Circulating liquid phase oxidation desulfurization device and process in absorption tower

Abstract

The invention relates to the technical field of gas desulfurization, and particularly discloses an absorption tower internal circulation liquid phase oxidation desulfurization device and process, the absorption tower internal circulation liquid phase oxidation desulfurization device comprises an absorption tower, the bottom of the absorption tower is a cone bottom outlet, the cone bottom outlet is connected with a flash tank or an oxidation tower through a main pipeline, and when the cone bottom outlet of the absorption tower is connected with the flash tank through the main pipeline, the oxidation tower is connected with the flash tank. The flash tank is connected with the oxidation tower through a pipeline; a cone bottom outlet of the absorption tower is connected with the upper portion of the absorption tower through an auxiliary pipeline, the auxiliary pipeline and the absorption tower form an inner circulation pipeline, and the flow speed of rich liquid at the cone bottom outlet of the absorption tower is increased to 2-4 m / s. The complex iron desulfurization solution in the absorption tower absorbs and oxidizes H2S in the raw material gas into elemental sulfur, so that the raw material gas is purified. By enhancing bottom disturbance of the absorption tower, the problem of blockage caused by sedimentation and attachment of sulfur particles to the bottom of the absorption tower can be avoided.

Description

Technical Field

[0001] The invention relates to the technical field of gas desulfurization, and in particular to a device and process for circulating liquid phase oxidation desulfurization in an absorption tower. Background Art

[0002] H2S is a toxic, corrosive, and malodorous gas that is commonly found in raw natural gas, oilfield associated gas, other industrial exhaust gases, and biogas. Weakly acidic H2S not only harms health and damages the environment, but also reduces the calorific value of natural gas and causes safety hazards such as corrosion of equipment and pipelines. At the same time, the improvement of environmental protection requirements and the popularization of environmental protection concepts have prompted green sustainability to become a new direction for the development of the chemical industry. In the fields of gas purification and atmospheric protection, the "Natural Gas Standard" (GB17820-2018), "Petroleum Refining Industry Pollutant Emission Standards", "Comprehensive Emission Standards for Atmospheric Pollutants" and other sulfide emission-related standards have put forward stricter requirements for gas purification and industrial waste gas emission standards. Corresponding natural gas desulfurization and purification technologies have been formed for raw natural gas with different sulfur contents and different gas volumes. For single-well natural gas containing sulfur, it is necessary to adopt it to meet the needs of effectively exerting the production capacity of single-well natural gas containing sulfur. The single-well desulfurization technology, which mainly uses complex iron liquid phase redox desulfurization, converts H2S into elemental sulfur through catalytic oxidation, realizing the function of sulfur recovery while achieving efficient purification of sour natural gas. It has shown high adaptability and economy in the production capacity of small-scale and low-potential sulfur (0.2-20t / d) natural gas pilot wells and remote dispersed gas wells. At the same time, because this technology has the characteristics of simple process, high desulfurization efficiency, safety and environmental protection, and low investment cost, it has developed rapidly in the field of gas desulfurization and purification, and is widely used in the purification of various hydrogen sulfide-containing gases such as refinery gas and synthetic ammonia industry.

[0003] Since its application in the 1970s, the complex iron liquid phase redox desulfurization technology has always had the risk of sulfur clogging equipment in engineering applications, and it has made it difficult for the desulfurization device to operate stably and efficiently for a long time. The complex iron liquid phase redox desulfurization technology is divided into conventional double-tower process and self-circulation process. The double-tower process mainly consists of key equipment such as absorption tower, oxidation tower, and circulation pump. The complex iron desulfurization solution in the absorption tower absorbs and oxidizes H2S in the raw gas into elemental sulfur, thereby purifying the raw gas. At the same time, the trivalent iron ions are reduced to ferrous ions; after the reaction, the rich liquid containing ferrous ions is oxidized to trivalent iron ions by air in the oxidation tower, realizing solvent regeneration and circulation. Due to the long process flow and more equipment in the double-tower process, the probability and risk of sulfur clogging equipment are higher. The fundamental reason for sulfur clogging is the hydrophobic sulfur S8 produced by the complex iron method. The sulfur particles are small and viscous and difficult to aggregate and grow. Sulfur plugging usually occurs in the most rapid and most sulfur-precipitating parts of the complex iron process. The newly generated sulfur has extremely small particle size and strong adhesion, and is easy to adhere to equipment or form sedimentation and compaction. The finer sulfur enters the regeneration zone, i.e., the oxidation zone, with the solution, and interacts with each other under the action of surfactants to form coarse flocculent particles, which settle from the degassing zone to the bottom of the cone to form sulfur slurry. This eventually leads to sulfur plugging at the bottom of key equipment such as absorption towers, oxidation towers, flash tanks, pulse purge air ducts, and air and acid gas nozzles and nozzles.

[0004] At present, the main method to alleviate the blockage of equipment is to optimize the complex iron desulfurization solution system and process design, such as using improved compound surfactants and related agents to control the sulfur morphology to improve the movement of sulfur particles in the solution system and reduce blockage; or using the reactor conical bottom design, adding factory wind purge at the bottom of the absorber cone, pipeline desalted water flushing and other process methods. However, the above methods are still difficult to effectively solve the problem of equipment being blocked by sulfur in engineering applications, especially there is currently no efficient method to prevent and solve the blockage of sulfur in the absorber. Summary of the invention

[0005] The object of the present invention is to provide a liquid-phase oxidation desulfurization device and process for circulating in an absorption tower, which can avoid the problem of sulfur particles settling and adhering to the bottom of the absorption tower to cause blockage by enhancing the disturbance at the bottom of the absorption tower.

[0006] The present invention is achieved through the following technical solutions:

[0007] An absorption tower internal circulation liquid phase oxidation desulfurization device comprises an absorption tower, the bottom of the absorption tower is a cone bottom outlet, the cone bottom outlet is connected to a flash tank or an oxidation tower through a main line, when the cone bottom outlet of the absorption tower is connected to the flash tank through the main line, the flash tank is connected to the oxidation tower through a pipeline;

[0008] The cone bottom outlet of the absorption tower is connected to the upper part of the absorption tower through a secondary pipeline. The secondary pipeline and the absorption tower form an internal circulation pipeline, which increases the rich liquid flow rate of the cone bottom outlet of the absorption tower to 2m / s to 4m / s. At this speed, the flow can be accelerated to avoid the accumulation of sulfur particles.

[0009] The complex iron desulfurization solution in the absorption tower of the present invention absorbs and oxidizes H2S in the raw gas to form elemental sulfur, thereby purifying the raw gas.

[0010] The present invention arranges a secondary pipeline through the cone bottom outlet of the absorption tower, so that the rich liquid flowing out of the cone bottom outlet of the absorption tower is divided into two paths, one path enters the oxidation tower directly or passes through the flash tank for oxidation treatment in the oxidation tower under the action of a pump or a pressure difference, and the other path returns to the absorption tower through the secondary pipeline, which is used to increase the flow rate of the rich liquid at the cone bottom outlet of the absorption tower, strengthen the fluidity of the sulfur slurry at the bottom of the tower, prevent and avoid the accumulation and adhesion of sulfur particles at the bottom of the absorption tower, and thus avoid the problem of blockage.

[0011] Furthermore, when the cone bottom outlet of the absorption tower is connected to the flash tank through the main line, a rich liquid pump for realizing the internal circulation of rich liquid is arranged on the auxiliary pipeline, and the rich liquid flowing out of the cone bottom outlet of the absorption tower flows to the flash tank through the pressure difference; when the cone bottom outlet of the absorption tower is connected to the oxidation tower through the main line, a rich liquid pump is arranged on the main line, one end of the auxiliary pipeline is connected to the main line and arranged at the rear end of the rich liquid pump, and the other end is connected to the upper part of the absorption tower, and the rich liquid flowing out of the cone bottom outlet of the absorption tower is pressurized by the rich liquid pump and enters the absorption tower and the oxidation tower.

[0012] Furthermore, a desalted water flushing pipeline is connected to the cone bottom outlet of the absorption tower, and the desalted water flushing pipeline is used to introduce desalted water or factory air into the cone bottom outlet of the absorption tower to dredge the pipeline.

[0013] That is, the outlet pipeline at the bottom of the absorber cone is connected to the desalted water flushing pipeline. The interface of the desalted water flushing pipeline should be as close to the outlet at the bottom of the absorber cone as possible. When blockage occurs, the pipeline can be cleared by introducing desalted water or factory air through the flushing pipeline.

[0014] Furthermore, the cone bottom outlet of the absorption tower is provided with a first three-way joint, and three interfaces of the first three-way joint are respectively connected to the cone bottom outlet of the absorption tower, the first flange and the main pipeline.

[0015] Furthermore, the diameter of the first flange connection pipeline is 65 mm to 200 mm.

[0016] Furthermore, the flow rate of the secondary pipeline is 50% to 100% of the flow rate of the primary pipeline.

[0017] Furthermore, it also includes a control unit;

[0018] The main line is provided with an electromagnetic valve, and the absorption tower is provided with a liquid level meter, the liquid level meter is used to collect the liquid level in the absorption tower and transmit the collected liquid level to a control unit, and the control unit controls the opening of the electromagnetic valve according to the collected liquid level.

[0019] Furthermore, the position where the secondary pipeline is connected to the absorption tower is 100% to 120% of the height of the lowest liquid level in the absorption tower.

[0020] Furthermore, the bottom of the flash tank is a cone bottom outlet, and the cone bottom outlet of the flash tank is provided with a second three-way joint, and the three interfaces of the second three-way joint are respectively connected to the cone bottom outlet of the flash tank, the second flange and the outlet pipeline, and the outlet pipeline is used to connect to the oxidation tower. The diameter of the second flange connection pipeline is 65mm to 200mm.

[0021] Furthermore, the bottom of the oxidation tower is a cone bottom outlet, and the cone bottom outlet of the oxidation tower is provided with a third three-way joint, and the three interfaces of the third three-way joint are respectively connected to the cone bottom outlet of the oxidation tower, the third flange and the sulfur slurry pump outlet pipeline, and the sulfur slurry pump outlet pipeline is provided with a sulfur slurry pump. The diameter of the third flange connection pipeline is 65mm to 200mm.

[0022] Further, the oxidation tower is connected with an oxidation air inlet pipeline and an oxidation air outlet pipeline;

[0023] The lower part of the oxidation tower is connected to the absorption tower through a liquid outlet pipeline, and a lean liquid pump is arranged on the liquid outlet pipeline;

[0024] The lower part of the oxidation tower is connected to the upper part of the oxidation tower through a pipeline, and a jet pump is arranged on the pipeline.

[0025] Based on the desulfurization process of the above-mentioned absorption tower circulating liquid phase oxidation desulfurization device, when used for high-pressure sour natural gas desulfurization, the raw natural gas enters the absorption tower, the absorption tower absorbs the raw natural gas, the raw natural gas H2S is oxidized into elemental sulfur, the purified natural gas is discharged from the absorption tower, and the rich liquid formed after absorbing and converting hydrogen sulfide is divided into two paths, one path enters the flash tank, and the other path returns to the absorption tower. The rich liquid at the bottom of the flash tank enters the oxidation tower, and the flash gas is discharged from the flash tank through a pipeline; the rich liquid is regenerated in the oxidation tower to form a lean liquid;

[0026] When used for desulfurization of low-pressure sour natural gas, the raw natural gas enters the absorption tower, the absorption tower absorbs the raw natural gas, the raw natural gas H2S is oxidized into elemental sulfur, the purified natural gas is discharged from the absorption tower, and the rich liquid formed after absorbing and converting hydrogen sulfide is divided into two paths, one path enters the oxidation tower, and the other path returns to the absorption tower; the rich liquid is regenerated in the oxidation tower to form lean liquid.

[0027] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0028] Compared with the conventional liquid-phase redox desulfurization process, by adding a circulating pipeline in the absorber, the flow rate at the bottom outlet of the absorber can be increased by 50% to 100%, which strengthens the fluidity of the sulfur slurry at the bottom of the tower and prevents and avoids the accumulation and adhesion of sulfur particles; by adding a desalted water flushing pipeline at the bottom outlet of the absorber, desalted water can be introduced to flush the absorber without stopping the operation to remove blockage; at the same time, three-way joints are added to the outlet pipelines of the absorber, flash tank, and oxidation tower, and one end of the three-way joint has a flange interface. When blockage occurs, the flange can be opened to clear the pipeline. The above three measures can prevent and solve the problem of sulfur blockage at the bottom of the liquid-phase redox desulfurization device. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings described herein are used to provide a further understanding of the embodiments of the present invention, constitute a part of this application, and do not constitute a limitation of the embodiments of the present invention. In the drawings:

[0030] Figure 1 This is a process flow chart of Example 1 of the present invention;

[0031] Figure 2 This is a process flow chart of Example 2 of the present invention.

[0032] Marks and corresponding parts names in the attached drawings:

[0033] 1-raw natural gas inlet pipeline, 2-absorption tower, 3-gas distributor, 4-purified gas outlet pipeline, 5-first flange, 6-rich liquid pump, 7-flash tank, 8-second flange, 9-flash gas outlet pipeline, 10-lean liquid pump, 11-jet pump, 12-oxidation tower, 13-third flange, 14-oxidation air inlet pipeline, 15-oxidation air outlet pipeline, 16-sulfur slurry pump, 17-export pipeline from sulfur slurry pump to downstream sulfur slurry filtration system, 18-desalted water flushing pipeline, 19-solenoid valve, 20-liquid level meter. DETAILED DESCRIPTION

[0034] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments and drawings. The exemplary embodiments of the present invention and their description are only used to explain the present invention and are not intended to limit the present invention.

[0035] Example:

[0036] A liquid-phase oxidation desulfurization device for circulation in an absorption tower comprises an absorption tower 2, which is connected to a raw natural gas inlet pipeline 1 and a purified gas outlet pipeline 4, wherein the purified gas outlet pipeline 4 is preferably arranged at the top of the absorption tower 2, and a gas distributor 3 connected to the raw natural gas inlet pipeline 1 is arranged in the absorption tower 2, the bottom of the absorption tower 2 is a cone bottom outlet, and the cone bottom outlet is connected to a flash tank 7 or an oxidation tower 12 through a main line, when the cone bottom outlet of the absorption tower 2 is connected to the flash tank 7 through the main line, the flash tank 7 is connected to the oxidation tower 12 through a pipeline; a flash gas outlet pipeline 9 is arranged on the flash tank 7, and the flash gas outlet pipeline 9 is preferably arranged at the top of the flash tank 7.

[0037] The cone bottom outlet of the absorption tower 2 is connected to the upper part of the absorption tower 2 through a secondary pipeline. The secondary pipeline and the absorption tower 2 form an internal circulation pipeline, which increases the rich liquid flow rate at the cone bottom outlet of the absorption tower 2 to 2m / s to 4m / s; the flow rate of the secondary pipeline is 10% to 70% of the flow rate of the main pipeline; the position where the secondary pipeline is connected to the absorption tower 2 is 100% to 120% of the height of the lowest liquid level in the absorption tower 2.

[0038] Wherein, the oxidation tower 12 is connected with an oxidation air inlet pipeline 14 and an oxidation air outlet pipeline 15;

[0039] The lower part of the oxidation tower 12 is connected to the absorption tower 2 through a liquid outlet pipeline, and a lean liquid pump 10 is provided on the liquid outlet pipeline;

[0040] The lower part of the oxidation tower 12 is connected to the upper part of the oxidation tower 12 through a pipeline, and a jet pump 11 is arranged on the pipeline.

[0041] When the cone bottom outlet of the absorption tower 2 is connected to the flash tank 7 through the main line, a rich liquid pump 6 for realizing the internal circulation of rich liquid is arranged on the auxiliary pipeline, and the rich liquid flowing out of the cone bottom outlet of the absorption tower 2 flows to the flash tank 7 through the pressure difference; when the cone bottom outlet of the absorption tower 2 is connected to the oxidation tower 12 through the main line, a rich liquid pump 6 is arranged on the main line, one end of the auxiliary pipeline is connected to the main line and is arranged at the rear end of the rich liquid pump 6, and the other end is connected to the upper part of the absorption tower 2, and the rich liquid flowing out of the cone bottom outlet of the absorption tower 2 is pressurized by the rich liquid pump 6 and enters the absorption tower 2 and the oxidation tower 12.

[0042] In a preferred case, the cone bottom outlet of the absorption tower 2 is connected to a desalted water flushing pipeline 18, and the desalted water flushing pipeline 18 is used to introduce desalted water or factory air into the cone bottom outlet of the absorption tower 2 to clear the pipeline.

[0043] In a preferred case, the cone bottom outlet of the absorption tower 2 is provided with a first three-way joint, and the three interfaces of the first three-way joint are respectively connected to the cone bottom outlet of the absorption tower 2, the first flange 5 and the main pipeline. The diameter of the pipeline connected to the first flange 5 is 65mm to 200mm.

[0044] In a preferred case, it also includes a control unit;

[0045] A solenoid valve 19 is provided on the main line, and a liquid level meter 20 is provided in the absorption tower 2. The liquid level meter 20 is used to collect the liquid level in the absorption tower 2 and transmit the collected liquid level to a control unit. The control unit controls the opening of the solenoid valve 19 according to the collected liquid level.

[0046] In a preferred case, the bottom of the flash tank 7 is a conical bottom outlet, and the conical bottom outlet of the flash tank 7 is provided with a second three-way joint, and the three interfaces of the second three-way joint are respectively connected to the conical bottom outlet of the flash tank 7, the second flange 8 and the outlet pipeline, and the outlet pipeline is used to connect to the oxidation tower 12.

[0047] In a preferred case, the bottom of the oxidation tower 12 is a conical bottom outlet, and the conical bottom outlet of the oxidation tower 12 is provided with a third three-way joint, and the three interfaces of the third three-way joint are respectively connected to the conical bottom outlet of the oxidation tower 12, the third flange 13 and the sulfur slurry pump outlet pipeline 17, and the sulfur slurry pump outlet pipeline 17 is provided with a sulfur slurry pump 16.

[0048] In this embodiment, by adding an internal circulation pipeline of the absorption tower 2, the flow rate of the cone bottom outlet of the absorption tower 2 can be increased by 50% to 100%, and the desalted water flushing pipeline 18 can be introduced into the desalted water to flush and unblock the absorption tower 2 without stopping the operation; at the same time, a three-way joint is added to the cone bottom outlet pipelines of the absorption tower 2, the flash tank 7, and the oxidation tower 12, and one end of the three-way joint has a flange interface. When blockage occurs, the flange can be opened to dredge the pipeline. The above three measures can prevent and solve the problem of sulfur blockage at the bottom of the liquid phase redox desulfurization device.

[0049] Embodiment 1:

[0050] like Figure 1As shown, the absorption tower internal circulating liquid phase oxidation desulfurization device is used for high-pressure (1.0-6.0 MPa) sour natural gas desulfurization, including an absorption tower 2, a flash tank 7, an oxidation tower 12, a rich liquid pump 6, a lean liquid pump 10, a jet pump 11, and a sulfur slurry pump 16. The cone bottom outlet pipelines of the absorption tower 2, the flash tank 7, and the oxidation tower 12 are respectively provided with a first three-way joint, a second three-way joint, and a third three-way joint. The first three-way joint, the second three-way joint, and one end of the third three-way joint are respectively provided with a first flange 5, a second flange 8, and a third flange 13. The absorption tower 2 is connected to a raw natural gas inlet pipeline 1 and a purified gas outlet pipeline 4. The gas distributor 3 in the absorption tower 2 is connected to the raw natural gas inlet pipeline 1. The desalted water flushing pipeline 18 is connected to the cone bottom outlet of the absorption tower 2. The cone bottom outlet main pipeline of the absorption tower 2 is connected to the flash tank 7. The cone bottom outlet auxiliary pipeline of the absorption tower 2 returns to the absorption tower 2 through the rich liquid pump 6, the flow rate of the cone bottom outlet auxiliary pipeline of the absorption tower 2 is 50% to 100% of the flow rate of the main pipeline, the cone bottom outlet auxiliary pipeline of the absorption tower 2 returns to the absorption tower 2 inlet at a height of 100% to 120% of the lowest liquid level of the absorption tower 2, the flash tank 7 is connected to the flash gas outlet pipeline 9, the cone bottom outlet pipeline of the flash tank 7 is connected to the oxidation tower 12, the oxidation tower 12 is connected to the oxidation air inlet pipeline 14 and the oxidation air outlet pipeline 15, the lower end of the oxidation tower 12 is connected to the liquid outlet pipeline connected to the lean liquid pump 10 and the jet pump 11, the outlet of the lean liquid pump 10 is connected to the upper end of the absorption tower 2 through a pipeline, the outlet of the jet pump 11 is connected to the upper end of the oxidation tower 12 through a pipeline, the cone bottom outlet pipeline of the oxidation tower 12 is connected to the sulfur slurry pump 16, and the sulfur slurry pump 16 is connected to the sulfur slurry pump outlet pipeline 17.

[0051] The process flow corresponding to this embodiment is as follows: when used for desulfurization of high-pressure sour natural gas, the raw natural gas enters the absorption tower 2, the absorption tower 2 absorbs the raw natural gas, the raw natural gas H2S is oxidized into elemental sulfur, the purified natural gas is discharged from the absorption tower 2, and the rich liquid formed after absorbing and converting hydrogen sulfide is divided into two paths, one path enters the flash tank 7, and the other path returns to the absorption tower 2, the rich liquid at the bottom of the flash tank 7 enters the oxidation tower 12, and the flash gas is discharged from the flash tank 7 through a pipeline; the rich liquid is regenerated in the oxidation tower 12 to form a lean liquid;

[0052] In this embodiment, the rich liquid flowing out of the bottom of the cone of the absorption tower 2 flows to the flash tank 7 through the pressure difference. The flow rate of the rich liquid flowing out of the bottom of the cone of the absorption tower 2 is the sum of the flow rate of the auxiliary pipeline rich liquid pump 6 and the flow rate to the flash tank 7. The flow rate of the internal circulation rich liquid is adjusted by the outlet valve of the rich liquid pump 6. It is more convenient to set the first flange 5, the second flange 8 and the third flange 13 as an eight-shaped blind plate or a quick-opening flange or a blind flange.

[0053] Embodiment 2:

[0054] like Figure 2As shown, the absorption tower internal circulating liquid phase oxidation desulfurization device is used for low-pressure (<1.0MPa) sour natural gas desulfurization, including an absorption tower 2, an oxidation tower 12, a rich liquid pump 6, a lean liquid pump 10, a jet pump 11, and a sulfur slurry pump 16. The absorption tower 2 and the oxidation tower 12 cone bottom outlet pipelines are respectively increased with a first three-way joint and a third three-way joint, and a first flange 5 and a third flange 13 are respectively arranged at one end of the first three-way joint and the third three-way joint. The absorption tower 2 is connected with a raw natural gas inlet pipeline 1 and a purified gas outlet pipeline 4. The gas distributor 3 in the absorption tower 2 is connected to the raw natural gas inlet pipeline 1, and the desalted water flushing pipeline 18 is connected to the absorption tower 2 cone bottom outlet. The absorption tower 2 cone bottom outlet pipeline is first connected to the rich liquid pump 6, and the outlet of the rich liquid pump 6 is divided into two pipelines. The outlet main pipeline of the rich liquid pump 6 is connected to the oxidation tower 12, the outlet auxiliary pipeline of the rich liquid pump 6 returns to the absorption tower 2, the flow rate of the outlet auxiliary pipeline of the rich liquid pump 6 is 50% to 100% of the flow rate of the main pipeline, the flow rate of the main pipeline from the outlet of the rich liquid pump 6 and the solenoid valve 19 to the oxidation tower 12 can be interlocked with the liquid level meter. The entrance height of the auxiliary pipeline of the rich liquid pump 6 returning to the absorption tower 2 is 100% to 120% of the height of the lowest liquid level of the absorption tower 2. The oxidation tower 12 is connected with an oxidation air inlet pipeline 14 and an oxidation air outlet pipeline 15. The lower end of the oxidation tower is connected to the liquid outlet pipeline connecting the lean liquid pump 10 and the jet pump 11. The outlet of the lean liquid pump 10 is connected to the upper end of the absorption tower 2 through a pipeline, and the outlet of the jet pump 11 is connected to the upper end of the oxidation tower 12 through a pipeline. The cone bottom outlet pipeline of the oxidation tower 12 is connected to the sulfur slurry pump 16, and the sulfur slurry pump 16 is connected to the sulfur slurry pump outlet pipeline 17.

[0055] The process flow corresponding to this embodiment is: when used for desulfurization of low-pressure sour natural gas, the raw natural gas enters the absorption tower 2, the absorption tower 2 absorbs the raw natural gas, the raw natural gas H2S is oxidized into elemental sulfur, and the purified natural gas is discharged from the absorption tower 2. The rich liquid formed after absorbing and converting hydrogen sulfide is divided into two paths, one path enters the oxidation tower 12, and the other path returns to the absorption tower 2; the rich liquid is regenerated in the oxidation tower 12 to form a lean liquid.

[0056] In this embodiment, the rich liquid flowing out of the bottom of the cone of the absorption tower 2 is divided into two paths after being pressurized by the rich liquid pump 6, flowing to the absorption tower 2 and the oxidation tower 12. The bottom flow of the absorption tower 2 is the sum of the flow of the auxiliary pipeline and the flow to the oxidation tower 12. The flow of the rich liquid at the bottom of the tower is adjusted by the solenoid valve 19 at the outlet of the rich liquid pump 6, and the flow to the oxidation tower 12 can be interlocked with the liquid level meter 20. It is more convenient to set the first flange 5 and the third flange 13 as an eight-shaped blind plate or a quick-opening flange or a blind flange.

[0057] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

[0058] It should be noted that the structures, proportions, sizes, etc. illustrated in the drawings of this specification are only used to match the contents disclosed in the specification for people familiar with this technology to understand and read, and are not used to limit the limiting conditions for the implementation of the present invention, so they have no substantial technical significance. Any modification of the structure, change of the proportional relationship or adjustment of the size should still fall within the scope of the technical content disclosed by the present invention without affecting the effects and purposes that can be achieved by the present invention. At the same time, the terms such as "upper", "lower", "left", "right", "middle" and the like cited in this specification are only for the convenience of description, and are not used to limit the scope of the implementation of the present invention. The change or adjustment of the relative relationship should also be regarded as the scope of the implementation of the present invention without substantially changing the technical content.

Claims

1. A liquid-phase oxidation desulfurization device circulating in an absorption tower, characterized in that: The absorber (2) comprises an absorber (2), wherein the bottom of the absorber (2) is a conical outlet, and the conical outlet is connected to a flash tank (7) or an oxidation tower (12) through a main line. When the conical outlet of the absorber (2) is connected to the flash tank (7) through the main line, the flash tank (7) is connected to the oxidation tower (12) through a pipeline. The cone bottom outlet of the absorption tower (2) is connected to the upper part of the absorption tower (2) through a secondary pipeline, and the secondary pipeline and the absorption tower (2) form an internal circulation pipeline to increase the rich liquid flow rate at the cone bottom outlet of the absorption tower (2) to 2 m / s to 4 m / s.

2. The absorption tower internal circulation liquid phase oxidation desulfurization device according to claim 1, characterized in that: When the cone bottom outlet of the absorption tower (2) is connected to the flash tank (7) through the main pipeline, a rich liquid pump (6) for realizing the internal circulation of rich liquid is arranged on the auxiliary pipeline, and the rich liquid flowing out of the cone bottom outlet of the absorption tower (2) flows to the flash tank (7) through the pressure difference; when the cone bottom outlet of the absorption tower (2) is connected to the oxidation tower (12) through the main pipeline, a rich liquid pump (6) is arranged on the main pipeline, one end of the auxiliary pipeline is connected to the main pipeline and arranged at the rear end of the rich liquid pump (6), and the other end is connected to the upper part of the absorption tower (2), and the rich liquid flowing out of the cone bottom outlet of the absorption tower (2) is pressurized by the rich liquid pump (6) and enters the absorption tower (2) and the oxidation tower (12).

3. The absorption tower internal circulation liquid phase oxidation desulfurization device according to claim 1, characterized in that: The cone bottom outlet of the absorption tower (2) is connected to a demineralized water flushing pipeline (18), and the demineralized water flushing pipeline (18) is used to introduce demineralized water or factory air into the cone bottom outlet of the absorption tower (2) to clear the pipeline.

4. The absorption tower internal circulation liquid phase oxidation desulfurization device according to claim 1, characterized in that: The cone bottom outlet of the absorption tower (2) is provided with a first three-way joint, and the three interfaces of the first three-way joint are respectively connected to the cone bottom outlet of the absorption tower (2), the first flange (5) and the main pipeline, and the first flange (5) is an eight-shaped blind plate or a quick-opening flange or a blind flange.

5. The absorption tower internal circulation liquid phase oxidation desulfurization device according to claim 4, characterized in that: The diameter of the pipeline connected to the first flange (5) is 65 mm to 200 mm.

6. The absorption tower internal circulation liquid phase oxidation desulfurization device according to claim 1, characterized in that: The flow rate of the secondary pipeline is 50% to 100% of the flow rate of the main pipeline.

7. The absorption tower internal circulation liquid phase oxidation desulfurization device according to claim 1, characterized in that: Also includes a control unit; The main line is provided with an electromagnetic valve (19), and the absorption tower (2) is provided with a liquid level meter (20). The liquid level meter (20) is used to collect the liquid level in the absorption tower (2) and transmit the collected liquid level to a control unit. The control unit controls the opening of the electromagnetic valve (19) according to the collected liquid level.

8. The absorption tower internal circulation liquid phase oxidation desulfurization device according to claim 1, characterized in that: The position where the secondary pipeline is connected to the absorption tower (2) is 100% to 120% of the height of the lowest liquid level in the absorption tower (2).

9. The absorption tower internal circulation liquid phase oxidation desulfurization device according to claim 1, characterized in that: The bottom of the flash tank (7) is a cone-bottom outlet, and the cone-bottom outlet of the flash tank (7) is provided with a second three-way joint, and the three interfaces of the second three-way joint are respectively connected to the cone-bottom outlet of the flash tank (7), the second flange (8) and the outlet pipeline, and the outlet pipeline is used to connect to the oxidation tower (12); the second flange (8) is an eight-shaped blind plate or a quick-opening flange or a blind flange.

10. The absorption tower internal circulation liquid phase oxidation desulfurization device according to claim 1, characterized in that: The bottom of the oxidation tower (12) is a cone-bottom outlet, and the cone-bottom outlet of the oxidation tower (12) is provided with a third three-way joint, and the three interfaces of the third three-way joint are respectively connected to the cone-bottom outlet of the oxidation tower (12), the third flange (13) and the sulfur slurry pump outlet pipeline (17), and the sulfur slurry pump outlet pipeline (17) is provided with a sulfur slurry pump (16); the third flange (13) is an eight-shaped blind plate or a quick-opening flange or a blind flange.

11. A desulfurization process based on the absorption tower internal circulation liquid phase oxidation desulfurization device according to any one of claims 1 to 10, characterized in that: When used for desulfurization of high-pressure sour natural gas, the raw natural gas enters the absorption tower (2), the absorption tower (2) absorbs the raw natural gas, and the H2S in the raw natural gas is oxidized into elemental sulfur. The purified natural gas is discharged from the absorption tower (2), and the rich liquid formed after absorbing and converting hydrogen sulfide is divided into two paths, one path enters the flash tank (7), and the other path returns to the absorption tower (2). The rich liquid at the bottom of the flash tank (7) enters the oxidation tower (12), and the flash gas is discharged from the flash tank (7) through a pipeline; the rich liquid is regenerated in the oxidation tower (12) to form a lean liquid; When used for desulfurization of low-pressure sour natural gas, the raw natural gas enters the absorption tower (2), the absorption tower (2) absorbs the raw natural gas, and the H2S in the raw natural gas is oxidized into elemental sulfur. The purified natural gas is discharged from the absorption tower (2), and the rich liquid formed after absorbing and converting hydrogen sulfide is divided into two paths, one of which enters the oxidation tower (12) and the other returns to the absorption tower (2); the rich liquid is regenerated in the oxidation tower (12) to form a lean liquid.

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