阅读说明：本技术 一种生产丙烯和轻芳烃的催化裂解方法 (Catalytic cracking method for producing propylene and light aromatic hydrocarbon ) 是由 朱金泉 高永灿 谢朝钢 崔琰 杨轶男 于 2018-05-30 设计创作，主要内容包括：本发明涉及一种生产丙烯和轻芳烃的催化裂解方法,该方法包括：(1)、将重质烃类原料与第一催化裂解催化剂在第一催化裂解反应器中接触并进行第一催化裂解反应；(2)、将甲醇和第一轻质烃类注入第二催化裂解反应器中与第二催化裂解催化剂接触并进行第二催化裂解反应；(3)、将步骤(2)所得第二反应油气和半待生催化剂引入第三催化裂解反应器中与注入第三催化裂解反应器的第二轻质烃类一起进行第三催化裂解反应；(4)、将所得第一反应油气和第三反应油气进行分离。本发明的方法能够多产丙烯和富含轻芳烃的汽油。(The invention relates to a catalytic cracking method for producing propylene and light aromatic hydrocarbon, which comprises the following steps: (1) contacting the heavy hydrocarbon raw material with a first catalytic cracking catalyst in a first catalytic cracking reactor and carrying out a first catalytic cracking reaction; (2) injecting methanol and first light hydrocarbon into a second catalytic cracking reactor to contact with a second catalytic cracking catalyst and carrying out a second catalytic cracking reaction; (3) introducing the second reaction oil gas obtained in the step (2) and a semi-spent catalyst into a third catalytic cracking reactor to carry out a third catalytic cracking reaction together with second light hydrocarbons injected into the third catalytic cracking reactor; (4) and separating the obtained first reaction oil gas and third reaction oil gas. The method can produce more propylene and gasoline rich in light aromatic hydrocarbon.)

1. A catalytic cracking process for producing propylene and light aromatic hydrocarbons, the process comprising:

(1) Contacting the heavy hydrocarbon raw material with a first catalytic cracking catalyst in a first catalytic cracking reactor and carrying out a first catalytic cracking reaction to obtain first reaction oil gas and a first catalyst to be generated;

(2) injecting methanol and first light hydrocarbon into a second catalytic cracking reactor to contact with a second catalytic cracking catalyst and carrying out a second catalytic cracking reaction to obtain second reaction oil gas and a semi-spent catalyst; wherein the distillation range of the first light hydrocarbon is between 8 and 98 ℃;

(3) Introducing the obtained second reaction oil gas and the semi-spent catalyst into a third catalytic cracking reactor to carry out a third catalytic cracking reaction together with second light hydrocarbons injected into the third catalytic cracking reactor to obtain third reaction oil gas and a second spent catalyst; wherein the distillation range of the second light hydrocarbon is between 60 and 221 ℃;

(4) Separating the obtained first reaction oil gas and the third reaction oil gas to obtain at least propylene, gasoline containing light aromatic hydrocarbon, and a first separation product with a distillation range meeting the requirement of first light hydrocarbon and/or a second separation product with a distillation range meeting the requirement of second light hydrocarbon;

(5) Returning at least part of the first separated product as the first light hydrocarbon to perform the second catalytic cracking reaction, and/or returning at least part of the second separated product as the second light hydrocarbon to perform the third catalytic cracking reaction;

(6) And regenerating the first spent catalyst and the second spent catalyst, wherein the regenerated catalyst is used as the first catalytic cracking catalyst and the second catalytic cracking catalyst.

2. The process of claim 1, wherein the first light hydrocarbon has a boiling range between 9-80 ℃ and the second light hydrocarbon has a boiling range between 80-195 ℃.

3. The process of claim 1, wherein the olefin content of the first light hydrocarbon is from 30 to 90 wt.%.

4. The process of claim 1, wherein the olefin content of the first light hydrocarbon is from 45 to 90 wt%.

5. The method of claim 1, wherein the first and second light hydrocarbons each independently comprise C4 hydrocarbons and/or a gasoline fraction.

6. The process according to claim 1, wherein the heavy hydrocarbon feedstock is at least one selected from the group consisting of petroleum hydrocarbon oils, synthetic oils, coal liquefaction oils, oil sand oils and shale oils.

7. The process of claim 1, wherein the heavy hydrocarbon feedstock is at least one selected from the group consisting of atmospheric gas oil, vacuum gas oil, coker gas oil, deasphalted oil, hydrogenated tail oil, atmospheric residue, vacuum residue, and crude oil.

8. The process of claim 1, wherein the weight ratio of the first light hydrocarbons to heavy hydrocarbon feedstock is (0.01-0.4): 1; the methanol comprises 55-90 wt% of the total weight of the methanol and the first light hydrocarbon;

The weight ratio of the second light hydrocarbon to the heavy hydrocarbon raw material is (0.01-0.4): 1.

9. The process of claim 1, wherein the weight ratio of the first light hydrocarbons to heavy hydrocarbon feedstock is (0.05-0.2): 1; the methanol accounts for 60-80 wt% of the total weight of the methanol and the first light hydrocarbon;

The weight ratio of the second light hydrocarbon to the heavy hydrocarbon raw material is (0.05-0.2): 1.

10. The method of claim 1, wherein methanol and the first light hydrocarbon are mixed and injected together into the second catalytic cracking reactor.

11. The method according to claim 1, wherein the first, second and third catalytic cracking reactors are each independently selected from at least one of a riser reactor, a downer reactor, a fluidized bed reactor, a riser and downer composite reactor, a riser and fluidized bed composite reactor, a downer and fluidized bed composite reactor, and a fluidized bed reactor selected from at least one of a fixed fluidized bed reactor, a bulk fluidized bed reactor, a bubbling bed reactor, a turbulent bed reactor, a fast bed reactor, a transport bed reactor, and a dense phase fluidized bed.

12. The method of claim 1, wherein the first catalytic cracking reactor is a riser reactor, and the conditions of the first catalytic cracking reaction comprise: the reaction temperature is 480-700 ℃, the reaction time is 0.5-10 seconds, and the weight ratio of the catalyst to the oil is (5-40): 1, the weight ratio of water to oil is (0.05-1): 1;

The second catalytic cracking reactor is a riser reactor, and the conditions of the second catalytic cracking reaction comprise: the reaction temperature is 480-700 ℃, the reaction time is 0.5-10 seconds, and the weight ratio of the catalyst to the oil is (5-40): 1, the weight ratio of water to oil is (0.05-1): 1;

The third catalytic cracking reactor is a fluidized bed reactor, and the conditions of the third catalytic cracking reaction comprise that the reaction temperature is 480-650 ℃, the weight hourly space velocity is 0.5-30 h ^-1, the weight ratio of water to oil is (0.05-1) to 1, and the absolute reaction pressure is 0.1-1.5 MPa.

13. The method of claim 12, wherein the conditions of the first catalytic cracking reaction comprise: the reaction temperature is 500-600 ℃, the reaction time is 1-5 seconds, and the weight ratio of the catalyst to the oil is (7-20): 1, the weight ratio of water to oil is (0.1-0.6): 1;

The conditions of the second catalytic cracking reaction include: the reaction temperature is 560 ℃ and 650 ℃, the reaction time is 1-5 seconds, and the weight ratio of the catalyst to the oil is (7-20): 1, the weight ratio of water to oil is (0.1-0.6): 1;

The conditions of the third catalytic cracking reaction comprise reaction temperature of 530 ℃ and 630 ℃, weight hourly space velocity of 1.5-16 h ^-1, weight ratio of water to oil of (0.1-0.6): 1 and absolute reaction pressure of 0.1-0.51 MPa.

14. The process of claim 1, wherein the first catalytic cracking catalyst comprises, on a dry basis and based on the weight of the first catalytic cracking catalyst, 10 to 50 wt% of a zeolite, at least one selected from the group consisting of rare earth-containing or non-containing Y zeolite, HY zeolite, USY zeolite, ZSM-5 series zeolite, high silica zeolite having a pentasil structure, and zeolite Beta, 5 wt% of an inorganic oxide, and 0 to 70 wt% of clay;

The second catalytic cracking catalyst comprises, on a dry basis and based on the weight of the second catalytic cracking catalyst, 10 to 50 wt% of a zeolite, which is at least one selected from the group consisting of rare earth-containing or non-containing Y zeolite, HY zeolite, USY zeolite, ZSM-5 series zeolite, high-silica zeolite having a pentasil structure and Beta zeolite, 5 to 90 wt% of an inorganic oxide and 0 to 70 wt% of clay.

Technical Field

the invention relates to a catalytic cracking method for producing propylene and light aromatic hydrocarbon.

Background

With the development of electric automobiles, the market for motor gasoline and motor diesel has been slowly sought after, so the current petroleum processing technology is seeking to convert petroleum raw materials into high-value chemical products (such as ethylene, propylene, C8 and other light aromatic hydrocarbons). As crude oil becomes heavier, the technical route of preparing gasoline fraction rich in light aromatics and propylene by using a traditional heavy oil catalytic cracking technology as a platform and using cheap heavy oil as a raw material and strengthening deep catalytic cracking reaction of heavy hydrocarbons has high economical efficiency, but the light aromatics and low-carbon olefins produced by a large scale by a traditional catalytic cracking method often need harsher reaction conditions, and if the reaction severity (such as reaction temperature) is reduced, the yield of the light aromatics and the yield of the low-carbon olefins are greatly reduced.

Chinese patent CN 101210190A discloses a method for preparing low-carbon olefin and gasoline by co-feeding heavy petroleum hydrocarbon and methanol, which is carried out on a fluidized catalytic cracking device on a composite molecular sieve catalyst by taking the heavy petroleum hydrocarbon and the methanol as raw materials, wherein the operation temperature of the process is 480-600 ℃, the system pressure is 0.01-0.51 MPa, the weight hourly space velocity is 1.01-20.1 h ^-1, the catalyst-to-oil ratio is 1.0-20.1, the methanol accounts for 1.5-50 w% of the raw material oil, the water injection accounts for 5-50% of the raw material oil, the composite molecular sieve catalyst contains a shape-selective molecular sieve and a large-pore molecular sieve with the weight ratio of 1: 0.1-1.0, and when the heavy petroleum hydrocarbon and the methanol are fed in the same reactor, the effect is that the yield of the low-carbon olefin is increased, the olefin content in the gasoline is reduced, the aromatic content in the gasoline is increased, and the aromatic content reaches 70 wt%.

Chinese patent CN101892067A discloses a method for improving propylene yield and selectivity by promoting catalytic cracking of heavy oil, which is mainly characterized in that during the reaction process, one or more of small amount of small molecular alcohols such as methanol, ethanol, propanol, butanol, etc. is fed together with heavy oil, thereby obviously promoting the conversion rate of heavy oil and improving the yield of liquefied gas and propylene. Compared with other heavy oil catalytic cracking or catalytic cracking yield-increasing or propylene-increasing technologies, the method introduces a small amount of alcohol to improve the yield and selectivity of heavy oil catalytic cracking propylene, and has the advantages of convenient implementation, obvious effect, remarkable economic benefit and the like. The method mainly produces more low-carbon olefins, has low gasoline yield and does not disclose the properties of gasoline products.

The other technology is a process for directly preparing aromatic hydrocarbon from methanol, namely an MTA or MTG process, the adopted catalyst is mainly a ZSM-5-containing molecular sieve catalyst, wherein the content of aromatic hydrocarbon in gasoline is more than 30 percent, and the content of olefin is more than 12 percent, a technology for preparing gasoline from methanol is disclosed in USP3894104, and the content of aromatic hydrocarbon in C ₅ ⁺ gasoline reaches more than 50 percent.

In summary, from the technologies disclosed at present, both the technology for preparing light aromatics and propylene by direct catalytic cracking of heavy hydrocarbon feedstock (FCC technology) and the technology for preparing light aromatics and low-carbon olefins by co-feeding heavy petroleum hydrocarbon and methanol have the technical problems of low selectivity of converting petroleum hydrocarbon into light aromatics and low-carbon olefins and high dry gas and coke yield.

Disclosure of Invention

The invention aims to provide a catalytic cracking method for producing propylene and light aromatic hydrocarbons, which can produce more propylene and gasoline rich in light aromatic hydrocarbons.

In order to achieve the above object, the present invention provides a catalytic cracking process for producing propylene and light aromatic hydrocarbons, the process comprising:

(1) contacting the heavy hydrocarbon raw material with a first catalytic cracking catalyst in a first catalytic cracking reactor and carrying out a first catalytic cracking reaction to obtain first reaction oil gas and a first catalyst to be generated;

(2) Injecting methanol and first light hydrocarbon into a second catalytic cracking reactor to contact with a second catalytic cracking catalyst and carrying out a second catalytic cracking reaction to obtain second reaction oil gas and a semi-spent catalyst; wherein the distillation range of the first light hydrocarbon is between 8 and 98 ℃;

(3) Introducing the obtained second reaction oil gas and the semi-spent catalyst into a third catalytic cracking reactor to carry out a third catalytic cracking reaction together with second light hydrocarbons injected into the third catalytic cracking reactor to obtain third reaction oil gas and a second spent catalyst; wherein the distillation range of the second light hydrocarbon is between 60 and 221 ℃;

(4) Separating the obtained first reaction oil gas and the third reaction oil gas to obtain at least propylene, gasoline containing light aromatic hydrocarbon, and a first separation product with a distillation range meeting the requirement of first light hydrocarbon and/or a second separation product with a distillation range meeting the requirement of second light hydrocarbon;

(5) Returning at least part of the first separated product as the first light hydrocarbon to perform the second catalytic cracking reaction, and/or returning at least part of the second separated product as the second light hydrocarbon to perform the third catalytic cracking reaction;

(6) And regenerating the first spent catalyst and the second spent catalyst, wherein the regenerated catalyst is used as the first catalytic cracking catalyst and the second catalytic cracking catalyst.

Optionally, the distillation range of the first light hydrocarbon is between 9 and 80 ℃, and the distillation range of the second light hydrocarbon is between 80 and 195 ℃.

Optionally, the olefin content of the first light hydrocarbon is from 30 to 90 wt%.

Optionally, the olefin content of the first light hydrocarbon is 45 to 90 wt%.

Optionally, the first and second light hydrocarbons each independently comprise C4 hydrocarbons and/or a gasoline fraction.

Optionally, the heavy hydrocarbon feedstock is at least one selected from the group consisting of petroleum hydrocarbon oil, synthetic oil, coal liquefaction oil, oil sand oil, and shale oil.

Optionally, the heavy hydrocarbon feedstock is at least one selected from the group consisting of atmospheric gas oil, vacuum gas oil, coker gas oil, deasphalted oil, hydrogenated tail oil, atmospheric residue, vacuum residue, and crude oil.

Optionally, the weight ratio of the first light hydrocarbons to the heavy hydrocarbon feedstock is (0.01-0.4): 1; the methanol comprises 55-90 wt% of the total weight of the methanol and the first light hydrocarbon;

The weight ratio of the second light hydrocarbon to the heavy hydrocarbon raw material is (0.01-0.4): 1.

optionally, the weight ratio of the first light hydrocarbons to the heavy hydrocarbon feedstock is (0.05-0.2): 1; the methanol accounts for 60-80 wt% of the total weight of the methanol and the first light hydrocarbon;

The weight ratio of the second light hydrocarbon to the heavy hydrocarbon raw material is (0.05-0.2): 1.

optionally, the methanol and the first light hydrocarbon are mixed and then injected into the second catalytic cracking reactor together.

Optionally, the first catalytic cracking reactor, the second catalytic cracking reactor, and the third catalytic cracking reactor are each independently selected from at least one of a riser reactor, a downer reactor, a fluidized bed reactor, a composite reactor of a riser and a downer, a composite reactor of a riser and a fluidized bed, and a composite reactor of a downer and a fluidized bed, and the fluidized bed reactor is selected from at least one of a fixed fluidized bed reactor, a bulk fluidized bed reactor, a bubbling bed reactor, a turbulent bed reactor, a fast bed reactor, a transport bed reactor, and a dense-phase fluidized bed.

Optionally, the first catalytic cracking reactor is a riser reactor, and the conditions of the first catalytic cracking reaction include: the reaction temperature is 480-700 ℃, the reaction time is 0.5-10 seconds, and the weight ratio of the catalyst to the oil is (5-40): 1, the weight ratio of water to oil is (0.05-1): 1;

The second catalytic cracking reactor is a riser reactor, and the conditions of the second catalytic cracking reaction comprise: the reaction temperature is 480-700 ℃, the reaction time is 0.5-10 seconds, and the weight ratio of the catalyst to the oil is (5-40): 1, the weight ratio of water to oil is (0.05-1): 1;

The third catalytic cracking reactor is a fluidized bed reactor, and the conditions of the third catalytic cracking reaction comprise that the reaction temperature is 480-650 ℃, the weight hourly space velocity is 0.5-30 h ^-1, the weight ratio of water to oil is (0.05-1) to 1, and the absolute reaction pressure is 0.1-1.5 MPa.

Optionally, the conditions of the first catalytic cracking reaction include: the reaction temperature is 500-600 ℃, the reaction time is 1-5 seconds, and the weight ratio of the catalyst to the oil is (7-20): 1, the weight ratio of water to oil is (0.1-0.6): 1;

The conditions of the second catalytic cracking reaction include: the reaction temperature is 560 ℃ and 650 ℃, the reaction time is 1-5 seconds, and the weight ratio of the catalyst to the oil is (7-20): 1, the weight ratio of water to oil is (0.1-0.6): 1;

The conditions of the third catalytic cracking reaction comprise reaction temperature of 530 ℃ and 630 ℃, weight hourly space velocity of 1.5-16 h ^-1, weight ratio of water to oil of (0.1-0.6): 1 and absolute reaction pressure of 0.1-0.51 MPa.

Optionally, the first catalytic cracking catalyst comprises, on a dry basis and based on the weight of the first catalytic cracking catalyst, 10 to 50 wt% of a zeolite, 5 to 90 wt% of an inorganic oxide and 0 to 70 wt% of a clay, the zeolite being at least one selected from the group consisting of rare earth-containing or non-containing Y zeolite, HY zeolite, USY zeolite, ZSM-5 series zeolite, high-silica zeolite having a pentasil structure and Beta zeolite;

The second catalytic cracking catalyst comprises, on a dry basis and based on the weight of the second catalytic cracking catalyst, 10 to 50 wt% of a zeolite, which is at least one selected from the group consisting of rare earth-containing or non-containing Y zeolite, HY zeolite, USY zeolite, ZSM-5 series zeolite, high-silica zeolite having a pentasil structure and Beta zeolite, 5 to 90 wt% of an inorganic oxide and 0 to 70 wt% of clay.

the gasoline obtained by the method has increased content of light aromatic hydrocarbon, increased yield of multi-branched chain isoparaffin and propylene, and reduced yield of dry gas and coke.

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

drawings

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

FIG. 1 is a schematic diagram of one embodiment of a catalytic cracking system for use in the process of the present invention.

Description of the reference numerals

1 first catalytic cracking reactor 2 second catalytic cracking reactor 3 third catalytic cracking reactor

6 settler 7 stripper 9 regenerator

10 separator 11 line 12 line

17 line 20 line 21 line

22 line 23 line 24 line

25 line 26 line 27 line

28 line 29 line 41 line

42 line 43 line 44 line

47 line 51 line 52 line

90 line 91 line 100 external heat exchanger

Detailed Description

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

The invention provides a catalytic cracking method for producing propylene and light aromatic hydrocarbon, which comprises the following steps: (1) contacting the heavy hydrocarbon raw material with a first catalytic cracking catalyst in a first catalytic cracking reactor and carrying out a first catalytic cracking reaction to obtain first reaction oil gas and a first catalyst to be generated; (2) injecting methanol and first light hydrocarbon into a second catalytic cracking reactor to contact with a second catalytic cracking catalyst and carrying out a second catalytic cracking reaction to obtain second reaction oil gas and a semi-spent catalyst; wherein the distillation range of the first light hydrocarbon is between 8 and 98 ℃; (3) introducing the obtained second reaction oil gas and the semi-spent catalyst into a third catalytic cracking reactor to carry out a third catalytic cracking reaction together with second light hydrocarbons injected into the third catalytic cracking reactor to obtain third reaction oil gas and a second spent catalyst; wherein the distillation range of the second light hydrocarbon is between 60 and 221 ℃; (4) separating the obtained first reaction oil gas and the third reaction oil gas to obtain at least propylene, gasoline containing light aromatic hydrocarbon, and a first separation product with a distillation range meeting the requirement of first light hydrocarbon and/or a second separation product with a distillation range meeting the requirement of second light hydrocarbon; (5) returning at least part of the first separated product as the first light hydrocarbon to perform the second catalytic cracking reaction, and/or returning at least part of the second separated product as the second light hydrocarbon to perform the third catalytic cracking reaction; (6) and regenerating the first spent catalyst and the second spent catalyst, wherein the regenerated catalyst is used as the first catalytic cracking catalyst and the second catalytic cracking catalyst.

The inventor finds out through experimental research that the content of light aromatic hydrocarbon in the product gasoline can be obviously increased under a proper reaction condition by adding a certain amount of methanol into light hydrocarbon obtained by catalytic cracking of a heavy hydrocarbon raw material and then carrying out co-refining. Compared with the technical scheme that light hydrocarbons are independently recycled or methanol and heavy hydrocarbon raw materials are fed together in the prior art, the method has the advantages that the reaction effect is better, the yield of light aromatic hydrocarbons and propylene is higher, and the yield of dry gas and coke is reduced. The main reasons are that: (1) the method provided by the invention divides the intermediate product obtained by the cracking reaction of the heavy hydrocarbon raw material into the first light hydrocarbon and the second light hydrocarbon according to the properties, circulates in different reaction stages according to the composition characteristics and the reaction mechanism and co-reacts with methanol in a certain proportion. (2) In the invention, methanol molecules are introduced to react with a first light hydrocarbon and a second light hydrocarbon together, wherein C4-C6 olefin rich in the first light hydrocarbon and methyl micromolecule group released by methanol are subjected to transalkylation reaction, the carbon number of the light hydrocarbon molecules is increased, the number of branched chains is increased, and aromatization reaction is further carried out to convert the light hydrocarbon molecules into aromatic hydrocarbon of C7 and above. Since the first light hydrocarbon is a shorter molecule of C4-C6 (e.g., 2, 3-dimethyl-2-butene, with a main chain of only 4 carbons), 2 or more molecules of methanol are required to react with it to convert it to C7 and above aromatics. (3) The second light hydrocarbon is C7 and above molecules, 1 methanol molecule is needed to generate alkyl transfer reaction and aromatization reaction with the second light hydrocarbon to generate the polymethyl benzene with the C7 or above, and if the second light hydrocarbon has longer molecular chain, the second light hydrocarbon can generate light aromatic hydrocarbon by self aromatization reaction. (4) According to the difference of reaction mechanisms, the first light hydrocarbon needs to be preferentially subjected to catalytic reaction with a large amount of methanol to be effectively converted into the light aromatic hydrocarbon, the required reaction time is longer, the catalytic cracking time of the second light hydrocarbon is shorter, and less methanol needs to participate in the reaction. (5) Therefore, by adopting the method of the invention, the content of light aromatic hydrocarbon in the product gasoline is increased, the yield of the light aromatic hydrocarbon is increased, and the yield of propylene is also increased. Because the methanol is reasonably reacted with the petroleum hydrocarbon according to the optimized reaction path, the reaction efficiency of generating the light aromatic hydrocarbon and the propylene is greatly improved, and the yield of dry gas and the yield of coke are lower.

In the present invention, the distillation range of the first light hydrocarbon is between 8 and 98 ℃, preferably between 9 and 80 ℃, the olefin content of the first light hydrocarbon can be between 30 and 90 wt%, preferably between 45 and 90 wt%, the distillation range of the second light hydrocarbon is between 60 and 221 ℃, preferably between 80 and 195 ℃, the first light hydrocarbon and the second light hydrocarbon can independently comprise C4 hydrocarbon and/or gasoline fraction, and the C4 hydrocarbon fraction and the gasoline fraction can be produced by the method of the present invention and can also be produced by other devices.

According to the present invention, the heavy hydrocarbon feedstock may be at least one selected from the group consisting of petroleum hydrocarbon oils, synthetic oils, coal liquefaction oils, oil sand oils, and shale oils. Preferably, the heavy hydrocarbon feedstock is selected from at least one of atmospheric gas oil, vacuum gas oil, coker gas oil, deasphalted oil, hydrogenated tail oil, atmospheric residue, vacuum residue, and crude oil. The synthetic oil can be distillate oil obtained by Fischer-Tropsch (F-T) synthesis of coal and/or natural gas.

According to the invention, the weight ratio of the first light hydrocarbon to the heavy hydrocarbon feedstock may be (0.01-0.4): 1, preferably (0.05-0.2): 1; the methanol may comprise from 55 to 90 wt%, preferably from 60 to 80 wt%, of the total weight of methanol and first light hydrocarbons; the weight ratio of the second light hydrocarbon to the heavy hydrocarbon feedstock may be (0.01-0.4): 1, preferably (0.05-0.2): 1.

According to the present invention, methanol and the first light hydrocarbon may be mixed and then injected into the second catalytic cracking reactor, or methanol may be injected into the second catalytic cracking reactor upstream or downstream of the injection position of the first light hydrocarbon, preferably, methanol and the first light hydrocarbon may be mixed and then injected into the second catalytic cracking reactor, according to the flow direction of the reaction material.

according to the present invention, the catalytic cracking reactor is well known to those skilled in the art, for example, the first catalytic cracking reactor, the second catalytic cracking reactor and the third catalytic cracking reactor may each be independently selected from at least one of a riser reactor, a downer reactor and a fluidized bed reactor, preferably from at least one of a riser reactor, a downer reactor, a fluidized bed reactor, a riser and downer combined reactor, a riser and fluidized bed combined reactor, a downer and fluidized bed combined reactor, and the third catalytic cracking reactor is preferably a fluidized bed reactor or a combined reactor comprising at least one fluidized bed reactor. The fluidized bed reactor may be at least one selected from the group consisting of a fixed fluidized bed reactor, a bulk fluidized bed reactor, a bubbling bed reactor, a turbulent bed reactor, a fast bed reactor, a transport bed reactor, and a dense phase fluidized bed. The fluidized bed reactor can be a fluidized bed structure with equal diameter or a fluidized bed structure with variable diameter, and the riser reactor and the downer reactor can be a riser reactor and a downer reactor with equal diameter or various riser reactors and downer reactors with variable diameter.

^{-1 -1}In a preferred embodiment, the first catalytic cracking reactor is a riser reactor, the first catalytic cracking reaction conditions may include a reaction temperature (at the outlet of the reactor) of 480-0 ℃ preferably 500-600 ℃, a reaction time of 0.5-10 seconds preferably 1-5 seconds, a catalyst-oil weight ratio of (5-40): 1, preferably (7-20): 1, a water-oil weight ratio (weight ratio of atomized steam to heavy hydrocarbon feedstock) of (0.05-1): 1, preferably (0.1-0.6): 1, the second catalytic cracking reactor is a riser reactor, the second catalytic cracking reaction conditions may include a reaction temperature (at the outlet of the reactor) of 480-700 ℃, preferably 560-650 ℃, further preferably 570-620 ℃, a reaction time of 0.5-10 seconds, preferably 1-5 seconds, a catalyst-oil weight ratio (weight ratio of second catalytic cracking catalyst to first light hydrocarbon) of (at the outlet of the reactor) of 480-35 ℃ preferably 5): 1, a fluidized-10 seconds, preferably 1-5 seconds, a catalyst-oil weight ratio of (weight ratio of 5): 1-5) of (5) to the second catalytic cracking catalyst-35 ℃ preferably 0.05-5), a fluidized reactor, a reaction temperature (at the outlet of 480): 5-35 ℃ preferably 0.5) of 0.5-5, a fluidized bed reactor, a reaction temperature of 5-5, preferably 0.05-10 seconds, a fluidized bed reactor, preferably a fluidized bed reactor, a fluidized bed reactor of (0.5-5-10) of 0.5-5, a fluidized bed reactor, a fluidized bed reactor of 0.5-5, a fluidized bed reactor of a fluidized bed reactor.

According to the present invention, the catalytic cracking catalyst is well known to those skilled in the art, and for example, the first catalytic cracking catalyst comprises, on a dry basis and based on the weight of the first catalytic cracking catalyst, 10 to 50% by weight of a zeolite, which is at least one selected from the group consisting of rare earth-containing or non-containing Y zeolite, HY zeolite, USY zeolite, ZSM-5 series zeolite, high-silica zeolite having a pentasil structure and Beta zeolite, 5 to 90% by weight of an inorganic oxide and 0 to 70% by weight of clay; the second catalytic cracking catalyst comprises, on a dry basis and based on the weight of the second catalytic cracking catalyst, 10 to 50 wt% of a zeolite, which is at least one selected from the group consisting of rare earth-containing or non-containing Y zeolite, HY zeolite, USY zeolite, ZSM-5 series zeolite, high-silica zeolite having a pentasil structure and Beta zeolite, 5 to 90 wt% of an inorganic oxide and 0 to 70 wt% of clay. The first catalytic cracking catalyst and the second catalytic cracking catalyst may be the same or different, preferably the same.

In one embodiment, in the settler, the reaction oil gas and the carbon deposit catalyst to be regenerated are separated, the separated reaction oil gas is introduced into a subsequent separation device, and is further separated to obtain gasoline, and also can be separated to obtain products such as dry gas, liquefied gas, gasoline, diesel oil, heavy oil and the like, and at least part of the first separation product and the second separation product are separated to be used as the first light hydrocarbon and the second light hydrocarbon and are returned to the reactor for recycling.

In one embodiment, the gasoline containing light aromatics is subjected to a solvent extraction device to obtain light aromatics and raffinate oil, wherein the light aromatics are one of target products, the raffinate oil is rich in multi-branched isoparaffin and can be used as a high-octane blending component of the motor gasoline, and the raffinate oil can also be used as first light hydrocarbons or second light hydrocarbons to return for further reaction.

The method according to the invention is further illustrated with reference to fig. 1, but the invention is not limited thereto:

As shown in fig. 1, the first catalytic cracking reactor 1 is a riser reactor, the second catalytic cracking reactor 2 is a riser reactor, the third catalytic cracking reactor 3 is a fluidized bed reactor, and the outlet of the second catalytic cracking reactor 2 is coaxially connected in series with the bottom of the third catalytic cracking reactor 3. The hot regenerated catalyst from the regenerator 9 enters the bottom of the first catalytic cracking reactor 1 through a regenerated catalyst transfer line 11 and is accelerated to flow upward by the action of the pre-lift medium injected through line 51. The preheated heavy hydrocarbon raw material is mixed with the atomized steam from the pipeline 41 through the pipeline 21, and then is injected into the first catalytic cracking reactor 1 to contact with the regenerated catalyst for the first catalytic cracking reaction. The mixture of the first reaction oil gas and the first catalyst to be generated in the first catalytic cracking reactor 1 is quickly separated by a quick separation device at an outlet, and the first catalyst to be generated with carbon deposit is introduced into a stripper 7. The separated reaction oil gas (only comprises the first reaction oil gas from the first catalytic cracking reactor in the starting-up stage, and comprises the reaction oil gas from the first catalytic cracking reactor and the reaction oil gas from the third catalytic cracking reactor in the continuous circulating operation process) is sent to a subsequent separation device 10 for continuous separation through a settler 6 and a pipeline 20 at the top of the settler, and products such as dry gas, liquefied gas, gasoline, diesel oil, heavy oil and the like are obtained after separation (respectively led out through pipelines 25, 26, 27, 28 and 29), and propylene and light aromatic hydrocarbon are further obtained through separation, and meanwhile, a first separation product for recycling can be further obtained through separation and is used as a first light hydrocarbon (led out through a pipeline 23) and a second separation product is used as a second light hydrocarbon (led out through a pipeline 24). The first light hydrocarbon is injected into the second catalytic cracking reactor 2 via line 23 after being mixed with the atomized steam from line 43 to contact the regenerated catalyst lifted by the pre-lift gas from line 12 and injected via line 52 and undergo a second catalytic cracking reaction. Methanol injection can be done in a variety of ways: methanol can be mixed with the atomized steam from the pipeline 43 through the pipeline 23 according to the ratio of (0.05-1): 1, namely, the methanol and the first light hydrocarbon are mixed and then injected into the second catalytic cracking reactor 2; methanol can also be fed via line 22 with the atomized vapor from line 42 in the following (0.05-1): 1, and the mixture is injected into a second catalytic cracking reactor 2, wherein the injection position can be positioned at the upstream and the downstream of the injection point of the first light hydrocarbon. The mixture of the second reaction oil gas and the semi-spent catalyst in the second catalytic cracking reactor 2 is further introduced into a third catalytic cracking reactor 3 through an outlet of the second catalytic cracking reactor 2 for continuous reaction. The second light hydrocarbon is contacted with the mist steam from line 44 via line 24 in the ratio of (0.05-1): 1, then injecting the mixture into the bottom of a third catalytic cracking reactor 3 and an oil mixture of a second catalytic cracking reactor 2 for a third catalytic cracking reaction. Third reaction oil gas and second spent catalyst in the third catalytic cracking reactor 3 are separated and separated through an annular gap between the wall of the third catalytic cracking reactor 3 and a top cap, and the spent catalyst is introduced into a stripper 7. The separated spent catalyst with carbon deposit after reaction enters a stripper 7, stripping steam is injected into the stripper 7 through a pipeline 47 and contacts with the spent catalyst in a countercurrent manner, and reaction oil gas carried by the spent catalyst is stripped as clean as possible. The stripped spent catalyst is sent into a regenerator 9 through a spent agent conveying pipeline 17, air is injected into the regenerator 9 through a pipeline 90, the catalyst is contacted with the heated air in the regenerator and regenerated at the temperature of 600-800 ℃, and the temperature of the regenerator is controlled by an external heat exchanger 100. The regeneration flue gas is led out through a line 91. The regenerated catalyst returns to the first catalytic cracking reactor and the second catalytic cracking reactor for recycling through the regenerant conveying pipelines 11 and 12.

The process provided by the present invention is further illustrated below by way of examples, but the invention is not limited thereto.