CN112143522B

CN112143522B - Hydrogenation method and system for production chemical material

Info

Publication number: CN112143522B
Application number: CN201910562591.4A
Authority: CN
Inventors: 赵广乐; 赵阳; 莫昌艺; 毛以朝; 董松涛
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: 2019-06-26
Filing date: 2019-06-26
Publication date: 2022-03-11
Anticipated expiration: 2039-06-26
Also published as: CN112143522A

Abstract

A hydrogenation method and a hydrogenation system for producing chemical materials are characterized in that a mixed raw material rich in aromatic diesel oil fraction and wax oil fraction enters a first hydrogenation reaction zone, and is sequentially contacted with a hydrofining catalyst and a hydrocracking catalyst I for reaction, a reaction effluent is separated by a first high-pressure separator, an obtained first gas-phase material flow enters a second hydrogenation reaction zone, and is contacted with a hydrocracking catalyst II for reaction, the separated first liquid-phase material flow and the reaction effluent of the second hydrogenation reaction zone are separated together for obtaining light naphtha fraction, heavy naphtha fraction, diesel oil fraction and tail oil fraction, and the diesel oil fraction is recycled to the second hydrogenation reaction zone. By adopting the method and the system provided by the invention, the wax oil fraction which is blended with a large proportion of aromatic hydrocarbon-rich diesel oil fraction can be processed, and the heavy naphtha fraction with high aromatic hydrocarbon potential content and the tail oil fraction with high hydrogen content can be obtained with high yield and high selectivity.

Description

Hydrogenation method and system for production chemical material

Technical Field

The present invention relates to a hydrocarbon oil cracking method for obtaining low boiling point fraction in the presence of hydrogen, and more specifically, to a hydrogenation method and system for producing chemical materials from mixed raw materials.

Background

Along with the aggravation of the process of the heavy oil and the inferior oil of the crude oil, the quality of the catalytic cracking diesel oil is increasingly poor, the yield is increased year by year, and the catalytic cracking diesel oil accounts for about one third of the share of commodity diesel oil in China. At present, in order to extract more light oil products from crude oil, refineries continuously improve the processing capacity and processing depth of a catalytic cracking device, so that the quality of catalytic cracking diesel oil is further deteriorated, mainly manifested by high aromatic hydrocarbon content, high content of impurities such as sulfur, nitrogen and the like, and low cetane number. Meanwhile, along with the increasing strictness of environmental legislation, the cetane number of the national VI automotive diesel oil standard is not less than 51, the sulfur content is not more than 10 mu g/g, and the polycyclic aromatic hydrocarbon mass content is not more than 7%. In recent years, the consumption of diesel oil enters a peak platform area, the reduction of diesel-gasoline ratio year by year becomes a great trend, and the demand of reducing the diesel oil, especially poor-quality diesel oil, is more urgent.

Worldwide propylene demand is expected to continue to increase over the next 20 years, with chinese propylene demand increasing beyond the world's average. Propylene is second only to ethylene an important petrochemical feedstock. Steam cracking and catalytic cracking are main technical processes of propylene in China, the property of raw materials is a main influence factor influencing the yield of the propylene, and along with the aggravation of the heavy deterioration trend of the raw materials, the key for improving the property of the cracking raw materials is to improve the yield of the propylene.

The catalytic diesel oil processing means mainly comprises two types of hydrofining and hydrocracking. The conventional hydrofining process is adopted to treat the catalytic diesel oil, although the impurities such as sulfur, nitrogen and the like in the diesel oil can be effectively removed, the cetane number of the diesel oil product is improved in a limited range. According to the trend of upgrading oil quality, the automotive diesel fuel standard is mainly shifted to the control of the oil structure composition by sulfur reduction, especially polycyclic aromatic hydrocarbons. Therefore, the catalytic diesel with the aromatic hydrocarbon content of more than 80 percent and the polycyclic aromatic hydrocarbon content of more than 60 percent is increasingly difficult to be added into a diesel pool by the conventional means.

The hydrocracking means can convert the catalytic diesel fraction into light heavy naphtha or gasoline fraction, but the existing industrial device for converting the catalytic diesel into the gasoline fraction generally has the problems of high technical level, short operation period, severe device operation and the like.

CN103805245B discloses a combined hydrogenation method of hydrocracking and hydrodearomatization. The poor-quality catalytic cracking diesel and hydrogen are hydrofined in a gas-liquid countercurrent mode; carrying out hydrogenation dearomatization reaction on refined oil in the presence of a noble metal catalyst; carrying out hydrocracking pretreatment reaction on the wax oil and hydrogen, and carrying out hydrocracking reaction after mixing the hydrocracking pretreatment effluent and the hydrodearomatization effluent; separating and fractionating the hydrocracking effluent to obtain different fraction products; wherein the cracking tail oil is recycled to the hydrogenation dearomatization reactor. The method adopts noble metal catalyst to fully saturate and catalyze aromatic hydrocarbon in the diesel oil, and improves the yield and product quality of the middle distillate oil.

CN102994147B discloses a method for producing middle distillate by medium pressure hydrocracking of heavy oil. The method takes vacuum wax oil or vacuum wax oil with partial catalytic diesel oil as raw material to produce diesel oil by hydrogenation, adopts a fixed bed two-stage hydrocracking process, and fills a special hydrofining catalyst in a first-stage reactor and a special hydrocracking catalyst in a second-stage reactor.

CN1955257B discloses a hydrocracking method for producing chemical raw materials, which comprises the steps of mixing poor quality catalytic cracking diesel oil and heavy hydrocracking raw materials in proportion, and then carrying out hydrotreating and hydrocracking to obtain chemical raw materials such as heavy naphtha, tail oil and the like.

Disclosure of Invention

The invention aims to provide a hydrogenation method and a hydrogenation system for producing chemical materials from mixed raw materials on the basis of the prior art. In particular to a method for solving the problems that when the prior art is used for processing a mixed raw material which is rich in aromatic hydrocarbon diesel oil and is doped with a large proportion of aromatic hydrocarbon diesel oil, the yield of heavy naphtha fraction and the potential content of aromatic hydrocarbon in the product are low, and the quality of tail oil is reduced.

The invention provides a hydrogenation method for a production chemical material, which comprises the following steps: the mixed raw material rich in the aromatic hydrocarbon diesel fraction and the wax oil fraction enters a first hydrogenation reaction zone, and is sequentially contacted with a hydrofining catalyst and a hydrocracking catalyst I for reaction, the reaction effluent of the first hydrogenation reaction zone enters a first high-pressure separator for separation, the separated first gas-phase material flow enters a second hydrogenation reaction zone, and is contacted with a hydrocracking catalyst II for reaction, the first liquid-phase material flow separated by the first high-pressure separator and the reaction effluent of the second hydrogenation reaction zone enter a second high-pressure separator and a fractionation zone in sequence, and a light naphtha fraction, a heavy naphtha fraction, a diesel fraction and a tail oil fraction are obtained after separation, and the diesel fraction is recycled to the second hydrogenation reaction zone.

In the invention, the mixed raw material consists of aromatic hydrocarbon-rich diesel oil fraction and wax oil fraction, and the mass fraction of the aromatic hydrocarbon-rich diesel oil fraction is 30-80% on the basis of the whole mixed raw material.

Preferably, the aromatic-rich diesel fraction has a density of 0.90g/cm³～0.99g/cm³The distillation range is 165-400 ℃, and the aromatic hydrocarbon content is at least 60 weight percentAmount%; the fraction rich in aromatic diesel oil is further preferably catalytic cracking diesel oil.

In a preferred case, the wax oil fraction is one or more selected from vacuum wax oil, coker wax oil and deasphalted oil, and the density of the wax oil fraction is 0.88g/cm³～0.97g/cm³The distillation range is 300-600 ℃.

In the invention, the mixed raw material and hydrogen are mixed and then enter a first hydrogenation reaction zone, and then contact with a hydrofining catalyst to carry out hydrodesulfurization, hydrodenitrogenation, olefin saturation, partial aromatic saturation and other reactions. The hydrofined mixed raw material directly contacts with a hydrocracking catalyst I, and under the preferable condition, the hydrocracking catalyst I is a hydrocracking catalyst containing amorphous silica-alumina, mainly generates a selective ring-opening reaction, reduces chain scission reaction to the maximum extent, maintains refined wax oil fraction, and improves the hydrocarbon structure of the refined wax oil fraction, so that the liquid phase material flow of the first hydrogenation reaction zone has the characteristics of high content of paraffin, cycloparaffin and dicycloalkane and high content of hydrogen. In addition, the aromatic hydrocarbon content of the diesel oil fraction rich in aromatic hydrocarbon in the mixed raw material is higher, the aromatic hydrocarbon content is usually more than 60%, and the aromatic hydrocarbon content over double rings is more than 40%. Fractions above 300 ℃ in the aromatic hydrocarbon-rich diesel fraction raw material mainly comprise bicyclic and tricyclic aromatic hydrocarbons, and after the polycyclic aromatic hydrocarbons are subjected to hydrogenation saturation, the boiling point reduction range is 20-50 ℃ according to the difference of hydrogenation saturation depths.

In a preferred case, in order to ensure the activity and stability of the downstream hydrocracking catalyst II containing the molecular sieve, the organic nitrogen content is less than 20 mug/g based on the liquid effluent of the first hydrogenation reaction zone.

In the invention, the reaction effluent of the first hydrogenation reaction zone enters the first high-pressure separator and is flashed in the first high-pressure separator, gases such as lighter hydrocarbon oil, hydrogen-rich gas and the like are taken as a first gas phase material flow in a gaseous state and discharged from a gas phase outlet of the first high-pressure separator, and heavier hydrocarbon oil is taken as a first liquid phase material flow in a liquid state and discharged from a liquid phase outlet of the first high-pressure separator. Preferably, the temperature of the first high-pressure separator is 300 to 370 ℃, more preferably 320 to 350 ℃. At the operating temperature of the first high-pressure separator, the hydrogenated aromatic-rich diesel fraction is almost all discharged in a gas phase from the gas-phase outlet of the first high-pressure separator, and the hydrogenated wax oil fraction is almost all discharged in a liquid phase from the liquid-phase outlet of the first high-pressure separator.

In a preferred aspect, the reaction conditions of the first hydrogenation reaction zone are: the hydrogen partial pressure is 6.0-20.0 MPa, the reaction temperature is 300-450 ℃, and the volume ratio of hydrogen to oil is 400-2000 Nm³/m³Taking the mixed raw material as a fresh raw material, wherein the liquid hourly space velocity is 0.2-3.0 h based on the fresh raw material^-1。

In the invention, the separated first gas phase material flow enters a second hydrogenation reaction zone and contacts with a hydrocracking catalyst II to carry out hydrocracking reaction. The first gaseous stream is predominantly a hydrogenated naphtha fraction and a diesel fraction having a dry point within the range of from 300 ℃ to 370 ℃, and therefore the second hydrogenation reaction zone is preferably operated at process conditions suitable for the conversion of the diesel fraction to a heavy naphtha fraction. In addition, because the gas components in the reaction effluent of the first hydrogenation reaction zone also directly enter the second hydrogenation reaction zone, the reaction atmosphere of the second hydrogenation reaction zone contains all hydrogen sulfide and ammonia generated after the hydrogen sulfide and ammonia are removed in the first hydrogenation reaction zone through hydrodesulfurization and hydrodenitrogenation reactions. The higher ammonia concentration in the second hydrogenation reaction zone has the effect of inhibiting excessive secondary cracking, is further beneficial to converting the diesel fraction into the heavy naphtha fraction with high selectivity, reducing the yield of dry gas, liquefied gas and light naphtha fraction, and being capable of keeping the ring structure in the heavy naphtha fraction to the maximum extent to obtain the heavy naphtha fraction with high aromatic hydrocarbon potential content, wherein the heavy naphtha fraction is a high-quality catalytic reforming raw material.

In a preferred aspect, the reaction conditions of the second hydrogenation reaction zone are: the hydrogen partial pressure is 6.0-20.0 MPa, the reaction temperature is 300-420 ℃, and the volume ratio of hydrogen to oil is 300-1200 Nm³/m³The liquid hourly space velocity is 0.5-8.0 h^-1。

In a preferred embodiment of the present invention, the first liquid phase stream separated by the first high-pressure separator is divided into two paths, and one path is recycled to the first hydrogenation reaction zone, and the recycled first liquid phase stream accounts for 1-80% of the mixed raw material by mass. The other path is mixed with the reaction effluent of the second hydrogenation reaction zone and enters a second high-pressure separator. Gas-liquid separation is carried out in the second high-pressure separator to obtain a second gas-phase material flow and a second liquid-phase material flow. Preferably, the temperature of the second high-pressure separator is 150-300 ℃, and more preferably 220-260 ℃. And the obtained second liquid phase material flow enters a fractionating zone, light naphtha fraction, heavy naphtha fraction, diesel oil fraction and tail oil fraction are obtained after separation, and the diesel oil fraction is recycled to the second hydrogenation reaction zone.

In a preferred aspect, the present invention monitors the product quality of the tail oil fraction and improves the product quality of the tail oil fraction by recycling the first liquid phase stream to the first hydrogenation reaction zone. In a preferred embodiment, when the hydrogen content of the tail oil fraction is less than or equal to 13.5 wt%, at least a part of the first liquid phase stream is recycled to the first hydrogenation reaction zone, and the recycled first liquid phase stream accounts for 1-50% of the mixed raw material by mass.

In a preferred case, the second gaseous stream separated by the second high-pressure separator is recycled to the first hydrogenation reaction zone as recycle hydrogen after removing hydrogen sulfide and ammonia.

In the invention, a hydrofining catalyst is filled at the upstream of a first hydrogenation reaction zone, a hydrocracking catalyst I is filled at the downstream, and a hydrocracking catalyst II is filled in a second hydrogenation reaction zone; preferably, the volume ratio of the hydrocracking catalyst I to the hydrocracking catalyst II is 2: 1-1: 5; the volume ratio of the hydrorefining catalyst to the volume ratio of the hydrocracking catalyst I to the hydrocracking catalyst II is 5: 1-1: 10.

In a preferred case, the hydrofinishing catalyst is a catalyst of at least one group VIII metal component and at least one group VIB metal component supported on a carrier. More preferably, the hydrofining catalyst is calculated by oxides and based on the hydrofining catalyst, the content of the VIII group metal component is 1-10 wt%, and the content of the VIB group metal component is 10-45 wt%; the VIII group metal component is cobalt and/or nickel, and the VIB group metal component is molybdenum and/or tungsten.

In a preferred case, the hydrocracking catalyst I comprises a carrier and a hydrogenation metal active component loaded on the carrier, wherein the carrier consists of alumina and amorphous silica-alumina; the hydrogenation metal active component is selected from at least one VIII group metal component and at least one VIB group metal component.

More preferably, the hydrocracking catalyst I comprises the following components in terms of oxides based on the whole hydrocracking catalyst I: 20 to 70 weight percent of alumina, 20 to 70 weight percent of amorphous alumina-silicon oxide, 10 to 35 weight percent of VIB group metal component and 1 to 15 weight percent of VIII group metal; the VIII group metal component is cobalt and/or nickel, and the VIB group metal component is molybdenum and/or tungsten.

In a preferred case, the hydrocracking catalyst II comprises a carrier and a hydrogenation metal active component loaded on the carrier, wherein the carrier consists of alumina and a molecular sieve; the molecular sieve is one or more of a Y-type molecular sieve or a beta-type molecular sieve; the hydrogenation metal active component is selected from at least one VIII group metal component and at least one VIB group metal component. Further preferably, the molecular sieve is a Y-type molecular sieve.

More preferably, the hydrocracking catalyst II comprises, in terms of oxides based on the entire hydrocracking catalyst II: 30-72 wt% of aluminum oxide, 1-30 wt% of molecular sieve, 15-35 wt% of VIB group metal component, 2-8 wt% of VIII group metal component, wherein the VIII group metal component is cobalt and/or nickel, and the VIB group metal component is molybdenum and/or tungsten.

The invention also provides a hydrogenation system for the industrial chemical material produced by the hydrogenation method, which comprises a first hydrogenation reaction zone, a second hydrogenation reaction zone, a first high-pressure separator, a second high-pressure separator and a fractionation zone;

a wax oil fraction feeding pipeline and a feeding pipeline rich in aromatic diesel oil fraction are communicated with a hydrogen feeding pipeline and an inlet of a first hydrogenation reaction zone, a hydrofining catalyst is filled at the upstream in the first hydrogenation reaction zone, a hydrocracking catalyst I is filled at the downstream, and an outlet pipeline of the first hydrogenation reaction zone is communicated with an inlet of a first high-pressure separator;

the first high-pressure separator is provided with a liquid phase outlet and a gas phase outlet, the liquid phase outlet is communicated with the first liquid phase material flow discharging pipeline, and the gas phase outlet is communicated with the first gas phase material flow discharging pipeline;

the first gas phase material flow discharging pipeline is communicated with an inlet of a second hydrogenation reaction zone, the second hydrogenation reaction zone is filled with a hydrocracking catalyst II, and an outlet pipeline of the second hydrogenation reaction zone is communicated with an inlet of a second high-pressure separator;

the first liquid phase material flow discharging pipeline is communicated with an inlet of the second high-pressure separator;

the liquid phase outlet of the second high-pressure separator is communicated with the inlet of the fractionating zone through a pipeline, the fractionating zone is provided with a light naphtha fraction outlet, a heavy naphtha fraction outlet, a diesel fraction outlet and a tail oil fraction outlet, and is communicated with corresponding discharge pipelines, wherein the diesel fraction discharge pipeline is communicated with the inlet of the second hydrogenation reaction zone.

In a preferred embodiment, the first liquid phase stream discharging pipeline is divided into two paths, one path of pipeline is communicated with the inlet of the first hydrogenation reaction zone, and the other path of pipeline is communicated with the inlet of the second high-pressure separator.

In a preferred embodiment, the second high-pressure separator is provided with a gas phase outlet and a liquid phase outlet, the gas phase outlet is communicated with the recycle hydrogen purification system through a pipeline, the recycle hydrogen outlet of the recycle hydrogen purification system is communicated with the inlet of the recycle hydrogen compressor, and the outlet of the recycle hydrogen compressor is communicated with the inlet of the first hydrogenation reaction zone.

The invention has the characteristics that:

the hydrocracking catalyst I preferably is amorphous silica-alumina hydrocracking catalyst, and has the characteristics of nitrogen resistance, low cracking activity and improvement on heavy fraction hydrocarbon composition. The hydrofining catalyst and the hydrocracking catalyst I are filled in the first hydrogenation reaction zone in a grading manner, the purposes of desulfurizing and denitrifying the mixed raw materials and improving the quality of the hydrogenated wax oil fraction can be realized under a mild condition, the yield of the obtained hydrogenated wax oil fraction is high, and the hydrogenated wax oil fraction has the characteristic of high hydrogen content, is suitable for being used as a raw material for producing low-carbon olefins and is a high-quality chemical material.

The invention adopts a high-pressure separator for separation, and effectively separates the hydrogenated diesel oil fraction and the hydrogenated wax oil fraction which have larger difference between the distillation range and the hydrocarbon composition. The distillation range is lighter, and the hydrogenated diesel oil fraction rich in the ring structure is in contact with a hydrocracking catalyst II containing a molecular sieve in a second hydrogenation reaction zone to react, and is converted into heavy naphtha fraction with high aromatic hydrocarbon potential content in an ammonia-rich environment at high selectivity. The further preferable hydrocracking catalyst II contains a Y-type molecular sieve, and can reserve the annular structure in the feed to the maximum extent, so that the heavy naphtha fraction in the product has high potential content of aromatic hydrocarbon, and is a high-quality catalytic reforming raw material.

The method and the system provided by the invention can treat catalytic cracking diesel oil in large proportion, produce high-quality catalytic reforming raw materials by utilizing the characteristic of rich aromatic hydrocarbon, and carry out catalytic reforming to obtain aromatic hydrocarbon products and hydrogen as a byproduct, thereby providing cheap hydrogen for refineries to reduce production cost and providing a foundation for refineries to go through aromatic hydrocarbon routes. In addition, the tail oil fraction obtained by the method has high hydrogen content, and is a high-quality raw material for preparing low-carbon olefin. The product of the invention does not contain middle distillate oil, can produce chemical materials to the maximum extent, can promote the development of refineries mainly using fuel oil to an oiling combination type, and improves the economic benefit of enterprises.

Drawings

FIG. 1 is a schematic flow chart of a hydrogenation method for producing industrial materials.

Detailed Description

The method provided by the present invention will be further described with reference to the accompanying drawings, but the invention is not limited thereto. Many devices such as pumps, heat exchangers, compressors, etc. have been omitted from the figure, but are well known to those skilled in the art.

As shown in fig. 1, the mixed raw material rich in the aromatic diesel fraction and the wax oil fraction from the pipeline 1 and the hydrogen-rich gas from the pipeline 25 are mixed and enter the first hydrogenation reaction zone 2, and sequentially contact with the hydrofining catalyst and the hydrocracking catalyst I to perform hydrodesulfurization, hydrodenitrogenation, aromatic hydrogenation saturation reaction and mild hydrocracking reaction. The reaction effluent of the first hydrogenation reaction zone 2 enters a first high-pressure separator 4 through a pipeline 3 for flash separation, and a first gas phase material flow and a first liquid phase material flow are obtained through separation. The first liquid phase stream is extracted by a pipeline 5 and divided into two paths, one path is recycled to the first hydrotreating reaction zone 2 by a pipeline 7, and the other path enters a second high-pressure separator 11 by a pipeline 6. The first gas phase material flows through a pipeline 8 and enters a second hydrogenation reaction zone 9 to contact with a hydrocracking catalyst II for reaction, the hydrogenated diesel oil fraction is hydrocracked into light products such as naphtha, and the reaction effluent of the second hydrogenation reaction zone 9 enters a second high-pressure separator 11 through a pipeline 10 for gas-liquid separation. The sour water separated in the second high pressure separator 11 is withdrawn via line 13. The second gas phase material flow obtained by the separation of the second high pressure separator 11 is hydrogen-rich gas, enters a recycle hydrogen compressor 23 through a pipeline 22, is mixed with new hydrogen from a pipeline 24 after being pressurized, and is sent to the inlet of the first hydrogenation reaction zone 2 through a pipeline 25. The second liquid-phase substance obtained from the second high-pressure separator 11 flows through a pipeline 12 and enters a low-pressure separator 14 for further gas-liquid separation, the low-component gas obtained by separation exits the device through a pipeline 15, and the obtained liquid product enters a fractionating tower 17 through a pipeline 16 for component separation. The light naphtha fraction obtained by separation is pumped out through a pipeline 18; the heavy naphtha fraction obtained by separation is withdrawn through line 19; the diesel oil fraction obtained by separation is pumped out through a pipeline 20 and returned to the inlet of the second hydrogenation reaction zone for recycling; the tail oil fraction obtained by the separation is withdrawn via line 21.

The following examples further illustrate the invention but are not intended to limit the invention thereto.

In the examples and comparative examples, the commercial designation of the hydrorefining catalyst A was RN-410, and the commercial designation of the hydrorefining catalyst B was RS-2000. Hydrocracking catalyst C, sold under the trade designation RHC-140, is a hydrocracking catalyst containing amorphous silica-alumina. The hydrocracking catalyst D has a commercial designation of RHC-5 and is a hydrocracking catalyst containing a molecular sieve. The above catalyst is produced by catalyst Changjingtie of petrochemical Co., Ltd.

The feedstock E and feedstock F used in the examples were obtained from a catalytic cracker, and the feedstock G was vacuum-cracked wax oil, and the properties thereof are shown in Table 1. As can be seen from Table 1, the total aromatic content of the catalytic diesel feedstocks E and F is up to 78 mass%, the aromatic content of the bicyclic hydrocarbons is up to 56 mass%, the cetane number is not higher than 20, and both feedstocks are poor aromatic-rich diesel fractions with high aromatic content; the density of the vacuum wax oil G is 0.9347G/cm³The nitrogen mass fraction is 1800 mu g/g, which is a poor vacuum wax oil fraction.

Example 1

The mixed raw material of raw oil E and raw oil G enters a first hydrogenation reaction zone together with hydrogen, and sequentially contacts and reacts with a hydrofining catalyst A and a hydrocracking catalyst C, the reaction effluent enters a first high-pressure separator for gas-liquid separation, part of the first liquid phase material flow is recycled to the first hydrogenation reaction zone, the mixed raw material is used as a fresh raw material, the recycled first liquid phase material flow is 10 wt% of the fresh raw material, and the rest part of the first liquid phase material flow enters a second high-pressure separator. And the separated first gas phase material flow enters a second hydrogenation reaction zone filled with a hydrocracking catalyst D, the reaction effluent enters a second high-pressure separator for gas-liquid separation, the separated second liquid phase material flow enters a fractionating tower for fractionating to obtain a light naphtha fraction, a heavy naphtha fraction, a diesel oil fraction and a tail oil fraction, the diesel oil fraction returns to the second hydrogenation reaction zone for cyclic conversion, and the circulated diesel oil fraction is 7 wt% of the fresh raw material in the second hydrogenation reaction zone. The reaction conditions are shown in Table 2, and the product yields and properties are shown in Table 3.

Comparative example 1

Under the conventional single-stage series-connection one-pass process, a mixed raw material of raw oil E and raw oil G is mixed with hydrogen and enters a reaction zone, and sequentially passes through a hydrofining reactor and a hydrocracking reactor, wherein the hydrofining reactor is filled with a hydrofining catalyst A, and the hydrocracking reactor is filled with a hydrocracking catalyst D. And carrying out gas-liquid separation and liquid-phase fractionation on the reaction effluent of the hydrocracking reactor to obtain a light naphtha fraction, a heavy naphtha fraction, a diesel fraction and a tail oil fraction. The resulting diesel fraction and part of the tail oil fraction were recycled back to the hydrocracking reactor as cycle oil, which was 17 wt% of the fresh mixed feedstock. The reaction conditions are shown in Table 2, and the product yields and properties are shown in Table 3.

Example 2

The mixed raw material of raw oil F and raw oil G enters a first hydrogenation reaction zone together with hydrogen, and sequentially contacts and reacts with a hydrofining catalyst B and a hydrocracking catalyst C, the reaction effluent enters a first high-pressure separator for gas-liquid separation, and all the separated first liquid-phase material flows enter a second high-pressure separator. And the separated first gas phase material flow enters a second hydrogenation reaction zone filled with a hydrocracking catalyst D, the reaction effluent enters a second high-pressure separator for gas-liquid separation, the separated second liquid phase material flow enters a fractionating tower for fractionating to obtain a light naphtha fraction, a heavy naphtha fraction, a diesel oil fraction and a tail oil fraction, the diesel oil fraction returns to the second hydrogenation reaction zone for cyclic conversion, and the circulated diesel oil fraction is 13 wt% of the fresh raw material in the second hydrogenation reaction zone. The reaction conditions are shown in Table 2, and the product yields and properties are shown in Table 3.

It can be seen from the examples and comparative examples that the method provided by the invention can be used for processing the catalytic diesel oil and wax oil mixed raw material, and obtaining heavy naphtha fraction and tail oil fraction with low hydrogen consumption and high yield, wherein the heavy naphtha fraction has higher potential aromatic hydrocarbon content, and the tail oil fraction has the characteristics of high yield and high hydrogen content, and diesel oil is not produced. The comparative example has high chemical hydrogen consumption, low heavy naphtha yield and low potential content of aromatic hydrocarbon.

TABLE 1

Raw oil	E	F	G
				Density (20 ℃ C.), g/cm³	0.9432	0.9576	0.9347
Sulfur content%	0.15	0.26	0.35
				Nitrogen,. mu.g/g	700	1300	1800
Hydrogen%	9.9	9.7	12.16
				Cetane number	19.3	17.4	/
Composition of hydrocarbons,% by mass
				Alkane hydrocarbons	9.8	13.6	7.8
Cycloalkanes	6.2	8.3	56.3
				Total aromatic hydrocarbons	84.0	78.1	35.9
Aromatic content over bicyclo ring	60.5	56.5	21.4
				Distillation range (ASTM D-86), deg.C			ASTM D-1160
Initial boiling point	195	207	314
				10％	226	235	388
30％	255	266	431
				50％	270	290	453
70％	298	322	466
				90％	331	349	500
End point of distillation	343	366	514

TABLE 2

TABLE 3

Claims

1. A hydrogenation method for producing chemical materials comprises the steps that a mixed raw material rich in aromatic hydrocarbon diesel oil fractions and wax oil fractions enters a first hydrogenation reaction zone and sequentially contacts with a hydrofining catalyst and a hydrocracking catalyst I to react, reaction effluent of the first hydrogenation reaction zone enters a first high-pressure separator to be separated, a first gas-phase material flow obtained through separation enters a second hydrogenation reaction zone and contacts with a hydrocracking catalyst II to react, the first liquid-phase material flow obtained through separation by the first high-pressure separator and reaction effluent of the second hydrogenation reaction zone sequentially enter a second high-pressure separator and a fractionation zone, light naphtha fractions, heavy naphtha fractions, diesel oil fractions and tail oil fractions are obtained through separation, the obtained diesel oil fractions are recycled to the second hydrogenation reaction zone, and the temperature of the first high-pressure separator is 300-370 ℃;

the hydrocracking catalyst I comprises a carrier and a hydrogenation metal active component loaded on the carrier, wherein the carrier consists of alumina and amorphous silica-alumina; the hydrogenation metal active component is selected from at least one VIII group metal component and at least one VIB group metal component;

the hydrocracking catalyst II comprises a carrier and a hydrogenation metal active component loaded on the carrier, wherein the carrier consists of alumina and a molecular sieve; the molecular sieve is one or more of a Y-type molecular sieve or a beta-type molecular sieve; the hydrogenation metal active component is selected from at least one VIII group metal component and at least one VIB group metal component.

2. The method according to claim 1, wherein the mass fraction of the aromatic-rich diesel fraction is 30-80% based on the whole mixed raw material;

the density of the fraction rich in aromatic diesel oil is 0.90g/cm³～0.99g/cm³The distillation range is 165-400 ℃, and the aromatic hydrocarbon content is at least 60 wt%.

3. The process of claim 1 wherein the aromatic-rich diesel fraction is catalytic cracking diesel.

4. The method of claim 1, wherein the wax is a waxThe oil fraction is selected from one or more of vacuum wax oil, coker wax oil, and deasphalted oil, and has a density of 0.88g/cm³～0.97g/cm³The distillation range is 300-600 ℃.

5. The process of claim 1, wherein the temperature of the first high pressure separator is 320 to 350 ℃.

6. The method according to claim 1, wherein the first liquid phase material flow obtained by the separation of the first high-pressure separator is divided into two paths, one path is recycled to the first hydrogenation reaction zone, the other path enters the second high-pressure separator, and the recycled first liquid phase material flow accounts for 1-80% of the mixed raw material by mass.

7. The process according to claim 6, wherein when the hydrogen content of the tail oil fraction is 13.5 wt.% or less, at least a part of the first liquid-phase stream is recycled to the first hydrogenation reaction zone, and the recycled first liquid-phase stream is 1 to 50% by mass of the mixed feedstock.

8. The process of claim 1 wherein the reaction conditions in the first hydrogenation reaction zone are: the hydrogen partial pressure is 6.0-20.0 MPa, the reaction temperature is 300-450 ℃, and the volume ratio of hydrogen to oil is 400-2000 Nm³/m³Taking the mixed raw material as a fresh raw material, wherein the liquid hourly space velocity is 0.2-3.0 h based on the fresh raw material^-1。

9. The process of claim 1 wherein the second hydrogenation zone is operated under the reaction conditions: the hydrogen partial pressure is 6.0-20.0 MPa, the reaction temperature is 300-420 ℃, and the volume ratio of hydrogen to oil is 300-1200 Nm³/m³The liquid hourly space velocity is 0.5-8.0 h^-1。

10. The process of claim 1, wherein the first hydrogenation zone is loaded with a hydrofinishing catalyst upstream, the second hydrogenation zone is loaded with a hydrocracking catalyst I downstream, and the second hydrogenation zone is loaded with a hydrocracking catalyst II; the volume ratio of the hydrocracking catalyst I to the hydrocracking catalyst II is 2: 1-1: 5; the volume ratio of the hydrorefining catalyst to the volume ratio of the hydrocracking catalyst I to the hydrocracking catalyst II is 5: 1-1: 10.

11. The process according to claim 1 or 10, characterized in that the hydrofinishing catalyst is a catalyst of at least one group VIII metal component and at least one group VIB metal component supported on a carrier.

12. The process of claim 11, wherein the hydrofinishing catalyst comprises, on an oxide basis and based on the hydrofinishing catalyst, from 1 to 10 wt.% of the group VIII metal component and from 10 to 45 wt.% of the group VIB metal component; the VIII group metal component is cobalt and/or nickel, and the VIB group metal component is molybdenum and/or tungsten.

13. The process as claimed in claim 1, wherein the hydrocracking catalyst I has the composition, calculated as oxides, based on the hydrocracking catalyst I as a whole: 20 to 70 weight percent of alumina, 20 to 70 weight percent of amorphous alumina-silicon oxide, 10 to 35 weight percent of VIB group metal component and 1 to 15 weight percent of VIII group metal; the VIII group metal component is cobalt and/or nickel, and the VIB group metal component is molybdenum and/or tungsten.

14. The process as claimed in claim 1, wherein the hydrocracking catalyst II has the composition, calculated as oxides, based on the hydrocracking catalyst II as a whole: 30-72 wt% of aluminum oxide, 1-30 wt% of molecular sieve, 15-35 wt% of VIB group metal component, 2-8 wt% of VIII group metal component, wherein the VIII group metal component is cobalt and/or nickel, and the VIB group metal component is molybdenum and/or tungsten.

15. The process of claim 1, wherein the temperature of the second high pressure separator is 150 to 300 ℃.

16. The process of claim 1, wherein the temperature of the second high pressure separator is 220 to 260 ℃.

17. The process of claim 16 wherein the second high pressure separator separates a second vapor stream from a second liquid stream, the second vapor stream being removed of hydrogen sulfide and ammonia and recycled to the first hydrogenation zone as recycle hydrogen, and the second liquid stream being fractionated in a fractionation zone.

18. A hydrogenation system for producing chemical materials comprises a first hydrogenation reaction zone, a second hydrogenation reaction zone, a first high-pressure separator, a second high-pressure separator and a fractionation zone;

19. The system of claim 18, wherein the first liquid stream outlet line is divided into two lines, one line communicating with the inlet of the first hydrogenation reaction zone and the other line communicating with the inlet of the second high pressure separator.

20. The system of claim 18, wherein the second high pressure separator is provided with a vapor phase outlet and a liquid phase outlet, the vapor phase outlet being in communication with the recycle hydrogen purification system via a pipeline, the recycle hydrogen outlet of the recycle hydrogen purification system being in communication with the recycle hydrogen compressor inlet, the recycle hydrogen compressor outlet being in communication with the inlet of the first hydrogenation reaction zone.