阅读说明：本技术 一种低碳烯烃和芳烃的多产装置及方法 (High-yield device and method for low-carbon olefins and aromatic hydrocarbons ) 是由 孙世源 孟凡东 闫鸿飞 张亚西 武立宪 张瑞风 杨鑫 于 2020-07-15 设计创作，主要内容包括：本申请提供了一种低碳烯烃和芳烃的多产装置及方法,涉及石油炼制领域。多产装置包括两个提升管反应器、两个沉降器、两个分馏塔、汽油加氢脱硫装置、汽油切割蒸馏装置及芳烃抽提装置。第一提升管反应器、第一沉降器、第一分馏塔的催化汽油出口、第二提升管反应器的入料口、第二沉降器、第二分馏塔、第二分馏塔的催化汽油出口、汽油加氢脱硫装置、汽油切割蒸馏装置、汽油切割蒸馏装置的汽油重馏分出口与芳烃抽提装置依次连接。该多产装置结构简单,利用催化裂化-芳烃抽提组合工艺对劣质重油进行加工,在生产低碳烯烃和芳烃的同时,不产劣质的催化汽油和催化柴油,实现炼油装置向化工装置的转型,具有显著的经济和社会效益。(The application provides a device and a method for increasing yield of low-carbon olefins and aromatic hydrocarbons, and relates to the field of petroleum refining. The productive device comprises two riser reactors, two settlers, two fractionating towers, a gasoline hydrodesulfurization device, a gasoline cutting and distilling device and an aromatic hydrocarbon extraction device. The device comprises a first riser reactor, a first settler, a catalytic gasoline outlet of a first fractionating tower, a feeding port of a second riser reactor, a second settler, a second fractionating tower, a catalytic gasoline outlet of the second fractionating tower, a gasoline hydrodesulfurization device, a gasoline cutting and distilling device and a gasoline heavy fraction outlet of the gasoline cutting and distilling device, which are sequentially connected with an aromatic hydrocarbon extraction device. The multi-production device has a simple structure, processes the inferior heavy oil by utilizing a catalytic cracking-aromatic extraction combined process, does not produce inferior catalytic gasoline and catalytic diesel oil while producing low-carbon olefin and aromatic hydrocarbon, realizes transformation from an oil refining device to a chemical device, and has remarkable economic and social benefits.)

1. The device for increasing the yield of the low-carbon olefin and the aromatic hydrocarbon is characterized by comprising a first riser reactor, a first settler, a first fractionating tower, a second riser reactor, a second settler, a second fractionating tower, a gasoline hydrodesulfurization device, a gasoline cutting and distilling device and an aromatic hydrocarbon extraction device;

the discharge port of the first riser reactor is connected with the feed port of the first settler, the discharge port of the first settler is connected with the feed port of the first fractionating tower, the catalytic gasoline outlet of the first fractionating tower is connected with the feed port of the second riser reactor, the discharge port of the second riser reactor is connected with the feed port of the second settler, the discharge port of the second settler is connected with the feed port of the second fractionating tower, the catalytic gasoline outlet of the second fractionating tower is connected with the feed port of the gasoline hydrodesulfurization device, the discharge port of the gasoline hydrodesulfurization device is connected with the feed port of the gasoline cutting and distilling device, and the gasoline heavy fraction outlet of the gasoline cutting and distilling device is connected with the feed port of the aromatic hydrocarbon extraction device.

2. The multi-production device according to claim 1, further comprising a diesel hydrogenation device, wherein the catalytic diesel outlet of the first fractionating tower is connected to the inlet of the diesel hydrogenation device, and the outlet of the diesel hydrogenation device is connected to the inlet of the second riser reactor;

preferably, the catalytic diesel oil outlet of the second fractionating tower is connected with the feed inlet of the diesel oil hydrogenation device.

3. The multi-production device according to claim 1, wherein a gasoline light fraction outlet of the gasoline cutting and distilling device is connected with a feeding port of the second riser reactor;

preferably, the raffinate oil outlet of the aromatic hydrocarbon extraction device is connected with the feed inlet of the second riser reactor.

4. The method for producing the low-carbon olefin and the aromatic hydrocarbon in a high yield is characterized by comprising the following steps of:

performing a first catalytic cracking reaction on a heavy oil raw material in the first riser reactor by using the multi-production device as claimed in any one of claims 1 to 3, separating a reaction product and a spent catalyst in the first settler to obtain a first reaction effluent, and performing a first fractionation on the separated reaction product in the first fractionating tower to obtain a first catalytic gasoline, a first catalytic diesel oil, a first liquefied gas, a first dry gas and a first slurry oil;

carrying out a second catalytic cracking reaction on the first catalytic gasoline obtained by the first fractionation in the second riser reactor, separating a reaction product and a spent catalyst from an obtained second reaction effluent in the second settler, and carrying out a second fractionation on the separated reaction product in the second fractionating tower, wherein the fractionated product comprises second catalytic gasoline, second catalytic diesel oil, second liquefied gas, second dry gas and second slurry oil;

and hydrogenating and desulfurizing the second catalytic gasoline obtained by the second fractionation in the gasoline hydrogenation and desulfurization device, carrying out cutting and distillation on the obtained hydrogenation and desulfurization gasoline in a gasoline cutting and distillation device, and extracting the obtained gasoline heavy fraction in the aromatic hydrocarbon extraction device.

5. The high-yield process according to claim 4, wherein when the high-yield unit further comprises a diesel hydrogenation unit, the first catalytic diesel obtained from the first fractionation is hydrofined in the diesel hydrogenation unit, and then is subjected to a catalytic cracking reaction in the second riser reactor;

preferably, the second catalytic diesel obtained from the second fractionation is hydrofined in the diesel hydrogenation unit, and then is subjected to a catalytic cracking reaction in the second riser reactor.

6. The high-yield method according to claim 4, wherein the gasoline light fraction obtained by distillation in the gasoline cutting and distilling device is subjected to catalytic cracking reaction in a second riser reactor;

preferably, the residual oil extracted by the aromatic extraction device is subjected to catalytic cracking reaction in a second riser reactor.

7. The productive process as claimed in any one of claims 4 to 6, wherein the heavy oil feedstock has a hydrogen content of 9.5 to 15 wt% and a carbon residue content of not more than 8 wt%;

preferably, the mass ratio of the catalyst to the heavy oil feedstock in the first catalytic cracking reaction is 3-14: 1, more preferably 4 to 10: 1, further more preferably 5 to 9: 1;

preferably, the reaction temperature of the first catalytic cracking reaction is 440-650 ℃, more preferably 460-550 ℃, and further more preferably 480-530 ℃;

preferably, the gauge pressure of the first catalytic cracking reaction is 0.1 to 0.4MPa, more preferably 0.12 to 0.38MPa, still more preferably 0.15 to 0.35 MPa;

preferably, the time of the first catalytic cracking reaction is 2 to 5s, more preferably 2.2 to 4.5s, still more preferably 2.5 to 4 s;

preferably, the atomized steam during the first catalytic cracking reaction constitutes from 1 to 4 wt%, more preferably from 1.2 to 3.5 wg%, even more preferably from 1.5 to 3 wt% of the feed.

8. The productive process as claimed in any one of claims 4 to 6, wherein the mass ratio of the catalyst to the catalytic gasoline in the second catalytic cracking reaction is 3 to 14: 1, more preferably 4 to 13: 1, further more preferably 5 to 12: 1;

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

preferably, the gauge pressure of the second catalytic cracking reaction is 0.1 to 0.4MPa, more preferably 0.12 to 0.38MPa, still more preferably 0.15 to 0.35 MPa;

preferably, the time of the second catalytic cracking reaction is 2 to 5s, more preferably 2.2 to 4.5s, still more preferably 2.5 to 4 s;

preferably, the atomized steam during the second catalytic cracking reaction constitutes from 0.5 to 4 wt%, more preferably from 0.8 to 3.5 wg%, even more preferably from 1 to 3 wt% of the feed.

9. The productive method as claimed in any one of claims 5 to 6, wherein the reaction temperature of the hydrofining is 320-390 ℃, the hydrogen partial pressure is 5-10MPa, and the volume space velocity is 0.5-4.5h^-1The volume ratio of hydrogen to oil is 300-: 1;

preferably, the temperature of the catalytic cracking reaction of the catalytic diesel oil in the second riser reactor after the hydrofining is 440-650 ℃, more preferably 480-600 ℃, and further more preferably 500-580 ℃;

preferably, the mass ratio of the catalyst for catalytic cracking reaction of the catalytic diesel oil in the second riser reactor after hydrofining to the catalytic diesel oil is 3-14: 1, more preferably 4 to 13: 1, further more preferably 5 to 12: 1;

preferably, the gauge pressure of the catalytic cracking reaction of the catalytic diesel oil in the second riser reactor after hydrofining is 0.1-0.4MPa, more preferably 0.12-0.38MPa, and even more preferably 0.15-0.35 MPa;

preferably, the time of the catalytic cracking reaction of the catalytic diesel oil in the second riser reactor after hydrofining is 2-5s, more preferably 2.2-4.5s, and further more preferably 2.5-4 s;

preferably, the atomized water vapor of the catalytic cracking reaction of the catalytic diesel oil in the second riser reactor after hydrofinishing accounts for 0.5-4 wt%, more preferably 0.8-3.5 wt%, and still more preferably 1-3 wt% of the feeding amount.

10. The productive method as claimed in any one of claims 4 to 6, wherein the reaction temperature of hydrodesulfurization in the gasoline hydrodesulfurization device is 400-450 ℃, and the mass ratio of hydrogen to oil is 1-2: 1, the volume space velocity is 3-5h^-1；

Preferably, the catalyst used in the hydrodesulfurization process comprises a nickel molybdenum bimetallic catalyst;

preferably, the composition of the nickel-molybdenum bimetallic catalyst comprises 5.5-6.5 wt% of nickel and 3.0-4.0 wt% of molybdenum, and the balance is a carrier, more preferably, the carrier comprises alumina;

preferably, the temperature of the cutting distillation in the gasoline cutting distillation device is 80-120 ℃;

preferably, the extraction solvent used in the aromatics extraction unit comprises N-methylpyrrolidone or sulfolane;

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

preferably, the aromatic hydrocarbon extraction device is an extraction tower, the temperature of the top of the extraction tower is 40-100 ℃, the temperature of the bottom of the extraction tower is 30-90 ℃, and the pressure is 0.1-2.0 MPa.

Technical Field

The invention relates to the field of petroleum refining, in particular to a high-yield device and method for low-carbon olefin and aromatic hydrocarbon.

Background

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. The catalytic cracking process needs to be upgraded urgently to adapt to new market situations. Meanwhile, the low-carbon olefin and the light aromatic hydrocarbon are used as basic chemical raw materials, and a large market gap still exists. The catalytic cracking process for producing the low-carbon olefin and the light aromatic hydrocarbon is a feasible technical upgrading route.

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, the difficulty of blending vehicle fuel is increased, and the overall economy of the process is influenced.

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

Disclosure of Invention

The invention aims to provide a device and a method for producing light olefins and aromatic hydrocarbons in a high yield so as to overcome the technical problems.

The application can be realized as follows:

in a first aspect, the present application provides a device for increasing yields of low-carbon olefins and aromatics, comprising a first riser reactor, a first settler, a first fractionating tower, a second riser reactor, a second settler, a second fractionating tower, a gasoline hydrodesulfurization device, a gasoline cutting and distilling device, and an aromatics extraction device.

The discharge port of the first riser reactor is connected with the feed port of the first settler, the discharge port of the first settler is connected with the feed port of the first fractionating tower, the catalytic gasoline outlet of the first fractionating tower is connected with the feed port of the second riser reactor, the discharge port of the second riser reactor is connected with the feed port of the second settler, the discharge port of the second settler is connected with the feed port of the second fractionating tower, the catalytic gasoline outlet of the second fractionating tower is connected with the feed port of the gasoline hydrodesulfurization device, the discharge port of the gasoline hydrodesulfurization device is connected with the feed port of the gasoline cutting and distilling device, and the gasoline heavy fraction outlet of the gasoline cutting and distilling device is connected with the feed port of the aromatic hydrocarbon extraction device.

In an optional embodiment, the multi-production device further comprises a diesel hydrogenation device, the catalytic diesel outlet of the first fractionating tower is connected with the feed inlet of the diesel hydrogenation device, and the discharge outlet of the diesel hydrogenation device is connected with the feed inlet of the second riser reactor.

In an alternative embodiment, the catalytic diesel outlet of the second fractionation tower is connected to the feed inlet of the diesel hydrogenation unit.

In an alternative embodiment, the gasoline light fraction outlet of the gasoline cutting distillation device is connected with the feed inlet of the second riser reactor.

In an alternative embodiment, the raffinate outlet of the aromatics extraction unit is connected to the feed inlet of the second riser reactor.

In a second aspect, the present application provides a method for increasing the yield of lower olefins and aromatic hydrocarbons, comprising the steps of:

by adopting the multi-production device, heavy oil raw materials are subjected to a first catalytic cracking reaction in a first riser reactor, the obtained first reaction effluent is separated from a spent catalyst in a first settler, the separated reaction product is subjected to first fractionation in a first fractionating tower, and the fractionated products comprise first catalytic gasoline, first catalytic diesel oil, first liquefied gas, first dry gas and first slurry oil.

And carrying out second catalytic cracking reaction on the first catalytic gasoline obtained by the first fractionation in a second riser reactor, separating a reaction product and a spent catalyst from an obtained second reaction effluent in a second settler, and carrying out second fractionation on the separated reaction product in a second fractionating tower, wherein the fractionated product comprises second catalytic gasoline, second catalytic diesel oil, second liquefied gas, second dry gas and second slurry oil.

And (3) carrying out hydrodesulfurization on the second catalytic gasoline obtained by the second fractionation in a gasoline hydrodesulfurization device, carrying out cutting distillation on the obtained hydrodesulfurization gasoline in a gasoline cutting distillation device, and extracting the obtained gasoline heavy fraction in an aromatic extraction device.

In an alternative embodiment, when the multi-production unit further comprises a diesel hydrogenation unit, the first catalytic diesel oil obtained from the first fractionation is hydrofined in the diesel hydrogenation unit, and then is subjected to a catalytic cracking reaction in the second riser reactor.

In an alternative embodiment, the second catalytic diesel from the second fractionation is hydrofinished in a diesel hydrogenation unit, followed by catalytic cracking in a second riser reactor.

In an alternative embodiment, the gasoline light fraction obtained by distillation in the gasoline cutting distillation device is subjected to catalytic cracking reaction in the second riser reactor.

In an alternative embodiment, the residual oil extracted by the aromatic hydrocarbon extraction device is subjected to catalytic cracking reaction in the second riser reactor.

In an alternative embodiment, the heavy oil feedstock has a hydrogen content of 9.5 to 15 wt% and a carbon residue content of no greater than 8 wt%.

In an alternative embodiment, the mass ratio of catalyst to heavy oil feedstock in the first catalytic cracking reaction is from 3 to 14: 1, preferably 4 to 10: 1, more preferably 5 to 9: 1.

in an alternative embodiment, the reaction temperature for the first catalytic cracking reaction is 440-.

In an alternative embodiment, the gauge pressure of the first catalytic cracking reaction is in the range of from 0.1 to 0.4MPa, preferably from 0.12 to 0.38MPa, more preferably from 0.15 to 0.35 MPa.

In an alternative embodiment, the time of the first catalytic cracking reaction is 2 to 5s, preferably 2.2 to 4.5s, more preferably 2.5 to 4 s.

In an alternative embodiment, the atomized steam during the first catalytic cracking reaction represents from 1 to 4 wt%, preferably from 1.2 to 3.5 wg%, more preferably from 1.5 to 3 wt% of the feed.

In an alternative embodiment, the mass ratio of catalyst to catalytic gasoline in the second catalytic cracking reaction is 3-14: 1, preferably 4 to 13: 1, more preferably 5 to 12: 1.

in an alternative embodiment, the reaction temperature for the second catalytic cracking reaction is 440-.

In an alternative embodiment, the gauge pressure of the second catalytic cracking reaction is in the range of from 0.1 to 0.4MPa, preferably from 0.12 to 0.38MPa, more preferably from 0.15 to 0.35 MPa.

In an alternative embodiment, the time for the second catalytic cracking reaction is 2 to 5s, preferably 2.2 to 4.5s, more preferably 2.5 to 4 s.

In an alternative embodiment, the atomized steam during the second catalytic cracking reaction represents from 0.5 to 4 wt%, preferably from 0.8 to 3.5 wg%, more preferably from 1 to 3 wt% of the feed.

In an alternative embodiment, the reaction temperature of the hydrofining is 320-390 ℃, the hydrogen partial pressure is 5-10MPa, and the volume space velocity is 0.5-4.5h^-1The volume ratio of hydrogen to oil is 300-: 1.

in an alternative embodiment, the temperature of the catalytic cracking reaction of the catalytic diesel in the second riser reactor after the hydrofinishing is 440-650 ℃, preferably 480-600 ℃, and more preferably 500-580 ℃.

In an alternative embodiment, the mass ratio of the catalyst for catalytic cracking reaction of the catalytic diesel oil in the second riser reactor after hydrofining to the catalytic diesel oil is 3-14: 1, preferably 4 to 13: 1, more preferably 5 to 12: 1.

in an alternative embodiment, the catalytic cracking reaction of the catalytic diesel after hydrofinishing in the second riser reactor has a gauge pressure of 0.1 to 0.4MPa, preferably 0.12 to 0.38MPa, more preferably 0.15 to 0.35 MPa.

In an alternative embodiment, the catalytic cracking reaction of the catalytic diesel after hydrofinishing is carried out in the second riser reactor for a period of time ranging from 2 to 5s, preferably from 2.2 to 4.5s, more preferably from 2.5 to 4 s.

In an alternative embodiment, the atomized water vapor of the catalytic cracking reaction of the catalytic diesel after hydrofinishing in the second riser reactor is 0.5 to 4 wt%, preferably 0.8 to 3.5 wt%, more preferably 1 to 3 wt% of the feed.

In an alternative embodiment, the reaction temperature of hydrodesulfurization in the gasoline hydrodesulfurization device is 400-450 ℃, and the mass ratio of hydrogen to oil is 1-2: 1, the volume space velocity is 3-5h^-1。

In an alternative embodiment, the catalyst used in the hydrodesulfurization process comprises a nickel molybdenum bimetallic catalyst.

In an alternative embodiment, the nickel-molybdenum bimetallic catalyst comprises a composition of 5.5 to 6.5 wt% nickel and 3.0 to 4.0 wt% molybdenum, with the balance being the support. Preferably, the carrier comprises alumina.

In an alternative embodiment, the temperature of the cutting distillation in the gasoline cutting distillation unit is between 80 and 120 ℃.

In an alternative embodiment, the extraction solvent used in the aromatics extraction unit comprises N-methylpyrrolidone or sulfolane.

In an alternative embodiment, the mass ratio of extraction solvent to heavy fraction of gasoline is between 0.5 and 4: 1.

in an alternative embodiment, the aromatics extraction unit is an extraction column having a top temperature of 40-100 deg.C, a bottom temperature of 30-90 deg.C, and a pressure of 0.1-2 MPa.

The beneficial effect of this application includes:

the multi-production device for the low-carbon olefin and the aromatic hydrocarbon has a simple structure, processes the inferior heavy oil by matching the double-riser reactor, the double settler, the double-fractionating tower, the gasoline hydrodesulfurization device, the gasoline cutting distillation device and the aromatic hydrocarbon extraction device and utilizing the catalytic cracking-aromatic hydrocarbon extraction combined process, does not produce the inferior catalytic gasoline and catalytic diesel oil while producing the low-carbon olefin and the aromatic hydrocarbon, realizes the transformation of an oil refining device to a chemical device, and has remarkable economic and social benefit matching.

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 structural diagram of a multi-production apparatus for low-carbon olefins and aromatics provided by the present application.

Icon: 1-heavy oil feedstock; 2-a first riser reactor; 3-a first settler; 4-a first reaction effluent; 5-a first fractionation column; 6-first dry gas; 7-first catalytic gasoline; 8-first catalytic diesel; 9-a first slurry oil; 10-diesel hydrogenation unit; 11-hydrocatalytic diesel; 12-a second riser reactor; 13-a second settler; 14-a second reaction effluent; 15-a second fractionation column; 16-second dry gas; 17-a second catalytic gasoline; 18-second catalytic diesel; 19-a second slurry oil; 20-a gasoline hydrodesulfurization unit; 21-hydrodesulfurized gasoline; 22-gasoline cutting distillation unit; 23-gasoline light ends; 24-gasoline heavy fraction; 25-aromatics extraction unit; 26-raffinate oil; 27-oil draw-off.

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.

The following provides a specific description of the apparatus and method for producing light olefins and aromatics in high yield.

As shown in fig. 1, the present application provides a high yield device for low carbon olefins and aromatics, which includes a first riser reactor 2, a first settler 3, a first fractionating tower 5, a second riser reactor 12, a second settler 13, a second fractionating tower 15, a gasoline hydrodesulfurization device 20, a gasoline cutting and distilling device 22, and an aromatics extraction device 25.

The discharge port of the first riser reactor is connected with the feed port of the first settler 3, the discharge port of the first settler 3 is connected with the feed port of the first fractionating tower 5, the catalytic gasoline outlet of the first fractionating tower 5 is connected with the feed port of the second riser reactor 12, the discharge port of the second riser reactor 12 is connected with the feed port of the second settler 13, the discharge port of the second settler 13 is connected with the feed port of the second fractionating tower 15, the catalytic gasoline outlet of the second fractionating tower 15 is connected with the feed port of the gasoline hydrodesulfurization device 20, the discharge port of the gasoline hydrodesulfurization device 20 is connected with the feed port of the gasoline cutting and distilling device 22, and the gasoline heavy fraction 24 outlet of the gasoline cutting and distilling device 22 is connected with the feed port of the aromatic extraction device 25.

In an optional embodiment, the multi-production apparatus further comprises a diesel hydrogenation apparatus 10, the catalytic diesel outlet of the first fractionation tower 5 is connected to the feed inlet of the diesel hydrogenation apparatus 10, and the discharge outlet of the diesel hydrogenation apparatus 10 is connected to the feed inlet of the second riser reactor 12.

In an alternative embodiment, the catalytic diesel outlet of the second fractionator 15 is connected to the feed inlet of the diesel hydrogenation unit 10.

In an alternative embodiment, the outlet of the gasoline light fraction 23 of the gasoline cut distillation unit 22 is connected to the inlet of the second riser reactor 12.

In an alternative embodiment, the raffinate 26 outlet of aromatics extraction unit 25 is connected to the inlet of second riser reactor 12.

The method for increasing the yield of the low-carbon olefin and the aromatic hydrocarbon by adopting the device comprises the following steps:

the heavy oil raw material 1 is subjected to a first catalytic cracking reaction in a first riser reactor 2, the obtained first reaction effluent 4 is separated from a spent catalyst in a first settler 3, the separated reaction product is subjected to first fractionation in a first fractionating tower 5, and the fractionated product comprises first catalytic gasoline 7, first catalytic diesel oil 8, first liquefied gas, first dry gas 6 and first slurry oil 9. The spent catalyst separated in the first settler 3 may be introduced into an external regenerator (not shown) for regeneration.

The gasoline fraction (first catalytic gasoline 7) obtained by the first fractionation is subjected to a second catalytic cracking reaction in a second riser reactor 12, the obtained second reaction effluent 14 is subjected to separation of a reaction product and a spent catalyst in a second settler 13, the separated reaction product is subjected to a second fractionation in a second fractionating tower 15, and the products obtained by the fractionation comprise second catalytic gasoline 17, second catalytic diesel oil 18, second liquefied gas, second dry gas 16 and second slurry oil 19. Similarly, the spent catalyst separated in the second precipitator 13 can also enter an external regenerator (not shown) for regeneration.

The gasoline fraction (second catalytic gasoline 17) obtained from the second fractionation is hydrodesulfurized in a gasoline hydrodesulfurizer 20 to remove sulfur from the gasoline and saturate a part of acetylene hydrocarbons. The hydrodesulfurized gasoline 21 obtained after hydrogenation is cut and distilled in a gasoline cutting and distilling device 22 to separate light fraction and heavy fraction. Wherein, the obtained gasoline heavy fraction 24 is subjected to aromatic extraction in an aromatic extraction device 25, and light aromatic hydrocarbons such as BTX are extracted as products to be discharged from the aromatic extraction device 25.

In an alternative embodiment, when the multi-production unit further comprises a diesel hydrogenation unit 10, the diesel fraction (first catalytic diesel oil 8) obtained from the first fractionation is subjected to hydrofinishing in the diesel hydrogenation unit 10, and then subjected to catalytic cracking reaction in the second riser reactor 12.

In an alternative embodiment, the diesel fraction from the second fractionation (second catalytic diesel 18) is hydrofinished in a diesel hydrogenation unit 10, followed by a catalytic cracking reaction in the second riser reactor 12.

Preferably, the diesel oil fraction (second catalytic diesel oil 18) obtained from the second fractionation and the diesel oil fraction (first catalytic diesel oil 8) obtained from the first fractionation are mixed, and then hydrofinished in the diesel oil hydrogenation apparatus 10, and then subjected to catalytic cracking reaction in the second riser reactor 12.

In an alternative embodiment, the gasoline light fraction 23 obtained by distillation in the gasoline cut distillation unit 22 is subjected to catalytic cracking reaction in the second riser reactor 12.

Preferably, the gasoline light fraction 23 obtained by distillation in the gasoline cutting and distilling apparatus 22 is mixed with the gasoline fraction (first catalytic gasoline 7) separated from the first fractionating tower 5, and then enters the second riser reactor 12 for catalytic cracking reaction.

In an alternative embodiment, the residual oil extracted by the aromatics extraction device 25 is subjected to catalytic cracking reaction in the second riser reactor 12.

Preferably, the residual oil extracted by the aromatic extraction device 25 is mixed with the gasoline fraction (first catalytic gasoline 7) separated by the first fractionating tower 5, and then enters the second riser reactor 12 together for catalytic cracking reaction.

In alternative embodiments, the heavy oil feedstock 1 can have a hydrogen content of 9.5 to 15 wt%, such as 9.5 wt%, 10 wt%, 12 wt%, or 15 wt%, etc., and a carbon residue content of no greater than 8 wt%, such as 8 wt%, 5 wt%, or 3 wt%, etc.

In an alternative embodiment, the mass ratio of catalyst to heavy oil feedstock 1 in the first catalytic cracking reaction may be 3-14: 1, preferably 4 to 10: 1, more preferably 5 to 9: 1, such as 5: 1. 6: 1. 7: 1. 8: 1 or 9: 1, etc. Exceeding the above conditions easily leads to deterioration of product distribution, increase in yield of undesired products, and increase in difficulty in operation of the apparatus.

In an alternative embodiment, the reaction temperature of the first catalytic cracking reaction is 440-.

In an alternative embodiment, the gauge pressure of the first catalytic cracking reaction is in the range of from 0.1 to 0.4MPa, preferably from 0.12 to 0.38MPa, more preferably from 0.15 to 0.35MPa, such as 0.15MPa, 0.2MPa, 0.25MPa, 0.3MPa or 0.35MPa, and the like.

In an alternative embodiment, the time of the first catalytic cracking reaction is 2 to 5s, preferably 2.2 to 4.5s, more preferably 2.5 to 4s, such as 2.5s, 3s, 3.5s or 4s, etc.

In an alternative embodiment, the atomized steam during the first catalytic cracking reaction comprises from 1 to 4 wt%, preferably from 1.2 to 3.5 wg%, more preferably from 1.5 to 3 wt%, such as 1.5 wt%, 2 wt%, 2.5 wt% or 3 wt%, etc., of the feed.

The catalyst used in the first catalytic cracking process may be a conventional catalytic cracking catalyst.

In an alternative embodiment, the mass ratio of catalyst to catalytic gasoline in the second catalytic cracking reaction is 3-14: 1, preferably 4 to 13: 1, more preferably 5 to 12: 1, such as 5: 1. 6: 1. 7: 1. 8: 1. 9: 1. 10: 1. 11: 1 or 12: 1, etc.

In an alternative embodiment, the reaction temperature of the second catalytic cracking reaction is 440-650 deg.C, preferably 480-600 deg.C, more preferably 500-580 deg.C, such as 500 deg.C, 520 deg.C, 550 deg.C, 560 deg.C or 580 deg.C.

In an alternative embodiment, the gauge pressure of the second catalytic cracking reaction is in the range of from 0.1 to 0.4MPa, preferably from 0.12 to 0.38MPa, more preferably from 0.15 to 0.35MPa, such as 0.15MPa, 0.2MPa, 0.25MPa, 0.3MPa or 0.35MPa, and the like.

In an alternative embodiment, the second catalytic cracking reaction is carried out for a period of time in the range of 2 to 5s, preferably 2.2 to 4.5s, more preferably 2.5 to 4s, such as 2.5s, 3s, 3.5s or 4s, etc.

In an alternative embodiment, the atomized steam during the second catalytic cracking reaction comprises from 0.5 to 4 wt%, preferably from 0.8 to 3.5 wg%, more preferably from 1 to 3 wt%, such as 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, or 3 wt%, etc., of the feed.

The catalyst used in the second catalytic cracking process may also be a conventional catalytic cracking catalyst.

In the application, the catalytic diesel oil is subjected to hydrofining before catalytic cracking reaction, so that aromatic hydrocarbons with more than two rings in the diesel oil can be converted into saturated hydrocarbons or monocyclic aromatic hydrocarbons. The catalyst used in the hydrofining process can be a conventional hydrofining catalyst.

In an alternative embodiment, the reaction temperature of the hydrofining is 320-390 ℃, the hydrogen partial pressure is 5-10MPa, and the volume space velocity is 0.5-4.5h^-1The volume ratio of hydrogen to oil is 300-: 1, such as 300: 1. 400: 1. 500: 1. 600: 1. 700: 1 or 800: 1, etc.

In an alternative embodiment, the temperature of the catalytic cracking reaction of the catalytic diesel after the hydrofinishing in the second riser reactor 12 is 440-650 deg.C, preferably 480-600 deg.C, more preferably 500-580 deg.C, such as 500 deg.C, 520 deg.C, 550 deg.C, 560 deg.C or 580 deg.C.

In an alternative embodiment, the mass ratio of the catalyst for catalytic cracking reaction of the catalytic diesel after hydrofining in the second riser reactor 12 to the catalytic diesel is 3-14: 1, preferably 4 to 13: 1, more preferably 5 to 12: 1, such as 5: 1. 6: 1. 7: 1. 8: 1. 9: 1. 10: 1. 11: 1 or 12: 1, etc.

In an alternative embodiment, the catalytic cracking reaction of the catalytic diesel after hydrofinishing is carried out in the second riser reactor 12 at a gauge pressure of 0.1 to 0.4MPa, preferably 0.12 to 0.38MPa, more preferably 0.15 to 0.35MPa, such as 0.15MPa, 0.2MPa, 0.25MPa, 0.3MPa or 0.35MPa, etc.

In an alternative embodiment, the catalytic cracking reaction of the catalytic diesel oil in the second riser reactor 12 after hydrofinishing is carried out for 2 to 5s, preferably 2.2 to 4.5s, more preferably 2.5 to 4s, such as 2.5s, 3s, 3.5s or 4 s.

In an alternative embodiment, the atomized steam of the catalytic cracking reaction of the catalytic diesel after hydrofinishing in the second riser reactor 12 is 0.5-4 wt%, preferably 0.8-3.5 wt%, more preferably 1-3 wt%, such as 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt% or 3 wt% of the feed.

In an alternative embodiment, the reaction temperature of hydrodesulfurization in the gasoline hydrodesulfurization unit 20 may be 400-: 1, such as 1:1, 1.5:1 or 2:1, and the like, and the volume space velocity can be 3-5h^-1E.g. 3h^-1、4h^-1Or 5h^-1And the like.

In an alternative embodiment, the catalyst used in the hydrodesulfurization process comprises a nickel molybdenum bimetallic catalyst. Molybdenum is used as an active center, so that the desulfurization activity is stronger, and nickel is used as an auxiliary agent, so that the stability of the catalyst can be improved. Bimetallic catalysts have higher activity and stability relative to single metal catalysts. In an alternative embodiment, the nickel-molybdenum bimetallic catalyst may comprise a composition comprising 5.5 to 6.5 wt% (preferably 6 wt%) nickel and 3.0 to 4.0 wt% (preferably 3.5 wt%) molybdenum, with the balance being the support. The carrier may include alumina, silica, active carbon, lead silicate, active clay, molecular sieve, etc.

In alternative embodiments, the temperature of the cutting distillation in the gasoline cutting distillation apparatus 22 is 80-120 ℃, such as 80 ℃, 100 ℃ or 120 ℃ and the like.

In an alternative embodiment, the extraction solvent used in aromatics extraction unit 25 comprises N-methylpyrrolidone or sulfolane.

In an alternative embodiment, the mass ratio of extraction solvent to the heavy fraction 24 of gasoline is between 0.5 and 4: 1, such as 0.5: 1. 1: 1. 2: 1. 3: 1 or 4: 1, etc.

In alternative embodiments, the aromatics extraction unit 25 is an extraction column, and the overhead temperature of the extraction column can be from 40 ℃ to 100 ℃, such as 40 ℃, 50 ℃, 60 ℃, 80 ℃, or 100 ℃, and the like. The temperature of the bottom of the column can be 30-90 deg.C, such as 30 deg.C, 50 deg.C, 70 deg.C or 90 deg.C. The pressure may be 0.1-2.0MPa, such as 0.1MPa, 0.5MPa, 1MPa, 1.5MPa or 2 MPa.

In summary, the method utilizes the catalytic cracking-aromatic extraction combined process to process the inferior heavy oil, produces low-carbon olefin and aromatic hydrocarbon, does not produce inferior catalytic gasoline and catalytic diesel oil, realizes transformation of an oil refining device to a chemical device, and has remarkable economic and social benefits.