Systems and methods for producing mesophase carbon from isotropic pitch

Abstract

A system (1000) for producing mesophase coke from isotropic pitch is disclosed. The system comprises a reactor having a first heating zone (102) to pre-treat isotropic pitch by operating at a temperature of 250-350°C at atmospheric pressure. The reactor further comprises a second heating zone (103) to heat the pre-treated isotropic pitch to obtain mesophase pitch by maintaining a temperature of 350-500°C at atmospheric pressure. The reactor comprises a third heating zone (104) to heat the mesophase pitch to obtain mesophase coke by maintaining a temperature of 500-800°C at atmospheric pressure. The system further comprises a pusher unit (300) adapted to physically move a container (50) from an inlet zone (101) to an outlet zone (106) to obtain mesophase coke.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to application number 202021022401, filed on May 28, 2020, the disclosure of which is incorporated herein by reference. Technical Field

[0003] This invention relates to a system and method for producing coke, and more specifically, it discloses a system and continuous method for producing mesophase pitch and mesophase coke from coal / petroleum tar pitch as raw material, wherein the mesophase pitch will be used as a raw material to prepare carbon / graphite electrodes for secondary batteries. Background Technology

[0004] The demand for new materials is a continuous search, with materials possessing highly specific properties requiring specialized manufacturing equipment and simple process control. Carbon materials, due to their numerous properties (mechanical strength and high modulus, low density, high thermal and electrical conductivity, ion intercalation / absorption characteristics, etc.), have found a significant niche in the field of new materials, making them irreplaceable in certain applications. One such application is lithium-ion batteries, where pitch or coke is used as a carbon precursor to manufacture carbon / graphite anodes.

[0005] However, bitumen and coke should be anisotropic in nature and contain a high content of mesophase. Therefore, to overcome this problem, methods for producing mesophase bitumen have emerged. One such method is disclosed in U.S. Patent Publication No. 4,904,371.

[0006] The patent discloses an improved and simplified method for producing carbon-containing bitumen products, wherein the mesophase content of the carbon-containing bitumen product is controlled within the range of approximately 50% to 100%. The method involves heating a carbonaceous feedstock that is substantially free of mesophase bitumen at a temperature above 350°C under atmospheric pressure for approximately 6 hours.

[0007] The method further includes subjecting the carbonaceous feedstock to hot soaking for up to 10 additional hours in the absence of jet gas within a temperature range of 250°C to 350°C. Furthermore, the pretreated carbonaceous feedstock is subsequently reheated for up to 10 hours in the presence of non-oxidizing jet gas within a temperature range of 350°C to 500°C to form mesophase pitch.

[0008] However, it has been observed that the heat treatment time in the above process is as long as 20 to 30 hours. Furthermore, inert gas is used in the aforementioned covering process. Since the inert gas is only used for covering, the process consumes a relatively small amount of gas, approximately 0.25 cubic feet per hour (SCFH) / lb, thereby reducing energy consumption.

[0009] Furthermore, a similar method is disclosed in U.S. Patent Publication No. 4,551,225. That patent discloses an improved method for preparing optically anisotropic pitch, comprising heating a pitch feed at a temperature in the range of about 350°C to 450°C while passing an inert gas through the pitch feed at a rate of at least 2.5 standard cubic feet per hour (SCFH) per pound of pitch feed, and then agitating the pitch feed at a stirring rate of about 500 to 600 rpm to obtain a substantially 100% mesophase pitch product suitable for carbon production.

[0010] However, it has been found that the processing time and inert gas flow rate for producing anisotropic asphalt are very high in the above methods. Furthermore, this process requires high-speed agitator equipment and only produces mesophase asphalt.

[0011] Furthermore, another similar method for producing mesophase pitch is disclosed in U.S. Patent Publication No. 4,631,181. This method involves producing the mesophase by adding at least one of an alcohol and a phenol to heavy pitch. Additionally, the process includes pretreating the mixture at a temperature of at least 250°C, followed by heat treatment of the pretreated mixture.

[0012] However, it should be noted that the above method requires additives and high pressure to produce mesophase asphalt, and furthermore, it does not produce fully anisotropic asphalt.

[0013] U.S. Patent Publication No. 4,704,333 discloses another method for producing mesophase pitch. The method includes converting pitch into mesophase pitch in the presence of catalytically effective amounts of oxides of metals selected from vanadium, chromium, molybdenum, iron, nickel, and cobalt, diketones, carboxylates, and carbonyl groups.

[0014] Another method for producing mesophase pitch is disclosed in U.S. Patent Publication No. 5,182,010. The method comprises polymerizing a naphthalene derivative having at least one methyl group for about 5 to 300 minutes at a temperature of about 180°C to 400°C and a pressure of about 5 to 100 atm per mole of naphthalene derivative, in the presence of about 0.1 to 20 moles of hydrogen fluoride (HF) and about 0.05 to 1.0 moles of boron trifluoride (BF3).

[0015] However, it should be noted that a catalyst is used in the above method; therefore, a certain percentage of the metal catalyst may remain in the produced mesophase pitch, thus compromising purity. Furthermore, the process requires a high-pressure vessel, which increases capital expenditure and processing costs.

[0016] U.S. Patent Publication No. 4,512,874 discloses another method for producing a mesophase. The method includes heat-treating petroleum bitumen at a temperature of 360°C to 450°C. Subsequently, the heat-treated bitumen is transferred to a mesophase growth and coagulation step.

[0017] The method further includes heat-treated bitumen transferred during the mesophase growth and coalescence steps, whereby only the mesophase grows and coalesces by aging at temperatures above 280°C and below 350°C. Finally, the method includes removing the mesophase, consisting of QI and QS components, from the lower layer during the growth and coalescence steps.

[0018] However, the above method requires two containers: one for the formation of the mesophase and the other for its growth and aggregation. Furthermore, the isotropic material returns to the first container after separation. Therefore, it is difficult to transfer very viscous materials from one container to another.

[0019] Furthermore, U.S. Patent Publication No. 2,775,549 discloses a method for producing needle coke. The method includes removing components from high-boiling-point petroleum residue oil by heating to 350°C to 550°C, followed by coking the remaining residue oil in a settling tank.

[0020] U.S. Patent No. 9,777,221 also discloses a semi-continuous method for producing needle coke for low coefficient of thermal expansion (CTE) graphite electrodes. The method includes heating a needle coke precursor under pressure, thereby converting 60% to 90% of the coal tar distillate into raw coke. The method then calcines the raw coke to produce needle coke with a low coefficient of thermal expansion.

[0021] However, the above process requires approximately 2 kg / cm². 2 Up to 7kg / cm 2 The system requires high pressure. Therefore, it necessitates an expensive coking drum. Furthermore, high-pressure water jets are used to remove the needle-like coke formed in the drum, and subsequent treatment is required to remove water from the produced coke.

[0022] Another such method is disclosed in U.S. Patent Publication No. 4,219,405. This patent discloses the continuous production of coke. The method includes preheating hydrocarbons and recycling condensate at a rate that increases the mesophase content of the mixture to 30% to 60%. The method also includes heating the preheated mixture at a certain rate in a coking zone to form green coke with a mesophase content of 70% to 100%. Then, following this process, the green coke is continuously removed from the coking zone, and the removed coke is heated in a calcining furnace.

[0023] However, it should be noted that the raw asphalt needs to have a mesophase content of 30-60% before entering the coking zone, which requires additional equipment to manufacture the raw asphalt.

[0024] Therefore, there is a need for a system and a simple method for producing controlled mesophase coke that eliminates the need for high-temperature pumps to deliver viscous bitumen and high-pressure processes to reduce equipment costs and ease of operation.

[0025] In addition, there is a need for systems and methods for producing mesophase coke that can eliminate the need for organic solvents, additives or catalysts.

[0026] In addition, systems and methods are needed to reduce the processing time for producing mesophase coke.

[0027] In short, there is a need for systems and methods for producing mesophase coke that can overcome the aforementioned drawbacks and provide an easy-to-operate and cost-effective approach. Summary of the Invention

[0028] Therefore, aspects of the present invention relate to systems and methods for producing mesophase coke from isotropic pitch. Both systems and methods are cost-effective and overcome existing problems by providing high-quality mesophase coke.

[0029] In one aspect of the invention, a system for producing mesophase coke from isotropic pitch is provided. The system includes a reactor comprising an inlet area having a container adapted to receive the isotropic pitch.

[0030] The reactor further includes a first heating zone adapted to pretreat the isotropic asphalt by operating the first heating zone at a temperature of 250°C to 350°C under atmospheric pressure. Furthermore, the reactor includes a second heating zone adapted to heat the pretreated isotropic asphalt by maintaining a temperature of 350°C to 500°C under atmospheric pressure to convert the isotropic asphalt into mesophase asphalt.

[0031] The reactor further includes a third heating zone adapted to heat the mesophase pitch at a temperature maintained at atmospheric pressure of 500°C to 800°C to obtain mesophase coke. Additionally, the reactor includes a cooling zone to cool the product from a high temperature to a low temperature. Furthermore, the reactor includes an outlet zone adapted to discharge the mesophase coke from the reactor.

[0032] The system also includes a controlled-speed actuator unit adapted to physically move the container at a controlled speed from the inlet zone to the first heating zone, the second heating zone, and the third heating zone through the outlet zone to obtain mesophase coke in the outlet zone. This eliminates the need to install an expensive pumping system to pump high-viscosity bitumen 10 from one reactor to another at high temperatures.

[0033] In one embodiment of the invention, the isotropic pitch is selected from at least one of coal tar or petroleum tar. The softening point (SP) temperature of the isotropic pitch is 80°C to 120°C, and the quinoline insoluble (QI) content is less than or equal to 2%.

[0034] In another embodiment of the invention, the system further includes a reservoir adapted to contain the isotropic bitumen and to supply the isotropic bitumen into the container.

[0035] In one embodiment of the invention, the reactor further includes a cooling zone adapted to cool the mesophase coke obtained from the third heating zone.

[0036] In another embodiment of the invention, the system further includes a pulverizing unit adapted to pulverize the mesophase coke into coke particles.

[0037] In one embodiment of the invention, the system further includes a hopper adapted to store the coke particles.

[0038] In addition, the system includes a pneumatic conveying system for conveying the coke particles from the crushing unit to the hopper.

[0039] The system also includes a vapor condensation unit and an oil storage unit, which are adapted to condense the asphalt evaporated from the system to obtain condensed oil.

[0040] One object of the present invention is to disclose a method for producing mesophase coke from isotropic pitch. The method includes adding anisotropic pitch into a container placed in the inlet zone of a reactor. The process is then followed by physically moving the container to a first heating zone via a pusher unit, wherein the container moves in a straight line within the reactor.

[0041] The method further includes physically moving the container from the first heating zone to a second heating zone via the actuator unit. The pretreated isotropic bitumen is heated in the second heating zone of the reactor, maintaining the temperature at atmospheric pressure between 350°C and 500°C to obtain mesophase bitumen.

[0042] Furthermore, the method includes physically moving the container from the second heating zone to a third heating zone via the actuator unit. Following this process, the mesophase pitch is heated within the third heating zone of the reactor by maintaining a temperature of 500°C to 800°C at atmospheric pressure to obtain mesophase coke.

[0043] Furthermore, the method includes physically moving the container from the third heating zone to the cooling zone via the actuator unit, and discharging the mesophase coke from the outlet zone of the reactor.

[0044] In one embodiment of the invention, the method further includes feeding the isotropic bitumen from the reservoir into the container.

[0045] In another embodiment of the invention, the method includes cooling the mesophase coke in the cooling zone.

[0046] In one embodiment of the invention, the method further includes physically moving the container from the cooling zone to the outlet zone via a pusher unit.

[0047] In another embodiment of the invention, the method includes crushing the mesophase coke into coke particles within a crushing unit.

[0048] Furthermore, in another embodiment of the invention, the method includes using a pneumatic conveying system to transport the coke particles from the crushing unit to a hopper.

[0049] In another embodiment of the invention, the method further includes recovering and storing unused bitumen. The recovery step includes evaporating unused bitumen from the reactor, condensing the evaporated bitumen in a condensation unit to obtain condensed oil, and storing it in a storage tank.

[0050] These features, along with other objects of the invention and various novel features of the invention, are specifically pointed out in the appended claims and constitute a part of the invention. For a better understanding of the invention, its operational advantages, and the specific objectives achieved through its use, reference should be made to the appended description, in which exemplary embodiments of the invention are shown. Attached Figure Description

[0051] The advantages and features of the present invention will be better understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0052] Figure 1 This is an exemplary block diagram illustrating a system for producing mesophase coke from isotropic pitch according to various embodiments of the present invention.

[0053] Figure 2 This is an exemplary block diagram of a actuator unit according to various embodiments of the present invention.

[0054] Figure 3 A schematic flow diagram illustrating an exemplary method for producing mesophase coke from isotropic pitch according to various embodiments of the present invention.

[0055] Figure 4 The illustration shows optical micrographs of the appearance of mesophase coke according to various embodiments of the present invention.

[0056] Figure 5 The illustration shows graphs representing the charge capacity, discharge capacity, and first cycle efficiency of graphite by performing process parameters according to various embodiments of the present invention.

[0057] Figure 6 The illustration shows rounded-edge graphite particles according to various embodiments of the present invention.

[0058] Figure 7 A graph illustrating the size of graphite particles according to various embodiments of the present invention is shown.

[0059] In all the accompanying figures, the same numbers represent the same components. Detailed Implementation

[0060] For illustrative purposes, the exemplary embodiments described in detail herein have undergone numerous variations. However, it should be emphasized that the invention is not limited to the disclosed systems and methods for producing mesophase coke. It should be understood that various omissions and substitutions of equivalents may be contemplated where circumstances may suggest or be advantageous, but such omissions and substitutions are intended as alternative applications or implementations without departing from the spirit or scope of the invention.

[0061] Unless otherwise stated, the terms used in the specification and claims have the meanings commonly used in the field of coke production systems and the processes involved. Specifically, the following terms have the meanings as follows.

[0062] The terms “one” and “a” in this article do not indicate a limitation on quantity, but rather indicate the existence of at least one reference item.

[0063] The terms “having,” “containing,” “including,” and their variations in this article refer to the presence of a component.

[0064] The term "intermediate phase" in this article refers to an orthotropic liquid crystal structure that is readily graphitized and can serve as a promising raw material for preparing high-performance, multifunctional anisotropic graphite materials.

[0065] Figure 1 An exemplary block diagram illustrates a system (1000) for producing mesophase coke from isotropic pitch. The system (1000) includes a reservoir (200) containing the isotropic pitch. In one embodiment of the invention, the isotropic pitch is selected from at least one of coal tar or petroleum tar.

[0066] Furthermore, those skilled in the art will understand that the isotropic asphalt typically has a high aromatic content and a quinoline insoluble (QI) content of less than or equal to 2%. Additionally, the selected isotropic asphalt has a softening point (SP) temperature in the range of 80°C to 120°C. The isotropic asphalt used can be in liquid or solid form.

[0067] In the embodiments of the present invention, isotropic pitch having the above parameters, i.e., mesophase coke, will affect the type of the final product and its electrochemical performance.

[0068] In addition, such as Figure 1 As shown, the system (1000) includes a reactor (100) to produce the mesophase coke from the isotropic pitch.

[0069] The reactor (100) includes multiple zones (101), (102), (103), (104), (105), and (106). In one embodiment of the invention, the multiple zones include an inlet zone (101) having a container (50).

[0070] The container (50) is adapted to receive the isotropic bitumen from the storage container (200).

[0071] In the embodiment, the isotropic bitumen is pumped into the container (50) in a predetermined amount.

[0072] like Figure 1 As shown, the plurality of zones (101), (102), (103), (104), (105), and (106) also include a first heating zone (102) inside the reactor (100). The first heating zone (102) is adapted to pretreat the isotropic asphalt.

[0073] More specifically, in the embodiments of the present invention, the pretreatment of the isotropic asphalt is carried out at atmospheric pressure and at a temperature of 250°C to 350°C to reduce or eliminate many volatile emissions of the isotropic asphalt.

[0074] Furthermore, the plurality of regions (101), (102), (103), (104), (105), and (106) include a second heating zone (103) inside the reactor (100). The second heating zone (103) is adapted to heat the pretreated isotropic asphalt.

[0075] More specifically, the pretreated isotropic asphalt undergoes pyrolysis in the second heating zone (103) at atmospheric pressure and a temperature of 350°C to 500°C to convert the isotropic asphalt into mesophase asphalt.

[0076] In the embodiments of the present invention, within the stated temperature range, the physical appearance and chemical composition of the isotropic asphalt change. More specifically, the formation of an intermediate phase occurs in the isotropic asphalt. Subsequently, this may lead to the transformation of the isotropic asphalt into an anisotropic phase.

[0077] Furthermore, in the embodiments described, the mesophase pitch is presented as spheres, and the formation rate of the mesophase depends on the chemical composition of the precursor, i.e., the isotropic pitch.

[0078] More preferably, the formation of the mesophase depends on the residence time of the isotropic pitch in the reactor (100) and the temperature conditions for producing the mesophase coke.

[0079] Furthermore, more specifically, the stacked, flattened molecules of the asphalt form mesophase spheres. These mesophase spheres then expand and merge together to form blocky mesophase asphalt at the end of the second heating zone (103).

[0080] Furthermore, the plurality of heating zones (101), (102), (103), (104), (105), and (106) also include a third heating zone (104) inside the reactor (100). The third heating zone (104) is adapted to heat the mesophase pitch obtained at the end of the second heating zone (103).

[0081] More specifically, the pyrolysis of the mesophase pitch is carried out in the third heating zone (104) at a temperature of 500°C to 800°C for a predetermined time under atmospheric pressure. More preferably, the mesophase pitch is converted into mesophase coke in the third heating zone (104) at a temperature range of 500°C to 600°C.

[0082] The mesophase coke obtained after the third heating zone (104) is essentially anisotropic and has a mesophase content of 80% to 100%.

[0083] In another embodiment of the invention, the first heating zone (102), the second heating zone (103), and the third heating zone (104) further include a plurality of heating zones for finely controlling the temperature inside the heating zones (102), (103), and (104). More preferably, the plurality of heating zones operate at a temperature at which the mesophase coke will have high quality.

[0084] In one embodiment of the invention, the plurality of zones (101), (102), (103), (104), (105), and (106) further include a cooling zone (105). The cooling zone (105) is adapted to cool the mesophase coke obtained at the end of the third heating zone (104) (see [link to relevant documentation]). Figure 1 ).

[0085] Furthermore, the plurality of zones (101), (102), (103), (104), (105), and (106) include an outlet zone (106) inside the reactor (100). The outlet zone (106) is adapted to store the mesophase coke obtained from the cooling zone (106) (see [link to relevant documentation]). Figure 1 ).

[0086] In one embodiment of the invention, the system (1000) includes a actuator unit (300) (see [link]). Figure 1 and Figure 2 The pusher unit (300) is adapted to physically move the container from the inlet region (101) to the first heating region (102), the second heating region (103) and the third heating region (104), through the outlet region (106), to obtain mesophase coke in the outlet region (108).

[0087] In this embodiment, the actuator unit (300) includes a hydraulic actuator system. The hydraulic actuator system includes a hydraulic pump (302) to allow hydraulic fluid to flow from the base (301) through the fluid-hydraulic actuator system to generate hydraulic power. Further, the hydraulic actuator system includes a hydraulic valve (303) to regulate the flow rate of the hydraulic fluid to achieve a variable propulsion speed. This provides operational flexibility to vary the residence time in the plurality of zones (101), (102), (103), (104), (105), (106) to produce controlled mesophase materials (see [link]). Figure 2 ).

[0088] The hydraulic propulsion system also includes a hydraulic cylinder (304) for converting the hydraulic energy into mechanical energy to propel the container (50) through the plurality of zones (101), (102), (103), (104), (105), (106) (see See Figure 2 ).

[0089] In another embodiment of the invention, the system (1000) further includes a crushing unit (600). The crushing unit (600) is adapted to crush the mesophase coke discharged from the outlet zone (106) into coke particles (see...). Figure 1 Very small sizes must be sieved from the crushed coke, leaving an acceptable size of about 20 mm.

[0090] In another embodiment of the invention, the system (1000) further includes a pneumatic conveying system (700). The pneumatic conveying system (700) is adapted to convey the mesophase coke (see [link to original text]) from the mesophase coke. Figure 1The coke particles extracted from the coke are conveyed to a hopper (800) and stored in the hopper (800).

[0091] More preferably, the coke particles are conveyed into the hopper (800) through a closed pipe by using collective force pressure and air.

[0092] In the embodiment described, air pressure and flow are required to convey the coke particles from the crushing unit (600) to the hopper (800).

[0093] In another embodiment of the invention, the reactor (100) is also adapted to evaporate a portion of the asphalt.

[0094] In this embodiment of the invention, the system (1000) includes a condensation unit (400). The condensation unit (400) is adapted to condense the evaporated unused asphalt into condensed oil.

[0095] In another embodiment of the invention, the system (1000) may further include an oil tank (500). The oil tank (500) is adapted to store condensate containing the light cracking products.

[0096] The basic process for preparing mesophase coke related to system (1000) will now be explained with reference to the flowchart (see [link]). Figure 3 ).

[0097] In step (10), the method (900) includes feeding isotropic bitumen from a storage tank (200) into a container (50). The container (50) is then loaded into a reactor (100).

[0098] In one embodiment, the container (50) is placed in an inlet area (101) of the reactor (100) in a predetermined amount.

[0099] In step (12), the method (900) includes physically moving the container (50) filled with the isotropic asphalt to the first heating zone. The container (50) moves in a straight line at a fixed speed.

[0100] In an embodiment of the invention, the physical movement of the container (50) from the inlet area to the first heating zone (101) is accomplished by a pusher unit (300).

[0101] In step (14), the method (900) includes pretreating the isotropic asphalt within the first heating zone (102) of the reactor (100). The heating zone operates for a predetermined time at a temperature of 250°C to 350°C and atmospheric pressure (see [link to relevant documentation]). Figure 3 ).

[0102] In embodiments of the present invention, as described above, the isotropic asphalt needs to undergo the pretreatment or preconditioning to reduce or eliminate many of the volatile emissions from the isotropic asphalt.

[0103] Furthermore, in step (16), the method includes physically moving the container (50) from the first heating zone (102) to the second heating zone (103) via the actuator unit (300). Similarly, it should be understood that the material is not moved, but the container (50) moves within the reactor (100).

[0104] In an embodiment of the present invention, after the isotropic asphalt is pretreated, the container (50) filled with the pretreated asphalt is moved to the next section, namely the second heating zone (103).

[0105] In step (18), the method (900) includes heating the pretreated isotropic bitumen in the second heating zone (103) of the reactor (100) by maintaining a temperature of 350°C to 500°C at atmospheric pressure.

[0106] In this embodiment, changes in physical appearance and chemical composition occur within the stated temperature range. More specifically, in this embodiment, the formation of an intermediate phase occurs in the pretreated isotropic asphalt. Subsequently, this may lead to the transformation of the isotropic asphalt into anisotropic asphalt.

[0107] Furthermore, in the embodiments described, the mesophase pitch is presented as spheres, and the formation rate of the mesophase depends on the chemical composition of the precursor, i.e., the isotropic pitch.

[0108] Further in step (20), the method (900) includes physically moving the container (50) from the second heating zone (103) to the third heating zone (104) via the pushing unit (300).

[0109] In step (22), the method (900) continues by heating the mesophase pitch in the third heating zone (104) of the reactor (100) while maintaining the temperature at 450°C to 800°C. More preferably, mesophase coke is obtained at a temperature of 480°C to 600°C under atmospheric pressure (see...). Figure 3 Similarly, it should be understood that the material does not move, but rather the container (50) moves within the reactor (100).

[0110] In step (24), the method (900) includes physically moving the container (50) from the third heating zone (104) to the cooling zone (105) via the pusher unit (300).

[0111] In step (26), the method (900) further includes cooling the mesophase coke.

[0112] Furthermore, in step (28), the method (900) includes physically moving the container (50) from the cooling zone (105) to the outlet zone (106) via the pusher unit (300).

[0113] Furthermore, in step (30), method (900) includes discharging the mesophase coke from the outlet zone (106) (see...). Figure 3 ).

[0114] In step (32), the method (900) then involves crushing the mesophase coke within a crushing unit (600). The crushing is performed to convert the mesophase coke into coke particles.

[0115] Further in step (34), the method (900) includes conveying the coke particles from the crushing unit (600) to the hopper (800) via a pneumatic conveying system (700).

[0116] In another embodiment of the invention, unused bitumen is recovered. More preferably, during the production of mesophase coke within the reactor (100), a portion of the isotropic bitumen evaporates (see...). Figure 3 ).

[0117] In the above embodiments of the present invention, in step (36), the method (900) includes evaporating the unused asphalt from the reactor (100) to the condensation unit (400) (see...). Figure 3 ).

[0118] In step (38), the method (900) further includes condensing the evaporated asphalt in a condensation unit (400) to obtain condensed oil (see...). Figure 3 ).

[0119] Furthermore, in step (40), the method (900) includes pumping the condensate oil into the oil tank (500) (see...). Figure 3 ).

[0120] Compared to existing systems and methods, the systems and methods disclosed herein are feasible, sustainable, effective, and efficient. Furthermore, this invention ensures the homogeneity of the prepared mesophase coke.

[0121] In addition, traditional mesophase coke is generally made from mesophase pitch with a mesophase content of more than 50% and a softening point of more than 200°C. However, due to the high cost of mesophase pitch, there are very few products produced on an industrial scale.

[0122] Therefore, the present invention provides a system and method for producing mesophase coke from bitumen with a softening point below 200°C.

[0123] In existing batch processing, the precursor is pyrolyzed under high pressure until a certain amount of mesophase is produced. The mesophase pitch is then separated by mechanical or chemical processes, which require complex equipment and solvents.

[0124] Furthermore, the process of producing mesophase coke takes place in multiple heating zones within a single reactor, thus eliminating the need for high-temperature pumps and high pressure to transport the pitch. As with existing systems and processes, high-temperature pumps and high pressure are required to transfer the mesophase pitch from one reactor to another to complete the production of mesophase coke. To date, mesophase pitch has been produced in separate reactors / plants, and intermediate coke in another. In the disclosed system, it is a dome within a single reactor.

[0125] Furthermore, the residence time in this invention is very well controlled by the speed of the propeller unit. Therefore, it controls the formation of mesophase spheres during pyrolysis to prepare mesophase coke of reproducible quality. Moreover, the properties of the prepared mesophase coke are of particular significance in applications such as the production of graphite anodes for lithium-ion batteries.

[0126] Furthermore, to better understand the invention and demonstrate how the system and method can be implemented, various implementations will now be presented. Four experiments were conducted using the system and method with different parameters.

[0127] Example 1

[0128] The first embodiment illustrates the operation of the present invention using coal tar pitch with a softening point (SP) of 100 and a QI of 2%. The temperature of the first heating zone (102) was 250°C to 350°C, and the experiment was conducted at atmospheric pressure. The temperatures of the second heating zone (103) and the third heating zone (104) were set to 350°C to 500°C and 500°C to 800°C, respectively, with a residence time of 10 hours. The bulk mesophase coke obtained from the reactor (100) contained greater than 75% anisotropy. Optical micrographs of the appearance of the coke (see...) Figure 4 ).

[0129] The graphite anode prepared from the coke has a capacity of 335 mA / g and an initial cycle efficiency of 92%. The graphite anode is charged to 48% of its capacity at 2C and discharged at 99% at 3C.

[0130] Example 2

[0131] Example 2 illustrates the operation of the present invention in coal tar pitch with SP of 100 and QI < 0.2%. The temperature of the first heating zone (102) was 250°C to 350°C, and the experiment was conducted at atmospheric pressure. The temperatures of the second heating zone (103) and the third heating zone (104) were set to 350°C to 450°C and 450°C to 800°C, respectively, with a residence time of 10 hours. The bulk mesophase coke obtained from the reactor (100) contained more than 90% anisotropy.

[0132] The graphite anode prepared from the coke has a capacity of 355 mA / g and an initial cycle efficiency of 93%. The graphite anode is charged to 30% of its capacity at 2C and discharged at 92% at 3C. The charge-discharge profile of this graphite is shown below. Figure 5 As shown.

[0133] Example 3

[0134] This embodiment illustrates the operation of the invention, wherein the SP of the coal tar pitch is 100 and the QI is <0.2%. The temperature of zone 1 is 250°C to 350°C, and the experiment is conducted at atmospheric pressure. The temperatures of the second heating zone (103) and the third heating zone (104) are set to 350°C to 430°C and 450°C to 800°C, respectively, with a residence time of 20 hours. The bulk mesophase coke obtained from reactor (100) contains more than 90% anisotropy.

[0135] The graphite anode prepared from the coke has a capacity of 362 mA / g and an initial cycle efficiency of 93%. The graphite anode is charged to 30% of its capacity at 2C and discharged at 91% at a 3C rate.

[0136] Example 4

[0137] This embodiment illustrates the operation of the present invention using coal tar pitch with SP of 100 and QI < 0.2%. The temperature of the first heating zone (102) was 250°C to 350°C, and the experiment was conducted at atmospheric pressure. The temperatures of the second heating zone (103) and the third heating zone were set to 350°C to 450°C and 450°C to 550°C, respectively, with a residence time of 10 hours. The bulk mesophase coke obtained from the reactor (100) contained more than 90% anisotropy.

[0138] The graphite anode prepared from this coke has a capacity of 356 mA / g and an initial cycle efficiency of 94%. It is charged at 2C to 32% of its capacity and discharged at 3C at 93%. The density of this electrode can reach 1.8 g / cc.

[0139] Furthermore, the graphite particles produced by the above process have rounded edges (see...). Figure 6The rounded edges of the graphite particles ensure the electrode coating process. Therefore, the resulting high-density electrode can possess good porosity and particle orientation.

[0140] Furthermore, electrodes produced by the method can have better wettability and higher charge and discharge rates.

[0141] from Figure 7 The chart shown demonstrates that the size of the graphite particles can be controlled as needed. Furthermore, the chart is plotted between the percentiles of the graphite particles and their size.

[0142] Furthermore, the dimensions of the graphite particles are shown in Table 1 below:

[0143] Table 1

[0144]

[0145]

[0146] The raw materials and process parameters of the above embodiments are shown in Table 2 below:

[0147] Table 2

[0148]

[0149] Compared to the above embodiments, the performance of the battery in which the graphite anode is made of mesophase coke is shown in Table 3 below:

[0150] Table 3

[0151]

[0152]

[0153] The performance comparison data of the electrodes formed using the mesophase coke composition prepared by the method with those of the prior art are shown in Table 4 below.

[0154] Table 4

[0155]

[0156]

[0157] Therefore, this invention describes a method for achieving high-density electrodes. This will facilitate the manufacture of high-energy-density batteries. Furthermore, the produced electrodes exhibit better charge-discharge rates, making it possible to manufacture high-power batteries.

[0158] Therefore, the present invention is a system and method for producing coke that is feasible, sustainable, effective and efficient compared to existing methods.

[0159] The above description of specific embodiments of the invention is for illustrative purposes only. It is not intended to be exhaustive or to limit the invention to the precise forms disclosed, and it will be apparent that many modifications and variations can be made in accordance with the above teachings.

[0160] Furthermore, the embodiments were chosen and described in order to best explain the principles of the invention and its practical application, thereby enabling others skilled in the art to best utilize the invention and various embodiments with various modifications to suit a particular intended use. It should be understood that various omissions and substitutions of equivalents may be contemplated or become advantageous as circumstances may suggest, but such omissions and substitutions are intended to replace the application or implementation without departing from the spirit or scope of the invention.

[0161]

[0162]

Claims

1. A system (1000) for producing mesophase coke from isotropic pitch, characterized in that: The system includes: A reactor (100) includes: A storage container (200) is configured to store the isotropic bitumen and supply the isotropic bitumen to a container (50); An inlet area (101) having the container (50) for receiving the isotropic bitumen from the reservoir (200), and wherein the isotropic bitumen is contained in the container (50) during processing; A first heating zone (102) is adapted to pretreat the isotropic asphalt by operating the first heating zone at a temperature of 250°C to 350°C under atmospheric pressure; A second heating zone (103) is used to heat the pretreated isotropic asphalt by maintaining a temperature of 350°C to 500°C at atmospheric pressure to convert the isotropic asphalt into mesophase asphalt. A third heating zone (104) is used to heat the mesophase pitch by maintaining a temperature of 500°C to 800°C at atmospheric pressure to obtain mesophase coke; An outlet zone (106) is provided for discharging the mesophase coke from the reactor (100); and A controlled speed actuator unit (300) is used to physically move the container (50) from the inlet zone (101) sequentially through the first heating zone (102), the second heating zone (103), the third heating zone (104), and the outlet zone (106) to obtain mesophase coke in the outlet zone (106), wherein the controlled speed actuator unit (300) includes a hydraulic actuator system having a hydraulic valve (303) to regulate the flow rate of hydraulic fluid to achieve a variable driving speed.

2. The system as described in claim 1, characterized in that: The isotropic pitch is selected from at least one of coal tar or petroleum tar.

3. The system (1000) as described in claim 1, characterized in that: The isotropic asphalt has a softening point (SP) temperature of 80°C to 120°C and a quinoline insoluble (QI) content of less than or equal to 2%.

4. The system (1000) as described in claim 1, characterized in that: The reactor (100) further includes a cooling zone (105) adapted to cool the mesophase coke obtained from the third heating zone (104).

5. The system (1000) as described in claim 1, characterized in that: It further includes a crushing unit (600) for crushing the mesophase coke into coke particles.

6. The system (1000) as described in claim 5, characterized in that: It further includes a hopper (800) for receiving and storing the coke particles.

7. The system (1000) as described in claim 6, characterized in that: It further includes a pneumatic conveying system for conveying the coke particles from the crushing unit to the hopper (800).

8. The system (1000) as claimed in claim 1, characterized in that: It further includes a condensation unit (400) adapted to condense the asphalt evaporated from the system to obtain condensed oil.

9. The system (1000) as described in claim 8, characterized in that: It further includes an oil tank (500) suitable for storing the condensed oil.

10. A method (900) for producing mesophase coke from isotropic pitch using the system of claim 1, characterized in that: The method includes: The isotropic bitumen is fed into the container (50) placed in the inlet area (101) of the reactor (100); The container (50) is physically moved to the first heating zone (102) by the controlled speed actuator unit (300), wherein the container (50) moves in a straight line within the reactor (100); The isotropic asphalt is pretreated in the first heating zone (102) of the reactor (100), wherein the first heating zone (102) operates at a temperature of 250°C to 350°C under atmospheric pressure. The container (50) is physically moved from the first heating zone (102) to the second heating zone (103) by the controlled speed actuator unit (300); The pretreated isotropic asphalt is heated in the second heating zone (103) of the reactor (100) and kept at a temperature of 350°C to 500°C under atmospheric pressure to obtain mesophase asphalt; The container (50) is physically moved from the second heating zone (103) to the third heating zone (103) via the controlled speed actuator unit (300). The mesophase pitch is heated in the third heating zone (104) of the reactor (100) and maintained at a temperature of 500°C to 800°C under atmospheric pressure to obtain mesophase coke; The container (50) is physically moved from the third heating zone (104) to a cooling zone (105) via the controlled speed actuator unit (300); and The mesophase coke is discharged from the outlet zone (106) of the reactor (100).

11. The method (900) as claimed in claim 10, characterized in that: The isotropic pitch is selected from at least one of coal tar or petroleum tar, wherein the softening point (SP) temperature of the isotropic pitch is less than or equal to 100°C and the quinoline insoluble (QI) content is less than or equal to 2%.

12. The method (900) as described in claim 10, characterized in that: Further includes supplying the isotropic bitumen from the storage unit (200).

13. The method (900) as described in claim 10, characterized in that: This further includes cooling the mesophase coke in the cooling zone (105).

14. The method (900) as described in claim 10, characterized in that: Further, it includes physically moving the container (50) from the cooling zone (105) to the outlet zone (106) via the controlled speed actuator unit (300).

15. The method (900) as described in claim 10, characterized in that: The method further includes crushing the mesophase coke into coke particles within a crushing unit (600).

16. The method (900) as described in claim 15, characterized in that: The method further includes conveying the coke particles from the crushing unit (600) to a hopper (800) via a pneumatic conveying system (700).

17. The method (900) as claimed in claim 10, characterized in that: The method further includes recycling unused bitumen, the recycling steps of which include: Evaporation of unused bitumen from the reactor (100); and The evaporated asphalt is condensed in the condensation unit (400) to obtain condensed oil.

18. The method (900) as claimed in claim 17, characterized in that: The method further includes pumping the condensate oil into an oil tank (500).

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