An easily regenerable iron oxide desulfurizer and its preparation method

Abstract

The present invention discloses a regenerable iron oxide desulfurizer and a preparation method thereof, belonging 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 with hydrogen sulfide is improved, and the deposition of iron sulfide on the surface of the desulfurizer is reduced, thereby avoiding the formation of ferrous sulfide and improving the regeneration ability of the desulfurizer; due to the wrapping of the polymer, the chemical stability and thermal stability of the desulfurizer are increased, so that the desulfurizer maintains stable performance during the use process and the regeneration process. The desulfurizer prepared by the present invention has strong adsorption capacity for hydrogen sulfide, high sulfur capacity, and is easy to regenerate, and can be used for the removal of hydrogen sulfide.

Description

Technical Field

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

[0002] The iron oxide desulfurizer is a highly efficient gas purifying agent processed with iron oxide as the main active component and adding 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] During the process of removing hydrogen sulfide by the iron oxide desulfurizer, iron sulfide or ferrous sulfide is continuously generated. In the presence of oxygen, iron sulfide can be oxidized and regenerated into iron oxide, while the formation of ferrous sulfide will reduce the activity of the iron oxide desulfurizer, thus affecting its desulfurization effect; in addition, ferrous sulfide is not easily regenerated, which further affects the regeneration ability of the desulfurizer. Therefore, developing a new type of iron oxide desulfurizer to avoid the formation of ferrous disulfide is of great significance for improving the desulfurization performance of the desulfurizer, as well as its stability and regeneration ability. 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] To achieve the above purpose, the present invention is realized through the following technical solutions:

[0006] An easily regenerable iron oxide desulfurizer is prepared by polymerizing terminal alkenyl cyclodextrin and terminal alkenyl benzimidazole to obtain a polyethylene derivative, and then mixing it with a soluble iron salt.

[0007] The terminal alkenyl cyclodextrin is prepared according to the following method:

[0008] β - cyclodextrin and 4 - vinylphenol are added to dimethylformamide, stirred and dissolved, then triphenylphosphine and diisopropyl azodicarboxylate are added, and the reaction is carried out at 25 - 40 °C for 5 - 10 h. The solvent is removed by vacuum distillation. The obtained residue is dissolved in dichloromethane and filtered by suction. The obtained filtrate is extracted with water 3 - 5 times, the organic layers are combined, and finally the solvent is removed by vacuum distillation to obtain terminal alkenyl cyclodextrin.

[0009] The mass ratio of the β - 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.

[0010] The terminal alkenyl benzimidazole is prepared according to the following method:

[0011] 2-Hydroxymethylbenzimidazole and 4-vinylphenol were added to dimethylformamide. After stirring and dissolving, triphenylphosphine and diisopropyl azodicarboxylate were added. The reaction was carried out at 25 - 40 °C for 5 - 10 h. The solvent was removed by distillation under reduced pressure. The obtained residue was dissolved in dichloromethane and then filtered. The filtrate was extracted with water 3 - 5 times. The organic layers were combined and finally the solvent was removed by distillation under reduced pressure to obtain terminal alkenyl benzimidazole.

[0012] 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.

[0013] The preparation method of the easily regenerable iron oxide desulfurizer described above includes the following steps:

[0014] 1) Terminal alkenyl benzimidazole, terminal alkenyl cyclodextrin and 2,2'-azobis(isobutyronitrile) were added to toluene. The mixture was heated to 50 - 90 °C and reacted for 10 - 20 h. After the reaction ended, the solvent was removed by distillation under reduced pressure. The obtained solid was washed with acetone 3 - 5 times and dried to obtain a polyethylene derivative.

[0015] 2) Iron salt was added to water. After stirring and dissolving, the polyethylene derivative prepared in step 1) was added thereto. After stirring for 3 - 5 h, filtration, washing were carried out, and then drying was carried out at 100 °C for 5 - 10 h. Then, under nitrogen protection, calcination was carried out at 300 - 350 °C for 2 - 4 h to obtain the easily regenerable iron oxide desulfurizer.

[0016] The mass ratio of the terminal alkenyl benzimidazole, terminal alkenyl cyclodextrin, 2,2'-azobis(isobutyronitrile) and toluene in step 1) is 1 - 5:5 - 20:0.03 - 0.2:15 - 50.

[0017] The mass ratio of the iron salt, water and polyethylene derivative in step 2) is 20 - 80:1000:15 - 20.

[0018] The iron salt described in step 2) is ferric chloride or ferric sulfate.

[0019] The present invention also includes the application of the easily regenerable iron oxide desulfurizer in removing hydrogen sulfide.

[0020] The present invention has the following advantages compared with the prior art:

[0021] The easily regenerable iron oxide desulfurizer of the present invention is prepared by coating the surface of iron oxide with a polyethylene derivative of benzimidazole and cyclodextrin. The introduction of benzimidazole improves the reaction selectivity of the desulfurizer with hydrogen sulfide on the one hand, reduces the deposition of iron sulfide on the surface of the desulfurizer, thus avoiding the formation of iron sulfide, and improves the regeneration ability of the desulfurizer; on the other hand, it can improve the thermal stability of the polyethylene derivative; due to its hierarchical pore structure and high specific surface area, cyclodextrin significantly improves the adsorption capacity for hydrogen sulfide, 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 compound with hydrogen sulfide, which helps to stably fix hydrogen sulfide in the desulfurizer, and promotes the dissociation of hydrogen sulfide by heating, further improving its regeneration performance.

[0022] The easily regenerable iron oxide desulfurizer of the present invention is prepared by coating the surface of iron oxide with a polyethylene derivative. On the one hand, the polymer forms a protective film on the surface of the iron oxide particles, reducing the agglomeration between the iron oxide particles, helping to maintain the specific surface area of the iron oxide, and improving 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 desulfurizer maintains stable performance during use and regeneration.

[0023] The desulfurizer prepared by the present invention has strong adsorption capacity for hydrogen sulfide, high sulfur capacity, and is easy to regenerate, and can be used for the removal of hydrogen sulfide. Detailed implementation mode

[0024] To better understand the technical solution of the present invention, the above content of the present invention will be further described in detail below through specific implementation modes in the form of examples, but this should not be understood as limiting the scope of the above-mentioned subject matter of the present invention to the following examples. All technologies implemented based on the above content of the present invention belong to the scope of the present invention.

[0025] Example 1 Preparation of alkenyl cyclodextrin:

[0026] 1 kg of β-cyclodextrin and 0.1 kg of 4-vinylphenol are added to 10 kg of dimethylformamide. After stirring and dissolving, 0.25 kg of triphenylphosphine and 0.2 kg of diisopropyl azodicarboxylate are added, and the reaction is carried out at 25 °C for 10 h. The solvent is removed by vacuum distillation. The obtained residue is dissolved in 8 kg of dichloromethane and then filtered. The obtained filtrate is extracted 3 times with 8 kg of water, the organic layers are combined, and finally the solvent is removed by vacuum distillation to obtain alkenyl cyclodextrin.

[0027] Preparation of alkenyl benzimidazole:

[0028] 1 kg of 2-(hydroxymethyl)benzimidazole and 0.8 kg of 4-vinylphenol were added to 10 kg of dimethylformamide. After stirring and dissolving, 2 kg of triphenylphosphine and 1.4 kg of diisopropyl azodicarboxylate were added. The reaction was carried out at 25 °C for 10 h. The solvent was removed by distillation under reduced pressure. The resulting residue was dissolved in 5 kg of dichloromethane and filtered. The filtrate was extracted 3 times with 5 kg of water. The organic layers were combined and finally the solvent was removed by distillation under reduced pressure to obtain terminal alkenyl benzimidazole. 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).

[0029] Preparation of easily regenerable iron oxide desulfurizer:

[0030] 1 kg of terminal alkenyl benzimidazole, 5 kg of terminal alkenyl cyclodextrin and 0.03 kg of 2,2'-azobis(2-methylpropionitrile) were added to 15 kg of toluene. The mixture was heated to 50 °C and reacted for 20 h. After the reaction, the solvent was removed by distillation under reduced pressure. The resulting solid was washed 3 times with acetone and dried to obtain a polyethylene derivative.

[0031] 2 kg of ferric chloride was added to 100 kg of water. After stirring and dissolving, 1.5 kg of the polyethylene derivative was added thereto. After stirring for 3 h, the mixture was filtered, washed and dried at 100 °C for 5 h. Then, it was calcined at 300 °C for 4 h under nitrogen protection to obtain an easily regenerable iron oxide desulfurizer.

[0032] Example 2 Preparation of terminal alkenyl cyclodextrin:

[0033] 1 kg of β-cyclodextrin and 0.12 kg of 4-vinylphenol were added to 11 kg of dimethylformamide. After stirring and dissolving, 0.28 kg of triphenylphosphine and 0.21 kg of diisopropyl azodicarboxylate were added. The reaction was carried out at 30 °C for 9 h. The solvent was removed by distillation under reduced pressure. The resulting residue was dissolved in 8.5 kg of dichloromethane and filtered. The filtrate was extracted 5 times with 8.5 kg of water. The organic layers were combined and finally the solvent was removed by distillation under reduced pressure to obtain terminal alkenyl cyclodextrin.

[0034] Preparation of terminal alkenyl benzimidazole:

[0035] 1 kg of 2-(hydroxymethyl)benzimidazole and 0.85 kg of 4-vinylphenol were added to 11 kg of dimethylformamide. After stirring and dissolving, 2.2 kg of triphenylphosphine and 1.5 kg of diisopropyl azodicarboxylate were added, and the reaction was carried out at 26 °C for 9 h. The solvent was removed by distillation under reduced pressure. The obtained residue was dissolved in 6 kg of dichloromethane and then filtered by suction. The obtained filtrate was extracted 5 times with 6 kg of water. The organic layers were combined, and finally the solvent was removed by distillation under reduced pressure to obtain terminal alkenyl benzimidazole.

[0036] Preparation of easily regenerable iron oxide desulfurizer:

[0037] 2 kg of terminal alkenyl benzimidazole, 8 kg of terminal alkenyl cyclodextrin and 0.09 kg of 2,2'-azobis(2-methylpropionitrile) were added to 25 kg of toluene. The mixture was heated to 60 °C and reacted for 18 h. After the reaction was completed, the solvent was removed by distillation under reduced pressure. The obtained solid was washed 4 times with acetone and dried to obtain a polyethylene derivative.

[0038] 3 kg of ferric sulfate was added to 100 kg of water. After stirring and dissolving, 1.6 kg of the polyethylene derivative was added thereto. After stirring for 3.5 h, filtration and washing were carried out, and drying was carried out at 100 °C for 6 h. Then, calcination was carried out at 310 °C for 3.5 h under nitrogen protection to obtain an easily regenerable iron oxide desulfurizer.

[0039] Example 3 Preparation of terminal alkenyl cyclodextrin:

[0040] 1 kg of β-cyclodextrin and 0.15 kg of 4-vinylphenol were added to 13 kg of dimethylformamide. After stirring and dissolving, 0.3 kg of triphenylphosphine and 0.24 kg of diisopropyl azodicarboxylate were added, and the reaction was carried out at 35 °C for 8 h. The solvent was removed by distillation under reduced pressure. The obtained residue was dissolved in 9 kg of dichloromethane and then filtered by suction. The obtained filtrate was extracted 4 times with 9 kg of water. The organic layers were combined, and finally the solvent was removed by distillation under reduced pressure to obtain terminal alkenyl cyclodextrin.

[0041] Preparation of terminal alkenyl benzimidazole:

[0042] 1 kg of 2-(hydroxymethyl)benzimidazole and 0.9 kg of 4-vinylphenol were added to 12 kg of dimethylformamide. After stirring and dissolving, 2.4 kg of triphenylphosphine and 1.7 kg of diisopropyl azodicarboxylate were added, and the reaction was carried out at 30 °C for 8 h. The solvent was removed by distillation under reduced pressure. The obtained residue was dissolved in 7 kg of dichloromethane and then filtered by suction. The obtained filtrate was extracted 4 times with 7 kg of water. The organic layers were combined, and finally the solvent was removed by distillation under reduced pressure to obtain terminal alkenyl benzimidazole.

[0043] Preparation of easily regenerable iron oxide desulfurizer:

[0044] Add 3 kg of terminal alkenyl benzimidazole, 12 kg of terminal alkenyl cyclodextrin and 0.14 kg of azobisisobutyronitrile to 35 kg of toluene, heat to 70 °C and react for 15 h. After the reaction, remove the solvent by vacuum distillation. Wash the obtained solid with acetone 5 times and dry it to obtain a polyethylene derivative;

[0045] Add 5 kg of ferric sulfate to 100 kg of water, stir to dissolve it, then add 1.8 kg of the polyethylene derivative thereto, stir for 4 h, filter, wash, dry at 100 °C for 8 h, and then calcine at 330 °C for 3 h under nitrogen protection to obtain a regenerable iron oxide desulfurizer.

[0046] Example 4 Preparation of terminal alkenyl cyclodextrin:

[0047] Add 1 kg of β-cyclodextrin and 0.18 kg of 4-vinylphenol to 14 kg of dimethylformamide, stir to dissolve, add 0.33 kg of triphenylphosphine and 0.27 kg of diisopropyl azodicarboxylate, react at 37 °C for 6 h, remove the solvent by vacuum distillation. Dissolve the obtained residue in 9.5 kg of dichloromethane and filter by suction. Extract the obtained filtrate with 9.5 kg of water 4 times, combine the organic layers, and finally remove the solvent by vacuum distillation to obtain terminal alkenyl cyclodextrin.

[0048] Preparation of terminal alkenyl benzimidazole:

[0049] Add 1 kg of 2-hydroxymethylbenzimidazole and 0.95 kg of 4-vinylphenol to 14 kg of dimethylformamide, stir to dissolve, add 2.6 kg of triphenylphosphine and 1.9 kg of diisopropyl azodicarboxylate, react at 35 °C for 6 h, remove the solvent by vacuum distillation. Dissolve the obtained residue in 9 kg of dichloromethane and filter by suction. Extract the obtained filtrate with 8 kg of water 5 times, combine the organic layers, and finally remove the solvent by vacuum distillation to obtain terminal alkenyl benzimidazole.

[0050] Preparation of regenerable iron oxide desulfurizer:

[0051] Add 4 kg of terminal alkenyl benzimidazole, 18 kg of terminal alkenyl cyclodextrin and 0.18 kg of azobisisobutyronitrile to 45 kg of toluene, heat to 80 °C and react for 13 h. After the reaction, remove the solvent by vacuum distillation. Wash the obtained solid with acetone 5 times and dry it to obtain a polyethylene derivative;

[0052] Add 7 kg of ferric chloride to 100 kg of water, stir to dissolve it, then add 1.9 kg of the polyethylene derivative thereto, stir for 4.5 h, filter, wash, dry at 100 °C for 9 h, and then calcine at 340 °C for 2.5 h under nitrogen protection to obtain a regenerable iron oxide desulfurizer.

[0053] Example 5 Preparation of terminal alkenyl cyclodextrin:

[0054] 1 kg of β-cyclodextrin and 0.2 kg of 4-vinylphenol were added to 15 kg of dimethylformamide. After stirring and dissolving, 0.35 kg of triphenylphosphine and 0.3 kg of diisopropyl azodicarboxylate were added, and the reaction was carried out at 40 °C for 5 h. The solvent was removed by distillation under reduced pressure. The obtained residue was dissolved in 10 kg of dichloromethane and then filtered. The obtained filtrate was extracted 5 times with 10 kg of water. The organic layers were combined, and finally the solvent was removed by distillation under reduced pressure to obtain alkenyl-terminated cyclodextrin.

[0055] Preparation of alkenyl-terminated benzimidazole:

[0056] 1 kg of 2-(hydroxymethyl)benzimidazole and 1 kg of 4-vinylphenol were added to 15 kg of dimethylformamide. After stirring and dissolving, 2.8 kg of triphenylphosphine and 2 kg of diisopropyl azodicarboxylate were added, and the reaction was carried out at 40 °C for 5 h. The solvent was removed by distillation under reduced pressure. The obtained residue was dissolved in 10 kg of dichloromethane and then filtered. The obtained filtrate was extracted 4 times with 10 kg of water. The organic layers were combined, and finally the solvent was removed by distillation under reduced pressure to obtain alkenyl-terminated benzimidazole.

[0057] Preparation of easily regenerable iron oxide desulfurizer:

[0058] 5 kg of alkenyl-terminated benzimidazole, 20 kg of alkenyl-terminated cyclodextrin and 0.2 kg of 2,2'-azobis(2-methylpropionitrile) were added to 50 kg of toluene. The mixture was heated to 90 °C and reacted for 10 h. After the reaction, the solvent was removed by distillation under reduced pressure. The obtained solid was washed 5 times with acetone and dried to obtain a polyethylene derivative;

[0059] 8 kg of ferric sulfate was added to 100 kg of water. After stirring and dissolving, 2 kg of the polyethylene derivative was added thereto. After stirring for 5 h, it was filtered, washed, dried at 100 °C for 10 h, and then calcined at 350 °C for 2 h under nitrogen protection to obtain an easily regenerable iron oxide desulfurizer.

[0060] Example 6 Preparation of alkenyl-terminated cyclodextrin:

[0061] 1 kg of β-cyclodextrin and 0.15 kg of 4-vinylphenol were added to 13 kg of dimethylformamide. After stirring and dissolving, 0.25 kg of triphenylphosphine and 0.3 kg of diisopropyl azodicarboxylate were added, and the reaction was carried out at 40 °C for 10 h. The solvent was removed by distillation under reduced pressure. The obtained residue was dissolved in 8 kg of dichloromethane and then filtered. The obtained filtrate was extracted 5 times with 10 kg of water. The organic layers were combined, and finally the solvent was removed by distillation under reduced pressure to obtain alkenyl-terminated cyclodextrin.

[0062] Preparation of alkenyl-terminated benzimidazole:

[0063] 1 kg of 2-(hydroxymethyl)benzimidazole and 0.8 kg of 4-vinylphenol were added to 12 kg of dimethylformamide. After stirring and dissolving, 2.8 kg of triphenylphosphine and 1.4 kg of diisopropyl azodicarboxylate were added, and the reaction was carried out at 40 °C for 10 h. The solvent was removed by vacuum distillation. The obtained residue was dissolved in 8 kg of dichloromethane and then filtered. The obtained filtrate was extracted 5 times with 5 kg of water. The organic layers were combined, and finally the solvent was removed by vacuum distillation to obtain terminal alkenyl benzimidazole.

[0064] Preparation of easily regenerable iron oxide desulfurizer:

[0065] 1 kg of terminal alkenyl benzimidazole, 15 kg of terminal alkenyl cyclodextrin and 0.1 kg of 2,2'-azobis(2-methylpropionitrile) were added to 40 kg of toluene. The mixture was heated to 90 °C and reacted for 20 h. After the reaction, the solvent was removed by vacuum distillation. The obtained solid was washed 5 times with acetone and then dried to obtain a polyethylene derivative.

[0066] 5 kg of ferric chloride was added to 100 kg of water. After stirring and dissolving, 1.8 kg of the polyethylene derivative was added thereto. After stirring for 4 h, the mixture was filtered, washed, dried at 100 °C for 8 h, and then calcined at 330 °C for 2.5 h under nitrogen protection to obtain an easily regenerable iron oxide desulfurizer.

[0067] The easily regenerable iron oxide desulfurizers prepared in Examples 1-6 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. The test results are shown in Table 1.

[0068] Table 1 Sulfur capacity determination results of desulfurizers

[0069]

[0070] It can be seen from the results in Table 1 that the easily regenerable iron oxide desulfurizer prepared by the present invention has stronger adsorption performance because its surface is coated with a polyethylene derivative of benzimidazole and cyclodextrin, and has a larger sulfur capacity compared with the comparative example.

[0071] The easily regenerable iron oxide desulfurizers prepared in Examples 1-6 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 Φ10 mm * 12 mm * 300 mm, the loading amount of the desulfurizer was 0.5 g, and quartz sand was filled at the upper and lower ends of the reactor; H 2 S and nitrogen mixer was used as the simulated raw material gas, in which the content of H 2 S was 20 mg / L. The unremoved H 2 S by the desulfurizer was absorbed by the tail gas absorption liquid, and the H 2 S in the absorption liquid was detected by the iodine method every 5 min. When the concentration of the purified gas was the same as that of H in the simulated raw material gas2 When the concentration of SO₂ gas reaches 10%, it is regarded that the desulfurizer is completely penetrated, and the experiment is stopped, and the penetration time is recorded. The desulfurization rate is calculated according to the sulfur content in the absorption liquid after the adsorption ends, and its calculation formula is

[0072]

[0073] In the formula, η is the desulfurization rate of the desulfurizer (%), V is the total gas volume (L), W H2S is the H₂S content (mg / L) in the sample gas, C 2 is the concentration (mol / L) of the I₂ standard solution, V 1 is the volume (mL) of the I₂ standard solution added, C 2 is the concentration (mol / L) of the Na₂S₂O₃ standard solution, V 1 is the volume (mL) of the Na₂S₂O₃ standard solution consumed during titration, 34 is the molar mass of H₂S (g / mol). The detection results of the desulfurization rate and penetration time are shown in Table 2 2 is the concentration (mol / L) of the I₂ standard solution, V 2 is the concentration (mol / L) of the Na₂S₂O₃ standard solution, V 2 is the volume (mL) of the Na₂S₂O₃ standard solution consumed during titration, 34 is the molar mass of H₂S (g / mol). The detection results of the desulfurization rate and penetration time are shown in Table 2 2 is the volume (mL) of the Na₂S₂O₃ standard solution consumed during titration, 34 is the molar mass of H₂S (g / mol). The detection results of the desulfurization rate and penetration time are shown in Table 2 3 is the volume (mL) of the Na₂S₂O₃ standard solution consumed during titration, 34 is the molar mass of H₂S (g / mol). The detection results of the desulfurization rate and penetration time are shown in Table 2 2 is the volume (mL) of the Na₂S₂O₃ standard solution consumed during titration, 34 is the molar mass of H₂S (g / mol). The detection results of the desulfurization rate and penetration time are shown in Table 2 2 is the volume (mL) of the Na₂S₂O₃ standard solution consumed during titration, 34 is the molar mass of H₂S (g / mol). The detection results of the desulfurization rate and penetration time are shown in Table 2 2 is the volume (mL) of the Na₂S₂O₃ standard solution consumed during titration, 34 is the molar mass of H₂S (g / mol). The detection results of the desulfurization rate and penetration time are shown in Table 2 3 is the volume (mL) of the Na₂S₂O₃ standard solution consumed during titration, 34 is the molar mass of H₂S (g / mol). The detection results of the desulfurization rate and penetration time are shown in Table 2 2 is the molar mass of H₂S (g / mol). The detection results of the desulfurization rate and penetration time are shown in Table 2

[0074] Table 2 Detection results of the desulfurization rate of the desulfurizer

[0075]

[0076] As can be seen from the results in Table 2, the regenerable iron oxide desulfurizer prepared by the present invention has a stronger adsorption capacity for hydrogen sulfide, a higher desulfurization rate, and a longer penetration time, and has a good desulfurization effect

[0077] After drying the desulfurizer after the above desulfurization reaction, it is introduced into a mixture of hydrogen and nitrogen with a hydrogen volume concentration of 2% for heat treatment at a heat treatment temperature of 300 °C for a treatment time of 30 min, and then introduced into a mixture of oxygen and nitrogen with an oxygen volume concentration of 2% for heat treatment at a treatment temperature of 350 °C for a treatment time of 3 h to obtain a regenerated desulfurizer. The regenerated desulfurizer is continued to carry out the desulfurization reaction, and the desulfurization detection conditions are the same as above. After the desulfurization reaction ends, it is regenerated again under the same regeneration conditions. After repeating this cycle 7 times, the sulfur capacity and desulfurization rate of the desulfurizer are detected, and the detection results are shown in Table 3

[0078] Table 3 Detection results of the cyclic regeneration of the desulfurizer

[0079]

[0080] As can be seen from the results in Table 3, the easily regenerable 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.

[0081] Although the specific implementation manners of the present invention are described above, they do not limit the protection scope of the present invention. Based on the technical solutions of the present invention, various modifications or deformations that can be made by those skilled in the art without creative efforts are still within the protection scope 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; The terminal olefin cyclodextrin is prepared according to the following method: β-cyclodextrin and 4-vinylphenol are added to dimethylformamide, stirred and dissolved, triphenylphosphine and diisopropyl azodicarboxylate are added, reacted at 25-40°C for 5-10 hours, and the solvent is removed by vacuum distillation. The obtained residue is dissolved by adding dichloromethane and then filtered. The obtained filtrate is extracted with water for 3-5 times, the organic layers are combined, and the solvent is removed by vacuum distillation to obtain terminal olefin cyclodextrin; 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.

2. An easily regenerable iron oxide desulfurizer as claimed in claim 1, 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.

3. An easily regenerable iron oxide desulfurizer as claimed in claim 1, 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.

4. 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.

5. A method for preparing the easily regenerable iron oxide desulfurizer as claimed in claim 4, characterized in that: The mass ratio of the terminal alkenyl benzimidazole, terminal alkenyl cyclodextrin, azobisisobutyronitrile and toluene in step 1) is 1-5:5-20:0.03-0.2:15-50.

6. A method for preparing the easily regenerable iron oxide desulfurizer as claimed in claim 4, characterized in that: The mass ratio of the iron salt, water and polyethylene derivative in step 2) is 20-80:1000:15-20.

7. A method for preparing the easily regenerable iron oxide desulfurizer as claimed in claim 4, 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.

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

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