A method for preparing a naphtha hydrofining catalyst
By preparing and sulfiding a naphtha hydrorefining catalyst to form a Co-Mo-S phase, the problem of poor desulfurization and denitrification performance of existing catalysts under low space velocity, high hydrogen pressure, and low hydrogen-oil ratio conditions is solved, and highly efficient hydrodesulfurization performance is achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHINA PETROLEUM & CHEMICAL CORP
- Filing Date
- 2022-12-07
- Publication Date
- 2026-07-03
AI Technical Summary
Existing reforming pre-hydrogenation catalysts are not effective at desulfurization and denitrification under conditions of low space velocity, high hydrogen pressure, and low hydrogen-to-oil ratio. High-performance catalysts need to be developed to meet the requirements of catalytic reforming.
An alumina support is impregnated with a mixed solution of molybdenum trioxide, cobalt sulfate, phosphoric acid, and water. After drying and calcination, a Co-Mo-S active phase is formed. Sulfidation treatment under specific temperature and atmosphere conditions generates more Co-Mo-S phase, thereby improving the hydrodesulfurization effect of the catalyst.
In the process of naphtha hydrorefining, the catalyst exhibits excellent hydrodesulfurization performance, meeting the operating conditions of low space velocity, high hydrogen pressure, and low hydrogen-to-oil ratio, thus achieving efficient desulfurization and denitrification.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of petroleum refining, and specifically relates to a method for preparing a catalyst for the hydrorefining of naphtha. Background Technology
[0002] Catalytic reformed gasoline is characterized by low olefin content, high aromatic content, and sulfur-free properties, making it an ideal clean gasoline component. Pre-hydrogenation treatment effectively removes harmful impurities from naphtha, ensuring it meets the requirements for catalytic reforming (sulfur and nitrogen content <0.5 μg / g, arsenic content <1 ng / g). Currently, due to limitations in the performance of reforming pre-hydrogenation catalysts, reforming pre-hydrogenation is conducted under conditions of low space velocity, high hydrogen pressure, and high hydrogen-to-oil ratio. Therefore, it is essential to develop high-performance reforming pre-hydrogenation catalysts to ensure that reforming pre-hydrogenation can be carried out at high space velocities (6–10 h⁻¹). -1 It achieves good desulfurization and denitrification effects under conditions of low hydrogen pressure (<2.5MPa) and low hydrogen-to-oil ratio (<150m / m).
[0003] The deep hydrodesulfurization of petroleum fractions places increasingly higher demands on the activity of hydrodesulfurization catalysts. Typically, hydrodesulfurization catalysts use Group VIB and Group VIII metals as active components. Group VIB metals are generally Mo and W, while Group VIII metals are generally Co and Ni. Before use, the catalyst needs to be reduced from its oxidized state to its sulfide state to acquire activity. Therefore, the sulfidation step of the catalyst has a significant impact on its performance.
[0004] CN201110321357 discloses a method for sulfiding a hydrorefining catalyst. This method introduces hydrogen sulfide and injects a sulfiding agent into the system at a relatively high temperature, avoiding the low-temperature separate sulfidation of Co and Ni. Thus, under the conditions of higher temperature and the presence of hydrogen sulfide, Mo and W simultaneously sulfidate with Co and Ni to form a highly active Co(Ni)-Mo(W)-S phase. Summary of the Invention
[0005] To address the shortcomings of existing technologies, this invention provides a method for preparing a naphtha hydrorefining catalyst. The catalyst prepared by this method generates more Co-Mo-S phase after sulfidation, exhibiting excellent hydrodesulfurization performance during naphtha hydrorefining.
[0006] The preparation method of the naphtha hydrorefining catalyst of the present invention includes the following steps:
[0007] (1) Molybdenum trioxide, cobalt sulfate, phosphoric acid and water are mixed at a certain temperature to obtain a clear solution;
[0008] (2) Impregnate the alumina support with the clear solution obtained in step (1), dry and calcine to obtain the naphtha hydrorefining catalyst.
[0009] In the method of the present invention, the mass ratio of molybdenum trioxide, cobalt sulfate, phosphoric acid and water in step (1) is: 6.0~18.0: 2.0~5.0: 1.5~2.3; 74.7~90.5.
[0010] In the method of the present invention, the temperature in step (1) is 80~95℃, and the mixture is mixed for a period of time until a clear solution is obtained. The mixing time is generally 60~90 minutes.
[0011] In the method of the present invention, the immersion time in step (2) is 30 to 90 minutes, and the immersion is generally carried out at room temperature.
[0012] In the method of the present invention, the drying conditions in step (2) are: drying temperature of 100℃~150℃ and drying time of 3~5 hours.
[0013] In the method of the present invention, the calcination conditions in step (2) are: calcination temperature of 350℃~450℃, calcination time of 3~5 hours, and the calcination is carried out in an air atmosphere.
[0014] This invention also provides a sulfidation method for naphtha hydrorefining catalyst, comprising the following steps: A reactor is loaded with naphtha hydrorefining catalyst; after ensuring airtightness, sulfiding oil is introduced into the reactor; after the catalyst bed is wetted, sulfidation treatment is performed; after sulfidation, the feedstock oil is switched for normal operation; the sulfidation conditions are: hydrogen partial pressure 3.0~8.0 MPa, hydrogen-to-oil volume ratio 300~800, and space velocity 1.5~3.0 h⁻¹. -1 The temperature is kept constant at 80~120℃ for 3~10 hours, then raised to 180~250℃ and kept constant for 6~10 hours, then raised to 280~340℃ and kept constant for 6~10 hours, and finally raised to 350~450℃ and kept constant for 6~10 hours.
[0015] The aforementioned airtight process is well known in the art and generally involves nitrogen airtightening, hydrogen replacement, and hydrogen airtightening.
[0016] The sulfurized oil is straight-run gasoline, straight-run kerosene, refined gasoline, or refined kerosene. The sulfurizing agent can be one or more commonly used sulfurizing agents in the art, such as carbon disulfide, dimethyl disulfide, and thiophene. Liquid-phase sulfurizing agents or elemental sulfur are added to the sulfurized oil during use.
[0017] The Co-Mo-S phase ratio of the naphtha hydrorefining catalyst after sulfidation by the sulfidation method of the present invention is 90%~100%, and the Co-Mo-S phase ratio is the molar ratio of Co-Mo-S to Mo.
[0018] The method of this invention is characterized by the sulfidation of molybdenum oxide species on the catalyst at a temperature below 340°C to form MoS2, and then the decomposition of cobalt sulfate on the catalyst at a temperature of 350~450°C to generate cobalt oxide species. The cobalt oxide is then sulfidated to generate cobalt sulfide. The newly generated cobalt sulfide is distributed on the molybdenum sulfide grains to form a Co-Mo-S active phase structure. After sulfidation, almost all of the cobalt oxide after the decomposition of cobalt sulfate forms a Co-Mo-S active phase structure. Detailed Implementation
[0019] The present invention will be further described in detail below with reference to the embodiments. In the present invention, the specific surface area and pore volume were determined by low-temperature liquid nitrogen adsorption method. The Co-Mo-S phase ratio was tested by X-ray photoelectron spectroscopy (XPS). The properties of the support and catalyst are shown in Table 1, the properties of the sulfurized oil and feedstock oil are shown in Table 2, the in-situ infrared characterization results of the sulfurized catalyst are shown in Table 3, and the properties of the generated oil are shown in Table 4.
[0020] Example 1
[0021] (1) Add 140 mL of deionized water and 9.7 g of phosphoric acid to a 400 mL Erlenmeyer flask, turn on the magnetic stirrer, and then add 45.3 g of molybdenum trioxide and 44 g of cobalt sulfate heptahydrate. Heat the mixture in the Erlenmeyer flask at 90 °C for 2 hours, then let it cool naturally to 30 °C. Dilute the solution to 200 mL and filter out the insoluble matter for later use.
[0022] (2) Take 85 mL of the solution prepared in step (1), saturate and impregnate 100 g of the carrier, let it grow for 8 hours, dry it at 110℃ for 4 hours, and calcine it at 430℃ for 3 hours to obtain the finished catalyst, numbered A-01.
[0023] (3) Catalyst sulfidation conditions: hydrogen partial pressure 4.0 MPa, hydrogen-to-oil volume ratio 500, space velocity 2.0 h⁻¹ -1 10 mL of catalyst A-01 was loaded, dried, and sealed with nitrogen, replaced with hydrogen, and sealed with hydrogen. The sealing was qualified. Sulfated oil was introduced into the reactor, and the catalyst bed was wetted. The temperature was increased to 110°C at 3°C / min and held for 8 hours. The temperature was increased to 230°C at 1°C / min and held for 8 hours. The temperature was increased to 290°C at 1°C / min and held for 8 hours. The temperature was increased to 360°C at 1°C / min and held for 8 hours.
[0024] After sulfidation, the feedstock was switched to straight-run naphtha. The evaluation conditions were: hydrogen partial pressure 2.0 MPa, hydrogen-to-oil volume ratio 100, and space velocity 6.0 h⁻¹. -1 The reaction temperature was 285℃, and after stabilizing for 24 hours, trace amounts of nitrogen and sulfur were sampled and analyzed. The sample number was B-01.
[0025] Example 2
[0026] Take 95 mL of the solution prepared in step (1) of Example 1, saturate and impregnate 100 g of the carrier, let it grow for 8 hours, dry it at 110℃ for 4 hours, and calcine it at 430℃ for 3 hours to obtain the finished catalyst, numbered A-02.
[0027] (3) Catalyst sulfidation conditions: hydrogen partial pressure 4.0 MPa, hydrogen-to-oil volume ratio 500, space velocity 2.0 h⁻¹ -1 10 mL of catalyst A-02 was loaded, dried, and sealed with nitrogen, replaced with hydrogen, and sealed with hydrogen. The sealing was qualified. Sulfated oil was introduced into the reactor, and the catalyst bed was wetted. The temperature was increased to 110°C at 3°C / min and held for 8 hours. The temperature was increased to 230°C at 1°C / min and held for 8 hours. The temperature was increased to 290°C at 1°C / min and held for 8 hours. The temperature was increased to 380°C at 1°C / min and held for 8 hours.
[0028] After sulfidation, the feedstock was switched to straight-run naphtha. The evaluation conditions were: hydrogen partial pressure 2.0 MPa, hydrogen-to-oil volume ratio 100, and space velocity 6.0 h⁻¹. -1 The reaction temperature was 285℃, and after stabilizing for 24 hours, trace amounts of nitrogen and sulfur were sampled and analyzed. The sample number was B-02.
[0029] Example 3
[0030] Same as Example 1, except for the catalyst sulfidation conditions: hydrogen partial pressure 4.0 MPa, hydrogen-to-oil volume ratio 500, and space velocity 2.0 h⁻¹. -1 10 mL of catalyst A-01 was loaded, dried, and sealed with nitrogen, replaced with hydrogen, and sealed with hydrogen. The sealing was qualified. Sulfated oil was introduced into the reactor to wet the catalyst bed. After sulfidation, the temperature was increased to 110°C at 3°C / min and held for 8 hours. Then, the temperature was increased to 230°C at 1°C / min and held for 8 hours. Finally, the temperature was increased to 290°C at 1°C / min and held for 8 hours. Then, the temperature was increased to 420°C at 1°C / min and held for 8 hours.
[0031] After sulfidation, the feedstock was switched to straight-run naphtha. The evaluation conditions were: hydrogen partial pressure 2.0 MPa, hydrogen-to-oil volume ratio 100, and space velocity 6.0 h⁻¹. -1 The reaction temperature was 285℃, and after stabilizing for 24 hours, trace amounts of nitrogen and sulfur were sampled and analyzed. The sample number was B-03.
[0032] Comparative Example 1
[0033] Same as Example 1, except for the catalyst sulfidation conditions: hydrogen partial pressure 4.0 MPa, hydrogen-to-oil volume ratio 500, and space velocity 2.0 h⁻¹. -110 mL of catalyst A-01 was loaded, and the catalyst was dried, sealed with nitrogen, replaced with hydrogen, and sealed with hydrogen. The sealing was qualified. Sulfated oil was introduced into the reactor to wet the catalyst bed. After sulfidation, the temperature was increased to 110°C at 3°C / min and held for 8 hours. Then the temperature was increased to 230°C at 1°C / min and held for 8 hours. Finally, the temperature was increased to 320°C at 1°C / min and held for 8 hours.
[0034] After sulfidation, the feedstock was switched to straight-run naphtha. The evaluation conditions were: hydrogen partial pressure 2.0 MPa, hydrogen-to-oil volume ratio 100, and space velocity 6.0 h⁻¹. -1 The reaction temperature was 285℃, and after stabilizing for 24 hours, trace amounts of nitrogen and sulfur were sampled and analyzed. The sample number was B-04.
[0035] Comparative Example 2
[0036] Same as Example 2, except for the catalyst sulfidation conditions: hydrogen partial pressure 4.0 MPa, hydrogen-to-oil volume ratio 500, and space velocity 2.0 h⁻¹. -1 10 mL of catalyst A-02 was loaded, and the catalyst was dried, sealed with nitrogen, replaced with hydrogen, and sealed with hydrogen. The sealing was qualified. Sulfated oil was introduced into the reactor to wet the catalyst bed. After sulfidation, the temperature was increased to 110°C at 3°C / min and held for 8 hours. Then the temperature was increased to 230°C at 1°C / min and held for 8 hours. Finally, the temperature was increased to 320°C at 1°C / min and held for 8 hours.
[0037] After sulfidation, the feedstock was switched to straight-run naphtha. The evaluation conditions were: hydrogen partial pressure 2.0 MPa, hydrogen-to-oil volume ratio 100, and space velocity 6.0 h⁻¹. -1 The reaction temperature was 285℃, and after stabilizing for 24 hours, trace amounts of nitrogen and sulfur were sampled and analyzed. The sample number was B-05.
[0038] Comparative Example 3
[0039] (1) Preparation of impregnation solution
[0040] Add 140 mL of deionized water and 9.7 g of phosphoric acid to a 400 mL Erlenmeyer flask. Turn on the magnetic stirrer, then add 45 g of molybdenum trioxide and 23.9 g of basic cobalt carbonate. Heat the mixture in the Erlenmeyer flask at 90 °C for 2 hours, then allow it to cool naturally to 30 °C. Dilute the solution to 200 mL and filter out the insoluble matter for later use.
[0041] (2) Take 85 mL of the impregnation solution from step (1), 100 g of saturated impregnation carrier, and after curing for 8 hours, dry at 110℃ for 4 hours and calcine at 430℃ for 3 hours to obtain the finished catalyst, numbered A-03.
[0042] (3) Catalyst sulfidation conditions: hydrogen partial pressure 4.0 MPa, hydrogen-to-oil volume ratio 500, space velocity 2.0 h⁻¹ -110 mL of catalyst A-03 was loaded, and the catalyst was dried, sealed with nitrogen, replaced with hydrogen, and sealed with hydrogen. The sealing was qualified. Sulfated oil was introduced into the reactor, and the catalyst bed was wetted. The temperature was increased to 110°C at 3°C / min and held for 8 hours. The temperature was increased to 230°C at 1°C / min and held for 8 hours. The temperature was increased to 320°C at 1°C / min and held for 8 hours.
[0043] After sulfidation, the feedstock was switched to straight-run naphtha. The evaluation conditions were: hydrogen partial pressure 2.0 MPa, hydrogen-to-oil volume ratio 100, and space velocity 6.0 h⁻¹. -1 The reaction temperature was 285℃, and after stabilizing for 24 hours, trace amounts of nitrogen and sulfur were sampled and analyzed. The sample number was B-06.
[0044] Comparative Example 4
[0045] Same as Comparative Example 3, except the vulcanization conditions are:
[0046] Catalyst sulfidation conditions: hydrogen partial pressure 4.0 MPa, hydrogen-to-oil volume ratio 500, space velocity 2.0 h⁻¹ -1 10 mL of catalyst A-03 was loaded, dried, and tested for nitrogen tightness, hydrogen purging, and hydrogen tightness; the tightness was deemed satisfactory. Sulfated oil was introduced into the reactor, and the catalyst bed was wetted. The temperature was then increased at 3°C / min to 110°C and held for 8 hours. Next, the temperature was increased at 1°C / min to 230°C and held for 8 hours. Finally, the temperature was increased at 1°C / min to 290°C and held for 8 hours. Then, the temperature was increased at 1°C / min to 360°C and held for 8 hours. After sulfidation, the feedstock was switched to straight-run naphtha. The evaluation conditions were: hydrogen partial pressure 2.0 MPa, hydrogen-to-oil volume ratio 100, and space velocity 6.0 h⁻¹. -1 The reaction temperature was 285℃, and after stabilizing for 24 hours, trace amounts of nitrogen and sulfur were sampled and analyzed. The sample number was B-07.
[0047] Table 1 Physicochemical properties of the support and catalyst
[0048]
[0049] Table 2 Properties of Sulfated Oil and Feedstock
[0050]
[0051] Table 3. In-situ infrared characterization results of the sulfidated catalyst at different temperatures.
[0052]
[0053] Table 4 Properties of the generated oil
[0054]
Claims
1. A method for sulfiding a naphtha hydrofining catalyst, characterized by: The process includes the following: The reactor is filled with naphtha hydrorefining catalyst. After the airtightness is qualified, sulfurized oil is introduced into the reactor. After the catalyst bed is wetted, sulfurization treatment is carried out. After the sulfurization is completed, the feedstock oil is switched to carry out normal operation. The sulfidation treatment conditions are: hydrogen partial pressure 3.0~8.0 MPa, hydrogen-to-oil volume ratio 300~800, and space velocity 1.5~3.0 h⁻¹. -1 The temperature is kept constant at 80~120℃ for 3~10 hours, then raised to 180~250℃ and kept constant for 6~10 hours, then raised to 280~340℃ and kept constant for 6~10 hours, then raised to 350~450℃ and kept constant for 6~10 hours. The preparation method of the naphtha hydrorefining catalyst includes: (1) mixing molybdenum trioxide, cobalt sulfate, phosphoric acid and water at a certain temperature to obtain a clear solution; (2) impregnating an alumina support with the clear solution obtained in step (1), drying and calcining to obtain the naphtha hydrorefining catalyst. The mass ratio of molybdenum trioxide, cobalt sulfate, phosphoric acid, and water in step (1) is 6.0~18.0: 2.0~5.0: 1.5~2.3: 74.7~90.5; The Co-Mo-S phase ratio of the sulfided naphtha hydrorefining catalyst is 90%~100%, and the Co-Mo-S phase ratio is the molar ratio of Co-Mo-S to Mo.
2. The vulcanization method according to claim 1, characterized in that: The temperature mentioned in step (1) is 80~95℃.
3. The vulcanization method according to claim 1, characterized in that: The soaking time in step (2) is 30 to 90 minutes.
4. The vulcanization method of claim 1, wherein: The drying conditions described in step (2) are: drying temperature of 100~150℃ and drying time of 3~5 hours.
5. The vulcanization method of claim 1, wherein: The roasting conditions described in step (2) are: roasting temperature of 350~450℃ and roasting time of 3~5 hours.
6. The vulcanization method of claim 1, wherein: The sulfurized oil is one or more of straight-run gasoline, straight-run kerosene, refined gasoline, or refined kerosene; the sulfurizing agent is one or more of carbon disulfide, dimethyl disulfide, or thiophene.