Hydrogen sulfide-containing tail gas treatment system

Abstract

The utility model discloses a hydrogen sulfide-containing tail gas treatment system which comprises a mixed gas pipeline, after mixed gas is decompressed by a decompression tank and filtered by a coalescence filter, condensate is discharged into a collection pipe network, the filtered mixed gas enters an absorption reactor for desulfurization, generated desulfurized mixed dry gas passes through a desulfurized gas liquid separation tank, and then discharged desulfurized dry gas is sent to a burner pipe network. A CTS catalyst is contained in the absorption reactor, H2S in the mixed dry gas is absorbed by a solution and oxidized into elemental sulfur particles to be removed, and the solution at the bottom of the absorption reactor is discharged to the absorption / oxidation reactor under the action of the pressure of the solution and is oxidized by an acid gas to regenerate the catalyst. According to the hydrogen sulfide-containing tail gas treatment system, after gas of the stripping tower and the low-pressure separation tank is treated by the sulfur recovery device, the H2S content of tail gas purified by the device is smaller than or equal to 20 mg / Nm < 3 >, the tail gas can enter a fuel gas system for combustion for reasonable utilization, the national emission standard is met, and the produced sulfur can be sold.

Description

Technical Field

[0001] The utility model relates to the technical field of hydrogen sulfide-containing tail gas treatment. Background Technique

[0002] The treatment of hydrogen sulfide refers to the recovery, utilization or harmless treatment of hydrogen sulfide (H2S) discharged in the industrial production process by applying methods such as absorption, adsorption and catalytic oxidation. Hydrogen sulfide is generated in the processes of natural gas purification, petroleum refining, and the production of coal gas, leather making, pharmaceuticals, paper making, synthetic chemical fibers, etc. Hydrogen sulfide is a colorless gas with a pungent odor, volatile, and burns with a blue flame. Hydrogen sulfide is one of the main pollutants in the atmosphere, which not only endangers human health but also seriously corrodes equipment, etc.

[0003] Since the hydrogen sulfide content in the gas withdrawn from the stripping tower and the low-pressure separator is 6000 ppm to 8000 ppm and is discharged through the flare, firstly, the emission of the first combustible gas is an economic loss to the enterprise, and secondly, it does not meet the emission standard requirements and is a pollution to the environment. Therefore, the mixed gas withdrawn from the stripping tower and the low-pressure separator is treated to meet the emission standard and a part of it is recovered. Content of the Utility Model

[0004] The purpose of the utility model is to provide a hydrogen sulfide-containing tail gas treatment system to solve the problems put forward in the above background technique.

[0005] To achieve the above purpose, the utility model provides the following technical solutions:

[0006] The hydrogen sulfide-containing tail gas treatment system includes a mixed gas pipeline. After the mixed gas is depressurized by a pressure reducing tank and filtered by a coalescing filter, the condensate is discharged into the collection pipeline network. The filtered mixed gas enters the absorption reactor for desulfurization, and the desulfurized dry gas generated is sent to the burner pipeline network after passing through the desulfurized gas separation tank. The absorption reactor is equipped with a CTS catalyst, and the H2S in the mixed dry gas is absorbed by the solution and oxidized to form elemental sulfur particles for removal.

[0007] As a further scheme of the utility model: The solution at the bottom of the absorption reactor is discharged to the absorption / oxidation reactor under the action of its own pressure, and the catalyst is regenerated by the acid gas oxidation gas. The regenerated solution is pumped into the absorption reactor through a circulation pump for reuse.

[0008] As a further scheme of the utility model: The H2S in the acid gas is absorbed by the solution and oxidized into elemental sulfur particles. Oxidation gas is introduced to oxidize the divalent Fe2+ ions reduced by hydrogen sulfide in the catalyst solution into trivalent Fe3+ ions, so that the catalyst can be regenerated and reused repeatedly for regeneration.

[0009] As a further solution of the present utility model: a solution heating / cooling system is configured for the regenerated solution, and the heating / cooling system is a heat exchanger. The medium exchanges heat with the regenerated solution in the heat exchanger to maintain the regenerated solution at 50°C.

[0010] As a further solution of the present utility model: the elemental sulfur particles in the absorption / oxidation reactor are sent to a sulfur filter to form sulfur cakes and filtrate. The filtrate is temporarily stored in a filtrate tank and sent back to the absorption / oxidation reactor through a reflux pump.

[0011] As a further solution of the present utility model: the absorption / oxidation reactor includes a shell. The interior of the shell is divided into a degassing zone, an absorption zone, a reaction zone, and a regeneration zone by baffle plates and overflow plates. The absorption / oxidation reactor is provided with a circulating slurry pipeline, an acidic gas pipeline, an oxidation gas pipeline, a spray solution pipeline, a chemical injection pipeline, a filtrate inlet, and a solution inlet. The circulating slurry pipeline extends to the degassing zone, the chemical injection pipeline, the acidic gas pipeline, the filtrate inlet, and the solution inlet extend to the absorption zone, and the oxidation gas pipeline and the spray solution pipeline extend to the regeneration zone.

[0012] As a further solution of the present utility model: the baffle plates include baffle plate I and baffle plate II, and the overflow plates include overflow plate I and overflow plate II. Overflow plate I is between the regeneration zone and the degassing zone, baffle plate II is between the degassing zone and the absorption zone, overflow plate II is between the absorption zone and the reaction zone, baffle plate I is between the reaction zone and the regeneration zone, and the side of the absorption zone close to the regeneration zone is sealed.

[0013] As a further solution of the present utility model: distributors are provided at the output ends of both the oxidation gas pipeline and the chemical injection pipeline.

[0014] Compared with the prior art, the beneficial effects of the present utility model are:

[0015] For this hydrogen sulfide-containing tail gas treatment system, after the stripping tower and the gas from the low-pressure separator are treated by the sulfur recovery unit, the H2S content in the purified tail gas of the unit is ≤20 mg / Nm3. Firstly, it can be reasonably utilized by being sent to the fuel gas system for combustion. Secondly, it also meets the emission standards. Thirdly, the produced sulfur can be sold externally. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic structural diagram of a hydrogen sulfide-containing tail gas treatment system;

[0017] Figure 2 It is a schematic structural diagram of an absorption / oxidation reactor in a hydrogen sulfide-containing tail gas treatment system;

[0018] Figure 3 It is a top view of the structure of an absorption / oxidation reactor in a hydrogen sulfide-containing tail gas treatment system;

[0019] Figure 4 It is a schematic structural diagram of a baffle in a hydrogen sulfide-containing tail gas treatment system.

[0020] In the figure: 1. Shell; 2. Oxidation gas pipeline; 3. Distributor; 4. Spraying solution pipeline; 5. Chemical agent injection pipeline; 6. Filtrate inlet; 7. Solution inlet; 8. Baffle I; 9. Overflow plate I; 10. Baffle II; 11. Overflow plate II; 12. Degassing zone; 13. Absorption zone; 14. Reaction zone; 15. Regeneration zone; 16. Circulating slurry pipeline; 17. Acid gas pipeline. Specific implementation manners

[0021] Please refer to Figures 1 to 4 , in the embodiment of the present utility model, the hydrogen sulfide-containing tail gas treatment system includes a mixed gas pipeline. The condensate of the mixed gas is discharged into the collection pipe network after being depressurized by a pressure reducing tank and filtered by a coalescing filter. The filtered mixed gas enters an absorption reactor for desulfurization. The desulfurized mixed dry gas generated is sent to the burner pipe network after passing through a desulfurized gas knockout drum. The absorption reactor is provided with a CTS catalyst. H2S in the mixed dry gas is absorbed by the solution and oxidized to form elemental sulfur particles and removed. The mixed gas from the low-pressure separator outside the battery limit continuously exhausting gas and the intermittent exhaust gas from the top of the stripping column is depressurized and then the hydrocarbons entrained therein are removed through a coalescing filter. The liquid, oil, and acidic condensate will be periodically discharged from the coalescing filter to the underground waste oil collection pipe network. The filtered mixed gas enters the absorption reactor for desulfurization treatment. In the absorption reactor, the mixed gas of the exhaust gas from the low-pressure separator and the gas discharged from the top of the stabilizer enters the CTS catalyst solution through the gas distributor at the bottom of the absorption reactor. H2S in the mixed dry gas is absorbed by the solution and oxidized to form elemental sulfur particles and removed. The desulfurized mixed dry gas enters the desulfurized gas knockout drum. The liquid and flushing water separated by the knockout drum are directly discharged to the absorption reactor by gravity. The desulfurized dry gas discharged from the top of the desulfurized gas knockout drum, with its H2S content not exceeding 20 mg / Nm3, is discharged to the factory fuel gas pipe network.

[0022] In a preferred embodiment, the solution at the bottom of the absorption reactor is discharged to the absorption / oxidation reactor under its own pressure, and the catalyst is regenerated by the acid gas oxidation gas. The regenerated solution is pumped into the absorption reactor through a circulation pump for reuse. H2S in the acid gas is absorbed by the solution and oxidized into elemental sulfur particles. Oxidation gas is introduced to oxidize the divalent Fe2+ ions reduced by hydrogen sulfide in the catalyst solution into trivalent Fe3+ ions, so that the catalyst can be regenerated and reused repeatedly. The solution at the bottom of the absorption reactor is discharged to the absorption / oxidation reactor for regeneration under its own pressure. The continuous exhaust gas of the acid gas directly enters the bottom of the absorption zone of the absorption oxidation reactor, and is diffused and distributed into bubbles through the acid gas distributor and enters the solution. H2S in the acid gas is absorbed by the solution and oxidized into elemental sulfur particles. The absorption / oxidation reactor is divided into different zones such as an absorption zone, a reaction zone, and an oxidation zone. By introducing the oxidation air and the acid gas, a density difference is generated in the solution among different zones, forming a circulation of the solution in different zones in the absorption / oxidation reactor. The oxidation regeneration of the solution is carried out in the absorption / oxidation reactor. Taking purified air as the regeneration air, it enters the bottom of the regeneration zone of the absorption / oxidation reactor. The distributor is used to disperse the air into tiny bubbles and enter the solution and move upward, oxidizing the divalent Fe2+ ions reduced by hydrogen sulfide in the catalyst solution into trivalent Fe3+ ions, so that the catalyst can be regenerated and reused repeatedly. The regenerated solution returns to the absorption reactor through the solution circulation pump for desulfurization of the mixed gas.

[0023] In a preferred embodiment, a solution heating / cooling system is configured for the regenerated solution. The heating / cooling system is a heat exchanger. The medium exchanges heat with the regenerated solution in the heat exchanger to keep the regenerated solution at 50°C. In order to keep the temperature of the catalyst solution system at 50°C, a solution heating / cooling system is set up. According to the operating and environmental conditions of the factory, the solution is heated or cooled through the solution heat exchanger. In order to prevent sulfur from melting at high temperatures, hot water at about 90°C transported by a hot water pump is used for heating when the solution is heated.

[0024] In a preferred embodiment, the elemental sulfur particles in the absorption / oxidation reactor are fed into a sulfur filter to form a sulfur cake and filtrate. The filtrate is temporarily stored in a filtrate tank and fed into the absorption / oxidation reactor through a reflux pump. The elemental sulfur generated in the solution is in the form of fine particles and suspended in the catalyst solution. According to the amount of sulfur generated by the reaction, the sulfur particles need to be separated through a sulfur filtration system. The sulfur slurry pumped out from the bottom of the absorption / oxidation reactor enters the sulfur filter. The sulfur slurry is filtered and dehydrated to produce a sulfur cake containing 35 wt% water. The filtrate enters the filtrate return tank and is sent to the absorption and oxidation reactor through a filtrate return pump. NH3 in the acid gas is absorbed by the solution, making the catalyst solution weakly alkaline to maintain the alkaline conditions required for the normal desulfurization reaction of the solution. No additional alkali solution needs to be supplemented during the normal operation of the system. During the normal operation process, a small amount of iron catalyst, chelating agent, etc. in the solution will be lost with the discharge of sulfur, and part of the chelating agent will also decompose. Therefore, replenishment is required. At the same time, a bactericide and a surfactant also need to be added to the solution in the reactor during operation to maintain stable operation. Various catalysts and chemical agents are stored in reagent barrels or tanks and are added to the regenerator through metering pumps.

[0025] In a preferred embodiment, the absorption / oxidation reactor includes a housing 1. The interior of the housing 1 is divided into a degassing zone 12, an absorption zone 13, a reaction zone 14, and a regeneration zone 15 by baffle plates and overflow plates. The absorption / oxidation reactor is provided with a circulating slurry pipeline 16, an acid gas pipeline 17, an oxidation gas pipeline 2, a spray solution pipeline 4, a chemical agent addition pipeline 5, a filtrate inlet 6, and a solution inlet 7. The circulating slurry pipeline 16 extends to the degassing zone 12, and the chemical agent addition pipeline 5, the acid gas pipeline 17, the filtrate inlet 6, and the solution inlet 7 extend to the absorption zone 13. The oxidation gas pipeline 2 and the spray solution pipeline 4 extend to the regeneration zone 15.

[0026] In a preferred embodiment, the baffle plates include baffle plate I 8 and baffle plate II 10, and the overflow plates include overflow plate I 9 and overflow plate II 11. There is overflow plate I 9 between the regeneration zone 15 and the degassing zone 12, baffle plate II 10 between the degassing zone 12 and the absorption zone 13, overflow plate II 11 between the absorption zone 13 and the reaction zone 14, and baffle plate I 8 between the reaction zone 14 and the regeneration zone 15. One side of the absorption zone 13 close to the regeneration zone 15 is sealed.

[0027] In a preferred embodiment, distributors 3 are provided at the output ends of both the oxidation gas pipeline 2 and the chemical agent addition pipeline 5.

[0028] It should be noted that the above embodiments all belong to the same inventive concept of the utility model. The descriptions of the embodiments have their own focuses. For the parts not described in detail in individual embodiments, reference can be made to the descriptions in other embodiments.

[0029] The above-described embodiments merely represent the implementation manners of the present utility model. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the scope of the utility model patent. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present utility model, several variations and improvements can still be made, and these all fall within the protection scope of the present utility model. Therefore, the protection scope of the present utility model patent shall be subject to the appended claims.

Claims

1. A hydrogen sulfide-containing tail gas treatment system, characterized in that, It includes a mixed gas pipeline. After the mixed gas is depressurized by a pressure reducing tank and filtered by a coalescing filter, the condensate is discharged into the collection pipe network. The filtered mixed gas enters the absorption reactor for desulfurization. The desulfurized dry gas generated is sent to the burner pipe network after passing through the desulfurized gas liquid separation tank. There is a CTS catalyst in the absorption reactor, and H2S in the mixed dry gas is absorbed by the solution and oxidized to form elemental sulfur particles and removed.

2. The hydrogen sulfide-containing tail gas treatment system according to claim 1, wherein The solution at the bottom of the absorption reactor is discharged to the absorption / oxidation reactor under the action of its own pressure, and the catalyst is regenerated by the acid gas oxidizing gas. The regenerated solution is pumped into the absorption reactor through a circulation pump for reuse.

3. The hydrogen sulfide-containing tail gas treatment system according to claim 2, wherein H2S in the acid gas is absorbed by the solution and oxidized to elemental sulfur particles. An oxidizing gas is introduced to oxidize the divalent Fe2+ ions reduced by hydrogen sulfide in the catalyst solution into trivalent Fe3+ ions, so that the catalyst can be regenerated and reused repeatedly for regeneration.

4. The hydrogen sulfide-containing tail gas treatment system according to claim 2, wherein A solution heating / cooling system is configured for the regenerated solution. The heating / cooling system is a heat exchanger, and the medium exchanges heat with the regenerated solution in the heat exchanger to keep the regenerated solution at 50°C.

5. The hydrogen sulfide-containing tail gas treatment system according to claim 2, wherein The elemental sulfur particles in the absorption / oxidation reactor are sent to a sulfur filter to form sulfur cakes and filtrate. The filtrate is temporarily stored in a filtrate tank and sent back to the absorption / oxidation reactor through a reflux pump.

6. The hydrogen sulfide-containing tail gas treatment system according to claim 2, wherein, The absorption / oxidation reactor includes a shell (1). The interior of the shell (1) is separated into a degassing zone (12), an absorption zone (13), a reaction zone (14), and a regeneration zone (15) by baffle plates and overflow plates. The absorption / oxidation reactor is provided with a circulating slurry pipeline (16), an acid gas pipeline (17), an oxidation gas pipeline (2), a spray solution pipeline (4), a chemical injection pipeline (5), a filtrate inlet (6), and a solution inlet (7). The circulating slurry pipeline (16) extends to the degassing zone (12), and the chemical injection pipeline (5), the acid gas pipeline (17), the filtrate inlet (6), and the solution inlet (7) extend to the absorption zone (13). The oxidation gas pipeline (2) and the spray solution pipeline (4) extend to the regeneration zone (15).

7. The hydrogen sulfide-containing tail gas treatment system according to claim 6, wherein, The baffle plates include baffle plate I (8) and baffle plate II (10), and the overflow plates include overflow plate I (9) and overflow plate II (11). There is overflow plate I (9) between the regeneration zone (15) and the degassing zone (12), baffle plate II (10) between the degassing zone (12) and the absorption zone (13), overflow plate II (11) between the absorption zone (13) and the reaction zone (14), and baffle plate I (8) between the reaction zone (14) and the regeneration zone (15). One side of the absorption zone (13) close to the regeneration zone (15) is sealed.

8. The hydrogen sulfide-containing tail gas treatment system according to claim 6, wherein Distributors (3) are provided at the output ends of the oxidation gas pipeline (2) and the chemical injection pipeline (5).

Images