Pyrolysis gasification process

Abstract

The present invention relates to a pyrolysis gasification method for pyrolyzing a raw material in a pyrolysis furnace, and particularly to a technique for controlling the temperature in the pyrolysis furnace. The pyrolysis gasification method pyrolyzes a raw material in a pyrolysis furnace (1) using the heat of a fluidizing medium including a mixture of large-particle-size particles and small-particle-size particles having different average particle diameters, captures small-particle-size particles contained in a pyrolysis gas discharged from the pyrolysis furnace (1) by a solid-gas separation device (6), heats the small-particle-size particles captured by the solid-gas separation device (6) by a heating device (12), and returns the small-particle-size particles heated by the heating device (12) to the pyrolysis furnace (1) through a particle return line (15).

Description

Technical Field

[0001] This invention relates to a pyrolysis gasification method for pyrolyzing raw materials in a pyrolysis furnace, and particularly to a technique for controlling the temperature inside the pyrolysis furnace. Background Technology

[0002] Fluidized bed furnaces, as disclosed in Patent Documents 1 and 2, are used as treatment systems for the pyrolysis and gasification of raw materials such as municipal solid waste and industrial waste. These fluidized bed furnaces are internally divided into a pyrolysis furnace and a media regeneration furnace by partition walls, with the fluidizing medium circulating between the two. This type of fluidized bed furnace is referred to as an internally circulating fluidized bed gasification system.

[0003] From the perspective of preventing global warming, the demand for pyrolysis of waste plastics to recover oil is increasing (Patent Documents 3 and 4). However, recovering oil with high yields is difficult, and there are virtually no commercially successful cases. The aforementioned internal circulating fluidized bed gasification system is a promising technology that can heat and pyrolyze waste plastics in a pyrolysis furnace and recover the organic compounds, i.e., oil, which are liquid at room temperature and pressure, as pyrolysis products.

[0004] In particular, fluidized bed gasification systems with structures that separate the pyrolysis furnace from the media regeneration furnace can recover high concentrations of pyrolysis products. Specifically, the feedstock fed into the pyrolysis furnace is pyrolyzed in the fluidized bed, separating into volatile components and residues (carbides, etc.). The residues, along with the fluidizing medium, are conveyed to the media regeneration furnace, where they are combusted using air supplied from the bottom of the regeneration furnace. The fluidized medium, heated in the regeneration furnace, is then moved back to the pyrolysis furnace, serving as a heat source for the pyrolysis reaction. Because the volatile components generated in the pyrolysis furnace can be recovered as products without including the combustion exhaust gases generated in the regeneration furnace, high concentrations of pyrolysis products can be recovered.

[0005] From the perspective of preventing global warming, it is hoped that chemical recycling, in which the recovered pyrolysis products are used as chemical raw materials, will become widespread. However, one challenge in chemical recycling is the yield of compounds. As chemical raw materials, the types of compounds required are usually limited, therefore, it is necessary to increase the yield of the target compounds.

[0006] On the other hand, the composition of pyrolysis products is mainly affected by the raw materials, temperature, and residence time. When waste materials such as waste plastics are used as raw materials, the raw materials contain a wide variety of compounds. Therefore, the products obtained through pyrolysis are also diverse, reducing their value as chemical raw materials. Thus, it is necessary to control the composition of the products by controlling the temperature and residence time. A pyrolysis furnace consists of the following parts: a thick layer densely containing fluidizing medium; a splash zone above this thick layer where the fluidizing medium and a large amount of gas coexist; and a free space above the splash zone that contains almost no fluidizing medium and is mainly composed of gas. When controlling the pyrolysis temperature, the temperature of the thick layer in the pyrolysis furnace is controlled. The temperature control of the thick layer can be mainly achieved by adjusting the amount of heat transferred from the medium regeneration furnace to the pyrolysis furnace, that is, the circulation rate of the fluidizing medium. The residence time can be controlled by changing the supply rate of fluidizing gas to the pyrolysis furnace.

[0007] To maintain a consistent composition of the pyrolysis products, a certain temperature needs to be maintained for a specific period of time. However, in free space, when an endothermic reaction, i.e., a pyrolysis reaction, proceeds, the temperature drops, making it difficult to maintain. Consequently, it becomes difficult to increase the yield of the compounds required as chemical raw materials. Existing technical documents Patent documents

[0008] Patent Document 1: Japanese Patent No. 4243919. Patent document 2: Japanese Patent No. 6935482. Patent document 3: Japanese Patent Application Publication No. 2002-129169. Patent document 4: Japanese Patent No. 3611306. Summary of the Invention The problem that the invention aims to solve

[0009] Therefore, the present invention provides a pyrolysis gasification method that can improve the yield of the target pyrolysis product by controlling the temperature inside the pyrolysis furnace. Methods for solving problems

[0010] On one hand, a pyrolysis gasification method for pyrolyzing raw materials is provided. This method utilizes the heat of a fluidizing medium comprising a mixture of large and small particles with different average particle sizes to pyrolyze the raw materials in a pyrolysis furnace. A solid-gas separation device captures the small particles contained in the pyrolysis gas discharged from the pyrolysis furnace. A heating device heats the small particles captured by the solid-gas separation device. The heated small particles are then returned to the pyrolysis furnace via a particle return pipeline.

[0011] On one hand, a pyrolysis gasification method for pyrolyzing raw materials is provided. This method utilizes the heat of a fluidizing medium comprising a mixture of large and small particles with different average particle sizes to pyrolyze the raw materials in a pyrolysis furnace. While the fluidizing medium is fluidized, the residue of the raw materials is burned in a medium regeneration furnace. The small particles contained in the pyrolysis gas discharged from the pyrolysis furnace are captured by a first solid-gas separation device. The small particles captured by the first solid-gas separation device are returned to the medium regeneration furnace via a first particle return pipeline. The small particles contained in the combustion exhaust gas discharged from the medium regeneration furnace are captured by a second solid-gas separation device. The small particles captured by the second solid-gas separation device are returned to the pyrolysis furnace via a second particle return pipeline.

[0012] On one hand, a pyrolysis gasification method for pyrolyzing raw materials is provided. This method utilizes the heat of a fluidizing medium comprising a mixture of large and small particles with different average particle sizes to pyrolyze the raw materials in a pyrolysis furnace. While the fluidizing medium is fluidized, the residue of the raw materials is burned in a medium regeneration furnace. The fluidizing medium is transported from the medium regeneration furnace to the pyrolysis chamber through a medium settling chamber. A solid-gas separation device captures the small particles contained in the pyrolysis gas discharged from the pyrolysis furnace. The small particles captured by the solid-gas separation device are returned to the medium settling chamber through a particle return pipeline.

[0013] On one hand, a pyrolysis gasification method for pyrolyzing raw materials is provided. This method utilizes the heat of a fluidizing medium comprising a mixture of large and small particles with different average particle sizes to pyrolyze the raw materials in a pyrolysis furnace. A solid-gas separation device captures the small particles contained in the pyrolysis gas discharged from the pyrolysis furnace. The small particles captured by the solid-gas separation device are returned to the pyrolysis furnace via a particle return pipeline. The particle return pipeline passes through the interior of a medium regeneration furnace and extends to the pyrolysis furnace. The small particles in the particle return pipeline are heated by the combustion of residues from the raw materials within the medium regeneration furnace. Invention Effects

[0014] According to the above aspect, the small-diameter particles heated by the heating device are returned to the pyrolysis furnace. Under the action of the fluidizing gas that fluidizes the fluidizing medium, the high-temperature small-diameter particles are propelled within the pyrolysis furnace and rapidly reach the free space. Therefore, the temperature in the free space is maintained at a high level, allowing the pyrolysis reaction to proceed in the free space. As a result, the yield of the target pyrolysis product can be improved.

[0015] According to the above aspect, the small-diameter particles returned to the media regeneration furnace are heated by combustion within the furnace. The heated small-diameter particles are then propelled through the furnace by the fluidizing gas that fluidizes the fluidizing medium, and are discharged from the furnace along with the combustion exhaust. The high-temperature small-diameter particles contained in the combustion exhaust are captured by the second solid-gas separation device and returned to the pyrolysis furnace. These high-temperature particles are propelled through the pyrolysis furnace by the fluidizing gas that fluidizes the fluidizing medium and rapidly reach the free space. Therefore, the temperature in the free space is maintained at a high level, allowing the pyrolysis reaction to proceed in the free space. This results in an increased yield of the target pyrolysis product.

[0016] According to the above aspect, the small-diameter particles returned to the media settling chamber are mixed with and heated by the high-temperature fluidized medium supplied from the media regeneration furnace. The heated small-diameter particles, along with the fluidized medium, are then fed into the pyrolysis furnace. Under the influence of the fluidizing gas that fluidizes the medium, the small-diameter particles in the fluidized medium are propelled within the pyrolysis furnace and rapidly reach the free space. Therefore, the temperature in the free space is maintained at a high level, allowing the pyrolysis reaction to proceed in the free space. This results in an increased yield of the target pyrolysis product.

[0017] According to the above aspect, the small-diameter particles captured by the solid-gas separation device are conveyed in the particle return pipeline while being heated by combustion in the medium regeneration furnace. The heated small-diameter particles are then returned to the pyrolysis furnace through the particle return pipeline. The high-temperature small-diameter particles are propelled within the pyrolysis furnace by the fluidizing gas that fluidizes the fluidizing medium and rapidly reach the free space. Therefore, the temperature in the free space is maintained at a high level, allowing the pyrolysis reaction to proceed in the free space. This results in an increased yield of the target pyrolysis product. Attached Figure Description

[0018] Figure 1 This is a schematic diagram illustrating one embodiment of a pyrolysis gasification system used for pyrolysis of raw materials. Figure 2 This is a cross-sectional view representing an example of a latent heat storage microcapsule. Figure 3 This is a schematic diagram illustrating another implementation of the pyrolysis gasification system. Figure 4 This is a schematic diagram illustrating another implementation of the pyrolysis gasification system. Figure 5 This is a schematic diagram illustrating another implementation of the pyrolysis gasification system. Figure 6 This is a schematic diagram illustrating another implementation of the pyrolysis gasification system. Figure 7 This is a schematic diagram illustrating another implementation of the pyrolysis gasification system. Detailed Implementation

[0019] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Figure 1 This is a schematic diagram illustrating one embodiment of a pyrolysis gasification system for pyrolyzing raw materials. The pyrolysis gasification system includes a pyrolysis furnace 1 that utilizes the heat of a fluidizing medium to pyrolyze the raw materials. The pyrolysis furnace 1 contains a fluidizing medium. In this embodiment, the fluidizing medium is composed of a mixture of large-diameter particles and small-diameter particles with different average particle sizes.

[0020] To fluidize the fluidizing medium, a fluidizing gas G1 is supplied from the bottom of the pyrolysis furnace 1. The fluidizing medium is fluidized under the action of the fluidizing gas G1, forming a fluidized bed within the pyrolysis furnace 1. A thick layer 2, containing large-diameter particles of the fluidizing medium at high density, forms below the fluidized bed. A free space 3, containing small-diameter particles of the fluidizing medium, is formed above the fluidized bed. In this embodiment, as described later, the pyrolysis reaction occurs not only in the thick layer 2 but also in the free space 3.

[0021] The raw materials to be processed are fed into pyrolysis furnace 1. While being agitated by the swirling flow of the fluidizing medium within pyrolysis furnace 1, the raw materials receive heat from the fluidizing medium and undergo pyrolysis. There are no particular limitations on the raw materials processed by the pyrolysis gasification system; for example, it includes organic materials such as waste plastics. Pyrolysis furnace 1 operates under oxygen-deficient conditions to carry out the pyrolysis of the raw materials. Therefore, the raw materials do not burn within pyrolysis furnace 1.

[0022] The pyrolysis gasification system also includes a solid-gas separation device 6 for capturing small-diameter particles of the fluidizing medium contained in the pyrolysis gas discharged from the pyrolysis furnace 1. The solid-gas separation device 6 is connected to the pyrolysis furnace 1 via a pyrolysis gas delivery pipeline 8. When the raw material is pyrolyzed, pyrolysis gas is generated. This pyrolysis gas is delivered from the pyrolysis furnace 1 to the solid-gas separation device 6 via the pyrolysis gas delivery pipeline 8. The solid-gas separation device 6 is positioned downstream of the pyrolysis furnace 1 in the direction of pyrolysis gas flow. The solid-gas separation device 6 is configured to capture small-diameter particles (fluidizing medium) contained in the pyrolysis gas.

[0023] In this embodiment, the fluidizing medium comprises large-diameter particles and small-diameter particles, with the average particle size of the small-diameter particles being smaller than that of the large-diameter particles. The fluidization state of the fluidizing medium depends on the supply flow rate of the fluidizing gas G1 and the particle size of the fluidizing medium. The flow rate of the fluidizing gas G1 is adjusted to optimize the fluidization state of the particles within the fluidized bed. Generally, the smaller the particle size distribution of the fluidizing medium, the more uniform the particle behavior. In contrast, in this embodiment, by using a fluidizing medium comprising large-diameter and small-diameter particles with different average particle sizes, the large-diameter and small-diameter particles exhibit different fluidization behaviors within the fluidized bed due to the difference in particle size. That is, large-diameter particles facilitate mixing, stirring, and heat transfer in the thick layer 2, while small-diameter particles facilitate dispersion and heat transfer into the free space 3.

[0024] To promote mixing, stirring, and heat transfer in the fluidized bed, it is necessary to increase the flow rate of the fluidizing gas G1 supplied from the bottom of the pyrolysis furnace 1, thereby increasing the fluidization velocity. Therefore, large-diameter particles have an average particle size that does not easily lead to dispersion into the free space 3 even with increased fluidization velocity. In one embodiment, the average particle size of the large-diameter particles is in the range of 300 μm to 600 μm. On the other hand, small-diameter particles have an average particle size that easily disperses into the free space 3. In one embodiment, the average particle size of the small-diameter particles is in the range of 20 μm to 40 μm.

[0025] The solid-gas separation device 6 is configured to capture small-diameter particles contained in the pyrolysis gas discharged from the pyrolysis furnace 1, and is capable of capturing particles with a diameter of 20 μm to 40 μm. Specific examples of the solid-gas separation device 6 include cyclone separators, bag filters, and electrostatic precipitators. While bag filters and electrostatic precipitators can capture particles smaller than 1 μm, they are not necessarily the most optimal choice considering equipment cost, reliability, and safety. On the other hand, although the maximum capture diameter of a cyclone separator is approximately 10 μm, cyclone separators have a simple structure and excellent reliability and safety. Therefore, in this embodiment, a cyclone separator is used as the solid-gas separation device 6. However, the solid-gas separation device 6 is not limited to cyclone separators as long as it can capture particles with a diameter of 20 μm to 40 μm.

[0026] The pyrolysis gasification system also includes: a heating device 12 for heating small-diameter particles captured by the solid-gas separation device 6; and a particle return pipeline 15 for returning the small-diameter particles heated by the heating device 12 to the pyrolysis furnace 1. The heating device 12 is connected to the solid-gas separation device 6 and the particle return pipeline 15, which is connected to the pyrolysis furnace 1. The heating device 12 is positioned between the solid-gas separation device 6 and the particle return pipeline 15. The particle return pipeline 15 extends from the heating device 12 to the pyrolysis furnace 1.

[0027] Examples of heating devices 12 include electric heaters and heat exchangers (e.g., multi-tube heat exchangers, jacketed tubes). The heat source for the heat exchanger can be combustion exhaust gas, high-temperature steam, etc., generated during the process of regenerating the fluidized medium.

[0028] The small-diameter particles, heated by the heating device 12, are returned to the pyrolysis furnace 1 via the particle return line 15. Under the influence of the fluidizing gas G1 that fluidizes the fluidizing medium, the high-temperature small-diameter particles are propelled within the pyrolysis furnace 1 and rapidly reach the free space 3. Therefore, the temperature within the free space 3 is maintained at a high level, allowing the pyrolysis reaction to proceed within the free space 3. This results in an increased yield of the target pyrolysis product.

[0029] The pyrolysis gasification system also includes a gas sealing device 18 to prevent backflow of gas from the pyrolysis furnace 1. The gas sealing device 18 is installed on the particle return line 15. The gas sealing device 18 is provided to prevent a decrease in pyrolysis yield and particle dispersion downstream of the solid-gas separation unit 6. Examples of gas sealing devices 18 include annular seals, rotary valves, and trickle valves, but the gas sealing device 18 is not limited to these examples.

[0030] By appropriately adjusting the operating conditions of the pyrolysis gasification system, the majority (over 50%) of the pyrolysis reaction occurs in the thickened layer 2. When almost all the pyrolysis reaction occurs in the thickened layer 2 (over 90%), the benefit of adding small-diameter particles to the fluidizing medium is minimal, and it would increase equipment investment, making it unsuitable. The amount of pyrolysis reaction in the thickened layer 2 is affected by the raw materials and operating mode. By adding small-diameter particles to the large-diameter particles according to the proportion of unreacted particles in the thickened layer 2, the small-diameter particles can contribute to the pyrolysis reaction in the free space 3.

[0031] In one embodiment, when the material (heat capacity) of the large-diameter particles and the small-diameter particles are the same, the weight ratio of the large-diameter particles to the small-diameter particles is 9:1 to 5:5. This corresponds to a pyrolysis reaction with a pyrolysis amount of 50% to 90% in the thick layer 2 and a pyrolysis amount of 10% to 50% in the free space 3. In other words, to allow the pyrolysis reaction to take place in the free space 3, 10% to 50% of the heat of reaction is supplied to the free space 3. The materials of the large-diameter particles and the small-diameter particles are not particularly limited; for example, silica sand can be used.

[0032] The large and small particles constituting the fluidizing medium can also be made of different materials. In one embodiment, the large particles are made of silica sand, and the small particles can be made of latent heat storage microcapsules as described below.

[0033] Figure 2This is a cross-sectional view illustrating an example of a latent heat storage microcapsule. Latent heat storage microcapsules are heat-storing particles that utilize the latent heat required for a phase change in a material. For example... Figure 2 As shown, the latent heat storage microcapsule has a latent heat storage material 20 and a shell 21 covering the latent heat storage material 20.

[0034] The latent heat storage material 20 is a material that stores the absorbed heat as latent heat when it changes from a solid phase to a liquid phase, and releases the stored heat when it changes from a liquid phase to a solid phase. Examples of such a latent heat storage material 20 include metals such as aluminum and aluminum alloys. The shell 21 is made of a material with a melting point higher than that of the latent heat storage material 20. Examples of materials for the shell 21 include ceramics such as alumina.

[0035] Latent heat storage microcapsules possess a very large heat capacity at the phase change temperature. Therefore, when latent heat storage microcapsules are used as small-diameter particles in the fluidizing medium, they can supply the reaction heat required for pyrolysis in the free space 3, significantly improving the temperature controllability of the free space 3. Specifically, by using latent heat storage microcapsules, the amount of fluidizing medium used can be reduced while increasing the heat supply in the free space 3. In particular, during the phase change of the latent heat storage material 20, the temperature of the free space 3 can be maintained at a constant level at the phase change temperature (e.g., 500°C). That is, by using latent heat storage microcapsules, not only can the amount of fluidizing medium used be significantly reduced, but also, due to their large heat capacity, the free space 3 can be maintained at a high temperature, and the operating temperature of the free space 3 can be controlled at a constant level based on the phase change temperature.

[0036] Figure 3 This is a schematic diagram illustrating another embodiment of the pyrolysis gasification system. Structures and operations not specifically described in this embodiment are similar to those described in the reference diagram. Figure 1 The implementation methods described are the same, so repeated descriptions are omitted.

[0037] The pyrolysis gasification system includes a media regeneration furnace 31, which fluidizes the fluidizing medium while simultaneously burning the residue from the feedstock. In the pyrolysis furnace 1, the fluidization state sometimes deteriorates due to coke adhering to the fluidizing medium and residue accumulation. Therefore, the media regeneration furnace 31 is provided to burn the coke and residue and remove them from the fluidizing medium. In the media regeneration furnace 31, the fluidizing medium is heated by the heat of combustion of the carbon components contained in the feedstock; therefore, this heat is used to heat the fluidizing medium.

[0038] The pyrolysis gasification system also includes: a solid-gas separator 6, which collects small-diameter particles contained in the pyrolysis gas discharged from the pyrolysis furnace 1; a particle return pipeline 37, which returns the small-diameter particles collected by the solid-gas separator 6 to the media regeneration furnace 31; a solid-gas separator 43, which collects small-diameter particles contained in the combustion exhaust gas discharged from the media regeneration furnace 31; and a particle return pipeline 45, which returns the small-diameter particles collected by the solid-gas separator 43 to the pyrolysis furnace 1. In this embodiment, no such separation is provided. Figure 1 The heating device 12 shown.

[0039] Fluidization medium used and reference Figure 1 The described implementation method is the same, including large-diameter particles and small-diameter particles with different average particle sizes. The small-diameter particles can be latent heat storage microcapsules. The media regeneration furnace 31 is connected to the pyrolysis furnace 1 via media conveying channels 47 and 48. The raw material is agitated by the swirling flow of the fluidizing medium within the pyrolysis furnace 1 while receiving heat from the fluidizing medium for pyrolysis. The residue from the raw material, along with a portion of the fluidizing medium, is conveyed to the media regeneration furnace 31 via the media conveying channel 48. The media regeneration furnace 31 is supplied with a fluidizing gas G2 for fluidizing the fluidizing medium.

[0040] The residue of the raw material is combusted while swirling with the fluidized medium in the medium regeneration furnace 31. The combustion of the residue releases heat energy, generating combustion exhaust gas and heating the fluidized medium. A portion of the heated fluidized medium is then conveyed to the pyrolysis furnace 1 via the medium conveying channel 47. The heated fluidized medium provides the heat required for pyrolysis, thus the pyrolysis of the raw material takes place within the pyrolysis furnace 1. The conveying of the fluidized medium via the medium conveying channels 47 and 48 can utilize gravity, conveyors, or pressure conveying by air or inactive gas, but there are no particular limitations as long as the fluidized medium can be conveyed.

[0041] The solid-gas separation device 6 is connected to the pyrolysis furnace 1 via the pyrolysis gas delivery pipeline 8. When the raw material is pyrolyzed, pyrolysis gas is generated. This pyrolysis gas is delivered from the pyrolysis furnace 1 to the solid-gas separation device 6 via the pyrolysis gas delivery pipeline 8. The solid-gas separation device 6 is positioned downstream of the pyrolysis furnace 1 in the direction of pyrolysis gas flow. The structure of the solid-gas separation device 6 is similar to that of the reference device. Figure 1 The solid-gas separation device 6 described in the embodiment is the same. The particle return line 37 extends from the solid-gas separation device 6 to the media regeneration furnace 31. Small-diameter particles captured by the solid-gas separation device 6 are sent to the media regeneration furnace 31 through the particle return line 37.

[0042] The solid-gas separation device 43 is connected to the media regeneration furnace 31 via a combustion exhaust gas delivery pipeline 38. The combustion exhaust gas generated in the media regeneration furnace 31 is transported from the furnace 31 to the solid-gas separation device 43 via the combustion exhaust gas delivery pipeline 38. The solid-gas separation device 43 is positioned downstream of the media regeneration furnace 31 in the direction of combustion exhaust gas flow. The structure of the solid-gas separation device 43 is shown in the reference diagram. Figure 1 The solid-gas separation device 6 in the described embodiment is the same. The particle return line 45 extends from the solid-gas separation device 43 to the pyrolysis furnace 1. Small-diameter particles captured by the solid-gas separation device 43 are sent to the pyrolysis furnace 1 through the particle return line 45.

[0043] The operation of the pyrolysis gasification system in this embodiment is as follows: Raw materials are fed into the pyrolysis furnace 1, where they receive heat from the fluidizing medium and undergo pyrolysis. Small-diameter particles contained in the fluidizing medium, along with the pyrolysis gas generated by the pyrolysis, are sent to the solid-gas separation device 6. The solid-gas separation device 6 captures the small-diameter particles contained in the pyrolysis gas. The captured small-diameter particles are sent to the medium regeneration furnace 31 via the particle return line 37. The small-diameter particles are heated in the medium regeneration furnace 31 due to the combustion of the raw material residue. The heated small-diameter particles are propelled within the medium regeneration furnace 31 by the fluidizing gas G2 that fluidizes the fluidizing medium, and are discharged from the medium regeneration furnace 31 along with the combustion exhaust. The high-temperature small-diameter particles contained in the combustion exhaust are captured by the solid-gas separation device 43 and returned to the pyrolysis furnace 1 via the particle return line 45. The high-temperature small-diameter particles are propelled within the pyrolysis furnace 1 by the fluidizing gas G1 that fluidizes the fluidizing medium, and rapidly reach the free space 3. Therefore, the temperature within free space 3 is maintained at a high level, allowing the pyrolysis reaction to proceed within free space 3. As a result, the yield of the target pyrolysis product can be increased.

[0044] The pyrolysis gasification system of this embodiment also includes: a gas sealing device 51, which prevents backflow of gas from the medium regeneration furnace 31; and a gas sealing device 52, which prevents backflow of gas from the pyrolysis furnace 1. The gas sealing device 51 is installed on the particle return line 37, and the gas sealing device 52 is installed on the particle return line 45. Furthermore, gas sealing devices 53 and 54 are also installed in the medium transport channels 47 and 48. Examples of gas sealing devices 51, 52, 53, and 54 include annular seals, rotary valves, and drip valves, but the gas sealing devices 51, 52, 53, and 54 are not limited to these examples.

[0045] The purpose of providing gas sealing devices 51, 52, 53, and 54 is as follows: The pyrolysis furnace 1 operates in an oxygen-deficient and combustible gas atmosphere for pyrolysis. On the other hand, the media regeneration furnace 31 operates in an oxygen (air) atmosphere to burn the residue remaining after pyrolysis. Therefore, if the gas in the pyrolysis furnace 1 mixes with the gas in the media regeneration furnace 31, safety problems such as fire or explosion may occur. Therefore, by providing gas sealing devices 51, 52, 53, and 54, gas mixing (backflow) is reliably prevented. Furthermore, for media conveying channels 47 and 48, if gas mixing (backflow) can be reliably prevented by the provided fluidized medium conveying means, the provision of gas sealing devices 53 and 54 can be omitted.

[0046] Figure 4 This is a schematic diagram illustrating another embodiment of the pyrolysis gasification system. Structures and operations not specifically described in this embodiment are similar to those described in the reference diagram. Figure 3 The implementation methods described are the same, so repeated descriptions are omitted.

[0047] The pyrolysis gasification system also includes a media settling chamber 55 connecting the pyrolysis furnace 1 and the media regeneration furnace 31. The media settling chamber 55 is located between the pyrolysis furnace 1 and the media regeneration furnace 31. The pyrolysis furnace 1, the media regeneration furnace 31, and the media settling chamber 55 are formed within a fluidized bed furnace 60. That is, the fluidized bed furnace 60 has the pyrolysis furnace 1, the media regeneration furnace 31, and the media settling chamber 55 inside it. A first partition wall 61 is provided between the pyrolysis furnace 1 and the media settling chamber 55, and a second partition wall 62 is provided between the media regeneration furnace 31 and the media settling chamber 55. In this embodiment, the media settling chamber 55 is equipped with a gas-sealing function.

[0048] Figure 4 The medium transport channel 48 is schematically depicted, but it is also located within the fluidized bed furnace 60. Furthermore, in Figure 4 In the diagram, the pyrolysis furnace 1, the media regeneration furnace 31, and the media settling chamber 55 are drawn in a planar manner, but in reality, the pyrolysis furnace 1, the media regeneration furnace 31, and the media settling chamber 55 are three-dimensional. The pyrolysis furnace 1 can also be arranged next to both the media regeneration furnace 31 and the media settling chamber 55. Therefore, the media conveying channel 48 is sometimes also composed of a single opening.

[0049] Fluidization medium used and reference Figure 1The described implementation also includes large-diameter particles and small-diameter particles with different average particle sizes. The small-diameter particles can be latent heat storage microcapsules. The media regeneration furnace 31 is connected to the pyrolysis furnace 1 via a media settling chamber 55 and a media conveying channel 48. The raw material is pyrolyzed while being stirred by the swirling flow of the fluidizing medium within the pyrolysis furnace 1, receiving heat from the fluidizing medium. The residue from the raw material, along with a portion of the fluidizing medium, is conveyed to the media regeneration furnace 31 via the media conveying channel 48. The media regeneration furnace 31 is supplied with a fluidizing gas G2 for fluidizing the fluidizing medium.

[0050] The residue of the raw material is combusted while swirling with the fluidized medium in the medium regeneration furnace 31. The combustion of the residue releases heat energy, generating combustion exhaust gas and heating the fluidized medium. A portion of the heated fluidized medium overflows through the second partition wall 62 and flows into the medium settling chamber 55, where it descends. Subsequently, the fluidized medium is fed to the pyrolysis furnace 1 through the lower opening of the first partition wall 61. The heated fluidized medium provides the heat required for pyrolysis, thus the pyrolysis of the raw material takes place in the pyrolysis furnace 1. The fluidized bed furnace 60, in which the fluidized medium circulates between the pyrolysis furnace 1, the medium regeneration furnace 31, and the medium settling chamber 55, is referred to as an internal circulating fluidized bed gasification system.

[0051] The operation of the pyrolysis gasification system in this embodiment is as follows: Raw materials are fed into the pyrolysis furnace 1 and undergo pyrolysis by receiving heat from the fluidizing medium. Small-diameter particles contained in the fluidizing medium, along with the pyrolysis gas generated by the pyrolysis, are sent to the solid-gas separation device 6. The solid-gas separation device 6 captures the small-diameter particles contained in the pyrolysis gas. The captured small-diameter particles are sent to the medium regeneration furnace 31 through the particle return line 37. The small-diameter particles are heated in the medium regeneration furnace 31 due to the combustion of the raw material residue. The heated small-diameter particles are propelled within the medium regeneration furnace 31 by the fluidizing gas G2 that fluidizes the fluidizing medium, and are discharged from the medium regeneration furnace 31 along with the combustion exhaust. The high-temperature small-diameter particles contained in the combustion exhaust are captured by the solid-gas separation device 43 and returned to the pyrolysis furnace 1 through the particle return line 45. The high-temperature small-diameter particles are propelled within the pyrolysis furnace 1 by the fluidizing gas G1 that fluidizes the fluidizing medium, and rapidly reach the free space 3. Therefore, the temperature within free space 3 is maintained at a high level, allowing the pyrolysis reaction to proceed within free space 3. As a result, the yield of the target pyrolysis product can be increased.

[0052] Figure 5 This is a schematic diagram illustrating another embodiment of the pyrolysis gasification system. Structures and operations not specifically described in this embodiment are similar to those described in the reference diagram. Figure 4 The implementation methods described are the same, so repeated descriptions are omitted.

[0053] The pyrolysis gasification system includes: a particle return line 65 extending from the solid-gas separation unit 6 to the medium settling chamber 55; and a gas sealing device 66 preventing backflow of gas from the medium settling chamber 55. The gas sealing device 66 is installed on the particle return line 65. Examples of the gas sealing device 66 include annular seals, rotary valves, drip valves, etc., but the gas sealing device 66 is not limited to these examples. The purpose and reference of providing the gas sealing device 66 are as follows. Figure 3 The gas sealing devices 51, 52, 53, and 54 in the described embodiments are the same. In this embodiment, no such device is provided. Figure 3 The solid-gas separation device 43, particle return pipelines 37 and 45, and gas sealing devices 51 and 52 are shown. The media settling chamber 55 is equipped with a gas sealing function.

[0054] The operation of the pyrolysis gasification system in this embodiment is as follows: Raw materials are fed into the pyrolysis furnace 1 and undergo pyrolysis by receiving heat from the fluidizing medium. Small-diameter particles contained in the fluidizing medium, along with the pyrolysis gas generated by the pyrolysis, are sent to the solid-gas separation device 6. The solid-gas separation device 6 captures the small-diameter particles contained in the pyrolysis gas. The captured small-diameter particles are sent to the medium settling chamber 55 via the particle return line 65. The small-diameter particles returned to the medium settling chamber 55 are mixed with the high-temperature fluidizing medium from the medium regeneration furnace 31 and heated. The heated small-diameter particles, along with the fluidizing medium, are sent back to the pyrolysis furnace 1. Under the action of the fluidizing gas G1 that fluidizes the fluidizing medium, the small-diameter particles in the fluidizing medium are propelled within the pyrolysis furnace 1 and rapidly reach the free space 3. Therefore, the temperature in the free space 3 is maintained at a high temperature, allowing the pyrolysis reaction to proceed in the free space 3. As a result, the yield of the target pyrolysis product can be improved.

[0055] Figure 6 This is a schematic diagram illustrating another embodiment of the pyrolysis gasification system. Structures and operations not specifically described in this embodiment are similar to those described in the reference diagram. Figure 4 The implementation methods described are the same, so repeated descriptions are omitted.

[0056] The pyrolysis gasification system includes: a particle return line 70 extending from the solid-gas separator 6 via the media regeneration furnace 31 to the pyrolysis furnace 1; and a gas sealing device 71 to prevent backflow of gas from the pyrolysis furnace 1. The gas sealing device 71 is installed on the particle return line 70. The gas sealing device 71 is provided to prevent a decrease in pyrolysis yield and particle dispersion downstream of the solid-gas separator 6.

[0057] The particle return line 70 passes through the interior of the media regeneration furnace 31 and extends to the pyrolysis furnace 1. Since a portion of the particle return line 70 is located inside the media regeneration furnace 31, small-diameter particles captured by the solid-gas separation device 6 are conveyed within the particle return line 70 while being heated by the combustion of the residue in the raw material within the media regeneration furnace 31. In this embodiment, no [further details are needed]. Figure 3 The solid-gas separation device 43, particle return pipelines 37 and 45, and gas sealing devices 51 and 52 are shown. The media settling chamber 55 is equipped with a gas sealing function.

[0058] The operation of the pyrolysis gasification system in this embodiment is as follows: Raw materials are fed into the pyrolysis furnace 1 and undergo pyrolysis by receiving heat from the fluidizing medium. Small-diameter particles contained in the fluidizing medium, along with the pyrolysis gas generated by the pyrolysis, are sent to the solid-gas separation device 6. The solid-gas separation device 6 captures the small-diameter particles contained in the pyrolysis gas. The captured small-diameter particles are conveyed in the particle return line 70 while being heated by combustion in the medium regeneration furnace 31. The heated small-diameter particles are returned to the pyrolysis furnace 1 through the particle return line 70. The high-temperature small-diameter particles are propelled within the pyrolysis furnace 1 by the fluidizing gas G1 that fluidizes the fluidizing medium and rapidly reach the free space 3. Therefore, the temperature in the free space 3 is maintained at a high temperature, allowing the pyrolysis reaction to proceed in the free space 3. As a result, the yield of the target pyrolysis product can be improved.

[0059] Figure 7 This is a schematic diagram illustrating another embodiment of the pyrolysis gasification system. Structures and operations not specifically described in this embodiment are similar to those described in the reference diagram. Figure 1 and Figure 4 The implementation methods described are the same, so repeated descriptions are omitted.

[0060] Pyrolysis Gasification System and Reference Figure 1 The described embodiment similarly includes: a solid-gas separation device 6 that collects small-diameter particles contained in the pyrolysis gas discharged from the pyrolysis furnace 1; a heating device 12 that heats the small-diameter particles collected by the solid-gas separation device 6; a particle return line 15 that returns the small-diameter particles heated by the heating device 12 to the pyrolysis furnace 1; and a gas sealing device 18 installed on the particle return line 15. The structure of the heating device 12, the particle return line 15, and the gas sealing device 18 is consistent with the reference. Figure 1 The implementation method described is the same. In this implementation method, no [specific method] is set. Figure 3 The solid-gas separation device 43, particle return pipelines 37 and 45, and gas sealing devices 51 and 52 are shown. The media settling chamber 55 is equipped with a gas sealing function.

[0061] The operation of the pyrolysis gasification system in this embodiment is as follows: Raw materials are fed into the pyrolysis furnace 1 and undergo pyrolysis by receiving heat from the fluidizing medium. Small-diameter particles contained in the fluidizing medium, along with the pyrolysis gas generated by the pyrolysis, are sent to the solid-gas separation device 6. The solid-gas separation device 6 captures the small-diameter particles contained in the pyrolysis gas. The captured small-diameter particles are heated by the heating device 12. The heated small-diameter particles are returned to the pyrolysis furnace 1 through the particle return line 15. The high-temperature small-diameter particles are propelled within the pyrolysis furnace 1 by the fluidizing gas G1 that fluidizes the fluidizing medium and rapidly reach the free space 3. Therefore, the temperature within the free space 3 is maintained at a high temperature, allowing the pyrolysis reaction to proceed within the free space 3. As a result, the yield of the target pyrolysis product can be improved.

[0062] The above embodiments are described with the aim of enabling those skilled in the art to practice the present invention. Those skilled in the art will naturally be able to derive various modifications of the above embodiments, and the technical concept of the present invention can be applied to other embodiments. Therefore, the present invention is not limited to the above embodiments, but can be interpreted as encompassing the maximum scope derived from the technical concept defined in the claims. Industrial applicability

[0063] This invention relates to a pyrolysis gasification method for pyrolyzing raw materials in a pyrolysis furnace, and particularly to a technique for controlling the temperature inside the pyrolysis furnace. Explanation of reference numerals in the attached figures

[0064] 1...pyrolysis furnace 2... Thick layer 3...Free Space 6...Solid-gas separation device 8...Pyrolysis gas delivery pipeline 12... Heating device 15...Particle Return Pipeline 18...Gas Sealing Device 20...Latent heat storage materials 21...shell 31...Media Regeneration Furnace 37...Particle Return Pipeline 38... Combustion exhaust pipeline 43...Solid-Gas Separation Device 45...Particle return pipeline 47...Media transport channel 48...Media transport channel 51, 52... Gas sealing devices 53, 54... Gas sealing devices 55...Media Settling Chamber 60... Fluidized bed furnace 61...First partition wall 62...Second partition wall 65...Particle return pipeline 66...Gas Sealing Device 70...Particle return pipeline 71...Gas Sealing Device G1, G2... fluidizing gases.

Claims

1. A pyrolysis gasification method, characterized in that, Used for pyrolysis of raw materials The raw material is pyrolyzed in a pyrolysis furnace using the heat of a fluidized medium comprising a mixture of large and small particles with different average particle sizes. The small-diameter particles contained in the pyrolysis gas discharged from the pyrolysis furnace are captured by a solid-gas separation device. The small-diameter particles captured by the solid-gas separation device are heated by a heating device. The small-diameter particles, after being heated by the heating device, are returned to the pyrolysis furnace through the particle return pipeline.

2. The pyrolysis gasification method according to claim 1, characterized in that, The average particle size of the large-diameter particles is in the range of 300 μm to 600 μm. The average particle size of the small-diameter particles is in the range of 20 μm to 40 μm.

3. The pyrolysis gasification method according to claim 1, characterized in that, The large-diameter particles and the small-diameter particles are made of the same material, and the weight ratio of the large-diameter particles to the small-diameter particles is 9:1 to 5:

5.

4. The pyrolysis gasification method according to claim 1, characterized in that, The small-diameter particles are latent heat storage microcapsules.

5. A pyrolysis gasification method, characterized in that, Used for pyrolysis of raw materials The raw material is pyrolyzed in a pyrolysis furnace using the heat of a fluidized medium comprising a mixture of large and small particles with different average particle sizes. While fluidizing the fluidizing medium, the residue of the raw material is burned in the medium regeneration furnace; The small-diameter particles contained in the pyrolysis gas discharged from the pyrolysis furnace are captured by the first solid-gas separation device; The small-diameter particles captured by the first solid-gas separation device are returned to the medium regeneration furnace through the first particle return pipeline; The small-diameter particles contained in the combustion exhaust gas discharged from the medium regeneration furnace are captured by the second solid-gas separation device. The small-diameter particles captured by the second solid-gas separation device are returned to the pyrolysis furnace through the second particle return pipeline.

6. The pyrolysis gasification method according to claim 5, characterized in that, The average particle size of the large-diameter particles is in the range of 300 μm to 600 μm. The average particle size of the small-diameter particles is in the range of 20 μm to 40 μm.

7. The pyrolysis gasification method according to claim 5, characterized in that, The large-diameter particles and the small-diameter particles are made of the same material, and the weight ratio of the large-diameter particles to the small-diameter particles is 9:1 to 5:

5.

8. The pyrolysis gasification method according to claim 5, characterized in that, The small-diameter particles are latent heat storage microcapsules.

9. A pyrolysis gasification method, characterized in that, Used for pyrolysis of raw materials The raw material is pyrolyzed in a pyrolysis furnace using the heat of a fluidized medium comprising a mixture of large and small particles with different average particle sizes. While fluidizing the fluidizing medium, the residue of the raw material is burned in the medium regeneration furnace; The fluidized medium is transported from the medium regeneration furnace to the pyrolysis chamber through the medium settling chamber; The small-diameter particles contained in the pyrolysis gas discharged from the pyrolysis furnace are captured by a solid-gas separation device. The small-diameter particles captured by the solid-gas separation device are returned to the medium settling chamber through the particle return pipeline.

10. The pyrolysis gasification method according to claim 9, characterized in that, The average particle size of the large-diameter particles is in the range of 300 μm to 600 μm. The average particle size of the small-diameter particles is in the range of 20 μm to 40 μm.

11. The pyrolysis gasification method according to claim 9, characterized in that, The large-diameter particles and the small-diameter particles are made of the same material, and the weight ratio of the large-diameter particles to the small-diameter particles is 9:1 to 5:

5.

12. The pyrolysis gasification method according to claim 9, characterized in that, The small-diameter particles are latent heat storage microcapsules.

13. A pyrolysis gasification method, characterized in that, Used for pyrolysis of raw materials The raw material is pyrolyzed in a pyrolysis furnace using the heat of a fluidized medium comprising a mixture of large and small particles with different average particle sizes. The small-diameter particles contained in the pyrolysis gas discharged from the pyrolysis furnace are captured by a solid-gas separation device. The small-diameter particles captured by the solid-gas separation device are returned to the pyrolysis furnace through the particle return pipeline; The particle return pipeline passes through the interior of the media regeneration furnace and extends toward the pyrolysis furnace, and the small-diameter particles in the particle return pipeline are heated by the combustion of the residue of the raw material in the media regeneration furnace.

14. The pyrolysis gasification method according to claim 13, characterized in that, The average particle size of the large-diameter particles is in the range of 300 μm to 600 μm. The average particle size of the small-diameter particles is in the range of 20 μm to 40 μm.

15. The pyrolysis gasification method according to claim 13, characterized in that, The large-diameter particles and the small-diameter particles are made of the same material, and the weight ratio of the large-diameter particles to the small-diameter particles is 9:1 to 5:

5.

16. The pyrolysis gasification method according to claim 13, characterized in that, The small-diameter particles are latent heat storage microcapsules.

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