A sulfur-resistant catalyst for saturated hydrogenation of aromatics, preparation method thereof, and application thereof

Abstract

The invention discloses a kind of aromatic hydrocarbon saturation hydrogenation anti-sulfur catalyst and its preparation method and application, belong to oil catalytic hydrogenation field.The present invention utilizes the topological transformation property of hydrotalcite to introduce metal Mo, obtains the precursor of active component uniform dispersion, utilizes NaBH4 low temperature reduction this precursor, directly obtains highly dispersed NiMo / Al-LDH catalyst.The catalyst shows excellent catalytic performance and anti-sulfur performance in vacuum residue and naphthalene catalytic hydrogenation reaction, naphthalene can be completely converted under mild conditions, and the selectivity of decahydronaphthalene reaches 100%, in addition, cycloalkane content can reach 16.9% in the n-hexane solubles obtained from catalytic hydrogenation residue, is significantly higher than non-catalytic.The present invention does not need to use hydrogen, is safe and environmentally friendly, and simultaneously catalyst preparation method is simple, active, stable and has anti-sulfur performance, therefore has good application prospect in the catalytic hydrogenation of vacuum residue, various heavy oils and coal.

Description

Technical Field

[0001] The invention belongs to the field of catalytic hydrogenation of oil products, and particularly relates to a sulfur-resistant catalyst for saturated hydrogenation of aromatics and its preparation, as well as application of the catalyst to catalytic hydrogenation of vacuum residue. Background Art

[0002] Vacuum residue concentrates a large amount of impurities such as S, N and heavy metals in crude oil, which can easily cause catalyst poisoning and deactivation during the reaction process, posing a challenge to the preparation of residue hydro-upgrading catalysts.

[0003] Transition metals such as molybdenum (Mo), nickel (Ni), cobalt (Co), and tungsten (W) are generally preferred active components for the catalytic hydrogenation of residue oils. Generally speaking, residue oil upgrading catalysts are divided into two categories: supported catalysts and unsupported catalysts. Supported catalysts are the most commonly used catalyst type and are typically used in fixed-bed and bubbling-bed reactors. Rana et al. studied the effects of CoMo / Al2O3 catalysts on the conversion of asphaltene, sulfur, and metallic impurities during the hydroprocessing of Maya crude oil and found that when the CoMo / Al2O3 catalyst had a larger average pore size, the conversion of metallic impurities and aromatics in Maya crude oil was higher, while the conversion of sulfur was more dependent on the dispersion of the active metal on the CoMo / Al2O3 catalyst. Catalysts with smaller pore sizes (approximately 6.5 nm) had the lowest activity for the hydrodemetallization and catalytic hydrogenation of aromatics saturation of Maya crude oil, but the highest activity for hydrodesulfurization (Catalyst Today, 2019, 353:204-212). Santes et al. found that NiMo / γ-Al2O3-TiO2 exhibits high catalytic activity for heavy gasoline. When the Ni / (Ni+Mo) ratio is 0.45, the catalyst exhibits high catalytic hydrodemetallization performance even at a relatively low temperature of 330°C (Petroleum Science and Technology, 2014, 22(1-2):103-117). We have also conducted related research and found that NiMoS / γ-Al2O3 can effectively reduce the content of sulfur compounds in kerosene co-refined oil while promoting the formation of cycloalkanes. After continuous hydrogenation at 280°C for 10 hours, the sulfur content of the kerosene co-refined oil was reduced to 9.1 mg / L, while the cycloalkanes content increased to 29.9% (Fuel, 2022, 323:01-07).

[0004] It can be seen that based on the high activity and excellent sulfur resistance of NiMo bimetallic supported catalysts, this paper used hydrotalcite as a precursor and utilized the topological transformation property of hydrotalcite to prepare highly dispersed NiMo bimetallic supported catalysts, which is of great significance for the preparation of residue hydroprocessing catalysts. Summary of the Invention

[0005] In view of the shortcomings of the existing technology, the technical problem to be solved in this paper is to provide a highly active hydrogenation sulfur-resistant NiMo / Al-LDH catalyst and its application in the catalytic hydrogenation of vacuum residue to achieve the quality improvement of the residue.

[0006] In order to solve the above technical problems, the present invention is implemented through the following technical solutions.

[0007] The catalyst of the present invention uses NiMo alloy as the active component of the catalyst and NiAl hydrotalcite (NiAl-LDH) as the carrier. The average particle sizes of the active components Ni and Mo are 0.60 and 0.92 nm respectively. There is a strong electronic interaction between Ni and Mo, and the specific surface area is 69.2 m 2 / g, and the average pore diameter is 35.4nm.

[0008] The present invention provides a method for preparing the above catalyst, which specifically comprises the following steps:

[0009] (1) 0.04-0.07 mol urea, 0.1-0.2 mol Ni(NO3)2·6H2O, and 0.1-0.3 mol Al(NO3)3·9H2O were mixed uniformly in 10 mL deionized water, stirred at 90-140°C for 6-12 h, centrifuged, filtered, washed, and then vacuum-dried to obtain NiAl-LDH;

[0010] (2) Take 0.4-0.8g (NH4)6Mo7O 24 4H2O was prepared into solution A in 100mL of deionized water; 200mg of NiAl-LDH obtained in step (1) was added into 10mL of deionized water and 1mL of solution A, and stirred to obtain NiMoAl-LDH solution;

[0011] (3) directly reducing the NiMoAl-LDH solution obtained in step (2) with NaBH4; centrifuging, filtering, washing, and vacuum drying to obtain the target product: Ni-Mo / Al-LDH catalyst.

[0012] In the step (3), the NaBH4 reduction temperature is 120-180° C., and the reduction time is 2-6 h.

[0013] The present invention also provides the use of the catalyst prepared by the above method in the catalytic hydrogenation of vacuum residue oil and its model compound, which specifically comprises the following steps:

[0014] NiMo / Al-LDH catalyst, substrate, and n-dodecane are added to a reactor in a ratio of 10-50 mg:100-400 mg:20-30 mL. After sealing, the reactor is flushed with 2.5 MPa of H₂ and reacted at 260-320°C for 0.5-6 hours to obtain a catalytic hydrogenation product. The substrate is selected from naphthalene, a mixture of naphthalene and 1 wt% thiophene, or vacuum residue.

[0015] Compared with the prior art, the present invention has the following technical effects:

[0016] 1. The present invention utilizes the topological transition properties of hydrotalcite to introduce metallic Mo to obtain a NiMoAl-LDH precursor with uniformly dispersed active components. The precursor is reduced at low temperature using NaBH4 to directly obtain a highly dispersed NiMo / Al-LDH catalyst.

[0017] 2. The catalyst prepared by the present invention has high dispersion and the active components are evenly dispersed ( Figure 2 ), the catalytic hydrogenation of aromatic saturation is highly active and can quickly and completely convert naphthalene. In addition, the cycloparaffin content in the n-hexane solubles obtained from catalytic hydrogenation of residual oil can reach 16.9%, significantly higher than that of non-catalytic hydrogenation.

[0018] 3. The catalyst prepared by the present invention has a certain sulfur resistance. When 1 wt% of thiophene is added to the reactants, it can still maintain a high aromatic hydrocarbon saturation activity.

[0019] 4. The catalyst prepared by the present invention has good stability and can still maintain high activity after being recycled five times.

[0020] 5. The catalyst preparation method of the present invention is simple, and no hydrogen is required in the reduction process. It is safe and environmentally friendly, and has good application prospects in the catalytic hydrogenation of vacuum residue oil, various heavy oils and coal.

[0021] 6. Vacuum residue is the residual oil produced by crude oil refining. The present invention realizes the lightweighting of vacuum residue, which is of great significance to the efficient utilization of residual oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is the XRD pattern of the Ni-Mo / Al-LDH catalyst in Example 1 of the present invention;

[0023] As can be seen from the figure, the support of the Ni-Mo / Al-LDH catalyst mainly exists in the form of NiAl hydrotalcite, and the active components Ni and Mo are highly dispersed.

[0024] Figure 2 The SEM image (a) and TEM images (bd) at different magnifications of the Ni-Mo / Al-LDH catalyst in Example 1 of the present invention are shown;

[0025] pass Figure 2 (a) It can be seen that the Ni-Mo / Al-LDH catalyst is composed of uniform hexagonal nanosheets. Figure 2 (bc) It can be seen that the active components in the Ni-Mo / Al-LDH catalyst are uniformly dispersed. The average particle sizes of the active components Ni and Mo are 0.60 nm ( Figure 2 b) and 0.92nm( Figure 2 c), which also indicates that the active ingredient has a high dispersion. Figure 2 Lattice fringes of Ni(111) and MoO3(111) can be seen in (d), which is consistent with the results of XRD analysis. DETAILED DESCRIPTION

[0026] The present invention is described in detail below with reference to the following embodiments, but the present invention is not limited to the following embodiments.

[0027] Example 1

[0028] 0.07 mol urea, 0.3 mol Al(NO3)3·9H2O and 0.2 mol Ni(NO3)2·6H2O were mixed in 10 mL of deionized water and stirred at 140°C for 9 h. NiAl-LDH precursor was obtained after centrifugation, filtration and drying. 24 ·4H2O was prepared into ammonium molybdate solution in 100mL deionized water. 200mg NiAl-LDH precursor and 1mL ammonium molybdate solution were mixed in 15mL deionized water, and 0.2mmol / mL NaBH4 solution was added dropwise. The reaction was stirred at 180℃ for 2h. After the reaction was completed, the precipitate was washed three times with deionized water and placed in a freeze drying oven to dry for 48h to obtain NiMo / Al-LDH catalyst. XRD( Figure 1 ) and SEM, TEM( Figure 2 Characterization revealed that the Ni-Mo / Al-LDH catalyst's support primarily exists in the form of NiAl hydrotalcite, and the active components Ni and Mo are highly dispersed, with average particle sizes of 0.60 and 0.92 nm, respectively. The NiMo / Al-LDH catalyst, naphthalene, and n-dodecane were added to a sealed reactor at a ratio of 20 mg:200 mg:30 mL. The reactor was then filled with 2.5 MPa of hydrogen and reacted at 280°C for 1 hour to obtain a hydrogenated product. The naphthalene conversion rate was 100%, and the selectivity for decalin reached 98.7%. After the catalyst was recycled five times, the naphthalene conversion rate remained at 99.0%.

[0029] Example 2

[0030] 0.06 mol urea, 0.1 mol Al(NO3)3·9H2O and 0.2 mol Ni(NO3)2·6H2O were mixed evenly in 10 mL deionized water and stirred at 90°C for 12 h. NiAl-LDH precursor was obtained after centrifugation, filtration and drying. 24 4H2O was dissolved in 100mL of deionized water to form an ammonium molybdate solution. 200mg of the NiAl-LDH precursor and 1mL of the ammonium molybdate solution were mixed in 15mL of deionized water, and 0.2mmol / mL of NaBH4 solution was added dropwise. The reaction was stirred at 120°C for 6h. After completion of the reaction, the precipitate was washed three times with deionized water and dried in a freeze-dryer for 48h to obtain the NiMo / Al-LDH catalyst. The NiMo / Al-LDH catalyst, naphthalene, thiophene, and n-dodecane were added to the reactor in a ratio of 30mg:200mg:2mg:30mL. The reactor was sealed and filled with 2.5MPa of hydrogen. The reaction was continued at 280°C for 1h to obtain the hydrogenated product. The naphthalene conversion rate was 93.4%, which was only 4.8% lower than when thiophene was not added, indicating that the NiMo / Al-LDH has certain sulfur resistance.

[0031] Example 3

[0032] 0.07 mol urea, 0.1 mol Al(NO3)3·9H2O and 0.2 mol Ni(NO3)2·6H2O were mixed in 10 mL of deionized water and stirred at 140°C for 9 h. NiAl-LDH precursor was obtained after centrifugation, filtration and drying. 24 4H2O was dissolved in 100mL of deionized water to form an ammonium molybdate solution. 200mg of the NiAl-LDH precursor and 1mL of the ammonium molybdate solution were mixed in 15mL of deionized water, and 0.2mmol / mL of NaBH4 solution was added dropwise. The reaction was stirred at 180°C for 2h. After completion of the reaction, the precipitate was washed three times with deionized water and dried in a freeze-drying oven for 48h to obtain the NiMo / Al-LDH catalyst. The NiMo / Al-LDH catalyst, naphthalene, and n-dodecane were added to a reactor in a ratio of 20mg:200mg:30mL. The reactor was sealed and filled with 2.5MPa of hydrogen. The reaction was continued at 260°C for 1h to obtain the hydrogenation product. The naphthalene conversion was 85.6%, with decahydronaphthalene being the main product, and the selectivity reached 90.5%.

[0033] Example 4

[0034] 0.07 mol urea, 0.1 mol Al(NO3)3·9H2O and 0.1 mol Ni(NO3)2·6H2O were mixed in 10 mL of deionized water and stirred at 120°C for 6 h. NiAl-LDH precursor was obtained after centrifugation, filtration and drying. 24 4H2O was dissolved in 100mL of deionized water to form an ammonium molybdate solution. 200mg of the NiAl-LDH precursor and 1mL of the ammonium molybdate solution were mixed in 15mL of deionized water, and 0.2mmol / mL of NaBH4 solution was added dropwise. The reaction was stirred at 150°C for 4h. After completion of the reaction, the precipitate was washed three times with deionized water and dried in a freeze-drying oven for 48h to obtain the NiMo / Al-LDH catalyst. The NiMo / Al-LDH catalyst, naphthalene, and n-dodecane were added to a reactor in a ratio of 20mg:200mg:30mL. The reactor was sealed and filled with hydrogen at 2.5MPa. The reaction was continued at 240°C for 1h to obtain the hydrogenation product. The naphthalene conversion was 59.2%, with decahydronaphthalene being the main product, and the selectivity reached 89.8%.

[0035] Example 5

[0036] 0.04 mol urea, 0.1 mol Al(NO3)3·9H2O and 0.2 mol Ni(NO3)2·6H2O were mixed in 10 mL of deionized water and stirred at 140°C for 9 h. NiAl-LDH precursor was obtained after centrifugation, filtration and drying. 24 4H2O was dissolved in 100mL of deionized water to form an ammonium molybdate solution. 200mg of the NiAl-LDH precursor and 1mL of the ammonium molybdate solution were mixed in 15mL of deionized water, and 0.2mmol / mL of NaBH4 solution was added dropwise. The reaction was stirred at 180°C for 2h. After completion of the reaction, the precipitate was washed three times with deionized water and dried in a freeze-drying oven for 48h to obtain the NiMo / Al-LDH catalyst. The NiMo / Al-LDH catalyst, naphthalene, and n-dodecane were added to a reactor in a ratio of 10mg:200mg:30mL. The reactor was sealed and filled with hydrogen at 2.5MPa. The reaction was continued at 280°C for 1.5h to obtain the hydrogenation product. The naphthalene conversion was 96.7%, with decahydronaphthalene being the main product, and the selectivity reached 100%.

[0037] Example 6

[0038] 0.04 mol urea, 0.1 mol Al(NO3)3·9H2O and 0.1 mol Ni(NO3)2·6H2O were mixed in 10 mL of deionized water and stirred at 140°C for 9 h. NiAl-LDH precursor was obtained after centrifugation, filtration and drying. 24 4H2O was dissolved in 100mL of deionized water to form an ammonium molybdate solution. 200mg of NiAl-LDH precursor and 1mL of ammonium molybdate solution were mixed in 15mL of deionized water, and 0.2mmol / mL of NaBH4 solution was added dropwise. The reaction was stirred at 180°C for 2h. After completion of the reaction, the precipitate was washed three times with deionized water and dried in a freeze-drying oven for 48h to obtain the NiMo / Al-LDH catalyst. The NiMo / Al-LDH catalyst, naphthalene, and n-dodecane were added to a reactor in a ratio of 50mg:200mg:30mL. The reactor was sealed and filled with 2.5MPa of hydrogen. The reaction was continued at 280°C for 0.5h to obtain the hydrogenation product. The naphthalene conversion was 100%, with decahydronaphthalene being the main product, and the selectivity reached 96.3%.

[0039] Example 7

[0040] 0.04 mol urea, 0.1 mol Al(NO3)3·9H2O and 0.1 mol Ni(NO3)2·6H2O were mixed in 10 mL of deionized water and stirred at 140°C for 9 h. NiAl-LDH precursor was obtained after centrifugation, filtration and drying. 24 4H2O was dissolved in 100mL of deionized water to form an ammonium molybdate solution. 200mg of NiAl-LDH precursor and 1mL of ammonium molybdate solution were mixed in 15mL of deionized water, and 0.2mmol / mL of NaBH4 solution was added dropwise. The reaction was stirred at 180°C for 2h. After completion of the reaction, the precipitate was washed three times with deionized water and dried in a freeze-drying oven for 48h to obtain the NiMo / Al-LDH catalyst. The NiMo / Al-LDH catalyst, vacuum residue oil, and n-dodecane were added to a reactor in a ratio of 20mg:400mg:30mL. The reactor was sealed and filled with hydrogen at 2.5MPa. The reaction was continued at 300°C for 6h to obtain the hydrogenated product. The conversion of the vacuum residue oil was 95.1%, and the cycloalkane content in the n-hexane-soluble product reached 16.5%.

[0041] Example 8

[0042] 0.04 mol urea, 0.1 mol Al(NO3)3·9H2O and 0.1 mol Ni(NO3)2·6H2O were mixed in 10 mL of deionized water and stirred at 140°C for 9 h. NiAl-LDH precursor was obtained after centrifugation, filtration and drying. 24 4H2O was dissolved in 100mL of deionized water to form an ammonium molybdate solution. 200mg of NiAl-LDH precursor and 1mL of ammonium molybdate solution were mixed in 15mL of deionized water, and 0.2mmol / mL of NaBH4 solution was added dropwise. The reaction was stirred at 180°C for 2h. After completion of the reaction, the precipitate was washed three times with deionized water and dried in a freeze-drying oven for 48h to obtain the NiMo / Al-LDH catalyst. The NiMo / Al-LDH catalyst, vacuum residue oil, and n-dodecane were added to a reactor in a ratio of 20mg:100mg:30mL. The reactor was sealed and filled with hydrogen at 2.5MPa. The reaction was continued at 320°C for 6h to obtain the hydrogenated product. The conversion of the vacuum residue oil was 98.1%, and the cycloalkane content in the n-hexane-soluble fraction of the product reached 15.8%.

[0043] Example 9

[0044] 0.04 mol urea, 0.1 mol Al(NO3)3·9H2O and 0.1 mol Ni(NO3)2·6H2O were mixed in 10 mL of deionized water and stirred at 140°C for 9 h. NiAl-LDH precursor was obtained after centrifugation, filtration and drying. 24 4H2O was dissolved in 100mL of deionized water to form an ammonium molybdate solution. 200mg of NiAl-LDH precursor and 1mL of ammonium molybdate solution were mixed in 15mL of deionized water, and 0.2mmol / mL of NaBH4 solution was added dropwise. The reaction was stirred at 180°C for 2h. After completion of the reaction, the precipitate was washed three times with deionized water and dried in a freeze-drying oven for 48h to obtain the NiMo / Al-LDH catalyst. The NiMo / Al-LDH catalyst, vacuum residue oil, and n-dodecane were added to a reactor in a ratio of 20mg:200mg:20mL. The reactor was sealed and filled with 2.5MPa of hydrogen. The reaction was continued at 340°C for 6h to obtain the hydrogenated product. The conversion of the vacuum residue oil was 93.4%, and the cycloalkane content in the n-hexane-soluble fraction of the product reached 10.5%.

Claims

1. Application of an aromatic hydrocarbon saturation hydrogenation sulfur-resistant catalyst in the catalytic hydrogenation of vacuum residue or its model compound, characterized in that: The preparation of the catalyst comprises the following steps: (1) Take 0.04-0.07 mol urea, 0.1-0.2 mol Ni(NO3)2·6H2O and 0.1-0.3 mol Al(NO3)3·9H2O and mix them evenly in 10 mL deionized water. o C, stirred for 6-12 h, centrifuged, filtered, washed, and then vacuum-dried to obtain NiAl-LDH; (2) Take 0.4-0.8 g (NH4)6Mo7O 24 4H2O was prepared into solution A in 100 mL of deionized water; 200 mg of NiAl-LDH obtained in step (1) was added into 10 mL of deionized water and 1 mL of solution A, and stirred to obtain NiMoAl-LDH solution; (3) directly reducing the NiMoAl-LDH solution obtained in step (2) with NaBH4; centrifuging, filtering, washing, and vacuum drying to obtain the target product: Ni-Mo / Al-LDH catalyst; The NaBH4 reduction temperature in step (3) is 120-180 o C, reduction time is 2-6 h.

2. Use of the sulfur-resistant catalyst for saturated hydrogenation of aromatics according to claim 1 in the catalytic hydrogenation of vacuum residue or its model compound, characterized in that The steps include: NiMo / Al-LDH catalyst, substrate and n-dodecane were added into the reactor in the ratio of 10-50 mg: 100-400 mg: 20-30 mL, sealed and filled with 2.5 MPa of hydrogen. o C for 0.5-6 h to obtain the product; The substrate is one of naphthalene, a mixture of naphthalene and 1 wt% thiophene, or vacuum residue.

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