CN110540869B

CN110540869B - A method of catalytic cracking

Info

Publication number: CN110540869B
Application number: CN201810524642.XA
Authority: CN
Inventors: 杨超; 朱根权; 谢朝钢
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2018-05-28
Filing date: 2018-05-28
Publication date: 2021-08-06
Anticipated expiration: 2038-05-28
Also published as: CN110540869A

Abstract

The present invention relates to a method for catalytic cracking. The method comprises: (1) separating whole crude oil fractions to obtain light distillate oil, middle distillate oil and heavy distillate oil; (2) separating the obtained heavy distillate oil; The oil is subjected to the first catalytic cracking reaction to obtain the first reaction product and the first catalyst to be produced; (3), the obtained light distillate oil is subjected to the second catalytic cracking reaction to obtain the second reaction product and the semi-to-be-generated catalyst; (4) ), the obtained second reaction product and semi-to-be-grown catalyst are introduced into a fluidized bed reactor to carry out a third catalytic cracking reaction together with middle distillate oil and catalytically cracked gasoline to obtain a third reaction product and a second to-be-grown catalyst. The method provided by the invention fully considers the cracking characteristics of crude oil of different fractions, and can significantly improve the yield of low-carbon olefins in the catalytic cracking process and improve the economic benefit of the catalytic cracking device through zone reaction control and heat coupling.

Description

Catalytic cracking method

Technical Field

The present invention relates to a catalytic cracking process.

Background

From the production conditions of gasoline and diesel oil in China in recent years, the yield of gasoline and diesel oil in China, particularly the gasoline yield, keeps continuously increasing, but the apparent consumption of gasoline falls back from 2016, and the apparent consumption of diesel oil is continuously reduced. In 2016, the gasoline export of China is increased by 64.4 percent in the same proportion, and the diesel oil export is increased by 115 percent in the same proportion. The surplus of the production capacity and the increased competition of the finished oil market are the main problems in the domestic oil refining industry. On the other hand, the domestic shortage of olefin, aromatic hydrocarbon and other chemical raw materials is still large, and the transformation from fuel type to chemical type in oil refining enterprises is a great trend.

Catalytic cracking is used as an important crude oil secondary processing technology, and has irreplaceable status in the aspects of producing light oil products and low-carbon olefins by using the characteristics of wide raw material adaptability, high heavy oil conversion rate, flexible product scheme and the like. In view of the current development and development trend of catalytic cracking technology for producing chemical raw materials in recent years, research is mainly carried out on four aspects of improving reaction severity, using a catalyst or an auxiliary agent containing a shape-selective molecular sieve, using a novel reactor structure, recycling a fraction rich in a propylene precursor and the like.

Chinese patent CN101531923A discloses a catalytic conversion method for preparing propylene and high octane gasoline, which considers oil slurry, diesel oil, gasoline, and hydrocarbons with 4-8 carbon atoms as raw materials which are difficult to crack, and vacuum gas oil, atmospheric gas oil, coker gas oil, deasphalted oil, vacuum residual oil, atmospheric residual oil, and hydrogenated heavy oil as raw materials which are easy to crack. The method contacts the raw material difficult to crack with the thermal regeneration catalytic cracking catalyst, and the reaction temperature is 600-750 ℃, the weight hourly space velocity is 100-800h^-1The cracking reaction is carried out under the condition of (1), the reactant flow is mixed with the raw oil easy to crack, and the cracking reaction is carried out under the conditions of the reaction temperature of 450-620 ℃ and the weight hourly space velocity of 0.1-100. The method can improve the yield and selectivity of propylene.

Chinese patent CN102899078A discloses a catalytic cracking method for producing propylene, which is based on a combined reactor composed of double risers and a fluidized bed, and comprises introducing heavy raw oil and a first catalyst into a first riser reactor for reaction, and separating the oil and then feeding the oil into a separation system. Introducing the cracked heavy oil into a second riser reactor to contact and react with the catalyst introduced into the second riser reactor, introducing light hydrocarbon into the second riser reactor to contact with a mixture formed by the contact and reaction of the cracked heavy oil and a second strand of cracking catalyst, wherein the light hydrocarbon comprises C4 hydrocarbon or gasoline fraction obtained by a product separation system. And then introducing the oil gas reacted by the second riser reactor and a catalyst into the fluidized bed reactor for reaction. Through the optimization of the process scheme, the proper catalyst is prepared, the selective conversion is carried out on different feeds, and the yield of propylene and butylene is higher.

Chinese patent CN103666551A discloses a catalytic processing method and device for high-temperature Fischer-Tropsch synthetic oil, which fully considers the distillation range distribution and divides the Fischer-Tropsch synthetic oil into three fractions, namely gaseous hydrocarbon, high-temperature condensate and low-temperature condensate, the method comprises the steps of enabling the gaseous hydrocarbon and the high-temperature condensate to enter a first riser reactor for catalytic conversion, enabling low condensate and recycle cracking light gasoline fraction to enter a combined bed reactor for conversion, enabling a catalyst introduced into a second riser reactor to be a regenerated catalyst from a regenerator and a spent catalyst from a stripper or a mixture of the regenerated catalyst and the spent catalyst, and constructing a processing route for the high-temperature Fischer-Tropsch synthetic oil, wherein the yield of processed propylene is high.

Chinese patent CN102533322A discloses a method for producing propylene by Fischer-Tropsch synthetic oil catalytic cracking, in which a material flow rich in small molecular olefins and a Fischer-Tropsch synthetic oil raw material are mixed and injected into a reactor, and not only a heavy Fischer-Tropsch synthetic fraction but also a light Fischer-Tropsch synthetic oil fraction can be processed. Under the same reaction conditions, when the method is used for processing the Fischer-Tropsch synthetic oil, the yield of the propylene is improved by 6.74 percent.

The method does a great deal of work in the aspect of process design of catalytic cracking for producing more low-carbon olefins, achieves a certain effect, and has certain consideration on processing of the Fischer-Tropsch synthetic oil whole fraction raw material, but the crude oil whole fraction and the Fischer-Tropsch synthetic oil are obviously different in hydrocarbon composition and catalytic cracking properties, so that further research is needed on how to process the crude oil whole fraction and how to optimally produce the low-carbon olefins.

Disclosure of Invention

The invention aims to provide a catalytic cracking method, which has high yield of low-carbon olefin.

In order to achieve the above object, the present invention provides a catalytic cracking process comprising:

(1) separating the whole fraction of the crude oil to obtain light distillate oil, medium distillate oil and heavy distillate oil; wherein the crude oil whole fraction is at least one selected from mineral oil, coal liquefaction oil, synthetic oil, oil sand oil, shale oil, compact oil and animal and vegetable oil; the initial boiling point of the light distillate is in the range of 15-100 ℃, the cutting points of the light distillate and the medium distillate are in the range of 180-240 ℃, and the cutting points of the medium distillate and the heavy distillate are in the range of 380-480 ℃;

(2) introducing the obtained heavy distillate oil into the lower part of a first riser reactor to contact with a first catalytic cracking catalyst from the bottom of the first riser reactor and carrying out a first catalytic cracking reaction to obtain a first reaction product and a first catalyst to be generated;

(3) introducing the obtained light distillate oil into a second riser reactor to contact with a second catalytic cracking catalyst and carry out a second catalytic cracking reaction to obtain a second reaction product and a semi-spent catalyst;

(4) introducing the obtained second reaction product and the semi-spent catalyst into the fluidized bed reactor to carry out a third catalytic cracking reaction together with the medium distillate oil and the catalytic cracking gasoline to obtain a third reaction product and a second spent catalyst; wherein the distillation range of the catalytic cracking gasoline is between 30 and 240 ℃;

(5) feeding the obtained first spent catalyst and the second spent catalyst into a regenerator for regeneration, wherein the obtained regenerated catalyst is used as the first catalytic cracking catalyst and the second catalytic cracking catalyst;

(6) and separating the first reaction product and the third reaction product to obtain a gas product, a gasoline product, a diesel oil product and a heavy oil product.

Optionally, the distillation range of the catalytically cracked gasoline in the step (4) is between 30 and 120 ℃.

Optionally, the method further includes: introducing at least a portion of the gasoline product obtained in step (6) into the fluidized bed reactor as the catalytically cracked gasoline.

Optionally, the crude oil whole fraction has a UOP K value greater than 12.2.

Optionally, the initial cut point of the light distillate is in the range of 25-80 ℃, the cut points of the light distillate and the medium distillate are in the range of 200-240 ℃, and the cut points of the medium distillate and the heavy distillate are in the range of 400-450 ℃.

Optionally, the weight ratio of the heavy distillate to the whole crude oil fraction is more than 30 wt%, and/or the 95 vol% distillation point of the medium distillate is in the range of 380-430 ℃.

Optionally, the method further includes: if the 95 volume percent distillation point of the medium distillate oil is T1 ℃, the outlet temperature of the first riser reactor is T2 ℃, and the outlet temperature of the fluidized bed reactor is T3 ℃, the outlet temperature of the first riser reactor is adjusted to be T2+ T/10 x a ℃ and the outlet temperature of the fluidized bed reactor is adjusted to be T3+ T/10 x b ℃ every time the 95 volume percent distillation point T of the medium distillate oil is increased, wherein a is any value from 0.5 to 2, and b is any value from 0.5 to 3.

Optionally, the conditions of the first catalytic cracking reaction include: the reaction temperature is 480-560 ℃, the oil gas retention time is 0.5-5 seconds, and the weight ratio of the weight of the first catalytic cracking catalyst to the weight of the heavy distillate oil is 4-15.

Optionally, the conditions of the second catalytic cracking reaction include: the reaction temperature is 600-670 ℃, the oil gas residence time is 0.5-5 seconds, and the weight ratio of the weight of the second catalytic cracking catalyst to the weight of the light distillate oil is 6-40.

Optionally, the conditions of the third catalytic cracking reaction include: the reaction temperature is 560 ℃ and 650 ℃, and the weight hourly space velocity is 2-30 h^-1The feed weight ratio of the medium distillate oil to the catalytic cracking gasoline is 1: (0.2-2).

Optionally, the first catalytic cracking catalyst and the second catalytic cracking catalyst each independently comprise a carrier and an active component, and the active component is at least one selected from the group consisting of Y or HY type zeolite with or without rare earth, ultrastable Y type zeolite with or without rare earth, ZSM-5 series zeolite, high silica zeolite with pentasil structure and beta zeolite.

Compared with the prior art, the method provided by the invention fully considers the cracking characteristics of different fractions of crude oil, and can remarkably improve the yield of low-carbon olefin in the catalytic cracking process and improve the economic benefit of a catalytic cracking device through zone reaction control and heat coupling.

Additional features and advantages of the invention will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

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

Description of the reference numerals

1 first riser reactor 11 transfer pipe 12 flow control valve

13 feeding nozzle 14 gas-solid quick separation device

2 second riser reactor 21 transfer pipe 22 flow control valve

23 feed nozzle 24 outlet distributor

3 fluidized bed reactor 31 feed nozzle 32 feed nozzle

33 baffle plate

4-settler 41 primary cyclone 42 secondary cyclone

5 stripper 51 baffle 52 duct

53 flow control valve

6 regenerator

7 gap

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

The invention provides a catalytic cracking method, which comprises the following steps:

The crude oil whole fraction refers to the extracted oil product which is only cut simply, and the processes such as atmospheric and vacuum distillation, hydrotreating, catalytic cracking and the like are not performed. The UOP K value of the whole fraction of the crude oil is preferably greater than 12.2, which is well known to those skilled in the art and may be referred to as the crude oil figure of merit or watson K value, as a function of the average boiling point and relative density of the oil.

According to the invention, the catalytically cracked gasoline comes from a catalytic cracking unit, and the distillation range of the catalytically cracked gasoline in the step (4) is preferably between 30 and 120 ℃. In order to further improve the yield of the low-carbon olefin, the method can further comprise the following steps: introducing at least a portion of the gasoline product obtained in step (6) into the fluidized bed reactor as the catalytically cracked gasoline.

In the present invention, the initial cut point of the light fraction is preferably in the range of 25-80 ℃, the cut points of the light fraction and the medium fraction are preferably in the range of 200-240 ℃, and more preferably in the range of 200-220 ℃, and the cut points of the medium fraction and the heavy fraction are preferably in the range of 400-450 ℃.

In the present invention, the weight ratio of the heavy fraction to the whole crude oil fraction is preferably more than 30 wt%, generally less than 85 wt%, and/or the 95 vol% cut point of the middle fraction is preferably in the range of 380-430 ℃, and the 95 vol% cut point of the middle fraction is determined by the ASTM D86 standard method. The reaction temperature of the first riser reactor and the reaction temperature of the fluidized bed reactor have a great relationship with the 95 volume percent distillation point of the medium distillate oil. The 95 vol% distillation point of the medium distillate is raised, and a part of the crackable components are transferred from the reaction in the first riser reactor to the fluidized bed reactor for producing propylene. The 95 vol% distillate point of the middle distillate oil is increased and the crackable component of the first riser reactor is reduced, requiring increased reaction severity. The reaction severity of the fluidized-bed reactor should also increase correspondingly, since the cracking capacity of the cracking component decreases. However, the 95 vol% cut point of the middle distillate cannot be too high, which would result in a large amount of dry gas and coke formation in the high severity fluidized bed reactor.

In one embodiment, the method further comprises: if the 95 volume percent distillation point of the medium distillate oil is T1 ℃, the outlet temperature of the first riser reactor is T2 ℃, and the outlet temperature of the fluidized bed reactor is T3 ℃, the outlet temperature of the first riser reactor is adjusted to be T2+ T/10 x a ℃ and the outlet temperature of the fluidized bed reactor is adjusted to be T3+ T/10 x b ℃ every time the 95 volume percent distillation point T of the medium distillate oil is increased, wherein a is any value from 0.5 to 2, and b is any value from 0.5 to 3. For example, if the 95 vol% cut point of the middle distillate increases by 50 ℃, the outlet temperature of the first riser reactor increases by 2.5 to 10 ℃ and the outlet temperature of the fluidized bed reactor increases by 2.5 to 15 ℃.

According to the invention, the first riser reactor is heavyDistillate oil is used as raw material, and proper reaction conditions are adopted to produce propylene and propylene precursors to the maximum extent. The second riser reactor is a place for pre-cracking light distillate oil and maximally producing propylene foreigners, and the fluidized bed reactor is a place for maximally producing propylene from medium distillate oil and propylene foreigners. The catalytic cracking gasoline is rich in a large amount of olefin, and is injected into a fluidized bed to be contacted with a catalyst with carbon, so that the propylene selectivity can be improved. The conditions of the first catalytic cracking reaction may include: the reaction temperature (outlet temperature) is 480-. The conditions of the second catalytic cracking reaction may include: the reaction temperature (outlet temperature) is 600-670 ℃, the oil gas retention time is 0.5-5 seconds, and the weight ratio of the weight of the second catalytic cracking catalyst to the weight of the light distillate oil is 6-40. The conditions of the third catalytic cracking reaction may include: the reaction temperature (outlet temperature) is 560 ℃ and 650 ℃, and the weight hourly space velocity is 2-30 h^-1The feed weight ratio of the medium distillate oil to the catalytic cracking gasoline is 1: (0.2-2).

The catalytic cracking catalyst according to the present invention is well known to those skilled in the art, for example, the first catalytic cracking catalyst and the second catalytic cracking catalyst may each independently comprise a support and an active component, the active component being at least one selected from the group consisting of Y or HY type zeolite with or without rare earth, ultrastable Y type zeolite with or without rare earth, ZSM-5 series zeolite, high silica zeolite having a pentasil structure and beta zeolite, and those skilled in the art may also adopt catalysts of other compositions.

The following further describes embodiments of the present invention with reference to the accompanying drawings.

As shown in fig. 1, the regenerated catalyst is transferred to the first riser reactor 1 through a transfer pipe 11. The heavy distillate oil is sprayed into the first riser reactor 1 through the feeding nozzle 13, contacts with the regenerated catalyst and carries out a first catalytic cracking reaction to form a first oil mixture. The first oil agent mixture is separated by a gas-solid rapid separation device 14, the separated first catalyst to be generated enters a stripper 5, and the separated first reaction product flow is introduced into a fractionation device. The light distillate oil is sprayed into the second riser reactor 2 through the feeding nozzle 23, contacts with the hot regenerated catalyst from the conveying pipe 21 and carries out a second catalytic cracking reaction, and the amount of the catalyst conveyed to the second riser reactor 2 by the regenerated catalyst is adjusted through the flow control valve 22. Oil gas and catalyst reacted in the second riser reactor 2 are introduced into the fluidized bed reactor 3 through the outlet distributor 24 and the baffle 33, medium distillate oil and catalytic cracking gasoline are respectively sprayed into the fluidized bed reactor 3 through the feeding nozzle 31 and the feeding nozzle 32, are contacted with an oil mixture from the second riser reactor 2 and are subjected to a third catalytic cracking reaction, enter the settler 4 through the outlet of the fluidized bed reactor 3 after reacting in the fluidized bed reactor 3, are separated from the oil gas in the settler 4, spent catalyst enters the stripper 5 through the gap 7 and is subjected to oil separation through the baffle 51, and the oil gas further separates catalyst fine powder carried in the oil gas through the primary cyclone separator 41 and the secondary cyclone separator 42 and enters the fractionating device to be further separated to obtain gas, gasoline, diesel oil and heavy oil. Gas oil gas is introduced into the settler 4 through the interspace 7. The spent catalyst is stripped in a stripper 5 to obtain adsorbed hydrocarbon products, the hydrocarbon products are sent to a regenerator 6 for regeneration through a conveying pipe 52 and a flow control valve 53, and the regenerated hot catalyst returns to the two riser reactors through a pipeline 21 and a pipeline 11 respectively for reuse.

The process according to the invention is further illustrated by the following examples, without the invention being restricted thereby.

The catalytic cracking catalysts used in the examples and comparative examples were industrially produced by the Qilu Branch of catalyst, of petrochemical Co., Ltd., China, under the trade name of MMC-2. The catalyst contains ultrastable Y-type zeolite and ZSP zeolite with average pore diameter less than 0.7 nm, and is hydrothermally aged for 14 hr at 800 deg.C before use, and its main physicochemical properties are shown in Table 1. The properties of the whole crude oil fractions used in the examples and comparative examples are shown in Table 2.

Example 1

Separating the whole fraction of the crude oil into heavy distillate oil, medium distillate oil and light distillate oil, wherein the initial boiling point of the light distillate oil is 70 ℃, the cutting point of the light distillate oil and the medium distillate oil is 200 ℃, the cutting point of the medium distillate oil and the heavy distillate oil is 400 ℃, the weight ratio of the heavy distillate oil to the whole fraction of the crude oil is 45 weight percent, and the 95 volume percent of the distillation point of the medium distillate oil is 380 ℃.

The test was carried out in a medium riser catalytic cracking unit. As shown in fig. 1, the medium-sized apparatus has a first riser reactor 1 with an inner diameter of 16 mm and a length of 3800 mm, a second riser reactor 2 with an inner diameter of 16 mm and a length of 3200 mm, an outlet of the second riser reactor 2 connected to a dense-phase fluidized bed reactor 3 with an inner diameter of 64 mm and a height of 600 mm. The high-temperature regenerated catalyst with the temperature of 700 ℃ is respectively introduced into the bottoms of the first riser reactor 1 and the second riser reactor 2 from the regenerator through a regeneration inclined pipe and flows upwards under the action of pre-lifting steam. After being mixed with atomized water vapor, heavy distillate oil enters a first riser reactor 1 through a feeding nozzle 13 to contact with a hot regenerant to carry out a first catalytic cracking reaction, a mixture of a first reaction product and a first catalyst to be regenerated ascends along the first riser reactor 1 to pass through a quick separation device at an outlet to carry out gas-solid separation, and first reaction oil gas is introduced into a settler and then introduced into a product separation system to be separated. The light distillate oil enters the lower part of a second riser reactor 2 through a feeding nozzle 23 under an atomized steam medium to contact with a hot regenerant to carry out a second catalytic cracking reaction, a mixture of a second reaction product and a semi-spent catalyst ascends along the second riser reactor 2 and enters a fluidized bed reactor 3 through an outlet of the second riser reactor 2, and the medium distillate oil and catalytic cracking gasoline (with the distillation range of 30-120 ℃) are mixed according to the weight ratio of 1: 0.3 weight ratio of the first catalytic cracking reaction product to the second catalytic cracking reaction product, and introducing the second spent catalyst into a settler for oil separation after the first catalytic cracking reaction product and the second spent catalyst react in the fluidized bed reactor 3, introducing the obtained third reaction product into a product separation system for separation into gas and liquid products, and returning the obtained catalytic cracking gasoline to the fluidized bed reactor 3 for recycling. The first spent catalyst containing coke from the first riser reactor 1 and the second spent catalyst containing coke from the fluidized bed reactor 3 enter the same stripper 5, and the stripping steam is used for stripping hydrocarbon products adsorbed on the spent catalyst and then enters a settler through the fluidized bed reactor for gas-solid separation. The spent agent after steam stripping enters a regenerator through a spent agent inclined pipe, contacts with air and is burned and regenerated at high temperature of 700 ℃. The regenerated catalyst returns to the riser reactor through the regenerated inclined tube for recycling. The medium-sized devices use electrical heating to maintain the temperature of the reaction-regeneration system.

The main operating conditions and results are listed in table 3.

Example 2

Example 2 is essentially the same as example 1 except that the 95 vol% cut point of the middle distillate is 430 c, i.e. the cut point of the middle and heavy distillates is adjusted to 450 c, the weight ratio of the heavy distillate to the whole crude oil is 40 wt%, the outlet temperature of the first riser reactor 1 is increased by 5 c and the outlet temperature of the fluidized bed reactor is increased by 10 c.

The main operating conditions and results are listed in table 3.

Example 3

Example 3 is essentially the same as example 1 except that the 95 vol% cut point of the middle distillate is 430 c, i.e., the cut points of the middle and heavy distillates are adjusted to 450 c, and the weight ratio of the heavy distillate to the whole crude oil fraction is 40 wt%.

The main operating conditions and results are listed in table 3.

Comparative example 1

Comparative example 1 is essentially the same as example 1 except that both the middle distillate and the light distillate enter the second riser reactor 2 through the feed nozzle 23.

The main operating conditions and results are listed in table 3.

Comparative example 2

Comparative example 2 is essentially the same as example 1 except that both the catalytically cracked gasoline and the light distillate are fed to the second riser reactor 2 through feed nozzle 23.

The main operating conditions and results are listed in table 3.

Comparative example 3

Comparative example 3 is substantially the same as example 1 except that the crude oil whole fraction was not cut, but the flow rates and positions of the crude oil whole fraction into the first riser reactor 1, the second riser reactor 2 and the fluidized bed reactor 3 were the same as those of example 1, and the catalytic cracked gasoline was fed into the fluidized bed reactor 3.

The main operating conditions and results are listed in table 3.

Comparative example 4

Comparative example 3 is essentially the same as example 1 except that the catalytically cracked gasoline is not injected into the fluidized bed reactor, i.e., the catalytically cracked gasoline is not subjected to a recycle.

The main operating conditions and results are listed in table 3.

As can be seen from the data in Table 3, the method provided by the invention can obviously improve the yield of low-carbon olefins such as propylene and the like, and can improve the economic benefit of a catalytic cracking unit.

The preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.

It should be noted that the various technical features described in the above embodiments can be combined in any suitable manner without contradiction, and the invention is not described in any way for the possible combinations in order to avoid unnecessary repetition.

In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the content of the present invention as long as it does not depart from the gist of the present invention.

TABLE 1

Catalyst and process for preparing same	Equilibrium catalyst
		Physical Properties
Specific surface area/m²G^-1	143
		Pore volume/cm^-3G^-1	0.186
Apparent density g.cm^-3	0.85
		Chemical composition/weight%
Al₂O₃	54.8
		SiO₂	39.9
RE₂O₃	0.44
		Particle size distribution/weight%
0-20 micron	1.6
		0-40 micron	15.0
0-80 micron	58.1
		0-110 micron	76.6
0-149 mu m	92.5
		Microreflective activity/weight%	63

TABLE 2

Item	Crude oil whole fraction
		Density (20 deg.C)/g.cm^-3	0.8634
Freezing point/. degree.C	40
		Carbon residue/weight%	3.21
Element composition/weight%
		C	85.67
H	13.36
		Crude oil composition/weight%
Glue	8.8
		Asphaltenes	0.1
Distillation range/. degree.C
		HK	70
5% by volume	153
		10% by volume	225
30% by volume	381
		50% by volume	458
59.9% by volume	581
		UOP K value	12.6

TABLE 3

Claims

1. a method for catalytic cracking, the method comprising:

(1), the crude oil whole cut is separated to obtain light distillate oil, medium distillate oil and heavy distillate oil; wherein, the crude oil whole cut is selected from mineral oil, coal liquefied oil, synthetic oil, oil sand oil , at least one of shale oil, tight oil and animal and vegetable oil; the initial boiling point of the light distillate oil is in the range of 15-100 ° C, the cutting point of the light distillate oil and the middle distillate oil In the range of 180-240°C, the cut points of the middle distillate and heavy distillate oils are in the range of 380-480°C;

(2), the obtained heavy distillate oil is introduced into the first riser reactor lower part to contact with the first catalytic cracking catalyst from the first riser reactor bottom and carry out the first catalytic cracking reaction to obtain the first reaction product and the first catalytic cracking reaction. waiting catalyst;

(3), the gained light distillate oil is introduced into the second riser reactor to contact with the second catalytic cracking catalyst and carry out the second catalytic cracking reaction to obtain the second reaction product and the semi-to-be-generated catalyst;

(4), the gained second reaction product and semi-to-be-generated catalyst are introduced into fluidized bed reactor and carry out the 3rd catalytic cracking reaction together with middle distillate oil and catalytically cracked gasoline, obtain the 3rd reaction product and the second to-be-generated catalyst; Wherein, the distillation range of the catalytically cracked gasoline is between 30-240°C;

(5), the obtained first catalyst and the second catalyst are sent into the regenerator for regeneration, and the obtained regeneration catalyst is used as the first catalytic cracking catalyst and the second catalytic cracking catalyst;

(6), the obtained first reaction product and the third reaction product are carried out product separation, obtain gas product, gasoline product, diesel oil product and heavy oil product,

Wherein, if the 95 vol% distillation point of the middle distillate oil is T1°C, the outlet temperature of the first riser reactor is T2°C, and the outlet temperature of the fluidized bed reactor is T3°C, each increase in the The 95 vol% distillation point of the middle distillate oil is t°C, the outlet temperature of the first riser reactor is adjusted to T2+t/10×a°C, and the outlet temperature of the fluidized bed reactor is adjusted to T3+t/10×b °C, wherein a is any value from 0.5 to 2, and b is any value from 0.5 to 3.

2 . The method according to claim 1 , wherein the distillation range of the catalytically cracked gasoline in step (4) is between 30-120° C. 3 .

3. The method of claim 1 or 2, further comprising: introducing at least a portion of the gasoline product obtained in step (6) into the fluidized bed reactor as the catalytically cracked gasoline.

4. The method of claim 1, wherein the crude oil whole fraction has a UOP K value greater than 12.2.

5. The method according to claim 1, wherein the initial boiling point of the light distillate oil is in the range of 25-80°C, and the cutting point of the light distillate oil and the middle distillate oil is 200-240°C Within the range of °C, the cut points of the middle distillate oil and heavy distillate oil are in the range of 400-450 °C.

6. The method according to claim 1 or 5, wherein the weight ratio of the heavy distillate oil to the total crude oil fraction is greater than 30% by weight, and/or the 95% by volume distillation point of the middle distillate oil is at 380-430°C range.

7. The method according to claim 1, wherein the conditions of the first catalytic cracking reaction include: the reaction temperature is 480-560° C., the oil and gas residence time is 0.5-5 seconds, the weight of the first catalytic cracking catalyst is the same as that of the first catalytic cracking catalyst. The weight ratio of the heavy distillate is 4-15.

8. The method according to claim 1, wherein the conditions for the second catalytic cracking reaction include: the reaction temperature is 600-670° C., the oil and gas residence time is 0.5-5 seconds, the weight of the second catalytic cracking catalyst is equal to the light weight The weight ratio of high quality distillates is 6-40.

9 . The method according to claim 1 , wherein the conditions of the third catalytic cracking reaction include: a reaction temperature of 560-650° C., a weight hourly space velocity of 2-30 hours ⁻¹ , the middle distillate oil and the The feed weight ratio of catalytically cracked gasoline is 1:(0.2-2).

10. The method of claim 1, wherein the first catalytic cracking catalyst and the second catalytic cracking catalyst each independently comprise a support and an active component selected from rare earth-containing or non-rare earth-containing components At least one of Y or HY type zeolite, ultrastable Y type zeolite with or without rare earth, ZSM-5 series zeolite, high silica zeolite with five-membered ring structure and beta zeolite.