Process for the preparation of sulfur

Abstract

The present application relates to the technical field of sulfur recovery, and particularly relates to a preparation method of sulfur, which comprises at least one alternating regeneration step and production step after catalyst deactivation; the regeneration step comprises passing first Claus tail gas and first oxygen-containing raw material into a selective oxidation reactor for catalyst regeneration, and the oxygen volume concentration in the gas phase at the outlet of the reactor during regeneration is not less than 5%; the production step comprises passing second Claus tail gas and second oxygen-containing raw material into the selective oxidation reactor for catalytic reaction, and the oxygen volume concentration in the gas phase at the outlet of the reactor during reaction is not more than 2%. The method can realize efficient regeneration of the catalyst, prolong the service life, and is simple, environmentally friendly and free of secondary pollution during the regeneration process, so that the device can be operated for a long time and sulfur can be produced efficiently.

Description

Technical Field

[0001] This invention relates to the field of sulfur recovery technology, and more specifically to a method for preparing sulfur. Background Technology

[0002] The core technology of the Super Claus process lies in the use of advanced H2S selective oxidation catalysts in the reaction section. In recent years, with the vigorous development of coal chemical industry, my country's H2S selective oxidation catalysts have developed rapidly. New selective oxidation catalysts mainly use non-toxic and harmless iron oxide as the active component, while adding appropriate promoters, resulting in catalysts with high activity. However, during the application of selective oxidation catalysts, with the extension of service life, improper operation and other reasons can cause the catalyst to deactivate before reaching its service life, resulting in a significant decrease in activity. This affects the normal sulfur recovery rate of the unit and causes serious exceedances of SO2 emissions in the flue gas, leading to the unit's inability to operate normally.

[0003] CN 112337501 A discloses a method for preparing a sulfurized regenerated hydrogenation catalyst, comprising: first wetting the carbonized deactivated hydrogenation catalyst with an oxygen-containing organic solvent, then subjecting it to a mild sulfur burning and carbon burning treatment, cooling it down, and then vacuum impregnating it with a water-soluble sulfur-containing composite solution, followed by heat treatment to obtain the sulfurized regenerated hydrogenation catalyst.

[0004] CN 112076804A discloses a method for regenerating and activating a catalyst for the hydrotreating of heavy distillate oil. The method involves placing the regenerated catalyst in a solution containing inorganic and organic chelating ligands, and impregnating it under acoustic conditions. The impregnated sample is then dried at room temperature, followed by a two-step heat treatment to obtain an activated catalyst. This invention is mainly used for the regeneration of hydrotreating catalysts, but the operation process is relatively complex and cannot achieve online catalyst regeneration. Summary of the Invention

[0005] The purpose of this invention is to overcome the problem in the prior art where catalysts deactivate before reaching their service life due to improper operation of the Claus process unit, resulting in a significant decrease in activity. This affects the normal sulfur recovery rate of the unit and causes serious SO2 emissions from the flue gas to exceed standards, leading to the unit's inability to operate normally. The invention provides a method for sulfur preparation that enables online catalyst regeneration. The regeneration process is simple and easy to implement, reducing the frequency of catalyst replacement and lowering the unit's operating costs, thus providing significant economic and social benefits.

[0006] To achieve the above objectives, the present invention provides a method for preparing sulfur, wherein after catalyst deactivation, the method involves at least one alternating regeneration step and production step.

[0007] The regeneration step includes passing the first Claus tail gas and the first oxygen-containing feed into a selective oxidation reactor for catalyst regeneration, wherein the oxygen volume concentration in the gas phase at the reactor outlet is not less than 5% during regeneration.

[0008] The production step includes passing the second Claus tail gas and the second oxygen-containing feedstock into a selective oxidation reactor for catalytic reaction, wherein the oxygen volume concentration in the gas phase at the reactor outlet is not greater than 2% during the reaction.

[0009] Through the above technical solution, the present invention has the following advantages:

[0010] The method of this invention can achieve efficient catalyst regeneration, extend its service life, and the regeneration process is simple, environmentally friendly, and produces no secondary pollution, ensuring long-term operation of the equipment and efficient sulfur production. Attached Figure Description

[0011] Figure 1 This is a preferred apparatus and flowchart for preparing sulfur according to the present invention.

[0012] Explanation of reference numerals in the attached figures

[0013] 1. Reactor; 7. Secondary heater;

[0014] 2. Waste heat boiler; 8. Secondary reactor;

[0015] 3. Primary sulfur condenser; 9. Tertiary sulfur condenser;

[0016] 4. Primary heater; 10. Tertiary heater;

[0017] 5. Primary reactor; 11. Tertiary reactor;

[0018] 6. Two-stage sulfur condenser; 12. Four-stage sulfur condenser;

[0019] 13. Four-stage heater; 16. Incinerator;

[0020] 14. Select an oxidation reactor; 17. Use an alkaline scrubbing tower;

[0021] 15. Five-stage sulfur condenser; 18. Chimney. Detailed Implementation

[0022] The endpoints and any values ​​of the ranges disclosed herein 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 the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0023] This invention provides a method for preparing sulfur, wherein after catalyst deactivation, the method involves at least one alternating regeneration step and production step;

[0024] The regeneration step includes passing the first Claus tail gas and the first oxygen-containing feed into a selective oxidation reactor for catalyst regeneration, wherein the oxygen volume concentration in the gas phase at the reactor outlet is not less than 5% during regeneration.

[0025] The production step includes passing the second Claus tail gas and the second oxygen-containing feedstock into a selective oxidation reactor for catalytic reaction, wherein the oxygen volume concentration in the gas phase at the reactor outlet is not greater than 2% during the reaction.

[0026] The method of this invention can achieve efficient catalyst regeneration, extend its service life, and the regeneration process is simple, environmentally friendly, and produces no secondary pollution, ensuring long-term operation of the equipment and efficient sulfur production.

[0027] According to a preferred embodiment of the present invention, the H2S concentration in the first Claus tail gas is 0.3-1%, and the SO2 concentration is ≤0.04%. By adopting the aforementioned preferred scheme, the sulfur production efficiency can be further improved.

[0028] According to a preferred embodiment of the present invention, the H2S concentration in the second Claus exhaust gas is 0.3-1%.

[0029] According to a preferred embodiment of the present invention, the inlet temperature of the selective oxidation reactor during catalyst regeneration is higher than that during the selective oxidation reactor during catalytic reaction, preferably 5-40°C higher, more preferably 5-20°C higher, and even more preferably 10-15°C higher. By adopting the aforementioned preferred embodiment, the sulfur production efficiency can be further improved.

[0030] In this invention, the oxygen volume concentration in the reactor outlet gas phase during regeneration is only required to be within the range described above in this application. According to a preferred embodiment of this invention, the oxygen volume concentration in the reactor outlet gas phase during regeneration is 5-10%. By adopting the aforementioned preferred scheme, the sulfur production efficiency can be further improved.

[0031] In this invention, the oxygen volume concentration in the reactor outlet gas phase during the reaction is within the range described above in this application. According to a preferred embodiment of this invention, the oxygen volume concentration in the reactor outlet gas phase during the reaction is 0.5-2%. By adopting the aforementioned preferred scheme, the sulfur production efficiency can be further improved.

[0032] According to a preferred embodiment of the present invention, the oxygen volume concentration in the first oxygen-containing raw material is 10% or more, and the other gases besides oxygen include inert gases, such as at least one of nitrogen, argon, and helium.

[0033] According to a preferred embodiment of the present invention, the oxygen volume concentration in the second oxygen-containing raw material is 5-21%.

[0034] According to a preferred embodiment of the present invention, the first oxygen-containing raw material and the second oxygen-containing raw material may be air.

[0035] According to a preferred embodiment of the present invention, the catalyst regeneration conditions include a volume ratio of the first Claus tail gas to the first oxygen-containing feedstock of 10:1-5:1, preferably 6:1-8:1. By adopting the aforementioned preferred scheme, the catalyst regeneration efficiency can be further improved, thereby increasing the sulfur production efficiency.

[0036] According to a preferred embodiment of the present invention, the conditions for catalyst regeneration include: selecting an inlet temperature of 180-250°C, preferably 200-240°C, for the oxidation reactor.

[0037] According to a preferred embodiment of the present invention, the conditions for catalyst regeneration include: a regeneration temperature of 180-260°C, preferably 200-250°C.

[0038] According to a preferred embodiment of the present invention, the conditions for catalyst regeneration include a regeneration time of 10-72 h, preferably 24-60 h.

[0039] According to a preferred embodiment of the present invention, the conditions for the catalytic reaction include: a volume ratio of the second Claus tail gas to the second oxygen-containing feedstock of 20:1-5:1, preferably 15:1-7:1. By adopting the aforementioned preferred scheme, the sulfur production efficiency can be further improved.

[0040] According to a preferred embodiment of the present invention, the conditions for the catalytic reaction include: selecting an inlet temperature of 180-230°C, preferably 200-220°C, for the oxidation reactor.

[0041] According to a preferred embodiment of the present invention, the conditions for the catalytic reaction include: a reaction temperature of 170-240°C, preferably 200-240°C.

[0042] According to a preferred embodiment of the present invention, the conditions for the catalytic reaction include: a reaction time of 8-72 h, preferably 24-60 h.

[0043] According to a preferred embodiment of the present invention, after the catalytic reaction is completed, the inlet temperature of the selective oxidation reactor is reduced to 170-200°C, preferably 180-190°C; during regeneration, the reactor inlet temperature is increased to the regeneration temperature at a rate of 10-20°C / h; after regeneration is completed, the inlet temperature of the selective oxidation reactor is reduced to the reaction temperature. By adopting the aforementioned preferred scheme, the catalyst regeneration efficiency can be further improved, and the sulfur production efficiency can be increased.

[0044] According to a preferred embodiment of the present invention, the regenerated gas phase is sent to an incinerator for incineration and then discharged after being washed in an alkaline scrubbing tower.

[0045] In this invention, the active component of the catalyst in the selective oxidation reactor can be a conventional hydrogen sulfide selective oxidation catalyst for sulfur production, and the active component of the catalyst in the selective oxidation reactor includes iron oxide.

[0046] In existing technologies, insufficient oxygen levels can cause catalyst sulfidation in selective oxidation reactors, leading to loss of catalytic activity and excessively high concentrations of SO2 and H2S in the exhaust gas. The main active component of the catalyst in the selective oxidation reactor is Fe2O3. When the oxygen supply to the reactor is insufficient, Fe2O3 reacts with H2S to produce FeS. FeS is an active agent in the Claus reverse reaction, promoting the reaction of sulfur with water to produce H2S and SO2, resulting in excessively high concentrations of SO2 and H2S in the exhaust gas and increased SO2 emissions. The regeneration method of this invention can solve the aforementioned problems, achieving efficient catalyst regeneration and efficient sulfur preparation. The relevant reactions for catalyst regeneration are:

[0047] FeS is the active agent in the reverse Claus reaction: 3S + 2H₂O → 2H₂S + SO₂ (1)

[0048] The regeneration process of this invention uses Claus tail gas and oxygen feedstock to regenerate the selective oxidation catalyst. FeS reacts with O2 to generate Fe2(SO4)3 and Fe2O3. In the presence of H2S, H2S reacts with Fe2(SO4)3 to generate FeSO4. FeSO4 continues to react with H2S to generate FeS. FeS is then oxidized by oxygen to Fe2O3.

[0049] 3FeS + 6.75O2 →Fe2(SO4)3+0.5Fe2O3 (2)

[0050] Fe2(SO4)3+H2S→2FeSO4+H2SO4+S (3)

[0051] 2FeSO4+8H2S→8FeS+8S+8H2O (4)

[0052] After reaction (4), reaction (2) continues to occur, and the cycle repeats until FeS is converted into Fe2O3, and the activation is completed.

[0053] According to a preferred embodiment of the present invention, the first Claus tail gas and the second Claus tail gas are each obtained independently from hydrogen sulfide feedstock and oxygen feedstock through at least one, preferably 3-4, Claus reactions.

[0054] The term "Rouse tail gas" refers to the gas phase discharge from the last stage sulfur condenser in the upstream process of the selective oxidation reactor.

[0055] like Figure 1 As shown, the present invention provides a sulfur preparation device, which includes: a reactor 1, a waste heat boiler 2, a primary sulfur condenser 3, a primary heater 4, a primary reactor 5, a secondary sulfur condenser 6, a secondary heater 7, a secondary reactor 8, a tertiary sulfur condenser 9, a tertiary heater 10, a tertiary reactor 11, a quaternary sulfur condenser 12, a quaternary heater 13, a selective oxidation reactor 14, a quinary sulfur condenser 15, an incinerator 16, an alkaline scrubbing tower 17, and a chimney 18, connected in series; liquid sulfur outlets are provided in each sulfur condenser and connected to a liquid sulfur pool; a regenerated air pipeline is connected to the connecting pipeline between the quaternary sulfur condenser 12 and the quaternary heater 13.

[0056] The preparation process includes: selecting oxidation reactor 14, catalyzing the conversion of hydrogen sulfide to sulfur under the action of a fresh catalyst, until the catalyst is deactivated,

[0057] (1) Gradually reduce the inlet temperature of the selective oxidation reactor 14 to 170-200℃, preferably 180-190℃;

[0058] (2) Adjust (reduce) the air distribution in the reactor so that the H2S concentration at the inlet of the selective oxidation reactor (Claus tail gas) is 0.3%-1% and the SO2 concentration is ≤0.04%. This gas (first Claus tail gas) serves as the regeneration acid gas for the selective oxidation catalyst.

[0059] (3) The first oxygen-containing raw material, such as air, is introduced before the fourth stage heater so that the volume ratio of the first Claus tail gas to the first oxygen-containing raw material is 10:1-5:1 (under this ratio range, the oxygen volume concentration in the gas phase at the reactor outlet is not less than 5% during regeneration) to carry out regeneration and make the selective oxidation reactor operate in an oxygen-rich state.

[0060] (4) The catalyst is regenerated by gradually increasing the reaction temperature by 10-20℃ / h until the inlet temperature is raised to 180-250℃, preferably 200-240℃, and the regeneration temperature is 180-260℃, preferably 200-250℃, for 10-72 hours, preferably 24-60h.

[0061] (5) After regeneration, gradually reduce the reactor inlet temperature to 180-230℃, preferably 200-220℃;

[0062] (6) Adjust the air distribution in the incinerator so that the H2S concentration at the inlet of the selective oxidation reactor is between 0.3% and 1%;

[0063] (7) Adjust the amount of regenerated air (the volume ratio of the second Claus tail gas and the second oxygen-containing raw material is 20:1-5:1, preferably 15:1-7:1) so that the O2 content at the outlet of the selective oxidation reactor is about 0.5%-2% (V) and the operation is maintained under super-oxygen conditions.

[0064] (8) Normal production commenced.

[0065] The following will be adopted Figure 1 The present invention will be described in detail with reference to embodiments of the scheme. In the following embodiments, the H2S conversion rate and sulfur production selectivity parameters were measured by a sulfur microreactor evaluation device; all raw materials were commercially available products.

[0066] Example 1

[0067] A 15,000-ton / year sulfur recovery unit uses selective oxidation (COO) to recover sulfur. Two years after operation, calibration of the COO reactor revealed a significant decrease in H2S conversion and sulfur selectivity, indicating severe catalyst deactivation. Historical records showed no bed temperature runaway. Preliminary assessment suggests the catalyst was previously in an oxygen-deficient state, necessitating catalyst regeneration. The regeneration steps are as follows:

[0068] (1) Gradually reduce the inlet temperature of the selective oxidation reactor to 190℃;

[0069] (2) Reduce the gas supply to the reactor so that the H2S concentration at the inlet of the selective oxidation reactor (Claus tail gas) is around 0.7% and the SO2 concentration is ≤0.04%. This gas is used as the regeneration acid gas for the selective oxidation catalyst.

[0070] (3) Air is introduced before the fourth stage heater for regeneration. The volume ratio of Claus tail gas to oxygen is controlled at 6:1 (under this ratio range, the oxygen volume concentration in the reactor outlet gas phase during regeneration is not less than 5%), so that the selective oxidation reactor operates in an oxygen-rich state.

[0071] (4) The catalyst is regenerated by gradually increasing the reaction temperature by 10℃ / h until the inlet temperature is raised to 240℃. The regeneration temperature is 260℃ and the regeneration time is 48 hours.

[0072] (5) After regeneration is complete, gradually reduce the reactor inlet temperature to 230°C;

[0073] (6) Adjust the air distribution in the incinerator so that the H2S concentration at the inlet of the selective oxidation reactor is around 0.5%;

[0074] (7) Adjust the amount of regenerated air so that the O2 content at the outlet of the selective oxidation reactor is about 1.5% (V) (at this time, the volume ratio of Claus tail gas to regenerated air is in the range of 20:1-5:1) and maintain operation under super-oxygen conditions;

[0075] (8) Normal production commenced.

[0076] After activation, normal operating conditions are restored, and the H2S conversion rate is above 95%, the selectivity for sulfur production is >90%, which is comparable to the activity of fresh catalyst, and the regeneration effect is good.

[0077] Example 2

[0078] A 0.5 million tons / year sulfur recovery unit uses selective oxidation (COO) to recover sulfur. One year after operation, calibration of the COO reactor revealed a significant decrease in H2S conversion and sulfur selectivity, indicating severe catalyst deactivation. Historical records showed no bed temperature runaway. Preliminary assessment suggests the catalyst was previously in an oxygen-deficient state, necessitating catalyst regeneration. The regeneration steps are as follows:

[0079] (1) Gradually reduce the inlet temperature of the selective oxidation reactor by 180℃;

[0080] (2) Reduce the gas supply to the reactor so that the H2S concentration at the inlet of the selective oxidation reactor (Claus tail gas) is around 0.8% and the SO2 concentration is ≤0.04%. This gas is used as the regeneration acid gas for the selective oxidation catalyst.

[0081] (3) Air is introduced before the fourth stage heater for regeneration. The volume ratio of Claus tail gas to oxygen is controlled at 7:1 (under this ratio range, the oxygen volume concentration in the reactor outlet gas phase during regeneration is not less than 5%), so that the selective oxidation reactor operates in an oxygen-rich state.

[0082] (4) The catalyst is regenerated by gradually increasing the reaction temperature by 20℃ / h until the inlet temperature is raised to 220℃. The regeneration temperature is 240℃ and the regeneration time is 24 hours.

[0083] (5) After regeneration is complete, gradually reduce the reactor inlet temperature to 205°C;

[0084] (6) Adjust the air distribution in the incinerator so that the H2S concentration at the inlet of the selective oxidation reactor is around 0.4%;

[0085] (7) Adjust the amount of regenerated air so that the O2 content at the outlet of the selective oxidation reactor is about 1.0% (V) (at this time, the volume ratio of Claus tail gas to regenerated air is in the range of 20:1-5:1) and maintain operation under super-oxygen conditions;

[0086] (8) Normal production commenced.

[0087] After activation, normal operating conditions are restored, and the H2S conversion rate is above 95%, the selectivity for sulfur production is >90%, which is comparable to the activity of fresh catalyst, and the regeneration effect is good.

[0088] Example 3

[0089] A 10,000-ton / year sulfur recovery unit uses selective oxidation (COO) to recover sulfur. After three years of operation, calibration of the COO reactor revealed a significant decrease in H2S conversion and sulfur production selectivity, indicating severe catalyst deactivation. A review of historical records showed no evidence of bed runaway. Preliminary assessment suggests the catalyst was previously in an oxygen-deficient state, necessitating catalyst regeneration. The regeneration steps are as follows:

[0090] (1) Gradually reduce the inlet temperature of the selective oxidation reactor to 185℃;

[0091] (2) Reduce the gas supply to the reactor so that the H2S concentration at the inlet of the selective oxidation reactor (Claus tail gas) is around 0.3% and the SO2 concentration is ≤0.04%. This gas is used as the regeneration acid gas for the selective oxidation catalyst.

[0092] (3) Air is introduced before the fourth stage heater for regeneration. The volume ratio of Claus tail gas to oxygen is controlled at 8:1 (under this ratio range, the oxygen volume concentration in the reactor outlet gas phase during regeneration is not less than 5%), so that the selective oxidation reactor operates in an oxygen-rich state.

[0093] (4) The catalyst is regenerated by gradually increasing the reaction temperature by 15℃ / h until the inlet temperature is raised to 210℃. The regeneration temperature is 220℃ and the regeneration time is 32 hours.

[0094] (5) After regeneration is complete, gradually reduce the reactor inlet temperature to 200°C;

[0095] (6) Adjust the air distribution in the incinerator so that the H2S concentration at the inlet of the selective oxidation reactor is around 0.5%;

[0096] (7) Adjust the amount of regenerated air so that the O2 content at the outlet of the selective oxidation reactor is about 0.8% (V) (the volume ratio of the second Claus tail gas and the second oxygen-containing raw material is 20:1-5:1, preferably 15:1-7:1), and maintain operation under super-oxygen conditions.

[0097] (8) Normal production commenced.

[0098] The regeneration process strictly controls the catalyst bed reaction temperature below 280℃. When the temperature exceeds this range, cooling is achieved through other methods that do not affect catalyst activity, such as reducing the inlet H2S concentration or lowering the reactor inlet temperature. After activation, normal operating conditions are restored, and the H2S conversion rate is above 95%, with a sulfur selectivity >90%, comparable to that of fresh catalyst, indicating a good regeneration effect.

[0099] Example 4

[0100] Same as Example 1, except that in step (3), the amount of air introduced before the fourth stage heater is adjusted so that the volume ratio of regenerated acid gas to the first oxygen-containing raw material is 10:1.

[0101] The H2S conversion rate is above 90%, and the selectivity for sulfur formation is >85%.

[0102] Example 5

[0103] Same as Example 1, except that (2) the air distribution of the reactor is adjusted so that the H2S concentration at the inlet of the selective oxidation reactor (Claus tail gas) is 1.2%.

[0104] The H2S conversion rate is above 85%, and the selectivity for sulfur formation is >83%.

[0105] Example 6

[0106] Same as Example 1, except that the regeneration temperature inlet is maintained at 190°C.

[0107] The H2S conversion rate is above 90%, and the selectivity for sulfur formation is >80%.

[0108] Comparative Example 1

[0109] A 20,000-ton / year sulfur recovery unit uses selective oxidation to recover sulfur. The SO2 emission concentration in the flue gas of the sulfur recovery unit is consistently high. Sampling and analysis of the H2S concentration at the inlet and outlet of the selective oxidation reactor showed that the H2S conversion rate of the catalyst in the selective oxidation reactor was between 20% and 40%, and the selectivity for sulfur production was between 20% and 45%. The catalyst was severely deactivated, so the unit was shut down for catalyst replacement. The catalyst was only used for two and a half years, resulting in high operating costs for the unit.

[0110] Comparative Example 2

[0111] Same as Example 1, except that step (2) is not performed, that is, the regenerated acid gas is not passed through.

[0112] After regeneration, the H2S conversion rate is above 78%, and the selectivity for sulfur formation is >70%.

[0113] Comparative Example 3

[0114] Same as Example 1, except that in step (3), the amount of air introduced before the fourth stage heater is adjusted so that the oxygen content in the contact regeneration gas phase product stream is 2%.

[0115] After regeneration, the H2S conversion rate is over 80%, and the selectivity for sulfur formation is >83%.

[0116] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing sulfur, characterized in that, This preparation method involves at least one alternating regeneration and production step after catalyst deactivation; The regeneration step includes passing the first Claus tail gas and the first oxygen-containing feed into a selective oxidation reactor to regenerate the catalyst, wherein the oxygen volume concentration in the gas phase at the reactor outlet is not less than 5% during regeneration; The production step includes passing the second Claus tail gas and the second oxygen-containing feedstock into a selective oxidation reactor for catalytic reaction, wherein the oxygen volume concentration in the gas phase at the reactor outlet is not greater than 2% during the reaction. The H2S concentration in the first Claus exhaust gas is 0.3-1%, and the SO2 concentration is ≤0.04%. The oxygen volume concentration in the first oxygen-containing raw material is above 10%; The volume ratio of the first Claus exhaust gas to the first oxygen-containing feedstock is 10:1-5:

1.

2. The preparation method according to claim 1, wherein, The H2S concentration in the second Claus exhaust gas is 0.3-1%; and / or The oxygen volume concentration in the reactor outlet gas phase during the reaction is 0.5-2%.

3. The preparation method according to claim 1, wherein, The inlet temperature of the oxidation reactor is selected during catalyst regeneration to be higher than that selected during the catalytic reaction.

4. The preparation method according to claim 3, wherein, The inlet temperature of the oxidation reactor is selected during catalyst regeneration at a rate 5-40°C higher than that selected during the catalytic reaction.

5. The preparation method according to claim 3, wherein, The inlet temperature of the oxidation reactor is selected to be 5-20°C higher during catalyst regeneration than that selected during catalytic reaction.

6. The preparation method according to claim 3, wherein, The inlet temperature of the oxidation reactor selected during catalyst regeneration is 10-15°C higher than that selected during the catalytic reaction.

7. The preparation method according to claim 1, wherein, The preparation method involves alternating regeneration and production steps 1-2 times after the catalyst is deactivated.

8. The preparation method according to claim 1, wherein, The oxygen volume concentration in the second oxygen-containing raw material is 5-21%.

9. The preparation method according to claim 1, wherein, The conditions for catalyst regeneration include: Select an oxidation reactor inlet temperature of 180-250℃; and / or The regeneration temperature is 180-260℃; and / or The regeneration time is 10-72 hours.

10. The preparation method according to claim 9, wherein, The conditions for catalyst regeneration include: The volume ratio of the first Claus exhaust gas to the first oxygen-containing feedstock is 6:1-8:1; and / or Select an oxidation reactor inlet temperature of 200-240℃; and / or The regeneration temperature is 200-250℃; and / or The regeneration time is 24-60 hours.

11. The preparation method according to claim 1, wherein, The conditions for the catalytic reaction include: The volume ratio of the second Claus exhaust gas to the second oxygen-containing feedstock is 20:1-5:1; and / or Select an oxidation reactor inlet temperature of 180-230℃; and / or The reaction temperature is 170-240℃; and / or The reaction time is 8-72 hours.

12. The preparation method according to claim 11, wherein, The conditions for the catalytic reaction include: The volume ratio of the second Claus exhaust gas to the second oxygen-containing feedstock is 15:1-7:1; and / or Select an oxidation reactor inlet temperature of 200-220℃; and / or The reaction temperature is 200-240℃; and / or The reaction time is 24-60 hours.

13. The preparation method according to claim 1, wherein, After the catalytic reaction is completed, the inlet temperature of the selective oxidation reactor is reduced to 170-200℃; During regeneration, the reactor inlet temperature is increased to the regeneration temperature at a rate of 10-20℃ / h; After regeneration, reduce the inlet temperature of the selective oxidation reactor to the reaction temperature.

14. The preparation method according to claim 13, wherein, After the catalytic reaction is completed, the inlet temperature of the selective oxidation reactor is reduced to 180-190℃.

15. The preparation method according to claim 1, wherein, The active component of the catalyst in the selective oxidation reactor includes iron oxide.

16. The preparation method according to any one of claims 1-15, wherein, The first Claus tail gas and the second Claus tail gas are each obtained independently from hydrogen sulfide feedstock and oxygen feedstock through at least one reaction.

17. The preparation method according to claim 16, wherein, The first Claus tail gas and the second Claus tail gas are each obtained independently from hydrogen sulfide feedstock and oxygen feedstock through 3-4 reactions.

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