Preparation method and regeneration process of renewable iron oxide desulfurizer

Abstract

The application discloses a preparation method and a regeneration process of a renewable iron oxide desulfurizer, and belongs to the technical field of coal chemical desulfurizer preparation. The preparation method comprises the following steps: carrying out a hydrothermal reaction on a silicon dioxide nanofiber aerogel carrier in an iron nitrate solution to obtain a desulfurizer precursor; and carrying out an oxidation treatment on the desulfurizer precursor in a microwave field to obtain the renewable iron oxide desulfurizer. The desulfurizer preparation process route is simple and easy to implement, the desulfurizer regeneration process is high in efficiency and excellent in desulfurizer regeneration performance, and can meet the performance requirements of desulfurizer industrialization; on the other hand, the flexible and high-porosity fiber material is used as the carrier to construct the multi-level micro-pore structure of the desulfurizer, so that the adsorption capacity and desulfurization reaction activity of the desulfurizer can be improved.

Description

Technical Field

[0001] This invention relates to the field of coal chemical desulfurization agent preparation technology, and in particular to a method for preparing and regenerating a regenerable iron oxide desulfurization agent. Background Technology

[0002] As one of the three major fossil fuels, coal's fundamental energy importance in economic development is unshakeable. However, the various environmental problems caused by the direct combustion of coal cannot be ignored. Integrated gasification combined cycle (IGCC) power generation technology, based on the clean and efficient utilization of coal, has been widely adopted in many countries and regions. Coal gas, as the power and feedstock source in IGCC technology, contains a large amount of sulfides, more than 90% of which is hydrogen sulfide (H2S). Hydrogen sulfide not only corrodes industrial equipment and poisons catalysts, but also poses a threat to the ecological environment and human health when released into the atmosphere. Therefore, hydrogen sulfide must be completely removed from coal gas before use.

[0003] Dry desulfurization utilizes metal oxides in solid-phase desulfurizing agents to convert and remove H2S through chemical reactions. This method has advantages such as simple process flow, no wastewater or waste acid treatment issues, low energy consumption, low equipment corrosivity, and low cost. Studies have shown that desulfurizing agents with zinc oxide as the active component have higher desulfurization precision and efficiency than other oxide desulfurizing agents. However, zinc oxide is prone to volatilization during high-temperature regeneration, leading to loss of active components and severe performance degradation. Copper oxide has a strong affinity and adsorption capacity for hydrogen sulfide. Some researchers have found that copper oxide desulfurizing agents have high desulfurization precision, are less affected by temperature, and have good regeneration performance.

[0004] However, current dry desulfurization technologies suffer from drawbacks such as large desulfurizing agent loading, frequent agent replacement, difficulty in regenerating spent desulfurizing agents, and challenges in solid waste treatment. While existing desulfurizing agent preparation methods and regeneration processes are relatively mature, they still suffer from drawbacks such as high regeneration temperatures, difficulty in regeneration leading to short service life, and high operating costs. Therefore, existing desulfurizing agents cannot meet the requirements of practical industrial applications, and developing novel, highly efficient, and regenerable solid desulfurizing agents with high desulfurization efficiency, speed, and selectivity remains one of the goals of gas desulfurization technology. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing and regenerating a regenerable iron oxide desulfurizer, in order to solve the problems of low utilization rate of active components and poor sulfidation-regeneration performance of the desulfurizer during the reaction process, and ultimately improve the sulfidation and recycling performance of the desulfurizer.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] One of the technical solutions of the present invention is a method for preparing a renewable iron oxide desulfurizer, comprising the following steps: performing a hydrothermal reaction of a silica nanofiber aerogel carrier in an iron nitrate solution to obtain a desulfurizer precursor; and subjecting the desulfurizer precursor to oxidation treatment under a microwave field to obtain the renewable iron oxide desulfurizer.

[0008] Furthermore, the porosity of the silica nanofiber aerogel carrier is 95-99.99%, and the diameter of the silica nanofibers is 100-1000 nm.

[0009] Furthermore, the concentration of the ferric nitrate solution is 0.1-0.4 mol / L.

[0010] Furthermore, the hydrothermal reaction is carried out at a temperature of 80-110°C for a duration of 1-4 hours.

[0011] Furthermore, in the hydrothermal reaction process, the ratio of silica nanofiber aerogel carrier to ferric nitrate solution is 0.4 g: 100 mL. The active component, iron oxide (Fe2O3), is generated during the hydrothermal reaction.

[0012] Furthermore, the microwave field has a microwave condition of 1500W.

[0013] Furthermore, the specific parameters of the oxidation treatment include: an oxygen concentration of 1-4 vol%, a calcination temperature of 200-350℃, and a calcination time of 1 h.

[0014] The second technical solution of the present invention: a renewable iron oxide desulfurizer prepared by the above preparation method.

[0015] Furthermore, the renewable iron oxide desulfurizer uses silica nanofiber aerogel as a carrier, and the carrier is loaded with the active component iron oxide, which can be called iron oxide / silica nanofiber aerogel composite desulfurizer.

[0016] Furthermore, the content of iron oxide in the renewable iron oxide desulfurizer is 50-81 wt%.

[0017] The third technical solution of the present invention: a method for regenerating the above-mentioned regenerable iron oxide desulfurizer, comprising the following steps: soaking the regenerable iron oxide desulfurizer after the desulfurization reaction in KF solution and K3P solution for 12 hours each, drying it, and then placing it under a microwave field and sequentially passing hydrogen, argon and oxygen through it for heat treatment to obtain the regenerated desulfurizer.

[0018] Furthermore, the regenerable iron oxide desulfurizer after the desulfurization reaction is specifically the regenerable iron oxide desulfurizer after absorbing H2S to saturation, that is, the desulfurization reaction is carried out until the regenerable iron oxide desulfurizer is saturated.

[0019] Furthermore, the concentration of the KF solution is 1-4 mmol / L, and the concentration of the K3P solution is 1-4 mmol / L.

[0020] Furthermore, the concentration of hydrogen is 2-8 vol%, the concentration of oxygen is 1-4 vol%, and the equilibrium gas when hydrogen and oxygen are introduced is nitrogen. That is, when hydrogen is introduced, a mixture of hydrogen and nitrogen is introduced, and when oxygen is introduced, a mixture of oxygen and nitrogen is introduced.

[0021] Furthermore, the argon gas is pure argon gas.

[0022] Furthermore, the microwave field has a microwave condition of 1000W.

[0023] Furthermore, the heat treatment temperature for hydrogen gas is 500℃ and the heat treatment time is 30 min; the heat treatment temperature for argon gas is 500℃ and the heat treatment time is 30 min; and the heat treatment temperature for oxygen gas is 420℃ and the heat treatment time is 2 h.

[0024] The first two gases generate plasma under the action of a microwave field, which modifies the surface and bulk phase of the desulfurized agent, making it more chemically active and easier to undergo chemical reactions; the role of oxygen is to regenerate the desulfurized agent.

[0025] Furthermore, the specific operation of the desulfurization reaction is as follows: the renewable iron oxide desulfurizing agent is placed in a fixed-bed reactor and reacted at a rate of 2000 h⁻¹. -1 Gas is introduced at air velocity and desulfurization reaction is carried out at 500℃.

[0026] The present invention discloses the following technical effects:

[0027] This invention uses silica nanofiber aerogel as a carrier to prepare an iron oxide / silica nanofiber aerogel composite desulfurizer through hydrothermal reaction of metal salt solution and oxidation treatment. It has the following advantages:

[0028] (1) The present invention uses nanofiber aerogel as a carrier. By utilizing the open pore structure, high flexibility and stable physical structure of nanofiber aerogel, it can not only provide support for the overall structure of the desulfurizer, but also promote the adsorption and reaction process of H2S and maintain the long-term cyclic use performance of the desulfurizer.

[0029] (2) The process steps of the present invention are simple, highly controllable, and easy to operate, which can meet the large market demand. The nanofiber aerogel has good support, high flexibility, high toughness and strength, high porosity and large specific surface area, and can realize multi-component composite and multi-level structure synergy.

[0030] (3) More importantly, this invention obtains desulfurization component iron oxide through hydrothermal reaction, and then utilizes the lattice diffusion of iron ions and the promoting effect of microwave radiation on the migration of metal ions during the low-temperature oxidation process to produce a significant Kirkendall effect, thereby causing iron oxide to generate a large number of lattice defects (metal ion defects and oxygen vacancies), and even transforming it into a hollow structure; during the regeneration process of the desulfurizer, by soaking in KF and K3P solutions, the fluorine and phosphorus elements are enhanced to combine with the metal, weakening the metal-sulfur chemical bond. At the same time, microwave radiation combined with hydrogen and argon gas is used to treat the surface defects of the adsorption saturated desulfurizer, generating a large number of sulfur vacancies (such as... Figure 1 (As shown). Based on this, the lattice defects and surface defects contained in the desulfurizer are beneficial to the adsorption and dissociation of oxygen during the oxidation regeneration process. They also help to weaken the chemical bonds between metal and sulfur, reduce the activation energy of bond breaking, and thus lower the regeneration reaction temperature. This reduces the diffusion resistance of oxygen and sulfur ions, allowing the desulfurizer to avoid the adverse effects of high-temperature sintering, maintain a high gas-solid reaction rate and mass transfer efficiency, and improve the recyclability of the desulfurizer. Tests show that the desulfurizer prepared by the method of this invention not only achieves a single-use active component utilization rate of over 99.9%, but also achieves a regeneration rate of 99% even when the regeneration reaction temperature is reduced to 420℃. After twenty sulfurization-regeneration cycles, it still maintains a 99.0% active component utilization rate. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 The sulfur vacancy concentrations before and after the desulfurizer in Example 1 was soaked in KF solution and K3P solution for 12 hours each, and then heat-treated with hydrogen and argon were compared. Detailed Implementation

[0033] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0034] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0035] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0036] Various modifications and variations can be made to the specific embodiments described in this specification without departing from the scope or spirit of the invention, as will be apparent to those skilled in the art. Other embodiments derived from this specification will also be apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0037] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.

[0038] The silica nanofiber aerogel carriers used in the following examples and comparative examples have a porosity of 99%, and the average diameter of the silica nanofibers is 500 nm. Silica nanofiber aerogel carriers are commercially available or can be prepared using conventional methods, such as airflow-assisted electrospinning, nanofiber remodeling, and freeze-drying to prepare silica nanofiber aerogels from SiO2. Specific preparation details are not limited, as long as the requirements for porosity and average nanofiber diameter are met. Specific preparation details do not affect the technical effectiveness of this solution.

[0039] The testing and calculation methods for sulfur capacity, active component utilization rate, and desulfurizer regeneration rate in the following examples and comparative examples are as follows:

[0040] The desulfurization performance of the samples was evaluated using breakthrough sulfur capacity as the indicator. The H2S concentration in the inlet gas was 1000 ppm. When the H2S concentration in the outlet gas reached 300 ppm, it was considered that the desulfurizing agent had broken through; the time taken for this to occur was considered the breakthrough time. Breakthrough sulfur capacity is converted into the mass (g) of elemental sulfur absorbed by 100g of desulfurizing agent from the start of the experiment until the breakthrough time. The detailed calculation method is as follows:

[0041]

[0042] Where: F is the flow rate of the simulated gas (mL / min), M s The molar mass of S is 32.06 g / mol, and the molar mass of V is V. m The molar volume of the gas at 25℃ and 101.325 kPa is 24.5 L / mol; C0 and C represent the inlet and outlet concentrations of H2S (ppm), respectively; M 脱硫剂 Corresponding to the mass (g) of the desulfurizing agent.

[0043] Utilization rate of active components = actual sulfur capacity / theoretical sulfur capacity × 100%.

[0044] Regeneration rate = (mass of desulfurizer lost during regeneration / mass of desulfurizer increased during desulfurization reaction) × 100%.

[0045] Example 1

[0046] (1) The preparation of renewable iron oxide desulfurizer is as follows:

[0047] 1) Preparation of desulfurizing agent precursor: 0.4g of silica nanofiber aerogel carrier was subjected to hydrothermal reaction in 100mL of 0.1mol / L hydrothermal reaction solution (ferric nitrate solution) at a temperature of 80℃ for 1h. During the hydrothermal reaction, the active component iron oxide was generated in the silica nanofiber aerogel carrier. After the hydrothermal reaction was completed, the desulfurizing agent precursor was obtained by drying.

[0048] 2) Preparation of desulfurizing agent: The desulfurizing agent precursor obtained in step 1) is oxidized under a microwave field of 1500W (a mixed gas with an oxygen concentration of 1 vol% is introduced, the equilibrium gas is nitrogen, and it is calcined at 200℃ for 1 h) to obtain a regenerable iron oxide desulfurizing agent (the Fe2O3 content in the desulfurizing agent is 50 wt%).

[0049] (2) Application of desulfurizing agent: The desulfurizing agent (0.1g) prepared in this embodiment was placed in a fixed-bed reactor and reacted at a space velocity of 2000 h⁻¹. -1 Texaco simulated coal gas is introduced and a desulfurization reaction is carried out at 500°C until absorption saturation.

[0050] After the desulfurization reaction was completed, the sulfur capacity of the desulfurizing agent was found to be 29.99%, and the utilization rate of the active component was 99.90%.

[0051] (3) Regeneration of desulfurizing agent: After the desulfurization reaction is completed, the desulfurizing agent saturated with H2S is soaked in 1 mmol / L KF solution and K3P solution for 12 h each. After drying, it is subjected to heat treatment under a microwave field of 1000 W by sequentially introducing a mixed gas with a hydrogen concentration of 2 vol% (2 vol% hydrogen + 98 vol% nitrogen), argon, and a mixed gas with an oxygen concentration of 1 vol% (1 vol% oxygen + 99 vol% nitrogen). The heat treatment temperature for hydrogen is 500℃ and the heat treatment time is 30 min; the heat treatment temperature for argon is 500℃ and the heat treatment time is 30 min; the heat treatment temperature for oxygen is 420℃ and the heat treatment time is 2 h. The space velocity is 2000 h⁻¹. -1 The desulfurizing agent is then fully regenerated. This regenerated agent is then used in the desulfurization reaction of Texaco simulated coal gas under the same conditions. After the desulfurization reaction is complete, regeneration is performed again under the same conditions.

[0052] After twenty cycles of sulfidation / regeneration, the desulfurizer showed a regeneration rate of 99.0%, a sulfur capacity of 29.69%, and an active component utilization rate of 99.0%.

[0053] Figure 1 In this embodiment, the sulfur vacancy concentrations of the desulfurizing agent after absorption saturation were compared before and after soaking in KF solution and K3P solution for 12 hours each, followed by heat treatment with hydrogen and argon gas. The sample before modification represents the desulfurization reaction to absorption saturation, while the sample after modification represents the desulfurizing agent after absorption saturation, having been soaked in KF solution and K3P solution for 12 hours each, followed by heat treatment with hydrogen and argon gas. Figure 1 It can be seen that the concentration of sulfur vacancies in the sample increases after soaking in KF solution and K3P solution and heat treatment with hydrogen and argon.

[0054] Example 2

[0055] (1) The preparation of renewable iron oxide desulfurizer is as follows:

[0056] 1) Preparation of desulfurizing agent precursor: 0.4g of silica nanofiber aerogel carrier was subjected to hydrothermal reaction in 100mL of 0.2mol / L hydrothermal reaction solution (ferric nitrate solution) at a temperature of 90℃ for 1h. During the hydrothermal reaction, the active component iron oxide was generated in the silica nanofiber aerogel carrier. After the hydrothermal reaction was completed, the desulfurizing agent precursor was obtained by drying.

[0057] 2) Preparation of desulfurizing agent: The desulfurizing agent precursor obtained in step 1) is oxidized under a microwave field of 1500W (a mixed gas with an oxygen concentration of 2 vol% is introduced, the equilibrium gas is nitrogen, and it is calcined at 250℃ for 1 h) to obtain a renewable iron oxide desulfurizing agent (the Fe2O3 content in the desulfurizing agent is 61 wt%).

[0058] (2) Application of desulfurizing agent: The desulfurizing agent (0.1g) prepared in this embodiment was placed in a fixed-bed reactor and reacted at a space velocity of 2000 h⁻¹. -1 Texaco simulated coal gas is introduced and a desulfurization reaction is carried out at 500°C until absorption saturation.

[0059] After the desulfurization reaction was completed, the sulfur capacity of the desulfurizing agent was found to be 36.51%, and the utilization rate of the active component was 99.98%.

[0060] (3) Regeneration of desulfurizing agent: After the desulfurization reaction is completed, the desulfurizing agent saturated with H2S is soaked in 2 mmol / L KF solution and K3P solution for 12 h each. After drying, it is subjected to heat treatment under a microwave field of 1000 W by sequentially introducing a mixed gas with a hydrogen concentration of 4 vol% (4 vol% hydrogen + 96 vol% nitrogen), argon, and a mixed gas with an oxygen concentration of 2 vol% (2 vol% oxygen + 98 vol% nitrogen). The heat treatment temperature for hydrogen is 500℃ and the heat treatment time is 30 min; the heat treatment temperature for argon is 500℃ and the heat treatment time is 30 min; the heat treatment temperature for oxygen is 420℃ and the heat treatment time is 2 h. The space velocity is 2000 h⁻¹. -1 The desulfurizing agent is then fully regenerated. This regenerated agent is then used in the desulfurization reaction of Texaco simulated coal gas under the same conditions. After the desulfurization reaction is complete, regeneration is performed again under the same conditions.

[0061] After twenty cycles of sulfidation / regeneration, the desulfurizer showed a regeneration rate of 96%, a sulfur capacity of 36.42%, and an active component utilization rate of 99.89%.

[0062] Example 3

[0063] (1) The preparation of renewable iron oxide desulfurizer is as follows:

[0064] 1) Preparation of desulfurizing agent precursor: 0.4g of silica nanofiber aerogel carrier was subjected to hydrothermal reaction in 100mL of 0.3mol / L hydrothermal reaction solution (ferric nitrate solution) at 100℃ for 1h. During the hydrothermal reaction, the active component iron oxide was generated in the silica nanofiber aerogel carrier. After the hydrothermal reaction was completed, the desulfurizing agent precursor was obtained by drying.

[0065] 2) Preparation of desulfurizing agent: The desulfurizing agent precursor obtained in step 1) is oxidized under a microwave field of 1500W (a mixed gas with an oxygen concentration of 3 vol% is introduced, the equilibrium gas is nitrogen, and it is calcined at 300℃ for 1 h) to obtain a renewable iron oxide desulfurizing agent (the Fe2O3 content in the desulfurizing agent is 72 wt%).

[0066] (2) Application of desulfurizing agent: The desulfurizing agent (0.1g) prepared in this embodiment was placed in a fixed-bed reactor and reacted at a space velocity of 2000 h⁻¹. -1 Texaco simulated coal gas is introduced, and a desulfurization reaction is carried out at 500°C.

[0067] After the desulfurization reaction was completed, the sulfur capacity of the desulfurizing agent was found to be 43.19%, and the utilization rate of the active component was 99.99%.

[0068] (3) Regeneration of desulfurizing agent: After the desulfurization reaction is completed, the desulfurizing agent saturated with H2S is soaked in 3 mmol / L KF solution and K3P solution for 12 h each. After drying, it is subjected to heat treatment under a microwave field by sequentially introducing a mixed gas with a hydrogen concentration of 6 vol% (6 vol% hydrogen + 94 vol% nitrogen), argon, and a mixed gas with an oxygen concentration of 3 vol% (3 vol% oxygen + 97 vol% nitrogen). The heat treatment temperature for hydrogen is 500℃ and the heat treatment time is 30 min; the heat treatment temperature for argon is 500℃ and the heat treatment time is 30 min; the heat treatment temperature for oxygen is 420℃ and the heat treatment time is 2 h; the space velocity is 2000 h⁻¹. -1 The desulfurizing agent is then fully regenerated. This regenerated agent is then used in the desulfurization reaction of Texaco simulated coal gas under the same conditions. After the desulfurization reaction is complete, regeneration is performed again under the same conditions.

[0069] After twenty cycles of sulfidation / regeneration, the desulfurizer showed a regeneration rate of 97%, a sulfur capacity of 43.00%, and an active component utilization rate of 99.97%.

[0070] Example 4

[0071] (1) The preparation of renewable iron oxide desulfurizer is as follows:

[0072] 1) Preparation of desulfurizing agent precursor: 0.4g of silica nanofiber aerogel carrier was subjected to hydrothermal reaction in 100mL of 0.4mol / L hydrothermal reaction solution at 110℃ for 1h. During the hydrothermal reaction, the active component iron oxide was generated in the silica nanofiber aerogel carrier. After the hydrothermal reaction was completed, the desulfurizing agent precursor was obtained by drying.

[0073] 2) Preparation of desulfurizing agent: The desulfurizing agent precursor obtained in step 1) is subjected to secondary oxidation treatment under a microwave field of 1500W (a mixed gas with an oxygen concentration of 4 vol% is introduced, the equilibrium gas is nitrogen, and the mixture is calcined at 350℃ for 1 h) to obtain a renewable iron oxide desulfurizing agent (the Fe2O3 content in the desulfurizing agent is 81 wt%).

[0074] (2) Application of desulfurizing agent: The desulfurizing agent (0.1g) prepared in this embodiment was placed in a fixed-bed reactor and reacted at a space velocity of 2000 h⁻¹. -1 Texaco simulated coal gas is introduced and a desulfurization reaction is carried out at 500°C until absorption saturation.

[0075] After the desulfurization reaction was completed, the sulfur capacity of the desulfurizing agent was found to be 47.13%, and the utilization rate of the active component was 96.99%.

[0076] (3) Regeneration of desulfurizing agent: After the desulfurization reaction is completed, the desulfurizing agent saturated with H2S is soaked in 4 mmol / L KF solution and K3P solution for 12 h each. After drying, it is subjected to heat treatment under a microwave field of 1000 W by sequentially introducing a mixed gas with a hydrogen concentration of 8 vol% (8 vol% hydrogen + 92 vol% nitrogen), argon, and a mixed gas with an oxygen concentration of 4 vol% (4 vol% oxygen + 96 vol% nitrogen). The heat treatment temperature for hydrogen is 500℃ and the heat treatment time is 30 min; the heat treatment temperature for argon is 500℃ and the heat treatment time is 30 min; the heat treatment temperature for oxygen is 420℃ and the heat treatment time is 2 h; the space velocity is 2000 h⁻¹. -1 The desulfurizing agent is then fully regenerated. This regenerated agent is then used in the desulfurization reaction of Texaco simulated coal gas under the same conditions. After the desulfurization reaction is complete, regeneration is performed again under the same conditions.

[0077] After twenty cycles of sulfidation / regeneration, the desulfurizer showed a regeneration rate of 88%, a sulfur capacity of 45.52%, and an active component utilization rate of 93.71%.

[0078] Comparative Example 1

[0079] Commercially available iron oxide was used as the active component, and desulfurizing agent was prepared by mechanically mixing iron oxide and silica nanofiber aerogel at a certain mass ratio (50:50).

[0080] The specific operation of mechanical mixing is as follows: Fe2O3 is dispersed in water to prepare a Fe2O3 dispersion with a concentration of 0.1 mol / L, silica nanofiber aerogel is added, and after mechanical stirring for 3 hours, the silica nanofiber aerogel is taken out and dried to obtain a desulfurizing agent (the Fe2O3 content in the desulfurizing agent is 50 wt%).

[0081] Under the same desulfurization reaction experimental conditions as in Example 1, the initial sulfur capacity of the mechanically mixed iron oxide / silica nanofiber aerogel desulfurizer prepared in this comparative example was tested to be 10.1%, and the utilization rate of the active component was 33%.

[0082] After desulfurization, regeneration was carried out under the same conditions as in Example 1. After twenty sulfidation / regeneration cycles, the regeneration rate of the mechanically mixed Fe2O3 / silica nanofiber aerogel desulfurizer was 59%, the sulfur capacity decreased to 6.0%, and the utilization rate of the active component was 19.9%.

[0083] Comparative Example 2

[0084] Same as Example 1, except that the use of microwave field is omitted in step 2) of the preparation of renewable iron oxide desulfurizer, and oxidation treatment is carried out under non-microwave conditions.

[0085] Under the same desulfurization reaction experimental conditions as in Example 1, the initial sulfur capacity of the desulfurizing agent prepared in this comparative example was tested to be 18.8%, and the utilization rate of the active component was 62.9%.

[0086] After desulfurization, regeneration was carried out under the same conditions as in Example 1. After twenty sulfidation / regeneration cycles, the regeneration rate of the desulfurizing agent was 80.2%, the sulfur capacity decreased to 15.1%, and the utilization rate of the active component was 50.5%.

[0087] Comparative Example 3

[0088] The preparation steps of the regenerable iron oxide desulfurizer are the same as in Example 1, the desulfurization reaction conditions are the same as in Example 1, but the regeneration steps of the desulfurizer are different from those in Example 1.

[0089] The regeneration steps in this comparative example are as follows: After the desulfurization reaction is completed, the desulfurizing agent saturated with H2S is sequentially heat-treated under a microwave field by introducing a mixed gas with a hydrogen concentration of 2 vol% (2 vol% hydrogen + 98 vol% nitrogen), argon, and a mixed gas with an oxygen concentration of 1 vol% (1 vol% oxygen + 99 vol% nitrogen). The heat treatment temperature for hydrogen is 500℃ and the heat treatment time is 30 min; the heat treatment temperature for argon is 500℃ and the heat treatment time is 30 min; the heat treatment temperature for oxygen is 420℃ and the heat treatment time is 2 h; the space velocity is 2000 h⁻¹. -1 This process yields fully regenerated desulfurizer. The regenerated desulfurizer is then used in the desulfurization reaction of Texaco simulated coal gas, under the same conditions as above (space velocity 2000 h⁻¹). -1 (Temperature 500℃). After the desulfurization reaction is completed, regeneration is carried out again under the same regeneration conditions.

[0090] After twenty cycles of sulfidation / regeneration, the desulfurizer's regeneration rate was 62.9%, its sulfur capacity was 17.9%, and its active component utilization rate was 59.7%.

[0091] Comparative Example 4

[0092] The preparation steps of the regenerable iron oxide desulfurizer are the same as in Example 1, the desulfurization reaction conditions are the same as in Example 1, but the regeneration steps of the desulfurizer are different from those in Example 1.

[0093] The regeneration steps in this comparative example are as follows: After the desulfurization reaction is completed, the desulfurizing agent saturated with H2S is soaked in a 1 mmol / L KF solution for 12 h. After drying, it is subjected to heat treatment under a microwave field by sequentially introducing a mixed gas with a hydrogen concentration of 2 vol% (2 vol% hydrogen + 98 vol% nitrogen), argon, and a mixed gas with an oxygen concentration of 1 vol% (1 vol% oxygen + 99 vol% nitrogen). The heat treatment temperature for argon is 500℃ and the heat treatment time is 30 min; the heat treatment temperature for oxygen is 420℃ and the heat treatment time is 2 h; the space velocity is 2000 h⁻¹ for all cases. -1 This process yields fully regenerated desulfurizer. The regenerated desulfurizer is then used in the desulfurization reaction of Texaco simulated coal gas, under the same conditions as above (space velocity 2000 h⁻¹). -1 (Temperature 500℃). After the desulfurization reaction is completed, regeneration is carried out again under the same regeneration conditions.

[0094] After twenty cycles of sulfidation / regeneration, the desulfurizer showed a regeneration rate of 70.2%, a sulfur capacity of 20.4%, and an active component utilization rate of 65.3%.

[0095] Comparative Example 5

[0096] The preparation steps of the regenerable iron oxide desulfurizer are the same as in Example 1, the desulfurization reaction conditions are the same as in Example 1, but the regeneration steps of the desulfurizer are different from those in Example 1.

[0097] The regeneration steps in this comparative example are as follows: After the desulfurization reaction is completed, the desulfurizing agent saturated with H2S is sequentially immersed in 1 mmol / L KF solution and K3P solution for 12 h each. After drying, it is subjected to heat treatment under a microwave field by sequentially introducing a mixed gas (1 vol% oxygen + 99 vol% nitrogen) with argon and oxygen concentrations (the heat treatment temperature for argon is 500℃ and the heat treatment time is 30 min; the heat treatment temperature for oxygen is 420℃ and the heat treatment time is 2 h; the space velocity is 2000 h⁻¹ for both cases). -1 This process yields fully regenerated desulfurizer. The regenerated desulfurizer is then used in the desulfurization reaction of Texaco simulated coal gas, under the same conditions as above (space velocity 2000 h⁻¹).-1 (Temperature 500℃). After the desulfurization reaction is completed, regeneration is carried out again under the same regeneration conditions.

[0098] After twenty cycles of sulfidation / regeneration, the desulfurizer showed a regeneration rate of 73.3%, a sulfur capacity of 22.1%, and an active component utilization rate of 73.0%.

[0099] Comparative Example 6

[0100] The preparation steps of the regenerable iron oxide desulfurizer are the same as in Example 1, the desulfurization reaction conditions are the same as in Example 1, but the regeneration steps of the desulfurizer are different from those in Example 1.

[0101] The regeneration steps in this comparative example are as follows: After the desulfurization reaction is completed, the desulfurizing agent saturated with H2S is sequentially immersed in 1 mmol / L KF solution and K3P solution for 12 h each. After drying, it is sequentially heat-treated with hydrogen, argon, and oxygen (gas concentration and heat treatment conditions are the same as in Example 1, without microwave intervention) to obtain a fully regenerated desulfurizing agent. The regenerated desulfurizing agent is then used in the desulfurization reaction of Texaco simulated coal gas under the same desulfurization reaction conditions (space velocity 2000 h⁻¹). -1 (Temperature 500℃). After the desulfurization reaction is completed, regeneration is carried out again under the same regeneration conditions.

[0102] After twenty cycles of sulfidation / regeneration, the desulfurizer showed a regeneration rate of 82.1%, a sulfur capacity of 27.0%, and an active component utilization rate of 89.9%.

[0103] Comparative Example 7

[0104] The preparation steps of the regenerable iron oxide desulfurizer are the same as in Example 1, the desulfurization reaction conditions are the same as in Example 1, but the regeneration steps of the desulfurizer are different from those in Example 1.

[0105] The regeneration steps in this comparative example are as follows: using a mixed gas with an oxygen volume concentration of 2 vol% (2 vol% oxygen + 98 vol% nitrogen), at a temperature of 420°C and a space velocity of 2000 h⁻¹. -1 The desulfurizing agent, after being saturated with H2S, is regenerated to obtain regenerated desulfurizing agent. This regenerated desulfurizing agent is then used in the desulfurization reaction of Texaco simulated coal gas, under the same conditions as above (space velocity 2000 h⁻¹). -1 (Temperature 500℃). After the desulfurization reaction is completed, regeneration is carried out again under the same regeneration conditions.

[0106] After twenty cycles of sulfidation / regeneration, the desulfurizer showed a regeneration rate of 73.3%, a sulfur capacity of 26.2%, and an active component utilization rate of 87.3%.

[0107] Comparative Example 8

[0108] Similar to Comparative Example 7, the only difference is that the regeneration temperature is 850℃. After twenty cycles of sulfidation / regeneration, the regeneration rate of the desulfurizer is 95.1%, the sulfur capacity is 27.6%, and the utilization rate of the active component is 92.0%.

[0109] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A method for regenerating a regenerable iron oxide desulfurizer, characterized in that, Includes the following steps: The regenerated iron oxide desulfurizer after desulfurization reaction was soaked in KF solution and K3P solution for 12 hours each, dried, and then placed under a microwave field. Hydrogen, argon and oxygen were introduced sequentially for heat treatment to obtain the regenerated desulfurizer. The preparation steps of the renewable iron oxide desulfurizer include: carrying out a hydrothermal reaction of a silica nanofiber aerogel carrier in an iron nitrate solution to obtain a desulfurizer precursor; and subjecting the desulfurizer precursor to oxidation treatment under a microwave field to obtain the renewable iron oxide desulfurizer. The specific parameters of the oxidation treatment include: oxygen concentration of 1-4 vol%, calcination temperature of 200-350℃, and calcination time of 1 h.

2. The regeneration method as described in claim 1, characterized in that, The concentration of the ferric nitrate solution is 0.1-0.4 mol / L.

3. The regeneration method as described in claim 1, characterized in that, The hydrothermal reaction is carried out at a temperature of 80-110℃ for 1-4 hours.

4. The regeneration method as described in claim 1, characterized in that, The microwave field has a microwave condition of 1500W.

5. The regeneration method as described in claim 1, characterized in that, The concentration of the KF solution is 1-4 mmol / L, and the concentration of the K3P solution is 1-4 mmol / L.

6. The regeneration method as described in claim 1, characterized in that, The concentration of hydrogen is 2-8 vol%, and the concentration of oxygen is 1-4 vol%.

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