A blast furnace gas desulfurization adsorbent, a preparation method and application thereof

Abstract

This invention belongs to the technical field of adsorbents for gas adsorption and separation, and more specifically relates to a blast furnace gas desulfurization adsorbent, its preparation method, and its application. The blast furnace gas desulfurization adsorbent provided by this invention, by mass percentage, comprises: 70-80% rare earth FAU-type zeolite molecular sieve, 15-25% binder, and binding aids. This blast furnace gas desulfurization adsorbent can efficiently remove H2S from blast furnace gas and inhibit COS formation during adsorption. It has high sulfur capacity, good resistance to poisoning, and thermal stability. Furthermore, the preparation method is simple, cost-controllable, and recyclable.

Description

Technical Field

[0001] This invention belongs to the technical field of adsorbents for gas adsorption and separation, and more specifically relates to a blast furnace gas desulfurization adsorbent, its preparation method, and its application. Background Technology

[0002] The steel industry's production process generates a large amount of byproduct gas. Blast furnace gas (BFG) is the largest byproduct gas produced during ironmaking, with approximately 1500-2000 m³ produced per ton of pig iron smelted. 3 Blast furnace gas. Its main components are N2 (50%-60%), CO (19%-30%), CO2 (15%-20%), and H2 (0.5%-2.5%), and it also contains small amounts of sulfides (mainly H2S, with inorganic sulfur accounting for more than 80%) and chlorides, among other impurities. It is used as a low-calorific-value fuel (calorific value approximately 3000-3500 kJ / m³). 3 After dust removal and purification, blast furnace gas is widely used in hot blast stoves, steel rolling heating furnaces, boiler power generation and other scenarios, which is a key link for steel enterprises to achieve energy self-sufficiency and energy conservation and emission reduction.

[0003] However, sulfides (H2S, COS, etc.) present in blast furnace gas are converted into SO2 during combustion, causing severe air pollution and corroding downstream pipelines and equipment, becoming a core bottleneck restricting its clean and efficient utilization. COS in blast furnace gas can be easily converted into H2S through a relatively mature catalytic hydrolysis reaction; therefore, developing efficient H2S removal technology is key to achieving sufficient and necessary deep desulfurization of blast furnace gas.

[0004] In the existing desulfurization technology system, although wet desulfurization can efficiently remove H2S, its process is complex, requires large equipment investment, generates wastewater and waste liquid, and needs to operate at relatively low temperatures, making it difficult to match the waste heat utilization requirements of blast furnace gas. In contrast, dry adsorption desulfurization, due to its simple process, no wastewater discharge, wide operational flexibility, and recyclable adsorbent, exhibits unique application advantages under medium-temperature conditions.

[0005] Existing adsorbents have the following technical drawbacks: (1) Low sulfur capacity: The working sulfur capacity of the adsorbent is limited, resulting in high replacement frequency and high operating cost.

[0006] (2) Desulfurization: During the adsorption process, H2S will be converted into COS, resulting in secondary pollution.

[0007] (3) Poor regeneration performance: It is difficult to regenerate effectively after adsorption saturation, and has poor economic efficiency.

[0008] Therefore, developing a blast furnace gas desulfurization adsorbent that can efficiently remove H2S and suppress its side reactions, has high sulfur capacity, and is regenerable is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0009] The purpose of this invention is to provide a blast furnace gas desulfurization adsorbent, its preparation method, and its application. Specifically, it provides a zeolite molecular sieve adsorbent for removing H2S from blast furnace gas and its preparation method, in order to solve the problems existing in the prior art.

[0010] To achieve the above objectives, the present invention provides the following solution: One of the technical solutions of this invention: provides a blast furnace gas desulfurization adsorbent, the raw materials of which, by mass percentage, include: Rare earth FAU type zeolite molecular sieve 70-80%, binder 15-25%, and binder aid 2-5%; The rare earth FAU type zeolite molecular sieve is a LaCe composite rare earth Y type molecular sieve.

[0011] Furthermore, the La / Ce ratio (molar ratio) in the LaCe composite rare earth Y-type molecular sieve is 0.3-11.

[0012] Furthermore, the binder includes at least one of bentonite, attapulgite, and kaolin.

[0013] Furthermore, the adhesive additive includes at least one of guar gum powder, methylcellulose, and polyethylene glycol.

[0014] The second technical solution of the present invention provides a method for preparing the above-mentioned blast furnace gas desulfurization adsorbent, the steps of which include: Rare earth FAU type zeolite molecular sieve, binder and binding aid are dry-mixed evenly, the moisture content is adjusted to 35-40%, and after molding, it is dried and calcined to obtain the blast furnace gas desulfurization adsorbent.

[0015] Furthermore, the forming process involves kneading followed by extrusion forming or roll forming.

[0016] Furthermore, the drying temperature is 100-120℃, and the time is 1-3 hours.

[0017] Preferably, the drying temperature is 110°C and the drying time is 2 hours.

[0018] Furthermore, the heating rate of the calcination is 1-3℃ / min, the temperature is 500-600℃, and the holding time is 1-3h.

[0019] Preferably, the heating rate of the calcination is 2°C / min, and the holding time is 2h.

[0020] The third technical solution of the present invention provides an application of the above-mentioned blast furnace gas desulfurization adsorbent in blast furnace gas desulfurization treatment.

[0021] The present invention discloses the following technical effects: The blast furnace gas desulfurization adsorbent provided by this invention can efficiently remove H2S from blast furnace gas and inhibit the generation of COS during the adsorption process. It has high sulfur capacity, good anti-poisoning ability and thermal stability. Moreover, the preparation method is simple, the cost is controllable, and it can be recycled.

[0022] The blast furnace gas desulfurization adsorbent provided by this invention has a sulfur penetration capacity of 2.61 mg S / g for H2S and a COS conversion rate as low as 1.23%. Furthermore, the adsorbent, after adsorption saturation, can be completely regenerated at 600 °C under an inert gas atmosphere. It can be used in industrial applications for dry H2S removal from blast furnace gas.

[0023] The blast furnace gas desulfurization adsorbent provided by this invention has desulfurization performance and regeneration characteristics derived from the regulation of the acid-base properties of the zeolite surface. The sulfur penetration capacity is positively correlated with the total acid content. The conversion and release of COS during adsorption are related to the amount of weak alkali. The regeneration performance is limited by the amount of strong alkali. A relatively low amount of strong alkali allows the adsorbent after adsorption saturation to be completely regenerated in an inert gas atmosphere at 600°C. Attached Figure Description

[0024] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings: Figure 1 The image shows the XRD patterns of the cerium-rich Y zeolite molecular sieve and adsorbent 1 in Example 1.

[0025] Figure 2 The N2 adsorption / desorption isotherm of cerium-rich Y zeolite molecular sieve and adsorbent 1 in Example 1 is shown.

[0026] Figure 3 The image shows the surface elemental surface scan analysis of adsorbent 1.

[0027] Figure 4 The NH3-TPD fitting curves of the cerium-rich Y zeolite molecular sieve and adsorbent 1 in Example 1 are shown.

[0028] Figure 5 The image shows the CO2-TPD fitting curves of the cerium-rich Y zeolite molecular sieve and adsorbent 1 in Example 1.

[0029] Figure 6 The H2S-TPD curves of the cerium-rich Y zeolite molecular sieve and adsorbent in Example 1, which is the adsorption saturation test, under a nitrogen atmosphere. Detailed Implementation

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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 readily apparent to those skilled in the art. This specification and embodiments are merely exemplary.

[0034] 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.

[0035] Unless otherwise specified, all raw materials and reagents involved in the specific embodiments of this invention are commercially available products.

[0036] Unless otherwise specified, room temperature and ambient temperature in the specific embodiments of this invention refer to 20-30℃.

[0037] It should be noted that any aspects not described in detail in this invention are conventional practices in the field and are not the focus of this invention.

[0038] Example 1 The preparation steps of the blast furnace gas desulfurization adsorbent include: S1. Prepare the following raw materials according to the following mass percentage: 75% cerium-rich Y zeolite molecular sieve (La / Ce ratio of 0.52), 20% attapulgite, and 5% guar gum powder.

[0039] S2. After mixing the cerium-rich Y zeolite molecular sieve and attapulgite evenly, add guar gum powder and stir evenly to obtain dry mix.

[0040] S3. Adjust the moisture content of the dry mix to 40%, knead and then extrude to form strips to obtain the adsorbent product.

[0041] S4. The adsorbent product is dried in an oven at 110 ℃ for 2 h, and then heated to 550 ℃ in a muffle furnace at a heating rate of 2 ℃ / min and calcined at a constant temperature for 2 h to obtain the blast furnace gas desulfurization adsorbent, which is denoted as adsorbent 1.

[0042] Example 2 The preparation steps of the blast furnace gas desulfurization adsorbent include: S1. Prepare the following raw materials according to the following mass percentage: It contains 75% cerium-rich Y zeolite molecular sieve (La / Ce ratio of 0.46), 20% bentonite, and 5% guar gum powder.

[0043] S2. After mixing the cerium-rich Y zeolite molecular sieve and bentonite evenly, add guar gum powder and stir evenly to obtain the dry mixture.

[0044] S3. Adjust the moisture content of the dry mix to 37%, knead and then extrude to form strips to obtain the adsorbent product.

[0045] S4. The adsorbent product is dried in an oven at 110 ℃ for 2 h, and then heated to 550 ℃ in a muffle furnace at a heating rate of 2 ℃ / min and calcined at a constant temperature for 2 h to obtain the blast furnace gas desulfurization adsorbent, which is denoted as adsorbent 2.

[0046] Example 3 The preparation steps of the blast furnace gas desulfurization adsorbent include: S1. Prepare the following raw materials according to the following mass percentage: It contains 75% cerium-rich Y zeolite molecular sieve (La / Ce ratio of 0.36), 20% kaolin and 5% guar gum powder.

[0047] S2. After mixing the cerium-rich Y zeolite molecular sieve and kaolin evenly, add guar gum powder and stir evenly to obtain the dry mixture.

[0048] S3. Adjust the moisture content of the dry mix to 38%, knead and then extrude to form strips to obtain the adsorbent product.

[0049] S4. The adsorbent product is dried in an oven at 110 ℃ for 2 h, and then heated to 600 ℃ in a muffle furnace at a heating rate of 2 ℃ / min and calcined at a constant temperature for 2 h to obtain the blast furnace gas desulfurization adsorbent, which is denoted as adsorbent 3.

[0050] Example 4 The preparation steps of the blast furnace gas desulfurization adsorbent include: S1. Prepare the following raw materials according to the following mass percentage: It contains 75% lanthanum-rich Y-zeolite molecular sieve (La / Ce ratio of 9.3), 20% attapulgite, and 5% guar gum powder.

[0051] S2. After mixing the lanthanum-rich Y zeolite molecular sieve and attapulgite evenly, add guar gum powder and stir evenly to obtain a dry mixture.

[0052] S3. Adjust the moisture content of the dry mix to 40%, knead and then extrude to form strips to obtain the adsorbent product.

[0053] S4. The adsorbent product is dried in an oven at 110 ℃ for 2 h, and then heated to 550 ℃ in a muffle furnace at a heating rate of 2 ℃ / min and calcined at a constant temperature for 2 h to obtain the blast furnace gas desulfurization adsorbent, which is designated as adsorbent 4.

[0054] Example 5 The preparation steps of the blast furnace gas desulfurization adsorbent include: S1. Prepare the following raw materials according to the following mass percentage: It contains 75% lanthanum-rich Y zeolite molecular sieve (La / Ce ratio of 10.9), 20% bentonite, and 5% guar gum powder.

[0055] S2. After mixing the lanthanum-rich Y zeolite molecular sieve and bentonite evenly, add guar gum powder and stir evenly to obtain a dry mixture.

[0056] S3. Adjust the moisture content of the dry mix to 38%, knead and then extrude to form strips to obtain the adsorbent product.

[0057] S4. The adsorbent product is dried in an oven at 110 ℃ for 2 h, and then heated to 550 ℃ in a muffle furnace at a heating rate of 2 ℃ / min and calcined at a constant temperature for 2 h to obtain the blast furnace gas desulfurization adsorbent, which is designated as adsorbent 5.

[0058] Example 6 The preparation steps of the blast furnace gas desulfurization adsorbent include: S1. Prepare the following raw materials according to the following mass percentage: It contains 75% lanthanum-rich Y zeolite molecular sieve (La / Ce ratio of 10.2), 20% kaolin, and 5% guar gum powder.

[0059] S2. After mixing the lanthanum-rich Y zeolite molecular sieve and kaolin evenly, add guar gum powder and stir evenly to obtain a dry mixture.

[0060] S3. Adjust the moisture content of the dry mix to 35%, knead and then extrude to form strips to obtain the adsorbent product.

[0061] S4. The adsorbent product is dried in an oven at 110 ℃ for 2 h, and then heated to 600 ℃ in a muffle furnace at a heating rate of 2 ℃ / min and calcined at a constant temperature for 2 h to obtain the blast furnace gas desulfurization adsorbent, which is designated as adsorbent 6.

[0062] Comparative Example 1 Cerium-rich Y zeolite molecular sieve (La / Ce ratio of 0.4) was heated to 550 °C in a muffle furnace at a heating rate of 2 °C / min and calcined at the same temperature for 2 h to obtain the calcined control adsorbent 1.

[0063] Comparative Example 2 Lanthanum-rich Y zeolite molecular sieve (La / Ce ratio of 11) was heated to 550 °C in a muffle furnace at a heating rate of 2 °C / min and calcined at the same temperature for 2 h to obtain the calcined control adsorbent 2.

[0064] Comparative Example 3 Pure cerium Y zeolite molecular sieve was heated to 550 °C in a muffle furnace at a heating rate of 2 °C / min and calcined at the same temperature for 2 h to obtain the calcined control adsorbent 3.

[0065] Comparative Example 4 Pure lanthanum Y zeolite molecular sieve was heated to 550 °C in a muffle furnace at a heating rate of 2 °C / min and calcined at the same temperature for 2 h to obtain the calcined control adsorbent 4.

[0066] Test case Figure 1 The XRD patterns of the cerium-rich Y zeolite molecular sieve and adsorbent 1 in Example 1 are shown in the figure. As can be seen from the figure, their spectra... Figure 1 All diffraction peaks exhibited characteristic diffraction peaks at 2θ = 23.64°, corresponding to the (533) crystal plane of FAU-type zeolite. This is one of the important characteristic diffraction peaks of the FAU structure and is closely related to the structural stability of the zeolite. The intensity of the diffraction peaks corresponding to the (533) crystal plane remained basically unchanged. This result indicates that the forming process and subsequent calcination treatment did not damage the framework structure of the zeolite, and the FAU-type topology was completely preserved.

[0067] Figure 2 The N2 adsorption / desorption isotherm of cerium-rich Y zeolite molecular sieve and adsorbent 1 in Example 1 is shown.

[0068] The hole structure parameters are shown in Table 1.

[0069] Table 1. Pore structure parameters of cerium-rich Y zeolite molecular sieve and adsorbent 1 From Table 1 and Figure 2 It can be seen that during the molding process, the introduction of binder leads to a decrease in the specific surface area and micropore volume of zeolite, but at the same time promotes the development of mesopores.

[0070] Figure 3 The image shows the surface elemental surface scan analysis of adsorbent 1. As can be seen from the image, adsorbent 1 mainly contains O, Si, Al, Na, La, and Ce. The O, Si, and Al elements are continuously and uniformly distributed with high overlap, forming the zeolite framework. The La and Ce elements are distributed in a manner consistent with the matrix, without obvious agglomeration or local enrichment, exhibiting a uniform dispersion. These results confirm that the rare earth active components have excellent dispersion on the zeolite surface, without clogging the pores, providing abundant active centers and mass transfer channels for H2S adsorption.

[0071] Figure 4 The NH3-TPD fitting curves of the cerium-rich Y zeolite molecular sieve and adsorbent 1 in Example 1 are shown.

[0072] The acidity distribution is shown in Table 2.

[0073] Table 2. Acidity of Cerium-Rich Y Zeolite Molecular Sieves and Adsorbent 1 Depend on Figure 4 As shown in Table 2, compared with cerium-rich Y zeolite molecular sieves, the acidity of adsorbent 1 decreased. The acid strength of weak and medium-strong acids did not change significantly, while the acid strength of strong acids increased significantly and the acidity of strong acids decreased. It has been proven that acidity is the key factor determining the H2S adsorption capacity of zeolite, so the sulfur penetration capacity of adsorbent 1 also decreased, but it still reached more than 80% of that of the main material, indicating that the molding process did not reduce the H2S adsorption performance of the material.

[0074] Figure 5 The image shows the CO2-TPD fitting curves of the cerium-rich Y zeolite molecular sieve and adsorbent 1 in Example 1.

[0075] The alkalinity distribution is shown in Table 3.

[0076] Table 3. Alkalinity of Cerium-Rich Y Zeolite Molecular Sieves and Adsorbent 1 Depend on Figure 5As shown in Table 3, compared with cerium-rich Y zeolite molecular sieves, the total alkali content increased, the weak alkali and medium-strong alkali content increased, and the strong alkali content decreased, indicating that the molding process altered the alkalinity distribution. The COS conversion rate was related to the weak alkali content, while the regeneration efficiency was limited by the strong alkali content. Reducing the strong alkali content through molding improved the regeneration efficiency.

[0077] Figure 6 The figure shows the H2S-TPD curves of the cerium-rich Y zeolite molecular sieve and adsorbent under a nitrogen atmosphere in Example 1, where the adsorption was saturated. As can be seen from the figure, H2S can be completely desorbed at 300℃, and the amount of H2S desorbed is positively correlated with the total acid content.

[0078] The desulfurization adsorbents prepared in the embodiments and comparative examples of this invention were tested for desulfurization performance under a simulated blast furnace gas atmosphere. The specific composition of the simulated blast furnace gas is shown in Table 4.

[0079] Table 4 Take 10.77 cm 3 The adsorbent prepared according to the examples or comparative examples was loaded into a fixed-bed reactor, and simulated blast furnace gas (H2S inlet concentration 300 ppm, temperature 60°C, space velocity 1000 h⁻¹) was introduced. −1 The test was run continuously, and the results are shown in Table 5.

[0080] Table 5 Table 5 shows that, during the adsorption process, the adsorbent provided by the present invention has a sulfur penetration capacity of H2S of more than 1.80 mg S / g, and can reach up to 2.61 mg S / g; the COS conversion rate is as low as about 5%, with the best being 1.23%.

[0081] The adsorbents of Examples 1-6 and Comparative Examples 1-2, after being saturated with adsorption, were heated to 600 °C under a N2 atmosphere for thermal regeneration. The initial adsorption capacity recovery rate of the regenerated adsorbents was tested again for desulfurization, as shown in Table 6.

[0082] Table 6 The data in Table 6 show that the adsorbent prepared by this invention can be completely regenerated in an inert gas atmosphere at 600 °C.

[0083] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0084] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A blast furnace gas desulfurization adsorbent, characterized in that, By weight percentage, the raw materials include: Rare earth FAU type zeolite molecular sieve 70-80%, binder 15-25%, and binder aid 2-5%; The rare earth FAU type zeolite molecular sieve is a LaCe composite rare earth Y type molecular sieve.

2. The blast furnace gas desulfurization adsorbent as described in claim 1, characterized in that, The La / Ce ratio in the LaCe composite rare earth Y-type molecular sieve is 0.3-11.

3. The blast furnace gas desulfurization adsorbent as described in claim 1, characterized in that, The binder includes at least one of bentonite, attapulgite, and kaolin.

4. The blast furnace gas desulfurization adsorbent as described in claim 1, characterized in that, The adhesive agent includes at least one of guar gum powder, methylcellulose, and polyethylene glycol.

5. A method for preparing a blast furnace gas desulfurization adsorbent according to any one of claims 1-4, characterized in that the step... include: Rare earth FAU type zeolite molecular sieve, binder and binding aid are dry-mixed evenly, the moisture content is adjusted to 35-40%, and after molding, it is dried and calcined to obtain the blast furnace gas desulfurization adsorbent.

6. The preparation method according to claim 5, characterized in that, The drying temperature is 100-120℃, and the time is 1-3 hours.

7. The preparation method according to claim 6, characterized in that, The drying temperature is 110℃ and the time is 2 hours.

8. The preparation method according to claim 5, characterized in that, The calcination heating rate is 1-3℃ / min, the temperature is 500-600℃, and the holding time is 1-3h.

9. The preparation method according to claim 8, characterized in that, The calcination heating rate is 2℃ / min, and the holding time is 2h.

10. The application of the blast furnace gas desulfurization adsorbent according to any one of claims 1-4 in the desulfurization treatment of blast furnace gas.

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