pipelines and equipment. If this part of the condensate is discharged directly without treatment, it will cause a series of environmental pollution problems such as water sulfidation, soil acidification, and atmospheric H₂S diffusion. Currently, in flare gas treatment systems, based on the requirements of the Standard for Fire Prevention Design of Petrochemical Enterprises GB 50160-2008 (2018 Edition), the distance between the elevated flare and the waste liquid recovery system is at least 90m. Further, due to the intermittent and low-flow characteristics of the amount of condensate separated by the knockout drum, during long-distance transportation, the condensate cannot be completely transported to the waste liquid recovery system, and the phenomenon of condensate remaining in the equipment or corresponding pipelines is relatively common. The above process will not only accelerate the corrosion of the equipment or corresponding pipelines, but also cause the defects of resource waste and low economic benefit of enterprises due to the failure to recover part of the H₂S. Contents of the Utility Model

[0003] In order to make up for the above deficiencies, the utility model provides an acid flare gas treatment system to solve the technical problems existing in the prior art.

[0004] The technical solution adopted by the utility model to solve its technical problems is as follows: An acid flare gas treatment system, comprising an elevated flare, a pilot burner unit matching the elevated flare, and an acid gas supply unit communicated with the elevated flare. The acid gas supply unit comprises a plurality of acid gas discharge pipelines, the plurality of acid gas discharge pipelines are connected to a knockout drum through a main vent pipeline, the gas phase outlet of the knockout drum is connected to the elevated flare, and the liquid phase outlet of the knockout drum is connected to a condensate treatment tank through a condensate pump; the condensate treatment tank is at least provided with a condensate inlet and a sodium hypochlorite solution inlet; the distance between the knockout drum and the condensate treatment tank is 1 to 5 meters.

[0005] The beneficial effects of this invention are as follows: Research has shown that in traditional technology, elevated flares are in a state of combustion for extended periods, while waste gas and waste liquid are generated in the waste liquid recovery system, posing a risk of deflagration. Therefore, a distance of at least 90 meters is required between these two systems. Further research has revealed that the most corrosive and deflagration-risk substance in acidic gases is H2S, which has high water solubility. Addressing these characteristics of acidic gases, this invention utilizes H2S recovery treatment near the condensate separator, allowing the H2S-free condensate to be sent to the traditional waste liquid recovery system. This avoids the corrosion problem caused by prolonged storage or retention of H2S-containing condensate in the separator. Simultaneously, the condensate treatment tank enables timely recovery of sulfur from the condensate, effectively reducing safety risks and improving sulfur recovery efficiency compared to traditional technologies.

[0006] Preferably, the condensate treatment tank includes a treatment tank body, a heat exchange jacket on the outside of the treatment tank body, a stirring unit at the top center of the treatment tank body, a sodium hypochlorite solution inlet, a condensate inlet, a non-condensable gas outlet and a manhole on the top two sides of the treatment tank body, and a drain outlet at the bottom of the treatment tank body; the treatment tank body is also equipped with a level gauge and a pH sensor for detecting the liquid level and pH value of the solution inside the treatment tank body.

[0007] Preferably, the upper part of the heat exchange jacket is connected to a cooling water inlet, the bottom of the heat exchange jacket is provided with a condensate outlet, and the top of the heat exchange jacket is provided with an exhaust port.

[0008] Preferably, the stirring unit includes a stirring motor, which is connected to stirring blades via a stirring shaft extending into the interior of the processing tank body. A stirring baffle is provided on the inner wall of the processing tank body corresponding to the upper part of the stirring blades.

[0009] Preferably, the stirring baffle includes a bracket connected to the inner wall of the processing tank body, and the end of the bracket is connected to a baffle parallel to the inner wall of the processing tank body.

[0010] Preferably, a filter screen connected to the inner wall of the treatment tank body is provided between the lower part of the stirring blade and the drain port.

[0011] Preferably, the continuous light unit includes an air pipe and a fuel gas pipe, which are respectively connected to the inlet of the ignition plate, the outlet of the ignition plate is connected to the ignition port of the continuous light, and a first tee is provided between the fuel gas pipe and the inlet of the ignition plate, the third end of the first tee being connected to the gas supply port of the continuous light.

[0012] Preferably, the main discharge pipe is provided with a second tee, the third end of which is connected to the non-condensable gas outlet.

[0013] Preferably, a third tee is provided between the gas phase outlet of the separator and the elevated flare, and the third end of the third tee is connected to a nitrogen purging pipeline with a valve.

[0014] An acidic flare gas treatment system manufactured according to the above scheme can promptly treat H2S-containing condensate from the separator by setting up a condensate treatment tank near the separator. Compared with the traditional technology where the separator and waste liquid recovery system are far apart (a long distance inevitably leads to a long delivery pipeline, causing H2S-containing condensate to remain in the equipment and / or pipelines), this system not only avoids the corrosion problem caused by long-term storage or retention of H2S-containing condensate in the separator or corresponding pipelines, but also enables timely recovery of sulfur from the condensate, reducing safety risks and improving sulfur recovery efficiency. The newly designed condensate treatment tank can recover sulfur from H2S-containing condensate, increasing the amount of sulfur recovered. Simultaneously, due to the close proximity of the gas, it prevents H2S-containing condensate from remaining in related equipment. H2S-free condensate can enter the subsequent waste liquid recovery system for treatment, avoiding equipment corrosion. Furthermore, the condensate treatment tank allows waste gas to be returned to the separator while recovering sulfur. The above process avoids the generation of flammable and explosive waste gas and waste liquid. It has the advantages of reasonable process design, prevention of related equipment corrosion, effective reduction of safety risks, and improved sulfur recovery efficiency. Attached Figure Description

[0015] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0016] Figure 1 This is a schematic diagram of the structure of this utility model.

[0017] Figure 2 This is a schematic diagram of the condensate treatment tank of this utility model.

[0018] In the figure: 1. Elevated flare; 2. Acid gas discharge pipeline; 3. Main vent pipeline; 4. Liquid separation tank; 5. Nitrogen purging pipeline; 6. Condensate pump; 7. Treatment tank body; 8. Sodium hypochlorite solution inlet; 9. Condensate inlet; 10. Heat exchange jacket; 11. Non-condensable gas outlet; 12. Manhole; 13. Liquid discharge port; 14. Liquid level gauge; 15. pH sensor; 16. Steam inlet; 17. Condensate outlet; 18. Vent port; 19. Stirring motor; 20. Stirring shaft; 21. Stirring blade; 22. Bracket; 23. Baffle plate; 24. Filter screen; 25. Air pipeline; 26. Fuel gas pipeline; 27. Ignition disc; 28. Pilot burner; 29. First tee; 30. Second tee; 31. Third tee. Detailed Description of the Embodiments

[0019] The technical solutions in the embodiments of the present utility model will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by a person of ordinary skill in the art without creative work shall fall within the protection scope of the present utility model.

[0020] The following description is further detailed with reference to the accompanying Figure 1 2 The present application is further described in detail. The present utility model relates to an acid flare gas treatment system, which includes an elevated flare 1, a pilot burner unit matching the elevated flare 1, and an acid gas supply unit communicated with the elevated flare 1. The acid gas supply unit comprises a plurality of acid gas discharge pipelines 2, the plurality of acid gas discharge pipelines 2 are connected to a liquid separation tank 4 through a main vent pipeline 3, the gas phase outlet of the liquid separation tank 4 is connected to the elevated flare 1, and the liquid phase outlet of the liquid separation tank 4 is connected to a condensate treatment tank through a condensate pump 6. The condensate treatment tank is at least provided with a condensate inlet 9 and a sodium hypochlorite solution inlet 8. The distance between the liquid separation tank 4 and the condensate treatment tank is 1 to 5 meters. The present utility model is designed to address the characteristics of small and intermittent amount of condensate separated by the liquid separation tank in the prior art, and the problem that the distance between the liquid separation tank and the waste liquid recovery system is at least 90 meters, resulting in the H2S-containing condensate needing to stay in the liquid separation tank or the conveying pipeline and causing equipment corrosion. Specifically, by arranging the condensate treatment tank for receiving H2S-containing condensate near the liquid separation tank 4, the H2S-containing condensate can quickly enter the condensate treatment tank, and the sulfur in the condensate is recovered, so that the sulfur-recovered condensate enters the traditional waste liquid recovery system on the premise of no corrosiveness, thereby realizing the safe operation of the whole system and improving the sulfur recovery rate.

[0021] ​Furthermore, the condensate treatment tank includes a treatment tank body 7, with a heat exchange jacket 10 on the outside of the treatment tank body 7. A stirring unit is located at the top center of the treatment tank body 7. Sodium hypochlorite solution inlet 8, condensate inlet 9, non-condensable gas outlet 11, and manhole 12 are respectively located on both sides of the top of the treatment tank body 7. A drain outlet 13 is located at the bottom of the treatment tank body 7. The treatment tank body 7 is also equipped with a level gauge 14 and a pH sensor 15 for detecting the liquid level and pH value of the solution inside the treatment tank body 7. The condensate treatment tank described in this utility model is used to react H2S-containing condensate with sodium hypochlorite solution to generate sulfur. Its main principle is: NaClO + H2S = S↓ + NaCl + H2O. The above reaction process can directly generate sulfur precipitate, and the liquid phase is not corrosive. It can achieve safe, environmentally friendly, and stable operation of the entire equipment. The drain outlet 13 can transport the liquid phase to the subsequent waste liquid recovery system, thereby reducing the treatment load of the traditional waste liquid recovery system without changing the original treatment process. The processing tank body 7 and its internal equipment described in this utility model are preferably made of 316L stainless steel or carbon steel lined with PP (acid corrosion resistant).

[0022] Furthermore, the upper part of the heat exchange jacket 10 is connected to a cooling water inlet 16, the bottom of the heat exchange jacket 10 is provided with a condensate outlet 17, and the top of the heat exchange jacket 10 is provided with an exhaust port 18. This invention uses sodium hypochlorite solution. Since sodium hypochlorite solution is prone to decomposition when heated, the heat exchange jacket 10 is used to maintain the internal structure of the treatment tank body 7 to ensure stable reaction operation.

[0023] Furthermore, the stirring unit includes a stirring motor 19, which is connected to stirring blades 21 via a stirring shaft 20 extending into the processing tank body 7. A stirring baffle is provided on the inner wall of the processing tank body 7 corresponding to the upper part of the stirring blades 21. This arrangement enables the material to be evenly dispersed and achieves a more complete reaction.

[0024] Furthermore, the stirring baffle includes a bracket 22 connected to the inner wall of the processing tank body 7, and the end of the bracket 22 is connected to a baffle 23 parallel to the inner wall of the processing tank body 7.

[0025] Furthermore, a filter screen 24 connected to the inner wall of the treatment tank body 7 is provided between the lower part of the stirring blade 21 and the drain port 13. By setting the filter screen 24, sulfur can be filtered to intercept sulfur particles. Subsequently, the filter screen 24 can be removed and placed in a vibrating device to remove the sulfur, and the sulfur can be separated by a sedimentation tank or centrifuge.

[0026] Furthermore, the continuous light unit includes an air duct 25 and a fuel gas duct 26, which are respectively connected to the inlet of the ignition plate 27. The outlet of the ignition plate 27 is connected to the ignition port of the continuous light 28. A first T-junction 29 is provided between the fuel gas duct 26 and the inlet of the ignition plate 27, and the third end of the first T-junction 29 is connected to the gas supply port of the continuous light 28. This configuration ensures stable operation of the continuous light unit.

[0027] Furthermore, the main discharge pipe 3 is equipped with a second tee 30, the third end of which is connected to the non-condensable gas outlet 11. This arrangement allows the non-condensable gas in the treatment tank body 7 to enter the main discharge pipe 3 through the non-condensable gas outlet 11, and then enter the separatory tank 4 for further treatment.

[0028] Furthermore, a third tee 31 is provided between the gas phase outlet of the separator 4 and the elevated flare 1, and the third end of the third tee 31 is connected to a nitrogen purging pipe 5 with a valve.

[0029] The working principle of this invention is as follows: Acidic gas rich in H2S released from the production area enters the main discharge pipe 3 through its respective acidic gas discharge pipe 2, and then enters the separator 4. In the separator 4, the gas loses droplets with a diameter of 300-600 μm and enters the elevated flare 5, where it burns into a low-toxicity or non-toxic, non-flammable medium. The H2S-containing condensate after passing through the separator 4 is then pumped by the condensate pump 6 through the condensate inlet 9 into the treatment tank body 7. Sodium hypochlorite (NaClO) solution enters the treatment tank body 7 through the sodium hypochlorite solution inlet 8. Under the action of the stirring unit, the condensate and sodium hypochlorite solution are evenly dispersed and react, efficiently converting H2S into sulfur. The sulfur is intercepted by the filter screen 24 and transported to the transfer tank through the filtrate discharge port 13 of the filter screen 24. The waste liquid is further treated in a conventional wastewater recovery system (or it can be directly discharged, or used in a process water recycling system); the treatment tank body 7 and its internal equipment described in this utility model are preferably made of 316L stainless steel or carbon steel lined with PP (acid corrosion resistant). Since the decomposition of NaClO is greatly affected by temperature, a heat exchange jacket 10 is provided on the outside of the treatment tank body 7 to prevent NaClO from decomposing too quickly. The cooling water in the heat exchange jacket 10 adjusts the temperature inside the treatment tank body 7, maintaining the temperature of the material inside the treatment tank body 7 at 20-40℃. The gas phase produced during the heat exchange process can be discharged through the exhaust port 18; when the temperature inside the heat exchange jacket 10 is too high or sewage needs to be discharged during the heat exchange process, cooling water can be discharged through the condensate outlet 17; the reaction inside the treatment tank body 7 is under normal pressure, and the stirring unit stirs NaClO and H2S to fully contact and generate sulfur particles. The sulfur particles are deposited at the bottom of the treatment tank body 7 under gravity. A filter screen 24 (the filter screen 24 can be made of stainless steel) is installed at the bottom of the treatment tank body 7 to intercept the sulfur particles. The filter screen 24 can be periodically cleaned. Sulfur particles are recovered by replacing filter screen 24; the filtrate passing through filter screen 24 can be tested, and if further treatment is required, it can be sent to a traditional waste liquid recovery system. If it meets the discharge standards, it can be directly discharged or sent to the recycling system for reuse; unreacted H2S gas can enter the main discharge pipe 3 through the non-condensable gas outlet 11, and finally enter the separator 4 through the main discharge pipe 3 for reprocessing; this utility model has the advantages of reasonable process design, prevention of corrosion of related equipment, and prevention of low sulfur recovery rate caused by some H2S-containing condensate remaining in the pipeline.

[0030] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claimed utility model.

Claims

1. An acidic flare gas treatment system, comprising an elevated flare (1), a pilot burner unit matched with the elevated flare (1), and an acidic gas supply unit communicated with the elevated flare (1), characterized in that: The acid gas supply unit includes several acid gas discharge pipes (2), which are connected to the liquid separator (4) through the main discharge pipe (3). The gas phase outlet of the liquid separator (4) is connected to the overhead flare (1), and the liquid phase outlet of the liquid separator (4) is connected to the condensate treatment tank through the condensate pump (6). The condensate treatment tank is provided with at least a condensate inlet (9) and a sodium hypochlorite solution inlet (8); The distance between the liquid separator (4) and the condensate treatment tank is 1 to 5 meters.

2. The acidic flare gas treatment system according to claim 1, characterized in that: The condensate treatment tank includes a treatment tank body (7), a heat exchange jacket (10) is provided on the outside of the treatment tank body (7), a stirring unit is provided at the middle of the top of the treatment tank body (7), a sodium hypochlorite solution inlet (8), a condensate inlet (9), a non-condensable gas outlet (11) and a manhole (12) are provided on the top two sides of the treatment tank body (7), and a drain outlet (13) is provided at the bottom of the treatment tank body (7); the treatment tank body (7) is also provided with a level gauge (14) and a pH sensor (15) for detecting the liquid level and pH value of the solution inside the treatment tank body (7).

3. The acidic flare gas treatment system according to claim 2, characterized in that: The upper part of the heat exchange jacket (10) is connected to a cooling water inlet (16), the bottom of the heat exchange jacket (10) is provided with a condensate outlet (17), and the top of the heat exchange jacket (10) is provided with an exhaust port (18).

4. The acidic flare gas treatment system according to claim 2, characterized in that: The stirring unit includes a stirring motor (19), which is connected to a stirring blade (21) via a stirring shaft (20) extending into the processing tank body (7). A stirring baffle is provided on the inner wall of the processing tank body (7) corresponding to the upper part of the stirring blade (21).

5. The acidic flare gas treatment system according to claim 4, characterized in that: The stirring baffle includes a bracket (22) connected to the inner wall of the processing tank body (7), and the end of the bracket (22) is connected to a baffle (23) parallel to the inner wall of the processing tank body (7).

6. The acidic flare gas treatment system according to claim 4, characterized in that: A filter screen (24) connected to the inner wall of the treatment tank body (7) is provided between the lower part of the stirring blade (21) and the drain port (13).

7. The acidic flare gas treatment system according to claim 4, characterized in that: The continuous lamp unit includes an air duct (25) and a fuel gas duct (26). The air duct (25) and the fuel gas duct (26) are respectively connected to the inlet of the ignition plate (27). The outlet of the ignition plate (27) is connected to the ignition port of the continuous lamp (28). A first tee (29) is provided between the fuel gas duct (26) and the inlet of the ignition plate (27). The third end of the first tee (29) is connected to the gas supply port of the continuous lamp (28).

8. The acidic flare gas treatment system according to claim 2, characterized in that: The main discharge pipe (3) is provided with a second tee (30), and the third end of the second tee (30) is connected to the non-condensable gas outlet (11).

9. The acidic flare gas treatment system according to claim 1, characterized in that: A third tee (31) is provided between the gas phase outlet of the separator (4) and the elevated flare (1), and the third end of the third tee (31) is connected to a nitrogen purging pipe (5) with a valve.

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