Method for producing high-octane gasoline by catalyzing diesel oil hydrocracking

Abstract

The invention relates to the field of gasoline production by catalyzing diesel oil hydrocracking, and discloses a method for producing high-octane gasoline by catalyzing diesel oil hydrocracking. The method comprises the following steps: under the action of passivated raw oil, hydrogen and a passivation auxiliary agent, passivating a hydrofining catalyst and a hydrocracking catalyst, along a material flow direction, filling the upstream of the hydrocracking catalyst with the hydrofining catalyst, filling n catalyst bed layers connected in series with the hydrofining catalyst and the hydrocracking catalyst, the passivation auxiliary agents are injected into the n catalyst bed layers connected in series respectively, and n is a positive integer and is larger than or equal to 2; switching the passivated raw oil into catalytic diesel oil, then stopping injecting the passivating auxiliary agent, and reducing the injection amount of the passivating auxiliary agent until the injection is stopped; the mixed material containing the catalytic diesel oil and the passivation additive and hydrogen are sequentially contacted with a passivation hydrofining catalyst and a passivation hydrocracking catalyst, and gasoline is obtained. The method can greatly shorten the cycle that the octane number of the gasoline product reaches the standard at the initial stage of start-up.

Description

Technical Field

[0001] The present invention relates to the field of catalytic diesel hydrocracking for gasoline production, and particularly to a method for catalytic diesel hydrocracking to produce high-octane gasoline. Background Art

[0002] As one of the main processes for heavy oil upgrading, fluid catalytic cracking (FCC) technology occupies an important position in refineries around the world. In recent years, with the increasing heaviness and inferiority of the feedstocks processed by FCC units, the quality of FCC products, especially fluid catalytic cracking light cycle oil (LCO), has further deteriorated. LCO has high sulfur and aromatic hydrocarbon contents and poor engine ignition performance, and is mainly used for blending fuel oil, non-vehicle diesel, and heating oil abroad. How to convert aromatics in LCO into high-octane fuels with high added value has been the research direction for many years. At present, the main approach of each licensor is to moderately crack and shallowly hydrogenate LCO to convert it into high-octane fuels, but there is a problem that the hydrogenation depth affects the loss of octane number during the hydroconversion of catalytic diesel.

[0003] There have been relevant reports at home and abroad on using hydrocracking process technology to convert fluid catalytic cracking light cycle oil into ultra-low sulfur diesel and high-octane gasoline blending components. For example: At the 1995 NPRA annual meeting, David A. Pappal et al. introduced the MAK-LCO technology developed by Mobil, Akzo Nobel, and M.W. Kellogg companies; at the 2005 NPRA annual meeting, Vasant P. Thakkar et al. introduced the LCO UnicrackingTM technology and HC-190 special catalyst developed by UOP. It is reported that both of the above two technologies can convert low-value catalytic cycle oil components into high-octane gasoline components and high-quality diesel blending components. In addition, at the 2007 NPRA annual meeting, UOP introduced its developed LCO-X new technology, which realized a new way to increase aromatics production using catalytic light cycle oil through a hydroconversion-selective alkylation transfer route. It can be seen from this that the utilization of relatively low-value catalytic light cycle oil has been upgraded from the initial upgrading to the level of producing oils and chemicals with higher added value.

[0004] At present, the catalytic diesel hydroconversion units in operation in China generally have problems that in the initial stage of unit startup, affected by the relatively high initial activity of the catalyst, the catalyst system shows strong capabilities in hydrodesulfurization, denitrification, and dearomatization, and the hydrocracking catalyst also has high hydrogenation performance, but there is a poor matching of hydrogenation activity and cracking activity in the initial stage. As a result, the octane number of gasoline components in the initial stage of startup is not high and cannot meet the production requirements, and it takes a long time to stabilize before meeting the requirements for producing high-grade octane gasoline.

[0005] US4971680 discloses a method for hydrocracking aromatics in diesel oil using a hydrocracking catalyst. This method adopts a single-stage series process to selectively crack bicyclic aromatics into gasoline components, but the octane number of the gasoline product is low and still requires further treatment.

[0006] CN111088073A discloses a hydrocracking method for catalytic diesel. This method adopts a two-stage hydrocracking process, and by controlling the H2S and NH3 concentrations in the hydrofining reactor and the hydrocracking reactor in sections, the purpose of shortening the stabilization time at the initial stage of startup and extending the operation cycle of the device is achieved. However, the synergistic effect of the catalyst hydrogenation and cracking reactions is not considered.

[0007] CN114686259A discloses a method for catalytic diesel hydrogenation conversion with catalyst grading. This method adopts a single-stage series process. The catalytic diesel raw material and hydrogen enter the hydrofining reaction zone, and the effluent directly enters the hydrocracking reactor, successively passing through more than two hydrocracking catalyst beds for hydrogenation conversion reactions; in the hydrofining reaction zone, along the material flow direction, the mass fraction of nickel oxide in the hydrofining catalyst decreases, the mass fraction of cobalt oxide increases, the mass fraction of molybdenum oxide increases, and the total mass fraction of active metals increases. The present invention achieves the maximum retention of monocyclic aromatics in the refined oil and improves the octane number of the gasoline product by grading the hydrofining catalysts in different reaction zones of the catalytic diesel hydrogenation conversion. However, the problem of relatively high catalyst activity at the initial stage of device startup is not considered, and the device adjustment time cannot be shortened. Summary of the Invention

[0008] The object of the present invention is to overcome the problems existing in the prior art and provide a method for catalytic diesel hydrocracking to produce high-octane gasoline. This method can greatly shorten the period for the octane number of the gasoline product to reach the standard at the initial stage of startup.

[0009] To achieve the above object, on the one hand, the present invention provides a method for catalytic diesel hydrocracking to produce high-octane gasoline, which includes the following steps:

[0010] (1) Under the action of a passivation feedstock oil, hydrogen, and a passivation aid, a passivation reaction is carried out on the hydrofining catalyst and the hydrocracking catalyst to obtain a passivated hydrofining catalyst and a passivated hydrocracking catalyst. Among them, along the material flow direction, the hydrofining catalyst is loaded upstream of the hydrocracking catalyst, and the hydrofining catalyst and the hydrocracking catalyst are jointly loaded in n series-connected catalyst beds, and the passivation aid is respectively injected into the n series-connected catalyst beds, where n is a positive integer and n≥2;

[0011] (2) After the passivation reaction is completed, the passivation feedstock oil is switched to catalytic diesel, and the injection amount of the passivation aid is reduced until it stops;

[0012] (3) The mixed material containing catalytic diesel and a passivation aid and hydrogen are successively contacted with a passivated hydrofining catalyst and a passivated hydrocracking catalyst to respectively carry out a hydrofining reaction and a hydrocracking reaction to obtain gasoline.

[0013] Through the above technical solution, the beneficial effects of the present invention include:

[0014] In the method provided by the present invention, a specific passivation process is adopted to simultaneously carry out a passivation reaction on the hydrofining catalyst and the hydrocracking catalyst, realizing the synchronous passivation of the catalysts in each bed layer, which is more conducive to exerting the cracking activity, reducing its hydrogenation performance, matching the activities of the hydrofining catalyst and the hydrocracking catalyst, and greatly shortening the time for the octane number of the gasoline product to meet the requirements of the national standard gasoline with an octane number of 92. Specific embodiments

[0015] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0016] The present invention provides a method for rapidly producing high-octane gasoline by hydrocracking of catalytic diesel, and the method includes the following steps:

[0017] (1) Under the action of a passivation feedstock oil, hydrogen and a passivation aid, a passivation reaction is carried out on a hydrofining catalyst and a hydrocracking catalyst to obtain a passivated hydrofining catalyst and a passivated hydrocracking catalyst. Among them, along the material flow direction, the hydrofining catalyst is loaded upstream of the hydrocracking catalyst, and the hydrofining catalyst and the hydrocracking catalyst are jointly loaded in n series-connected catalyst beds, and the passivation aid is respectively injected into the n series-connected catalyst beds, n is a positive integer, and n≥2;

[0018] (2) After the passivation reaction is completed, the passivation feedstock oil is switched to catalytic diesel, and the injection amount of the passivation aid is reduced until it stops;

[0019] (3) The mixed material containing catalytic diesel and a passivation aid and hydrogen are successively contacted with a passivated hydrofining catalyst and a passivated hydrocracking catalyst to respectively carry out a hydrofining reaction and a hydrocracking reaction to obtain gasoline.

[0020] In the present invention, the hydrofining catalyst and the hydrocracking catalyst may be respectively loaded into two series-connected passivation reactors, or may be loaded into one passivation reactor. To reduce the investment in equipment modification, minimize the change of the process flow, and reduce the engineering cost, preferably, the hydrofining catalyst and the hydrocracking catalyst are loaded into one passivation reactor.

[0021] The present invention does not particularly limit the type selection of the passivation reactor, and various passivation reactors that can achieve the passivation process described in the present invention can be used. The present invention preferably uses a hydrogenation reactor as the passivation reactor. Preferably, the passivation process is carried out in a hydrogenation reactor, preferably in a trickle-bed reactor. By adopting this preferred embodiment, the existing hydrogenation reaction process device can be directly used, which can shorten the adjustment time for the octane number of gasoline products to reach the qualified level during the initial startup period, reduce investment, save costs, and improve economic efficiency.

[0022] According to the present invention, preferably, n is 2 - 15, preferably 4 - 10, and n is a positive integer. By adopting this preferred embodiment, the problems of uneven catalyst passivation and poor passivation synchronism can be effectively solved, and excellent effects are achieved.

[0023] The present invention does not particularly limit the specific number of loading beds of the hydrofining catalyst and the specific number of loading beds of the hydrocracking catalyst, and can be appropriately selected according to different application scenarios and actual requirements.

[0024] Preferably, the number of loading beds of the hydrofining catalyst is 1 - 6, preferably 2 - 4.

[0025] Preferably, the number of loading beds of the hydrocracking catalyst is 2 - 8, preferably 2 - 6.

[0026] To improve the passivation effect, the injection amount of the passivation aid in different catalyst beds mainly adopts the following two methods:

[0027] Method 1: Along the material flow direction, the injection mass of the passivation aid in n catalyst beds is equal.

[0028] Method 2: Along the material flow direction, the injection mass of the passivation aid in n catalyst beds gradually decreases.

[0029] The present invention preferably injects the passivation aid by Method 2. By adopting this preferred embodiment, it is more conducive to the initial activity regulation of the catalysts in each reaction zone, realizes the controllable carbon deposition process of the catalysts, matches the activities of the hydrofining catalyst and the hydroconversion catalyst, and achieves the purpose of shortening the time for the octane number of gasoline products to reach the qualified level.

[0030] According to the present invention, preferably, along the logistics direction, with respect to the injection mass of the passivation aid in the previous catalyst bed, the injection amount of the passivation aid in the n catalyst beds decreases successively by 3-20% by weight, preferably 3-10% by weight. For example, it can be 3%, 5%, 7%, 10%, 12%, 15%, 17%, 20%, and any value within the range formed by any two of these point values. Adopting this preferred embodiment further facilitates the initial activity regulation of the catalysts in each reaction region.

[0031] It should be noted that the percentage reduction of the above-mentioned passivation aid is calculated as follows:

[0032] The percentage reduction of the passivation aid in the current catalyst bed = (the injection mass of the passivation aid in the previous catalyst bed - the injection mass of the passivation aid in the current catalyst bed) / the injection mass of the passivation aid in the previous catalyst bed × 100%.

[0033] For example: the injection amount of the passivation aid in the second catalyst bed is 20% of the total injection amount of the passivation aid, and the injection amount of the passivation aid in the first catalyst bed is 25% of the total injection amount of the passivation aid, with a reduction of 20%.

[0034] In the present invention, for different catalyst beds, the percentage reduction of the above-mentioned passivation aid can be equal or unequal.

[0035] Preferably, along the logistics direction, based on the total injection mass of the passivation aid, the injection amount of the passivation aid in the first catalyst bed is 15-35% by weight. For example, it can be 15% by weight, 18% by weight, 20% by weight, 23% by weight, 25% by weight, 28% by weight, 30% by weight, 33% by weight, 35% by weight, and any value within the range formed by any two of these point values. Adopting this preferred embodiment is beneficial to further improving the passivation effect.

[0036] According to the present invention, preferably, along the logistics direction, the passivation feedstock oil and hydrogen flow from the first catalyst bed to the nth catalyst bed.

[0037] It can be understood that the introduction methods of the passivation feedstock oil and hydrogen are different from that of the passivation aid.

[0038] According to the present invention, preferably, both the hydrofining catalyst and the hydrocracking catalyst in step (1) are catalysts after sulfidation treatment.

[0039] The present invention does not particularly limit the method of the sulfidation treatment. It can be the presulfidation method commonly used in the art or the true sulfidation method commonly used in the art. The present invention does not make a special limitation on this.

[0040] According to the present invention, preferably, the initial boiling point of the passivation feedstock oil is 155 - 330 °C, preferably 170 - 250 °C, and the final boiling point is 350 - 420 °C.

[0041] According to the present invention, preferably, in the passivation feedstock oil, the aromatic hydrocarbon content is less than 35 wt%, preferably 15 - 32 wt%.

[0042] According to the present invention, preferably, in the passivation feedstock oil, the organic nitrogen content is less than 250 μg / g, preferably 50 - 180 μg / g.

[0043] Using the passivation feedstock oil having the above characteristics is more conducive to achieving the passivation of the catalyst.

[0044] The present invention has a relatively wide selection range for the specific type of the passivation feedstock oil, and any feedstock oil that meets the above characteristic requirements can be used. Preferably, the passivation feedstock oil is a heavy diesel fraction, preferably selected from at least one of the second normal distillate, the third normal distillate, the fourth normal distillate, the reduced top oil, the first reduced oil, and straight-run diesel, and more preferably selected from at least one of the fourth normal distillate, the reduced top oil, and the first reduced oil. Adopting this preferred embodiment is more conducive to making full use of the characteristics of the relatively high proportion of heavier components in the feedstock but less coke-forming substances, giving full play to the activity of the catalyst, and achieving the effect of moderately reducing (regulating) the activity of the catalyst (moderate carbon deposition and avoiding excessive carbon deposition).

[0045] According to the present invention, preferably, the passivation aid is a sulfide, preferably selected from at least one of di-tert-butyl sulfide, di-tert-butyl disulfide, di-tert-butyl polysulfide, tert-nonyl polysulfide, tert-dodecyl polysulfide, diphenyl sulfide, diphenyl disulfide, diphenyl polysulfide, and di-tert-nonyl sulfide. Using the above specific type of passivation aid enables the passivation aid to decompose into small hydrocarbon molecules and H 2 S in the hydrogen atmosphere, which is more conducive to the step-by-step carbon deposition in the catalyst passivation process and the synchronous carbon deposition of the catalysts in each bed layer, achieving the goal of avoiding excessive carbon deposition of the catalyst, ensuring the matching of the hydrogenation and conversion performance of the catalyst, and at the same time avoiding the situation where the operating pressure of the recycle hydrogen compressor is too low and the compressor cannot operate.

[0046] According to the present invention, preferably, the conditions for the passivation reaction of the hydrofining catalyst and the passivation reaction of the hydrocracking catalyst in step (1) independently include: the temperature is 300 - 360 °C, preferably 315 - 355 °C; the volume space velocity is 0.2 - 6 h -1 , preferably 0.5 - 4 h -1; The hydrogen-to-oil volume ratio is 200 - 2000:1, preferably 500 - 1500:1; the passivation time is 36 - 108 h, preferably 40 - 80 h. Adopting this preferred implementation method is more conducive to the catalyst to realize the co-passivation process according to the actual reaction situation in the reaction zone. By adjusting the passivation time, it is more conducive to the passivation effect of the catalyst.

[0047] It should be noted that the space velocity in the above passivation reaction refers to the space velocity of the passivation feedstock oil added relative to the catalyst in the entire reactor.

[0048] To improve the passivation effect of the catalyst, preferably, the mass of the passivation aid is 0.5 - 30% of the mass of the passivation feedstock oil, preferably 5 - 30%.

[0049] The present invention does not particularly limit the filling ratio of the hydrofining catalyst and the hydrocracking catalyst in the passivation process, and it can be appropriately selected according to the needs of subsequent hydrogenation reactions, and can be selected with reference to the conventional methods in the art. Generally, the amount of passivation in the front is the same as the amount required for subsequent reactions. Preferably, the filling volume ratio of the hydrofining catalyst to the hydrocracking catalyst is 7:3 - 3:7, preferably 6:4 - 4:6.

[0050] According to the present invention, preferably, the passivation reaction in step (1) includes a first passivation reaction and a second passivation reaction.

[0051] According to the present invention, preferably, the temperature of the first passivation reaction is 3 - 30 °C higher than that of the second passivation reaction, preferably 3 - 10 °C higher.

[0052] According to the present invention, preferably, in the first passivation reaction, the mass of the passivation aid is 0.5 - 20% of the mass of the passivation feedstock oil, preferably 5 - 15%.

[0053] According to the present invention, preferably, the time of the first passivation reaction is 24 - 60 h, preferably 24 - 48 h.

[0054] According to the present invention, preferably, in the second passivation reaction, the mass of the passivation aid is 15 - 30% of the mass of the passivation feedstock oil, preferably 20 - 30%.

[0055] According to the present invention, preferably, the time of the second passivation reaction is 12 - 48 h, preferably 16 - 32 h.

[0056] Adopting the above specific two-stage passivation is more conducive to realizing the passivation of the catalyst, more conducive to exerting the cracking activity, reducing its hydrogenation performance, matching the activities of the hydrofining catalyst and the hydrocracking catalyst, and achieving the purpose of shortening the time for the octane number of gasoline products to reach the qualified level.

[0057] In step (2) of the present invention, the passivation feedstock oil is switched to catalytic diesel. To ensure the safety and controllability of the passivation process and mitigate the impact of catalyst carbon deposition after further processing of catalytic diesel and subsequent raw material deterioration, the present invention preferably switches the passivation feedstock oil to catalytic diesel in batches while reducing the dosage of the passivation aid in batches. Specifically, based on the total weight of the passivation feedstock oil and catalytic diesel, the increase ratio of catalytic diesel in each switch is 10-40 wt%.

[0058] It should be noted that the above increase ratio is the difference between the percentage of catalytic diesel in the current switch and the percentage of catalytic diesel in the previous switch. The percentage refers to the mass content of catalytic diesel based on the total weight of the passivation feedstock oil and catalytic diesel.

[0059] For example: based on the total weight of the passivation feedstock oil and catalytic diesel, the input amount of catalytic diesel in the second switch is 20%, and the injection amount of catalytic diesel in the first switch is 15%, with an increase ratio of 5%.

[0060] Preferably, based on the total weight of the passivation feedstock oil and catalytic diesel, the reduction ratio of the passivation aid in each switch is 1-20 wt%.

[0061] It should be noted that the above reduction ratio is the difference between the injection percentage of the passivation aid in the previous switch and the injection percentage of the passivation aid in the current switch. The percentage refers to the percentage of the injection mass of the passivation aid in the total weight of the passivation feedstock oil and catalytic diesel.

[0062] For example: based on the total weight of the passivation feedstock oil and catalytic diesel, the injection amount of the passivation aid in the second switch is 20%, and the injection amount of the passivation aid in the first switch is 25%, with a reduction ratio of 5%.

[0063] Preferably, the time interval between two adjacent switches of catalytic diesel is 5-15 h.

[0064] The present invention does not have any specific limitation on the number of switches, which is subject to achieving 100% switching to catalytic diesel and the content of the passivation aid meeting the following requirements.

[0065] When switching to 100% catalytic diesel, it is necessary to control the content of the passivation aid at the following specific level, which is beneficial to further adjusting the catalyst activity, avoiding excessive initial catalyst activity and over-cracking, and achieving the goal of quickly adjusting the catalyst activity to match the processing raw material. Preferably, in the mixed material, the mass of the passivation aid is 5-20% of the mass of the catalytic diesel.

[0066] It can be understood that the mass of the passivation aid here refers to: the mass of the passivation aid when switching to 100% catalytic diesel.

[0067] Preferably, switch the passivation feedstock oil to 100% catalytic diesel, and then stop injecting the passivation aid.

[0068] The present invention does not particularly limit the type of the hydrofining catalyst, which can be a conventional choice in the art. Preferably, the hydrofining catalyst includes a first carrier and a first metal component supported on the first carrier, wherein the first carrier contains a heat-resistant inorganic oxide, and the first metal component includes a Group VIB metal component and a Group VIII metal component.

[0069] According to the present invention, preferably, the heat-resistant inorganic oxide is selected from at least one of silica, alumina, amorphous silica-alumina, zirconia, and titania.

[0070] According to the present invention, preferably, based on the total weight of the hydrofining catalyst, in the hydrofining catalyst, calculated as oxides, the content of the first metal component is 15-50% by weight, preferably 18-45% by weight.

[0071] According to the present invention, preferably, based on the total weight of the first hydrocracking catalyst, in the first hydrocracking catalyst, calculated as oxides, the content of the Group VIII metal component is 1.5-8% by weight, preferably 2-6% by weight.

[0072] According to the present invention, preferably, the Group VIB metal component is Mo and / or W.

[0073] According to the present invention, preferably, the Group VIII metal component is Ni and / or Co.

[0074] The source of the hydrofining catalyst of the present invention is not particularly limited, and it can be obtained by commercial purchase or prepared by conventional methods.

[0075] The present invention does not particularly limit the type of the hydrocracking catalyst, which can be a conventional choice in the art. Preferably, the hydrocracking catalyst includes a second carrier and a second metal component supported on the second carrier, wherein the second carrier contains Y-type molecular sieve, and the second metal component includes a Group VIB metal component and a Group VIII metal component.

[0076] In the present invention, the Y-type molecular sieve can be a pure Y molecular sieve or a modified Y molecular sieve, which can be a conventional choice in the art.

[0077] According to the present invention, preferably, based on the total weight of the hydrocracking catalyst, in the hydrocracking catalyst, calculated as oxides, the content of the second metal component is 3-50% by weight, preferably 18-40% by weight.

[0078] According to the present invention, preferably, based on the total weight of the hydrocracking catalyst, the content of the Group VIII metal component in the hydrocracking catalyst is 1.5-8% by weight, preferably 2-6% by weight, calculated as the oxide.

[0079] According to the present invention, preferably, the Group VIB metal component is Mo and / or W.

[0080] According to the present invention, preferably, the Group VIII metal component is Ni and / or Co.

[0081] There is no particular limitation on the source of the hydrocracking catalyst of the present invention, and it can be obtained by commercial purchase or prepared by a conventional method.

[0082] Preferably, the initial boiling point of the catalytic diesel is 90-290 °C, preferably 100-200 °C; the final boiling point is 330-450 °C.

[0083] Preferably, in the catalytic diesel, the aromatic hydrocarbon content is ≥45 wt%, preferably 50-75 wt%.

[0084] Further preferably, in the catalytic diesel, the polycyclic aromatic hydrocarbon content is ≥35 wt%, preferably 40-60 wt%.

[0085] The present invention has no particular limitation on the specific type selection of the catalytic diesel, and it can be the product of various catalytic cracking processes obtained by processing any base oil type, as long as the above characteristics are satisfied.

[0086] The conditions of the hydrofining reaction of the present invention can be carried out with reference to the conventional methods in the art. Preferably, the conditions of the hydrofining reaction include: the reaction temperature is 280-430 °C, preferably 300-380 °C; the volume space velocity is 0.4-10 h -1 , preferably 0.5-5 h -1 ; the hydrogen-oil volume ratio is 200-2000:1, preferably 500-1500:1; the reaction pressure is 2.5-20 MPa, preferably 5-15 MPa.

[0087] The conditions of the hydrocracking reaction of the present invention can be carried out with reference to the conventional methods in the art. Further, the conditions of the hydrocracking reaction include: the reaction temperature is 310-450 °C, preferably 345-420 °C; the volume space velocity is 0.4-16 h -1 , preferably 0.5-5 h -1 , the hydrogen-oil volume ratio is 200-2000:1, preferably 500-1500:1; the reaction pressure is 2.5-20 MPa, preferably 5-15 MPa.

[0088] The present invention will be described in detail below with reference to embodiments.

[0089] In the following embodiments, the hydrofining catalyst used is the FHUDS-10 catalyst produced by Sinopec Catalyst Dalian Co., Ltd.; the hydroconversion catalyst is the FC-90 catalyst produced by Sinopec Catalyst Dalian Co., Ltd. Among them, the FHUDS-10 catalyst uses alumina as the carrier and Mo-Ni as the active components; the FC-90 catalyst uses modified Y-type molecular sieve as the carrier and W-Ni as the active metal components.

[0090] Example 1

[0091] A conventional trickle-bed hydrogenation reactor is selected. The reactor is filled with sulfided FHUDS-10 catalyst and FC-90 catalyst. Along the flow direction of the material, the hydrofining catalyst is filled upstream of the hydrocracking catalyst, and the hydrofining catalyst and the hydrocracking catalyst are filled in 5 series-connected catalyst beds. Among them, the number of catalyst beds filled with the hydrofining catalyst is 2, and the number of catalyst beds filled with the hydrocracking catalyst is 3. The filling volume ratio of the FHUDS-10 catalyst to the FC-90 catalyst is 4:6. For the first-stage passivation, the passivation feedstock oil-1 (the first reduced oil) and hydrogen in Table 1 enter the reactor and flow from the 1st catalyst bed to the 5th catalyst bed along the flow direction of the material; the injection total mass of the passivation aid (di-tert-butyl polysulfide) accounts for 10% of the mass of the passivation feedstock oil. Along the flow direction, the injection mass of the passivation aid in the first bed is 25% of the total injection mass of the passivation aid. The injection amounts of the passivation aid for the catalysts in the second bed, the third bed, the fourth bed, and the fifth bed are each reduced by 10% by weight compared with the previous bed, and are respectively injected at the inlet of each bed. The reaction temperature is adjusted to 340 °C for the hydrofining catalyst bed and 350 °C for the hydrocracking catalyst bed, and the volume space velocity is controlled at 0.6 h -1 , and the hydrogen-oil volume ratio is 700:1, and it is operated at a constant temperature for 32 h. Then, for the second-stage passivation, it is adjusted so that the total injection mass of the passivation aid accounts for 20% of the mass of the passivation feedstock oil, the hydrofining catalyst bed is at 337 °C, the hydrocracking catalyst bed is at 347 °C, and other conditions remain unchanged, and it continues to be operated at a constant temperature for 24 h.

[0092] After the catalyst passivation is completed, the catalytic diesel oil is switched in batches (the composition is shown in Table 1), and the injection ratio of the passivation aid in each bed remains unchanged during the switching process. Based on the total weight of the passivation feedstock oil and the catalytic diesel oil, 25% of the catalytic diesel oil is switched in, and the total mass content of the passivation aid injection is reduced to 18%, and the temperature is kept constant for 10 h; the proportion of the catalytic diesel oil is increased to 50%, and the total mass content of the passivation aid injection is reduced to 16%, and the temperature is kept constant for 10 h; the proportion of the catalytic diesel oil is increased to 75%, and the total mass content of the passivation aid injection is reduced to 14%, and the temperature is kept constant for 10 h; the proportion of the catalytic diesel oil is increased to 100%, and the total mass content of the passivation aid injection is reduced to 12%, and the temperature is kept constant for 10 h. After all of this process is completed, the injection of the passivation aid is stopped, and the subsequent hydrofining reaction and hydrocracking reaction are carried out. The reaction conditions of the hydrofining reaction and the hydrocracking reaction are shown in Table 2. The results are shown in Table 2.

[0093] Example 2

[0094] A conventional trickle-bed hydrogenation reactor is selected. The reactor is filled with sulfided FHUDS-10 catalyst and FC-90 catalyst. Along the flow direction of the material, the hydrofining catalyst is loaded upstream of the hydrocracking catalyst, and the hydrofining catalyst and the hydrocracking catalyst are loaded into 6 series-connected catalyst beds in total, among which the number of catalyst beds loaded with the hydrofining catalyst is 2, and the number of catalyst beds loaded with the hydrocracking catalyst is 4. The loading volume ratio of the FHUDS-10 catalyst to the FC-90 catalyst is 3:7. The first-stage passivation is carried out. The passivation feedstock oil-1 and hydrogen in Table 1 enter the hydrogenation reactor and flow from the 1st catalyst bed to the 6th catalyst bed along the flow direction of the material. The total mass of the passivation aid (di-tert-butyl polysulfide) injection accounts for 15% of the mass of the passivation feedstock oil. The injection mass of the passivation aid in the first bed is 18% of the total mass of the passivation aid injection. The injection amounts of the passivation aid for the catalysts in the second bed, the third bed, the fourth bed, the fifth bed, and the sixth bed are each reduced by 3% by weight relative to the injection amount of the passivation aid in the previous bed, and are respectively injected at the inlet of each bed. The reaction temperature is adjusted to 340 °C in the loading area of the hydrofining catalyst and 350 °C in the loading area of the hydrocracking catalyst, and the volumetric space velocity is controlled at 0.6 h -1 , and the hydrogen-oil volume ratio is 700:1, and the constant temperature operation is carried out for 36 h. Then the second-stage passivation is carried out. It is adjusted to that the total mass of the passivation aid injection accounts for 30% of the mass of the passivation feedstock oil, 335 °C in the loading area of the hydrofining catalyst, 345 °C in the loading area of the hydrocracking catalyst, and other conditions remain unchanged, and the constant temperature operation is continued for 32 h.

[0095] After the catalyst passivation is completed, the catalytic diesel is switched in batches (the composition is shown in Table 1), and the injection ratio of the passivation aid in each bed remains unchanged during the switching process. Based on the total weight of the passivation feedstock oil and the catalytic diesel, 20% of the catalytic diesel is switched in, and the total mass content of the passivation aid injection is reduced to 27%, and the temperature is kept constant for 8 hours; the proportion of the catalytic diesel is increased to 40%, and the total mass content of the passivation aid injection is reduced to 24%, and the temperature is kept constant for 8 hours; the proportion of the catalytic diesel is increased to 60%, and the total mass content of the passivation aid injection is reduced to 21%, and the temperature is kept constant for 8 hours; the proportion of the catalytic diesel is increased to 80%, and the total mass content of the passivation aid injection is reduced to 18%, and the temperature is kept constant for 8 hours; the proportion of the catalytic diesel is increased to 100%, and the total mass content of the passivation aid injection is reduced to 15%, and the temperature is kept constant for 8 hours. After this process is completed, the injection of the passivation aid is stopped, and the subsequent hydrofining reaction and hydrocracking reaction are carried out. The reaction conditions of the hydrofining reaction and the hydrocracking reaction are shown in Table 2. The results are shown in Table 2.

[0096] Example 3

[0097] It is carried out according to the method of Example 1, except that the passivation aid is changed to tert-nonyl polysulfide.

[0098] The results are shown in Table 2.

[0099] Example 4

[0100] It is carried out according to the method of Example 1, except that the passivation feedstock oil is changed to the third normal paraffin oil, and the specific composition is shown in the passivation feedstock oil-2 in Table 1.

[0101] The results are shown in Table 2.

[0102] Example 5

[0103] It is carried out according to the method of Example 1, except that the injection mass of the passivation aid in the 5 catalyst beds is equal (i.e., the passivation aid is equally divided).

[0104] The results are shown in Table 2.

[0105] Example 6

[0106] It is carried out according to the method of Example 2, except that in the 6 beds, the injection mass of the passivation aid in the first bed is 15.5% of the total mass of the passivation aid injection, and the injection amounts of the passivation aid in the second bed, the third bed, the fourth bed, the fifth bed, and the sixth bed each increase by 3 wt% relative to the injection amount of the passivation aid in the previous bed.

[0107] The results are shown in Table 2.

[0108] Comparative Example 1

[0109] It is carried out according to the method of Example 1, except that a passivation aid (di-tert-butyl polysulfide) is not used. Specifically:

[0110] First-stage passivation: The passivation feedstock oil and hydrogen enter the reactor, and the reaction temperature is adjusted to 345 °C for the hydrofining catalyst bed and 355 °C for the hydrocracking catalyst bed. The volume hourly space velocity is controlled at 0.6 h -1 , and the hydrogen-oil volume ratio is 700:1, and it is operated at a constant temperature for 32 h.

[0111] Second-stage passivation: It is adjusted to 337 °C for the hydrofining catalyst bed and 347 °C for the hydrocracking catalyst bed, and other conditions remain unchanged, and it is continuously maintained at a constant temperature for 24 h.

[0112] After the catalyst passivation is completed, the catalytic diesel is switched in batches. Based on the total weight of the passivation feedstock oil and the catalytic diesel, 25% of the catalytic diesel is switched in and maintained at a constant temperature for 10 h; the proportion of the catalytic diesel is increased to 50% and maintained at a constant temperature for 10 h; the proportion of the catalytic diesel is increased to 75% and maintained at a constant temperature for 10 h; the proportion of the catalytic diesel is increased to 100% and maintained at a constant temperature for 10 h. After this process is all completed, the subsequent hydrofining reaction and hydrocracking reaction are carried out. The reaction conditions of the hydrofining reaction and the reaction conditions of the hydrocracking reaction are shown in Table 2. The results are shown in Table 2.

[0113] Table 1

[0114] Passivated feedstock oil - 1 Passivated feedstock oil - 2 Catalytic diesel <![CDATA[Density (20 °C), g / cm 3 > 0.8659 0.8512 0.9509 Distillation range / °C (ASTM D86) 215-385 205-369 189-405 Sulfur, μg / g 9800 8500 3235 Organic nitrogen, μg / g 115 96 421 Aromatic hydrocarbon content, wt% 28.5 26.5 69 Polycyclic aromatic hydrocarbon content, wt% / / 48

[0115] Table 2

[0116]

[0117]

[0118] It can be seen from the results in Table 2 that by using the method of the present invention, the carbon deposition rate of the catalyst can be effectively controlled, the passivation process of the catalyst can be strengthened, and the qualified period of the gasoline product can be greatly shortened.

[0119] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and all fall within the protection scope of the present invention.

Claims

1. A method for catalytic hydrocracking of catalytic diesel to produce high-octane gasoline, characterized in that, the method comprises the following steps: (1) Under the action of a passivation feedstock oil, hydrogen, and a passivation aid, a hydrofining catalyst and a hydrocracking catalyst are subjected to a passivation reaction to obtain a passivated hydrofining catalyst and a passivated hydrocracking catalyst. Among them, along the material flow direction, the hydrofining catalyst is loaded upstream of the hydrocracking catalyst, and the hydrofining catalyst and the hydrocracking catalyst are jointly loaded in n series-connected catalyst beds, and the passivation aid is respectively injected into the n series-connected catalyst beds, where n is a positive integer and n≥2; (2) After the passivation reaction is completed, the passivation feedstock oil is switched to catalytic diesel, and the injection amount of the passivation aid is reduced until it stops; (3) The mixed material containing catalytic diesel and the passivation aid and hydrogen are successively contacted with the passivated hydrofining catalyst and the passivated hydrocracking catalyst to respectively carry out a hydrofining reaction and a hydrocracking reaction to obtain gasoline.

2. The method according to claim 1, wherein, n is 2 - 15, preferably 4 - 10, and n is a positive integer; Preferably, the number of loading beds of the hydrofining catalyst is 1 - 6, preferably 2 - 4; Preferably, the number of loading beds of the hydrocracking catalyst is 2 - 8, preferably 2 - 6; Preferably, along the material flow direction, the injection mass of the passivation aid in the n catalyst beds is equal; Or, along the material flow direction, relative to the injection mass of the passivation aid in the previous bed, the injection amount of the passivation aid in the n catalyst beds gradually decreases, preferably decreasing by 3 - 20% by weight in sequence; Preferably, along the material flow direction, based on the total injection mass of the passivation aid, the injection amount of the passivation aid in the first catalyst bed is 15 - 35% by weight.

3. The method according to claim 1, wherein, Along the material flow direction, the passivation feedstock oil and hydrogen flow from the first catalyst bed to the nth catalyst bed; Preferably, both the hydrofining catalyst and the hydrocracking catalyst in step (1) are catalysts after sulfidation treatment.

4. The method according to any one of claims 1 - 3, wherein, The initial boiling point of the passivation feedstock oil is 155 - 330°C, preferably 170 - 250°C; the final boiling point is 350 - 420°C; Preferably, in the passivation feedstock oil, the aromatic hydrocarbon content is less than 35 wt%, preferably 15 - 32 wt%; Preferably, in the passivation feedstock oil, the organic nitrogen content is less than 250 μg / g, preferably 50 - 180 μg / g; Preferably, the passivation feedstock oil is a heavy diesel fraction, preferably selected from at least one of the second normal distillate oil, the third normal distillate oil, the fourth normal distillate oil, the reduced top oil, the first reduced oil, and straight-run diesel, and more preferably selected from at least one of the fourth normal distillate oil, the reduced top oil, and the first reduced oil.

5. The method according to any one of claims 1 - 4, wherein, The passivation aid is a sulfide, preferably selected from at least one of di-tert-butyl sulfide, di-tert-butyl disulfide, di-tert-butyl polysulfide, tert-nonyl polysulfide, tert-dodecyl polysulfide, diphenyl sulfide, diphenyl disulfide, diphenyl polysulfide, and di-tert-nonyl sulfide.

6. The method according to any one of claims 1-5, wherein, The conditions of the passivation reaction described in step (1) include: the temperature is 300 - 360 °C, preferably 315 - 355 °C; the space velocity is 0.2 - 6 h -1 , preferably 0.5 - 4 h -1 ; the hydrogen-oil volume ratio is 200 - 2000:1, preferably 500 - 1500:1; the passivation time is 36 - 108 h, preferably 40 - 80 h; preferably, the mass of the passivation aid is 0.5-30% of the mass of the passivated feedstock oil, preferably 5-30%.

7. The method according to claim 6, wherein, the passivation reaction in step (1) includes a first passivation reaction and a second passivation reaction; preferably, the temperature of the first passivation reaction is 3-30 °C higher than that of the second passivation reaction, preferably 3-10 °C higher; preferably, in the first passivation reaction, the mass of the passivation aid is 0.5-20% of the mass of the passivated feedstock oil, preferably 5-15%; preferably, the time of the first passivation reaction is 24-60 h, preferably 24-48 h; preferably, in the second passivation reaction, the mass of the passivation aid is 15-30% of the mass of the passivated feedstock oil, preferably 20-30%; preferably, the time of the second passivation reaction is 12-48 h, preferably 16-32 h.

8. The method according to any one of claims 1-7, wherein, in the mixed material, the mass of the passivation aid is 5-20% of the mass of the catalytic diesel.

9. The method according to any one of claims 1-8, wherein, the hydrofining catalyst includes a first carrier and a first metal component supported on the first carrier, wherein the first carrier contains a heat-resistant inorganic oxide, and the first metal component includes a Group VIB metal component and a Group VIII metal component; preferably, the heat-resistant inorganic oxide is selected from at least one of silica, alumina, amorphous silica-alumina, zirconia, and titania; preferably, based on the total weight of the first hydrocracking catalyst, in the first hydrocracking catalyst, calculated as oxides, the content of the first metal component is 15-50% by weight, preferably 18-45% by weight; preferably, based on the total weight of the first hydrocracking catalyst, in the first hydrocracking catalyst, calculated as oxides, the content of the Group VIII metal component is 1.5-8% by weight, preferably 2-6% by weight.

10. The method according to any one of claims 1-9, wherein, the hydrocracking catalyst includes a second carrier and a second metal component supported on the second carrier, wherein the second carrier contains Y-type molecular sieve, and the second metal component includes a Group VIB metal component and a Group VIII metal component; preferably, based on the total weight of the second hydrocracking catalyst, in the second hydrocracking catalyst, calculated as oxides, the content of the second metal component is 3-50% by weight, preferably 18-40% by weight; preferably, based on the total weight of the second hydrocracking catalyst, in the second hydrocracking catalyst, calculated as oxides, the content of the Group VIII metal component is 1.5-8% by weight, preferably 2-6% by weight.

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