Heat treatment device and production method for highly carbonized product

Abstract

To provide a heat treatment device capable of efficiently obtaining a highly carbonized product, and a production method for the highly carbonized product.SOLUTION: A heat treatment device has: one or more kilns 10, 20, 30 into which superheated vapor or high-temperature combustion gas is injected to a raw material to be treated; an outlet port through which combustible gas generated in the kilns 10, 20, 30 is discharged; a gas flow pathway 70 through which the combustible gas discharged through the outlet port flows; and a recovery part 60 to which the combustible gas which flows through the gas flow pathway 70 is recovered. The gas flow pathway 70 is provided with a tar formation prevention furnace 80 which heats the combustible gas to a temperature of 400°C or higher.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to a heat treatment device and a method for producing a highly carbide material by heat treating a processing material with superheated steam or high-temperature combustion gas. [Background technology]

[0002] Previously, the inventors have proposed a heat treatment apparatus capable of obtaining semi-carbonized or carbonized materials by heat-treating a raw material to be processed with high-temperature superheated steam or high-temperature combustion gas (for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6729906 Summary of the Invention [Problem to be solved by the invention]

[0004] Charcoal is a carbon-based substance obtained by heating raw materials such as biomass in low-oxygen or oxygen-free conditions to pyrolyze (carbonize) them. The higher the degree of carbonization, the more energy can be obtained, so there is a growing need for highly charred materials in which raw materials are decomposed to a higher degree (a greater proportion) of carbon. However, in the above-mentioned Patent Document 1, the heating temperature is low and highly carbonized materials cannot be obtained efficiently. If the heating temperature is increased, the combustible gas generated by the heating process will contain large amounts of components such as hydrocarbons that cause tar. If the temperature of the combustible gas drops during exhaust, the components such as hydrocarbons will liquefy and produce tar. This can cause problems such as the tar adhering to the inner walls of the gas flow passage, reducing combustion efficiency, or the tar leaking out of the device, making it impossible to efficiently obtain highly carbonized materials.

[0005] An object of the present invention is to provide a heat treatment apparatus and a method for producing a highly carbide material that can efficiently produce a highly carbide material. [Means for solving the problem]

[0006] The heat treatment device of the present invention is a heat treatment device having one or more kilns that spray superheated steam or high-temperature combustion gas onto the raw material to be treated, an exhaust port that discharges combustible gas generated in the kiln, a gas flow passage through which the combustible gas discharged from the exhaust port flows, and a recovery section that recovers the combustible gas that has flowed through the gas flow passage, and a tar formation prevention furnace that heats the combustible gas to a temperature of 400°C or higher is provided in the flow passage. The heat treatment device can be switched between a single treatment mode in which superheated steam or high-temperature combustion gas at 400 to 900°C is injected into the kiln to convert the raw material into a highly carbide material in one go, and a double treatment mode in which superheated steam or high-temperature combustion gas at 300 to 450°C is injected into the kiln to heat-treat the raw material, and then the raw material is heated with superheated steam or high-temperature combustion gas at 400 to 900°C, which is higher than the temperature in the first heat treatment, to obtain a highly carbide material.The device can be configured to have a control unit that operates the tar formation prevention furnace when the single treatment mode is selected, and stops the tar formation prevention furnace when the double treatment mode is selected. In the heat treatment device, an activation mode can be further selected in which superheated steam or high-temperature combustion gas at 350 to 550°C, which is higher than the heating temperature of the first heat treatment in the two-pass treatment mode, is injected into the kiln to heat the raw material to be treated, and then the raw material is heated with superheated steam or high-temperature combustion gas at 800 to 900°C, which is higher than the heating temperature of the second heat treatment in the two-pass treatment mode, to obtain activated carbon, and the control unit can be configured to stop the tar formation prevention furnace even when the activation mode is selected. In the heat treatment device, a torrefaction mode can be selected in which superheated steam or high-temperature combustion gas at 200 to 450°C is injected into the kiln to convert the raw material to semi-carbonized material at once, and the heating temperature of the heat treatment in the torrefaction mode is lower than the heating temperatures of the heat treatment in the one-time treatment mode and the two-time treatment mode, and the control unit can be configured to stop the tar formation prevention furnace when the torrefaction mode is selected. In the heat treatment device, the high-temperature gas may be superheated steam. The heat treatment apparatus may be configured such that the heat treatment furnace is filled with superheated steam to create an oxygen-free state inside the heat treatment furnace. A method for producing a highly carbide material according to a first aspect of the present invention includes a carbonization process in which superheated steam or high-temperature combustion gas at 400 to 900°C is sprayed onto the raw material to be processed, a gas heating process in which the combustible gas generated in the carbonization process is heated to 400°C or higher while being circulated, and a high-temperature gas generation process in which the combustible gas is used to generate the superheated steam or the high-temperature combustion gas. A method for producing a highly carbide material according to a second aspect of the present invention comprises a first carbonization step in which superheated steam or high-temperature combustion gas at 300 to 450°C is sprayed onto the raw material to heat-treat the raw material, a cooling step in which the raw material heat-treated in the first carbonization step is cooled, and a second carbonization step in which superheated steam or high-temperature combustion gas at 400 to 900°C, which is higher than the temperature in the first carbonization step, is sprayed onto the raw material cooled in the cooling step to obtain a highly carbide material. [Effects of the Invention]

[0007] According to the present invention, it is possible to provide a heat treatment apparatus and a method for producing a highly carbide material that can efficiently produce a highly carbide material. [Brief explanation of the drawings]

[0008] [Figure 1] 1 is a plan cross-sectional view of a heat treatment apparatus according to an embodiment of the present invention. [Figure 2]1 is a side cross-sectional view of a heat treatment apparatus according to an embodiment of the present invention. [Figure 3] 1 is a front view of a heat treatment apparatus according to an embodiment of the present invention; [Figure 4] 1 is a configuration diagram showing the entire heat treatment apparatus according to an embodiment of the present invention; [Figure 5] FIG. 10 is a diagram for explaining a heat treatment mode according to the embodiment. [Figure 6] 10A and 10B are diagrams for explaining a heating process operation in a torrefaction mode according to the embodiment. [Figure 7] 10A and 10B are diagrams for explaining a heat treatment operation in a one-time treatment mode according to the present embodiment. [Figure 8] 10A and 10B are diagrams for explaining a first heat treatment operation in a two-time treatment mode according to the present embodiment. [Figure 9] 10A and 10B are diagrams for explaining a second heat treatment operation in a two-time treatment mode according to the present embodiment. [Figure 10] FIG. 10 is a diagram for explaining the first heat treatment operation in the activation mode according to the present embodiment. [Figure 11] FIG. 10 is a diagram illustrating a second heat treatment operation in an activation mode according to the present embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] The heat treatment device according to the present invention will be described below with reference to the drawings. Materials to be heat-treated (hereinafter referred to as "raw materials") that can be used with the heat treatment device according to the present invention include wood materials and organic resources of biological origin generated at wood processing plants and intermediate waste treatment plants, as well as plants, algae, food waste, chicken manure, livestock excrement, urban sludge, sewage sludge, construction waste, food waste, and carbon-containing waste plastics. The heat treatment device according to the present invention can also be used for heat treatment, including drying, semi-carbonization, or carbonization, of various organic or inorganic raw materials and products used in production plants. Furthermore, the heat treatment device according to the present invention can heat the raw materials continuously or in a batch process.

[0010] The heat treatment device according to this embodiment allows selection of multiple heat treatment modes. By heating and carbonizing the raw material according to the heat treatment mode, semi-carbonized material, carbide, highly carbonized material, and activated carbon can be obtained. In this embodiment, semi-carbonized material is defined as material containing less than 30% fixed carbon, carbide as material containing 30% or more but less than 60% fixed carbon, highly carbonized material is defined as material containing 60% or more but less than 80% fixed carbon, and activated carbon as material containing 80% or more fixed carbon. Generally, semi-carbonized material can be obtained by heat-treating the raw material at a relatively low temperature of 200-350°C, carbide as material containing 350-550°C, highly carbonized material can be obtained by heat-treating the raw material at a relatively high temperature of 400-900°C, and activated carbon as material containing 800-900°C. As the heating temperature increases, components such as cellulose and lignin are pyrolyzed and converted into carbon, resulting in a higher proportion of fixed carbon in carbonized materials compared to semi-carbonized materials, a higher proportion of fixed carbon in highly carbonized materials compared to carbonized and semi-carbonized materials, and a higher proportion of fixed carbon in activated carbon compared to semi-carbonized, carbonized, and highly carbonized materials.

[0011] Fig. 1 is a plan cross-sectional view of the heat treatment device 1 according to this embodiment, taken along line II in Fig. 2. Fig. 2 is a side cross-sectional view of the heat treatment device 1 according to this embodiment, taken along line II-II in Fig. 1. Fig. 3 is a front view of the heat treatment device 1 according to this embodiment.

[0012] As shown in FIGS. 2 and 3, the heat treatment apparatus 1 has a first kiln 10, a second kiln 20, a third kiln 30, and a stand 40. The stand 40 is a platform on which the first kiln 10, the second kiln 20, and the third kiln 30 are placed, and has a three-tiered structure. In this embodiment, as shown in FIGS. 2 and 3, the first kiln 10 is placed on the upper tier of the stand 40, the second kiln 20 is placed on the middle tier of the stand 40, and the third kiln 30 is placed on the lower tier of the stand 40. As a result, the heat treatment apparatus 1 has a structure in which the first kiln 10, the second kiln 20, and the third kiln 30 are arranged vertically. Meanwhile, the first kiln 10, second kiln 20, and third kiln 30 are connected in series via discharge chutes 110 and 210. The raw material fed into the first kiln 10 is heated while being transported through the first kiln 10, second kiln 20, and third kiln 30, and then discharged from the third kiln 30 as a highly carbide, carbide, or semi-carbide. The first kiln 10 mainly dries the raw material, while the second kiln 20 and third kiln 30 mainly carbonize, carbonize, or semi-carbonize the raw material. The configurations of the first kiln 10, second kiln 20, and third kiln 30 are described below.

[0013] The first kiln 10 has a heat treatment furnace 11 for heat-treating the raw material to be treated. The length of the heat treatment furnace 11 is not particularly limited, but is set to 8 m to 12 m in this embodiment. The inner width of the heat treatment furnace 11 is also not particularly limited, but is set to 0.5 m to 2.0 m in this embodiment. A raw material inlet (hopper) 16 for charging the raw material to be treated is provided at one end of the heat treatment furnace 11, and a raw material outlet 17 for discharging the raw material to be treated into the second kiln 20 is provided at the other end. In addition, within the heat treatment furnace 11, as shown in FIG. 1, a pair of screw conveyors 12, 13 and a pair of nozzle pipes 14, 15 are arranged in parallel.

[0014] Of the pair of screw conveyors 12, 13, the first screw conveyor 12 rotates right (clockwise) to transport the raw materials to be processed from the raw material inlet 16 to the raw material outlet 17 of the heat treatment furnace 11. The second screw conveyor 13 rotates left (counterclockwise) to transport the raw materials to be processed from the raw material inlet 16 to the raw material outlet 17 of the heat treatment furnace 11. As shown in FIGS. 1 to 3 , the first screw conveyor 12 and the second screw conveyor 13 are arranged side by side, and when viewed from above from the raw material inlet 16 side toward the raw material outlet 17 side, the second screw conveyor 13 is arranged to the right of the first screw conveyor 12. The pair of screw conveyors 12, 13 are rotated in each direction by the drive of a motor 100.

[0015] A pair of nozzle pipes 14, 15 are disposed within the heat treatment furnace 11. As shown in FIGS. 1 and 2, the first nozzle pipe 14 and the second nozzle pipe 15 extend within the heat treatment furnace 11, and one end of each pipe is connected to a superheated steam generator 50. The first nozzle pipe 14 and the second nozzle pipe 15 are provided with outlets at predetermined intervals along their extension direction, and high-temperature superheated steam (200 to 700°C) generated by the superheated steam generator 50 is ejected from the outlets to heat-treat the raw material within the heat treatment furnace 11. The superheated steam generator 50 can also generate steam instead of or in addition to the superheated steam, and the generated steam can also be supplied to the heat treatment furnace 11.

[0016] The first nozzle piping 14 and the second nozzle piping 15 are arranged parallel to the first screw conveyor 12 and the second screw conveyor 13. Specifically, the first nozzle piping 14 is arranged outside the first screw conveyor 12, that is, on the left side of the first screw conveyor 12 when viewed from above from the raw material inlet 16 side toward the raw material discharge outlet 17 side. Similarly, the second nozzle piping 15 is arranged outside the second screw conveyor 13, that is, on the right side of the second screw conveyor 13 when viewed from above from the raw material inlet 16 side toward the raw material discharge outlet 17 side.

[0017] In other words, in this embodiment, a pair of nozzle pipes 14, 15 is disposed on the left side of the right-rotating (clockwise) first screw conveyor 12 and on the right side of the left-rotating (counterclockwise) second screw conveyor 13. This is because the raw materials to be processed tend to gather on the side opposite to the rotation direction of the screw conveyors 12, 13, and by disposing a pair of nozzle pipes 14, 15 on the side opposite to the rotation direction of the screw conveyors 12, 13, respectively, the raw materials to be processed that gather on the side opposite to the rotation direction of the screw conveyors 12, 13 can be efficiently heat-treated.

[0018] 2, the first nozzle pipe 14 and the second nozzle pipe 15 are disposed above the first screw conveyor 12 and the second screw conveyor 13, and are configured to eject superheated steam downward or downwardly. This allows the pair of nozzle pipes 14, 15 to eject superheated steam toward the raw material to be processed without interfering with the rotation of the screw conveyors 12, 13.

[0019] Furthermore, in the heat treatment apparatus 1 according to this embodiment, the second kiln 20 and the third kiln 30 also have pairs of screw conveyors 22, 23, 32, 33 and pairs of nozzle pipes 24, 25, 34, 35 in the heat treatment furnaces 21, 31, respectively, similarly to the first kiln 10. That is, in the second kiln 20 and the third kiln 30, the first screw conveyors 22, 32 and the second screw conveyors 23, 33, and the first nozzle pipes 24, 34 and the second nozzle pipes 25, 35 are also arranged in parallel, with the first nozzle pipes 24, 34 arranged on the left side of the first screw conveyors 22, 32 that rotate right (clockwise), and the second nozzle pipes 25, 35 arranged on the right side of the second screw conveyors 23, 33 that rotate left (counterclockwise). Furthermore, the first nozzle pipes 24, 34 and the second nozzle pipes 25, 35 are disposed above the first screw conveyors 22, 32 and the second screw conveyors 23, 33. In the second kiln 20 and the third kiln 30, by disposing the nozzle pipes 24, 25, 34, 35 on the side opposite the rotation direction of the screw conveyors 22, 23, 32, 33, respectively, the raw materials brought to the side opposite the rotation direction of the screw conveyors 22, 23, 32, 33 can be efficiently heat-treated.

[0020] In the heat treatment apparatus 1, the heat treatment furnace 11 of the first kiln 10 and the heat treatment furnace 21 of the second kiln 20 are connected via a discharge chute 110. The raw material to be treated transported to the raw material discharge port 17 of the heat treatment furnace 11 of the first kiln 10 passes through the raw material discharge port 17, the discharge chute 110, and the raw material inlet 26 of the second kiln 20 in that order, and is then transported into the heat treatment furnace 21 of the second kiln 20. In the heat treatment furnace 21 of the second kiln 20, the raw material to be treated is transported from the raw material inlet 26 side to the raw material discharge port 27 side by a pair of screw conveyors 22, 23, and is then transported to the raw material discharge port 27 of the heat treatment furnace 21. In the heat treatment apparatus 1 according to this embodiment, the heat treatment furnace 21 of the second kiln 20 and the heat treatment furnace 31 of the third kiln 30 are connected via a discharge chute 210, and the raw materials to be treated are transported into the heat treatment furnace 31 of the third kiln 30 through the raw material discharge port 27 of the heat treatment furnace 21 of the second kiln 20, the discharge chute 210, and the raw material inlet 36 of the third kiln 30 in that order. The raw materials to be treated are then transported through the heat treatment furnace 31 of the third kiln 30 from the raw material inlet 36 side to the raw material discharge port 37 side by a pair of screw conveyors 32, 33, and are discharged to the outside through the raw material discharge port 37 of the heat treatment furnace 31. The discharge chutes 110, 210 and the raw material discharge ports 17, 27, 37 may be provided with opening and closing valves for opening and closing them.

[0021] A treated material discharge mechanism may be provided below the raw material discharge port 37 of the third kiln 30 to lower the temperature of the highly carbide, carbide, and semi-carbide materials discharged from the raw material discharge port 37 in an oxygen-free state to a temperature at which they will not burn in the atmosphere (i.e., a non-spontaneous combustion temperature) and discharge them to the outside. In this case, the treated material discharge mechanism is equipped with a discharge conveyor having a total length of about 3 m (preferably about 2 to 5 m), and the treated raw materials that have been heat-treated and reduced in volume by the heat treatment device 1 are Steam and By gradually transporting the raw material after expelling oxygen with superheated steam, the temperature of the raw material can be lowered to below 100°C (below the ignition point).

[0022] Furthermore, because each component of the heat treatment device 1 is used at high temperatures, the periphery can be made of heat-resistant materials (for example, stainless steel or heat-resistant steel), and the interior can be made of strong bricks or heat-resistant and wear-resistant ceramics for ultra-high temperatures. Usually, the shell is made of stainless steel, and the exterior is insulated with high-temperature ceramic fiber or the like.

[0023] 4, the heat treatment device 1 according to this embodiment includes a superheated steam generator 50, a combustion furnace 60, a gas flow passage 70, a flow path switching unit 71, a tar formation prevention furnace 80, a control unit 90, an operation unit 120, and a chimney 130. Note that FIG. 4 is a configuration diagram showing the entire heat treatment device 1 according to this embodiment.

[0024] Specifically, in the heat treatment apparatus 1, the exhaust pipe 19 of the first kiln 10, the exhaust pipe 29 of the second kiln 20, and the exhaust pipe 39 of the third kiln are each connected to a gas flow passage 70. The gas flow passage 70 is also connected to the combustion furnace 60. As a result, the combustible gas generated in the first kiln 10, the second kiln 20, and the third kiln 30 is discharged from the respective exhaust pipes 19, 29, and 39 into the gas flow passage 70 and sent to the combustion furnace 60.

[0025] Furthermore, in this embodiment, as shown in FIG. 4 , a flow path switching unit 71 and a tar formation prevention furnace 80 are provided in the gas flow path 70 of the heat treatment device 1. The tar formation prevention furnace 80 is a device such as a burner that heats the combustible gas flowing through the gas flow path 70 to 400°C or higher. The combustible gas generated in the kilns 10, 20, and 30 contains tar-causing components such as hydrocarbons. When the combustible gas is cooled, the hydrocarbons and other components liquefy to generate tar. This tar may adhere to the inner walls of the gas flow path 70, reducing the overall combustion efficiency. Furthermore, when the heat treatment device 1 is shut down, the tar formation prevention furnace 80 heats the combustible gas flowing through the gas flow path 70, suppressing the generation of tar due to the aggregation of hydrocarbons and other components contained in the combustible gas. This allows the high-energy combustible gas, including the hydrocarbons that serve as an energy source, to be sent directly to the combustion furnace 60, thereby further improving the combustion efficiency in the combustion furnace 60.

[0026] The flow path switching unit 71 can be configured, for example, by a three-way valve or a diaphragm valve, and switches the flow path to allow the combustible gas generated in the kilns 10, 20, and 30 and discharged into the gas flow passage 70 to flow to the combustion furnace 60 either via the tar formation prevention furnace 80 or without passing through the tar formation prevention furnace 80. In this embodiment, the flow path switching unit 71 operates under the control of the control unit 90.

[0027] Furthermore, the heat treatment device 1 according to this embodiment has a control unit 90 that controls the operations of the flow path switching unit 71, the combustion furnace 60, and the tar formation prevention furnace 80. In particular, in this embodiment, the control unit 90 can heat treat the raw material to be treated in four modes, namely, torrefaction mode, single treatment mode, double treatment mode, and activation mode, as treatment modes for obtaining semi-carbonized material, highly carbonized material, or activated carbon, as shown in Fig. 3. Note that Fig. 5 is a diagram for explaining the heat treatment modes that can be performed in this embodiment.

[0028] As shown in Figure 5, the torrefaction mode is a mode for obtaining semi-carbide products through a single heat treatment. Superheated steam at 200 to 450°C is ejected into kilns 10, 20, and 30 to produce semi-carbide from the raw material through a single heat treatment. The single-treatment mode is a mode for obtaining highly carbide products through a single heat treatment. Superheated steam at 400 to 900°C is ejected into kilns 10, 20, and 30 to produce highly carbide from the raw material through a single heat treatment. In contrast, the double-treatment mode is a mode for obtaining highly carbide products through a first heat treatment, followed by cooling (leaving at room temperature) the heat-treated raw material (carbonized or semi-carbonized raw material), and then performing a second heat treatment to obtain highly carbide. Specifically, in the double-treatment mode, superheated steam at 300 to 450°C is injected into the kilns 10, 20, and 30 in the first heat treatment, and superheated steam at 400 to 900°C, higher than that in the first heat treatment, is injected into the kilns 10, 20, and 30 in the second heat treatment. This produces highly carbide from the raw material through two heat treatments. Furthermore, the activation mode is a mode in which two heat treatments are performed, similar to the double-treatment mode, but at a higher heating temperature than in the double-treatment mode to obtain activated carbon. Specifically, in the activation mode, superheated steam at 350 to 550°C is injected into the kilns 10, 20, and 30 in the first heat treatment, and superheated steam at 800 to 900°C, higher than that in the first heat treatment, is injected into the kilns 10, 20, and 30 in the second heat treatment. Furthermore, in the activation mode, the heating temperatures for the first and second heat treatments are set higher than in the double-treatment mode. 5, in the single-pass mode and the double-pass mode, the products mainly (more than half) are highly carbide, but some of the products may also include substances classified as semi-carbide, activated carbon, etc. Similarly, in the activation mode, the products mainly include activated carbon, but some of the products may also include substances classified as semi-carbide, highly carbide, etc. In this embodiment, the control unit 90 changes the operation and combustion temperature of the flow path switching unit 71, the combustion furnace 60, and the tar formation prevention furnace 80 depending on whether the torrefaction mode, the single-pass mode, the double-pass mode, or the activation mode is performed.The operation of the heat treatment device 1 in each mode will be described below.

[0029] First, the torrefaction mode will be described in detail. FIG. 6 is a diagram illustrating an example of the operation of the heat treatment device 1 in the torrefaction mode. When an operator operates the operation unit 120 to select the torrefaction mode, the control unit 90 controls the operation of the combustion furnace 60 so that superheated steam at 200 to 450°C is generated from the superheated steam generator 50. Specifically, under the control of the control unit 90, the combustion furnace 60 uses fuels such as heavy oil, light oil, LPG, LNG, hydrogen, and biofuel, as well as combustible gases generated in the kilns 10, 20, and 30, to generate high-temperature combustion gas for generating superheated steam in the superheated steam generator 50, and sends the generated high-temperature combustion gas to the superheated steam generator 50. As a result, the superheated steam generator 50 converts water into superheated steam at 200 to 450°C, which can be sprayed from the first nozzle pipes 14, 24, and 34 and the second nozzle pipes 15, 25, and 35 of the kilns 10, 20, and 30. The control unit 90 also operates the motor 100 to transport the raw material fed into the first kiln 10 through the kilns 10, 20, and 30 in that order, whereby the raw material is converted into semi-carbonized material by heat treatment with superheated steam and is discharged from the third kiln 30. For example, in the example shown in FIG. 6, 2000 kg / H of raw material is heat-treated in torrefaction mode, thereby producing 1400 to 1600 kg / H of semi-carbonized material.

[0030] In the torrefaction mode, the control unit 90 does not operate the tar formation prevention furnace 60, and controls the switching of the flow path switching unit 71 so that the combustible gas flowing through the gas flow path 70 does not pass through the tar formation prevention furnace 80, as shown in Fig. 6. In Fig. 6, the flow path of the gas flow path through which the combustible gas flows is shown in black, and the flow path of the gas flow path through which the combustible gas does not flow is shown in gray (the same applies to Figs. 7 to 11 described below). In the torrefaction mode, the heating temperature at which the raw material is heat-treated is low, so hydrocarbons (components that cause tar generation) contained in the raw material are less likely to gasify and be contained in the combustible gas, and therefore problems caused by tar, as described below, are less likely to occur.

[0031] Next, the single-pass processing mode will be described. FIG. 7 is a diagram illustrating the operation of the heat treatment device 1 in the single-pass processing mode. When an operator operates the operating unit 120 to select the single-pass processing mode, the control unit 90 controls the operation of the flow path switching unit 71, the tar formation prevention furnace 80, and the combustion furnace 60 according to the single-pass processing mode. Specifically, as shown in FIG. 7, in the single-pass processing mode, the control unit 90 generates combustion gas at 850 to 1000°C in the combustion furnace 60, causing the superheated steam generator 50 to heat water at 20°C to generate superheated steam at 400 to 900°C, which is then sprayed into each kiln 10, 20, and 30. In this operational example, when the raw material is heat-treated in the kilns 10, 20, and 30, combustible gas at approximately 250 to 400°C is generated due to carbonization of the raw material. As shown in FIG. 7, the control unit 90 controls the flow path switching unit 71 located on the gas flow path 70 to switch the gas flow path 70 so that the combustible gas passes through the tar formation prevention furnace 80. As a result, the combustible gas proceeds to the tar formation prevention furnace 80, where it is heated to a temperature of 400°C or higher, and is sent to the combustion furnace 60 in a high-temperature state, still containing components such as hydrocarbons that cause tar, where it can be used as fuel.

[0032] When converting raw material into a highly carbide material in one go in the single-processing mode, the raw material is heated with superheated steam at a relatively high temperature of 400 to 900°C. In this case, the combustible gas (carbonized gas) generated from the raw material contains many hydrocarbons and other components derived from the oil content of the raw material. If the temperature of this combustible gas containing many hydrocarbons and other components is lowered to, for example, 350°C or below when it is discharged from the exhaust ports 18, 28, and 38 and flows into the gas flow passage 70, the hydrocarbons and other components contained in the combustible gas will liquefy, producing tar. This tar will adhere to the inner wall surfaces of the gas flow passage 70, thereby reducing the combustion efficiency of the raw material. Therefore, in this embodiment, the control unit 90 operates the tar formation prevention furnace 80 in the single-pass processing mode, and causes the flow path switching unit 71 to direct the combustible gas flowing through the gas flow passage 70 through the tar formation prevention furnace 80, where it is heated to 400°C or higher. This prevents hydrocarbons contained in the combustible gas from coagulating and generating tar, and allows the combustible gas to be sent to the combustion furnace 60 in a state containing a large amount of hydrocarbons (a state in which the hydrocarbons are not liquefied as tar). Because hydrocarbons have combustion energy, sending combustible gas containing a large amount of hydrocarbons to the combustion furnace 60 can further improve the combustion efficiency in the combustion furnace 60. For example, in the example shown in FIG. 7, 2000 kg / H of raw material is heat-treated in the single-pass processing mode, resulting in 500 to 800 kg / H of highly carbide.

[0033] Next, the two-pass treatment mode will be described. FIG. 8 is a diagram illustrating the operation of the heat treatment device 1 in the first heat treatment in the two-pass treatment mode, and FIG. 9 is a diagram illustrating the operation of the heat treatment device 1 in the second heat treatment in the two-pass treatment mode. When an operator operates the operation unit 120 to select the two-pass treatment mode, the control unit 90 first controls the combustion furnace 60 so that the superheated steam generator 50 generates superheated steam at 300 to 450°C, as shown in FIG. 8. In addition, in the first heat treatment, the control unit 90 stops the tar formation prevention furnace 80 and controls the flow path switching unit 71 so that the combustible gas generated in the kilns 10, 20, and 30 is sent to the combustion furnace 60 without passing through the tar formation prevention furnace 80, as shown in FIG. In the first heat treatment, the raw material is heated at a relatively low temperature of 300-450°C, which makes it difficult for hydrocarbons contained in the raw material to gasify. Because the combustible gas does not contain many hydrocarbons, tar is unlikely to be generated even at low combustible gas temperatures, reducing the need to heat the combustible gas using the tar formation prevention furnace 80. In the first heat treatment in the double-processing mode, most of the raw material is converted into low-carbon material (carbonized material with a low fixed carbon content). Most of the hydrocarbons contained in the raw material remain in the raw material and form part of the low-carbon material when the raw material is converted into low-carbon material by heat treatment. For example, in the example shown in Figure 8, 2000 kg / H of raw material is subjected to the first heat treatment in the double-processing mode, resulting in 850-1400 kg / H of low-carbon material.

[0034] Furthermore, in the two-time treatment mode, the low-carbonized material produced in the first heat treatment is removed from the heat treatment device 1 and left (cooled) at room temperature or other temperature for a certain period of time. The cooling time and the temperature after cooling are not particularly limited, but it is preferable to lower the temperature of the low-carbonized material to 100°C or below (or below the ignition point), for example. By removing the low-carbonized material from the heat treatment device 1 and leaving it for a certain period of time in this way, the low-carbonized material can be dried and components such as hydrocarbons that cause tar can be fixed in the low-carbonized material. Even if the low-carbonized material is heated at a relatively high temperature in the second heat treatment described below, it is possible to suppress the gasification of tar-causing components such as hydrocarbons.

[0035] In the second heat treatment in the double-treatment mode, the cooled low-carbide material is again fed into the heat treatment device 1 through the raw material inlet 16. In the second heat treatment, the control unit 90 controls the operation of the combustion furnace 60 so that the superheated steam generator 50 emits superheated steam at a higher heating temperature than in the single-treatment mode, specifically, at 400 to 900°C. In this way, by heating the low-carbide material at a relatively high temperature, the low-carbide material can be converted into a more highly carbonized material. For example, in the example shown in FIG. 9, a second heat treatment in the double-treatment mode for 2000 kg / H of low-carbide material can produce a highly carbonized material at 1100 to 1300 kg / H.

[0036] Furthermore, in the double-processing mode, the first heat treatment is performed at a relatively low temperature of 300–450°C, and then the heat-treated raw material is cooled. This reduces the amount of tar contained in the combustible gas generated from the raw material compared to the single-processing mode, in which the raw material is heated all at once with superheated steam at a relatively high temperature of 400–900°C. Specifically, in the double-processing mode, the amount of hydrocarbons and other components that cause tar contained in the combustible gas can be reduced to about one-fifth of that in the single-processing mode, thereby increasing the amount of hydrocarbons and other components contained in the highly charred product after treatment. As a result, the double-processing mode can produce a highly charred product with higher energy than the single-processing mode.

[0037] As described above, in the two-pass treatment mode, the combustible gas contains a smaller amount of components such as hydrocarbons that cause tar compared to the one-pass treatment mode, so even if the temperature of the combustible gas drops when it flows through the gas flow passage 70, it is possible to prevent tar from being generated from the combustible gas and the tar from adhering to the inner wall of the gas flow passage 70. Therefore, in the present embodiment, the control unit 90 can be configured to stop the tar formation prevention furnace 80 in the second heating treatment in the two-pass treatment mode as well, and control the flow path switching unit 71 to send the combustible gas to the combustion furnace 60 without heating it in the gas flow passage 70.

[0038] Next, the activation mode will be described. Fig. 10 is a diagram illustrating the operation of the heat treatment device 1 in the first heat treatment in the activation mode, and Fig. 11 is a diagram illustrating the operation of the heat treatment device 1 in the second heat treatment in the activation mode. When an operator operates the operation unit 120 to select the activation mode, the control unit 90 first controls the combustion furnace 60 so that superheated steam at 350 to 550°C is generated from the superheated steam generator 50, as shown in Fig. 10. Furthermore, in the first heat treatment, the control unit 90 stops the tar formation prevention furnace 80 and controls the flow path switching unit 71 so that the combustible gas generated in the kilns 10, 20, and 30 is sent to the combustion furnace 60 without passing through the tar formation prevention furnace 80, as shown in Fig. 10. In the first heat treatment in the activation mode, the raw material is heated at a relatively low temperature of 350 to 550°C, which makes it difficult for hydrocarbons contained in the raw material to gasify. Because the combustible gas does not contain many hydrocarbons, tar is unlikely to be generated even at low temperatures, reducing the need to heat the combustible gas using the tar formation prevention furnace 80. When the raw material is converted into carbonized material by heat treatment, most of the hydrocarbons contained in the raw material remain in the raw material and form part of the carbonized material. For example, in the example shown in Figure 10, a first heat treatment in the activation mode for 2000 kg / h of raw material can produce 700 to 1100 kg / h of carbonized material.

[0039] In the activation mode, the carbonized material produced in the first heat treatment is removed from the heat treatment device 1 and left (cooled) at room temperature or other temperature for a certain period of time. The cooling time and the temperature after cooling are not particularly limited, but it is preferable to lower the temperature of the carbonized material to 100°C or below (or below the ignition point) as in the two-treatment mode.

[0040] Then, in the second heat treatment in the activation mode, the cooled carbonized material is again introduced into the heat treatment device 1 through the raw material inlet 16. Furthermore, in the second heat treatment in the activation mode, the control unit 90 controls the operation of the combustion furnace 60 so that the superheated steam generator 50 emits superheated steam at a higher temperature than in the second heat treatment in the double treatment mode, specifically, at 800 to 900°C. Thus, in the activation mode, the carbonized material obtained in the first heat treatment can be converted into activated carbon that is more carbonized than the highly carbonized material by heating it at a higher temperature in the second heat treatment. For example, in the example shown in FIG. 11, 2000 kg / H of carbonized material is subjected to the second heat treatment in the activation treatment mode to obtain 700 to 1200 kg / H of activated carbon.

[0041] Furthermore, in the activation mode, similar to the two-pass mode, the first heating step is performed at a relatively low temperature and the second heating step is performed at a relatively high temperature. This reduces the amount of tar contained in the combustible gas generated from the raw material compared to the one-pass mode, in which the raw material is heated all at once with superheated steam at a relatively high temperature of 400 to 900°C. In the activation mode, similar to the two-pass mode, the combustible gas contains fewer components, such as hydrocarbons, that cause tar, compared to the one-pass mode. This reduces the generation of tar from the combustible gas and the adhesion of tar to the inner wall of the gas flow path 70, even if the temperature of the combustible gas drops as it flows through the gas flow path 70. Therefore, in this embodiment, the control unit 90 can be configured to stop the tar formation prevention furnace 80 during the second heating step in the activation mode, similar to the two-pass mode, and control the flow path switching unit 71 to send the combustible gas to the combustion furnace 60 without heating it in the gas flow path 70.

[0042] Furthermore, if the raw material is heated to 850-900°C all at once when producing activated carbon, it will shrink like binchotan charcoal, failing to form micropores or other fine cavities, resulting in the failure to obtain high-performance activated carbon. In activation mode, the first heating process is performed at a temperature of 400-550°C, followed by cooling, which allows the raw material to form and settle micropores and other fine cavities. The material is then heated with superheated steam at 850-900°C, which gasifies the carbon on the outer surface and pore surfaces through the water-gas reaction (C + H2O → CO + H2), resulting in the formation of high-performance activated carbon with pores even finer than micropores.

[0043] The above-described operation example is merely an example of the operation of the heat treatment device 1 according to this embodiment, and the temperature of the superheated steam is not limited to the above-described operation example.

[0044] For example, in the above-described operational example, the tar formation prevention furnace 80 is stopped in the torrefaction mode, the two-pass mode, and the activation mode. However, a temperature sensor can be installed in the gas flow path 70 before the combustion furnace 60, and when the temperature of the combustible gas measured by the temperature sensor is, for example, 300°C or lower, the tar formation prevention furnace 80 can be operated in the torrefaction mode, the two-pass mode, and the activation mode. Furthermore, in the above-described operational example, the tar formation prevention furnace 80 is operated when the one-pass mode is performed. However, a temperature sensor can be installed in the gas flow path 70 before the combustion furnace 60, and when the temperature of the combustible gas in the gas flow path 70 measured by the temperature sensor is lower than 350°C, the tar formation prevention furnace 80 can be operated and the flow path switching unit 71 can be switched so that the combustible gas generated in the kilns 10, 20, and 30 passes through the tar formation prevention furnace 80, thereby heating the combustible gas to 350°C or higher.

[0045] Furthermore, the operator can operate the operation unit 120 to select a heat treatment mode, and information on the selected treatment mode is sent from the operation unit 120 to the control unit 90. As a result, the control unit 90 controls the operations of the flow path switching unit 71, the combustion furnace 60, and the tar formation prevention furnace 80 in accordance with the selected treatment mode.

[0046] As described above, the heat treatment apparatus 1 according to this embodiment includes one or more kilns 10, 20, 30 that spray superheated steam at 400 to 900°C onto the raw material to be treated, exhaust ports 18, 28, 38 that discharge combustible gas generated in the kilns 10, 20, 30, a gas flow passage 70 through which the combustible gas discharged from the exhaust ports 18, 28, 38 flows, and a combustion furnace 60 that recovers the combustible gas that has flowed through the gas flow passage 70. The gas flow passage 70 is provided with a tar formation prevention furnace 80 that heats the combustible gas to a temperature of 400°C or higher. Thus, in the heat treatment apparatus 1 according to this embodiment, by operating the tar formation prevention furnace 80 and heating the combustible gas flowing through the gas flow passage 70 to 400°C or higher, components such as hydrocarbons contained in the combustible gas are prevented from liquefying and generating tar. The combustible gas can be sent to the combustion furnace 60 in a state containing a large amount of components such as hydrocarbons that serve as a combustion energy source. As a result, the combustion efficiency in the combustion furnace 60 can be further improved.

[0047] In addition, in this embodiment, the control unit 90 can switch between a single treatment mode in which superheated steam at 400 to 900°C is sprayed into the kilns 10, 20, and 30 to convert the raw material into a highly carbide material all at once, and a double treatment mode in which superheated steam or high-temperature combustion gas at less than 400°C, more preferably 200 to 350°C, is sprayed into the kilns 10, 20, and 30, and the heat-treated raw material is then reheated with superheated steam or high-temperature combustion gas at 400 to 900°C to obtain a highly carbide material.When the single treatment mode is selected, the tar formation prevention furnace 80 is operated, and when the double treatment mode is selected, the tar formation prevention furnace 80 is stopped. As a result, in the single-processing mode, when the raw material to be processed is heated in a high-temperature mode in which superheated steam at 400 to 900°C is sprayed into the kilns 10, 20, and 30, components such as hydrocarbons that cause tar are easily gasified from the raw material to be processed (because the combustible gas contains a large amount of components such as hydrocarbons), so by operating the tar formation prevention furnace 80 and heating the temperature of the combustible gas to 400°C or higher, adhesion of tar in the gas flow passage 70 can be prevented, and the combustible gas can be sent to the combustion furnace 60 while still containing a large amount of components such as hydrocarbons that cause tar.

[0048] In the two-pass mode, the raw material is heated with superheated steam at a relatively low temperature (300–450°C) during the first heat treatment. The second heat treatment carbonizes the low-carbonized material, which immobilizes tar-causing hydrocarbons and other components. This reduces the amount of tar-causing hydrocarbons and other components contained in the combustible gas. Specifically, the two-pass mode reduces the amount of hydrocarbons and other components contained in the combustible gas to about one-fifth of that in the single-pass mode. This increases the amount of hydrocarbons and other components (or carbon derived from them) in the highly carbonized material after heat treatment, enabling the production of a highly carbonized material with higher energy than the single-pass mode. Furthermore, the two-pass mode can also prevent tar, which is liquefied hydrocarbons and other components contained in the combustible gas, from adhering to the inner wall of the gas flow channel 70, even without heating in the tar formation prevention furnace 80.

[0049] Although the preferred embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the above-described embodiments. Various modifications and improvements can be made to the above-described embodiments, and such modifications and improvements are also included in the technical scope of the present invention.

[0050] For example, in the above-described embodiment, a configuration was exemplified in which the combustible gas generated in the kilns 10, 20, and 30 is recovered in the combustion furnace 60 and combusted to generate high-temperature superheated steam or high-temperature combustion gas that is sprayed back into the kilns 10, 20, and 30. However, instead of the combustion furnace 60, a device can be provided that only recovers the combustible gas without burning it for separate use.

[0051] In the above-described embodiment, the heat treatment of the raw material is performed by ejecting superheated steam, but the present invention is not limited to this configuration, and the heat treatment of the raw material may be performed by ejecting high-temperature combustion gas instead of superheated steam. In the heat treatment device 1 according to the above-described embodiment, the heat treatment may be performed using superheated steam in the first kiln 10, and using high-temperature combustion gas in the second kiln 20 and the third kiln.

[0052] Furthermore, in the above-described embodiment, a configuration in which each kiln 10, 20, 30 is arranged approximately horizontally has been exemplified, but this configuration is not limited to this. Each kiln 10, 20, 30 may be configured to have a downward slope, for example, in the range of 0.2 to 2 degrees, so that the raw material discharge outlet 17, 27, 37 side is lower, or conversely, each kiln 10, 20, 30 may be configured to have an upward slope, for example, in the range of 0.2 to 2 degrees, so that the raw material discharge outlet 17, 27, 37 side is higher.

[0053] Furthermore, in the above-described embodiment, a configuration including the tar formation prevention furnace 80 has been exemplified, but in a configuration in which the single-pass processing mode is not performed, it is possible to use a heat treatment device that does not include the tar formation prevention furnace 80. This is because in modes other than the single-pass processing mode, the combustible gas does not contain large amounts of components such as hydrocarbons that cause tar, so it is possible to omit the tar formation prevention furnace 80 for heating the combustible gas to suppress the generation of tar.

[0054] In addition, in the above-described embodiment, a configuration in which the first kiln 10 has a raw material inlet 16 is exemplified, but in addition to this configuration, it is also possible to configure it to further have a conveyor or the like for feeding the raw material to be processed into the raw material inlet 16.

[0055] Furthermore, in the above-described embodiment, a configuration having three kilns, namely, the first kiln 10, the second kiln 20, and the third kiln 30, is exemplified, but this configuration is not limited to this, and the configuration may be composed of only the first kiln 10 and the second kiln 20, or may be composed of four or more kilns.

[0056] In addition, in the above-described embodiment, a configuration having a pair of screw conveyors is exemplified, but a configuration having a single screw conveyor or three or more screw conveyors may also be used.

[0057] In addition, although the above-described embodiment exemplifies a configuration in which the torrefaction mode can be selected, the present invention is not limited to this configuration and may be configured so that the torrefaction mode is not executed.Similarly, although the above-described embodiment exemplifies a configuration in which the activation mode can be selected, the present invention is not limited to this configuration and may be configured so that the activation mode is not executed.

[0058] Furthermore, in the above-described embodiment, a configuration was exemplified in which, in the two-pass processing mode, the control unit 90 controls the flow path switching unit 71 to stop the tar formation prevention furnace 80 and send the combustible gas generated in the kilns 10, 20, and 30 from the gas flow passage 70 to the combustion furnace 60 without passing through the tar formation prevention furnace 80. However, this configuration is not limited to this, and the operator can operate the operation unit 120 to operate the tar formation prevention furnace 80 even in the two-pass processing mode, for example, in the case of processing raw materials with a high tar content, and control the flow path switching unit 71 so that the combustible gas passes through the tar formation prevention furnace 80. [Explanation of symbols]

[0059] 1...Heat treatment device 10, 20, 30... Kiln 11, 21, 31...Heat treatment furnace 12, 22, 32...1st screw conveyor 13, 23, 33...Second screw conveyor 14, 24, 34...First nozzle piping 15, 25, 35...Second nozzle piping 16,26,36…Raw material input port 17,27,37…raw material discharge port 18, 28, 38...Exhaust port 19, 29, 39...Exhaust pipe 110,210...Discharge chute 40... stand 50...Superheated steam generator 60...Combustion furnace 70...Gas passage 71...Flow path switching section 80...Tar prevention furnace 90...Control unit 100...Motor 120...Operation unit 130...Chimney

Claims

1. one or more kilns that inject hot gases, such as superheated steam or hot combustion gases, onto the raw material to be treated; an exhaust port for discharging combustible gas generated in the kiln; a gas flow passage through which the combustible gas discharged from the exhaust port flows; a recovery unit that recovers the combustible gas that has flowed through the gas flow passage, a tarring prevention furnace for heating the combustible gas to a temperature of 400°C or higher is provided in the gas flow passage;

2. The kiln can be switched between a single treatment mode in which superheated steam or high-temperature combustion gas at 400 to 900°C is injected into the kiln to convert the raw material into a highly carbide material at once, and a double treatment mode in which superheated steam or high-temperature combustion gas at 300 to 450°C is injected into the kiln to heat-treat the raw material, and then the raw material is heat-treated again with superheated steam or high-temperature combustion gas at 400 to 900°C, which is higher than the temperature of the first heat treatment, to obtain a highly carbide material.

2. The heat treatment device according to claim 1, further comprising a control unit that operates the tar formation prevention furnace when the one-time treatment mode is selected, and stops the tar formation prevention furnace when the two-time treatment mode is selected.

3. An activation mode can be further selected in which superheated steam or high-temperature combustion gas at a temperature of 350 to 550°C, which is higher than the heating temperature of the first heat treatment in the two-time treatment mode, is injected into the kiln to heat the raw material to be treated, and then the raw material is heated with superheated steam or high-temperature combustion gas at a temperature of 800 to 900°C, which is higher than the heating temperature of the second heat treatment in the two-time treatment mode, to obtain activated carbon. The heat treatment device according to claim 2 , wherein the control unit stops the tar formation prevention furnace even when the activation mode is selected.

4. Torrefaction mode can be selected, in which superheated steam or high-temperature combustion gas at 200 to 450°C is injected into the kiln to convert the raw material into semi-carbide all at once. the heating temperature of the heat treatment in the torrefaction mode is lower than the heating temperatures of the heat treatment in the one-time treatment mode and the two-time treatment mode, The heat treatment device according to claim 2 , wherein the control unit stops the tar formation prevention furnace when the torrefaction mode is selected.

5. 4. The heat treatment apparatus according to claim 1, wherein the high-temperature gas is superheated steam.

6. The heat treatment apparatus according to claim 4, wherein the heat treatment furnace is filled with superheated steam to create an oxygen-free state inside the heat treatment furnace.

7. a carbonization step in which superheated steam or high-temperature combustion gas at 400 to 900°C is sprayed onto the raw material to be treated; a gas heating step of heating the combustible gas generated in the carbonization step to 400°C or higher when circulating the combustible gas; and a high-temperature gas generating step of generating the superheated steam or the high-temperature combustion gas using the combustible gas.

8. a first carbonization step in which superheated steam or high-temperature combustion gas at 300 to 450°C is sprayed onto the raw material to heat-treat the raw material; a cooling step of cooling the processed raw material heat-treated in the first carbonization step; a second carbonization step in which superheated steam or high-temperature combustion gas at a temperature of 400 to 900°C, higher than that in the first carbonization step, is sprayed onto the processed raw material cooled in the cooling step to obtain a highly carbide material.

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