CN111484875B

CN111484875B - Catalytic cracking method and reaction system

Info

Publication number: CN111484875B
Application number: CN202010299990.9A
Authority: CN
Inventors: 孙世源; 孟凡东; 闫鸿飞; 张亚西; 武立宪; 张瑞风; 杨鑫
Original assignee: China Petroleum and Chemical Corp; Sinopec Engineering Group Co Ltd
Current assignee: China Petroleum and Chemical Corp; Sinopec Engineering Group Co Ltd
Priority date: 2020-04-16
Filing date: 2020-04-16
Publication date: 2021-11-19
Anticipated expiration: 2040-04-16
Also published as: CN111484875A

Abstract

The embodiment of the invention provides a catalytic cracking method and a reaction system, and relates to the technical field of petroleum refining. The system comprises: a raw material catalytic cracking device, a gasoline catalytic cracking device, a diesel oil catalytic cracking device, a gasoline hydrogenation distillation cutting device and an aromatic hydrocarbon extraction device; the gasoline discharge pipe of the raw material catalytic cracking device is communicated with the gasoline catalytic cracking device, and the diesel discharge pipes of the raw material catalytic cracking device, the gasoline catalytic cracking device and the diesel catalytic cracking device are communicated with the diesel catalytic cracking device; the gasoline discharge pipes of the gasoline catalytic cracking device and the diesel catalytic cracking device are communicated with a gasoline hydrogenation distillation cutting device, the light fraction discharge pipe of the gasoline hydrogenation distillation cutting device is communicated with the gasoline catalytic cracking device, and the heavy fraction discharge pipe of the gasoline hydrogenation distillation cutting device is communicated with an aromatic hydrocarbon extraction device. The method comprises the following steps: the catalytic cracking reaction is carried out by adopting the system. The invention can produce low-carbon olefin and aromatic hydrocarbon without producing catalytic gasoline and catalytic diesel oil, and has obvious economic benefit.

Description

Catalytic cracking method and reaction system

Technical Field

The invention relates to the field of petroleum refining, in particular to a catalytic cracking method and a reaction system.

Background

The demand of Chinese petroleum is increased and slowed down, and even can reach a peak after 2030 years. In 2018, the consumption of Chinese petroleum is about 6.2 hundred million tons, wherein the apparent consumption of finished oil is about 3.21 hundred million tons, and the acceleration is only 0.4 percent. About 80% of the finished oil consumer structure is automotive oil. Although the automobile reserves in China still have a larger growing space, the oil consumption of the automobile is reduced from 6.5 liters/100 kilometers at present to 3.2 liters/100 kilometers in 2030 years along with the improvement of the electric degree of the automobile and the improvement of the efficiency of an engine. This will more significantly inhibit the consumption of the finished oil and eventually lead to saturation of the finished oil market and even the supply process.

At present, a catalytic cracking unit produces 70% of gasoline for vehicles and 30% of diesel oil for vehicles. The increase of gasoline and diesel consumption is slowed down, and the operation rate and economic benefit of the catalytic cracking device are obviously influenced. Under the large background of the transformation from 'fuel type' to 'chemical type' of Chinese oil refining enterprises, the catalytic cracking unit is taken as one of the most important sources of profit of the oil refining enterprises and is responsible for continuously making profits for the oil refining enterprises. This requires that the catalytic cracking process be adapted to new market conditions for technical upgrades.

The technical upgrading of the catalytic cracking process mainly has two directions, one is to produce low-carbon olefin mainly containing propylene, and the other is to produce aromatic hydrocarbon mainly containing BTX.

The domestic developed catalytic cracking propylene production process mainly comprises the following steps: deep Catalytic Cracking (DCC), liquefied gas and gasoline rich catalytic cracking (MGG), liquefied gas and diesel maximum catalytic cracking (MGD), isoparaffin rich catalytic cracking (MIP), flexible multi-effect catalytic cracking (fdfdd), two-riser fcc, and propylene rich catalytic cracking (TMP). The foreign developed catalytic cracking propylene production process mainly comprises the following steps: SCC (selective catalytic cracking) process, petroFCC process, MAXOFIN process, INDAX process, HS-FCC (high-sensitivity fluidic cracking) process.

Among these processes, some continue to use the form of a riser reactor while using more severe reaction conditions, such as DCC process, MGG and ARGG process; some gasoline fractions are recycled to the riser reactor, such as MGD process and SCC process; some conventional riser reactors are divided into two reaction zones to be controlled respectively, such as MIP and MIP-CGP processes; some employ dual riser reactors to simultaneously recycle gasoline and/or carbon four-cut, such as FDFCC process, TMP process, PetroFCC process, MAXOFIN process.

The existing catalytic cracking process for producing more light olefins or more light aromatics still has higher yield of catalytic gasoline or catalytic diesel, and generally adopts harsher reaction conditions, so that the quality of the produced catalytic gasoline or catalytic diesel is worse, and the difficulty of blending vehicle fuel is increased.

In view of the above, the present invention is particularly proposed.

Disclosure of Invention

The present invention aims to provide a catalytic cracking process and reaction system aimed at ameliorating at least one of the problems mentioned in the background.

Embodiments of the invention may be implemented as follows:

in a first aspect, an embodiment of the present invention provides a catalytic cracking reaction system, including a raw material catalytic cracking device, a gasoline catalytic cracking device, a diesel catalytic cracking device, a gasoline hydro-distillation cutting device, and an aromatic hydrocarbon extraction device;

the raw material catalytic cracking device comprises a first cracked gasoline discharge pipe and a first cracked diesel discharge pipe, the first cracked gasoline discharge pipe is communicated with the feeding part of the gasoline catalytic cracking device, and the first cracked diesel discharge pipe is communicated with the feeding part of the diesel catalytic cracking device;

the gasoline catalytic cracking device comprises a second cracked gasoline discharge pipe and a second cracked diesel discharge pipe, the second cracked gasoline discharge pipe is communicated with the feeding part of the gasoline hydro-distillation cutting device, and the second cracked diesel discharge pipe is communicated with the feeding part of the diesel catalytic cracking device;

the diesel oil catalytic cracking device comprises a third cracked gasoline discharge pipe and a third cracked diesel oil discharge pipe, the third cracked gasoline discharge pipe is communicated with the feeding part of the gasoline hydrogenation distillation cutting device, and the third cracked diesel oil discharge pipe is communicated with the feeding part of the diesel oil catalytic cracking device;

the gasoline hydrogenation distillation cutting device is connected with a light fraction discharge pipe and a heavy fraction discharge pipe, the light fraction discharge pipe is communicated with the feeding part of the gasoline catalytic cracking device, and the heavy fraction discharge pipe is communicated with the feeding part of the aromatic hydrocarbon extraction device;

the aromatic extraction device is connected with a raffinate oil discharge pipe and a raffinate oil discharge pipe for discharging low-carbon olefins and aromatic hydrocarbons, and the raffinate oil discharge pipe is communicated with a feeding part of the gasoline catalytic cracking device.

In an alternative embodiment, the number of the raw material catalytic cracking units is two, and the two raw material catalytic cracking units are arranged in parallel.

In an optional embodiment, each raw material catalytic cracking device comprises a first riser and a first fractionating tower, the first riser is connected with a first reactant outflow pipe, the first reactant outflow pipe is communicated with the first fractionating tower, and a first cracked gasoline outflow pipe and a first cracked diesel oil outflow pipe are communicated with the first fractionating tower;

in an optional embodiment, the gasoline catalytic cracking device comprises a second riser and a second fractionating tower, the first cracked gasoline discharge pipe is communicated with the feeding part of the second riser, the second riser is connected with a second reactant discharge pipe, the second reactant discharge pipe is communicated with the second fractionating tower, and the second cracked gasoline discharge pipe and the second cracked diesel discharge pipe are communicated with the second fractionating tower.

In an optional embodiment, the diesel catalytic cracking device comprises a first hydrogenation reactor, a third riser and a third fractionating tower which are sequentially communicated, wherein a first cracked diesel oil discharge pipe, a second cracked diesel oil discharge pipe and a third cracked diesel oil discharge pipe are communicated with the feeding position of the first hydrogenation reactor, and the third fractionating tower is communicated with a third cracked gasoline discharge pipe and a third cracked diesel oil discharge pipe.

In an optional embodiment, the gasoline hydrodistillation cutting device comprises a second hydrogenation reactor and a distillation cutting device, a second cracked gasoline discharge pipe and a third cracked gasoline discharge pipe are communicated with a feeding part of the second hydrogenation reactor, the second hydrogenation reactor is connected with a fourth reactant flow outlet pipe, the fourth reactant flow outlet pipe is communicated with the distillation cutting device, and a light fraction discharge pipe and a heavy fraction discharge pipe are communicated with the distillation cutting device.

In a second aspect, embodiments of the present invention provide a catalytic cracking process comprising:

catalytic cracking of raw materials: carrying out catalytic cracking reaction on the catalytic cracking raw material;

gasoline catalytic cracking: carrying out catalytic cracking reaction on catalytic gasoline generated by catalytic cracking of raw materials;

catalytic cracking of diesel oil: carrying out catalytic cracking reaction on catalytic diesel oil generated by catalytic cracking of raw materials and catalytic diesel oil generated by catalytic cracking of gasoline;

gasoline reprocessing: hydrodesulfurization catalytic gasoline generated by gasoline catalytic cracking and catalytic gasoline generated by diesel catalytic cracking, then carrying out distillation cutting, and refluxing the generated light fraction to carry out catalytic cracking reaction together with the catalytic gasoline generated by raw material catalytic cracking;

aromatic hydrocarbon extraction: aromatic extraction is carried out on heavy fractions generated in the gasoline reprocessing process, and generated raffinate oil flows back to be subjected to catalytic cracking reaction together with catalytic gasoline generated by raw material catalytic cracking.

In an optional embodiment, in the catalytic cracking process of the raw material, the content of the heavy oil raw material H subjected to catalytic cracking is 9.5-15 wt%, and the content of carbon residue is less than or equal to 8 wt%;

in an optional embodiment, the catalytic cracking reaction temperature in the catalytic cracking process of the raw material is 440-650 ℃, preferably 460-550 ℃, and more preferably 480-530 ℃;

in an optional embodiment, the catalyst-to-oil ratio in the catalytic cracking process of the raw material is 3-14, preferably 4-10, and more preferably 5-9;

in an optional embodiment, the reaction pressure in the catalytic cracking process of the raw material is 0.1-0.4 MPa, preferably 0.12-0.38 MPa, and more preferably 0.15-0.35 MPa;

in an optional embodiment, the reaction time in the catalytic cracking process of the raw material is 2-5 s, preferably 2.2-4.5 s, and more preferably 2.5-4 s;

in an alternative embodiment, the atomized steam accounts for 1-4 wt%, preferably 1.2-3.5 wt%, and more preferably 1.5-3 wt% of the feed amount in the catalytic cracking process of the raw material.

In an optional embodiment, in the gasoline catalytic cracking process, the catalytic cracking reaction temperature is 440-650 ℃, preferably 480-600 ℃, and more preferably 500-580 ℃;

in an optional embodiment, the catalyst-to-oil ratio in the gasoline catalytic cracking process is 3-14, preferably 4-13, and more preferably 5-12;

in an optional embodiment, the reaction pressure in the gasoline catalytic cracking process is 0.1-0.4 MPa, preferably 0.12-0.38 MPa, and more preferably 0.15-0.35 MPa;

in an optional embodiment, the reaction time in the gasoline catalytic cracking process is 2-5 s, preferably 2.2-4.5 s, and more preferably 2.5-4 s;

in an alternative embodiment, the atomized steam accounts for 0.5-4 wt%, preferably 0.8-3.5 wt%, and more preferably 1-3 wt% of the feed amount in the gasoline catalytic cracking process.

In an optional embodiment, in the diesel oil catalytic cracking process, firstly, the catalytic diesel oil produced by catalytic cracking of the raw material and the catalytic diesel oil produced by catalytic cracking of gasoline are subjected to hydrofining, so that aromatic hydrocarbons with more than two rings in the diesel oil are converted into saturated hydrocarbons or monocyclic aromatic hydrocarbons, and then catalytic cracking reaction is performed;

in an optional embodiment, the reaction temperature of hydrofining is 320-390 ℃, the hydrogen partial pressure is 5.0-10.0 MPa, and the volume space velocity is 0.5-1.5 h^-1The volume ratio of hydrogen to oil is 300-800: 1;

in an optional embodiment, the metal mass of the catalyst used for hydrofining is 12-30 wt%;

in an optional embodiment, the reaction temperature of the catalytic cracking reaction after the hydrorefining is 440-650 ℃, preferably 480-600 ℃, and more preferably 500-580 ℃;

in an optional embodiment, the catalyst-to-oil ratio of the catalytic cracking reaction after hydrofining is 3-14, preferably 4-13, and more preferably 5-12;

in an optional embodiment, the reaction pressure of the catalytic cracking reaction after the hydrorefining is 0.1 to 0.4MPa, preferably 0.12 to 0.38MPa, and more preferably 0.15 to 0.35 MPa;

in an optional embodiment, the reaction time of the catalytic cracking reaction after the hydrorefining is 2 to 5 seconds, preferably 2.2 to 4.5 seconds, and more preferably 2.5 to 4 seconds;

in an alternative embodiment, the atomized steam for the catalytic cracking reaction after the hydrorefining accounts for 0.5-4 wt%, preferably 0.8-3.5 wt%, and more preferably 1-3 wt% of the feeding amount.

In an optional embodiment, in the gasoline reprocessing process, the reaction temperature of hydrodesulfurization is 400-450 ℃, the hydrogen/oil volume ratio is 1-2, and the volume space velocity is 3.5-4.5 h^-1；

In an alternative embodiment, the catalyst used for hydrodesulfurization is a nickel molybdenum bimetallic catalyst; more preferably, the nickel-molybdenum bimetallic catalyst comprises the following components in percentage by mass: al (Al)₂O₃90-91%, 5.5-6.5% of nickel and 3-4% of molybdenum;

in an alternative embodiment, the distillation cutting temperature is 80-120 ℃;

in an alternative embodiment, the aromatic extraction process employs at least one of N-methylpyrrolidone and sulfolane as an extraction solvent;

in an optional embodiment, the mass ratio of the extraction solvent to the heavy fraction in the aromatic extraction process is 0.5-4: 1;

in an optional embodiment, the temperature of the top of an extraction tower used in the aromatic extraction process is 40-100 ℃, the temperature of the bottom of the extraction tower is 30-90 ℃, and the pressure is 0-2.0 Mpa.

The embodiment of the invention has the beneficial effects that:

the method is characterized in that inferior heavy oil is processed by adopting a catalytic cracking-aromatic extraction combined process, a plurality of groups of catalytic cracking devices are adopted in the catalytic cracking process, the catalytic gasoline and the catalytic diesel oil generated by catalytic cracking are subjected to reflux circulating catalytic cracking, the catalytic gasoline without catalytic cracking capability generated in the process is reprocessed by adopting a hydro-distillation cutting mode, so that light fraction has the capability of catalytic cracking again, heavy fraction can be processed by the aromatic extraction device to obtain raffinate oil capable of catalytic cracking again and extract oil capable of separating and generating low-carbon olefin and aromatic hydrocarbon. The system or the method provided by the invention can produce low-carbon olefin and aromatic hydrocarbon without producing catalytic gasoline and catalytic diesel oil, realizes transformation from an oil refining device to a chemical device, and has remarkable economic and social benefits.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 is a schematic flow diagram of a method provided by the present invention;

fig. 2 is a block diagram of a system provided by the present invention.

Icon: 100-a catalytic cracking reaction system; 101-feedstock catalytic cracking unit; 102-gasoline catalytic cracking unit; 103-diesel catalytic cracking unit; 104-gasoline hydro-distillation cutting device; 1-feeding raw materials into a pipe; 2-a first riser; 3-a first reactant outlet pipe; 4-a first fractionation column; 5-a first gas discharge pipe; 6-a first cracked gasoline outlet pipe; 7-a first cracked diesel discharge pipe; 8-a first slurry discharge pipe; 9-a second riser; 10-a second reactant flow-out pipe; 11-a second fractionation column; 12-a second gas outlet pipe; 13-a second cracked gasoline outlet pipe; 14-a second cracked diesel exhaust pipe; 15-a second slurry discharge pipe; 16-a first hydrogenation reactor; 17-a hydrofinishing product effluent line; 18-a third riser; 19-a third reactant outlet; 20-a third fractionation column; 21-a third gas outlet pipe; 22-a third cracked gasoline outlet pipe; 23-a third cracked diesel discharge pipe; 24-a third slurry discharge pipe; 25-a second hydrogenation reactor; 26-a fourth reactant flow-out pipe; 27-a distillation cutting device; 28-light ends discharge pipe; 29-heavy ends drain; a 30-aromatics extraction unit; 31-raffinate oil discharge pipe; 32-discharge pipe of oil extracted.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, it need not be further defined and explained in subsequent figures.

In the description of the present invention, it should be noted that if the terms "upper", "lower", "inside", "outside", etc. indicate an orientation or a positional relationship based on that shown in the drawings or that the product of the present invention is used as it is, this is only for convenience of description and simplification of the description, and it does not indicate or imply that the device or the element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and thus should not be construed as limiting the present invention.

Furthermore, the appearances of the terms "first," "second," and the like, if any, are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.

It should be noted that the features of the embodiments of the present invention may be combined with each other without conflict.

Referring to fig. 1 and fig. 2, an embodiment of the present invention provides a catalytic cracking reaction system 100, which includes a raw material catalytic cracking device 101, a gasoline catalytic cracking device 102, a diesel catalytic cracking device 103, a gasoline hydro-distillation cutting device 104, and an aromatic hydrocarbon extraction device 30.

The raw material catalytic cracking device 101 comprises a first cracked gasoline discharge pipe 6 and a first cracked diesel discharge pipe 7, wherein the first cracked gasoline discharge pipe 6 is communicated with the feeding position of the gasoline catalytic cracking device 102, and the first cracked diesel discharge pipe 7 is communicated with the feeding position of the diesel catalytic cracking device 103.

Specifically, the raw material catalytic cracking device 101 includes a first riser 2 and a first fractionating tower 4, the first riser 2 is used for carrying out catalytic cracking on the raw material, the first riser 2 is connected with a first reactant outflow pipe 3, the first reactant outflow pipe 3 is communicated with the first fractionating tower 4, and the catalytic cracking product enters the first fractionating tower 4 through the first reactant outflow pipe 3 for fractionation. The first cracked gasoline discharge pipe 6 is communicated with the upper part of the first fractionating tower 4 and used for discharging the catalytic gasoline obtained after fractionation to the gasoline catalytic cracking device 102, and the first cracked diesel discharge pipe 7 is communicated with the lower part of the first fractionating tower and used for discharging the catalytic diesel obtained after fractionation to the diesel catalytic cracking device 103. The upper part of the first fractionating tower 4 is connected with a first gas discharge pipe 5 for discharging light gas obtained after fractionation, and the lower part of the first fractionating tower 4 is connected with a first slurry oil discharge pipe 8 for discharging slurry oil generated after fractionation into a downstream system for treatment.

The gasoline catalytic cracking device 102 comprises a second cracked gasoline discharge pipe 13 and a second cracked diesel discharge pipe 14, the second cracked gasoline discharge pipe 13 is communicated with the feeding position of the gasoline hydro-distillation cutting device 104, and the second cracked diesel discharge pipe 14 is communicated with the feeding position of the diesel catalytic cracking device 103.

Specifically, the gasoline catalytic cracking device 102 includes a second riser 9 and a second fractionator 11, the second riser 9 is used for performing catalytic cracking on the catalytic gasoline discharged from the first cracked gasoline discharge pipe 6, the second riser 9 is connected with a second reactant outflow pipe 10, the second reactant outflow pipe 10 is communicated with the second fractionator 11, and the catalytic cracking product enters the second fractionator 11 through the second reactant outflow pipe 10 for fractionation. A second cracked gasoline discharge pipe 13 is communicated with the upper part of the second fractionating tower 11 for discharging the catalytic gasoline obtained after fractionation to a gasoline hydro-distillation cutting device 104, and a second cracked diesel discharge pipe 14 is communicated with the lower part of the second fractionating tower 11 for discharging the catalytic diesel obtained after fractionation to a diesel catalytic cracking device 103. The upper part of the second fractionating tower 11 is connected with a second gas discharge pipe 12 for discharging the light gas obtained after fractionation, and the lower part of the second fractionating tower 11 is connected with a second slurry oil discharge pipe 15 for discharging the slurry oil generated after fractionation into a downstream system for treatment.

The diesel oil catalytic cracking device 103 comprises a third cracked gasoline discharge pipe 22 and a third cracked diesel oil discharge pipe 23, the third cracked gasoline discharge pipe 22 is communicated with the feeding position of the gasoline hydro-distillation cutting device 104, and the third cracked diesel oil discharge pipe 23 is communicated with the feeding position of the diesel oil catalytic cracking device 103.

Specifically, the diesel catalytic cracking unit 103 includes a first hydrogenation reactor 16, a third riser 18, and a third fractionation tower 20, which are connected in series. The first cracked diesel oil discharge pipe 7, the second cracked diesel oil discharge pipe 14 and the third cracked diesel oil discharge pipe 23 are all communicated with the feeding position of the first hydrogenation reactor 16, and the third fractionating tower 20 is communicated with the third cracked gasoline discharge pipe 22 and the third cracked diesel oil discharge pipe 23. The first hydrogenation reactor 16 is used for hydrofining the catalytic diesel discharged from the first cracked diesel discharge pipe 7, the second cracked diesel discharge pipe 14 and the third cracked diesel discharge pipe 23, the hydrofined catalytic diesel is introduced into the third riser 18 through a hydrofined product outlet pipe 17 connected with the third riser 18 for catalytic cracking after hydrofining, the product after catalytic cracking is introduced into the third fractionating tower 20 through a third reaction product outlet pipe 19 for fractionating, the light gas obtained by fractionating is discharged from the third gas discharge pipe 21, the produced catalytic gasoline is discharged from the third cracked gasoline discharge pipe 22, and the produced catalytic diesel is refluxed to the first hydrogenation reactor 16 from the third cracked diesel discharge pipe 23 for hydrofining again and then catalytic cracking again; the produced slurry oil is discharged from a third slurry oil discharge pipe 24 connected to the bottom of the third fractionation tower 20 to a downstream system for treatment.

The gasoline hydrogenation distillation cutting device 104 is connected with a light fraction discharge pipe 28 and a heavy fraction discharge pipe 29, the light fraction discharge pipe 28 is communicated with the feeding position of the gasoline catalytic cracking device 102, and the heavy fraction discharge pipe 29 is communicated with the feeding position of the aromatic hydrocarbon extraction device 30.

Specifically, the gasoline hydrogenation distillation cutting device 104 includes a second hydrogenation reactor 25 and a distillation cutting device 27, the second cracked gasoline discharge pipe 13 and the third cracked gasoline discharge pipe 22 are communicated with the feeding position of the second hydrogenation reactor 25, the second hydrogenation reactor 25 is connected with a fourth reactant outflow pipe 26, the fourth reactant outflow pipe 26 is communicated with the distillation cutting device 27, and the light fraction discharge pipe 28 and the heavy fraction discharge pipe 29 are communicated with the distillation cutting device 27. The light ends discharge pipe 28 returns the light ends to the second riser 9 for catalytic cracking again. The heavy fraction enters an aromatic extraction device 30 from a heavy fraction discharge pipe 29 to react to produce aromatic hydrocarbon.

The aromatic hydrocarbon extraction device 30 is connected with a raffinate discharge pipe 31 and a raffinate discharge pipe 32 for discharging low-carbon olefins and aromatic hydrocarbons, the raffinate discharge pipe 31 is communicated with the feeding part of the gasoline catalytic cracking device 102, specifically, the second riser 9, and raffinate oil flows back to the second riser 9 through the raffinate discharge pipe 31 to perform catalytic cracking reaction again; and the extract oil is discharged into a downstream aromatic hydrocarbon separation system through an extract oil discharge pipe 32 to be separated to obtain the low-carbon aromatic hydrocarbon.

Preferably, the number of the raw material catalytic cracking unit 101 is two, and the two raw material catalytic cracking units 101 are arranged in parallel. The catalytic cracking efficiency can be improved by arranging two groups of raw material catalytic cracking devices 101 which are connected in parallel. In addition, the arrangement is equivalent to that two sets of catalytic cracking systems are adopted in the device, and 2 sets of catalytic cracking devices adopt the operation modes of double riser reactors, double settlers, double fractionating towers and single regenerators, so that the production efficiency is improved.

Referring to fig. 1 and 2, a catalytic cracking method according to an embodiment of the present invention includes:

s1, catalytic cracking of raw materials: and carrying out catalytic cracking reaction on the catalytic cracking raw material.

The catalytic cracking raw material is input into a first riser 2 from a raw material inlet pipe 1 to carry out catalytic cracking reaction.

In order to ensure that high-quality low-carbon aromatic hydrocarbon can be separated from raffinate oil obtained by final production and the whole system can operate efficiently and stably.

In this step, the catalytic cracking reaction is carried out by selecting a conventional catalyst. The catalyst may be DFC-1, and other catalytic cracking catalysts may also be used.

Preferably, the H content of the heavy oil raw material subjected to catalytic cracking is 9.5-15 wt%, and the carbon residue content is less than or equal to 8 wt%.

Preferably, the catalytic cracking reaction temperature in the catalytic cracking process of the raw material is 440-650 ℃, preferably 460-550 ℃, and more preferably 480-530 ℃.

Preferably, the catalyst-to-oil ratio in the catalytic cracking process of the raw material is 3-14, preferably 4-10, and more preferably 5-9.

Preferably, the reaction pressure in the catalytic cracking process of the raw material is 0.1-0.4 MPa, preferably 0.12-0.38 MPa, and more preferably 0.15-0.35 MPa.

Preferably, the reaction time in the catalytic cracking process of the raw material is 2-5 s, preferably 2.2-4.5 s, and more preferably 2.5-4 s.

Preferably, the atomized steam accounts for 1-4 wt%, preferably 1.2-3.5 wt%, and more preferably 1.5-3 wt% of the feed amount in the catalytic cracking process of the raw material.

S2, gasoline catalytic cracking: carrying out catalytic cracking reaction on the catalytic gasoline generated by the catalytic cracking of the raw material.

And S1, after the catalytic cracking reaction, fractionating the discharged catalytic gasoline by the first fractionating tower 4, and discharging the catalytic gasoline into the second riser 9 through the first cracked gasoline discharge pipe 6 to perform the catalytic cracking reaction.

In order to ensure that the gasoline catalytic cracking process can be stably and efficiently carried out and obtain high-quality products.

Preferably, the catalytic cracking reaction temperature is 440-650 ℃, preferably 480-600 ℃, and more preferably 500-580 ℃;

preferably, the catalyst-to-oil ratio in the gasoline catalytic cracking process is 3-14, preferably 4-13, and more preferably 5-12;

preferably, the reaction pressure in the gasoline catalytic cracking process is 0.1-0.4 MPa, preferably 0.12-0.38 MPa, and more preferably 0.15-0.35 MPa;

preferably, the reaction time in the gasoline catalytic cracking process is 2-5 s, preferably 2.2-4.5 s, and more preferably 2.5-4 s;

preferably, the atomized steam accounts for 0.5-4 wt%, preferably 0.8-3.5 wt%, and more preferably 1-3 wt% of the feed amount in the gasoline catalytic cracking process.

S3, diesel oil catalytic cracking: the catalytic diesel oil produced by catalytic cracking of the raw material and the catalytic diesel oil produced by catalytic cracking of gasoline are subjected to catalytic cracking reaction.

And step S1, after the catalytic cracking reaction, fractionating the discharged catalytic diesel oil by a first fractionating tower 4, and discharging the catalytic diesel oil into a first hydrogenation reactor 16 through a first cracked diesel oil discharge pipe 7 for hydrorefining. And S2, discharging the catalytic diesel oil fractionated by the second fractionating tower 11 into the first hydrogenation reactor 16 through the second cracked diesel oil discharge pipe 14 for hydrorefining after the catalytic cracking reaction. The aromatics with more than two rings in the diesel oil are converted into saturated hydrocarbon or monocyclic aromatics in the first hydrogenation reactor 16, and then discharged into a third riser 18 from a hydrofining product outlet pipe 17 to perform catalytic cracking reaction.

In order to ensure that the catalytic cracking process of the diesel oil can be stably and efficiently carried out and obtain a high-quality product.

Preferably, the reaction temperature of hydrofining is 320-390 ℃, the hydrogen partial pressure is 5.0-10.0 MPa, and the volume space velocity is 0.5-1.5 h^-1The volume ratio of hydrogen to oil is 300-800: 1;

preferably, the active metal in the catalyst used for hydrofinishing comprises one or more of nickel, cobalt, molybdenum or tungsten. Wherein the mass of the active metal is 12-30%. The hydrofining catalyst can be RS-1000, and other hydrofining catalysts can also be adopted.

Preferably, the reaction temperature of the catalytic cracking reaction after hydrofining is 440-650 ℃, preferably 480-600 ℃, and more preferably 500-580 ℃;

preferably, the catalyst-to-oil ratio of the catalytic cracking reaction after hydrofining is 3-14, preferably 4-13, and more preferably 5-12;

preferably, the reaction pressure of the catalytic cracking reaction after hydrofining is 0.1-0.4 MPa, preferably 0.12-0.38 MPa, and more preferably 0.15-0.35 MPa;

preferably, the reaction time of the catalytic cracking reaction after the hydrorefining is 2-5 s, preferably 2.2-4.5 s, and more preferably 2.5-4 s;

preferably, the atomized water vapor for the catalytic cracking reaction after the hydrorefining accounts for 0.5-4 wt%, preferably 0.8-3.5 wt%, and more preferably 1-3 wt% of the feeding amount.

S4, gasoline reprocessing: the catalytic gasoline generated by gasoline catalytic cracking and the catalytic gasoline generated by diesel catalytic cracking are subjected to distillation cutting after hydrodesulfurization, and the generated light fraction reflows to perform catalytic cracking reaction together with the catalytic gasoline generated by raw material catalytic cracking.

Specifically, the catalytic gasoline generated in the step S2 and the catalytic gasoline generated in the step S3 are discharged into the second hydrogenation reactor 25, hydrodesulfurization is performed in the second hydrogenation reactor 25, the hydrodesulfurization is performed, the catalytic gasoline enters the distillation cutting device 27, the light fraction generated after the catalytic gasoline generated in the steps S2 and S3 is subjected to hydrodesulfurization and then subjected to distillation cutting has the capability of catalytic cracking again, and the light fraction is refluxed to the second riser 9 through the light fraction discharge pipe 28 to perform catalytic cracking reaction together with the catalytic gasoline generated in the step S1.

In order to ensure that the reprocessing process of the diesel and the gasoline can be stably and efficiently carried out and obtain high-quality products.

The reaction temperature of the hydrodesulfurization is 400-450 ℃, the reaction pressure is 2.0-4.0 MPa, the volume ratio of hydrogen to oil is 1-2, and the volume space velocity is 3.5-4.5 h^-1；

Preferably, the catalyst used for hydrodesulfurization is a nickel-molybdenum bimetallic catalyst; more preferably, the nickel-molybdenum bimetallic catalyst comprises the following components in percentage by mass: al (Al)₂O₃90-91%, 5.5-6.5% of nickel and 3-4% of molybdenum;

preferably, the distillation cutting temperature is 80-120 ℃;

s5, aromatic extraction: aromatic extraction is carried out on heavy fractions generated in the gasoline reprocessing process, and generated raffinate oil flows back to be subjected to catalytic cracking reaction together with catalytic gasoline generated by raw material catalytic cracking.

The heavy fraction produced in the step S4 is discharged to the aromatics extraction device 30 through the heavy fraction discharge pipe 29 to be subjected to aromatics extraction. Raffinate oil generated in the aromatic hydrocarbon extraction process flows back to the second riser 9 together with the catalytic gasoline generated in the step S1 through the raffinate oil discharge pipe 31 to perform catalytic cracking reaction; extract oil generated in the aromatic extraction process is discharged into a downstream aromatic separation system through an extract oil discharge pipe 32 to be separated to obtain low-carbon olefin or light aromatic.

In order to ensure that the aromatic extraction process can be stably and efficiently carried out and obtain a high-quality product.

Preferably, at least one of N-methyl pyrrolidone and sulfolane is used as an extraction solvent in the aromatic extraction process;

preferably, the mass ratio of the extraction solvent to the heavy fraction in the aromatic extraction process is 0.5-4: 1;

preferably, the temperature of the top of an extraction tower used in the aromatic extraction process is 40-100 ℃, the temperature of the bottom of the extraction tower is 30-90 ℃, and the pressure is 0-2.0 Mpa.

In several examples and comparative examples provided by the present invention, the properties of the heavy oil feedstock employed are as follows:

TABLE 1 heavy oil feedstock Properties

Example 1

In this embodiment, the catalytic cracking reaction system 100 provided by the present invention is used to implement a catalytic cracking method provided by the present invention. The parameters in the operation process are as follows:

a heavy oil feedstock having an H content of about 12 wt% and a carbon residue content of less than or equal to 8 wt% is used.

In the step S1, the catalytic cracking reaction temperature is 510 ℃, the catalyst-to-oil ratio is 6.5, the catalytic cracking reaction pressure is 0.15MPa, the catalytic cracking reaction time is 3.1S, and the atomized water vapor accounts for 2 wt% of the feeding amount in the catalytic cracking process. The catalyst is DFC-1.

In the step S2, the catalytic cracking reaction temperature is 530 ℃, the catalyst-to-oil ratio is 7.5, the catalytic cracking reaction pressure is 0.15MPa, the catalytic cracking reaction time is 3.1S, and the atomized water vapor accounts for 2 wt% of the feeding amount in the catalytic cracking process. The catalyst is DFC-1.

In the step S3, the reaction temperature of hydrofining is 400 ℃, the hydrogen partial pressure is 6.0MPa, and the volume space velocity is 8h^-1The volume ratio of hydrogen to oil is 800:1, the catalyst used for hydrofining is RS-1000, and the active metal is nickel, and the mass ratio of the active metal is 25 wt%.

The catalytic cracking reaction temperature is 550 ℃, the catalyst-oil ratio is 9.5, the catalytic cracking reaction pressure is 0.15MPa, the catalytic cracking reaction time is 3.1s, and the atomized water vapor accounts for 2 wt% of the feeding amount in the catalytic cracking process. The catalyst is DFC-1.

In the step S4, the reaction temperature of hydrodesulfurization is 420 ℃, the reaction pressure is 3.0MPa, the hydrogen/oil volume ratio is 5, and the volume space velocity is 3h^-1(ii) a The catalyst used for hydrodesulfurization is a nickel-molybdenum bimetallic catalyst which comprises the following components in percentage by mass: al (Al)₂O₃90.5 percent of nickel, 6 percent of nickel and 3.5 percent of molybdenum; the distillation cut temperature was 100 ℃.

In step S5, sulfolane is used as the extraction solvent. The mass ratio of the extraction solvent to the heavy fraction was 4: 1. The temperature of the top of the extraction tower used in the aromatic extraction process is 80 ℃, the temperature of the bottom of the extraction tower is 60 ℃, and the pressure is 1 Mpa.

Example 2

In the step S1, the catalytic cracking reaction temperature is 500 ℃, the catalyst-to-oil ratio is 7, the catalytic cracking reaction pressure is 0.25MPa, the catalytic cracking reaction time is 3S, and the atomized water vapor accounts for 2 wt% of the feeding amount in the catalytic cracking process. The catalyst is DFC-1.

In the step S2, the catalytic cracking reaction temperature is 540 ℃, the catalyst-to-oil ratio is 8, the catalytic cracking reaction pressure is 0.25MPa, the catalytic cracking reaction time is 3S, and the atomized water vapor accounts for 2 wt% of the feeding amount in the catalytic cracking process. The catalyst is DFC-1.

In the step S3, the reaction temperature of hydrofining is 350 ℃, the hydrogen partial pressure is 8.0MPa, and the volume space velocity is 1.0h^-1The volume ratio of hydrogen to oil is 500:1, the catalyst used for hydrofining is RS-1000, and the active metal is nickel, and the mass ratio of the active metal is 25 wt%.

The catalytic cracking reaction temperature is 540 ℃, the catalyst-oil ratio is 8, the catalytic cracking reaction pressure is 0.25MPa, the catalytic cracking reaction time is 3s, and the atomized steam accounts for 2 wt% of the feeding amount in the catalytic cracking process. The catalyst is DFC-1.

In the step S4, the reaction temperature of hydrodesulfurization is 400 ℃, the reaction pressure is 2.0MPa, the volume ratio of hydrogen to oil is 2, and the volume space velocity is 3.5h^-1(ii) a The catalyst used for hydrodesulfurization is a nickel-molybdenum bimetallic catalyst which comprises the following components in percentage by mass: al (Al)₂O₃90.5 percent of nickel, 6 percent of nickel and 3.5 percent of molybdenum; the distillation cut temperature was 100 ℃.

In step S5, N-methylpyrrolidone is used as an extraction solvent. The mass ratio of the extraction solvent to the heavy fraction was 2: 1. The temperature of the top of the extraction tower used in the aromatic extraction process is 70 ℃, the temperature of the bottom of the extraction tower is 60 ℃, and the pressure is 0.5 Mpa.

Example 3

a heavy oil feedstock having an H content of about 9.5 wt% and a carbon residue content of less than or equal to 8 wt% is used.

In the step S1, the catalytic cracking reaction temperature is 480 ℃, the catalyst-to-oil ratio is 5, the catalytic cracking reaction pressure is 0.15MPa, the catalytic cracking reaction time is 3S, and the atomized water vapor accounts for 2 wt% of the feeding amount in the catalytic cracking process. The catalyst is DFC-1.

In the step S2, the catalytic cracking reaction temperature is 500 ℃, the catalyst-to-oil ratio is 5, the catalytic cracking reaction pressure is 0.15MPa, the catalytic cracking reaction time is 2.5S, and the atomized water vapor accounts for 1 wt% of the feeding amount in the catalytic cracking process. The catalyst is DFC-1.

In the step S3, the reaction temperature of hydrofining is 320 ℃, the hydrogen partial pressure is 5.0MPa, and the volume space velocity is 0.5h^-1The volume ratio of hydrogen to oil is 300:1, the catalyst used for hydrofining is RS-1000, and the active metal in the catalyst is nickel, cobalt and molybdenum, and the active metal accounts for 12 wt%.

The catalytic cracking reaction temperature is 500 ℃, the catalyst-oil ratio is 5, the catalytic cracking reaction pressure is 0.15MPa, the catalytic cracking reaction time is 2.5s, and the atomized water vapor accounts for 1 wt% of the feeding amount in the catalytic cracking process. The catalyst is DFC-1.

In the step S4, the reaction temperature of hydrodesulfurization is 450 ℃, the reaction pressure is 4.0MPa, the volume ratio of hydrogen to oil is 1, and the volume space velocity is 3.5h^-1(ii) a The catalyst used for hydrodesulfurization is a nickel-molybdenum bimetallic catalyst which comprises the following components in percentage by mass: al (Al)₂O₃90 percent, 6.5 percent of nickel and 3.5 percent of molybdenum; the distillation cut temperature was 80 ℃.

In step S5, N-methylpyrrolidone is used as an extraction solvent. The mass ratio of the extraction solvent to the heavy fraction was 0.5: 1. The temperature of the top of the extraction tower used in the aromatic extraction process is 40 ℃, the temperature of the bottom of the extraction tower is 30 ℃, and the pressure is 0 Mpa.

Example 4

a heavy oil feedstock having an H content of about 15 wt% and a carbon residue content of less than or equal to 8 wt% is used.

In the step S1, the catalytic cracking reaction temperature is 530 ℃, the catalyst-to-oil ratio is 9, the catalytic cracking reaction pressure is 0.35MPa, the catalytic cracking reaction time is 4S, and the atomized water vapor accounts for 3 wt% of the feeding amount in the catalytic cracking process. The catalyst is DFC-1.

In the step S2, the catalytic cracking reaction temperature is 580 ℃, the catalyst-to-oil ratio is 12, the catalytic cracking reaction pressure is 0.35MPa, the catalytic cracking reaction time is 4S, and the atomized water vapor accounts for 3 wt% of the feeding amount in the catalytic cracking process. The catalyst is DFC-1.

In the step S3, the reaction temperature of hydrofining is 390 ℃, the hydrogen partial pressure is 10MPa, and the volume space velocity is 1.5h^-1The volume ratio of hydrogen to oil is 800:1, the catalyst used for hydrofining is RS-1000, wherein the active metals are nickel, cobalt, molybdenum and tungsten, and the active metals account for 30 wt%. The hydrofining catalyst can be RS-1000, and other hydrofining catalysts can also be adopted.

The catalytic cracking reaction temperature is 580 ℃, the catalyst-oil ratio is 12, the catalytic cracking reaction pressure is 0.35MPa, the catalytic cracking reaction time is 4s, and the atomized steam accounts for 3 wt% of the feeding amount in the catalytic cracking process. The catalyst is DFC-1.

In the step S4, the reaction temperature of hydrodesulfurization is 420 ℃, the reaction pressure is 3.0MPa, the hydrogen/oil volume ratio is 1.5, and the volume space velocity is 4.5h^-1(ii) a The catalyst used for hydrodesulfurization is a nickel-molybdenum bimetallic catalyst which comprises the following components in percentage by mass: al (Al)₂O₃91%, 5.5% of nickel and 3.5% of molybdenum; the distillation cut temperature was 120 ℃.

In step S5, N-methylpyrrolidone is used as an extraction solvent. The mass ratio of the extraction solvent to the heavy fraction was 4: 1. The temperature of the top of the extraction tower used in the aromatic extraction process is 100 ℃, the temperature of the bottom of the extraction tower is 90 ℃, and the pressure is 2 Mpa.

Example 5

a heavy oil feedstock having an H content of about 10 wt% and a carbon residue content of less than or equal to 8 wt% is used.

In the step S1, the catalytic cracking reaction temperature is 460 ℃, the catalyst-to-oil ratio is 4, the catalytic cracking reaction pressure is 0.38MPa, the catalytic cracking reaction time is 2.2S, and the atomized water vapor accounts for 1.2 wt% of the feeding amount in the catalytic cracking process. The catalyst is DFC-1.

In the step S2, the catalytic cracking reaction temperature is 480 ℃, the catalyst-to-oil ratio is 13, the catalytic cracking reaction pressure is 0.38MPa, the catalytic cracking reaction time is 4.5S, and the atomized water vapor accounts for 3.5 wt% of the feeding amount in the catalytic cracking process. The catalyst is DFC-1.

In the step S3, the reaction temperature of hydrofining is 380 ℃, the hydrogen partial pressure is 6.0MPa, and the volume space velocity is 1.2h^-1The volume ratio of hydrogen to oil is 600:1, the catalyst used for hydrofining is RS-1000, the active metal is tungsten, and the weight ratio of the tungsten is 25 wt%.

The catalytic cracking reaction temperature is 600 ℃, the catalyst-oil ratio is 13, the catalytic cracking reaction pressure is 0.38MPa, the catalytic cracking reaction time is 4.5s, and the atomized water vapor accounts for 3.5 wt% of the feeding amount in the catalytic cracking process. The catalyst is DFC-1.

In the step S4, the reaction temperature of hydrodesulfurization is 420 ℃, the reaction pressure is 3.0MPa, the hydrogen/oil volume ratio is 1.5, and the volume space velocity is 4.5h^-1(ii) a The catalyst used for hydrodesulfurization is a nickel-molybdenum bimetallic catalyst which comprises the following components in percentage by mass: al (Al)₂O₃91%, 6% of nickel and 3% of molybdenum; the distillation cut temperature was 110 ℃.

In step S5, sulfolane is used as the extraction solvent. The mass ratio of the extraction solvent to the heavy fraction was 3: 1. The temperature of the top of the extraction tower used in the aromatic extraction process is 90 ℃, the temperature of the bottom of the extraction tower is 80 ℃, and the pressure is 1.5 Mpa.

Example 6

In the step S1, the catalytic cracking reaction temperature is 550 ℃, the catalyst-to-oil ratio is 10, the catalytic cracking reaction pressure is 0.12MPa, the catalytic cracking reaction time is 4.5S, and the atomized water vapor accounts for 3.5 wt% of the feeding amount in the catalytic cracking process. The catalyst is DFC-1.

In the step S2, the catalytic cracking reaction temperature is 600 ℃, the catalyst-to-oil ratio is 4, the catalytic cracking reaction pressure is 0.12MPa, the catalytic cracking reaction time is 2.2S, and the atomized water vapor accounts for 0.8 wt% of the feeding amount in the catalytic cracking process. The catalyst is DFC-1.

In the step S3, the reaction temperature of hydrofining is 380 ℃, the hydrogen partial pressure is 6MPa, and the volume space velocity is 1.2h^-1The volume ratio of hydrogen to oil is 600:1, the catalyst used for hydrofining is RS-1000, and the active metal is molybdenum, and the weight ratio of the molybdenum is 25 wt%.

The catalytic cracking reaction temperature is 480 ℃, the catalyst-oil ratio is 4, the catalytic cracking reaction pressure is 0.12MPa, the catalytic cracking reaction time is 2.2s, and the atomized water vapor accounts for 0.8 wt% of the feeding amount in the catalytic cracking process. The catalyst is DFC-1.

In the step S4, the reaction temperature of hydrodesulfurization is 420 ℃, the reaction pressure is 2.0MPa, the hydrogen/oil volume ratio is 1.5, and the volume space velocity is 4.5h^-1(ii) a The catalyst used for hydrodesulfurization is a nickel-molybdenum bimetallic catalyst which comprises the following components in percentage by mass: al (Al)₂O₃90.5 percent of nickel, 5.5 percent of nickel and 4 percent of molybdenum; the distillation cut temperature was 90 ℃.

In step S5, sulfolane is used as the extraction solvent. The mass ratio of the extraction solvent to the heavy fraction was 2: 1. The temperature at the top of the extraction tower used in the aromatic extraction process is 60 ℃, the temperature at the bottom of the extraction tower is 50 ℃, and the pressure is 1.0 Mpa.

Example 7

In the step S1, the catalytic cracking reaction temperature is 440 ℃, the catalyst-to-oil ratio is 14, the catalytic cracking reaction pressure is 0.1MPa, the catalytic cracking reaction time is 5S, and the atomized water vapor accounts for 4 wt% of the feeding amount in the catalytic cracking process. The catalyst is DFC-1.

In the step S2, the catalytic cracking reaction temperature is 650 ℃, the catalyst-to-oil ratio is 3, the catalytic cracking reaction pressure is 0.1MPa, the catalytic cracking reaction time is 2S, and the atomized water vapor accounts for 0.5 wt% of the feeding amount in the catalytic cracking process. The catalyst is DFC-1.

In the step S3, the reaction temperature for hydrorefining was 390 ℃ and the hydrogen content wasThe pressure is 5MPa, and the volume space velocity is 1.2h^-1The volume ratio of hydrogen to oil is 600:1, the catalyst used for hydrofining is RS-1000, the active metal of the catalyst is cobalt, and the ratio of the active metal to the cobalt is 25 wt%.

The catalytic cracking reaction temperature is 440 ℃, the catalyst-oil ratio is 3, the catalytic cracking reaction pressure is 0.1MPa, the catalytic cracking reaction time is 2s, and the atomized steam accounts for 0.5 wt% of the feeding amount in the catalytic cracking process. The catalyst is DFC-1.

In the step S4, the reaction temperature of hydrodesulfurization is 420 ℃, the reaction pressure is 4.0MPa, the hydrogen/oil volume ratio is 1.5, and the volume space velocity is 4.5h^-1(ii) a The catalyst used for hydrodesulfurization is a nickel-molybdenum bimetallic catalyst which comprises the following components in percentage by mass: al (Al)₂O₃90.5 percent of nickel, 5.5 percent of nickel and 4 percent of molybdenum; the distillation cut temperature was 90 ℃.

Example 8

In the step S1, the catalytic cracking reaction temperature is 650 ℃, the catalyst-to-oil ratio is 3, the catalytic cracking reaction pressure is 0.4MPa, the catalytic cracking reaction time is 2S, and the atomized water vapor accounts for 1 wt% of the feeding amount in the catalytic cracking process. The catalyst is DFC-1.

In the step S2, the catalytic cracking reaction temperature is 440 ℃, the catalyst-to-oil ratio is 14, the catalytic cracking reaction pressure is 0.4MPa, the catalytic cracking reaction time is 5S, and the atomized water vapor accounts for 4 wt% of the feeding amount in the catalytic cracking process. The catalyst is DFC-1.

In the step S3, the reaction temperature of hydrofining is 320 ℃, the hydrogen partial pressure is 5MPa, and the volume space velocity is 1.2h^-1The volume ratio of hydrogen to oil is 600:1, the catalyst used for hydrofining is RS-1000, and the catalyst isThe active metals in the alloy are cobalt and molybdenum, and the active metal accounts for 25 wt%.

The catalytic cracking reaction temperature is 650 ℃, the catalyst-oil ratio is 14, the catalytic cracking reaction pressure is 0.4MPa, the catalytic cracking reaction time is 5s, and the atomized steam accounts for 4 wt% of the feeding amount in the catalytic cracking process. The catalyst is DFC-1.

In the step S4, the reaction temperature of hydrodesulfurization is 420 ℃, the reaction pressure is 3.0MPa, the hydrogen/oil volume ratio is 1.5, and the volume space velocity is 4.5h^-1(ii) a The catalyst used for hydrodesulfurization is a nickel-molybdenum bimetallic catalyst which comprises the following components in percentage by mass: al (Al)₂O₃90.5 percent of nickel, 5.5 percent of nickel and 4 percent of molybdenum; the distillation cut temperature was 90 ℃.

Comparative example 1

The comparative example adopts a conventional high-low parallel heavy oil catalytic cracking process.

Examples of the experiments

The same feedstock was catalytically cracked using the methods provided in example 1 and comparative example 1. The raw material properties are shown in Table 1, the main operating conditions are shown in Table 2, and the product distribution is shown in Table 3.

Table 2 comparison of main operating conditions

Table 3 product distribution in the experimental groups

As can be seen from Table 3, compared with the comparative example, the yield of the liquefied gas is improved by about 30 percent, fuel oil such as gasoline and diesel oil is not produced, and light aromatic hydrocarbon below C9 reaches about 32 percent.

In summary, the catalytic cracking reaction system and method provided by the present invention process the inferior heavy oil by a catalytic cracking-aromatic extraction combined process, the catalytic cracking process adopts multiple sets of catalytic cracking devices, the catalytic gasoline and the catalytic diesel oil generated by catalytic cracking are subjected to reflux circulation catalytic cracking, the catalytic gasoline without catalytic cracking capability generated in the process is reprocessed by adopting a hydro-distillation cutting mode, so that the light fraction has the capability of catalytic cracking again, and the heavy fraction can be processed by the aromatic extraction device to obtain raffinate oil capable of catalytic cracking again and extract oil capable of separating and generating low-carbon olefins and aromatic hydrocarbons. The system or the method provided by the invention can produce low-carbon olefin and aromatic hydrocarbon without producing catalytic gasoline and catalytic diesel oil, realizes transformation from an oil refining device to a chemical device, and has remarkable economic and social benefits.

The above description is only for the specific embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.

Claims

1. A catalytic cracking reaction system is characterized by comprising a raw material catalytic cracking device, a gasoline catalytic cracking device, a diesel oil catalytic cracking device, a gasoline hydrogenation distillation cutting device and an aromatic hydrocarbon extraction device;

the gasoline catalytic cracking device comprises a second cracked gasoline discharge pipe and a second cracked diesel discharge pipe, the second cracked gasoline discharge pipe is communicated with the feeding part of the gasoline hydrogenation distillation cutting device, and the second cracked diesel discharge pipe is communicated with the feeding part of the diesel catalytic cracking device;

2. The catalytic cracking reaction system of claim 1, wherein the number of the raw material catalytic cracking unit is two, and the two raw material catalytic cracking units are arranged in parallel.

3. The catalytic cracking reaction system of claim 2, wherein each of the raw material catalytic cracking devices further comprises a first riser and a first fractionating tower, the first riser is connected with a first reactant outflow pipe, the first reactant outflow pipe is communicated with the first fractionating tower, and the first cracked gasoline exhaust pipe and the first cracked diesel oil exhaust pipe are communicated with the first fractionating tower.

4. The catalytic cracking reaction system of claim 3, wherein the gasoline catalytic cracking device further comprises a second riser and a second fractionating tower, the first cracked gasoline outlet pipe is communicated with a feeding position of the second riser, the second riser is connected with a second reactant outlet pipe, the second reactant outlet pipe is communicated with the second fractionating tower, and the second cracked gasoline outlet pipe and the second cracked diesel oil outlet pipe are communicated with the second fractionating tower.

5. The catalytic cracking reaction system of claim 1 or 2, wherein the diesel catalytic cracking apparatus further comprises a first hydrogenation reactor, a third riser and a third fractionating tower, which are sequentially communicated with each other, the first cracked diesel discharge pipe, the second cracked diesel discharge pipe and the third cracked diesel discharge pipe are all communicated with the feeding position of the first hydrogenation reactor, and the third fractionating tower is communicated with the third cracked gasoline discharge pipe and the third cracked diesel discharge pipe.

6. The catalytic cracking reaction system of claim 1 or 2, wherein the gasoline hydrogenation distillation cutting device comprises a second hydrogenation reactor and a distillation cutting device, the second cracked gasoline outlet pipe and the third cracked gasoline outlet pipe are communicated with a feeding position of the second hydrogenation reactor, the second hydrogenation reactor is connected with a fourth reactant outlet pipe, the fourth reactant outlet pipe is communicated with the distillation cutting device, and the light fraction outlet pipe and the heavy fraction outlet pipe are communicated with the distillation cutting device.

7. A catalytic cracking process, characterized in that it comprises:

8. The catalytic cracking method of claim 7, wherein in the catalytic cracking process of the feedstock, the heavy oil feedstock subjected to catalytic cracking has an H content of 9.5-15 wt% and a carbon residue content of 8 wt% or less.

9. The catalytic cracking method of claim 7, wherein the catalytic cracking reaction temperature during the catalytic cracking of the feedstock is 440-650 ℃.

10. The catalytic cracking process of claim 9, wherein the catalytic cracking reaction temperature during the catalytic cracking of the feedstock is 460-550 ℃.

11. The catalytic cracking process of claim 10, wherein the catalytic cracking reaction temperature during the catalytic cracking of the feedstock is 480-530 ℃.

12. The catalytic cracking method of claim 7, wherein the catalyst-to-oil ratio in the catalytic cracking of the feedstock is 3-14.

13. The catalytic cracking method of claim 12, wherein the catalyst-to-oil ratio in the catalytic cracking of the feedstock is 4-10.

14. The catalytic cracking process of claim 13, wherein the catalyst-to-oil ratio in the catalytic cracking of the feedstock is 5 to 9.

15. The catalytic cracking process of claim 7, wherein the reaction pressure in the catalytic cracking process of the raw material is 0.1-0.4 MPa.

16. The catalytic cracking process of claim 15, wherein the reaction pressure during the catalytic cracking of the feedstock is 0.12-0.38 MPa.

17. The catalytic cracking process of claim 16, wherein the reaction pressure during the catalytic cracking of the feedstock is 0.15-0.35 MPa.

18. The catalytic cracking process of claim 7, wherein the reaction time in the catalytic cracking process of the raw material is 2-5 s.

19. The catalytic cracking process of claim 18, wherein the reaction time in the catalytic cracking process of the feedstock is 2.2-4.5 s.

20. The catalytic cracking process of claim 19, wherein the reaction time in the catalytic cracking process of the feedstock is 2.5-4 s.

21. The catalytic cracking process of claim 7, wherein the atomized steam accounts for 1-4 wt% of the feed amount in the catalytic cracking process of the raw material.

22. The catalytic cracking process of claim 21, wherein the atomized steam accounts for 1.2-3.5 wt% of the feed amount in the catalytic cracking process of the raw material.

23. The catalytic cracking process of claim 22, wherein the atomized steam accounts for 1.5-3 wt% of the feed amount in the catalytic cracking process of the raw material.

24. The catalytic cracking method of claim 7, wherein the catalytic cracking reaction temperature is 440-650 ℃ in the gasoline catalytic cracking process.

25. The catalytic cracking process of claim 24, wherein the catalytic cracking reaction temperature is 480-600 ℃ in the gasoline catalytic cracking process.

26. The catalytic cracking process of claim 25, wherein the catalytic cracking reaction temperature is 500-580 ℃ during the gasoline catalytic cracking process.

27. The catalytic cracking method of claim 7, wherein the catalyst-to-oil ratio in the gasoline catalytic cracking process is 3-14.

28. The catalytic cracking process of claim 27, wherein the catalyst-to-oil ratio in the gasoline catalytic cracking process is 4-13.

29. The catalytic cracking process of claim 28, wherein the catalyst-to-oil ratio in the gasoline catalytic cracking process is 5-12.

30. The catalytic cracking process of claim 7, wherein the reaction pressure in the gasoline catalytic cracking process is 0.1-0.4 MPa.

31. The catalytic cracking process of claim 30, wherein the reaction pressure during the gasoline catalytic cracking process is 0.12-0.38 MPa.

32. The catalytic cracking process of claim 31, wherein the reaction pressure during the gasoline catalytic cracking process is 0.15-0.35 MPa.

33. The catalytic cracking process of claim 7, wherein the reaction time in the gasoline catalytic cracking process is 2-5 s.

34. The catalytic cracking process of claim 33, wherein the reaction time in the gasoline catalytic cracking process is 2.2-4.5 s.

35. The catalytic cracking process of claim 34, wherein the reaction time in the gasoline catalytic cracking process is 2.5-4 s.

36. The catalytic cracking process of claim 7, wherein the atomized steam accounts for 0.5-4 wt% of the feed amount in the gasoline catalytic cracking process.

37. The catalytic cracking process of claim 36, wherein the atomized steam accounts for 0.8-3.5 wt% of the feed amount in the gasoline catalytic cracking process.

38. The catalytic cracking process of claim 37, wherein the atomized steam accounts for 1-3 wt% of the feed amount in the gasoline catalytic cracking process.

39. The catalytic cracking method of claim 7, wherein in the catalytic cracking process of diesel oil, the catalytic diesel oil produced by catalytic cracking of raw materials and the catalytic diesel oil produced by catalytic cracking of gasoline are first hydrofined to convert aromatics with more than two rings in the diesel oil into saturated hydrocarbons or monocyclic aromatics, and then catalytic cracking reaction is performed.

40. The catalytic cracking process of claim 39, wherein the hydrofining reaction temperature is 320-390 ℃, the hydrogen partial pressure is 5.0-10.0 MPa, and the volume space velocity is 0.5-1.5 h^-1The volume ratio of hydrogen to oil is 300-800: 1.

41. The catalytic cracking process of claim 39, wherein the metal content of the catalyst used for the hydrorefining is 12 to 30 wt%.

42. The catalytic cracking process of claim 39, wherein the reaction temperature of the catalytic cracking reaction after the hydrorefining is 440 to 650 ℃.

43. The catalytic cracking process of claim 42, wherein the reaction temperature of the catalytic cracking reaction after the hydrorefining is 480 to 600 ℃.

44. The catalytic cracking process of claim 43, wherein the reaction temperature of the catalytic cracking reaction after the hydrorefining is 500 to 580 ℃.

45. The catalytic cracking method of claim 39, wherein the catalytic cracking reaction is carried out after the hydrorefining at a catalyst-to-oil ratio of 3 to 14.

46. The catalytic cracking process of claim 45, wherein the catalytic cracking reaction is carried out after hydrofinishing with a catalyst-to-oil ratio of 4-13.

47. The catalytic cracking method of claim 46, wherein the catalytic cracking reaction is carried out after hydrofining at a catalyst-to-oil ratio of 5 to 12.

48. The catalytic cracking process of claim 39, wherein the reaction pressure for the catalytic cracking reaction after the hydrorefining is 0.1 to 0.4 MPa.

49. The catalytic cracking process of claim 48, wherein the reaction pressure for the catalytic cracking reaction after the hydrorefining is 0.12 to 0.38 MPa.

50. The catalytic cracking process of claim 49, wherein the reaction pressure for the catalytic cracking reaction after the hydrorefining is 0.15 to 0.35 MPa.

51. The catalytic cracking process of claim 39, wherein the reaction time of the catalytic cracking reaction after the hydrorefining is 2 to 5 seconds.

52. The catalytic cracking process of claim 51, wherein the reaction time for the catalytic cracking reaction after the hydrorefining is 2.2 to 4.5 seconds.

53. The catalytic cracking process of claim 52, wherein the reaction time for the catalytic cracking reaction after the hydrorefining is 2.5 to 4 seconds.

54. The catalytic cracking process of claim 39, wherein the atomized steam subjected to the catalytic cracking reaction after the hydrorefining accounts for 0.5-4 wt% of the feed amount.

55. The catalytic cracking process of claim 54, wherein the atomized steam subjected to the catalytic cracking reaction after the hydrorefining accounts for 0.8-3.5 wt% of the feed amount.

56. The catalytic cracking process of claim 55, wherein the atomized steam subjected to the catalytic cracking reaction after the hydrorefining accounts for 1-3 wt% of the feed amount.

57. The catalytic cracking method of claim 7, wherein in the gasoline reprocessing process, the reaction temperature of hydrodesulfurization is 400-450 ℃, the reaction pressure is 2.0-4.0 MPa, the hydrogen/oil volume ratio is 1-2, and the volume space velocity is 3.5-4.5 h^-1。

58. The catalytic cracking process of claim 7, wherein the catalyst used for hydrodesulfurization during gasoline reprocessing is a nickel-molybdenum bimetallic catalyst.

59. The catalytic cracking process of claim 58, wherein the nickel-molybdenum bimetallic catalyst comprises, in mass percent: al (Al)₂O₃90-91%, 5.5-6.5% of nickel and 3-4% of molybdenum.

60. The catalytic cracking process of claim 7, wherein the distillation cut temperature is 80-120 ℃.

61. The catalytic cracking process of claim 7, wherein the aromatics extraction process employs at least one of N-methylpyrrolidone and sulfolane as an extraction solvent.

62. The catalytic cracking method of claim 7, wherein the mass ratio of the extraction solvent to the heavy fraction in the aromatic extraction process is 0.5-4: 1.

63. The catalytic cracking process of claim 7, wherein the extraction tower used in the aromatics extraction process has a top temperature of 40-100 ℃, a bottom temperature of 30-90 ℃ and a pressure of 0-2.0 MPa.