A fuel oil denitrification agent and a method for preparing the same

Abstract

This invention belongs to the field of catalyst technology, specifically relating to a fuel denitrifying agent and its preparation method, comprising the following steps: S1 Preparing a mixed solution using a silicon source, an aluminum source, and an alkali; impregnating a support with the mixed solution until the liquid is completely absorbed; S2 Vacuum evaporating the impregnated support to obtain a denitrifying agent precursor; S3 Microwave treating the denitrifying agent precursor in a sealed environment, followed by ammonium exchange and calcination to obtain the fuel denitrifying agent; This denitrifying agent is suitable for removing large molecular base nitrogen such as pyridine and its derivatives, quinoline and its derivatives, etc. from fuel.

Description

Technical Field

[0001] This invention belongs to the field of catalyst technology, specifically relating to a fuel denitrification agent and its preparation method. Background Technology

[0002] Fuel oils such as kerosene, gasoline, and diesel, as well as coal processing byproducts such as light coal tar, contain a certain amount of organic nitrogen compounds. Industrially, these are generally treated by hydrodenitrogenation. However, existing hydrodenitrogenation technologies struggle to remove nitrogen compounds to the ppm level or below. The remaining organic nitrogen compounds are typically basic nitrogen compounds, such as pyridine and its derivatives, and quinoline and its derivatives. These organic nitrogen compounds have complex structures and are extremely stable. Further processing with hydrodenitrogenation would require high-pressure hydrogen and could easily lead to excessive hydrogenation of olefins and aromatics in the fuel oil, resulting in a loss of calorific value, such as octane number. If the remaining ppm level of organic nitrogen compounds is not removed, it can cause deterioration of the fuel oil during storage and damage downstream catalysts, such as poisoning and deactivation of catalytic cracking catalysts.

[0003] Adsorption is a suitable method for removing trace amounts of organic nitrogen compounds, especially basic nitrogen compounds, including pyridine and its derivatives, and quinoline and its derivatives. Chinese invention patent application CN 1194074C discloses a method for removing nitrogen oxides from lubricating oil using a mixture of phosphoric acid, sulfuric acid, and organic acids, followed by refining with activated clay. Its disadvantages include difficulty in mixing and separating the mixed acids from the lubricating oil, and the potential for secondary pollution. Chinese invention patent application CN 1155682C discloses a method for modifying activated clay with inorganic acids such as sulfuric acid and phosphoric acid, and their salts such as sulfates and phosphates of copper and iron, which can be used for the adsorption and removal of alkaline nitrogen from fuel. This method also suffers from the problem of dissolving and separating inorganic acids and their salts in fuel. Chinese invention patent applications CN 101555417B and CN 101869830B disclose a silica-alumina mixture adsorbent prepared from silica sol and alumina sol, which is claimed to effectively remove alkaline nitrogen with a nitrogen adsorption capacity of 2.1-2.2%. However, after the adsorbent becomes saturated, it requires the use of organic solvents such as ethyl acetate and methyl isobutyl ketone to dissolve the alkaline nitrogen and regenerate it, making the process complex. (Chinese invention patent application CN 1194074C) Chinese invention patent application CN 117920133A discloses a Y-type molecular sieve modified with zinc oxide, iron oxide, and lanthanide metal oxides, which can be used for the adsorption and removal of basic nitrogen from benzene. Its basic nitrogen adsorption capacity is approximately 1%. Due to the large size of basic nitrogen molecules, their diffusion within the pores of the Y-type molecular sieve is limited. Especially after basic nitrogen is adsorbed at the pore openings, other basic nitrogen molecules have difficulty entering the interior of the molecular sieve pores, resulting in a low adsorption capacity. Given the limitations of the existing technology, it is necessary to develop a novel fuel basic nitrogen adsorbent to meet market demand. Summary of the Invention

[0004] To address the shortcomings of the existing technology, this invention provides a fuel denitrifying agent and its preparation method, which can effectively improve the alkaline nitrogen adsorption capacity and significantly enhance the purification degree.

[0005] The specific plan is as follows:

[0006] A fuel denitrifying agent includes a carrier and a loaded aluminosilicate; the aluminosilicate is 5wt% to 40wt% of the fuel denitrifying agent by mass; the aluminosilicate has a silicon-to-aluminum ratio of SiO2 / Al2O3 of (1 to 10):1.

[0007] Preferably, the carrier is alumina or silicon dioxide with an average pore size ≥40nm, and is spherical, strip-shaped, sheet-shaped, or Raschig ring-shaped.

[0008] A method for preparing a fuel denitrification agent includes the following steps:

[0009] S1. A mixed solution is prepared using a silicon source, an aluminum source, and an alkali; the carrier is then impregnated with the mixed solution until the liquid is completely absorbed.

[0010] S2 The impregnated carrier is vacuum evaporated to obtain a denitrifying agent precursor;

[0011] S3 The denitrifying agent precursor is microwave-treated in a closed environment, and then obtained by ammonium exchange and calcination to obtain the fuel denitrifying agent.

[0012] The silicon source is preferably at least one of sodium metasilicate, sodium orthosilicate, silica sol, and ethyl orthosilicate; the aluminum source is preferably at least one of sodium aluminate, aluminum sol, aluminum sulfate, aluminum nitrate, and aluminum chloride; and the alkali source is preferably at least one of sodium hydroxide, sodium carbonate, potassium hydroxide, and potassium carbonate.

[0013] Further, in step S1, the molar ratio of Na2O or K2O, SiO2, Al2O3, and H2O in the mixed solution is (1~15):(1~8):1:(10~100). This invention, by controlling the raw material ratio, can subsequently obtain aluminosilicates with different configurations, such as type A molecular sieves like type 4A molecular sieve aluminosilicates, octahedral zeolite molecular sieves like type X molecular sieve aluminosilicates, and type Y molecular sieve aluminosilicates; for example, when the molar ratio of n(Na2O):n(SiO2):n(Al2O3):n(H2O) varies within the range of (1~5):(1~3):1:(10~50), type 4A molecular sieve aluminosilicates can be prepared; when... When the molar ratio of n(Na2O):n(SiO2):n(Al2O3):n(H2O) varies in the range of (1~5):(2~4):1:(10~50), 13X-type molecular sieve aluminosilicates can be prepared; when the molar ratio of n(Na2O):n(SiO2):n(Al2O3):n(H2O) varies in the range of (5~15):(3~8):1:(20~100), Y-type molecular sieve aluminosilicates can be prepared.

[0014] Preferably, in step S1, the impregnation ratio of the carrier to the mixed solution is (1~5) g: 1 mL.

[0015] Furthermore, in step S2, the vacuum evaporation temperature is 20~90℃, the vacuum evaporation pressure is <50KPa, and the vacuum evaporation time is 1~10h. Through vacuum evaporation under low pressure conditions, 20wt%~90wt% of the water in the carrier is evaporated, forming a thin layer of molecular sieve precursor liquid film on the pore wall of the carrier.

[0016] Furthermore, in step S3, the microwave treatment temperature is 80~200℃, the microwave treatment time is 0.5~10h, and the microwave treatment power is 200~1000W. By microwave treatment at a certain temperature for a period of time, a film-like aluminosilicate with a silicon-to-aluminum ratio of SiO2 / Al2O3 of (1~10):1 is formed on the pore walls of the carrier.

[0017] Preferably, in step S3, the ammonium exchange is performed using 0.1~5 mol / L ammonium salt at 20~80℃ for 1~20 h; the ammonium salt is preferably a soluble ammonium salt, such as ammonium nitrate, ammonium chloride, or ammonium sulfate.

[0018] Preferably, in step S3, the calcination temperature is 400~600℃ and the calcination time is 1~20h.

[0019] Compared with existing technologies, the beneficial effects are as follows:

[0020] This invention uses macroporous alumina and silica as carriers and employs an in-situ microwave hydrothermal synthesis method to generate a thin-film molecular sieve-like membrane on the pore walls of the carrier. A hydrogen-type molecular sieve membrane is then prepared through ammonium exchange and calcination. This denitrifying agent is suitable for removing large molecular basic nitrogen, such as pyridine and its derivatives, quinoline and its derivatives, from fuel oil. It reduces the diffusion distance of basic nitrogen within the molecular sieve channels, increases its effective utilization rate, and thus improves the adsorption capacity of basic nitrogen. Furthermore, using a macroporous carrier reduces the diffusion resistance of materials within the adsorbent particles, making it easier for basic nitrogen to reach the molecular sieve pores, minimizing the proportion of basic nitrogen passing between adsorbent particles, and improving the purification degree of basic nitrogen. Detailed Implementation

[0021] The embodiments of the present invention will be described in further detail below. The following examples are for illustrative purposes only and should not be construed as limiting the scope of the invention. Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0022] Example 1

[0023] A method for preparing a fuel denitrification agent includes the following steps:

[0024] Weigh 15g of sodium metasilicate (Na2SiO3), 13.4g of sodium aluminate (NaAlO2), and 8.2g of sodium hydroxide (NaOH), and dissolve them in 45mL of deionized water to obtain a mixed solution. Weigh 65g of strip-shaped macroporous alumina (γ-Al2O3) with an average pore size ≥40nm and place it in a beaker. Pour the mixed solution into the beaker and impregnate until the liquid is completely absorbed. Then, place the impregnated alumina support in a three-necked flask, heat it in a water bath to 60℃, and evacuate it to 30kPa using a vacuum pump. After evaporating approximately 20g of water over 5 hours, a denitrifying agent precursor was obtained. The three-necked flask containing the precursor was then sealed and placed in a microwave generator with a water bath. It was irradiated at 90°C with 300W microwaves for 2 hours to obtain a material with a thin film of aluminosilicate loaded on the pore walls of the carrier. Finally, the material was washed three times with deionized water until neutral, and then exchanged twice with 400mL of 1mol / L ammonium nitrate (NH4NO3) solution at 60°C for 1 hour, followed by three washes with deionized water. After drying at 110°C for 10 hours, it was calcined at 500°C for 5 hours to obtain the denitrifying agent. The denitrifying agent contained 19.5wt% loaded aluminosilicate (hydrogen form) with a silicon-to-aluminum ratio (SiO2 / Al2O3) of 1.5:1, a composition similar to that of hydrogen-form 4A molecular sieves.

[0025] Example 2

[0026] A method for preparing a fuel denitrification agent includes the following steps:

[0027] Weigh 26g of sodium metasilicate (Na2SiO3), 13.4g of sodium aluminate (NaAlO2), and 7.1g of sodium hydroxide (NaOH) and dissolve them in 45mL of deionized water to obtain a mixed solution. Weigh 65g of strip-shaped macroporous alumina (γ-Al2O3) with an average pore size ≥40nm and place it in a beaker. Pour the mixed solution into the beaker and impregnate until the liquid is completely absorbed. Then, place the impregnated alumina support in a three-necked flask, heat it in a water bath to 80℃, and evacuate it to 30kPa using a vacuum pump. After evaporating approximately 25g of water over 2 hours, a denitrifying agent precursor was obtained. The three-necked flask containing the precursor was then sealed and placed in a microwave generator with a water bath. It was irradiated at 80°C with 300W microwaves for 3 hours to obtain a material with a thin film of aluminosilicate loaded on the pore walls of the carrier. The material was then washed three times with deionized water until neutral. It was then exchanged twice with 400mL of 1mol / L ammonium nitrate (NH4NO3) solution at 60°C for 1 hour, followed by three washes with deionized water. After drying at 110°C for 10 hours, it was calcined at 550°C for 4 hours to obtain the denitrifying agent. The denitrifying agent contained 24.5wt% loaded aluminosilicate (hydrogen form) and had a silicon-to-aluminum ratio (SiO2 / Al2O3) of 2.6:1, with a composition similar to that of hydrogen-form 13X molecular sieves.

[0028] Example 3

[0029] Weigh 20g of sodium metasilicate (Na2SiO3), 6.7g of sodium aluminate (NaAlO2), and 13.1g of sodium hydroxide (NaOH) and dissolve them in 45mL of deionized water to obtain a mixed solution. Weigh 65g of strip-shaped macroporous alumina (γ-Al2O3) with an average pore size ≥40nm and place it in a beaker. Pour the mixed solution into the beaker and impregnate until the liquid is completely absorbed. Then, place the impregnated alumina support in a three-necked flask, heat it in a water bath to 70℃, and evacuate it to 30kPa using a vacuum pump. The denitrifying agent precursor was obtained by evaporating approximately 20g of water over 3.5 hours. The three-necked flask containing the precursor was then sealed and placed in a microwave generator with a water bath. It was irradiated at 90°C with 300W microwaves for 3 hours to obtain a material with a thin film of aluminosilicate loaded on the pore walls of the carrier. The material was then washed three times with deionized water until neutral, and exchanged twice with 400mL of 1mol / L ammonium nitrate (NH4NO3) solution at 60°C for 1 hour, followed by three washes with deionized water. After drying at 110°C for 10 hours, it was calcined at 500°C for 6 hours to obtain the denitrifying agent. The denitrifying agent contained 17.7wt% loaded aluminosilicate (hydrogen form) and had a silicon-to-aluminum ratio (SiO2 / Al2O3) of 4.0:1, a composition similar to that of HY molecular sieves.

[0030] Comparative Example 1

[0031] Weigh 100g of 4A molecular sieve raw powder (Na2O·Al2O3·1.5SiO2·4.5H2O), exchange it with 500mL of 1mol / L ammonium nitrate (NH4NO3) solution at 60℃ for 1h, repeat the exchange twice, and wash it three times with deionized water; then dry the exchanged molecular sieve at 110℃ for 10h, and then mix it evenly with 15g of pseudoboehmite powder; weigh 20g of alumina sol with an Al2O3 content of 20wt%, mix it evenly with 30mL of deionized water and add it to the above powder, knead it with a kneader for 30 minutes, extrude it into strips with a diameter of φ3~4mm, then dry it at 110℃ for 10h, and calcine it at 500℃ for 5h to obtain a denitrifying agent; wherein, the 4A molecular sieve (hydrogen form) content is 80wt%, and the silicon-aluminum ratio (SiO2 / Al2O3) is equal to 1.5:1.

[0032] Comparative Example 2

[0033] Weigh 100g of 13X molecular sieve raw powder (Na2O·Al2O3·2.6SiO2·6H2O), exchange it with 500mL of 1mol / L ammonium nitrate (NH4NO3) solution at 60℃ for 1h, repeat the exchange twice, and wash it three times with deionized water; dry the exchanged molecular sieve at 110℃ for 10h, and then mix it evenly with 18g of pseudoboehmite powder; weigh 20g of alumina sol with an Al2O3 content of 20wt%, mix it evenly with 30mL of deionized water and add it to the above powder, knead it with a kneader for 30 minutes, extrude it into strips with a diameter of φ3~4mm, then dry it at 110℃ for 10h, and calcine it at 550℃ for 4h to obtain a denitrifying agent; wherein, the 13X molecular sieve (hydrogen form) content is 80wt%, and the silicon-aluminum ratio (SiO2 / Al2O3) is equal to 2.6:1.

[0034] Comparative Example 3

[0035] 100g of NaY molecular sieve raw powder (Na2O·Al2O3·4.0SiO2·5H2O) was weighed and exchanged with 500mL of 1mol / L ammonium nitrate (NH4NO3) solution at 60℃ for 1h, and the exchange was repeated twice. The sieve was then washed three times with deionized water. The exchanged molecular sieve was dried at 110℃ for 10h and then mixed evenly with 20g of pseudoboehmite powder. 20g of alumina sol with an Al2O3 content of 20wt% was weighed and mixed evenly with 30mL of deionized water and added to the above powder. The mixture was kneaded for 30 minutes using a kneader, extruded into strips with a diameter of 3~4mm, dried at 110℃ for 10h, and calcined at 500℃ for 6h to obtain a denitrifying agent. The HY type molecular sieve content was 80wt%, and the silicon-aluminum ratio (SiO2 / Al2O3) was equal to 4.0:1.

[0036] test

[0037] The denitrifying agents prepared in Examples 1-3 and Comparative Examples 1-3 of this invention were applied to the adsorption and removal of quinoline from kerosene in a fixed-bed reactor. The denitrifying agent dosage was 10 g, the liquid feed rate was 200 g / h, the pressure was normal, the adsorption temperature was 50°C, and the quinoline content was 100 ppm (equivalent to a nitrogen content of 10.8 ppm). Samples were taken hourly to analyze the composition of the effluent, and the nitrogen content was detected using a sulfur-nitrogen analyzer. When the quinoline content exceeded 1 ppm, the bed was considered to have broken through, and the experiment was terminated. The experimental results are shown in Table 1.

[0038] Table 1. Denitrification performance test results

[0039]

[0040] Although the molecular sieve content in Comparative Examples 1-3 was significantly higher than that in Examples 1-3, the above data shows that the nitrogen capacity of the denitrifying agent of the present invention is still significantly better than that of the denitrifying agent prepared in the comparative examples.

[0041] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A fuel oil denitrification agent, characterized by comprising: The aluminosilicate includes a carrier and the aluminosilicate loaded thereon; the aluminosilicate is 5wt% to 40wt% of the mass of the fuel denitrifying agent; the silicon-to-aluminum ratio (SiO2 / Al2O3) of the aluminosilicate is (1 to 10):

1.

2. The fuel denitrification agent according to claim 1, characterized in that, The carrier is alumina or silicon oxide with an average pore size ≥40nm.

3. The method for preparing the fuel denitrifying agent according to claim 1, characterized in that, Includes the following steps: S1. A mixed solution is prepared using a silicon source, an aluminum source, and an alkali; the carrier is then impregnated with the mixed solution until the liquid is completely absorbed. S2 The impregnated carrier is vacuum evaporated to obtain a denitrifying agent precursor; S3 The denitrifying agent precursor is microwave-treated in a closed environment, and then obtained by ammonium exchange and calcination to obtain the fuel denitrifying agent.

4. The preparation method according to claim 3, characterized in that, In step S1, the molar ratio of Na2O or K2O, SiO2, Al2O3, and H2O in the mixed solution is (1~15):(1~8):1:(10~100).

5. The preparation method according to claim 3, characterized in that, In step S1, the silicon source is at least one of sodium metasilicate, sodium orthosilicate, silica sol, and ethyl orthosilicate; the aluminum source is at least one of sodium aluminate, aluminum sol, aluminum sulfate, aluminum nitrate, and aluminum chloride; and the alkali source is at least one of sodium hydroxide, sodium carbonate, potassium hydroxide, and potassium carbonate.

6. The preparation method according to claim 3, characterized in that, In step S2, the vacuum evaporation temperature is 20~90℃, the vacuum evaporation pressure is <50KPa, and the vacuum evaporation time is 1~10h.

7. The preparation method according to claim 3, characterized in that, In step S3, the microwave treatment temperature is 80~200℃, the microwave treatment time is 0.5~10h, and the microwave treatment power is 200~1000W.

8. The preparation method according to claim 3, characterized in that, In step S3, the calcination temperature is 400~600℃ and the calcination time is 1~20h.

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