A method and system for preparing raw materials for producing needle coke

Abstract

The present invention provides a method for preparing raw materials for producing needle coke, comprising: mixing raw oil and an oil-soluble hydrogenation catalyst to obtain feed oil, then sending the feed oil into a slurry bed hydrogenation reactor to contact with hydrogen and perform selective hydrogenation treatment to obtain a hydrogenation product; then separating vacuum distillate oil from the hydrogenation product; the oil-soluble hydrogenation catalyst is composed of a complex formed by a metal central atom or central ion and an organic ligand bonded by a coordination bond. The present invention also provides a system for producing raw materials for needle coke, the system comprising a mixing tank, a slurry bed hydrogenation reactor, a thermal high fractionation device and a vacuum distillation device connected in sequence. After the catalytic cracking oil slurry is treated by the method of the present invention, more VGO fraction oil can be effectively cut out to enter the subsequent coking device, and the content of impurities such as sulfur and nitrogen in the VGO fraction oil is further effectively reduced, and the content of three-ring and four-ring aromatic hydrocarbons is further increased.

Description

Technical Field

[0001] The present invention relates to the field of petrochemical industry, and in particular to a method for preparing a raw material for producing needle coke and a system for preparing a raw material for producing needle coke. Background Art

[0002] Needle coke is a silver-grey, metallic-luster solid with a distinct elongated needle-like or fibrous texture on the surface. It has a distinct anisotropic fibrous structure under a microscope. It is mainly used as a raw material for the production of ultra-high power graphite electrodes and artificial graphite negative electrode materials. Its most important terminal application areas are electric arc furnace steelmaking and power batteries for new energy vehicles. With the proposal of the strategic goals of "carbon peak" and "carbon neutrality", the country continues to promote the adjustment and transformation and upgrading of the industrial structure of the steel and automobile industries, and vigorously promotes the application of energy-saving, low-carbon and green environmental protection technologies, which has promoted the rapid development of electric arc furnace steelmaking and new energy vehicles, and the demand for raw material needle coke has also grown rapidly.

[0003] The production of needle coke can be divided into petroleum-based and coal-based. Among them, petroleum-based needle coke is mostly made from heavy distillate oil; while coal-based needle coke is mostly made from coal tar pitch and its distillate oil. The raw material source of petroleum-based needle coke is stable, the pretreatment process is simple, and the needle coke produced has excellent performance and can meet the downstream requirements for high-quality needle coke. The quality of catalytic cracking slurry is crucial to the production of high-quality needle coke. At the same time, it is also necessary to significantly improve the conversion rate of catalytic cracking slurry in the production of needle coke raw materials to solve its resource limitation problem.

[0004] 201610970275.7 provides a method and device for preparing needle coke raw materials, which mainly hydrogenates catalytic oil slurry and coking oil slurry in a fixed bed reactor, wherein the active components of the catalyst are at least two of nickel, tungsten, cobalt and molybdenum, and the carrier is one of alumina and molecular sieve. The hydrogenation product of the method can be used as a needle coke raw material after further treatment.

[0005] However, the proportion of vacuum distillate oil (VGO distillate oil) in the existing catalytic oil slurry hydrogenation product still needs to be further improved, and the content of impurities such as sulfur and nitrogen in the VGO distillate oil still needs to be further reduced, and the content of three-ring and four-ring aromatic hydrocarbons also needs to be further increased. Summary of the invention

[0006] The purpose of the present invention is to further increase the proportion of vacuum distillate oil (VGO distillate oil) in the catalytic oil slurry hydrogenation product, further reduce the content of impurities such as sulfur and nitrogen in the VGO distillate oil, and further increase the content of three-ring and four-ring aromatic hydrocarbons in the VGO distillate oil.

[0007] In order to achieve the above-mentioned object, the present invention provides a method for preparing a raw material for producing needle coke, the method comprising: mixing a raw material oil and an oil-soluble hydrogenation catalyst to obtain a feed oil, then sending the feed oil into a slurry bed hydrogenation reactor to contact with hydrogen and perform selective hydrogenation treatment to obtain a hydrogenation product; then separating a vacuum distillate from the hydrogenation product; wherein the oil-soluble hydrogenation catalyst is composed of a complex formed by a metal central atom or a central ion and an organic ligand through a coordination bond, wherein the metal is selected from VB group metals, VIB group metals, VIII group metals, IB group metals or various combinations thereof having hydrogenation performance, the organic ligand comprises a hydrocarbon group part and a coordination group part, wherein the coordination group is a -C(=O)-O group, and forms a coordination bond with the metal central atom or central ion through an oxygen atom, and the infrared spectrum of the catalyst is 700-1000cm -1 1350-1450cm -1 and 1500-1610cm -1 There is a characteristic peak at the position.

[0008] The present invention also provides a system for preparing raw materials for producing needle coke by carrying out the method as described above, the system comprising a mixing tank, a slurry bed hydrogenation reactor, a thermal high fractionation device and a vacuum distillation device which are connected in sequence; the mixing tank is provided with a raw oil inlet and a mixing tank inlet; the slurry bed is also provided with a hydrogen inlet, and the bottom outlet of the thermal high fractionation device is connected to the inlet of the vacuum distillation device.

[0009] Through the above technical scheme, the hydrogenation catalyst used in the present invention has a high oil phase dispersibility, and the catalytic cracking oil slurry is subjected to hydrogenation treatment in a slurry bed hydrogenation reactor to a homogeneous catalytic reaction, thereby eliminating the diffusion step of the multiphase catalytic reaction. In addition, it has a directional hydrogenation effect, and not only has a high sulfur and nitrogen removal rate under low hydrogen consumption, but also ensures a high aromatic content in the product. When the method and system of the present invention are used to process catalytic cracking oil slurry, the raw material restriction is low, and the catalytic cracking oil slurry can be used directly. After the catalytic cracking oil slurry is processed by the method and system of the present invention, more VGO fractions can be effectively cut out to enter the subsequent coking unit. The content of impurities such as sulfur and nitrogen in the VGO fraction obtained after cutting is further effectively reduced, and the content of three-ring and four-ring aromatics is further increased, thereby ensuring the quality of the needle coke product, and it is an ideal raw material for producing high-end carbon materials such as needle coke.

[0010] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0012] Figure 1 Schematic diagram of a preferred embodiment of a system for producing a raw material for needle coke according to the present invention.

[0013] Figure 2 It is the infrared spectra of the oil-soluble catalysts C1 and C2 of the present invention, the upper figure is C1, and the lower figure is C2.

[0014] Description of Reference Numerals

[0015] 1. Preheating furnace; 2. Mixing tank; 3. Hydrogen preheating furnace; 4. Slurry bed hydrogenation reactor; 5. Hot high fractionation device; 6. Cold high fractionation device; 7. Cold low fractionation device; 8. Water washing unit; 9. Vacuum distillation tower. DETAILED DESCRIPTION

[0016] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0017] The invention provides a method for preparing a raw material for producing needle coke, the method comprising: mixing a raw material oil and an oil-soluble hydrogenation catalyst to obtain a feed oil, then sending the feed oil into a slurry bed hydrogenation reactor to contact with hydrogen and perform selective hydrogenation treatment to obtain a hydrogenation product; then separating a vacuum distillate oil from the hydrogenation product; wherein the oil-soluble hydrogenation catalyst is composed of a complex formed by a metal central atom or a central ion and an organic ligand through a coordination bond, wherein the metal is selected from VB group metals, VIB group metals, VIII group metals, IB group metals or various combinations thereof with hydrogenation performance, the organic ligand comprises a hydrocarbon group part and a coordination group part, wherein the coordination group is a -C(=O)-O group, and forms a coordination bond with the metal central atom or central ion through an oxygen atom, and the infrared spectrum of the catalyst is 700-1000cm -1 1350-1450cm -1 and 1500-1610cm -1 There is a characteristic peak at the position.

[0018] The oil-soluble hydrogenation catalyst is composed of the complex only and does not contain any solid carrier component. However, as required, the oil-soluble hydrogenation catalyst can also be present and used in the form of a composition formed with a liquid component capable of dispersing the catalyst, such as an organic solvent and an organic ligand compound.

[0019] Wherein, depending on the metal used, in the complex of the present application, the VB group metal, VIB group metal, VIII group metal and IB group metal having hydrogenation performance may be in the form of a central atom or a central ion.

[0020] Wherein, the oil-soluble hydrogenation catalyst has a schematic composition shown in formula (I):

[0021] MO a [R(COO) x ] b (I)

[0022] Wherein M represents the metal, R(COO) x represents the organic ligand, R represents the hydrocarbon group in the organic ligand, COO represents the coordinating group in the organic ligand, x represents the number of coordinating groups in the organic ligand, a represents the molar ratio of the non-coordinating bonded oxygen atoms connected to the metal M to the metal M, and b represents the molar ratio of the organic ligand to the metal M.

[0023] Wherein, R is a C3-C19 hydrocarbon group, preferably selected from C5-C11 normal alkyl, C5-C11 isomeric alkyl, C5-C12 cycloalkyl, C6-C12 aryl or a combination thereof; x is 1, 2 or 3, preferably 1 or 2; a is 0-3, preferably a positive number of 1-3; and b is a positive number of 1-6, preferably a positive number of 2-5.

[0024] According to the present application, the oil-soluble hydrogenation catalyst can be a mixture of multiple different complexes, and the molar ratios a and b of the oxygen atoms and organic ligands to the metal M in the catalyst composition are calculated values ​​based on metal content and elemental composition analysis, and can therefore be non-integers. When M is a metal, the molar ratios a and b are molar ratios relative to the metal; and when M is a combination of two or more metals, the molar ratios a and b are molar ratios relative to the total amount of all metals. In addition, the metal M portion (such as MoNi, MoFeV, etc.) in the catalyst composition only indicates which metals are present and does not indicate the molar ratio relationship between the metals.

[0025] In certain further preferred embodiments, M comprises M 1 and M 2 , M 1 and M 2 Different from each other. 1 and M 2 Representative metals are different from each other and are independently selected from one of the VB group metals, VIB group metals, VIII group metals and IB group metals having hydrogenation properties. In these preferred embodiments, better hydrogenation effects can be achieved.

[0026] In certain further preferred embodiments, the VB group metal, VIB group metal, VIII group metal and IB group metal having hydrogenation properties are selected from V, Cr, Mo, W, Fe, Co, Ru, Ni, Cu and Pd, preferably selected from Mo, Ni, W, Fe, V and Co.

[0027] In the present application, the term "C3-C19 hydrocarbon group" refers to a hydrocarbon group having 3-19 carbon atoms, which may be saturated or unsaturated, a straight chain, a branched chain or a hydrocarbon group having a carbocyclic ring, including but not limited to C3-C19 normal alkyl groups, C3-C19 isomeric alkyl groups, C5-C19 cycloalkyl groups and C6-C19 aromatic groups.

[0028] In the present application, the term "C3-C19 normal alkyl" refers to a straight chain alkyl group having 3-19 carbon atoms, preferably a straight chain alkyl group having 5-11 carbon atoms, such as n-pentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, and n-undecyl.

[0029] In the present application, the term "C3-C19 isomeric alkyl" refers to a branched alkyl group having 3-19 carbon atoms, preferably an isomeric alkyl group having 5-11 carbon atoms, such as isopentyl, isohexyl, isoheptyl, isooctyl, isononyl, isodecyl, isoundecyl, etc.

[0030] In the present application, the term "C5-C19 cycloalkyl group" refers to a saturated hydrocarbon group containing a saturated carbocyclic ring having 5-19 carbon atoms, preferably a cycloalkyl group having 5-12 carbon atoms, such as cyclopentyl, cyclohexyl, methylcyclohexyl, decahydronaphthyl, methyldecahydronaphthyl, ethyldecahydronaphthyl, and the like.

[0031] In the present application, the term "C6-C19 aryl" refers to a group containing an aromatic ring having 6-19 carbon atoms, such as phenyl, naphthyl, anthracenyl, p-tolyl, benzyl, methylnaphthyl, methylanthryl, etc., preferably an aryl group having 6-12 carbon atoms.

[0032] According to the present application, the C3-C19 hydrocarbon group, C3-C19 normal alkyl group, C3-C19 isomeric alkyl group, C5-C19 cycloalkyl group and C6-C19 aryl group may be optionally substituted, for example, may be unsubstituted, or may be substituted by one or more groups selected from halo, nitro, sulfonic acid, etc.

[0033] In certain further preferred embodiments, the organic ligand is derived from a C4-C20 organic carboxylic acid, preferably derived from one or more of a C4-C20 normal or isomeric alkyl carboxylic acid, a C6-C20 cycloalkane carboxylic acid containing a saturated carbon ring, and a C7-C20 aromatic carboxylic acid containing an aromatic ring, more preferably derived from one or more of a C6-C12 normal or isomeric alkyl carboxylic acid, a C6-C13 cycloalkane carboxylic acid containing a saturated carbon ring, and a C7-C13 aromatic carboxylic acid containing an aromatic ring, further preferably derived from one or more of succinic acid, hexanoic acid, adipic acid, heptanoic acid, octanoic acid, nonanoic acid, ethylhexanoic acid, oleic acid, petroleum acid, salicylic acid, benzoic acid, and phenylacetic acid.

[0034] In certain further preferred embodiments, the metal content of the catalyst is 5-35%, preferably 8-30%, more preferably 10-25%, particularly preferably 10-20%, calculated as metal and based on the weight of the oil-soluble hydrogenation catalyst.

[0035] The preparation method of the oil-soluble hydrogenation catalyst of the present application may include the step of reacting a VB group metal, a VIB group metal, a VIII group metal, an IB group metal, an oxide, a hydroxide and / or a metal inorganic salt thereof having hydrogenation performance with an organic ligand compound, wherein the organic ligand compound is selected from an organic carboxylic acid of C4-C20.

[0036] In a preferred embodiment, the VB group metal, VIB group metal, VIII group metal and IB group metal having hydrogenation performance are selected from V, Cr, Mo, W, Fe, Co, Ru, Ni, Cu and Pd, more preferably selected from Mo, Ni, W, Fe, V and Co.

[0037] According to the present application, the metal inorganic salt may be an inorganic acid salt of the metal, such as nitrate, sulfate, chloride; or a metal oxygen-containing acid salt of the metal, such as ammonium molybdate, ammonium metavanadate.

[0038] In a preferred embodiment, the reaction temperature of the reaction is 100-350° C., preferably 160-280° C., and the reaction time is 1-8 h, preferably 2-6 h.

[0039] According to the present application, the reaction can be carried out in the absence of water or in the presence of water (eg, 0-10 times the weight of water relative to the weight of the organic ligand compound).

[0040] According to the present application, the reaction can be carried out in the absence of other components (such as catalysts, alkaline pH regulators, etc.) except the metal with hydrogenation properties, its oxide, its hydroxide and / or its metal inorganic salt, organic ligand compound and optional solvent (such as water and organic solvents such as toluene, ethanol, diesel, etc.).

[0041] In a preferred embodiment, the organic ligand compound is selected from normal or isomeric alkyl carboxylic acids of C4-C20, cycloalkane carboxylic acids containing saturated carbon rings of C6-C20, aromatic carboxylic acids containing aromatic rings of C7-C20, or a combination thereof, preferably selected from normal or isomeric alkyl carboxylic acids of C6-C12, cycloalkane carboxylic acids containing saturated carbon rings of C6-C13, aromatic carboxylic acids containing aromatic rings of C7-C13, or a combination thereof, more preferably selected from succinic acid, hexanoic acid, adipic acid, heptanoic acid, octanoic acid, nonanoic acid, ethylhexanoic acid, oleic acid, petroleum acid, salicylic acid, benzoic acid, phenylacetic acid, or a combination thereof.

[0042] Optionally, the oil-soluble hydrogenation catalyst is used in the form of a catalyst composition, which comprises the oil-soluble hydrogenation catalyst and at least one organic ligand compound and / or organic solvent.

[0043] Wherein, the organic ligand compound is selected from C4-C20 organic carboxylic acids, preferably selected from C4-C20 normal or isomeric alkyl carboxylic acids, C6-C20 cycloalkane carboxylic acids containing saturated carbon rings, C7-C20 aromatic carboxylic acids containing aromatic rings or combinations thereof, more preferably selected from C6-C12 normal or isomeric alkyl carboxylic acids, C6-C13 cycloalkane carboxylic acids containing saturated carbon rings, C7-C13 aromatic carboxylic acids containing aromatic rings or combinations thereof, further preferably selected from succinic acid, hexanoic acid, adipic acid, heptanoic acid, octanoic acid, nonanoic acid, ethylhexanoic acid, oleic acid, petroleum acid, salicylic acid, benzoic acid, phenylacetic acid or combinations thereof.

[0044] The organic solvent is selected from aliphatic hydrocarbons, aromatic hydrocarbons, alicyclic hydrocarbons, halogenated hydrocarbons, alcohol solvents, ether solvents, ester solvents, ketone solvents or combinations thereof, preferably selected from toluene, gasoline, ethanol, diesel, or combinations thereof.

[0045] Optionally, the catalyst composition comprises at least one organic ligand compound, and the infrared spectrum of the composition is between 700 and 1000 cm -1 1350-1450cm -1 1500-1610cm -1 and 1700-1750cm -1 There is a characteristic peak at the position.

[0046] Optionally, the catalyst composition contains 50-95% of the oil-soluble hydrogenation catalyst, preferably 80-95% of the catalyst composition by weight; and the total content of the organic ligand compound and the organic solvent is 5-50%, preferably 5-20%.

[0047] In certain embodiments, the hydrogenation catalyst composition may also be used to include other components that improve oil solubility, storage stability and antioxidant properties, such as organic substances with reducing functions such as formic acid, oxalic acid, formaldehyde, ethylenediamine, oleylamine, etc., based on the weight of the composition, the content of the other components can be 0-80%, preferably 0-50%.

[0048] Optionally, the feedstock oil is at least one of heavy distillate oil, catalytic cracking oil slurry, catalytic cracking clarified oil, unhydrogenated vacuum distillate oil, thermal cracking residue oil, coking oil slurry, coal tar and steam cracking residue oil; and the aromatic content of the feedstock oil is above 20% by weight. Wherein, catalytic cracking oil slurry is a heavy fraction in the catalytic cracking product, and its initial boiling point of the distillation range can be any value in 150-230°C, for example, 162°C, and its final boiling point can be any value in 620-700°C, for example, 645°C, and its main component can be unhydrogenated vacuum distillate oil, and the initial boiling point of the unhydrogenated vacuum distillate oil is any temperature between 290-310°C, for example, 300°C, and the final boiling point is any temperature between 490-510°C, for example, 500°C, such as 350-500°C unhydrogenated distillate oil, and other fractions may be involved according to the differences in raw materials and processing conditions.

[0049] Optionally, the vacuum distillate oil has an initial boiling point of any temperature between 290-310° C., such as 300° C., and a final boiling point of any temperature between 490-510° C., such as 500° C. The vacuum distillate oil can be used alone or together with other raw materials as a raw material for producing needle coke.

[0050] Optionally, the amount of the oil-soluble hydrogenation catalyst or its combination is 50-20000 μg / g, preferably 100-10000 μg / g, based on the weight of the feedstock oil, in terms of metal; the initial hydrogen pressure is 1-20 MPa, preferably 2-10 MPa; the reaction temperature is 350-500°C, preferably 380-420°C; the liquid hourly space velocity is 0.05-2.0 h -1 , preferably 0.05-1.0h -1 ; The volume ratio of hydrogen to oil is 300-2000, preferably 500-1500.

[0051] Optionally, the method further comprises: performing a first separation on the hydrogenation product to obtain a first separation product and a second separation product; the first separation product contains naphtha, hydrogen and light oil gas; the second separation product contains heavy oil slurry and the oil-soluble hydrogenation catalyst. The first separation can be performed by a thermal high separation device. The first separation product can be the top effluent of the thermal high separation device. The second separation product can be the bottom effluent of the thermal high separation device.

[0052] Optionally, the method further comprises: subjecting the second separated product to vacuum distillation to obtain atmospheric distillate oil, vacuum distillate oil and circulating tail oil. The cut point between the atmospheric distillate oil and the vacuum distillate oil can be any temperature between 290-310°C, for example, 300°C, and the cut point between the vacuum distillate oil and the circulating tail oil can be any temperature between 490-510°C, for example, 500°C.

[0053] Optionally, the method further comprises: returning the circulating tail oil and mixing it with the feedstock oil and the oil-soluble hydrogenation catalyst for reuse. The circulating tail oil contains residual catalyst and feedstock oil and can be used for hydrogenation treatment again.

[0054] The present invention also provides a system for preparing raw materials for producing needle coke by carrying out the method as described above, the system comprising a mixing tank, a slurry bed hydrogenation reactor, a thermal high fractionation device and a vacuum distillation device connected in sequence; the mixing tank is provided with a raw oil inlet and a mixing tank inlet; the slurry bed hydrogenation reactor is also provided with a hydrogen inlet, and the bottom outlet of the thermal high fractionation device is connected to the inlet of the vacuum distillation device.

[0055] Wherein, the mixing tank is used to mix the feedstock oil and the oil-soluble hydrogenation catalyst. The slurry bed hydrogenation reactor is used to remove heteroatoms such as sulfur and nitrogen in the feedstock oil containing the hydrogenation catalyst to obtain a hydrogenated product with a high aromatic content. The thermal high-fractionation device is used to perform flash thermal separation on the product after the reaction in the slurry bed hydrogenation reactor. The top effluent of the thermal high-fractionation device can be the first separated product containing naphtha, hydrogen and light oil and gas. The bottom effluent of the thermal high-fractionation device can be the second separated product containing heavy oil slurry and the oil-soluble hydrogenation catalyst. The vacuum distillation device can be used to cut the first separated product to obtain atmospheric distillate oil (AGO), vacuum distillate oil (VGO) and circulating tail oil. The bottom discharge port of the thermal high-fractionation device is connected to the feed port of the vacuum distillation device.

[0056] According to a preferred embodiment of the present invention, a preheating furnace for heating the crude oil is also connected upstream of the mixing tank.

[0057] According to a preferred embodiment of the present invention, a circulating tail oil inlet is also provided on the mixing tank, and the circulating tail oil outlet of the vacuum distillation device is connected to the circulating tail oil inlet on the mixing tank.

[0058] Optionally, a hydrogen preheating furnace is connected upstream of the hydrogen inlet to increase the temperature of the hydrogen to a suitable reaction temperature.

[0059] Optionally, the bottom of the hot high fractionation device is connected to the feed inlet of the vacuum distillation device; the top outlet of the hot high fractionation device is also connected to a cold high fractionation device, and the cold high fractionation device is used to separate naphtha components. The top outlet of the cold high fractionation device outputs hydrogen and light oil gas, and the bottom outlet outputs naphtha components. The top outlet of the cold high fractionation device is also connected to a cold low fractionation device, and the cold low fractionation device is used to separate hydrogen and light oil gas. The top outlet of the cold low fractionation device outputs hydrogen and light oil gas, and the bottom outlet outputs light oil gas. The top outlet of the cold low fractionation device is also connected to a water washing unit, and the water washing unit is used to remove NH3 and H2S from hydrogen for recycling.

[0060] The present invention is further illustrated by the following examples, but the present invention is not limited thereto.

[0061] In the following examples, unless otherwise specified, the raw materials used are commercially available products.

[0062] Example 1-2

[0063] Example 1-2 Preparation of Oil-Soluble Hydrogenation Catalyst C1((MoCo)O 1.27 (C7H 16 COO 2.45 ) and C2((Mo 0.7 Ni 0.3 ) 1.4 (C7H 16 COO 3.27 ).

[0064] The reaction raw materials, reaction conditions and test results used in Example 1-2 are shown in Table 1. The corresponding weights of the compounds shown in Table 1 are weighed and placed in a three-necked flask, and then reacted under the conditions shown in Table 1. After the reaction is completed, the metal compound in the flask of Example 1-2 is completely dissolved. The liquid reaction product in the flask of Example 1-2 is poured out to obtain an oil-soluble hydrogenation catalyst.

[0065] The metal content of the obtained oil-soluble hydrogenation catalyst was determined by inductively coupled plasma optical emission spectroscopy (ICP-OES), the elemental composition of the obtained oil-soluble hydrogenation catalyst was measured by a corresponding method, and the composition of the oil-soluble hydrogenation catalyst was obtained according to the measured metal content and elemental composition results. In Table 1, the metal part (such as MoNi, MoCo) in the composition of the obtained oil-soluble hydrogenation catalyst only shows which metals are present but not the molar ratio relationship between the metals.

[0066] The infrared spectra of the oil-soluble hydrogenation catalysts C1 and C2 prepared in Example 1-2 are as follows: Figure 2 As shown in the figure, it can be clearly seen that both C1 and C2 are in the range of 700-1000cm-1 1350-1450cm -1 and 1500-1610cm -1 There is a characteristic peak at the position. 700-1000cm -1 There are M—O and M=O vibration characteristic peaks at 1350-1450cm -1 and 1500-1610cm -1 There is a characteristic peak of -C(=O)-O group coordinated with metal at 1350-1450cm -1 A characteristic peak at 1500-1610cm -1 The distance between the peaks of a characteristic peak at the position is greater than 145 cm -1 , indicating that at least some of the complexes in C1 and C2 have a bimetallic monodentate coordination structure.

[0067] Table 1

[0068]

[0069] Examples 3-4 and Comparative Examples 1-2

[0070] Raw material A is a distillate oil (unhydrogenated vacuum distillate oil) obtained by filtering and vacuum cutting catalytic cracking oil slurry, with a distillation range of 350-500° C., a sulfur content of 1.14%, a nitrogen content of 0.18%, and a three-ring + four-ring aromatic hydrocarbon content of 53.9%.

[0071] A was used as raw material, and a residual oil catalytic hydrogenation thermal conversion test was carried out in an intermittent high-pressure reactor under the catalyst and reaction conditions shown in Table 2. The product obtained by the reaction was distilled and cut, and a VGO fraction oil of 350-500°C was selected. The operating pressure was 10 mmHg at 350°C and 0.3 mmHg at 500°C. The results of the analysis and detection experiments are shown in Table 1. Comparative Examples 1-2 were tested with reference to the examples, except that the oil-soluble hydrogenation catalysts C1 and C2 in Examples 3-4 were replaced by powdered conventional supported catalysts (Ni-Mo supported catalysts for hydrogenation of residual oil, Mo mass content 9.3%, Ni mass content 2.52%) and powdered MoS2 (purity 98%) according to the metal amount equivalent substitution method. The experimental results are shown in Table 2.

[0072] Table 2

[0073] project Example 3 Example 4 Comparative Example 1 Comparative Example 2 catalyst C1 C2 Supported Catalyst <![CDATA[MoS2]]> Reaction temperature / ℃ 400 415 400 400 Reaction time / min 120 120 120 120 Initial hydrogen pressure / MPa 7 7 7 7 Catalyst dosage (in terms of metal) / (μg / g) 2000 2000 2000 2000 S content in the product / % 0.385 0.243 0.486 0.795 N content in the product / % 0.12 0.08 0.17 0.18 (Three-ring + four-ring) aromatic hydrocarbons proportion / % 56.6 54.2 50.0 48.6 350-500℃ distillate oil yield / % 86.55 81.61 80.68 78.6

[0074] It can be seen from the results in Table 2 that, compared with conventional supported and non-oil-soluble catalysts, under the same reaction conditions, when the oil-soluble non-supported selective hydrodesulfurization catalyst and its composition of the present invention are used as catalysts, the content of tricyclic and tetracyclic aromatic hydrocarbons in the product is high, and the sulfur content is also reduced to below 0.5%, which can meet the raw material requirements for producing high-quality needle coke. At the same time, as the temperature increases, the S content of the raw material for preparing needle coke obtained by the method and system of the present application can be further reduced, and the content of tricyclic and tetracyclic aromatic hydrocarbons is also maintained at a high level, which can be used as an ultra-low sulfur raw material to produce high-quality needle coke.

[0075] Example 5 and Comparative Example 3

[0076] Raw material B is catalytic cracking oil slurry with a distillation range of 162-645° C., a sulfur content of 1.07%, a nitrogen content of 0.14%, and a tricyclic + tetracyclic aromatic hydrocarbon content of 47.6%.

[0077] Raw material B was directly processed according to the method of Example 3 to obtain the processing results of Example 5, as shown in Table 3.

[0078] Comparative Example 3 adopts the existing process of producing needle coke in a petrochemical plant. Since the solid content of catalytic oil slurry B is about 400ppm, it cannot be directly put into the fixed bed for hydrogenation treatment, so the catalytic oil slurry B is first filtered and vacuum distilled to cut the 350-500℃ fraction (which will cause losses) to obtain raw oil A with a yield of about 72%. The raw oil A is then hydrogenated in a fixed bed, and the catalyst is the formed supported catalyst of Comparative Example 1 (residue oil hydrogenation Ni-Mo supported catalyst, Mo mass content 9.3%, Ni mass content 2.52%), and the hydrogenation conditions include: hydrogen pressure 4Mpa, reactor temperature 310℃, raw oil liquid hourly space velocity 0.5h -1 , hydrogen to oil volume ratio is 1500. The treatment results of Comparative Example 3 are obtained, as shown in Table 3.

[0079] Table 3

[0080] project Example 5 Comparative Example 3 catalyst C1 Supported Catalyst Reactor Type Slurry bed Fixed bed S content in the product / % 0.406 0.454 N content in the product / % 0.15 0.17 (Three-ring + four-ring) aromatic hydrocarbons proportion / % 61.4 50.8 Whole process product distribution / % Gas and <350℃ 12.73 9.36 350-500℃ 80.52 69.84 >500℃ 6.75 10.8 loss 0 10

[0081] From the results in Table 3, it can be seen that compared with the existing refinery process, the present invention can directly utilize catalytic cracking slurry when using the oil-soluble non-supported selective hydrodesulfurization catalyst and its composition as a catalyst, and can reduce the sulfur content in VGO to below 0.5%, the content of three-ring and four-ring aromatic hydrocarbons in VGO is significantly high, and the yield of VGO with a distillation range of 350-500° C. in the hydrogenation product is also significantly improved. The method of the present invention can make the catalytic slurry produce high-quality needle coke raw materials as much as possible, while reducing the yield of heavy by-products, which is of great significance for the efficient utilization of catalytic slurry.

[0082] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, a variety of simple modifications can be made to the technical solution of the present invention, and these simple modifications all belong to the protection scope of the present invention.

[0083] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any suitable manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0084] In addition, various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A method for preparing a raw material for producing needle coke, characterized in that: The method comprises: mixing the raw material oil and the oil-soluble hydrogenation catalyst to obtain the feed oil, then sending the feed oil into a slurry bed hydrogenation reactor to contact with hydrogen and perform selective hydrogenation treatment to obtain a hydrogenation product; then separating the vacuum distillate oil from the hydrogenation product; The oil-soluble hydrogenation catalyst is composed of a complex formed by a metal central atom or central ion and an organic ligand through a coordination bond, wherein the metal is selected from VB group metals, VIB group metals, VIII group metals, IB group metals or various combinations thereof having hydrogenation performance, the organic ligand comprises a hydrocarbon group part and a coordination group part, wherein the coordination group is a -C(=O)-O group, and forms a coordination bond with the metal central atom or central ion through an oxygen atom, and the infrared spectrum of the catalyst is 700-1000 cm -1 , 1350-1450 cm -1 and 1500-1610 cm -1 There is a characteristic peak at the position; The oil-soluble hydrogenation catalyst has a schematic composition shown in formula (I): MO a [R(COO) x ] b (I), Wherein M represents the metal, R(COO) x represents the organic ligand, R represents the hydrocarbon group in the organic ligand, COO represents the coordination group in the organic ligand, x represents the number of coordination groups in the organic ligand, a represents the molar ratio of the non-coordinating bonded oxygen atoms connected to the metal M to the metal M, and b represents the molar ratio of the organic ligand to the metal M, wherein: R is a C3-C19 hydrocarbon group; x is 1, 2, or 3; a is 0-3; and b is a positive number between 1 and 6; M includes M 1 and M 2 , M 1 and M 2 Different from each other; The metal content of the catalyst is 5-35% calculated as metal and based on the weight of the oil-soluble hydrogenation catalyst; The reaction conditions for the metal central atom or central ion to bond with the organic ligand to form a complex include: a reaction temperature of 100-350° C. and a reaction time of 1-8 h.

2. The method according to claim 1, wherein: R is selected from C5-C11 normal alkyl, C5-C11 isomeric alkyl, C5-C12 cycloalkyl, C6-C12 aryl or a combination thereof; x is 1 or 2; a is a positive number between 1 and 3; and b is a positive number ranging from 2 to 5.

3. The method according to claim 1, wherein: The VB group metal, VIB group metal, VIII group metal and IB group metal having hydrogenation performance are selected from V, Cr, Mo, W, Fe, Co, Ru, Ni, Cu and Pd; The organic ligand is derived from a C4-C20 organic carboxylic acid; The catalyst has a metal content of 8-30% calculated as metal and based on the weight of the oil-soluble hydrogenation catalyst.

4. The method according to claim 3, wherein: The VB group metal, VIB group metal, VIII group metal and IB group metal having hydrogenation performance are selected from Mo, Ni, W, Fe, V and Co; The organic ligand is derived from one or more of a C4-C20 normal or isomeric alkyl carboxylic acid, a C6-C20 cycloalkane carboxylic acid containing a saturated carbon ring, and a C7-C20 aromatic carboxylic acid containing an aromatic ring; The catalyst has a metal content of 10-25% calculated as metal and based on the weight of the oil-soluble hydrogenation catalyst.

5. The method according to claim 4, wherein: The organic ligand is derived from one or more of a C6-C12 normal or isomeric alkyl carboxylic acid, a C6-C13 cycloalkane carboxylic acid containing a saturated carbon ring, and a C7-C13 aromatic carboxylic acid containing an aromatic ring; The catalyst has a metal content of 10-20% calculated as metal and based on the weight of the oil-soluble hydrogenation catalyst.

6. The method according to claim 5, wherein: The organic ligand is derived from one or more of succinic acid, caproic acid, adipic acid, heptanoic acid, caprylic acid, nonanoic acid, ethylhexanoic acid, oleic acid, petroleum acid, salicylic acid, benzoic acid and phenylacetic acid.

7. The method according to any one of claims 1 to 6, wherein: The oil-soluble hydrogenation catalyst is used in the form of a catalyst composition, which comprises the oil-soluble hydrogenation catalyst and at least one organic ligand compound and / or organic solvent, wherein: The organic ligand compound is selected from C4-C20 organic carboxylic acids; The organic solvent is selected from aliphatic hydrocarbons, aromatic hydrocarbons, alicyclic hydrocarbons, halogenated hydrocarbons, alcohol solvents, ether solvents, ester solvents, ketone solvents or combinations thereof.

8. The method according to claim 7, wherein: The organic ligand compound is selected from C4-C20 normal or isomeric alkyl carboxylic acids, C6-C20 cycloalkane carboxylic acids containing saturated carbocyclic rings, C7-C20 aromatic carboxylic acids containing aromatic rings, or combinations thereof; The organic solvent is selected from toluene, gasoline, ethanol, diesel, or a combination thereof.

9. The method according to claim 8, wherein: The organic ligand compound is selected from C6-C12 normal or isomeric alkyl carboxylic acids, C6-C13 cycloalkane carboxylic acids containing saturated carbon rings, C7-C13 aromatic carboxylic acids containing aromatic rings, or combinations thereof.

10. The method according to claim 7, wherein: The organic ligand compound is selected from succinic acid, hexanoic acid, adipic acid, heptanoic acid, octanoic acid, nonanoic acid, ethylhexanoic acid, oleic acid, petroleum acid, salicylic acid, benzoic acid, phenylacetic acid or a combination thereof.

11. The method according to claim 7, wherein: The catalyst composition comprises at least one organic ligand compound, and the infrared spectrum of the composition is between 700 and 1000 cm -1 1350-1450cm -1 1500-1610cm -1 and 1700-1750cm -1 There is a characteristic peak at the position; The catalyst composition has a content of 50-95% of the oil-soluble hydrogenation catalyst based on the weight of the catalyst composition; and a total content of the organic ligand compound and the organic solvent is 5-50%.

12. The method according to claim 11, wherein: The catalyst composition has a content of 80-95% of the oil-soluble hydrogenation catalyst based on the weight of the catalyst composition; and a total content of the organic ligand compound and the organic solvent is 5-20%.

13. The method according to claim 1, wherein: The feedstock oil is a heavy distillate oil, and the aromatic content of the feedstock oil is greater than 20% by weight.

14. The method according to claim 1, wherein: The feedstock oil is selected from at least one of catalytic cracking oil slurry, catalytic cracking clarified oil, unhydrogenated vacuum distillate oil, thermal cracking residue oil, coking oil slurry, coal tar and steam cracking residue oil; and the aromatic content of the feedstock oil is above 20% by weight; The initial boiling point of the unhydrogenated vacuum distillate oil is any temperature between 290-310°C, and the final boiling point is any temperature between 490-510°C.

15. The method according to claim 1, wherein: The amount of the oil-soluble hydrogenation catalyst or its combination is 50-20000 μg / g based on the weight of the raw oil and the metal; the initial hydrogen pressure is 1-20 MPa; the reaction temperature is 350-500 °C; the liquid hourly space velocity is 0.05-2.0 h -1 ; The volume ratio of hydrogen to oil is 300-2000.

16. The method according to claim 15, wherein: The amount of the oil-soluble hydrogenation catalyst or its combination is 100-10000 μg / g based on the weight of the raw oil and the metal; the initial hydrogen pressure is 2-10 MPa; the reaction temperature is 380-420°C; the liquid hourly space velocity is 0.05-1.0 h -1 ; The volume ratio of hydrogen to oil is 500-1500.

17. The method according to claim 1, wherein: The method further includes: The hydrogenation product is subjected to a first separation to obtain a first separation product and a second separation product; the first separation product contains naphtha, hydrogen and light oil gas; the second separation product contains heavy oil slurry and the oil-soluble hydrogenation catalyst; The second separated product is subjected to vacuum distillation to obtain atmospheric distillate oil, vacuum distillate oil and circulating tail oil; The circulating tail oil is returned and mixed with the feedstock oil and the oil-soluble hydrogenation catalyst for reuse.

18. A system for preparing a raw material for producing needle coke by carrying out the method according to any one of claims 1 to 17, characterized in that: The system comprises a mixing tank, a slurry bed hydrogenation reactor, a thermal high fractionation device and a vacuum distillation device which are connected in sequence; the mixing tank is provided with a raw oil inlet and a mixing tank inlet; the slurry bed hydrogenation reactor is also provided with a hydrogen inlet, and the bottom outlet of the thermal high fractionation device is connected to the inlet of the vacuum distillation device.

19. The system of claim 18, wherein: A preheating furnace for heating the crude oil is also connected upstream of the mixing tank; The mixing tank is also provided with a circulating tail oil inlet, and the circulating tail oil outlet of the vacuum distillation device is connected to the circulating tail oil inlet on the mixing tank.

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