A method and apparatus for producing needle coke using mixed feedstock oil

Abstract

The present invention relates to a method and an apparatus for producing needle coke using a mixture of raw oils. According to the present invention, needle coke having excellent mechanical properties can be produced. The method for producing needle coke according to the present invention comprises the steps of: (1) hydrotreating a mixture of a first raw oil and a second raw oil 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 raw material, wherein the first raw oil has an aromatic carbon ratio of greater than 65 mol%, the second raw oil has an aromatic carbon ratio of greater than 60 mol%, and the coking onset temperature of the first raw oil is 10-140°C lower than the coking onset temperature of the second raw oil.

Description

Technical Field

[0001] This invention belongs to the field of petrochemical technology, and in particular relates to a method and apparatus for manufacturing needle coke using mixed feedstock oils. Background Technology

[0002] Aromatic oils are high-quality raw materials for the production of needle coke. Catalytic slurry oil and ethylene tar are the preferred materials for producing oil-based needle coke. However, both have certain problems in actual production. Catalytic slurry oil requires desolidification and hydrodesulfurization treatment due to its high ash and sulfur content. Ethylene tar, on the other hand, usually requires degumming treatment due to its high gum content.

[0003] CN110511785A discloses a method for preparing needle coke feedstock from catalytic slurry oil. The specific steps are as follows: first, low-molecular-weight n-alkanes are added to the slurry oil for deasphalting to obtain a supernatant. The supernatant oil is then subjected to extraction and desolidification to obtain an aromatic oil. This aromatic oil is then subjected to hydrodesulfurization treatment to obtain the needle coke feedstock. This method employs an extraction-hydrogenation combined process to desolidify and desulfurize the catalytic slurry oil, ensuring it meets the requirements for use as a needle coke feedstock.

[0004] CN103102974A discloses a method for producing clean fuel oil from ethylene tar. The method involves separating ethylene tar into light and heavy fractions, mixing the heavy fraction with conventional coking feedstock, and then subjecting the mixture to delayed coking to obtain coking gasoline and coking diesel. The coking gasoline undergoes hydrorefining, and the coking diesel is mixed with the light fraction of ethylene tar and subjected to hydrotreating to obtain clean gasoline and diesel products. This method selects appropriate processing methods based on the characteristics of each fraction of ethylene tar, thereby improving the yield of light fuel oil.

[0005] During hydrodesulfurization of catalytic slurry oil, some carbon-carbon double bonds of aromatic rings become saturated and transformed into alkyl side chains. These aromatics with alkyl side chains act as hydrogen donors during needle coke production, hindering molecular polymerization to form large molecules, resulting in incomplete development of the mesophase and affecting the performance of needle coke products. Meanwhile, ethylene tar contains aromatic olefins with poor thermal stability, easily condensing into coke under high-temperature conditions, affecting the long-term operation of the coking unit. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention provides a method and apparatus for manufacturing needle coke using mixed feedstock oils. This method can effectively solve the problem of poor needle coke quality caused by hydrotreating of catalytic oil slurry, as well as the problem of short start-up cycles of delayed coking units due to the poor thermal stability of ethylene tar.

[0007] Specifically, in a first aspect, the present invention relates to a method for manufacturing needle coke, comprising the following steps:

[0008] (1) Hydrotreating a mixture of the first feedstock oil and the second feedstock oil to obtain a hydrogenated product;

[0009] (2) Cracking the hydrogenation product to obtain the cracked product;

[0010] (3) Using the cracking products as raw materials to manufacture needle coke,

[0011] The first feedstock oil has an aromatic carbon content greater than 65 mol% (preferably 70 mol%-95 mol%), the second feedstock oil has an aromatic carbon content greater than 60 mol% (preferably 70 mol%-90 mol%), and the coking initiation temperature of the first feedstock oil is 10-140°C lower than that of the second feedstock oil, preferably 35-105°C lower.

[0012] Furthermore, in a second aspect, the present invention relates to an apparatus for manufacturing needle coke, comprising the following units:

[0013] The feedstock supply unit is configured to provide a first feedstock and a second feedstock.

[0014] Hydrogenation unit: configured to hydrogenate a mixture of the first feedstock oil and the second feedstock oil to obtain a hydrogenated product;

[0015] Cracking unit: configured to crack the hydrogenation products to obtain cracked products;

[0016] Needle coke production unit: configured to manufacture needle coke using the cracking products as raw materials.

[0017] The first feedstock oil has an aromatic carbon content greater than 65 mol% (preferably 70 mol%-95 mol%), the second feedstock oil has an aromatic carbon content greater than 60 mol% (preferably 70 mol%-90 mol%), and the coking initiation temperature of the first feedstock oil is 10-140°C lower than that of the second feedstock oil, preferably 35-105°C lower.

[0018] Technical effect

[0019] Compared with the prior art, the method and apparatus for manufacturing needle coke using mixed feedstock oils provided by the present invention have one or more or a combination of the following advantages:

[0020] (1) According to the present invention, in a preferred embodiment, ethylene tar is first subjected to an extraction unit to remove gum / asphaltite to obtain aromatic oil, which is then divided into first light oil and first heavy oil according to the distillation range. The first light oil is rich in bicyclic aromatics. The first heavy oil is rich in tricyclic and higher aromatics. The first heavy oil is a high-quality raw material for preparing needle coke. The condensation product obtained after the condensation reaction of the first light oil is mixed with the raffinate phase rich in gum / asphaltite obtained from the extraction unit to prepare low-sulfur petroleum coke. The addition of the condensation product can improve the dispersion of gum / asphaltite in the raffinate phase, prevent it from precipitating and coking in the heating furnace, and improve the quality and yield of low-sulfur petroleum coke.

[0021] (2) According to the present invention, in a preferred embodiment, the catalytic slurry is mixed with the first heavy oil and enters the hydrogenation reaction unit. Since the first heavy oil (derived from ethylene tar) contains aromatic olefins, the carbon-carbon double bonds of olefins are easier to hydrogenate than the carbon-carbon double bonds of aromatic rings. Therefore, in the hydrogenation reaction unit, the carbon-carbon double bond saturation reaction of the first heavy oil olefins occurs first, followed by the hydrogenation desulfurization reaction of the catalytic slurry, and finally the carbon-carbon double bond saturation reaction of aromatics. Due to the existence of competing reactions, the aromatic ring saturation rate of the catalytic slurry can be effectively reduced, avoiding the generation of too many aromatics with a large number of alkyl side chains or cycloalkyl side chains, which would cause a decrease in the number of aromatic rings and affect the mechanical properties of needle coke.

[0022] (3) According to the present invention, in a preferred embodiment, the hydrotreated tail oil is sent to the cracking reaction unit to break the side chains of the aromatics saturated during the hydrotreating process, and the molecules are reconstituted into aromatic structures with short side chains. The separated middle distillate oil (containing tricyclic and tetracyclic aromatics) is more suitable as a feedstock for needle coke production. The second light oil is a cracking product, rich in small molecule hydrocarbons. If it is returned to the hydrotreating unit, the naphtha yield can be increased. If the second light oil is sent to the low-sulfur petroleum coke production unit after condensation, it will continue to undergo deep condensation to generate low-sulfur petroleum coke, thereby improving the utilization value of the oil products.

[0023] (4) According to the present invention, in a preferred embodiment, after separating the fraction rich in tricyclic and tetracyclic aromatics for the production of needle coke, the remaining fraction, being rich in aromatics or gums / asphalt and having a very low sulfur content, is a high-quality raw material for the production of low-sulfur petroleum coke. The present invention utilizes the components in the raw material in a graded manner, which greatly improves the effective utilization rate of catalytic slurry and ethylene tar. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the process for manufacturing needle coke using mixed feedstock oils provided by the present invention.

[0025] Figure 2 The trend of TI content in the catalyst slurry used in the examples and comparative examples as a function of reaction temperature.

[0026] Figure 3The trend of TI content in the first feedstock oil used in Example 1 as a function of reaction temperature.

[0027] Figure 4 The trend of TI content in the first feedstock oil used in Example 2 as a function of reaction temperature.

[0028] Figure 5 This is a polarized micrograph of the needle focal length obtained in Example 2.

[0029] Figure 6 The trend of TI content in the first feedstock oil used in Example 3 as a function of reaction temperature.

[0030] Figure 7 This is a polarized micrograph of the needle-shaped focal plane obtained in Example 3.

[0031] Figure 8 The trend of TI content in the first feedstock oil used in Example 4 as a function of reaction temperature.

[0032] Figure 9 The trend of TI content in the ethylene tar used in Comparative Example 2 as a function of reaction temperature.

[0033] Figure 10 This is a polarized micrograph of the needle focal length obtained in Comparative Example 2.

[0034] Figure 11 This is a polarized micrograph of the needle focal length obtained in Comparative Example 3.

[0035] Figure 12 The trend of furnace tube pressure change over time in the heating furnace of the needle coke production unit (Comparative Example 5) is shown. Detailed Implementation

[0036] The specific embodiments of the present invention will be described in detail below. However, it should be noted that the scope of protection of the present invention is not limited to these specific embodiments, but is determined by the claims in the appendix.

[0037] All publications, patent applications, patents, and other references mentioned in this specification are incorporated herein by reference. Unless otherwise defined, all technical and scientific terms used in this specification have the meanings commonly understood by those skilled in the art. In case of conflict, the definitions in this specification shall prevail.

[0038] When this specification uses the prefixes “known to those skilled in the art,” “prior art,” or similar terms to derive materials, substances, methods, steps, apparatus, or components, the objects derived from such prefixes cover those commonly used in the art at the time of this application’s filing, but also include those that are not currently commonly used but will become generally recognized in the art as suitable for similar purposes.

[0039] Unless otherwise expressly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "comprises" shall be understood to include the stated elements or components without excluding other elements or other components.

[0040] In the context of this specification, for ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” “above,” “upper,” etc., may be used to describe the relationship of one element or feature to another element or feature in the accompanying drawings. It should be understood that spatial relative terms are intended to encompass different orientations of an object in use or operation, other than those depicted in the figures. For example, if an object in the figure is flipped, an element described as “below” or “under” another element or feature would be oriented “above” said element or feature. Thus, the exemplary term “below” can encompass both the downward and upward orientations. An object may also have other orientations (e.g., rotated 90 degrees or other orientations), and the spatial relative terms used herein should be interpreted accordingly.

[0041] In the context of this specification, the terms "first," "second," etc., are used to distinguish two different elements or parts, and are not used to define a specific position or relative relationship.

[0042] In the context of this specification, all numeric values ​​of parameters (e.g., quantities or conditions) should be understood to be modified by the term “about” in all cases, regardless of whether “about” actually appears before the numeric value.

[0043] In the context of this specification, catalytic slurry refers to heavy distillate oil produced by catalytic cracking.

[0044] In the context of this specification, ethylene tar refers to heavy distillate oil produced by an ethylene cracking unit.

[0045] In the context of this specification, the sulfur content of coke is determined by the GB / T 24526 method.

[0046] In the context of this specification, the Hastelloy grindability index of coke is determined by the GB / T 2565 method.

[0047] In the context of this specification, the strength of coke particles is determined by the method in Appendix B of T / ZGTS 002.

[0048] In the context of this specification, the ash content of coke is determined by the GB / T 1429 method.

[0049] In the context of this specification, the ash content of the oil is determined by the GB / T 508 method.

[0050] In the context of this specification, the sulfur content of the oil is determined by the SH / T0689 method.

[0051] In the context of this specification, the aromatic carbon content of the oil is determined by the SH / T0793 method.

[0052] In the context of this specification, the method for measuring the coking initiation temperature is as follows: after the feedstock oil has been allowed to stand at a certain temperature for 20 minutes, the content of toluene-insoluble matter (TI) is analyzed. When the TI content is higher than 0.5 wt%, the feedstock oil is considered to have begun to coke, and the temperature at this point is the coking initiation temperature of the feedstock oil.

[0053] Unless otherwise specified, all percentages, parts, ratios, etc. mentioned in this instruction manual are based on weight, and the pressure is gauge pressure.

[0054] In the context of this specification, any two or more embodiments of the present invention can be arbitrarily combined, and the resulting technical solutions are part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0055] According to one embodiment of the present invention, a method for manufacturing needle coke is provided. According to the present invention, the method for manufacturing needle coke is performed in a needle coke manufacturing apparatus described below. Therefore, for details not described in the manufacturing method section, reference can be made directly to the relevant content described below regarding the manufacturing apparatus.

[0056] According to one embodiment of the present invention, the method for manufacturing the needle coke includes the following steps:

[0057] (1) Hydrotreating a mixture of the first feedstock oil and the second feedstock oil to obtain a hydrogenated product;

[0058] (2) Cracking the hydrogenation product to obtain the cracked product;

[0059] (3) Using the cracking products as raw materials to manufacture needle coke.

[0060] According to one embodiment of the present invention, the aromatic carbon content of the first feedstock oil is greater than 65 mol% (preferably 70 mol%-95 mol%). If the aromatic carbon content is too low, it indicates that the aromatic hydrocarbon content is low or that the aromatic ring contains many side chains. After hydrogenation, the aromatic carbon content will be further reduced, making it unsuitable as a feedstock for the production of needle coke.

[0061] According to one embodiment of the present invention, the aromatic carbon content of the second feedstock oil is greater than 60 mol% (preferably 70 mol%-90 mol%). If the aromatic carbon content is too low, it indicates that the aromatic hydrocarbon content is low or that the aromatic ring contains many side chains. After hydrogenation, the aromatic carbon content will be further reduced, making it unsuitable as a feedstock for the production of needle coke.

[0062] According to one embodiment of the present invention, the coking initiation temperature of the first feedstock oil is 10-140°C lower than that of the second feedstock oil, preferably 35-105°C lower. If the coking initiation temperature of the first feedstock is too low, coking is likely to occur in the hydrotreating reactor, and the reaction cannot continue; if the coking initiation temperature of the first feedstock is too high, or is comparable to that of the second feedstock, the hydrotreating saturation capacity of the first and second feedstocks may be comparable in the hydrotreating system, which may not alleviate the aromatic ring saturation of the second feedstock, resulting in an excessive reduction in the aromatic carbon content after hydrotreating of the second feedstock.

[0063] According to one embodiment of the present invention, the weight ratio of the second raw material oil to the first raw material oil is 1:1 to 1:0.001 (preferably 1:0.2 to 1:0.01).

[0064] According to one embodiment of the present invention, the coking initiation temperature of the first feedstock oil is 350℃-420℃, preferably 380℃-415℃.

[0065] According to one embodiment of the present invention, the coking initiation temperature of the second feedstock oil is 430℃-490℃, preferably 450℃-485℃.

[0066] According to one embodiment of the present invention, the second feedstock oil is a catalytic oil slurry. Generally, the ash content of the catalytic oil slurry can meet the above requirements after desolidification treatment. The desolidification treatment can be carried out by one or a combination of several methods such as filtration, centrifugal sedimentation, flocculation sedimentation, and electrostatic adsorption, with filtration being preferred.

[0067] According to one embodiment of the present invention, the ash content of the second raw material oil is not higher than 0.01 wt%, preferably not higher than 0.005 wt%, and the sulfur content is higher than 0.5 wt%, preferably 0.8 wt%-1.5 wt%.

[0068] According to one embodiment of the present invention, the ash content of the first raw material oil is not higher than 0.01 wt%, preferably not higher than 0.005 wt%, and the sulfur content is not higher than 0.1 wt%, preferably not higher than 0.03 wt%.

[0069] According to one embodiment of the present invention, the first feedstock oil is an ethylene tar extract. Preferably, the first feedstock oil is manufactured according to the following steps:

[0070] (i) Extract ethylene tar with a solvent to obtain an extract phase and a raffinate phase;

[0071] (ii) The solvent is removed from the extraction phase to obtain an aromatic oil, and then the aromatic oil is separated to obtain a first light oil and a first feedstock oil (first heavy oil).

[0072] According to one embodiment of the present invention, the solvent is selected from C3-C. 12 n-Alkanes or cycloalkanes, preferably selected from C5-C64. 12 n-Alkanes.

[0073] According to one embodiment of the present invention, the mass ratio of the ethylene tar to the solvent is 1:0.5-1:5, preferably 1:1-1:2.

[0074] According to one embodiment of the invention, the extraction is carried out in an extraction unit. For this purpose, the extraction unit includes at least one extraction tower. The operating temperature of the extraction unit is 30°C-110°C, preferably 40°C-80°C. Preferably, the ethylene tar and the solvent are in countercurrent contact and undergo mass transfer.

[0075] According to one embodiment of the present invention, the regenerated solvent is returned to the extraction unit for reuse.

[0076] According to one embodiment of the present invention, the 5% distillation temperature of the first heavy oil is 300°C-400°C, preferably 340°C-380°C.

[0077] According to one embodiment of the present invention, the 95% distillation temperature of the first light oil is 280°C-400°C (preferably 335°C-380°C).

[0078] 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 manufacture petroleum coke (low-sulfur petroleum coke).

[0079] According to one embodiment of the present invention, prior to the cracking, the hydrogenation product is separated to obtain light components (such as gas, naphtha) and hydrogenation tail oil, and then the hydrogenation tail oil is cracked to obtain the cracking product.

[0080] According to one embodiment of the present invention, the hydrogenation catalyst uses alumina as a support and supports oxides of Group VIB and / or Group VIII metals as active components, such as oxides of Mo, W, Co, Ni, etc., or a combination thereof. The hydrogenation catalyst can be prepared using methods existing in the art, or using existing commercial catalysts, such as the FZC and / or FH series hydrogenation catalysts developed by the Dalian Research Institute of Petrochemical Technology, Sinopec.

[0081] According to one embodiment of the present invention, the operating conditions for the hydrotreating include: a reaction temperature of 310℃-450℃, preferably 340℃-390℃; a reaction pressure of 2MPa-20MPa, preferably 4MPa-8MPa; a hydrogen-to-oil volume ratio of 100-2500, preferably 800-1800; and a liquid hourly space velocity of 0.1 h⁻¹. -1 -2.0h -1 Preferably 0.6h -1 -1.2h -1 .

[0082] According to one embodiment of the present invention, the 5% distillation temperature of the hydrotreated tail oil is 160°C-250°C, preferably 180°C-210°C.

[0083] According to one embodiment of the present invention, the sulfur content of the hydrotreated tail oil is not higher than 0.4 wt% (preferably not higher than 0.35 wt%).

[0084] According to one embodiment of the present invention, before being used to manufacture the needle coke, the cracking products are separated to obtain a second light oil, a middle distillate oil, and a second heavy oil, and then the needle coke is manufactured using the middle distillate oil as a raw material.

[0085] According to one embodiment of the present invention, the cracking reaction unit is provided with at least one reactor, which may be one or a combination of tubular reactor, tower reactor, and tank reactor, preferably a tower reactor.

[0086] According to one embodiment of the present invention, the carrier gas may be one or more of water vapor, nitrogen, and inert gases (such as helium, neon, argon, etc.), preferably water vapor.

[0087] According to one embodiment of the present invention, the cracking operating conditions include: a reaction temperature of 380℃-520℃, preferably 420℃-490℃; a reaction pressure of 0.1MPa-5MPa, preferably 0.2MPa-1.0MPa; a residence time of 0.01h-30h, preferably 0.1h-3h; and an oil-gas mass ratio of 100:0.1-100:20, preferably 100:1-100:8.

[0088] According to one embodiment of the present invention, the distillation range of the middle distillate oil is 330℃-530℃ (preferably 350℃-500℃).

[0089] According to one embodiment of the present invention, the 95% distillation temperature of the second light oil is 300°C-400°C (preferably 320°C-380°C). Correspondingly, the 5% distillation temperature of the second heavy oil is 460°C-550°C (preferably 485°C-510°C).

[0090] According to one embodiment of the invention, at least a portion of the second light oil is recycled back to the hydrotreating process.

[0091] According to one embodiment of the present invention, at least a portion of the second light oil is subjected to a condensation reaction to obtain a condensation product, and then the condensation product is used to manufacture petroleum coke (low-sulfur petroleum coke).

[0092] According to one embodiment of the invention, a portion of the second light oil is recycled back to the hydrotreating process, while the other portion undergoes the condensation reaction.

[0093] According to one embodiment of the invention, the raffinate phase and the second heavy oil are mixed, and the resulting mixture is then used to manufacture petroleum coke (low-sulfur petroleum coke).

[0094] According to one embodiment of the present invention, the mass ratio of the raffinate phase to the second heavy oil is 1:1-0.01:1 (preferably 0.5:1-0.1:1).

[0095] According to one embodiment of the present invention, the low-sulfur petroleum coke production includes at least one heating furnace, two coke towers, and one coking fractionation tower. At least one coke tower is always in the reaction stage, and at least one is in the purging and decoking stage.

[0096] According to one embodiment of the present invention, the operating conditions for manufacturing petroleum coke include: a furnace outlet temperature of 440℃-550℃, preferably 490℃-510℃; a coke tower top pressure of 0.01MPa-2.5MPa, preferably 0.1MPa-0.5MPa; and a reaction cycle of 10h-48h, preferably 18h-30h. The operation can be constant pressure or variable pressure, with constant pressure operation being preferred.

[0097] According to one embodiment of the invention, the needle coke manufacturing process includes at least one heating furnace, two coke towers, and one coking fractionation tower. At least one coke tower is always in the reaction stage, and at least one is in the purging and decoking stage.

[0098] According to one embodiment of the present invention, the operating conditions for manufacturing needle coke include: a furnace outlet temperature of 420℃-560℃, preferably 440℃-530℃, and a heating rate of 0.5℃ / h-30℃ / h. The coke tower top pressure is 0.01MPa-2.5MPa, preferably 0.2MPa-1.3MPa. Constant pressure operation or variable pressure operation can be used; if variable pressure operation is adopted, the variable pressure rate is 0.1MPa / h-5MPa / h. The reaction cycle is generally 10h-72h, preferably 32h-54h.

[0099] According to one embodiment of the present invention, the condensation reaction may or may not involve the addition of a condensation catalyst, but is preferably carried out with the addition of a condensation catalyst. The condensation catalyst comprises a support and an active component, wherein the support is one or more of kaolin, montmorillonite, alumina, and silica-containing alumina, preferably alumina; the active component is at least one oxide of a Group IVB and / or Group VIB metal, and the active metal may 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 0.1wt%-50wt%, preferably 5wt%-25wt%. The condensation catalyst may have one or more shapes such as spheres, cylinders, cloverleaf shapes, four-leaf cloverleaf shapes, or Raschig rings.

[0100] According to one embodiment of the present invention, the operating conditions of the condensation reaction include: a reaction temperature of 350℃-530℃, preferably 380℃-450℃, a reaction pressure of 0.01MPa-5MPa, preferably 1MPa-3MPa, and a residence time of 0.1h-15h, preferably 0.5h-6h.

[0101] According to one embodiment of the invention, the condensation reaction is provided with at least one reactor, preferably a fixed-bed reactor, the fixed-bed reactor having at least one inlet and one outlet.

[0102] According to one embodiment of the present invention, an apparatus for manufacturing needle coke is also provided. According to the present invention, the apparatus for manufacturing needle coke is specifically designed for carrying out the needle coke manufacturing method described above. Therefore, for details not described in the section on the manufacturing apparatus, please refer directly to the relevant content described in the entire text regarding the manufacturing method.

[0103] According to one embodiment of the present invention, the needle coke manufacturing apparatus includes the following units:

[0104] The feedstock supply unit is configured to provide a first feedstock and a second feedstock.

[0105] Hydrogenation unit: configured to hydrogenate a mixture of the first feedstock oil and the second feedstock oil to obtain a hydrogenated product;

[0106] Cracking unit: configured to crack the hydrogenation products to obtain cracked products;

[0107] Needle coke production unit: configured to manufacture needle coke using the cracking products as raw materials.

[0108] According to one embodiment of the present invention, the manufacturing apparatus includes the following units:

[0109] Extraction unit: configured to receive ethylene tar and solvent, and after processing, obtain extract phase and raffinate phase;

[0110] Solvent recovery unit: configured to receive the extract phase from the extraction unit, and after separation, obtain regenerated solvent and aromatic oil;

[0111] First separation unit: configured to receive aromatic oil from solvent recovery unit, and cut it to obtain first light oil and first heavy oil (corresponding to the first feedstock oil).

[0112] Hydrogenation reaction unit: configured to receive the first feedstock oil and catalytic slurry (corresponding to the second feedstock oil), and to carry out a hydrogenation reaction under the action of hydrogen and a hydrogenation catalyst;

[0113] Hydrogenation separation unit: configured to receive hydrogenation products from the hydrogenation reaction unit, and separate them to obtain gas, naphtha and hydrogenation tail oil;

[0114] Cracking reaction unit: It is configured to receive hydrotreated tail oil from the hydrodegassing unit and undergo cracking reaction under the action of carrier gas;

[0115] The second separation unit is configured to receive cracking products from the cracking reaction unit and separate them to obtain second light oil, middle distillate oil and second heavy oil.

[0116] Needle coke production unit: configured to receive the intermediate distillate oil and react it to obtain needle coke.

[0117] According to one embodiment of the present invention, the extraction unit includes at least one extraction tower, which can be any type of extraction equipment existing in the art, without any particular limitation, and those skilled in the art can freely choose according to the actual situation.

[0118] According to one embodiment of the present invention, a condensation reaction unit is included for receiving first light oil from a first separation unit, and the condensation reaction product is pipelined into a low-sulfur petroleum coke production unit for processing. The condensation reaction unit is provided with at least one reactor, preferably a fixed-bed reactor.

[0119] According to one embodiment of the present invention, the regenerated solvent obtained from the solvent recovery unit is returned to the extraction unit via pipeline for reuse.

[0120] According to one embodiment of the present invention, the hydrogenation reaction unit includes at least one hydrogenation reactor. When there are two or more hydrogenation reactors, there are no particular restrictions on the connection method between the reactors, and they are generally connected in series. The reactor can be one or a combination of several of the following: fluidized bed reactor, suspended bed reactor, fixed bed reactor, etc., preferably a fixed bed reactor.

[0121] According to one embodiment of the present invention, the hydrogenation separation unit includes a hot high-pressure separator, a cold high-pressure separator, a hot low-pressure separator, and a cold low-pressure separator, and may also include equipment such as a stripping tower and a fractionation tower.

[0122] According to one embodiment of the present invention, the first separation system may be one or a combination of several of the following: stripping tower, flash tower, fractionation tower, etc., preferably a fractionation tower.

[0123] According to one embodiment of the present invention, the second separation unit may be one or a combination of several of the following: stripping tower, flash tower, fractionation tower, etc., preferably a fractionation tower.

[0124] 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 pipeline; or it enters the condensation reaction unit to undergo a condensation reaction, and the resulting condensation product enters the low-sulfur petroleum coke production unit for the production of low-sulfur petroleum coke; or part of it is recycled back to the hydrotreating unit; and the remaining part enters the condensation reaction unit.

[0125] According to one embodiment of the present invention, a low-sulfur petroleum coke production unit includes at least one heater, two coke towers, and one coking fractionation tower. The coke towers are always kept in at least one reaction stage and at least one purging and decoking stage.

[0126] According to one embodiment of the present invention, the needle coke production unit includes at least one heating furnace, two coke towers, and one coking fractionation tower. At least one coke tower is always in the reaction stage, and at least one is in the purging and decoking stage.

[0127] A specific embodiment of the present invention will now be described in detail with reference to the accompanying drawings.

[0128] like Figure 1As shown, according to the present invention, ethylene tar 2 enters the extraction unit 9, and after contacting the solvent 14, it reacts to obtain the extract phase 16 and the raffinate phase 15. The extract phase 16 enters the solvent recovery unit 10, and after separation, it obtains the regenerated solvent 18 and the aromatic oil 17. The regenerated solvent 18 is returned to the extraction unit 9 for recycling. The aromatic oil enters the first separation unit 11 and is separated to obtain the first light oil 19 and the first heavy oil 20. The first light oil 19 can be discharged or enter the condensation reaction unit 5. The condensation reaction product 27 obtained after the condensation reaction and the raffinate phase 15 enter the low-sulfur petroleum coke production unit 8 together. The first heavy oil 20, the catalytic slurry 1, and the hydrogen 30 enter the hydrogenation reaction unit 3, where a hydrogenation reaction occurs under the action of a hydrogenation catalyst. The hydrogenated product obtained from the reaction... Product 21 enters the hydrotreating separation unit 4, where it is separated to obtain gas 28, naphtha 29, and hydrotreating tail oil 22. The hydrotreating tail oil 22 enters the cracking reaction unit 6, where it undergoes a cracking reaction under the action of carrier gas 7. The cracking product 23 enters the second separation unit 12, where it is separated to obtain second light oil 24, middle distillate oil 25, and second heavy oil 26. The second heavy oil 26 enters the low-sulfur petroleum coke production unit 8 to obtain low-sulfur petroleum coke. The middle distillate oil 25 enters the needle coke production unit 13 to obtain needle coke. The second light oil 24 can be recycled back to the hydrotreating reaction unit 3 for processing, or it can be processed in the condensation reaction 5, or part of it can be recycled back to the hydrotreating reaction unit 3 for processing, and the remainder can be processed in the condensation reaction 5. Example

[0129] The present invention will be further described in detail below with reference to the embodiments, but the present invention is not limited to these embodiments.

[0130] The properties of the catalytic slurry (second feedstock oil) and ethylene tar feedstock used in the embodiments and comparative examples of this invention are shown in Table 1. The trend of TI content in the catalytic slurry with reaction temperature is shown in... Figure 2 The coking initiation temperature of the second feedstock is between 460-465℃. The extractant used in the extraction unit is n-heptane. The hydrogenation catalyst used is the FZC-34BT hydrogenation catalyst developed by the Dalian Research Institute of Petrochemical Technology, Sinopec. Steam is used as the carrier gas in the cracking unit.

[0131] Example 1

[0132] Ethylene tar enters the extraction unit where it contacts and separates from the extractant, yielding raffinate and aromatic oil. The aromatic oil is then separated to obtain first light oil and first heavy oil. The first heavy oil undergoes mild hydrotreating to obtain first feedstock oil. Catalytic slurry is mixed with the first feedstock oil at a mass ratio of 1:0.1 and enters the hydrotreating unit. Hydrotreating products are separated to obtain hydrotreating tail oil. The hydrotreating tail oil enters the cracking unit, where cracking products are separated to obtain middle distillate oil. The middle distillate oil is sent to the needle coke production unit to obtain needle coke. The operating parameters of the extraction unit, hydrotreating unit, cracking unit, and needle coke production unit are listed in Table 2.

[0133] The trend of TI content in the first feedstock as a function of reaction temperature is shown in the figure. Figure 3 The coking initiation temperature of the first feedstock oil is around 440℃.

[0134] The properties of the first feedstock oil are listed in Table 3.

[0135] The properties of needle char are listed in Table 4.

[0136] Example 2

[0137] Ethylene tar enters the extraction unit where it contacts and separates from the extractant, yielding raffinate and aromatic oil. The aromatic oil is then separated to obtain first light oil and first heavy oil, with the first heavy oil serving as the first feedstock. Catalytic slurry is mixed with the first feedstock at a mass ratio of 1:2 and enters the hydrogenation reaction unit. The hydrogenation products are separated to obtain hydrogenation tail oil. The hydrogenation tail oil enters the cracking reaction unit, where the cracking products are separated to obtain middle distillate oil. The middle distillate oil is then sent to the needle coke production unit to obtain needle coke. The operating parameters for the extraction unit, hydrogenation reaction unit, cracking reaction unit, and needle coke production unit are listed in Table 2.

[0138] The trend of TI content in the first feedstock as a function of reaction temperature is shown in the figure. Figure 4 The coking initiation temperature of the first feedstock oil is between 400-405℃.

[0139] The properties of the first feedstock oil are listed in Table 3.

[0140] The properties of needle char are listed in Table 4.

[0141] The polarized microstructure of needle focal foci, such as Figure 5 As shown, the tissue structure of the needle char obtained in Example 2 is mainly composed of large sheets with less fibrous structure.

[0142] Example 3

[0143] Ethylene tar enters the extraction unit where it contacts and separates from the extractant, yielding raffinate and aromatic oil. The aromatic oil is then separated to obtain first light oil and first heavy oil, with the first heavy oil serving as the first feedstock. Catalytic slurry is mixed with the first feedstock at a mass ratio of 1:0.08 and enters the hydrogenation unit. The hydrogenation products are separated to obtain hydrogenation tail oil. This tail oil then enters the cracking unit, where the cracking products are separated to obtain second light oil, middle distillate oil, and second heavy oil. The middle distillate oil is sent to the needle coke production unit to obtain needle coke. The operating parameters for the extraction unit, hydrogenation unit, cracking unit, and needle coke production unit are listed in Table 2.

[0144] The raffinate obtained from the extraction unit is mixed with the second heavy oil obtained from the second separation unit and sent to the low-sulfur petroleum coke production unit. The operating conditions are: furnace outlet temperature 497℃, coke tower top pressure 0.45MPa, and reaction cycle 28h.

[0145] The properties of the first feedstock oil are listed in Table 3.

[0146] The trend of TI content in the first feedstock as a function of reaction temperature is shown in the figure. Figure 6 The coking initiation temperature of the first feedstock oil is between 405-410℃.

[0147] The properties of needle char are listed in Table 4.

[0148] The polarizing fiber structure of needle-shaped focal foils, such as Figure 7 As shown, the tissue structure of the needle char obtained in Example 3 contains a large number of fibrous structures.

[0149] The sulfur content of low-sulfur petroleum coke is listed in Table 5.

[0150] Example 4

[0151] The process is basically the same as in Example 3, except that: the first light oil obtained from the first separation unit enters the condensation reaction unit, the condensation catalyst support is alumina, the active components are 7.5wt% ZrO2-3.6wt% MoO2, cloverleaf structure, the reaction temperature of the condensation reaction unit is 426℃, the reaction pressure is 1.3MPa, and the residence time is 1.5h, to obtain the condensation product. The condensation product is mixed with the raffinate obtained from the extraction unit and the second heavy oil obtained from the second separation unit, and sent to the low-sulfur petroleum coke production unit.

[0152] The operating parameters of the extraction unit, hydrogenation reaction unit, cracking reaction unit, and needle coke production unit are listed in Table 2.

[0153] The properties of the first feedstock oil are listed in Table 3.

[0154] The trend of TI content in the first feedstock as a function of reaction temperature is shown in the figure. Figure 8The coking initiation temperature of the first feedstock oil is between 407-410℃.

[0155] The properties of needle char are listed in Table 4.

[0156] The sulfur content of low-sulfur petroleum coke is listed in Table 5.

[0157] Comparative Example 1

[0158] The catalytic slurry enters the hydrotreating unit, where the hydrotreating products are separated to obtain hydrotreating tail oil. The hydrotreating tail oil then enters the cracking unit, where the cracking products are separated to obtain middle distillate oil. The middle distillate oil is sent to the needle coke production unit to obtain needle coke. The operating parameters of the hydrotreating unit, cracking unit, and needle coke production unit are listed in Table 6.

[0159] The properties of needle char are listed in Table 7.

[0160] Comparative Example 2

[0161] Ethylene tar enters the hydrogenation reaction unit, and the hydrogenation products are separated to obtain hydrogenated tail oil. The hydrogenated tail oil enters the cracking reaction unit, and the cracking products are separated to obtain middle distillate oil. The middle distillate oil is sent to the needle coke production unit to obtain needle coke. The operating parameters of the hydrogenation reaction unit, cracking reaction unit, and needle coke production unit are listed in Table 6.

[0162] The trend of TI content in ethylene tar with reaction temperature is shown in the figure. Figure 9 The coking initiation temperature of ethylene tar is between 395-397℃.

[0163] The properties of needle char are listed in Table 7.

[0164] The polarizing fiber structure of needle-shaped focal foils, such as Figure 10 As shown, the needle-like char obtained in Comparative Example 2 has a poor tissue structure, mainly consisting of large flakes with interspersed mosaic structures.

[0165] Comparative Example 3

[0166] Catalytic oil slurry and ethylene tar are mixed at a mass ratio of 1:0.1 and fed into the hydrotreating unit. After separation of the hydrotreating products, hydrotreating tail oil is obtained. The hydrotreating tail oil is sent to the needle coke production unit to obtain needle coke. The operating parameters of the hydrotreating unit and the needle coke production unit are listed in Table 6.

[0167] The properties of needle char are listed in Table 7.

[0168] The polarizing fiber structure of needle-shaped focal foils, such as Figure 11 As shown, the needle-like char obtained in Comparative Example 3 has a poor tissue texture and contains a large number of mosaic structures.

[0169] Comparative Example 4

[0170] Catalytic oil slurry and ethylene tar are mixed at a mass ratio of 1:0.12 and fed into the cracking reaction unit. The cracking products are separated to obtain middle distillate oil. The middle distillate oil is sent to the needle coke production unit to obtain needle coke. The operating parameters of the cracking reaction unit and the needle coke production unit are listed in Table 6.

[0171] The properties of needle char are listed in Table 7.

[0172] Comparative Example 5

[0173] Catalytic oil slurry and ethylene tar are mixed at a mass ratio of 1:0.05 and directly fed to the needle coke production unit to obtain needle coke. The operating parameters of the needle coke production unit are listed in Table 6.

[0174] The properties of needle char are listed in Table 7.

[0175] The trend of furnace tube pressure in the needle coke production unit over time is as follows: Figure 12 As shown, the coking furnace tubes of Comparative Example 5 exhibit severe coking, making the unit unable to operate for extended periods.

[0176] Table 1. Properties of raw materials

[0177]

[0178] Table 2. Unit operation parameters of each embodiment

[0179]

[0180] Table 3 Properties of the first feedstock oil in the examples

[0181]

[0182] Table 4 Properties of needle coke in the examples

[0183]

[0184] Table 5 Properties of low-sulfur petroleum coke

[0185]

[0186] Table 6. Operational parameters of each unit in the comparative example

[0187]

[0188] Table 7 Properties of comparative needle coke

[0189]

[0190] Although Comparative Examples 4 and 5 had high Hastelloy grindability index and particle strength, their sulfur content was >0.5wt%, which did not meet the quality standards for needle coke.

Claims

1. A method for manufacturing needle coke, comprising the following steps: (1) Hydrotreating a mixture of the first feedstock oil and the second feedstock oil to obtain a hydrogenated product; the first feedstock oil is manufactured according to the following steps: (i) Extract ethylene tar with a solvent to obtain an extract phase and a raffinate phase; (ii) Remove the solvent from the extraction phase to obtain an aromatic oil, and then separate the aromatic oil to obtain a first light oil and a first heavy oil, wherein the first heavy oil is the first feedstock oil; (2) The hydrogenation product is separated to obtain light components and hydrogenation tail oil, and then the hydrogenation tail oil is cracked to obtain cracking products; the 5% distillation temperature of the hydrogenation tail oil is 160℃-250℃. (3) The cracking products are separated to obtain second light oil, middle distillate oil and second heavy oil, and then the needle coke is manufactured using the middle distillate oil as raw material; the distillation range of the middle distillate oil is 330℃-530℃; The second feedstock is a catalytic slurry, the aromatic carbon content of the first feedstock is greater than 65 mol%, the aromatic carbon content of the second feedstock is greater than 60 mol%, and the coking initiation temperature of the first feedstock is 10-140℃ lower than that of the second feedstock.

2. The manufacturing method according to claim 1, wherein the aromatic carbon content of the first feedstock oil is 70 mol%-95 mol%, the aromatic carbon content of the second feedstock oil is 70 mol%-90 mol%, and the coking initiation temperature of the first feedstock oil is 35-105°C lower than that of the second feedstock oil.

3. The manufacturing method according to claim 1, wherein the weight ratio of the second raw material oil to the first raw material oil is 1:1 to 1:0.

001.

4. The manufacturing method according to claim 1, wherein the weight ratio of the second raw material oil to the first raw material oil is 1:0.2-1:0.

01.

5. The manufacturing method according to claim 1, wherein the coking initiation temperature of the first feedstock oil is 350℃-420℃, and the coking initiation temperature of the second feedstock oil is 430℃-490℃.

6. The manufacturing method according to claim 1, wherein the coking initiation temperature of the first feedstock oil is 380℃-415℃, and the coking initiation temperature of the second feedstock oil is 450℃-485℃.

7. The manufacturing method according to claim 1, wherein the ash content of the second raw material oil is not higher than 0.01 wt% and the sulfur content is higher than 0.5 wt%, and the ash content of the first raw material oil is not higher than 0.01 wt% and the sulfur content is not higher than 0.1 wt%.

8. The manufacturing method according to claim 1, wherein the ash content of the second raw material oil is not higher than 0.005 wt% and the sulfur content is 0.8 wt%-1.5 wt%, and the ash content of the first raw material oil is not higher than 0.005 wt% and the sulfur content is not higher than 0.03 wt%.

9. The manufacturing method of claim 1, wherein the solvent is selected from C3-C 12 The solvent contains n-alkanes or cycloalkanes, and / or the mass ratio of the ethylene tar to the solvent is 1:0.5-1:

5.

10. The manufacturing method of claim 1, wherein the solvent is selected from C5-C. 12 The solvent contains n-alkanes, and / or the ethylene tar is in a mass ratio of 1:1 to 1:

2.

11. The manufacturing method according to claim 1, wherein the extraction operation temperature is 30°C-110°C.

12. The manufacturing method according to claim 1, wherein the extraction operation temperature is 40°C-80°C.

13. The manufacturing method according to claim 1, wherein the 5% distillation temperature of the first heavy oil is 300°C-400°C.

14. The manufacturing method according to claim 1, wherein the 5% distillation temperature of the first heavy oil is 340°C-380°C.

15. The manufacturing method of claim 1, wherein the 95% distillation temperature of the first light oil is 280°C-400°C, and / or, the first light oil undergoes a condensation reaction to obtain a condensation product, and then the condensation product is used to manufacture petroleum coke.

16. The manufacturing method of claim 1, wherein the 95% distillation temperature of the first light oil is 335°C-380°C, and / or, the first light oil undergoes a condensation reaction to obtain a condensation product, and then the condensation product is used to manufacture petroleum coke.

17. The manufacturing method according to claim 15 or 16, wherein the operating conditions of the condensation reaction include: The reaction temperature is 350℃-530℃, the reaction pressure is 0.01MPa-5MPa, and the residence time is 0.1h-15h.

18. The manufacturing method according to claim 15 or 16, wherein the operating conditions of the condensation reaction include: The reaction temperature is 380℃-450℃, the reaction pressure is 1MPa-3MPa, and the residence time is 0.5h-6h.

19. The manufacturing method of claim 1, wherein the operating conditions for the hydrogenation treatment include: The reaction temperature was 310℃-450℃, the reaction pressure was 2MPa-20MPa, the hydrogen-to-oil volume ratio was 100-2500, and the liquid hourly space velocity was 0.1h. -1 -2.0h -1 .

20. The manufacturing method of claim 1, wherein the operating conditions for the hydrogenation treatment include: The reaction temperature was 340℃-390℃, the reaction pressure was 4MPa-8MPa, the hydrogen-to-oil volume ratio was 800-1800, and the liquid hourly space velocity was 0.6h⁻¹. -1 -1.2h -1 .

21. The manufacturing method according to claim 1, wherein the sulfur content of the hydrotreated tail oil is not higher than 0.4 wt%.

22. The manufacturing method of claim 1, wherein the 5% distillation temperature of the hydrotreated tail oil is 180°C-210°C, and / or the sulfur content of the hydrotreated tail oil is not higher than 0.35 wt%.

23. The manufacturing method of claim 1, wherein the cracking operating conditions include: The reaction temperature is 380℃-520℃, the reaction pressure is 0.1MPa-5MPa, the residence time is 0.01h-30h, and the oil-gas mass ratio is 100:0.1-100:

20.

24. The manufacturing method of claim 1, wherein the cracking operating conditions include: The reaction temperature is 420℃-490℃, the reaction pressure is 0.2MPa-1.0MPa, the residence time is 0.1h-3h, and the oil-gas mass ratio is 100:1-100:

8.

25. The manufacturing method according to claim 1, wherein the distillation range of the middle distillate oil is 350°C-500°C.

26. The manufacturing method according to claim 1, wherein the 95% distillation temperature of the second light oil is 300°C-400°C, and the 5% distillation temperature of the second heavy oil is 460°C-550°C.

27. The manufacturing method according to claim 1, wherein the 95% distillation temperature of the second light oil is 320°C-380°C, and the 5% distillation temperature of the second heavy oil is 485°C-510°C.

28. The manufacturing method of claim 1, wherein at least a portion of the second light oil is recycled back to the hydrotreating process; or, at least a portion of the second light oil undergoes a condensation reaction to obtain a condensation product, which is then used to manufacture petroleum coke; or, a portion of the second light oil is recycled back to the hydrotreating process, and another portion undergoes the condensation reaction.

29. The manufacturing method of claim 1, wherein the raffinate phase and the second heavy oil are mixed, and the resulting mixture is then used to manufacture petroleum coke, and / or the mass ratio of the raffinate phase to the second heavy oil is 1:1 to 0.01:

1.

30. The manufacturing method of claim 1, wherein the raffinate phase and the second heavy oil are mixed, and the resulting mixture is then used to manufacture petroleum coke, and / or the mass ratio of the raffinate phase to the second heavy oil is 0.5:1 to 0.1:

1.

31. The manufacturing method according to claim 28, 29 or 30, wherein the operating conditions for manufacturing petroleum coke include: The outlet temperature of the heating furnace is 440℃-550℃, the pressure at the top of the coke tower is 0.01MPa-2.5MPa, and the reaction cycle is 10h-48h.

32. The manufacturing method according to claim 28, 29 or 30, wherein the operating conditions for manufacturing petroleum coke include: The outlet temperature of the heating furnace is 490℃-510℃, the pressure at the top of the coke tower is 0.1MPa-0.5MPa, and the reaction cycle is 18h-30h.

33. The manufacturing method of claim 1, wherein the operating conditions for manufacturing the needle coke include: The outlet temperature of the heating furnace is 420℃-560℃, the pressure at the top of the coke tower is 0.01MPa-2.5MPa, and the reaction cycle is 10h-72h.

34. The manufacturing method of claim 1, wherein the operating conditions for manufacturing the needle coke include: The outlet temperature of the heating furnace is 440℃-530℃, the pressure at the top of the coke tower is 0.2MPa-1.3MPa, and the reaction cycle is 32h-54h.

35. An apparatus for manufacturing needle coke according to any one of claims 1-34, comprising the following units: The feedstock supply unit is configured to provide a first feedstock and a second feedstock. Hydrogenation unit: configured to hydrogenate a mixture of the first feedstock oil and the second feedstock oil to obtain a hydrogenated product; Cracking unit: configured to crack the hydrogenation products to obtain cracked products; Needle coke production unit: configured to manufacture needle coke using the cracking products as raw materials. The first feedstock oil has an aromatic carbon content greater than 65 mol%, the second feedstock oil has an aromatic carbon content greater than 60 mol%, and the coking initiation temperature of the first feedstock oil is 10-140℃ lower than that of the second feedstock oil.

36. The manufacturing apparatus of claim 35, wherein the aromatic carbon content of the first feedstock oil is 70 mol%-95 mol%, the aromatic carbon content of the second feedstock oil is 70 mol%-90 mol%, and the coking initiation temperature of the first feedstock oil is 35-105°C lower than that of the second feedstock oil.

37. The manufacturing apparatus of claim 35, comprising the following units: Extraction unit: configured to receive ethylene tar and solvent, and after processing, obtain extract phase and raffinate phase; Solvent recovery unit: configured to receive the extract phase from the extraction unit, and after separation, obtain regenerated solvent and aromatic oil; First separation unit: configured to receive aromatic oil from solvent recovery unit, and after cutting, obtain first light oil and first heavy oil, the first heavy oil corresponding to the first feed oil; Hydrogenation reaction unit: configured to receive the first feedstock oil and catalytic slurry, the catalytic slurry corresponding to the second feedstock oil, and undergo a hydrogenation reaction under the action of hydrogen and a hydrogenation catalyst; Hydrogenation separation unit: configured to receive hydrogenation products from the hydrogenation reaction unit, and separate them to obtain gas, naphtha and hydrogenation tail oil; Cracking reaction unit: It is configured to receive hydrotreated tail oil from the hydrodegassing unit and undergo cracking reaction under the action of carrier gas; The second separation unit is configured to receive cracking products from the cracking reaction unit and separate them to obtain second light oil, middle distillate oil and second heavy oil. Needle coke production unit: configured to receive the intermediate distillate oil and react it to obtain needle coke.

Images