A method and system for producing mesophase pitch

Abstract

This invention provides a method and system for producing mesophase asphalt. The method for producing mesophase asphalt includes the following steps: (1) heat-treating a hydrocarbon-containing raw material, and separating the reaction products to obtain a light component, an intermediate component, and a heavy component; (2) the intermediate component enters a thermal polymerization reaction unit A for reaction, and separating the reaction products to obtain a light stream and a heavy stream; (3) the heavy stream enters a thermal polymerization reaction unit B for reaction, and separating the reaction products to obtain a liquid stream A and an asphalt-containing stream A; (4) the liquid stream A is separated to obtain a liquid stream B and an asphalt-containing stream B; (5) the asphalt-containing stream A is devolatilized to obtain mesophase asphalt. The production method can improve the anisotropic structure content and uniformity of mesophase asphalt, and solve the problem of poor spinnability of mesophase asphalt in the prior art.

Description

Technical Field

[0001] This invention belongs to the field of petrochemical technology and relates to a method and system for producing carbon-containing materials, particularly a method for producing mesophase pitch. Background Technology

[0002] Mesophase pitch is a precursor for many carbon materials, especially a key raw material for the production of pitch-based carbon fibers. Currently, the main production methods for mesophase pitch include the following: (1) direct thermal polycondensation, (2) potential mesophase method, (3) pre-mesophase method, and (4) catalytic modification method. Among them, the direct thermal polycondensation method has a simple production process and is conducive to large-scale industrial production.

[0003] Patent CN112552946A discloses a method for preparing mesophase asphalt, in which raw material A is subjected to primary polymerization in an inert atmosphere at 380℃-420℃ to obtain material B; then material B is subjected to secondary polymerization in an inert atmosphere at 380℃-420℃ to obtain material C; and then material C is subjected to maturation reaction in an inert atmosphere at 320℃-360℃ to obtain mesophase asphalt.

[0004] Patent CN114854444A discloses a method for preparing mesophase pitch using coal / heavy oil hydrorefining residue. The method involves using toluene-soluble material from the coal / heavy oil hydrorefining residue as raw material, and subjecting it to a thermal polycondensation reaction at 380℃~420℃, initial pressure 0MPa~3MPa, reaction time 3~8 hours, and the addition of 5%~15% by mass of a co-carbonizing agent. This yields a pre-mesophase pitch with a mesophase content of 30%~45%. The pre-mesophase pitch is then subjected to thermal settling treatment at 320℃~360℃ for 3~6 hours to obtain mesophase pitch with a mesophase content greater than 95%.

[0005] The content and uniformity of anisotropic microstructures have a direct impact on the overall performance of carbon materials. Therefore, increasing the content of anisotropic microstructures in mesophase pitch, improving stability, and reducing production costs are urgent problems that need to be solved. Summary of the Invention

[0006] To address the problems existing in current mesophase pitch production processes, the core of this invention is to provide a method and system for producing mesophase pitch. This method can increase the content and uniformity of anisotropic microstructure in mesophase pitch, thereby improving its spinnability. This solves the problem of poor spinnability in existing technologies for mesophase pitch.

[0007] The technical solution of this invention mainly includes the following aspects.

[0008] I. This invention first provides a method for producing mesophase pitch, comprising the following steps:

[0009] (1) Under heat treatment conditions, the hydrocarbon-containing raw material is heat-treated, and the reaction products are separated to obtain light components, intermediate components and heavy components;

[0010] (2) The intermediate component enters the thermal polymerization reaction unit A to react, and the reaction products are separated to obtain light material stream and heavy material stream;

[0011] (3) The heavy material stream enters the thermal polymerization reaction unit B to react, and the reaction products are separated to obtain liquid material stream A and asphalt-containing material stream A;

[0012] (4) Separate the liquid phase material flow A obtained in step (3) to obtain liquid phase material flow B and asphalt-containing material flow B;

[0013] (5) After the bituminous material A obtained in step (3) is subjected to devolatilization treatment, mesophase bitumen is obtained.

[0014] In preferred embodiments, the heat treatment process in step (1) involves heat treating the hydrocarbon-containing raw material under certain temperature and pressure conditions. More specifically, the heat treatment temperature is 400℃~550℃, preferably 420℃~490℃, the heat treatment pressure is 0.1MPa~5.0MPa, preferably 0.5MPa~2.0MPa, and the heat treatment time is 20s~3600s, preferably 40s~200s.

[0015] In preferred embodiments, the heat treatment reactor may be one or a combination of several of the following: a batch reactor, a tower reactor, a tubular reactor, etc., with a tubular reactor being preferred.

[0016] In preferred embodiments, the hydrocarbon-containing raw material in step (1) can be selected from at least one of catalytic slurry, ethylene tar, coal tar pitch, etc., preferably catalytic slurry.

[0017] In preferred embodiments, the hydrocarbon-containing raw material in step (1) is preferably subjected to desolidification and / or desulfurization treatment before heat treatment; furthermore, the desolidification treatment can be one or a combination of filtration, centrifugal sedimentation, flocculation sedimentation, etc., preferably filtration, and even more preferably inorganic membrane filtration. The ash content of the hydrocarbon-containing raw material after desolidification treatment is not greater than 80 ppm, preferably not greater than 50 ppm. The desulfurization treatment can be carried out using a hydrodesulfurization process, which can be one or a combination of existing hydrodesulfurization processes such as fixed-bed hydrodesulfurization, suspended-bed hydrodesulfurization, and fluidized-bed hydrodesulfurization, preferably fixed-bed hydrodesulfurization. The hydrodesulfurization catalyst used in the hydrodesulfurization process is a hydrodesulfurization catalyst with desulfurization function. The hydrodesulfurization catalyst includes a support and an active component. The support is generally an inorganic refractory oxide such as alumina; the active component generally includes oxides of Group VIB and / or Group VIII metals. The hydrodesulfurization catalyst can be a commercially available catalyst in the field, such as the FZC and / or FH series hydrodesulfurization catalysts developed by Sinopec (Dalian) Petrochemical Research Institute Co., Ltd. Furthermore, the operating conditions of the hydrodesulfurization process are generally as follows: reaction temperature of 300℃~450℃, preferably 340℃~390℃; reaction pressure of 2MPa~15MPa, preferably 4MPa~8MPa; hydrogen-to-oil volume ratio of 100~2500, preferably 800~1600; and liquid hourly space velocity of 0.1 h⁻¹. -1 ~2.0h -1 Preferably 0.6h -1 ~1.5h -1 The sulfur content of the hydrocarbon-containing feedstock after hydrodesulfurization treatment is no more than 0.5 wt%, preferably no more than 0.4 wt%.

[0018] In a preferred embodiment, the separation of the reaction products in step (1) can be achieved by distillation, preferably by vacuum distillation; the specific vacuum distillation operating conditions can be adjusted according to actual needs, and those skilled in the art know how to determine the operating conditions.

[0019] In preferred embodiments, the 5% distillation temperature of the intermediate component in step (1) is 380°C to 500°C, preferably 420°C to 480°C; the 95% distillation temperature is 520°C to 580°C, preferably 520°C to 550°C.

[0020] In preferred embodiments, the total aromatic hydrocarbon content of the intermediate component in step (1) is 30wt% to 95wt%, preferably 40wt% to 75wt%; the aromatic carbon content is 50wt% to 90wt%, preferably 60wt% to 80wt%; the toluene insoluble content is not greater than 1.0wt%; the quinoline insoluble content is not greater than 0.1wt%; and the ash content is not greater than 20ppm.

[0021] In preferred embodiments, the operating conditions in the thermal polymerization reaction unit A in step (2) are as follows: the reaction temperature is 350℃~480℃, preferably 400℃~460℃; the reaction pressure is 0.2MPa~5.0MPa, preferably 0.5MPa~3.0MPa; and the reaction time is 2h~20h, preferably 5h~15h. Furthermore, the reaction in the thermal polymerization reaction unit A is carried out under thorough stirring conditions. The specific stirring rate can generally be controlled at 50r / min~800r / min, preferably 100r / min~300r / min.

[0022] In preferred embodiments, the 5% distillation temperature of the heavy feed stream in step (2) is 400°C to 500°C, preferably 430°C to 480°C.

[0023] In a preferred embodiment, the softening point of the heavy material flow in step (2) is 60°C to 120°C.

[0024] In preferred embodiments, the toluene-insoluble content of the heavy material stream in step (2) is no more than 20 wt%, preferably no more than 12 wt%, and the quinoline-insoluble content is no more than 5 wt%, preferably no more than 0.5 wt%.

[0025] In preferred embodiments, the operating conditions in the thermal polymerization reaction unit B in step (3) are as follows: the reaction temperature is 350℃~480℃, preferably 400℃~460℃; the reaction pressure is 0MPa~5.0MPa, preferably 0.2MPa~2.0MPa; and the reaction time is 1h~20h, preferably 2h~10h. Furthermore, the reaction in the thermal polymerization reaction unit B is carried out under thorough stirring conditions. The specific stirring rate can generally be controlled at 50r / min~800r / min, preferably 50r / min~300r / min.

[0026] In a preferred embodiment, as some specific implementations, the softening point of the reaction product obtained after the reaction in the thermal polymerization reaction unit B in step (3) is 100℃~270℃, preferably 170℃~240℃.

[0027] In a preferred embodiment, as some specific implementations, the separation in step (3) is sedimentation separation, and the operating conditions for sedimentation separation are: sedimentation temperature of 150℃~400℃, preferably 220℃~330℃, and sedimentation time of 1h~48h, preferably 6h~24h. The sedimentation separation can be carried out in a sedimentation tower.

[0028] In preferred embodiments, based on the weight of the asphalt-containing material flow A, the content of optical anisotropic structure in the asphalt-containing material flow A in step (3) is not less than 60 wt%, preferably not less than 80 wt%.

[0029] In preferred embodiments, based on liquid flow A, the content of optical anisotropic microstructure in liquid flow A in step (3) is no more than 20%, preferably no more than 5 wt%.

[0030] In preferred embodiments, the separation in step (4) is preferably carried out by centrifugal separation. Further centrifugal separation is carried out under an inert atmosphere. The operating temperature of centrifugal separation is 180℃~350℃, preferably 200℃~280℃, and the rotation speed is 1000r / min~10000r / min, preferably 2000r / min~5000r / min. The inert atmosphere can be nitrogen and / or an inert gas, and the inert gas is at least one of helium, neon, argon, and krypton.

[0031] In preferred embodiments, based on liquid flow B, the content of optical anisotropic microstructure in liquid flow B in step (4) is no more than 3%, preferably no more than 0.5 wt%.

[0032] In a preferred embodiment, as some specific implementations, the liquid phase stream B in step (4) can be recycled to the reheat polymerization reaction unit A for reaction.

[0033] In a preferred embodiment, as some specific implementations, the bituminous material stream B in step (4) can be recycled and reacted in the reheat polymerization reaction unit B.

[0034] In a preferred embodiment, the devolatilization process in step (5) is carried out in the presence of a devolatilization atmosphere, which is an atmosphere that does not readily react with the asphalt-containing material stream A; specifically, it can be selected from one or a mixture of several of water vapor, nitrogen, helium, and argon, preferably water vapor and / or nitrogen.

[0035] In preferred embodiments, the operating conditions for the devolatilization treatment in step (5) are as follows: the treatment temperature is 330℃~470℃, preferably 370℃~450℃, the treatment time is 1~15h, preferably 2h~8h, and the flow rate of the devolatilization atmosphere is 1~10L / (min·kg asphalt), preferably 1~5L / (min·kg asphalt).

[0036] In preferred embodiments, the volatile components removed during the devolatilization process in step (5) can be recycled back to step (1) and heat-treated together with the hydrocarbon-containing raw materials.

[0037] A second aspect of the present invention provides a production system for mesophase bitumen, the production system comprising:

[0038] The heat treatment unit includes a heat treatment reactor and a fractionation tower, which is used to receive hydrocarbon-containing raw materials and heat treat them. The reaction products obtained after heat treatment enter the fractionation tower for separation to obtain light components, intermediate components and heavy components.

[0039] Thermal polymerization unit A includes thermal polymerization reaction unit A and separation unit A, which is used to receive intermediate components separated from the fractionation tower in the heat treatment unit. The reaction products are separated by separation unit A to obtain light stream and heavy stream.

[0040] Thermal polymerization unit B includes thermal polymerization reaction unit B and separation unit B, which is used to receive the heavy material stream separated from separation unit A in thermal polymerization unit A, and the reaction products are separated by separation unit B to obtain liquid phase material stream A and asphalt-containing material stream A.

[0041] The centrifugal separation unit is used to receive liquid phase stream A from the second thermal polymerization unit, and after separation, liquid phase stream B and asphalt-containing stream B are obtained;

[0042] The devolatilization unit receives the bituminous material stream A obtained from the separation unit B in the thermal polymerization unit B after separation, and obtains mesophase bitumen after devolatilization treatment.

[0043] In preferred embodiments, the heat treatment reactor may be one or a combination of several of the following: a batch reactor, a tower reactor, a tubular reactor, etc., with a tubular reactor being preferred.

[0044] In preferred embodiments, the fractionation column in the heat treatment unit may be a vacuum distillation column.

[0045] In preferred embodiments, both thermal polymerization reaction unit A and thermal polymerization reaction unit B can be employed as batch reactors, preferably batch reactors equipped with stirring equipment.

[0046] In preferred embodiments, separation unit A may be any one of a fractionation tower, flash tower, stripping tower, etc., with a fractionation tower being preferred.

[0047] In a preferred embodiment, as some specific implementations, the separation in separation unit B is sedimentation separation, which is carried out in a sedimentation tower.

[0048] In a preferred embodiment, the liquid phase stream B obtained from the centrifugal separation unit is connected to the inlet of the thermal polymerization reaction unit A via a pipeline, and the liquid phase stream B enters the thermal polymerization reaction unit A for reaction.

[0049] In a preferred embodiment, as some specific implementations, the asphalt-containing material stream B obtained by the centrifugal separation unit is connected to the inlet of the thermal polymerization reaction unit B via a pipeline, and the asphalt-containing material stream B enters the thermal polymerization reaction unit B for reaction.

[0050] In preferred embodiments, as part of some specific implementations, a separator is provided in the centrifugal separation unit. The separator can be one or more of a centrifugal separator, a centrifugal extractor, a scraper centrifuge, etc., preferably a centrifugal separator.

[0051] In preferred embodiments, the devolatilization unit may be equipped with one or more of the following: a pressure reducing tower, a stripping tower, and a flash tower, with a stripping tower being preferred.

[0052] In preferred embodiments, the volatile components removed by the devolatilization unit are connected to the inlet of the heat treatment reactor of the heat treatment unit via a pipeline, and the volatile components enter the heat treatment reactor for reaction.

[0053] In preferred embodiments, the production system further includes a hydrotreating unit. The hydrocarbon-containing feedstock preferably undergoes hydrodesulfurization treatment in the hydrotreating unit before entering the heat treatment unit. The hydrotreating unit can employ one or a combination of existing hydrotreating processes such as fixed-bed hydrotreating, suspended-bed hydrotreating, and fluidized-bed hydrotreating, with fixed-bed hydrotreating being the preferred method.

[0054] In preferred embodiments, the system also includes a desolidification unit for desolidifying the hydrocarbon-containing feedstock. The hydrocarbon-containing feedstock enters the desolidification unit for desolidification before entering the heat treatment unit (if a hydrogenation treatment unit is provided, the desolidification unit is generally located before the hydrogenation treatment unit). In particular, when the hydrocarbon-containing feedstock is a catalytic slurry, desolidification is generally required. The desolidification unit can employ one or a combination of methods such as filtration, centrifugal sedimentation, and flocculation sedimentation, with filtration being preferred, and inorganic membrane filtration being even more preferred.

[0055] Compared with existing mesophase asphalt production processes, the mesophase asphalt production method and system provided by this invention have one or more of the following technical advantages:

[0056] (1) In the production method of mesophase asphalt provided by the present invention, by setting up a heat treatment reactor, the heavy components with poor thermal stability in the hydrocarbon raw material can be polymerized into macromolecules. The volatile components removed in the devolatilization unit are recycled back to the heat treatment reactor to accelerate the process. Then, the macromolecules formed by polymerization are separated by vacuum distillation and enriched in the heavy components, so that the intermediate components entering the thermal polymerization reaction unit A have better thermal stability and lower solid content, which solves the problem of uneven product due to the difference in thermal reaction performance between the components in the feed.

[0057] (2) In the method for producing mesophase asphalt provided by the present invention, the uniformity of the final mesophase asphalt product can be effectively improved by step-by-step and effectively controlling the polymerization reaction depth of the intermediate components through a two-stage thermal polymerization reaction. After the intermediate components undergo the first-stage thermal polymerization and separation, the light material stream that is not easy to polymerize is removed, avoiding the problem of excessively wide distribution of aromatic molecules in the system due to the difference in thermal reaction progress between the light and heavy material streams; by controlling the softening point and quinoline insoluble content of the heavy material stream, the feed molecular structure of the thermal polymerization reaction unit B is effectively made more concentrated, but without excessive thermal polymerization. In the thermal polymerization reaction unit B, the thermal polymerization depth of the heavy material stream is increased as much as possible, which increases the proportion of anisotropic microstructure while avoiding coke formation.

[0058] (3) In the method for producing mesophase asphalt provided by the present invention, the liquid phase stream A is rich in mesophase microspheres. After centrifugation, the content of optical anisotropic microstructure in the resulting liquid phase stream B is significantly reduced. The liquid phase stream B is returned to the thermal polymerization reaction unit A, which can promote the thermal polymerization reaction of the intermediate components and increase the reaction rate. The asphalt-containing stream B, rich in a large number of mesophase microspheres, is returned to the thermal polymerization reaction unit B. The mesophase microspheres, as nuclei, absorb the surrounding mother liquor and grow continuously, which can greatly shorten the polymerization reaction time of the thermal polymerization reaction unit B.

[0059] (4) In the method for producing mesophase asphalt provided by the present invention, the hydrocarbon-containing raw materials (such as catalytic slurry) are preferably first subjected to hydrogenation treatment. On the one hand, this effectively reduces the sulfur content of the hydrocarbon-containing raw materials, and on the other hand, it increases the number of saturated side chains of aromatic molecules. The thermal stability is greatly improved in the two-stage thermal polymerization reaction, avoiding the problem of uneven system caused by excessively violent local thermal polymerization reaction. Attached Figure Description

[0060] Figure 1 This is a schematic diagram of the process flow for a method of producing mesophase asphalt provided by the present invention.

[0061] Figure 2A schematic diagram of the process flow for another method of producing mesophase bitumen provided by the present invention.

[0062] Figure 3 This is a polarized light microscope image of the asphalt-containing material flow A obtained in Example 1.

[0063] Figure 4 This is a polarized light microscope image of the liquid phase flow A obtained in Example 1.

[0064] Figure 5 This is a polarized light microscope image of the asphalt-containing material flow B obtained in Example 1.

[0065] Figure 6 This is a polarized light microscope image of the liquid phase flow B obtained in Example 1.

[0066] Figure 7 This is a polarized light microscope image of the mesophase pitch sample obtained in Example 1.

[0067] Figure 8 This is a polarized light microscope image of the mesophase pitch sample obtained in Comparative Example 1.

[0068] Figure 9 This is a polarized light microscope image of the mesophase pitch sample obtained in Comparative Example 2.

[0069] Figure 10 This is a polarized light microscope image of the mesophase pitch sample obtained in Example 2.

[0070] Figure 11 This is a polarized light microscope image of the mesophase pitch sample obtained in Example 3.

[0071] Figure 12 This is a polarized light microscope image of the mesophase pitch sample obtained in Comparative Example 3. Detailed Implementation

[0072] The specific embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but it should be understood that the scope of protection of the present invention is not limited to the specific embodiments.

[0073] 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.

[0074] In this document, for ease of description, spatial relative terms such as “below,” “under,” “down,” “above,” “above,” “upper,” etc., are 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, in addition to 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” that 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.

[0075] In this document, the terms "first," "second," etc., are used to distinguish two different elements or parts, and are not used to define specific positions or relative relationships. In other words, in some embodiments, the terms "first," "second," etc., can also be used interchangeably.

[0076] In this document, all numeric values ​​of parameters (e.g., quantity or condition) should be understood to be modified by the term “about” in all cases, regardless of whether “about” actually appears before the numeric value.

[0077] In this paper, sulfur content was determined by GB / T387 method; total aromatic hydrocarbon content was determined by SH / T0509 method; aromatic carbon content was determined by SH / T0793 method; ash content was determined by GB / T508 method; bitumen softening point was determined by ASTMD 3461 method; toluene insoluble matter was determined by GB / T2292 method; quinoline insoluble matter was determined by GB / T2293 method; and the proportion of anisotropic microstructure was determined by YB / T 077 method.

[0078] like Figure 1As shown, the process flow of the mesophase asphalt production method provided by the present invention is as follows: the hydrocarbon-containing raw material 1 can optionally enter the desolidification treatment unit 2 for desolidification treatment, and the hydrocarbon-containing raw material 12 obtained after desolidification treatment can optionally enter the hydrotreating unit 3 to undergo hydrodesulfurization reaction under the action of hydrodesulfurization catalyst. The hydrotreating reaction effluent 13 enters the heat treatment reactor 4 for heat treatment reaction, and the heat treatment reaction product 14 enters the fractionation tower 5. After separation, light component 16, intermediate component 15 and heavy component 17 are obtained. In this process, intermediate component 15 enters thermal polymerization reaction unit A6 to undergo a first-stage thermal polymerization reaction. The product 18 from the first-stage thermal polymerization reaction enters separation unit A7, where it is separated to obtain light material stream 20 and heavy material stream 19. The heavy material stream 19 is then sent to thermal polymerization reaction unit B8 to undergo a second-stage thermal polymerization reaction. The product 21 from the second-stage thermal polymerization reaction enters settling tower 9 and is separated by settling to obtain liquid phase stream A23 and asphalt-containing stream A22. Liquid phase stream A23 further enters centrifugal separation unit 26 and is separated by centrifugation to obtain liquid phase stream B27 and asphalt-containing stream B28. Liquid phase stream B27 can be circulated back to thermal polymerization reaction unit A6 via pipeline, and asphalt-containing stream B28 can be circulated back to thermal polymerization reaction unit B8 via pipeline. The asphalt-containing material stream A22 is contacted with the devolatilization atmosphere 11 in the devolatilization unit 10 to remove the volatile components 24 and obtain mesophase asphalt 25. The volatile components 24 can be returned to the heat treatment reactor 4 via pipeline.

[0079] The hydrocarbon-containing feedstock used in the embodiments and comparative examples of this invention is catalytic slurry oil. The specific properties of the catalytic slurry oil after solidification treatment are shown in Table 1. The hydrogenation catalyst used in the hydrogenation unit is the FZC-34BT hydrogenation catalyst developed by Sinopec (Dalian) Petrochemical Research Institute Co., Ltd.

[0080] Example 1

[0081] Example 1 uses Figure 1 The process route provided describes a method where, after solidification treatment, the catalytic slurry sequentially passes through a hydrotreating unit, a thermal treatment reactor, and a fractionation tower to obtain an intermediate component. The intermediate component is then sequentially separated into a heavy stream by a thermal polymerization reaction unit A and a separation unit A. The heavy stream then passes through a thermal polymerization reaction unit B and a settling tower to obtain a liquid stream A and a bitumen-containing stream A. Liquid stream A is separated into liquid stream B and bitumen-containing stream B by a centrifugal separation unit. Liquid stream B is recycled back to thermal polymerization reaction unit A, and bitumen-containing stream B is also recycled back to thermal polymerization reaction unit B. Bitumen-containing stream A undergoes a devolatilization unit to remove volatile components, yielding mesophase bitumen.

[0082] The operating conditions of the hydrogenation unit are listed in Table 2.

[0083] The operating conditions of the heat treatment reactor, thermal polymerization reaction unit A, thermal polymerization reaction unit B, settling tower, centrifugal separation unit, and devolatilization unit are listed in Table 3, and the properties of the main intermediate products and mesophase asphalt of each unit are listed in Table 4.

[0084] Comparative Example 1

[0085] The process route in Comparative Example 1 is the same as that in this invention. Figure 1 The main difference in the process route is that there is no heat treatment reactor, and the hydrogenation reaction effluent directly enters the fractionation tower for separation to obtain intermediate components.

[0086] The operating conditions of the hydrogenation treatment unit are the same as those in Example 1, and are listed in Table 2.

[0087] The operating conditions of thermal polymerization reaction unit A, thermal polymerization reaction unit B, settling tower, centrifugal separation unit, and devolatilization unit are listed in Table 3, and the properties of the main intermediate products and mesophase asphalt of each unit are listed in Table 4.

[0088] Comparative Example 2

[0089] The main difference between the process route in Comparative Example 2 and the process route of the present invention in Example 2 is that: no centrifugal separation unit is set up, and the liquid phase material flow A is processed in the reheat polymerization reaction unit B.

[0090] The operating conditions of the hydrogenation treatment unit are the same as those in Example 1, and are listed in Table 2.

[0091] The operating conditions of the heat treatment reactor, thermal polymerization reaction unit A, thermal polymerization reaction unit B, settling tower, and devolatilization unit are listed in Table 3, and the properties of the main intermediate products and mesophase asphalt of each unit are listed in Table 4.

[0092] Example 2

[0093] Example 2 adopts Figure 2 The provided process route is basically the same as that in Example 1, with the main difference being that the volatile components removed by the devolatilization unit are recycled back to the heat treatment reactor.

[0094] The operating conditions of the hydrogenation unit are listed in Table 5.

[0095] The operating conditions of thermal polymerization reaction unit A, thermal polymerization reaction unit B, settling tower and devolatilization unit are listed in Table 6, and the properties of the main intermediate products and mesophase bitumen of each unit are listed in Table 7.

[0096] Example 3

[0097] Example 3 uses Figure 2The main difference between the provided process route and Example 2 is that the operating conditions of some reaction units are different, as detailed in Tables 5 and 6. The properties of the main intermediate products and mesophase pitch of each unit are listed in Table 7.

[0098] Comparative Example 3

[0099] The main difference between the process route in Comparative Example 3 and the process route of the present invention in Example 3 is that no pretreatment reactor or centrifugal separation unit is set up.

[0100] The operating conditions of the hydrogenation treatment unit are the same as those in Example 3, and are listed in Table 5.

[0101] The operating conditions of thermal polymerization reaction unit A, thermal polymerization reaction unit B, settling tower and devolatilization unit are listed in Table 6, and the properties of the main intermediate products and mesophase bitumen of each unit are listed in Table 7.

[0102] Table 1 Properties of Catalytic Slurry

[0103] project numerical values Ash content / ppm 46 Sulfur content, wt% 1.27 5% distillation temperature / ℃ 362

[0104] Table 2 Operating conditions of the hydrogenation reaction units in Example 1, Comparative Example 1, and Comparative Example 2

[0105] project numerical values Temperature / °C 360 Pressure / MPa 8.2 Hydrogen-to-oil volume ratio 1200 <![CDATA[Liquid hourly space velocity / h -1 > 0.9

[0106] Table 3 Operating conditions of each reaction unit in Example 1, Comparative Example 1, and Comparative Example 2

[0107]

[0108]

[0109]

[0110] Table 4. Properties of the main intermediate products and mesophase pitch in Examples 1, Comparative Examples 1 and 2

[0111]

[0112]

[0113] Table 5. Operating conditions of the hydrogenation reaction unit in Examples 2, 3, and Comparative Example 3.

[0114] project Example 2 Example 3 Comparative Example 3 Temperature / °C 375 373 373 Pressure / MPa 7.3 7.0 7.0 Hydrogen-to-oil volume ratio 1200 1100 1100 <![CDATA[Liquid hourly space velocity / h -1 > 1.0 1.1 1.1

[0115] Table 6. Operating conditions of each reaction unit in Examples 2, 3, and Comparative Example 3.

[0116]

[0117]

[0118]

[0119] Table 7 Properties of the main intermediate products and mesophase pitch in Examples 2, 3, and Comparative Example 3

[0120]

[0121]

Claims

1. A method for producing mesophase asphalt, comprising the following steps: (1) Under heat treatment conditions, the hydrocarbon-containing raw material is heat-treated, and the reaction products are separated to obtain light components, intermediate components and heavy components; (2) The intermediate components enter the thermal polymerization reaction unit A to react, and the reaction products are separated to obtain light material stream and heavy material stream; (3) The heavy material stream enters the thermal polymerization reaction unit B for reaction, and the reaction products are separated to obtain liquid material stream A and asphalt-containing material stream A; (4) Separate the liquid phase material flow A obtained in step (3) to obtain liquid phase material flow B and asphalt-containing material flow B; (5) After the bituminous material A obtained in step (3) is subjected to devolatilization treatment, mesophase bitumen is obtained.

2. The method for producing mesophase pitch according to claim 1, wherein, The heat treatment temperature in step (1) is 400℃~550℃, preferably 420℃~490℃, the heat treatment pressure is 0.1MPa~5.0MPa, preferably 0.5MPa~2.0MPa, and the heat treatment time is 20s~3600s, preferably 40s~200s.

3. The method for producing mesophase pitch according to claim 1, wherein, The hydrocarbon-containing raw material in step (1) is selected from at least one of catalytic oil slurry, ethylene tar, and coal tar pitch, preferably catalytic oil slurry.

4. The method for producing mesophase pitch according to claim 1 or 3, wherein, Before heat treatment, the hydrocarbon raw material in step (1) is subjected to desolidification and / or desulfurization treatment; the ash content of the hydrocarbon raw material after desolidification treatment is not greater than 80 ppm, preferably not greater than 50 ppm; the sulfur content of the hydrocarbon raw material after hydrodesulfurization treatment is not greater than 0.5 wt%, preferably not greater than 0.4 wt%.

5. The method for producing mesophase pitch according to claim 1, wherein, The 5% distillation temperature of the intermediate component in step (1) is 380℃~500℃, preferably 420℃~480℃; the 95% distillation temperature is 520℃~580℃, preferably 520℃~550℃.

6. The method for producing mesophase pitch according to claim 1, wherein, The total aromatic hydrocarbon content of the intermediate component in step (1) is 30wt% to 95wt%, preferably 40wt% to 75wt%; the aromatic carbon content is 50wt% to 90wt%, preferably 60wt% to 80wt%.

7. A method for producing mesophase pitch according to claim 1 or 6, wherein, The intermediate component in step (1) has a toluene insoluble content of no more than 1.0 wt%, a quinoline insoluble content of no more than 0.1 wt%, and an ash content of no more than 20 ppm.

8. The method for producing mesophase pitch according to claim 1, wherein, The operating conditions in the thermal polymerization reaction unit A in step (2) are as follows: the reaction temperature is 350℃~480℃, preferably 400℃~460℃, the reaction pressure is 0.2MPa~5.0MPa, preferably 0.5MPa~3.0MPa, and the reaction time is 2h~20h, preferably 5h~15h.

9. The method for producing mesophase pitch according to claim 1, wherein, The 5% distillation temperature of the heavy material stream in step (2) is 400℃~500℃, preferably 430℃~480℃; the softening point of the heavy material stream is 60℃~120℃.

10. The method for producing mesophase pitch according to claim 1, wherein, The content of toluene-insoluble matter in the heavy material stream in step (2) is no more than 20 wt%, preferably no more than 12 wt%, and the content of quinoline-insoluble matter is no more than 5 wt%, preferably no more than 0.5 wt%.

11. The method for producing mesophase pitch according to claim 1, wherein, The operating conditions in the thermal polymerization reaction unit B in step (3) are as follows: the reaction temperature is 350℃~480℃, preferably 400℃~460℃, the reaction pressure is 0MPa~5.0MPa, preferably 0.2MPa~2.0MPa, and the reaction time is 1h~20h, preferably 2h~10h.

12. The method for producing mesophase pitch according to claim 1, wherein, The softening point of the reaction product obtained after the reaction in the thermal polymerization reaction unit B in step (3) is 100℃~270℃, preferably 170℃~240℃.

13. The method for producing mesophase pitch according to claim 1, wherein, The separation in step (3) is sedimentation separation. The operating conditions for sedimentation separation are: sedimentation temperature of 150℃~400℃, preferably 220℃~330℃.

14. The method for producing mesophase pitch according to claim 1, wherein, Based on the weight of the asphalt-containing material flow A, the content of optical anisotropic structure in the asphalt-containing material flow A in step (3) shall be not less than 60 wt%, preferably not less than 80 wt%.

15. The method for producing mesophase pitch according to claim 1, wherein, Based on liquid flow A, the content of optical anisotropic structure in liquid flow A in step (3) is no more than 20%, preferably no more than 5 wt%.

16. The method for producing mesophase pitch according to claim 1, wherein, The separation in step (4) is carried out by centrifugal separation under an inert atmosphere. The operating temperature of the centrifugal separation is 180℃~350℃, preferably 200℃~280℃. The inert atmosphere is nitrogen and / or an inert gas, which is at least one of helium, neon, argon and krypton.

17. The method for producing mesophase pitch according to claim 1, wherein, Based on the weight of liquid phase flow B, the content of optical anisotropic microstructure of liquid phase flow B in step (4) is no more than 3wt%, preferably no more than 0.5wt%.

18. The method for producing mesophase pitch according to claim 1, wherein, The liquid phase material flow B in step (4) is recycled and reheated in the polymerization reaction unit A.

19. The method for producing mesophase pitch according to claim 1, wherein, The reaction takes place in the circulating reheat polymerization reaction unit B of the asphalt-containing material flow B in step (4).

20. The method for producing mesophase pitch according to claim 1, wherein, In step (5), the devolatilization process is carried out in the presence of a devolatilization atmosphere, which is an atmosphere that does not readily react with the asphalt-containing material A; it is selected from one or a mixture of several of water vapor, nitrogen, helium, and argon, preferably water vapor and / or nitrogen.

21. The method for producing mesophase pitch according to claim 1, wherein, The operating conditions for the devolatilization treatment in step (5) are as follows: the treatment temperature is 330℃~470℃, preferably 370℃~450℃, the treatment time is 1~15h, preferably 2h~8h, and the flow rate of the devolatilization atmosphere is 1~10L / (min·kg asphalt), preferably 1~5L / (min·kg asphalt).

22. The method for producing mesophase pitch according to claim 1, wherein, The volatile components removed during the devolatilization process in step (5) are recycled back to step (1) and subjected to heat treatment together with the hydrocarbon-containing raw materials.

23. A system for producing mesophase bitumen, the system comprising: The heat treatment unit includes a heat treatment reactor and a fractionation tower, which is used to receive hydrocarbon-containing raw materials and heat treat them. The reaction products obtained after heat treatment enter the fractionation tower for separation to obtain light components, intermediate components and heavy components. Thermal polymerization unit A includes thermal polymerization reaction unit A and separation unit A, which is used to receive intermediate components separated from the fractionation tower in the heat treatment unit. The reaction products are separated by separation unit A to obtain light stream and heavy stream. Thermal polymerization unit B includes thermal polymerization reaction unit B and separation unit B, which is used to receive the heavy material stream separated from separation unit A in thermal polymerization unit A, and the reaction products are separated by separation unit B to obtain liquid phase material stream A and asphalt-containing material stream A. The centrifugal separation unit is used to receive liquid phase stream A from the second thermal polymerization unit, and after separation, liquid phase stream B and asphalt-containing stream B are obtained; The devolatilization unit receives the bituminous material stream A obtained from the separation unit B in the thermal polymerization unit B after separation, and obtains mesophase bitumen after devolatilization treatment.

24. The mesophase bitumen production system according to claim 23, wherein, A heat treatment reactor is one or a combination of several of the following: a batch reactor, a tower reactor, and a tubular reactor, with a tubular reactor being preferred.

25. The mesophase bitumen production system according to claim 22, wherein, Both thermal polymerization reaction unit A and thermal polymerization reaction unit B adopt a batch reactor, preferably a batch reactor with a stirring device.

26. The mesophase bitumen production system according to claim 22, wherein, Separation unit A can be any one of a fractionation tower, flash tower, or stripping tower, with a fractionation tower being preferred.

27. The mesophase bitumen production system according to claim 22, wherein, The separation in separation unit B is sedimentation separation, which is carried out in a sedimentation tower.

28. The mesophase bitumen production system according to claim 22, wherein, The liquid phase stream B obtained from the centrifugal separation unit is connected to the inlet of the thermal polymerization reaction unit A via a pipeline, and the liquid phase stream B enters the thermal polymerization reaction unit A to carry out the reaction.

29. The mesophase bitumen production system according to claim 22, wherein, The asphalt-containing material stream B obtained from the centrifugal separation unit is connected to the inlet of the thermal polymerization reaction unit B via a pipeline, and the asphalt-containing material stream B enters the thermal polymerization reaction unit B to undergo reaction.

30. The mesophase bitumen production system according to claim 22, wherein, The centrifugal separation unit is equipped with a separator, which is one or more of the following: centrifugal separator, centrifugal extractor, and scraper centrifuge, preferably a centrifugal separator.

31. The mesophase bitumen production system according to claim 22, wherein, The devolatilization unit is equipped with one or more of the following: a pressure reducing tower, a stripping tower, and a flash tower, with a stripping tower being preferred.

32. The mesophase bitumen production system according to claim 22, wherein, The volatile components removed from the devolatilization unit are connected to the feed inlet of the heat treatment reactor in the heat treatment unit via pipelines, and the volatile components enter the heat treatment reactor to react.

33. The mesophase bitumen production system according to claim 22, wherein, The production system also includes a hydrogenation unit, where hydrocarbon-containing raw materials undergo hydrodesulfurization treatment before entering the heat treatment unit.

34. The mesophase bitumen production system according to claim 22, wherein, It also includes a desolidification unit for desolidifying hydrocarbon-containing raw materials. The desolidification unit adopts one or a combination of filtration, centrifugal sedimentation, and flocculation sedimentation, preferably filtration, and more preferably inorganic membrane filtration.

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