CN108102709B

CN108102709B - Processing method of catalytic diesel oil

Info

Publication number: CN108102709B
Application number: CN201611045497.4A
Authority: CN
Inventors: 李本哲; 王仲义; 崔哲; 彭冲; 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: 2020-05-19
Anticipated expiration: 2036-11-24
Also published as: CN108102709A

Abstract

The invention discloses a processing method of catalytic cracking diesel oil. Cutting a catalytic diesel raw material into a light component and a heavy component; carrying out hydrofining and hydro-conversion reaction on the light component to obtain gasoline and diesel oil components; separating the obtained heavy components to obtain tricyclic aromatic hydrocarbon components and non-tricyclic aromatic hydrocarbon components; hydrofining and hydro-conversion are carried out on the obtained non-tricyclic aromatic hydrocarbon, and hydrofining and hydro-conversion are carried out on the obtained tricyclic aromatic hydrocarbon component to obtain a gasoline component and a diesel oil component; mixing gasoline of each part to obtain gasoline product, and mixing diesel oil components of each part to obtain diesel oil product. 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 gasoline and diesel products.

Description

Processing method of 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 a large quantity, 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 monocyclic and bicyclic aromatic hydrocarbons with long side chains) and aromatic light components, passing the heavy components through an aromatic separation device to obtain tricyclic aromatic hydrocarbons and non-tricyclic aromatic hydrocarbons, respectively reacting to directly generate high-octane gasoline, and carrying out shallow conversion reaction on the light components to generate high-octane gasoline. 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 processing method of 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, and the obtained reaction effluent is subjected to gas-liquid separation, fractionation and other processes to finally obtain converted gasoline, converted diesel oil and the like;

c) the heavy component obtained in the step a) enters an aromatic hydrocarbon separation device, and a tricyclic aromatic hydrocarbon component and a non-tricyclic aromatic hydrocarbon component in the heavy component are separated;

d) the non-tricyclic aromatic hydrocarbon component serving as raw oil enters a bed layer containing hydrofining and medium aromatic hydrocarbon hydrogenation conversion catalysts for conversion reaction, and the obtained reaction effluent continuously enters the light aromatic hydrocarbon hydrogenation conversion catalyst bed layer in the step b) for reaction;

e) the tricyclic aromatic hydrocarbon component as raw oil enters a bed layer containing hydrofining and heavy aromatic hydrocarbon hydro-conversion catalysts for conversion reaction, and the obtained reaction effluent is subjected to gas-liquid separation, fractionation and other processes to finally obtain converted gasoline, converted diesel oil and the like;

f) mixing the converted gasoline obtained in the step b) with the converted gasoline obtained in the step e) to obtain a gasoline product; the converted diesel oil of step e) is directly mixed with the converted diesel oil of step b) to be used as a diesel oil product, or is recycled to be mixed with the non-tricyclic aromatic components in step d) as a raw material.

The initial boiling point of the catalytic diesel oil component in the step a) is generally 160-240 ℃, preferably 180-220 ℃, the final boiling point is generally 320-420 ℃, preferably 350-390 ℃, the aromatic hydrocarbon content is generally more than 50wt%, preferably 60-90 wt%, wherein the tricyclic aromatic hydrocarbon is generally more than 5wt%, preferably more than 10 wt%; the density of the diesel fuel stock is generally 0.91g cm^-3Above, preferably 0.93 g/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 described in step b) and step c) comprises a support and a hydrogenation metal supported. Based on the weight of the catalyst, the catalyst generally comprises 10-35% of metal components in VIB group of the periodic table of elements, such as tungsten and/or molybdenum, calculated by oxide, and preferably 15-30%; group VIII metals such as nickel and/or cobalt are present in amounts of 1% to 7%, preferably 1.5% to 6%, calculated as oxides. 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) 5-25 wt%, NiO (or CoO) 3-8 wt%, molecular sieve 50-60 wt% and alumina 15-35 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 hydroconversion catalyst may be supportedA proprietary technical catalyst prepared in accordance with common general knowledge in the art is described above.

The intermediate aromatic hydrocarbon hydroconversion catalyst in the step c) 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) 7-27 wt%, NiO (or CoO) 4-9 wt%, molecular sieve 30-49 wt% and alumina 30-50 wt%, and 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 0.4-0.6 mmol/g and strong acid center above 60% can be obtained through modification, and can be a Y-type molecular sieve. The main function of the method is to perform selective reaction aiming at aromatic hydrocarbon in the raw material. 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 35-60 wt%.

In the heavy aromatics hydroconversion catalyst, 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 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 secondary pore volume to the total pore volume is more than 50 percent. The Y shapeThe 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 hydrocarbons, particularly tricyclic aromatic hydrocarbons, directionally saturates and breaks aromatic rings in the tricyclic aromatic hydrocarbons, and produces gasoline components 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 the secondary pore volume of 2-8nm in the total pore volume is generally 30-50%, and the proportion of the 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 the present invention, the technical terms "medium strong acid" and "strong acid" are conventional concepts in the field of catalyst preparation. It employs NH₃TPD, with 150-250 ℃ desorption being defined as weak acid, 250-400 ℃ desorption as medium strong acid and 400-500 ℃ desorption as strong acid.

In the step c), the heavy aromatics 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.

The catalyst can be graded according to the difference of activity according to the difference of unit cell parameters of the Y-type molecular sieve in the hydro-conversion catalyst and the total infrared acid amount. Therefore, the hydrogenation performance and the cracking performance of the catalyst can be more reasonably transited along the flowing direction of reaction materials, reactants, particularly tricyclic complex aromatic hydrocarbon in the reactants, are more purposefully subjected to hydrogenation and cracking processes, the aromatic ring in the middle of the reactants is subjected to saturation cracking, and the reactants are further directionally converted into gasoline components with high octane number to the greatest extent, so that the content of polycyclic aromatic hydrocarbon in products can be greatly reduced, and the selectivity of hydrogenation conversion is further improved.

In the invention, the heavy aromatics hydrogenation conversion catalyst preferably adopts a grading filling technology, the upstream catalyst firstly contacts with a catalytic diesel heavy component containing a large amount of tricyclic aromatics and a proper amount of bicyclic aromatics for reaction, and the tricyclic aromatics have stronger polarity, strong adsorption capacity and low cracking difficulty, so the upstream catalyst has proper molecular sieve content and secondary pore proportion and moderate acidity, and can effectively directly convert the tricyclic aromatics into the high-octane gasoline component containing monocyclic aromatics; the molecular sieve content and the proportion of secondary pores in the downstream catalyst are 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. Therefore, by adopting the catalyst grading scheme, most of aromatic hydrocarbon in the raw materials can be directly converted into a target product according to the reaction difficulty of different components in the raw materials, and the selectivity is further improved.

The aromatic hydrocarbon separation device in the step c) is a physical extraction process, and the principle is a process of extracting by utilizing the solubility difference of solvents for different substances and then separating. The solvent used for extraction can be sulfolane, furfural, NMP or phenol, etc. The process can be realized by using an aromatic hydrocarbon extraction or furfural refining device which is widely used in industry, and a furfural refining unit is preferred. The operating conditions of the extraction part of the furfural refining unit are as follows: the pressure in the tower is 0.01-0.8 MPa, the temperature is 50-150 ℃, the mass ratio of the solvent is 1-8, and the circulating mass ratio is 0-0.6; preferred operating conditions are: the pressure in the tower is 0.02-0.1 MPa, the temperature is 60-110 ℃, the mass ratio of the solvent is 2-7, and the circulating mass ratio is 0.2-0.5. The aromatic hydrocarbon separation device in the step c) can also be an adsorption separation process, and an appropriate molecular sieve is selected or prepared to perform an effective adsorption process by utilizing the difference of the sizes of different types of molecules, and then the steps of desorption separation and the like are performed, so that an ideal component is separated from a non-ideal component.

The reaction conditions of the conversion reaction in step b) and step c) are as follows: the volume space velocity is 0.5-4.0 h^-1Preferably 0.8 to 2.5 hours^-1The hydrogen partial pressure is 4-13 MPa, preferably 6-10 MPa, the inlet hydrogen-oil volume ratio is 300: 1-800: 1, preferably 400: 1-700: 1, and the reaction temperature is 360-430 ℃, preferably 380-420 ℃. According to the difference of cutting points 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. The present invention generally controls the mass conversion above the cut point in step a) not higher than 80%, preferably not higher than 60%.

The gasoline product and the diesel oil product in the step f) are high-quality components which can enter a blending pool for blending finished 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, after the catalytic diesel oil passes through a cutting process of light-heavy separation and an aromatic hydrocarbon separation device, different types of aromatic hydrocarbon mixture are independently processed, tricyclic aromatic hydrocarbon, two-ring and single-ring heavy components and two-ring and single-ring light components which are most suitable as hydrogenation conversion raw materials can be subjected to conversion reaction, and the gasoline component with high octane number can be produced in high yield 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 the two-ring light aromatic hydrocarbon, the middle aromatic hydrocarbon hydrogenation conversion catalyst with lower activity can carry out a specific reaction aiming at the two-ring aromatic hydrocarbon, the heavy aromatic hydrocarbon hydrogenation conversion catalyst with lower activity can carry out a specific reaction aiming at the three-ring aromatic hydrocarbon, and the catalyst jointly play a role in converting the 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 heavy component 4 enters an aromatic hydrocarbon separation device 5, a non-tricyclic component 6 is obtained at the upper part, a tricyclic component 7 obtained at the bottom part is mixed with hydrogen 8 and then enters a heavy aromatic hydrocarbon hydrogenation conversion reaction zone, after the heavy aromatic hydrocarbon hydrogenation conversion reaction zone is in contact reaction with catalysts 9 and 10 (namely graded heavy aromatic hydrocarbon hydrogenation conversion catalysts A and B), an effluent 11 enters a separation and fractionation system 12, a conversion gasoline 13 is discharged from the upper part, and a conversion diesel 14 is obtained at the bottom part; mixing the light component 3 with hydrogen 15, entering a light aromatic hydrocarbon hydrogenation conversion reaction zone, contacting and reacting with catalysts 16 and 17, then entering an effluent 18 into a separation and fractionation system 19, discharging conversion gasoline 20 from the upper part, and obtaining conversion diesel oil 21 from the bottom; the non-tricyclic component 6 and hydrogen 22 are mixed and then enter a medium aromatic hydrocarbon hydrogenation conversion reaction zone, and after the mixture is in contact reaction with catalysts 23 and 24, the effluent enters a light aromatic hydrocarbon hydrogenation conversion reaction zone according to the material flow direction; mixing the converted gasoline 13 and the converted gasoline 20 to obtain qualified gasoline 26; the converted diesel oil 14 can be recycled to the middle aromatic hydrocarbon hydrogenation conversion reaction zone to be mixed with the non-tricyclic component 6, and can also be mixed with the converted diesel oil 21 to obtain qualified diesel oil 25. Wherein the

catalysts

9, 16 and 23 are hydrofining catalysts.

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

The aromatic separation apparatus referred to in the following examples and/or comparative examples were operated under the following conditions: furfural is selected as an extraction solvent, the tower pressure is controlled to be 0.04-0.13 MPa, the temperature is 50-90 ℃, the solvent ratio is 3, the circulation ratio is 0.3, and different types of aromatic hydrocarbons can be ideally separated.

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 of the technology (light aromatics, medium aromatics, heavy aromatics A. in catalyst composition, the balance is alumina).

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).

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 special and conventional hydroconversion catalysts are shown in Table 1, the properties of the raw oil are shown in Table 2, the operating conditions are shown in Table 3 and the following Table 3, and the properties of the main products are shown in Table 4.

Table 1 the main physicochemical properties of the catalysts tailored by this technique.

Type (B)	Light aromatic hydrocarbons	Middle aromatic hydrocarbon	Heavy aromatic hydrocarbons A	Heavy aromatic hydrocarbons B	Conventional agent C
						Chemical composition	Mo-Ni	Mo-Ni	Mo-Ni	Mo-Ni	Mo-Ni
Content of metal oxide, wt.%	17.8	19.3	21.5	20.7	17.1
						Physical Properties
Appearance shape	Cylindrical bar	Cylindrical bar	Cylindrical bar	Cylindrical bar	Cylindrical bar
						Crush strength, N/cm	≥150	≥150	≥150	≥150	≥150
Particle diameter, mm	1.1~1.3	1.1~1.3	1.1~1.3	1.1~1.3	1.1~1.3
						Wt% of Y-type molecular sieve	55	49	35	45	50
Property of Y-type molecular sieve
						Particle size, nm	750	800	550	450	990
Cell parameter, nm	2.442	2.439	2.435	2.438	2.438
						The secondary pores account for v% of the total pore volume	44.0	55.0	66.0	61.0	50.1
Total infrared acid, mmol/g	0.65	0.56	0.35	0.55	0.60
						Proportion of (medium) strong acid%	81	62	85	87	58

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.

	Example 1	Example 2	Example 3	Comparative example 1	Comparative example 2
						Naphtha (a)
Research octane number	90.9	91.7	91.9	90.4	92.7
						Sulfur/. mu.g.g^-1	4.1	2.6	3.5	5.4	2.8
Yield/standard	Base +2.2%	Benchmark +3.2%	Reference +3.0%	Benchmark +1.8%	Datum
						Diesel oil
Cetane number	36.5	38.5	38.5	35.7	35.0
						Sulfur/. mu.g.g^-1	9.0	6.5	5.6	4.0	9.6

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 processing method of catalytic diesel oil comprises the following steps:

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 hydrofining and light aromatic hydrocarbon hydro-conversion catalysts for conversion reaction, and the obtained reaction effluent is subjected to gas-liquid separation and fractionation processes to obtain converted gasoline and converted diesel oil;

d) the non-tricyclic aromatic hydrocarbon component obtained in the step c) is used as raw oil and enters a bed layer containing hydrofining and medium aromatic hydrocarbon hydrogenation conversion catalysts for conversion reaction, and the obtained reaction effluent continuously enters the light aromatic hydrocarbon hydrogenation conversion catalyst bed layer in the step b) for reaction;

e) the tricyclic aromatic hydrocarbon component obtained in the step c) is used as raw oil and enters a bed layer containing hydrofining and heavy aromatic hydrocarbon hydro-conversion catalysts for conversion reaction, and gas-liquid separation and fractionation operations are carried out on the obtained reaction effluent to obtain converted gasoline and converted diesel oil;

f) mixing the converted gasoline obtained in the step b) with the converted gasoline obtained in the step e) to obtain a gasoline product; directly mixing the converted diesel oil obtained in the step e) with the converted diesel oil obtained in the step b) to be used as a diesel oil product, or recycling the diesel oil as a raw material to be mixed with a non-tricyclic aromatic component in the step d);

the heavy aromatics hydroconversion catalyst comprises hydrogenation active metal, a Y-type molecular sieve and an alumina carrier; the particle size of the 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 secondary pore volume to the total pore volume is more than 50 percent;

the heavy aromatics hydroconversion catalyst in the step e) comprises at least two catalyst beds, and compared with the catalyst in the upstream 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 method of claim 1, wherein the catalytic diesel feedstock has a primary boiling point of 160 to 240 ℃, a final boiling point of 320 to 420 ℃, an aromatic content of 50wt% or more, and a density of 0.91 g-cm^-3The above.

3. The method 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%; the density of the catalytic diesel fuel raw material is 0.93g cm^-3The above.

4. The method of claim 1 wherein the light and heavy components are separated at a temperature of 300 to 340 ℃.

5. The process of claim 1 wherein said light aromatic hydroconversion catalyst comprises WO₃Or MoO₃5-25 wt%, NiO or CoO 3-8 wt%, Y-type molecular sieve 50-60 wt% and alumina 15-35 wt%.

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

7. The process of claim 1 wherein said medium aromatics hydroconversion catalyst comprises, by weight, WO₃Or MoO₃7-27 wt%, NiO or CoO 4-9 wt%, Y-type molecular sieve 30-49 wt% and alumina 30-50 wt%.

8. The method according to claim 7, wherein the unit cell parameters of the Y-type molecular sieve are 2.434-2.439 nm, the infrared total acid is 0.4-0.6 mmol/g, and the strong acid center is more than 60%.

9. The process of claim 1 wherein said heavy aromatics hydroconversion catalyst comprises WO, by weight₃Or MoO₃9-19 wt%, NiO or CoO 5-10 wt%, Y-type molecular sieve 15-45 wt% and alumina 5-30 wt%.

10. The method according to 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 method according to claim 1, wherein the aromatic hydrocarbon separation device in the step c) adopts a furfural refining unit, and the operating conditions of an extraction part of the furfural refining unit are as follows: the pressure in the tower is 0.01-0.8 MPa, the temperature is 50-150 ℃, the mass ratio of the solvent is 1-8, and the circulating mass ratio is 0-0.6.

12. The method of claim 11, wherein the operating conditions are: the pressure in the tower is 0.02-0.1 MPa, the temperature is 60-110 ℃, the mass ratio of the solvent is 2-7, and the circulating mass ratio is 0.2-0.5.

13. The process of claim 1, wherein the reaction conditions for the conversion reactions in steps b), d and e) are: 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 ℃.

14. The method of claim 13, wherein the conversion reaction is carried out under reaction conditions of: the volume space velocity is 0.8-2.5 h^-1The hydrogen partial pressure is 6-10 MPa, the volume ratio of hydrogen to oil at the inlet is 400: 1-700: 1, and the reaction temperature is 380-420 ℃.

15. The method according to claim 1, wherein the mass conversion in step e) above the cut point in step a) is controlled to not more than 80%.