Preparation method of coal gas desulfurization agent capable of being efficiently regenerated

Abstract

The application discloses a preparation method of a coal gas desulfurizer capable of being efficiently regenerated, and belongs to the technical field of coal chemical desulfurizer preparation. The preparation method comprises the following steps: sequentially immersing a silica nanofiber aerogel carrier in a mixed solution of zinc nitrate and iron nitrate, a KNO3 solution, a NaF solution and a NaCl solution for treatment to obtain a desulfurizer precursor; and performing microwave low-temperature calcination on the desulfurizer precursor to generate active component ZnFe2O4 in the silica nanofiber aerogel carrier, so as to obtain the coal gas desulfurizer capable of being efficiently regenerated. The preparation process route of the desulfurizer is simple and easy to implement, the prepared desulfurizer has excellent regeneration performance, the regeneration temperature is low, and the performance requirements of desulfurizer industrialization can be met. On the other hand, the fiber material with high flexibility and rich porosity 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] The present application relates to the technical field of coal chemical desulfurizer preparation, and particularly relates to a preparation method of a coal gas desulfurizer capable of being efficiently regenerated. BACKGROUND

[0002] As one of the three fossil energies, coal has an important position as a basic energy in economic development, but various environmental problems caused by direct combustion of coal have to be paid attention to. The integrated gasification combined cycle (IGCC) technology is based on clean and efficient utilization of coal, and has been widely applied in many countries and regions. Coal gas, as a power source and raw material in the IGCC technology, contains a large amount of sulfides, more than 90% of which are hydrogen sulfide (H2S) gas. Hydrogen sulfide not only causes corrosion of industrial equipment and poisoning of catalysts, but also causes threats to ecological environment and human health after being discharged into the atmosphere. Therefore, hydrogen sulfide in the coal gas must be completely removed before the coal gas is used.

[0003] The dry desulfurization utilizes metal oxides in the solid desulfurizer to convert and remove H2S by chemical reaction, and has the advantages of simple process flow, no waste water and waste acid treatment problem, low energy consumption, small corrosion to equipment, low cost and the like. Studies have shown that the desulfurizer with zinc oxide as an active component has higher desulfurization accuracy and desulfurization efficiency than other oxide desulfurizers, but zinc oxide is easy to volatilize in the high-temperature regeneration process, resulting in loss of active components and serious performance decline. Copper oxide has strong affinity and adsorption capacity with hydrogen sulfide. Some scholars have found that the copper oxide desulfurizer has higher desulfurization accuracy, is less affected by temperature and has good regeneration performance.

[0004] Then, the existing dry desulfurization technology has the disadvantages of large amount of desulfurizer loading, frequent replacement of desulfurizer, difficult regeneration of waste desulfurizer and difficult solid waste treatment. Although the preparation method and regeneration process of the existing desulfurizer are relatively mature, there are still the disadvantages of high regeneration temperature, short service life and high operation cost caused by difficult regeneration. Therefore, the existing desulfurizer cannot meet the requirements of actual industrial application, and development of a new type of solid desulfurizer capable of being efficiently regenerated, which has high desulfurization efficiency, speed and selectivity, is still one of the goals of gas desulfurization technology. SUMMARY

[0005] The present application relates to the technical field of coal chemical desulfurizer preparation, and particularly relates to a preparation method of a coal gas desulfurizer capable of being efficiently regenerated.

[0006] To achieve the above object, the present application provides the following solutions.

[0007] One of the technical solutions of the present application: a preparation method of a coal gas desulfurizer capable of efficient regeneration, comprising the following steps: sequentially immersing a silica nanofiber aerogel carrier in a mixed solution of zinc nitrate and iron nitrate, a KNO3 solution, a NaF solution, and a NaCl solution to obtain a desulfurizer precursor; and performing microwave low-temperature calcination on the desulfurizer precursor to generate active component ZnFe2O4 in the silica nanofiber aerogel carrier, thereby obtaining the coal gas desulfurizer capable of efficient regeneration.

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

[0009] Further, the molar ratio of zinc nitrate to iron nitrate in the mixed solution of zinc nitrate and iron nitrate is 1:2, and the concentration of zinc nitrate is 0.1 mol / L.

[0010] Further, the concentration of each of the KNO3 solution, the NaF solution, and the NaCl solution is 1-4 mmol / L.

[0011] Further, the volume ratio of the silica nanofiber aerogel carrier to the mixed solution of zinc nitrate and iron nitrate, the KNO3 solution, the NaF solution, and the NaCl solution in the immersion process is 1:1, and the immersion time is 24 h.

[0012] The immersion of the silica nanofiber aerogel carrier in the mixed solution of zinc nitrate and iron nitrate, the KNO3 solution, the NaF solution, and the NaCl solution is an equal-volume impregnation process between the aerogel solid and the liquid, and the carrier can absorb all the impregnation liquid in the equal-volume impregnation process. The immersion of the silica nanofiber aerogel carrier in the KNO3 solution, the NaF solution, and the NaCl solution, instead of in a mixed solution of KNO3, NaF, and NaCl, is to avoid competition between different ions and improve the impregnation loading effect, so that all ions can be loaded on the carrier.

[0013] Further, the specific parameters of the microwave low-temperature calcination include: an oxygen concentration of 5-20 vol%, a microwave power of 1500-3000 W, a calcination temperature of 240°C, and a calcination time of 2 h.

[0014] The second technical solution of the present application: a coal gas desulfurizer capable of efficient regeneration prepared by the above preparation method.

[0015] Further, the coal gas desulfurizer capable of efficient regeneration takes the silica nanofiber aerogel as a carrier, and the carrier is loaded with active component ZnFe2O4, which can be referred to as a ZnFe2O4 / silica nanofiber aerogel composite desulfurizer.

[0016] Furthermore, the ZnFe2O4 content in the highly efficient regenerable coal gas desulfurizer is 62.0 wt%.

[0017] The third technical solution of the present invention: a regeneration method for the above-mentioned highly efficient regenerable coal gas desulfurizer, comprising the following steps: using a mixed gas with an oxygen concentration of 2 vol%, at a temperature of 450°C for 2000 h. -1 The desulfurizing agent for coal gas that has undergone desulfurization reaction is regenerated at a space velocity of 0.5 to obtain the regenerated coal gas desulfurizing agent.

[0018] Furthermore, the mixed gas is a mixture of oxygen and nitrogen (i.e., nitrogen is used as the balance gas), which can be expressed as 2 vol% oxygen + 98 vol% nitrogen.

[0019] Furthermore, the specific operation of the desulfurization reaction is as follows: A highly efficient regenerable coal gas 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℃.

[0020] The present invention discloses the following technical effects:

[0021] This invention utilizes silica nanofiber aerogel as a carrier to prepare a ZnFe2O4 / silica nanofiber aerogel composite desulfurizer through methods such as metal salt solution impregnation and microwave low-temperature calcination. It possesses the following advantages:

[0022] (1) This invention uses silica nanofiber aerogel as a carrier to prepare desulfurizer. It utilizes the open pore structure, high flexibility and stable physical structure of nanofiber aerogel, and combines the excellent wear resistance and heat resistance of silica nanofiber. While providing support for the overall structure of the desulfurizer, the stable physical structure and rich pore structure of nanofiber aerogel can promote the adsorption and reaction process of desulfurizer and maintain the long-term cyclic use performance of desulfurizer.

[0023] (2) The process steps of the present invention are simple, highly controllable, and easy to operate, which can meet the large market demand. The silica 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.

[0024] (3) More importantly, the present application combines zinc with iron, in addition to being able to form a composite oxide, improve the stability of zinc, the regeneration performance of the desulfurizer, also can be based on the difference in size of zinc, iron ions, the lattice structure stability of the composite oxide is reduced; on this basis, by using the lattice diffusion of iron ions in the low temperature calcination process, the migration of alkali metal potassium, sodium, the promotion effect of non-metallic fluorine, chlorine on oxygen vacancy and microwave radiation on metal ion migration, produce significant cohen-tal effect, and then make zinc iron composite oxide produce a large number of lattice defects (metal ion defects and oxygen vacancies), even change to hollow structure (such as Figure 1 and Figure 2 shown); on this basis, after the desulfurizer is subjected to desulfurization reaction, due to the replacement process of sulfur ions and oxygen ions, but the diffusion rates of the two ions are different, therefore, the cohen-tal effect of metal ions still exists, and a large number of lattice defects (metal ion defects and sulfur vacancies, such as Figure 3 shown) are still produced. Taking the oxygen regeneration process of the desulfurizer as an example, the existence of the lattice defects of the sulfidation product is not only beneficial to the adsorption and dissociation of oxygen, but also beneficial to weakening the chemical bond between metal and sulfur and reducing the bond activation energy, thereby reducing the regeneration reaction temperature, avoiding the adverse effects of high temperature sintering on the desulfurizer, maintaining the efficient gas-solid reaction rate and mass transfer efficiency, and improving the cyclic use performance of the desulfurizer. Through testing, the desulfurizer prepared by the method of the present application not only has a single-time active component utilization rate of more than 99.9%, but also has a regeneration reaction temperature reduced to 450 DEG C, a desulfurizer regeneration rate of 97%, and an active component utilization rate of 99.9% after ten cycles of sulfidation-regeneration. BRIEF DESCRIPTION OF DRAWINGS

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments. Obviously, the drawings described below only show some embodiments of the present application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0026] Figure 1 TEM characterization diagram of the desulfurizer prepared for example 1, wherein a, b and c respectively represent diagrams of different magnifications;

[0027] Figure 2 EPR characterization diagram of the desulfurizer prepared for example 1 and comparative example 1;

[0028] Figure 3 TEM characterization diagram of the desulfurizer prepared for example 1 after desulfurization reaction, wherein a, b and c respectively represent diagrams of different magnifications. DETAILED DESCRIPTION

[0029] Various exemplary embodiments of the present application will now be described in detail, which should be considered to be merely illustrative of certain aspects, features and embodiments of the present application, not a limitation thereof.

[0030] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the present application. Additionally, the use of the term "about" in relation to a value or range of values is intended to include each and every value falling within the range and each and every value falling within the range, unless otherwise clear from the context. The upper and lower limits of these smaller ranges can independently be included or excluded in the stated ranges.

[0031] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. Although preferred methods and materials are described, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present application. All documents mentioned herein are incorporated by reference to disclose and describe in full the methods and / or materials which are described therein. In the case of conflict between the present specification and any document incorporated herein by reference, the present specification will control.

[0032] Various modifications and changes can be made to the specific embodiments of the present application described herein without departing from the scope or spirit of the application. Other embodiments of the application will be apparent to those of ordinary skill in the art from the description and examples herein. The description and examples are illustrative of the application and are not intended to limit the scope of the application.

[0033] As used herein, the terms "comprises", "comprising", "includes", "including", "has", "having", "contains", "containing", and the like are open-ended terms that are intended to denote the inclusion of elements or steps, but not to exclude any other elements or steps.

[0034] Normal temperature or room temperature as referred to in the following examples and comparative examples specifically means 20-25°C.

[0035] The silica nanofiber aerogel support used in the following examples and comparative examples has a porosity of 99%, and the average diameter of the silica nanofiber therein is 500 nm. The silica nanofiber aerogel support can be commercially available or can be prepared by conventional methods, such as preparing SiO2 into silica nanofiber aerogel by using airflow-assisted-electrospinning, nanofiber bulk reconstruction, and freeze-drying technology, and the specific preparation details are not limited as long as the requirements for porosity and average diameter of nanofiber are met, and the specific preparation details do not affect the presentation of the technical effects of the present solution.

[0036] The testing and calculation methods of sulfur capacity, active component utilization rate and desulfurizer regeneration rate in the following examples and comparative examples are as follows:

[0037] The desulfurization performance of the sample is evaluated by breakthrough sulfur capacity. The H2S concentration in the inlet gas is 1000 ppm, and when the H2S concentration in the outlet gas reaches 300 ppm, it is considered that the desulfurizer has broken through, and the time at this point is considered as the breakthrough time. The breakthrough sulfur capacity is converted into the mass of elemental sulfur (g) absorbed by 100 g of the desulfurizer from the start of the experiment to the breakthrough time. The detailed calculation method is as follows:

[0038]

[0039] In the formula, F is the flow rate of the simulated coal gas (mL / min), M s is the molar mass of S (32.06 g / mol), V m is the molar volume of the gas at 25°C and 101.325 kPa (24.5 L / mol); C0 and C represent the inlet and outlet concentrations of H2S (ppm), respectively; M 脱硫剂 corresponds to the mass of the desulfurizer (g).

[0040] Active component utilization rate = actual sulfur capacity / theoretical sulfur capacity x 100%.

[0041] Regeneration rate = (mass lost by the desulfurizer during regeneration / mass increased by the desulfurizer during desulfurization) x 100%.

[0042] Example 1

[0043] A method for preparing a coal gas desulfurizer that can be efficiently regenerated, comprising the following steps:

[0044] (1) Metal ion impregnation: Dissolve 2.97 g of zinc nitrate (specifically Zn(NO3)2·6H2O, 0.01 mol) and 8.08 g of iron nitrate (specifically Fe(NO3)3·9H2O, 0.02 mol) as precursors of the active component ZnFe2O4 in 100 mL of water to obtain a mixed solution of zinc nitrate and iron nitrate as an impregnation solution; immerse the silica nanofiber aerogel carrier in the impregnation solution at room temperature for 24 h (by volume ratio, silica nanofiber aerogel: impregnation solution = 1:1), and dry the water after the immersion treatment;

[0045] (2) Preparation of desulfurizer precursor: immerse the silica nanofiber aerogel carrier after step (1) in 1 mmol / L KNO3 solution, NaF solution, and NaCl solution at room temperature for 24 h each time, and dry the water after each immersion treatment to obtain the desulfurizer precursor;

[0046] (3) Preparation of the coal gas desulfurizer with high regeneration efficiency: the desulfurizer precursor obtained in step (2) was subjected to microwave low-temperature calcination in a mixed gas with an oxygen concentration of 5 vol% (5 vol% oxygen + 95 vol% nitrogen) at a microwave power of 1500 W, the temperature of the low-temperature calcination was 240°C, and the calcination time was 2 h, to generate the active component ZnFe2O4 in the silica nanofiber aerogel carrier, thereby obtaining the coal gas desulfurizer with high regeneration efficiency (the content of ZnFe2O4 in the desulfurizer was 62.0 wt%).

[0047] The desulfurizer prepared in this example (0.1 g) was placed in a fixed bed reaction device, and the desulfurization reaction was carried out at a space velocity of 2000 h-1 and a temperature of 500°C. -1 The desulfurization reaction was carried out at a space velocity of 2000 h-1 and a temperature of 500°C.

[0048] After the desulfurization reaction was completed, the sulfur capacity of the desulfurizer reached 30.99%, and the utilization rate of the active component was 99.91%.

[0049] Then, the desulfurizer was regenerated for 3 h at a temperature of 450°C and a space velocity of 2000 h-1 using a mixed gas with an oxygen concentration of 2 vol% (2 vol% oxygen + 98 vol% nitrogen), and the regenerated desulfurizer was obtained. -1 The desulfurization reaction was carried out at a space velocity of 2000 h-1 and a temperature of 500°C.

[0050] After ten cycles of sulfurization / regeneration, the regeneration rate of the desulfurizer was 91%, the sulfur capacity was 29.93%, and the utilization rate of the active component was 96.49%.

[0051] Example 2

[0052] A method for preparing a coal gas desulfurizer with high regeneration efficiency, the steps of which are as follows:

[0053] (1) Metal ion impregnation: 2.97 g of the precursor of the active component ZnFe2O4 (specifically, Zn(NO3)2·6H2O, 0.01 mol) and 8.08 g of iron nitrate (specifically, Fe(NO3)3·9H2O, 0.02 mol) were dissolved in 100 mL of water to obtain a mixed solution of zinc nitrate and iron nitrate as an impregnation solution; the silica nanofiber aerogel carrier was soaked in the impregnation solution at room temperature for 24 h (the volume ratio of the silica nanofiber aerogel to the impregnation solution was 1:1), and the water was dried after the soaking treatment;

[0054] (2) Desulfurizer precursor preparation: the silica nanofiber aerogel carrier after the soaking treatment in step (1) is sequentially soaked in 2 mmol / L KNO3 solution, NaF solution, and NaCl solution with equal volume at room temperature for 24 h, and is air-dried after each soaking treatment to obtain a desulfurizer precursor;

[0055] (3) Preparation of the high-efficiency regenerable coal gas desulfurizer: the desulfurizer precursor obtained in step (2) is subjected to microwave low-temperature calcination in a mixed gas with an oxygen concentration of 10 vol% (10 vol% oxygen + 90 vol% nitrogen) at a microwave power of 2000 W, the low-temperature calcination temperature is 240℃, and the calcination time is 2 h, to generate the active component ZnFe2O4 in the silica nanofiber aerogel carrier, thereby obtaining the high-efficiency regenerable coal gas desulfurizer (the content of ZnFe2O4 in the desulfurizer is 62.0 wt%).

[0056] The desulfurizer (0.1 g) prepared in this example is placed in a fixed bed reaction device, and the desulfurization reaction is carried out at 500℃ under a space velocity of 2000 h -1 The Texaco simulated coal gas is introduced, and the desulfurization reaction is carried out at 500℃ until saturation absorption is achieved.

[0057] After the desulfurization reaction is completed, the sulfur capacity of the desulfurizer reaches 31.01%, and the active component utilization rate is 99.99%.

[0058] Then, the mixed gas with an oxygen volume concentration of 2 vol% (2 vol% oxygen + 98 vol% nitrogen) is used at a temperature of 450℃ and a space velocity of 2000 h -1 The desulfurizer is regenerated for 3 h, and the regenerated desulfurizer is obtained, which is continuously used for the desulfurization reaction of the Texaco simulated coal gas under the same conditions as above. After the desulfurization reaction is completed, the regeneration is again carried out under the same regeneration conditions.

[0059] After ten sulfurization / regeneration cycles, the regeneration rate of the desulfurizer is 94%, the sulfur capacity is 30.13%, and the active component utilization rate is 97.13%.

[0060] Example 3

[0061] A preparation method of a high-efficiency regenerable coal gas desulfurizer, the steps are as follows:

[0062] (1) Metal ion impregnation: 2.97 g of a precursor of the active component ZnFe2O4, specifically Zn(NO3)2·6H2O, 0.01 mol, and 8.08 g of Fe(NO3)3·9H2O, 0.02 mol, were dissolved in 100 mL of water to obtain a mixed solution of zinc nitrate and iron nitrate as an impregnation solution; the silica nanofiber aerogel carrier was soaked in the impregnation solution at room temperature for 24 h (volume ratio of silica nanofiber aerogel to impregnation solution = 1:1), and the water was dried after the soaking treatment;

[0063] (2) Preparation of desulfurizer precursor: the silica nanofiber aerogel carrier after the soaking treatment in step (1) was sequentially soaked in 3 mmol / L KNO3 solution, NaF solution, and NaCl solution at room temperature for 24 h, and the water was dried after each soaking treatment to obtain a desulfurizer precursor;

[0064] (3) Preparation of high-efficiency regenerable coal gas desulfurizer: the desulfurizer precursor obtained in step (2) was subjected to microwave low-temperature calcination in a mixed gas with an oxygen concentration of 15 vol% (15 vol% oxygen + 85 vol% nitrogen) at a microwave power of 2500 W, the low-temperature calcination temperature was 240℃, and the calcination time was 2 h, the active component ZnFe2O4 was generated in the silica nanofiber aerogel carrier, and a high-efficiency regenerable coal gas desulfurizer (ZnFe2O4 content in the desulfurizer was 62.0 wt%) was obtained.

[0065] The desulfurizer prepared in this example (0.1 g) was placed in a fixed bed reaction device, and the desulfurization reaction was carried out at 500℃ under an air speed of 2000 h -1 The desulfurization reaction was carried out under the same conditions as above, and the desulfurizer was regenerated for 3 h under the same regeneration conditions as above.

[0066] After the desulfurization reaction, the sulfur capacity of the desulfurizer reached 33.21%, and the active component utilization rate was 99.99%.

[0067] Then, the mixed gas with an oxygen volume concentration of 2 vol% (2 vol% oxygen + 98 vol% nitrogen) was used, the temperature was 450℃, the air speed was 2000 h -1 The desulfurizer was regenerated for 3 h under the same regeneration conditions as above, and the regenerated desulfurizer was continuously used for the desulfurization reaction of the Texaco simulated coal gas under the same desulfurization reaction conditions as above.

[0068] After ten sulfurization / regeneration cycles, the regeneration rate of the desulfurizer was 97%, the sulfur capacity was 33.93%, and the active component utilization rate was 99.99%.

[0069] Example 4

[0070] A preparation method of a coal gas desulfurizer capable of efficient regeneration, comprising the following steps:

[0071] (1) Metal ion impregnation: 2.97 g of a precursor of an active component ZnFe2O4, specifically Zn(NO3)2·6H2O, 0.01 mol, and 8.08 g of Fe(NO3)3·9H2O, 0.02 mol, are dissolved in 100 mL of water to obtain a mixed solution of zinc nitrate and iron nitrate as an impregnation solution; the silica nanofiber aerogel carrier is soaked in the impregnation solution at room temperature for 24 h (by volume ratio, silica nanofiber aerogel: impregnation solution = 1:1), and the water is dried after the soaking treatment;

[0072] (2) Preparation of a desulfurizer precursor: the silica nanofiber aerogel carrier after the soaking treatment in step (1) is sequentially soaked in 4 mmol / L KNO3 solution, NaF solution and NaCl solution at room temperature for 24 h, and the water is dried after each soaking treatment, to obtain a desulfurizer precursor;

[0073] (3) Preparation of a coal gas desulfurizer capable of efficient regeneration: the desulfurizer precursor obtained in step (2) is subjected to microwave low-temperature calcination in a mixed gas with an oxygen concentration of 20 vol% (20 vol% oxygen + 80 vol% nitrogen) at a microwave power of 3000 W, the low-temperature calcination temperature is 240℃, and the calcination time is 2 h, to generate the active component ZnFe2O4 in the silica nanofiber aerogel carrier, thereby obtaining a coal gas desulfurizer capable of efficient regeneration (the content of ZnFe2O4 in the desulfurizer is 62.0 wt%).

[0074] The desulfurizer prepared in this embodiment (0.1 g) is placed in a fixed bed reaction device, and the desulfurization reaction is carried out at 500℃ under a space velocity of 2000 h -1 The Texaco simulated coal gas is introduced, and the desulfurization reaction is carried out at 500℃ until saturation absorption is achieved.

[0075] After the desulfurization reaction is completed, the sulfur capacity of the desulfurizer reaches 27.99%, and the utilization rate of the active component is 90.23%.

[0076] Then, the mixed gas with an oxygen concentration of 2 vol% (2 vol% oxygen + 98 vol% nitrogen) is used for regeneration of the desulfurizer at a temperature of 450℃ and a space velocity of 2000 h -1 for 3 h, and the regenerated desulfurizer is obtained and continuously used for the desulfurization reaction of the Texaco simulated coal gas under the same conditions as above. The regeneration is carried out again under the same conditions.

[0077] After ten cycles of sulfurization / regeneration, the regeneration rate of the desulfurizer was 88%, the sulfur capacity was 24.93%, and the utilization rate of the active component was 82.77%.

[0078] Comparative Example 1

[0079] The purchased commercial ZnFe2O4 was used as the active component, and the ZnFe2O4 and the silica nanofiber aerogel were mechanically mixed at a certain mass ratio (62.0:38.0) to prepare the desulfurizer.

[0080] The specific operation of mechanical mixing was as follows: ZnFe2O4 was dispersed in water to prepare a ZnFe2O4 dispersion liquid with a concentration of 0.1 mol / L, the silica nanofiber aerogel was added, and the silica nanofiber aerogel was taken out after mechanical stirring for 3 h, and then dried to obtain the desulfurizer (the content of ZnFe2O4 in the desulfurizer was 62.0 wt%).

[0081] Under the same desulfurization reaction experimental conditions as in Example 1, the initial sulfur capacity of the mechanically mixed ZnFe2O4 / silica nanofiber aerogel desulfurizer prepared in this comparative example was 10.1%, and the utilization rate of the active component was 33.53%.

[0082] After desulfurization, regeneration was carried out under the same conditions as in Example 1, and after ten cycles of sulfurization / regeneration, the regeneration rate of the mechanically mixed ZnFe2O4 / silica nanofiber aerogel desulfurizer was 50.12%, the sulfur capacity decreased to 4.8%, and the utilization rate of the active component was 15.47%.

[0083] Comparative Example 2

[0084] The same as in Example 1, except that the operation of step (2) was as follows: the silica nanofiber aerogel carrier after soaking treatment in step (1) was sequentially soaked in an equal volume of 1 mmol / L KNO3 solution and NaCl solution for 24 h to obtain the desulfurizer precursor.

[0085] Under the same desulfurization reaction experimental conditions as in Example 1, the initial sulfur capacity of the desulfurizer prepared in this comparative example was 26.2%, and the utilization rate of the active component was 84.46%.

[0086] After desulfurization, regeneration was carried out under the same conditions as in Example 1, and after ten cycles of sulfurization / regeneration, the regeneration rate of the desulfurizer was 82.66%, the sulfur capacity decreased to 22.47%, and the utilization rate of the active component was 72.44%.

[0087] Comparative Example 3

[0088] The same as example 1, the difference is only that the operation of step (2) is that the silica nanofiber aerogel carrier after the immersion treatment of step (1) is sequentially immersed in equal volumes of 1 mmol / L NaF solution and NaCl solution for 24 h to obtain the desulfurizer precursor.

[0089] Under the same desulfurization reaction experimental conditions as example 1, the initial sulfur capacity of the desulfurizer prepared in this comparative example is 25.3%, and the active component utilization rate is 81.56%.

[0090] After desulfurization, regeneration is carried out under the same conditions as example 1, and after ten sulfurization / regeneration cycles, the regeneration rate of the desulfurizer is 81.02%, the sulfur capacity decreases to 20.38%, and the active component utilization rate is 65.70%.

[0091] Comparative example 4

[0092] The same as example 1, the difference is only that the heating method of step (3) is changed to a conventional heating method instead of microwave heating. The low-temperature calcination temperature is 240°C, and the calcination time is 2 h.

[0093] Under the same desulfurization reaction experimental conditions as example 1, the initial sulfur capacity of the desulfurizer prepared in this comparative example is 25.34%, and the active component utilization rate is 81.69%.

[0094] After desulfurization, regeneration is carried out under the same conditions as example 1, and after ten sulfurization / regeneration cycles, the regeneration rate of the desulfurizer is 80.63%, the sulfur capacity decreases to 20.11%, and the active component utilization rate is 64.83%.

[0095] Test example 1

[0096] The desulfurizer prepared in example 1 is taken for TEM characterization, and the TEM characterization graph is as shown in Figure 1 , wherein a, b, and c (the circled parts in b and c are metal ion defects) respectively represent graphs of different magnifications. As can be seen from the TEM characterization graph, Figure 1 , the desulfurizer contains a large number of metal ion vacancies.

[0097] The desulfurizer prepared in example 1 and the desulfurizer prepared in comparative example 1 are taken for EPR characterization, and the EPR characterization graphs of the two are as shown in Figure 2 , which shows the comparison of the oxygen vacancy concentrations of the two. As can be seen from the EPR characterization graph, the desulfurizer prepared in example 1 contains a large number of oxygen vacancies.

[0098] The desulfurizer prepared in example 1 is taken for TEM characterization after one desulfurization reaction, and the TEM characterization graph of the desulfurizer after the desulfurization reaction is as shown in Figure 3 , wherein a, b, and c (the circled parts in a and c are metal ion defects) respectively represent graphs of different magnifications. As can be seen from the TEM characterization graph,Figure 3 It can be seen that the desulfurizer after the desulfurization reaction still contains a large amount of metal ion vacancies.

[0099] The above-described embodiments are merely preferred modes of the present application and are not intended to limit the scope of the present application. Various modifications and improvements to the technical solutions of the present application made by those of ordinary skill in the art without departing from the design spirit of the present application shall fall within the protection scope of the present application as defined by the claims.

Claims

1. A method for preparing a highly efficient regenerable coal gas desulfurizing agent, characterized in that, Includes the following steps: The silica nanofiber aerogel carrier was sequentially immersed in a mixed solution of zinc nitrate and iron nitrate, a KNO3 solution, a NaF solution, and a NaCl solution to obtain a desulfurizing agent precursor. The desulfurizing agent precursor was then subjected to microwave low-temperature calcination to generate the active component ZnFe2O4 in the silica nanofiber aerogel carrier, thus obtaining the highly efficient regenerable coal gas desulfurizing agent.

2. The preparation method according to claim 1, characterized in that, The porosity of the silica nanofiber aerogel carrier is 95-99.99%, and the diameter of the silica nanofibers is 100-1000 nm.

3. The preparation method according to claim 1, characterized in that, The molar ratio of zinc nitrate to ferric nitrate in the mixed solution is 1:2, and the concentration of zinc nitrate is 0.1 mol / L.

4. The preparation method according to claim 1, characterized in that, The concentrations of the KNO3 solution, NaF solution, and NaCl solution are all 1-4 mmol / L.

5. The preparation method according to claim 1, characterized in that, During the soaking treatment, the volume ratio of the silica nanofiber aerogel carrier to the mixed solution of zinc nitrate and ferric nitrate, KNO3 solution, NaF solution, and NaCl solution was 1:1; the soaking time was 24 hours.

6. The preparation method according to claim 1, characterized in that, The specific parameters for microwave low-temperature calcination include: oxygen concentration of 5-20 vol%, microwave power of 1500-3000 W, calcination temperature of 240℃, and calcination time of 2 hours.

7. A highly efficient regenerable coal gas desulfurizer prepared by the preparation method according to any one of claims 1-6.

8. A method for regenerating the highly efficient regenerable coal gas desulfurizer as described in claim 7, characterized in that, Includes the following steps: Using a mixed gas with an oxygen concentration of 2 vol%, at a temperature of 450 °C for 2000 h... -1 The desulfurizing agent for coal gas that has undergone desulfurization reaction is regenerated at a space velocity of 0.5 to obtain the regenerated coal gas desulfurizing agent.

9. The regeneration method as described in claim 8, characterized in that, The specific operation of the desulfurization reaction is as follows: A highly efficient regenerable coal gas desulfurizing agent is placed in a fixed-bed reactor at a reaction time of 2000 h⁻¹. -1 Gas is introduced at air velocity and desulfurization reaction is carried out at 500℃.

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