Hydrotreatment method and system for aromatic-rich raw material

Abstract

The invention provides an aromatic-rich raw material hydrotreating method and system.The method comprises the steps that an aromatic-rich raw material or a mixture of the aromatic-rich raw material and a heavy oil fraction is subjected to enhanced hydrogen mixing with hydrogen, and a gas-liquid emulsion material flow is obtained; enabling the gas-liquid emulsion flow to sequentially pass through an up-flow fixed bed reactor and a trickle bed reactor which are connected in series and are internally and respectively provided with catalyst bed layers to generate hydrogenation reaction, so as to obtain a hydrogenation product; wherein the hydrogenation reaction temperature of the up-flow fixed bed reactor is 5-20 DEG C lower than that of the trickle bed reactor; carrying out gas-liquid separation on the hydrogenation product to obtain a gas-phase material flow and a liquid-phase material flow; and fractionating the liquid-phase material flow to obtain a light oil fraction and a heavy oil fraction. On the premise of canceling a recycle hydrogen system and reducing investment cost and hydrogen consumption, the aromatic-rich raw material is treated, high-efficiency impurity removal is guaranteed, meanwhile, over-saturation of aromatic hydrocarbon can be inhibited, long-period stable operation of the system is achieved, and the product meets the requirement for producing a carbon material.

Description

Technical Field

[0001] The invention relates to a method and system for hydrogenating aromatic raw materials, belonging to the technical field of petrochemical hydrogenation. Background Art

[0002] With the rapid development of new energy technologies, there is a strong demand for carbon materials for battery negative electrodes with high added value. Heavy crude oil rich in aromatics, catalytic oil slurry in secondary processed oil, ethylene tar, etc. are theoretically ideal raw materials for producing carbon materials. However, precisely because these raw materials have high content of polycyclic aromatic hydrocarbons and high content of impurities such as sulfur, nitrogen, metals, and ash, there is currently no representative technology for their efficient processing and utilization.

[0003] Among the currently used technologies for hydrogenation and decontamination of aromatic-rich heavy oil raw materials, the fixed bed process is mature, easy to operate, and has a low investment in equipment, and can be used as a pretreatment technology for petroleum-based carbon material raw materials. However, the traditional fixed-bed hydrogenation and decontamination technology is mainly based on trickle bed reactors, which requires maintaining a high hydrogen-oil volume ratio under a certain hydrogen partial pressure, so that the continuous phase in the reactor is gas and the dispersed phase is liquid. Therefore, a large amount of circulating hydrogen is required for interphase mass transfer and heat transfer, and thus a circulating hydrogen system needs to be set up, which has high energy consumption and large investment. When processing raw materials with high polycyclic aromatic hydrocarbon content and metal content, the catalyst is prone to coking, deactivation and agglomeration, causing the reactor to shut down due to increased pressure drop in a short period of time, affecting the long-term operation of the device. At the same time, the loss of aromatics is large, which is not conducive to the further production of needle coke.

[0004] The liquid phase hydrogenation process currently used mainly solves the problem of low hydrogen solubility in heavy oil raw materials through measures such as pre-mixing hydrogen, inter-stage hydrogen replenishment, and circulating hydrogen dissolution. However, due to the large particle size of hydrogen bubbles formed during the hydrogen dissolution process, they are easy to aggregate and precipitate, resulting in the hydrogen solubility of heavy oil raw materials and their hydrogenation products being far lower than the chemical hydrogen consumption of the reaction, which limits the application of liquid phase hydrogenation processes in hydrogenation processes such as high hydrogen consumption, heavy oil, and inferior oil. Therefore, in recent years, enhanced hydrogen mixing has become a research hotspot. Through a static mixer or power mixer with a special structure, the mixing effect of hydrogen in oil products can be enhanced, so that the hydrogen bubbles reach the micron level and can exist stably for a long time, so that the hydrogen content of the liquid phase in the reaction system exceeds the chemical hydrogen consumption.

[0005] CN101250433A discloses a coal tar hydrogenation process, in which coal tar is pretreated to obtain coal tar hydrogenation feed, and then passes through an upflow pre-hydrogenation fixed bed reactor and a downflow main hydrogenation fixed bed reactor connected in series, and is fractionated to obtain a gasoline fraction, a diesel fraction and a light fuel oil fraction; the purpose of the process is to produce fuel oil, there is no enhanced hydrogen mixing unit and no proposal to cancel the circulating hydrogen system, the reaction system has poor gas-liquid mass transfer and high investment.

[0006] CN116036999A discloses a maleic anhydride hydrogenation system and a method for preparing succinic anhydride by hydrogenation of maleic anhydride, wherein the method comprises mixing maleic anhydride solution and hydrogen uniformly, and then entering a reaction system comprising at least one pair of upflow fixed bed reactors and downflow fixed bed reactors connected in series for hydrogenation reaction; the purpose of the system and method is to prepare succinic anhydride, the liquid phase impurity content in the reaction system is low, and it is not proposed to cancel the circulating hydrogen system, and the investment is relatively high.

[0007] CN103789028A discloses a pretreatment method for producing needle coke raw materials using catalytic oil slurry, comprising filtering the catalytic oil slurry and then performing mild hydrogenation treatment, sending 20%-50% (by weight content) of the hydrogenation oil to a vacuum distillation device, and mixing the obtained hydrogenation light fraction oil with the remaining hydrogenation oil as a raw material for producing needle coke; the disadvantage of this method is that the raw material adaptability is poor.

[0008] Therefore, providing a new method and system for hydrogenation treatment of aromatic-rich raw materials has become a technical problem that urgently needs to be solved in the field. Summary of the invention

[0009] In order to solve the above-mentioned shortcomings and deficiencies, an object of the present invention is to provide a method for hydrotreating an aromatic-rich feedstock.

[0010] Another object of the present invention is to provide an aromatic-rich feedstock hydroprocessing system for implementing the above-mentioned aromatic-rich feedstock hydroprocessing method.

[0011] In order to achieve the above objectives, on the one hand, the present invention provides a method for hydrotreating an aromatic-rich raw material, wherein the method for hydrotreating an aromatic-rich raw material comprises:

[0012] Step (1): performing enhanced hydrogen mixing with hydrogen on the aromatics-rich feedstock or the mixture of the aromatics-rich feedstock and the heavy oil fraction to obtain a gas-liquid emulsion flow, wherein the hydrogen is broken into microbubbles during the enhanced hydrogen mixing process and dispersed in the gas-liquid emulsion flow;

[0013] Step (2): allowing the gas-liquid emulsified stream to sequentially pass through an upflow fixed bed reactor and a trickle bed reactor which are connected in series and each of which has a catalyst bed layer, to undergo a hydrogenation reaction to obtain a hydrogenated product; wherein the hydrogenation reaction temperature of the upflow fixed bed reactor is 5-20° C. lower than the hydrogenation reaction temperature of the trickle bed reactor;

[0014] Step (3): performing gas-liquid separation on the hydrogenation product to obtain a gas phase stream and a liquid phase stream;

[0015] Step (4): fractionating the liquid phase stream to obtain a light oil fraction and a heavy oil fraction.

[0016] As a specific embodiment of the above method of the present invention, in step (1), the diameter of the microbubbles is 10-1000 μm.

[0017] As a specific embodiment of the above method of the present invention, the ash content of the aromatic-rich raw material is not higher than 350ppm, and it includes one or a combination of catalytic oil slurry, deasphalted oil, residual oil, furfural extracted oil and ethylene tar. When the ash content of the aromatic-rich raw material is higher than 350ppm, it needs to be desolidified first, and then hydrogenated until the ash content is no higher than 350ppm.

[0018] As a specific embodiment of the method described above in the present invention, the feed port of the upflow fixed bed reactor is arranged at its bottom, and the material in the upflow fixed bed reactor flows through the catalyst bed layer from bottom to top in sequence; the feed port of the trickle bed reactor is arranged at its top, and the material in the trickle bed reactor flows through the catalyst bed layer from top to bottom in sequence. The aromatic-rich raw material hydroprocessing method provided by the present invention returns part of the heavy oil fraction obtained by distillation to the upflow fixed bed reactor as circulating oil, which can be further removed from impurities, greatly reducing the content of impurities such as sulfur, nitrogen, and asphaltene in the product, which is more conducive to using the obtained product as a raw material for producing carbon materials, and the operation can also significantly extend the operation cycle.

[0019] As a specific embodiment of the above method of the present invention, the upflow fixed bed reactor is provided with one or more catalyst beds, and the trickle bed reactor is provided with one or more catalyst beds.

[0020] As a specific embodiment of the method described above, the process conditions of the upflow fixed bed reactor and the trickle bed reactor respectively include: hydrogen partial pressure 2.0-18.0 MPa, preferably 4.0-10.0 MPa; temperature 280-410°C, preferably 300-395°C and volume space velocity of the aromatic-rich raw material 0.1-1.0 h -1 , preferably 0.2-0.6h -1 .

[0021] As a specific embodiment of the method described above, the method further comprises: returning part of the heavy oil fraction in step (4) as circulating oil to the upflow fixed bed reactor. The circulating oil and the gas-liquid emulsified stream may enter the upflow fixed bed reactor separately and be mixed in the upflow fixed bed reactor, or may be mixed outside the upflow fixed bed reactor and then enter the upflow fixed bed reactor together.

[0022] As a specific embodiment of the above method of the present invention, the mass of the heavy oil fraction used as the circulating oil is 20%-80% of the total mass of the heavy oil fraction obtained in step (4).

[0023] As a specific embodiment of the above method of the present invention, in step (4), the heavy oil fraction is a fraction with a temperature ≥ 350°C.

[0024] As a specific embodiment of the method described above, the method further comprises: using the light oil fraction and the heavy oil fraction obtained in step (4) as raw materials to prepare carbon materials, wherein the carbon materials include needle coke, etc.

[0025] In the present invention, the catalyst used in the hydrogenation reaction is not specifically limited, and it is a conventional catalyst. Those skilled in the art can select the type or amount of the catalyst according to actual conditions. For example, the catalyst can be a hydrodesulfurization catalyst, a hydrodenitrogenation catalyst, a hydrodemetallization catalyst, etc. Preferably, the active metal of the catalyst is independently selected from Group VIB metals and / or Group VIII metals; wherein the Group VIB metals are more preferably W and / or Mo; and the Group VIII metals are more preferably Co and / or Ni.

[0026] On the other hand, the present invention also provides an aromatic-rich feedstock hydroprocessing system for realizing the above-mentioned aromatic-rich feedstock hydroprocessing method, wherein the aromatic-rich feedstock hydroprocessing system comprises an enhanced hydrogen mixing unit, an upflow fixed bed reactor, a trickle bed reactor, a gas-liquid separation unit and a fractionation unit which are sequentially connected through pipelines;

[0027] The hydrogenation reaction temperature of the upflow fixed bed reactor is 5-20°C lower than that of the trickle bed reactor.

[0028] As a specific embodiment of the above system of the present invention, the feed inlet of the upflow fixed bed reactor is arranged at the bottom thereof, and the feed inlet of the trickle bed reactor is arranged at the top thereof.

[0029] As a specific embodiment of the above system of the present invention, the heavy oil fraction outlet of the distillation unit is connected to the inlet of the upflow fixed bed reactor through a pipeline, so that part of the heavy oil fraction obtained by distillation of the distillation unit is mixed with the gas-liquid emulsified flow as circulating oil.

[0030] In the present invention, the equipment involved in the enhanced hydrogen mixing unit, the gas-liquid separation unit and the fractionation unit is not specifically limited, and all are commonly used equipment in the field, and those skilled in the art can select or adjust according to actual conditions. For example, the enhanced hydrogen mixing unit can be an enhanced hydrogen mixing unit containing a combination of one or more of a metal tube bundle, a porous ceramic membrane, a venturi tube and a shear pump; the gas-liquid separation unit can be a combination of a conventional high-pressure gas-liquid separator and a conventional low-pressure gas-liquid separator; the fractionation unit can be a stripping tower, a fractionation tower, or a combination of two.

[0031] Compared with the prior art, the aromatics-rich feedstock hydroprocessing method and system provided by the present invention can achieve the following beneficial technical effects:

[0032] (1) The circulating hydrogen system is eliminated, effectively reducing investment costs and hydrogen consumption;

[0033] (2) The liquid phase hydrogenation mode is adopted to reduce the radial temperature difference in the reactor, which is conducive to the long-term stable operation of the system;

[0034] (3) A combination of an upflow fixed bed reactor and a trickle bed reactor is used for hydrogenation reaction. The reaction temperature of the upflow fixed bed reactor is lower than that of the trickle bed reactor, which can effectively prevent the condensation of condensed aromatic hydrocarbons to form coke, inhibit the increase in pressure drop, improve the adaptability of raw materials, and ensure the long-term stable operation of the system. Combined with the liquid phase hydrogenation mode, it can prevent the excessive hydrogenation saturation of tricyclic and tetracyclic aromatic hydrocarbons, which is conducive to using the hydrogenated products as raw materials for preparing carbon materials;

[0035] (4) In summary, the method and system for hydrogenating aromatic-rich raw materials provided by the present invention can treat aromatic-rich raw materials while eliminating the circulating hydrogen system and reducing investment costs and hydrogen consumption, ensuring efficient removal of impurities, while suppressing the oversaturation of aromatics, thereby achieving long-term stable operation of the system, and the products meet the requirements for producing carbon materials such as needle coke. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0037] Figure 1 This is a schematic diagram of the structure of the aromatic-rich feedstock hydroprocessing system provided in Example 1 of the present invention.

[0038] Description of main figures:

[0039] 1: Fufang raw materials;

[0040] 2: Hydrogen;

[0041] 3: Strengthen the hydrogen mixing unit;

[0042] 4: Upflow fixed bed reactor;

[0043] 5: trickle bed reactor;

[0044] 6: Gas-liquid separation unit;

[0045] 7: Fractionation unit;

[0046] 8: Circulating oil. DETAILED DESCRIPTION

[0047] It should be noted that the term "comprises" and any variations thereof in the specification and claims of the present invention and the above-mentioned drawings are intended to cover non-exclusive inclusions. For example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0048] In the present invention, the directions or positional relationships indicated by the terms "upper", "lower", "inner", "outer", "middle", "top" and "bottom" are based on the directions or positional relationships shown in the drawings. These terms are mainly used to better describe the present invention and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific direction, or to be constructed and operated in a specific direction.

[0049] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those skilled in the art, the specific meanings of these terms in the present invention can be understood according to specific circumstances.

[0050] In addition, the terms "disposed" and "connected" should be understood in a broad sense. For example, "connected" can be a fixed connection, a detachable connection, or an integral structure; it can be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be an internal connection between two devices, elements or components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0051] "Scope" disclosed in the present invention is given in the form of lower limit and upper limit. It can be one or more lower limits, and one or more upper limits respectively. A given range is defined by selecting a lower limit and an upper limit. The selected lower limit and upper limit define the boundaries of a particular range. All ranges defined in this way are combinable, i.e. any lower limit can be combined with any upper limit to form a range. For example, for a specific parameter, a range of 60-120 and 80-110 is listed, and it is understood that a range of 60-110 and 80-120 is also expected. In addition, if the minimum range values ​​listed are 1 and 2, and the maximum range values ​​listed are 3, 4 and 5, then the following ranges can all be expected: 1-3, 1-4, 1-5, 2-3, 2-4 and 2-5.

[0052] In the present invention, unless otherwise specified, the numerical range "ab" represents an abbreviation of any real number combination between a and b, where a and b are real numbers. For example, the numerical range "0-5" means that all real numbers between "0-5" have been listed in the present invention, and "0-5" is just an abbreviation of these numerical combinations.

[0053] In the present invention, unless otherwise specified, all embodiments and preferred embodiments mentioned in the present invention can be combined with each other to form a new technical solution.

[0054] In the present invention, unless otherwise specified, all technical features and preferred features mentioned in the present invention can be combined with each other to form a new technical solution.

[0055] In the present invention, unless otherwise specified, all steps mentioned herein may be performed sequentially or randomly, but are preferably performed sequentially. For example, the method includes steps (a) and (b), which means that the method may include steps (a) and (b) performed sequentially, or may include steps (b) and (a) performed sequentially. For example, the method may further include step (c), which means that step (c) may be added to the method in any order, for example, the method may include steps (a), (b) and (c), or may include steps (a), (c) and (b), or may include steps (c), (a) and (b), etc.

[0056] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the attached table, drawings and examples. The following described embodiments are some embodiments of the present invention, rather than all embodiments, and are only used to illustrate the present invention, and should not be regarded as limiting the scope of the present invention. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present invention. If the specific conditions are not specified in the embodiments, they are carried out according to the normal conditions or the conditions recommended by the manufacturer. If the manufacturer is not specified in the reagents or instruments used, they are all conventional products that can be purchased commercially.

[0057] Example 1

[0058] This embodiment provides a system for hydrogenating aromatic raw materials, and its structural schematic diagram is as follows: Figure 1 As shown, from Figure 1 As can be seen, the system comprises:

[0059] An enhanced hydrogen mixing unit 3, an upflow fixed bed reactor 4, a trickle bed reactor 5, a gas-liquid separation unit 6 and a fractionation unit 7; wherein the enhanced hydrogen mixing unit 3 is provided with a hydrogen inlet, an aromatic-rich raw material inlet and an outlet, the upflow fixed bed reactor 4 and the trickle bed reactor 5 are respectively provided with a feed port and a discharge port, and the feed port and the discharge port of the upflow fixed bed reactor 4 are respectively arranged at the bottom and the top thereof, the feed port and the discharge port of the trickle bed reactor 5 are respectively arranged at the top and the bottom thereof, the gas-liquid separation unit 6 includes a feed port and a liquid phase outlet, and the fractionation unit 7 includes a feed port, a light oil fraction outlet and a heavy oil fraction outlet;

[0060] The heavy oil fraction outlet of the fractionation unit 6 is connected to the feed port of the upflow fixed bed reactor 4 through a pipeline, the aromatic-rich feedstock 1 and part of the heavy oil fraction as the circulating oil 8 enter the enhanced hydrogen mixing unit 3 through the aromatic-rich feedstock inlet, the hydrogen 2 enters the enhanced hydrogen mixing unit 3 through the hydrogen inlet, the outlet of the enhanced hydrogen mixing unit 3 is connected to the feed port of the upflow fixed bed reactor 4 through a pipeline, the discharge port is connected to the feed port of the trickle bed reactor 5 through a pipeline, the discharge port is connected to the feed port of the gas-liquid separation unit 6 through a pipeline, and the liquid phase outlet is connected to the feed port of the fractionation unit 7 through a pipeline.

[0061] In this embodiment, the enhanced hydrogen mixing unit 3 can be an enhanced hydrogen mixing unit comprising a combination of one or more of a metal tube bundle, a porous ceramic membrane, a venturi tube and a shear pump; the gas-liquid separation unit 6 can be a combination of a conventional high-pressure gas-liquid separator and a conventional low-pressure gas-liquid separator; the distillation unit 7 can be a stripping tower, a distillation tower, or a combination of both.

[0062] Example 2-Example 6

[0063] This embodiment 2 to embodiment 6 provides a method for hydrogenating an aromatic-rich raw material, wherein the method for hydrogenating an aromatic-rich raw material is implemented by using the aromatic-rich raw material hydrogenating treatment system provided in embodiment 1, and comprises:

[0064] Step (1): performing enhanced hydrogen mixing of the aromatic-rich raw material and hydrogen in an enhanced hydrogen mixing unit 3 to obtain a gas-liquid emulsion flow; during the enhanced hydrogen mixing process, the hydrogen is broken into microbubbles and dispersed in the gas-liquid emulsion flow, wherein the diameter of the microbubbles is 10-1000 μm;

[0065] Step (2): the gas-liquid emulsified stream passes through an upflow fixed bed reactor 4 and a catalyst bed therein from bottom to top, and then passes through a trickle bed reactor 5 and a catalyst bed therein from top to bottom to undergo a hydrogenation reaction, thereby obtaining a hydrogenated product; wherein the upflow fixed bed reactor is filled with a hydrogenation protective agent and a hydrogenation pretreatment agent, and the hydrogenation protective agent is sequentially filled with PHR-401, PHR-402, PHR-403 and PHR-404 according to the flow direction of the material, and the hydrogenation pretreatment agent is sequentially filled with PHR-103 and PHR-201, and the trickle bed reactor is filled with a hydrogenation pretreatment agent and a hydrogenation finishing agent, and the hydrogenation pretreatment agent is sequentially filled with PHR-103 and PHR-201 according to the flow direction of the material, and the hydrogenation finishing agent is filled with PHR-301;

[0066] Step (3): performing gas-liquid separation on the hydrogenation product in a gas-liquid separation unit 6 to obtain a gas phase stream and a liquid phase stream;

[0067] Step (4): fractionating the liquid phase stream in the fractionation unit 7 to obtain a light oil fraction and a heavy oil fraction, wherein the heavy oil fraction is a fraction with a temperature ≥ 350° C. Part of the heavy oil fraction is mixed with the gas-liquid emulsified stream as circulating oil and then enters the upflow fixed bed reactor 4 together.

[0068] Comparative Example 1

[0069] The present comparative example provides a method for hydrogenating an aromatic-rich feedstock, which adopts two conventional trickle bed reactors connected in series, wherein the catalyst loaded in the first trickle bed reactor and the second trickle bed reactor, the reaction pressure, the reaction temperature, the volume space velocity of the aromatic-rich feedstock, and the mass ratio of the circulating oil to the heavy oil fraction are respectively the same as those of the upflow fixed bed reactor and the trickle bed reactor in Example 2, except that the system used in the comparative example 1 contains a circulating hydrogen system, the continuous phase in the two conventional trickle bed reactors connected in series is gas, the dispersed phase is liquid, and the hydrogen-to-oil volume ratio is 1200 V / V.

[0070] Comparative Example 2

[0071] This comparative example provides a method for hydrogenating an aromatic-rich raw material, which differs from Example 3 only in that:

[0072] The hydrogenation reaction temperature of the upflow fixed bed reactor is different from that of the trickle bed reactor, and the former is higher.

[0073] Comparative Example 3

[0074] This comparative example provides a method for hydrogenating an aromatics-rich raw material, wherein the method differs from Example 6 only in that:

[0075] The upflow fixed bed reactor was replaced by a trickle bed reactor.

[0076] Comparative Example 4

[0077] This comparative example provides a method for hydrogenating an aromatic-rich raw material, which differs from Example 2 only in that:

[0078] Part of the heavy oil fraction is not returned to the upflow fixed bed reactor as circulating oil.

[0079] The sources of the materials mainly involved in Examples 2 to 6 of the present invention and Comparative Examples 1 to 4 are shown in Table 1 below, and other unspecified materials are conventional commercially available products.

[0080] Table 1 Material source description

[0081]

[0082]

[0083] The main properties of the raw materials and the operating conditions used in Examples 2 to 6 of the present invention and Comparative Examples 1 to 4 are shown in Tables 2 and 3, respectively. The evaluation results are shown in Table 4. The experimental data in Table 4 are average values.

[0084] Table 2 Main properties of raw materials

[0085]

[0086] Table 3 Process operating conditions

[0087]

[0088]

[0089] Table 4 Evaluation results

[0090]

[0091] By comparing the experimental data in Tables 1 to 4, it can be seen that under conditions where the product properties are substantially the same, the operating cycle of Example 1 using the system and method provided by the present invention is more than twice the operating cycle of Comparative Example 1 using two conventional trickle bed reactors in series;

[0092] In approximately the same operation cycle, using the same raw materials and the same process flow, when the process conditions are different, that is, the hydrogenation reaction temperature of the upflow fixed bed reactor is different from the hydrogenation reaction temperature of the trickle bed reactor, specifically, the hydrogenation reaction temperature of the upflow fixed bed reactor in Example 3 is 10°C lower than that of the trickle bed reactor, and the hydrogenation reaction temperature of the upflow fixed bed reactor in Comparative Example 2 is 20°C higher than that of the trickle bed reactor, compared with Comparative Example 2, the content of impurities such as sulfur, nitrogen, and asphaltene in the product of Example 3 is equivalent, but the loss of aromatics is less;

[0093] The only difference between Comparative Example 3 and Example 6 is that the upflow fixed bed reactor in Example 6 is replaced by a trickle bed reactor, that is, two trickle bed reactors connected in series are used in Comparative Example 3. Compared with Example 6, the aromatics loss in Comparative Example 3 is greater and the operation cycle is shorter;

[0094] The only difference between Comparative Example 4 and Example 2 is that in Comparative Example 4, part of the heavy oil fraction is not returned to the upflow fixed bed reactor as circulating oil. Compared with Example 2, the content of impurities such as sulfur, nitrogen, and asphaltene in the product of Comparative Example 4 is greatly increased, and the operation cycle is significantly shortened.

[0095] In summary, the aromatic-rich feedstock hydroprocessing method and system provided by the present invention are not only conducive to the long-term operation of the system, but also can effectively remove impurities contained in the feedstock while suppressing the oversaturation of aromatic hydrocarbons.

[0096] Application Example 1

[0097] This application example uses the products obtained after hydrogenation of the aromatic-rich raw materials in Example 2, Example 4 and Example 6, namely the light oil fraction and the heavy oil fraction, as raw materials to carry out needle coke preparation tests, and examines the properties of the calcined needle coke products, specifically including:

[0098] The raw materials were loaded into an autoclave coking reactor and the pressure was controlled at 0.8 MPa. When the temperature reached 410°C, the temperature was increased at a rate of 5°C / h. When the temperature reached 490°C, the temperature was increased at a rate of 10°C / h. The temperature was increased to 520°C and kept constant for 2 hours until the coking test was completed. The coke product was taken out and calcined at 1400°C for 4 hours to obtain forged needle coke, which were numbered S-1, S-2 and S-3. The property results are shown in Table 5 below.

[0099] Comparative application example 1

[0100] In this comparative application example, the raw material used in Example 2 is first desolidified until the ash content in the raw material is within 100 ppm, but it is not subjected to hydrogenation treatment. The desolidified raw material is then used as a comparative raw material for a needle coke preparation test, and the properties of the calcined needle coke product are examined, including:

[0101] The comparative raw materials were loaded into an autoclave reactor, the pressure was controlled at 0.8 MPa, variable temperature control was adopted, the temperature range was 410-490°C, the temperature change rate was 5°C / h, when the temperature rose to 490°C, the temperature was increased at a rate of 10°C / h, the temperature was increased to 520°C and kept constant for 2 hours until the coking test was completed, the obtained coke product was taken out and calcined at 1400°C for 4 hours to obtain forged needle coke, numbered D-1, and the property results are shown in Table 5 below.

[0102] Table 5 Analysis of needle coke product properties

[0103] S-1 S-2 S-3 D-1 <![CDATA[Coefficient of thermal expansion, 10 -6 / °C]]> 1.22 1.11 1.12 2.22 <![CDATA[True density, g / cm 3 > 2.13 2.16 2.12 2.13 Ash, wt% 0.09 0.07 0.06 0.17 Volatile matter, wt% 0.22 0.22 0.23 0.25

[0104] As can be seen from Table 5, compared with the forged needle coke product D-1, the thermal expansion coefficients of the forged needle cokes S-1, S-2 and S-3 prepared by using the product obtained by hydrogenating the aromatic-rich raw material in the embodiment of the present invention as the raw material are greatly reduced, the ash content is lower, and the true density and volatile matter are equivalent. This shows that the product obtained by hydrogenating the aromatic-rich raw material in the present invention can be used as a high-quality raw material for preparing graphite electrodes and / or negative electrode materials.

[0105] The above is only a specific embodiment of the present invention, and cannot be used to limit the scope of the invention. Therefore, the replacement of equivalent components, or equivalent changes and modifications made according to the protection scope of the patent of the present invention, should still fall within the scope of this patent. In addition, the technical features of the present invention can be freely combined with each other, with each other and with each other, and with each other.

Claims

1. A method for hydrogenating an aromatics-rich raw material, It is characterized in that The aromatics-rich feedstock hydroprocessing method comprises: Step (1): performing enhanced hydrogen mixing with hydrogen on the aromatics-rich feedstock or the mixture of the aromatics-rich feedstock and the heavy oil fraction to obtain a gas-liquid emulsion flow, wherein the hydrogen is broken into microbubbles during the enhanced hydrogen mixing process and dispersed in the gas-liquid emulsion flow; Step (2): allowing the gas-liquid emulsified stream to sequentially pass through an upflow fixed bed reactor and a trickle bed reactor which are connected in series and each of which has a catalyst bed layer, to undergo a hydrogenation reaction to obtain a hydrogenated product; wherein the hydrogenation reaction temperature of the upflow fixed bed reactor is 5-20° C. lower than the hydrogenation reaction temperature of the trickle bed reactor; Step (3): performing gas-liquid separation on the hydrogenation product to obtain a gas phase stream and a liquid phase stream; Step (4): fractionating the liquid phase stream to obtain a light oil fraction and a heavy oil fraction.

2. The method according to claim 1, It is characterized in that The ash content of the aromatic-rich raw material is not higher than 350 ppm, and the aromatic-rich raw material includes one or a combination of catalytic oil slurry, deasphalted oil, residual oil, furfural extracted oil and ethylene tar.

3. The method according to claim 1, It is characterized in that The feed inlet of the upflow fixed bed reactor is arranged at the bottom thereof, and the feed inlet of the trickle bed reactor is arranged at the top thereof.

4. The method according to claim 1 or 3, It is characterized in that The upflow fixed bed reactor is provided with one or more catalyst beds, and the trickle bed reactor is provided with one or more catalyst beds.

5. The method according to claim 1, It is characterized in that The process conditions of the upflow fixed bed reactor and the trickle bed reactor include: hydrogen partial pressure 2.0-18.0 MPa, temperature 280-410°C and volume space velocity of the aromatic-rich raw material 0.1-1.0 h -1 .

6. The method according to claim 1, It is characterized in that The method further comprises: returning part of the heavy oil fraction in step (4) as circulating oil to the upflow fixed bed reactor.

7. The method according to claim 6, It is characterized in that The mass of the heavy oil fraction used as circulating oil is 20% to 80% of the total mass of the heavy oil fraction obtained in step (4).

8. The method according to any one of claims 1, 6-7, It is characterized in that In step (4), the heavy oil fraction is a fraction with a temperature ≥ 350°C.

9. The method according to claim 1, It is characterized in that The method further comprises: using the light oil fraction and the heavy oil fraction obtained in step (4) as raw materials to prepare carbon materials.

10. An aromatic-rich feedstock hydroprocessing system for implementing the aromatic-rich feedstock hydroprocessing method according to any one of claims 1 to 9, It is characterized in that The aromatics-rich feedstock hydroprocessing system comprises an enhanced hydrogen mixing unit, an upflow fixed bed reactor, a trickle bed reactor, a gas-liquid separation unit and a fractionation unit which are sequentially connected through pipelines; The hydrogenation reaction temperature of the upflow fixed bed reactor is 5-20°C lower than that of the trickle bed reactor.

11. The system according to claim 10, It is characterized in that The feed inlet of the upflow fixed bed reactor is arranged at the bottom thereof, and the feed inlet of the trickle bed reactor is arranged at the top thereof.

12. The system according to claim 10 or 11, It is characterized in that The heavy oil fraction outlet of the fractionation unit is connected to the inlet of the upflow fixed bed reactor through a pipeline.

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