Desulfurization method with low energy consumption

Abstract

The invention relates to the technical field of gas purification, and discloses a low-energy-consumption desulfurization method which comprises the following steps: (1) contacting acidic gas with foaming liquid in a microbubble generator to generate microbubbles, so as to obtain a gas-liquid mixture; wherein the foaming liquid comprises ultrafine particles and a complex iron desulfurization liquid I, and the particle size of the ultrafine particles is 10-100 microns; (2) performing reverse contact on the mixture and the complexing iron desulfurization liquid II in an absorption tower, and performing oxidation-reduction reaction to obtain purified gas and desulfurization rich liquid; (3) carrying out oxidation regeneration on the desulfurized rich solution and air in an oxidation regeneration tank to obtain regenerated gas, regenerated barren solution and regenerated sulfur slurry; (4) separating the regenerated sulfur slurry in a separator to obtain sulfur and filtrate; and returning the regenerated barren liquor and / or filtrate to the absorption tower for recycling. According to the low-energy-consumption desulfurization method provided by the invention, the bubble effect of the microbubble generator can be improved, the impact energy consumption of the microbubble generator can be reduced, the mass transfer efficiency of the absorption tower can be improved, and the desulfurization energy consumption can be reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of gas purification, and in particular relates to a low-energy consumption desulfurization method. Background Art

[0002] The complex iron desulfurization technology is a method of removing hydrogen sulfide by wet oxidation using complex iron as a catalyst. The desulfurizer containing complex iron comes into contact with the acidic gas containing hydrogen sulfide. Under the action of iron ions, the oxygen in the air is used to oxidize the hydrogen sulfide into elemental sulfur, such as the LO-CAT process and the SulFerox process.

[0003] This method is a new desulfurization technology with simple process, high working sulfur capacity and environmental protection and non-toxicity. It overcomes the disadvantages of traditional desulfurization process such as low sulfur capacity, complex desulfurization process, high secondary salt generation rate and serious environmental pollution. The sulfur dioxide content of flue gas after incineration of the purified tail gas is reduced to 20mg / Nm 3 , which can meet the ever-increasing environmental protection indicators.

[0004] The desulfurization effect of this method is closely related to the mixing effect of the desulfurizer and the acid gas. The gas-liquid mixing generally has the defect of low mass transfer efficiency. Process intensification technology can obtain a certain amount of micron-scale bubbles through mechanical crushing, fluid impact, ultrasound and other means, which helps to increase the mass transfer area and total mass transfer rate between gas and liquid, thereby greatly improving the gas-liquid mixing effect.

[0005] One of the process intensification technologies is to use a microbubble generator. However, the microbubble generator needs to consume a certain amount of energy to make the gas and liquid phases collide at high speed to generate bubbles. The microbubble generator generally has the disadvantages of high outlet pressure of the circulation pump, high energy consumption, and large pressure loss of the reaction liquid and raw gas.

[0006] Therefore, there is an urgent need to provide a low-energy desulfurization method that can improve mass transfer efficiency and desulfurization effect. Summary of the invention

[0007] The purpose of the present invention is to overcome the problems of low mass transfer efficiency, large reactor volume and high energy consumption of impinging flow microbubble generator in the prior art complex iron desulfurization technology, and to provide a low-energy desulfurization method.

[0008] In order to achieve the above object, the present invention provides a low energy consumption desulfurization method, wherein the method comprises the following steps:

[0009] (1) contacting an acidic gas and a foaming liquid in a microbubble generator to generate microbubbles to obtain a gas-liquid mixture; wherein the foaming liquid comprises ultrafine particles and a complex iron desulfurization liquid I, and the particle size of the ultrafine particles is 10-100 μm;

[0010] (2) the mixture and the complex iron desulfurization liquid II are reversely contacted in an absorption tower to cause an oxidation-reduction reaction to obtain purified gas and desulfurized rich liquid;

[0011] (3) subjecting the desulfurized rich liquid to oxidation regeneration with air in an oxidation regeneration tank to obtain regenerated gas, regenerated lean liquid and regenerated sulfur slurry;

[0012] (4) Separating the regenerated sulfur slurry in a separator to obtain sulfur and filtrate; wherein the regenerated lean liquid and / or filtrate is returned to the absorption tower for recycling.

[0013] Through the above technical solution, the beneficial technical effects achieved by the present invention are as follows:

[0014] 1) The low-energy desulfurization method provided in the present invention can use ultrafine particles to change the surface tension of the solution to form stable bubbles, which can not only reduce the outlet pressure of the circulation pump and reduce the impact energy consumption of the microbubble generator, but also significantly improve the foaming effect of the microbubble generator, increase the mass transfer area in the absorption tower, improve the mass transfer efficiency, improve the absorption effect, and realize the recovery of sulfur resources;

[0015] 2) The low-energy desulfurization method provided in the present invention has a small pressure difference between the gas-liquid mixture and the complex iron desulfurization liquid II, and a small countercurrent contact resistance, which can reduce the operating energy consumption of the absorption tower;

[0016] 3) The low-energy desulfurization method provided in the present invention can significantly reduce the volume of the equipment, reduce the floor space, and reduce the production cost by arranging the microbubble generator in the absorption tower;

[0017] 4) The low-energy desulfurization method provided in the present invention has a small equipment footprint, low energy consumption, high desulfurization efficiency, is suitable for industrial promotion, and can be used in the removal of hydrogen sulfide and sulfur recovery processes in coal gas, natural gas and refinery gas. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a process flow chart of the low energy consumption desulfurization method provided by the present invention.

[0019] Description of Reference Numerals

[0020] 1. Absorption tower 2. Micro bubble generator 3. Rich liquid pump

[0021] 4. Oxidation regeneration tank 5. Slurry pump 6. Filter

[0022] 7. Liquid replenishment pump 8. Feed pump

[0023] 21. Bubble generator 22. Circulation pump DETAILED DESCRIPTION

[0024] 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.

[0025] The present invention provides a low-energy consumption desulfurization method, wherein the method comprises the following steps:

[0026] (1) contacting an acidic gas and a foaming liquid in a microbubble generator to generate microbubbles to obtain a gas-liquid mixture; wherein the foaming liquid comprises ultrafine particles and a complex iron desulfurization liquid I, and the particle size of the ultrafine particles is 10-100 μm;

[0027] (2) the mixture and the complex iron desulfurization liquid II are reversely contacted in an absorption tower to cause an oxidation-reduction reaction to obtain purified gas and desulfurized rich liquid;

[0028] (3) subjecting the desulfurized rich liquid to oxidation regeneration with air in an oxidation regeneration tank to obtain regenerated gas, regenerated lean liquid and regenerated sulfur slurry;

[0029] (4) Separating the regenerated sulfur slurry in a separator to obtain sulfur and filtrate; wherein the regenerated lean liquid and / or filtrate is returned to the absorption tower for recycling.

[0030] In step (1):

[0031] In some embodiments of the present invention, the acidic gas is a gas containing hydrogen sulfide, wherein the content of the hydrogen sulfide is 1-30 g / Nm 3 , preferably 5-10g / Nm 3 .

[0032] In some embodiments of the present invention, the particle size of the ultrafine particles can be 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100 μm, and any number between these values, preferably 20-60 μm.

[0033] Among them, in the present invention, if the particle size of ultrafine particles is too large, the bubbles generated are easy to merge into large bubbles that are easy to break; if the particle size of ultrafine particles is too small, the liquid viscosity of the gas-liquid mixture increases, which easily leads to bubbling and liquid in the absorption tower. When the particle size of ultrafine particles is between 20-60μm, the desulfurization effect is best.

[0034] In some embodiments of the present invention, the ultrafine particles are sulfur and / or ferrous sulfide, preferably sulfur.

[0035] Among them, in the present invention, the added sulfur can be separated out through a separator together with the sulfur generated during the regeneration process, and the ferrous sulfide can be oxidized into iron ions during the regeneration process, which will not have an adverse effect on the complex iron desulfurization liquid.

[0036] In some embodiments of the present invention, the complex iron desulfurization liquid I is the complex iron desulfurization liquid disclosed in CN1168526C (complex iron method for removing sulfides from gas) or CN1354038A (improved complex iron method for removing sulfides from gas).

[0037] The present invention does not specifically limit the complex iron desulfurization liquid I, and any complex iron desulfurization liquid known in the art can be used in the present invention, for example, the complex iron desulfurization liquid disclosed in CN1168526C or CN1354038A can be used.

[0038] In some embodiments of the present invention, in the foaming liquid, the content of the ultrafine particles is 1-6 g / L, preferably 2.5-4 g / L.

[0039] Among them, in the present invention, if the content of ultrafine particles is too much, the gas content in the gas-liquid mixture is too high, which easily leads to foaming and liquid carrying in the absorption tower; if the content of ultrafine particles is too little, the mass transfer efficiency of the absorption tower is low and the desulfurization effect is poor. When the content of ultrafine particles is preferably between 2.5-4g / L, the best mass transfer efficiency and the best desulfurization effect can be obtained under the premise of avoiding liquid carrying in the absorption tower.

[0040] In some embodiments of the present invention, the acid gas and the foaming liquid are used in a ratio of 1Nm 3 : 1-3.5L, preferably 1Nm 3 : 1.5-2.5L.

[0041] In some embodiments of the present invention, the contact time between the acid gas and the foaming liquid is 5-30 s, preferably 15-25 s.

[0042] In some embodiments of the present invention, the microbubble generator includes a bubble generator and a circulation pump; wherein the bubble generator is arranged inside the absorption tower and located at the lower end of the absorption tower; and the circulation pump is arranged outside the absorption tower.

[0043] Among them, in the present invention, the bubble generator of the microbubble generator can be arranged outside the absorption tower, and can also be arranged inside the absorption tower, preferably arranged inside the absorption tower. The bubble generator of the microbubble generator is arranged in the absorption tower and arranged at the lower end of the absorption tower, which can significantly reduce the volume of the equipment, reduce the floor space, and reduce the production cost.

[0044] In some embodiments of the present invention, the circulation flow rate of the circulation pump is 5-15 L / h, preferably 8-12 L / h.

[0045] Among them, in the present invention, by controlling the addition amount of ultrafine particles and / or the circulation flow rate of the circulation pump, the foaming effect of the microbubble generator can be adjusted to maximize the desulfurization effect while avoiding liquid from the absorption tower.

[0046] In some embodiments of the present invention, the outlet pressure of the circulation pump is 50-150 kPa, preferably 80-120 kPa.

[0047] Among them, in the present invention, by adding ultrafine particles, not only can the outlet pressure of the circulation pump in the microbubble generator be significantly reduced, so that the microbubble generator can achieve good foaming effect at a lower pressure, but also the pressure difference between the gas-liquid mixture and the absorption tower can be reduced, thereby reducing resistance as much as possible and further reducing energy desulfurization consumption.

[0048] In step (2):

[0049] In some embodiments of the present invention, the complex iron desulfurization liquid II is the same as the complex iron desulfurization liquid I.

[0050] Among them, in the present invention, the complex iron desulfurization liquid is divided into two parts, which are marked as complex iron desulfurization liquid I and complex iron desulfurization liquid II for the convenience of description. Complex iron desulfurization liquid I is used to mix with ultrafine particles to form a foaming liquid so as to bring the ultrafine particles from the pipeline of the circulation pump into the microbubble generator. Complex iron desulfurization liquid II is sprayed from the top of the absorption tower and countercurrently contacts with the mixture from the microbubble generator to absorb hydrogen sulfide.

[0051] In some embodiments of the present invention, based on 1Nm 3 The acidic gas is removed, and the dosage of the complex iron desulfurization liquid II is 10-30L, preferably 15-25L.

[0052] In some embodiments of the present invention, the operating conditions of the absorption tower include: absorption temperature of 30-50°C, preferably 40-45°C, and absorption pressure of 10-80 kPa, preferably 20-50 kPa.

[0053] Among them, in the present invention, the bubbling liquid is first introduced into the microbubble generator to contact with the acidic gas, and then countercurrently contacted with the complex iron desulfurization liquid II, which can greatly improve the mass transfer efficiency of the absorption tower and significantly improve the desulfurization effect of hydrogen sulfide, so that the content of hydrogen sulfide in the purified gas is ≤20mg / Nm 3 For example, the content of hydrogen sulfide in the purified gas can be 0-20 mg / Nm 3 .

[0054] In step (3):

[0055] In some embodiments of the present invention, based on 1Nm 3 The acidic gas is used in an amount ratio of 100-250L, preferably 150-200L.

[0056] In some embodiments of the present invention, the operating conditions of the regeneration tower include: a regeneration temperature of 30-50°C, preferably 40-45°C; a regeneration pressure of 2-10 kPa, preferably 4-6 kPa.

[0057] In step (4):

[0058] In some embodiments of the present invention, the separator comprises a filter and / or a centrifuge, preferably a filter.

[0059] In the present invention, the ultrafine particles introduced by the foaming liquid can be used as sulfur generated in the sulfur nucleus enrichment regeneration process, and the sulfur generated in the regeneration process is adsorbed on the surface of the ultrafine particles, which helps to improve the separation effect of sulfur in the regenerated sulfur slurry. The obtained filtrate can be mixed with the regenerated lean liquid and returned to the absorption tower for recycling, or used to prepare the foaming liquid.

[0060] The present invention will be described in detail below through examples.

[0061] Examples and Comparative Examples Figure 1 The process flow of the low-energy desulfurization method shown is as follows: wherein the microbubble generator 2 includes a bubble generator 21 and a circulation pump 22, the bubble generator is arranged inside the absorption tower and in the tower kettle of the absorption tower, the circulation pump is arranged outside the absorption tower, and the volume of the bubble generator is 5.8L;

[0062] The bottom of the absorption tower 1 is connected to the rich liquid pump 3, the oxidation regeneration tank 4, the slurry pump 5, and the filter 6 in sequence. The filter 6 is connected to the top of the absorption tower 1 through the replenishment pump 7, the oxidation regeneration tank 4, and the feed pump 8 in sequence.

[0063] Acid gas: H 2 The content of S is 6.2g / Nm 3 , CO 2 The content is 5% (v / v), and the balance gas is nitrogen.

[0064] Example 1

[0065] (1) Acid gas at 1.2Nm 3 / h enters the microbubble generator, the bubbling liquid enters the microbubble generator through the self-circulation pipeline of the microbubble generator at a flow rate of 2.5L / h, the acidic gas and the bubble liquid contact in the microbubble generator for 21s to generate microbubbles to obtain a gas-liquid mixture; wherein the bubbling liquid is a complex iron desulfurization liquid containing sulfur, the average particle size of the sulfur is 20μm, and the mass content is 3.2g / L; the outlet pressure of the circulation pump is 100kPa, and the circulation flow rate is 10L / h;

[0066] (2) The gas-liquid mixture leaves the microbubble generator and enters the absorption tower, where it contacts the complex iron desulfurization liquid injected from the top of the absorption tower at a flow rate of 20 L / h in reverse direction, undergoes an oxidation-reduction reaction at 40°C and 40 kPa, and obtains purified gas and desulfurized rich liquid;

[0067] (3) The desulfurized rich liquid is discharged from the bottom of the absorption tower and then enters the oxidation regeneration tank, where it contacts the air entering the regeneration tower at a flow rate of 180 L / h and undergoes oxidation regeneration reaction at 42°C and 4 kPa to obtain regenerated gas, regenerated lean liquid and regenerated sulfur slurry;

[0068] (4) The regenerated sulfur slurry is first introduced into a filter for filtration to obtain sulfur and filtrate; the obtained filtrate is returned to the regeneration oxidation tank and returned to the absorption tower together with the regeneration lean liquid for recycling.

[0069] After 48 hours of operation, the gas content of the gas-liquid mixture leaving the microbubble generator was measured by a conductivity probe to be 37.9%, and the hydrogen sulfide content of the purified gas extracted from the top of the absorption tower was 5 mg / Nm 3 .

[0070] Example 2

[0071] The same as Example 1, except that the average particle size of sulfur in the foaming liquid is 60 μm, and the mass content is 2.5 g / L; the foaming liquid enters the microbubble generator through the self-circulation pipeline of the microbubble generator at a flow rate of 1.8 L / h, and the contact time between the acidic gas and the foaming liquid is 25 s; the outlet pressure of the circulation pump is 120 kPa, and the circulation flow rate is 8 L / h.

[0072] After 48 hours of operation, the gas content of the gas-liquid mixture leaving the microbubble generator was measured by a conductivity probe to be 36.4%, and the hydrogen sulfide content of the purified gas extracted from the top of the absorption tower was 7 mg / Nm 3 .

[0073] Example 3

[0074] The same as Example 1, except that the average particle size of sulfur in the foaming liquid is 40 μm, the mass content is 4.0 g / L, the foaming liquid enters the microbubble generator through the self-circulation pipeline of the microbubble generator at a flow rate of 3.0 L / h, the contact time between the acidic gas and the foaming liquid is 15 s; the outlet pressure of the circulation pump is 80 kPa, and the circulation flow rate is 12 L / h.

[0075] After 48 hours of operation, the gas content of the gas-liquid mixture leaving the microbubble generator was measured by a conductivity probe to be 34.7%, and the hydrogen sulfide content of the purified gas extracted from the top of the absorption tower was 10 mg / Nm 3 .

[0076] Example 4

[0077] The same as Example 1, except that the foaming liquid is a complex iron desulfurization liquid containing ferrous sulfide, the average particle size of ferrous sulfide is 10 μm, and the mass content is 5 g / L; the foaming liquid enters the microbubble generator through the self-circulation pipeline of the microbubble generator at a flow rate of 1.2 L / h, and the contact time between the acidic gas and the foaming liquid is 10 s; the outlet pressure of the circulation pump is 150 kPa, and the circulation flow rate is 15 L / h.

[0078] After 48 hours of operation, the gas content of the gas-liquid mixture leaving the microbubble generator was measured by a conductivity probe to be 33.1%, and the hydrogen sulfide content of the purified gas extracted from the top of the absorption tower was 15 mg / Nm 3 .

[0079] Example 5

[0080] The same as Example 1, except that the average particle size of sulfur in the foaming liquid is 80 μm, the mass content is 1.5 g / L, the foaming liquid enters the microbubble generator through the self-circulation pipeline of the microbubble generator at a flow rate of 3.6 L / h, the contact time between the acidic gas and the foaming liquid is 30 s; the outlet pressure of the circulation pump is 70 kPa, and the circulation flow rate is 5 L / h.

[0081] After 48 hours of operation, the gas content of the gas-liquid mixture leaving the microbubble generator was measured by a conductivity probe to be 31.7%, and the hydrogen sulfide content of the purified gas extracted from the top of the absorption tower was 19 mg / Nm 3 .

[0082] Comparative Example 1

[0083] The same as Example 4, except that the foaming liquid is omitted.

[0084] After 48 hours of operation, the gas content of the gas-liquid mixture leaving the microbubble generator was measured by a conductivity probe to be 16%, and the hydrogen sulfide content of the purified gas extracted from the top of the absorption tower was 78 mg / Nm 3 .

[0085] Among them, by comparing Example 4 and Comparative Example 1, it can be seen that the foaming effect of the microbubble generator is poor when the outlet pressure of the circulation pump is low.

[0086] Comparative Example 2

[0087] The same as Example 4, except that the bubbling liquid is omitted and the outlet pressure of the circulation pump is 300 kPa.

[0088] After 48 hours of operation, the gas content of the gas-liquid mixture leaving the microbubble generator was measured by a conductivity probe to be 33.4%, and the hydrogen sulfide content of the purified gas extracted from the top of the absorption tower was 15 mg / Nm 3 .

[0089] Among them, by comparing Example 4 with Comparative Example 2, it can be seen that adding ultrafine particles to the microbubble generator can enable the microbubble generator to achieve a foaming effect similar to that under high pressure at low pressure. It can be seen that ultrafine particles can significantly reduce the impact energy consumption of the microbubble generator, reduce the pressure difference between the gas-liquid mixture and the absorption tower, and help reduce the energy consumption of the desulfurization process.

[0090] Comparative Example 3

[0091] The same as Example 4, except that the mass content of ferrous sulfide in the foaming liquid is 8 g / L.

[0092] After 48 hours of operation, the gas content of the gas-liquid mixture leaving the microbubble generator was measured by a conductivity probe to be 42.7%, and the hydrogen sulfide content of the purified gas extracted from the top of the absorption tower was 48 mg / Nm 3 , 1.5L / h of desulfurization liquid is carried out in the purified gas.

[0093] By comparing Example 4 and Comparative Example 3, it can be seen that when the solid content in the foaming liquid is 8 g / L, the gas content in the gas-liquid mixture is greater than 40%, and there are too many bubbles in the absorption tower, causing the absorption tower to flood with liquid and poor desulfurization effect.

[0094] Comparative Example 4

[0095] The same as Example 4, except that the particle size of ferrous sulfide in the foaming liquid is 120 μm.

[0096] After 48 hours of operation, the gas content of the gas-liquid mixture leaving the microbubble generator was measured by a conductivity probe to be 25%, and the hydrogen sulfide content of the purified gas extracted from the top of the absorption tower was 57 mg / Nm 3 .

[0097] By comparing Example 4 and Comparative Example 4, it can be seen that the added solid particles are large, the gas content of the gas-liquid mixture is low, and the bubbles are large, resulting in poor desulfurization effect.

[0098] 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 low energy consumption desulfurization method, characterized in that: The method comprises the following steps: (1) contacting an acidic gas and a foaming liquid in a microbubble generator to generate microbubbles to obtain a gas-liquid mixture; wherein the foaming liquid comprises ultrafine particles and a complex iron desulfurization liquid I, and the particle size of the ultrafine particles is 10-100 μm; (2) the mixture and the complex iron desulfurization liquid II are reversely contacted in an absorption tower to cause an oxidation-reduction reaction to obtain purified gas and desulfurized rich liquid; (3) subjecting the desulfurized rich liquid to oxidation regeneration with air in an oxidation regeneration tank to obtain regenerated gas, regenerated lean liquid and regenerated sulfur slurry; (4) Separating the regenerated sulfur slurry in a separator to obtain sulfur and filtrate; wherein the regenerated lean liquid and / or filtrate is returned to the absorption tower for recycling.

2. The method according to claim 1, wherein: The acid gas is a gas containing hydrogen sulfide; preferably, the content of hydrogen sulfide is 1-30g / Nm 3 , preferably 5-10g / Nm 3 .

3. The method according to claim 1 or 2, wherein: The particle size of the ultrafine particles is 20-60 μm; Preferably, the ultrafine particles are sulfur and / or ferrous sulfide, preferably sulfur; Preferably, in the foaming liquid, the content of the ultrafine particles is 1-6 g / L, preferably 2.5-4 g / L.

4. The method according to any one of claims 1 to 3, wherein: The dosage ratio of the acid gas and the foaming liquid is 1Nm 3 : 1-3.5L, preferably 1Nm 3 : 1.5-2.5L; Preferably, the contact time between the acid gas and the foaming liquid is 5-30 s, preferably 15-25 s.

5. The method according to any one of claims 1 to 4, wherein: The microbubble generator comprises a bubble generator and a circulation pump; wherein the bubble generator is arranged inside the absorption tower and located at the lower end of the absorption tower; and the circulation pump is arranged outside the absorption tower.

6. The method according to claim 5, wherein: The circulation flow rate of the circulation pump is 5-15 L / h, preferably 8-12 L / h; Preferably, the outlet pressure of the circulation pump is 50-150 kPa, preferably 80-120 kPa.

7. The method according to any one of claims 1 to 6, wherein: The complex iron desulfurization liquid II is the same as the complex iron desulfurization liquid I.

8. The method according to any one of claims 1 to 7, wherein: Based on 1Nm 3 The acid gas, the amount of the complex iron desulfurization liquid II is 10-30L, preferably 15-25L; Preferably, the operating conditions of the absorption tower include: absorption temperature of 30-50°C, preferably 40-45°C, and absorption pressure of 10-80 kPa, preferably 20-50 kPa.

9. The method according to any one of claims 1 to 8, wherein: Based on 1Nm 3 The acid gas, the air usage ratio is 5-15L, preferably 1:8-12L; Preferably, the operating conditions of the regeneration tower include: a regeneration temperature of 30-50°C, preferably 40-45°C; and a regeneration pressure of 2-10 kPa, preferably 4-6 kPa.

10. The method according to any one of claims 1 to 9, wherein: The separator comprises a filter and / or a centrifuge, preferably a filter.

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