A catalyst grading method

Abstract

The present invention discloses a catalyst (preferably a hydroprocessing catalyst) grading method, wherein the interaction between active metal and carrier is decreasing along the flow direction of the material flow, and the hydroprocessing reaction temperature is increasing. The catalyst grading method is applicable to the hydroprocessing process of various distillate oils, and improves the overall desulfurization and denitrification performance of the hydroprocessing reactor.

Description

Technical Field

[0001] The invention relates to a catalyst grading method, in particular to a catalyst grading method 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] CN101591566A relates to a catalyst grading method for deep hydrodesulfurization of diesel, wherein the raw oil is mixed with hydrogen and then enters a hydrogenation reactor for hydrogenation reaction, and the reaction effluent is cooled and separated to obtain hydrogen-rich gas and liquid products, and the hydrogenation reactor has four hydrogenation reaction zones in sequence, wherein a hydrogenation protective agent is loaded in the first hydrogenation reaction zone, a hydrorefining catalyst I containing active metal cobalt-molybdenum is loaded in the second hydrogenation reaction zone, a mixture of hydrorefining catalyst I and hydrorefining catalyst II is loaded in the third reaction zone, and a hydrorefining catalyst II containing active metal nickel-tungsten is loaded in the fourth reaction zone. The present invention reasonably grades catalysts of different systems, gives full play to the advantages of each catalyst in different desulfurization stages, improves the overall catalyst activity through the synergistic effect between each catalyst, and can obtain ultra-low sulfur diesel with sulfur content meeting Euro IV standards under relatively mild operating conditions.

[0006] CN111196934A relates to a grading method for a heavy oil hydroprocessing catalyst, wherein a reactor is sequentially loaded with a hydrodemetallization catalyst, a hydrodesulfurization catalyst and a hydrodenitrification catalyst from top to bottom, and the raw material flow is from top to bottom, and is maintained along the flow direction, the catalyst activity gradually increases, the pore size gradually decreases, the particle size gradually decreases, and the porosity gradually decreases; the hydrodemetallization catalyst, the hydrodesulfurization catalyst and the hydrodenitrification catalyst are independently composed of one or more catalysts, and the active metal MoS2 in the hydrodemetallization catalyst, the hydrodesulfurization catalyst and the hydrodenitrification catalyst after sulfidation is highly dispersed, and the MoS2 in the hydrodemetallization catalyst after sulfidation is mainly dispersed in a single layer and a double layer, and the MoS2 in the hydrodesulfurization catalyst after sulfidation is mainly dispersed in a double layer. The catalyst grading combination obtained by the method has high demetallization, residual carbon removal, desulfurization, and denitrification activity and stability, and a long service life.

[0007] The existing technologies mostly study the grading of catalyst activity and catalyst particle size, without considering the influence of catalyst active phase preparation technology on catalyst grading performance, especially for hydrodesulfurization and hydrodenitrogenation reactions, the surface properties of the catalyst have an important influence. Summary of the invention

[0008] 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 improve the overall desulfurization and denitrification performance of the hydroprocessing reactor.

[0009] A catalyst (preferably a hydroprocessing catalyst) grading method, wherein the interaction between active metal and carrier is decreasing along the flow direction of the material flow, and the hydroprocessing reaction temperature is increasing.

[0010] In the above method, M types of hydroprocessing catalysts are loaded along the flow direction of the logistics, wherein M is at least 2, preferably M is at least 3, and more preferably M is 3-7. Specifically, M can be 2, 3, 4 or 5, and preferably M is 3.

[0011] In the above method, the strength of the interaction between the catalyst active metal and the carrier is determined by the H2-TPR method, and the peak temperature of hydrogen consumption represents the strength of the interaction. The lower the peak temperature, the weaker the interaction. The peak temperature range is between 230°C and 480°C, preferably between 280°C and 450°C.

[0012] In the above method, the peak temperature of hydrogen consumption of the Mth hydroprocessing catalyst is lower than the peak temperature of hydrogen consumption of the first hydroprocessing catalyst, preferably 10°C-80°C lower, and the average reaction temperature of the Mth hydroprocessing catalyst is higher than the average reaction temperature of the first hydroprocessing catalyst, preferably 20°C-60°C higher.

[0013] Furthermore, when the M in the above method is at least 3, the average reaction temperature of the M-1th hydroprocessing catalyst is higher than or equal to the average reaction temperature of the M-2th hydroprocessing catalyst, preferably higher than 10°C-50°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] Furthermore, the hydroprocessing catalyst with different interaction strengths between active metals and carriers in the above method can be commercially available or prepared by any existing catalyst adjustment technology. For example, different inorganic or organic additives are introduced during the preparation of carriers and catalysts, and the heat treatment temperature of the catalyst is changed. Taking the introduction of different inorganic or organic additives during the preparation of carriers and catalysts as an example, the inorganic additives are one or more of fluorine, silicon, phosphorus, boron, magnesium, zirconium, etc. 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 at any step, such as before, at the same time, and after the impregnation of 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., ketones, phenols, aldehydes and lipids. Different drying and / or calcination heat treatment temperatures also have an important influence on the strength of the interaction between the active metal and the support of the hydroprocessing catalyst. When treated at low temperatures, the interaction between the active metal and the support is weak; when treated at high temperatures, the interaction between the active metal and the support of the hydroprocessing catalyst is strong. The low temperature and high temperature are relative, and the treatment temperature range is 80°C~800°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.

[0019] When the method of the present invention is adopted, when the metal carrier interacts strongly, the obtained active phase has a strong ability to dissociate hydrogen, and the reaction effect is good at low temperature; when the metal carrier interacts weakly, the active phase has a strong ability to transfer hydrogen, and the reaction effect is good at high temperature. The graded loading method of the catalyst of the present invention is conducive to improving the overall desulfurization and denitrification effect of the device. DETAILED DESCRIPTION

[0020] H2-TPR characterization was performed using a fully automatic chemisorption instrument (AMI-200) from Altamira, USA. The carrier gas was high-purity argon, and the sample was pretreated at 485°C for 1 h before the measurement. Then 5% H2-Ar was used as the reaction gas and the temperature was programmed to 700°C at a heating rate of 10°C / min.

[0021] 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. In the following examples and comparative examples, % are all mass percentages unless otherwise specified.

[0022] The pore structure of the alumina carrier used in the examples and comparative examples is shown in Table 1:

[0023] Table 1 Properties of carriers used in the examples and comparative examples

[0024]

[0025] Example 1

[0026] This example provides 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.

[0027] Preparation method of catalyst C1: The alumina carrier Z1 was impregnated with equal volumes of impregnation solution containing Mo and Ni, dried at 120°C for 3h, and calcined at 550°C for 2h. The obtained catalyst was recorded as C1.

[0028] Preparation method of catalyst C2: The alumina carrier Z2 is impregnated with equal volumes of impregnation solution containing Mo and Ni, dried at 120°C for 3 hours, and calcined at 450°C for 2 hours. The obtained catalyst is recorded as C2.

[0029] Preparation method of catalyst C3: impregnate alumina carrier Z2 with equal volumes of impregnation solution containing Mo and Ni, the impregnation solution contains citric acid, the molar ratio of citric acid to nickel atoms is 0.3:1, and dry at 120°C for 3h. The obtained catalyst is recorded as C3.

[0030] Table 2 Main properties of the prepared oxidized 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 20 mL, 20 mL and 60 mL, respectively, and the reaction temperatures are controlled at 340°C, 340°C and 380°C, respectively.

[0034] The test number is P1: along the direction of reactant flow, three reaction beds are sequentially loaded with catalyst C1, catalyst C2 and catalyst C3.

[0035] The test number is P2: along the direction of reactant flow, the three reaction beds are sequentially loaded with catalyst C1, catalyst C1 and catalyst C3.

[0036] The test number is P3: along the direction of the reactant flow, the three reaction beds are sequentially loaded with catalyst C2, catalyst C2 and catalyst C3.

[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 20 mL, 20 mL and 60 mL, respectively, and the reaction temperatures are controlled at 340°C, 340°C and 380°C, respectively.

[0039] The test number is P4: the three reaction beds are sequentially loaded with catalyst C3, catalyst C2 and catalyst C1 along the direction of reactant flow.

[0040] The test number is P5: along the direction of reactant flow, the three reaction beds are sequentially loaded with catalyst C2, catalyst C2 and catalyst C2.

[0041] The test number is P6: along the direction of reactant flow, the three reaction beds are sequentially loaded with catalyst C3, catalyst C3 and catalyst C3.

[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 15.0 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 4 500-hour catalyst activity evaluation results

[0048]

[0049] It can be seen from the evaluation results in Table 4 that, compared with the comparative example, the denitrification and desulfurization activities of the catalyst system are greatly improved by using the loading method of the hydroprocessing catalyst of the present invention, and high-quality feed can be provided for subsequent devices.

Claims

1. A grading method for a hydroprocessing catalyst, characterized in that: M kinds of hydroprocessing catalysts are loaded along the flow direction of the logistics, wherein M is at least 2; the interaction between the active metal in the catalyst and the carrier is decreasing along the flow direction of the logistics, and the hydroprocessing reaction temperature is increasing; the strength of the interaction between the active metal in the catalyst and the carrier is determined by the H2-TPR method, and the peak temperature of hydrogen consumption is used to represent the strength of the interaction, and the peak temperature is 230°C to 480°C, and the peak temperature of hydrogen consumption of the Mth hydroprocessing catalyst is 10°C to 80°C lower than the peak temperature of hydrogen consumption of the first hydroprocessing catalyst; the average reaction temperature of the Mth hydroprocessing catalyst is 20°C to 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, wherein 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: M types of hydroprocessing catalysts are loaded along the flow direction of the logistics, and the M is at least 3.

3. The method according to claim 1, characterized in that: M kinds of hydroprocessing catalysts are loaded along the flow direction of the logistics, wherein M is 3-7.

4. The method according to claim 1, characterized in that: The strength of the interaction between the active metal of the catalyst and the carrier is determined by the H2-TPR method, and the peak temperature of hydrogen consumption is used to represent the strength of the interaction. The peak temperature is 280℃~450℃.

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

6. The method according to claim 1, characterized in that: The average reaction temperature of the M-1th hydroprocessing catalyst is 10°C-50°C higher than the average reaction temperature of the M-2th hydroprocessing catalyst.

7. The method according to claim 1, characterized in that: The packing volume ratio of adjacent catalyst beds is 1:20~20:

1.

8. The method according to claim 1, characterized in that: The packing volume ratio of adjacent catalyst beds is 1:10~10:

1.

9. The method according to claim 1, characterized in that: The packing volume ratio of adjacent catalyst beds is 1:5~5:

1.

10. The method according to claim 1, characterized in that: The properties of the raw materials treated by the method 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 0.05wt%~3.0wt%.

11. 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℃.

12. The method according to claim 1, 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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