Process for absorbing low-content hydrogen sulfide gas

Abstract

The invention discloses a process for absorbing low-content hydrogen sulfide gas, which comprises the following steps of: introducing feed gas containing hydrogen sulfide into a packed bed in a supergravity reactor, introducing a polar solvent into the middle part of the supergravity reactor, and enabling the polar solvent to be in reverse contact with the feed gas, so that the polar solvent absorbs a large amount of hydrogen sulfide gas; non-polar gases such as carbon dioxide are directly discharged, and the polar solvent continuously flows towards the outer ring of the packed bed and is mixed and contacted with the desulfurizing agent for reaction and desulfurization. According to the invention, carbon dioxide reacting with the desulfurizing agent is separated in advance, so that the problem of competitive reaction of carbon dioxide is avoided, the use cost of the desulfurizing agent is reduced, and the desulfurizing effect is improved.

Description

Technical Field

[0001] The invention relates to the technical field of desulfurization, in particular to a process for absorbing low-content hydrogen sulfide gas. Background Art

[0002] The chemical production process of rubber accelerators requires heating of the reaction, and boilers are usually used for steam heat transfer and temperature control. A small amount of acidic gases such as hydrogen sulfide will be produced during the combustion of gas and the reaction process, which must be discharged after desulfurization. There are many desulfurization methods, including Claus method, iron oxide method, alcohol amine method, and low-temperature methanol washing method. Among them, the alcohol amine method is favored by enterprises because of its high desulfurization efficiency, regeneration and recycling, and low cost. The alcoholamine method uses methyldiethanolamine, triethanolamine, etc. as absorbents, which react quickly with hydrogen sulfide, carbon dioxide acid gas and other sulfur-containing impurities to generate acid sulfide amine salts (or acid carbonate amine salts). When the temperature rises, the generated amine salts decompose again to release hydrogen sulfide and carbon dioxide gas. The removed hydrogen sulfide is sent to the sulfur recovery device to be converted into sulfur, and the amine liquid is recycled. The alcoholamine method is suitable for the treatment of high-content hydrogen sulfide gas, but not for the treatment of low-content hydrogen sulfide gas. The reason is that low-content hydrogen sulfide gas contains a large amount of carbon dioxide, which will react with a large amount of amine liquid, increasing the cost of the absorbent. Therefore, this method must remove part of the carbon dioxide before it can be used.

[0003] Patent 202310687953.9 discloses a selective desulfurization method based on a supergravity reactor. The packing bed of the supergravity reactor is set as multiple annular packing areas, and multiple guide members are evenly distributed in the annular grooves between adjacent packing areas. The guide members can change the flow direction of the desulfurizer liquid after passing through the inner packing area, forming multiple end effect areas, reducing the gas-liquid contact time, thereby reducing the absorption of carbon dioxide. However, this method will also simultaneously reduce the contact time of hydrogen sulfide gas, and the desulfurization effect is poor, which needs further improvement. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and provide a process for absorbing low-content hydrogen sulfide gas to solve the problem of large amounts of carbon dioxide competing with large amounts of amine liquid in the desulfurization reaction.

[0005] The objective of the present invention is achieved through the following technical scheme: a process for absorbing low-content hydrogen sulfide gas, wherein a raw gas containing hydrogen sulfide is introduced into a packed bed in a supergravity reactor, a polar solvent is introduced into the middle of the supergravity reactor, the polar solvent is brought into reverse contact with the raw gas, the polar solvent absorbs a large amount of hydrogen sulfide gas, non-polar gases such as carbon dioxide are directly discharged, the polar solvent continues to flow toward the outer ring of the packed bed, and is mixed with a desulfurizer for contact reaction and desulfurization.

[0006] Preferably, the polar solvent is selected from one or more of anhydrous methanol and anhydrous ethanol, and the desulfurizing agent is selected from one or more of ethanolamine and methyldiethanolamine.

[0007] Preferably, the ultra-gravity reactor comprises a container provided with a liquid outlet and a packing bed rotating inside the container, wherein a first packing area, a separation tube and a second packing area are arranged in the packing bed, and the first packing area and the second packing area are both annular structures, and the first packing area, the separation tube and the second packing area are concentrically nested in sequence, and the first packing area and the middle part of the container form a feed chamber, and the feed chamber is provided with a first liquid inlet pipe and a first gas outlet pipe, and the first liquid inlet pipe and the first gas outlet pipe are connected to the feed chamber, and a gas-liquid separation chamber is arranged between the first packing area and the separation tube, and a raw gas inlet is arranged at the top of the gas-liquid separation chamber, and a mixing chamber is arranged between the second packing area and the separation tube, and a desulfurizer inlet is arranged in the mixing chamber, and a liquid passage is arranged at the bottom of the mixing chamber and the gas-liquid separation chamber for communication.

[0008] Preferably, a filter cartridge is provided in the packing bed, a plurality of filter holes are provided on the filter cartridge, and the filter cartridge is concentrically arranged between the separation cartridge and the second packing area.

[0009] Preferably, the liquid passage is a circular ring structure with a U-shaped cross section.

[0010] Preferably, the liquid outlet end of the liquid passage extends upward to form a double-annular convex edge, and the desulfurizing agent inlet extends into the inner ring of the convex edge.

[0011] Preferably, a driving mechanism is provided on the packing bed, and the driving structure drives the second packing area to move up and down with the convex edge as the amplitude center.

[0012] Preferably, the driving mechanism includes a sliding rod, a roller, a spring, and an adjustment plate, the spring is located between the bottom surface of the second filling area and the filling bed, the axis of the roller is rotatably connected to the top of the sliding rod, the bottom end of the sliding rod passes through the top surface of the filling bed and is slidably connected to the filling bed, the bottom end of the sliding rod is fixedly connected to the second filling area, the adjustment plate is annular, the adjustment plate is coaxially arranged with the filling bed, the adjustment plate is fixedly connected to the container, the bottom surface of the adjustment plate is wavy, and the bottom surface of the adjustment plate is in contact with the roller.

[0013] Preferably, the gas-liquid separation chamber is provided with a first air outlet tube and a sealing cover, an annular air passage is provided in the first air outlet tube, the sealing cover is rotatably sealed and connected to the upper part of the first air outlet tube, an air inlet is provided on the sealing cover, and the air inlet is connected to the annular air passage.

[0014] The present invention has the following advantages:

[0015] 1. Provide a desulfurization method capable of treating low-content hydrogen sulfide gas. Direct reaction of raw gas with high carbon dioxide content and low hydrogen sulfide content with amine liquid will consume a large amount of desulfurizer. By first mixing the raw gas with a polar solvent, the solubility of hydrogen sulfide in polar solvent is higher than that of carbon dioxide, so that a large amount of hydrogen sulfide is dissolved in the polar solvent, and non-polar gases such as carbon dioxide are directly discharged without pollution, so that hydrogen sulfide and carbon dioxide are separated in advance, and then the desulfurizer is reacted with hydrogen sulfide gas, thereby avoiding the problem of competitive consumption of desulfurizer by carbon dioxide relative to hydrogen sulfide, and reducing the use cost of desulfurizer;

[0016] 2. Provide an ultra-gravity reactor that can be adapted to the desulfurization method of separating carbon dioxide in advance, which can desulfurize low-content hydrogen sulfide gas in an integrated and continuous manner, with good separation effect and high desulfurization efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a process flow chart of the present invention;

[0018] Figure 2 is a schematic cross-sectional structural diagram of embodiment 1 of the present invention;

[0019] Figure 3 is a schematic cross-sectional structural diagram of embodiment 2 of the present invention;

[0020] Figure 4 yes Figure 3 The enlarged schematic diagram of point A in the middle;

[0021] Figure 5 It is a schematic diagram of the expanded structure of the adjustment plate.

[0022] In the figure, 1, container; 2, packing bed; 3, rotating shaft; 4, partition cylinder; 5, first packing area; 6, second packing area; 7, feed chamber; 8, gas-liquid separation chamber; 9, mixing chamber; 10, filter cylinder; 11, filter hole; 12, first liquid inlet pipe; 13, first air outlet pipe; 14, sealing plate; 15, first air outlet cylinder; 16, sealing cover; 17, air inlet; 18, second liquid inlet cylinder; 19, second liquid inlet; 20, liquid outlet; 21, convex edge; 22, sliding rod; 23, adjusting plate; 24, roller; 25, spring; 26, liquid passage; DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0024] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0025] A process for absorbing low-content hydrogen sulfide gas, which is suitable for treating high-content carbon dioxide and low-content hydrogen sulfide gas. Although carbon dioxide is an acidic gas, its molecular structure is symmetrical and it is a non-polar molecule like oxygen and nitrogen. Hydrogen sulfide is a polar molecule like water. According to the principle of similar dissolution, polar molecules are easily dissolved in polar solvents, and non-polar molecules are easily dissolved in non-polar solvents. Non-polar molecules such as carbon dioxide, nitrogen, and oxygen are insoluble or difficult to dissolve in polar solvents, and hydrogen sulfide is easily soluble in polar solvents. Here, the polar solvent is selected from one or more of anhydrous methanol and anhydrous ethanol. The price is simple, the materials are easy to obtain, and it is convenient for later separation. Of course, other solvents can also be selected. It is necessary to ensure that the polar solvent does not react with the desulfurizer. The desulfurizer is selected from one or more of ethanolamine and methyldiethanolamine. Similarly, other amine liquids can also be selected. The process steps are as follows: Figure 1 As shown:

[0026] 1. Pass the raw gas with high carbon dioxide content and low hydrogen sulfide content into the polar solvent;

[0027] 2. Polar solvent absorbs hydrogen sulfide gas, other non-polar gases are directly discharged, carbon dioxide acid gas is separated, and hydrogen sulfide gas is recovered;

[0028] 3. The polar solvent is mixed with the desulfurizer to allow the desulfurizer to react with the hydrogen sulfide gas.

[0029] The details are as follows: a raw gas containing hydrogen sulfide is introduced into the packed bed 2 in the supergravity reactor, and the raw gas moves from the inlet to the center of the packed bed 2. A polar solvent is introduced into the middle of the supergravity reactor to make the polar solvent and the raw gas contact in reverse. The polar solvent absorbs a large amount of hydrogen sulfide gas, and non-polar gases such as carbon dioxide, nitrogen, and oxygen are insoluble and are directly discharged from the gas outlet in the center of the packed bed 2. After absorbing and enriching the hydrogen sulfide gas, the polar solvent continues to flow toward the outer ring of the packed bed 2, and is mixed with the desulfurizer to react to generate acidic sulfide amine salt to achieve desulfurization. After the desulfurized acidic sulfide amine salt is collected, the amine liquid can be regenerated by heating and decomposition, and the polar solvent can be separated by distillation for recycling.

[0030] The realization of this process relies on a supergravity reactor of the present invention, and the supergravity reactor is now described in conjunction with a specific embodiment.

[0031] Embodiment 1, as Figure 2As shown, a supergravity reactor comprises a container 1 provided with a liquid outlet 20 and a packing bed 2 which rotates inside the container 1. A rotating shaft 3 is installed at the bottom center of the packing bed 2. The rotating shaft 3 is driven to rotate by a motor. A first packing area 5, a separation cylinder 4, a filter cylinder 10, and a second packing area 6 are arranged in the packing bed 2. The first packing area 5 and the second packing area 6 are both annular structures. The first packing area 5, the separation cylinder 4, the filter cylinder 10, and the second packing area 6 are concentrically nested in sequence. The first packing area 5 and the middle of the container 1 are connected to each other. A feed chamber 7 is formed, a sealing plate 14 is installed at the center of the upper surface of the container 1, and the sealing plate 14 is rotatably sealed and connected with the container 1. A first liquid inlet pipe 12 and a first gas outlet pipe 13 are installed on the sealing plate 14. The first liquid inlet pipe 12 extends into the feed chamber 7 and sprays the feed chamber 7 uniformly through the liquid outlet hole. The first liquid inlet pipe 12 is connected to the polar solvent. A gap is provided between the first filling area 5 and the separation cylinder 4 to form a gas-liquid separation chamber 8. A first gas outlet cylinder 15 and a sealing cover 16 are installed on the gas-liquid separation chamber 8. The first gas outlet cylinder 15 is a cylindrical sandwich structure. The first air outlet cylinder 15 is provided with an annular air passage, and the sealing cover 16 is also an annular structure. The outer edge of the sealing cover 16 extends downward to form a slot. The sealing cover 16 is rotatably sealed and connected to the upper part of the first air outlet cylinder 15 through the slot. The sealing cover 16 is provided with an air inlet 17, which is connected to the annular air passage. The air inlet 17 is connected to the raw gas containing hydrogen sulfide. A mixing chamber 9 is formed between the second filling area 6 and the separation cylinder 4. A plurality of filter holes 11 are provided on the filter cylinder 10, and the filter holes 11 are evenly spaced and distributed on the filter cylinder 10. The outer circumferential surface of the filter cylinder 10 is arranged in close contact with the inner annular surface of the second filling area 6, and a second liquid inlet cylinder 18 is arranged in the mixing chamber 9. An annular liquid passage is arranged in the second liquid inlet cylinder 18, and the second liquid inlet cylinder 18 extends into the mixing chamber 9. A second liquid inlet port 19 is opened on the second liquid inlet cylinder 18, and the second liquid inlet port 19 is connected to the desulfurizer. A liquid passage 26 is arranged at the bottom of the mixing chamber 9 and the gas-liquid separation chamber 8. The liquid passage 26 is a circular ring structure with a U-shaped cross-section to form a communicating vessel structure to allow the liquid in the gas-liquid separation chamber 8 to enter the mixing chamber 8.

[0032] A plurality of liquid permeable holes may also be provided at the bottom of the separation tube 4 as the liquid passage 26 .

[0033] The raw gas enters the first gas outlet tube 15 through the gas inlet 17, and then enters the gas-liquid separation chamber 8. The polar solvent enters the feed chamber 7 through the first liquid inlet pipe 12. The raw gas and the polar solvent perform reverse contact mass transfer in the first packing area 5. Hydrogen sulfide is absorbed in the polar solvent. Non-polar gases such as carbon dioxide are directly discharged from the first gas outlet pipe 13. The polar solvent that absorbs hydrogen sulfide enters the gas-liquid separation chamber 8 and enters the mixing chamber 9 from the liquid passage 26. The amine liquid enters the mixing chamber 9 through the second liquid inlet 19 and the second liquid inlet tube 18. Under the action of centrifugal force, the amine liquid and the polar solvent are divided into liquid films and spread on the filter cylinder 10. Under the guidance of the filter holes 11 evenly distributed on the filter cylinder 10, they are evenly dispersed in the second packing area 6 for mass transfer reaction. Finally, they are thrown out from the packing bed 2 and discharged and collected through the liquid outlet 20.

[0034] Embodiment 2, as Figure 3 As shown, the difference between it and Example 1 is that the outer ring of the packing bed 2 is set lower than the inner ring, the second packing area 6 does not completely fill the outer ring of the entire packing bed 2, and a gap is set between it and the packing bed 2, so that the second packing area 6 can move vertically up and down in the packing bed 2, and the amine liquid and the polar solvent are not mixed but directly discharged into the mixing chamber 9, and are evenly divided by the filter cartridge 10, and the evenly divided mixing effect is poor, as shown in FIG. Figure 4 As shown, the liquid outlet end of the liquid passage 26 extends upward to form a double annular ridge 21, the inner ridge 21 and the separation cylinder 4 form an annular groove for storing amine liquid, and the second liquid inlet cylinder 18 extends to the inner ring of the ridge 21, and the liquid outlet end surface at the bottom of the second liquid inlet cylinder 18 is lower than the top surface of the ridge 21, so that the overflowing amine liquid in the annular groove and the overflowing polar solvent in the liquid passage 26 are at the same horizontal plane, and can be enhanced mixed under the drive of centrifugal force.

[0035] The packing bed 2 is provided with a driving mechanism, which includes a plurality of slide bars 22, rollers 24 matching the number of slide bars 22, a plurality of springs 25, and an adjusting plate 23. The springs 25 are arranged on the outer ring of the packing bed 2, and the springs 25 are arranged around the separation tube 4 at uniform intervals. The springs 25 are located between the bottom surface of the second packing area 6 and the packing bed 2. The springs 25 can be mounted on a fixed block for limiting and preventing sliding. The springs 25 are in a compressed state so that they can lift the second packing area 6 upward. The axis of the roller 24 is rotatably connected to the top of the slide bar 22, and the bottom end of the slide bar 22 vertically passes through the top surface of the packing bed 2 and is slidably connected to the packing bed 2. The bottom end of the slide bar 22 is fixedly connected to the second packing area 6. The adjusting plate 23 is a circular ring structure, and the adjusting plate 23 is coaxially arranged with the packing bed 2. The top end of the adjusting plate 23 is fixedly connected to the inner top surface of the container 1, such as Figure 5As shown, the bottom surface of the adjusting plate 23 is wavy, and the bottom surface of the adjusting plate 23 is vertically abutted against the roller 24. The rotation of the packing bed 2 drives the second packing area 6 to rotate. The sliding rod 22 on the second packing area 6 is squeezed by the adjusting plate 23 to push the second packing area 6 to move downward and squeeze the spring 25. When the roller 24 moves to the highest point of the wavy line of the adjusting plate 23, the spring 25 pushes the second packing area 6 to move upward. The sinking height of the second packing area 6 is adjusted to make the second packing area 6 move up and down with the convex edge 21 as the amplitude center. The amine liquid overflowing from the annular groove and the polar solvent overflowing from the liquid passage 26 are at the same horizontal plane. If it is directly sprayed on the second packing area 6, it is easy to cause local reaction overheating and waste the mixing capacity of other second packing areas 6. The second packing area 6 that reciprocates up and down can mix the reaction liquid at different heights and constantly change the height, thereby improving the heat dissipation and mixing effect.

[0036] Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments, or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A process for absorbing low-content hydrogen sulfide gas, characterized in that: A raw gas containing hydrogen sulfide is introduced into a packed bed (2) in a supergravity reactor, and a polar solvent is introduced into the middle of the supergravity reactor, so that the polar solvent and the raw gas are in reverse contact, the polar solvent absorbs a large amount of hydrogen sulfide gas, and non-polar gases such as carbon dioxide are directly discharged, and the polar solvent continues to flow toward the outer ring of the packed bed (2) and is mixed with the desulfurizer for contact reaction and desulfurization.

2. A process for absorbing low-content hydrogen sulfide gas according to claim 1, characterized in that: The polar solvent is selected from one or more of anhydrous methanol and anhydrous ethanol, and the desulfurizing agent is selected from one or more of ethanolamine and methyldiethanolamine.

3. A process for absorbing low-content hydrogen sulfide gas according to claim 1, characterized in that: The ultra-gravity reactor comprises a container (1) provided with a liquid outlet (20) and a packing bed (2) located inside the container (1) and rotating. A first packing area (5), a separation tube (4), and a second packing area (6) are arranged inside the packing bed (2). The first packing area (5) and the second packing area (6) are both annular structures. The first packing area (5), the separation tube (4), and the second packing area (6) are concentrically nested in sequence. The first packing area (5) and the middle part of the container (1) form a feed cavity (7). The feed cavity (7) is provided with a first liquid inlet. A first gas outlet pipe (13) and the first liquid inlet pipe (12) and the first gas outlet pipe (13) are connected to the feed chamber (7); a gas-liquid separation chamber (8) is provided between the first filling area (5) and the separation tube (4); a raw gas inlet is provided at the top of the gas-liquid separation chamber (8); a mixing chamber (9) is provided between the second filling area (6) and the separation tube (4); a desulfurizer inlet is provided in the mixing chamber (9); a liquid passage (26) is provided at the bottom of the mixing chamber (9) for communication with the gas-liquid separation chamber (8).

4. A process for absorbing low-content hydrogen sulfide gas according to claim 3, characterized in that: A filter cartridge (10) is arranged in the packing bed (2), a plurality of filter holes (11) are arranged on the filter cartridge (10), and the filter cartridge (10) is concentrically arranged between the separation cartridge (4) and the second packing area (6).

5. A process for absorbing low-content hydrogen sulfide gas according to claim 3, characterized in that: The liquid passage (26) is a circular ring structure with a U-shaped cross section.

6. A process for absorbing low-content hydrogen sulfide gas according to claim 5, characterized in that: The liquid outlet end of the liquid passage (26) extends upward to form a double-circular ring-shaped convex edge (21), and the desulfurizing agent inlet extends to the inner ring of the convex edge (21).

7. A process for absorbing low-content hydrogen sulfide gas according to claim 6, characterized in that: The packing bed (2) is provided with a driving mechanism, and the driving structure drives the second packing area (6) to move up and down with the convex edge (21) as the amplitude center.

8. A process for absorbing low-content hydrogen sulfide gas according to claim 7, characterized in that: The driving mechanism comprises a slide bar (22), a roller (24), a spring (25), and an adjustment plate (23); the spring (25) is located between the bottom surface of the second filling area (6) and the filling bed (2); the axis of the roller (24) is rotatably connected to the top of the slide bar (22); the bottom end of the slide bar (22) passes through the top surface of the filling bed (2) and is slidably connected to the filling bed (2); the bottom end of the slide bar (22) is fixedly connected to the second filling area (6); the adjustment plate (23) is in a circular shape; the adjustment plate (23) is coaxially arranged with the filling bed (2); the adjustment plate (23) is fixedly connected to the container (1); the bottom surface of the adjustment plate (23) is wavy; the bottom surface of the adjustment plate (23) is in contact with the roller (24).

9. A process for absorbing low-content hydrogen sulfide gas according to claim 3, characterized in that: The gas-liquid separation chamber (8) is provided with a first air outlet cylinder (15) and a sealing cover (16); an annular air passage is provided inside the first air outlet cylinder (15); the sealing cover (16) is rotatably sealed and connected to the upper part of the first air outlet cylinder (15); an air inlet (17) is provided on the sealing cover (16); and the air inlet (17) is connected to the annular air passage.

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