阅读说明：本技术 一种加氢脱硫催化剂及其制备方法 (Hydrodesulfurization catalyst and preparation method thereof ) 是由 隋宝宽 季洪海 彭冲 吕振辉 于 2019-04-17 设计创作，主要内容包括：本发明公开了一种加氢脱硫催化剂及其制备方法。该催化剂包括改性氧化铝基载体、钼和钨金属组分,所述改性氧化铝基载体含有镍和钴金属组分,所述改性氧化铝基载体包括主体改性氧化铝和棒状改性氧化铝,所述的主体改性氧化铝为具有微米级孔道的改性氧化铝,其中至少部分棒状改性氧化铝分布在主体改性氧化铝的外表面和孔直径D为3-7μm的微米级孔道中。该加氢脱硫催化剂用于渣油加氢反应时,具有较高的加氢脱硫活性和加氢脱残炭活性。(The invention discloses a hydrodesulfurization catalyst and a preparation method thereof. The catalyst comprises a modified alumina-based carrier, molybdenum and tungsten metal components, wherein the modified alumina-based carrier contains nickel and cobalt metal components, the modified alumina-based carrier comprises main modified alumina and rod-shaped modified alumina, the main modified alumina is modified alumina with micron-sized pore channels, and at least part of the rod-shaped modified alumina is distributed on the outer surface of the main modified alumina and the micron-sized pore channels with the pore diameter D of 3-7 mu m. The hydrodesulfurization catalyst has high hydrodesulfurization activity and hydrodecarbonization activity when being used for residual oil hydrogenation reaction.)

1. A hydrodesulfurization catalyst comprises a modified alumina-based carrier, molybdenum and tungsten metal components, wherein the modified alumina-based carrier contains nickel and cobalt metal components, the modified alumina-based carrier comprises main modified alumina and rod-shaped modified alumina, the main modified alumina is modified alumina with micron-sized pore channels, and at least part of the rod-shaped modified alumina is distributed on the outer surface of the main modified alumina and the micron-sized pore channels with the pore diameter D of 3-7 mu m.

2. The catalyst of claim 1, wherein: the total content of the nickel and cobalt metal components, calculated as oxides, is from 1% to 8%, preferably from 2% to 5%, based on the weight of the catalyst; the total content of the molybdenum and tungsten metal components is 10-20%, preferably 12-15% calculated by oxide.

3. A catalyst according to claim 1 or 2, characterized in that: the weight ratio of nickel to cobalt is 1:1-5:1 calculated by oxide; the weight ratio of molybdenum to tungsten is 3:1-8: 1.

4. The catalyst of claim 1, wherein: the rodlike modified alumina is basically distributed on the outer surface of the main body modified alumina and in the micron-sized pore channels.

5. The catalyst of claim 1, wherein: the length of the rod-shaped modified alumina in the micron-sized pore channel is mainly 0.3D-0.9D, and the length of the rod-shaped modified alumina on the outer surface is mainly 3-8 μm.

6. The catalyst of claim 1, wherein: the diameter of the rod-shaped modified alumina is 80-260 nm.

7. The catalyst of claim 1, wherein: in the modified alumina-based carrier, at least one end of at least part of rod-shaped modified alumina is attached to the micron-sized pore channel wall of the main modified alumina, preferably at least one end of at least part of rod-shaped modified alumina is combined with the micron-sized pore channel wall to form a whole with the main modified alumina, and further preferably at least one end of the rod-shaped modified alumina in the micron-sized pore channel is combined with the micron-sized pore channel wall to form a whole with the main modified alumina.

8. The catalyst of claim 1, wherein: in the modified alumina-based carrier, one end of at least part of the rod-shaped modified alumina is attached to the outer surface of the main modified alumina, preferably, one end of at least part of the rod-shaped modified alumina is bonded to the outer surface of the main modified alumina, and the other end of the rod-shaped modified alumina extends outwards and is integrated with the main modified alumina, and further preferably, one end of the rod-shaped modified alumina on the outer surface of the main modified alumina is bonded to the outer surface of the main modified alumina, and the other end of the rod-shaped modified alumina extends outwards and is integrated with the main modified alumina.

9. The catalyst of claim 1, wherein: the coverage rate of the rod-shaped modified alumina in the micron-sized pore channel of the main body modified alumina is 70-95%, and the coverage rate of the rod-shaped modified alumina on the outer surface of the main body modified alumina is 70-95%.

10. The catalyst of claim 1, wherein: the properties of the catalyst are as follows: the specific surface area is 190-²(iv)/g, pore volume of 0.8-1.6mL/g, crush strength of 10-20N/mm.

11. The catalyst of claim 1, wherein: the pores formed by the rod-shaped modified alumina staggered with each other in a random order are concentrated between 100-600 nm.

12. The catalyst of claim 1, wherein: the pore distribution of the catalyst is as follows: the pore volume of the pores with the pore diameter of less than 10nm accounts for less than 15 percent of the total pore volume, the pore volume of the pores with the pore diameter of 10-30nm accounts for 40-65 percent of the total pore volume, the pore volume of the pores with the pore diameter of 100-600nm accounts for 15-25 percent of the total pore volume, and the pore volume of the pores with the pore diameter of more than 1000nm accounts for less than 5 percent of the total pore volume.

13. A process for the preparation of a hydrodesulphurisation catalyst according to any of the claims 1-12 comprising:

(1) kneading and molding a physical pore-expanding agent, a pseudo-boehmite, a nickel and cobalt metal component source, drying and roasting to obtain an intermediate;

(2) immersing the intermediate obtained in the step (1) into an ammonium bicarbonate solution, then carrying out sealing heat treatment, drying and roasting the heat-treated material to obtain a modified alumina-based carrier;

(3) and (3) dipping the modified alumina-based carrier obtained in the step (2) in a solution containing molybdenum and tungsten metal components, drying and roasting to obtain the hydrodesulfurization catalyst.

14. The method of claim 13, wherein: the physical pore-enlarging agent in the step (1) is one or more of activated carbon and sawdust, the particle size of the physical pore-enlarging agent is 3-7 mu m, and the addition amount of the physical pore-enlarging agent is 10-20 wt% of the weight of the intermediate.

15. The method of claim 13, wherein: the nickel and cobalt metal component source in the step (1) is metal salt containing nickel and cobalt, wherein the metal salt containing nickel is one or two of nickel nitrate and basic nickel carbonate, and the metal salt containing cobalt is one or two of cobalt nitrate and basic cobalt carbonate.

16. The method of claim 13, wherein: the drying temperature in the step (1) is 80-160 ℃, the drying time is 6-10 hours, the roasting temperature is 650-750 ℃, and the roasting time is 4-6 hours.

17. The method of claim 13, wherein: the mass ratio of the using amount of the ammonium bicarbonate solution in the step (2) to the intermediate added in the step (2) is 4:1-7:1, and the mass concentration of the ammonium bicarbonate solution is 15% -25%.

18. The method of claim 13, wherein: the sealing heat treatment temperature in the step (2) is 120-160 ℃, the constant temperature treatment time is 4-8 hours, and the heating rate is 5-20 ℃/min.

19. A method according to claim 13 or 18, characterized by: and (2) performing sealing pretreatment before sealing heat treatment, wherein the pretreatment temperature is 60-100 ℃, the constant temperature treatment time is 2-4 hours, the temperature rise rate before the pretreatment is 10-20 ℃/min, the temperature rise rate after the pretreatment is 5-10 ℃/min, and the temperature rise rate after the pretreatment is at least 3 ℃/min lower than that before the pretreatment, preferably at least 5 ℃/min lower.

20. The method of claim 13, wherein: the drying temperature in the step (2) is 80-160 ℃, and the drying time is 6-10 hours; the roasting temperature in the step (2) is 550-750 ℃, and the roasting time is 4-6 hours.

21. The method of claim 13, wherein: the solution containing molybdenum and tungsten metal components in the step (3) is an aqueous solution containing molybdenum salt and tungsten salt, the molybdenum salt is ammonium molybdate, and the tungsten salt is ammonium tungstate.

22. The method of claim 13, wherein: the roasting temperature in the step (3) is 450-550 ℃, and the roasting time is 4-6 hours.

Technical Field

The invention relates to the field of catalyst preparation, in particular to a hydrodesulfurization catalyst and a preparation method thereof.

Background

With the increasing weight and quality of petroleum, petroleum processing is more and more difficult. Heavy oil residues contain a large amount of sulfur, most of which is present in asphaltenes, and are difficult to remove. Hydrodesulfurization has been regarded as an important process in petroleum refining and synthetic ammonia production using petroleum as a raw material. However, in recent years, the quality of petroleum is getting heavier and worse, the requirements on the quality of products are stricter, and the requirements on the feeding materials in the subsequent process are more and more strict. In addition, since the 21 st century, people's awareness of environmental protection has been increasing, and environmental legislation has become stricter and stricter, and NO in exhaust gas discharged from motor vehicles_x、SO_xAnd the limitation of the aromatic content is more severe. In 2010, a sulfur content of less than 10 μ g/g was required. For the above reasons, hydrodesulfurization techniques for gasoline and diesel are moving toward the processing of high sulfur oils and the production of ultra-low sulfur clean petroleum fuels.

CN101890380B discloses a hydrodesulfurization catalyst and application thereof. The catalyst is used for desulfurization reaction in a residual oil fixed bed hydrogenation method, and simultaneously carries out demetalization reaction in the desulfurization process, and asphaltene micelles containing metal in residual oil can diffuse into the inside of a pore channel of the catalyst, so that the removed metal is uniformly deposited on the whole catalyst bed layer, the pore utilization rate is improved, and the long-period operation of the catalyst is kept. However, the preparation process of the catalyst is complex, the cost is high, and the hydrogenation and carbon residue removal performance of the catalyst needs to be further improved.

CN1123626C discloses a heavy oil and residual oil hydrotreating catalyst and a preparation method thereof, in particular to a heavy oil hydrodesulfurization catalyst and a preparation method thereof. The method adopts a cheap and environment-friendly titanium-containing aluminum hydroxide carrier, promotes metal dispersion through the kneading process of materials such as titanium-containing aluminum hydroxide and metal salts, and prepares the catalyst through extrusion molding and high-temperature activation after all the materials are kneaded into plastic bodies. The catalyst prepared by the method has small aperture, is not beneficial to the entry of residual oil reactant molecules, and in addition, the hydrogenation carbon residue removal activity of the catalyst needs to be further improved.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a hydrodesulfurization catalyst and a preparation method thereof. The hydrodesulfurization catalyst has high hydrodesulfurization activity and hydrodecarbonization activity when being used for residual oil hydrogenation reaction.

The invention provides a hydrodesulfurization catalyst, which comprises a modified alumina-based carrier, molybdenum and tungsten metal components, wherein the modified alumina-based carrier contains nickel and cobalt metal components, the modified alumina-based carrier comprises main modified alumina and rod-shaped modified alumina, the main modified alumina is modified alumina with micron-sized pore channels, and at least part of the rod-shaped modified alumina is distributed on the outer surface of the main modified alumina and the micron-sized pore channels with the pore diameter D of 3-7 mu m.

The micron-sized pore channels in the invention refer to micron-sized pore channels with the pore diameter of 3-7 μm.

The hydrodesulfurization catalyst of the invention comprises 1-8% of nickel and cobalt metal components, preferably 2-5% of nickel and cobalt metal components, calculated by oxides, based on the weight of the catalyst; the total content of the molybdenum and tungsten metal components is 10-20%, preferably 12-15% calculated by oxide.

Further, the weight ratio of nickel to cobalt is 1:1-5:1 calculated by oxide; in the hydrogenation active metal, the weight ratio of molybdenum to tungsten is 3:1-8:1 in terms of oxide.

In the modified alumina-based carrier, the rodlike modified alumina is basically distributed on the outer surface of the main modified alumina and in the micron-sized pore channels. The rod-shaped modified alumina distributed on the outer surface of the main body modified alumina and in the micron-sized pore channels accounts for more than 95 percent of the total weight of all the rod-shaped modified aluminas, and preferably more than 97 percent.

In the modified alumina-based carrier, the length of the rod-shaped modified alumina in the micron-sized pore channel is mainly 0.3D-0.9D (which is 0.3-0.9 time of the diameter of the micron-sized pore channel), namely the length of more than 85 percent of the rod-shaped modified alumina in the micropore is 0.3D-0.9D by weight; the length of the rod-shaped modified alumina on the outer surface is mainly 3-8 μm, namely, the length of more than 85 percent of the rod-shaped modified alumina on the outer surface is 3-8 μm.

The diameter of the rod-shaped modified alumina is 80-260 nm.

In the modified alumina-based carrier, rod-shaped modified alumina is distributed in a disordered and mutually staggered state in micron-sized pore channels of main modified alumina.

In the modified alumina-based carrier of the present invention, at least one end of at least a part of the rod-shaped modified alumina is attached to the micron-sized pore wall of the main body modified alumina, and preferably, at least one end of at least a part of the rod-shaped modified alumina is bonded to the micron-sized pore wall to be integrated with the main body modified alumina. Further preferably, at least one end of the rod-like modified alumina in the micron-sized pore channel is bonded to the wall of the micron-sized pore channel, and is integrated with the main body of the modified alumina.

In the modified alumina-based carrier of the present invention, rod-like modified aluminas are distributed in a disordered and mutually staggered state on the outer surface of the main body modified alumina.

In the modified alumina-based carrier of the present invention, one end of at least a part of the rod-shaped modified alumina is attached to the outer surface of the main modified alumina, and preferably, one end of at least a part of the rod-shaped modified alumina is bonded to the outer surface of the main modified alumina, and the other end thereof protrudes outward and is integrated with the main modified alumina. Further preferably, one end of the rod-shaped modified alumina on the outer surface of the body modified alumina is bonded to the outer surface of the body modified alumina, and the other end thereof protrudes outward and is integrated with the body.

In the modified alumina-based carrier, the coverage rate of the rod-shaped modified alumina in the micron-sized pore canal of the main body modified alumina is 70-95%, wherein the coverage rate refers to the percentage of the surface of the inner surface of the micron-sized pore canal of the main body modified alumina, which is occupied by the rod-shaped modified alumina, in the inner surface of the micron-sized pore canal of the main body modified alumina. The coverage rate of the rod-shaped modified alumina on the outer surface of the main body modified alumina is 70-95%, wherein the coverage rate refers to the percentage of the surface occupied by the rod-shaped modified alumina on the outer surface of the main body modified alumina.

The properties of the hydrodesulfurization catalyst of the invention are as follows: the specific surface area is 190-²(iv)/g, pore volume of 0.8-1.6mL/g, crush strength of 10-20N/mm.

In the hydrodesulfurization catalyst, the pores formed by the disordered mutual interlacing of the rod-shaped modified alumina are concentrated between 100nm and 600 nm.

The pore distribution of the hydrodesulfurization catalyst of the invention is as follows: the pore volume of the pores with the pore diameter of less than 10nm accounts for less than 15 percent of the total pore volume, the pore volume of the pores with the pore diameter of 10-30nm accounts for 40-65 percent of the total pore volume, the pore volume of the pores with the pore diameter of 100-600nm accounts for 15-25 percent of the total pore volume, and the pore volume of the pores with the pore diameter of more than 1000nm accounts for less than 5 percent of the total pore volume.

The hydrodesulfurization catalyst of the present invention may further contain an auxiliary agent, such as one or more of phosphorus, boron, silicon, and the like. The weight content of the auxiliary agent in the catalyst is less than 10.0 percent, preferably 0.1 to 10.0 percent in terms of oxide.

In a second aspect, the present invention provides a method for preparing a hydrodesulfurization catalyst, comprising:

(1) kneading and molding a physical pore-expanding agent, a pseudo-boehmite, a nickel and cobalt metal component source, drying and roasting to obtain an intermediate;

(2) immersing the intermediate obtained in the step (1) into an ammonium bicarbonate solution, then carrying out sealing heat treatment, drying and roasting the heat-treated material to obtain a modified alumina-based carrier;

(3) and (3) dipping the modified alumina-based carrier obtained in the step (2) in a solution containing molybdenum and tungsten metal components, drying and roasting to obtain the hydrodesulfurization catalyst.

In the method, the physical pore-expanding agent in the step (1) can be one or more of activated carbon and sawdust, the particle size of the physical pore-expanding agent is about 3-7 mu m, and the addition amount of the physical pore-expanding agent is 10-20 wt% of the weight of the intermediate.

In the method, the nickel and cobalt metal component source in the step (1) is a metal salt containing nickel and cobalt, wherein the metal salt containing nickel is preferably one or two of nickel nitrate and basic nickel carbonate, and the metal salt containing cobalt is preferably one or two of cobalt nitrate and basic cobalt carbonate.

In the method of the present invention, the pseudoboehmite described in the step (1) may be a pseudoboehmite prepared by any method, for example, prepared by a precipitation method, an aluminum alkoxide hydrolysis method, an inorganic salt sol-gel method, a hydrothermal method, a vapor deposition method, and the like.

In the method, the kneading molding in the step (1) is carried out by adopting a conventional method in the field, and a proper amount of conventional molding aids, such as one or more of peptizing agents, extrusion aids and the like, can be added according to needs in the molding process. The peptizing agent is one or more of hydrochloric acid, nitric acid, sulfuric acid, acetic acid, oxalic acid and the like; the extrusion aid is sesbania powder.

The drying temperature in the step (1) is 80-160 ℃, the drying time is 6-10 hours, the roasting temperature is 650-750 ℃, and the roasting time is 4-6 hours; the calcination is carried out in an oxygen-containing atmosphere, preferably an air atmosphere. The intermediate may be in the form of a conventional alumina support, such as a sphere, having a particle size of typically 0.5-8.0mm, such as a bar, clover, etc., having a diameter of about 0.2-3.0mm and a length of about 0.5-8.0 mm.

In the method, the mass ratio of the using amount of the ammonium bicarbonate solution in the step (2) to the intermediate added in the step (2) is 4:1-7:1, and the mass concentration of the ammonium bicarbonate solution is 15-25%.

In the method of the invention, the sealing heat treatment temperature in the step (2) is 120-.

In the method, the step (2) is preferably carried out before the sealing heat treatment, the sealing pretreatment is carried out, the pretreatment temperature is 60-100 ℃, the constant temperature treatment time is 2-4 hours, the temperature rise rate before the pretreatment is 10-20 ℃/min, the temperature rise rate after the pretreatment is 5-10 ℃/min, and the temperature rise rate after the pretreatment is at least 3 ℃/min lower than that before the pretreatment, preferably at least 5 ℃/min lower.

In the method, the drying temperature in the step (2) is 80-160 ℃, and the drying time is 6-10 hours; the roasting temperature in the step (2) is 550-750 ℃, and the roasting time is 4-6 hours.

In the method of the present invention, the solution containing molybdenum and tungsten metal components in step (3) is an aqueous solution containing molybdenum salt and tungsten salt, the molybdenum salt is preferably ammonium molybdate, and the tungsten salt is preferably ammonium tungstate.

In the method of the present invention, the impregnation in the step (3) may be performed by a conventional impregnation method, and may be performed by an unsaturated impregnation method, a saturated impregnation method, or the like, preferably by a saturated impregnation method.

In the method, the roasting temperature in the step (3) is 450-550 ℃, and the roasting time is 4-6 hours.

Compared with the prior art, the invention has the following advantages:

1. the hydrodesulfurization catalyst of the invention fully utilizes the micron-scale pore canal of the main body modified alumina, rod-shaped alumina grows in the micron-scale pore canal, and the rod-shaped alumina is randomly and mutually distributed in a staggered manner, so that on one hand, the penetrability of the micron-scale pore canal is maintained, the specific surface area of the carrier is improved, the mechanical strength is enhanced, on the other hand, gas generated during roasting of the physical pore-expanding agent plays a certain role in expanding the pore of the nanometer-scale pore canal, the penetrability and the uniformity of the nanometer-scale pore canal are further promoted, and the diffusion capacity of reactant molecules is improved. Therefore, the hydrodesulfurization catalyst of the invention overcomes the problem that the large aperture, the specific surface area and the mechanical strength are not compatible due to the adoption of a physical pore-expanding agent.

2. One end of the surface rodlike alumina of the hydrodesulfurization catalyst is combined on the outer surface of the main alumina, and the other end of the surface rodlike alumina extends outwards.

3. According to the invention, the hydrogenation active metal components of nickel and cobalt and the hydrogenation active metal component auxiliaries of molybdenum and tungsten are introduced into the catalyst in two steps, firstly, the hydrogenation active component auxiliaries of nickel and cobalt are doped into the carrier, and the carrier is subjected to sealed hydrothermal treatment in an ammonium bicarbonate aqueous solution, so that the effects of the hydrogenation active component auxiliaries of nickel and cobalt and the carrier are effectively improved; on the other hand, the metal components added twice are different and are introduced into the catalyst in different modes, and further, by limiting the specific weight ratio among the metal components, the active components play a synergistic and complementary role, and the hydrodesulfurization activity and the hydrodecarbonization activity of the catalyst are improved.

4. In the process of preparing the carrier, the carrier is preferably pretreated at a certain temperature before sealing heat treatment, the pretreatment condition is relatively mild, and NH is slowly formed on the outer surface of the intermediate in the sealed, hydrothermal and mixed atmosphere of carbon dioxide and ammonia gas₄Al(OH)₂CO₃Crystal nuclei, raising the reaction temperature NH during the post-heat treatment₄Al(OH)₂CO₃The crystal nucleus continues to grow evenly to make rod-shaped NH₄Al(OH)₂CO₃Having uniform diameter and length while increasing rod-like NH₄Al(OH)₂CO₃Coverage on the outer surface of the alumina intermediate and the inner surface of the micron-sized pore channel. NH (NH)₄Al(OH)₂CO₃The gases such as ammonia gas and carbon dioxide generated during thermal decomposition play a good role in expanding the pore of the carrier intermediate again, so that the penetration and uniformity of the carrier pore are further promoted, and the diffusion capability of reactant molecules is improved.

5. The hydrodesulfurization catalyst has the characteristics of large aperture, large pore volume and strong pore passage connectivity, and is beneficial to mass transfer and diffusion of residual oil reactant molecules, so that the catalyst has high hydrodesulfurization and carbon residue removal activities.

Drawings

FIG. 1 is an SEM image of a modified alumina-based support prepared in example 1;

wherein the reference numbers are as follows: 1-main body modified alumina, 2-rod-shaped modified alumina and 3-micron pore canal.

Detailed Description

The following examples are provided to further illustrate the technical solutions of the present invention, but the present invention is not limited to the following examples. In the present invention, wt% is a mass fraction and v% is a volume fraction.

Application N₂Physical adsorption-desorption characterization of the pore structures of the catalysts in the examples and the comparative examples, the specific operations are as follows: adopting ASAP-2420 type N₂And the physical adsorption-desorption instrument is used for characterizing the pore structure of the sample. A small amount of samples are taken to be treated for 3 to 4 hours in vacuum at the temperature of 300 ℃, and finally, the product is placed under the condition of liquid nitrogen low temperature (-200 ℃) to be subjected to nitrogen absorption-desorption test. Wherein the specific surface area is obtained according to a BET equation, and the distribution rate of the pore volume and the pore diameter below 50nm is obtained according to a BJH model.

Mercury pressing method: the mercury porosimeter is used for representing the pore diameter distribution of the catalysts in the examples and the comparative examples, and the specific operation is as follows: and characterizing the distribution of sample holes by using an American microphone AutoPore9500 full-automatic mercury porosimeter. The samples were dried, weighed into an dilatometer, degassed for 30 minutes while maintaining the vacuum conditions given by the instrument, and filled with mercury. The dilatometer was then placed in the autoclave and vented. And then carrying out a voltage boosting and reducing test. The mercury contact angle is 130 degrees, and the mercury interfacial tension is 0.485N.cm^-1The distribution ratio of pore diameter of 100nm or more is measured by mercury intrusion method.

The microstructure of the catalyst and the modified alumina-based carrier is represented by a scanning electron microscope, and the method specifically comprises the following operation: a JSM-7500F scanning electron microscope is adopted to represent the microstructure of the catalyst and the modified alumina-based carrier, the accelerating voltage is 5KV, the accelerating current is 20 muA, and the working distance is 8 mm.