CN113930255B - Hydrogenation method for producing chemical raw materials from crude oil - Google Patents

Abstract

A hydrogenation method for producing chemical raw materials from crude oil. Crude raw materials sequentially pass through the first pretreatment reaction zone, the second pretreatment reaction zone, the hydrofining reaction zone and the hydrocracking reaction zone to obtain the reaction effluent after gas-liquid separation It enters the fractionation tower and fractionates to obtain liquefied gas, naphtha fraction, light catalytic cracking raw materials, and heavy catalytic cracking raw materials. By adopting the method of the invention, the direct production of high-quality chemical raw materials from crude oil can be realized.

Description

A method for hydrogenating crude oil to produce chemical raw materials

Technical Field

The invention belongs to a method for processing crude oil to produce chemical raw materials in the presence of hydrogen.

Background Art

In recent years, the consumption demand for automotive fuel gasoline and diesel in my country has slowed down year by year. In the future, affected by the development of new energy vehicles based on hydrogen and electric energy, the market demand for automotive fuel oil will further decrease. At the same time, the development of the national economy has brought about social consumption upgrades, and the consumption demand for olefins and aromatics, which can be used as monomers for the synthesis of various materials, continues to grow.

Generally, according to the ratio of fuel oil products and chemical products, current refineries can be divided into fuel oil type, fuel oil-chemical type and full chemical type refineries. When the fuel oil type refinery is transformed into a full chemical type refinery, the proportion of chemical products in the refinery product structure gradually increases. In order to meet the market demand for fuel oil and chemical products in the future, there will be a certain proportion of traditional fuel oil type refineries transformed into chemical type refineries. However, under the crude oil processing flow of existing fuel oil type refineries, crude oil is usually cut and distilled into several narrow fractions and then processed separately to produce fuel oil. On the one hand, this leads to an insufficient proportion of crude oil converted into chemical raw materials, resulting in a low yield of chemical products in the product structure; on the other hand, during the process of chemical transformation of some fuel oil production equipment, there is also a risk of high equipment transformation investment costs or failure to produce qualified chemical raw materials after transformation.

CN101760235A discloses a method for hydrocracking heavy crude oil. In the presence of hydrogen, heavy crude oil with an API gravity of less than 20 is sequentially reacted with a hydrogenation protective agent, a hydrodemetallizing agent, a hydrodesulfurizing agent I, a hydrocracking agent and a hydrodesulfurizing agent II, and then separated to obtain a hydrotreated crude oil with an increased API gravity and reduced viscosity. However, although the method of the invention can obtain a hydrotreated crude oil with a reduced mass fraction of impurities such as metals, sulfur and nitrogen, it cannot meet the requirements for producing chemical raw materials with qualified properties.

CN105358661A and CN109593556A disclose a method and facility for converting crude oil into petrochemical products with improved propylene yield. The method firstly produces gas, kerosene and/or crude diesel oil and residual oil by distilling crude oil, and then produces LPG and reformed effluent by upgrading the residual oil; and then carries out at least 50% aromatic ring opening of the reformed effluent with kerosene and crude diesel oil to produce petrochemical products.

CN104093821B discloses a hydroprocessing and steam pyrolysis method for directly processing crude oil, including hydrogen redistribution and integration. The method first separates crude oil into light components and heavy components, wherein the heavy components are hydrogenated to produce an effluent with reduced pollutant content, paraffin content and BMCI value, and then the heavy fraction hydrogenation effluent and the light components enter a steam pyrolysis zone to produce olefins and aromatic chemicals.

CN106103664A discloses an integrated hydrocracking method. In the method, crude oil and raw materials from coking are hydrotreated in the first hydrocracking reaction zone to obtain a stream separated into LPG and a liquid stream, the liquid stream enters the second hydrocracking zone for reaction to produce a BTXE stream, a stream containing an LPG stream and residual liquid, and the residual liquid stream is thermally cracked to produce a coking liquid product and petroleum coke.

Summary of the invention

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

The hydrogenation method for producing chemical raw materials from crude oil provided by the present invention comprises: the crude oil raw material sequentially passes through a first pretreatment reaction zone, a second pretreatment reaction zone, a hydrofining reaction zone and a hydrocracking reaction zone, and the reaction effluent is separated into gas and liquid and then enters a fractionation tower, and fractionation is performed to obtain liquefied gas, naphtha fraction, light catalytic cracking raw material, and heavy catalytic cracking raw material, wherein:

(1) The first pretreatment reaction zone is graded and filled with a first hydrogenation protective agent and a first hydrogenation demetallization agent, and the first pretreatment reaction zone controls the removal rate of metallic iron and calcium to be ≮70%;

The second pretreatment reaction zone is graded and filled with a second hydrogenation protective agent and a second hydrogenation demetallization agent, and the first pretreatment reaction zone and the second pretreatment reaction zone are controlled to have a total demetallization rate of ≮90% and a total deasphaltene rate of ≮90%;

(2) The hydrotreating reaction zone is filled with a hydrotreating catalyst, and the conversion depth of the hydrotreating reaction zone is controlled to control the mass fraction of aromatics in the fraction of >350°C in the hydrotreating product oil to be no more than 20%;

(3) The hydrocracking reaction zone is loaded with a hydrocracking catalyst, and the conversion depth of the hydrocracking reaction zone is controlled to control the conversion rate of the fraction >350°C to be 10% to 50%.

In the present invention, the crude oil raw material is a single crude oil or a mixture of multiple crude oils, and the source of the crude oil is not limited. Preferably, the API gravity of the crude oil raw material is ≮27, and the nitrogen content is ≯2500μg/g. Further preferably, the Fe content in the crude oil raw material is ≯40μg/g, the Ca content is ≯40μg/g, the Ni content is ≯20μg/g, the V content is ≯20μg/g, the residual carbon mass fraction is ≯15%, and the asphaltene content is ≯5000μg/g.

In one preferred embodiment of the present invention, after dehydration and desalting, the crude oil feedstock is contacted with the first hydrogenation protective agent and the first hydrogenation demetallization agent in the first pretreatment reaction zone in sequence to mainly carry out hydrogenation deironization and hydrogenation decalcification reactions. The reaction effluent of the first pretreatment reaction zone enters the second pretreatment reaction zone without separation, and contacts with the second hydrogenation protective agent and the second hydrogenation demetallization agent to carry out hydrogenation demetallization and hydrogenation deasphaltenes. Alternatively, in another preferred embodiment of the present invention, the reaction effluent of the first pretreatment reaction zone is subjected to gas-liquid separation, the hydrogen-rich gas obtained by separation is recycled, and the liquid stream obtained by separation enters the second pretreatment reaction zone for further reaction.

In a preferred embodiment of the present invention, the reaction pressure of the first pretreatment reaction zone is lower than the reaction pressure of the second pretreatment reaction zone, and the reaction pressure of the first pretreatment reaction zone is ≯8 MPa.

In a preferred case, the reaction conditions of the first pretreatment reaction zone are: reaction pressure of 2.0 MPa to 7.9 MPa, reaction temperature of 260°C to 420°C, liquid hourly volume space velocity of 0.5 h ^-1 to 15 h ^-1 , hydrogen to oil volume ratio of 50 to 600;

The reaction conditions of the second pretreatment reaction zone are as follows: reaction pressure of 8.0 MPa to 20.0 MPa, reaction temperature of 260° C. to 420° C., liquid hourly space velocity of 0.5 h ^-1 to 15 h ^-1 , and hydrogen to oil volume ratio of 300 to 2000.

In a preferred case, according to the direction of the reactant flow, the first pretreatment reaction zone is sequentially filled with the first hydrogenation protective agent and the first hydrogenation demetallization agent, and the filling volume ratio of the first hydrogenation protective agent to the first hydrogenation demetallization agent is 1:3 to 2:1;

The first hydrogenation protective 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, and based on the total weight of the first hydrogenation protective agent, the content of the Group VIII metal is 0.3 wt% to 5 wt%, and the content of the Group VIB metal is 1 wt% to 10 wt% in terms of oxide;

The first hydrodemetallization agent comprises a carrier and an active metal component, wherein 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, and the Group VIB metal is selected from molybdenum and/or tungsten. Based on the total weight of the first hydrodemetallization agent, the content of the Group VIII metal is 1 wt% to 5 wt%, and the content of the Group VIB metal is 1 wt% to 15 wt%, calculated as oxide.

In one preferred embodiment of the present invention, at least two or more first hydrodemetallization agents are loaded in the first pretreatment reaction zone, and along the direction of the reactant flow, the particle size of the first hydrodemetallization agent gradually decreases, and the mass fraction of the active metal component gradually increases.

In a preferred case, according to the direction of the reactant flow, the second pretreatment reaction zone is sequentially filled with the second hydrogenation protective agent and the second hydrogenation demetallization agent, and the filling volume ratio of the second hydrogenation protective agent to the second hydrogenation demetallization agent is 1:6 to 1:1;

The second hydrogenation protective agent comprises a carrier and an active metal component, wherein 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, and based on the total weight of the second hydrogenation protective agent, the content of the Group VIII metal is 0.3 wt% to 5 wt%, and the content of the Group VIB metal is 1 wt% to 10 wt% in terms of oxide;

The second hydrodemetallization agent comprises a carrier and an active metal component, wherein 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, and the Group VIB metal is selected from molybdenum and/or tungsten. Based on the total weight of the second hydrodemetallization agent, the content of the Group VIII metal is 1 wt% to 5 wt%, and the content of the Group VIB metal is 1 wt% to 15 wt%, calculated as oxide.

In one preferred embodiment of the present invention, at least two or more second hydrogenation protective agents are loaded in the second pretreatment reaction zone, and along the direction of the reactant flow, the particle size of the second hydrogenation protective agent gradually decreases, and the mass fraction of the active metal component gradually increases;

At least two or more second hydrodemetallization agents are loaded in the second pretreatment reaction zone. Along the direction of the reactant flow, the particle size of the second hydrodemetallization agent gradually decreases, and the mass fraction of the active metal component gradually increases.

In a preferred case, the hydrogen source of the first pretreatment reaction zone is a sulfur-containing hydrogen-rich gas selected from one or more of circulating hydrogen before desulfurization, dry gas before desulfurization, and low-fraction gas before desulfurization, and the sulfide concentration of the sulfur-containing hydrogen-rich gas is 5000μL/L to 50000μL/L.

In one preferred embodiment of the present invention, two or more rotating reactors are arranged in the first pretreatment reaction zone, and the crude oil feedstock enters at least one of the reactors. When the pressure drop of the online reactor into which the crude oil feedstock enters rises to a limited value, the crude oil feedstock can be selectively switched to another reactor, the online reactor with a high pressure drop is cut out, and the first hydrogenation protective agent and the first hydrogenation demetallization agent are replaced.

In one preferred embodiment of the present invention, a rotating reactor is not provided in the first pretreatment reaction zone. When the pressure drop in the first pretreatment reaction zone reaches more than 80% of the pressure drop design value, the crude oil feedstock no longer enters the first pretreatment reaction zone, but directly enters the second pretreatment reaction zone for reaction. The first hydrogenation protective agent and the first hydrogenation demetallization agent in the first pretreatment reaction zone can be replaced; or they can be replaced without replacement, and the catalyst can be replaced together after the entire crude oil hydrogenation unit is shut down.

The present invention sets a low-pressure first pretreatment reaction zone to remove metal impurities such as iron and calcium that have a greater impact on the life of the hydrogenation catalyst, and effectively extends the operation cycle of the entire crude oil hydrogenation device by flexibly switching the treatment implementation method.

In the present invention, the reaction effluent of the second pretreatment reaction zone directly enters the hydrofining reaction zone without separation, contacts with the hydrofining catalyst, and undergoes hydrodesulfurization, hydrodenitrogenation and partial saturation of aromatics. In a preferred case, the reaction conditions of the hydrofining reaction zone are: reaction pressure of 8.0 MPa to 20.0 MPa, reaction temperature of 280°C to 400°C, liquid hourly volume space velocity of 0.5 h ^-1 to 6 h ^-1 , and hydrogen to oil volume ratio of 300 to 2000.

In order to obtain high-quality chemical raw materials, the present invention controls the conversion depth of the hydrofining reaction zone. In a preferred case, the conversion depth of the hydrofining reaction zone is to control the mass fraction of aromatics in the >350°C fraction in the hydrofining product oil to be no more than 16%.

In a preferred case, the hydrorefining catalyst is a catalyst of at least one metal selected from Group VIB, or at least one metal selected from Group VIII, or a combination thereof, supported on an alumina or/and alumina-silicon oxide carrier. Further preferably, the Group VIII metal is selected from nickel and/or cobalt, and the Group VIB metal is selected from molybdenum and/or tungsten, and the content of the nickel and/or cobalt is 1 wt% to 15 wt%, and the content of the molybdenum and/or tungsten is 5 wt% to 40 wt%, based on the total weight of the hydrorefining catalyst, calculated as oxide.

In the present invention, a gas-liquid separation device may be provided between the hydrofining reaction zone and the hydrocracking reaction zone, or no gas-liquid separation device may be provided. When no gas-liquid separation device is provided, 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 the hydrofining product oil. Preferably, a gas-liquid separation device is provided, and the hydrofining reaction effluent is subjected to gas-liquid separation to obtain hydrogen-rich gas and hydrofining product oil. The hydrofining product oil enters the hydrocracking reaction zone and contacts with the hydrocracking catalyst to carry out the hydrocracking reaction.

In a preferred case, the reaction conditions of the hydrocracking reaction zone are: reaction pressure of 8.0 MPa to 20.0 MPa, reaction temperature of 290°C to 420°C, liquid hourly volume space velocity of 0.3 h ^-1 to 5 h ^-1 , hydrogen to oil volume ratio of 300 to 2000;

In order to obtain high-quality chemical raw materials, the present invention controls the conversion depth of the hydrocracking reaction zone, and the conversion depth of the hydrocracking reaction zone is to control the conversion rate of the fraction >350°C to be 10% to 50%.

In the present invention, the conversion rate of the fraction >350°C is: 100*(mass fraction of fraction >350°C in the feedstock - mass fraction of fraction >350°C in the hydrocracking oil)/mass fraction of fraction >350°C in the feedstock

In a preferred case, the hydrocracking catalyst comprises a carrier and an active metal component supported on the carrier, the carrier is composed of a heat-resistant 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 Group VIB metals and Group VIII metals; based on the hydrocracking catalyst as a whole, calculated as oxide, the Group VIB metal is 15% to 35% by weight, the Group VIII metal is 2% to 8% by weight, based on the carrier, the Y-type molecular sieve is 3% to 35% by weight, and the remainder is the heat-resistant inorganic oxide.

In one preferred embodiment of the present invention, a post-hydrogenation catalyst is loaded in the lower part of the hydrocracking reaction zone, and the loading ratio of the hydrocracking catalyst to the post-hydrogenation catalyst is 8: 1 to 15: 1. According to the logistics direction, the hydrorefining product oil passes through the hydrocracking catalyst and the post-hydrogenation catalyst in sequence.

In the present invention, the post-hydrogenation refining catalyst loaded in the lower part of the hydrocracking reaction zone and the hydrofinishing catalyst loaded in the hydrofinishing reaction zone may be the same as or different from each other.

In a preferred case, the post-hydrogenation refining catalyst is a catalyst of at least one metal selected from Group VIB, or at least one metal selected from Group VIII, or a combination thereof, supported on an alumina or/and alumina-silicon oxide carrier. Further preferably, the Group VIII metal is selected from nickel and/or cobalt, and the Group VIB metal is selected from molybdenum and/or tungsten, and based on the total weight of the post-hydrogenation refining catalyst, the content of the nickel and/or cobalt is 1 wt% to 15 wt%, and the content of the molybdenum and/or tungsten is 5 wt% to 40 wt%, calculated as oxides.

In the present invention, the hydrocracking reaction effluent is subjected to gas-liquid separation to obtain hydrogen-rich gas and hydrocracking product oil, and the hydrocracking product oil enters a fractionation tower and is fractionated to obtain chemical raw materials such as liquefied gas, naphtha fraction, light catalytic cracking raw material, and heavy catalytic cracking raw material. Among them, the cutting point between the naphtha fraction and the light catalytic cracking raw material is 130-160°C, preferably 140°C; the cutting point between the light catalytic cracking raw material and the heavy catalytic cracking raw material is 330-380°C, preferably 350°C.

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

The catalytic cracking process of the present invention refers to a process in which petroleum hydrocarbons are cracked at high temperature in the presence of a catalyst to produce low-carbon olefins such as ethylene, propylene, butene, and simultaneously produce light aromatics. Specifically, it can be one or more of a catalytic cracking process (DCC process), a catalytic thermal cracking process (CPP process), a heavy oil direct cracking process for producing ethylene (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 present invention are both high-quality raw materials for the catalytic cracking process, and the obtained light olefin yield is high and the product yield is high. Specifically, the hydrogen mass fraction of the light catalytic cracking raw material obtained by the present invention is ≮13.5%, and the UOP K value of the light catalytic cracking raw material is ≮12. The hydrogen mass fraction of the heavy catalytic cracking raw material obtained by the present invention is ≮13.5%.

The inventors of the present invention have found through in-depth research that the higher the hydrogen mass fraction of the catalytic cracking feedstock, the higher the olefin content in the catalytic cracking product. When the hydrogen mass fraction of the catalytic cracking feedstock is controlled to be ≮13.5%, a good catalytic cracking product yield can be obtained. In addition, the economic efficiency of the catalytic cracking unit is positively correlated with the UOPK value of the feedstock. Usually, the UOP K value of the feedstock is greater than 11.9, which can ensure that the catalytic cracking (DCC) unit begins to have good economic efficiency, and as the UOP K value of the feedstock increases, the yields of ethylene, propylene and butene in the catalytic cracking unit products gradually increase, and the economic efficiency of the unit gradually improves.

The UOP K value, also called the performance factor K, is calculated by the formula

Wherein, Tv is the volume average boiling point of the raw material, and d _15.6 is the density of the raw material at 15.6°C.

By adopting the treatment method provided by the present invention, crude oil is subjected to a hydrocracking method to produce high-quality chemical raw materials, especially a large amount of high-quality light catalytic cracking raw materials, wherein the light catalytic cracking raw materials satisfy the hydrogen mass fraction ≮13.5%, and the UOP K value ≮12. In addition, the heavy catalytic cracking raw materials obtained by the present invention satisfy the hydrogen mass fraction ≮13.5%, and are also high-quality catalytic cracking raw materials. By adopting the high-quality catalytic cracking raw materials, the catalytic cracking device can achieve the purpose of increasing the yield of high-value products of light olefins.

DETAILED DESCRIPTION

The following examples further illustrate the hydrogenation method for producing high-quality chemical materials from crude oil provided by the present invention, but the present invention is not limited thereto.

Comparative Example 1-1, Example 1-1

This group of comparative examples and embodiments is used to illustrate the effects of different properties of light catalytic cracking feedstock on the product yield of the catalytic cracking unit.

Table 1 lists the test results of two light catalytic cracking feedstocks in the DCC pilot plant.

The catalytic cracking catalyst used has a trade name of MMC-2, which is produced by the Qilu Branch of Sinopec Corporation.

The reaction conditions of the DCC device are: reaction temperature of 580°C, catalyst-oil ratio of 12, and steam injection amount of 25% by weight (of the raw material).

It can be seen from the data in Table 1 that two light catalytic cracking feedstocks with the same distillation range but different hydrogen content and UOP K values are reacted under the same catalytic cracking process conditions. The hydrogen mass fraction of light catalytic cracking feedstock 2 is greater than 13.5%, and the UOP K value is greater than 12, thereby obtaining a higher yield of light olefins (ethylene, propylene, butene).

Table 1

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

The yield of naphtha <140℃ is defined as: the weight percentage of the naphtha fraction (<140℃) cut by the fractionation tower to the raw material;

The light catalytic cracking feed yield is defined as: the weight percentage of the light catalytic cracking feed (140°C to 350°C) cut from the full fraction product through the fractionation tower to the feed;

The heavy catalytic cracking feedstock yield is defined as the weight percentage of the heavy catalytic cracking feedstock (>350°C) cut out of the full fraction product through the distillation tower to the feedstock.

The first hydrogenation protective agent, the first hydrogenation demetallization agent, the second hydrogenation protective agent, the second hydrogenation demetallization agent, the hydrogenation refining catalyst, the hydrocracking catalyst and the post-hydrogenation refining catalyst used in the present invention are all produced by Sinopec Catalyst Branch.

Comparative Example 1

After the feedstock E is mixed with hydrogen, it passes through the first pretreatment reaction zone, the second pretreatment reaction zone, the hydrofining reaction zone and the hydrocracking reaction zone in sequence, and contacts and reacts with the first hydroprotecting agent, the first hydrodemetallizing agent, the second hydroprotecting agent, the second hydrodemetallizing agent, the hydrofining catalyst, the hydrocracking catalyst and the post-hydrofining catalyst in sequence, and the mass fraction of aromatics in the fraction >350°C in the hydrofining oil is controlled to be 18%; the conversion depth of the hydrocracking reaction zone is controlled to control the conversion rate of the fraction >350°C to be 50%. The reaction effluent of the hydrocracking reaction zone is separated to obtain a naphtha fraction <140°C, a light catalytic cracking raw material fraction of 140°C to 350°C and a heavy catalytic cracking raw material fraction >350°C. The process condition parameters and product yields and property data of the experiment are listed in Table 3.

It can be seen from the data in Table 3 that under the experimental process conditions, the overall demetallization rate of the first and second pretreatment reaction zones of raw material E is 88%; the hydrogen mass fraction of the obtained light catalytic cracking raw material is 13.88%, and the UOP K value is 11.1; the hydrogen mass fraction of the obtained heavy catalytic cracking raw material is 13.40%, and the UOP K value is 11.7. On the one hand, the above data show that neither the light nor heavy catalytic cracking raw materials obtained from raw material E can be used as high-quality catalytic cracking raw materials. On the other hand, due to the insufficient metal removal rate in the pretreatment reaction zone, the life of the downstream hydrotreating catalyst will be shortened, thereby affecting the operation cycle of the entire device.

Example 1, Example 2 and Example 3

The raw materials B, C and D used in Examples 1, 2 and 3 are respectively mixed with hydrogen and passed through the first pretreatment reaction zone, the second pretreatment reaction zone, the hydrofining reaction zone and the hydrocracking reaction zone in sequence, and then contacted with the first hydroprotecting agent, the first hydrodemetallizing agent, the second hydroprotecting agent, the second hydrodemetallizing agent, the hydrofining catalyst, the hydrocracking catalyst and the post-hydrofining catalyst for reaction, and the mass fraction of aromatic hydrocarbons in the hydrofining oil>350°C fraction is controlled to be 8%, 10% and 13% respectively, and the conversion depth of the hydrocracking reaction zone is controlled to be 10%, 36% and 43% respectively for the conversion rate of the>350°C fraction, and the reaction effluent of the hydrocracking reaction zone is separated to obtain a naphtha fraction<140°C, a light catalytic cracking raw material fraction of 140°C to 350°C and a heavy catalytic cracking raw material fraction>350°C. The process condition parameters and product yields and property data of the experiment are listed in Table 3.

It can be seen from the data in Table 3 that, under the experimental process conditions, the iron removal rate and calcium removal rate of the first pretreatment reaction zone of raw materials B, C and D are both greater than 70%, and the overall demetallization rate of the first and second pretreatment reaction zones is greater than 90%. The hydrogen mass fractions of the obtained light catalytic cracking raw materials are 14.05%, 14.03% and 13.75%, respectively, and the UOP K values are 12.3, 12.2 and 12.0, respectively; the hydrogen mass fractions of the obtained heavy catalytic cracking raw materials are 14.05%, 14.03% and 13.75%, respectively, and the UOP K values are 12.6, 12.4 and 12.4, respectively. The above data show that by adopting the method provided by the present invention, the light and heavy catalytic cracking raw materials obtained can be used as high-quality catalytic cracking raw materials.

Comparative Example 2

After the raw material D is mixed with hydrogen, it passes through the pretreatment reaction zone, the hydrofining reaction zone and the hydrocracking reaction zone in sequence, and contacts and reacts with the hydrogenation protective agent, the hydrodemetallization agent, the hydrofining catalyst, the hydrocracking catalyst and the post-hydrofining catalyst in sequence, and the mass fraction of aromatic hydrocarbons in the hydrofining oil>350℃ is controlled to be 23%, and the conversion depth of the hydrocracking reaction zone is controlled to be 40% for the conversion rate of the fraction>350℃. The reaction effluent of the hydrocracking reaction zone is separated to obtain a naphtha fraction<140℃, a light catalytic cracking raw material fraction of 140℃～350℃ and a heavy catalytic cracking raw material fraction>350℃. The process condition parameters and product yields and property data of the experiment are listed in Table 4.

It can be seen from the data in Table 4 that under the experimental process conditions, the demetallization rate of the pretreatment reaction zone of raw material D is 95%; the hydrogen mass fraction of the obtained light catalytic cracking raw material is 13.75%, and the UOP K value is 11.3; the hydrogen mass fraction of the obtained heavy catalytic cracking raw material is 13.52%, and the UOP K value is 11.6. The above data show that the light and heavy catalytic cracking raw materials obtained from raw material D under this process conditions cannot be used as high-quality catalytic cracking raw materials.

Example 4

After the raw material D is mixed with hydrogen, it passes through the first pretreatment reaction zone, the second pretreatment reaction zone, the hydrofining reaction zone and the hydrocracking reaction zone in sequence, and contacts and reacts with the first hydroprotecting agent, the first hydrodemetallizing agent, the second hydroprotecting agent, the second hydrodemetallizing agent, the hydrofining catalyst, the hydrocracking catalyst and the post-hydrofining catalyst in sequence, and the mass fraction of aromatic hydrocarbons in the hydrofining oil>350℃ is controlled to be 16%, and the conversion depth of the hydrocracking reaction zone is controlled to control the conversion rate of the>350℃ fraction to be 40%. The reaction effluent of the hydrocracking reaction zone is separated to obtain a naphtha fraction <140℃, a light catalytic cracking raw material fraction of 140℃～350℃ and a heavy catalytic cracking raw material fraction>350℃. The process condition parameters and product yields and property data of the experiment are listed in Table 4.

It can be seen from the data in Table 4 that, under the experimental process conditions, the iron removal rate and calcium removal rate of the first pretreatment reaction zone of raw material D are 82% and 75% respectively, the overall demetallization rate of the first and second pretreatment reaction zones is 97%, the hydrogen mass fraction of the obtained light catalytic cracking raw material is 14.18%, and the UOP K value is 12.0; the hydrogen mass fraction of the obtained heavy catalytic cracking raw material is 13.92%, and the UOP K value is 12.3. The above data show that the light and heavy catalytic cracking raw materials obtained by the method provided by the present invention can be used as high-quality catalytic cracking raw materials.

Under the condition that the liquid hourly volume space velocity of the two pretreatment units is consistent, the first pretreatment reaction zone can remove iron and calcium from the crude oil at low pressure, which can effectively save operating costs on the one hand, and reduce the burden of metal removal in the high-pressure pretreatment reaction zone on the other hand, thereby achieving the effect of improving the metal removal rate of the pretreatment reaction zone within the effective operating cycle.

Comparative Example 3

After the feedstock B is mixed with hydrogen, it passes through the first pretreatment reaction zone, the second pretreatment reaction zone, the hydrofining reaction zone and the hydrocracking reaction zone in sequence, and contacts and reacts with the first hydroprotecting agent, the first hydrodemetallizing agent, the second hydroprotecting agent, the second hydrodemetallizing agent, the hydrofining catalyst, the hydrocracking catalyst and the post-hydrofining catalyst in sequence, and the mass fraction of aromatic hydrocarbons in the hydrofining oil>350℃ fraction is controlled to be 15%, the conversion depth of the hydrocracking reaction zone is controlled to be 7% for the>350℃ fraction conversion rate, and the reaction effluent of the hydrocracking reaction zone is separated to obtain a naphtha fraction <140℃, a light catalytic cracking raw material fraction of 140℃～350℃ and a heavy catalytic cracking raw material fraction>350℃. The process condition parameters of the experiment and the product yield and property data are listed in Table 5.

It can be seen from the data in Table 5 that the hydrogen mass fraction of the light catalytic cracking feedstock obtained by raw material B under the experimental process conditions is 13.95%, and the UOP K value is 11.6; the hydrogen mass fraction of the heavy catalytic cracking feedstock obtained is 13.67%, and the UOP K value is 12.0. The above data show that although the raw material B with better properties is used, the light catalytic cracking feedstock obtained cannot be used as a high-quality catalytic cracking feedstock.

Example 5

After the raw material B is mixed with hydrogen, it passes through the first pretreatment reaction zone, the second pretreatment reaction zone, the hydrofining reaction zone and the hydrocracking reaction zone in sequence, and contacts and reacts with the first hydroprotecting agent, the first hydrodemetallizing agent, the second hydroprotecting agent, the second hydrodemetallizing agent, the hydrofining catalyst, the hydrocracking catalyst and the post-hydrofining catalyst in sequence, and the mass fraction of aromatic hydrocarbons in the hydrofining oil>350℃ fraction is controlled to be 10%, the conversion depth of the hydrocracking reaction zone is controlled to be 10% for the>350℃ fraction conversion rate, and the reaction effluent of the hydrocracking reaction zone is separated to obtain a naphtha fraction <140℃, a light catalytic cracking raw material fraction of 140℃～350℃ and a heavy catalytic cracking raw material fraction>350℃. The process condition parameters of the experiment and the product yield and property data are listed in Table 5.

It can be seen from the data in Table 5 that the hydrogen mass fraction of the light catalytic cracking raw material obtained by raw material B under the experimental process conditions is 14.21%, and the UOP K value is 12.13; the hydrogen mass fraction of the heavy catalytic cracking raw material obtained is 14.0%, and the UOP K value is 12.21. The above data show that the light and heavy catalytic cracking raw materials obtained by raw material B using the method provided by the present invention can be used as high-quality catalytic cracking raw materials.

Table 2 Properties of crude oil after desalting

project Crude oil B Crude Oil C Crude oil D Crude Oil E API Degree 31.65 28.3 27.6 24.94 Density (20℃)/(g/cm ³ ) 0.8656 0.8820 0.8863 0.9005 Sulfur mass fraction/% 0.32 0.835 0.915 0.80 Nitrogen content/(μg/g) 282 840 1589 4100 Carbon residue value/weight% <0.3 <0.3 3.23 6.4 Asphaltene/(μg/g) <1000 <1000 1230 8500 Metal mass fraction/(μg/g) Fe 6.4 15.1 15.1 13.0 Ni 1.2 6.2 2.7 26.0 V 1.5 6.2 <0.1 1.6 Ca 2.5 26.4 8.0 8.9 >350℃ fraction, weight % 26.3 67.16 69.01 75

Table 3

Table 4

Table 5

Claims (15)

1. A hydrogenation method for producing chemical raw materials from crude oil sequentially passes through a first pretreatment reaction zone, a second pretreatment reaction zone, a hydrofining reaction zone and a hydrocracking reaction zone, and the obtained reaction effluent is subjected to gas-liquid separation and then enters a fractionating tower to be fractionated to obtain liquefied gas, naphtha fraction, light catalytic cracking raw materials and heavy catalytic cracking raw materials, wherein:

(1) The first pretreatment reaction zone is graded filled with a first hydrogenation protective agent and a first hydrodemetallization agent, and the first pretreatment reaction zone controls the removal rate of metallic iron and calcium to be no less than 70%;

the second pretreatment reaction zone is graded filled with a second hydrogenation protective agent and a second hydrodemetallization agent, and the total demetallization rate of the first pretreatment reaction zone and the second pretreatment reaction zone is controlled to be less than or equal to 90% and the total deasphalting rate is controlled to be less than or equal to 90%; the reaction pressure of the first pretreatment reaction zone is smaller than that of the second pretreatment reaction zone, the reaction pressure of the first pretreatment reaction zone is 2.0 MPa-7.9 MPa, the volume ratio of hydrogen to oil is 50-600, the reaction pressure of the second pretreatment reaction zone is 8.0 MPa-20.0 MPa, the volume ratio of hydrogen to oil is 300-2000, the hydrogen source of the first pretreatment reaction zone is sulfur-containing hydrogen-rich gas, and the sulfur concentration of the sulfur-containing hydrogen-rich gas is 5000 mu L/L-50000 mu L/L;

(2) The hydrofining reaction zone is filled with 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;

(3) 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 not more than 2500 mu g/g;

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

the UOP K value is calculated by a 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 ℃.

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. According to claim 1Process characterized in that the reaction conditions of the first pretreatment reaction zone: the reaction temperature is 260-420 ℃, and the liquid hourly space velocity is 0.5h ^-1 ～15h ^-1 ；

Reaction conditions in the second pretreatment reaction zone: the reaction temperature is 260-420 ℃, and the liquid hourly space velocity is 0.5h ^-1 ～15h ^-1 。

4. The method of claim 1, wherein the first pretreatment reaction zone is charged with the first hydroprotectant and the first hydrodemetallization agent in sequence in the direction of the reactant flow, the first hydroprotectant and the first hydrodemetallization agent being charged in a volumetric ratio of 1: 3-2: 1, a step of;

the first hydrogenation protective 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 first hydrogenation protective agent, and the content of the VIB group metal is 1-10 wt% based on oxide;

the first hydrodemetallization 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 total weight of the first hydrodemetallization agent is taken as a reference, the content of the VIII group metal is 1-5 wt% based on oxides, and the content of the VIB group metal is 1-15 wt%.

5. The process of claim 4 wherein the first pretreatment reaction zone is charged with at least two first hydrodemetallization agents having progressively smaller particle sizes and progressively higher mass fractions of the active metal component along the reactant flow direction.

6. The process of claim 1 wherein the second pretreatment reaction zone is charged with a second hydroprotectant and a second hydrodemetallization agent in sequence, in terms of reactant flow direction, the second hydroprotectant and second hydrodemetallization agent being charged in a volumetric ratio of 1: 6-1: 1, a step of;

the second hydrogenation protective 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 second hydrogenation protective agent, and the content of the VIB group metal is 1-10 wt% based on oxide;

the second hydrodemetallization 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 1-5 wt% based on the total weight of the second hydrodemetallization agent, and the content of the VIB group metal is 1-15 wt% based on oxide.

7. The process of claim 6 wherein at least two second hydroprotectants are charged into the second pretreatment reaction zone, the second hydroprotectants having progressively smaller particle sizes and progressively higher mass fractions of the active metal component along the reactant flow direction;

at least two second hydrodemetallization agents are filled in the second pretreatment reaction zone, the particle size of the second hydrodemetallization agents gradually becomes smaller along the direction of the reactant flow, and the mass fraction of the active metal components gradually increases.

8. The method of claim 1 wherein 1 or more than two rotatable reactors are provided in the first pretreatment reaction zone and the crude feed is introduced into at least one of the reactors.

9. The method according to claim 1, wherein when the pressure drop of the first pretreatment reaction zone reaches 80% of the design value of the pressure drop, the crude oil raw material does not enter the first pretreatment reaction zone any more, and directly enters the second pretreatment reaction zone, and the flow of the crude oil is switched to the first pretreatment reaction zone and the second pretreatment reaction zone after the catalyst of the cut first pretreatment reaction zone is replaced; or crude oil is cut out from the reactor of the first pretreatment reaction zone, the pressure drop of which reaches a design value, and the reactor of the first pretreatment reaction zone can be replaced, so that the flow of the raw oil is the first pretreatment reaction zone and the second pretreatment reaction zone; or directly cutting out the first pretreatment reaction zone and directly entering the second pretreatment reaction zone.

10. The process of claim 1 wherein the hydrofinishing reaction zone reaction conditions: the reaction pressure is 8.0 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 not more than 16% by mass fraction of aromatic hydrocarbon in fraction with the temperature of 350 ℃ in hydrofining generated oil.

11. The process according to claim 1, wherein the 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.

12. The process according to claim 11, characterized in that the group VIII metal is selected from nickel and/or cobalt and the group VIB metal is selected from molybdenum and/or tungsten in an amount of 1% to 15% by weight, calculated as oxide, and in an amount of 5% to 40% by weight, calculated as oxide, based on the total weight of the hydrofinishing catalyst.

13. The process of claim 1 wherein the hydrocracking reaction zone reaction conditions: the reaction pressure is 8.0 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.