CN114426875B

CN114426875B - Method for producing low-carbon olefin and BTX by catalytic pyrolysis of crude oil

Info

Publication number: CN114426875B
Application number: CN202011187089.9A
Authority: CN
Inventors: 龚剑洪; 杨超; 魏晓丽
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: 2020-10-29
Filing date: 2020-10-29
Publication date: 2023-07-11
Anticipated expiration: 2040-10-29
Also published as: CN114426875A

Abstract

The present disclosure relates to a method for producing light olefins and light aromatics by catalytic cracking of crude oil, the method comprising: cutting desalted and dehydrated crude oil into light distillate and heavy distillate; carrying out first catalytic pyrolysis on light distillate oil and a first catalyst, and then carrying out gas-solid separation to obtain first oil gas and a first spent catalyst; or carrying out gas-solid separation after carrying out second catalytic pyrolysis on the light distillate oil and the first catalyst to obtain second oil gas and a second spent catalyst; carrying out gas-solid separation on the heavy distillate oil and the second catalyst after third catalytic cracking to obtain third oil gas and a third spent catalyst; performing first burning regeneration on the first to-be-regenerated catalyst or the second to-be-regenerated catalyst to obtain a first regenerant or a second regenerant respectively; carrying out second burning regeneration on the third spent catalyst; heat transfer between the first regenerator and the second regenerator is not mass transfer. The method can obviously improve the yield of the low-carbon olefin and the light aromatic hydrocarbon and improve the economical efficiency of the device.

Description

Method for producing low-carbon olefin and BTX by catalytic pyrolysis of crude oil

Technical Field

The application relates to petroleum refining and petrochemical processing, in particular to a method for producing low-carbon olefin and BTX by catalytic cracking of crude oil.

Background

The consumption rate of the finished oil in the market is continuously slowed down at present, the demand of basic organic raw materials such as low-carbon olefin, aromatic hydrocarbon and the like is still increased at a high speed, and chemical industry refineries are future development trends facing such situations. The configuration of the chemical refinery at present mainly comprises the following three types, namely, crude oil is directly fed into a steam cracking unit to produce chemical materials after pretreatment such as solvent deasphalting or hydrofining, but the mode is generally limited to light crude oil; secondly, after hydrocracking each fraction of crude oil, maximizing the generation of heavy naphtha, and then maximizing the production of aromatic hydrocarbon through a reforming unit; and thirdly, the light fraction of the crude oil enters a steam cracking unit, and the heavy fraction enters a catalytic cracking unit, so that the production of low-carbon olefin is maximized. All three modes are industrialized, and the yield of chemicals is between 35% and 55%. It can be seen that the configuration of the existing chemical refinery mainly depends on the combination of a plurality of core devices such as steam cracking, reforming, hydrofining, hydrocracking, catalytic cracking and the like. The catalytic cracking process has unique advantages in the aspects of production of chemical materials and raw material adaptability, and can simultaneously produce propylene, ethylene and BTX.

Chinese patent CN109370644a discloses a method for preparing low-carbon olefins and aromatic hydrocarbons by catalytic cracking of crude oil, the method divides crude oil into light and heavy components, the cutting point is between 150 ℃ and 300 ℃, the light fraction and the heavy fraction react in different reaction areas of the same reactor, aluminosilicate composed of silica and alumina is used as main components of the catalyst, and the aluminosilicate comprises alkali metal oxide, alkaline earth metal oxide, titanium oxide, iron oxide, vanadium oxide and nickel oxide. The method is a solution proposal for generating the low-carbon olefin by catalytic cracking of crude oil based on a dense-phase conveying bed reactor for generating the low-carbon olefin by catalytic cracking of heavy oil.

Chinese patent CN1315990 discloses a two-catalyst system coupling regeneration process. The method is characterized in that a special regenerator for regenerating a special catalyst in a novel fluidized catalytic reaction process is arranged beside a regenerator of a conventional catalytic cracking device, wherein the particle diameter of the special catalyst is more than 700 mu m, the conventional catalytic cracking catalyst and the special catalyst are separated under the action of gravity after regeneration, the special catalyst after high-temperature regeneration and a small part of conventional catalyst enter a secondary separator through a channel, air is introduced at the bottom of the secondary separator to fluidize the catalyst, and the special catalyst and the conventional catalyst are further separated under the action of gravity. According to different physical properties of special catalyst particles, the method introduces the excess heat of the conventional catalytic cracking device into the novel fluidized catalytic reaction process with insufficient heat to supplement heat.

Chinese patent CN102690682 discloses a catalytic cracking method and apparatus for producing propylene, in which heavy raw material and a first catalytic cracking catalyst using Y-type zeolite as main active component are contacted and reacted in a first riser reactor, light hydrocarbon and a second catalytic cracking catalyst using shape-selective zeolite with pore diameter smaller than 0.7nm as main active component are contacted and reacted in a second riser reactor, and the reacted oil gas and catalyst are introduced into a fluidized bed reactor connected in series with the second riser reactor to react. The steam stripping device of the catalytic cracking device is divided into two independent steam stripping areas by a partition board, one steam stripping area forms a reaction and steam stripping route with a combined reactor formed by a lifting pipe and a fluidized bed, and the other steam stripping area forms a corresponding other reaction and steam stripping route with the other lifting pipe. The catalytic cracking device provided by the invention has a simple structure, and can respectively react and regenerate by using two catalysts in one set of device.

The method relates to a method for preparing low-carbon olefin and aromatic hydrocarbon by taking crude oil as a raw material and developing novel catalytic materials, and simultaneously relates to a method for maximizing production of chemical materials by arranging different reaction areas and adopting respective special catalysts, but no special reactor structure for maximizing production of chemical materials of crude oil is adopted.

Disclosure of Invention

The aim of the present disclosure is to propose a reaction regeneration system suitable for processing crude oil for catalytic cracking to produce light olefins and BTX.

In order to achieve the above object, the present disclosure provides a method for producing light olefins and light aromatics by catalytic cracking of crude oil, the method comprising the steps of:

s1, cutting desalted and dehydrated crude oil into light distillate and heavy distillate; the cutting point of the cutting is any temperature between 100 ℃ and 400 ℃;

s2, introducing the light distillate and a first catalyst into a first downlink reactor, performing first catalytic pyrolysis to obtain a first catalytic pyrolysis material, and then performing gas-solid separation to obtain first reaction oil gas and a first spent catalyst; or introducing the light distillate and the first catalyst into a second uplink reactor for second catalytic pyrolysis to obtain a second catalytic pyrolysis material, and then performing gas-solid separation to obtain second reaction oil gas and a second spent catalyst;

s3, introducing the heavy distillate oil and the second catalyst into a third uplink reactor for third catalytic pyrolysis, and then performing gas-solid separation to obtain third reaction oil gas and a third spent catalyst;

s4, introducing the first to-be-regenerated catalyst or the second to-be-regenerated catalyst into a first regenerator to perform first burning regeneration to obtain a first regenerant or a second regenerant respectively; introducing the third spent catalyst into a second regenerator to perform second scorching regeneration; heat transfer between the first regenerator and the second regenerator is not mass transfer;

optionally, the first regenerator and the second regenerator are two independent regenerators; alternatively, the first regenerator and the second regenerator are each one of two separate parts separated by one regenerator.

Optionally, the first regenerator is disposed inside the second regenerator; alternatively, the first regenerator and the second regenerator are each one of two separate parts separated by a regenerator with a thermally conductive plate.

Optionally, the first catalyst comprises 10 to 50 wt% of a shape selective zeolite having an average pore size of less than 0.7nm, 0 to 25 wt% of a beta zeolite, 10 to 45 wt% of a clay, and 25 to 50 wt% of an inorganic oxide binder, based on the dry weight of the catalyst; the second catalyst comprises 20-40 wt% of a shape selective zeolite having an average pore size of less than 0.7nm, 5-25 wt% of a Y-zeolite, 10-45 wt% of a clay, and 25-50 wt% of an inorganic oxide binder.

Alternatively, the dense phase catalyst temperature of the first regenerator and the second regenerator is in the range 650 to 740 ℃, preferably 680 to 720 ℃.

Optionally, in the first downgoing reactor, the conditions of the first catalytic cracking include: the outlet temperature of the first downlink reactor is 640-720 ℃, and the gas-solid residence time is 0.3-2.0 seconds; in the second upgoing reactor, the conditions for the second catalytic cracking include: the outlet temperature of the second uplink reactor is 620-710 ℃, and the gas-solid residence time is 0.3-5 seconds; in the third upgoing reactor, the conditions for the third catalytic cracking include: the outlet temperature of the third uplink reactor is 530-650 ℃, and the gas-solid residence time is 0.5-8 seconds.

Preferably, in the first downgoing reactor, the conditions of the first catalytic cracking include: the outlet temperature of the first downlink reactor is 650-710 ℃, and the gas-solid residence time is 0.5-1.5 seconds; in the second upgoing reactor, the conditions for the second catalytic cracking include: the outlet temperature of the second uplink reactor is 640-690 ℃, and the gas-solid residence time is 0.5-3 seconds; in the third upgoing reactor, the conditions for the third catalytic cracking include: the outlet temperature of the third uplink reactor is 560-640 ℃, and the gas-solid residence time is 1-5 seconds.

Optionally, the first downflow reactor is a downflow pipe reactor with equal diameter or variable diameter; the second up-flow reactor and the third up-flow reactor are selected from one of equal-diameter or variable-diameter riser reactors, equal-diameter or variable-diameter riser reactors and fluidized bed composite reactors.

Optionally, the method further comprises: separating light olefin fraction from the reaction oil gas, and returning the light olefin fraction to the first downlink reactor or the second uplink reactor for reaction; the light olefin fraction is C4 fraction in the reaction oil gas and/or fraction in the reaction oil gas at 60-90 ℃.

Optionally, carrying out catalytic cracking on the light olefin fraction and the first catalyst after 0.2-1.0 seconds of the light olefin fraction; preferably, the light olefin fraction is catalytically cracked with the first catalyst after 0.4 to 0.8 seconds of the light fraction oil.

Optionally, the crude oil is one or a mixture of more of conventional mineral oil, coal liquefied oil, synthetic oil, oil sand oil, shale oil, compact oil and animal and vegetable oil.

Through the technical scheme, the method for producing the low-carbon olefin and the BTX by catalytic cracking of the crude oil can obviously improve the yield of the low-carbon olefin and the light aromatic hydrocarbon and improve the economy of the device.

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

Drawings

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

FIG. 1 is a schematic diagram of an apparatus for producing light olefins and light aromatics by catalytic cracking of crude oil in example 1.

FIG. 2 is a schematic diagram of an apparatus for producing light olefins and light aromatics by catalytic cracking of crude oil in example 2.

Description of the reference numerals

1. Downer reactor 41, heavy distillate feed nozzle

11. Light distillate feed nozzle 42, second regenerated catalyst transfer line

12. Light olefin feed nozzle 5, second stripper

13. Oil mixer 51, second spent catalyst transfer pipe

14. Oil separator 6 and settler

15. Downer reactor oil gas outlet 61 and uper reactor oil gas outlet

16. First regenerated catalyst transfer pipe 7, second regenerator

2. First stripper 8, first riser reactor

21. First spent catalyst transfer pipe 81, light fraction oil feed nozzle

3. First regenerator 82, light olefin feed nozzle

31. Regenerated flue gas conveying pipe 83 and first regenerated catalyst conveying pipe

4. Upgoing bed reactor 84, first oil and gas outlet

Detailed Description

The following describes specific embodiments of the present disclosure in detail. It should be understood that the detailed description and specific examples, while indicating and illustrating the disclosure, are not intended to limit the disclosure.

The present disclosure provides a method for producing light olefins and light aromatics by catalytic cracking of crude oil, the method comprising the steps of:

as is well known to those skilled in the art, crude oil has the characteristics of wide distillation range, wide carbon number distribution and complex hydrocarbon composition, whole crude oil is used as a catalytic cracking raw material, and the optimal reaction conditions and catalyst performances for producing light olefins and light aromatics in different fraction sections are greatly different. Therefore, the present disclosure provides a method for producing light olefins and BTX by catalytic cracking of crude oil according to the hydrocarbon composition characteristics and cracking reaction characteristics of different fractions of crude oil. The light distillate and the heavy distillate are reacted under the respective proper catalyst composition by the method on one hand, so that the low-carbon olefin and BTX can be produced maximally; on the other hand, the regenerator which can exchange heat but does not exchange substances can transfer the excessive heat in the heavy fraction oil cracking process to the light fraction oil cracking process, thereby achieving the heat balance of the light and heavy fraction oil cracking processes.

According to the present disclosure, the first regenerator and the second regenerator may be two independent regenerators; alternatively, the first regenerator and the second regenerator may each be one of two separate parts separated by one regenerator.

According to the present disclosure, the first regenerator may be disposed inside the second regenerator; alternatively, the first regenerator and the second regenerator may each be one of two independent parts separated by a regenerator with a heat-conducting plate.

According to the present disclosure, the first catalyst may include 10-50 wt% of a shape selective zeolite having an average pore size of less than 0.7nm, 0-25 wt% of a beta zeolite, 10-45 wt% of a clay, and 25-50 wt% of an inorganic oxide binder, based on the dry weight of the catalyst; the second catalyst may include 20-40 wt% of a shape selective zeolite having an average pore size of less than 0.7nm, 5-25 wt% of a Y-zeolite, 10-45 wt% of clay, and 25-50 wt% of an inorganic oxide binder.

According to the present disclosure, the catalyst dense phase temperature of the first regenerator and the second regenerator may be 650-740 ℃, preferably the catalyst dense phase temperature of the first regenerator and the second regenerator may be 680-720 ℃.

According to the disclosure, the light distillate of the disclosure is catalytically cracked in the first downlink reactor at a high temperature with a short residence time and with a special catalyst, so that both low-carbon olefins and BTX can be produced with high selectivity and methane production can be significantly reduced. Wherein, in the first downgoing reactor, the conditions of the first catalytic cracking may include: the outlet temperature of the first downlink reactor is 640-720 ℃, and the gas-solid residence time is 0.3-2.0 seconds; in the second upgoing reactor, the conditions for the second catalytic cracking include: the outlet temperature of the second uplink reactor is 620-710 ℃, and the gas-solid residence time is 0.3-5 seconds; in the third upgoing reactor, the conditions for the third catalytic cracking may include: the outlet temperature of the third uplink reactor is 530-650 ℃, and the gas-solid residence time is 0.5-8 seconds. As a preferred embodiment of the present disclosure, in the first downgoing reactor, the conditions of the first catalytic cracking may include: the outlet temperature of the first downlink reactor is 650-710 ℃, and the gas-solid residence time is 0.5-1.5 seconds; in the second upgoing reactor, the conditions for the second catalytic cracking include: the outlet temperature of the second uplink reactor is 640-690 ℃, and the gas-solid residence time is 0.5-3 seconds; in the third upgoing reactor, the conditions for the third catalytic cracking may include: the outlet temperature of the third uplink reactor is 560-640 ℃, and the gas-solid residence time is 1-5 seconds.

According to the present disclosure, the first downflow reactor may be an equal-diameter or variable-diameter downflow reactor; the second up-flow reactor and the third up-flow reactor may be selected from one of an equal-diameter or variable-diameter riser reactor, and a fluidized bed composite reactor.

According to the present disclosure, the method may further comprise: separating light olefin fraction from the reaction oil gas, and returning the light olefin fraction to the first downlink reactor or the second uplink reactor for reaction; the light olefin fraction is C4 fraction in the reaction oil gas and/or fraction in the reaction oil gas at 60-90 ℃. The light olefin fraction disclosed by the invention is contacted with the catalyst for reaction after the light distillate oil, so that on one hand, the light olefin fraction is further converted into low-carbon olefin, and on the other hand, the initial contact temperature of the light olefin fraction and the catalyst can be reduced, and thus, the dry gas and coke yield can be obviously reduced.

According to the present disclosure, the light olefin fraction may be subjected to catalytic cracking with the first catalyst after 0.2 to 1.0 seconds of the light fraction oil; preferably, the light olefin fraction is catalytically cracked with the first catalyst after 0.4-0.8 seconds of the light fraction oil.

According to the present disclosure, the crude oil may be one or a mixture of several of conventional mineral oil, coal liquefied oil, synthetic oil, oil sand oil, shale oil, dense oil and animal and vegetable oil.

In a specific embodiment of the disclosure, as shown in fig. 1, a hot first catalyst is conveyed to a downer reactor 1 through a first regenerated catalyst conveying pipe 16, light fraction oil is sprayed into an oil mixer 13 through a feeding nozzle 11 to contact with the first catalyst, the oil is mixed and then undergoes catalytic cracking reaction in the downer reactor 1, light olefin is sprayed into the downer reactor 1 through a light olefin feeding nozzle 12 to undergo catalytic cracking reaction with the oil mixture from the upper part, the reacted oil is subjected to catalyst and oil-gas separation in an oil-gas separator 14, the obtained first reaction oil-gas is introduced into a fractionation device through an oil-gas outlet 15 of the downer reactor, the spent catalyst enters the first stripper 2, the adsorbed hydrocarbon product is stripped, the spent catalyst is conveyed to the first regenerator 3 through a first spent catalyst conveying pipe 21 to undergo catalyst regeneration, and the regenerated catalyst is returned to the downer reactor 1 for repeated use. The hot second catalyst is introduced into the bottom of the upflow bed reactor 4 through a second regenerated catalyst conveying pipe 42, the catalyst is lifted upwards through a pre-lifting medium, heavy distillate oil is sprayed into the upflow bed reactor 4 through a heavy distillate oil feeding nozzle 41 to contact and react with an oil mixture from the bottom, the reaction product enters a settler 6, the catalyst is separated from oil and gas in the settler 6, the obtained third reaction oil gas enters a fractionation device through an oil and gas outlet 61 of the upflow bed reactor, the third spent catalyst enters a second stripper 5, adsorbed hydrocarbon products are stripped, the catalyst is conveyed to a second regenerator 7 through a conveying pipe 51 to be regenerated, and the regenerated catalyst is returned to the reactor for reuse. The regeneration flue gas enters the flue gas system through a regeneration flue gas conveying pipe 31. The second regenerator is located inside the first regenerator. The reaction oil gas is further separated by a fractionating device to obtain dry gas, C3, C4, light gasoline, heavy gasoline, diesel oil and slurry oil.

In one embodiment of the present disclosure, as shown in fig. 2, a hot first catalyst is introduced into the bottom of the first riser reactor 8 through a first regenerated catalyst transfer pipe 83, and the first catalyst is lifted upward by a pre-lift medium. Light distillate oil is sprayed into the first riser reactor 8 through the feeding nozzle 81, contacts with the first catalyst to carry out catalytic cracking reaction, light olefin is sprayed into the first riser reactor 8 through the light olefin feeding nozzle 82, contacts with an oil mixture from the lower part to react, the reacted oil is separated from oil and gas, the obtained second reaction oil gas is introduced into the fractionation device through the first oil and gas outlet 84, the spent catalyst enters the first stripper 2, adsorbed hydrocarbon products are stripped, the spent catalyst is sent to the first regenerator 3 through the first spent catalyst conveying pipe 21 to carry out catalyst regeneration, and the regenerated catalyst is returned to the first riser reactor 1 to be reused. The hot second catalyst is introduced into the bottom of the second riser reactor 4 through a second regenerated catalyst conveying pipe 42, the second catalyst is lifted upwards through a pre-lifting medium, heavy distillate is sprayed into the second riser reactor 4 through a heavy distillate feeding nozzle 41 to contact and react with an oil mixture from the bottom, the heavy distillate enters a settler 6 after reaction, the catalyst is separated from oil and gas in the settler 6, the reacted oil and gas enters a fractionation device through a second oil and gas outlet 61, the third spent catalyst enters a second stripper 5, adsorbed hydrocarbon products are stripped, the adsorbed hydrocarbon products are conveyed to a second regenerator 7 through a conveying pipe 51 to be regenerated, and the regenerated catalyst is returned to the reactor for reuse. The regeneration flue gas enters the flue gas system through a regeneration flue gas conveying pipe 31. The second regenerator is located inside the first regenerator. The reaction oil gas is further separated by a fractionating device to obtain dry gas, C3, C4, light gasoline, heavy gasoline, diesel oil and slurry oil.

The present disclosure is further illustrated in detail by the following examples. The starting materials used in the examples are all available commercially. Among them, the catalysts used in examples and comparative examples of the present disclosure include two catalysts, catalyst a and catalyst B, the properties of which are shown in table 1, and the main physicochemical properties of which are shown in table 1, after being thermally aged for 10 hours at 800 ℃ by saturated steam at a temperature before the catalysts are used. The properties of the raw materials used in the examples and comparative examples are shown in Table 2.

TABLE 1

Catalyst	Catalyst A	Catalyst B
			Chemical composition, percent
ZSP molecular sieve	35	30
			Beta molecular sieve	5	-
USY molecular sieve	-	10
			Clay	25	25
Inorganic oxide	35	35

TABLE 2

Project	Crude oilA
		Density (20 ℃ C.)/(g.cm) ^-3 )	0.864
Freezing point/°c	32
		Kinematic viscosity (50 ℃ C.)/(mm ² /s)	23.23
Residual carbon/%	3.18
		Wax content/%	32.1
Asphaltenes/%	0.2
		Fraction mass fraction/%of less than 250 DEG C	13.7
Fraction mass fraction/%of less than 350 DEG C	21.2

Example 1

Example 1 illustrates: the cut point of the light and heavy fractions of the processed crude oil is 350 ℃.

Two sets of medium-sized devices with continuous reaction-regeneration operation are adopted for the test, wherein one set of medium-sized device is a down-tube reactor, a high-temperature regenerated catalyst A at 700 ℃ is introduced into the top of the down-tube reactor through a regeneration inclined tube, preheated light fraction oil is atomized through steam and enters the down-tube reactor through a feed nozzle to contact with the hot regenerated catalyst A for catalytic cracking reaction, C4 and light gasoline enter the down-tube reactor through the feed nozzle at a position 600 mm below the light fraction oil nozzle under an atomized steam medium to contact with an oil mixture from the upper part for reaction, the reacted oil is subjected to cyclone separation to obtain reaction oil gas and a spent catalyst A, the reaction oil gas enters a subsequent product separation system, the spent catalyst A is introduced into a stripper for stripping and then enters the regenerator, and the regenerated catalyst A returns to the down-tube reactor for recycling. Another set of medium-sized apparatus is a riser reactor. Spraying heavy distillate oil into a riser reactor through a heavy distillate oil nozzle after atomizing the heavy distillate oil, contacting with a high-temperature regenerated catalyst B at 700 ℃ to perform catalytic cracking reaction, introducing the reaction oil into a settler to perform oil-liquid separation, and introducing the reaction oil gas into a product separation system to separate into dry gas, C3, C4, light gasoline, heavy gasoline, diesel oil and slurry oil. The spent catalyst B from the riser enters a stripper, hydrocarbon products adsorbed by the spent catalyst are stripped, and then enter a regenerator through a spent agent inclined tube, and are burnt and regenerated at 700 ℃ in contact with air. The regenerated catalyst B returns to the reactor for recycling through a regeneration inclined tube. The medium-sized device adopts electric heating to maintain the temperature of the reaction and regeneration system.

The main operating conditions and results are shown in Table 3.

Example 2

Example 2 illustrates: the cutting point of the light and heavy fractions of the processed crude oil is 260 ℃.

Two sets of medium-sized devices with continuous reaction-regeneration operation are adopted for the test, wherein one set of medium-sized device is a riser reactor, a high-temperature regenerated catalyst A at 700 ℃ is introduced into the bottom of the riser reactor through a regeneration inclined tube, preheated light distillate oil enters the riser reactor through a feeding nozzle to contact with the hot regenerated catalyst A for catalytic cracking reaction after being atomized by water vapor, carbon four and light gasoline enter the riser reactor through the feeding nozzle at a position 600 mm above the light distillate oil nozzle under an atomized water vapor medium to contact with an oil mixture from the lower part for reaction, the reacted oil is separated into reaction oil gas and spent catalyst A through a cyclone separator, the reaction oil gas enters a subsequent product separation system, the spent catalyst A enters a regenerator after being introduced into a stripper for stripping, and the regenerated catalyst A returns to the riser reactor for recycling. The other set of medium-sized device is also a riser reactor. Spraying heavy distillate oil into a riser reactor through a heavy distillate oil nozzle after atomizing the heavy distillate oil, contacting with a high-temperature regenerated catalyst B at 700 ℃ to perform catalytic cracking reaction, introducing the reaction oil into a settler to perform oil-liquid separation, and introducing the reaction oil gas into a product separation system to separate into dry gas, C3, C4, light gasoline, heavy gasoline, diesel oil and slurry oil. The spent catalyst B from the riser enters a stripper, hydrocarbon products adsorbed by the spent catalyst are stripped, and then enter a regenerator through a spent agent inclined tube, and are burnt and regenerated at 700 ℃ in contact with air. The regenerated catalyst B returns to the reactor for recycling through a regeneration inclined tube.

The medium-sized device adopts electric heating to maintain the temperature of the reaction and regeneration system.

The main operating conditions and results are shown in Table 3.

Comparative example 1

Comparative example 1 illustrates: under the same reaction conditions as in example 2, except that the upflow bed reactor used the same catalyst B as the riser reactor.

The reaction apparatus used was the same as in example 1, except that catalyst B was used in the downer reactor, using the same starting materials and the same main procedure as in example 1.

The main operating conditions and results are shown in Table 3.

TABLE 3 Table 3

As can be seen from table 3, the method for producing light olefins and BTX by catalytic cracking of crude oil provided by the present disclosure significantly improves the yields of light olefins and light aromatics and improves the economy of the apparatus.

The preferred embodiments of the present disclosure have been described in detail above, but the present disclosure is not limited to the specific details of the above embodiments, and various simple modifications may be made to the technical solutions of the present disclosure within the scope of the technical concept of the present disclosure, and all the simple modifications belong to the protection scope of the present disclosure.

In addition, the specific features described in the above embodiments may be combined in any suitable manner without contradiction. The various possible combinations are not described further in this disclosure in order to avoid unnecessary repetition.

Moreover, any combination between the various embodiments of the present disclosure is possible as long as it does not depart from the spirit of the present disclosure, which should also be construed as the disclosure of the present disclosure.

Claims

1. A method for producing light olefins and light aromatics by catalytic cracking of crude oil, comprising the following steps:

separating a light olefin fraction from the reaction oil gas, and returning the light olefin fraction to the first downlink reactor or the second uplink reactor for reaction;

the light olefin fraction is C4 fraction and light gasoline in reaction oil gas; carrying out catalytic cracking on the light olefin fraction and the first catalyst after 0.2-1.0 seconds of the light distillate oil;

the first catalyst comprises, on a dry catalyst basis, 10 to 50 wt% of a shape selective zeolite having an average pore size of less than 0.7nm, 0 to 25 wt% of a beta zeolite, 10 to 45 wt% of a clay, and 25 to 50 wt% of an inorganic oxide binder;

the second catalyst comprises 20-40 wt% of a shape selective zeolite having an average pore size of less than 0.7nm, 5-25 wt% of a Y-zeolite, 10-45 wt% of a clay, and 25-50 wt% of an inorganic oxide binder.

2. The method of claim 1, wherein the first regenerator and the second regenerator are two independent regenerators; alternatively, the first regenerator and the second regenerator are each one of two separate parts separated by one regenerator.

3. The method of claim 1, wherein the first regenerator is disposed inside the second regenerator; alternatively, the first regenerator and the second regenerator are each one of two separate parts separated by a regenerator with a thermally conductive plate.

4. The process of claim 1, wherein the catalyst dense phase temperature of the first regenerator and the second regenerator is 650-740 ℃.

5. The process of claim 4, wherein the catalyst dense phase temperature of the first regenerator and the second regenerator is 680-720 ℃.

6. The method of claim 1, wherein,

in the first downgoing reactor, the conditions of the first catalytic cracking include: the outlet temperature of the first downlink reactor is 640-720 ℃, and the gas-solid residence time is 0.3-2.0 seconds;

in the second upgoing reactor, the second catalytic cracking conditions include: the outlet temperature of the second uplink reactor is 620-710 ℃, and the gas-solid residence time is 0.3-5 seconds;

in the third upgoing reactor, the third catalytic cracking conditions include: the outlet temperature of the third uplink reactor is 530-650 ℃, and the gas-solid residence time is 0.5-8 seconds.

7. The method of claim 6, wherein,

in the first downgoing reactor, the conditions of the first catalytic cracking include: the outlet temperature of the first downlink reactor is 650-710 ℃, and the gas-solid residence time is 0.5-1.5 seconds;

in the second upgoing reactor, the second catalytic cracking conditions include: the outlet temperature of the second uplink reactor is 640-690 ℃, and the gas-solid residence time is 0.5-3 seconds;

in the third upgoing reactor, the third catalytic cracking conditions include: the outlet temperature of the third uplink reactor is 560-640 ℃, and the gas-solid residence time is 1-5 seconds.

8. The method of claim 1, wherein the first downer reactor is an equal-diameter or variable-diameter downer reactor;

the second up-flow reactor and the third up-flow reactor are selected from one of equal-diameter or variable-diameter riser reactors, equal-diameter or variable-diameter riser reactors and fluidized bed composite reactors.

9. The process of claim 1, wherein the light olefin fraction is catalytically cracked with the first catalyst 0.4-0.8 seconds after the light distillate.