METHOD AND APPARATUS FOR PRODUCING NEEDLE COKE USING MIXED FEEDS - Patent application

Abstract

The present invention relates to a method and apparatus for producing needle coke using a mixed feedstock. According to the present invention, needle coke with excellent mechanical properties can be produced. The needle coke production method of the present invention includes the following steps: (1) hydrotreating a mixture of a first feedstock and a second feedstock to obtain a hydrogenated product; (2) cracking the hydrogenated product to obtain a cracked product; and (3) producing needle coke using the cracked product as a starting material, wherein the aromatic carbon ratio of the first feedstock is greater than 65 mol%, the aromatic carbon ratio of the second feedstock is greater than 60 mol%, and the coking initiation temperature of the first feedstock is 10°C to 140°C lower than the coking initiation temperature of the second feedstock.

Description

[Technical Field]

[0001] The present invention relates to the technical field of petrochemical industry, and more particularly to a method and apparatus for producing needle coke using mixed feedstock oil. [Background technology]

[0002] Aromatic oils are high-quality starting materials for producing needle coke. For example, catalytic slurry oil and ethylene tar are preferred raw materials for producing oil-based needle coke. However, both have specific problems in the actual production process. Due to their high ash and sulfur content, catalytic slurry oil requires solid removal and hydrodesulfurization treatment, while ethylene tar typically requires colloid removal treatment due to its high colloid content.

[0003] CN110511785A discloses a method for preparing a starting material for needle coke from a catalyst slurry oil, specifically including first adding a low-molecular-weight linear alkane to the slurry oil, removing asphaltenes to obtain a supernatant liquid, extracting and decoagulating the supernatant liquid to obtain an aromatics-enriched oil, and subjecting the aromatics-enriched oil to hydrodesulfurization treatment to obtain a starting material for needle coke. In this method, a combined extraction-hydrogenation process is used to decoagulate and desulfurize the catalyst slurry oil so that it meets the requirements for being a starting material for needle coke.

[0004] CN103102974A discloses a method for producing clean fuel oil from ethylene tar, which includes separating ethylene tar into a light fraction and a heavy fraction, blending the heavy fraction with a conventional coking starting material, and obtaining coker gasoline and coker diesel by delayed coking, and the coker gasoline is subjected to hydrotreating, and the coker diesel is blended with the light fraction of ethylene tar and subjected to hydrotreating to obtain clean gasoline and diesel products. This method selects an appropriate processing method according to the composition properties of the ethylene tar fraction to improve the yield of light fuel oil.

[0005] During hydrodesulfurization of catalytic slurry oil, some of the carbon-carbon double bonds in the aromatic rings become saturated and converted to alkyl side chains. These aromatic hydrocarbons with alkyl side chains act as hydrogen donors during needle coke production, hindering the polymerization of molecules that form polymers. This results in incomplete mesophase development and affects the performance of needle coke products. Ethylene tar contains aromatic olefins, which have poor thermal stability and are prone to multiple condensation into coke under high-temperature conditions, affecting the long-term operation of the coking unit. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the present invention provides a method and apparatus for producing needle coke using mixed feedstock oil, which can effectively solve the problems of poor quality of needle coke produced due to hydrotreating of catalyst slurry oil and short operation period of delayed coking unit due to poor thermal stability of ethylene tar.

[0007] Specifically, in a first aspect, the present invention provides a method for producing a medicament for the treatment of a medicament comprising the steps of: (1) hydrotreating a mixture of a first feedstock and a second feedstock to obtain a hydrotreated product; (2) cracking the hydrogenated product to obtain a cracked product; and (3) producing the needle coke using the cracked product as a starting material, The present invention relates to a method for producing needle coke, wherein the first feedstock has an aromatic carbon ratio of more than 65 mol% (preferably 70 mol% to 95 mol%), the second feedstock has an aromatic carbon ratio of more than 60 mol% (preferably 70 mol% to 90 mol%), and the coking initiation temperature of the first feedstock is 10°C to 140°C, preferably 35°C to 105°C, lower than the coking initiation temperature of the second feedstock.

[0008] Furthermore, in a second aspect, the present invention provides a compound comprising the following units: a feedstock supply unit configured to supply a first feedstock and a second feedstock; a hydrotreating unit configured to hydrotreat a mixture of the first feedstock and the second feedstock to obtain a hydrotreated product; a cracking unit configured to crack the hydrogenation product to obtain a cracked product; a needle coke production unit configured to produce needle coke using the cracked product as a starting material; The present invention relates to an apparatus for producing needle coke, wherein the aromatic carbon content of the first feedstock is greater than 65 mol% (preferably 70 mol% to 95 mol%), the aromatic carbon content of the second feedstock is greater than 60 mol% (preferably 70 mol% to 90 mol%), and the coking initiation temperature of the first feedstock is 10°C to 140°C, preferably 35°C to 105°C, lower than the coking initiation temperature of the second feedstock. [Effects of the Invention]

[0009] Compared with the prior art, the method and apparatus for producing needle coke using mixed stock oil provided by the present invention has one, or a combination of all or part of the following advantages: (1) According to the present invention, in a preferred embodiment, ethylene tar is first subjected to an extraction unit to remove colloids / asphaltenes to obtain an aromatics-enriched oil, and then the aromatics-enriched oil is separated into a first light oil and a first heavy oil according to their distillation ranges. The first light oil is rich in two-ring aromatics. The first heavy oil is rich in three-ring or higher aromatics, and the first heavy oil is a high-quality starting material for producing needle coke. The condensation product obtained after the condensation reaction of the first light oil is mixed with the colloid / asphaltenes-rich raffinate phase obtained from the extraction unit to produce low-sulfur petroleum coke. The addition of the condensation product can improve the dispersion of colloids / asphaltenes in the raffinate phase, avoid colloid / asphaltenes precipitation and coking in the furnace, and improve the quality and yield of low-sulfur petroleum coke.

[0010] (2) In a preferred embodiment of the present invention, the catalyst slurry oil is mixed with the first heavy oil and the mixture is sent to a hydrogenation reaction unit. Because the first heavy oil (derived from ethylene tar) contains aromatic olefins, the carbon-carbon double bonds of the olefins are more easily hydrogenated than the carbon-carbon double bonds of the aromatic rings. Therefore, in the hydrogenation reaction unit, the carbon-carbon double bonds of the olefins in the first heavy oil are preferentially saturated, followed by the hydrodesulfurization reaction of the catalyst slurry oil, and finally the carbon-carbon double bonds of the aromatic hydrocarbons are saturated. The existence of competing reactions effectively reduces the aromatic ring saturation rate of the catalyst slurry oil and avoids the production of excessive aromatic hydrocarbons with multiple alkyl or cycloalkyl side chains, which reduces the number of aromatic hydrocarbon rings and affects the mechanical properties of needle coke.

[0011] (3) According to the present invention, in a preferred embodiment, the hydrogenated tail oil is sent to a cracking reaction unit to cleave saturated aromatic side chains during hydrotreating, and the molecules are converted back into aromatic structures with short side chains. The separated middle distillate oil (containing a fraction of tricyclic and tetracyclic aromatics) is more suitable as a starting material for producing needle coke. The second light oil is a cracking product rich in low-molecular-weight hydrocarbons. If it is returned to the hydrotreating unit, the naphtha yield can be increased. If the second light oil is condensed and then sent to a low-sulfur petroleum coke production unit, it can be further condensed deeply to produce low-sulfur petroleum coke, thereby improving the utilization value of petroleum products.

[0012] (4) In a preferred embodiment, the present invention provides a method for producing needle coke by separating the tricyclic aromatics- and tetracyclic aromatics-rich fractions, leaving the remaining fraction rich in aromatics or colloids / asphaltenes and containing very low sulfur, making it a high-quality starting material for producing low-sulfur petroleum coke. The present invention utilizes the components in the starting material in a stepwise manner, significantly improving the effective utilization of catalyst slurry oil and ethylene tar. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic diagram of a process for producing needle coke using mixed stock provided by the present invention. [Figure 2] 1 shows the change in TI content of catalyst slurry oil used in Examples and Comparative Examples depending on the reaction temperature. [Figure 3] 1 shows the change in the TI content of the first feedstock used in Example 1 depending on the reaction temperature. [Figure 4] 1 shows the change in the TI content of the first feedstock used in Example 2 depending on the reaction temperature. [Figure 5] 1 is a photograph of the polarized microstructure of needle coke obtained in Example 2. [Figure 6] 1 shows the change in the TI content of the first feedstock used in Example 3 depending on the reaction temperature. [Figure 7] 1 is a photograph of the polarized microstructure of the needle coke obtained in Example 3. [Figure 8] 1 shows the change in the TI content of the first feedstock used in Example 4 depending on the reaction temperature. [Figure 9] 1 shows the change in the TI content of ethylene tar used in Comparative Example 2 depending on the reaction temperature. [Figure 10] 1 is a photograph of the polarized microstructure of needle coke obtained in Comparative Example 2. [Figure 11] 1 is a photograph of the polarized microstructure of the needle coke obtained in Comparative Example 3. [Figure 12] 10 shows the change in pressure over time in the furnace tube of the heating furnace of the needle coke production unit of Comparative Example 5. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, specific embodiments of the present invention will be described in detail, but it should be noted that the protection scope of the present invention is not limited by these specific embodiments, but is determined by the appended claims.

[0015] All publications, patent applications, patents and other documents mentioned in this specification are incorporated herein by reference.Unless otherwise defined, all technical and scientific terms used in this specification have the meaning that is commonly understood by those skilled in the art.If there is any discrepancy, the definition in this specification shall prevail.

[0016] When this specification uses the prefix "well-known to those skilled in the art," "prior art," or similar expressions to introduce materials, substances, methods, steps, apparatus, or components, the subject matter introduced by the prefix includes those that are conventionally used in the art at the time this application is filed, but also those that are no longer in common use but that become generally recognized in the art as being suitable for similar purposes.

[0017] Unless expressly stated otherwise, throughout this specification and claims, the terms "comprise / include / contain" or variations such as "comprises / includes / contains" or "comprising / including / containing" are understood to include the stated elements or components but not to exclude other elements or components.

[0018] In the context of this specification, for convenience of explanation, spatially relative terms such as "low," "bottom," "below," "lower," "high," "top," "upper," and the like may be used in the accompanying drawings to describe the relationship between one element or feature and another. It should be understood that spatially relative terms are intended to encompass different orientations of objects in use or operation in addition to the orientation depicted in the figures. For example, if an object in a figure is turned over, an element described as being "below" or "below" another element or feature would be oriented "above" or "above" the other element or feature. Thus, the exemplary term "below" can encompass two directions: "below" and "upper." Objects may also have other orientations (e.g., rotated 90 degrees or other orientations), and the spatially relative terms used herein should be interpreted accordingly.

[0019] In the context of this specification, terms such as "first", "second", etc. are used to distinguish between two different elements or parts, but are not used to limit a particular position or relative relationship.

[0020] In the context of this specification, all numerical values ​​of parameters (e.g., amounts or conditions) are understood to be modified in all instances by the term "about," whether or not "about" actually appears before the numerical value.

[0021] In the context of this specification, catalytic slurry oil refers to heavy distillate oil produced by catalytic cracking reactions.

[0022] In the context of this specification, ethylene tar refers to the heavy distillate produced by an ethylene cracking unit.

[0023] In the context of this specification, the sulfur content of the coke is determined by the method of GB / T 24526.

[0024] In the context of this specification, the Hardgrove Grindability Index of a coke is measured by the method of GB / T 2565.

[0025] In the context of this specification, the strength of the coke particles is measured as described in Annex B of T / ZGTS 002.

[0026] In the context of this specification, the ash content of the coke is determined by the method of GB / T 1429.

[0027] In the context of this specification, the ash content of the oil product is measured by the method of GB / T 508.

[0028] In the context of this specification, the sulfur content of the oil product is determined by the method of SH / T 0689.

[0029] In the context of this specification, the aromatic carbon ratio of the oil product is determined by the method of SH / T 0793.

[0030] In the context of this specification, the coking onset temperature is measured as follows: after leaving the feedstock at a certain temperature for 20 minutes, the toluene insolubles (TI) content is analyzed. When the TI content exceeds 0.5 wt%, the feedstock is considered to have started to coke, and the temperature at this point is taken as the coking onset temperature of the feedstock.

[0031] Unless otherwise stated, all percentages, parts, ratios, etc. referred to herein are by weight and pressures refer to gauge pressures.

[0032] In the context of this specification, any two or more embodiments of the present invention can be arbitrarily combined, and the technical solutions thus formed belong to the original disclosure of this specification and also belong to the protection scope of the present invention.

[0033] According to one embodiment of the present invention, there is provided a method for producing needle coke. According to the present invention, the method for producing needle coke is carried out in an apparatus for producing needle coke, which will be described later. Therefore, for the content not described in detail in the section on the method for producing needle coke, direct reference can be made to the relevant content described later on regarding the apparatus for producing needle coke.

[0034] According to one embodiment of the present invention, a method for producing needle coke comprises the following steps: (1) hydrotreating a mixture of a first feedstock and a second feedstock to obtain a hydrotreated product; (2) cracking the hydrogenated product to obtain a cracked product; (3) A process for producing needle coke using the cracked product as a starting material.

[0035] According to one embodiment of the present invention, the first feedstock has an aromatic carbon ratio of more than 65 mol% (preferably 70 mol% to 95 mol%). If the aromatic carbon ratio is too low, it means that the content of aromatic hydrocarbons is too low or the aromatic rings contain too many side chains. After hydrotreatment, the aromatic carbon ratio further decreases, making the first feedstock unsuitable as a starting material for producing needle coke.

[0036] According to one embodiment of the present invention, the second feedstock has an aromatic carbon ratio of more than 60 mol% (preferably 70 mol% to 90 mol%). If the aromatic carbon ratio is too low, it means that the content of aromatic hydrocarbons is too low or the aromatic rings contain too many side chains. After hydrotreatment, the aromatic carbon ratio further decreases, making the second feedstock unsuitable as a starting material for producing needle coke.

[0037] According to one embodiment of the present invention, the coking initiation temperature of the first feedstock is 10°C to 140°C, preferably 35°C to 105°C, lower than the coking initiation temperature of the second feedstock. If the coking initiation temperature of the first feedstock is too low, coking is likely to occur in the hydrotreating reactor, preventing the reaction from proceeding. If the coking initiation temperature of the first feedstock is too high or is similar to the coking initiation temperature of the second feedstock, the hydrotreating saturation capacity of the first feedstock will be similar to that of the second feedstock in the hydrotreating system, preventing the aromatic ring saturation of the second feedstock from being alleviated, resulting in an excessive decrease in the aromatic carbon ratio of the second feedstock after hydrotreating.

[0038] According to one embodiment of the present invention, the weight ratio of the second feedstock to the first feedstock is 1:1 to 1:0.001 (preferably 1:0.2 to 1:0.01).

[0039] According to one embodiment of the present invention, the first feedstock has a coking start temperature of 350°C to 420°C, preferably 380°C to 415°C.

[0040] According to one embodiment of the present invention, the second feedstock has a coking start temperature of 430°C to 490°C, preferably 450°C to 485°C.

[0041] According to one embodiment of the present invention, the second feedstock oil is a catalyst slurry oil. Generally, the ash content of the catalyst slurry oil can meet the above requirements after the deagglomeration treatment, and the deagglomeration treatment can be carried out by one or several combinations of filtration, centrifugal sedimentation, flocculation sedimentation, electrostatic adsorption, or other methods, and is preferably carried out by filtration.

[0042] According to one embodiment of the present invention, the second feedstock has an ash content of 0.01 wt% or less, preferably 0.005 wt% or less, and a sulfur content of more than 0.5 wt%, preferably 0.8 wt% to 1.5 wt%.

[0043] According to one embodiment of the present invention, the first feedstock has an ash content of 0.01 wt% or less, preferably 0.005 wt% or less, and a sulfur content of 0.1 wt% or less, preferably 0.03 wt% or less.

[0044] According to one embodiment of the present invention, the first feedstock is an ethylene tar extract. Preferably, the first feedstock is prepared according to the following steps: (i) extracting ethylene tar with a solvent to obtain an extract phase and a raffinate phase; (ii) removing the solvent from the extraction phase to obtain an aromatic-enriched oil, and then separating the aromatic-enriched oil to obtain a first light oil and the first feedstock (first heavy oil);

[0045] According to one embodiment of the present invention, the solvent is selected from C3-C12 linear alkanes or cycloalkanes, preferably C5-C12 linear alkanes.

[0046] According to one embodiment of the present invention, the mass ratio of the ethylene tar to the solvent is 1:0.5 to 1:5, preferably 1:1 to 1:2.

[0047] According to one embodiment of the present invention, the extraction is carried out in an extraction unit. For this purpose, the extraction unit comprises at least one extraction column. The extraction unit is operated at a temperature of 30°C to 110°C, preferably 40°C to 80°C. Preferably, the ethylene tar and the solvent are contacted and mass-transferred countercurrently.

[0048] According to one embodiment of the present invention, the regenerated solvent is returned to the extraction unit for recycling.

[0049] According to one embodiment of the present invention, the first heavy oil has a 5% distillation temperature of 300°C to 400°C, preferably 340°C to 380°C.

[0050] According to one embodiment of the present invention, the first light oil has a 95% distillation temperature of 280°C to 400°C (preferably 335°C to 380°C).

[0051] According to one embodiment of the present invention, the first light oil is subjected to a condensation reaction to obtain a condensation product, and then the condensation product is used to produce petroleum coke (low sulfur petroleum coke).

[0052] According to one embodiment of the present invention, prior to cracking, the hydrogenated product is separated to obtain light components (gas, naphtha, etc.) and hydrogenated tail oil, and then the hydrogenated tail oil is cracked to obtain cracked products.

[0053] According to one embodiment of the present invention, alumina is used as a support for the hydrogenation catalyst, and one or several combinations of oxides of Group VIB metals and / or Group VIII metals, such as oxides of metals such as Mo, W, Co, and Ni, are supported thereon as active components. The hydrogenation catalyst can be prepared by existing methods in the art, and existing commercially available catalysts, such as the FZC series and / or FH series hydrogenation catalysts developed by SINOPEC's Dalian Petrochemical Research Institute, can also be used.

[0054] According to one embodiment of the present invention, the operating conditions of the hydrocracking are: a reaction temperature of 310°C to 450°C, preferably 340°C to 390°C; a reaction pressure of 2 MPa to 20 MPa, preferably 4 MPa to 8 MPa; a hydrogen / oil volume ratio of 100 to 2500, preferably 800 to 1800; and -1 ~2.0h -1 , preferably 0.6h -1 ~1.2h -1 Includes the volume LHSV.

[0055] According to one embodiment of the present invention, the hydrogenated tail oil has a 5% distillation temperature of 160°C to 250°C, preferably 180°C to 210°C.

[0056] According to one embodiment of the present invention, the hydrogenated tail oil has a sulfur content of 0.4 wt% or less (preferably 0.35 wt% or less).

[0057] According to one embodiment of the present invention, before being used to produce needle coke, the cracked products are separated to produce a second light oil, a middle distillate oil, and a second heavy oil, and then the middle distillate oil is used as a starting material to produce needle coke.

[0058] According to one embodiment of the present invention, the decomposition reaction unit includes at least one reactor, and the type of the reactor may be any one of a tubular reactor, a column reactor, and a tank reactor, or a combination thereof, and is preferably a column reactor.

[0059] According to one embodiment of the present invention, the carrier gas may be one or more of water vapor, nitrogen gas, and an inert gas (eg, helium gas, neon gas, argon gas, etc.), and is preferably water vapor.

[0060] According to one embodiment of the present invention, the operating conditions for the cracking include: a reaction temperature of 380°C to 520°C, preferably 420°C to 490°C; a reaction pressure of 0.1MPa to 5MPa, preferably 0.2MPa to 1.0MPa; a residence time of 0.01h to 30h, preferably 0.1h to 3h; and an oil to steam mass ratio of 100:0.1 to 100:20, preferably 100:1 to 100:8.

[0061] According to one embodiment of the present invention, the middle distillate oil has a distillation range of 330°C to 530°C (preferably 350°C to 500°C).

[0062] According to one embodiment of the present invention, the second light oil has a 95% distillation temperature of 300°C to 400°C (preferably 320°C to 380°C). Correspondingly, the second heavy oil has a 5% distillation temperature of 460°C to 550°C (preferably 485°C to 510°C).

[0063] According to one embodiment of the present invention, at least a portion of the second light oil is recycled back to the hydrotreatment.

[0064] According to one embodiment of the present invention, at least a portion of the second light oil is subjected to a condensation reaction to produce a condensation product, and then the condensation product is used to produce petroleum coke (low sulfur petroleum coke).

[0065] According to one embodiment of the present invention, a portion of the second light oil is recycled back to the hydrotreatment, and another portion is subjected to a condensation reaction.

[0066] According to one embodiment of the present invention, the raffinate phase is mixed with the second heavy oil, and the resulting mixture is then used to produce petroleum coke (low sulfur petroleum coke).

[0067] According to one embodiment of the present invention, the mass ratio of the raffinate phase to the second heavy oil is 1:1 to 0.01:1 (preferably 0.5:1 to 0.1:1).

[0068] According to one embodiment of the present invention, the low sulfur petroleum coke production comprises at least one heater furnace, two coke drums and one coke fractionator, at least one of the coke drums being in a reaction stage at any one time and at least one being in a purge and decoking stage.

[0069] According to one embodiment of the present invention, the operating conditions for producing petroleum coke include: a furnace outlet temperature of 440°C-550°C, preferably 490°C-510°C, a coke drum top pressure of 0.01 MPa-2.5 MPa, preferably 0.1 MPa-0.5 MPa, and a reaction time of 10 h-48 h, preferably 18 h-30 h. The operation can be at constant pressure or variable pressure, preferably at constant pressure.

[0070] According to one embodiment of the present invention, the needle coke production comprises at least one furnace, two coke drums, and one coke fractionator, at least one of which is always in the reaction stage and at least one of which is always in the purge and decoking stage.

[0071] According to one embodiment of the present invention, the operating conditions for producing needle coke include a furnace outlet temperature of 420°C to 560°C, preferably 440°C to 530°C, and a heating rate of 0.5°C / h to 30°C / h. The coke drum top pressure is 0.01 MPa to 2.5 MPa, preferably 0.2 MPa to 1.3 MPa. The reactor can be operated at a constant pressure or at a variable pressure. When variable pressure operation is employed, the pressure change rate is 0.1 MPa / h to 5 MPa / h. The reaction time is generally 10 hours to 72 hours, preferably 32 hours to 54 hours.

[0072] According to one embodiment of the present invention, the condensation reaction can be carried out without adding a condensation catalyst or with the addition of a condensation catalyst, preferably with the addition of a condensation catalyst. The condensation catalyst includes a support and an active component. The support is one or more of kaolin, montmorillonite, alumina, and silicon-containing alumina, preferably alumina. The active component is at least one oxide of a metal of Group IVB and / or Group VIB, and the active metal can be selected from at least one of zirconium, tungsten, and molybdenum. Based on the weight of the catalyst, the content of the active component is 0.1 wt% to 50 wt%, preferably 5 wt% to 25 wt%. The shape of the condensation catalyst can be one or more of a sphere, a cylinder, a three-leaf clover, a four-leaf clover, a Raschig ring, etc.

[0073] According to one embodiment of the present invention, the operating conditions for the condensation reaction include: a reaction temperature of 350°C to 530°C, preferably 380°C to 450°C; a reaction pressure of 0.01 MPa to 5 MPa, preferably 1 MPa to 3 MPa; and a residence time of 0.1 h to 15 h, preferably 0.5 h to 6 h.

[0074] According to one embodiment of the present invention, the condensation reaction comprises at least one reactor, preferably a fixed-bed reactor, which comprises at least one feed inlet and one discharge outlet.

[0075] According to one embodiment of the present invention, the present invention also relates to an apparatus for producing needle coke. According to the present invention, the apparatus for producing needle coke is specifically used to realize the above-mentioned method for producing needle coke. Therefore, for the content not described in detail in the section on the apparatus for producing, direct reference can be made to the relevant content described in the overall context of the method for producing.

[0076] According to one embodiment of the present invention, the apparatus for producing needle coke comprises the following units: a feedstock supply unit configured to supply a first feedstock and a second feedstock; a hydrotreating unit configured to hydrotreat the mixture of the first feedstock and the second feedstock to obtain a hydrotreated product; a cracking unit configured to crack the hydrogenation product to obtain a cracked product; a needle coke production unit configured to produce needle coke using the cracking product as a starting material;

[0077] According to one embodiment of the present invention, the apparatus for manufacturing comprises the following units: an extraction unit configured to receive ethylene tar and a solvent, which are processed to produce an extract phase and a raffinate phase; a solvent recovery unit configured to receive the extract phase from the extraction unit, which is separated to produce a regenerated solvent and an aromatic-enriched oil; a first separation unit configured to receive the aromatics-enriched oil from the solvent recovery unit, which is cut to produce a first light oil and a first heavy oil (corresponding to said first feedstock); a hydrogenation reaction unit configured to receive the first feedstock and a catalyst slurry oil (corresponding to the second feedstock), which is subjected to a hydrogenation reaction in the presence of hydrogen gas and a hydrogenation catalyst; a hydroseparation unit configured to receive the hydrogenation product from the hydroreaction unit, which is separated to produce gas, naphtha, and hydrogenated tail oil; a cracking reaction unit configured to receive the hydrogenated tail oil from the hydroseparation unit, the hydrogenated tail oil being subjected to a cracking reaction in the presence of a carrier gas; a second separation unit configured to receive the cracked products from the cracking reaction unit, which are separated to produce a second light oil, a middle distillate oil, and a second heavy oil; and a needle coke production unit configured to receive said middle distillate oil, which reacts to produce needle coke.

[0078] According to one embodiment of the present invention, the extraction unit comprises at least one extraction column. The extraction column is not particularly limited and can be any form of extraction unit currently available in the art. Those skilled in the art can freely select the extraction column according to actual conditions.

[0079] According to one embodiment of the present invention, the present invention includes a condensation reaction unit, which is used to receive the first light oil from the first separation unit. The condensation reaction product is sent to a low-sulfur petroleum coke production unit via a pipeline for processing. The condensation reaction unit includes at least one reactor, preferably a fixed-bed reactor.

[0080] According to one embodiment of the present invention, the regenerated solvent obtained in the solvent recovery unit is returned to the extraction unit via a pipeline for recycling.

[0081] According to one embodiment of the present invention, the hydrogenation reaction unit includes at least one hydrogenation reactor. When two or more hydrogenation reactors are present, the connection between the reactors is not particularly limited, and they are generally connected in series. The reactor may be any one or a combination of a fluidized bed reactor, a floating bed reactor, and a fixed bed reactor, and is preferably a fixed bed reactor.

[0082] According to one embodiment of the present invention, the hydroseparation unit includes a high-temperature high-pressure separator, a low-temperature high-pressure separator, a high-temperature low-pressure separator, and a low-temperature low-pressure separator, and may further include a stripping column, a fractionation column, and the like.

[0083] According to one embodiment of the present invention, the first separation system may be any one or several combinations of a stripping column, a flash column, a fractionation column, etc., and is preferably a fractionation column.

[0084] According to one embodiment of the present invention, the second separation unit may be any one of a stripping column, a flash column, a fractionation column, etc., or some combination thereof, and is preferably a fractionation column.

[0085] According to one embodiment of the present invention, the second light oil obtained from the second separation unit is recycled back to the hydrotreating unit via a pipeline; or sent to a condensation reaction unit to carry out a condensation reaction to produce a condensation product, and the condensation product is sent to a low sulfur petroleum coke production unit to produce low sulfur petroleum coke; or a portion is recycled back to the hydrotreating unit; and the remainder is sent to the condensation reaction unit.

[0086] According to one embodiment of the present invention, a low sulfur petroleum coke production unit comprises at least one heating furnace, two coke drums, and one coke fractionator, at least one of which is always in a reaction stage and at least one of which is always in a purge and decoking stage.

[0087] According to one embodiment of the present invention, the needle coke production unit comprises at least one heating furnace, two coke drums, and one coke fractionator, at least one of which is always in the reaction stage and at least one of which is always in the purge and decoking stage.

[0088] A specific embodiment of the present invention will now be described in detail in conjunction with the accompanying drawings.

[0089] As shown in FIG. 1 , according to the present invention, the ethylene tar 2 is sent to the extraction unit 9 to be contacted with the solvent 14 to produce an extract phase 16 and a raffinate phase 15, and the extract phase 16 is sent to the solvent recovery unit 10 to be separated to produce a recycled solvent 18 and an aromatics-rich oil 17; the recycled solvent 18 is returned to the extraction unit 9 for recycling, and the aromatics-rich oil is sent to the first separation unit 11 to be separated to produce a first light oil 19 and a first heavy oil 20, and the first light oil 19 can be discharged or sent to the condensation reaction unit 5 to undergo a condensation reaction to produce a condensation reaction product 27, and the condensation reaction product 27 is sent together with the raffinate phase 15 to the low-sulfur petroleum coke production unit 8; the first heavy oil 20, the catalyst slurry oil 1 and the hydrogen gas 30 are sent to the hydrogenation reaction unit 3 to undergo a hydrogenation reaction in the presence of a hydrogenation catalyst to produce a hydrogenation product 21, and the hydrogenation product 21 is then hydrogenated. The resulting hydrogenated tail oil 22 is sent to a cracking reaction unit 6 where it is separated to produce gas 28, naphtha 29 and hydrogenated tail oil 22; the resulting hydrogenated tail oil 22 is sent to a cracking reaction unit 6 where it undergoes a cracking reaction in the presence of a carrier gas 7 to produce a cracked product 23, and the cracked product 23 is sent to a second separation unit 12 where it is separated to produce a second light oil 24, a middle distillate oil 25 and a second heavy oil 26; the resulting second heavy oil 26 is sent to a low sulfur petroleum coke production unit 8 to produce low sulfur petroleum coke; the resulting middle distillate oil 25 is sent to a needle coke production unit 13 to produce needle coke; the second light oil 24 can be recycled back to the hydrogenation reaction unit 3 for processing, or can be sent to the condensation reaction unit 5 for processing, or a portion can be recycled to the hydrogenation reaction unit 3 for processing and the remainder can be sent to the condensation reaction unit 5 for processing.

[0090] Example The present invention will be described in more detail below using examples, but the present invention is not limited to these examples.

[0091] The properties of the catalyst slurry oil (second feedstock) and ethylene tar, which are the starting materials for the examples and comparative examples of the present invention, are shown in Table 1. The change in the TI content of the catalyst slurry oil with reaction temperature is shown in Figure 2. The coking onset temperature of the second feedstock is 460°C to 465°C. The extractant used in the extraction unit is n-heptane. The hydrotreating catalyst used is the FZC-34BT hydrotreating catalyst developed by SINOPEC's Dalian Petrochemical Research Institute. The carrier gas used in the cracking treatment unit is steam.

[0092] Example 1 The ethylene tar was sent to an extraction unit to contact with an extractant, and the resulting mixture was separated to produce a raffinate phase and an aromatics-enriched oil. The aromatics-enriched oil was separated to produce a first light oil and a first heavy oil. The first heavy oil was subjected to mild hydrocracking to produce a first feedstock. The catalyst slurry oil and the first feedstock were mixed in a mass ratio of 1:0.1 and sent to a hydrogenation reaction unit. The resulting hydrogenated product was separated to produce a hydrogenated tail oil. The hydrogenated tail oil was sent to a cracking reaction unit. The resulting cracked product was separated to produce a middle distillate oil. The middle distillate oil was sent to a needle coke production unit to produce needle coke. The operating parameters of the extraction unit, hydrogenation reaction unit, cracking reaction unit, and needle coke production unit are shown in Table 2.

[0093] The change in the TI content of the first feedstock as a function of reaction temperature is shown in Figure 3. The coking initiation temperature of the first feedstock was approximately 440°C.

[0094] The properties of the first feedstock are shown in Table 3.

[0095] The properties of needle coke are shown in Table 4.

[0096] Example 2 The ethylene tar was sent to an extraction unit to contact with an extractant, and the resulting mixture was separated to produce a raffinate phase and an aromatics-enriched oil. The aromatics-enriched oil was separated to produce a first light oil and a first heavy oil. The first heavy oil was used as the first feedstock. The catalyst slurry oil and the first feedstock were mixed in a mass ratio of 1:2 and sent to a hydrogenation reaction unit. The resulting hydrogenated product was separated to produce a hydrogenated tail oil. The hydrogenated tail oil was sent to a cracking reaction unit. The resulting cracked product was separated to produce a middle distillate oil. The middle distillate oil was sent to a needle coke production unit to produce needle coke. The operating parameters of the extraction unit, hydrogenation reaction unit, cracking reaction unit, and needle coke production unit are listed in Table 2.

[0097] The change in the TI content of the first feedstock as a function of reaction temperature is shown in Figure 4. The coking initiation temperature of the first feedstock is 400°C to 405°C.

[0098] The properties of the first feedstock are shown in Table 3.

[0099] The properties of needle coke are shown in Table 4.

[0100] The polarized microstructure of the needle coke is shown in Figure 5. The microstructure of the needle coke obtained in Example 2 consists mainly of large flakes with little fibrous structure.

[0101] Example 3 The ethylene tar was sent to an extraction unit to be contacted with an extractant, and the resulting mixture was separated to produce a raffinate phase and an aromatics-enriched oil. The aromatics-enriched oil was separated to produce a first light oil and a first heavy oil. The first heavy oil was used as the first feedstock. The catalyst slurry oil and the first feedstock were mixed in a mass ratio of 1:0.08 and sent to a hydrogenation reaction unit. The resulting hydrogenated product was separated to produce a hydrogenated tail oil. The hydrogenated tail oil was sent to a cracking reaction unit. The resulting cracked products were separated to produce a second light oil, a middle distillate oil, and a second heavy oil. The middle distillate oil was sent to a needle coke production unit to produce needle coke. The operating parameters of the extraction unit, hydrotreating unit, cracking unit, and needle coke production unit are listed in Table 2.

[0102] The raffinate phase obtained from the extraction unit and the second heavy oil from the second separation unit were mixed and sent to a low-sulfur petroleum coke production unit, the operation conditions of which were: furnace outlet temperature: 497°C, coke drum top pressure: 0.45 MPa, and reaction time: 28 hours.

[0103] The properties of the first feedstock are shown in Table 3.

[0104] The change in the TI content of the first feedstock as a function of reaction temperature is shown in Figure 6. The coking initiation temperature of the first feedstock was 405°C to 410°C.

[0105] The properties of needle coke are shown in Table 4.

[0106] The polarizing fiber structure of the needle coke is shown in Figure 7. The texture of the needle coke obtained in Example 3 contained a large amount of fiber structure.

[0107] The sulfur content of low sulfur petroleum coke is shown in Table 5.

[0108] Example 4 This example was carried out in essentially the same manner as in Example 3, except that the first light oil obtained from the first separation unit was sent to a condensation reaction unit, the condensation catalyst support was alumina, the active component was 7.5 wt% ZrO2-3.6 wt% MoO2 with a three-leaf clover structure, and the condensation product obtained from the condensation reaction unit was at a reaction temperature of 426°C, a reaction pressure of 1.3 MPa, and a residence time of 1.5 h. The condensation product was mixed with the raffinate phase obtained from the extraction unit and the second heavy oil obtained from the second separation unit, and the resulting mixture was sent to a low-sulfur petroleum coke production unit.

[0109] The operating parameters of the extraction unit, hydrogenation reaction unit, cracking reaction unit, and needle coke production unit are shown in Table 2.

[0110] The properties of the first feedstock are shown in Table 3.

[0111] The change in the TI content of the first feedstock as a function of reaction temperature is shown in Figure 8. The coking initiation temperature of the first feedstock was 407°C to 410°C.

[0112] The properties of needle coke are shown in Table 4.

[0113] The sulfur content of low sulfur petroleum coke is shown in Table 5.

[0114] Comparative Example 1 The catalyst slurry oil was sent to the hydrogenation reaction unit. The resulting hydrogenated product was separated to produce hydrogenated tail oil. The hydrogenated tail oil was sent to the cracking reaction unit. The resulting cracked product was separated to produce middle distillate oil. The middle distillate oil was sent to the needle coke production unit to produce needle coke. The operating parameters of the hydrogenation reaction unit, cracking reaction unit, and needle coke production unit are shown in Table 6.

[0115] The properties of needle coke are shown in Table 7.

[0116] Comparative Example 2 The ethylene tar was sent to the hydrogenation reaction unit. The resulting hydrogenation product was separated to produce hydrogenated tail oil. The hydrogenated tail oil was sent to the cracking reaction unit. The resulting cracked product was separated to produce middle distillate oil. The middle distillate oil was sent to the needle coke production unit to produce needle coke. The operating parameters of the hydrogenation reaction unit, cracking reaction unit, and needle coke production unit are shown in Table 6.

[0117] The change in the TI content of ethylene tar depending on the reaction temperature is shown in Figure 9. The coking temperature of ethylene tar was 395°C to 397°C. The properties of needle coke are shown in Table 7.

[0118] The polarizing fiber structure of the needle coke is shown in Figure 10. The needle coke obtained in Comparative Example 2 had a poor texture, was mainly large flakes, and had a mixed mosaic structure.

[0119] Comparative Example 3 The catalyst slurry oil and ethylene tar were mixed in a mass ratio of 1:0.1 and sent to a hydrogenation reaction unit. The resulting hydrogenated product was separated to produce hydrogenated tail oil; the hydrogenated tail oil was sent to a needle coke production unit to produce needle coke. The operating parameters of the hydrogenation reaction unit and needle coke production unit are shown in Table 6.

[0120] The properties of needle coke are shown in Table 7.

[0121] The polarizing fiber structure of the needle coke is shown in Figure 11. The needle coke obtained in Comparative Example 3 had a poor texture and contained a large amount of mosaic structure.

[0122] Comparative Example 4 The catalyst slurry oil and ethylene tar were mixed in a mass ratio of 1:0.12 and sent to a cracking reaction unit. The resulting cracked product was separated to produce a middle distillate oil. The middle distillate oil was sent to a needle coke production unit to produce needle coke. The operating parameters of the cracking reaction unit and needle coke production unit are shown in Table 6.

[0123] The properties of needle coke are shown in Table 7.

[0124] Comparative Example 5 The catalyst slurry oil and ethylene tar were mixed in a mass ratio of 1:0.05 and sent directly to the needle coke production unit to produce needle coke. The operating parameters of the needle coke production unit are shown in Table 6.

[0125] The properties of needle coke are shown in Table 7.

[0126] The time-dependent change in the pressure inside the furnace tube of the heating furnace of the needle coke production unit is shown in Figure 12. In the furnace tube of the coke heating furnace of Comparative Example 5, a serious coking phenomenon occurred, and the equipment could not be operated for a long period of time.

[0127] [Table 1] [Table 2] [Table 3] [Table 4] [Table 5] [Table 6] [Table 7]

[0128] Although the Hardgrove grindability index and particle strength of Comparative Examples 4 and 5 were relatively high, the sulfur content exceeded 0.5 wt %, and did not meet the quality index of needle coke.

Claims

1. 1. A method for producing needle coke, comprising the steps of: (1) hydrotreating a mixture of a first feedstock and a second feedstock to obtain a hydrotreated product; (2) cracking the hydrogenated product to obtain a cracked product; (3) producing the needle coke using the cracked product as a starting material, The method of claim 1, wherein the first feedstock has an aromatic carbon percentage greater than 65 mol% (preferably 70 mol% to 95 mol%) and the second feedstock has an aromatic carbon percentage greater than 60 mol% (preferably 70 mol% to 90 mol%), and the coking onset temperature of the first feedstock is 10°C to 140°C, preferably 35°C to 105°C, lower than the coking onset temperature of the second feedstock.

2. 2. The method of claim 1, wherein the weight ratio of the second feedstock to the first feedstock is from 1:1 to 1:0.001 (preferably from 1:0.2 to 1:0.01).

3. 2. The method of claim 1, wherein the first feedstock has a coking onset temperature of 350°C to 420°C, preferably 380°C to 415°C, and the second feedstock has a coking onset temperature of 430°C to 490°C, preferably 450°C to 485°C.

4. 10. The method of claim 1, wherein the second feedstock is a catalyst slurry oil and the first feedstock is an ethylene tar extract.

5. 2. The method of claim 1, wherein the second feedstock has an ash content of 0.01 wt % or less, preferably 0.005 wt % or less, and a sulfur content of more than 0.5 wt %, preferably 0.8 wt % to 1.5 wt %, and the first feedstock has an ash content of 0.01 wt % or less, preferably 0.005 wt % or less, and a sulfur content of 0.1 wt % or less, preferably 0.03 wt % or less.

6. The first feedstock is subjected to the following steps: (i) extracting ethylene tar with a solvent to obtain an extract phase and a raffinate phase; (ii) removing the solvent from the extraction phase to obtain an aromatic-enriched oil, and then separating the aromatic-enriched oil to obtain a first light oil and the first feedstock (i.e., a first heavy oil); 2. The method of claim 1, prepared according to

7. 7. The process according to claim 6, wherein the solvent is selected from C3 to C12 linear alkanes or cycloalkanes, preferably C5 to C12 linear alkanes, and / or the mass ratio of the ethylene tal to the solvent is from 1:0.5 to 1:5, preferably from 1:1 to 1:

2.

8. 7. The method of claim 6, wherein the extraction is carried out at a temperature of from 30°C to 110°C, preferably from 40°C to 80°C.

9. The method according to claim 6, wherein the 5% distillation temperature of the first heavy oil is 300°C to 400°C, preferably 340°C to 380°C.

10. 7. The method according to claim 6, wherein the 95% distillation temperature of the first light oil is 280°C to 400°C (preferably 335°C to 380°C), and / or the first light oil is subjected to a condensation reaction to produce a condensation product, and then the condensation product is used to produce petroleum coke.

11. 11. The process according to claim 10, wherein the operating conditions of the condensation reaction comprise: a reaction temperature of 350°C to 530°C, preferably 380°C to 450°C, a reaction pressure of 0.01 MPa to 5 MPa, preferably 1 MPa to 3 MPa, and a residence time of 0.1h to 15h, preferably 0.5h to 6h.

12. 2. The method of claim 1, wherein, prior to the cracking, the hydrogenated product is separated to obtain light components (gas, naphtha, etc.) and hydrogenated tail oil, and then the hydrogenated tail oil is cracked to obtain the cracked product.

13. The operating conditions of the hydrotreating are: a reaction temperature of 310°C to 450°C, preferably 340°C to 390°C; a reaction pressure of 2 MPa to 20 MPa, preferably 4 MPa to 8 MPa; a hydrogen / oil volume ratio of 100 to 2500, preferably 800 to 1800; －１ ~2.0h －１ , preferably 0.6 h －１ ~1.2 hours －１ The method of claim 1 , wherein the LHSV is a volume of

14. 13. The method of claim 12, wherein the hydrogenated tail oil has a 5% distillation temperature of 160°C to 250°C, preferably 180°C to 210°C, and / or the hydrogenated tail oil has a sulfur content of 0.4 wt% or less (preferably 0.35 wt% or less).

15. 10. The method of claim 1, wherein the cracked products are separated to produce a second light oil, a middle distillate oil, and a second heavy oil before being used to produce the needle coke, and then the middle distillate oil is used as a starting material to produce the needle coke.

16. 16. The process according to claim 15, wherein the operating conditions of the cracking comprise: a reaction temperature of 380°C to 520°C, preferably 420°C to 490°C; a reaction pressure of 0.1 MPa to 5 MPa, preferably 0.2 MPa to 1.0 MPa; a residence time of 0.01h to 30h, preferably 0.1h to 3h; an oil to steam volume ratio of 100:0.1 to 100:20, preferably 100:1 to 100:

8.

17. 16. The method of claim 15, wherein the middle distillate oil has a distillation range of 330°C to 530°C (preferably 350°C to 500°C).

18. The method according to claim 15, wherein the 95% distillation temperature of the second light oil is 300°C to 400°C (preferably 320°C to 380°C), and the 5% distillation temperature of the second heavy oil is 460°C to 550°C (preferably 485°C to 510°C).

19. 16. The method of claim 15, wherein at least a portion of the second light oil is recycled back to the hydrotreating; or at least a portion of the second light oil is subjected to a condensation reaction to produce a condensation product, and then the condensation product is used to produce petroleum coke; or a portion of the second light oil is recycled back to the hydrotreating and the remainder is subjected to the condensation reaction.

20. 7. The method of claim 6, wherein after mixing the raffinate phase with the second heavy oil, the resulting mixture is used to produce petroleum coke, and / or the mass ratio of the raffinate phase to the second heavy oil is from 1:1 to 0.01:1 (preferably from 0.5:1 to 0.1:1).

21. 21. The method according to claim 10 or 20, wherein the operating conditions for producing the petroleum coke comprise: a heater outlet temperature of 440°C to 550°C, preferably 490°C to 510°C, a coke drum top pressure of 0.01 MPa to 2.5 MPa, preferably 0.1 MPa to 0.5 MPa, and a reaction time of 10h to 48h, preferably 18h to 30h.

22. 2. The method of claim 1, wherein the operating conditions for producing the needle coke comprise: a heater outlet temperature of 420°C to 560°C, preferably 440°C to 530°C, a coke drum top pressure of 0.01 MPa to 2.5 MPa, preferably 0.2 MPa to 1.3 MPa, and a reaction time of 10 h to 72 h, preferably 32 h to 54 h.

23. 1. An apparatus for producing needle coke, comprising the following units: a feedstock supply unit configured to supply a first feedstock and a second feedstock; a hydrotreating unit configured to hydrotreat a mixture of the first feedstock and the second feedstock to obtain a hydrotreated product; a cracking unit configured to crack the hydrogenation product to obtain a cracked product; a needle coke production unit configured to produce the needle coke using the cracked product as a starting material, The first feedstock has an aromatic carbon ratio of greater than 65 mol% (preferably 70 mol% to 95 mol%), and the second feedstock has an aromatic carbon ratio of greater than 60 mol% (preferably 70 mol% to 90 mol%), and the coking onset temperature of the first feedstock is 10°C to 140°C, preferably 35°C to 105°C, lower than the coking onset temperature of the second feedstock.

24. The following units: an extraction unit configured to receive the ethylene tar and the solvent and then process them to produce an extract phase and a raffinate phase; a solvent recovery unit configured to receive the extract phase from the extraction unit and then separate it to produce recycled solvent and an aromatic-enriched oil; a first separation unit configured to receive the aromatics-enriched oil from the solvent recovery unit and then cut it to produce a first light oil and a first heavy oil (corresponding to the first feedstock); a hydrogenation reaction unit configured to receive the first feedstock oil and the catalyst slurry oil (corresponding to the second feedstock oil) and then subject them to a hydrogenation reaction in the presence of hydrogen gas and a hydrogenation catalyst; a hydroseparation unit configured to receive and separate the hydrogenated product from the hydrogenation reaction unit to produce gas, naphtha, and hydrogenated tail oil; a cracking reaction unit configured to receive the hydrogenated tail oil from the hydroseparation unit and then subject the hydrogenated tail oil to a cracking reaction in the presence of a carrier gas; a second separation unit configured to receive the cracked product from the cracking reaction unit and separate it to produce a second light oil, a middle distillate oil, and a second heavy oil; and 24. The apparatus of claim 23, comprising a needle coke production unit configured to receive the middle distillate oil and then react it to produce the needle coke.

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