System and method for producing mesophase coke from isotropic pitch

Abstract

The present invention provides a system (1000) for producing mesophase coke from isotropic pitch. The system includes a reactor having a first heating zone (102) for pretreating the isotropic pitch by operating at a temperature of 250°C to 350°C under ambient pressure. The reactor further includes a second heating zone (103) for heating the pretreated isotropic pitch by maintaining a temperature of 350°C to 500°C under ambient pressure to obtain mesophase pitch. The reactor includes a third heating zone (104) for heating the mesophase pitch by maintaining a temperature of 500°C to 800°C under ambient pressure to obtain mesophase coke. The system further includes a pusher unit (300) adapted to physically move the vessel (50) from the inlet zone (101) to the outlet zone (106) to obtain mesophase coke.

Description

[Technical field]

[0001] This application claims the benefit of complete application number 202021022401, filed May 28, 2020.

[0002] The present invention relates to a system and method for producing coke, more specifically, the present invention discloses a system and continuous method for producing mesophase pitch and mesophase coke from coal tar / petroleum tar pitch to be used as a feedstock for making carbon / graphite electrodes for secondary batteries. [Background technology]

[0003] The need for new materials is constantly being explored, and materials with very specific properties require specific manufacturing equipment and easy process control. Carbon materials have found an important niche in the field of new materials due to their many properties (mechanical strength and high modulus of elasticity, low density, high thermal and electrical conductivity, ion intercalation / absorption properties, etc.) that make them irreplaceable in some applications. One such application is Li-ion batteries, where pitch or coke is used as the carbon precursor to make the carbon / graphite anode.

[0004] However, pitch and coke should be anisotropic in nature and contain high mesophase content. Therefore, to overcome this problem, methods have come into existence for producing mesophase pitch. One such method is disclosed in US Patent No. 4,904,371.

[0005] The patent discloses an improved and simple process for producing a carbonaceous pitch product having a controlled mesophase content in the range of about 50-100%. The process involves heating a carbonaceous feed material that is substantially free of mesophase pitch at a temperature above 350° C. at ambient pressure for about six hours.

[0006] The method further includes subjecting the carbonaceous feed material to an additional heat soak in the absence of a sparging gas at a temperature range of 250° C. to 350° C. for up to 10 hours. Additionally, the method subsequently comprises heating the pretreated carbonaceous feed material in the presence of a non-oxidizing sparging gas at a temperature range of 350° C. to 500° C. for up to 10 hours, thereby forming a mesophase pitch.

[0007] However, it has been observed that the heat treatment time in the above method is up to 20 to 30 hours. Furthermore, inert gas is used for blanketing in the above disclosed method. Since inert gas is used only for blanketing, the above method consumes less gas by about 0.25 standard standard cubic feet per hour (SCFH) / pound, resulting in lower energy consumption.

[0008] Further, a similar process is disclosed in U.S. Patent No. 4,551,225, which discloses an improved process for preparing optically anisotropic pitch comprising heating a pitch feedstock at a temperature in the range of about 350° C.-450° C. while passing an inert gas through the pitch feedstock at a rate of at least 2.5 standard cubic feet per hour (SCFH) / pound, and then stirring the pitch feedstock at an agitator speed of about 500-600 rpm to obtain an essentially 100% mesophase pitch product suitable for carbon production.

[0009] However, the above process has been found to require high processing times and inert gas flow rates to produce anisotropic pitch. Furthermore, the process requires high RPM agitator equipment and the process only produces mesophase pitch.

[0010] Furthermore, another similar method for producing mesophase pitch is disclosed in US Patent No. 4,631,181. The method includes producing mesophase pitch by adding at least one of an alcohol and a phenol to heavy bitumen. Furthermore, the method includes pretreating the mixture at a temperature of at least 250° C. and then subjecting the pretreated mixture to a heat treatment.

[0011] However, it should be noted that the above methods require additives and high pressure to produce mesophase pitch, and furthermore do not result in a completely anisotropic pitch.

[0012] Another method for producing mesophase pitch is disclosed in U.S. Patent No. 4,704,333, which involves converting pitch to mesophase pitch in the presence of catalytically effective amounts of oxides, diketones, carboxylates and carbonyls of metals selected from vanadium, chromium, molybdenum, iron, nickel and cobalt.

[0013] Another method for producing mesophase pitch is disclosed in U.S. Patent No. 5,182,010. The method comprises the steps of: mixing about 0.1 to 20 moles of hydrogen fluoride (HF) and about 0.05 to 1.0 moles of boron trifluoride (BF) per mole of naphthalene derivative; 3 The method includes polymerizing a naphthalene derivative having at least one methyl group in the presence of a naphthalene derivative having at least one methyl group at a pressure of about 5 to 100 atmospheres and a temperature of about 180° C. to 400° C. for about 5 to 300 minutes.

[0014] However, it should be noted that the above method uses a catalyst, which may cause some of the metal catalyst to remain in the produced mesophase pitch, thereby impairing its purity. Moreover, the method requires a high-pressure vessel, which increases the capital investment and also increases the processing cost.

[0015] Another method for producing mesophase is disclosed in US Patent No. 4,512,874. The method involves subjecting petroleum pitch to a heat treatment at a temperature between 360° C. and 450° C. The method then transfers the heat treated pitch to a mesophase growth and coalescence step.

[0016] The method further includes growing and fusing only the mesophase by heating the transferred heat-treated pitch in the mesophase growth and fusing step and aging it at a temperature higher than 280° C. and lower than 350° C. The method finally includes removing the mesophase composed of the QI and QS components from the lower layer in the growth and fusing step.

[0017] However, the above method requires two tanks, one for forming the mesophase and the other for mesophase growth and fusion. Moreover, the isotropic material returns to the first tank after separation. Therefore, it becomes difficult to transport the highly viscous material from one tank to another.

[0018] Furthermore, US Patent No. 2,775,549 discloses a process for producing needle-like coke, which involves removing components from high boiling petroleum residua when heated at 350°C to 550°C, followed by coking the remaining residua in a still pool.

[0019] US Patent No. 9,777,221 also discloses a semi-continuous process for producing needle coke for low coefficient of thermal expansion (CTE) graphite electrodes. The process involves heating a needle coke precursor under pressure, thereby converting 60% to 90% of the coal tar distillate into green coke. The process subsequently calcines the green coke to produce the low coefficient of thermal expansion needle coke.

[0020] However, the above method requires approximately 2 kg / cm 2 ~7kg / cm 2 The system requires high pressures of 10 ...

[0021] Another such process is disclosed in U.S. Patent No. 4,219,405, which discloses the continuous production of coke. The process includes heating a preheated hydrocarbon and recycled condensate at a rate that increases the mesophase content of the mixture to between 30% and 60%. The process further includes heating the preheated mixture in a coking zone at a rate that forms green coke having a mesophase content of between 70% and 100%. The process then continuously removes the green coke from the coking zone and heats the removed coke in a calciner.

[0022] However, it should be noted that the feed pitch must have a mesophase content of 30-60% before entering the coking zone, requiring additional equipment to make the feed pitch.

[0023] Therefore, there is a need for a system and simple method for producing controlled mesophase coke that can eliminate high temperature pumps to transport viscous pitch and eliminate high pressure processes to reduce capital costs and ease of operation.

[0024] Additionally, there is a need for a system and method for producing mesophase coke that can eliminate the use of organic solvents, additives, or catalysts.

[0025] Additionally, there is a need for a system and method that can reduce processing time for producing mesophase coke.

[0026] In summary, there is a need for a system and method for producing mesophase coke that can overcome the above-mentioned drawbacks and provide a method that is easy to operate and cost-effective. Summary of the Invention

[0027] Accordingly, aspects of the present invention relate to a system and method for producing mesophase coke from isotropic pitch, both of which are cost-effective and overcome existing problems by providing high quality mesophase coke.

[0028] In one aspect of the invention, a system for producing mesophase coke from an isotropic pitch includes a reactor including an inlet zone having a vessel adapted to receive the isotropic pitch.

[0029] The reactor further comprises a first heating zone adapted to perform pretreatment of the isotropic pitch by operating the first heating zone at a temperature between 250° C. and 350° C. under ambient pressure. The reactor further comprises a second heating zone adapted to perform heating of the pretreated isotropic pitch by maintaining a temperature between 350° C. and 500° C. under ambient pressure to convert the isotropic pitch to obtain a mesophase pitch.

[0030] The reactor further comprises a third heating zone adapted to carry out heating of the mesophase pitch by maintaining a temperature between 500°C and 800°C under ambient pressure to obtain a mesophase coke. The reactor further comprises a cooling zone for cooling the product from a high temperature to a low temperature. The reactor further comprises an outlet zone adapted to discharge the mesophase coke from the reactor.

[0031] The system further includes a speed controlled pusher unit adapted to physically move the vessel at a controlled speed from the inlet zone to the first heating zone, the second heating zone, the third heating zone, to the outlet zone to obtain mesophase coke at the outlet zone, thereby eliminating the need to install an expensive pumping system to pump high temperature, highly viscous pitch from one reactor to another.

[0032] In one embodiment of the present invention, the isotropic pitch is selected from at least one of coal tar and petroleum tar, and has a softening point (SP) temperature in the range of 80°C to 120°C and a quinoline insoluble (QI) content of 2% or less.

[0033] In another embodiment of the invention, the system further includes a reservoir adapted to contain the isotropic pitch and to provide the isotropic pitch into the container.

[0034] In one embodiment of the invention, the reactor further comprises a cooling zone adapted to cool the mesophase coke obtained from the third heating zone.

[0035] In another embodiment of the invention, the system further comprises a grinding unit adapted to grind said mesophase coke into coke granules.

[0036] In one embodiment of the invention, the system further comprises a hopper adapted to store the coke granules.

[0037] The system further includes a pneumatic conveying system for transporting the coke granules from the grinding unit to the hopper.

[0038] The system further includes a vapor condensation unit and an oil storage unit adapted to condense the pitch vaporized from the system to obtain a condensed oil.

[0039] In an aspect of the invention, a method for producing mesophase coke from an isotropic pitch is disclosed. The method includes providing an isotropic pitch to a vessel located in an inlet zone of a reactor. The method then physically moves the vessel into a first heating zone via a pusher unit, the vessel moving in a linear motion within the reactor.

[0040] The method further includes physically moving the vessel from the first heating zone to a second heating zone via a pusher unit, and subsequently heating the pretreated isotropic pitch in the second heating zone of the reactor by maintaining a temperature between 350° C. and 500° C. under ambient pressure to obtain a mesophase pitch.

[0041] The method further includes physically moving the vessel from the second heating zone through the pusher unit to a third heating zone via a pusher unit, and subsequently heating the mesophase pitch in the third heating zone of the reactor by maintaining a temperature between 500° C. and 800° C. under ambient pressure to obtain mesophase coke.

[0042] The method further includes physically moving the vessel from the third heating zone through the pusher unit to a cooling zone and discharging the mesophase coke from an outlet zone of the reactor.

[0043] In one embodiment of the invention, the method further comprises providing the isotropic pitch from a reservoir into a container.

[0044] In another embodiment of the invention, the method includes cooling said mesophase coke in said cooling zone.

[0045] In one embodiment of the invention, the method further comprises physically moving the container from the cooling zone via a pusher unit to an exit zone.

[0046] In another embodiment of the invention, the method includes grinding the mesophase coke into coke granules in a grinding unit.

[0047] Additionally, in another embodiment of the present invention, the method includes transporting the coke granules from the grinding unit to a hopper using a pneumatic conveying system.

[0048] In another embodiment of the invention, the method further comprises recovering and storing virgin pitch, the recovering step including evaporating virgin pitch from the reactor and condensing the evaporated pitch in a condensation unit to obtain a condensed oil, which is stored in a storage tank.

[0049] This, together with the various features of novelty which characterize this disclosure, as well as other aspects of the invention, are particularly pointed out in the claims annexed hereto and forming a part hereof. For a better understanding of the present disclosure, its operating advantages, and certain objects attained by its uses, reference should be made to the accompanying descriptive matter in which illustrative embodiments of the invention are set forth.

[0050] The advantages and features of the present invention will be better understood by reference to the following detailed description taken in conjunction with the accompanying drawings. [Brief description of the drawings]

[0051] [Figure 1] FIG. 1 shows an exemplary block diagram illustrating a system for producing mesophase coke from isotropic pitch according to various embodiments of the present invention. [Diagram 2] 1 illustrates an exemplary block diagram of a pusher unit according to various embodiments of the present invention. [Diagram 3] 1 shows a flow chart illustrating an exemplary method for producing mesophase coke from isotropic pitch according to various embodiments of the present invention. [Figure 4] 1 shows optical micrographs of mesophase coke according to various embodiments of the present invention. [Diagram 5] 1 shows graphs depicting charge capacity, discharge capacity and first cycle efficiency of graphite by carrying out method parameters according to various embodiments of the present invention. [Figure 6] 1 illustrates graphite particles with rounded edges according to various embodiments of the present invention. [Figure 7] 1 shows a graph depicting the size of graphite particles according to various embodiments of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0052] Like numbers refer to like elements throughout the drawings.

[0053] The exemplary embodiments described in detail herein for purposes of illustration are subject to many variations. It should be emphasized, however, that the invention is not limited to the disclosed systems and methods for producing mesophase coke. Various omissions and substitutions of equivalents are contemplated where circumstances may suggest or represent expedient, but it is understood that these are intended to cover applications or practices that may be implemented without departing from the spirit or scope of the invention.

[0054] Unless otherwise specified, the terms used in this specification and claims have the meanings commonly used in the field of systems and methods for producing coke. Specifically, the following terms have the meanings set forth below:

[0055] The terms "a" and "an" as used herein do not denote a limitation of quantity, but rather denote the presence of at least one of the referenced item.

[0056] The terms "having," "comprising," and "including" and variations thereof denote the presence of elements.

[0057] The term "mesophase" herein refers to a nematic liquid crystal structure that is easily graphitizable and can be used as a promising feedstock for preparing high performance and multifunctional anisotropic graphitic materials.

[0058] 1 illustrates an exemplary block diagram of a system (1000) for producing mesophase coke from an isotropic pitch. The system (1000) includes a reservoir (200) for 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.

[0059] Moreover, those skilled in the art will appreciate that the isotropic pitch typically has a high aromatic content and a quinoline insoluble (QI) content of 2% or less. Furthermore, the selected isotropic pitch has a softening point (SP) temperature in the range of 80° C. to 120° C. The isotropic pitch used may be in a liquid or solid state.

[0060] In the above embodiment of the present invention, the isotropic pitch having the above parameters can affect the type of final product, the mesophase coke obtained, and its electrochemical properties.

[0061] Further, as shown in FIG. 1, the system (1000) includes a reactor (100) for carrying out the production of the mesophase coke from the isotropic pitch.

[0062] The reactor (100) comprises a number of zones (101), (102), (103), (104), (105), (106). In one embodiment of the invention, the number of zones comprises an inlet zone (101) having a vessel (50).

[0063] The container (50) is adapted to receive the isotropic pitch from the reservoir (200).

[0064] In the embodiment, the isotropic pitch is pumped into the vessel (50) in a predetermined amount.

[0065] As shown in Figure 1, the plurality of zones (101), (102), (103), (104), (105), (106) further comprises a first heating zone (102) within the reactor (100), the first heating zone (102) adapted to perform pre-treatment of the isotropic pitch.

[0066] More specifically, in the above embodiment of the invention, the isotropic pitch is preconditioned at ambient pressure at a temperature between 250° C. and 350° C. to reduce or eliminate much of the devolatilization of the isotropic pitch.

[0067] The plurality of zones (101), (102), (103), (104), (105), (106) further comprises a second heating zone (103) within the reactor (100), the second heating zone (103) adapted to effect heating of the pretreated isotropic pitch.

[0068] More specifically, pyrolysis of the pretreated isotropic pitch is carried out in the second heating zone (103) at ambient pressure and at a temperature between 350° C. and 500° C. to convert the isotropic pitch to mesophase pitch.

[0069] In the above embodiment of the invention, at the above temperature range, a change in the physical appearance and chemical composition of the isotropic pitch occurs. More specifically, the formation of mesophases occurs in the isotropic pitch. This may then result in the conversion of the isotropic pitch to an anisotropic phase.

[0070] Furthermore, in the above embodiment, the mesophase pitch appears as spheres, and the rate of formation of the mesophase depends on the chemical composition of the precursor, i.e., the isotropic pitch.

[0071] More preferably, the formation of the mesophase depends on the residence time of the isotropic pitch in the reactor (100) and the temperature conditions to produce the mesophase coke.

[0072] More specifically, the stacked flat molecules of the pitch form mesophase spheres which then expand and coalesce to form bulk mesophase pitch at the end of the second heating zone (103).

[0073] Moreover, the plurality of heating zones (101), (102), (103), (104), (105), (106) further comprises a third heating zone (104) within the reactor (100), the third heating zone (104) being adapted to carry out heating of the mesophase pitch obtained at the end of the second heating zone (103).

[0074] More specifically, the pyrolysis of the mesophase pitch is carried out in the third heating zone (104) at ambient pressure and at a temperature between 500°C and 800°C for a predetermined time. More preferably, the mesophase pitch is converted to mesophase coke in the third heating zone (104) at a temperature range between 500°C and 600°C.

[0075] The mesophase coke obtained after the third heating zone (104) is anisotropic in nature and has a mesophase content of 80% to 100% percent.

[0076] In another embodiment of the invention, the first heating zone (102), the second heating zone (103), and the third heating zone (104) further comprise multiple heating zones therein for precise control of temperatures within the heating zones (102), (103), (104). More preferably, the multiple heating zones operate at a temperature at which the mesophase coke is of high quality.

[0077] In one embodiment of the invention, the plurality of zones (101), (102), (103), (104), (105), (106) further comprises a cooling zone (105), said cooling zone (105) adapted to cool said mesophase coke obtained at the end of said third heating zone (104) (see FIG. 1 ).

[0078] The plurality of zones (101), (102), (103), (104), (105), (106) further comprises an outlet zone (106) within the reactor (100), adapted to store the mesophase coke obtained from the cooling zone (106) (see FIG. 1).

[0079] In one embodiment of the invention, the system (1000) includes a pusher unit (300) (see FIGS. 1 and 2 ) adapted to physically move the vessel from the inlet zone (101) to the first heating zone (102), the second heating zone (103), and the third heating zone (104) to the outlet zone (106) to obtain mesophase coke at the outlet zone (106).

[0080] In an embodiment, the pusher unit (300) includes a hydraulic pusher system including a hydraulic pump (302) to enable the flow of the hydraulic fluid from a base (301) through the hydraulic pusher system to generate hydraulic power. Additionally, the hydraulic pusher system includes a hydraulic valve (303) to regulate the flow of the hydraulic fluid to achieve variable pushing speeds, thereby providing operational flexibility to vary residence times in the multiple zones (101), (102), (103), (104), (105), (106) to produce controlled mesophase materials (see FIG. 2).

[0081] The hydraulic pusher system further includes a hydraulic cylinder (304) for converting the hydraulic energy into mechanical energy to push the container (50) through the plurality of zones (101), (102), (103), (104), (105), (106) (see FIG. 2).

[0082] In another embodiment of the invention, the system (1000) further comprises a crusher unit (600) adapted to crush the mesophase coke discharged from the outlet zone (106) into coke granules (see FIG. 1 ). The crushed coke must be screened for very small sizes, leaving an acceptable size of less than about 20 mm.

[0083] In another embodiment of the invention, the system (1000) further comprises a pneumatic conveying system (700) adapted to transport the coke granules extracted from the mesophase coke (see FIG. 1 ) to a hopper (800) where the granules are stored.

[0084] More preferably, the coke granules are transported to the hopper (800) through a sealed pipeline by using collective force pressure and air.

[0085] In the above embodiment, air pressure and flow is required to transport the coke granules from the crusher unit (600) to the hopper (800).

[0086] In another embodiment of the invention, the reactor (100) is further adapted to vaporize a portion of the pitch.

[0087] In this embodiment of the invention, the system (1000) includes a condensation unit (400) adapted to condense the vaporized virgin pitch into a condensed oil.

[0088] In another embodiment of the present invention, the system (1000) may further include an oil tank (500). The oil tank (500) is adapted to store condensed oil containing the light cracking products.

[0089] The underlying method for the preparation of mesophase coke as described with respect to the system (1000) will now be described with reference to a flow chart (see FIG. 3).

[0090] In step (10), the method (900) includes providing isotropic pitch from a reservoir (200) into a vessel (50). The vessel (50) is then loaded into a reactor (100).

[0091] In one embodiment, said vessel (50) is placed in an inlet zone (101) of the reactor (100) in a predetermined amount.

[0092] In step (12), the method (900) includes physically moving the container (50) filled with the isotropic pitch into a first heating zone (102), where the container (50) is moved at a constant speed in a linear motion.

[0093] In an embodiment of the invention, the physical movement of the container (50) from the inlet zone to the first heating zone (101) is performed via a pusher unit (300).

[0094] In step (14), the method (900) includes pretreating the isotropic pitch in the first heating zone (102) of the reactor (100), wherein the heating zone operates at ambient pressure and at a temperature between 250° C. and 350° C. for a period of time (see FIG. 3).

[0095] In an embodiment of the invention, the pre-treatment or pre-conditioning of the isotropic pitch, as explained above, is necessary to reduce or eliminate much of the volatile emissions of the isotropic pitch.

[0096] Further, in step (16), the method includes physically moving the vessel (50) from the first heating zone (102) to the second heating zone (103) via the pusher unit (300). Again, it should be understood that material is not moved, but rather the vessel (50) is moved within the reactor (100).

[0097] In an embodiment of the invention, after pre-treatment of the isotropic pitch, the vessel (50) filled with pre-treated pitch moves to the next section, the second heating zone (103).

[0098] In step (18), the process (900) includes heating the pretreated isotropic pitch in the second heating zone (103) of the reactor (100) by maintaining a temperature between 350°C and 500°C under ambient pressure.

[0099] In embodiments, changes in physical appearance and chemical composition occur in the temperature range. More specifically, in the embodiments, mesophase formation occurs in the pretreated isotropic pitch. This can then result in the conversion of the isotropic pitch to an anisotropic phase.

[0100] Furthermore, in the above embodiment, the mesophase pitch appears as spheres, and the rate of formation of the mesophase depends on the chemical composition of the precursor, i.e., the isotropic pitch.

[0101] 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 pusher unit (300).

[0102] In step (22), the process (900) continues by heating the mesophase pitch in the third heating zone (104) of the reactor (100) by maintaining a temperature between 450° C. and 800° C., more preferably between 480° C. and 600° C. (see FIG. 3) at ambient pressure to obtain mesophase coke. Again, it should be understood that the material is not moved, but rather the vessel (50) is moved within the reactor (100).

[0103] In step (24), the method (900) includes physically moving the container (50) from the third heating zone (104) via the pusher unit (300) to a cooling zone (105).

[0104] In step (26), the method (900) further includes cooling the mesophase coke.

[0105] Further, in step (28), the method (900) includes physically moving the container (50) from the cooling zone (105) to an exit zone (106) via a pusher unit (300).

[0106] Further in step (30), the method (900) includes discharging the mesophase coke from the outlet zone (106) (see FIG. 3).

[0107] In step (32), the process (900) continues with grinding the mesophase coke in a grinding unit (600), where grinding is necessary to convert the mesophase coke into coke granules.

[0108] Further, in step (34), the method (900) includes transporting the coke granules from the grinding unit (600) via a pneumatic conveying system (700) to a hopper (800).

[0109] In another embodiment of the invention, the recovery of virgin pitch is performed. More preferably, a portion of the isotropic pitch is vaporized during the production of mesophase coke in the reactor (100) (see FIG. 3).

[0110] In this embodiment of the invention, in step (36), the method (900) includes evaporating the virgin pitch from the reactor (100) to a condensation unit (400) (see FIG. 3).

[0111] In step (38), the process (900) further includes condensing the vaporized pitch in a condensation unit (400) to obtain a condensed oil (see FIG. 3).

[0112] Further, in step (40), the method (900) includes pumping the condensed oil into an oil tank (500) (see FIG. 3).

[0113] The system and method disclosed herein is feasible, sustainable, effective and efficient as compared to existing systems and methods. Furthermore, the present invention ensures the uniformity of the prepared mesophase coke.

[0114] Additionally, traditionally, mesophase coke has generally been made from mesophase pitch, which has a mesophase content greater than 50% and a softening point greater than 200°C, but this has rarely been done on an industrial scale due to the high cost of mesophase pitch.

[0115] Accordingly, the present invention provides a system and method for producing mesophase coke from a pitch having a softening point below 200°C.

[0116] In existing batch processes, the precursor is pyrolyzed at high pressure until a certain amount of mesophase is prepared. The mesophase pitch is then subjected to a separation process by mechanical or chemical methods, which requires complex equipment and solvents.

[0117] Furthermore, the present invention does not require high temperature pumps and high pressure to transport the pitch because the process for producing mesophase coke is done in multiple heated zones in a single reactor. Existing systems and methods require high temperature pumps and high pressure to transport the mesophase pitch from one reactor to another to complete the production of mesophase coke. In the past, it has been done to produce mesophase pitch in a separate reactor / plant and mesophase coke in a separate reactor / plant. In the present system, it is a dome in a single reactor.

[0118] Furthermore, the residence time in the present invention is very well controlled by the speed of the pusher unit. Thus, the formation of mesophase spheres during the pyrolysis process is controlled to prepare mesophase coke of reproducible quality. Furthermore, the properties of the prepared mesophase coke are of particular interest for applications such as the manufacture of graphite anodes for lithium-ion batteries.

[0119] Further, for a better understanding of the invention and to show how the system and method may be put into practice, various references are made herein. Using the system and method, four experiments were performed using different parameters. EXAMPLES

[0120] Example 1 The first example shows the operation of the present invention with a coal tar pitch having a softening point (SP) of 100 and a QI of 2%. The temperature of the first heating zone (102) was between 250°C and 350°C, and the experiment was carried out at ambient pressure. The temperatures of the second heating zone (103) and the third heating zone (104) were set at 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) has an anisotropy of more than 75%. External optical micrograph of the coke (see FIG. 4).

[0121] The graphite anode prepared from the coke gives 335 mAh / g with a first cycle efficiency of 92%. The graphite anode charges to 48% of its capacity at 2C and discharges to 99% at a 3C rate.

[0122] Example 2 This Example 2 illustrates the operation of the present invention with a coal tar pitch with SP of 100 and QI less than 0.2%. The temperature of the first heating zone (102) was between 250°C and 350°C and the experiment was carried out at ambient pressure. The temperatures of the second heating zone (103) and the third heating zone (104) were set between 350°C and 450°C and 450°C and 800°C, respectively, with a residence time of 10 hours. The bulk mesophase coke obtained from the reactor (100) has an anisotropy of more than 90%.

[0123] The graphite anode prepared from the coke gives 355 mAh / g with a first cycle efficiency of 93%. The graphite anode is charged to 30% of its capacity at 2C and discharged to 92% at a 3C rate. The charge / discharge curves of this graphite are shown in Figure 5.

[0124] Example 3 This example illustrates the operation of the present invention with a coal tar pitch with SP of 100 and QI of less than 0.2%. The temperature in zone 1 was between 250°C and 350°C and the experiment was carried out at ambient pressure. The temperatures in the second heating zone (103) and the third heating zone (104) were set at 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 the reactor (100) has an anisotropy of more than 90%.

[0125] The graphite anode prepared from the coke gives 362 mAh / g with a first cycle efficiency of 93%. The graphite anode charges to 30% of its capacity at 2C and discharges 91% at a 3C rate.

[0126] Example 4 This example illustrates the operation of the present invention with a coal tar pitch with SP of 100 and QI of less than 0.2%. The temperature of the first heating zone (102) was between 250°C and 350°C and the experiment was carried out at ambient pressure. The temperatures of the second heating zone (103) and the third heating zone (104) were set between 350°C and 450°C and 450°C and 550°C, respectively, with a residence time of 10 hours. The bulk mesophase coke obtained from the reactor (100) has an anisotropy of more than 90%.

[0127] A graphite anode prepared from the above coke gives 356mAh / g with a first cycle efficiency of 94%. It charges to 32% of its capacity at a 2C rate. It discharges to 93% at a 3C rate. This electrode can reach a density of up to 1.8g / cc.

[0128] Furthermore, the graphite particles produced by the above method have rounded edges (see FIG. 6). The rounded edge graphite particles facilitate the electrode coating process. Therefore, the resulting high density electrode can have good porosity and particle orientation.

[0129] Furthermore, the electrodes prepared by the above method may have better wettability and high charge / discharge rates.

[0130] From the graph shown in Figure 7, the size of the graphite particles can be controlled according to the requirement. Further, the graph is plotted between the percentile and size of the graphite particles.

[0131] Additionally, the graphite particle sizes are shown in Table 1 below. TIFF0007617952000001.tif86170

[0132] The feed materials and process parameters for the above examples are given in Table 2 below. TIFF0007617952000002.tif62170

[0133] For the above examples, the characteristics of the cells in which the graphite anode is made from mesophase coke are shown in Table 3 below. TIFF0007617952000003.tif56170

[0134] Comparative data on the performance of electrodes formed using mesophase coke compositions prepared according to the above methods versus the prior art are shown in Table 4 below. TIFF0007617952000004.tif44170

[0135] Therefore, the present invention describes a method that can achieve high density electrodes. This is therefore useful for making high energy density batteries. Furthermore, the electrodes made have better charge / discharge rates, which allows for making high power batteries.

[0136] Thus, the present invention is a system and method for producing coke that is feasible, sustainable, effective and efficient as compared to existing methods.

[0137] The foregoing descriptions of specific embodiments of the invention have been presented for purposes of illustration, and are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teaching.

[0138] Moreover, the embodiments have been chosen and described to best explain the principles of the invention and its practical application, thereby enabling those skilled in the art to best utilize the invention and various embodiments with various modifications suited to the particular uses contemplated. Various omissions and substitutions of equivalents have been contemplated where circumstances may suggest or render expedient, but it is understood that such omissions and substitutions are intended to be covered as may be applied or practiced without departing from the spirit or scope of the invention. TIFF0007617952000005.tif131170

Claims

1. 1. A system (1000) for producing mesophase coke from isotropic pitch, comprising: A reactor (100), comprising: an inlet zone (101) having a vessel (50), said vessel (50) adapted to receive said isotropic pitch; a first heating zone (102) adapted to carry out a pre-treatment of said isotropic pitch by operating said first heating zone (102) at a temperature between 250°C and 350°C under ambient pressure; a second heating zone (103) adapted to carry out heating of the pretreated isotropic pitch by maintaining a temperature of 350° C. to 500° C. under ambient pressure to convert the isotropic pitch into a mesophase pitch; a third heating zone (104) adapted to carry out heating of the mesophase pitch by maintaining a temperature of between 500° C. and 800° C. under ambient pressure to obtain a mesophase coke; and an outlet zone (106) adapted to discharge said mesophase coke from the reactor (100); A reactor (100) comprising: a pusher unit (300) adapted to physically move the vessel (50) from the inlet zone (101) through the first heating zone (102), through the second heating zone (103), through the third heating zone (104) to an outlet zone (106) to obtain mesophase coke in the outlet zone (106); A system (1000) for producing mesophase coke from isotropic pitch comprising:

2. 2. The system of claim 1, wherein the isotropic pitch is selected from at least one of coal tar or petroleum tar.

3. The system (1000) of claim 1, wherein the isotropic pitch has a softening point (SP) temperature in the range of 80° C. to 120° C. and a quinoline insoluble (QI) content of 2% or less.

4. storing the isotropic pitch; and The system (1000) of claim 1, further comprising a reservoir (200) adapted to provide the isotropic pitch into the vessel (50).

5. 2. The system (1000) of claim 1, wherein the reactor (100) further comprises a cooling zone (105) adapted to cool the mesophase coke obtained from the third heating zone (104).

6. 2. The system (1000) of claim 1, wherein the pusher unit (300) comprises a hydraulic pusher system having a hydraulic valve (303) for regulating hydraulic fluid flow to achieve variable pushing speeds.

7. The system (1000) of claim 1, further comprising a grinding unit (600) adapted to grind the mesophase coke into coke granules.

8. The system (1000) of claim 7, further comprising a hopper (800) adapted to receive and store the coke granules.

9. The system (1000) of claim 8, further comprising a pneumatic conveying system for transporting the coke granules from the grinding unit to the hopper (800).

10. 10. The system (1000) of claim 1, further comprising a condensation unit (400) adapted to condense the evaporated pitch from the system to obtain a condensed oil.

11. The system (1000) of claim 10, further comprising an oil tank (500) adapted to store the condensed oil.

12. 1. A method (900) for producing mesophase coke from isotropic pitch, comprising: Providing an isotropic pitch in a vessel (50) arranged in an inlet zone (101) of a reactor (100); physically moving the vessel (50) to a first heating zone (102) via a pusher unit (300), wherein the vessel (50) is moved in a linear motion within the reactor (100); pre-treating the isotropic pitch in the first heating zone (102) of the reactor (100), the first heating zone (102) operating at a temperature between 250°C and 350°C under ambient pressure; physically moving the container (50) from the first heating zone (102) to a second heating zone (103) via a pusher unit (300); heating the pretreated isotropic pitch in the second heating zone (103) of the reactor (100) by maintaining a temperature between 350°C and 500°C under ambient pressure to obtain a mesophase pitch; physically moving said container (50) from a second heating zone (103) through said pusher unit (300) to a third heating zone (103) via said pusher unit (300); heating the mesophase pitch in the third heating zone (104) of the reactor (100) by maintaining a temperature between 500°C and 800°C under ambient pressure to obtain a mesophase coke; physically moving the container (50) from the third heating zone (104) through the pusher unit (300) to a cooling zone (105); Discharging said mesophase coke from an outlet zone (106) of said reactor (100); A method comprising:

13. 13. The method (900) of claim 12, wherein the isotropic pitch is selected from at least one of coal tar or petroleum tar, and the isotropic pitch has a softening point (SP) temperature of 100° C. or less and a quinoline insoluble (QI) content of 2% or less.

14. The method (900) of claim 12, comprising providing the isotropic pitch from a reservoir (200).

15. 13. The method (900) of claim 12, comprising cooling the mesophase coke in the cooling zone (105).

16. 20. The method (900) of claim 15, comprising physically moving the container (50) from the cooling zone (105) via a pusher unit (300) to an exit zone (106).

17. 13. The method (900) of claim 12, comprising grinding the mesophase coke into coke granules in a grinding unit (600).

18. 20. The method (900) of claim 17, comprising transporting the coke granules from the grinding unit (600) via a pneumatic conveying system (700) to a hopper (800).

19. and recovering the virgin pitch, said recovering step comprising: evaporating virgin pitch from said reactor (100); condensing the evaporated pitch in a condensation unit (400) to obtain a condensed oil; 13. The method of claim 12, comprising:

20. 20. The method (900) of claim 19, comprising pumping the condensed oil to an oil tank (500).

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