Method for rapidly producing high-octane gasoline by catalytic diesel hydrocracking

Abstract

The present invention relates to the field of producing high-octane gasoline from catalytic diesel, and discloses a method for rapidly producing high-octane gasoline by hydrocracking of catalytic diesel. The method includes: respectively performing first passivation on a hydrofining catalyst and a hydrocracking catalyst under a passivation feedstock oil, hydrogen, and alkanes of C2-C6; respectively performing second passivation on the first-passivated hydrofining catalyst and the hydrocracking catalyst after the first passivation reaction under a passivation feedstock oil, hydrogen, alkanes of C2-C6, and a first passivation aid to obtain a passivated hydrofining catalyst and a passivated hydrocracking catalyst, wherein a second passivation aid is introduced during the second passivation reaction of the hydrocracking catalyst after the first passivation reaction; sequentially subjecting catalytic diesel and hydrogen to hydrofining and hydrocracking with the passivated hydrofining catalyst and the passivated hydrocracking catalyst. This method shortens the compliance period of the octane number of gasoline products in the initial stage of startup.

Description

Technical Field

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

[0002] With the increasing heaviness and inferiority of the feedstock processed by catalytic cracking units, the quality of the products of catalytic cracking, especially the quality of catalytic cracking light cycle oil (LCO), has further deteriorated. The LCO has a high sulfur content and aromatic content, and poor engine ignition performance. It is mainly used for blending fuel oil, non - vehicle diesel, heating oil, etc. abroad. In recent years, those skilled in the art have been thinking about how to efficiently convert the large amount of aromatics in LCO into high - value - added high - octane fuels. Currently, the most common method is to use a method of moderate cracking and shallow hydrogenation. This method can convert LCO into high - octane fuels, but there is a problem that the hydrogenation depth affects the loss of octane value during the hydroconversion of catalytic diesel.

[0003] Currently, in the domestic catalytic diesel hydroconversion units in operation, generally affected by the relatively high initial activity of the catalyst at the initial stage of unit startup, the catalyst system shows strong capabilities of hydrodesulfurization, denitrification, and dearomatization. At the same time, the hydrogenation performance of the hydrocracking catalyst is also relatively high, resulting in objective phenomena such as poor initial matching of hydrogenation activity and cracking activity. Specifically, at the initial stage of startup, the octane value of gasoline components is not high and cannot meet the production requirements. It takes a long time to stabilize before it can meet the requirements for producing high - grade octane gasoline.

[0004] US5114562 discloses a two - stage diesel hydrotreating process. In the first stage, a traditional hydrofining catalyst is used to remove impurities such as sulfur and nitrogen in the feedstock, and in the second stage, a catalyst with higher hydrogenation saturation activity is used for deep dearomatization. This method pays more attention to diesel quality improvement, does not consider the efficient utilization of rich aromatics, and at the same time has high hydrogen consumption, high investment, and poor economy.

[0005] CN109777714A discloses a method for catalytic diesel hydroconversion to produce high - octane gasoline. The used hydrocracking catalyst of Y - type molecular sieve has high ring - opening performance and high selectivity cracking performance for components rich in aromatics. It can effectively control the depth of aromatics hydrogenation saturation in the feedstock, convert and enrich some aromatics in the feedstock into the naphtha fraction to produce high - octane gasoline blending components. This method pays more attention to the development of the catalyst, but the strong - activity process at the initial stage cannot be avoided.

[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 in the initial stage of startup and extending the operation cycle of the unit is achieved. However, the synergistic effect between the hydrogenation and cracking reactions of the catalyst is not considered.

[0007] CN103865577A discloses a method for producing light aromatics and clean fuel oil products from catalytic cracking diesel. This method adopts a reverse hydrocracking-hydrofining process. After hydrofining, the catalytic diesel fraction oil is cut. The fraction oil with a temperature > 355 °C is mixed with hydrogen and then returned for hydrocracking; for the cut fraction oil, extraction is carried out. The raffinate oil rich in alkanes is used as a blending component for clean diesel; the extract oil rich in aromatics undergoes a hydrocracking reaction to produce light aromatics and a blending component for clean gasoline. This technology can produce clean gasoline and clean diesel simultaneously. However, for the middle-section feeding, it is easy to cause the temperature mismatch between the two catalyst beds, and the filling amount of the refining agent is small, resulting in a small processing capacity. All the extract oil rich in aromatics is used as the hydrocracking feedstock, which will increase the deactivation rate of hydrocracking and affect the operation cycle of the unit.

[0008] CN106753551A discloses a method for producing high-octane gasoline from catalytic cracking diesel in a large amount. After the catalytic diesel is hydrofined, it is cut into a fraction with a temperature < 280 °C and a fraction with a temperature > 280 °C. The raffinate oil obtained by the aromatics extraction of the fraction with a temperature > 280 °C and the fraction with a temperature < 280 °C are fed into the catalytic cracking unit together to produce high-octane gasoline, while the extract oil rich in aromatics is utilized for aromatics; a large amount of bicyclic and tricyclic aromatics in the HLCO of this method are not utilized and directly discharged from the unit, resulting in poor overall economic benefits and low yield.

[0009] 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, passing through two or more hydrocracking catalyst beds in sequence to carry out the hydrogenation conversion reaction; in the hydrofining reaction zone, along the direction of the material flow, 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 the active metals increases. This method 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 high catalyst activity in the initial stage of the unit startup is not considered, and the unit adjustment time cannot be shortened. Summary of the Invention

[0010] 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 rapidly produce gasoline with high octane number. This method can significantly shorten the compliance period of the octane number of gasoline products in the initial stage of startup.

[0011] To achieve the above object, on the one hand, the present invention provides a method for catalytic diesel hydrocracking to produce gasoline, which method comprises the following steps:

[0012] (1) Under the action of passivation feedstock oil, hydrogen, and alkanes of C2-C6, the hydrofining catalyst and the hydrocracking catalyst are respectively subjected to a first passivation reaction.

[0013] (2) Under the action of passivation feedstock oil, hydrogen, alkanes of C2-C6, and a first passivation aid, the hydrofining catalyst after the first passivation reaction and the hydrocracking catalyst after the first passivation reaction are respectively subjected to a second passivation reaction to obtain a passivated hydrofining catalyst and a passivated hydrocracking catalyst, wherein a second passivation aid is introduced during the process of the hydrocracking catalyst after the first passivation reaction undergoing the second passivation reaction.

[0014] (3) The catalytic diesel 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.

[0015] Wherein, the first passivation aid is an alkene and / or alkyne of C2-C5; the second passivation aid is a C8 + aromatic hydrocarbon.

[0016] Through the above technical solution, the beneficial effects of the present invention include:

[0017] The present invention adopts the existing catalytic diesel hydroconversion process. By strengthening the passivation process of the hydrofining catalyst and the hydrocracking catalyst in the initial operation stage, optimizing the passivation medium (selecting passivation feedstock oil, alkanes of C2-C6, the first passivation aid, and the second passivation aid), especially introducing the first passivation aid and / or the second passivation aid in the second stage of catalyst passivation, it is possible to synchronously adjust the carbon deposition rate of the hydrofining catalyst and the hydrocracking catalyst system and form a progressive strengthening passivation effect. By strengthening the initial passivation process, fully matching the activity, controlling the carbon deposition rate of the catalyst, the present invention realizes shortening the period for the octane number of the produced gasoline product to meet the octane number requirement of national standard gasoline No. 92. And this method has few changes in operation steps, simple process, convenient operation, and good safety. Specific embodiments

[0018] The endpoints and any values disclosed in this text for a range are not limited to the exact range or value. These ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range, between the endpoint value of each range and a single point value, and between single point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed in this text.

[0019] In one aspect, the present invention provides a method for catalytic hydrocracking of catalytic diesel to produce gasoline. The method comprises the following steps:

[0020] (1) Under the action of a passivation feedstock oil, hydrogen, and alkanes having 2 to 6 carbon atoms, a first passivation reaction is respectively carried out on a hydrofining catalyst and a hydrocracking catalyst;

[0021] (2) Under the action of a passivation feedstock oil, hydrogen, alkanes having 2 to 6 carbon atoms, and a first passivation aid, a second passivation reaction is respectively carried out on the hydrofining catalyst after the first passivation reaction and the hydrocracking catalyst after the first passivation reaction to obtain a passivated hydrofining catalyst and a passivated hydrocracking catalyst. Among them, a second passivation aid is introduced during the process of carrying out the second passivation reaction on the hydrocracking catalyst after the first passivation reaction;

[0022] (3) The catalytic diesel 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;

[0023] Among them, the first passivation aid is an alkene and / or alkyne having 2 to 5 carbon atoms; the second passivation aid is a C8 + aromatic hydrocarbon.

[0024] In the method provided by the present invention, alkanes having 2 to 6 carbon atoms are introduced as a modulating initial carbon deposition medium at the beginning of the first stage of catalyst passivation, achieving the effect of initially changing the hydrogen partial pressure of the reaction system, realizing partial carbon deposition of the catalyst, avoiding excessive carbon deposition of the catalyst, realizing the matching of the hydrogenation activity and cracking performance of the catalyst system, and also avoiding the situation that the operating pressure of the recycle hydrogen compressor is too low and the compressor cannot work; then a first passivation aid and / or a second passivation aid are introduced in the second stage of catalyst passivation, which can realize synchronous modulation of the carbon deposition rate of the hydrofining catalyst and the hydrocracking catalyst system, and form a progressive strengthening passivation effect. The alkanes having 2 to 6 carbon atoms, the first passivation aid, and the second passivation aid added in the present invention are easily soluble in the passivation feedstock oil after reaction and can be smoothly discharged from the recycle hydrogen system, realizing controllable operation, avoiding excessive enrichment of low-carbon hydrocarbons in the recycle hydrogen, and can be quickly switched to the normal production condition without affecting the operation of the unit and the quality of other products.

[0025] In the present invention, the first passivation reactions of the two types of catalysts, namely the hydrofining catalyst and the hydrocracking catalyst, can be carried out simultaneously or in a sequential order (generally, the first passivation of the hydrofining catalyst is carried out first, and then the first passivation of the hydrocracking catalyst), and both can be achieved by adopting conventional methods in the art. The present invention has no special requirements in this regard. The same applies to the second passivation reactions of the hydrofining catalyst and the hydrocracking catalyst.

[0026] In the present invention, the hydrofining catalyst and the hydrocracking catalyst can be filled in two serially connected passivation reactors respectively, or can be filled in one passivation reactor. In order 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 filled in one passivation reactor.

[0027] The present invention has no particular limitation on the type selection of the passivation reactor, and various passivation reactors that can implement 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, and more 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 standard at the initial stage of startup, reduce investment, save costs, and improve economic efficiency.

[0028] The present invention has no particular limitation on the filling ratio of the hydrofining catalyst and the hydrocracking catalyst in the passivation process, and it can be appropriately selected according to the subsequent hydrogenation reaction requirements, and can be selected with reference to conventional methods in the art. Generally, the amount of initial passivation in the front is the same as the amount required for the subsequent reaction. Preferably, the filling volume ratio of the hydrofining catalyst to the hydrocracking catalyst is 7:3 - 3:7, and preferably 6:4 - 4:6.

[0029] According to the present invention, preferably, both the hydrofining catalyst and the hydrocracking catalyst in step (1) are catalysts after sulfidation treatment.

[0030] The present invention has no particular limitation on the method of the sulfidation treatment, which can be the pre-sulfidation method commonly used in the art or the true / total sulfidation method commonly used in the art. The present invention does not make special limitations in this regard.

[0031] According to the present invention, preferably, the conditions of the first passivation reaction and the second passivation reaction each independently include: the temperature is 310 - 400 °C, preferably 320 - 370 °C; the volume space velocity is 0.5 - 7 h -1 , preferably 0.5 - 4 h -1; The hydrogen-oil volume ratio is 300 - 2000:1, preferably 600 - 1500:1; the total pressure is 2.5 - 20 MPa, preferably 6 - 15 MPa. Adopting this preferred embodiment is more conducive to the catalyst to achieve the activity matching of the hydrofining catalyst and the hydroconversion catalyst according to the actual reaction situation in the reaction zone.

[0032] 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 (hydrofining catalyst and hydrocracking catalyst) in the entire reactor.

[0033] In the present invention, the conditions of the first passivation reaction and the second passivation reaction can be the same or different. Preferably, the space velocity and the hydrogen-oil volume ratio of the first passivation reaction and the second passivation reaction are the same.

[0034] According to the present invention, preferably, in the first passivation reaction, the volume of C2 - C6 alkanes introduced accounts for 5 - 35% of the total volume of hydrogen and C2 - C6 alkanes, preferably 10 - 30%, for example, it can be 5%, 10%, 15%, 20%, 25%, 30%, 35% and the range values formed by any two of these point values.

[0035] According to the present invention, preferably, the time of the first passivation reaction is 20 - 72 h, preferably 24 - 50 h.

[0036] According to the present invention, preferably, in the second passivation reaction, the volume of C2 - C6 alkanes introduced accounts for 5 - 35% of the total volume of hydrogen and C2 - C6 alkanes, preferably 5 - 25%, for example, it can be 5%, 10%, 15%, 20%, 25%, 30%, 35% and the range values formed by any two of these point values.

[0037] According to the present invention, preferably, in the second passivation reaction, the added mass of the first passivation aid is 2 - 20% of the mass of the passivation feedstock oil, preferably 10 - 20%, for example, it can be 2%, 4%, 6%, 8%, 10%, 12%, 14%, 16%, 18%, 20% and the range values formed by any two of these point values.

[0038] According to the present invention, preferably, in the second passivation reaction, the added mass of the second passivation aid is 1 - 15% of the mass of the passivation feedstock oil, preferably 1 - 10%, for example, it can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15% and the range values formed by any two of these point values.

[0039] According to the present invention, preferably, the time of the second passivation reaction is 6 - 60 h, preferably 6 - 48 h.

[0040] According to the present invention, preferably, the C2-C6 alkane is selected from at least one of ethane, propane, n-butane, isobutane, n-pentane, isopentane, neopentane, cyclopentane, n-hexane, cyclohexane, methylcyclopentane, 2-methylpentane, 3-methylpentane, 2,2-methylbutane, and 2,3-dimethylbutane, and preferably selected from at least one of propane, n-butane, isobutane, n-pentane, and isopentane. By using the above specific types of C2-C6 alkanes, which are in the gas phase under certain conditions, the reaction environment in the reaction zone is regulated, the moderate carbon deposition of the highly active catalyst is promoted, the goal of activity regulation is achieved, and it can be better dissolved in the passivation feedstock oil in a low-temperature environment, which is more conducive to the stepwise carbon deposition of the catalyst and better achieves the purpose of adjusting the initial activity of the catalyst, ensuring the matching of the hydrogenation and conversion performance of the catalyst.

[0041] According to the present invention, preferably, the first passivation aid is selected from at least one of ethylene, propylene, butene, pentene, acetylene, propyne, and butyne. By using the above specific types of first passivation aids, which have high chemical activity and are easily reacted with the active components on the catalyst surface to form carbon deposition or coking substances, it is more conducive to strengthening the stepwise carbon deposition in the catalyst passivation process and achieving the goal of moderate carbon deposition of the catalyst, further ensuring the matching of the hydrogenation and conversion performance of the catalyst.

[0042] According to the present invention, preferably, the second passivation aid is a benzene-based compound and / or a naphthalene-based compound, preferably containing at least one of an alkenyl group, an alkynyl group, an alkyl group, and a carboxyl group.

[0043] More preferably, the second passivation aid is selected from at least one of styrene, methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, phenylpropylene, 1-methylnaphthalene, 2-methylnaphthalene, 1-allylnaphthalene, 1-naphthoic acid, 1-vinylnaphthalene, and 2-vinylnaphthalene. By using the above specific types of second passivation aids, through the control of the carbon deposition precursor (the reaction product of the second passivation aid), the stepwise carbon deposition in the hydrogenation cracking catalyst passivation process is further strengthened to achieve the goal of moderate carbon deposition, further ensuring the matching of the hydrogenation and conversion performance of the catalyst and reducing the loss of gasoline octane number.

[0044] According to the present invention, preferably, the initial boiling point of the passivation feedstock oil is 150-300 °C, preferably 150-250 °C; the final boiling point is 320-450 °C, preferably 370-420 °C.

[0045] According to the present invention, preferably, the density of the passivation feedstock oil is 0.84-0.89 g / cm 3 .

[0046] According to the present invention, preferably, the sulfur content of the passivation feedstock oil is not less than 6000 mg / g, preferably 9000 - 15000 mg / g.

[0047] According to the present invention, preferably, in the passivation feedstock oil, the organic nitrogen content is not less than 50 μg / g, preferably 80 - 200 μg / g.

[0048] Using the passivation feedstock oil with the above characteristics is more conducive to realizing the initial activity modulation of the catalyst.

[0049] 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 distillate, 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 distillate. Adopting this preferred embodiment is more conducive to making full use of the characteristics of the passivation feedstock oil with a higher proportion of heavier components but fewer coke-forming substances, giving full play to the activity of the catalyst, and achieving the effect of moderately regulating the activity of the catalyst.

[0050] In the present invention, after the passivation is completed, the passivation feedstock oil needs to be switched to catalytic diesel. For the safety and controllability of the initial passivation process, including further controlling the impact of the raw material deterioration on the catalyst coking process after processing catalytic diesel. Preferably, the method further includes: after the second passivation reaction is completed, the passivation feedstock oil is switched to the catalytic diesel described in step (3) in batches, and during this process, the injection amounts of C2 - C6 alkanes, the first passivation aid, and the second passivation aid are reduced in batches.

[0051] Preferably, based on the total weight of the passivation feedstock oil and the catalytic diesel, the increase ratio of the catalytic diesel in each switch is 10 - 35 wt%.

[0052] It should be noted that the above increase ratio is the difference between the percentage of the catalytic diesel in the current switch and the percentage of the catalytic diesel in the previous switch. The percentage refers to the mass content of the catalytic diesel based on the total weight of the passivation feedstock oil and the catalytic diesel.

[0053] For example: based on the total weight of the passivation feedstock oil and the catalytic diesel, when the second switch is made, the injection amount of the catalytic diesel is 20%, and when the first switch is made, the injection amount of the catalytic diesel is 15%, and the increase ratio is 5%.

[0054] Preferably, based on the total volume of hydrogen and C2 - C6 alkanes, the reduction ratio of C2 - C6 alkanes in each switch is 0.5 - 5 vol%.

[0055] It should be noted that the above reduction ratio is the difference between the injection percentage of C2-C6 alkanes in the previous switch and that in the current switch. The percentage refers to the percentage of the injection volume of C2-C6 alkanes in the total volume of hydrogen and C2-C6 alkanes.

[0056] For example: based on the total volume of hydrogen and C2-C6 alkanes, the injection amount of C2-C6 alkanes at the second switch is 5%, and the injection amount of C2-C6 alkanes at the first switch is 6%, and the reduction ratio is 1%.

[0057] Preferably, based on the total weight of the passivation feedstock oil and catalytic diesel, the reduction ratio of the total amount of the first passivation aid and the second passivation aid in each switch is 1-17.5% by weight.

[0058] It should be noted that the above reduction ratio is the difference between the percentage of the total injection amount of the first and second passivation aids in the previous switch and that in the current switch. The percentage refers to the percentage of the total injection amount of the first and second passivation aids in 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 total injection amount of the first and second passivation aids at the second switch is 20%, and the total injection amount of the first and second passivation aids at the first switch is 25%, and the reduction ratio is 5%.

[0060] In the present invention, for the total amount of the first passivation aid and the second passivation aid, the reduction ratio can be equal or unequal in each switch, as long as the total mass of the first passivation aid and the second passivation aid in the subsequent obtained mixed material satisfies the following conditions.

[0061] The present invention does not particularly limit the reduction situation of each of the first passivation aid and the second passivation aid during each switch, as long as the mass ratio of the first passivation aid to the second passivation aid in the subsequent obtained mixed material satisfies the following conditions.

[0062] Preferably, the time interval between two adjacent switches of catalytic diesel is 4-15 h.

[0063] The present invention does not particularly limit the number of switches, and it is based on reaching 100% switch to catalytic diesel.

[0064] According to the present invention, further preferably, when the passivation feedstock oil is switched to 100% catalytic diesel, the injection of C2-C6 alkanes and the first passivation aid is stopped. By adopting this preferred implementation mode, the second passivation aid is continuously injected, and its reaction by-products are beneficial to the improvement of the octane number.

[0065] It is understandable that after the passivation feedstock oil is switched to 100% catalytic diesel, the injection of C2-C6 alkanes and the first passivation aid stops, while the second passivation aid continues to be injected.

[0066] According to the present invention, preferably, the process of step (3) includes: in the presence of hydrogen, successively contacting the mixed material containing catalytic diesel, C2-C6 alkanes, the first passivation aid, and the second passivation aid with a passivation hydrofining catalyst and a passivation hydrocracking catalyst to respectively carry out hydrofining reaction and hydrocracking reaction to obtain gasoline.

[0067] It is understandable that in the mixed material in step (3), the catalytic diesel and the second passivation aid are continuously introduced, and the C2-C6 alkanes and the first passivation aid remain in the system after the switching is completed.

[0068] When switching to 100% catalytic diesel, it is necessary to control the content of C2-C6 alkanes at the following specific level, which is beneficial to further adjusting the initial activity of the catalyst, avoiding too high initial catalyst activity, excessive saturation and cracking, and achieving the goal of quickly adjusting the match between the catalyst activity and the processing feedstock. Preferably, in the mixed material, the volume of C2-C6 alkanes is 1-15% of the total volume of hydrogen and C2-C6 alkanes, for example, it can be 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, and any value within the range formed by any two of these point values.

[0069] According to the present invention, preferably, in the mixed material, the total mass of the first passivation aid and the second passivation aid is 2-20% of the mass of the catalytic diesel, for example, it can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16%, 17%, 18%, 19%, 20%, and any value within the range formed by any two of these point values.

[0070] Preferably, in the mixed material, the mass ratio of the second passivation aid to the first passivation aid is 1:0.5-4, for example, it can be 1:0.5, 1:0.6, 1:0.7, 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, 1:1.5, 1:1.8, 1:2, 1:2.1, 1:2.2, 1:2.5, 1:2.8, 1:3, 1:3.1, 1:

[0071] 3.2, 1:3.5, 1:3.8, 1:4, and any value within the range formed by any two of these point values, preferably 1:1-4.

[0072] It is understood that the volume of C2-C6 alkanes, the total mass of the first passivation aid and the second passivation aid, and the mass ratio of the second passivation aid to the first passivation aid in the mixed material refer to: the volume of C2-C6 alkanes, the total mass of the first passivation aid and the second passivation aid, and the mass ratio of the second passivation aid to the first passivation aid under the condition of switching to 100% catalytic diesel.

[0073] The present invention does not particularly limit the type of the hydrofining catalyst, and it 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.

[0074] 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.

[0075] 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.

[0076] 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 Group VIII metal component is 1.5-8% by weight, preferably 2-6% by weight.

[0077] According to the present invention, preferably, the Group VIB metal component is Mo and / or W.

[0078] According to the present invention, preferably, the Group VIII metal component is Ni and / or Co.

[0079] 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 a conventional method.

[0080] The present invention does not particularly limit the type of the hydrocracking catalyst, and it 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 a Y-type molecular sieve, and the second metal component includes a Group VIB metal component and a Group VIII metal component.

[0081] 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.

[0082] According to the present invention, preferably, based on the total weight of the hydrocracking catalyst, in the hydrocracking catalyst, the content of the second metal component is 3-50% by weight, preferably 18-40% by weight in terms of oxide.

[0083] According to the present invention, preferably, based on the total weight of the hydrocracking catalyst, in the hydrocracking catalyst, the content of the Group VIII metal component is 1.5-8% by weight, preferably 2-6% by weight in terms of oxide.

[0084] According to the present invention, preferably, the Group VIB metal component is Mo and / or W.

[0085] According to the present invention, preferably, the Group VIII metal component is Ni and / or Co.

[0086] There is no particular limitation on the source of the hydrocracking catalyst of the present invention, and it can be obtained through commercial purchase or prepared by conventional methods.

[0087] 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.

[0088] Preferably, in the catalytic diesel, the aromatic hydrocarbon content is ≥45 wt%, preferably 50-75 wt%.

[0089] Further preferably, in the catalytic diesel, the polycyclic aromatic hydrocarbon content is ≥35 wt%, preferably 40-60 wt%.

[0090] 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.

[0091] 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.

[0092] 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.

[0093] The product meeting the octane number requirements of national standard gasoline No. 92 can be obtained by using the method of the present invention. Preferably, the sulfur content of the gasoline product is ≤ 10 μg / g, and the research octane number is ≥ 92.

[0094] In the present invention, the "first" and "second" do not play a limiting role in each substance and operation, but are only used to distinguish the substances introduced in different steps and the operations carried out in different stages.

[0095] The present invention will be described in detail below through examples.

[0096] In the following examples, the hydrofining catalyst used is the FHUDS-10 catalyst produced by Sinopec Catalyst Co., Ltd., Dalian Co., Ltd.; the hydrocracking catalyst is the FC-24 catalyst produced by Fushun Branch of Sinopec Catalyst Company. Among them, the FHUDS-10 catalyst uses alumina as the carrier and Mo-Ni as the active components; the FC-24 catalyst uses modified Y-type molecular sieve as the carrier and W-Ni as the active metal components.

[0097] Example 1

[0098] A conventional trickle-bed hydrogenation reactor is selected. The reactor is filled with the sulfided FHUDS-10 catalyst and FC-24 catalyst, and the filling volume ratio of the FHUDS-10 catalyst to the FC-24 catalyst is 4:6. For the first-stage passivation, the passivation feedstock oil - 1 (normal third-line diesel), hydrogen, and C2 - C6 alkanes (ethane) in Table 1 enter the reactor from the inlet of the hydrofining catalyst bed layer, and the injection volume of ethane accounts for 12% of the total volume of ethane and hydrogen. The reaction temperature is adjusted to 347 °C for the hydrofining catalyst bed layer and 352 °C for the hydrocracking catalyst bed layer, and the volume space velocity is controlled at 0.7 h -1 , the hydrogen-oil volume ratio is 800:1, the total pressure is 12 MPa, and it is kept at a constant temperature for 30 h to obtain the hydrofining catalyst after the first-stage passivation and the hydrocracking catalyst after the first-stage passivation. For the second-stage passivation, the passivation feedstock oil, hydrogen, ethane, and the first passivation assistant (propylene) introduced from the inlet of the hydrofining catalyst bed layer are successively contacted with the hydrofining catalyst after the first-stage passivation and the hydrocracking catalyst after the first-stage passivation, and the second passivation assistant (styrene propylene) is introduced from the inlet of the hydrocracking catalyst bed layer. Among them, the injection mass of propylene accounts for 18% of the mass of the passivation feedstock oil, and the injection mass of styrene propylene accounts for 9% of the mass of the passivation feedstock oil. Other conditions are the same as those in the first-stage passivation, and it is kept at a constant temperature for 16 h.

[0099] After the catalyst passivation reaction is completed, catalytic diesel (composition shown in Table 1) is switched in batches. Based on the total weight of the passivation feedstock oil and catalytic diesel, 20% of catalytic diesel is switched in, and the injection of the first passivation aid and the second passivation aid is reduced to 24% of the total weight of the passivation feedstock oil and catalytic diesel, the volume ratio of ethane in its mixture with hydrogen is reduced by 1%, and the temperature is kept constant for 8 h; then the proportion of catalytic diesel is increased to 40%, and the injection of the first passivation aid and the second passivation aid is reduced to 21% of the total weight of the passivation feedstock oil and catalytic diesel, the volume ratio of ethane in its mixture with hydrogen is reduced by 1% compared with the previous switch, and the temperature is kept constant for 8 h; then the proportion of catalytic diesel is increased to 60%, and the injection of the first passivation aid and the second passivation aid is reduced to 18% of the total weight of the passivation feedstock oil and catalytic diesel, the volume ratio of ethane in its mixture with hydrogen is reduced by 1% compared with the previous switch, and the temperature is kept constant for 8 h; then the proportion of catalytic diesel is increased to 80%, the injection of the first passivation aid and the second passivation aid is reduced to 15% of the total weight of the passivation feedstock oil and catalytic diesel, the volume ratio of ethane in its mixture with hydrogen is reduced by 1% compared with the previous switch, and the temperature is kept constant for 8 h; finally, the proportion of catalytic diesel is increased to 100%, the injection of the first passivation aid and the second passivation aid is reduced to 12% of the total weight of the passivation feedstock oil and catalytic diesel (the mass ratio of the second passivation aid to the first passivation aid is 1:2), the volume ratio of ethane in its mixture with hydrogen is reduced by 1% compared with the previous switch, and the temperature is kept constant for 8 h. After this process is completed, the injection of ethane and the first passivation aid is stopped, the second passivation aid is continuously injected, and 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.

[0100] Example 2

[0101] A conventional trickle-bed hydrofining reactor is selected, and the reactor is filled with sulfided FHUDS-10 catalyst and FC-24 catalyst. The filling volume ratio of FHUDS-10 catalyst to FC-24 catalyst is 5:5. For the first-stage passivation, the passivation feedstock oil-1 (straight-run diesel from the third side stream), hydrogen, and C2-C6 alkanes (ethane) in Table 1 enter the reactor from the inlet of the hydrofining catalyst bed layer, and the injection volume of ethane accounts for 16% of the total volume of ethane and hydrogen. The reaction temperature is adjusted to 345 °C for the hydrofining catalyst bed layer and 347 °C for the hydrocracking catalyst bed layer, and the volume space velocity is controlled at 0.8 h -1, the hydrogen-oil volume ratio is 900:1, the total pressure is 12 MPa, and it operates at a constant temperature for 36 h to obtain the hydrofining catalyst after the first passivation reaction and the hydrocracking catalyst after the first passivation reaction. Then, the second passivation is carried out. The passivation feedstock oil, hydrogen, and ethane introduced from the inlet of the hydrofining catalyst are successively contacted with the hydrofining catalyst after the first passivation reaction and the hydrocracking catalyst after the first passivation reaction, and a second passivation aid (styrene propylene) is introduced from the inlet of the hydrocracking catalyst bed. Among them, the injection mass of propylene accounts for 10% of the mass of the passivation feedstock oil, the injection mass of styrene propylene accounts for 10% of the mass of the passivation feedstock oil, and other conditions are the same as those in the first passivation, and it is kept at a constant temperature for 20 h.

[0102] After the catalyst passivation is completed, the catalytic diesel is switched in batches (the composition is shown in Table 1). Based on the total weight of the passivation feedstock oil and the catalytic diesel, 25% of the catalytic diesel is switched in, and the injection of the first passivation aid and the second passivation aid is reduced to 18% of the total weight of the passivation feedstock oil and the catalytic diesel, and the volume ratio of ethane in its mixture with hydrogen is reduced by 2%, and it is kept at a constant temperature for 10 h; then the proportion of the catalytic diesel is increased to 50%, and the injection of the first passivation aid and the second passivation aid is reduced to 16% of the total weight of the passivation feedstock oil and the catalytic diesel, and the volume ratio of ethane in its mixture with hydrogen is reduced by 2% compared with the previous switch, and it is kept at a constant temperature for 10 h; then the proportion of the catalytic diesel is increased to 75%, and the injection of the first passivation aid and the second passivation aid is reduced to 14% of the total weight of the passivation feedstock oil and the catalytic diesel, and the volume ratio of ethane in its mixture with hydrogen is reduced by 2% compared with the previous switch, and it is kept at a constant temperature for 10 h; finally, the proportion of the catalytic diesel is increased to 100%, and the injection of the first passivation aid and the second passivation aid is reduced to 12% of the total weight of the passivation feedstock oil and the catalytic diesel (the mass ratio of the second passivation aid to the first passivation aid is 1:1), and the volume ratio of ethane in its mixture with hydrogen is reduced by 2%, and it is kept at a constant temperature for 10 h. After this process is all completed, the injection of ethane and the first passivation aid is stopped, and the second passivation aid is continuously injected, and the hydrofining reaction and the 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.

[0103] Example 3

[0104] It is carried out according to the method of Example 1, except that the first passivation aid is changed to butene.

[0105] The results are shown in Table 2.

[0106] Example 4

[0107] It is carried out according to the method of Example 1, except that the second passivation aid is changed to 2-vinylnaphthalene.

[0108] The results are shown in Table 2.

[0109] Example 5

[0110] It was carried out according to the method of Example 1, except that the passivation feedstock oil was changed to the first reduced crude oil, and the specific composition is shown in Passivation Feedstock Oil - 2 in Table 1.

[0111] The results are shown in Table 2.

[0112] Comparative Example 1

[0113] It was carried out according to the method of Example 2, except that C2 - C6 alkanes (ethane), the first passivation aid (ethylene), and the second passivation aid (styrene propylene) were not used. Specifically:

[0114] The first - stage passivation: The passivation feedstock oil and hydrogen entered the reactor. The reaction temperature was adjusted to 345 °C for the hydrofining catalyst bed and 347 °C for the hydrocracking catalyst bed, and the volume space velocity was controlled at 0.7 h -1 , and the hydrogen - to - oil volume ratio was 800:1, and it was kept at a constant temperature for 36 h.

[0115] After the catalyst passivation was completed, catalytic diesel was switched in batches. Based on the total weight of the passivation feedstock oil and catalytic diesel, 25% catalytic diesel was switched in and kept at a constant temperature for 10 h; then the proportion of catalytic diesel was increased to 50% and kept at a constant temperature for 10 h; then the proportion of catalytic diesel was increased to 75% and kept at a constant temperature for 10 h; finally, the proportion of catalytic diesel was increased to 100% and kept at a constant temperature for 10 h. After this process was all completed, the hydrofining reaction and the hydrocracking reaction were 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.

[0116] Table 1

[0117] Passivated feedstock oil - 1 Passivated feedstock oil - 2 Catalytic diesel <![CDATA[Density (20 °C), g / cm 3 > 0.8501 0.8715 0.9495 Distillation range / °C (ASTM D86) 195-367 209-377 206-389 Sulfur, μg / g 7955 11105 4595 Organic nitrogen, μg / g 85 125 467 Aromatic content, wt% 25 27.5 65 Polycyclic aromatic content, wt% / / 50

[0118] Table 2

[0119]

[0120] Note: The qualified adjustment duration is the period when the octane number of the gasoline product meets the requirements of the national standard gasoline with a grade of 92.

[0121] It can be seen from the results in Table 2 that by using the method of the present invention and optimizing the passivation medium (selecting the passivation feedstock oil, C2 - C6 alkanes, the first passivation aid, and the second passivation aid), the carbon deposition rate of the hydrofining catalyst and the hydrocracking catalyst synchronous modulation system can be achieved, forming a progressive enhanced passivation effect. Ensure that the hydrofining catalyst and the hydrocracking catalyst are fully matched in activity, control the carbon deposition rate of the catalyst, and realize shortening the period when the octane number of the produced gasoline product meets the requirements of the national standard gasoline with a grade of 92.

[0122] 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 solution 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 fall within the protection scope of the present invention.

Claims

1. A method for producing gasoline by catalytic hydrocracking of catalytic diesel, characterized in that, The method comprises the following steps: (1) Under the action of a passivation feedstock oil, hydrogen, and C2-C6 alkanes, a first passivation reaction is respectively carried out on a hydrofining catalyst and a hydrocracking catalyst; (2) Under the action of a passivation feedstock oil, hydrogen, C2-C6 alkanes, and a first passivation aid, a second passivation reaction is respectively carried out on the hydrofining catalyst after the first passivation reaction and the hydrocracking catalyst after the first passivation reaction to obtain a passivated hydrofining catalyst and a passivated hydrocracking catalyst. Among them, a second passivation aid is introduced during the second passivation reaction of the hydrocracking catalyst after the first passivation reaction; (3) The catalytic diesel 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; Among them, the first passivation aid is an olefin and / or alkyne having 2 to 5 carbon atoms; the second passivation aid is a C8 + aromatic hydrocarbon; Among them, the method further comprises: after the second passivation reaction is completed, the passivation feedstock oil is switched to the catalytic diesel described in step (3) in batches. During this process, the injection amounts of C2-C6 alkanes, the first passivation aid, and the second passivation aid are reduced in batches; When the passivation feedstock oil is switched to 100% catalytic diesel, the injection of C2-C6 alkanes and the first passivation aid is stopped; Among them, the process of step (3) includes: in the presence of hydrogen, a mixed material containing catalytic diesel, C2-C6 alkanes, the first passivation aid, and the second passivation aid is 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; Among them, the passivation feedstock oil is 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 distillate, and straight-run diesel; 2. The method according to claim 1, wherein The conditions of the first passivation reaction and the second passivation reaction each independently include: The temperature is 310 - 400 °C; the space velocity on volume basis is 0.5 - 7 h -1 ; the volume ratio of hydrogen to oil is 300 - 2000:1; the total pressure is 2.5 - 20 MPa.

3. The method according to claim 2, wherein The conditions for the first passivation reaction and the second passivation reaction each independently include: the temperature is 320 - 370 °C; the volume hourly space velocity is 0.5 - 4 h -1 ; the hydrogen-oil volume ratio is 600 - 1500:1; the total pressure is 6 - 15 MPa.

4. The method according to claim 1, wherein In the first passivation reaction, the introduced volume of C2-C6 alkanes accounts for 5-35% of the total volume of hydrogen and C2-C6 alkanes; The time of the first passivation reaction is 20-72 h.

5. The method according to claim 4, wherein In the first passivation reaction, the introduced volume of C2-C6 alkanes accounts for 10-30% of the total volume of hydrogen and C2-C6 alkanes; The time of the first passivation reaction is 24-50 h.

6. The method according to claim 1, wherein In the second passivation reaction, the introduced volume of C2-C6 alkanes accounts for 5-35% of the total volume of hydrogen and C2-C6 alkanes; In the second passivation reaction, the added mass of the first passivation aid is 2-20% of the mass of the passivation feedstock oil; In the second passivation reaction, the added mass of the second passivation aid is 1-15% of the mass of the passivation feedstock oil; The time of the second passivation reaction is 6-60 h.

7. The method according to claim 6, wherein In the second passivation reaction, the introduced volume of C2-C6 alkanes accounts for 5-25% of the total volume of hydrogen and C2-C6 alkanes; In the second passivation reaction, the added mass of the first passivation aid is 10-20% of the mass of the passivation feedstock oil; In the second passivation reaction, the added mass of the second passivation aid is 1-10% of the mass of the passivation feedstock oil; The time of the second passivation reaction is 6-48 h.

8. According to the method according to any one of claims 1-7, wherein, The C2-C6 alkane is selected from at least one of ethane, propane, n-butane, isobutane, n-pentane, isopentane, neopentane, n-hexane, 2-methylpentane, 3-methylpentane, 2,2-methylbutane, and 2,3-dimethylbutane.

9. According to the method according to claim 8, wherein, The C2-C6 alkane is selected from at least one of propane, n-butane, isobutane, n-pentane, and isopentane.

10. According to the method according to any one of claims 1-7, wherein, The first passivation aid is selected from at least one of ethylene, propylene, butene, pentene, acetylene, propyne, and butyne.

11. According to the method according to any one of claims 1-7, wherein, The second passivation aid is selected from at least one of styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, phenylpropylene, 1-methylnaphthalene, 2-methylnaphthalene, 1-allylnaphthalene, 1-naphthaleneacetic acid, 1-vinylnaphthalene, and 2-vinylnaphthalene.

12. According to the method according to any one of claims 1-7, wherein, The initial boiling point of the passivation feedstock oil is 150-300 °C; the final boiling point is 320-450 °C; The density of the passivated feedstock oil is 0.84 - 0.89 g / cm 3 ; The sulfur content of the passivation feedstock oil is not less than 6000 mg / g; In the passivation feedstock oil, the organic nitrogen content is not less than .

13. According to the method according to claim 12, wherein, The initial boiling point of the passivation feedstock oil is 150-250 °C; the final boiling point is 370-420 °C; The sulfur content of the passivation feedstock oil is 9000-15000 mg / g; In the passivation feedstock oil, the organic nitrogen content is .

14. According to the method according to any one of claims 1-7, wherein, The passivation feedstock oil is selected from at least one of the fourth normal paraffin oil, the topped vacuum oil, and the first reduced crude oil.

15. According to the method according to any one of claims 1-7, wherein, In the mixed material, the volume of the C2-C6 alkane accounts for 1-15% of the total volume of hydrogen and the C2-C6 alkane; In the mixed material, the total mass of the first passivation aid and the second passivation aid is 2-20% of the mass of the catalytic diesel oil; In the mixed material, the mass ratio of the second passivation aid to the first passivation aid is 1:0.5-4.

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