TWI899361B - Method and device for producing light olefins and BTX by catalytic cracking of hydrocarbon-containing raw oil - Google Patents

Abstract

The present invention relates to a method for producing light olefins and light aromatics by catalytic cracking of hydrocarbon-containing raw oil. The method comprises: cutting the hydrocarbon-containing raw oil into light distillate oil and heavy distillate oil; introducing the light distillate oil and a first stream of catalyst into a down-type reactor for catalytic cracking to obtain a first catalytic cracked material; performing gas-solid separation on the first catalytic cracked material to obtain a first reaction oil gas and a first spent catalyst; or, feeding the first catalytic cracked material into a After catalytic cracking in a fluidized bed reactor, gas-solid separation is performed to produce a second reaction gas and a second spent catalyst. The continuous catalyst, heavy distillate oil, and the second catalyst stream are introduced into an ascending reactor for catalytic cracking followed by gas-solid separation to produce a third gas and a third spent catalyst. Light olefins and light aromatics are separated from the reaction gas and a light olefin distillate fraction is then separated and returned to the fluidized bed reactor or the ascending reactor. This method significantly improves the yield of light olefins and light aromatics and the economics of the plant.

Description

Method and device for producing light olefins and BTX by catalytic cracking of hydrocarbon-containing raw oil

This application relates to petroleum refining and petrochemical processing, and specifically, to a method and apparatus for producing light olefins and BTX by catalytic cracking of fully distilled hydrocarbon-containing feedstock oil.

With the continued slowdown in the growth rate of refined oil consumption and the rapid growth in demand for basic organic raw materials, such as light olefins and aromatics, chemical refineries are becoming a future development trend. Currently, chemical refinery configurations primarily include the following: First, crude oil undergoes pre-treatment such as solvent deasphalting or hydrorefining before being directly fed into a steam cracking unit to produce chemical feedstocks. However, this approach is generally limited to light crude oil. Second, crude oil fractions are hydrocrackered to maximize heavy naphtha production, which is then fed into a reforming unit to maximize aromatics production. Third, the light fraction of crude oil is fed into a steam cracking unit, while the heavy fraction is fed into a catalytic cracking unit to maximize light olefin production. All three of the above methods have been industrialized, with chemical yields ranging from 35% to 55%. As can be seen, the configuration of existing chemical refineries primarily relies on a combination of core equipment, including steam cracking, reforming, hydrorefining, hydrocracking, and catalytic cracking. Among them, the catalytic cracking process has unique advantages in terms of chemical production and feedstock adaptability, and can simultaneously produce propylene, ethylene, and BTX.

Chinese Patent CN1978411B discloses a combined process for producing small molecule alkenes. In this process, a catalytic cracking catalyst and cracking feedstock are mixed and contacted in a reactor, and the spent catalyst and reaction oil gas are separated. The spent catalyst is fed into a regenerator for coking and regeneration. The regenerated hot catalyst is then divided into two parts. One part of the regenerated hot catalyst is returned to the reactor; the other part is returned to the reactor. The partially regenerated hot catalyst is first mixed with heavy petroleum hydrocarbons in a separate reactor for pre-coking. A C4-C8 olefin-rich feedstock is then mixed with the coked catalyst for a catalytic cracking reaction. The spent catalyst and reaction oil/gas are separated and then fed into a regenerator along with the spent catalyst from the previous step for coking and regeneration. The reaction oil/gas is then separated to produce propylene and other small olefin products. This method can highly selectively convert olefin-rich light feedstock into propylene and other small olefin products while maintaining the thermal balance of the unit.

Chinese Patent CN102899078A discloses a catalytic cracking method for producing propylene. This method is based on a dual-riser and fluidized bed reactor combination. First, heavy crude oil and a first stream of catalyst are introduced into the first riser reactor for reaction. After the oil and catalyst are separated, they enter a separation system. The cracked heavy oil is then introduced into a second riser reactor for a contact reaction with the catalyst introduced into the second riser reactor. Light hydrocarbons, including C4 hydrocarbons or gasoline distillates obtained in the product separation system, are then introduced into the second riser reactor for a contact reaction with the mixture formed by the cracked heavy oil and the second stream of cracked catalyst. The oil and gas after the reaction in the second riser reactor are then introduced into a fluidized bed reactor along with the catalyst for a reaction. By optimizing the process and using appropriate catalysts, we can selectively convert different feeds, achieving higher propylene and butene yields.

Chinese Patent CN101045667B discloses a combined catalytic conversion method for high-yield light olefins. This method involves contacting a heavy oil feedstock with a regenerated catalyst and, optionally, a carbon-deposited catalyst in a downcomer reactor. At least a portion of the separated products, excluding the light olefins, are introduced into a riser reactor for reaction with the regenerated catalyst. After the riser reaction, the catalyst is introduced into the catalyst pre-lift section of the downcomer reactor, where it mixes with the regenerated catalyst entering the downcomer reactor and then contacts the heavy oil feedstock. This method utilizes a combined reactor configuration, with the heavy oil feedstock reacting in the downcomer reactor and the intermediate olefins reacting in the riser reactor, to improve light olefin yields.

Chinese Patent CN109370644A discloses a method for catalytic cracking of crude oil to produce light olefins and aromatics. This method separates crude oil into light and heavy components at a cut point between 150°C and 300°C. The light and heavy fractions react in different reaction zones of the same reactor. The catalyst primarily comprises a silicate-aluminate composed of silicon dioxide and aluminum trioxide, along with alkaline metal oxides, alkaline earth metal oxides, titanium and iron oxides, and vanadium and nickel oxides. This method, based on a dense-phase transported-bed reactor for the catalytic cracking of heavy oil to produce light olefins, offers a solution for producing light olefins through the catalytic cracking of crude oil.

These methods involve developing novel reactor structures, researching new catalytic materials, and controlling reaction depth to improve propylene selectivity. These methods have led to the development of catalytic cracking methods for producing light olefins and aromatics. However, there are currently no preparation methods or reactor structures specifically designed to maximize the production of chemical feedstocks from crude oil.

The purpose of this disclosure is to develop an apparatus and method suitable for processing hydrocarbon-containing feedstock oils for catalytic cracking, taking into account the different hydrocarbon compositions and cutting temperatures of various hydrocarbon-containing feedstock oils, to maximize the utilization of these feedstock oils for the production of light olefins and BTX.

To achieve the above objectives, the present disclosure provides a method for producing light olefins and light aromatics by catalytic cracking of hydrocarbon-containing feedstock oil. The method comprises the following steps: S1. Cutting the hydrocarbon-containing feedstock oil into a light oil fraction and a heavy oil fraction, wherein the weight ratio of the light oil fraction to the heavy oil fraction (light oil fraction/heavy oil fraction) is X; S2. Introducing the light oil fraction and a first stream of catalyst into a first downward reactor to perform a first catalytic cracking to obtain a material after the first catalytic cracking; and optionally, S2'. The material after the first catalytic cracking is introduced into a fluidized bed reactor for a second catalytic cracking to obtain a material after the second catalytic cracking; S3, the material after the first catalytic cracking is subjected to gas-solid separation to obtain a first reaction oil gas and a first spent catalyst, or the material after the second catalytic cracking is subjected to gas-solid separation to obtain a second reaction oil gas and a second spent catalyst; S4, the continuous catalyst, the heavy oil and the second stream of catalyst are introduced into a second upward reactor for a third catalytic cracking. , and then perform gas-solid separation to obtain a third reaction oil gas and a third spent catalyst; the continuous catalyst is at least a portion of the first spent catalyst or at least a portion of the second spent catalyst; the weight ratio of the second catalyst to the continuous catalyst (second catalyst/continuous catalyst) is R; S5, from any one of the first reaction oil gas, the second reaction oil gas and the third reaction oil gas, or a mixture of the first reaction oil gas and the third reaction oil gas, or the second reaction oil gas Light olefins and light aromatics are separated from the mixture of the gas and the third reaction oil gas, and a light olefin fraction is separated. The light olefin fraction is returned to the second upward reactor in step S4 or the fluidized bed reactor in step S2'. 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 of the second catalyst when it enters step S4 (unit: °C), and T3 is the outlet temperature of the second upward reactor (unit: °C).

Optionally, in the method disclosed herein, the outlet temperature T3 of the second upward reactor is 530-650°C, preferably 560-640°C, more preferably 580-630°C, and even more preferably 600-630°C; and/or the temperature T0 of the second catalyst when entering step S4 is 690-750°C, preferably 700-740°C, more preferably 705-730°C, and even more preferably 710-725°C.

Optionally, in the method disclosed herein, in step S1, the hydrocarbon-containing feedstock oil is cut into a light oil fraction and a heavy oil fraction at a cutting point of any temperature between 100°C and 400°C, such that the weight ratio of the light oil fraction to the heavy oil fraction (light oil fraction/heavy oil fraction) is X.

Optionally, in the method disclosed herein, in the first down-flow reactor, the conditions for the first catalytic cracking include: the outlet temperature of the first down-flow reactor is 610-720°C, the gas-solid residence time is 0.1-3.0 seconds, and the fuel-oil ratio is 15-80; and/or, in the fluidized bed reactor, the conditions for the second catalytic cracking include: the reaction temperature in the fluidized bed reactor is 600-690°C, and the mass space velocity is 2-20h ^-1 ; and/or, in the second up-flow reactor, the conditions for the third catalytic cracking include: the gas-solid residence time is 0.5-8 seconds, and the fuel-oil ratio is 8-40.

Optionally, in the method disclosed herein, in the first down-flow reactor, the conditions for the first catalytic cracking include: the outlet temperature of the first down-flow reactor is 650-690°C, the gas-solid residence time is 0.5-1.5 seconds, and the fuel-oil ratio is 25-65; and/or, in the fluidized bed reactor, the conditions for the second catalytic cracking include: the reaction temperature in the fluidized bed reactor is 640-670°C, and the mass space velocity is 4-12h ^-1 ; and/or, in the second up-flow reactor, the conditions for the third catalytic cracking include: the gas-solid residence time is 1.5-5 seconds, and the fuel-oil ratio is 10-30.

Optionally, in the method disclosed herein, in step S4, the continuous catalyst is first mixed with the second catalyst before a subsequent catalytic cracking reaction is carried out; and/or, if step S2' is present, the separated catalyst is stripped during the gas-solid separation in step S3 to obtain a second spent catalyst; and/or, in step S4, the light olefin fraction from step S5 is contacted with the mixture of the second catalyst and the continuous catalyst before the heavy fraction is contacted with the light olefin fraction to carry out catalytic cracking; preferably, the The light olefins are contacted with the mixture of the second catalyst and the continuous catalyst 0.3-1.0 seconds before the re-distillate oil for catalytic cracking. More preferably, the light olefins are contacted with the mixture of the second catalyst and the continuous catalyst 0.4-0.8 seconds before the re-distillate oil for catalytic cracking. And/or, the method comprises a step S0 before step S1, wherein the hydrocarbon-containing feedstock oil is desalinated and dehydrated, and the dehydrated and desalted hydrocarbon-containing feedstock oil is introduced into step S1 for cutting.

Optionally, in the method disclosed herein, the method further comprises: in the gas-solid separation of step S4, stripping the separated catalyst to obtain a third spent catalyst; and/or, regenerating the third spent catalyst and optionally the first spent catalyst or the second spent catalyst that has not entered the second upward reactor by burning at a temperature of 690-750°C, preferably 700-740°C, further preferably 705-730°C, and further preferably 710-725°C to obtain a regenerated catalyst; and/or, any one of the first reaction oil and gas, the second reaction oil and gas, and the third reaction oil and gas, or a mixture of the first reaction oil and gas and the third reaction oil and gas, or the second reaction oil and gas and the mixture of the first reaction oil and gas and the third reaction oil and gas to obtain dry gas, C3 fraction, C4 fraction, light gasoline, heavy gasoline, diesel and oil slurry, from which light olefins and light aromatics are separated, and the light olefin fraction is separated; and/or, when step S2' does not exist, in step S5, from the mixture of either the first reaction oil and gas, the third reaction oil and gas or both The light olefin distillate fraction is separated from the mixture and returned to the second ascending reactor in step S4. If step S2' is present, in step S5, the light olefin distillate fraction is separated from either the second reaction oil gas or the third reaction oil gas, or a mixture of both, and returned to the fluidized bed reactor in step S2'.

Optionally, in the method disclosed herein, the hydrocarbon-containing feedstock oil is one of crude oil, coal liquefaction oil, synthetic oil, oil sands oil, shale oil, tight oil, and animal and vegetable oils or fats, or a mixture of two or more thereof, or a hydrogenated and reformed oil of a partial distillate or a heavy distillate of each of these.

Optionally, in the method disclosed herein, the first catalyst and the second catalyst each independently comprise an active component and a carrier, wherein the active component is at least one selected from ultrastable Y-type zeolite containing or not containing rare earth elements, ZSM-5 series zeolites, high-silica zeolites with a pentacyclic structure, and beta zeolite, and the carrier is at least one selected from aluminum oxide, silicon oxide, amorphous silica-aluminum, zirconium oxide, titanium oxide, boron oxide, and alkaline earth metal oxides.

Optionally, in the method disclosed herein, the first catalyst and the second catalyst each independently comprise a regeneration catalyst. Preferably, the first catalyst and the second catalyst are regeneration catalysts, and/or the entire first spent catalyst or the entire second spent catalyst is used as a continuous catalyst.

The present disclosure also provides a device for producing light olefins and light aromatics by catalytic cracking of hydrocarbon-containing feedstock oil, the device comprising the following units: a hydrocarbon-containing feedstock oil cutting unit, in which the hydrocarbon-containing feedstock oil is cut into light distillate oil and heavy distillate oil, so that the weight ratio of the light distillate oil to the heavy distillate oil (light distillate oil/heavy distillate oil) is X; a first downward reaction unit, in which the light distillate oil and a first stream of catalyst are introduced from the top of the reaction unit to perform a first catalytic cracking, and a material after the first catalytic cracking is obtained at the bottom of the reaction unit; an optional fluidized bed reaction unit; a first gas-solid separation unit, wherein the material after the first catalytic cracking is introduced and subjected to a second catalytic cracking to obtain a second catalytic cracking material; a first gas-solid separation unit, wherein the material after the first catalytic cracking is introduced and subjected to a gas-solid separation to obtain a first reaction oil gas and a first spent catalyst, or a second gas-solid separation unit, wherein the material after the second catalytic cracking is introduced and subjected to a gas-solid separation to obtain a second reaction oil gas and a second spent catalyst; and a second upward reaction unit, wherein a continuous catalyst, a second stream of catalyst, and the heavy oil are introduced from the bottom of the reaction unit to perform a third catalytic cracking. A material after the third catalytic cracking is obtained above the reaction unit. The continuous catalyst is at least a portion of the first spent catalyst or at least a portion of the second spent catalyst. The weight ratio of the second catalyst to the continuous catalyst (second catalyst/continuous catalyst) is R. A second gas-solid separation unit is provided, wherein the material after the third catalytic cracking is introduced for gas-solid separation to obtain a third reaction oil and gas and a third spent catalyst. A separation unit is provided, wherein the first reaction oil and gas, the second reaction oil and gas, and the third reaction oil and gas are introduced. Either one, or a mixture of the first reaction oil and gas and the third reaction oil and gas, or a mixture of the second reaction oil and gas and the third reaction oil and gas, separates light olefins and light aromatics, and separates a light olefin distillate, and returns the light olefin distillate to the second upward reaction unit or the fluidized bed reaction unit; wherein 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 of the second catalyst when it enters the second upward reaction unit (unit: °C), and T3 is the outlet temperature of the second upward reaction unit (unit: °C).

Optionally, the apparatus disclosed herein further includes a regeneration unit, wherein the third spent catalyst and any of the first spent catalyst or the second spent catalyst that has not entered the second ascending reactor are introduced and coked and regenerated at a temperature of 690-750°C, preferably 700-740°C, more preferably 705-730°C, and even more preferably 710-725°C, to produce a regenerated catalyst.

Optionally, in the apparatus disclosed herein, when the apparatus includes a fluidized bed reaction unit, the first gas-solid separation unit further includes 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 includes a stripping unit, in which the catalyst obtained by gas-solid separation is stripped to obtain a third spent catalyst.

Optionally, the apparatus disclosed herein further comprises a dehydration and desalination unit, wherein the hydrocarbon-containing feedstock oil is subjected to a desalination and dehydration treatment, and the dehydrated and desalted hydrocarbon-containing feedstock oil is introduced into a hydrocarbon-containing feedstock oil cutting unit for cutting.

Optionally, in the apparatus disclosed herein, in the second upward reaction unit, the position for introducing the continuous catalyst and the second stream of catalyst is upstream of the feed port for the light olefin distillate.

Optionally, in the apparatus disclosed herein, in the second upward reaction unit, the feed port for the light olefin fraction from the separation unit is upstream of the feed port for the heavy olefin fraction.

Technical Effects

In this disclosure, the aforementioned specific method is used to split hydrocarbon-containing feedstock into light and heavy fractions based on the hydrocarbon composition and cracking reaction characteristics of different fractions. The light fraction is then cracked in a descending reactor at high temperature and short residence time, resulting in the highly selective production of light olefins and BTX while significantly reducing methane production. Furthermore, the heavy fraction is optimized by utilizing an ascending reactor to maximize the production of light olefins and BTX.

In addition, by installing a fluidized bed reactor below the first down-type reactor, the light olefins in the catalytic cracking material can be further converted, maximizing the production of light olefins.

In this disclosure, the residence time of the light distillate in the first down-flow reactor is short, resulting in low coke production and high yields of light olefins and BTX. Furthermore, the light olefin distillate is further converted in the fluidized bed reactor. As a result, the first spent catalyst exiting the first down-flow reactor or the second spent catalyst exiting the fluidized bed reactor still has relatively high activity and is loaded with carbon deposits. When this catalyst is used in the catalytic cracking of the heavy distillate in the second up-flow reactor, the light olefin yield is increased and the formation of dry gas and coke is suppressed.

More importantly, by ensuring that the weight ratio (X) of the cut light and heavy fractions satisfies a specific relationship with the weight ratio (R) of the second catalyst to the continuous catalyst, the cut ratio can be flexibly adjusted based on the type of hydrocarbon-containing feedstock. Accordingly, the weight ratio of the second catalyst to the continuous catalyst can be adjusted accordingly, resulting in a more consistent match between the catalyst activity and the composition of the heavy fraction in the second ascending reactor. This maximizes the production of light olefins and BTX while significantly reducing the yields of by-products such as dry gas and coke.

Furthermore, through the above-mentioned technical solution, the method for producing light olefins and BTX by catalytic cracking of hydrocarbon-containing feedstock provided in this disclosure can significantly improve the yield of light olefins and light aromatics and the economic efficiency of the equipment.

Other features and advantages of this disclosure will be described in detail in the subsequent specific implementation section.

1: Downstream Reactor

11: Light oil feed nozzle

12: First stream of catalyst (regenerated catalyst) delivery pipe

13: Mushroom head distributor

2: Fluidized bed reactor

21: Light olefin distillate feed nozzle

22: First reaction oil and gas outlet/Second reaction oil and gas outlet

3: Upstream Reactor

31: Continuous catalyst delivery pipe

32: Second catalyst (regeneration catalyst) delivery pipe

33: Heavy oil feed nozzle

4: Sedimenter

41: Third Reactor Oil and Gas Outlet

5: Stripper

51: First Stripper

52: Second stripper

53: Third spent catalyst delivery pipe

6: Regenerator

7: Gas-solid separator

The accompanying drawings are used to provide a further understanding of this disclosure and constitute part of the specification. Together with the specific embodiments below, they are used to explain this disclosure but do not constitute a limitation of this disclosure. In the accompanying drawings: Figure 1 is a schematic diagram of an embodiment of the device of this disclosure.

Figure 2 is a schematic diagram of another embodiment of the device disclosed herein.

The following describes in detail the specific implementations of this disclosure. It should be understood that the specific implementations described herein are only used to illustrate and explain this disclosure and are not intended to limit this disclosure.

Any specific numerical value disclosed herein (including the endpoints of a numerical range) is not limited to the exact value of that value, but should be understood to also cover values close to that exact value, such as all possible numerical values within ±5% of that exact value. Furthermore, for a disclosed numerical range, any combination of the endpoints of the range, the endpoints and specific points within the range, and the specific points within the range may be used to form one or more new numerical ranges. These new numerical ranges should also be considered specifically disclosed herein.

Unless otherwise specified, the terms used herein have the same meanings as commonly understood by those skilled in the art. If a term is defined herein and its definition differs from the commonly understood meaning in the art, the definition in this document shall prevail.

Except as expressly stated herein, any matters or items not mentioned herein are directly applicable to those known in the art without modification. Furthermore, any embodiment described herein may be freely combined with one or more other embodiments described herein. The resulting technical solutions or concepts are considered part of the original disclosure or original record of this disclosure and should not be construed as new content not previously disclosed or anticipated herein, unless a person skilled in the art deems such combination manifestly unreasonable.

The present disclosure provides a method for producing light olefins and light aromatics by catalytic cracking of hydrocarbon-containing raw oil, the method comprising the following steps: S1, cutting the hydrocarbon-containing raw oil into a light oil fraction and a heavy oil fraction, wherein the weight ratio of the light oil fraction to the heavy oil fraction (light oil fraction/heavy oil fraction) is X; S2, introducing the light oil fraction and a first stream of catalyst into a first down-type reactor to perform a first catalytic cracking to obtain a material after the first catalytic cracking; and optionally, S2', introducing the first catalytic cracking into a first reactor to perform a first catalytic cracking to obtain a material after the first catalytic cracking. The material after the first catalytic cracking is introduced into a fluidized bed reactor for a second catalytic cracking to obtain a material after the second catalytic cracking; S3, the material after the first catalytic cracking is subjected to gas-solid separation to obtain a first reaction oil gas and a first spent catalyst, or the material after the second catalytic cracking is subjected to gas-solid separation to obtain a second reaction oil gas and a second spent catalyst; S4, the continuous catalyst, the heavy oil and the second catalyst are introduced into a second upward reactor for a third catalytic cracking, and then gasification is carried out. solid separation to obtain a third reaction oil gas and a third spent catalyst; the continuous catalyst is at least a portion of the first spent catalyst or at least a portion of the second spent catalyst; the weight ratio of the second catalyst to the continuous catalyst (second catalyst/continuous catalyst) is R; S5, from any one of the first reaction oil gas, the second reaction oil gas and the third reaction oil gas, or a mixture of the first reaction oil gas and the third reaction oil gas, or the second reaction oil gas and the third reaction oil gas, Light olefins and light aromatics are separated from the mixture of the three-reaction oil and gas, and a light olefin fraction is separated. The light olefin fraction is returned to the second upward reactor in step S4 or the fluidized bed reactor in step S2'. 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 of the second catalyst when it enters step S4 (unit: °C), and T3 is the outlet temperature of the second upward reactor (unit: °C).

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

In this disclosure, light olefins refer to ethylene, propylene, butene, and their isomers. Light aromatics refer to BTX, namely benzene, toluene, and xylene. In this disclosure, light olefins can be separated from dry gas, C3 distillate, and C4 distillate; light aromatics can be separated from light gasoline and heavy gasoline.

In this disclosure, C3 distillates refer to hydrocarbons with three carbon atoms in the reaction oil and gas, including propane and propylene; C4 distillates refer to hydrocarbons with four carbon atoms in the reaction oil and gas, including butane, butene, and their isomers; light gasoline refers to all or part of the distillates in the reaction oil and gas with a distillation range of 30-90°C, where "partial distillates" refers to distillates with a temperature range of part of the 30-90°C range (for example, distillates with a distillation range of 30-60°C, 40-60°C, or 60-90°C); heavy gasoline refers to the distillates in the reaction oil and gas with a distillation range of 30-200°C, excluding light gasoline.

In this disclosure, the terms "light oil fraction" and "heavy oil fraction" refer to the light fraction obtained by cutting a hydrocarbon-containing feedstock oil at a certain cutting temperature. The remaining fraction is referred to as the heavy oil fraction, while the remaining fraction is referred to as the light oil fraction. Those skilled in the art can cut the hydrocarbon-containing feedstock oil as needed using methods known in the art (including but not limited to fractionation and distillation), as long as the weight ratio of the light oil fraction to the heavy oil fraction (light oil fraction/heavy oil fraction) is X, and X satisfies the following relationship in this disclosure. In one embodiment of the present disclosure, X is between any two 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, and 10.0. In one embodiment of the present disclosure, X is 0.1-2.0, preferably 0.12-1.0, and more preferably 0.15-0.6.

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

In this disclosure, the hydrocarbon-containing feedstock oil can be any of various feedstock oils known in the art (herein, hydrocarbon-containing feedstock oil is sometimes referred to as simply feedstock oil), for example, 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 or plant oils and fats, or a fraction thereof, or a hydro-reformed oil of a heavy fraction thereof. In one embodiment of this disclosure, the hydrocarbon-containing feedstock oil is preferably crude oil, a fraction of crude oil, or a hydro-reformed oil of a heavy oil derived from crude oil. As is known to those skilled in the art, the "fraction" can be obtained by subjecting the feedstock oil to conventional processing methods, including but not limited to atmospheric distillation or reduced pressure distillation. Those skilled in the art can determine the method of such conventional processing as needed. In one embodiment of the present disclosure, crude oil can be used as the hydrocarbon-containing feedstock oil. Alternatively, the crude oil can be subjected to atmospheric or reduced pressure distillation, and the remaining fraction (partial distillate of the crude oil) can be extracted as the hydrocarbon-containing feedstock oil. Alternatively, the product of heavy oil derived from crude oil through hydroreforming (hydroreformed heavy oil) can be used as the hydrocarbon-containing feedstock oil. As is known in the art, hydroreforming includes, but is not limited to, hydrodesulfurization, hydrodenitrogenation, hydrodemetallization, and hydrosaturation.

In one embodiment of the present disclosure, the method includes step S0 before step S1, wherein the hydrocarbon-containing feedstock oil is desalinated and dehydrated, and the dehydrated and desalted hydrocarbon-containing feedstock oil is introduced into step S1 for cutting.

According to the present disclosure, in step S2, in the first down-flow reactor, the first catalytic cracking conditions include: an outlet temperature of 610-720°C, preferably 650-690°C. The first catalytic cracking conditions also include: a gas-solid residence time of 0.1-3.0 seconds, preferably 0.5-1.5 seconds. The catalyst-to-oil ratio of the catalyst to the light oil in the first down-flow reactor can be a commonly used catalyst-to-oil ratio in catalytic cracking (calculated as a weight ratio of catalyst to light oil), for example, 15-80, preferably 25-65.

In this disclosure, there is no limitation on the method for introducing the light distillate and the first catalyst into the first down-flow reactor. The light distillate and the first catalyst can be introduced at the upper end of the first down-flow reactor. Preferably, the light distillate and the first catalyst are introduced through different feed ports of the first down-flow reactor.

In this disclosure, the first catalyst is not limited and can be any catalyst known in the art for catalytic cracking of crude oil. For example, the first catalyst can include an active component and a carrier, wherein the active component is at least one selected from ultrastable Y-type zeolite with or without rare earth elements, ZSM-5 series zeolites, high-silica zeolites with a pentacyclic structure, and beta zeolite. The carrier is at least one selected from alumina, silica, amorphous silica-alumina, zirconium oxide, titanium oxide, boron oxide, and alkaline earth metal oxides.

In one embodiment of the present disclosure, the structure of the first down-flow reactor is not particularly limited, as long as it can achieve material feeding from the top and material discharge from the bottom. For example, it can be a down-flow tube reactor with a constant diameter or a variable diameter.

In this disclosure, since no additional heat source is used in the first downer reactor, the outlet temperature of the first downer reactor reflects the reaction temperature within the reactor. In this disclosure, the degree of catalytic cracking of the light distillate in the first downer reactor can be adjusted by adjusting factors such as the temperature of the first stream of catalyst, the gas-solid residence time in the reactor, and the outlet temperature of the first downer reactor.

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

In this disclosure, there is no particular limitation on the temperature of the first stream of catalyst entering the downstream reactor, as long as it can undergo catalytic cracking upon contact with the light distillate fraction and meets the first catalytic cracking conditions described in this disclosure. When a regenerated catalyst is used as the first stream of catalyst, the first stream of catalyst is fed directly from the regenerator via a first stream of catalyst (regenerated catalyst) feed pipe. Because the feed pipe between the regenerator and the first downstream reactor is short, the temperature of the first stream of catalyst can be considered the temperature of the regenerator or the temperature of the regenerated catalyst upon leaving the regenerator (the temperature at the regenerator outlet). In one embodiment of the present disclosure, the temperature of the first stream of catalyst entering the downdraft reactor is the temperature of the regenerator or the temperature of the regenerated catalyst upon leaving the regenerator (the temperature at the regenerator outlet), typically 690-750°C, preferably 700-740°C, more preferably 705-730°C, and even more preferably 710-725°C. Furthermore, the catalyst from the regenerator can be further heated or cooled, as needed, before being fed to the first downdraft reactor. In the method of the present disclosure, during operation, fresh catalyst can be heated to the desired temperature before being introduced into the first downdraft reactor; thereafter, the regenerated catalyst from the regenerator can be used 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.

In the present disclosure, the light oil fraction may be preheated as needed before being introduced into the first downdraft reactor. The temperature of the preheated light oil fraction is, for example, 30-100°C. Alternatively, the light oil fraction may be atomized using water vapor before being introduced into the first downdraft reactor using water vapor as a carrier.

In this disclosure, the materials after the first catalytic cracking process include the first reaction oil gas obtained by catalytic cracking the light distillate and the first spent catalyst obtained by coking (carbonizing) the first stream of catalyst. This first spent catalyst still has a high level of activity and is loaded with carbon deposits. When introduced as a continuous catalyst into the subsequent second upward reactor, it facilitates the catalytic cracking of the heavy distillate, increases the yield of light olefins, and suppresses the formation of dry gas and coke.

In this disclosure, in step S3, the material after the first catalytic cracking is subjected to gas-solid separation to obtain a first reaction oil gas and a first spent catalyst. The method for gas-solid separation is not particularly limited and can be implemented by methods known in the art, such as using a settler or cyclone separator to separate the catalyst from the first reaction oil gas.

In one embodiment of the present disclosure, the first reaction gas is separated to obtain dry gas, a C3 fraction, a C4 fraction, light gasoline, heavy gasoline, diesel, and oil slurry. Light olefins and light aromatics are separated from these fractions, and a light olefin fraction is also separated. The C4 fraction and/or light gasoline constitute the light olefin fraction. In one embodiment of the present disclosure, the first reaction gas is introduced into a distillation device or a gas separator for distillation to achieve the above separation. In one embodiment of the present disclosure, the light olefin fraction is introduced into the second ascending 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 the second ascending reactor described below. In another embodiment of the present disclosure, the first spent catalyst that does not enter the second ascending reactor is introduced into a regeneration step, where the catalyst is regenerated. Preferably, the entire first spent catalyst is introduced into the second ascending reactor as a continuous catalyst, in which case the amount of the first spent catalyst serving as the continuous catalyst substantially corresponds to the amount of the first 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 stripped to remove adsorbed hydrocarbon products, thereby obtaining a first spent catalyst.

In one embodiment of the present disclosure, step S2' may be included after step S2 and before step S3, wherein the material after the first catalytic cracking is introduced into a fluidized bed reactor for a second catalytic cracking to obtain a material after the second catalytic cracking. This further converts the light olefin fraction and maximizes the production of light olefins.

In this disclosure, a "fluidized bed reactor" is also referred to as a "fluidized reactor" and has a catalyst density between 150 and 450 kg/ ^m3 .

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

According to one embodiment of the present disclosure, the fluidized bed reactor directly introduces the material after the first catalytic cracking process for catalytic cracking without introducing new catalyst. According to one embodiment of the present disclosure, the fluidized bed reactor directly utilizes the heat of the material after the first catalytic cracking process without applying an additional heat source. The introduced material after the first catalytic cracking process includes the first reaction oil gas obtained by catalytic cracking the light distillate fraction and the first spent catalyst obtained by coking (carbonizing) the first catalyst stream. This first spent catalyst still has a high level of activity, allowing the catalytic cracking process to continue intensifying in the fluidized bed reactor, further converting the light olefin fraction into lower olefins.

According to one embodiment of the present disclosure, a light olefin fraction is separated from the reaction oil and gas, and the light olefin fraction is returned to the fluidized bed reactor for further conversion into light olefins. More specifically, the reaction oil and gas are separated to obtain dry gas, a C3 fraction, a C4 fraction, light gasoline, heavy gasoline, diesel, and oil slurry, from which light olefins and light aromatics are separated, and the light olefin fraction is separated. The C4 fraction and/or light gasoline constitute the light olefin fraction. In one embodiment of the present disclosure, the reaction oil and gas are introduced into a distillation device or a gas separation device to achieve the above separation.

In this disclosure, the materials after the second catalytic cracking process include the second reaction oil and gas and a second spent catalyst. This second spent catalyst still has a high level of activity and is loaded with carbon deposits. When introduced as a continuous catalyst into the subsequent second upward reactor, it facilitates the catalytic cracking of the heavy distillate, increases the yield of light olefins, and suppresses the formation of dry gas and coke.

In this disclosure, in step S3, the material after the second catalytic cracking is subjected to gas-solid separation to obtain a second reaction oil gas and a second spent catalyst. The method for gas-solid separation is not particularly limited and can be implemented by methods known in the art, such as using a settler or cyclone separator to separate the catalyst from the second reaction oil gas.

In one embodiment of the present disclosure, the second reaction oil and gas are separated to obtain dry gas, a C3 distillate, a C4 distillate, light gasoline, heavy gasoline, diesel, and oil slurry. From these, light olefins and light aromatics are separated, and a light olefin distillate is also separated. The C4 distillate and/or light gasoline constitute the light olefin distillate. In one embodiment of the present disclosure, the second reaction oil and gas are introduced into a distillation device or a gas separation device to achieve the above separation.

In one embodiment of the present disclosure, the material after the second catalytic cracking is subjected to gas-solid separation. The separated catalyst is further stripped to remove adsorbed hydrocarbon products, thereby obtaining a second spent catalyst. In the present disclosure, at least a portion of the second spent catalyst is introduced as a continuous catalyst into the second upward reactor described below.

In one embodiment of the present disclosure, the second spent catalyst that has not entered the second ascending reactor is introduced into a regeneration step, where the catalyst is regenerated. Preferably, the entire second spent catalyst is introduced into the second ascending reactor as a continuous stream catalyst, with the amount of the second spent catalyst serving as the continuous stream catalyst substantially corresponding to the amount of the first stream catalyst.

In this disclosure, in step S4, a continuous catalyst, the heavy oil fraction, and a second stream of catalyst are introduced into a second ascending reactor for a third catalytic cracking process, followed by gas-solid separation, to produce a third reaction oil gas and a third spent catalyst. The continuous catalyst is at least a portion of the first spent catalyst or at least a portion of the second spent catalyst.

In one embodiment of the present disclosure, the conditions for the third catalytic cracking in the second ascending reactor include: an outlet temperature T3 of 530-650°C, preferably 560-640°C, more preferably 580-630°C, and even more preferably 600-630°C. The conditions for the third catalytic cracking also include: a gas-solid residence time of 0.5-8 seconds, preferably 1.5-5 seconds. The catalyst-to-oil ratio of the catalyst to the heavy oil in the second ascending reactor can be a commonly used catalyst-to-oil ratio for catalytic cracking (calculated by weight ratio of catalyst to heavy oil), for example, 8-40, preferably 10-30.

In one embodiment of the present disclosure, in step S4, the continuous catalyst is first mixed with the second stream of catalyst before the subsequent catalytic cracking reaction is carried out. More specifically, in one embodiment of the present disclosure, the continuous catalyst and the second stream of catalyst are independently fed to the bottom of a second ascending reactor and mixed. The mixed catalyst (hereinafter sometimes referred to as a catalyst mixture or mixed catalyst) is used in the catalytic cracking reaction in the second ascending reactor. In one embodiment of the present disclosure, after the continuous catalyst and the second stream of catalyst are mixed in the bottom region of the second ascending reactor, the mixed catalyst is lifted in the second ascending reactor using a pre-lifting medium to carry out the 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 catalyst is not limited and can be any catalyst known in the art for catalytic cracking of crude oil. For example, the second catalyst comprises an active component and a carrier, wherein the active component is at least one selected from ultrastable Y-type zeolite containing or not containing rare earth elements, ZSM-5 series zeolites, high-silica zeolites with a pentacyclic structure, and beta zeolite. The carrier is at least one selected from aluminum oxide, silicon oxide, amorphous silica-aluminum, zirconium oxide, titanium oxide, boron oxide, and alkaline earth metal oxides.

In one embodiment of the present disclosure, the structure of the second upward reactor is not particularly limited, as long as it can achieve feeding from the bottom and discharging from the top. For example, it can be a riser reactor with a constant diameter or a variable diameter, a riser reactor with a constant diameter or a variable diameter, and a fluidized bed reactor.

In one embodiment of the present disclosure, the second catalyst is fresh catalyst. In one embodiment of the present disclosure, the second catalyst comprises regenerated catalyst from a regenerator. In one embodiment of the present disclosure, the second catalyst is regenerated catalyst from a regenerator. When using fresh catalyst as the second catalyst, the catalyst must be preheated so that the temperature of the fresh catalyst when entering step S4 satisfies the relationship described in this disclosure. Preferably, the second catalyst is regenerated catalyst from a regenerator.

In this disclosure, the weight ratio of the second catalyst to the continuous catalyst (second catalyst/continuous catalyst) is R, and 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 of the second catalyst when it enters step S4 (unit: °C), and T3 is the outlet temperature of the second upward reactor (unit: °C).

The inventors of the present disclosure surprisingly discovered that by ensuring that the cut ratio of the light and heavy fractions of the hydrocarbon-containing feedstock in step S1 (the weight ratio of the light fraction/heavy fraction) and the weight ratio of the second catalyst to the continuous catalyst (the second catalyst/continuous catalyst) satisfy the above-mentioned relationship, the hydrocarbon-containing feedstock composition, the cut ratio, and the catalyst activity (particularly the catalyst activity in the second upward reactor) can be better matched, thereby maximizing the production of light olefins and BTX while significantly reducing the yields of dry gas and coke. Without being bound by any theory, the inventors of the present disclosure speculate that the catalyst used as the continuous catalyst comes from the first spent catalyst or the second spent catalyst. Since the coke generation in the first down-flow reactor and the fluidized bed reactor is low, the first spent catalyst and the second spent catalyst have high catalytic activity and carry a certain amount of carbon deposits. This catalyst is mixed with the second catalyst in a certain ratio. By mixing fresh catalyst or regenerated catalyst from a regenerator, and matching the mixing ratio with the hydrocarbon feedstock cut ratio to satisfy the aforementioned relationship described in this disclosure, the resulting catalyst maintains excellent catalytic activity while avoiding excessive coking of the heavy fraction due to excessive catalyst activity, and insufficient catalytic cracking of the heavy fraction due to insufficient catalyst activity. In this disclosure, the ratio of the hydrocarbon feedstock cut into light and heavy fractions and the mixing ratio of the continuous catalyst and the second stream catalyst are specifically matched. The activity of the mixed catalyst in the second upward reactor can be adjusted based on the hydrocarbon feedstock composition, cut ratio, and other factors, maximizing the yield of light olefins and BTX from the heavy fraction.

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 this disclosure, T0 is the temperature of the second stream of catalyst when it enters step S4. Specifically, it refers to the temperature of the second stream of catalyst (fresh catalyst or regenerated catalyst) when it enters the second ascending reactor, that is, its temperature upon entering the bottom of the second ascending reactor and before mixing with the continuous catalyst. When regenerated catalyst is used as the second stream of catalyst, due to the short transfer line between the regenerator and the second ascending reactor, the temperature of the regenerator or the temperature of the catalyst when the regenerated catalyst exits the regenerator (the temperature at the regenerator outlet) can be considered the temperature of the second stream of catalyst when it enters step S4.

In one embodiment of the present disclosure, the outlet temperature T3 of the second upward reactor is 530-650°C, preferably 560-640°C, more preferably 580-630°C, and even more preferably 600-630°C; and/or the temperature T0 of the second catalyst when entering step S4 is 690-750°C, preferably 700-740°C, more preferably 705-730°C, and even more preferably 710-725°C.

In one embodiment of the present disclosure, the third reaction oil and gas are separated to obtain dry gas, a C3 distillate, a C4 distillate, light gasoline, heavy gasoline, diesel, and oil slurry. From these, light olefins and light aromatics are separated, and a light olefin distillate is also separated. The C4 distillate and/or light gasoline constitute the light olefin distillate. In one embodiment of the present disclosure, the third reaction oil and gas are introduced into a distillation unit or a gas separation unit to achieve the above separation.

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

In this disclosure, when step S2' is present, in step S5, light olefins and light aromatics are separated from either the second reaction oil gas or the third reaction oil gas, or a mixture of both, 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 olefins fraction from step S5 described below is contacted with the catalyst mixture before the heavy olefins fraction to undergo a catalytic cracking reaction. The heavy olefins fraction is then contacted with the catalyst mixture to undergo a catalytic cracking reaction. Preferably, the light olefins fraction is contacted with the catalyst mixture 0.3-1.0 seconds before the heavy olefins fraction. More preferably, the light olefins fraction is contacted with the catalyst mixture 0.4-0.8 seconds before the heavy olefins fraction.

In one embodiment of the present disclosure, the products of the third catalytic cracking process are subjected to gas-solid separation to obtain third reaction oil and gas and a third spent catalyst. The method for gas-solid separation is not particularly limited and can be implemented by methods known in the art, such as using a settler or cyclone separator to separate the catalyst from the third reaction oil and gas.

In one embodiment of the present disclosure, the material after the third catalytic cracking is subjected to gas-solid separation. The separated catalyst is further stripped to remove adsorbed hydrocarbon products, thereby obtaining a third spent catalyst. In another embodiment of the present disclosure, the third spent catalyst is passed into a regenerator for catalyst regeneration.

In one embodiment of the present disclosure, the regenerator temperature is a temperature commonly used in the art and may be 690-750°C, preferably 700-740°C, more preferably 705-730°C, and even more preferably 710-725°C. In one embodiment of the present disclosure, the regenerator temperature or the temperature of the catalyst when the regenerated catalyst exits the regenerator (the temperature at the regenerator outlet) can be considered the temperature of the second stream of catalyst when it enters step S4. Therefore, in one embodiment of the present disclosure, the temperature T0 of the second stream of catalyst when it enters step S4 can be 690-750°C, preferably 700-740°C, more preferably 705-730°C, and even more preferably 710-725°C.

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

In the present disclosure, in step S5, light olefins and light aromatics are separated from any one of the first reaction gas, the second reaction gas, and the third reaction gas, or a mixture of the first and third reaction gas, or a mixture of the second and third reaction gas, to obtain light olefins, and a light olefin fraction is separated. The light olefin fraction is then returned to the second upward reactor in step S4 or to the fluidized bed reactor in step S2'. More specifically, the reaction gas is separated to obtain dry gas, a C3 fraction, a C4 fraction, light gasoline, heavy gasoline, diesel, and oil slurry, from which light olefins and light aromatics are separated, and a light olefin fraction is separated. The C4 fraction and/or light gasoline constitute the light olefin fraction. Preferably, the reaction oil gas is introduced into a distillation device or a gas separation device to achieve the above-mentioned separation. In step S5, the first reaction oil gas and the third reaction oil gas can be separated separately or combined and separated together. Alternatively, the second reaction oil gas and the third reaction oil gas can be separated separately or combined and separated together.

In one embodiment of the present disclosure, the method for separating the light olefin fraction from the reaction oil and gas is not limited and can be performed using methods known in the art, including but not limited to the following method: After the reaction oil and gas enter the distillation, absorption and stabilization unit, liquefied gas and stabilized gasoline are separated. The liquefied gas enters the subsequent gas separation device to separate the C3 fraction and the C4 fraction. The stabilized gasoline enters the light and heavy gasoline splitter to separate the light gasoline and heavy gasoline. The C4 fraction and/or light gasoline constitute the light olefin fraction. Light olefins and light aromatics can be separated from it.

In more detail, in one embodiment of the present disclosure, a method for producing light olefins and light aromatics by catalytic cracking of hydrocarbon-containing feedstock oil is provided, the method comprising the following steps: S1, cutting the hydrocarbon-containing feedstock oil into a light oil fraction and a heavy oil fraction, wherein the weight ratio of the light oil fraction to the heavy oil fraction (light oil fraction/heavy oil fraction) is X; S2, introducing the light oil fraction and a first stream of catalyst into a first descending reactor, performing a first catalytic cracking to obtain a material after the first catalytic cracking; S3, performing gas-solid separation on the material after the first catalytic cracking to obtain a first reaction oil gas and a first spent catalyst; S4, introducing a continuous catalyst, the heavy oil fraction and a second stream of catalyst into a second ascending reactor, performing a third catalytic cracking, and then performing a gas-solid separation. solid separation to obtain a third reaction oil gas and a third spent catalyst; the continuous catalyst is at least a portion of the first spent catalyst; the weight ratio of the second catalyst to the continuous catalyst (second catalyst/continuous catalyst) is R; S5, separating light olefins and light hydrocarbons from either the first reaction oil gas and the third reaction oil gas or a mixture of both. Aromatics are separated and a light olefin fraction is returned 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 of the second catalyst when it enters step S4 (unit: °C), and T3 is the outlet temperature of the second upward reactor (unit: °C).

More specifically, in one embodiment of the present disclosure, a method for producing light olefins and light aromatics by catalytic cracking of a hydrocarbon-containing feedstock is provided. The method comprises the following steps: S1. Cutting the hydrocarbon-containing feedstock into a light fraction and a heavy fraction, wherein the weight ratio of the light fraction to the heavy fraction (light fraction/heavy fraction) is X; S2. Introducing the light fraction and a first stream of catalyst into a first downward reaction. The first catalytic cracking reactor is used to perform a first catalytic cracking to obtain a material after the first catalytic cracking; S2', the material after the first catalytic cracking is introduced into a fluidized bed reactor for a second catalytic cracking to obtain a material after the second catalytic cracking; S3, the material after the second catalytic cracking is subjected to gas-solid separation to obtain a second reaction oil gas and a second spent catalyst; S4, the continuous catalyst, the heavy oil and the second stream catalyst are introduced into a second upward reactor for a third catalytic cracking, and then subjected to gas-solid separation to obtain a third reaction oil gas and a third spent catalyst; the continuous catalyst is at least a portion of the second spent catalyst; the weight ratio of the second stream catalyst to the continuous catalyst (second stream catalyst/continuous catalyst) is R; S5, from a mixture of either the second reaction oil gas and the third reaction oil gas or both Light olefins and light aromatics are separated from the mixture, and a light olefin fraction is separated. The light olefin fraction is returned to the fluidized bed reactor in step S2'. 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 of the second catalyst when it enters step S4 (unit: °C), and T3 is the outlet temperature of the second upward reactor (unit: °C).

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

This disclosure also provides the following technical solutions:

A1. A method for producing light olefins and light aromatics by catalytic cracking of hydrocarbon-containing feedstock, the method comprising the following steps: S1. cutting the desalted and dehydrated hydrocarbon-containing feedstock into a light distillate fraction and a heavy distillate fraction; the cutting point is any temperature between 100° C. and 400° C.; S2. introducing the light distillate fraction and a first stream of catalyst into a first down-flow reactor for a first catalytic cracking to obtain a first catalytic cracked material; optionally, S2′, introducing the first catalytic cracked material into a fluidized bed reactor for a second catalytic cracking to obtain a second catalytic cracked material; S3. performing gas-solid separation on the first catalytic cracked material to obtain a first reaction oil gas and a first spent catalyst. Alternatively, the material after the second catalytic cracking is subjected to gas-solid separation to obtain a second reaction oil gas and a second spent catalyst; S4, the continuous catalyst, the heavy distillate oil, and the second stream catalyst are introduced into a second ascending reactor for a third catalytic cracking, followed by gas-solid separation to obtain a third reaction oil gas and a third spent catalyst; the continuous catalyst is the first spent catalyst or the second spent catalyst; the weight ratio of the second stream catalyst to the continuous catalyst is 0.2-5:1; S5, the light olefins fraction is separated from the first reaction oil gas and the second reaction oil gas, and the light olefins fraction is returned to the fluidized bed reactor or the second ascending reactor.

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

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

A4. The method of claim A1, wherein, in the first down-flow reactor, the conditions for the first catalytic cracking include: an outlet temperature of 610-720°C and a gas-solid residence time of 0.1-3.0 seconds; in the fluidized bed reactor, the conditions for the second catalytic cracking include: a reaction temperature of 600-670°C and a mass space velocity of 2-20 h ^-1 in the fluidized bed reactor; and in the second up-flow reactor, the conditions for the third catalytic cracking include: an outlet temperature of 530-650°C and a gas-solid residence time of 0.5-8 seconds.

A5. The method according to A4, wherein, in the first down-flow reactor, the conditions for the first catalytic cracking include: an outlet temperature of 650-690°C and a gas-solid residence time of 0.5-1.5 seconds; in the fluidized bed reactor, the conditions for the second catalytic cracking include: a reaction temperature of 620-640°C and a mass space velocity of 4-12 h ^-1 in the fluidized bed reactor; and in the second up-flow reactor, the conditions for the third catalytic cracking include: an outlet temperature of 560-640°C and a gas-solid residence time of 1.5-5 seconds.

A6. The method according to A1, wherein the light olefins distillate is subjected to catalytic cracking with the second catalyst 0.3-1.0 seconds before the heavy olefins distillate; preferably, the light olefins distillate is subjected to catalytic cracking with the second catalyst 0.4-0.8 seconds before the heavy olefins distillate.

A7. The method according to A1, further comprising: regenerating the third spent catalyst by coking to obtain a regenerated catalyst; separating the first and second oil and gas streams to obtain dry gas, a C3 fraction, a C4 fraction, light gasoline, heavy gasoline, diesel, and oil slurry; the light olefin fraction is the C4 fraction in the first and second oil and gas streams and/or the fraction in the first and second oil and gas streams within a temperature range of 30-90°C.

A8. The method according to A1, wherein the hydrocarbon-containing feedstock oil is one or a mixture of conventional mineral oil, coal liquefaction oil, synthetic oil, oil sands oil, shale oil, tight oil, and animal and vegetable oils and fats.

A9. The method according to A1, wherein the first catalyst and the second catalyst each independently comprise an active component and a carrier, wherein the active component is at least one selected from ultrastable Y-type zeolite containing or not containing rare earth elements, ZSP series zeolites, high-silica zeolites with a pentacyclic structure, and beta zeolite.

A10. The method according to A1, wherein the first catalyst and the second catalyst each independently include the regeneration catalyst.

The present disclosure also provides an apparatus for catalytically cracking hydrocarbon-containing feedstock oil to produce light olefins and light aromatics. The apparatus comprises the following units: a hydrocarbon-containing feedstock oil cutting unit, in which the hydrocarbon-containing feedstock oil is cut into a light fraction and a heavy fraction, such that the weight ratio of the light fraction to the heavy fraction (light fraction/heavy fraction) is X; a first downward reaction unit, in which the light fraction and a first stream of catalyst are introduced from the top of the reaction unit to perform a first catalytic cracking operation, and a material after the first catalytic cracking is obtained at the bottom of the reaction unit; and an optional fluidized bed reaction unit. a unit, wherein the material after the first catalytic cracking is introduced and subjected to a second catalytic cracking to obtain a material after the second catalytic cracking; a first gas-solid separation unit, wherein the material after the first catalytic cracking is introduced and subjected to a gas-solid separation to obtain a first reaction oil gas and a first spent catalyst, or wherein the material after the second catalytic cracking is introduced and subjected to a gas-solid separation to obtain a second reaction oil gas and a second spent catalyst; a second upward reaction unit, wherein a continuous catalyst, a second stream of catalyst and the heavy distillate oil are introduced from the bottom of the reaction unit to perform a third catalytic cracking, A material after the third catalytic cracking is obtained above the reaction unit. The continuous catalyst is at least a portion of the first spent catalyst or at least a portion of the second spent catalyst. The weight ratio of the second catalyst to the continuous catalyst (second catalyst/continuous catalyst) is R. A second gas-solid separation unit is provided, wherein the material after the third catalytic cracking is introduced for gas-solid separation to obtain a third reaction oil and gas and a third spent catalyst. A separation unit is provided, wherein the first reaction oil and gas, the second reaction oil and gas, and the third reaction oil and gas are introduced. Either one, or a mixture of the first reaction oil and gas and the third reaction oil and gas, or a mixture of the second reaction oil and gas and the third reaction oil and gas, separates light olefins and light aromatics, and separates a light olefin distillate, and returns the light olefin distillate to the second upward reaction unit or the fluidized bed reaction unit; wherein 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 of the second catalyst when it enters the second upward reaction unit (unit: °C), and T3 is the outlet temperature of the second upward reaction unit (unit: °C).

In this disclosure, T0 is the temperature (in °C) of the second stream of catalyst upon entering the second ascending reaction unit. Specifically, it refers to the temperature of the second stream of catalyst upon entering the bottom of the second ascending reaction unit, before mixing with the continuous catalyst.

In one embodiment of the present disclosure, the apparatus further includes a regeneration unit, wherein the third spent catalyst and, optionally, the first spent catalyst or the second spent catalyst that did not enter the second ascending reactor are introduced for coke regeneration to produce 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°C, preferably 700-740°C, more preferably 705-730°C, and even more preferably 710-725°C.

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

In one embodiment of the present disclosure, the temperature T0 of the second catalyst when entering the second ascending reaction unit is 690-750°C, preferably 700-740°C, more preferably 705-730°C, and even more preferably 710-725°C.

In one embodiment of the present disclosure, the apparatus further includes a dehydration and desalination unit, wherein the hydrocarbon-containing feedstock oil is desalinated and dehydrated, and the dehydrated and desalted hydrocarbon-containing feedstock oil is introduced into a hydrocarbon-containing feedstock oil cutting unit for cutting.

In one embodiment of the present disclosure, the structure of the first down-flow reactor unit is not particularly limited, as long as it can achieve material feeding from the top and material discharge from the bottom. For example, it can be a down-flow tube reactor with a constant diameter or a variable diameter.

In one embodiment of the present disclosure, when a fluidized bed reaction unit is not present, in a separation unit, light olefins and light aromatics are separated from either the first reaction oil gas or the third reaction oil gas, or a mixture of both, and the separated light olefin fraction is returned to the second upward reaction unit.

In the present disclosure, when a fluidized bed reaction unit is present, in the separation unit, light olefins and light aromatics are separated from either the second reaction oil gas or the third reaction oil gas, or a mixture of both, 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 include equipment known in the art that can achieve gas-solid separation, such as a settler or a cyclone separator.

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

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, wherein the catalyst obtained by gas-solid separation is stripped to remove adsorbed hydrocarbon products therein, thereby obtaining a second spent catalyst. In another embodiment of the present disclosure, the second gas-solid separation unit further includes a stripping unit, wherein the catalyst obtained by gas-solid separation is stripped to remove adsorbed hydrocarbon products therein, thereby obtaining a third spent catalyst.

In one embodiment of the present disclosure, a continuous stream of catalyst and a second stream of catalyst are introduced into the bottom of a second ascending reaction unit, mixed, and then used in a subsequent catalytic cracking reaction.

In one embodiment of the present disclosure, in the second upward reaction unit, the position for introducing the continuous catalyst and the second stream of catalyst is upstream of the light olefin distillate feed port.

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

In one embodiment of the present disclosure, the structure of the second upward reactor is not particularly limited, as long as it can achieve feeding from the bottom and discharging from the top. For example, it can be a riser reactor with a constant diameter or a variable diameter, a riser reactor with a constant diameter or a variable diameter, and a fluidized bed reactor.

In more detail, the present disclosure provides a device for producing light olefins and light aromatics by catalytic cracking of hydrocarbon-containing feedstock oil, the device comprising the following units: a hydrocarbon-containing feedstock oil cutting unit, in which the hydrocarbon-containing feedstock oil is cut into light distillate oil and heavy distillate oil, so that the weight ratio of the light distillate oil to the heavy distillate oil (light distillate oil/heavy distillate oil) is X; a first downward reaction unit, in which the light distillate oil and the first catalyst are introduced from the top of the reaction unit to react with each other. The first catalytic cracking agent is introduced into the reaction unit to perform the first catalytic cracking, and the material after the first catalytic cracking is obtained at the bottom of the reaction unit; the first gas-solid separation unit is introduced into the material after the first catalytic cracking to perform gas-solid separation, and the first reaction oil gas and the first catalyst to be produced are obtained; the second upward reaction unit is introduced into the reaction unit from the bottom of the reaction unit to perform the third catalytic cracking, and the first reaction oil gas and the first catalyst to be produced are obtained at the top of the reaction unit. The material after the third catalytic cracking is introduced into the continuous catalyst, which is at least a portion of the first 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 to introduce the material after the third catalytic cracking for gas-solid separation to obtain a third reaction oil and gas and a third spent catalyst. The separation unit is used to introduce the first reaction oil and gas and the third reaction oil and gas. Separating light olefins and light aromatics from a mixture of either oil or gas, and separating the light olefin fraction, which is then returned to the second upward reaction unit; wherein 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 of the second catalyst when it enters the second upward reaction unit (unit: °C), and T3 is the outlet temperature of the second upward reaction unit (unit: °C).

More specifically, the present disclosure provides a device for producing light olefins and light aromatics by catalytic cracking of hydrocarbon-containing feedstock oil, the device comprising the following units: a hydrocarbon-containing feedstock oil cutting unit, in which the hydrocarbon-containing feedstock oil is cut into a light fraction and a heavy fraction, such that the weight ratio of the light fraction to the heavy fraction (light fraction/heavy fraction) is X; a first downward reaction unit, in which the light fraction and a first stream of catalyst are introduced from the top of the reaction unit to perform a first catalytic cracking process. The first catalytic cracking material is obtained below the reaction unit; the fluidized bed reaction unit introduces the first catalytic cracking material and performs a second catalytic cracking to obtain a second catalytic cracking material; the first gas-solid separation unit introduces the second catalytic cracking material and performs a gas-solid separation to obtain a second reaction oil gas and a second spent catalyst; the second upward reaction unit introduces a continuous catalyst and a second stream of catalyst from the bottom of the reaction unit. The oil is re-diluted and subjected to a third catalytic cracking, and a material after the third catalytic cracking is obtained above the reaction unit. The continuous catalyst is at least a portion 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 to introduce the material after the third catalytic cracking for gas-solid separation to obtain a third reaction oil gas and a third spent catalyst. The separation unit is used to introduce the The second reaction oil gas and the third reaction oil gas, or a mixture of both, are used to separate light olefins and light aromatics, 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 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 of the second catalyst when it enters the second upward reaction unit (unit: °C), and T3 is the outlet temperature of the second upward reaction unit (unit: °C).

The apparatus disclosed herein for producing light olefins and light aromatics by catalytic cracking of hydrocarbon-containing feedstock oil is used to implement the disclosed method for producing light olefins and light aromatics by catalytic cracking of hydrocarbon-containing feedstock oil.

Below, referring to Figures 1 and 2, two implementation methods of this disclosure are described in detail, but this disclosure is not limited thereto.

A specific embodiment of the present disclosure is shown in FIG1 , where a hot first stream of catalyst (regenerated catalyst) is delivered to a first down-flow reactor 1 through a first stream of catalyst delivery pipe (regenerated catalyst delivery pipe) 12 . The light oil fraction is injected into the first down-flow reactor 1 through the feed nozzle 11, where it comes into contact with the first stream of catalyst and undergoes a catalytic cracking reaction. The catalyst and oil/gas separation of the resulting first reaction oil/gas occurs in the gas-solid separator 7. The resulting first reaction oil/gas is introduced into a separation device (not shown) via the oil/gas outlet 22 of the down-flow reactor. The first spent catalyst is introduced into the bottom of the second up-flow reactor 3 as a continuous catalyst via a continuous catalyst delivery pipe 31. The second stream of catalyst (regenerated catalyst) is introduced into the bottom of the second up-flow reactor 3 via a second stream of catalyst delivery pipe (regenerated catalyst delivery pipe) 32. The catalyst mixture of the first spent catalyst (continuous catalyst) and the second stream of catalyst is lifted upward by a pre-lifting medium. The light olefin fraction is injected into the second upward reactor 3 through the light olefin fraction feed nozzle 21, where it contacts the catalyst and reacts. The re-entrained oil is injected into the second ascending reactor 3 through the re-entrained oil feed nozzle 33, where it reacts with the oil-to-liquid mixture from the bottom. After the reaction, the material obtained after the third catalytic cracking is fed into the settler 4. In the settler 4, the third spent catalyst and the third reaction oil gas are separated. The third reaction oil gas enters the separation device (not shown) through the oil and gas outlet 41 of the third reactor. The third spent catalyst enters the stripper 5, where the adsorbed hydrocarbon products are stripped out. The third spent catalyst is then sent to the regenerator 6 via the transfer pipe 53 for regeneration. The regenerated catalyst is returned to the first descending reactor and the second ascending reactor for reuse. The reaction gas (first reaction gas and third reaction gas) is separated in a separation device (preferably a distillation device or a gas separator) to obtain dry gas, C3 distillate, C4 distillate, light gasoline, heavy gasoline, diesel, and oil slurry, from which light olefins and light aromatics are separated. Furthermore, a light olefin distillate is separated from the reaction gas and introduced into the second upward reactor 3 through the light olefin distillate feed nozzle 21.

Another specific embodiment of the present disclosure is shown in Figure 2 . A hot first stream of catalyst (regenerated catalyst) is delivered to a first down-type reactor 1 via a first stream of catalyst delivery pipe (regenerated catalyst delivery pipe) 12. Light oil fraction is injected into the first down-type reactor 1 via a feed nozzle 11, where it contacts the first stream of catalyst and undergoes a catalytic cracking reaction. The resulting first catalytic cracking product is introduced through a mushroom-shaped distributor 13 at the outlet of the first down-type reactor into a fluidized bed reactor 2, where cracking continues. A second catalytic cracking product is produced, which is then cyclonized to produce a second reaction oil gas and a second spent catalyst. The second reaction oil and gas is introduced into a separation device (not shown) through the second reaction oil and gas outlet 22. The second spent catalyst enters the first stripper 51 to strip the adsorbed hydrocarbon products. It is then introduced into the bottom of the second ascending reactor 3 through the continuous catalyst delivery pipe 31 as a continuous catalyst. The second stream of catalyst (regenerated catalyst) is introduced into the bottom of the second ascending reactor 3 through the second stream of catalyst delivery pipe (regenerated catalyst delivery pipe) 32. The catalyst after the second spent catalyst (continuous catalyst) and the second stream of catalyst are mixed is lifted upward through the pre-lifting medium. The heavy oil is injected into the second ascending reactor 3 through the heavy oil feed nozzle 33 to react with the catalyst. After the reaction, the third catalytic cracking material is obtained and enters the settler 4. In the settler 4, the third spent catalyst and the third reaction oil gas are separated. The third reaction oil gas is introduced into the separation device (not shown) through the oil and gas outlet 41 of the third reactor. The third spent catalyst enters the second stripper 52 to strip out the adsorbed hydrocarbon products. The third spent catalyst is then sent to the regenerator 6 for regeneration via the third spent catalyst transfer pipe 53. The regenerated catalyst is returned to the first descending reactor and the second ascending reactor for reuse. The reaction gas (second reaction gas and third reaction gas) is separated in a separation device (preferably a distillation device or a gas separator) to obtain dry gas, C3 distillate, C4 distillate, light gasoline, heavy gasoline, diesel, and oil slurry, from which light olefins and light aromatics are separated. Furthermore, a light olefin distillate is separated from the reaction gas and returned to the fluidized bed reactor 2 through the light olefin distillate feed nozzle 21.

Implementation Examples

The present disclosure is further illustrated below through examples. All raw materials used in the examples are commercially available. The catalytic cracking catalyst used in the examples and comparative examples of this disclosure is industrially produced by the Qilu Branch of Sinopec Catalyst Co., Ltd., under the trade name DMMC-2. This catalyst contains ZSM-5 zeolite with an average pore size of less than 0.7 nm and ultrastable Y-type zeolite. Prior to use, the catalyst was hydrothermally aged at 800°C with saturated steam for 17 hours. The main physicochemical properties of the catalyst are shown in Table 1. The hydrocarbon-containing feedstock oil used in the examples and comparative examples was crude oil from the Jiangsu Oilfield. Its properties are listed in Table 2.

Example 1

The light and heavy fraction cut point of crude oil A processed in this example is 320°C, and the cut ratio (weight ratio of light fraction to heavy fraction) is 0.4.

The test was conducted using a modified medium-sized unit with continuous reaction-regeneration operation, the process flow of which is shown in Figure 1. The 720°C high-temperature regenerated catalyst was introduced from the regenerator into the top of descending reactor 1 via a regeneration inclined tube. The light oil fraction, preheated to 45°C, was atomized with water vapor and then entered descending reactor 1 through a feed nozzle, where it came into contact with the first stream of catalyst for a catalytic cracking reaction. The catalyst-to-oil ratio was 40, the reactor outlet temperature was 665°C, and the gas-solid residence time was 0.8 seconds. The material after the first catalytic cracking was separated into the first reaction oil gas and the first spent catalyst by cyclone separation. The first reaction oil gas entered the separation system, and the entire first spent catalyst was introduced into the bottom of the riser reactor (ascending reactor 3). At the same time, regenerated catalyst (second stream catalyst) at 720°C is introduced from the regenerator via regenerated catalyst delivery pipe 32 into the bottom of ascending reactor 3. The weight ratio of the second stream catalyst to the first stream catalyst (second stream catalyst/first stream catalyst) is 0.25. After the first stream catalyst and the second stream catalyst are mixed at the bottom of ascending reactor 3, the mixed catalyst flows upward under the action of pre-lift steam. Simultaneously, the light olefins fraction, under the medium of atomized water vapor, enters the lower part of ascending reactor 3 through the light olefins fraction feed nozzle, where it reacts with the mixed catalyst. The heavy olefins fraction oil nozzle At 800 mm above the light olefin feed nozzle, the heavy olefin oil is atomized with water vapor and then injected into the riser through the heavy olefin feed nozzle for catalytic cracking. The catalyst-to-oil ratio is 20, the reactor outlet temperature T3 is 610°C, and the gas-solid residence time in the reactor is 1.5 seconds. The catalytic cracking material is introduced into a settler for oil-liquid separation, separating it into third-reaction oil gas and third-spent catalyst. The third-reaction oil gas is introduced into the separation system. The first and third-reaction oil gases are separated into cracked gas, light gasoline, heavy gasoline, diesel, and oil slurry in the separation system. A portion of the light gasoline distillate (distillation range 30-60°C) is returned to ascending reactor 3 as the light olefin distillate through the light olefin distillate feed nozzle. The third spent catalyst enters the stripper, where the hydrocarbon products adsorbed on the spent catalyst are stripped. It then passes through the spent catalyst inclined tube into the regenerator, where it is exposed to air and regenerated by coking at 720°C. The regenerated catalyst returns to the reactor through the regeneration inclined tube for recycling. Medium-sized units use electric heating to maintain the temperature of the reaction-regeneration system. Once the unit is operating stably (with the product composition remaining essentially unchanged), the cracked gas and gasoline compositions obtained from the reaction oil and gas are analyzed to determine the yields of light olefins (hereinafter referred to as trienes) and light aromatics (hereinafter referred to as BTX) in the products.

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

Example 2

The same apparatus and reaction steps as in Example 1 were employed, except that the light/heavy component cutoff point of the processed crude oil A was 250°C, the cutoff ratio (weight ratio of light fraction to heavy fraction) was 0.195, the weight ratio of the second stream catalyst to the first spent catalyst (second stream catalyst/first spent catalyst) was 0.03, the regenerator temperature was 700°C (i.e., the temperature T0 of the second stream catalyst when it entered step S4 was 700°C), and the riser reactor outlet temperature T3 was 570°C.

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

Example 3

The same apparatus and reaction steps as in Example 1 were employed, except that the light/heavy component cutoff point of the processed crude oil A was 350°C, the cutoff ratio (weight ratio of light fraction to heavy fraction) was 0.529, the weight ratio of the second stream catalyst to the first spent catalyst (second stream catalyst/first spent catalyst) was 0.6, the regenerator temperature was 740°C (i.e., the temperature T0 of the second stream catalyst when it entered step S4 was 740°C), and the riser reactor outlet temperature T3 was 630°C.

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

Example 4

The same apparatus and reaction steps as in Example 1 are used.

The light and heavy fraction cut point of crude oil A processed in this example is 250°C, and the cut ratio (weight ratio of light fraction to heavy fraction) is 0.195.

Except for the conditions listed in Table 3, the same conditions as in Example 1 are adopted.

The results are listed in Table 3.

Example 5

The same apparatus and reaction steps as in Example 1 are used.

The light/heavy fraction cut point of crude oil A processed in this example was 350°C, and the cut ratio (weight ratio of light/heavy fraction) was 0.529. Except for the conditions listed in Table 3, the same conditions as in Example 1 were used.

The results are listed in Table 3.

Example 6

The light/heavy fraction cut point of the processed crude oil A is 320°C, and the cut ratio (weight ratio of light/heavy fraction) is 0.4.

The test was conducted using a modified medium-sized unit with continuous reaction-regeneration operation, the process of which is shown in Figure 2. The 720°C high-temperature regenerated catalyst was introduced from the regenerator into the top of the down-type reactor 1 through the regeneration inclined tube. The light oil, preheated to 45°C, was atomized by water vapor and then entered the down-type reactor 1 through the feed nozzle. It came into contact with the first stream of catalyst to undergo catalytic cracking reaction. The catalyst-to-oil ratio was 40, the reactor outlet temperature was 670°C, and the gas-solid residence time was 0.6s. The material after the first catalytic cracking entered the fluidized bed reactor 2 through the outlet distributor for further catalytic cracking reaction. The reaction temperature was 655°C and the mass space velocity was 4h ^-1. Separately, the light olefin fraction is atomized with steam and then enters the bottom of fluidized bed reactor 2 through feed nozzle 21, where it reacts with the hot catalyst. The resulting material undergoes cyclonic separation to produce a second reaction gas and a second spent catalyst. The second reaction gas is introduced into a subsequent separation system. The separated second spent catalyst is stripped and then introduced into the bottom of the riser reactor (upward reactor 3). Simultaneously, regenerated catalyst (the second stream of catalyst) at a temperature of 720°C is introduced from the regenerator via regenerated catalyst transfer pipe 32 into the bottom of the second upward reactor 3. The weight ratio of the second catalyst to the second spent catalyst (second catalyst/second spent catalyst) is 0.25. After the second spent catalyst and the second catalyst are mixed at the bottom of reactor 3, the mixed catalyst flows upward under the action of pre-lift steam. The heavy oil is atomized with water vapor and then sprayed into the upward reactor 3 through the heavy oil nozzle. It contacts the catalyst and undergoes a catalytic cracking reaction. The oil-to-oil ratio is 20, the reactor outlet temperature T3 is 610°C, and the gas-solid residence time in the reactor is 1.5 seconds. The material after catalytic cracking is introduced into a settler for oil-gas separation. The separation is into third reaction oil gas and third spent catalyst. The reaction oil gas is introduced into the separation system. The second and third reaction oil and gas are separated in a separation system into cracked gas, light gasoline, heavy gasoline, diesel, and oil slurry. A portion of the light gasoline distillate (distillation range: 30-60°C) is returned to fluidized bed reactor 2 as the light olefin distillate. The third spent catalyst enters the stripper, where the hydrocarbon products adsorbed by the spent catalyst are stripped away. It then passes through the spent catalyst inclined tube into the regenerator, where it is exposed to air and regenerated by charring at 720°C. The regenerated catalyst is returned to the reactor through the regeneration inclined tube for recycling. The medium-sized unit uses electric heating to maintain the reaction and regeneration system temperatures. Once the unit is operating stably (with the product composition remaining essentially unchanged), the cracked gas and gasoline compositions obtained from the reaction oil and gas are analyzed to determine the triene and BTX yields in the products.

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

Example 7

The same apparatus and reaction steps as in Example 6 were employed, except that the light/heavy component cutoff point of the processed crude oil A was 250°C, the cutoff ratio (weight ratio of light oil fraction/heavy oil fraction) was 0.195, the weight ratio of the second stream catalyst to the second spent catalyst (second stream catalyst/second spent catalyst) was 0.03, the regenerator temperature was 700°C (i.e., the temperature T0 of the second stream catalyst when it entered step S4 was 700°C), and the riser reactor outlet temperature T3 was 570°C.

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

Example 8

The same apparatus and reaction steps as in Example 6 were employed, except that the light/heavy component cutoff point of the processed crude oil A was 350°C, the cutoff ratio (weight ratio of light oil fraction/heavy oil fraction) was 0.529, the weight ratio of the second stream catalyst to the second spent catalyst (second stream catalyst/second spent catalyst) was 0.6, the regenerator temperature was 740°C (i.e., the temperature T0 of the second stream catalyst when it entered step S4 was 740°C), and the riser reactor outlet temperature T3 was 630°C.

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

Comparative Example 1

The same apparatus, reaction steps, and reaction conditions as in Example 1 are used, except that the light olefin fraction separated from the reaction oil gas is not refluxed to the riser reactor 3.

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

Comparative Example 2

The same apparatus and reaction steps as in Example 1 were used, except that the weight ratio of the second stream of catalyst to the first spent catalyst (second stream of catalyst/first spent catalyst) was 0.1, the regenerator temperature was 740°C (i.e., the temperature T0 of the second stream of catalyst when it entered step S4 was 740°C), and the riser reactor outlet temperature T3 was 610°C.

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

Comparative Example 3

The same apparatus and reaction steps as in Example 1 were employed, except that the weight ratio of the second stream of catalyst to the first spent catalyst (second stream of catalyst/first spent catalyst) was 0.5, the regenerator temperature was 700°C (i.e., the temperature T0 of the second stream of catalyst when it entered step S4 was 700°C), and the riser reactor outlet temperature T3 was 610°C.

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

Comparative Example 4

The same apparatus, reaction steps, and reaction conditions as in Example 1 were used, except that no second stream of catalyst was introduced into the lower portion of the riser reactor 3, and 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, reaction steps, and reaction conditions as in Example 1 were used, except that the first spent catalyst was not introduced into the lower portion of the upward reactor 3, and only the second stream of catalyst was used.

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

Comparative Example 6

The same apparatus, reaction steps, and reaction conditions as in Example 1 were used, except that the light distillate fraction entered the ascending reactor, i.e., the first descending reactor 1 was replaced with an ascending reactor (the parameters of the descending reactor in Table 3 represent the parameters of the ascending reactor in 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 hydrocarbon-containing feedstock provided in this disclosure can significantly increase the yield of light olefins and light aromatics, while simultaneously suppressing the yield of by-products such as dry gas and coke.

The above describes in detail the preferred implementation of this disclosure. However, this disclosure is not limited to the specific details of the above implementation. Within the scope of the technical concept of this disclosure, various simple variations of the technical solution of this disclosure can be made, and these simple variations all fall within the scope of protection of this disclosure.

It should also be noted that the specific technical features described in the above specific embodiments can be combined in any appropriate manner, provided that there is no conflict. To avoid unnecessary repetition, this disclosure will not further explain various possible combinations.

In addition, the various implementations of this disclosure may be combined in any manner, as long as they do not violate the principles of this disclosure and should be considered as part of this disclosure.

1: Downstream Reactor

11: Light oil feed nozzle

12: First stream of catalyst (regenerated catalyst) delivery pipe

21: Light olefin distillate feed nozzle

22: First reaction oil and gas outlet/Second reaction oil and gas outlet

3: Upstream Reactor

31: Continuous catalyst delivery pipe

32: Second catalyst (regeneration catalyst) delivery pipe

33: Heavy oil feed nozzle

4: Sedimenter

41: Third Reactor Oil and Gas Outlet

5: Stripper

53: Third spent catalyst delivery pipe

6: Regenerator

7: Gas-solid separator

Claims (19)

A method for producing light olefins and light aromatics by catalytic cracking of hydrocarbon-containing crude oil, comprising the following steps: S1, cutting the hydrocarbon-containing crude oil into a light fraction and a heavy fraction, wherein the weight ratio of the light fraction to the heavy fraction (light fraction/heavy fraction) is X; S2, introducing the light fraction and a first stream of catalyst into a first down-flow reactor to perform a first catalytic cracking to obtain a material after the first catalytic cracking; and optionally, S2', introducing the material after the first catalytic cracking into a fluidized bed reactor to perform a second catalytic cracking to obtain a second catalytic cracking material; S3, gas-solid separation of the first catalytic cracking material to obtain a first reaction oil gas and a first spent catalyst, or gas-solid separation of the second catalytic cracking material to obtain a second reaction oil gas and a second spent catalyst; S4, introducing the continuous catalyst, the heavy oil and the second catalyst into the second upward reactor to perform a third catalytic cracking, and then performing gas-solid separation to obtain a third reaction oil gas and a third spent catalyst; the continuous catalytic cracking The catalyst is at least a portion of the first spent catalyst or at least a portion of the second spent catalyst; the weight ratio of the second catalyst to the continuous catalyst (second catalyst/continuous catalyst) is R; S5, separating light olefins and light aromatics from any one of the first reaction oil gas, the second reaction oil gas and the third reaction oil gas, or a mixture of the first reaction oil gas and the third reaction oil gas, or a mixture of the second reaction oil gas and the third reaction oil gas, and separating the light olefin fraction, and separating the light aromatic fraction. The olefin fraction is returned to the second upward reactor of step S4 or the fluidized bed reactor of step S2', and 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), where T0 is the temperature (in ° C.) of the second catalyst when it enters step S4, and T3 is the outlet temperature (in ° C.) of the second upward reactor. The method of claim 1, wherein the outlet temperature T3 of the second upward reactor is 530-650°C; and/or the temperature T0 of the second catalyst when entering step S4 is 690-750°C. The method of claim 1 or 2, wherein in step S1, the hydrocarbon-containing feedstock oil is cut into light oil and heavy oil at any temperature between 100°C and 400°C, so that the weight ratio of the light oil to the heavy oil (light oil/heavy oil) is X. The method of claim 1, wherein, in the first down-flow 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 fuel-oil ratio of 15-80; and/or in the fluidized bed reactor, the conditions for the second catalytic cracking include: a reaction temperature of 600-690°C and a mass space velocity of 2-20 h ^-1 in the fluidized bed reactor; and/or in the second up-flow reactor, the conditions for the third catalytic cracking include: a gas-solid residence time of 0.5-8 seconds and a fuel-oil ratio of 8-40. The method of claim 1, wherein, in the first down-flow 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 fuel-oil ratio of 25-65; and/or in the fluidized bed reactor, the conditions for the second catalytic cracking include: a reaction temperature of 640-670°C and a mass space velocity of 4-12 h ^-1 in the fluidized bed reactor; and/or in the second up-flow reactor, the conditions for the third catalytic cracking include: a gas-solid residence time of 1.5-5 seconds and a fuel-oil ratio of 10-30. The method of claim 1, wherein, when step S2' is present, the separated catalyst is stripped in the gas-solid separation of step S3 to obtain a second spent catalyst; and/or in step S4, the continuous catalyst is first mixed with the second catalyst before a subsequent catalytic cracking reaction is carried out; and/or in step S4, the light olefin fraction from step S5 is contacted with the mixture of the second catalyst and the continuous catalyst before the heavy olefin fraction; and/or the method comprises, before step S1, step S0, wherein the hydrocarbon-containing feedstock oil is desalinated and dehydrated, and the dehydrated and desalted hydrocarbon-containing feedstock oil obtained is introduced into step S1 for cutting. The method of claim 1, wherein the method further comprises: in the gas-solid separation of step S4, stripping the separated catalyst to obtain a third spent catalyst; and/or stripping the third spent catalyst and optionally the first spent catalyst or the second spent catalyst that has not entered the second upward reactor at 690- and/or separating any one of the first reaction oil gas, the second reaction oil gas, and the third reaction oil gas, or a mixture of the first reaction oil gas and the third reaction oil gas, or a mixture of the second reaction oil gas and the third reaction oil gas to obtain dry gas, C3 distillate, C4 distillate, light gasoline, heavy gasoline, diesel, and oil slurry, from which light olefins and light aromatics are separated, and a light olefin distillate is separated; and/or Or when step S2' does not exist, in step S5, the light olefin distillate is separated from either the first reaction oil gas, the third reaction oil gas, or a mixture of both, and the light olefin distillate is returned to the second upward reactor in step S4; when step S2' exists, in step S5, the light olefin distillate is separated from either the second reaction oil gas, the third reaction oil gas, or a mixture of both, and the light olefin distillate is returned to the fluidized bed reactor in step S2'. The method of claim 1, wherein the hydrocarbon-containing feedstock oil is one of crude oil, coal liquefaction oil, synthetic oil, oil sands oil, shale oil, tight oil and animal and vegetable oils or a mixture of two or more thereof, or a hydrogenated and reformed oil of a partial distillate or a heavy distillate of each of them. The method of claim 1, wherein the first catalyst and the second catalyst each independently comprise an active component and a carrier, the active component being at least one selected from ultrastable Y-type zeolite containing or not containing rare earth, ZSM-5 series zeolite, high-silicon zeolite having a five-membered ring structure, and beta zeolite, and the carrier being at least one selected from aluminum oxide, silicon oxide, amorphous silicon aluminum, zirconium oxide, titanium oxide, boron oxide, and alkaline earth metal oxide. The method of claim 1, wherein the first catalyst and the second catalyst each independently include a regenerated catalyst, and/or the entire first spent catalyst or the entire second spent catalyst is used as a continuous catalyst. The method of claim 1, wherein the outlet temperature T3 of the second upward reactor is 600-630°C; and/or the temperature T0 of the second catalyst when entering step S4 is 710-725°C; and/or in step S4, the light olefin distillate from step S5 is contacted with the mixture of the second catalyst and the continuous catalyst 0.4-0.8 seconds before the heavy distillate; and/or the third spent catalyst and optionally the first spent catalyst or the second spent catalyst that has not entered the second upward reactor are coked and regenerated at a temperature of 710-725°C to obtain a regenerated catalyst; and/or the first catalyst and the second catalyst are regenerated catalysts. A device for producing light olefins and light aromatics by catalytic cracking of hydrocarbon-containing feedstock oil, the device comprising the following units: a hydrocarbon-containing feedstock oil cutting unit, in which the hydrocarbon-containing feedstock oil is cut into light distillate oil and heavy distillate oil, so that the weight ratio of the light distillate oil to the heavy distillate oil (light distillate oil/heavy distillate oil) is X; a first downward reaction unit, in which the light distillate oil and a first stream of catalyst are introduced from the top of the first downward reaction unit to perform a first catalytic cracking, and a material after the first catalytic cracking is obtained at the bottom of the first downward reaction unit; an optional fluidized bed reaction unit, in which the first catalytic cracking is introduced The first gas-solid separation unit is used to introduce the first catalytic cracking material for gas-solid separation to obtain a first reaction oil gas and a first spent catalyst, or the second catalytic cracking material is introduced for gas-solid separation to obtain a second reaction oil gas and a second spent catalyst; the second ascending reaction unit is used to introduce the continuous catalyst, the second catalyst and the heavy oil from the bottom of the second ascending reaction unit to perform a third catalytic cracking, and the third catalytic cracking material is obtained above the second ascending reaction unit. The continuous catalyst is at least a portion of the first spent catalyst or at least a portion of the second spent catalyst, and 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 to introduce the material after the third catalytic cracking to perform gas-solid separation to obtain a third reaction oil gas and a third spent catalyst; the separation unit is used to introduce any one of the first reaction oil gas, the second reaction oil gas, and the third reaction oil gas, or a mixture of the first reaction oil gas and the third reaction oil gas, or a mixture of the second reaction oil gas and the third reaction oil gas. The reaction mixture is reacted with the catalyst to separate the light olefins and light aromatics, and the light olefin distillate is separated, and the light olefin distillate is returned to the second upward reaction unit or the fluidized bed reaction unit; wherein 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 (unit: ° C.) when the second catalyst enters the second upward reaction unit, and T3 is the outlet temperature (unit: ° C.) of the second upward reaction unit. The apparatus as described in claim 12 further includes a regeneration unit, wherein the third spent catalyst and optionally the first spent catalyst or the second spent catalyst that has not entered the second upward reactor are introduced and coked and regenerated at a temperature of 690-750°C to obtain a regenerated catalyst. The device as described in claim 12 or 13, wherein when the device includes a fluidized bed reaction unit, the first gas-solid separation unit further includes a stripping unit, wherein the catalyst obtained by gas-solid separation is stripped to obtain a second spent catalyst. The device as described in claim 12, wherein the second gas-solid separation unit further includes a stripping unit, wherein the catalyst obtained by gas-solid separation is stripped to obtain a third spent catalyst. The apparatus as described in claim 12, wherein the apparatus further comprises a dehydration and desalination unit, wherein the hydrocarbon-containing raw oil is subjected to desalination and dehydration treatment, and the dehydrated and desalted hydrocarbon-containing raw oil obtained is introduced into a hydrocarbon-containing raw oil cutting unit for cutting. The apparatus as described in claim 12, wherein, in the second upward reaction unit, the position for introducing the continuous catalyst and the second catalyst is upstream of the feed port of the light olefin distillate. The apparatus as described in claim 12, wherein, in the second upward reaction unit, the feed port of the light olefin fraction from the separation unit is upstream of the feed port of the heavy olefin fraction oil. The apparatus as described in claim 12 further includes a regeneration unit, wherein the third spent catalyst and optionally the first spent catalyst or the second spent catalyst that has not entered the second upward reactor are introduced and coked and regenerated at a temperature of 710-725°C to obtain a regenerated catalyst.