Hydrogenation polycyclic aromatic hydrocarbon removal catalyst as well as preparation method and application thereof

Abstract

The invention provides a preparation method of a hydrogenation polycyclic aromatic hydrocarbon removal catalyst. The preparation method comprises the following steps: (1) dissolving a salt precursor of a metal additive M and an organic ligand in a solvent to obtain a mixed solution; dispersing an inorganic refractory oxide into the mixture, and performing solvent heat treatment to obtain a composite carrier; loading the hydrogenation active metal onto the carrier, and heating in an inert atmosphere to activate the hydrogenation catalyst; the hydrogenation polycyclic aromatic hydrocarbon removal catalyst is obtained. The metal additive M is fixed on the carrier in an in-situ growth manner, so that more uniform dispersion can be realized, the acid property on the surface of the catalyst is improved, the adjustment of the subsequent additive on the interaction between the metal and the carrier is facilitated, the specific surface area of the carrier can be effectively increased, and the subsequent loading of active metal components is facilitated; meanwhile, the organic frame structure on the surface can also separate the active metal, sintering and agglomeration of the active metal in the subsequent activation and vulcanization process are reduced, the dispersity of the active component is improved, the size of the active phase is reduced, and the utilization rate of the active metal is increased.

Description

Technical Field

[0001] This invention relates to the field of hydrogenation technology, specifically to a method for preparing and applying a catalyst for the hydrogenation of polycyclic aromatic hydrocarbons. Background Technology

[0002] With the increasing deterioration of crude oil quality and increasingly stringent environmental regulations, the requirements for hydrotreating technology are also rising. New diesel standards also impose stricter quality requirements on diesel products. As one of the most effective processes for improving fuel quality, a highly efficient hydrotreating catalyst is an indispensable element of hydrotreating technology.

[0003] CN1169336A discloses a catalyst for the hydrorefining of distillate oil, which is modified by a mixture of alumina powders with different pore sizes containing fluorine, and then impregnated with a Ni-W metal solution. The catalyst has good application performance, but the pore size distribution range of the two powders used in this catalyst is relatively wide, which is not conducive to achieving optimal utilization of active metals and mass diffusion.

[0004] CN108246341A discloses a method for preparing and using a hydrodearomatization catalyst. In this invention, a nickel-phosphorus solution is first prepared, and then impregnated onto supports with large specific surface areas such as MCM-41, MCM-48, SBA-15, and SiO2 using an initial impregnation method. After drying, calcination, hydrogen reduction, and passivation, a catalyst precursor is obtained. Trimethylaluminum is then deposited on the precursor using atomic deposition, followed by calcination to obtain the hydrodearomatization catalyst. This catalyst exhibits high activity and selectivity in the fixed-bed saturated hydrogenation of naphthalene to decahydronaphthalene. However, the deposition of trimethylaluminum in this invention may alter pore properties, hindering the adsorption and diffusion of large aromatic molecules. Furthermore, the use of high-silica supports, such as strongly acidic molecular sieves, can easily lead to cracking reactions, resulting in reduced liquid yield.

[0005] Existing technologies still have some shortcomings, making it difficult to balance hydrogenation saturation and desulfurization performance, resulting in different catalyst activities and selectivity that make it difficult for them to function effectively. Summary of the Invention

[0006] To improve the activity and selectivity of hydrorefining catalysts, this invention provides a hydrorefining catalyst for polycyclic aromatic hydrocarbons (PAHs). The catalyst support is modified with MOF material, enabling one-step adjustment of pore and acid properties, and rapid modification and control of catalyst surface properties and active phase. This method is highly operable, and the prepared catalyst, after activation, exhibits excellent activity and selectivity, ensuring efficient desulfurization and denitrification while improving the selective hydrogenation performance of PAHs and reducing hydrogen consumption. It is suitable for diesel fuel quality upgrading processes.

[0007] To solve the above technical problems, the technical solution of the present invention is as follows:

[0008] The first aspect of this invention provides a method for preparing a hydrogenation dehydrocarbonization catalyst, comprising:

[0009] (1) Dissolve the salt precursor and organic ligand of metal auxiliary M in a solvent respectively, and after complete dissolution, mix them evenly to obtain a mixed solution;

[0010] (2) Disperse the inorganic refractory oxide into the mixed solution of step (1), perform solvothermal treatment, filter, wash and dry the product to obtain the composite carrier;

[0011] (3) Load the hydrogenated active metal onto the composite support of step (2), dry it, and obtain the catalyst precursor;

[0012] (4) Under an inert atmosphere, the catalyst precursor of step (3) is heated to activate the hydrogenation catalyst; the hydrogenation depolycyclic aromatic hydrocarbon catalyst is obtained.

[0013] Furthermore, the metal additive M mentioned in step (1) is selected from at least one of Zr, Ti, Cu, Cr and Cd, preferably at least one of Zr and Ti.

[0014] Further, the organic ligand in step (1) is selected from at least one of benzoic acid, terephthalic acid, pyromellitic acid, pyromellitic tetracarboxylic acid, 2-amino-terephthalic acid, 4-carboxyphenylporphyrin, fumaric acid, 2,2'-bipyridine-5,5'-dicarboxylic acid, 2-sulfonic acid-terephthalic acid, 4,4'-stilbene dicarboxylic acid, adenine, 2-mercaptosuccinic acid, and 4,4'-biphenyl dicarboxylic acid, preferably at least one of 2-mercaptosuccinic acid, 2,2'-bipyridine-5,5'-dicarboxylic acid, 2-amino-terephthalic acid, and 2-sulfonic acid-terephthalic acid.

[0015] Furthermore, the solvent in step (1) is selected from at least one of water, methanol, ethanol, formic acid, acetic acid and N,N-dimethylformamide, preferably at least one of ethanol and N,N-dimethylformamide.

[0016] Furthermore, in step (1), the molar ratio of the organic ligand to the metal auxiliary M is 0.1-10:1, preferably 0.5-6:1.

[0017] Furthermore, the inorganic refractory oxide mentioned in step (2) is selected from at least one of silicon dioxide, alumina, amorphous silica-alumina, SBA-15, Y molecular sieve and β molecular sieve, preferably at least one of amorphous silica-alumina, alumina and β molecular sieve.

[0018] Furthermore, in step (2), the proportion of the inorganic refractory oxide added is 80-99.5% based on the total weight of the inorganic refractory oxide and the oxide of M, preferably 85-98%.

[0019] Furthermore, the dispersion method described in step (2) is ultrasonic treatment or mechanical stirring.

[0020] Furthermore, the temperature of the solvent heat treatment in step (2) is 30-200℃, preferably 50-160℃; the time is 0.5-50h, preferably 1-48h.

[0021] Furthermore, the drying temperature in step (2) is 60-200℃, preferably 80-150℃; the drying time is 1-20h, preferably 6-12h; and the drying method is oven drying or vacuum drying, preferably vacuum drying.

[0022] Further, the hydrogenation active metal mentioned in step (3) is at least one of Group VIII metals and at least one of Group VIB metals; wherein the Group VIII metal is selected from at least one of Fe, Co and Ni, preferably Co and / or Ni; the Group VIB metal is selected from at least one of Mo, W and Cr, preferably Mo and / or W. By weight, the oxidized Group VIII metal accounts for 1-20% of the total weight of the catalyst, preferably 2.8-12.5%; the oxidized Group VIB metal accounts for 10-45% of the total weight of the catalyst, preferably 15-40%.

[0023] Furthermore, in step (3), the hydrogenated active metal is loaded onto the composite support from step (2) using an impregnation method. The impregnation material is selected from vacuum rotary evaporation impregnation and equal-volume impregnation, preferably equal-volume impregnation. The raw material for the hydrogenated active metal is a metal salt; for Group VIII metals, the raw material is at least one of nitrates, chlorides, and acetates, preferably nitrates; for Group VIB metals, the raw material is preferably an ammonium salt.

[0024] Furthermore, the drying temperature in step (3) is 80-150℃, preferably 90-120℃; the drying time is 1-10h, preferably 3-6h.

[0025] Furthermore, the inert atmosphere in step (4) is at least one of nitrogen, argon, helium and carbon dioxide, preferably at least one of nitrogen and argon, the pressure of the inert atmosphere is 0.2-0.5 MPa, and the volumetric flow rate of the inert gas is 50-100 L / h.

[0026] Furthermore, the activation temperature in step (4) is 120-400℃, preferably 180-300℃; the activation time is 2-12h, preferably 3-6h.

[0027] A second aspect of the present invention provides a hydrogenation dehydrocarbon catalyst prepared by the above preparation method.

[0028] A third aspect of the present invention provides a method for the hydrorefining reaction of diesel fuel, wherein the above-mentioned hydrodehydropolycyclic aromatic hydrocarbon catalyst is reacted with diesel fuel.

[0029] Furthermore, during startup, the catalyst undergoes sulfidation. After activation, the temperature is adjusted to the sulfidation temperature, sulfidation oil is introduced, and hydrogen is introduced to increase the pressure, thus sulfiding the catalyst. The sulfidation oil consists of light oil and a sulfiding agent. The light oil refers to one or more types of gasoline or kerosene; the sulfiding agent is one or more types of carbon disulfide, methyl sulfide, dimethyl disulfide, and n-butyl sulfide.

[0030] Furthermore, the properties of the diesel fuel are as follows: sulfur content of 1.1-2.2 wt%, nitrogen content of 280-580 ug / g, aromatic content of 25-45 wt%, and polycyclic aromatic hydrocarbon content of 11-20 wt%.

[0031] Furthermore, the reaction conditions between the catalyst and the oil are as follows: reaction temperature 330-390℃, reaction pressure 4.5-8.5MPa, hydrogen-to-oil volume ratio 180-1000:1, and liquid hourly space velocity 0.3-6h. -1 .

[0032] The technical solution of the present invention has the following technical effects:

[0033] (1) In the preparation method of the hydrodehydropolycyclic aromatic hydrocarbon catalyst of the present invention, the metal promoter M is fixed on the support by in-situ growth, which can achieve more uniform dispersion, improve the acid properties of the catalyst surface, facilitate the subsequent regulation of the interaction between the metal and the support by the promoter, and effectively increase the specific surface area of ​​the support, which is beneficial to the subsequent loading of the active metal component; at the same time, the organic framework structure on the surface can also separate the active metal, reduce the sintering and agglomeration of the active metal in the subsequent activation and sulfidation process, improve the dispersion of the active component, reduce the size of the active phase, and improve the utilization rate of the active metal.

[0034] (2) During the preparation of the catalyst of the present invention, heating and activation under an inert atmosphere occurs, resulting in the pyrolysis of MOF groups on the catalyst to obtain carbon species. On the one hand, this can effectively activate the activity of the catalyst, protect the active phase, and prevent the growth and aggregation of the active phase at high temperatures during sulfidation and reaction, thus fully maximizing the activity of the catalyst. On the other hand, the carbon species can modify the electronic properties of the active phase, thereby stabilizing and modifying the active phase, improving the selectivity of the catalyst, and extending the service life of the catalyst. Detailed Implementation Plan

[0035] The present invention will be described in detail below through embodiments, but the present invention is not limited to these embodiments.

[0036] Example 1

[0037] (1) Dissolve 9.06g of zirconium nitrate pentahydrate in 60mL of ethanol, and dissolve 7.64g of 2-amino-terephthalic acid in 40mL of ethanol solvent. After complete dissolution, mix well to obtain a mixed solution.

[0038] (2) Disperse 20g of macroporous alumina into the mixed solution of step (1), stir mechanically for 20min, transfer to a hydrothermal reactor, and carry out a solvothermal reaction at 120℃ for 12h. Then, centrifuge the product, wash it with ethanol and water, and dry the solid in a vacuum drying oven at 100℃ for 5h to obtain the composite carrier;

[0039] (3) Dissolve 4.33g of nickel nitrate nonahydrate and 6.81g of ammonium molybdate heptahydrate in water, and impregnate them onto the composite support of step (2) using the equal volume impregnation method. Dry them at 110℃ for 6h to obtain the catalyst precursor.

[0040] (4) The catalyst precursor from step (3) was activated by heat treatment at 280°C for 3 hours under a nitrogen atmosphere to obtain hydrogenation dehydrocarbon catalyst A.

[0041] Example 2

[0042] (1) Dissolve 1.24g of zirconium nitrate pentahydrate in 60mL of ethanol, and dissolve 0.26g of 2-amino-terephthalic acid in 40mL of ethanol solvent. After complete dissolution, mix well to obtain a mixed solution.

[0043] (2) Disperse 20g of amorphous silica-alumina into the mixed solution of step (1), stir mechanically for 30min, transfer to a hydrothermal reactor, and carry out a solvothermal reaction at 80℃ for 6h. Then, centrifuge the product, wash with ethanol and water, and dry the solid in a vacuum drying oven at 100℃ for 5h to obtain the composite carrier;

[0044] (3) Dissolve 3.79g of nickel nitrate nonahydrate and 5.97g of ammonium molybdate heptahydrate in water, and impregnate them onto the composite support of step (2) using the equal volume impregnation method. Dry at 130℃ for 8h to obtain the catalyst precursor.

[0045] (4) The catalyst precursor from step (3) was activated by heat treatment at 400°C for 3 hours under a nitrogen atmosphere to obtain hydrogenation dehydrocarbon catalyst B.

[0046] Example 3

[0047] (1) Dissolve 12.61g of zirconium nitrate pentahydrate in 80mL of ethanol, and dissolve 1.06g of 2-amino-terephthalic acid in 40mL of ethanol solvent. After complete dissolution, mix well to obtain a mixed solution.

[0048] (2) Disperse 20g of amorphous silica-alumina into the mixed solution of step (1), stir mechanically for 30min, transfer to a hydrothermal reactor, and carry out a solvothermal reaction at 170℃ for 3h. Afterwards, centrifuge the product, wash with ethanol and water, and dry the solid in a drying oven at 100℃ for 3h to obtain the composite carrier;

[0049] (3) Dissolve 2.25g of nickel nitrate nonahydrate and 7.93g of ammonium molybdate heptahydrate in water, and impregnate them onto the composite support of step (2) using the equal volume impregnation method. Dry at 90℃ for 12h to obtain the catalyst precursor;

[0050] (4) The catalyst precursor from step (3) was activated by heat treatment at 300°C for 3 hours under a nitrogen atmosphere to obtain the hydrogenation dehydrocarbon catalyst C.

[0051] Example 4

[0052] (1) Dissolve 9.06g of zirconium nitrate pentahydrate in 60mL of ethanol, and dissolve 11.46g of 2-amino-terephthalic acid in 400mL of ethanol solvent. After complete dissolution, mix well to obtain a mixed solution.

[0053] (2) Disperse 20g of macroporous alumina into the mixed solution of step (1), stir mechanically for 30min, transfer to a hydrothermal reactor, and carry out a solvothermal reaction at 140℃ for 6h. Then, centrifuge the product, wash with ethanol and water, and dry the solid in a drying oven at 130℃ for 5h to obtain the composite carrier;

[0054] (3) Dissolve 4.33g of nickel nitrate nonahydrate and 11.72g of ammonium molybdate heptahydrate in water, and impregnate them onto the composite support of step (2) using the equal volume impregnation method. Dry at 85°C for 5 hours to obtain the catalyst precursor.

[0055] (4) The catalyst precursor from step (3) was activated by heat treatment at 350°C for 3 hours under a nitrogen atmosphere to obtain the hydrogenation dehydrocarbon catalyst D.

[0056] Comparative Example 1

[0057] Except for step (4), which involves heat treatment at 280°C for 3 hours in air, the other steps are the same as in Example 1. The resulting hydrorefining catalyst is denoted as E.

[0058] Comparative Example 2

[0059] (1) Dissolve 9.06g of zirconium nitrate pentahydrate in 60mL of ethanol, and dissolve 7.64g of 2-amino-terephthalic acid in 40mL of ethanol solvent. After complete dissolution, mix well to obtain a mixed solution.

[0060] (2) Place the mixed solution from step (1) in a hydrothermal reactor and carry out a solvothermal reaction at a temperature of 120°C for 12 hours. After the solvothermal reaction is completed, centrifuge the mixture in the hydrothermal reactor and then centrifuge the product. Wash the product with ethanol and water and dry the solid in a vacuum drying oven at 100°C for 5 hours. Collect the dried solid.

[0061] (3) Mix 20g of macroporous alumina with the solid obtained in step (2) to obtain the mixed carrier;

[0062] (4) Dissolve 4.33g of nickel nitrate nonahydrate and 6.81g of ammonium molybdate heptahydrate in water, and impregnate them onto the composite support of step (3) using the equal volume impregnation method. Dry them at 110℃ for 6h to obtain the catalyst precursor.

[0063] (5) The catalyst precursor from step (4) was activated by heat treatment at 280°C for 3 hours under a nitrogen atmosphere to obtain the hydrogenation dehydrocarbonization catalyst F.

[0064] Comparative Example 3

[0065] 4.33g of nickel nitrate nonahydrate, 6.81g of ammonium molybdate heptahydrate, and 7.74g of zirconium nitrate pentahydrate were dissolved in water and impregnated onto 20g of macroporous alumina using an equal-volume impregnation method. The mixture was dried at 110℃ for 6 hours and calcined at 400℃ for 5 hours to obtain hydrogenation refining catalyst G.

[0066] The properties of the catalysts prepared in the above examples and comparative examples are shown in Table 1. Specific surface area and pore volume were determined by nitrogen physical adsorption, and total acidity was determined by the NH3-TPD method using a chemisorption analyzer. The composition of the catalysts was determined by inorganic colorimetry, and the composition of the support was determined by X-ray fluorescence spectrometry.

[0067] Table 1

[0068]

[0069]

[0070] As can be seen from Table 1, the catalysts in the examples have larger pore volume and specific surface area than the comparative examples, and the total surface infrared acid content is also increased.

[0071] Example 5

[0072] The performance of the catalyst in diesel hydrorefining:

[0073] The activated catalyst was loaded into a laboratory fixed-bed reactor for reaction. The raw material was a blended diesel fuel from a refinery. The catalyst was sulfided using an in-reactor sulfidation reaction.

[0074] Catalyst sulfidation conditions: 2 wt% CS2 jet fuel as sulfiding oil, volumetric hourly space velocity 1.5 h⁻¹ -1 The hydrogen-to-oil volume ratio was 200, and the catalyst was sulfided under a pressure of 6.5 MPa. The heating program was as follows: the temperature was increased to 120°C at a rate of 1°C / min, and the sulfiding oil was introduced and held at this temperature for 4 hours; then the temperature was increased to 230°C at a rate of 1°C / min and held at this temperature for 10 hours; then the temperature was increased to 340°C at a rate of 1°C / min and held at this temperature for 7 hours to complete the sulfidation process.

[0075] Reaction conditions: operating pressure 6.8 MPa, reaction temperature 335℃, hydrogen-to-oil volume ratio 500, and volume hourly space velocity 1.0 h⁻¹. -1 The evaluation results of the properties of raw materials and products are shown in Table 2.

[0076] Table 2.

[0077]

[0078]

[0079] As can be seen from Table 2, the catalyst prepared in this invention exhibits excellent desulfurization and denitrification activity, while also demonstrating superior selective saturation activity for polycyclic aromatic hydrocarbons.

Claims

1. A method for preparing a catalyst for the hydrogenation of polycyclic aromatic hydrocarbons, comprising: (1) Dissolve the salt precursor and organic ligand of the metal auxiliary M in a solvent respectively. After complete dissolution, mix them evenly to obtain a mixed solution. (2) Disperse the inorganic refractory oxide into the mixed solution of step (1), perform solvothermal treatment, filter, wash and dry the product to obtain the composite carrier; (3) Load the hydrogenation active metal onto the composite support of step (2), dry it, and obtain the catalyst precursor; (4) Under an inert atmosphere, the catalyst precursor of step (3) is heated to activate the hydrogenation catalyst; the hydrogenation dehydrocarbonization catalyst is obtained.

2. The preparation method according to claim 1, characterized in that, The metal additive M mentioned in step (1) is selected from at least one of Zr, Ti, Cu, Cr and Cd.

3. The preparation method according to claim 1, characterized in that, The organic ligand in step (1) is selected from at least one of benzoic acid, terephthalic acid, pyromellitic acid, pyromellitic tetracarboxylic acid, 2-amino-terephthalic acid, 4-carboxyphenylporphyrin, fumaric acid, 2,2'-bipyridine-5,5'-dicarboxylic acid, 2-sulfonic acid-terephthalic acid, 4,4'-stilbene dicarboxylic acid, adenine, 2-mercaptosuccinic acid, and 4,4'-biphenyl dicarboxylic acid.

4. The preparation method according to claim 1, characterized in that, The solvent in step (1) is selected from at least one of water, methanol, ethanol, formic acid, acetic acid and N,N-dimethylformamide.

5. The preparation method according to claim 1, characterized in that, In step (1), the molar ratio of the organic ligand to the metal auxiliary M is 0.1-10:

1.

6. The preparation method according to claim 1, characterized in that, The inorganic refractory oxide mentioned in step (2) is selected from at least one of silica, alumina, amorphous silica-alumina, SBA-15, Y molecular sieve and β molecular sieve.

7. The preparation method according to claim 1, characterized in that, In step (2), the inorganic refractory oxide accounts for 80-99.5% of the total weight of the inorganic refractory oxide and the oxide of M.

8. The preparation method according to claim 1, characterized in that, The temperature of the solvent heat treatment in step (2) is 30-200℃ and the time is 0.5-50h.

9. The preparation method according to claim 1, characterized in that, The hydrogenation active metal mentioned in step (3) is at least one of Group VIII metals and at least one of Group VIB metals; wherein the Group VIII metal is selected from at least one of Fe, Co and Ni; the Group VIB metal is selected from at least one of Mo, W and Cr; by weight, the oxidized Group VIII metal accounts for 1-20% of the total weight of the catalyst; the oxidized Group VIB metal accounts for 10-45% of the total weight of the catalyst.

10. The preparation method according to claim 1, characterized in that, The inert atmosphere mentioned in step (4) is at least one of nitrogen, argon, helium and carbon dioxide, the pressure of the inert atmosphere is 0.2-0.5 MPa, and the volumetric flow rate of the inert gas is 50-100 L / h.

11. The preparation method according to claim 1, characterized in that, The activation temperature in step (4) is 120-400℃, and the activation time is 2-12h.

12. The hydrogenation dehydrocarbon catalyst prepared by the preparation method according to any one of claims 1-11.

13. A method for hydrorefining diesel fuel, comprising reacting diesel fuel with the hydrodehydrocarbonization catalyst of claim 12.

14. The method according to claim 1, characterized in that, The properties of the diesel fuel feedstock are as follows: sulfur content 1.1-2.2 wt%, nitrogen content 280-580 ug / g, aromatic content 25-45 wt%, and polycyclic aromatic hydrocarbon content 11-20 wt%. The reaction conditions between the catalyst and the fuel are as follows: reaction temperature 330-390℃, reaction pressure 4.5-8.5 MPa, hydrogen-to-oil volume ratio 180-1000:1, and liquid hourly space velocity 0.3-6 h⁻¹. -1 .

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