Easily-regenerated ferric oxide desulfurizer and preparation method thereof

Abstract

The invention discloses an easy-to-regenerate iron oxide desulfurizer and a preparation method thereof, and belongs to the technical field of desulfurization, by coating the surface of iron oxide with a polyethylene derivative of benzimidazole and cyclodextrin, the reaction selectivity of the desulfurizer and hydrogen sulfide is improved, deposition of iron sulfide on the surface of the desulfurizer is reduced, and the desulfurization efficiency is improved. Therefore, the generation of ferrous sulfide is avoided, and the regeneration capacity of the desulfurizer is improved; due to the wrapping of the polymer, the chemical stability and the thermal stability of the desulfurizer are improved, so that the desulfurizer keeps stable performance in the use process and the regeneration process, and the prepared desulfurizer is high in hydrogen sulfide adsorption capacity, high in sulfur capacity, easy to regenerate and capable of being used for removing hydrogen sulfide.

Description

Technical Field

[0001] The invention belongs to the technical field of desulfurization, and in particular is an easily regenerable iron oxide desulfurizer and a preparation method thereof. Background Art

[0002] Iron oxide desulfurizer is a high-efficiency gas purifier made of iron oxide as the main active component and other promoters. It has a high removal performance for hydrogen sulfide, and also has a certain removal effect on mercaptan organic sulfur and most nitrogen oxides.

[0003] In the process of removing hydrogen sulfide, the iron oxide desulfurizer continuously generates iron sulfide or ferrous sulfide. In the presence of oxygen, iron sulfide can be oxidized and regenerated into iron oxide, while the generation of ferrous sulfide will reduce the activity of the iron oxide desulfurizer, thus affecting its desulfurization effect; in addition, ferrous sulfide is not easy to regenerate, which in turn affects the regeneration capacity of the desulfurizer. Therefore, developing a new type of iron oxide desulfurizer to avoid the generation of ferrous disulfide is of great significance to improving the desulfurization performance of the desulfurizer, and improving its stability and regeneration capacity. Summary of the invention

[0004] To solve the above problems, the purpose of the present invention is to provide an easily regenerable iron oxide desulfurizer and a preparation method thereof.

[0005] In order to achieve the above object, the present invention is implemented through the following technical solutions: The invention discloses an easily regenerable iron oxide desulfurizer. The polyethylene derivative is prepared by polymerizing terminal alkenyl cyclodextrin and terminal alkenyl benzimidazole, and then mixed with soluble iron salt to obtain the polyethylene derivative.

[0006] The terminal olefin cyclodextrin is prepared according to the following method: Add β-cyclodextrin and 4-vinylphenol to dimethylformamide, stir to dissolve, add triphenylphosphine and diisopropyl azodicarboxylate, react at 25-40°C for 5-10 hours, remove the solvent by distillation under reduced pressure, add dichloromethane to dissolve the obtained residue and filter it, extract the obtained filtrate with water for 3-5 times, combine the organic layers, and finally remove the solvent by distillation under reduced pressure to obtain terminal olefin cyclodextrin.

[0007] The mass ratio of the beta-cyclodextrin, 4-vinylphenol, dimethylformamide, triphenylphosphine, diisopropyl azodicarboxylate, dichloromethane and water is 1: 0.1-0.2: 10-15: 0.25-0.35: 0.2-0.3: 8-10: 8-10.

[0008] The terminal alkenyl benzimidazole is prepared according to the following method: Add 2-hydroxymethylbenzimidazole and 4-vinylphenol to dimethylformamide, stir and dissolve, then add triphenylphosphine and diisopropyl azodicarboxylate, react at 25-40°C for 5-10 hours, remove the solvent by distillation under reduced pressure, add dichloromethane to dissolve the obtained residue and filter it, extract the obtained filtrate with water for 3-5 times, combine the organic layers, and finally remove the solvent by distillation under reduced pressure to obtain terminal alkenylbenzimidazole.

[0009] The mass ratio of the 2-hydroxymethylbenzimidazole, 4-vinylphenol, dimethylformamide, triphenylphosphine, diisopropyl azodicarboxylate, dichloromethane and water is 1:0.8-1:10-15:2-2.8:1.4-2:5-10:5-10.

[0010] The method for preparing the easily regenerable iron oxide desulfurizer comprises the following steps: 1) Add terminal alkenyl benzimidazole, terminal alkenyl cyclodextrin and azobisisobutyronitrile to toluene, heat to 50-90°C for reaction for 10-20 hours, and after the reaction is completed, remove the solvent by vacuum distillation, wash the obtained solid with acetone for 3-5 times, and dry to obtain a polyethylene derivative; 2) Add iron salt into water, stir to dissolve, then add the polyethylene derivative obtained in step 1), stir for 3-5 hours, filter, wash, dry at 100° C. for 5-10 hours, and then calcine at 300-350° C. for 2-4 hours under nitrogen protection to obtain an easily regenerable iron oxide desulfurizer.

[0011] The mass ratio of the terminal alkenyl benzimidazole, the terminal alkenyl cyclodextrin, azobisisobutyronitrile and toluene in step 1) is 1-5:5-20:0.03-0.2:15-50.

[0012] The mass ratio of the iron salt, water and polyethylene derivative in step 2) is 20-80:1000:15-20.

[0013] The iron salt in step 2) is ferric chloride or ferric sulfate.

[0014] The present invention also includes the use of the easily regenerable iron oxide desulfurizer in removing hydrogen sulfide.

[0015] Compared with the prior art, the present invention has the following advantages: The easily regenerable iron oxide desulfurizer of the present invention is prepared by coating the surface of the iron oxide with polyethylene derivatives of benzimidazole and cyclodextrin. The introduction of benzimidazole can improve the reaction selectivity of the desulfurizer with hydrogen sulfide, reduce the deposition of iron sulfide on the surface of the desulfurizer, thereby avoiding the formation of ferrous sulfide and improving the regeneration capacity of the desulfurizer; on the other hand, it can improve the thermal stability of the polyethylene derivative; cyclodextrin significantly improves the adsorption capacity of hydrogen sulfide due to its multi-level pore structure and high specific surface area, and this structure helps to increase the oxygen vacancies of the iron oxide desulfurizer, thereby improving its catalytic performance and regeneration performance; and cyclodextrin can form an inclusion complex with hydrogen sulfide, which helps to stably fix hydrogen sulfide in the desulfurizer, promote the dissociation of hydrogen sulfide by heating, and further improve its regeneration performance.

[0016] The easily regenerable iron oxide desulfurizer of the present invention is prepared by coating the surface of the iron oxide with a polyethylene derivative. On the one hand, the polymer forms a protective film on the surface of the iron oxide particles, which reduces the agglomeration between the iron oxide particles, helps to maintain the specific surface area of ​​the iron oxide, and improves its adsorption performance. On the other hand, due to the coating of the polymer, the chemical stability and thermal stability of the desulfurizer are increased, so that the performance of the desulfurizer is kept stable during use and regeneration.

[0017] The desulfurizer prepared by the invention has strong hydrogen sulfide adsorption capacity, high sulfur capacity and easy regeneration, and can be used for removing hydrogen sulfide. DETAILED DESCRIPTION

[0018] In order to better understand the technical solution of the present invention, the above content of the present invention is further described in detail below through specific implementation methods in the form of embodiments, but this should not be understood as the scope of the above subject matter of the present invention being limited to the following examples. All technologies realized based on the above content of the present invention belong to the scope of the present invention.

[0019] Example 1 Preparation of terminal olefin cyclodextrin: Add 1kg of β-cyclodextrin and 0.1kg of 4-vinylphenol to 10kg of dimethylformamide, stir to dissolve, then add 0.25kg of triphenylphosphine and 0.2kg of diisopropyl azodicarboxylate, react at 25°C for 10h, remove the solvent by distillation under reduced pressure, add 8kg of dichloromethane to the obtained residue to dissolve and then filter, extract the obtained filtrate with 8kg of water for 3 times, combine the organic layers, and finally remove the solvent by distillation under reduced pressure to obtain terminal olefin cyclodextrin.

[0020] Preparation of terminal alkenyl benzimidazole: 1 kg of 2-hydroxymethylbenzimidazole and 0.8 kg of 4-vinylphenol were added to 10 kg of dimethylformamide, stirred to dissolve, then 2 kg of triphenylphosphine and 1.4 kg of diisopropyl azodicarboxylate were added, and the mixture was reacted at 25 °C for 10 h. The solvent was removed by distillation under reduced pressure, 5 kg of dichloromethane was added to the residue to dissolve it, and then it was filtered. The filtrate was extracted 3 times with 5 kg of water, the organic layers were combined, and the solvent was removed by distillation under reduced pressure to obtain terminal alkenylbenzimidazole. 1 H NMR (300 MHz, DMSO- d 6 , 298 K) δ 12.09(s, 1H), 7.43-7.68 (m, 4H), 7.12 (d, 2H), 6.91 (d, 2H), 6.75 (t, 1H), 5.73(d,1H), 5.39 (s, 2H), 5.18(d, 1H).

[0021] Preparation of easily regenerable iron oxide desulfurizer: 1 kg of terminal alkenyl benzimidazole, 5 kg of terminal alkenyl cyclodextrin and 0.03 kg of azobisisobutyronitrile were added to 15 kg of toluene, heated to 50°C for reaction for 20 hours, and after the reaction was completed, the solvent was removed by distillation under reduced pressure, and the obtained solid was washed with acetone for 3 times and dried to obtain a polyethylene derivative; Add 2kg of ferric chloride to 100kg of water, stir to dissolve, then add 1.5kg of polyethylene derivative, stir for 3h, filter, wash, dry at 100℃ for 5h, and then calcine at 300℃ for 4h under nitrogen protection to obtain an easily regenerated iron oxide desulfurizer.

[0022] Example 2 Preparation of terminal olefin cyclodextrin: Add 1 kg of β-cyclodextrin and 0.12 kg of 4-vinylphenol to 11 kg of dimethylformamide, stir to dissolve, then add 0.28 kg of triphenylphosphine and 0.21 kg of diisopropyl azodicarboxylate, react at 30°C for 9 hours, remove the solvent by distillation under reduced pressure, add 8.5 kg of dichloromethane to the obtained residue to dissolve and filter, extract the obtained filtrate with 8.5 kg of water for 5 times, combine the organic layers, and finally remove the solvent by distillation under reduced pressure to obtain terminal olefin cyclodextrin.

[0023] Preparation of terminal alkenyl benzimidazole: 1 kg of 2-hydroxymethylbenzimidazole and 0.85 kg of 4-vinylphenol were added to 11 kg of dimethylformamide, stirred to dissolve, then 2.2 kg of triphenylphosphine and 1.5 kg of diisopropyl azodicarboxylate were added, and the mixture was reacted at 26 °C for 9 hours. The solvent was removed by distillation under reduced pressure, and the residue was dissolved by adding 6 kg of dichloromethane and then filtered. The filtrate was extracted 5 times with 6 kg of water, and the organic layers were combined. Finally, the solvent was removed by distillation under reduced pressure to obtain terminal alkenylbenzimidazole.

[0024] Preparation of easily regenerable iron oxide desulfurizer: 2 kg of terminal alkenyl benzimidazole, 8 kg of terminal alkenyl cyclodextrin and 0.09 kg of azobisisobutyronitrile were added to 25 kg of toluene, heated to 60°C for reaction for 18 hours, and after the reaction was completed, the solvent was removed by distillation under reduced pressure, and the obtained solid was washed with acetone 4 times and dried to obtain a polyethylene derivative; Add 3 kg of ferric sulfate into 100 kg of water, stir to dissolve, then add 1.6 kg of polyethylene derivative, stir for 3.5 hours, filter, wash, dry at 100 ° C for 6 hours, and then calcine at 310 ° C for 3.5 hours under nitrogen protection to obtain an easily regenerated iron oxide desulfurizer.

[0025] Example 3 Preparation of terminal olefin cyclodextrin: Add 1kg of β-cyclodextrin and 0.15kg of 4-vinylphenol to 13kg of dimethylformamide, stir to dissolve, then add 0.3kg of triphenylphosphine and 0.24kg of diisopropyl azodicarboxylate, react at 35°C for 8h, remove the solvent by distillation under reduced pressure, add 9kg of dichloromethane to the residue to dissolve and filter, extract the filtrate with 9kg of water for 4 times, combine the organic layers, and finally remove the solvent by distillation under reduced pressure to obtain terminal olefin cyclodextrin.

[0026] Preparation of terminal alkenyl benzimidazole: 1 kg of 2-hydroxymethylbenzimidazole and 0.9 kg of 4-vinylphenol were added to 12 kg of dimethylformamide, stirred to dissolve, then 2.4 kg of triphenylphosphine and 1.7 kg of diisopropyl azodicarboxylate were added, and the mixture was reacted at 30 °C for 8 h. The solvent was removed by distillation under reduced pressure, and the residue was dissolved by adding 7 kg of dichloromethane and then filtered. The filtrate was extracted 4 times with 7 kg of water, and the organic layers were combined. Finally, the solvent was removed by distillation under reduced pressure to obtain terminal alkenylbenzimidazole.

[0027] Preparation of easily regenerable iron oxide desulfurizer: 3 kg of terminal alkenyl benzimidazole, 12 kg of terminal alkenyl cyclodextrin and 0.14 kg of azobisisobutyronitrile were added to 35 kg of toluene, heated to 70°C for reaction for 15 hours, and after the reaction was completed, the solvent was removed by distillation under reduced pressure, and the obtained solid was washed with acetone for 5 times and dried to obtain a polyethylene derivative; Add 5 kg of ferric sulfate into 100 kg of water, stir to dissolve, then add 1.8 kg of polyethylene derivative, stir for 4 hours, filter, wash, dry at 100 ° C for 8 hours, and then calcine at 330 ° C for 3 hours under nitrogen protection to obtain an easily regenerated iron oxide desulfurizer.

[0028] Example 4 Preparation of terminal olefin cyclodextrin: Add 1 kg of β-cyclodextrin and 0.18 kg of 4-vinylphenol to 14 kg of dimethylformamide, stir to dissolve, then add 0.33 kg of triphenylphosphine and 0.27 kg of diisopropyl azodicarboxylate, react at 37 ° C for 6 hours, and remove the solvent by distillation under reduced pressure. Add 9.5 kg of dichloromethane to the obtained residue and dissolve it, then filter it, extract the obtained filtrate with 9.5 kg of water for 4 times, combine the organic layers, and finally remove the solvent by distillation under reduced pressure to obtain terminal olefin cyclodextrin.

[0029] Preparation of terminal alkenyl benzimidazole: 1 kg of 2-hydroxymethylbenzimidazole and 0.95 kg of 4-vinylphenol were added to 14 kg of dimethylformamide, stirred to dissolve, then 2.6 kg of triphenylphosphine and 1.9 kg of diisopropyl azodicarboxylate were added, and the mixture was reacted at 35 °C for 6 h. The solvent was removed by distillation under reduced pressure, and the residue was dissolved by adding 9 kg of dichloromethane and then filtered. The filtrate was extracted 5 times with 8 kg of water, and the organic layers were combined. Finally, the solvent was removed by distillation under reduced pressure to obtain terminal alkenylbenzimidazole.

[0030] Preparation of easily regenerable iron oxide desulfurizer: 4 kg of terminal alkenyl benzimidazole, 18 kg of terminal alkenyl cyclodextrin and 0.18 kg of azobisisobutyronitrile were added to 45 kg of toluene, heated to 80°C for reaction for 13 hours, and after the reaction was completed, the solvent was removed by distillation under reduced pressure, and the obtained solid was washed with acetone for 5 times and dried to obtain a polyethylene derivative; Add 7kg of ferric chloride to 100kg of water, stir to dissolve, then add 1.9kg of polyethylene derivative, stir for 4.5h, filter, wash, dry at 100℃ for 9h, and then calcine at 340℃ for 2.5h under nitrogen protection to obtain an easily regenerated iron oxide desulfurizer.

[0031] Example 5 Preparation of terminal olefin cyclodextrin: Add 1kg of β-cyclodextrin and 0.2kg of 4-vinylphenol to 15kg of dimethylformamide, stir to dissolve, then add 0.35kg of triphenylphosphine and 0.3kg of diisopropyl azodicarboxylate, react at 40°C for 5h, remove the solvent by distillation under reduced pressure, add 10kg of dichloromethane to the residue to dissolve and filter, extract the filtrate with 10kg of water for 5 times, combine the organic layers, and finally remove the solvent by distillation under reduced pressure to obtain terminal olefin cyclodextrin.

[0032] Preparation of terminal alkenyl benzimidazole: 1 kg of 2-hydroxymethylbenzimidazole and 1 kg of 4-vinylphenol were added to 15 kg of dimethylformamide, stirred to dissolve, then 2.8 kg of triphenylphosphine and 2 kg of diisopropyl azodicarboxylate were added, and the mixture was reacted at 40°C for 5 hours. The solvent was removed by distillation under reduced pressure, and the residue was dissolved in 10 kg of dichloromethane and filtered. The filtrate was extracted 4 times with 10 kg of water, and the organic layers were combined. Finally, the solvent was removed by distillation under reduced pressure to obtain terminal alkenylbenzimidazole.

[0033] Preparation of easily regenerable iron oxide desulfurizer: 5 kg of terminal alkenyl benzimidazole, 20 kg of terminal alkenyl cyclodextrin and 0.2 kg of azobisisobutyronitrile were added to 50 kg of toluene, heated to 90°C for reaction for 10 hours, and after the reaction was completed, the solvent was removed by distillation under reduced pressure, and the obtained solid was washed with acetone for 5 times and dried to obtain a polyethylene derivative; Add 8 kg of ferric sulfate into 100 kg of water, stir to dissolve, then add 2 kg of polyethylene derivative, stir for 5 hours, filter, wash, dry at 100 ° C for 10 hours, and then calcine at 350 ° C for 2 hours under nitrogen protection to obtain an easily regenerated iron oxide desulfurizer.

[0034] Example 6 Preparation of terminal olefin cyclodextrin: Add 1kg of β-cyclodextrin and 0.15kg of 4-vinylphenol to 13kg of dimethylformamide, stir to dissolve, then add 0.25kg of triphenylphosphine and 0.3kg of diisopropyl azodicarboxylate, react at 40°C for 10h, remove the solvent by distillation under reduced pressure, add 8kg of dichloromethane to the obtained residue to dissolve and filter, extract the obtained filtrate with 10kg of water for 5 times, combine the organic layers, and finally remove the solvent by distillation under reduced pressure to obtain terminal olefin cyclodextrin.

[0035] Preparation of terminal alkenyl benzimidazole: 1 kg of 2-hydroxymethylbenzimidazole and 0.8 kg of 4-vinylphenol were added to 12 kg of dimethylformamide, stirred to dissolve, then 2.8 kg of triphenylphosphine and 1.4 kg of diisopropyl azodicarboxylate were added, and the mixture was reacted at 40°C for 10 hours. The solvent was removed by distillation under reduced pressure, and the residue was dissolved by adding 8 kg of dichloromethane and then filtered. The filtrate was extracted 5 times with 5 kg of water, and the organic layers were combined. Finally, the solvent was removed by distillation under reduced pressure to obtain terminal alkenylbenzimidazole.

[0036] Preparation of easily regenerable iron oxide desulfurizer: 1 kg of terminal alkenyl benzimidazole, 15 kg of terminal alkenyl cyclodextrin and 0.1 kg of azobisisobutyronitrile were added to 40 kg of toluene, heated to 90°C for reaction for 20 hours, and after the reaction was completed, the solvent was removed by distillation under reduced pressure, and the obtained solid was washed with acetone for 5 times and dried to obtain a polyethylene derivative; Add 5 kg of ferric chloride into 100 kg of water, stir to dissolve, then add 1.8 kg of polyethylene derivative, stir for 4 hours, filter, wash, dry at 100 ° C for 8 hours, and then calcine at 330 ° C for 2.5 hours under nitrogen protection to obtain an easily regenerated iron oxide desulfurizer.

[0037] The easily regenerable iron oxide desulfurizers prepared in Examples 1 to 6 were respectively subjected to sulfur capacity determination according to the method provided in HG / T 5759-2020. The comparative example was an iron oxide desulfurizer purchased from Henan Huakang Activated Carbon Co., Ltd., and the test results are shown in Table 1.

[0038] Table 1 Determination results of sulfur capacity of desulfurizer

[0039] It can be seen from the results in Table 1 that the easily regenerated iron oxide desulfurizer prepared by the present invention has stronger adsorption performance and greater sulfur capacity than the comparative example because the polyethylene derivatives of benzimidazole and cyclodextrin are coated on the surface.

[0040] The easily regenerated iron oxide desulfurizer prepared in Examples 1 to 6 and the iron oxide desulfurizer of the comparative example were subjected to desulfurization detection in a micro fixed bed reactor. The size of the reactor was Φ10mm*12mm*300mm, the loading amount of the desulfurizer was 0.5g, and the upper and lower ends of the reactor were filled with quartz sand. An H2S and nitrogen mixer was used as a simulated raw gas, wherein the H2S content was 20mg / L, and the H2S not removed by the desulfurizer was absorbed by the tail gas absorption liquid. The H2S in the absorption liquid was detected every 5 minutes using the iodine method. When the purified gas concentration was 10% of the H2S gas concentration in the simulated raw gas, the desulfurizer was considered to have completely penetrated, the experiment was stopped, and its penetration time was recorded. The desulfurization rate was calculated based on the sulfur content in the absorption liquid after the adsorption was completed, and the calculation formula was:

[0041] Where, η is the desulfurization rate of the desulfurizer (%), V is the total gas volume (L), W is H2Sis the H2S content in the sample gas (mg / L), C1 is the concentration of the I2 standard solution (mol / L), V1 is the volume of the added I2 standard solution (mL), C2 is the concentration of the Na2S2O3 standard solution (mol / L), V2 is the volume of the Na2S2O3 standard solution consumed during titration (mL), and 34 is the molar mass of H2S (g / mol). The results of the desulfurization rate and breakthrough time test are shown in Table 2.

[0042] Table 2 Desulfurization rate test results of desulfurizer

[0043] It can be seen from the results in Table 2 that the easily regenerated iron oxide desulfurizer prepared by the present invention has a stronger adsorption capacity for hydrogen sulfide, a higher desulfurization rate, a longer penetration time, and a very good desulfurization effect than the comparative example.

[0044] After the desulfurization reaction, the desulfurizer was dried, and then introduced into a mixture of hydrogen and nitrogen with a hydrogen volume concentration of 2% for heat treatment at a temperature of 300°C for 30 minutes. Then, the mixture was introduced into a mixture of oxygen and nitrogen with an oxygen volume concentration of 2% for heat treatment at a temperature of 350°C for 3 hours to obtain a regenerated desulfurizer. The regenerated desulfurizer was further subjected to desulfurization reaction. The desulfurization detection conditions were the same as above. After the desulfurization reaction was completed, it was regenerated again under the same regeneration conditions. This cycle was repeated 7 times. The sulfur capacity and desulfurization rate of the desulfurizer were detected. The detection results are shown in Table 3.

[0045] Table 3 Desulfurization agent regeneration test results

[0046] It can be seen from the results in Table 3 that the easily regenerated iron oxide desulfurizer prepared by the present invention still has a high sulfur capacity and desulfurization efficiency after 7 cycles of regeneration, indicating that the desulfurizer prepared by the present invention is easy to regenerate and can be used for the removal of hydrogen sulfide.

[0047] Although the above describes the specific implementation methods of the present invention, it does not limit the scope of protection of the present invention. Based on the technical solution of the present invention, various modifications or variations that can be made by those skilled in the art without creative work are still within the scope of protection of the present invention.

Claims

1. An easily regenerable iron oxide desulfurizer, characterized in that: The polyethylene derivative is prepared by polymerizing terminal alkenyl cyclodextrin and terminal alkenyl benzimidazole, and then mixed with soluble iron salt to prepare the polyethylene derivative.

2. An easily regenerable iron oxide desulfurizer as claimed in claim 1, characterized in that: The terminal olefin cyclodextrin is prepared according to the following method: Add β-cyclodextrin and 4-vinylphenol to dimethylformamide, stir to dissolve, add triphenylphosphine and diisopropyl azodicarboxylate, react at 25-40°C for 5-10 hours, remove the solvent by distillation under reduced pressure, add dichloromethane to dissolve the obtained residue and filter it, extract the obtained filtrate with water for 3-5 times, combine the organic layers, and finally remove the solvent by distillation under reduced pressure to obtain terminal olefin cyclodextrin.

3. An easily regenerable iron oxide desulfurizer as claimed in claim 2, characterized in that: The mass ratio of the beta-cyclodextrin, 4-vinylphenol, dimethylformamide, triphenylphosphine, diisopropyl azodicarboxylate, dichloromethane and water is 1: 0.1-0.2: 10-15: 0.25-0.35: 0.2-0.3: 8-10: 8-10.

4. An easily regenerable iron oxide desulfurizer as claimed in claim 1, characterized in that: The terminal alkenyl benzimidazole is prepared according to the following method: Add 2-hydroxymethylbenzimidazole and 4-vinylphenol to dimethylformamide, stir and dissolve, then add triphenylphosphine and diisopropyl azodicarboxylate, react at 25-40°C for 5-10 hours, remove the solvent by distillation under reduced pressure, add dichloromethane to dissolve the obtained residue and filter it, extract the obtained filtrate with water for 3-5 times, combine the organic layers, and finally remove the solvent by distillation under reduced pressure to obtain terminal alkenylbenzimidazole.

5. An easily regenerable iron oxide desulfurizer as claimed in claim 4, characterized in that: The mass ratio of the 2-hydroxymethylbenzimidazole, 4-vinylphenol, dimethylformamide, triphenylphosphine, diisopropyl azodicarboxylate, dichloromethane and water is 1:0.8-1:10-15:2-2.8:1.4-2:5-10:5-10.

6. A method for preparing the easily regenerable iron oxide desulfurizer as claimed in claim 1, characterized in that: The following steps are involved: 1) Add terminal alkenyl benzimidazole, terminal alkenyl cyclodextrin and azobisisobutyronitrile to toluene, heat to 50-90°C for reaction for 10-20 hours, and after the reaction is completed, remove the solvent by vacuum distillation, wash the obtained solid with acetone for 3-5 times, and dry to obtain a polyethylene derivative; 2) Add iron salt into water, stir to dissolve, then add the polyethylene derivative obtained in step 1), stir for 3-5 hours, filter, wash, dry at 100° C. for 5-10 hours, and then calcine at 300-350° C. for 2-4 hours under nitrogen protection to obtain an easily regenerable iron oxide desulfurizer.

7. A method for preparing the easily regenerable iron oxide desulfurizer as claimed in claim 6, characterized in that: The mass ratio of the terminal alkenyl benzimidazole, the terminal alkenyl cyclodextrin, azobisisobutyronitrile and toluene in step 1) is 1-5:5-20:0.03-0.2:15-50.

8. A method for preparing the easily regenerable iron oxide desulfurizer as claimed in claim 6, characterized in that: The mass ratio of the iron salt, water and polyethylene derivative in step 2) is 20-80:1000:15-20.

9. A method for preparing the easily regenerable iron oxide desulfurizer as claimed in claim 6, characterized in that: The mass ratio of the iron salt, water and polyethylene derivative in step 2) is 20-80:1000:15-20; the iron salt in step 2) is ferric chloride or ferric sulfate.

10. Use of the easily regenerable iron oxide desulfurizer as claimed in claim 1 in removing hydrogen sulfide.

Images