Graphitization furnace including channels with plate-shaped wall segments

Abstract

This disclosure relates to a graphitization furnace 100 configured for graphitizing particulate carbonaceous material. The graphitization furnace 100 includes a raw material inlet 160 and a product outlet 170, and a channel 110 connecting the raw material inlet 160 and the product outlet 170. The channel 110 includes an upstream section 120 closer to the raw material inlet 160 and a downstream section 130 closer to the product outlet 170. Both the upstream section 120 and the downstream section 130 include a plurality of discrete plate-shaped wall segments 140, 150, and both the upstream section 120 and the downstream section 130 have a polygonal cross-sectional shape.

Description

Technical Field

[0001] The present invention relates to the field of graphitization furnaces. More specifically, the present invention relates to a graphitization furnace including a channel containing plate-shaped wall segments.

Background Art

[0002] The most commonly commercially used anode material in lithium-ion batteries is graphite. Graphite can be lithiated to the state of LiC6, which correlates to a theoretical maximum capacity of 372 mAh / g.

[0003] Artificial graphite can be produced by heating a carbonaceous starting material (e.g., coke and / or pitch, etc.) to a temperature of about 3000 °C under the exclusion of oxygen. The heating can be carried out in a batch furnace or a continuous furnace. In a continuous furnace, the carbonaceous material is typically conveyed along a heated channel and transforms into graphite while being conveyed.

[0004] The continuous graphitization process can be advantageous. The reason is that it can produce graphite more efficiently than a batch process and can enable production on an industrial scale. However, the inventors have found that some carbonaceous materials (especially carbonaceous materials in powder form) may tend to cake in a continuous furnace. Caking can lead to a non-uniform temperature distribution, and it can result in a reduction in product quality and consistency. Also, it can result in a reduction in process efficiency and higher production costs due to interruptions in the continuous process while eliminating channel blockages induced by caking and the need to reprocess some products that were not fully graphitized due to caking.

[0005] To address the above problems, the inventors have developed a graphitization furnace. [Overview of the Initiative] [Means for solving the problem]

[0006] This disclosure relates to a graphitization furnace configured to graphitize particulate carbonaceous material. The graphitization furnace includes a raw material inlet and a product outlet, and a channel connecting the raw material inlet and the product outlet. The channel includes an upstream section closer to the raw material inlet and a downstream section closer to the product outlet. Both the upstream and downstream sections include a plurality of discrete plate-shaped wall segments, and both the upstream and downstream sections have a polygonal cross-sectional shape.

[0007] In some embodiments, the channel may include a central channel axis, and the upstream and downstream sections may be arranged along the central channel axis.

[0008] In some embodiments, the cross-sectional shape of the upstream section and / or downstream section can be a polygon having n corners, where n is an integer between 3 and 12.

[0009] In some embodiments, the cross-sectional shape can be formed by a plurality of discrete plate-shaped wall segments.

[0010] In some embodiments, the graphitization furnace can be configured such that the material flow within the graphitization furnace is gravity-assisted.

[0011] In some embodiments, the graphitization furnace can be a vertical (upright) type graphitization furnace.

[0012] In some embodiments, the graphitization furnace may include an isolation structure surrounding the channel.

[0013] In some embodiments, at least two adjacent discrete plate-shaped wall segments among a plurality of discrete plate-shaped wall segments can be connected by at least one joint, in particular, at least one removable joint.

[0014] In some embodiments, at least one joint may include a dowel joint, a miter joint, a cross-dowel joint, or a dovetail joint.

[0015] In some embodiments, at least one joint may include a screw, more specifically a carbonaceous screw, and in particular a screw made of graphite or carbon fiber reinforced carbon (CFRC).

[0016] In some embodiments, at least one joint may include a clamp.

[0017] In some embodiments, multiple plate-shaped wall segments can be joined together by wrapping or clamping, in particular by wrapping with graphite fibers and / or carbon fibers.

[0018] In some embodiments, at least one joint can be sealed.

[0019] In some embodiments, the joint is sealed by sealing means including pitch, resin, carbon, graphite, graphite mat, graphite foil, expanded graphite, carbon mat, carbon felt and / or graphite felt, carbon fiber, CFRC.

[0020] In some embodiments, at least one discrete plate-shaped wall segment can include a high-temperature heat-resistant hard coating, and in particular, all discrete plate-shaped wall segments of the downstream section can include a high-temperature heat-resistant hard coating.

[0021] In some embodiments, at least one wall segment of a plurality of discrete plate-shaped wall segments can be gas-permeable.

[0022] In some embodiments, the first discrete plate-shaped wall segment of the depicted channel can be gas-permeable, and the second discrete plate-shaped wall segment can be gas-impermeable.

[0023] In some embodiments, the graphitization furnace can include a gas outlet.

[0024] In some embodiments, the gas outlet can be a tube extending through an isolation structure.

[0025] In some embodiments, the channel can include a heating zone, a high-temperature reaction zone, and a cooling zone.

[0026] In some embodiments, the heating zone can be disposed adjacent to the raw material inlet, the cooling zone can be disposed adjacent to the product outlet, and / or the high-temperature reaction zone can be disposed between the heating zone and the cooling zone.

[0027] In some embodiments, the gas outlet can be disposed in the heating zone and / or the high-temperature reaction zone.

[0028] In some embodiments, at least one gas-permeable discrete plate-shaped wall segment can be arranged in the heating zone and / or high-temperature reaction zone.

[0029] In some embodiments, the channel may include at least one gas inlet in the cooling zone or the high-temperature reaction zone.

[0030] In some embodiments, at least one gas-impermeable discrete plate-shaped wall segment can be arranged in the cooling zone, and in particular, all discrete plate-shaped wall segments arranged in the cooling zone can be gas-impermeable.

[0031] In some embodiments, at least one gas inlet can be connected to a gas pump and / or pressure regulator, the purge gas pump and / or pressure regulator being configured, among other things, to maintain a pressure above ambient pressure inside the graphitization furnace.

[0032] In some embodiments, at least one gas inlet can be connected to a heat exchanger configured to preheat the injected gas.

[0033] In some embodiments, at least one of the multiple discrete plate-shaped wall segments may contain graphite or is composed of graphite, and in particular, all of the multiple discrete plate-shaped wall segments may contain graphite or is composed of graphite.

[0034] In some embodiments, at least one discrete plate-shaped wall segment can be a heating element or an electrode.

[0035] In some embodiments, the wall thickness of the channel can be between approximately 5 mm and approximately 200 mm, and in particular, the wall thickness of multiple discrete plate-shaped wall segments can be between approximately 5 mm and approximately 200 mm.

[0036] In some embodiments, the channel may include a stirrer comprising a shaft and at least one mixing paddle.

[0037] In some embodiments, at least one mixing paddle can be positioned in the cooling zone.

[0038] In some embodiments, the wall thickness of at least one discrete plate-shaped wall segment in the cooling zone can be greater than the wall thickness of at least one discrete plate-shaped wall segment in the heating zone, more specifically, the wall thickness of at least one discrete plate-shaped wall segment in the cooling zone can be between approximately 10% and approximately 200% greater than the wall thickness of at least one discrete plate-shaped wall segment in the heating zone.

[0039] In some embodiments, the wall thickness of at least one discrete plate-shaped wall segment in the high-temperature reaction zone can be greater than the wall thickness of at least one discrete plate-shaped wall segment in the heating zone, more specifically, the wall thickness of at least one discrete plate-shaped wall segment in the high-temperature reaction zone can be between approximately 10% and approximately 200% greater than the wall thickness of at least one discrete plate-shaped wall segment in the heating zone.

[0040] In a second embodiment, the disclosure relates to a method of using a graphitization furnace according to any prior embodiment to prepare graphite from carbonaceous raw materials. [Brief explanation of the drawing]

[0041] [Figure 1] This figure shows an exemplary schematic cross-section of a graphitization furnace according to the first embodiment. [Figure 2] This is an illustrative schematic isometric view of a channel containing multiple plate-shaped wall segments. [Modes for carrying out the invention]

[0042] The following provides a detailed description of this disclosure. Terms or phrases used in the description and embodiments of this disclosure are not to be constrained to have only common language or dictionary meanings, but rather to have their ordinary technical meanings as established in the relevant art, unless specifically defined otherwise in the following description. The detailed description will refer to specific embodiments to better illustrate this disclosure, but it is understood that the disclosure presented is not limited to these specific embodiments.

[0043] This disclosure relates to a graphitization furnace 100 configured for graphitizing particulate carbonaceous material. The graphitization furnace 100 includes a raw material inlet 160 and a product outlet 170, and a channel 110 connecting the raw material inlet 160 and the product outlet 170. The channel 110 includes an upstream section 120 closer to the raw material inlet 160 and a downstream section 130 closer to the product outlet 170. Both the upstream section 120 and the downstream section 130 include a plurality of discrete plate-shaped wall segments 140, 150, and both the upstream section 120 and the downstream section 130 have a polygonal cross-sectional shape.

[0044] The inventors have found that by dividing the furnace (or, more specifically, its channel in contact with the carbonaceous material) into multiple plate-shaped segments along the flow direction of the carbonaceous material, the construction, maintenance, and repair of the graphitization furnace can be carried out in a highly simplified and cost-effective manner. Both the use of plate-shaped wall segments and their arrangement in a continuous sequence (i.e., upstream and downstream) have been found to be extremely useful features for achieving cost-effective operation of the graphitization furnace. The feasible benefits will be illustrated below with the help of (non-limiting) examples.

[0045] The heat treatment of carbonaceous starting materials can be carried out in a continuous furnace (i.e., a furnace configured for the continuous or semi-continuous production of graphite). Typically, the carbonaceous raw material is transported along a channel between the raw material inlet and the product outlet while being heated. The movement of the carbonaceous material through the furnace can lead to wear on the channel walls. However, the rate of wear can vary significantly along the channel. For example, in a vertical graphitization furnace, a material column forms in the channel between the raw material inlet and the product outlet, resulting in increased pressure in furnace sections located closer to the product outlet. As a result, the rate of wear can increase in parts of the channel located closer to the product outlet. Furthermore, stirrers can be used to prevent caking and / or agglomeration of the carbonaceous material in some (but not all) sections of the furnace. This, again, can result in an increased rate of wear in those furnace sections housing the stirrers. Also, hotter sections of the furnace may experience more wear than cooler sections of the furnace. Segmenting the channel 110 in the upstream section 120 and downstream section 130, which each contain multiple discrete plate-shaped wall segments 140 and 150, respectively, allows for the positioning of individual segments to be adjusted to areas of higher wear (e.g., the downstream area) and enables the individual replacement of worn wall segments.

[0046] Furthermore, the production and maintenance costs of the furnace can be kept low by relying on plate-shaped wall segments. While curved or even more complex shapes can (and are indeed) be easily cut from large blocks of graphite, plate-shaped wall segments have the advantage of being easier to mill from graphite blocks with only minimal cutoffs. Since graphite is an expensive material due to its resource-intensive production, avoiding cutoffs is a significant cost-saving factor. Moreover, arranging discrete plate-shaped wall segments 140, 150 in polygonal cross-sectional shapes in both the upstream section 120 and the downstream section 130 may help to use identical plate-shaped wall segments to construct the channels, potentially reducing the overall number of parts / part shapes used to construct the furnace. This may be even more beneficial in that the number of parts to be stored for potential furnace maintenance may be reduced.

[0047] The present invention will now be described in more detail.

[0048] This disclosure relates to the production of graphite. The term "graphite" is well known and has a common meaning in the art. More specifically, the term "graphite" can refer to a material containing crystalline carbon with a hexagonal structure. Alternatively or additionally, the term "graphite" can refer to a material having a degree of graphitization of at least about 46%, more specifically 69%, even more specifically at least about 80%, and in particular at least about 83%.

[0049] Here and elsewhere, the term “wall section” refers to a portion of the wall of a channel, more specifically, a portion of the wall having a length of at least 5 cm, and more specifically, at least 10 cm. In particular, the term “wall section” can refer to a portion of the wall having a length of at least 5 cm, in particular, at least 10 cm, and a width of at least 10 cm. For example, a wall section could be one side of the downstream section 130, for example, one discrete plate-shaped wall segment 140, 150.

[0050] The term “particulate material” is well known and has a common meaning, particularly in the art. Additionally or alternatively, the term “particulate material” can refer to discrete particles having a size (e.g., diameter) of at least 1 μm. Additionally or alternatively, the term “particulate material” can refer to discrete (optionally, granular) particles having an average size of at least about 5 μm and up to about 20 cm.

[0051] The term "carbonaceous material" is well known and has a common meaning, particularly in the art. Additionally or alternatively, the term "carbonaceous material" can refer to a material containing carbon. More specifically, the term "carbonaceous material" can refer to a material containing at least 20% by weight, more specifically, at least 40% by weight, and in particular, at least 60% by weight, of the total weight of the material.

[0052] The term “discrete plate-shaped wall segment” is well known and has a common meaning, particularly in the art. Additionally or alternatively, the term “discrete plate-shaped wall segment” can refer to a wall segment constituting a separate entity. Additionally or alternatively, the term “discrete plate-shaped wall segment” can refer to a wall segment that can be separated from another wall segment without destroying any of the wall segments. Additionally or alternatively, the term “discrete plate-shaped wall segment” can refer to a wall segment composed of a continuous material, in particular, a “discrete plate-shaped wall segment” being separated from another “discrete plate-shaped wall segment” by a discontinuity in the material. The discontinuity in the material can be, for example, a gap, a sealing means, or a joint. Additionally or alternatively, the term “discrete plate-shaped wall segment” can refer to a wall segment that is singular. Additionally or alternatively, the term “discrete plate-shaped wall segment” can refer to a wall segment that is monoblock.

[0053] Figure 1 shows an exemplary schematic cross-section of a graphitization furnace 100 according to a first embodiment. The graphitization furnace 100 includes a raw material inlet 160 and a product outlet 170, and a channel 110 connecting the raw material inlet 160 and the product outlet 170. Carbonaceous material is fed into the channel 110 via the raw material inlet 160 and converted to graphite as it passes through the channel 110. The graphite is then discharged through the product outlet 170. In some embodiments, the raw material inlet 160 can be connected to a hopper containing carbonaceous raw materials. In some embodiments, the product outlet 170 can be connected to a collection tank or a cooling device. Furthermore, the channel 110 includes an upstream section 120 closer to the raw material inlet 160 and a downstream section 130 closer to the product outlet 170. The channel 110 can include a central channel axis 200. The orientation of the central channel axis 200 can correspond to the material flow direction F. In some embodiments, the upstream section 120 and the downstream section 130 can be arranged along the central channel axis 200. Both the upstream section 120 and the downstream section 130 include a plurality of discrete plate-shaped wall segments 140, 150, and both the upstream section 120 and the downstream section 130 have a polygonal cross-sectional shape. It should be noted that the graphitization furnace 100 can have a plurality of channel sections 110 and is not limited to one downstream section 130 and one upstream section 120.

[0054] Figure 2 shows an exemplary schematic isometric view of a channel 110 containing multiple discrete plate-shaped wall segments 140, 150. The channel 110 has a rectangular cross-section. The upstream section 120 contains four discrete plate-shaped wall segments 140, two of which, 140a and 140b, can be seen in Figure 2. The downstream section 130 contains four discrete plate-shaped wall segments 150, two of which, 150a and 150b, can be seen.

[0055] In some embodiments, the graphitization furnace 100 can be configured so that the material flow within the graphitization furnace 100 is gravity-assisted. While the material flow can be gravity-assisted, the graphitization furnace 100 (in particular, the channel 110) can additionally include conveying means to control, for example, the rate of material flow and / or discharge from the product outlet 170. In some embodiments, the graphitization furnace 100 can be a vertical graphitization furnace 100. As described above, in a vertical graphitization furnace, the rate of wear may vary along the channel length, which may require the replacement of discrete plate-shaped wall segments 140, 150 at different points in time.

[0056] The following section discusses measures for joining the discrete plate-shaped wall segments 140 and 150.

[0057] In some embodiments, at least two adjacent discrete plate-shaped wall segments 140, 150 of a plurality of discrete plate-shaped wall segments 140, 150 can be connected by at least one joint (in particular, at least one removable joint). The at least one removable joint can allow the discrete plate-shaped wall segments 140, 150 to be removed from and replaced from the channel 110. As described above, the discrete plate-shaped wall segments 140, 150 may be subject to significant wear, for example, due to the movement of carbonaceous material within the channel 110. In particular, the wear rate may be higher in the downstream section 130 due to increased pressure. When a discrete plate-shaped wall segment is worn, it can be replaced by removing the discrete plate-shaped wall segment when using a removable joint. Furthermore, at least one removable joint, combined with multiple discrete plate-shaped wall segments, can enable improved maintenance of other components (in particular, the channel 110) located within the graphitization furnace 100. As stated, the graphitization furnace 100 may include additional parts such as a stirrer. The stirrer or its parts (e.g., a mixing paddle) may also wear out during the operation of the furnace. Replacement or repair of the stirrer or its parts can be facilitated by removing at least one plate-shaped wall segment 140, 150 from the channel 110 by opening at least one joint.

[0058] Additionally or alternatively, in some embodiments, at least one discrete plate-shaped wall segment may include a high-temperature resistant hard coating. For example, tantalum carbide and tantalum hafnium carbide are hard ceramics exhibiting melting points above 3800°C. However, given the temperature and the fact that some contaminants present in the graphite (e.g., halides or sulfur) may attack the hard coating, the discrete plate-shaped wall segments 140, 150 may require recoating after some time, which can be facilitated using at least one removable joint. In some embodiments, the discrete plate-shaped wall segments 150 forming the downstream section 130 may include a high-temperature resistant hard coating. As stated above, the rate of wear may be highest in the downstream section 130 due to the increased pressure. Additionally, all discrete plate-shaped wall segments 140, 150 forming the channel 110 may include a high-temperature resistant hard coating.

[0059] In some embodiments, at least one joint may include a dowel joint, a miter joint, a cross-dowel joint, or a dovetail joint.

[0060] In some embodiments, at least one joint may include a screw, more specifically a carbonaceous screw or bolt, in particular a screw or bolt containing graphite or carbon fiber reinforced carbon (CFRC). For example, a miter joint may be held together by a carbonaceous screw, which may be removed to allow separation of at least two adjacent discrete plate-shaped wall segments 140, 150. The threads for the screw may be disposed on one of the at least one discrete plate-shaped wall segments 140, 150 being connected. The bolt may be used with a nut, more specifically with a carbonaceous nut containing or composed of graphite and / or CFRC.

[0061] In some embodiments, the screw or bolt may contain at least about 90 wt% CFRC or graphite, and in particular at least about 99 wt% CFRC or graphite, relative to the total weight of the carbonaceous screw. The term "CFRC" is well known and has its common meaning in the art. More specifically, the term "CFRC" may refer to a composite material containing carbon fibers in a graphite matrix. In particular, the term "CFRC" may refer to a composite material consisting of carbon fibers in a graphite matrix.

[0062] In some embodiments, at least one joint may include a clamp. The clamp may also contain graphite or be composed of graphite. In some embodiments, multiple discrete plate-shaped wall segments 140, 150 may be joined by wrapping, in particular by wrapping with graphite fibers and / or carbon fibers. Clamps or wrapping can press multiple discrete plate-shaped wall segments 140, 150 together and join them. Clamps or wrapping can be used in addition to other types of joints (e.g., box joints or dovetail joints). Clamping and / or wrapping can be used, in particular, to connect discrete plate-shaped wall segments 140, 150 at the same level. For example, clamping and / or wrapping can be used to join all discrete plate-shaped wall segments 140, 150 in a downstream section 130, while, on the other hand, dovetail joints can be used to join the downstream section 130 to the upstream section 120.

[0063] In some embodiments, at least one joint can be sealed. For example, a joint can be sealed to prevent particulate carbonaceous material from escaping from the channel 110. Furthermore, the sealing can assist in guiding the flow of inert gas and / or purge gas in the channel 110. In some embodiments, at least one joint can be sealed by a sealing means. In some embodiments, the sealing means can include pitch or resin. The pitch can be graphitized during use of the graphitization furnace 100. Additionally or alternatively, in some embodiments, the sealing means can include graphite mat, graphite foil, expanded graphite or carbon mat, for example, a carbon fiber mat. In some embodiments, the joint can include carbon fiber and / or CFRC. The mat can be bonded to discrete plate-shaped wall segments 140, 150 using pitch. Additionally or alternatively, in some embodiments, the sealing means can include carbon felt or graphite felt. Additionally, carbon mats, carbon fibers, or carbon felt may graphitize during use of the graphitization furnace 100.

[0064] In some embodiments, the cross-sectional shape of the upstream section 120 and / or downstream section 130 can be a polygon having n corners, where n is an integer between 3 and 12. More specifically, the cross-sectional shape can be triangular, rectangular, square, or hexahedron, and in particular can be rectangular. The cross-sectional shape can be the inner circumference of the cross-section of the channel 110 section perpendicular to the central channel axis 200. In some embodiments, the cross-sectional shape can be formed by a plurality of discrete plate-shaped wall segments 140, 150. Square or rectangular cross-sectional shapes can allow for facilitated construction, for example, because joints can be formed where two discrete plate-shaped wall segments 140, 150 abut orthogonally. Rectangular shapes may be advantageous (compared to square shapes in particular) in that the distance that volatile impurities (ash) released during graphitization must travel to reach the nearest wall is reduced. On the other hand, hexagonal cross-sections can provide a low surface-to-volume ratio and high stability. Since heat transfer is generally proportional to the surface area of ​​an object, a furnace exhibiting a lower surface-to-volume ratio can lead to higher thermal efficiency. And higher thermal efficiency can result in higher energy efficiency for the high-temperature process of graphitization. Furthermore, the graphitization furnace 100 can include additional structures. In some embodiments, the (vertical) graphitization furnace 100 can include an isolation structure surrounding the channel 110. The isolation structure surrounding the channel 110 is not depicted for overview purposes. Because the isolation structure surrounds the channel 110, the combined surface-to-volume ratio of the isolation structure and the channel 110 will also be smaller with respect to a hexagon compared to a triangular or rectangular cross-sectional shape, which is typical.

[0065] The following section discusses measures for removing gas from channel 110.

[0066] Additionally, constructing the channel 110 using discrete plate-shaped wall segments 140, 150 allows for variations in the material properties of the channel 110 in different sections of the channel 110. As described above, during graphitization, volatile impurities can be released as gases from the carbonaceous material. These impurities (also referred to as ash) can be released as gases from the carbonaceous material during graphitization. For example, coke (which can be used as a carbonaceous starting material) can contain up to 20% by weight of ash. In order to obtain high-quality graphite from the graphitization process, the ash needs to be removed from the carbonaceous material and, consequently, from the channel 110. As a result, at least a portion of the channel 110 must allow gas to escape, while other sections can preferably be gas-impermeable to control the direction of gas flow. This allows, for example, the ash to be removed in a directed manner through a section of the channel 110 that allows the gas to escape when pressure is applied to the channel 110 by feeding a purge gas into the channel 110.

[0067] The channel can be surrounded, for example, by the aforementioned isolation structure that surrounds the channel, which does not have to be gas permeable. However, a gas removal system or outlet can be located through the isolation structure. Therefore, for efficient ash removal, it may be advantageous to make a section of channel 110 near the gas removal system or outlet gas permeable.

[0068] In these and other instances, references to gas-permeable structures or materials include, among other things, at least 0.3 cm as measured according to DIN 51935:2019-07. 2 This may refer to a structure or material having a gas permeability of 0.3 cm² / s. In these and other instances, references to gas-impermeable structures or materials are, among other things, measured according to DIN 51935:2019-07.2 It is possible to refer to a structure or material having a gas permeability lower than / s. Suitable structures or materials with the required gas (impermeability) are well known to those skilled in the art. For example, Sigrafine HLR, HLM, and HLS grades can be used as gas permeable materials, and Sigrafine HLX and isotropic graphite grades can be used as gas impermeable materials. All of these grades are available from SGL Carbon GmbH in Germany.

[0069] In some embodiments, the channel 110 may include a heating zone, a high-temperature reaction zone, and a cooling zone. The heating zone may be characterized by an increase in the temperature of the carbonaceous material in the flow direction when the graphitization furnace 100 is in use. The high-temperature reaction zone may be characterized by a carbonaceous material having a temperature of at least 80% of the maximum temperature achievable in the graphitization furnace 100. The cooling zone may be characterized by a decrease in the temperature of the carbonaceous material in the flow direction when the graphitization furnace 100 is in use. In some embodiments, the heating zone may be located adjacent to the raw material inlet 160, and / or the cooling zone may be located adjacent to the product outlet 170. In some embodiments, the high-temperature reaction zone may be located between the heating zone and the cooling zone.

[0070] In some embodiments, the gas outlet can be located in the heating zone and / or the high-temperature reaction zone. Placing the gas outlet in the high-temperature reaction zone can allow for the removal of ash compounds with high boiling points (e.g., carbides) because these can exist only in gaseous form in the high-temperature reaction zone. Placing the gas outlet in the heating zone, in particular in a vertical graphitization furnace 100, can allow for flushing the channel 110 from bottom to top when an inert gas or purge gas is fed into the channel in the cooling zone.

[0071] Therefore, for efficient ash removal, it may be advantageous to make a section of channel 110 near the gas removal system or outlet gas permeable. Thus, in some embodiments, at least one gas permeable discrete plate-shaped wall segment can be located in the heating zone and / or high-temperature reaction zone. Furthermore, in some embodiments, channel 110 can include at least one gas inlet in the cooling zone or high-temperature reaction zone. Thus, in some embodiments, at least one gas-impermeable discrete plate-shaped wall segment can be located in the cooling zone, and in particular, all discrete plate-shaped wall segments located in the cooling zone can be gas-impermeable. In some embodiments, at least one gas inlet can be connected to a gas pump and / or pressure regulator, and in particular, the purge gas pump and / or pressure regulator is configured to maintain a pressure above ambient pressure in the graphitization furnace 100. In some embodiments, at least one gas inlet can be connected to a heat exchanger configured to preheat the injected gas.

[0072] As described above, in some embodiments, at least one of the multiple discrete plate-shaped wall segments 140, 150 may contain or be composed of graphite. More specifically, in some embodiments, all of the multiple discrete plate-shaped wall segments 140, 150 may contain or be composed of graphite. In some embodiments, at least one discrete plate-shaped wall segment may contain at least about 80% by weight of graphite, more specifically at least about 90% by weight, and in particular at least about 99% by weight of graphite, relative to the total weight of the discrete plate-shaped wall segments. The graphite may be highly heat-resistant. Alternatively or additionally, at least one discrete plate-shaped wall segment 140, 150 may contain or be composed of CFRC. In some embodiments, at least one discrete plate-shaped wall segment may contain at least about 80% by weight of CFRC, more specifically at least about 90% by weight, and in particular at least about 99% by weight of CFRC, relative to the total weight of the discrete plate-shaped wall segments. Furthermore, CFRC can be highly heat-resistant and can exhibit improved mechanical properties compared to graphite.

[0073] Additionally, graphite can be used as a heating element. For example, an electric current can be applied to a section of channel 110 containing or composed of graphite. The electric current (or electrical energy) can then be converted into thermal energy. Thus, channel 110 itself can heat the carbonaceous material disposed within it. Alternatively, graphite can be used as an electrode to apply an electric current to the carbonaceous material. Therefore, in some embodiments, at least one discrete plate-shaped wall segment can be a heating element or an electrode. Also, CFRC can be used as a heating element or as an electrode for applying an electric current to the carbonaceous material. Therefore, in some embodiments, at least a portion of channel 110 containing or composed of CFRC can be a heating element or an electrode.

[0074] In some embodiments, the wall thickness of the channel 110 can be between approximately 5 mm and approximately 200 mm. In some embodiments, the wall thickness of the multiple discrete plate-shaped wall segments 140, 150 can be between approximately 5 mm and approximately 200 mm. As stated above, the rate of wear at the top of the vertical graphitization furnace 100 can be higher than that at the bottom of the vertical graphitization furnace 100. Additionally, in some embodiments, the channel 110 can include an agitator comprising a shaft and at least one mixing paddle. The agitator can be configured to mix carbonaceous material to prevent caking in the cooling section, among other things. Thus, in some embodiments, at least one mixing paddle can be placed in the cooling zone. However, the mixing action may increase the rate of wear in the cooling zone. Therefore, a higher wall thickness of the discrete plate-shaped wall segments 140, 150 in the lower part of the channel 110 (among other things, the cooling zone) may be beneficial so that the discrete wall segments have an increased lifespan before needing replacement. Therefore, in some embodiments, the wall thickness of at least one discrete plate-shaped wall segment in the cooling zone can be greater than the wall thickness of at least one discrete plate-shaped wall segment in the heating zone, and more specifically, the wall thickness of at least one discrete plate-shaped wall segment in the cooling zone can be between approximately 10% and approximately 200% greater than the wall thickness of at least one discrete plate-shaped wall segment in the heating zone.

[0075] Furthermore, as described above, graphite, and by extension the discrete plate-shaped wall segments 140 and 150 containing graphite, can be used as heating elements. Since the amount of thermal energy generated may be proportional to the amount of graphite, it may be beneficial to have a higher wall thickness for the discrete plate-shaped wall segments 140 and 150 in the high-temperature reaction zone compared to the heating zone in order to achieve higher temperatures in the high-temperature reaction zone. Therefore, in some embodiments, the wall thickness of at least one discrete plate-shaped wall segment in the high-temperature reaction zone can be higher than the wall thickness of at least one discrete plate-shaped wall segment in the heating zone, and more specifically, the wall thickness of at least one discrete plate-shaped wall segment in the high-temperature reaction zone can be between approximately 10% and approximately 200% higher than the wall thickness of at least one discrete plate-shaped wall segment in the heating zone.

[0076] In a second embodiment, the disclosure relates to a method of using a graphitization furnace according to any prior embodiment to prepare graphite from carbonaceous raw materials.

[0077] In some embodiments, the method can produce graphite having a degree of graphitization of at least about 46%, more specifically 69%, even more specifically at least about 80%, and in particular at least about 83%.

[0078] The degree of crystallinity of graphite can be described through its degree of graphitization, which can be measured by X-ray diffraction (XRD). The crystalline carbon in graphite forms a multi-layered honeycomb lattice. The distance between the multi-layered honeycomb lattices is given by the parameter "interplane distance d". 002 This is explained by . XRD is the inter-face distance d between multiple grids. 001 It can be used to measure the interplane distance d of 0.3440 nm. 002This corresponds to the interplane distance in a randomly layered graphite structure, and an interplane distance of 0.3354 nm corresponds to the interplane distance in a perfect graphite crystal.

[0079] The interplane distance can be used to calculate the degree of graphitization using the following formula.

[0080] Graphitization degree = (0.3440 nm - d 002 ) / (0.3440nm-0.3354nm)

[0081] A higher degree of graphitization can accommodate a higher maximum discharge capacity.

[0082] In some embodiments, this method makes it possible to produce graphite suitable for use as an anode material (particularly as an anode material for lithium batteries).

[0083] In some embodiments, the method further includes the step of using graphite produced from operating a graphitization furnace (continuously) to produce an anode for a lithium battery.

[0084] Although the present invention is defined in the appended embodiments, it should be understood that the present invention may also be defined (alternatively) according to the following embodiments.

[0085] 1. A graphitization furnace (100) configured to graphitize particulate carbonaceous material, wherein the graphitization furnace (100) is The raw material inlet (160) and the product outlet (170), A channel (110) connecting the raw material inlet (160) and the product outlet (170) Includes, The channel (110) includes an upstream section (120) closer to the raw material inlet (160) and a downstream section (130) closer to the product outlet (170). Both the upstream section (120) and the downstream section (130) include multiple discrete plate-shaped wall segments (140), (150), A graphitization furnace (100) having both an upstream section (120) and a downstream section (130) with a polygonal cross-sectional shape.

[0086] 2. The graphitization furnace (100) according to Embodiment 1, wherein the channel includes a central channel axis (200), and the upstream section (120) and the downstream section (130) are arranged along the central channel axis (200).

[0087] 3. The cross-sectional shape of the upstream section (120) and / or downstream section (130) is a polygon having n corners, where n is an integer between 3 and 12, as described in any prior embodiment of the graphitization furnace (100).

[0088] 4. A graphitization furnace (100) according to any prior embodiment, wherein the cross-sectional shape is formed by a plurality of discrete plate-shaped wall segments (140), (150).

[0089] 5. The graphitization furnace (100) is configured such that the material flow within the graphitization furnace (100) is gravity-assisted, as described in any prior embodiment.

[0090] 6. The graphitization furnace (100) is a vertical graphitization furnace (100) as described in any prior embodiment.

[0091] 7. The graphitization furnace (100) is the graphitization furnace (100) according to any prior embodiment, comprising an isolation structure surrounding the channel (110).

[0092] 8. A graphitization furnace (100) according to any prior embodiment, wherein at least two adjacent discrete plate-shaped wall segments (140), (150) of a plurality of discrete plate-shaped wall segments are connected by at least one joint, in particular at least one removable joint.

[0093] 9. A graphitization furnace (100) according to Embodiment 8, wherein at least one joint includes a dowel joint, a miter joint, a cross-dowel joint, or a dovetail joint.

[0094] 10. A graphitization furnace (100) according to Embodiment 8 or 9, wherein at least one joint includes a screw, more specifically a carbonaceous screw, and in particular a screw including graphite or carbon fiber reinforced carbon (CFRC).

[0095] 11. A graphitization furnace (100) according to any one of embodiments 8 to 10, wherein at least one joint includes a clamp.

[0096] 12. A graphitization furnace (100) according to any one of embodiments 8 to 11, wherein a plurality of plate-shaped wall segments (140), (150) are joined together by wrapping or clamping, in particular by wrapping with graphite fibers and / or carbon fibers.

[0097] 13. A graphitization furnace (100) according to any one of embodiments 8 to 12, wherein at least one joint is sealed.

[0098] 14. The joint comprises pitch, graphite mat, carbon mat, carbon felt, and / or graphite felt, as described in any one of embodiments 8 to 13, graphitization furnace (100).

[0099] 15. A graphitization furnace (100) according to any prior embodiment, wherein at least one discrete plate-shaped wall segment includes a high-temperature resistant hard coating, and in particular, all discrete plate-shaped wall segments of the downstream section (130) include a high-temperature resistant hard coating.

[0100] 16. A graphitization furnace (100) according to any prior embodiment, wherein at least one of the multiple discrete plate-shaped wall segments (140), (150) is gas permeable.

[0101] 17. A graphitization furnace (100) according to any prior embodiment, wherein the first discrete plate-shaped wall segment of the depicted channel (110) is gas permeable and the second discrete plate-shaped wall segment is gas impermeable.

[0102] 18. The graphitization furnace (100) is the graphitization furnace (100) according to any prior embodiment, including a gas outlet.

[0103] 19. A graphitization furnace (100) according to any prior embodiment, wherein the gas outlet is a tube extending through an isolation structure.

[0104] 20. The channel is a graphitization furnace (100) according to any prior embodiment, comprising a heating zone, a high-temperature reaction zone, and a cooling zone.

[0105] 21. A graphitization furnace (100) according to Embodiment 20, wherein a heating zone is located adjacent to a raw material inlet (160), a cooling zone is located adjacent to a product outlet (170), and / or a high-temperature reaction zone is located between the heating zone and the cooling zone.

[0106] 22. The graphitization furnace (100) according to embodiment 20 or 21, wherein the gas outlet is located in the heating zone and / or high-temperature reaction zone.

[0107] 23. A graphitization furnace (100) according to any one of embodiments 20 to 22, wherein at least one gas-permeable discrete plate-shaped wall segment is disposed in the heating zone and / or high-temperature reaction zone.

[0108] 24. A graphitization furnace (100) according to any one of embodiments 20 to 23, wherein the channel (110) includes at least one gas inlet in a cooling zone or a high-temperature reaction zone.

[0109] 25. A graphitization furnace (100) according to any one of embodiments 20 to 24, wherein at least one gas-impermeable discrete plate-shaped wall segment is provided in the cooling zone, and in particular all discrete plate-shaped wall segments provided in the cooling zone are gas-impermeable.

[0110] 26. The graphitizing furnace (100) according to embodiment 24 or 25, wherein at least one gas inlet is connected to a gas pump and / or pressure regulator, and in particular the purge gas pump and / or pressure regulator is configured to maintain a pressure above ambient pressure inside the graphitizing furnace (100).

[0111] 27. A graphitization furnace (100) according to any one of embodiments 24 to 26, wherein at least one gas inlet is connected to a heat exchanger configured to preheat the injected gas.

[0112] 28. A graphitization furnace (100) according to any prior embodiment, wherein at least one of the plurality of discrete plate-shaped wall segments (140), (150) contains or is composed of graphite, and in particular all of the plurality of discrete plate-shaped wall segments (140), (150) contain or are composed of graphite.

[0113] 29. A graphitization furnace (100) according to any prior embodiment, wherein at least one discrete plate-shaped wall segment is a heating element or electrode.

[0114] 30. A graphitization furnace (100) according to any prior embodiment, wherein the wall thickness of the channel (110) is between approximately 5 mm and approximately 200 mm, and in particular, the wall thickness of the multiple discrete plate-shaped wall segments (140), (150) is between approximately 5 mm and approximately 200 mm.

[0115] 31. The channel (110) is a graphitization furnace (100) according to any prior embodiment, comprising a stirrer including a shaft and at least one mixing paddle.

[0116] 32. A graphitization furnace (100) according to embodiment 31, wherein at least one mixing paddle is located in the cooling zone.

[0117] 33. A graphitization furnace (100) according to any one of embodiments 20 to 32, wherein the wall thickness of at least one discrete plate-shaped wall segment in the cooling zone is greater than the wall thickness of at least one discrete plate-shaped wall segment in the heating zone, more specifically, the wall thickness of at least one discrete plate-shaped wall segment in the cooling zone is greater by a value between about 10% and about 200% compared to the wall thickness of at least one discrete plate-shaped wall segment in the heating zone.

[0118] 34. A graphitization furnace (100) according to any one of embodiments 20 to 33, wherein the wall thickness of at least one discrete plate-shaped wall segment in the high-temperature reaction zone is greater than the wall thickness of at least one discrete plate-shaped wall segment in the heating zone, more specifically, the wall thickness of at least one discrete plate-shaped wall segment in the high-temperature reaction zone is greater by a value between about 10% and about 200% compared to the wall thickness of at least one discrete plate-shaped wall segment in the heating zone.

Claims

1. A graphitization furnace (100) configured to graphitize particulate carbonaceous material, The raw material inlet (160) and the product outlet (170), It includes a channel (110) connecting the raw material inlet (160) and the product outlet (170), The channel (110) includes an upstream section (120) near the raw material inlet (160) and a downstream section (130) near the product outlet (170). Both the upstream section (120) and the downstream section (130) include a plurality of discrete plate-shaped wall segments (140, 150), A graphitization furnace (100) in which both the upstream section (120) and the downstream section (130) have a polygonal cross-sectional shape.

2. The graphitization furnace (100) according to claim 1, wherein the cross-sectional shape of the upstream section (120) and / or the downstream section (130) is a polygon having n corners, where n is an integer between 3 and 12.

3. The graphitization furnace (100) according to claim 1 or 2, wherein the cross-sectional shape is formed by the plurality of discrete plate-shaped wall segments (140, 150).

4. The graphitizing furnace (100) is configured such that the material flow within the graphitizing furnace (100) is gravity-assisted, and in particular, the graphitizing furnace (100) is a vertical type graphitizing furnace (100), according to any one of claims 1 to 3.

5. The graphitizing furnace (100) according to any one of claims 1 to 4, wherein at least two adjacent discrete plate-shaped wall segments (140, 150) of the plurality of discrete plate-shaped wall segments are connected by at least one joint, in particular at least one removable joint.

6. The graphitization furnace (100) according to any one of claims 1 to 5, wherein the at least one joint includes a dowel joint, a miter joint, a cross-dowel joint, or a dovetail joint.

7. The graphitizing furnace (100) according to any one of claims 1 to 6, wherein the at least one joint is sealed, and in particular the joint is sealed by sealing means including pitch, resin, carbon, graphite, graphite mat, graphite foil, expanded graphite, carbon mat, carbon felt and / or graphite felt, carbon fiber, CFRC (carbon fiber reinforced carbon).

8. The graphitization furnace (100) according to any one of claims 1 to 7, wherein at least one discrete plate-shaped wall segment includes a high-temperature resistant hard coating, and in particular, all discrete plate-shaped wall segments of the downstream section (130) include the high-temperature resistant hard coating.

9. The graphitization furnace (100) according to any one of claims 1 to 8, wherein at least one of the plurality of discrete plate-shaped wall segments (140, 150) is gas permeable, and in particular, the first discrete plate-shaped wall segment of the channel (110) is gas permeable, and the second discrete plate-shaped wall segment is gas impermeable.

10. The graphitization furnace (100) according to any one of claims 1 to 9, wherein the channel includes a heating zone, a high-temperature reaction zone, and a cooling zone, the heating zone being located adjacent to the raw material inlet (160), the cooling zone being located adjacent to the product outlet (170), and / or the high-temperature reaction zone being located between the heating zone and the cooling zone.

11. The graphitization furnace (100) according to any one of claims 1 to 10, wherein the gas outlet is located in the heating zone and / or the high-temperature reaction zone.

12. A graphitization furnace (100) according to any one of claims 1 to 11, wherein at least one gas-permeable discrete plate-shaped wall segment is disposed in the heating zone and / or the high-temperature reaction zone.

13. The graphitization furnace (100) according to any one of claims 1 to 12, wherein the wall thickness of the plurality of discrete plate-shaped wall segments (140, 150) is between approximately 5 mm and approximately 200 mm.

14. The graphitizing furnace (100) according to any one of claims 1 to 13, wherein the wall thickness of at least one discrete plate-shaped wall segment in the cooling zone is between approximately 10% and approximately 200% higher than the wall thickness of at least one discrete plate-shaped wall segment in the heating zone.

15. The graphitization furnace (100) according to any one of claims 1 to 14, wherein the wall thickness of at least one discrete plate-shaped wall segment in the high-temperature reaction zone is between approximately 10% and approximately 200% higher than the wall thickness of at least one discrete plate-shaped wall segment in the heating zone.

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