A grading method for hydroprocessing catalyst

Abstract

The present invention discloses a grading method for a hydroprocessing catalyst, wherein the grading method loads M hydroprocessing catalysts along the flow direction of the logistics, wherein M is at least 2, preferably M is at least 3, and further preferably M is 3-7, and M can specifically be 2, 3, 4 or 5, and preferably M is 3, wherein the molar concentration of nickel atoms on the surface of the M-th hydroprocessing catalyst is higher than the molar concentration of nickel atoms on the surface of the M-th hydroprocessing catalyst, and the average reaction temperature of the M-th hydroprocessing catalyst bed is higher than the average reaction temperature of the 1st hydroprocessing catalyst bed. The method can not only improve the overall denitrification performance of the hydroprocessing reactor, but also improve the aromatic saturation performance of the catalyst system.

Description

Technical Field

[0001] The invention relates to a grading method for a hydroprocessing catalyst, in particular to a grading method for a hydroprocessing catalyst with deep denitrification and high hydrogenation saturation performance. Background Art

[0002] In modern oil refining technology, hydrocracking refers to those hydrogenation processes that convert more than 10% of the macromolecular compounds in the raw materials into small molecular compounds through hydrogenation reactions. It has the characteristics of strong raw material adaptability, great flexibility in production plans, and good product quality. It can directly convert various heavy and inferior feeds into high-quality jet fuels, diesel, lubricant base materials and chemical naphtha and tail oil steam cracking raw materials for ethylene production that are urgently needed in the market. It has become one of the most important heavy oil deep processing technologies in modern oil refining and petrochemical industries, and has been increasingly widely used at home and abroad.

[0003] The core of hydrocracking technology is the catalyst, including pretreatment catalyst and cracking catalyst. The main function of the hydrocracking pretreatment catalyst is to remove impurities such as sulfur, nitrogen, oxygen and heavy metals contained in the raw materials by hydrogenation, and to hydrogenate saturated polycyclic aromatic hydrocarbons to improve the properties of the oil. Because the nitrides in the raw oil, especially the alkaline nitrides, can poison the acid center of the cracking catalyst, the hydrodenitrogenation performance is an important indicator for measuring the hydrocracking pretreatment catalyst.

[0004] The industrial device is an adiabatic reactor. As the reaction proceeds, the reaction temperature increases significantly, the hydrogen partial pressure decreases, the hydrogen sulfide and ammonia partial pressures increase, the nitrogen content in the reactants decreases, and the remaining nitrogen-containing compounds are molecules that are difficult to denitrify, generally with a multi-side chain structure. The reaction conditions of the upper and lower beds of the catalyst are very different. In order to adapt to the difference in this reaction environment, a catalyst grading system can be developed to maximize the performance of the catalyst and extend its service life.

[0005] CN 112725014 A discloses a grading method for a hydroprocessing catalyst, wherein N catalyst beds are loaded, N is an integer greater than 2, wherein the catalyst loaded in the mth catalyst bed has the highest acid content at 250°C to 500°C, m is an integer greater than 1 and less than N, wherein the acid content at 250°C to 500°C of the catalyst loaded in the 1st to mth catalyst beds increases, the acid content at 250°C to 500°C of the catalyst loaded in the mth to Nth catalyst beds decreases, and the reaction temperature of the catalyst beds increases along the flow. The method can not only improve the overall denitrification and desulfurization performance of the hydroprocessing reactor, but also improve the stability of the catalyst system performance.

[0006] CN 109718867 A relates to the field of hydrorefining catalysts, and discloses a hydrorefining catalyst system and its application, a preparation method of the hydrorefining catalyst, and a method for hydrorefining distillate oil. The catalyst system includes a first and a second catalyst bed; the first catalyst contains alumina, a hydrodesulfurization catalytic active component and a carboxylic acid; the second catalyst contains an inorganic refractory component, a hydrodesulfurization catalytic active component and a carboxylic acid; the second inorganic refractory component contains amorphous silicon aluminum and / or molecular sieve and alumina; the first and second catalysts both have a pore size of 4-40nm and a pore size of 100-300nm, and the pore volume of the pore size of 4-40nm accounts for 60-95% of the total pore volume, and the pore volume of the pore size of 100-300nm accounts for 0.5-30% of the total pore volume. The first and second catalysts have a pore size of 100-300nm, good performance, shortened preparation process, and the ability of the catalyst system to process distillate oil is improved.

[0007] CN 106669861 A discloses a hydrocracking catalyst grading method and a catalytic diesel hydroconversion process. The hydrocracking catalyst grading method of the present invention comprises the following contents: a hydrocracking reactor is equally divided into 2 to 8 reaction zones along the material flow direction, a hydrocracking catalyst and a regenerated catalyst are mixed and loaded in each reaction zone, the mass ratio of the hydrocracking catalyst to the regenerated catalyst in each reaction zone is 10:1 to 1:10, and the mass ratio of the hydrocracking catalyst to the regenerated catalyst in each reaction zone gradually decreases along the material flow direction. The present invention also provides a catalytic diesel hydroconversion process using the above catalyst grading. The present invention improves the hydrogenation selectivity of the diesel / gasoline component in the conversion process and improves the yield of the high-octane gasoline product by grading and loading catalysts with different reaction properties in the cracking reactor.

[0008] The existing technologies mostly focus on the study of catalyst activity and catalyst particle size grading, without considering the influence of catalyst surface properties. In particular, the surface properties of the catalyst have an important influence on the denitrification reaction. Summary of the invention

[0009] In view of the problems existing in the prior art, the present invention provides a grading method for a hydroprocessing catalyst, which is applicable to the hydroprocessing process of various distillate oils. The method can not only improve the overall denitrification performance of the hydroprocessing reactor, but also improve the aromatic saturation performance of the catalyst system.

[0010] A grading method for hydroprocessing catalysts, wherein M types of hydroprocessing catalysts are loaded along a flow direction of a logistics stream, wherein M is at least 2, preferably M is at least 3, and further preferably M is 3-7. Specifically, M can be 2, 3, 4 or 5, and preferably M is 3. The molar concentration of nickel atoms on the surface of the Mth hydroprocessing catalyst is higher than the molar concentration of nickel atoms on the surface of the M-1st hydroprocessing catalyst, and the average reaction temperature of the Mth hydroprocessing catalyst bed is higher than the average reaction temperature of the 1st hydroprocessing catalyst bed.

[0011] Furthermore, in the above method, the molar concentration of nickel atoms on the surface of the Mth hydroprocessing catalyst is 3%-80% higher than the molar concentration of nickel atoms on the surface of the M-1st hydroprocessing catalyst, and preferably 5%-30% higher. The average reaction temperature of the Mth hydroprocessing catalyst is 10°C-60°C higher than the average reaction temperature of the 1st hydroprocessing catalyst, and further preferably 20°C-50°C higher.

[0012] Furthermore, when M in the above method is 3, the average reaction temperature of the M-1st hydroprocessing catalyst bed is higher than or equal to the average reaction temperature of the M-2nd hydroprocessing catalyst bed.

[0013] The average reaction temperature of the layer is preferably higher than 10°C-40°C.

[0014] Furthermore, in the above method, the packing volume ratio of adjacent catalyst beds is 1:20 to 20:1, preferably 1:10 to 10:1, and more preferably 1:5 to 5:1.

[0015] Furthermore, the method described in the above method can process a variety of distillate oil raw materials, including various diesel, VGO, CGO, DAO and mixed oils of two or more thereof, and its main properties are as follows: distillation range, initial distillation point greater than 180°C, final distillation point less than 600°C; density, 0.8000~0.9500 / g·cm -3 (20℃); Nitrogen content, 100~6000μg·g -1 ; Sulfur content, 0.05%~3.0%.

[0016] Furthermore, the hydroprocessing catalyst described in the above method contains group VIB and group VIII metal components. The active metal of group VIB is W and / or Mo, and the active metal of group VIII is Ni and / or Co. The active metals in the final hydroprocessing catalyst are generally 9% to 50% of group VIB metal oxides and 1% to 15% of group VIII metal oxides by weight of oxides. The catalyst carrier is a porous refractory oxide, such as alumina, silica, silica-alumina, alumina in which silica-alumina is dispersed, alumina coated with silica, magnesium oxide, zirconium oxide, boron oxide, titanium dioxide, etc. According to the use requirements of the catalyst, suitable additives can be added, such as one or more of fluorine, phosphorus, boron, magnesium, zirconium, etc.

[0017] Further, the reaction conditions in the above method are as follows: the reaction pressure is 3MPa~20MPa, preferably 8MPa~17MPa, and the air velocity is 0.2h -1 ~4.0h -1 , preferably 0.8h -1 ~2.0h -1 The reaction temperature is 260°C~430°C, preferably 300°C~400°C.

[0018] In the method of the present invention, the molar concentration of nickel atoms on the surface of the hydroprocessing catalyst is detected by XPS analysis method, and the molar concentration of nickel atoms on the surface of the hydroprocessing catalyst is generally in the range of 0.1% to 10%, preferably 0.5% to 2.5%.

[0019] Furthermore, the hydroprocessing catalyst with different surface nickel atom concentrations in the above method can be prepared using commercial products or any existing catalyst adjustment technology. For example, more nickel elements are introduced in the preparation of the catalyst, different inorganic or organic additives are introduced in the preparation process of the carrier and the catalyst, and the heat treatment temperature of the catalyst is changed to improve the distribution of nickel atoms. Taking the introduction of different inorganic or organic additives in the preparation process of the carrier and the catalyst as an example, the inorganic additive is one or more of fluorine, silicon, phosphorus, boron, magnesium, zirconium, etc., and the organic additive is one or more of nitrogen-containing organic compounds, sulfur-containing organic compounds and oxygen-containing organic compounds. The inorganic or organic additive can be introduced in any step, such as before, at the same time, and after the impregnation of the Group VIB and Group VIII metal components. The nitrogen-containing organic compound is an organic substance containing at least one covalently bonded nitrogen atom, such as ethanolamine, diethanolamine, triethanolamine, ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid (NTA) and ethylenediaminetetraacetic acid. The sulfur-containing organic compound is an organic substance containing at least one covalently bonded sulfur atom, such as mercaptan (general formula R-SH), thioether (general formula R-S-R), disulfide (general formula R-S-S-R), and R in these sulfur-containing compounds is an alkyl group containing 1 to 10 carbon atoms, such as ethyl mercaptan, ethylpropyl sulfide, dimethyl disulfide, etc. The sulfur-containing organic compound may contain one or more carboxyl, carbonyl, ester, ether, hydroxyl, and thiol group substitutions, such as thioglycolic acid, thiopropionic acid, dimercaptopropanol, etc. In addition to the above-mentioned sulfur-containing compounds, sulfone and sulfoxide compounds may be included, such as dimethyl sulfoxide, dimethyl sulfone, etc. The oxygen-containing organic compound is an organic substance containing at least one carbon atom and one oxygen atom. The oxygen-containing part may be a carboxyl, carbonyl, hydroxyl part, or a combination thereof. These substances can be acids, such as acetic acid, oxalic acid, malonic acid, tartaric acid, malic acid, citric acid, etc., alcohols, such as ethylene glycol, propylene glycol, butylene glycol, glycerol, trimethylolethane, etc., ethers, such as diethylene glycol, dipropylene glycol, triethylene glycol, tributylene glycol, tetraethylene glycol, polyethylene glycol, etc., sugars, such as glucose, fructose, lactose, maltose, sucrose, etc., and ketones, phenols, aldehydes and lipids. Different drying and / or calcination heat treatment temperatures also have an important influence on the surface nickel atom concentration of the hydroprocessing catalyst. When treated at low temperature, the surface nickel atom concentration of the hydroprocessing catalyst with the same nickel element mass content is higher; when treated at high temperature, the surface nickel atom concentration of the hydroprocessing catalyst with the same nickel element mass content is lower. The low temperature and high temperature are relative, and the treatment temperature range is 80°C~700°C. For example, you can customize the heat treatment temperature of 80°C~300°C, preferably 120°C~200°C as low temperature treatment; the heat treatment temperature of 350°C~800°C, preferably 400°C~600°C is considered as high temperature treatment.

[0020] The method of the present invention adopts different heat treatment methods to have different surface nickel atomic concentrations. The catalyst adopts high-temperature heat treatment method, the surface nickel atomic concentration is relatively low, and the reaction effect is good at low temperature; the catalyst adopts low-temperature heat treatment method, the surface nickel atomic concentration is relatively high, and the reaction effect is good at high temperature. The temperature in the logistics direction of the reactor rises gradually. This graded loading method of the catalyst is conducive to improving the overall denitrification effect of the device, and also improves the hydrogenation saturation performance of the catalyst system. DETAILED DESCRIPTION

[0021] X-ray photoelectron spectroscopy (XPS) was performed using a Multilab 2000 spectrometer produced by Thermo Fisher Scientific (VG), with an excitation source of MgKα and an analysis chamber vacuum of more than 10 -6 Pa, with C1s (284.6ev) as the internal standard, corrected for nuclear power effects. The ratio of the atomic concentration of each species on the sample surface is obtained by converting the XPS peak area of ​​the measured species according to the Wagner sensitivity factor. (Molar content of target element = number of atoms of target element / number of atoms of all elements on the catalyst surface*100%).

[0022] The detailed process of the present invention is further described below by way of examples, but the present invention should not be considered to be limited to these examples. Unless otherwise specified, % in the following examples and comparative examples are all mass percentages. The pore structure of the alumina carrier used in the examples and comparative examples is shown in Table 1.

[0023] Table 1 Physical and chemical properties of carriers

[0024]

[0025] Example 1

[0026] This example gives the preparation method of the catalyst used in the examples and comparative examples, but the following preparation method is not the only one and does not constitute a limitation to the present invention. The main properties of the prepared oxidized catalyst are shown in Table 2.

[0027] Preparation method of catalyst A: impregnate alumina carrier Z with equal volumes of impregnation solution containing Mo and Ni, the impregnation solution contains diethylene glycol, and the molar ratio of diethylene glycol to nickel atoms is 1:1. After drying at 120°C for 3h and calcining at 550°C for 2h, the obtained catalyst is recorded as A.

[0028] Preparation method of catalyst B: impregnate alumina carrier Z with equal volumes of impregnation solution containing Mo and Ni, the impregnation solution contains diethylene glycol, and the molar ratio of diethylene glycol to nickel atoms is 1:1. After drying at 120°C for 3h and calcining at 450°C for 2h, the obtained catalyst is recorded as B.

[0029] Preparation method of catalyst C: impregnate alumina carrier Z with equal volumes of impregnation solution containing Mo and Ni, the impregnation solution contains diethylene glycol, the molar ratio of diethylene glycol to nickel atoms is 1:1, and dry at 120°C for 3h. The obtained catalyst is recorded as C.

[0030] Table 2 Physicochemical properties of catalysts

[0031]

[0032] Example 2

[0033] This example provides a loading scheme for evaluating the catalyst. Three reaction beds are set along the direction of the reactant flow, with bed volumes of 10 mL, 30 mL and 60 mL, respectively, and the reaction temperatures are controlled at 350°C, 350°C and 380°C, respectively.

[0034] The test number is PS1: the three reaction beds are sequentially loaded with catalyst A, catalyst B and catalyst C along the direction of reactant flow.

[0035] The test number is PS2: the three reaction beds are sequentially loaded with catalyst A, catalyst A and catalyst C along the direction of reactant flow.

[0036] The test number is PS3: the three reaction beds are sequentially loaded with catalyst B, catalyst B and catalyst C along the direction of the reactant flow.

[0037] Comparative Example 1

[0038] This comparative example provides a loading scheme for evaluating the catalyst. Three reaction beds are set along the direction of the reactant flow, with bed volumes of 10 mL, 30 mL and 60 mL respectively, and the reaction temperatures are controlled at 350°C, 350°C and 380°C respectively.

[0039] The test number is PD1: the three reaction beds are sequentially loaded with catalyst C, catalyst B and catalyst A along the direction of reactant flow.

[0040] The test number is PD2: the three reaction beds are sequentially loaded with catalyst B, catalyst B and catalyst B along the direction of reactant flow.

[0041] The test number is PD3: the three reaction beds are sequentially loaded with catalyst C, catalyst C and catalyst C along the direction of reactant flow.

[0042] Example 3

[0043] This example is an activity evaluation experiment of the catalyst.

[0044] The catalyst activity evaluation experiment was carried out on a three-tube series small hydrogenation unit. The catalyst was presulfurized before the activity evaluation. The catalyst evaluation conditions were a total reaction pressure of 14.5 MPa and a liquid hourly space velocity of 1.0 h-1 , hydrogen-to-oil volume ratio is 1000:1, the properties of the raw oil used in the activity evaluation experiment are shown in Table 3, and the activity evaluation results are shown in Table 4.

[0045] Table 3 Raw oil properties

[0046]

[0047] Table 4500 hours catalyst activity evaluation results

[0048]

[0049] It can be seen from the 500-hour catalyst activity evaluation results in Table 4 that, compared with the comparative example, the denitrification activity of the catalyst system is greatly improved by using the loading method of the hydroprocessing catalyst of the present invention, and the aromatic saturation performance is also better, which can provide high-quality feed for the hydrocracking stage.

Claims

1. A grading method for a hydroprocessing catalyst, characterized in that: The grading method comprises loading M kinds of hydroprocessing catalysts along the flow direction of the logistics, wherein M is at least 2, the molar concentration of nickel atoms on the surface of the M-th hydroprocessing catalyst is higher than the molar concentration of nickel atoms on the surface of the M-1 hydroprocessing catalyst, and the average reaction temperature of the M-th hydroprocessing catalyst bed is higher than the average reaction temperature of the first hydroprocessing catalyst bed; the molar concentration of nickel atoms on the surface of the M-th hydroprocessing catalyst is 3%-80% higher than the molar concentration of nickel atoms on the surface of the M-1 hydroprocessing catalyst, and the average reaction temperature of the M-th hydroprocessing catalyst is 10°C-60°C higher than the average reaction temperature of the first hydroprocessing catalyst; The hydroprocessing catalyst contains active metal components of Group VIB and Group VIII; the active metal of Group VIB is W and / or Mo, and the active metal of Group VIII is Ni and / or Co. The active metal content of the active metal oxide of Group VIB in the final hydroprocessing catalyst is 9% to 50% by weight of the oxide, and the content of the active metal oxide of Group VIII is 1% to 15%.

2. The method according to claim 1, characterized in that: The molar concentration of nickel atoms on the surface of the Mth hydroprocessing catalyst is 5%-30% higher than the molar concentration of nickel atoms on the surface of the M-1st hydroprocessing catalyst, and the average reaction temperature of the Mth hydroprocessing catalyst is 20°C-50°C higher than the average reaction temperature of the 1st hydroprocessing catalyst.

3. The method according to claim 1, characterized in that: The grading method loads M types of hydroprocessing catalysts along the flow direction of the logistics, and the M is at least 3.

4. The method according to claim 1, characterized in that: The grading method loads M types of hydroprocessing catalysts along the flow direction of the logistics, wherein M is 3-7.

5. The method according to claim 3, characterized in that: When M is 3, the average reaction temperature of the M-1th hydroprocessing catalyst bed is higher than or equal to the average reaction temperature of the M-2th hydroprocessing catalyst bed.

6. The method according to claim 3, characterized in that: When M is 3, the average reaction temperature of the M-1th hydroprocessing catalyst bed is 10° C.-40° C. higher than the average reaction temperature of the M-2th hydroprocessing catalyst bed.

7. The method according to claim 1, characterized in that: The loading volume ratio of adjacent different types of catalysts is 1:20~20:

1.

8. The method according to claim 1, characterized in that: The loading volume ratio of adjacent different types of catalysts is 1:10~10:

1.

9. The method according to claim 1, characterized in that: The loading volume ratio of adjacent different types of catalysts is 1:5~5:

1.

10. The method according to claim 1, characterized in that: The raw materials processed by the method are various diesels, VGO, CGO, DAO and mixed oils of two or more thereof.

11. The method according to claim 10, characterized in that: The properties of the raw materials are as follows: distillation range, initial distillation point greater than 180°C, final distillation point less than 600°C; density at 20°C 0.8000~0.9500 / g·cm -3 ; Nitrogen content 100~6000μg·g -1 ; Sulfur content 0.05%~3.0%.

12. The method according to claim 1, characterized in that: The catalyst carrier is one or more of alumina, silica, silica-alumina, magnesia, zirconia, boria and titanium dioxide.

13. The method according to claim 1, characterized in that: The reaction conditions are as follows: reaction pressure is 3MPa~20MPa, space velocity is 0.2h -1 ~4.0h -1 , the reaction temperature is 260℃~430℃.

14. The method according to claim 13, characterized in that: The reaction conditions are as follows: reaction pressure is 8MPa~17MPa, space velocity is 0.8h -1 ~2.0h -1 , the reaction temperature is 300℃~400℃.

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