System for purifying hydrogen sulfide-containing gas and method for purifying hydrogen sulfide-containing gas

Abstract

The invention relates to the field of purification of hydrogen sulfide in petrochemical tail gas, and discloses a system for purifying gas containing hydrogen sulfide and a method for purifying the gas containing hydrogen sulfide. A system for purifying gas containing hydrogen sulfide comprises a reactor, the reactor comprises a membrane mixing area and a reaction area, the membrane mixing area comprises a shell and a tubular membrane assembly arranged in the shell, and an in-tube channel of the membrane assembly is used for allowing absorption liquid to pass through. The microporous channels on the tube wall of the membrane component are used for allowing hydrogen sulfide-containing gas to pass through to contact with absorption liquid; the reaction zone is used for reacting hydrogen sulfide-containing gas with the absorption liquid. The system has the advantages of simple process, good hydrogen sulfide treatment effect, low operation cost and the like.

Description

Technical Field

[0001] The invention relates to the field of purification of hydrogen sulfide in petrochemical tail gas, and in particular to a system for purifying hydrogen sulfide-containing gas and a method for purifying hydrogen sulfide-containing gas. Background Art

[0002] Refinery acid gas is a by-product of the petrochemical production process. It is characterized by large quantity, high toxicity and foul odor. It mainly comes from units such as acid water stripping, circulating hydrogen desulfurization and dry gas desulfurization. It mainly contains hydrogen sulfide and carbon dioxide, and is one of the important sources of pollution for petrochemical enterprises.

[0003] Acidic gases in large petrochemical enterprises are mainly used to prepare sulfur. There are two commonly used process technologies: one is Merichem's LO-CAT technology; the other is the two-stage Claus process + tail gas hydrogenation reduction + solvent absorption process.

[0004] For small and medium-sized petrochemical enterprises, the use of Merichem's LO-CAT technology has problems such as high catalyst and technology transfer fees and large investments; the Claus method is used to process sulfur-containing tail gas into sulfur and sell it as a product, but this method has disadvantages such as complex process flow, large investment, low output and high operating costs. At present, most small and medium-sized petrochemical enterprises basically use simple alkaline solution for simple absorption or direct discharge by torch combustion. This method has brought great pressure to environmental protection and caused huge waste of resources. For the acid gas treatment of small and medium-sized enterprises, a simple process, economical, environmentally friendly, safe and reliable acid gas treatment solution is needed.

[0005] CN219482213U discloses a device for fine desulfurization of sulfur-containing waste gas. By adopting an atomized liquid membrane bed in combination with an alkaline solution compounded with a carbonyl sulfide hydrolysis catalyst, a one-step method is used to remove hydrogen sulfide, carbonyl sulfide and mercaptans from waste gas discharged during loading and unloading of raw oil or semi-finished oil in a port tank area of ​​a petrochemical enterprise, thereby simplifying the waste gas desulfurization process. However, the catalyst cost of this method is relatively high, which is not conducive to its promotion and use in small and medium-sized petrochemical enterprises.

[0006] CN104826560A discloses a method and system for comprehensive utilization of acidic gas, which uses sodium hydroxide solution as an absorption liquid to process acidic gas to produce sodium hydrosulfide, adopts a multi-stage reactor, and the reaction liquid generated at each stage is recycled. By adding sodium hydroxide solution in stages, the reaction intensity at each stage is adjusted, and the reaction heat is peaked to prevent local crystallization caused by hot spots. This process can achieve the dual goals of acidic gas purification and pollutant resource utilization, but the process and operation of this method are complex, and the operating cost is high. Summary of the invention

[0007] The purpose of the present invention is to overcome the problems existing in the prior art and provide a system for purifying hydrogen sulfide-containing gas and a method for purifying hydrogen sulfide-containing gas. The system of the present invention has the advantages of simple process, good hydrogen sulfide treatment effect, low operating cost, etc.

[0008] In order to achieve the above-mentioned objectives, the present invention provides, on one hand, a system for purifying hydrogen sulfide-containing gas, the system comprising a reactor, the reactor comprising a membrane mixing zone and a reaction zone, the membrane mixing zone comprising a shell and a tubular membrane assembly disposed inside the shell, the in-tube channel of the membrane assembly being used for the passage of absorption liquid, the microporous channel of the tube wall of the membrane assembly being used for the passage of hydrogen sulfide-containing gas to contact with the absorption liquid; the reaction zone being used for the reaction between the hydrogen sulfide-containing gas and the absorption liquid.

[0009] Preferably, the diameter of the channel in the membrane module tube is 50-3500 μm, preferably 1000-3500 μm.

[0010] Preferably, the micropore diameter of the membrane assembly is 1-1000 nm, preferably 30-1000 nm, more preferably 30-800 nm.

[0011] Preferably, the proportion of micropores with a pore size of 50-500 nm to the total pores is not less than 95%, preferably 95-98%.

[0012] The second aspect of the present invention provides a method for purifying hydrogen sulfide-containing gas using the system described in the first aspect, the method comprising: feeding an absorption liquid into the channel inside the membrane module tube in the membrane mixing zone in the reactor, and simultaneously allowing the hydrogen sulfide-containing gas to contact with the absorption liquid through the microporous channel on the wall of the membrane module tube in the membrane mixing zone in the reactor, and then allowing the hydrogen sulfide-containing gas to react with the absorption liquid in the reaction zone.

[0013] Preferably, the hydrogen sulfide content in the gas phase product obtained by the reaction is ≯50 mg / Nm 3 .

[0014] Through the above technical solution, the beneficial effects of the present invention include:

[0015] The system provided by the present invention has the characteristics of good hydrogen sulfide treatment effect, simple process, low operating cost, stable operation and not easy to be blocked.

[0016] The system for purifying hydrogen sulfide-containing gas provided by the present invention integrates multiple processing units and creatively applies high-efficiency membrane mixing to hydrogen sulfide purification, which can greatly improve the mass transfer efficiency between the gas phase and the absorption liquid, ensure rapid reaction, and greatly improve the removal rate of hydrogen sulfide, so that the hydrogen sulfide content in the purified gas is low, which is conducive to the recycling of the purified gas; at the same time, it also simplifies the purification process, can greatly save investment and operating costs, and has great promotion and application value in small and medium-sized petrochemical enterprises. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the system for purifying hydrogen sulfide-containing gas described in Example 1 of the present invention.

[0018] Description of Reference Numerals

[0019] 1. Water washing unit; 2. First gas-liquid separation unit; 3. First coalescer;

[0020] 4. Reactor; 5. Settling zone; 6. Membrane mixing zone;

[0021] 7. Circulation pump; 8. Reaction zone; 9. Gas phase buffer zone;

[0022] 10. Second coalescer; 11. Second gas-liquid separation unit; 12. Waste liquid tank;

[0023] 13. Absorption liquid storage tank;

[0024] A, hydrogen sulfide-containing gas; B, desalted water; C, first liquid stream;

[0025] D, first gas material; E, second liquid stream; F, second gas material;

[0026] G, third gas material; H, third liquid stream; I, purified gas;

[0027] J, liquid product; K, part of the liquid product J; L, the remaining part of the liquid product J; M, absorption liquid. DETAILED DESCRIPTION

[0028] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0029] On the one hand, the present invention provides a system for purifying hydrogen sulfide-containing gas, the system comprising a reactor 4, the reactor 4 comprising a membrane mixing zone 6 and a reaction zone 8, the membrane mixing zone 6 comprising a shell and a tubular membrane assembly disposed inside the shell, the intra-tube channel of the membrane assembly is used for the passage of absorption liquid, the microporous channel of the membrane assembly tube wall is used for the hydrogen sulfide-containing gas to pass through and contact with the absorption liquid; the reaction zone 8 is used for the reaction of the hydrogen sulfide-containing gas with the absorption liquid.

[0030] It should be noted that the inner channel of the membrane module of the present invention refers to the inner cavity channel formed when the membrane module is in a tubular shape; the microporous channel of the membrane module tube wall refers to the microporous channel of the membrane module itself, where the micropores are holes with a smaller pore size than the inner channel diameter. Specifically, the hydrogen sulfide-containing gas enters the microporous channel from between the outer wall of the tubular membrane module and the inner wall of the shell.

[0031] In the present invention, the hydrogen sulfide-containing gas is first passed through the membrane mixing zone 6 in the reactor 4. Under the action of the pressure difference, the hydrogen sulfide-containing gas enters the absorption liquid in a flowing state through the microporous channels on the tube wall, which can not only obtain a good dispersion and dissolution effect of the hydrogen sulfide-containing gas, but also obtain a higher absorption efficiency.

[0032] In the present invention, the membrane mixing zone 6 can be arranged inside the reactor 4 through a flange, or can be arranged on the material inlet pipeline of the reactor 4, and the present invention has no special limitation on this.

[0033] The number of channels in the tube of the membrane assembly in the shell of the present invention can be appropriately selected according to the specific working conditions. In some preferred embodiments, the number of channels in the tube of the membrane assembly is 4-20. By adopting this preferred embodiment, the dispersion effect of the hydrogen sulfide-containing gas in the absorption liquid can be further improved, so that the hydrogen sulfide-containing gas can be dispersed and dissolved in the absorption liquid faster and more evenly.

[0034] The present invention has no particular limitation on the distance between the channels in the tubes of the membrane module, and generally they can be evenly distributed.

[0035] In some preferred embodiments, in the membrane assembly, the diameter of the channel in the tube is 50-3500 μm, preferably 1000-3500 μm, for example, it can be 50 μm, 100 μm, 150 μm, 200 μm, 300 μm, 400 μm, 500 μm, 600 μm, 700 μm, 800 μm, 900 μm, 1000 μm, 1100 μm, 1200 μm, 1300 μm, 1400 μm, 1500 μm, 1600μm, 1700μm, 1800μm, 1900μm, 2000μm, 2100μm, 2200μm, 2300μm, 2400μm, 2500μm, 2600μm, 2700μm, 2800μm, 2900μm, 3000μm, 3100μm, 3200μm, 3300μm, 3400μm, 3500μm and any value in the range formed by any two of these point values. This preferred embodiment is matched with the micropore diameter of the following membrane assembly to improve the dispersion and mixing effect of hydrogen sulfide-containing gas in the absorption liquid.

[0036] In the present invention, the diameters of the multiple channels in the tube may be the same or different, as long as they are within the above range.

[0037] In some preferred embodiments, the micropore diameter of the membrane assembly is 1-1000 nm, preferably 30-1000 nm, and more preferably 30-800 nm.

[0038] In some preferred embodiments, in the membrane assembly, the proportion of pores with a pore size of 50-500 nm to the total pores is not less than 95%, preferably 95-98%.

[0039] Preferably, the porosity of the microporous channels in the membrane assembly is 10-80%, preferably 30-50%.

[0040] The use of the membrane assembly with the above pore distribution can further improve the dispersion and mixing effect of the hydrogen sulfide-containing gas in the absorption liquid, thereby allowing the hydrogen sulfide-containing gas to be dispersed in the absorption liquid more quickly and evenly.

[0041] The present invention has no particular limitation on the type of membrane component material, which can be either inorganic or organic, as long as the pore distribution of the membrane component meets the above requirements and the membrane component material does not chemically interact with the hydrogen sulfide-containing gas and the absorption liquid. In some preferred embodiments, the membrane component is a porous ceramic membrane and / or a silicon carbide membrane.

[0042] The present invention has a wide range of selections for the types of porous ceramic membranes, which can be conventionally selected in the art, as long as the pore distribution meets the above requirements.

[0043] In some preferred embodiments, the reactor 4 is a tubular reactor, and the ratio of the length to the inner diameter of the tubular reactor is 5-100:1, preferably 8-20:1, for example, it can be 5:1, 8:1, 10:1, 15:1, 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1, 90:1, 100:1 and any value in the range formed by any two of these point values. The use of this preferred embodiment is conducive to ensuring that the hydrogen sulfide-containing gas and the absorption liquid are fully reacted and fully separated, thereby improving the purification effect.

[0044] The inner diameter of the tubular reactor of the present invention can be conventionally selected. In some preferred embodiments, the inner diameter of the tubular reactor is 10-2000mm, preferably 50-500mm, for example, it can be 10mm, 20mm, 50mm, 100mm, 150mm, 200mm, 250mm, 300mm, 350mm, 400mm, 450mm, 500mm, 600mm, 700mm, 800mm, 900mm, 1000mm, 1100mm, 1200mm, 1300mm, 1400mm, 1500mm, 1600mm, 1700mm, 1800mm, 1900mm, 2000mm and any value in the range formed by any two of these point values.

[0045] In some preferred embodiments, the reactor 4 further comprises a gas phase buffer zone 9 for separating the gas phase product from the liquid phase product in the reaction zone product. The gas phase buffer zone 9 can achieve sufficient separation of the gas phase product from the liquid phase product in the reaction zone product.

[0046] In some preferred embodiments, the reactor 4 further comprises a second coalescer 10 disposed at the top for capturing fine droplets in the gas phase product.

[0047] The specific type of the second coalescer is conventionally selected in the art. Preferably, the second coalescer 10 is a cylindrical screen. Since the pores of the cylindrical screen are finer and non-sticky, fine droplets in the gas phase product will be captured, further reducing the moisture content in the gas phase product, creating conditions for reducing the further processing cost of the purified gas.

[0048] In the present invention, some sediment may be produced during the reaction and carried out with the liquid phase product. In order to prevent membrane clogging, a settling area 5 is provided at the bottom of the reactor 4. The sediment carried by the liquid phase product circulating back to the reactor 4 can be discharged from the settling area 5 and sent to the waste liquid tank 12 for unified treatment. In some preferred embodiments, the reactor 4 further includes a settling area 5 provided at the bottom for discharging the sediment.

[0049] In some preferred embodiments, the system further comprises a circulation pump 7, one end of which is connected to the absorption liquid storage tank 13 and the outlet of the liquid product of the reaction zone of the reactor 4, and the other end is connected to the settling zone 5, for delivering the absorption liquid in the absorption liquid storage tank 13 and at least part of the liquid product of the reaction zone of the reactor 4 into the reactor 4 to absorb hydrogen sulfide. In this preferred embodiment, the absorption liquid can be circulated to the reactor 4 for reuse.

[0050] When the hydrogen sulfide treatment effect is good (the hydrogen sulfide content of the purified gas is ≯50mg / Nm 3 ), no additional absorption liquid is added, that is, the absorption liquid in the absorption liquid storage tank 13 is not introduced.

[0051] When the hydrogen sulfide treatment effect is poor (the hydrogen sulfide content of the purified gas is higher than 50mg / Nm 3 ), part of the liquid products in the reaction zone of the reactor 4 can be discharged to the waste liquid tank 12 according to the actual content of hydrogen sulfide in the purified gas, and the same volume of absorption liquid is added (the amount discharged is equal to the amount added), that is, the absorption liquid in the absorption liquid storage tank 13 is introduced at this time.

[0052] In some preferred embodiments, the system further comprises a second gas-liquid separation unit 11 for performing gas-liquid separation on the gas phase product from the reactor 4 to obtain a purified gas and a third liquid stream. At this time, the purified gas is recovered and the third liquid stream is sent to a waste liquid tank 12 for treatment.

[0053] In some preferred embodiments, the moisture content in the hydrogen sulfide-containing gas is not higher than 0.05 wt %, preferably not higher than 0.01 wt %. The moisture content in the hydrogen sulfide-containing gas entering the membrane mixing zone 6 is strictly controlled at an extremely low level, mainly to avoid clogging of the membrane mixing zone 6 or increased pressure drop.

[0054] When the moisture content in the hydrogen sulfide-containing gas is higher than 0.05wt%, the system also includes a first gas-liquid separation unit 2, and the second gas material outlet of the first gas-liquid separation unit 2 is connected to the gas inlet of the membrane mixing zone 6 in the reactor 4, which is used to perform gas-liquid separation on the hydrogen sulfide-containing gas to obtain a second liquid flow and a second gas material, wherein the water content in the second gas material is not higher than 0.05wt%.

[0055] In some preferred embodiments, a first coalescer 3 is disposed on the top of the first gas-liquid separation unit 2 to capture fine liquid droplets in the gas phase to obtain a second gas material.

[0056] The specific type of the first coalescer is conventionally selected in the art. Preferably, the first coalescer 3 is a cylindrical screen. Since the pores of the cylindrical screen are finer and non-sticky, the fine droplets in the separated second gas material will be captured, further reducing the moisture content in the second gas material, which can effectively avoid clogging of the membrane mixing hydrogen zone or increased pressure drop.

[0057] The hydrogen sulfide-containing gas described in the present invention is any hydrogen sulfide-containing gas of various compositions commonly used in the art, and may or may not contain ammonia.

[0058] When the hydrogen sulfide-containing gas to be treated contains ammonia, it is easy to react with hydrogen sulfide to form sulfur-ammonia crystals that are easily soluble in water. The precipitation of this substance is easy to cause blockage of the membrane mixing zone in the subsequent reactor or increase in pressure drop. Therefore, it is necessary to remove it first. The present invention does not specifically limit the method for removing sulfur-ammonia crystals, and conventional methods in the art can be used to remove them. In some preferred embodiments, when the hydrogen sulfide-containing gas contains ammonia, the system also includes a water washing unit 1, which is used to remove ammonia and sulfur-ammonia crystals in the hydrogen sulfide-containing gas to obtain a first gas material and a first liquid stream, wherein the water content in the first gas material is not higher than 0.05wt%. Using this preferred embodiment, the sulfur-ammonia crystals are effectively absorbed to prevent subsequent membrane mixing zones from being blocked or pressure drops from being increased. At this time, the first liquid stream obtained by the water washing unit 1 is sent to the waste liquid tank 12 for treatment.

[0059] When the moisture content of the first gas material obtained by the water washing unit 1 is higher than 0.05wt%, according to a specific embodiment of the present invention, the system also includes a water washing unit 1 and a first gas-liquid separation unit 2 connected in sequence, wherein the first gas material outlet of the water washing unit 1 is connected to the inlet of the first gas-liquid separation unit 2, and the second gas material outlet of the first gas-liquid separation unit 2 is connected to the gas inlet of the membrane mixing zone 6 in the reactor 4.

[0060] It is understood that the moisture content in the gas phase passing through the microporous channels of the membrane assembly in the membrane mixing zone 6 in the reactor 4 is not higher than 0.05wt%. When the moisture content in the gas phase passing through the microporous channels of the membrane assembly in the membrane mixing zone 6 in the reactor 4 is higher than 0.05wt%, it needs to enter the first gas-liquid separation unit 2 first.

[0061] When the hydrogen sulfide treatment effect is good (the hydrogen sulfide content in the gas phase product obtained by the reaction is ≯50mg / Nm 3 ), according to a specific embodiment of the present invention, hydrogen sulfide-containing gas A enters deionized water B from the lower part of the water washing unit 1 (below the water surface) for water washing to obtain a first gas material D and a first liquid stream C. The first gas material D enters the first gas-liquid separation unit 2 for gas-liquid separation, and passes through the first coalescer 3 (cylindrical screen) to obtain a second gas material F and a second liquid stream E. The second gas material F and the absorption liquid M from the absorption liquid storage tank 13 pass through the membrane mixing zone 6 of the reactor 4, the through-hole channel of the tubular membrane assembly is used for the absorption liquid to pass, and the microporous channel of the membrane assembly is used for the second gas material F to pass and efficiently mix with the absorption liquid M and then enter the reaction zone 8 to react to obtain a liquid product J and a gas product, and the gas product passes through the gas buffer zone 9 and the second coalescer 10 (cylindrical screen) to obtain a third gas material G, and the third gas material G enters the second gas-liquid separation unit 11 for gas-liquid separation to obtain a third liquid stream H and a purified gas I. The purified gas I is recycled.

[0062] The liquid product J is driven by the circulation pump 7 to circulate from bottom to top through the settling zone 5 in the reactor 4 to form a closed loop, and a trace amount of sediment E is precipitated in the settling zone 5. The first liquid stream C, the second liquid stream E, and the third liquid stream H are combined into the waste liquid tank 12 for treatment.

[0063] When the hydrogen sulfide treatment effect is poor (the hydrogen sulfide content in the gas phase product obtained by the reaction is higher than 50 mg / Nm 3 ), according to a specific embodiment of the present invention, as Figure 1 As shown, hydrogen sulfide-containing gas A enters deionized water B from the lower part of the water washing unit 1 (below the water surface) for water washing to obtain a first gas material D and a first liquid stream C. The first gas material D enters the first gas-liquid separation unit 2 for gas-liquid separation, passes through the first coalescer 3 (cylindrical screen), and obtains a second gas material F and a second liquid stream E. The second gas material F and the absorption liquid M from the absorption liquid storage tank 13 pass through the membrane mixing zone 6 of the reactor 4. The through-hole channel of the membrane assembly is used for the absorption liquid to pass through, and the microporous channel of the tubular membrane assembly is used for the second gas material F to pass through and efficiently mix with the absorption liquid M and then enter the reaction zone 8 for reaction to obtain a liquid product J and a gas product. The gas product passes through the gas buffer zone 9 and the second coalescer 10 (cylindrical screen) to obtain a third gas material G. The third gas material G enters the second gas-liquid separation unit 11 for gas-liquid separation to obtain a third liquid stream H and a purified gas I. The purified gas I is recycled.

[0064] Part of the material K of the liquid product J is discharged to the waste liquid tank 12, and the remaining part of the material L of the liquid product J is mixed with the absorption liquid M (with the same mass as the part of the material K of the liquid product J) from the absorption liquid storage tank 13, and then enters the reactor from bottom to top through the sedimentation zone 5 in the reactor 4 under the push of the circulation pump 7 to form a closed loop, and a trace amount of sediment E is precipitated in the sedimentation zone 5. The first liquid stream C, the second liquid stream E, and the third liquid stream H are combined into the waste liquid tank 12 for treatment.

[0065] The second aspect of the present invention provides a method for purifying hydrogen sulfide-containing gas using the system described in the first aspect, the method comprising: feeding an absorption liquid into the channel inside the membrane module tube in the membrane mixing zone in the reactor, and simultaneously allowing the hydrogen sulfide-containing gas to contact with the absorption liquid through the microporous channel on the wall of the membrane module tube in the membrane mixing zone in the reactor, and then allowing the hydrogen sulfide-containing gas to react with the absorption liquid in the reaction zone.

[0066] The method of the present invention has a good effect in removing hydrogen sulfide. In some preferred embodiments, the hydrogen sulfide content in the gas phase product obtained by the reaction is ≯50 mg / Nm 3 .

[0067] The present invention has no particular limitation on the reaction conditions, and the above-mentioned hydrogen sulfide content can be reduced to the above-mentioned level.

[0068] In some preferred embodiments, the reaction temperature is 30-90°C, preferably 50-80°C.

[0069] In some preferred embodiments, the residence time of the reaction is 10-700 seconds, preferably 20-500 seconds, for example, it can be 10 seconds, 20 seconds, 30 seconds, 40 seconds, 50 seconds, 60 seconds, 70 seconds, 80 seconds, 90 seconds, 100 seconds, 150 seconds, 200 seconds, 250 seconds, 300 seconds, 350 seconds, 400 seconds, 450 seconds, 500 seconds, 550 seconds, 600 seconds, 650 seconds, 700 seconds and any value in the range formed by any two of these point values.

[0070] In some preferred embodiments, the ratio of the volume flow rate of the hydrogen sulfide-containing gas to the volume flow rate of the absorption liquid is 1-2000:1, preferably 5-1000:1, for example, it can be 1:1, 5:1, 50:1, 100:1, 150:1, 200:1, 300:1, 400:1, 500:1, 600:1, 700:1, 800:1, 900:1, 1000:1, 1100:1, 1200:1, 1300:1, 1400:1, 1500:1, 1600:1, 1700:1, 1800:1, 1900:1, 2000:1 and any value in the range formed by any two of these point values.

[0071] The specific volume flow rate of the gas phase described in the present invention can be appropriately selected according to actual conditions.

[0072] In some preferred embodiments, the mass concentration of the absorption liquid is 22-60%, preferably 28-42%.

[0073] The present invention has a wide range of choices for the type of the absorption liquid, which can be a conventional choice in the art. Preferably, the absorption liquid is an alkaline solution, preferably a sodium hydroxide aqueous solution.

[0074] In order to better achieve mixing in the membrane mixing zone and reaction in the reaction zone, in some preferred embodiments, the absorption liquid and the hydrogen sulfide-containing gas flow in the same direction, preferably from bottom to top.

[0075] Preferably, the moisture content in the hydrogen sulfide-containing gas is not higher than 0.05 wt%, preferably not higher than 0.01 wt%.

[0076] Preferably, when the water content in the hydrogen sulfide-containing gas is greater than 0.05wt%, the method further includes: performing gas-liquid separation on the hydrogen sulfide-containing gas to obtain a second gas material and a second liquid flow, contacting the second gas material with the absorption liquid through the microporous channels of the membrane assembly in the membrane mixing zone in the reactor, and then reacting the second gas material with the absorption liquid in the reaction zone, wherein the water content in the second gas material is not higher than 0.05wt%.

[0077] When the hydrogen sulfide-containing gas contains ammonia, the method also includes: washing the hydrogen sulfide-containing gas with water to obtain a first gas material and a first liquid flow, contacting the first gas material with an absorption liquid through the microporous channels of the membrane assembly in the membrane mixing zone in the reactor, and then reacting the first gas material with the absorption liquid in the reaction zone, wherein the moisture content in the first gas material is not higher than 0.05wt%.

[0078] It is understood that the water content in the gas phase passing through the microporous channels of the membrane assembly in the membrane mixing zone in the reactor is not higher than 0.05wt%. When the water content in the gas phase passing through the microporous channels of the membrane assembly in the membrane mixing zone in the reactor is higher than 0.05wt%, gas-liquid separation is required first.

[0079] The hydrogen sulfide-containing gas of the present invention can be any hydrogen sulfide-containing gas of various compositions conventionally obtained in the art. In some preferred embodiments, the hydrogen sulfide-containing gas comprises hydrogen sulfide and optionally ammonia, as well as hydrogen and / or hydrocarbons.

[0080] The method of the present invention is suitable for treating hydrogen sulfide-containing gas containing different concentrations of hydrogen sulfide. In some preferred embodiments, the volume content of hydrogen sulfide in the hydrogen sulfide-containing gas is not higher than 25%, for example, it can be 25%, 24%, 23%, 22%, 21%, 20%, 19%, 18%, 17%, 16%, 15%, 14%, 13%, 12%, 11%, 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1% and any value in the range formed by any two of these point values.

[0081] In the present invention, the "first", "second" and "third" do not limit the substances and operations, but are only used to distinguish the substances introduced in different steps and the operations performed in different stages.

[0082] The present invention will be described in detail below through examples.

[0083] The following embodiments all use tail hydrogen from a catalytic oil slurry liquid phase hydrogenation unit as the raw gas to be processed, and the specific composition is: hydrogen gas volume fraction of about 91.7%, hydrogen sulfide volume fraction of about 3.2%, hydrocarbon volume fraction of about 5.1%, and the balance is ammonia.

[0084] Example 1

[0085] Use Figure 1 The device shown.

[0086] Membrane mixing zone 6: Each membrane assembly has 19 evenly distributed in-tube channels, and the diameter of the in-tube channels is 2500μm; the micropore diameter of the membrane assembly is 1-1000nm; in the membrane assembly, the number of pores with a micropore diameter of 50-500nm accounts for about 96% of the total number of pores, and the porosity of the micropore channels of the membrane assembly is 45%; the membrane assembly is a porous ceramic membrane (purchased from Beijing Zhongtianyuan Environmental Engineering Co., Ltd.); the membrane mixing zone is arranged in the reactor 4 through a flange.

[0087] Reactor 4 is a tubular reactor, and the ratio of the length to the inner diameter of the tubular reactor is 16:1; the inner diameter of the tubular reactor is 200 mm.

[0088] The flow direction of the absorption liquid and the second gas material is from bottom to top through the membrane mixing zone 6, the inner channel of the membrane module is used for the absorption liquid to pass through, and the microporous channel of the tube wall of the tubular membrane module is used for the second gas material (water content is less than 0.01wt%) to pass through and efficiently mix with the absorption liquid and then enter the reaction zone 8 to react. Reaction conditions: reaction temperature is 60°C, the residence time of the reaction material in the reaction zone is 60 seconds, the volume flow ratio of the second gas material to the absorption liquid is 200:1, and the absorption liquid is a sodium hydroxide aqueous solution with a mass concentration of 32%.

[0089] Example 2

[0090] Use Figure 1 The device shown.

[0091] Membrane mixing zone 6: Each membrane assembly has 10 evenly distributed in-tube channels, and the diameter of the in-tube channels is 3500μm; the micropore diameter of the membrane assembly is 20-1000nm; in the membrane assembly, the number of pores with a micropore diameter of 50-500nm accounts for about 95% of the total number of pores, and the porosity of the micropore channels of the membrane assembly is 30%; the membrane assembly is a porous ceramic membrane (purchased from Beijing Zhongtianyuan Environmental Engineering Co., Ltd.); the membrane mixing zone is arranged in the reactor 4 through a flange.

[0092] Reactor 4 is a tubular reactor, the ratio of the length to the inner diameter of the tubular reactor is 16:1; the inner diameter of the tubular reactor is 200 mm.

[0093] The flow direction of the absorption liquid and the second gas material is from bottom to top through the membrane mixing zone 6, the inner channel of the membrane module is used for the absorption liquid to pass through, and the microporous channel of the tube wall of the tubular membrane module is used for the second gas material (water content is less than 0.01wt%) to pass through and efficiently mix with the absorption liquid and then enter the reaction zone 8 to react. Reaction conditions: reaction temperature is 80°C, the residence time of the reaction material in the reaction zone is 48 seconds, the volume flow ratio of the second gas material to the absorption liquid is 250:1, and the absorption liquid is a sodium hydroxide aqueous solution with a mass concentration of 32%.

[0094] Example 3

[0095] The method of Example 1 is followed, except that the water washing unit 1 is not provided.

[0096] Example 4

[0097] The method of Example 1 is followed, except that the first gas-liquid separation unit 2 is not provided.

[0098] Example 5

[0099] The method of Example 1 is followed, except that

[0100] Tubular membrane assembly; the micropore diameter of the membrane assembly is 1-1000nm; in the membrane assembly, the number of pores with a micropore diameter of 500-800nm ​​accounts for about 90% of the total number of pores, and the porosity of the micropore area is 52%.

[0101] Comparative Example 1

[0102] The method of Example 1 is followed, except that the membrane mixing zone 6 is not provided in the reactor 4, and a gas distribution plate (thickness 250 mm) with a pore size of 0.5 mm is used instead of the membrane mixer.

[0103] Table 1

[0104] Example No. <![CDATA[The hydrogen sulfide content in the purified gas, mg / Nm 3 > Device operation cycle, h Example 1 38 ＞1000h Example 2 45 ＞1000h Example 3 43 450h Example 4 43 300h Example 5 326 ＞1000h Comparative Example 1 ＞1000 --

[0105] It can be seen from the results in Table 1 that the system of the present invention has a significantly better hydrogen sulfide removal effect when purifying hydrogen sulfide, and the hydrogen sulfide content in the purified gas is lower, which is conducive to the recycling of the purified gas. At the same time, the system of the present invention is stable in operation and not easy to be blocked, which can greatly save investment and operation costs, and has great promotion and application value in small and medium-sized petrochemical enterprises.

[0106] The preferred embodiments of the present invention are described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various technical features in any other suitable manner, and these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A system for purifying hydrogen sulfide-containing gas, It is characterized in that The system comprises a reactor (4), wherein the reactor (4) comprises a membrane mixing zone (6) and a reaction zone (8), wherein the membrane mixing zone (6) comprises a shell and a tubular membrane assembly disposed inside the shell, wherein the inner channel of the membrane assembly is used for the passage of absorption liquid, and the microporous channel of the membrane assembly tube wall is used for the passage of hydrogen sulfide gas to contact with the absorption liquid; and the reaction zone (8) is used for the reaction of hydrogen sulfide gas with the absorption liquid.

2. The system according to claim 1, in, The number of channels in the membrane module tube is 4-20; Preferably, in the membrane assembly, the diameter of the channel in the tube is 50-3500 μm, preferably 1000-3500 μm.

3. The system according to claim 1 or 2, in, The micropore diameter of the membrane assembly is 1-1000 nm, preferably 30-1000 nm, more preferably 30-800 nm; Preferably, in the membrane assembly, the proportion of pores with a pore size of 50-500 nm to the total pores is not less than 95%, preferably 95-98%; Preferably, the porosity of the microporous channels of the membrane assembly is 20-80%, preferably 30-50%; Preferably, the membrane assembly is a porous ceramic membrane and / or a silicon carbide membrane.

4. A system according to any one of claims 1 to 3, in, The reactor (4) is a tubular reactor, and the ratio of the length to the inner diameter of the tubular reactor is 5-100:1, preferably 8-20:1; Preferably, the inner diameter of the tubular reactor is 10-2000 mm, preferably 50-500 mm.

5. The system according to any one of claims 1 to 4, in, The reactor (4) further comprises a gas phase buffer zone (9) for separating gas phase products from liquid phase products in the reaction zone products; Preferably, the reactor (4) further comprises a second coalescer (10) disposed at the top, for capturing fine droplets in the gas phase product; Preferably, the reactor (4) further comprises a settling zone (5) arranged at the bottom for discharging sediment.

6. The system according to any one of claims 1 to 5, in, The moisture content of the hydrogen sulfide-containing gas is not higher than 0.05wt%, preferably not higher than 0.01wt%; When the water content in the hydrogen sulfide-containing gas is higher than 0.05 wt%, the system further comprises a first gas-liquid separation unit (2), wherein the second gas material outlet of the first gas-liquid separation unit 2 is connected to the gas inlet of the membrane mixing zone 6 in the reactor 4, and is used to perform gas-liquid separation on the hydrogen sulfide-containing gas to obtain a second gas material and a second liquid stream, wherein the water content in the second gas material is not higher than 0.05 wt%; Preferably, a first coalescer (3) is provided on the top of the first gas-liquid separation unit (2) for capturing fine liquid droplets in the gas phase to obtain a second gas material; When the hydrogen sulfide-containing gas contains ammonia, the system further comprises a water washing unit (1) for removing ammonia and ammonia-sulfur crystals in the hydrogen sulfide-containing gas to obtain a first gas material and a first liquid flow, wherein the water content in the first gas material is not higher than 0.05 wt%.

7. A method for purifying hydrogen sulfide-containing gas using the system according to any one of claims 1 to 6, wherein the method include: The absorption liquid is fed into the channel inside the membrane module tube in the membrane mixing zone of the reactor, and at the same time, the hydrogen sulfide-containing gas contacts the absorption liquid through the microporous channel on the membrane module tube wall in the membrane mixing zone of the reactor, and then the hydrogen sulfide-containing gas reacts with the absorption liquid in the reaction zone.

8. The method according to claim 7, in, The hydrogen sulfide content in the gas phase product obtained by the reaction is ≯50mg / Nm 3 ; Preferably, the reaction temperature is 30-90°C, preferably 50-80°C; Preferably, the residence time of the reaction is 10-700 seconds, preferably 20-500 seconds; Preferably, the ratio of the volume flow rate of the hydrogen sulfide-containing gas to the volume flow rate of the absorption liquid is 1-2000:1, preferably 5-1000:1; Preferably, the mass concentration of the absorption liquid is 22-60%, preferably 28-42%; Preferably, the absorption liquid is an alkaline solution, preferably an aqueous sodium hydroxide solution; Preferably, the absorption liquid and the hydrogen sulfide-containing gas flow in the same direction, preferably from bottom to top.

9. The method according to claim 7, in, The moisture content of the hydrogen sulfide-containing gas is not higher than 0.05wt%; Preferably, when the water content in the hydrogen sulfide-containing gas is greater than 0.05wt%, the method further comprises: performing gas-liquid separation on the hydrogen sulfide-containing gas to obtain a second gas material and a second liquid stream, contacting the second gas material with an absorption liquid through the microporous channels of the membrane module tube wall in the membrane mixing zone in the reactor, and then reacting the second gas material with the absorption liquid in the reaction zone, wherein the water content in the second gas material is not higher than 0.05wt%; When the hydrogen sulfide-containing gas contains ammonia, the method further includes: washing the hydrogen sulfide-containing gas with water to obtain a first gas material and a first liquid flow, contacting the first gas material with an absorption liquid through the microporous channels of the membrane component tube wall in the membrane mixing zone in the reactor, and then reacting the first gas material with the absorption liquid in the reaction zone, wherein the moisture content in the first gas material is not higher than 0.05wt%.

10. The method according to any one of claims 7 to 9, in, The hydrogen sulfide-containing gas comprises hydrogen sulfide and optionally ammonia, as well as hydrogen and / or hydrocarbons; Preferably, the volume content of hydrogen sulfide in the hydrogen sulfide-containing gas is not higher than 25%.

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