CN113930256B

CN113930256B - Hydrocracking method for producing chemical raw material from high-nitrogen crude oil

Info

Publication number: CN113930256B
Application number: CN202010610738.5A
Authority: CN
Inventors: 莫昌艺; 李善清; 孟勇新; 赵广乐; 赵阳; 胡志海
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: 2020-06-29
Filing date: 2020-06-29
Publication date: 2023-06-09
Anticipated expiration: 2040-06-29
Also published as: CN113930256A

Abstract

A hydrocracking method for preparing chemical raw materials from high-nitrogen crude oil includes such steps as heating high-nitrogen crude oil, pretreating, hydrogenating, refining and hydrocracking to obtain the resultant, gas-liquid separation, fractionating in fractionating tower to obtain liquefied gas, naphtha fraction, light catalytic cracking raw material and heavy catalytic cracking raw material. The method can realize direct production of high-quality chemical raw materials from crude oil.

Description

Hydrocracking method for producing chemical raw material from high-nitrogen crude oil

Technical Field

The invention belongs to a method for producing chemical raw materials by processing high-nitrogen crude oil in the presence of hydrogen.

Background

In recent years, the consumption demands of the automotive fuel gasoline and diesel oil in China are slowed down year by year, the market demands of the automotive fuel oil are further reduced in the future under the influence of the development of new energy automobiles using hydrogen energy and electric energy, and meanwhile, the social consumption upgrading is brought to the development of national economy, so that the consumption demands of olefins and aromatic hydrocarbons which can be used as synthetic monomers of various materials are continuously increased.

When the current refineries are classified into fuel oil type, fuel oil-chemical type and full chemical type refineries according to the ratio of fuel oil products and chemical products, and the transition from the fuel oil type refineries to the full chemical type refineries is made, the ratio of chemical products in the structure of the refinery products is gradually increased. In order to meet the market demands of future fuel oil and chemical products, a traditional fuel oil refinery with a certain proportion is transformed into the chemical refinery, however, under the crude oil processing flow of the existing fuel oil refinery, crude oil is generally cut and fractionated into a plurality of narrow fractions and then is processed and produced into fuel oil respectively, and the problem that the proportion of the crude oil converted into chemical raw materials is insufficient is brought, so that the yield of chemical products in a product structure is lower; on the other hand, in the chemical transformation process of the device for producing fuel oil, the risk that the investment cost for device transformation is high or qualified chemical raw materials cannot be produced after transformation exists.

CN101760235a discloses a method for hydrocracking heavy crude oil, in which heavy crude oil with API degree less than 20 is sequentially subjected to hydrogenation protective agent, hydrodemetallization agent, hydrodesulphurization agent I, hydrocracking agent and hydrodesulphurization agent II in the presence of hydrogen, and then the hydrogenated crude oil with increased API degree and reduced viscosity is obtained through separation, however, by adopting the method of the invention, hydrogenated crude oil with reduced mass fractions of impurities such as metal, sulfur, nitrogen and the like can be obtained, but the requirement of qualified chemical raw materials with production property cannot be met.

CN105358661a and CN109593556a disclose a process and a plant for converting crude oil into petrochemicals with improved propylene yields. The method comprises the steps of firstly, distilling crude oil to generate gas, kerosene and/or gas oil and residual oil, and on the one hand, upgrading the residual oil to generate LPG and modified effluent; on the other hand, the upgraded effluent undergoes at least 50% aromatic ring opening with kerosene and gas oil to produce petrochemicals.

CN104093821B discloses a hydrotreating and steam pyrolysis process including hydrogen redistribution and integration for direct processing of crude oil. The process first separates crude oil into light components and heavy components, wherein the heavy components are hydrogenated to produce an effluent having reduced contaminant content, reduced paraffin content, and reduced BMCI value, and the heavy fraction hydrogenated effluent and light components are passed to a steam pyrolysis zone to produce olefins and aromatics chemicals.

CN106103664a discloses an integrated hydrocracking process. The method comprises the steps of carrying out hydrotreatment on crude oil and raw materials from coking in a first hydrogenation reaction zone to obtain a stream which is separated into LPG and a liquid-phase stream, enabling the liquid-phase stream to enter a second hydrocracking zone for reaction to generate a BTXE stream, and carrying out thermal cracking on the residual liquid stream to generate a coking liquid product and petroleum coke.

Disclosure of Invention

In order to solve the problems of long process flow, low yield and poor properties of chemical raw materials in crude oil production in the prior art, the invention provides a hydrocracking method for directly producing a reforming material and a catalytic cracking raw material from high-nitrogen crude oil.

The invention provides a hydrocracking method for producing chemical raw materials from high-nitrogen crude oil, which comprises the steps of arranging a pretreatment unit and a hydrocracking unit, wherein the pretreatment unit is provided with a pretreatment reaction zone and a hydrotreating reaction zone, and the hydrocracking unit is provided with a hydrofining reaction zone and a hydrocracking reaction zone; heating a high-nitrogen crude oil raw material, sequentially passing through a pretreatment reaction zone, a hydrotreating reaction zone, a hydrofining reaction zone and a hydrocracking reaction zone in the presence of hydrogen to obtain a reaction effluent, separating gas from liquid, then entering a fractionating tower, and fractionating to obtain liquefied gas, naphtha fraction, light catalytic cracking raw material and heavy catalytic cracking raw material, wherein:

(1) The pretreatment reaction zone is graded filled with a hydrogenation protective agent and a hydrodemetallization agent, the demetallization rate of the pretreatment reaction zone is controlled to be not less than 90%, and the deasphalting rate is controlled to be not less than 90%;

(2) The hydrotreating reaction zone is filled with a first hydrofining catalyst, the hydrogenation depth of the hydrotreating reaction zone is controlled, and the mass fraction of organic nitriding substances in a liquid phase stream obtained by separating reaction effluent is 100-600 mug/g;

(3) The hydrofining reaction zone is filled with a second hydrofining catalyst, and the conversion depth of the hydrofining reaction zone is controlled to be not more than 20% of aromatic hydrocarbon mass fraction in fraction with the temperature of more than 350 ℃ in hydrofining generated oil;

(4) The hydrocracking reaction zone is filled with a hydrocracking catalyst, and the conversion depth of the hydrocracking reaction zone is controlled to be more than 350 ℃ and the conversion rate of the fraction is controlled to be 10% -50%.

In the invention, the crude oil raw material is one crude oil or is obtained by mixing a plurality of crude oils, and the source of the crude oil is not limited. Preferably, the crude oil feedstock has an API grade of 27 or less and a nitrogen content of 2500 μg/g to 8000 μg/g.

Further preferably, the crude oil raw material contains Fe not more than 40 mug/g, ca not more than 40 mug/g, ni not more than 20 mug/g, V not more than 20 mug/g, carbon residue mass fraction not more than 15%, asphaltene not more than 5000 mug/g.

The high nitrogen crude oil raw material is sequentially mixed with a hydrogenation protective agent and a hydrogenation catalyst in a pretreatment reaction zoneHydrodemetallization agent contact performs hydrodemetallization, hydrodeasphaltene reactions, and in preferred cases, the reaction conditions of the pretreatment reaction zone: the reaction pressure is 6.0 MPa-20.0 MPa, the reaction temperature is 260-420 ℃, and the liquid hourly space velocity is 0.5h ^-1 ～15h ^-1 The volume ratio of hydrogen to oil is 300-2000.

In a preferred case, the hydrogenation protecting agent comprises a carrier and an active metal component, wherein the carrier is alumina, the active metal component is selected from at least one VIII group metal and at least one VIB group metal, the VIII group metal is selected from nickel and/or cobalt, the VIB group metal is selected from molybdenum and/or tungsten, the content of the VIII group metal is 0.3-5 wt% based on the total weight of the hydrogenation protecting agent, and the content of the VIB group metal is 1-10 wt% based on oxide.

In a preferred embodiment of the present invention, at least two or more kinds of hydrogenation protecting agents are filled in the pretreatment reaction zone, the particle size of the hydrogenation protecting agent becomes smaller gradually and the mass fraction of the active metal component becomes larger gradually along the direction of the flow of the reactants.

In a preferred case, the hydrodemetallization agent comprises a carrier and an active metal component, the carrier is alumina, the active metal component is selected from at least one group VIII metal and at least one group VIB metal, the group VIII metal is selected from nickel and/or cobalt, the group VIB metal is selected from molybdenum and/or tungsten, the content of the group VIII metal is 1 wt% to 5 wt% based on the total weight of the hydrodemetallization agent, and the content of the group VIB metal is 1 wt% to 15 wt% based on the oxide.

In a preferred embodiment of the present invention, the pretreatment reaction zone is filled with at least two or more hydrodemetallization agents, the particle size of which becomes smaller and the mass fraction of the active metal component becomes larger in the direction of the reactant flow.

In the invention, the reaction effluent of the pretreatment reaction zone directly enters the hydrogenation reaction zone without separation, contacts with a first hydrofining catalyst and carries out hydrodesulfurization and hydrodenitrogenation reaction, and in the invention, the mass fraction of organic nitriding substances in a liquid phase stream obtained by separating the reaction effluent of the hydrogenation reaction zone is controlled to be 100-600 mug/g.

In preferred cases, the reaction conditions of the hydrotreating reaction zone: the reaction pressure is 6.0 MPa-20.0 MPa, the reaction temperature is 280-400 ℃, and the liquid hourly space velocity is 0.5h ^-1 ～6h ^-1 The volume ratio of hydrogen to oil is 300-2000.

In a preferred case, the first hydrofinishing catalyst is at least one catalyst selected from group VIB metals, or at least one catalyst selected from group VIII metals, or combinations thereof, supported on an alumina or/and alumina-silica carrier; the VIII metal is selected from nickel and/or cobalt, the VIB metal is selected from molybdenum and/or tungsten, the content of the VIII metal is 1-15 wt% based on the total weight of the first hydrofining catalyst, and the content of the VIB metal is 5-40 wt% based on oxide.

In a preferred embodiment of the invention, the reaction effluent of the pretreatment unit is subjected to gas-liquid separation in a separation system to obtain a hydrogen-rich gas and a liquid stream. The obtained liquid phase material flow enters a hydrocracking unit; the hydrogen-rich gas is obtained to remove H ₂ S and NH ₃ The catalyst can be recycled to the pretreatment unit or the hydrocracking unit. The separation system is selected from one or a combination of a plurality of high-pressure stripping towers, hot high-pressure flash separators, cold high-pressure flash separators, hot low-pressure flash separators and cold low-pressure flash separators.

In a preferred embodiment, the liquid stream from the pretreatment unit is passed to a hydrofinishing reaction zone and contacted with a second hydrofinishing catalyst in the presence of hydrogen to effect hydrodesulfurization, hydrodenitrogenation, partial saturation of aromatics, and the like. Reaction conditions in the hydrofining reaction zone: the reaction pressure is 6.0 MPa-20.0 MPa, the reaction temperature is 280-400 ℃, and the liquid hourly space velocity is 0.5h ^-1 ～6h ^-1 The volume ratio of hydrogen to oil is 300-2000.

In order to obtain high-quality chemical raw materials, the conversion depth of the hydrofining reaction zone is controlled, and in a preferred case, the conversion depth of the hydrofining reaction zone is controlled to be not more than 16% of the mass fraction of aromatic hydrocarbon in the fraction with the temperature of 350 ℃ in hydrofining generated oil.

In a preferred case, the second hydrofinishing catalyst is at least one catalyst selected from group VIB metals, or at least one selected from group VIII metals, or a combination thereof, supported on an alumina or/and alumina-silica support. Wherein the VIII group metal is selected from nickel and/or cobalt, the VIB group metal is selected from molybdenum and/or tungsten, the content of the nickel and/or cobalt is 1-15 wt% based on the total weight of the second hydrofining catalyst, and the content of the molybdenum and/or tungsten is 5-40 wt% based on the total weight of the second hydrofining catalyst.

In the present invention, the first hydrofining catalyst and the second hydrofining catalyst may be the same or different. It is preferred that the hydrodenitrogenation performance of the first hydrofinishing catalyst is superior to the hydrodenitrogenation performance of the second hydrofinishing catalyst.

In the present invention, a gas-liquid separation device may be provided or may be omitted between the hydrofining reaction zone and the hydrocracking reaction zone. When the gas-liquid separation equipment is not arranged, the reaction effluent of the hydrofining reaction zone enters the hydrocracking reaction zone together, and the liquid phase material of the reaction effluent of the hydrofining reaction zone is hydrofined oil. When the gas-liquid separation equipment is arranged, the hydrogen-rich gas and the hydrofining generated oil are obtained after the gas-liquid separation of the hydrofining reaction effluent. The hydrofining generated oil enters a hydrocracking reaction zone to contact with a hydrocracking catalyst for a hydrocracking reaction.

In preferred cases, the hydrocracking reaction zone reaction conditions: the reaction pressure is 6.0 MPa-20.0 MPa, the reaction temperature is 290-420 ℃, and the liquid hourly space velocity is 0.3h ^-1 ～5h ^-1 The volume ratio of hydrogen to oil is 300-2000;

in order to obtain high-quality chemical raw materials, the conversion depth of the hydrocracking reaction zone is controlled to be 10-50% of the conversion rate of the fraction at the temperature of 350 ℃.

In the present invention, the conversion rate of the fraction at >350 ℃ is as follows: 100 (fraction mass fraction of >350 ℃ in feedstock-fraction mass fraction of >350 ℃ in hydrocracked oils)/fraction mass fraction of >350 ℃ in feedstock

In a preferred case, the hydrocracking catalyst comprises a carrier and an active metal component supported on the carrier, the carrier consisting of a refractory inorganic oxide and a Y-type molecular sieve; the heat-resistant inorganic oxide is selected from one or more of silicon oxide, aluminum oxide and amorphous aluminum silicate; the active metal component is selected from at least two metal components of VIB group metal and VIII group metal; the hydrocracking catalyst is 15-35 wt% of VIB metal, 2-8 wt% of VIII metal, 3-35 wt% of Y-type molecular sieve and the balance of heat-resistant inorganic oxide.

In a preferred embodiment of the present invention, the hydrocracking reaction zone is filled with the post-hydrofining catalyst at a lower portion thereof, and the filling ratio of the hydrocracking catalyst to the post-hydrofining catalyst is 8:1 to 15:1. according to the material flow direction, the hydrofining generated oil sequentially passes through a hydrocracking catalyst and a post hydrofining catalyst.

In the present invention, the post-hydrofining catalyst packed in the lower portion of the hydrocracking reaction zone may be the same as or different from the first hydrofining catalyst packed in the hydrofining reaction zone.

In a preferred case, the post-hydrofinishing catalyst is a catalyst of at least one group VIB metal, or at least one group VIII metal, or a combination thereof, supported on an alumina or/and alumina-silica support. Further preferably, the group VIII metal is selected from nickel and/or cobalt, the group VIB metal is selected from molybdenum and/or tungsten, the content of nickel and/or cobalt is 1 wt% to 15 wt% on oxide basis, and the content of molybdenum and/or tungsten is 5 wt% to 40 wt%, based on the total weight of the post-hydrofinishing catalyst.

In the invention, hydrogen-rich gas and hydrocracking generated oil are obtained after the hydrocracking reaction effluent is subjected to gas-liquid separation, and the hydrocracking generated oil enters a fractionating tower to be fractionated to obtain chemical raw materials such as liquefied gas, naphtha fraction, light catalytic cracking raw materials, heavy catalytic cracking raw materials and the like. Wherein the cutting point of the naphtha fraction and the light catalytic cracking raw material is 130-160 ℃, preferably 140 ℃; the cutting point of the light catalytic cracking raw material and the heavy catalytic cracking raw material is 330-380 ℃, preferably 350 ℃.

The naphtha fraction obtained by the method has low sulfur and nitrogen impurity content and high aromatic potential content, and is a high-quality reforming raw material.

The catalytic cracking process refers to a process of producing low-carbon olefins such as ethylene, propylene, butylene and the like by high-temperature cracking of petroleum hydrocarbon in the presence of a catalyst and simultaneously producing light aromatic hydrocarbon, and can be specifically one or more of a catalytic cracking process (DCC process), a catalytic pyrolysis process (CPP process), a process of preparing ethylene by directly cracking heavy oil (HCC process) and other catalytic cracking processes, preferably a catalytic cracking DCC process.

The light catalytic cracking raw material and the heavy catalytic cracking raw material obtained by the invention are high-quality raw materials in the catalytic cracking process, and the obtained low-carbon olefin has high yield and high product income. Specifically, the weight fraction of hydrogen in the light catalytic cracking raw material obtained by the invention is not less than 13.5 percent, and the UOP K value of the light catalytic cracking raw material is not less than 12. The mass fraction of hydrogen in the heavy catalytic cracking raw material obtained by the invention is less than or equal to 13.5%.

The inventors of the present invention have found through intensive studies that the higher the hydrogen mass fraction of the catalytic cracking feedstock, the higher the olefin content in the catalytic cracking product. When the mass fraction of hydrogen in the catalytic cracking raw material is controlled to be less than or equal to 13.5%, good catalytic cracking product benefits can be obtained. In addition, the economy of the catalytic cracking device is in positive correlation with the UOP K value of the raw material, the UOP K value of the raw material is generally larger than 11.9, the catalytic cracking (DCC) device can be guaranteed to have better economy, and the yield of ethylene, propylene and butene of the catalytic cracking device is gradually increased along with the increase of the UOP K value of the raw material, so that the economy of the device is gradually improved.

The UOP K value, also called the characteristic factor K, is calculated from the formula

Wherein Tv is the volume average boiling point of the raw material, d _15.6 Is the density of the raw material at 15.6 ℃.

The treatment method provided by the invention is used for producing high-quality chemical raw materials, particularly high-quality light catalytic cracking raw materials in large scale by a hydrocracking method, wherein the light catalytic cracking raw materials meet the requirements that the mass fraction of hydrogen is less than or equal to 13.5%, and the UOP K value is less than or equal to 12. The heavy catalytic cracking raw material obtained by the method meets the mass fraction of hydrogen of less than 13.5 percent, and is also a high-quality catalytic cracking raw material. The high-quality catalytic cracking raw material is adopted, and the catalytic cracking device can achieve the purpose of improving the yield of the high-value products of the low-carbon olefin.

Detailed Description

The following examples further illustrate a process for the hydrocracking of crude oil to produce a substantially upgraded material in accordance with the present invention, but the present invention is not limited thereto.

Comparative example 1-1, example 1-1

The comparative examples and examples are presented to illustrate the effect of the differences in the nature of the light catalytic cracking feedstock on the product yield of the catalytic cracker.

The results of two light catalytic cracking feedstocks in a DCC pilot test apparatus are shown in table 1.

The catalytic cracking catalyst is used with the commodity brand of MMC-2 and is produced by Qilu division of China petrochemical Co.

The reaction conditions of the DCC device were: the reaction temperature is 580 ℃, the agent-oil ratio is 12, and the steam injection amount is 25 weight percent (accounting for the raw materials).

As is clear from the data in Table 1, the two light catalytic cracking raw materials with the same distillation range and different hydrogen content and UOP K value react under the same catalytic cracking process conditions, the mass fraction of hydrogen in the light catalytic cracking raw material 2 is more than 13.5%, and the UOP K value is more than 12, so that the higher yield of the low-carbon olefins (ethylene, propylene and butylene) is obtained.

TABLE 1

In the following examples and comparative examples of the present invention,

the yield of naphtha at 140 ℃ is defined as: the weight percentage of naphtha fraction (< 140 ℃) and raw materials cut by the whole fraction product through a fractionating tower;

the light catalytic cracking raw material yield is defined as follows: the whole fraction product is cut by a fractionating tower to obtain light catalytic cracking raw materials (140-350 ℃) and weight percentage of the raw materials;

the heavy catalytic cracking feedstock yield is defined as: the whole fraction product is obtained by cutting heavy catalytic cracking raw materials (> 350 ℃) through a fractionating tower and the weight percentage of the raw materials.

The crude oil feedstock basic properties used in the examples and comparative examples are listed in Table 2.

The hydrogenation protecting agent, the hydrodemetallization agent, the first hydrofining catalyst, the second hydrofining catalyst, the hydrocracking catalyst and the post hydrofining catalyst adopted in the examples and the comparative examples of the present invention are all produced by China petrochemical catalyst division.

Comparative example 1

Raw material D and hydrogen are mixed and then sequentially pass through a pretreatment reaction zone and a hydrotreatment reaction zone of a pretreatment unit, and obtained reaction effluent is subjected to gas-liquid separation to obtain a gas-phase material flow and a liquid-phase material flow, wherein the organic nitrogen content of the obtained liquid-phase material flow is 600 mug/g; the gas phase material flow is mixed with the liquid phase material flow to enter a hydrocracking unit after hydrogen sulfide and ammonia gas are removed, and the mixture sequentially passes through a hydrofining reaction zone and a hydrocracking reaction zone to react, wherein the mass fraction of aromatic hydrocarbon in fraction with the temperature of more than 350 ℃ in hydrofining generated oil is controlled to be 18%; the conversion depth in the hydrocracking reaction zone was controlled to be >350 ℃ and the conversion of the fraction was 50%. The reaction effluent of the hydrocracking reaction zone is separated to obtain naphtha fraction of <140 ℃, light catalytic cracking raw material fraction of 140-350 ℃ and heavy catalytic cracking raw material fraction of >350 ℃. The process condition parameters and product yields and property data are shown in Table 3.

As can be seen from the data in table 3, the mass fraction of the light catalytic cracking raw material hydrogen obtained from the raw material D under the experimental process conditions is 14.18%, and the UOP K value is 11.2; the mass fraction of the obtained heavy catalytic cracking raw material hydrogen is 13.48%, the UOP K value is 11.9, and the data show that neither the light catalytic cracking raw material nor the heavy catalytic cracking raw material obtained from the raw material E can be used as a high-quality catalytic cracking raw material.

Example 1, example 2 and example 3

The raw materials A, B and C adopted in examples 1, 2 and 3 are respectively mixed with hydrogen and then sequentially pass through a pretreatment reaction zone and a hydrotreatment reaction zone of a pretreatment unit, and the obtained reaction effluent is subjected to gas-liquid separation to obtain a gas-phase material flow and a liquid-phase material flow, wherein the organic nitrogen content of the obtained liquid-phase material flow is 100 mug/g, 300 mug/g and 500 mug/g respectively; the gas phase material flow is mixed with the liquid phase material flow to enter a hydrocracking unit after hydrogen sulfide and ammonia gas are removed, the mixture sequentially passes through a hydrofining reaction zone and a hydrocracking reaction zone to react, the mass fractions of fraction aromatics with the temperature of more than 350 ℃ in hydrofining generated oil are controlled to be 8%, 10% and 13% respectively, the conversion depth of the hydrocracking reaction zone is controlled to be 12%, 36% and 43% respectively, and the reaction effluent of the hydrocracking reaction zone is separated to obtain naphtha fraction with the temperature of less than 140 ℃, light catalytic cracking raw material fraction with the temperature of 140-350 ℃ and heavy catalytic cracking raw material fraction with the temperature of more than 350 ℃. The process condition parameters and product yields and property data are shown in Table 3.

As can be seen from the data in table 3, the hydrogen mass fractions of the light catalytic cracking raw materials obtained under the experimental process conditions of raw materials A, B and C are 14.56%, 14.45% and 14.34%, respectively, and UOP K values are 12.6, 12.5 and 12.3, respectively; the mass fractions of the obtained heavy catalytic cracking raw materials are 14.33%, 14.32% and 14.15%, and the UOP K values are 13.2, 12.7 and 12.6 respectively.

Comparative example 2, comparative example 3 and comparative example 4

Comparative examples 2, 3 and 4 used raw material C, and reacted with hydrogen in turn through a pretreatment reaction zone and a hydrotreating reaction zone, the obtained reaction effluent was separated to obtain a gas phase stream and a liquid phase stream, the organic nitrogen content of the obtained liquid phase stream was 20. Mu.g/g, 50. Mu.g/g and 1200. Mu.g/g, respectively, wherein the gas phase stream was mixed with the liquid phase stream after removal of hydrogen sulfide and ammonia gas, and then reacted in a hydrocracking unit. The mass fractions of the fraction aromatic hydrocarbon at the temperature of more than 350 ℃ in the hydrofining generated oil are respectively 13%, 14% and 16%, the conversion depth of the hydrocracking reaction zone is controlled to be respectively 50%, 40% and 40% of the fraction conversion rate at the temperature of more than 350 ℃, and the reaction effluent of the hydrocracking reaction zone is separated to obtain naphtha fraction at the temperature of less than 140 ℃, light catalytic cracking raw material fraction at the temperature of 140-350 ℃ and heavy catalytic cracking raw material fraction at the temperature of more than 350 ℃. The process condition parameters and product yields and property data are shown in Table 4.

As can be seen from the data in Table 4, the light and heavy catalytic cracking feedstock properties obtained from feedstock C under the experimental process conditions are both good quality catalytic cracking feedstock, but comparative examples 2 and 3 are poor in the hydrocracking unit operation resistance due to the poor temperature sensitivity of the feedstock to the hydrocracking reaction unit due to the low organic nitrogen content in the liquid phase stream entering the hydrocracking unit. On the one hand, the comparative example 4 has the problems that the temperature of the hydrotreating reaction zone is not matched with that of the hydrofining reaction zone, and on the other hand, the operation condition of the hydrocracking unit is severe due to the high organic nitrogen content of the liquid-phase material flow entering the hydrocracking unit, so that the operation period of the hydrocracking unit is shortened.

Example 4

In the embodiment 4, the raw material C is mixed with hydrogen and then sequentially passes through a pretreatment reaction zone and a hydrogenation reaction zone to react, the obtained reaction effluent is separated to obtain a gas-phase material flow and a liquid-phase material flow, the organic nitrogen content of the obtained liquid-phase material flow is 150 mug/g, and the gas-phase material flow is mixed with the liquid-phase material flow after hydrogen sulfide and ammonia are removed and enters a hydrocracking unit to react. Controlling the mass fraction of fraction aromatic hydrocarbon at the temperature of more than 350 ℃ in the hydrofining generated oil to be 15%, controlling the conversion depth of a hydrocracking reaction zone to be 40% of fraction conversion rate at the temperature of more than 350 ℃, and separating reaction effluent of the hydrocracking reaction zone to obtain naphtha fraction at the temperature of less than 140 ℃, light catalytic cracking raw material fraction at the temperature of 140-350 ℃ and heavy catalytic cracking raw material fraction at the temperature of more than 350 ℃. The process condition parameters and product yields and property data are shown in Table 4.

As can be seen from the data in Table 4, the light and heavy catalytic cracking raw materials obtained by the method provided by the invention can be used as high-quality catalytic cracking raw materials, the temperatures of the hydrotreating reaction zone and the hydrofining reaction zone are well matched, the operation condition of the hydrocracking reaction zone is mild, the operation fluctuation resistance of the hydrocracking unit is strong, and the operation period is long.

Example 5, comparative example 5

In the embodiment 5 and the comparative example 5, the raw material B is mixed with hydrogen and then sequentially reacted in a pretreatment reaction zone and a hydrotreating reaction zone, the obtained reaction effluent is separated to obtain a gas-phase stream and a liquid-phase stream, the organic nitrogen content of the obtained liquid-phase stream is 180 mug/g and 185 mug/g respectively, and the gas-phase stream is mixed with the liquid-phase stream after removing hydrogen sulfide and ammonia gas and then enters a hydrocracking unit for reaction. In the example 5, the mass fraction of distillate aromatic hydrocarbon with the temperature of more than 350 ℃ in hydrofining generated oil is controlled to be 15%; the mass fraction of distillate aromatic hydrocarbon in the hydrofining oil generated in comparative example 5 at the temperature of more than 350 ℃ is 23 percent. In example 5 and comparative example 5, the conversion depth of the hydrocracking reaction zone was controlled to be 39% for fraction conversion at >350 ℃, and the reaction effluent of the hydrocracking reaction zone was separated to obtain a naphtha fraction of <140 ℃, a light catalytic cracking feed fraction of 140 ℃ to 350 ℃ and a heavy catalytic cracking feed fraction of >350 ℃. The process condition parameters and product yields and property data are shown in Table 5.

As can be seen from the data in Table 5, the light and heavy catalytic cracking raw materials obtained in example 5 by the method provided by the invention can be used as high-quality catalytic cracking raw materials. However, neither the light nor heavy catalytic cracking feedstock obtained in comparative example 5 was a good quality catalytic cracking feedstock.

Example 6, comparative example 6

In the embodiment 6 and the comparative example 6, the raw material A is mixed with hydrogen and then sequentially reacted in a pretreatment reaction zone and a hydrotreating reaction zone, the obtained reaction effluent is separated to obtain a gas-phase stream and a liquid-phase stream, the organic nitrogen content of the obtained liquid-phase stream is 180 mug/g and 220 mug/g respectively, and the gas-phase stream is mixed with the liquid-phase stream after removing hydrogen sulfide and ammonia gas and then enters a hydrocracking unit for reaction. The mass fraction of distillate aromatics >350 ℃ in the hydrofinished product oil in example 6 and comparative example 6 was 10% and 15%, respectively. The conversion of the hydrocracking reaction zone in example 6 was controlled to be >350 ℃ and the conversion of the fraction was 10%, and the conversion of the hydrocracking reaction zone in comparative example 6 was controlled to be >350 ℃ and the conversion of the fraction was 7%. The reaction effluent of the hydrocracking reaction zone is separated to obtain naphtha fraction of <140 ℃, light catalytic cracking raw material fraction of 140-350 ℃ and heavy catalytic cracking raw material fraction of >350 ℃. The process condition parameters and product yields and property data are shown in Table 6.

As can be seen from the data in Table 6, the light and heavy catalytic cracking raw materials obtained in example 6 by the method provided by the invention can be used as high-quality catalytic cracking raw materials. However, neither the light nor heavy catalytic cracking feedstock obtained in comparative example 6 was a good quality catalytic cracking feedstock.

TABLE 2 crude oil feedstock Properties after desalting

TABLE 3 Table 3

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TABLE 4 Table 4

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TABLE 5

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TABLE 6

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Claims

1. The hydrocracking method for producing the chemical raw material by the high-nitrogen crude oil is characterized by comprising a pretreatment unit and a hydrocracking unit, wherein the pretreatment unit is provided with a pretreatment reaction zone and a hydrotreating reaction zone, and the hydrocracking unit is provided with a hydrofining reaction zone and a hydrocracking reaction zone; heating a high-nitrogen crude oil raw material, sequentially passing through a pretreatment reaction zone, a hydrotreating reaction zone, a hydrofining reaction zone and a hydrocracking reaction zone in the presence of hydrogen to obtain a reaction effluent, separating gas from liquid, then entering a fractionating tower, and fractionating to obtain liquefied gas, naphtha fraction, light catalytic cracking raw material and heavy catalytic cracking raw material, wherein:

(4) The hydrocracking reaction zone is filled with a hydrocracking catalyst, and the conversion depth of the hydrocracking reaction zone is controlled to be more than 350 ℃ and the conversion rate of the fraction is controlled to be 10% -50%;

the API degree of the crude oil raw material is not less than 27, and the nitrogen content is 2500-8000 mu g/g;

the cutting point of the naphtha fraction and the light catalytic cracking raw material is 130-160 ℃; the cutting point of the light catalytic cracking raw material and the heavy catalytic cracking raw material is 330-380 ℃, the hydrogen mass fraction of the light catalytic cracking raw material is not less than 13.5%, and the UOP K value of the light catalytic cracking raw material is not less than 12; the mass fraction of hydrogen in the heavy catalytic cracking raw material is not less than 13.5 percent,

the UOP K value is calculated by a formula

2. The method of claim 1, wherein the crude oil feed contains no more than 40 μg/g of Fe, no more than 40 μg/g of Ca, no more than 20 μg/g of Ni, no more than 20 μg/g of V, no more than 15% of carbon residue mass fraction, and no more than 5000 μg/g of asphaltene.

3. The process of claim 1 wherein the reaction conditions of the pretreatment reaction zone: the reaction pressure is 6.0 MPa-20.0 MPa, the reaction temperature is 260-420 ℃, and the liquid hourly space velocity is 0.5h ^-1 ～15h ^-1 The volume ratio of hydrogen to oil is 300-2000.

4. The process according to claim 1, characterized in that the hydroprotectant comprises a support and an active metal component, the support being alumina, the active metal component being selected from at least one group VIII metal selected from nickel and/or cobalt and at least one group VIB metal selected from molybdenum and/or tungsten, the group VIII metal being present in an amount of 0.3% to 5% by weight, based on the total weight of the hydroprotectant, and the group VIB metal being present in an amount of 1% to 10% by weight, based on the total weight of the hydroprotectant.

5. The method according to claim 1 or 4, wherein at least two or more kinds of hydrogenation protecting agents are charged in the pretreatment reaction zone, the particle size of the hydrogenation protecting agent becomes smaller gradually and the mass fraction of the active metal component becomes larger gradually in the direction of the flow of the reactants.

6. The process according to claim 1, characterized in that the hydrodemetallization agent comprises a support and an active metal component, the support being alumina, the active metal component being selected from at least one group VIII metal selected from nickel and/or cobalt and at least one group VIB metal selected from molybdenum and/or tungsten, the group VIII metal being present in an amount of 1 to 5 wt.% and the group VIB metal being present in an amount of 1 to 15 wt.% based on the total weight of the hydrodemetallization agent, calculated as oxides.

7. The method according to claim 1 or 6, wherein at least two kinds of hydrodemetallization agents are filled in the pretreatment reaction zone, the particle size of the hydrodemetallization agent gradually becomes smaller and the mass fraction of the active metal component gradually increases along the flow direction of the reactants.

8. The process of claim 1 wherein the reaction conditions in the hydrotreating reaction zone: the reaction pressure is 6.0 MPa-20.0 MPa, the reaction temperature is 280-400 ℃, and the liquid hourly space velocity is 0.5h ^-1 ～6h ^-1 The volume ratio of hydrogen to oil is 300-2000.

9. The process according to claim 1, wherein the first hydrofinishing catalyst is a catalyst of at least one group VIB metal, or at least one group VIII metal, or a combination thereof, supported on an alumina or/and alumina-silica support; the VIII metal is selected from nickel and/or cobalt, the VIB metal is selected from molybdenum and/or tungsten, the content of the VIII metal is 1-15 wt% based on the total weight of the first hydrofining catalyst, and the content of the VIB metal is 5-40 wt% based on oxide.

10. The process according to claim 1, wherein the reaction effluent of the pretreatment unit is subjected to gas-liquid separation in a separation system to obtain a hydrogen-rich gas and a liquid stream; the obtained liquid phase material flow enters a hydrocracking unit; the hydrogen-rich gas is obtained to remove H ₂ S and NH ₃ And (3) recycling, namely recycling to a pretreatment unit or recycling to a hydrocracking unit.

11. The process of claim 1 wherein the hydrofinishing reaction zone reaction conditions: the reaction pressure is 6.0 MPa-20.0 MPa, the reaction temperature is 280-400 ℃, and the liquid hourly space velocity is 0.5h ^-1 ～6h ^-1 The volume ratio of hydrogen to oil is 300-2000;

the conversion depth of the hydrofining reaction zone is controlled to be less than 16% by mass fraction of aromatic hydrocarbon in fraction with the temperature of more than 350 ℃ in hydrofining generated oil.

12. The process according to claim 1, wherein the second hydrofinishing catalyst is a catalyst of at least one group VIB metal, or at least one group VIII metal, or a combination thereof, supported on an alumina or/and alumina-silica support; the VIII group metal is selected from nickel and/or cobalt, the VIB group metal is selected from molybdenum and/or tungsten, the content of the VIII group metal is 1-15 wt% based on the total weight of the second hydrofining catalyst, and the content of the VIB group metal is 5-40 wt% based on oxide.

13. The process of claim 1 wherein the hydrocracking reaction zone reaction conditions: the reaction pressure is 6.0 MPa-20.0 MPa, the reaction temperature is 290-420 ℃, and the liquid hourly space velocity is 0.3h ^-1 ～5h ^-1 The volume ratio of hydrogen to oil is 300-2000.

14. The process of claim 1 wherein the hydrocracking catalyst comprises a support and an active metal component supported on the support, the support consisting of a refractory inorganic oxide and a Y-type molecular sieve; the heat-resistant inorganic oxide is selected from one or more of silicon oxide, aluminum oxide and amorphous aluminum silicate; the active metal component is selected from at least two metal components of VIB group metal and VIII group metal; the hydrocracking catalyst is 15-35 wt% of VIB metal, 2-8 wt% of VIII metal, 3-35 wt% of Y-type molecular sieve and the balance of heat-resistant inorganic oxide.

15. The process of claim 1 wherein the post-hydrofinishing catalyst is packed in the lower portion of the hydrocracking reaction zone in a loading ratio of 8:1 to 15:1.