CN116601268B

CN116601268B - Method and apparatus for catalytic cracking of hydrocarbon feedstock oil to produce low-carbon olefins and BTX

Info

Publication number: CN116601268B
Application number: CN202180074180.6A
Authority: CN
Inventors: 龚剑洪; 汪燮卿; 杨超; 魏晓丽; 朱根权; 马文明; 陈昀
Original assignee: Sinopec Petrochemical Research Institute Co ltd; China Petroleum and Chemical Corp
Current assignee: Sinopec Petrochemical Research Institute Co ltd; China Petroleum and Chemical Corp
Priority date: 2020-10-29
Filing date: 2021-10-29
Publication date: 2026-04-03
Anticipated expiration: 2041-10-29
Also published as: WO2022089575A1; CN114426877B; KR20230093312A; CN116601268A; EP4219664A1; EP4219664B1; US20230392087A1; CN114426877A; TWI899361B; TW202216969A; EP4219664A4

Abstract

A method and apparatus for producing low-carbon olefins and BTX by catalytic cracking of hydrocarbon-containing feedstock oil. The method includes: cutting the hydrocarbon-containing feedstock oil into light distillate oil and heavy distillate oil; introducing the light distillate oil and a first catalyst stream into a downflow reactor for catalytic cracking to obtain a first catalytic cracked product; performing gas-solid separation on the first catalytic cracked product to obtain a first reactive oil-gas and a first precursor catalyst; or, feeding the first catalytic cracked product into a fluidized bed reactor for catalytic cracking, followed by gas-solid separation to obtain a second reactive oil-gas and a second precursor catalyst; introducing a continuous catalyst, heavy distillate oil, and a second catalyst stream into an upflow reactor for catalytic cracking, followed by gas-solid separation to obtain a third oil-gas and a third precursor catalyst; separating low-carbon olefins and light aromatics from the reactive oil-gas, and separating the light olefin fraction, returning the light olefin fraction to the fluidized bed reactor or the upflow reactor. This method can significantly improve the yield of low-carbon olefins and light aromatics and the economic efficiency of the equipment.

Description

Method and device for producing low-carbon olefin and BTX by catalytic pyrolysis of hydrocarbon-containing raw oil

Technical Field

The application relates to petroleum refining and petrochemical processing processes, in particular to a method and a device for producing low-carbon olefin and BTX by catalytic cracking of full-fraction hydrocarbon-containing raw oil.

Background

With the continuous slow increase of the consumption of the finished oil, the demand of basic organic raw materials represented by low-carbon olefin, aromatic hydrocarbon and the like is increased at a high speed, and chemical industry refineries become the development trend in the future. The configuration of the chemical refinery at present mainly comprises the following three steps that firstly crude oil is subjected to pretreatment such as solvent deasphalting or hydrofining and then directly enters a steam cracking unit to produce chemical materials, but the mode is generally limited to light crude oil, secondly heavy naphtha is maximally generated after hydrocracking of all fractions of the crude oil, aromatic hydrocarbons are maximally produced through a reforming unit, thirdly, the light fraction of the crude oil enters the steam cracking unit, and the heavy fraction enters a catalytic cracking unit to maximally produce low-carbon olefins. 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. Among them, the catalytic cracking process has its unique advantages in terms of production of chemical materials and raw material adaptability, and can simultaneously produce propylene, ethylene and BTX.

Chinese patent CN1978411B discloses a combined process method for preparing micromolecular olefin, in which a catalytic cracking catalyst and a cracking raw material are mixed and contacted in a reactor, a spent catalyst and reaction oil gas are separated, wherein the spent catalyst is sent into a regenerator for burning regeneration, the regenerated thermal catalyst is divided into two parts, one part of regenerated thermal catalyst is returned to the reactor, the other part of regenerated thermal catalyst is firstly mixed and contacted with heavy petroleum hydrocarbon in another reactor, pre-coking is carried out, olefin raw material rich in C4-C8 is mixed and contacted with coked catalyst, catalytic cracking reaction is carried out, reaction oil gas of the spent catalyst is separated, the spent catalyst and the spent catalyst in the previous step are sent into the regenerator for burning regeneration, and the separated reaction oil gas is separated to obtain micromolecular olefin products such as propylene. The method can convert light raw materials rich in olefin into micromolecular olefin products such as propylene with high selectivity, and simultaneously maintain the heat balance of the device.

Chinese patent CN102899078a discloses a catalytic cracking process for producing propylene, which is based on a combined reactor composed of double riser and fluidized bed, wherein heavy raw oil and a first catalyst are introduced into the first riser reactor to react, and the oil is separated and then enters into a separation system. The cracked heavy oil is introduced into the second riser reactor to contact and react with the catalyst introduced into the second riser reactor, and the light hydrocarbon is introduced into the second riser reactor to contact and react with the mixture formed by the contact and reaction of the cracked heavy oil and the second 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 in the second riser reactor and the catalyst into the fluidized bed reactor for reaction. By optimizing the process scheme, a proper catalyst is provided, different feeds are selectively converted, and the yield of propylene and butene is high.

Chinese patent CN101045667B discloses a combined catalytic conversion method for producing more low-carbon olefins, which comprises contacting heavy oil raw material with regenerated catalyst and optional carbon deposition catalyst in a down-pipe reactor, introducing at least a part of the separated remaining products except low-carbon olefins into a riser reactor to react with the regenerated catalyst, introducing the catalyst into a catalyst pre-lifting section of the down-pipe reactor after the riser reaction, mixing with the regenerated catalyst entering the down-pipe reactor, and contacting with heavy oil raw material. The method adopts a combined reactor form that heavy oil raw materials react in a down reactor and intermediate product olefin reacts in a riser reactor, so that the yield of low-carbon olefin is improved.

Chinese patent CN109370644a discloses a method for preparing low-carbon olefine and aromatic hydrocarbon by catalytic cracking of crude oil, in which the crude oil is separated into light and heavy components, the cutting point is 150-300 deg.c, the light fraction and heavy fraction are reacted in different reaction zones of the same reactor, and the catalyst adopts aluminosilicate formed from silicon dioxide and aluminium oxide as main component, and includes alkali metal oxide, alkaline earth metal oxide, titanium, iron oxide, vanadium 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.

The method is researched from the aspects of novel reactor structure development, novel catalytic material development, control of reaction depth, improvement of propylene selectivity and the like, and a method for preparing low-carbon olefin and aromatic hydrocarbon by catalytic pyrolysis is provided, but a preparation method and a reactor structure for maximizing production of industrial materials aiming at crude oil are not provided at present.

Disclosure of Invention

The invention aims at providing a device and a method which are suitable for processing hydrocarbon-containing raw oil to perform catalytic cracking so as to furthest utilize the hydrocarbon-containing raw oil to produce low-carbon olefin and BTX, aiming at the characteristics of different hydrocarbon compositions and different cutting temperatures of various hydrocarbon-containing raw oil.

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

S1, cutting hydrocarbon-containing raw oil into light distillate and heavy distillate, wherein the weight ratio of the light distillate to the heavy distillate (light distillate/heavy distillate) is X;

S2, introducing the light distillate and a first stream of catalyst into a first downlink reactor for first catalytic pyrolysis to obtain a first catalytic pyrolysis material;

Optionally S2', introducing the material after the first catalytic cracking into a fluidized bed reactor for the second catalytic cracking to obtain a material after the second catalytic cracking;

S3, carrying out gas-solid separation on the material after the first catalytic cracking to obtain first reaction oil gas and a first spent catalyst, or carrying out gas-solid separation on the material after the second catalytic cracking to obtain second reaction oil gas and a second spent catalyst;

S4, introducing a continuous catalyst, the heavy distillate and a second catalyst into a second uplink reactor for third catalytic pyrolysis, and then performing gas-solid separation to obtain third reacted oil gas and a third spent catalyst, wherein the continuous catalyst is at least one part of the first spent catalyst or at least one part of the second spent catalyst, and the weight ratio of the second catalyst to the continuous catalyst (second catalyst/continuous catalyst) is R;

s5, separating low-carbon olefin and light aromatic hydrocarbon from any one of the first reaction oil gas, the second reaction oil gas and the third reaction oil gas or the mixture of the first reaction oil gas and the third reaction oil gas or the mixture of the second reaction oil gas and the third reaction oil gas, separating light olefin fraction, and returning the light olefin fraction to the second upflow reactor of the step S4 or the fluidized bed reactor of the step S2',

The R and X satisfy the following relation:

(4.84×T0-3340)/(780+5×T0-6×T3)<R/X<(0.968×T0-630)/(668+0.2×T0-1.2×T3)

T0 is the temperature (in degrees Celsius) at which the second stream of catalyst enters step S4, and T3 is the outlet temperature (in degrees Celsius) of the second upstream reactor.

Optionally, in the process of the present disclosure, the outlet temperature T3 of the second upgoing reactor is in the range of 530-650 ℃, preferably 560-640 ℃, more preferably 580-630 ℃, still more preferably 600-630 ℃, and/or the temperature T0 of the second stream of catalyst at the entry into step S4 is in the range of 690-750 ℃, preferably 700-740 ℃, still more preferably 705-730 ℃, still more preferably 710-725 ℃.

Alternatively, in the method of the present disclosure, in step S1, the hydrocarbon-containing raw oil is cut into light distillate and heavy distillate at an arbitrary temperature between 100 to 400 ℃ at the cutting point, so that the weight ratio of the light distillate to the heavy distillate (light distillate/heavy distillate) is X.

Optionally, in the method disclosed by the invention, the first catalytic cracking condition comprises that the outlet temperature of the first downward reactor is 610-720 ℃, the gas-solid residence time is 0.1-3.0 seconds, the catalyst-oil ratio is 15-80, and/or the second catalytic cracking condition comprises that the reaction temperature in the fluidized bed reactor is 600-690 ℃, the mass airspeed is 2-20h ^-1, and/or the third catalytic cracking condition comprises that the gas-solid residence time is 0.5-8 seconds and the catalyst-oil ratio is 8-40.

Optionally, in the method disclosed by the invention, the first catalytic cracking condition comprises that the outlet temperature of the first downward reactor is 650-690 ℃, the gas-solid residence time is 0.5-1.5 seconds, the catalyst-oil ratio is 25-65, and/or the second catalytic cracking condition comprises that the reaction temperature in the fluidized bed reactor is 640-670 ℃, the mass airspeed is 4-12h ^-1, and/or the third catalytic cracking condition comprises that the gas-solid residence time is 1.5-5 seconds and the catalyst-oil ratio is 10-30.

Optionally, in the process of the present disclosure, in step S4, the continuous catalyst is first mixed with the second catalyst and then subjected to a subsequent catalytic cracking reaction, and/or, in the presence of step S2', the separated catalyst is stripped in a gas-solid separation of step S3 to obtain a second spent catalyst, and/or, in step S4, the light olefin fraction from step S5 is subjected to catalytic cracking prior to contacting the heavy distillate with a mixture of the second catalyst and continuous catalyst, preferably the light olefin fraction is subjected to catalytic cracking prior to contacting the heavy distillate with a mixture of the second catalyst and continuous catalyst for 0.3-1.0 seconds, more preferably the light olefin fraction is subjected to catalytic cracking prior to contacting the heavy distillate with a mixture of the second catalyst and continuous catalyst for 0.4-0.8 seconds, and/or, in step S4, the process has a step S0 prior to step S1, wherein the dehydrated hydrocarbon-containing feedstock is subjected to desalting treatment to step S1 to obtain dehydrated feedstock.

Optionally, the method of the present disclosure further comprises stripping the separated catalyst in the gas-solid separation of step S4 to obtain a third to-be-produced catalyst, and/or separating the third to-be-produced catalyst and optionally the first to-be-produced catalyst or the second to-be-produced catalyst which does not enter the second ascending reactor at a temperature of 690-750 ℃, preferably 700-740 ℃, further preferably 705-730 ℃ and further preferably 710-725 ℃ to obtain a regenerated catalyst, and/or separating any one of the first, second and third reaction oil-gas or a mixture of the first and third reaction oil-gas to obtain a dry gas, a C3 fraction, a C4 fraction, light gasoline, heavy gasoline, diesel oil and slurry, separating light olefins from the third to obtain light olefins, and separating light olefins from the light olefins, and/or separating light olefins from the first, second and third reaction oil-gas in the absence of step S2', and returning the light olefins to the first, second and third reaction oil-gas to the third reaction oil-gas or a mixture of the second and third reaction oil-gas to the first and third reaction oil-gas in the first and third reaction oil-gas, or a mixture of the third reaction oil-gas in the first and third reaction oil-gas in the step S2, and the third reaction oil-gas is separated in the first and third reaction oil-gas, or the third reaction oil-gas in the step 2.

Optionally, in the method of the present disclosure, the hydrocarbon-containing raw oil is one or a mixture of two or more of crude oil, coal liquefied oil, synthetic oil, oil sand oil, shale oil, compact oil and animal and vegetable oil, or a hydro-modified oil of its respective partial fraction, its respective heavy fraction.

Alternatively, in the method of the present disclosure, the first and second catalysts each independently include an active component and a support, the active component is at least one selected from ultrastable Y-type zeolite, ZSM-5 series zeolite, high-silica zeolite having five-membered ring structure, and beta zeolite with or without rare earth, and the support is at least one selected from alumina, silica, amorphous silica alumina, zirconia, titania, boria, and alkaline earth metal oxide.

Optionally, in the method of the present disclosure, the first and second catalysts each independently comprise a regenerated catalyst, preferably the first and second catalysts are regenerated catalysts, and/or all of the first spent catalyst or all of the second spent catalyst are taken as continuous catalysts.

The present disclosure also provides a device for producing light olefins and light aromatics by catalytic cracking of a hydrocarbonaceous feedstock, the device comprising the following units:

a hydrocarbon-containing raw oil cutting unit in which a hydrocarbon-containing raw oil is cut into a light fraction oil and a heavy fraction oil such that a weight ratio of the light fraction oil to the heavy fraction oil (light fraction oil/heavy fraction oil) is X,

The first downward reaction unit is used for introducing the light distillate and the first strand of catalyst from the upper part of the reaction unit to perform first catalytic pyrolysis, and obtaining a material after the first catalytic pyrolysis below the reaction unit;

an optional fluidized bed reaction unit, wherein the material after the first catalytic cracking is introduced and subjected to the second catalytic cracking to obtain a material after the second catalytic cracking;

The first gas-solid separation unit is used for carrying out gas-solid separation on the material after the first catalytic pyrolysis is introduced to obtain first reaction oil gas and a first spent catalyst, or carrying out gas-solid separation on the material after the second catalytic pyrolysis is introduced to obtain second reaction oil gas and a second spent catalyst;

A second up-flow reaction unit, introducing a continuous catalyst, a second catalyst and the heavy distillate from the lower part of the reaction unit, performing a third catalytic cracking, obtaining a third catalytic cracked material above the reaction unit, wherein the continuous catalyst is at least one part of the first spent catalyst or at least one part of the second spent catalyst, the weight ratio of the second catalyst to the continuous catalyst (second catalyst/continuous catalyst) is R,

The second gas-solid separation unit is used for introducing the material subjected to the third catalytic pyrolysis to perform gas-solid separation to obtain third reaction oil gas and a third spent catalyst;

A separation unit in which any one of the first, second, and third reaction oil and gas or a mixture of the first and third reaction oil and gas or a mixture of the second and third reaction oil and gas is introduced, low-carbon olefins and light aromatics are separated, and a light olefin fraction is separated, and the light olefin fraction is returned to the second upflow reaction unit or the fluidized bed reaction unit;

Wherein, R and X satisfy the following relation:

(4.84×T0-3340)/(780+5×T0-6×T3)<R/X<(0.968×T0-630)/(668+0.2×T0-1.2×T3)

t0 is the temperature (in units of ℃) of the second stream of catalyst when entering the second upgoing reaction unit, and T3 is the outlet temperature (in units of ℃) of the second upgoing reaction unit.

Optionally, the apparatus of the present disclosure further comprises a regeneration unit, wherein the third spent catalyst and optionally the first spent catalyst or the second spent catalyst not entering the second up-reactor are introduced and subjected to a burn regeneration at a temperature of 690-750 ℃, preferably 700-740 ℃, further preferably 705-730 ℃, still further preferably 710-725 ℃ to obtain a regenerated catalyst.

Optionally, in the device disclosed by the disclosure, when the device comprises a fluidized bed reaction unit, the first gas-solid separation unit further comprises a stripping unit, wherein the catalyst obtained by gas-solid separation is stripped to obtain a second spent catalyst.

The second gas-solid separation unit also comprises a stripping unit, wherein the catalyst obtained by gas-solid separation is stripped to obtain a third spent catalyst.

Optionally, in the apparatus of the present disclosure, the apparatus further includes a dehydration and desalination unit, wherein the hydrocarbon-containing raw oil is subjected to a desalination and dehydration treatment, and the resulting dehydrated and desalinated hydrocarbon-containing raw oil is introduced into the hydrocarbon-containing raw oil cutting unit to be cut.

Optionally, in the apparatus of the present disclosure, the location of introducing the continuous catalyst and the second stream of catalyst in the second upgoing reaction unit is upstream of the feed inlet for the light olefin fraction.

Optionally, in the apparatus of the present disclosure, in the second upgoing reaction unit, the feed inlet for the light olefin fraction from the separation unit is upstream of the heavy fraction oil feed inlet.

Technical effects

According to the specific method, the hydrocarbon-containing raw oil is cut into two parts of light distillate and heavy distillate according to the hydrocarbon composition characteristics and cracking reaction characteristics of different fractions of the hydrocarbon-containing raw oil, and the light distillate is cracked at high temperature and short residence time in a downstream reactor, so that low-carbon olefin and BTX can be produced with high selectivity, and methane generation can be obviously reduced. Meanwhile, for heavy distillate oil, the production of light olefins and BTX can be maximized by adopting an upward reactor.

In addition, in the present disclosure, by providing a fluidized bed reactor at the lower portion of the first downflow reactor, light olefins in the catalytically cracked material can be further converted, and the production of light olefins can be maximized.

In the present disclosure, the light fraction oil residence time is short, the raw coke of the reaction is low, the yields of light olefins and BTX are high in the first downreactor, and in addition, the light olefin fraction is further converted in the fluidized bed reactor. Therefore, the first spent catalyst discharged from the first downlink reactor or the second spent catalyst discharged from the fluidized bed reactor still has higher activity, carbon deposit is loaded on the catalyst, and when the catalyst is used for the catalytic cracking of heavy distillate oil in the second uplink reactor, the yield of low-carbon olefin can be improved, and the generation of dry gas and coke can be inhibited.

More importantly, in the present disclosure, the weight ratio (X) of the light distillate and the heavy distillate obtained by cutting and the weight ratio (R) of the second catalyst and the continuous catalyst satisfy a specific relationship, so that the cutting ratio can be flexibly adjusted according to different hydrocarbon-containing raw oil types, and accordingly, the weight ratio of the second catalyst and the continuous catalyst is adjusted, so that the catalyst activity in the second upgoing reactor is more matched with the composition of the heavy distillate, and the yield of byproducts such as dry gas, coke and the like can be obviously reduced while the production of light olefins and BTX is maximized.

In addition, through the technical scheme, the method for producing the low-carbon olefin and the BTX by the catalytic pyrolysis of the hydrocarbon-containing raw oil can obviously improve the yield of the low-carbon olefin and the light aromatic hydrocarbon and the economical efficiency 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 one embodiment of an apparatus of the present disclosure.

Fig. 2 is a schematic diagram of another embodiment of the device of the present disclosure.

Description of the reference numerals

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.

Any particular value disclosed herein (including the endpoints of the numerical ranges) is not limited to the precise value of the value, and is to be understood to also encompass values near the precise value, such as all possible values within the range of + -5% of the precise value. Also, for a range of values disclosed, any combination of one or more new ranges of values between the endpoints of the range, between the endpoints and the specific points within the range, and between the specific points is contemplated as being specifically disclosed herein.

Unless otherwise indicated, terms used herein have the same meaning as commonly understood by one of ordinary skill in the art, and if a term is defined herein and its definition is different from the ordinary understanding in the art, then the definition herein controls.

In the present application, any matters or matters not mentioned are directly applicable to those known in the art without modification except for those explicitly stated. Moreover, any embodiment described herein can be freely combined with one or more other embodiments described herein, and the technical solutions or ideas thus formed are all deemed to be part of the original disclosure or original description of the present disclosure, and should not be deemed to be a new matter not disclosed or contemplated herein, unless such combination is clearly unreasonable by those skilled in the art.

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

The R and X satisfy the following relation:

(4.84×T0-3340)/(780+5×T0-6×T3)<R/X<(0.968×T0-630)/(668+0.2×T0-1.2×T3)

In the present disclosure, any one or a mixture of two or more of the first, second, and third reaction oil-gas is sometimes simply referred to as a reaction oil-gas.

In the present disclosure, low-carbon olefin refers to ethylene, propylene, butene, and isomers thereof. Light aromatics refer to BTX, i.e., benzene, toluene, and xylenes. In the present disclosure, light olefins may be separated from dry gas, C3 fraction and C4 fraction, and light aromatics may be separated from light gasoline and heavy gasoline.

In the present disclosure, the C3 fraction refers to hydrocarbons having 3 carbons including propane and propylene in the reaction oil gas, the C4 fraction refers to hydrocarbons having 4 carbons including butane, butene and isomers thereof in the reaction oil gas, the light gasoline refers to all or part of the distillation range of 30 to 90 ℃ in the reaction oil gas, wherein the "part fraction" refers to a fraction having a partial temperature range of 30 to 90 ℃ (for example, a fraction having a distillation range of 30 to 60 ℃ or 40 to 60 ℃ or 60 to 90 ℃ or the like), and the heavy gasoline refers to a fraction excluding the light gasoline in the distillation range of 30 to 200 ℃ in the reaction oil gas.

In the present disclosure, light distillate and heavy distillate refer to light distillate obtained by cutting hydrocarbon-containing raw oil at a certain cutting temperature, and the remainder is referred to as light distillate. The hydrocarbon-containing feedstock may be cut by those skilled in the art according to methods known in the art, including but not limited to fractional distillation, etc., as required, so long as the weight ratio of the light fraction oil to the heavy fraction oil (light fraction oil/heavy fraction oil) is X, and X satisfies the following relation of the present disclosure. In one embodiment of the present disclosure, X is between any two ranges of values selected from 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 2.0, 3.0, 4.0, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0. In one embodiment of the present disclosure, X is 0.1-2.0, preferably 0.12-1.0, further preferably 0.15-0.6.

In one embodiment of the present disclosure, in step S1, the hydrocarbonaceous feedstock is cut into light distillate and heavy distillate at any temperature between 100-400 ℃ at the cutting point such that the weight ratio of the light distillate to the heavy distillate (light distillate/heavy distillate) is X. In one embodiment of the present disclosure, the cutting point is, for example 150℃、160℃、170℃、180℃、190℃、200℃、210℃、220℃、230℃、240℃、250℃、260℃、270℃、280℃、290℃、300℃、310℃、320℃、330℃、340℃、350℃、360℃、370℃、380℃、390℃、400℃.

In the present disclosure, the hydrocarbon-containing feedstock may be any of various types of feedstock oils known in the art (in the present invention, hydrocarbon-containing feedstock oil may be simply referred to as feedstock oil), and may be, for example, one or a mixture of two or more of crude oil, coal liquefied oil, synthetic oil, oil sand oil, shale oil, compact oil, and animal and vegetable oils or a respective partial fraction thereof, or a respective heavy fraction thereof. In one embodiment of the present disclosure, the hydrocarbonaceous feedstock is preferably crude oil, a fraction of crude oil, or a hydro-upgraded oil of heavy oil from crude oil. It is known to those skilled in the art that "partial fractions" may be obtained by subjecting the feedstock oil to conventional treatments in the art, including, but not limited to, atmospheric distillation, vacuum distillation, and the like. The manner of this conventional process can be determined by one skilled in the art as desired. In one embodiment of the present disclosure, crude oil may be used as the hydrocarbonaceous feedstock of the present disclosure, crude oil may also be subjected to atmospheric distillation or vacuum distillation as needed, the remaining fraction after extraction of a part of the fraction (part of the crude oil) may be used as the hydrocarbonaceous feedstock of the present disclosure, or the product from the hydro-upgrading of heavy oil of crude oil (hydro-upgraded oil of heavy oil) may be used as the hydrocarbonaceous feedstock of the present disclosure as needed. It is known in the art that hydro-upgrading includes, but is not limited to, hydrodesulfurization, hydrodenitrogenation, hydrodemetallization, hydro-saturation, and the like.

In one embodiment of the present disclosure, the method has a step S0 before the step S1, wherein the hydrocarbon-containing raw oil is subjected to a desalting and dehydrating treatment, and the resulting dehydrated and desalted hydrocarbon-containing raw oil is introduced into the step S1 to be cut.

According to the present disclosure, in step S2, the conditions of the first catalytic cracking in the first downflow reactor include an outlet temperature of the first downflow reactor of 610-720 ℃, preferably 650-690 ℃. The conditions for the first catalytic cracking also include a gas-solid residence time of 0.1 to 3.0 seconds, preferably 0.5 to 1.5 seconds. In the first downflow reactor, the catalyst to light distillate ratio may be a catalyst to oil ratio (in terms of weight ratio of catalyst to light distillate) commonly used in catalytic cracking, and may be, for example, 15 to 80, preferably 25 to 65.

In the present disclosure, the mode of introducing the light distillate and the first catalyst into the first downflow reactor is not limited at all, as long as the light distillate and the first catalyst are introduced into the upper end of the first downflow reactor. Preferably, the light distillate and the first stream of catalyst are introduced separately from the different feed inlets of the first downgoing reactor.

In the present disclosure, the first-stage catalyst is not limited, and may be a catalyst known in the art to be useful for catalytic cracking of crude oil. For example, the first-strand catalyst may include an active component and a support, the active component being at least one selected from ultrastable Y-type zeolite, ZSM-5-series zeolite, high-silica zeolite having five-membered ring structure, and beta zeolite, with or without rare earth. The carrier is at least one selected from the group consisting of alumina, silica, amorphous silica-alumina, zirconia, titania, boria and alkaline earth oxides.

In one embodiment of the present disclosure, the structure of the first downflow reactor is not particularly limited as long as the feeding from the upper part and the discharging from the lower part can be achieved, and for example, it may be a downflow reactor of equal diameter or variable diameter.

In the present disclosure, since no additional heat source is used in the first downflow reactor, the outlet temperature of the first downflow reactor reflects the reaction temperature in the reactor. In the present disclosure, the catalytic cracking degree of light distillate in the first downflow reactor may be adjusted by adjusting the temperature of the first catalyst, the gas-solid residence time in the reactor, the outlet temperature of the first downflow reactor, and the like.

In one embodiment of the present disclosure, the first stream of catalyst is fresh catalyst. In one embodiment of the present disclosure, the first stream of catalyst comprises regenerated catalyst from a regenerator. Preferably, the first stream of catalyst is regenerated catalyst from a regenerator.

In the present disclosure, the temperature of the first catalyst entering the downgoing reactor is not particularly limited as long as it can be catalytically cracked when it contacts light distillate oil and satisfies the first catalytic cracking conditions described above in the present disclosure. When the regenerated catalyst is used as the first stream of catalyst, the first stream of catalyst is directly fed from the regenerator via a first stream of catalyst (regenerated catalyst) transfer pipe, and the temperature of the first stream of catalyst can be regarded as the temperature of the regenerator or the temperature at which the regenerated catalyst exits the regenerator (the temperature at the outlet of the regenerator) because the transfer pipe between the regenerator and the first downgoing reactor is short. In one embodiment of the present disclosure, the temperature of the first stream of catalyst entering the downgoing reactor is the temperature of the regenerator or the temperature at which the regenerated catalyst exits the regenerator (the temperature at the regenerator outlet) may generally be from 690 ℃ to 750 ℃, preferably from 700 ℃ to 740 ℃, more preferably from 705 ℃ to 730 ℃, still more preferably from 710 ℃ to 725 ℃. In this case, the catalyst from the regenerator may be further heated or cooled and then fed to the first downflow reactor, as needed. In the process of the present disclosure, fresh catalyst may be heated to a desired temperature at start-up and then introduced into the first downgoing reactor, after which regenerated catalyst from the regenerator may be employed directly. In one embodiment of the present disclosure, the first stream of catalyst is preferably fed directly from the regenerator without further heating or cooling thereof.

In the present disclosure, when introducing the light distillate into the first downgoing reactor, the light distillate may also be preheated first as needed. The temperature of the preheated light distillate is, for example, 30-100 ℃. Alternatively, the light distillate may be first subjected to steam atomization and then introduced into the first downflow reactor with steam as a carrier.

In the present disclosure, the first catalytically cracked material contains the first reaction oil gas obtained after catalytically cracking the light distillate and the first spent catalyst in which the first catalyst is coked (carbonized). The first spent catalyst still has higher activity, carbon deposit is loaded on the catalyst, and when the catalyst is used as a continuous catalyst to be introduced into a subsequent second uplink reactor, the catalyst is beneficial to the catalytic cracking of heavy distillate oil, the yield of low-carbon olefin is improved, and the generation of dry gas and coke is inhibited.

In the disclosure, in step S3, a gas-solid separation is performed on a material after the first catalytic cracking to obtain a first reaction oil gas and a first spent catalyst. The mode of gas-solid separation is not particularly limited, and the separation of the catalyst from the first reaction oil gas can be achieved by a method known in the art, for example, by using a settler or a cyclone.

In one embodiment of the present disclosure, the first reaction oil and gas is separated to obtain dry gas, C3 fraction, C4 fraction, light gasoline, heavy gasoline, diesel oil, and slurry oil, from which the light olefins and light aromatics are separated, and the light olefins fraction is separated. Wherein the C4 fraction and/or the light gasoline are/is the light olefin fraction. In one embodiment of the present disclosure, the first reaction oil gas is introduced into a fractionation device or a gas separation device for fractionation to achieve the above separation. In one embodiment of the present disclosure, the light olefin fraction is introduced into the second upgoing reactor in step S4 described below.

In one embodiment of the present disclosure, at least a portion of the first spent catalyst is introduced as a continuous catalyst into a second upgoing reactor described below. In one embodiment of the present disclosure, a first spent catalyst that does not enter a second upgoing reactor described below is introduced into a regeneration step, wherein regeneration of the catalyst is performed. Preferably, the entire first spent catalyst is introduced as a continuous catalyst into the second upflow reactor described below, in which case the amount of the first spent catalyst as a continuous catalyst corresponds substantially to the amount of the first stream of catalyst.

In one embodiment of the present disclosure, the material after the first catalytic cracking is subjected to gas-solid separation, and the separated catalyst is further subjected to steam stripping to remove hydrocarbon products adsorbed therein, so as to obtain a first spent catalyst.

In one embodiment of the present disclosure, step S2' may be further included after step S2 and before step S3, where the first catalytically cracked material is introduced into a fluidized bed reactor to perform the second catalytic cracking, so as to obtain a second catalytically cracked material, thereby further converting the light olefin fraction and maximizing the production of the light olefins.

In the present disclosure, a "fluidized bed reactor" is also referred to as a "fluidized reactor" having a catalyst density between 150 and 450kg/m ³.

In step S2', according to the present disclosure, the conditions of the second catalytic cracking in the fluidized bed reactor include a reaction temperature in the fluidized bed reactor of 600-690 ℃, preferably 640-670 ℃. The conditions for the second catalytic cracking also include a mass space velocity of 2 to 20h ^-1, preferably 4 to 12h ^-1.

According to one embodiment of the present disclosure, the catalytic cracking may be performed by directly introducing the first catalytically cracked material without introducing a new catalyst into the fluidized bed. According to one embodiment of the present disclosure, the heat of the first catalytically cracked material may be utilized directly without applying an additional heat source to the fluidized bed. The introduced first catalytically cracked material contains the first reacted oil gas obtained by catalytically cracking the light distillate and the first spent catalyst in which the first catalyst is coked (carbonized). The first spent catalyst still has higher activity, and can further convert light olefin fraction into low-carbon olefin by deepening the catalytic cracking degree in the fluidized bed reactor.

According to one embodiment of the present disclosure, a light olefin fraction is separated from the reaction oil and gas of the present disclosure and returned to the fluidized bed reactor for further conversion to light olefins. More specifically, the reaction oil and gas are separated to obtain dry gas, C3 fraction, C4 fraction, light gasoline, heavy gasoline, diesel oil and slurry oil, low-carbon olefin and light aromatic hydrocarbon are separated therefrom, and light olefin fraction is separated. Wherein the C4 fraction and/or the light gasoline are/is the light olefin fraction. In one embodiment of the present disclosure, the reaction oil gas is introduced into a fractionation device or a gas separation device to achieve the above separation.

In the present disclosure, the second catalytically cracked material comprises a second reaction oil gas and a second spent catalyst. The second spent catalyst still has higher activity, carbon deposit is loaded on the catalyst, and when the catalyst is used as a continuous catalyst to be introduced into a subsequent second uplink reactor, the catalyst is beneficial to the catalytic cracking of heavy distillate oil, the yield of low-carbon olefin is improved, and the generation of dry gas and coke is inhibited.

In the disclosure, in step S3, the material after the second catalytic cracking is subjected to gas-solid separation to obtain the second reaction oil gas and the second spent catalyst. The mode of gas-solid separation is not particularly limited, and the separation of the catalyst from the second reaction oil gas can be achieved by a method known in the art, for example, by using a settler or a cyclone.

In one embodiment of the present disclosure, the second reaction oil and gas is separated to obtain dry gas, C3 fraction, C4 fraction, light gasoline, heavy gasoline, diesel oil, and slurry oil, from which the light olefins and light aromatics are separated, and the light olefins fraction is separated. Wherein the C4 fraction and/or the light gasoline is light olefin fraction. In one embodiment of the present disclosure, the second reaction oil gas is introduced into a fractionation device or a gas separation device to achieve the above separation.

In one embodiment of the disclosure, the material after the second catalytic cracking is subjected to gas-solid separation, and the separated catalyst is further subjected to steam stripping to remove hydrocarbon products adsorbed in the separated catalyst, so as to obtain a second spent catalyst. In the present disclosure, at least a portion of the second spent catalyst is introduced as a continuous catalyst into a second upgoing reactor described below.

In one embodiment of the present disclosure, the second spent catalyst that does not enter the second upgoing reactor described below is introduced into a regeneration step, wherein regeneration of the catalyst is performed. Preferably, the entire second spent catalyst is introduced as a continuous catalyst into the second upflow reactor described below, in which case the amount of the second spent catalyst as a continuous catalyst corresponds substantially to the amount of the first stream of catalyst.

In the disclosure, in step S4, introducing a continuous catalyst, the heavy distillate and a second catalyst into a second uplink reactor, performing a third catalytic cracking, and then performing a gas-solid separation to obtain a third reaction oil gas and a third spent catalyst, where the continuous catalyst is at least a part of the first spent catalyst or at least a part of the second spent catalyst.

In one embodiment of the present disclosure, the conditions for the third catalytic cracking in the second upgoing reactor include an outlet temperature T3 of the second upgoing reactor of 530 to 650 ℃, preferably 560 to 640 ℃, more preferably 580 to 630 ℃, still more preferably 600 to 630 ℃. The conditions for the third catalytic cracking also include a gas-solid residence time of 0.5 to 8 seconds, preferably 1.5 to 5 seconds. In the second upflow reactor, the catalyst to heavy fraction oil ratio may be a catalyst to oil ratio (in terms of catalyst/heavy fraction oil weight ratio) commonly used in catalytic cracking, for example, may be 8 to 40, preferably 10 to 30.

In one embodiment of the present disclosure, in step S4, the continuous catalyst is first mixed with the second stream of catalyst, and then a subsequent catalytic cracking reaction is performed. More specifically, in one embodiment of the present disclosure, the continuous catalyst and the second stream of catalyst are each independently fed to the bottom of the second upflow reactor, mixed, and the mixed catalyst (hereinafter, sometimes referred to as a catalyst mixture or a mixed catalyst) is used for the catalytic cracking reaction in the second upflow reactor. In one embodiment of the present disclosure, after mixing the continuous catalyst with the second stream of catalyst in the bottom zone of the second upgoing reactor, the mixed catalyst is lifted in the second upgoing reactor using a pre-lift medium to perform a downstream catalytic cracking reaction. In one embodiment of the present disclosure, the pre-lifting medium may be dry gas, water vapor, or a mixture thereof.

In one embodiment of the present disclosure, in step S4, the second-stage catalyst is not limited, and may be a catalyst known in the art to be used for catalytic cracking of crude oil. For example, the second-strand catalyst includes an active component and a support, the active component being at least one selected from the group consisting of ultrastable Y-type zeolite with or without rare earth, ZSM-5 series zeolite, high-silica zeolite having five-membered ring structure, and beta zeolite. The carrier is at least one selected from the group consisting of alumina, silica, amorphous silica-alumina, zirconia, titania, boria and alkaline earth oxides.

In one embodiment of the present disclosure, the structure of the second upgoing reactor is not particularly limited as long as the feeding can be achieved from the bottom and the discharging can be achieved from the upper, for example, it may be a riser reactor with equal diameter or variable diameter, and a fluidized bed composite reactor.

In one embodiment of the present disclosure, the second stream of catalyst is fresh catalyst. In one embodiment of the present disclosure, the second stream of catalyst comprises regenerated catalyst from a regenerator. In one embodiment of the present disclosure, the second stream of catalyst is regenerated catalyst from a regenerator. When a fresh catalyst is used as the second-stage catalyst, it is necessary to preheat the catalyst so that the temperature at which the fresh catalyst enters step S4 satisfies the relational expression of the present disclosure. Preferably, the second stream of catalyst is regenerated catalyst from a regenerator.

In the present disclosure, the weight ratio of the second catalyst to the continuous catalyst (second catalyst/continuous catalyst) is R, and the R and X are such that the following relationship is satisfied:

(4.84×T0-3340)/(780+5×T0-6×T3)<R/X<(0.968×T0-630)/(668+0.2×T0-1.2×T3)

The inventors of the present disclosure have surprisingly found that by matching the cut ratio of light fraction oil and heavy fraction oil (weight ratio of light fraction oil/heavy fraction oil) of the hydrocarbonaceous feedstock oil in step S1 with the weight ratio of the second catalyst to the continuous catalyst (second catalyst/continuous catalyst) satisfying the above-mentioned relational expression, the hydrocarbonaceous feedstock oil component, the cut ratio, the catalyst activity (in particular, the catalyst activity in the second upflow reactor) can be better matched, and the yield of dry gas and coke can be significantly reduced while maximizing the production of light olefins and BTX. Without being bound by any theory, the inventors of the present disclosure speculate that the catalyst as a continuous catalyst comes from the first spent catalyst or the second spent catalyst, and because coking is low in the first downer reactor and in the fluidized bed reactor, the first spent catalyst and the second spent catalyst have higher catalytic activity while supporting a certain amount of carbon deposit, the catalyst is mixed with the second catalyst (fresh catalyst or regenerated catalyst from the regenerator) in a certain proportion, and the mixing proportion is matched with the cutting proportion of the hydrocarbon-containing raw oil, the above relation of the present disclosure is satisfied, and the obtained catalyst does not cause excessive coking of heavy distillate due to excessive high catalytic activity of the catalyst and insufficient catalytic cracking of heavy distillate due to excessive low catalytic activity of the catalyst. In the present disclosure, the ratio of cutting the hydrocarbon-containing raw oil into light distillate and heavy distillate and the mixing ratio of the continuous catalyst and the second catalyst satisfy a specific relationship, and the activity of the mixed catalyst in the second upflow reactor may be adjusted according to the composition, cutting ratio, etc. of the hydrocarbon-containing raw oil so that the yield of light olefins and BTX from the heavy distillate is maximized.

In one embodiment of the present disclosure, (4.84×t0-3340)/(780+5×t0-6×t3) is greater than 0. In the present disclosure, T0 is greater than T3.

In the present disclosure, T0 is the temperature at which the second catalyst strand enters step S4. Specifically, it refers to the temperature of the second stream of catalyst (fresh catalyst or regenerated catalyst) as it enters the second upgoing reactor, i.e., the temperature of it as it enters the bottom of the second upgoing reactor before mixing with the continuous catalyst. When the regenerated catalyst is used as the second-stage catalyst, since the transfer pipe between the regenerator and the second up-reactor is short, the temperature of the regenerator or the temperature of the catalyst when the regenerated catalyst exits the regenerator (the temperature of the outlet of the regenerator) can be regarded as the temperature at which the second-stage catalyst enters step S4.

In one embodiment of the present disclosure, the outlet temperature T3 of the second upgoing reactor is 530-650 ℃, preferably 560-640 ℃, more preferably 580-630 ℃, still more preferably 600-630 ℃, and/or the temperature T0 of the second stream of catalyst at step S4 is 690-750 ℃, preferably 700-740 ℃, still more preferably 705-730 ℃, still more preferably 710-725 ℃.

In one embodiment of the present disclosure, the third reaction oil and gas is separated to obtain dry gas, C3 fraction, C4 fraction, light gasoline, heavy gasoline, diesel oil, and slurry oil, from which the light olefins and light aromatics are separated, and the light olefin fraction is separated. Wherein the C4 fraction and/or the light gasoline is light olefin fraction. In one embodiment of the present disclosure, the third reaction oil gas is introduced into a fractionation device or a gas separation device to achieve the above separation.

In the present disclosure, when step S2' is not present, in step S5, light olefins and light aromatics are separated from either or both of the first reaction oil gas and the third reaction oil gas, and the separated light olefin fraction is returned to the second upgoing reactor.

In the present disclosure, when step S2' is present, in step S5, light olefins and light aromatics are separated from either or a mixture of the second reaction oil gas and the third reaction oil gas, and the separated light olefin fraction is returned to the fluidized bed reactor.

In one embodiment of the present disclosure, in step S4, the light olefin fraction from step S5 described below is contacted with the catalyst mixture prior to the heavy fraction oil, and a catalytic cracking reaction occurs, after which the heavy fraction oil is contacted with the catalyst mixture again, and a catalytic cracking reaction occurs. Preferably, the light olefin fraction is contacted with the catalyst mixture from 0.3 to 1.0 seconds prior to the heavy fraction oil. More preferably, the light olefin fraction is contacted with the catalyst mixture from 0.4 to 0.8 seconds prior to the heavy fraction oil.

In one embodiment of the disclosure, the product of the third catalytic cracking is subjected to gas-solid separation to obtain a third reaction oil gas and a third spent catalyst. The mode of gas-solid separation is not particularly limited, and the separation of the catalyst from the third reaction oil-gas can be achieved by a method known in the art, for example, by using a settler or a cyclone.

In one embodiment of the present disclosure, the material after the third catalytic cracking is subjected to gas-solid separation, and the separated catalyst is further subjected to steam stripping to remove the hydrocarbon products adsorbed therein, so as to obtain a third spent catalyst. In one embodiment of the present disclosure, the third spent catalyst is passed into a regenerator for regeneration of the catalyst.

In one embodiment of the present disclosure, the temperature of the regenerator is a temperature commonly used in the art, which may be 690-750 ℃, preferably 700-740 ℃, more preferably 705-730 ℃, still more preferably 710-725 ℃. In one embodiment of the present disclosure, the temperature of the regenerator or the temperature of the catalyst as the regenerated catalyst exits the regenerator (the temperature of the regenerator outlet) may be considered the temperature at which the second stream of catalyst enters step S4. Thus, in one embodiment of the present disclosure, the temperature T0 at which the second stream of catalyst enters step S4 may be 690-750 ℃, preferably 700-740 ℃, more preferably 705-730 ℃, still more preferably 710-725 ℃.

In one embodiment of the present disclosure, the regenerated catalyst is used as a first stream of catalyst and a second stream of catalyst.

In the present disclosure, in step S5, light olefins and light aromatics are separated from any one of the first, second, and third reaction oil and gas or a mixture of the second, and third reaction oil and gas, and a light olefin fraction is separated and returned to the second upflow reactor of step S4 or the fluidized bed reactor of step S2'. More specifically, the reaction oil and gas are separated to obtain dry gas, C3 fraction, C4 fraction, light gasoline, heavy gasoline, diesel oil and slurry oil, low-carbon olefin and light aromatic hydrocarbon are separated therefrom, and light olefin fraction is separated. Wherein the C4 fraction and/or the light gasoline are/is the light olefin fraction. Preferably, the reaction oil gas is introduced into a fractionation device or a gas separation device to achieve the above separation. In step S5, the first reaction oil gas and the third reaction oil gas may be separated separately, or may be combined and then uniformly separated, or the second reaction oil gas and the third reaction oil gas may be separated separately, or may be combined and then uniformly separated.

In one embodiment of the present disclosure, the method of separating the light olefin fraction from the reaction oil gas is not limited, and the separation may be performed in a manner known in the art, including but not limited to, a method of separating the liquefied gas and the stabilized gasoline after the reaction oil gas enters a fractionation and absorption stabilizing unit, a method of separating the liquefied gas into a C3 fraction and a C4 fraction in a subsequent gas separation device, and a method of separating the stabilized gasoline into a light and heavy gasoline separation tower. And C4 fraction and/or light gasoline are the light olefin fraction. From which low-carbon olefins and light aromatics can be separated.

In more detail, in one embodiment of the present disclosure, there is provided a method for producing light olefins and light aromatics by catalytic cracking of a hydrocarbon-containing feedstock oil, the method comprising the steps of:

s3, carrying out gas-solid separation on the material subjected to the first catalytic pyrolysis to obtain first reaction oil gas and a first spent catalyst;

S4, introducing a continuous catalyst, the heavy distillate and a second catalyst into a second uplink reactor for third catalytic pyrolysis, and then performing gas-solid separation to obtain third reaction oil gas and a third to-be-generated catalyst, wherein the continuous catalyst is at least one part of the first to-be-generated catalyst, and the weight ratio of the second catalyst to the continuous catalyst (second catalyst/continuous catalyst) is R;

S5, separating low-carbon olefin and light aromatic hydrocarbon from any one or a mixture of the first reaction oil gas and the third reaction oil gas, separating light olefin fraction, returning the light olefin fraction to the second upgoing reactor of the step S4,

The R and X satisfy the following relation:

(4.84×T0-3340)/(780+5×T0-6×T3)<R/X<(0.968×T0-630)/(668+0.2×T0-1.2×T3)

In more detail, in one embodiment of the present disclosure, there is provided a method for producing light olefins and light aromatics by catalytic cracking of a hydrocarbonaceous feedstock oil, the method comprising the steps of:

S2', introducing the material subjected to the first catalytic pyrolysis into a fluidized bed reactor for second catalytic pyrolysis to obtain a material subjected to the second catalytic pyrolysis;

S3, carrying out gas-solid separation on the material subjected to the second catalytic pyrolysis to obtain second reaction oil gas and a second spent catalyst;

s4, introducing a continuous catalyst, the heavy distillate and a second catalyst into a second uplink reactor for third catalytic pyrolysis, and then performing gas-solid separation to obtain third reaction oil gas and a third spent catalyst, wherein the continuous catalyst is at least one part of the second spent catalyst, and the weight ratio of the second catalyst to the continuous catalyst (second catalyst/continuous catalyst) is R;

S5, separating low-carbon olefin and light aromatic hydrocarbon from any one or a mixture of the second reaction oil gas and the third reaction oil gas, separating light olefin fraction, returning the light olefin fraction to the fluidized bed reactor in the step S2',

The R and X satisfy the following relation:

(4.84×T0-3340)/(780+5×T0-6×T3)<R/X<(0.968×T0-630)/(668+0.2×T0-1.2×T3)

In one embodiment of the present disclosure, the light olefin fraction is a C4 fraction in the reaction oil gas and/or the light gasoline.

The present disclosure also provides the following technical solutions:

A1, a method for producing light olefins and light aromatic hydrocarbons by catalytic cracking of hydrocarbon-containing raw oil, which comprises the following steps:

s1, cutting desalted and dehydrated hydrocarbon-containing raw oil into light distillate and heavy distillate, wherein the cutting point of the cutting is at any temperature of 100-400 ℃;

Optionally S2', feeding the material after the first catalytic cracking into a fluidized bed reactor for the second catalytic cracking to obtain a material after the second catalytic cracking;

S4, introducing a continuous catalyst, the heavy distillate and a second catalyst into a second uplink reactor for third catalytic pyrolysis, and then performing gas-solid separation to obtain third reaction oil gas and a third spent catalyst, wherein the continuous catalyst is the first spent catalyst or the second spent catalyst, and the weight ratio of the second catalyst to the continuous catalyst is 0.2-5:1;

s5, separating light olefin fraction from the first reaction oil gas and the second reaction oil gas, and returning the light olefin fraction to the fluidized bed reactor or the second upflow reactor.

A2, the method according to A1, wherein in the step S1, the cutting point of the cutting is any temperature between 200 ℃ and 380 ℃.

A3, the method according to A1, wherein in the step S4, the weight ratio of the second strand catalyst to the continuous catalyst is 0.5-3:1.

A4, the method according to claim A1, wherein,

In the first downlink reactor, the first catalytic cracking conditions comprise that the outlet temperature of the first downlink reactor is 610-720 ℃, and the gas-solid residence time is 0.1-3.0 seconds;

The second catalytic cracking conditions in the fluidized bed reactor comprise that the reaction temperature in the fluidized bed reactor is 600-670 ℃ and the mass airspeed is 2-20h ^-1;

In the second up-flow reactor, the third catalytic cracking condition comprises that the outlet temperature of the second up-flow reactor is 530-650 ℃, and the gas-solid residence time is 0.5-8 seconds.

A5, the method according to A4, wherein,

In the first downlink reactor, the first catalytic cracking conditions comprise that the outlet temperature of the first downlink reactor is 650-690 ℃, and the gas-solid residence time is 0.5-1.5 seconds;

the second catalytic cracking conditions in the fluidized bed reactor comprise that the reaction temperature in the fluidized bed reactor is 620-640 ℃ and the mass airspeed is 4-12h ^-1;

In the second up-flow reactor, the third catalytic cracking condition comprises that the outlet temperature of the second up-flow reactor is 560-640 ℃, and the gas-solid residence time is 1.5-5 seconds.

A6, the method according to A1, wherein,

The light olefin fraction is catalytically cracked with the second catalyst before the heavy fraction oil for 0.3-1.0 seconds, and preferably the light olefin fraction is catalytically cracked with the second catalyst before the heavy fraction oil for 0.4-0.8 seconds.

A7, the method according to A1, wherein the method further comprises:

Carrying out burning regeneration on the third spent catalyst to obtain a regenerated catalyst;

separating the first oil gas from the second oil gas to obtain dry gas, C3 fraction, C4 fraction, light gasoline, heavy gasoline, diesel oil and slurry oil;

The light olefin fraction is a C4 fraction in the first oil gas and the second oil gas and/or a fraction in the range of 30-90 ℃ in the first oil gas and the second oil gas.

A8, the method according to A1, wherein the hydrocarbon-containing raw 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.

A9, the method according to A1, wherein the first-strand catalyst and the second-strand catalyst each independently include an active component and a support, the active component being at least one selected from the group consisting of ultrastable Y-type zeolite with or without rare earth, ZSP-series zeolite, high-silica zeolite with five-membered ring structure, and beta zeolite.

A10, the method of A1, wherein the first and second catalysts each independently comprise the regenerated catalyst.

Wherein, R and X satisfy the following relation:

(4.84×T0-3340)/(780+5×T0-6×T3)<R/X<(0.968×T0-630)/(668+0.2×T0-1.2×T3)

In this disclosure, T0 is the temperature (in degrees celsius) at which the second stream of catalyst enters the second upgoing reaction unit. Specifically, it refers to the temperature of the second stream of catalyst as it enters the bottom of the second upgoing reaction unit before it is mixed with the continuous catalyst.

In one embodiment of the disclosure, the apparatus further comprises a regeneration unit, wherein the third spent catalyst and optionally the first spent catalyst or the second spent catalyst not entering the second up-reactor are introduced, and a burn-in regeneration is performed to obtain a regenerated catalyst. Preferably, only the third spent catalyst is introduced into the regeneration unit. In one embodiment of the present disclosure, the temperature of the regeneration unit is a temperature commonly used in the art, which may be 690-750 ℃, preferably 700-740 ℃, more preferably 705-730 ℃, still more preferably 710-725 ℃.

In one embodiment of the present disclosure, the outlet temperature T3 of the second upgoing reaction unit is 530-650 ℃, preferably 560-640 ℃, more preferably 580-630 ℃, even more preferably 600-630 ℃.

In one embodiment of the present disclosure, the temperature T0 of the second stream of catalyst as it enters the second upgoing reaction unit is 690-750 ℃, preferably 700-740 ℃, more preferably 705-730 ℃, still more preferably 710-725 ℃.

In one embodiment of the present disclosure, the apparatus further comprises a dehydration and desalination unit, wherein the hydrocarbon-containing raw oil is subjected to a desalination and dehydration treatment, and the resulting dehydrated and desalinated hydrocarbon-containing raw oil is introduced into the hydrocarbon-containing raw oil cutting unit to be cut.

In one embodiment of the present disclosure, the structure of the first downflow reaction unit is not particularly limited as long as the feeding from the upper portion and the discharging from the lower portion thereof can be achieved, and for example, it may be a downflow reactor of equal diameter or variable diameter.

In one embodiment of the present disclosure, in the absence of a fluidized bed reaction unit, light olefins and light aromatics are separated from either or a mixture of the first, third, or both reaction oils in a separation unit and the separated light olefin fraction is returned to the second upgoing reaction unit.

In the present disclosure, when a fluidized bed reaction unit is present, light olefins and light aromatics are separated from either or a mixture of the second reaction oil gas and the third reaction oil gas in a separation unit, and the separated light olefin fraction is returned to the fluidized bed reactor.

In one embodiment of the present disclosure, the first gas-solid separation unit and the second gas-solid separation unit comprise apparatuses known in the art that can perform gas-solid separation, and may include a settler or a cyclone, for example.

In one embodiment of the present disclosure, the apparatus further comprises at least one stripping unit, which may be disposed in the gas-solid separation unit, wherein the catalyst obtained by the gas-solid separation is stripped to remove hydrocarbon products adsorbed therein.

More specifically, in one embodiment of the present disclosure, when the apparatus includes a fluidized bed reaction unit, the first gas-solid separation unit further includes a stripping unit, where the catalyst obtained by gas-solid separation is stripped to remove hydrocarbon products adsorbed therein, to obtain a second spent catalyst. In one embodiment of the disclosure, the second gas-solid separation unit further includes a stripping unit, where the catalyst obtained by gas-solid separation is stripped to remove hydrocarbon products adsorbed therein, so as to obtain a third spent catalyst.

In one embodiment of the present disclosure, the continuous catalyst and the second stream of catalyst are introduced into the bottom of the second upgoing reaction unit, and after mixing, the mixed catalyst is used for subsequent catalytic cracking reactions.

In one embodiment of the present disclosure, the location of introduction of the continuous catalyst and the second stream of catalyst in the second upgoing reaction unit is upstream of the light olefin fraction feed.

In one embodiment of the present disclosure, in the second upgoing reaction unit, the light olefin fraction feed inlet is upstream of the heavy fraction oil feed inlet.

In more detail, the present disclosure provides an apparatus for producing light olefins and light aromatics by catalytic cracking of a hydrocarbonaceous feedstock, the apparatus comprising the following units:

The first gas-solid separation unit is used for carrying out gas-solid separation on the material after the first catalytic pyrolysis is introduced to obtain first reaction oil gas and a first spent catalyst;

A second up-going reaction unit, introducing a continuous catalyst, a second catalyst and the heavy distillate from the lower part of the reaction unit, performing third catalytic cracking, obtaining a material after third catalytic cracking above the reaction unit, wherein the continuous catalyst is at least one part of the first catalyst to be regenerated, the weight ratio of the second catalyst to the continuous catalyst (second catalyst/continuous catalyst) is R,

A separation unit in which a mixture of either or both of the first and third reaction oil gases is introduced, low-carbon olefins and light aromatics are separated, and a light olefin fraction is separated, and the light olefin fraction is returned to the second upgoing reaction unit;

Wherein, R and X satisfy the following relation:

(4.84×T0-3340)/(780+5×T0-6×T3)<R/X<(0.968×T0-630)/(668+0.2×T0-1.2×T3)

The fluidized bed reaction unit is used for introducing the material after the first catalytic pyrolysis and performing the second catalytic pyrolysis to obtain the material after the second catalytic pyrolysis;

The first gas-solid separation unit is used for carrying out gas-solid separation on the material after the second catalytic cracking is introduced to obtain second reaction oil gas and a second spent catalyst;

A second up-going reaction unit, introducing a continuous catalyst, a second catalyst and the heavy distillate from the lower part of the reaction unit, performing third catalytic cracking, obtaining a material after third catalytic cracking above the reaction unit, wherein the continuous catalyst is at least one part of the second spent catalyst, the weight ratio of the second catalyst to the continuous catalyst (second catalyst/continuous catalyst) is R,

A separation unit in which either one or both of the second reaction oil gas and the third reaction oil gas is introduced, light olefins and light aromatics are separated, and a light olefin fraction is separated, and the light olefin fraction is returned to the fluidized bed reaction unit;

Wherein, R and X satisfy the following relation:

(4.84×T0-3340)/(780+5×T0-6×T3)<R/X<(0.968×T0-630)/(668+0.2×T0-1.2×T3)

The device for producing low-carbon olefin and light aromatic hydrocarbon by catalytic pyrolysis of the hydrocarbon-containing raw oil is used for implementing the method for producing low-carbon olefin and light aromatic hydrocarbon by catalytic pyrolysis of the hydrocarbon-containing raw oil.

Hereinafter, two embodiments of the present disclosure will be described in detail with reference to fig. 1 and 2, respectively, but the present disclosure is not limited thereto.

One specific embodiment of the present disclosure is shown in fig. 1, where a hot first stream of catalyst (regenerated catalyst) is fed to a first downflow reactor 1 through a first stream of catalyst feed (regenerated catalyst feed) 12. Light distillate is sprayed into the first downward reactor 1 through the feeding nozzle 11, contacts with a first stream of catalyst and carries out catalytic cracking reaction, the reacted first catalytic cracked material is separated from oil and gas in the gas-solid separator 7, the obtained first reaction oil and gas is introduced into a separating device (not shown in the figure) through an oil and gas outlet of the downward reactor, a first spent catalyst is introduced into the bottom of the second upward reactor 3 as a continuous catalyst through the continuous catalyst conveying pipe 31, a second stream of catalyst (regenerated catalyst) is introduced into the bottom of the second upward reactor 3 through the second stream of catalyst conveying pipe (regenerated catalyst conveying pipe) 32, and the catalyst after the first spent catalyst (continuous catalyst) and the second stream of catalyst are mixed is lifted upwards through a pre-lifting medium. The light olefin fraction is injected into the second upflow reactor 3 through the light olefin fraction feed nozzle 21, contacts the catalyst and reacts. The heavy fraction oil is sprayed into the second ascending reactor 3 through the heavy fraction oil feeding nozzle 33 to contact and react with the oil mixture from the bottom, the reacted material is obtained after the reaction, the material enters the settler 4, the third catalyst to be regenerated is separated from the third reaction oil gas in the settler 4, the third reaction oil gas enters a separating device (not shown in the figure) through the third reactor oil gas outlet 41, the third catalyst to be regenerated enters the stripper 5 to strip out the adsorbed hydrocarbon product, the third catalyst to be regenerated is sent to the regenerator 6 through the conveying pipe 53 to be regenerated, and the regenerated catalyst is returned to the first descending reactor and the second ascending reactor for reuse. And (3) separating the reaction oil gas (the first reaction oil gas and the third reaction oil gas) through a separation device (preferably a fractionation device and a gas separation device) to obtain dry gas, C3 fraction, C4 fraction, light gasoline, heavy gasoline, diesel oil and slurry oil, and separating the dry gas, the C3 fraction, the C4 fraction, the light gasoline, the heavy gasoline, the diesel oil and the slurry oil from the separation device to obtain light olefins and light aromatic hydrocarbons. In addition, a light olefin fraction is separated from the reaction oil and gas and introduced into the second ascending reactor 3 through a light olefin fraction feed nozzle 21.

Another specific embodiment of the present disclosure is shown in fig. 2, where a hot first stream of catalyst (regenerated catalyst) is fed to the first downflow reactor 1 through a first stream of catalyst feed pipe (regenerated catalyst feed pipe) 12. Light distillate is sprayed into the first downlink reactor 1 through the feeding nozzle 11, contacts with a first stream of catalyst and carries out catalytic cracking reaction, the reacted first catalytic cracked material is introduced into the fluidized bed reactor 2 through the outlet mushroom head distributor 13 of the first downlink reactor, the cracking reaction is continuously carried out in the fluidized bed reactor, a second catalytic cracked material is obtained after the reaction, and the material is subjected to cyclone separation to obtain second reaction oil gas and a second spent catalyst. The second reaction oil gas is introduced into a separation device (not shown in the figure) from the second reaction oil gas outlet 22, the second spent catalyst enters the first stripper 51 to strip out adsorbed hydrocarbon products, then is introduced into the bottom of the second ascending reactor 3 as a continuous catalyst through a continuous catalyst conveying pipe 31, the second catalyst (regenerated catalyst) is introduced into the bottom of the second ascending reactor 3 through a second catalyst conveying pipe (regenerated catalyst conveying pipe) 32, and the catalyst after the second spent catalyst (continuous catalyst) and the second catalyst are mixed is lifted upwards through a pre-lifting medium. Heavy distillate oil is sprayed into the second ascending reactor 3 through the heavy distillate oil feeding nozzle 33 to be in contact with the catalyst for reaction, a material after third catalytic cracking is obtained after the reaction, the material enters the settler 4, the third spent catalyst and third reaction oil gas are separated in the settler 4, the third reaction oil gas is introduced into a separating device (not shown in the figure) through the third reactor oil gas outlet 41, the third spent catalyst enters the second stripper 52 to strip adsorbed hydrocarbon products, the third spent catalyst is sent to the regenerator 6 for regeneration through the third spent catalyst conveying pipe 53, and the regenerated catalyst is returned to the first descending reactor and the second ascending reactor for reuse. And (3) separating the reaction oil gas (the second reaction oil gas and the third reaction oil gas) by a separation device (preferably a fractionation device and a gas separation device) to obtain dry gas, C3 fraction, C4 fraction, light gasoline, heavy gasoline, diesel oil and slurry oil, and separating the dry gas, the C3 fraction, the C4 fraction, the light gasoline, the heavy gasoline, the diesel oil and the slurry oil from the separation device to obtain light olefins and light aromatic hydrocarbons. In addition, a light olefin fraction is separated from the reaction oil gas and returned to the fluidized-bed reactor 2 from the light olefin fraction feed nozzle 21.

Examples

The present disclosure is further illustrated in detail by the following examples. The starting materials used in the examples are all available commercially. The catalytic cracking catalysts used in the examples and comparative examples of the present disclosure were industrially produced by the catalyst ziluta corporation, a chinese petrochemical company, with the trade designation DMMC-2. The catalyst contains ZSM-5 zeolite with average pore diameter less than 0.7 nm and ultrastable Y-type zeolite, and is subjected to saturated steam thermal aging for 17 hours at 800 ℃ before being used, and the main physicochemical properties of the catalyst are shown in table 1. The hydrocarbon-containing raw oil used in examples and comparative examples was crude oil from Jiangsu oilfield, and its properties are shown in Table 2.

TABLE 1

Catalyst	Catalyst
		Physical Properties
Specific surface/m ²·g^-1	125
		Pore volume/cm ^-3·g^-1	0.197
Apparent density g cm ^-3	0.86
		Chemical composition
Al₂O₃/%	56.8
		SiO₂/%	42.9
Microreaction/%	68

TABLE 2

Project	Crude oil A
		Density (20 ℃ C.)/(g cm ^-3)	0.849
Freezing point/°c	35
		Kinematic viscosity (80 ℃ C.)/(mm ²/s)	6.8
Residual carbon/%	3.5
		Gum content/%	8.4
Asphaltene content/%	0.2
		Fraction mass fraction/%less than 250 °c	16.3
Fraction mass fraction/%less than 320 °c	28.6
		Fraction mass fraction/%less than 350 °c	34.6

Example 1

The crude oil a light and heavy fraction oil processed in this example had a cut point of 320 ℃ and a cut ratio (weight ratio of light fraction oil/heavy fraction oil) of 0.4.

Experiments were performed using a medium-sized unit modified for continuous reaction-regeneration operations, the flow scheme of which is shown in FIG. 1. The 720 ℃ high-temperature regenerated catalyst is introduced into the top of the first downlink reactor 1 through a regeneration inclined tube by a regenerator, light distillate oil preheated to 45 ℃ is atomized by steam, enters the first downlink reactor 1 through a feed nozzle to contact with a first stream of catalyst for catalytic cracking reaction, the catalyst-to-oil ratio is 40, the outlet temperature of the reactor is 665 ℃, the gas-solid residence time is 0.8s, the first catalytic cracking material is subjected to cyclone separation to obtain first reaction oil gas and a first spent catalyst, the first reaction oil gas enters a separation system, and all the first spent catalyst is introduced into the bottom of the second uplink reactor 3. While regenerated catalyst (second stream of catalyst) having a temperature of 720C is introduced from the regenerator via regenerated catalyst transfer line 32 to the bottom of the second upgoing reactor 3. The weight ratio of the second catalyst to the first catalyst to be regenerated (the second catalyst/the first catalyst to be regenerated) is 0.25, after the first catalyst to be regenerated and the second catalyst are mixed at the bottom of the second up-flow reactor 3, the mixed catalyst flows upwards under the action of pre-lifting steam, meanwhile, light olefin fraction enters the lower part of the second up-flow reactor 3 through a light olefin fraction feeding nozzle under an atomized water vapor medium to react in contact with the mixed catalyst, a heavy fraction oil nozzle is arranged at the position 800 mm above the light olefin fraction feeding nozzle, heavy fraction oil is atomized by water vapor and then is sprayed into a riser tube through the heavy fraction oil feeding nozzle to react for catalytic cracking reaction, the catalyst-oil ratio is 20, the outlet temperature T3 of the reactor is 610 ℃, the gas-solid residence time in the reactor is 1.5s, the materials after catalytic cracking are introduced into a settler for oil-gas separation, and are separated into a third reaction catalyst and a third oil-gas separation system, and the third reaction oil-gas is introduced into a separation system. The first reaction oil gas and the third reaction oil gas are separated into cracked gas, light gasoline, heavy gasoline, diesel oil and slurry oil in a separation system. A light gasoline fraction (distillation range 30-60 ℃) is returned as a light olefin fraction to the second upflow reactor 3 through a light olefin fraction feed nozzle. The third spent catalyst enters a stripper, hydrocarbon products adsorbed on the third spent catalyst are stripped, and then enter a regenerator through a spent agent inclined tube, and the regenerator is burnt and regenerated at 720 ℃ in contact with air. The regenerated catalyst returns to the reactor for recycling through a regeneration inclined tube. The medium-sized device maintains the temperature of the reaction-regeneration system by using electric heating. After the device runs stably (the composition of the product is basically unchanged), the composition of the cracked gas and the gasoline obtained from the reaction oil gas is analyzed to obtain the yields of low-carbon olefin (referred to as triene hereinafter) and light aromatic hydrocarbon (referred to as BTX hereinafter) in the product.

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

Example 2

The same apparatus and reaction procedure as in example 1 were employed, except that the light and heavy fraction cut point of the crude oil a processed was 250 ℃, the cut ratio (weight ratio of light fraction oil/heavy fraction oil) was 0.195, the weight ratio of the second catalyst to the first spent catalyst (second catalyst/first spent catalyst) was 0.03, the temperature of the regenerator was 700 ℃ (i.e., the temperature T0 at which the second catalyst entered step S4 was 700 ℃) and the outlet temperature T3 of the second upflow reactor was 570 ℃.

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

Example 3

The same apparatus and reaction procedure as in example 1 were employed, except that the light and heavy fraction cut point of the crude oil a processed was 350 ℃, the cut ratio (weight ratio of light fraction oil/heavy fraction oil) was 0.529, the weight ratio of the second catalyst to the first catalyst to be regenerated (second catalyst/first catalyst to be regenerated) was 0.6, the temperature of the regenerator was 740 ℃ (i.e., the temperature T0 at which the second catalyst entered step S4 was 740 ℃) and the outlet temperature T3 of the second upflow reactor was 630 ℃.

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

Example 4

The same apparatus and reaction procedure as in example 1 were used.

The crude oil a light and heavy fraction oil processed in this example had a cut point of 250 ℃ and a cut ratio (weight ratio of light fraction oil/heavy fraction oil) of 0.195.

The same conditions as in example 1 were employed except for the conditions listed in table 3.

The results are shown in Table 3.

Example 5

The same apparatus and reaction procedure as in example 1 were used.

The crude oil a light and heavy distillate cut point processed in this example was 350C, the cut ratio was (light distillate/heavy distillate weight ratio) 0.529,

The results are shown in Table 3.

Example 6

The cut point of the light and heavy fraction oil of the crude oil A processed was 320℃and the cutting ratio (weight ratio of light fraction oil to heavy fraction oil) was 0.4.

Experiments were performed using a medium-sized unit modified for continuous reaction-regeneration operations, the flow scheme of which is shown in FIG. 2. The 720 ℃ high-temperature regenerated catalyst is introduced into the top of a first downlink reactor 1 through a regeneration inclined tube by a regenerator, light distillate oil preheated to 45 ℃ is atomized by steam and enters the first downlink reactor 1 through a feeding nozzle to contact with a first strand of catalyst for catalytic cracking reaction, the catalyst-to-oil ratio is 40, the outlet temperature of the reactor is 670 ℃, the gas-solid residence time is 0.6s, the material after the first catalytic cracking enters a fluidized bed reactor 2 through an outlet distributor to further perform catalytic cracking reaction, the reaction temperature is 655 ℃, the mass airspeed is 4h ^-1, in addition, the light olefin fraction enters the bottom of the fluidized bed reactor 2 through a feeding nozzle 21 to react with the hot catalyst after the steam atomization, the material after the second catalytic cracking is cyclone separated to obtain second reaction oil gas and a second spent catalyst, the second reaction oil gas is introduced into a subsequent separation system, and the separated second spent catalyst is completely introduced into the bottom of a second uplink reactor 3 after the steam stripping. While regenerated catalyst (second stream of catalyst) having a temperature of 720C is introduced from the regenerator via regenerated catalyst transfer line 32 to the bottom of the second upgoing reactor 3. The weight ratio of the second catalyst to the second spent catalyst (the second catalyst/the second spent catalyst) is 0.25, the second spent catalyst and the second catalyst are mixed at the bottom of the second up-flow reactor 3, the mixed catalyst flows upwards under the action of pre-lifting steam, heavy distillate oil is sprayed into the second up-flow reactor 3 through a heavy distillate oil nozzle after being atomized by water vapor, the catalyst is contacted with the catalyst to generate catalytic cracking reaction, the catalyst-oil ratio is 20, the outlet temperature T3 of the reactor is 610 ℃, the gas-solid residence time in the reactor is 1.5s, the materials after catalytic cracking are introduced into a settler to be separated into third reaction oil gas and third spent catalyst, and the reaction oil gas is introduced into a separation system. The second reaction oil gas and the third reaction oil gas are separated into cracked gas, light gasoline, heavy gasoline, diesel oil and slurry oil in a separation system. The light gasoline fraction (distillation range 30-60 ℃) is returned as light olefin fraction to the fluidized-bed reactor 2. And the third spent catalyst enters a stripper, hydrocarbon products adsorbed by the third spent catalyst are stripped, and then enter a regenerator through a spent agent inclined tube, and the regenerator is burnt and regenerated at 720 ℃ in contact with air. The regenerated catalyst 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. After the device is operated stably (the composition of the product is basically kept unchanged), the composition of the cracked gas and the gasoline obtained from the reaction oil gas is analyzed to obtain the yield of triene and BTX in the product.

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

Example 7

The same apparatus and reaction procedure as in example 6 were employed, except that the light and heavy fraction cut point of the crude oil a processed was 250 ℃, the cut ratio (weight ratio of light fraction oil/heavy fraction oil) was 0.195, the weight ratio of the second catalyst to the second spent catalyst (second catalyst/second spent catalyst) was 0.03, the temperature of the regenerator was 700 ℃ (i.e., the temperature T0 at which the second catalyst entered step S4 was 700 ℃) and the outlet temperature T3 of the second upflow reactor was 570 ℃.

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

Example 8

The same apparatus and reaction procedure as in example 6 were employed, except that the light and heavy fraction cut point of the crude oil a processed was 350 ℃, the cut ratio (weight ratio of light fraction oil/heavy fraction oil) was 0.529, the weight ratio of the second catalyst to the second spent catalyst (second catalyst/second spent catalyst) was 0.6, the temperature of the regenerator was 740 ℃ (i.e., the temperature T0 at which the second catalyst entered step S4 was 740 ℃) and the outlet temperature T3 of the second upflow reactor was 630 ℃.

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

Comparative example 1

The same apparatus and reaction steps and reaction conditions as in example 1 were employed, except that the light olefin fraction separated from the reaction oil and gas was not refluxed to the second upflow reactor 3.

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

Comparative example 2

The same apparatus and reaction procedure as in example 1 was employed, except that the weight ratio of the second catalyst to the first catalyst to be regenerated (second catalyst/first catalyst to be regenerated) was 0.1, the temperature of the regenerator was 740 ℃ (i.e., the temperature T0 at which the second catalyst entered step S4 was 740 ℃), and the outlet temperature T3 of the second upflow reactor was 610 ℃.

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

Comparative example 3

The same apparatus and reaction procedure as in example 1 was employed, except that the weight ratio of the second catalyst to the first catalyst to be regenerated (second catalyst/first catalyst to be regenerated) was 0.5, the temperature of the regenerator was 700 ℃ (i.e., the temperature T0 at which the second catalyst entered step S4 was 700 ℃), and the outlet temperature T3 of the second upflow reactor was 610 ℃.

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

Comparative example 4

The same apparatus and reaction steps and reaction conditions as in example 1 were employed, except that the second catalyst was not introduced at the lower part of the second up-reactor 3, but only the first spent catalyst was used.

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

Comparative example 5

The same apparatus and reaction steps and reaction conditions as in example 1 were employed, except that the first spent catalyst was not introduced at the lower part of the second upgoing reactor 3, and only the second catalyst was used.

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

Comparative example 6

The same apparatus and reaction steps and reaction conditions as in example 1 were employed, except that the light distillate was fed into the second up-reactor, i.e., the first down-reactor 1 was changed to the second up-reactor (each parameter of the first down-reactor in Table 3 represents each parameter of the up-tube reactor in this comparative example 6).

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

As can be seen from the data in table 3, the method for producing light olefins and BTX by catalytic cracking of the hydrocarbon-containing feedstock oil provided by the present disclosure can significantly improve the yields of light olefins and light aromatics, and simultaneously, the yields of byproducts such as dry gas and coke are suppressed.

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 low-carbon olefins and light aromatics by catalytic cracking of hydrocarbon feedstock oil, the method comprising the following steps:

S1. The hydrocarbon-containing feedstock oil is cut into light distillate oil and heavy distillate oil, wherein the weight ratio of the light distillate oil to the heavy distillate oil is X;

S2. The light distillate oil and the first catalyst are introduced into the first downward reactor to carry out the first catalytic cracking to obtain the material after the first catalytic cracking.

S3. Perform gas-solid separation on the material after the first catalytic cracking to obtain the first reaction oil and gas and the first catalyst to be generated;

S4. The continuous catalyst, the heavy distillate oil, and the second catalyst are introduced into the second upward reactor for third catalytic cracking, followed by gas-solid separation to obtain third reaction oil and gas and third catalyst to be generated; the continuous catalyst is at least a portion of the first catalyst to be generated; the weight ratio of the second catalyst to the continuous catalyst is R.

S5. Separate low-carbon olefins and light aromatics from either the first reactant gas and the third reactant gas, or a mixture of the first reactant gas and the third reactant gas, and separate the light olefin fraction, returning the light olefin fraction to the second upward reactor in step S4.

R and X satisfy the following relationship:

(4.84×T0-3340)/(780+5×T0-6×T3)<R/X<(0.968×T0-630)/(668+0.2×T0-1.2×T3)

T0 is the temperature at which the second catalyst enters step S4, in °C, and T3 is the outlet temperature of the second upward reactor, in °C.

2. The method according to claim 1, wherein the outlet temperature T3 of the second upward reactor is 530-650°C; and/or

The temperature T0 when the second catalyst enters step S4 is 690-750℃.

3. The method according to claim 1 or 2, wherein, in step S1, the hydrocarbon-containing feedstock oil is cut into light distillate oil and heavy distillate oil at any temperature between 100-400°C, such that the weight ratio of the light distillate oil to the heavy distillate oil is X.

4. The method according to claim 1 or 2, wherein,

In the first downward-flowing reactor, the conditions for the first catalytic cracking include: an outlet temperature of 610-720°C, a gas-solid residence time of 0.1-3.0 seconds, and a catalyst-to-oil ratio of 15-80; and/or

In the second upward reactor, the conditions for the third catalytic cracking include: a gas-solid residence time of 0.5-8 seconds and a catalyst-to-oil ratio of 8-40.

5. The method according to claim 1 or 2, wherein,

In the first downward-flowing reactor, the conditions for the first catalytic cracking include: an outlet temperature of 650-690°C, a gas-solid residence time of 0.5-1.5 seconds, and a catalyst-to-oil ratio of 25-65; and/or

In the second upward reactor, the conditions for the third catalytic cracking include: a gas-solid residence time of 1.5-5 seconds and an agent-to-oil ratio of 10-30.

6. The method according to claim 1 or 2, wherein,

In step S4, the continuous catalyst is first mixed with the second catalyst stream, and then the subsequent catalytic cracking reaction is carried out; and/or

In step S4, the light olefin fraction from step S5 is contacted before the heavy distillate oil with the mixture of the second catalyst and the continuous catalyst; and/or

The method has a step S0 before step S1, wherein the hydrocarbon-containing feedstock oil is desalted and dehydrated, and the resulting dehydrated and desalted hydrocarbon-containing feedstock oil is introduced into step S1 for cutting.

7. The method according to claim 1 or 2, wherein the method further comprises:

In the gas-solid separation of step S4, the separated catalyst is stripped to obtain a third catalyst to be produced; and/or

The third spent catalyst and the first spent catalyst that did not enter the second upward reactor are subjected to coke regeneration at a temperature of 690-750°C to obtain a regenerated catalyst; and/or

Separating either the first reacted oil and gas or the third reacted oil and gas, or a mixture thereof, yields dry gas, C3 fraction, C4 fraction, light gasoline, heavy gasoline, diesel, and slurry oil. Low-carbon olefins and light aromatics are separated from these components, and a light olefin fraction is also separated.

In step S5, a light olefin fraction is separated from either the first reaction oil and gas, the third reaction oil and gas, or a mixture of both, and the light olefin fraction is returned to the second upward reactor in step S4.

8. The method according to claim 1 or 2, wherein the hydrocarbon-containing feedstock is one or a mixture of two or more of crude oil, coal liquefaction oil, synthetic oil, oil sands oil, shale oil, tight oil and animal and vegetable oils, or hydrotreated oils of a portion thereof or of a heavy fraction thereof.

9. The method according to claim 1 or 2, wherein the first catalyst and the second catalyst each independently comprise an active component and a support, the active component being at least one selected from ultrastable Y-type zeolite with or without rare earth elements, ZSM-5 series zeolite, high-silica zeolite with a five-membered ring structure, and β-zeolite, and the support being at least one selected from alumina, silicon oxide, amorphous aluminum silicate, zirconium oxide, titanium oxide, boron oxide, and alkaline earth metal oxides.

10. The method according to claim 1 or 2, wherein the first catalyst and the second catalyst each independently comprise a regenerated catalyst, and/or

The entirety of the first catalyst to be produced is used as a continuous catalyst.

11. The method according to claim 1, wherein, after step S2, step S2' is performed, wherein the material after the first catalytic cracking is introduced into a fluidized bed reactor for second catalytic cracking to obtain the material after the second catalytic cracking;

In step S3, the material after the second catalytic cracking is subjected to gas-solid separation to obtain the second reaction oil and gas and the second catalyst to be generated;

In step S4, the continuous catalyst, the heavy distillate oil, and the second catalyst are introduced into the second upward reactor for third catalytic cracking, followed by gas-solid separation to obtain the third reaction oil and gas and the third catalyst to be generated; the continuous catalyst is at least a part of the second catalyst to be generated.

In step S5, low-carbon olefins and light aromatics are separated from either the second reaction oil and gas or the third reaction oil and gas or a mixture thereof, and a light olefin fraction is separated and returned to the second upward reactor in step S4 or to the fluidized bed reactor in step S2'.

12. The method according to claim 11, wherein,

In the fluidized bed reactor, the conditions for the second catalytic cracking include: a reaction temperature of 600-690℃ and a mass hourly space velocity of 2-20 ^h⁻¹ ; and/or

In step S2', during the gas-solid separation in step S3, the separated catalyst is stripped to obtain a second catalyst to be produced; and/or

The entirety of the second catalyst to be generated is used as a continuous catalyst; and/or

Separating either the second or third reacted oil and gas, or a mixture thereof, yields dry gas, C3 fraction, C4 fraction, light gasoline, heavy gasoline, diesel, and slurry oil. Low-carbon olefins and light aromatics are separated from these fractions, along with a light olefin fraction; and/or

In step S5, a light olefin fraction is separated from either the second or third reaction oil/gas, or a mixture of both, and the light olefin fraction is returned to the fluidized bed reactor of step S2'; and/or

The third spent catalyst and the second spent catalyst that did not enter the second upward reactor were coked and regenerated at a temperature of 690-750°C to obtain a regenerated catalyst.

13. The method according to claim 11 or 12, wherein,

In the fluidized bed reactor, the conditions for the second catalytic cracking include: a reaction temperature of 640-670℃ and a mass hourly space velocity of 4-12 ^h⁻¹ .

14. The method according to claim 1 or 2, wherein at least one of the following conditions is satisfied:

The outlet temperature T3 of the second upward reactor is 600-630℃; and/or

The temperature T0 when the second catalyst enters step S4 is 710-725℃; and/or

In step S4, the light olefin fraction is contacted with the mixture of the second catalyst and the continuous catalyst 0.4-0.8 seconds before the heavy distillate oil; and/or

The third unregenerated catalyst is regenerated by coking at a temperature of 710-725°C to obtain a regenerated catalyst; and/or

The first and second catalyst streams are regenerated catalysts.

15. The method according to claim 1 or 2, wherein the third spent catalyst and the first spent catalyst that did not enter the second upward reactor are subjected to coke regeneration at a temperature of 710-725°C to obtain a regenerated catalyst.

16. The method according to claim 11 or 12, wherein the third spent catalyst and the second spent catalyst that did not enter the second upward reactor are subjected to coke regeneration at a temperature of 710-725°C to obtain a regenerated catalyst.