CN110551527B

CN110551527B - Method for producing gasoline rich in aromatic hydrocarbon

Info

Publication number: CN110551527B
Application number: CN201810541367.2A
Authority: CN
Inventors: 袁起民; 龚剑洪; 唐津莲; 毛安国
Original assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Current assignee: Sinopec Research Institute of Petroleum Processing; China Petroleum and Chemical Corp
Priority date: 2018-05-30
Filing date: 2018-05-30
Publication date: 2021-08-06
Anticipated expiration: 2038-05-30
Also published as: CN110551527A

Abstract

The invention relates to a method for producing gasoline rich in aromatic hydrocarbon, which comprises the following steps: (1) contacting the catalytic cracking light cycle oil with a hydrotreating catalyst and carrying out hydrotreating to obtain hydrogenated light cycle oil; (2) cutting the obtained hydrogenated light cycle oil to obtain hydrogenated light fraction, hydrogenated middle fraction and hydrogenated heavy fraction; (3) and respectively feeding the obtained hydrogenated light fraction, hydrogenated middle fraction and hydrogenated heavy fraction into the riser reactor from a lower layer nozzle, a middle layer nozzle and an upper layer nozzle which are sequentially arranged from bottom to top to contact with a catalytic cracking catalyst from the bottom of the riser reactor and perform catalytic cracking reaction from bottom to top to obtain a reaction product and a spent catalyst. The method of the invention can produce gasoline rich in aromatic hydrocarbon.

Description

Method for producing gasoline rich in aromatic hydrocarbon

Technical Field

The invention relates to a method for producing gasoline rich in aromatic hydrocarbon.

Background

With the adjustment of economic structure of China, the diesel-gasoline ratio of market consumption is reduced year by year, and the increase of diesel consumption speed lower than that of gasoline consumption speed becomes a normal state. The catalytic cracking diesel oil (also called light cycle oil) is an important byproduct of a catalytic cracking device, is large in quantity, is rich in aromatic hydrocarbon, particularly polycyclic aromatic hydrocarbon, and belongs to poor diesel oil fraction. While the quality standard of the national automotive fuel oil is continuously improved, the national V diesel oil quality standard implemented in 1 month in 2017 requires that the polycyclic aromatic hydrocarbon content in the automotive diesel oil is not more than 11%, so that the catalytic cracking light cycle oil is difficult to meet the increasingly strict diesel oil specification even after being subjected to hydrofining or hydro-upgrading. On the other hand, aromatic hydrocarbons, especially light aromatic hydrocarbons including benzene, toluene, xylene and ethylbenzene, are important petrochemical raw materials, the added value of products is high, but the domestic aromatic production raw materials are in short supply for a long time. Therefore, the catalytic conversion of the poor-quality catalytic cracking light cycle oil to produce the gasoline rich in aromatic hydrocarbon has good market application prospect.

US patent US4585545 discloses a catalytic conversion method for producing gasoline rich in monocyclic aromatic hydrocarbons by carrying out hydrotreating on a catalytic cracking light cycle oil whole fraction to obtain hydrogenated diesel oil and then carrying out catalytic cracking.

Chinese patent CN1466619A discloses a conversion method of catalytic cracking light cycle oil, which is to divide a catalytic cracking riser reactor into an upper reaction zone and a lower reaction zone, inject heavy oil into the lower reaction zone, inject hydrogenated cycle oil obtained by hydrotreating the catalytic cracking product light cycle oil into the upper reaction zone, and then crack the hydrogenated cycle oil to generate light olefins and naphtha.

Chinese patent CN104560185A discloses a catalytic conversion method for producing gasoline rich in aromatic compounds, wherein catalytic cracking light cycle oil is first cut to obtain light fraction and heavy fraction, wherein the heavy fraction is hydrotreated to obtain hydrogenated heavy fraction, and the light fraction and the hydrogenated heavy fraction are separately layered through different nozzles and enter a catalytic cracking device to produce catalytic gasoline rich in benzene, toluene and xylene.

Chinese patent CN104560187A discloses a catalytic conversion method for producing gasoline rich in aromatic hydrocarbons, wherein catalytic cracking light cycle oil is first cut to obtain light fraction and heavy fraction, wherein the heavy fraction is hydrogenated to obtain hydrogenated heavy fraction, and the light fraction and the hydrogenated heavy fraction are separately and respectively fed into different riser reactors of a catalytic cracking device, thereby producing catalytic gasoline rich in benzene, toluene and xylene.

From the above published literature, it can be found that the prior art is to hydrotreat the catalytic cracked light cycle oil whole fraction or heavy fraction and then catalytically crack the whole fraction or heavy fraction to produce gasoline rich in aromatic hydrocarbons. It must be pointed out that, no matter the catalytic cracking light cycle oil full fraction hydrogenation or the catalytic cracking light cycle oil cut heavy fraction hydrogenation, the hydrocarbon composition of the hydrogenated product has obvious difference along with the great change of the distillation range, and the reaction conditions for the catalytic conversion of the fractions with different hydrocarbon compositions to generate the gasoline rich in aromatic hydrocarbon are also obviously different. Therefore, how to make the hydrogenated fractions with obviously different hydrocarbon compositions undergo catalytic cracking reaction under respectively optimized conditions is very critical for improving the conversion rate of the catalytic cracking light cycle oil and the yield of the gasoline rich in aromatic hydrocarbon.

Disclosure of Invention

The invention aims to provide a method for producing gasoline rich in aromatic hydrocarbon, which can produce gasoline rich in aromatic hydrocarbon.

In order to achieve the above object, the present invention provides a method for producing an aromatic-rich gasoline, comprising:

(1) contacting the catalytic cracking light cycle oil with a hydrotreating catalyst and carrying out hydrotreating to obtain hydrogenated light cycle oil;

(2) cutting the obtained hydrogenated light cycle oil to obtain hydrogenated light fraction, hydrogenated middle fraction and hydrogenated heavy fraction; the initial distillation point of the hydrogenated light cycle oil is more than 80 ℃, the cut point between the hydrogenated light fraction and the hydrogenated middle fraction is 180-240 ℃, and the cut point between the hydrogenated middle fraction and the hydrogenated heavy fraction is 250-300 ℃;

(3) respectively feeding the obtained hydrogenated light fraction, hydrogenated middle fraction and hydrogenated heavy fraction into a riser reactor from a lower layer nozzle, a middle layer nozzle and an upper layer nozzle which are sequentially arranged from bottom to top to contact with a catalytic cracking catalyst from the bottom of the riser reactor and perform catalytic cracking reaction from bottom to top to obtain a reaction product and a spent catalyst;

(4) feeding the obtained spent catalyst into a regenerator for regeneration, and feeding the obtained regenerated catalyst serving as the catalytic cracking catalyst into the bottom of the riser reactor;

(5) and separating the obtained reaction product to obtain a dry gas product, a liquefied gas product, a gasoline product, a light cycle oil product and a heavy oil product.

Optionally, the aromatic content of the catalytic cracking light cycle oil is not less than 30 wt%.

Optionally, the aromatic content of the catalytic cracking light cycle oil is not less than 50 wt%.

Optionally, the hydrotreating conditions include: hydrogen partial pressure of 5.0-10.0 millionThe reaction temperature is 300 ℃ and 450 ℃, and the volume space velocity is 1.0-10.0 hours^-1The volume ratio of hydrogen to oil is 400-1600 standard cubic meters/cubic meter.

Optionally, the hydrotreating catalyst includes a carrier and an active metal component loaded on the carrier, where the carrier is at least one selected from amorphous silicon-aluminum, aluminum oxide and silicon dioxide, the active metal component is a group VIB metal and/or a group VIII non-noble metal, the group VIB metal is molybdenum and/or tungsten, and the group VIII non-noble metal is nickel and/or cobalt.

Optionally, the initial distillation point of the hydrogenated light cycle oil is greater than 150 ℃, the cut point between the hydrogenated light fraction and the hydrogenated middle fraction is 190-.

Optionally, the content of aromatics with more than two rings in the hydrogenated middle distillate is not more than 15 wt%.

Optionally, the content of aromatic hydrocarbons above bicyclo ring in the hydrogenated middle distillate is not more than 10 wt%.

Optionally, the method further includes: and (2) at least part of the light cycle oil product obtained in the step (5) is used as the catalytic cracking light cycle oil to be subjected to the hydrotreatment in the step (1).

Optionally, the riser reactor is an equal-diameter riser reactor or a reducing riser reactor.

Optionally, the residence time of the reaction oil gas in the riser reactor between the lower nozzle and the middle nozzle is 0.01-2 seconds, and the residence time of the reaction oil gas in the riser reactor between the middle nozzle and the upper nozzle is 0.03-2 seconds.

Optionally, the conditions of the catalytic cracking reaction include: the temperature at the outlet of the riser reactor is 520-680 ℃, and the micro-inverse activity of the catalytic cracking catalyst is not lower than 60;

the weight ratio of the catalytic cracking catalyst to the total raw material is 5-50, the retention time of reaction oil gas from a lower layer nozzle to the top of the riser reactor is 0.1-20 seconds, the weight ratio of water vapor to the total raw material is 0.01-0.3, and the total raw material comprises hydrogenated light fraction, hydrogenated middle fraction and hydrogenated heavy fraction.

Optionally, the catalytic cracking catalyst comprises 1-50 wt% of zeolite, 5-99 wt% of inorganic oxide and 0-70 wt% of clay based on the dry weight of the catalytic cracking catalyst, wherein the zeolite is at least one selected from the group consisting of rare earth-containing or non-containing Y zeolite, rare earth-containing or non-containing HY zeolite, rare earth-containing or non-containing USY zeolite, rare earth-containing or non-containing ZSM-5 zeolite, rare earth-containing or non-containing ZRP zeolite and rare earth-containing or non-containing Beta zeolite.

The invention has the advantages that:

1. the hydrotreated catalytic cracking light cycle oil is cut into hydrogenated light fraction, hydrogenated middle fraction and hydrogenated heavy fraction, so that the fractions with larger differences in hydrocarbon composition and reaction performance can be separated from each other, and the optimized catalytic cracking reaction conditions can be selected respectively according to the differences in the hydrocarbon composition characteristics of the fractions, and further the gasoline rich in aromatic hydrocarbon can be converted to the maximum extent.

2. Different hydrogenation fractions of catalytic cracking light cycle oil are layered and enter the riser reactor, which is beneficial to respectively optimizing reaction conditions and lightening competitive adsorption and competitive reaction effects among different hydrocarbon components, thereby being obviously beneficial to improving the conversion rate of raw materials and the yield of gasoline rich in aromatic hydrocarbon.

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

Drawings

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

FIG. 1 is a schematic flow diagram of one embodiment of the process of the present invention.

Description of the reference numerals

1 pipeline 2 pipeline 3 hydrotreater

4 line 5 fractionation plant 6 line

7 line 8 line 9 lower layer nozzle

10 middle level nozzle 11 upper layer nozzle 12 catalytic cracking device

13 line 14 line 15 line

16 pipeline

Detailed Description

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

The invention provides a method for producing gasoline rich in aromatic hydrocarbon, which comprises the following steps:

(2) cutting the obtained hydrogenated light cycle oil to obtain hydrogenated light fraction, hydrogenated middle fraction and hydrogenated heavy fraction;

According to the present invention, the catalytically cracked light cycle oil is one of the catalytically cracked products, and has a relatively high aromatic content, for example, the aromatic content of the catalytically cracked light cycle oil is not less than 30% by weight, preferably not less than 50% by weight.

In accordance with the present invention, to increase the aromatics content of the gasoline product, the hydrotreating preferably controls the saturation of polycyclic aromatics in the catalytically cracked light cycle oil, while avoiding as much as possibleMonocyclic aromatics are saturated and the hydrotreating conditions may include: hydrogen partial pressure of 5.0-10.0 MPa, reaction temperature of 300-^-1The volume ratio of hydrogen to oil is 400-1600 standard cubic meters/cubic meter. Hydrotreating catalysts are well known to those skilled in the art and may, for example, include a support, which may be at least one selected from amorphous silica, alumina and silica, and an active metal component, which may be a group VIB metal and/or a group VIII non-noble metal, which may be molybdenum and/or tungsten, supported on the support.

According to the invention, the initial distillation point of the hydrogenated light cycle oil can be more than 80 ℃, preferably more than 150 ℃, the cut point between the hydrogenated light fraction and the hydrogenated middle fraction can be 180-240 ℃, preferably 190-220 ℃, the cut point between the hydrogenated middle fraction and the hydrogenated heavy fraction can be 250-300 ℃, preferably 260-280 ℃, the content of the aromatic hydrocarbon above double rings in the hydrogenated middle fraction is preferably not more than 15 wt%, and the content of the aromatic hydrocarbon above double rings in the hydrogenated middle fraction is more preferably not more than 10 wt%.

According to the present invention, the catalytic cracking light cycle oil can be produced by the method of the present invention, and can also be produced by an external catalytic cracking unit, and preferably, the method can further comprise: and (2) at least part of the light cycle oil product obtained in the step (5) is used as the catalytic cracking light cycle oil to be subjected to the hydrotreatment in the step (1).

Riser reactors according to the present invention are well known to those skilled in the art and may be, for example, constant diameter riser reactors or variable diameter riser reactors.

The invention feeds the hydrogenated light fraction, hydrogenated middle fraction and hydrogenated heavy fraction layer by layer, can optimize reaction conditions and improve the gasoline yield and the content of aromatic hydrocarbon in the gasoline, for example, the residence time of reaction oil gas in a riser reactor between a lower layer nozzle and a middle layer nozzle can be 0.01-2 seconds, and the residence time of reaction oil gas in the riser reactor between the middle layer nozzle and an upper layer nozzle can be 0.03-2 seconds.

Catalytic cracking reactions according to the present invention are well known to those skilled in the art, for example, the conditions of the catalytic cracking reaction may include: the temperature at the outlet of the riser reactor is 520-680 ℃, preferably 540-650 ℃, the micro-inverse activity of the catalytic cracking catalyst is not less than 60, preferably not less than 65, the micro-inverse activity is determined by a RIPP 92-90 method, and the specific method can refer to petroleum chemical analysis method (RIPP test method), Yangshui and the like, 1990 edition; the weight ratio of the catalytic cracking catalyst to the total raw material can be 5-50, preferably 8-20, the residence time of the reaction oil gas from the lower layer nozzle to the top of the riser reactor can be 0.1-20 seconds, preferably 2-10 seconds, and the weight ratio of the water vapor to the total raw material can be 0.01-0.3, wherein the total raw material comprises hydrogenated light fraction, hydrogenated middle fraction and hydrogenated heavy fraction.

The catalytic cracking catalyst according to the present invention is well known to those skilled in the art, and for example, may comprise, as an active component, 1 to 50% by weight of zeolite, which may be at least one selected from the group consisting of rare earth-containing or non-containing Y zeolite, rare earth-containing or non-containing HY zeolite, rare earth-containing or non-containing USY zeolite, rare earth-containing or non-containing ZSM-5 zeolite, rare earth-containing or non-containing ZRP zeolite, and rare earth-containing or non-containing Beta zeolite, 5 to 99% by weight of an inorganic oxide, and 0 to 70% by weight of clay, based on the dry weight of the catalytic cracking catalyst.

The best mode for carrying out the invention will be further described with reference to the accompanying drawings.

The catalytic cracking light cycle oil enters a hydrotreater 3 through a pipeline 1, and hydrogen is simultaneously introduced into the hydrotreater 3 through a pipeline 2. The hydrogenated product enters a fractionating device 5 through a pipeline 4 for cutting to obtain hydrogenated light fraction, hydrogenated middle fraction and hydrogenated heavy fraction. The hydrogenated light fraction enters a catalytic cracking device 12 through a pipeline 6 and a catalytic cracking lower layer nozzle 9; the hydrogenated middle distillate enters a catalytic cracking device 12 through a pipeline 7 and a catalytic cracking middle layer nozzle 10; the hydrogenated heavy fraction enters a catalytic cracking device 12 through a pipeline 8 and a catalytic cracking upper nozzle 11. The hydrogenated light fraction, the hydrogenated middle fraction and the hydrogenated heavy fraction are subjected to catalytic cracking reaction in a catalytic cracking device 12 in the presence of a catalytic cracking catalyst, gasoline rich in aromatic hydrocarbon is obtained by separating reaction products and is led out through a pipeline 13, and the other catalytic cracking reaction product, namely light cycle oil, is led out through a pipeline 14 and enters a hydrotreating device 3 for circulation through a pipeline 15, pipelines 16 and 1. For the sake of simplicity, the outlet lines for other catalytic cracking reaction products, such as dry gas, liquefied gas, heavy oil, etc., are not shown in the figure.

The following examples further illustrate the process but are not intended to limit it.

In the examples and comparative examples, the hydrotreating reactor was a medium-sized fixed bed reactor, in which a hydrotreating catalyst having a commercial designation of RN-32V and a protectant having a commercial designation of RG-1 were loaded, and the loading volume ratio of the hydrotreating catalyst to the protectant was 95:5, which were all produced by China petrochemical catalyst division.

The physicochemical properties of the catalysts used in the catalytic cracking units of the examples and comparative examples are shown in Table 1, which is commercially available under the designation MLC-500, manufactured by China petrochemical catalyst division.

The properties of the feedstock (catalytic cracking light cycle oil) used in the examples and comparative examples are shown in table 2.

Examples

This example illustrates the use of the method provided by the present invention.

The catalytic cracking light cycle oil enters a hydrotreating reactor for hydrotreating, and the hydrotreating conditions are as follows: hydrogen partial pressure 8.0 MPa, average bed reaction temperature 350 deg.c and volume space velocity 1.0 hr^-1And the volume ratio of hydrogen to oil is 800 standard cubic meter/cubic meter, and the reaction oil gas is separated to obtain the hydrogenated light cycle oil with the initial boiling point of 155 ℃.

And the hydrogenated light cycle oil is cut through the distillation range to obtain hydrogenated light fraction, hydrogenated middle fraction and hydrogenated heavy fraction. Wherein the cutting point temperature between the hydrogenated light fraction and the hydrogenated middle fraction is 205 ℃, the cutting point temperature between the hydrogenated middle fraction and the hydrogenated heavy fraction is 270 ℃, and the content of aromatic hydrocarbons with more than two rings in the hydrogenated middle fraction is 7.2 wt%.

The hydrogenated light fraction, the hydrogenated middle fraction and the hydrogenated heavy fraction enter a riser reactor of the medium-sized catalytic cracking unit from a lower nozzle, a middle nozzle and an upper nozzle from bottom to top respectively, and the main operating conditions and the product distribution of the medium-sized catalytic cracking unit are listed in tables 3 and 4 respectively.

Comparative example 1

The same as example 1 except that: the hydrogenated light cycle oil full fraction enters from a lower nozzle of a riser reactor of the medium catalytic cracking unit, and the middle nozzle and an upper nozzle are closed. The hydrotreating conditions were the same as in example 1, the main operating conditions of the medium-sized catalytic cracking unit are shown in Table 3, and the distribution of the products after the reaction is shown in Table 4.

Comparative example 2

The same as example 1 except that: the hydrogenated light fraction and hydrogenated middle fraction are mixed and then enter from a lower nozzle of a riser reactor of the medium-sized catalytic cracking unit, the hydrogenated heavy fraction enters from an upper nozzle of the riser reactor, and a middle nozzle is closed. The hydrotreating conditions were the same as in example 1, the main operating conditions of the medium-sized catalytic cracking unit are shown in Table 3, and the distribution of the products after the reaction is shown in Table 4.

Comparative example 3

The reaction is carried out according to the method of Chinese patent CN104560185A, and the specific operation is as follows: the catalytic cracking light cycle oil is cut by the distillation range to obtain light cycle oil light fraction and light cycle oil heavy fraction, and the cutting point is 250 ℃.

And (3) feeding the light cycle oil heavy fraction into a hydrotreating reactor for hydrotreating, wherein the hydrotreating conditions are as follows: hydrogen partial pressure 8.0 MPa, average bed reaction temperature 350 deg.c and volume space velocity 1.0 hr^-1The volume ratio of hydrogen to oil is 800 standard cubic meters per cubic meter.

And respectively feeding the light fraction of the light cycle oil and the heavy fraction of the hydrogenated light cycle oil into an upper layer nozzle and a lower layer nozzle of a medium-sized catalytic cracking riser reaction device, wherein the light fraction of the light cycle oil enters the lower layer nozzle, and the heavy fraction of the hydrogenated light cycle oil enters the upper layer nozzle. The distance between the upper layer of nozzles and the lower layer of nozzles is 0.5 second of the residence time of the reaction oil gas in the distance between the two layers of nozzles. The main operating parameters of the medium-sized catalytic cracking unit were: the reaction temperature is 610 ℃, the weight ratio of the total agent oil is 20, the oil gas residence time is 7 seconds, the pressure (absolute pressure) is 0.25MPa, and the weight ratio of the water vapor to the total raw materials is 0.06. The product distribution after the reaction is shown in Table 4.

As can be seen from table 4, the comparative examples and comparative example 1 show that the method of cutting the hydrotreated catalytic cracking light cycle oil into hydrogenated light fraction, hydrogenated middle fraction and hydrogenated heavy fraction can promote the conversion of the catalytic cracking light cycle oil, obviously improve the product distribution and increase the yield of the gasoline rich in aromatic hydrocarbon; compared with the comparative example 1, the yield of the light cycle oil of the example is reduced by 5.4 percentage points, the yield of the gasoline is improved from 44.3 percent to 50.8 percent, and the yield is increased by 6.5 percentage points; the weight fractions of benzene, toluene and xylene in the gasoline are also obviously increased, the mass yield of benzene, toluene and xylene is improved from 14.32 percent to 24.58 percent, and the mass yield is increased by 10.26 percent.

It can be seen from table 4 that the comparative examples and comparative example 2 show that in comparative example 2, the yield of light cycle oil is increased by 3.6 percentage points, the yield of gasoline is decreased by 5.3 percentage points, the mass fractions of benzene, toluene and xylene in gasoline are also decreased, and the yield of benzene + toluene + xylene is decreased due to the mixed feed of the hydrogenated light fraction and hydrogenated middle fraction.

As can be seen from table 4 of comparative examples and comparative example 3, in comparative example 3, the light fraction and the hydrogenated heavy fraction of the light cycle oil are separately fed, and due to the adoption of higher reaction temperature, larger catalyst-to-oil mass ratio and longer residence time, while the yield of the light cycle oil is reduced by 2.3 percentage points, the yield of dry gas and coke is obviously increased, the yield of gasoline is reduced by 3.3 percentage points, the mass fractions of benzene, toluene and xylene in the gasoline are also obviously reduced, and the yield of benzene + toluene + xylene is reduced.

The preferred embodiments of the present invention have been described in detail with reference to the accompanying drawings, however, the present invention is not limited to the specific details of the above embodiments, and various simple modifications can be made to the technical solution of the present invention within the technical idea of the present invention, and these simple modifications are within the protective scope of the present invention.

It should be noted that the various technical features described in the above embodiments can be combined in any suitable manner without contradiction, and the invention is not described in any way for the possible combinations in order to avoid unnecessary repetition.

In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as the content of the present invention as long as it does not depart from the gist of the present invention. TABLE 1

Catalyst numbering	MLC-500
		Chemical composition, weight%
Al₂O₃	56.3
		SiO₂	37.5
RE₂O₃	3.5
		P₂O₅	0.36
Specific surface area, rice²Per gram	147
		Pore volume, ml/g	0.195
Particle size distribution,% (volume/volume)
		0-40 micron	20.1
0-40 micron	63.9
		0-40 micron	95.9
Average particle diameter, micron	67.4
		Micro-inverse activity, weight%	68

TABLE 2

Raw oil name	Catalytic cracking light cycle oil
		Density (20 deg.C), kg/m³	948.8
10% of carbon residue, by weight%	0.37
		Freezing point, DEG C	-24
Aniline point, deg.C	<30
		Average molecular weight	187
Distillation range, deg.C
		Initial boiling point	190
10% by volume	213
		30% by volume	222
50% by volume	247
		70% by volume	272
90% by volume	348
		95% by volume	363
End point of distillation	369
		Mass Spectrometry composition by weight%
Alkane hydrocarbons	10.7
		Total cycloalkanes	4.6
Total aromatic hydrocarbons	84.7
		Monocyclic aromatic hydrocarbon	31.7
Bicyclic aromatic hydrocarbons	45.0
		Total weight of	100.0

TABLE 3

TABLE 4

Item	Examples	Comparative example 1	Comparative example 2	Comparative example 3
					Product distribution, weight%
Dry gas	2.6	2.8	3.1	4.8
					Liquefied gas	14.6	14.9	15.2	16.7
Gasoline (gasoline)	50.8	44.3	45.5	47.6
					Benzene + toluene + xylene	24.58	14.32	16.35	20.08
Light cycle oil	25.8	31.2	29.4	23.5
					Heavy oil	1.8	2.3	2.1	1.6
Coke	4.4	4.5	4.7	5.8
					Total up to	100	100	100	100
The aromatic hydrocarbon composition in the gasoline is weight percent
					Benzene and its derivatives	3.73	2.74	2.82	3.26
Toluene	18.26	12.75	13.68	14.80
					Xylene	26.40	16.83	19.44	24.13

Claims

1. A process for producing an aromatic-rich gasoline, the process comprising:

(3) feeding the obtained hydrogenated light fraction, hydrogenated middle fraction and hydrogenated heavy fraction into a riser reactor from a lower layer nozzle, a middle layer nozzle and an upper layer nozzle which are sequentially arranged from bottom to top respectively to contact with a catalytic cracking catalyst from the bottom of the riser reactor and perform catalytic cracking reaction from bottom to top to obtain a reaction product and a spent catalyst, wherein the retention time of reaction oil gas in the riser reactor between the lower layer nozzle and the middle layer nozzle is 0.01-2 seconds, and the retention time of the reaction oil gas in the riser reactor between the middle layer nozzle and the upper layer nozzle is 0.03-2 seconds;

2. The process of claim 1, wherein the catalytically cracked light cycle oil has an aromatics content of not less than 30 wt.%.

3. The process of claim 1, wherein the catalytically cracked light cycle oil has an aromatics content of not less than 50 wt.%.

4. The method of claim 1, wherein the hydrotreating conditions comprise: hydrogen partial pressure of 5.0-10.0 MPa, reaction temperature of 300-^-1The volume ratio of hydrogen to oil is 400-1600 standard cubic meters/cubic meter.

5. The process of claim 1, wherein the hydrotreating catalyst comprises a support and an active metal component supported on the support, the support being at least one selected from amorphous silica-alumina, alumina and silica, the active metal component being a group VIB metal and/or a group VIII non-noble metal, the group VIB metal being molybdenum and/or tungsten, the group VIII non-noble metal being nickel and/or cobalt.

6. The method as claimed in claim 1, wherein the initial cut point of the hydrogenated light cycle oil is greater than 150 ℃, the cut point between the hydrogenated light fraction and the hydrogenated middle fraction is 190 ℃ and 220 ℃, and the cut point between the hydrogenated middle fraction and the hydrogenated heavy fraction is 260 ℃ and 280 ℃.

7. The process of claim 1, wherein the hydrogenated middle distillate fraction has a bicyclo-aromatics content of no more than 15 wt.%.

8. The process of claim 1, wherein the hydrogenated middle distillate fraction has a bicyclo-aromatics content of no more than 10 wt.%.

9. The method of claim 1, further comprising: and (2) at least part of the light cycle oil product obtained in the step (5) is used as the catalytic cracking light cycle oil to be subjected to the hydrotreatment in the step (1).

10. The method of claim 1 wherein the riser reactor is a constant diameter riser reactor or a variable diameter riser reactor.

11. The process of claim 1, wherein the conditions of the catalytic cracking reaction comprise: the temperature at the outlet of the riser reactor is 520-680 ℃, and the micro-inverse activity of the catalytic cracking catalyst is not lower than 60;

12. The process of claim 1 wherein the catalytic cracking catalyst comprises from 1 to 50 wt% of a zeolite, at least one selected from the group consisting of rare earth-containing or non-containing Y zeolite, rare earth-containing or non-containing HY zeolite, rare earth-containing or non-containing USY zeolite, rare earth-containing or non-containing ZSM-5 zeolite, rare earth-containing or non-containing ZRP zeolite, and rare earth-containing or non-containing Beta zeolite, from 5 to 99 wt% of an inorganic oxide, and from 0 to 70 wt% of a clay, based on the dry weight of the catalytic cracking catalyst.