CN108102702B

CN108102702B - Method for processing catalytic diesel oil

Info

Publication number: CN108102702B
Application number: CN201611045475.8A
Authority: CN
Inventors: 王仲义; 彭冲; 崔哲; 刘昶; 吴子明; 孙士可
Original assignee: China Petroleum and Chemical Corp; Sinopec Fushun Research Institute of Petroleum and Petrochemicals
Current assignee: China Petroleum and Chemical Corp; Sinopec Fushun Research Institute of Petroleum and Petrochemicals
Priority date: 2016-11-24
Filing date: 2016-11-24
Publication date: 2020-09-11
Anticipated expiration: 2036-11-24
Also published as: CN108102702A

Abstract

The invention discloses a catalytic diesel oil processing method. The catalytic diesel raw material is divided into a light component and a heavy component; carrying out conversion reaction on the light components and a bed layer of the light aromatic hydrocarbon hydrogenation conversion catalyst to obtain conversion gasoline and conversion diesel oil; the heavy component is in contact reaction with a heavy aromatic hydrocarbon hydrogenation conversion catalyst to obtain converted gasoline and diesel oil fractions; the diesel oil fraction obtained by heavy component conversion is contacted with a medium aromatic hydrocarbon hydrogenation conversion catalyst for reaction, and the reaction effluent is then contacted with a light component hydrogenation conversion catalyst for reaction; the converted gasoline obtained from each part is mixed to obtain high-quality gasoline. The invention can process different types of raw materials selectively and independently through reasonable separation and processing processes, thereby being capable of reasonably utilizing inferior catalytic cracking diesel to produce qualified high-octane gasoline products.

Description

Method for processing catalytic diesel oil

Technical Field

The invention relates to a processing method of catalytic diesel oil, in particular to a method for processing catalytic cracking diesel oil to produce high-quality gasoline.

Background

Catalytic cracking is the most important secondary process in the petroleum refining industry at present, and is also the core process for heavy oil lightening. With the increasing weight of global petroleum, the processing capacity of the FCC device is continuously improved, various heavy oils are used as raw materials, the main product gasoline with high octane number is obtained through catalytic cracking reaction, and simultaneously, a large amount of catalytic diesel oil with high sulfur, nitrogen and aromatic hydrocarbon contents, low cetane number or cetane index and extremely poor stability is generated. And the requirements of environmental protection laws and regulations are increasingly strict, and the indexes of diesel products are gradually improved, so that strict requirements are imposed on the sulfur content, the aromatic hydrocarbon content, the cetane index and the like in the diesel products. Therefore, while the yield of the poor diesel oil is reduced, a proper method needs to be found for processing the poor diesel oil so as to meet the requirements of product delivery of enterprises.

The catalytic hydrogenation technology has important significance for improving the processing depth of crude oil, reasonably utilizing petroleum resources, improving product quality, improving yield of light oil and reducing atmospheric pollution, particularly has more remarkable importance for catalytic hydrogenation under the condition that the weight of the current petroleum resources is changed and the quality is deteriorated, can improve the hydrogen-carbon ratio in fuel oil products, optimizes product quality and improves emission standard through proper hydrogenation, becomes an indispensable component in the field of petrochemical industry at present, and can be divided into hydrogenation treatment and hydrocracking in the main process.

The catalytic diesel oil has very bad properties, so the current treatment means is single, and in China, the means which can be relied on mainly comprises the combined processing of the catalytic diesel oil and hydrogenation technology, such as the hydrofining after mixing the catalytic diesel oil and the straight-run diesel oil, the hydrocracking after mixing the catalytic diesel oil and the straight-run wax oil and the conversion technology which is used for producing gasoline by independently cracking the catalytic diesel oil in recent years.

CN1955257A introduces a method for producing high-quality chemical raw materials in more yield, which mainly mixes poor-quality catalytic cracking diesel oil and hydrogenation raw materials in proportion, and then produces catalytic reforming raw materials and high-quality ethylene raw materials by steam cracking through controlling reaction conditions. Although the catalytic cracking poor diesel oil can be processed, the processing path of poor raw materials is increased and the poor raw materials are converted into high-quality products, the proportion of blended catalytic diesel oil is still limited to a certain extent, the amount of the processable catalytic diesel oil is small, and the consumption of hydrogen for processing the catalytic diesel oil under the high-pressure condition is large.

CN103773455A the invention discloses a combined hydrogenation process of animal and vegetable oil and catalytic diesel, which essentially treats catalytic diesel through hydrofining, and although catalytic diesel can be processed through proper raw material proportion, the amount of catalytic diesel which can be blended is very small due to the limit of diesel product indexes, and the problem of treating a large amount of catalytic diesel of a large catalytic oil refining enterprise can not be thoroughly solved.

CN104611029A discloses a catalytic cracking diesel oil hydro-conversion method, wherein catalytic diesel oil and hydrogen gas are mixed and then enter a hydrofining reactor for hydrofining reaction, and then enter a hydrocracking reactor for hydrocracking reaction. Although the high-octane gasoline can be produced by processing and catalyzing diesel components through a certain catalyst grading action, the chemical hydrogen consumption is relatively high, and the requirement on hydrogen resources of enterprises is relatively high.

Disclosure of Invention

Aiming at the problems in the prior art, the technical problem to be solved by the invention is to provide a hydrocracking process method for processing catalytic diesel oil raw materials. The method comprises the steps of analyzing conventional catalytic diesel oil, cutting and separating to separate tricyclic and higher aromatic heavy components (simultaneously containing a small amount of aromatic hydrocarbons with single-ring and double-ring long side chains) and aromatic light components, wherein the heavy components directly generate high-octane gasoline after reaction, and the light components generate high-octane gasoline after light conversion reaction. When the catalytic diesel raw material is treated, all components are independently processed, the pertinence is strong, a high-quality gasoline product can be produced, and simultaneously compared with other technologies, the catalytic diesel raw material has the characteristics of high gasoline yield and good quality.

The invention provides a combined process method for processing catalytic diesel oil, which comprises the following steps:

a) cutting and separating the catalytic diesel raw material to obtain a light component and a heavy component;

b) the light component obtained in the step a) is used as raw oil and enters a bed layer containing hydrofining and light aromatic hydrocarbon hydro-conversion catalysts for conversion reaction to obtain reaction effluent, and the processes of gas-liquid separation, fractionation and the like are carried out to finally obtain conversion gasoline and conversion diesel oil;

c) the heavy component obtained in the step a) is used as raw oil and enters a reactor containing hydrofining and heavy aromatics hydroconversion catalysts for conversion reaction, and the obtained reaction effluent is subjected to gas-liquid separation, fractionation and other processes to finally obtain conversion gasoline and diesel fraction;

d) the diesel oil fraction in the step c) is used as raw oil and enters a bed layer containing a medium aromatic hydrocarbon hydrogenation conversion catalyst for conversion reaction, and the obtained reaction effluent continues to enter the bed layer in the step b) for reaction;

e) mixing the converted gasoline obtained in the step b) and the step c) to obtain high-quality gasoline.

The initial boiling point of the catalytic (cracking) diesel oil raw material in the step a) is generally 160-240 ℃, and preferably 180-220 ℃; the final distillation point is generally 320-420 ℃, and preferably 350-390 ℃; the content of aromatic hydrocarbon is generally more than 50wt%, preferably 60-90 wt%; wherein the aromatic hydrocarbon with more than three rings is generally more than 5wt percent, and preferably more than 10wt percent. The density of the catalytic diesel fuel stock is generally 0.91g ∙ cm^-3Above, preferably 0.93g ∙ cm^-3The above.

The catalytic diesel oil raw material can be a catalytic cracking product obtained by processing any basic oil species, for example, the catalytic cracking product can be selected from catalytic diesel oil obtained by processing middle east crude oil, and specifically can be catalytic diesel oil components obtained by processing Iran crude oil, Sauter crude oil and the like.

The cutting separation in the step a) is a conventional gas-liquid separation process, and a flash separation or tray separation mode which is well known in the industry can be adopted, so that the catalytic diesel oil is divided into a light part and a heavy part, and the division point is generally 290-350 ℃, preferably 300-340 ℃ according to the description in the method. The light component is a liquid phase fraction below the division point, and the heavy component is a liquid phase fraction above the division point.

The hydrofining catalyst in step b) comprises a carrier and a hydrogenation metal loaded. Based on the weight of the catalyst, the catalyst generally comprises a metal component of group VIB of the periodic table of elements, such as tungsten and/or molybdenum, accounting for 10-35 percent of oxide, preferably 15-30 percent; group VIII metals such as nickel and/or cobalt, in terms of oxides, are in the range of 1% to 7%, preferably 1.5% to 6%. The carrier is inorganic refractory oxide, and is generally selected from alumina, amorphous silica-alumina, silica, titanium oxide and the like. The conventional hydrocracking pretreatment catalyst can be selected from various conventional commercial catalysts, such as hydrogenation refining catalysts developed by the Fushu petrochemical research institute (FRIPP), such as 3936, 3996, FF-16, FF-26, FF-36, UDS-6 and the like; it can also be prepared according to the common knowledge in the field, if necessary.

The gas-liquid separation and fractionation processes described in step b) and step c) are well known to those skilled in the art. The gas-liquid separation is a separation process of products in the hydro-upgrading process, and generally mainly comprises a high-pressure separator, a low-pressure separator, a circulating hydrogen system and the like; the fractionation process is a process for further refining a liquid-phase product of gas-liquid separation, and generally mainly comprises a stripping tower, a fractionating tower, a side-line tower and the like.

The light aromatic hydrocarbon hydroconversion catalyst in the step b) is a hydroconversion catalyst containing a molecular sieve, and is a catalyst specially prepared according to the method. The hydrogenation conversion catalyst comprises hydrogenation active metal, a molecular sieve component and an alumina carrier. The general hydro-conversion catalyst is composed of hydrogenation active metal components such as Wo, Mo, Co, Ni and the like, a molecular sieve component, an alumina carrier and the like. The hydroconversion catalysts which are specific for the present invention comprise, by weight, WO₃(or MoO)₃) 5-15 wt%, NiO (or CoO) 3-8 wt%, molecular sieve 50-60 wt% and alumina 5-30 wt%, and the catalyst is characterized in that in the preparation process of the molecular sieve, unit cell parameters of 2.438-2.442 nm, infrared total acid 0.6-0.8 mmol/g and strong acid center 80% (mmol/g) can be obtained through modification^-1/mmol·g^-1) The modified molecular sieve may be a Y-type molecular sieve. The main function of the catalyst is to perform selective reaction on bicyclic aromatic hydrocarbon in raw materials, and the selectivity on other aromatic hydrocarbon is poor. The present hydroconversion catalyst is a proprietary technical catalyst that can be prepared according to the above description, following common general knowledge in the art.

The heavy aromatics hydroconversion catalyst of step c) is a hydroconversion catalyst comprising a molecular sieve, which is a catalyst specifically prepared according to the present method. The hydrogenation conversion catalyst comprises hydrogenation active metal, a molecular sieve component and an alumina carrier. The general hydro-conversion catalyst is composed of hydrogenation active metal components such as Wo, Mo, Co, Ni and the like, a molecular sieve component, an alumina carrier and the like. The hydroconversion catalysts which are specific for the present invention comprise, by weight, WO₃(or MoO)₃) 9-29 wt%, NiO (or CoO) 5-10 wt%, Y-type molecular sieve 15-45 wt% and alumina 20-50 wt%.

In the heavy aromatics hydroconversion catalyst, the Y-type molecular sieve is a small-grain Y-type molecular sieve. SmallThe grain size of the crystal grain Y-type molecular sieve is 400-600 nm, the infrared total acid is 0.3-0.7 mmol/g, the proportion of the medium strong acid is more than 85%, and the unit cell parameter is 2.435-2.440 nm; the pore volume is 0.5-0.7 cm³The proportion of the 2-8nm secondary pore volume in the total pore volume is more than 50%. The Y-type molecular sieve has more accessible and exposed acid centers, is beneficial to the diffusion of hydrocarbon molecules, can improve the preferential conversion capacity of cyclic hydrocarbon, particularly tricyclic aromatic hydrocarbon, directionally saturates and breaks the aromatic ring in the tricyclic aromatic hydrocarbon, and produces the gasoline component with high octane number to the maximum extent. The hydroconversion catalyst containing the small-grain Y-shaped molecular sieve has the main function of performing selective reaction on tricyclic aromatic hydrocarbon in raw materials, and has poor selectivity on non-tricyclic two-ring and monocyclic aromatic hydrocarbon. The Y-type molecular sieve has a certain difference with the conventional Y-type molecular sieve, the grain size of the conventional modified molecular sieve is generally 800-1200 nm, and the pore volume is 0.35-0.50 cm³The proportion of secondary pore volume to total pore volume is generally 30-50%, and the proportion of medium-strong acid is 50-70%. The hydroconversion catalyst may be used to prepare a satisfactory catalyst in accordance with common general knowledge in the art, as described above.

In step c), the hydroconversion catalyst preferably adopts a catalyst grading filling scheme. The hydroconversion catalyst comprises at least two catalyst beds, and according to the contact sequence of the hydroconversion catalyst and the reaction materials, the unit cell parameter of the Y-type molecular sieve in the catalyst of the upstream bed is generally 2.435-2.438 nm, and the infrared total acid is 0.3-0.5 mmol/g; the unit cell parameter of the Y-type molecular sieve in the catalyst in the downstream bed layer is generally 2.438-2.440 nm, and the infrared total acid is 0.5-0.7 mmol/g. Compared with the catalyst in the upstream bed layer, the proportion of the secondary pores in the catalyst in the downstream bed layer to the total pore volume is 2-15 percent lower, and the content of the Y-type molecular sieve is 5-15 percent higher. The modification treatment process of the Y-type molecular sieve satisfying the requirement can be performed by using the conventional technology in the art, for example, the method described in CN104588073A can be referred to for the treatment of the Y-type molecular sieve.

According to the difference between the unit cell parameters of the Y-type molecular sieve and the total infrared acid amount, the catalysts can be matched according to the difference of the activity. Therefore, the hydrogenation performance and the cracking performance of the catalyst can be more reasonably excessive along the flowing direction of reaction materials, the hydrogenation and cracking processes are more specifically carried out on reactants, particularly tricyclic complex aromatic hydrocarbons, the middle ring of the catalyst is subjected to saturation cracking, and the catalyst is further directionally converted into a gasoline component with a high octane number to the maximum extent, so that the content of polycyclic aromatic hydrocarbons in the product can be greatly reduced, and the selectivity of the hydrogenation conversion is further improved.

The catalyst filled by adopting the grading technology is contacted with a catalytic diesel heavy component containing a large amount of tricyclic aromatic hydrocarbon and a proper amount of bicyclic aromatic hydrocarbon for reaction, and the tricyclic aromatic hydrocarbon has strong polarity, strong adsorption capacity and low cracking difficulty, so that the upstream catalyst has proper molecular sieve content and secondary pore proportion and moderate acidity, the tricyclic aromatic hydrocarbon can be effectively and directly converted into a high-octane gasoline component containing monocyclic aromatic hydrocarbon, and the molecular sieve and secondary pore proportion in the downstream catalyst is slightly high. The acidity is strong, and the bicyclic aromatic hydrocarbon can be further converted into a high-octane gasoline component containing monocyclic aromatic hydrocarbon, so that most of the bicyclic aromatic hydrocarbon can be directly converted into a target product according to the reaction difficulty of different components in the raw materials by adopting the catalyst grading scheme, and the selectivity is further improved.

The intermediate aromatic hydrocarbon hydroconversion catalyst in the step d) is a hydroconversion catalyst containing a molecular sieve, and is a catalyst specially prepared according to the method. The hydrogenation conversion catalyst comprises hydrogenation active metal, a molecular sieve component and an alumina carrier. The general hydro-conversion catalyst is composed of hydrogenation active metal components such as Wo, Mo, Co, Ni and the like, a molecular sieve component, an alumina carrier and the like, and the content of the hydrogenation components is 2-20% by weight of the catalyst. The hydroconversion catalysts which are specific for the present invention comprise, by weight, WO₃(or MoO)₃) The catalyst is characterized in that in the preparation process of the molecular sieve, the modified molecular sieve with unit cell parameters of 2.434-2.439 nm, infrared total acid of 0.4-0.6 mmol/g and strong acid center of more than 60% can be obtained through modification, and can be a Y-type molecular sieve. Its main function isTo selectively react with respect to the aromatic hydrocarbons in the feedstock. The hydroconversion catalyst may be a proprietary technical catalyst prepared in accordance with common general knowledge in the art, as described above.

In the present invention, the technical terms "medium strong acid" and "strong acid" are conventional concepts well known to those skilled in the art. In the technical field of catalyst preparation, NH is adopted as medium-strong acid₃TPD was analyzed, with 150 ℃ desorption defined as weak acid, 250 ℃ desorption defined as medium strong acid, and 400 ℃ desorption defined as strong acid.

The reaction conditions for the conversion reactions described in step b), step c) and step d) are: the volume space velocity is 0.5-4.0 h^-1Preferably 0.8 to 2.5 hours^-1(ii) a The hydrogen partial pressure is 4-13 MPa, preferably 6-10 MPa; the volume ratio of the hydrogen to the oil at the inlet is 300: 1-800: 1, preferably 400: 1-700: 1; the reaction temperature is 360-430 ℃, and preferably 380-420 ℃. According to the difference of cutting point and aromatic hydrocarbon distribution, the conversion reaction can control a certain conversion depth according to the content of tricyclic aromatic hydrocarbon in the raw material, and generally (control)>290 deg.C) of not more than 80%, preferably not more than 60%.

The high-quality gasoline in the step e) is a high-quality component which can enter a blending pool for blending finished product oil.

Compared with the prior art, the catalytic diesel oil combined processing method has the following advantages:

1. the catalytic diesel oil with high aromatic hydrocarbon content is processed, different types of aromatic hydrocarbon mixtures are respectively processed in a targeted manner through a cutting process of light-heavy separation, tricyclic aromatic hydrocarbon, two-ring and single-ring heavy components and two-ring and single-ring light components which are most suitable as a hydrogenation conversion raw material can be subjected to conversion reaction, and the gasoline component with high octane number can be produced to the maximum extent by matching with the preparation of a catalyst, a grading technology and parameter control in the process. The method can process different types of raw materials independently in a targeted manner through reasonable separation and processing processes, simplifies the complex petroleum refining process, and maximizes the processing suitability and pertinence of each component while considering the processing difficulty when processing poor-quality catalytic diesel oil, thereby having great advantages. According to different preparation processes of the catalyst, the catalyst reacts aiming at a specific raw material, wherein the light aromatic hydrocarbon hydrogenation conversion catalyst can carry out a specific reaction aiming at two-ring light aromatic hydrocarbon, the middle aromatic hydrocarbon hydrogenation conversion catalyst with lower activity can carry out a specific reaction aiming at two-ring heavy aromatic hydrocarbon, the heavy aromatic hydrocarbon hydrogenation conversion catalyst with lower activity can carry out a specific reaction aiming at three-ring aromatic hydrocarbon, and the catalyst jointly play a role in converting aromatic hydrocarbon in the raw material into a high-octane gasoline component to the maximum extent.

2. The method deeply couples the separation and the hydroconversion of different types in the process flow, and obtains ideal comprehensive processing effect on the basis of pertinently treating raw materials and improving the product quality. Although each unit has stronger independence in the description process, different units can be organically combined and shared in practical application, so that the method has the advantages of equipment saving, low operation cost and the like, and simultaneously, due to the improvement of a heat exchange system caused by combination, the energy consumption of the device is reduced to a certain extent, the investment is reduced, and the method has wide application prospect.

3. According to the method, a new series of conversion catalysts with stronger pertinence is developed on the basis of the original catalytic diesel oil hydroconversion catalyst, and the method is also a great embodiment of technical progress, can provide more catalyst selection directions for enterprises, and brings more visual economic benefits. The small crystal grain molecular sieve used by the hydro-conversion catalyst has large specific surface, especially obviously increased external surface area, sharply increased ratio of surface atomic number to volume atomic number, shortened pore passage and increased exposed pore opening, so that the small crystal grain molecular sieve has higher reaction activity and surface energy and shows obvious volume effect and surface effect. Specifically, the following aspects are provided: because the external surface area is increased, more active centers are exposed, the diffusion effect is effectively eliminated, the catalyst efficiency is fully exerted, and the reaction performance of macromolecules is improved; the surface energy is increased, so that the adsorption capacity of the molecular sieve is increased, the adsorption speed is accelerated, and the effective adsorption capacity of the molecular sieve is improved; the small-crystal molecular sieve has short pore passage and small in-crystal diffusion resistance, and the huge external surface area enables more orifices of the small-crystal molecular sieve to be exposed outside, so that the small-crystal molecular sieve is beneficial to the rapid in-and-out of reactant or product molecules, and can prevent or reduce the formation of carbon deposition caused by the accumulation of the product in the pore passage, thereby improving the turnover rate of the reaction and the service life of the molecular sieve; has uniform radial distribution of the skeleton components, thereby improving activity and selectivity; the method is more beneficial to the realization of the modification technology after the synthesis of the molecular sieve; for molecular sieve supported metal catalysts, the use of small crystallite molecular sieves is beneficial in increasing the effective loading of the metal component and improving the dispersion properties of the metal component. In addition, the proportion of secondary pores in the molecular sieve can be further increased through subsequent modification treatment, the pore structure of the molecular sieve is unblocked, macromolecule adsorption reaction and desorption are facilitated, the directional hydrogenation conversion capability of macromolecule heavy aromatics is greatly enhanced, and the saturation and cracking of the intermediate ring can enable high-octane gasoline components in the product to be more.

Drawings

FIG. 1 is a schematic flow diagram of the process of the present invention.

Detailed Description

The combined process of the present invention will be described in detail with reference to the accompanying drawings. Only the main description of the process flow is given in fig. 1, and some necessary equipment and vessels are also omitted from the schematic.

As shown in figure 1, the combined process flow for processing catalytic diesel oil of the invention is as follows: after a catalytic diesel raw material 1 enters a separator 2, a light component 3 is obtained at the upper part, a heavy component 4 is obtained at the lower part, the light component 3 is mixed with hydrogen 5 and then enters a light aromatic hydrocarbon hydrogenation conversion reaction zone to be in contact reaction with catalysts 8 and 9, a reaction effluent 10 enters a separation and fractionation system 11, conversion gasoline 12 is discharged from the upper part, and conversion diesel 13 is obtained at the bottom; mixing the heavy component 4 with hydrogen 14, entering a heavy aromatic hydrocarbon hydrogenation conversion reaction zone, carrying out contact reaction with catalysts 15 and 16 (namely graded heavy aromatic hydrocarbon hydrogenation conversion catalysts A and B), enabling a reaction effluent 17 to enter a separation and fractionation system 18, discharging conversion gasoline 20 from the upper part, enabling a diesel fraction 19 obtained at the bottom to be circularly mixed with hydrogen 6, entering a medium aromatic hydrocarbon hydrogenation conversion reaction zone, reacting with a catalyst 7, and enabling the effluent to enter a light aromatic hydrocarbon hydrogenation conversion reaction zone according to the material flow direction; the conversion gasoline 12 is mixed with the conversion gasoline 20 to obtain high-quality gasoline 21. Wherein

catalysts

8 and 15 are hydrofinishing catalysts.

The combined process of the present invention is further illustrated by the following specific examples.

Example 1

The combined process flow shown in figure 1 is adopted, catalytic diesel oil is selected as a raw material to carry out hydrogenation production, the cutting point of light and heavy components is 300 ℃, and the target products are high-quality gasoline and diesel oil. The catalysts used in the examples are commercial catalyst FF-36 hydrotreating catalyst and special hydroconversion catalyst (light aromatics, medium aromatics, heavy aromatics A) of the present technology.

Example 2

The combined process flow shown in figure 1 is adopted, catalytic diesel oil is selected as a raw material to carry out hydrogenation production, the cutting point of light and heavy components is 300 ℃, and the target products are high-quality gasoline and diesel oil. The catalysts used in the examples were a commercial catalyst FF-36 hydrotreating catalyst and a special hydroconversion catalyst of the present technology (light aromatics, medium aromatics, heavy aromatics A and B, with the balance being alumina in the catalyst composition except for the metal oxides and Y-type molecular sieves listed in the table).

Example 3

The combined process flow shown in figure 1 is adopted, catalytic diesel oil is selected as a raw material to carry out hydrogenation production, the cutting point of light and heavy components is 310 ℃, and target products are high-quality gasoline and diesel oil. The catalysts used in the examples were a commercial catalyst FF-36 hydrotreating catalyst and a special hydroconversion catalyst of the present technology. (light, Medium, heavy aromatics A and B)

Comparative example 1

The technological process shown in figure 1 is adopted, catalytic diesel oil is selected as a raw material to carry out hydrogenation production, the cutting point of light and heavy components is 300 ℃, and target products are high-quality gasoline and diesel oil. The catalysts used in the comparative examples were a commercial catalyst FF-36 hydrotreating catalyst, a 3963 hydro-upgrading catalyst, and a conventional hydroconversion catalyst C.

Comparative example 2

Comparative example 2 is a conventional catalytic diesel hydroconversion process, catalytic diesel is selected as a raw material for hydrogenation production, and the target products are high-quality gasoline and common diesel. The catalysts used in the comparative examples were a commercial catalyst FF-36 hydrotreating catalyst and a conventional hydroconversion catalyst C.

The properties of the specific and conventional hydroconversion catalysts are shown in Table 1, the properties of the feedstock are shown in Table 2, the operating conditions are shown in Table 3, and the properties of the main products are shown in Table 4.

TABLE 1 hydroconversion catalysts Primary physicochemical Properties

Table 2 raw oil properties table.

Table 3 reaction conditions.

The reaction conditions are shown in Table 3.

As can be seen from the examples and comparative examples in tables 2 and 3, the present technology has a great advantage in hydrogen consumption for the production of gasoline by processing a large amount of catalytic diesel.

TABLE 4 Main Properties of the product

It can be seen from the above examples that when the catalytic diesel oil raw material is treated by the method of the present invention, compared with the comparative example, the properties and yield of the produced naphtha and diesel oil products have certain advantages when the catalytic diesel oil is processed under the same working condition.

It can be seen from the above examples and comparative examples that the catalytic diesel raw material is cut and then processed respectively by the method, so that inferior diesel components can be treated to the maximum extent, the diesel-steam ratio can be flexibly adjusted according to the actual conditions of enterprises, and the production can be carried out according to the change of market demands.

Different types of hydro-conversion processes are combined in the aspects of process flow and catalyst, and an ideal comprehensive processing effect is obtained on the basis of pertinently treating raw materials and improving the product quality. Although each unit has stronger independence in the description process, different units can be combined organically and shared in practical application, so that the method has the advantages of equipment saving, low operation cost and the like, and simultaneously, due to the improvement of a heat exchange system caused by combination, the energy consumption of the device is reduced to a certain extent, the investment is reduced, and the method has wide application prospect.

Claims

1. A combined process for processing catalytic diesel oil, comprising the steps of:

a) cutting and separating the catalytic diesel raw material to obtain a light component and a heavy component; the cutting temperature of the light component and the heavy component is 290-350 ℃;

b) the light component obtained in the step a) is used as raw oil and enters a bed layer containing a hydrofining catalyst and a light aromatic hydrocarbon hydro-conversion catalyst for conversion reaction to obtain a reaction effluent, and the reaction effluent is subjected to gas-liquid separation and fractionation processes to finally obtain converted gasoline and converted diesel oil;

c) the heavy component obtained in the step a) is used as raw oil and enters a reactor containing a hydrofining catalyst and a heavy aromatics hydroconversion catalyst for conversion reaction, and the obtained reaction effluent is subjected to gas-liquid separation and fractionation processes to finally obtain conversion gasoline and diesel fraction;

e) mixing the converted gasoline obtained in the step b) and the step c) to obtain high-quality gasoline;

the heavy aromatic hydrocarbon hydrogenation conversion catalyst comprises hydrogenation active metal, a Y-type molecular sieve component and an alumina carrier, wherein the Y-type molecular sieve is a small-grain Y-type molecular sieve, the grain size of the small-grain Y-type molecular sieve is 400-600 nm, the infrared total acid is 0.3-0.7 mmol/g, the proportion of medium strong acid is more than 85%, and the unit cell parameter is 2.435-2.440 nm; the pore volume is 0.5-0.7 cm³The proportion of the 2-8nm secondary pore volume in the total pore volume is more than 50%;

the heavy aromatics hydroconversion catalyst in the step c) comprises at least two catalyst beds, and compared with the catalyst in the upstream catalyst bed, the proportion of secondary pores in the catalyst in the downstream bed to the total pore volume is 2-15% lower, and the content of the Y-type molecular sieve is 5-15% higher according to the contact sequence of the catalyst and the reaction materials.

2. The combined process of claim 1, wherein the catalytic diesel feedstock has an initial boiling point of 160-240 ℃, an end point of 320-420 ℃, and an aromatic content of 50wt% or more.

3. The combined process of claim 2, wherein the catalytic diesel feedstock has an initial boiling point of 180 to 220 ℃, an end point of 350 to 390 ℃, and an aromatic content of 60 to 90 wt%.

4. The combined process of claim 1 wherein the cut temperature of the light and heavy components is from 300 ℃ to 340 ℃.

5. The integrated process of claim 1 wherein said light aromatics hydroconversion catalyst comprises, by weight, WO₃Or MoO₃5-15 wt%, NiO or CoO 3-8 wt%, Y-type molecular sieve 50-60 wt% and alumina 5-30 wt%.

6. The combined process of claim 5, wherein the unit cell parameters of the Y-type molecular sieve are 2.438 to 2.442nm, the total infrared acid is 0.6 to 0.8mmol/g, and the center of the strong acid is more than 80%.

7. The integrated process of claim 1 wherein said heavy aromatics hydroconversion catalyst comprises, by weight, WO₃Or MoO₃9-29 wt%, NiO or CoO 5-10 wt%, Y-type molecular sieve 15-45 wt% and alumina 20-50 wt%.

8. The integrated process of claim 1 wherein said medium aromatics hydroconversion catalyst comprises, by weight, WO₃Or MoO₃7-17 wt%, NiO or CoO 4-9 wt%, Y-type molecular sieve 40-60 wt% and alumina 5-30 wt%.

9. The combined process of claim 8, wherein the unit cell parameters of the Y-type molecular sieve are 2.434-2.439 nm, the total infrared acid is 0.4-0.6 mmol/g, and the strong acid center is above 60%.

10. The combined process method of claim 1, wherein the unit cell parameters of the Y-type molecular sieve in the catalyst of the upstream bed layer are 2.435-2.438 nm, and the total infrared acid is 0.3-0.5 mmol/g; the unit cell parameter of the Y-type molecular sieve in the catalyst in the downstream bed layer is 2.438-2.440 nm, and the infrared total acid is 0.5-0.7 mmol/g.

11. The combined process of claim 1, wherein the hydroconversion reaction in step b), step c) and step d) is carried out under the following conditions: the volume space velocity is 0.5-4.0 h^-1The hydrogen partial pressure is 4-13 MPa, the volume ratio of hydrogen to oil at the inlet is 300: 1-800: 1, and the reaction temperature is 360-430 ℃.

12. The integrated process of claim 11 wherein said hydroconversion reaction is carried out under process conditions selected from the group consisting of: the volume space velocity is 0.8-2.5 h^-1Hydrogen partial pressure of 6 to 10MPa, inThe volume ratio of the hydrogen to the oil is 400: 1-700: 1, and the reaction temperature is 380-420 ℃.

13. The integrated process of claim 11 or 12 wherein the mass conversion in step (c) is controlled to a tricyclic aromatic hydrocarbon >290 ℃ of not more than 80%.

14. The integrated process of claim 13 wherein the mass conversion in step (c) to control tricyclic aromatic hydrocarbon >290 ℃ is not greater than 60%.