Raw material processing device and processing method

Abstract

The present invention relates to a technology for treating raw materials such as combustible waste, and in particular to a combustion and pyrolysis / gasification treatment technology that does not release carbon dioxide into the atmosphere. The treatment device comprises: a fluidized bed furnace (1) having a pyrolysis chamber (6) and a combustion chamber (7) separated by a partition wall (10); an electrolysis device (2) that electrolyzes water to generate hydrogen and oxygen; a methanation reactor (3) that generates methane from hydrogen and carbon dioxide discharged from the combustion chamber (7); a first fluidizing gas supply line (11) that supplies a first fluidizing gas into the pyrolysis chamber (6); and a second fluidizing gas supply line (12) that introduces a portion of the carbon dioxide and oxygen into the combustion chamber (7) as a second fluidizing gas.

Description

Technical Field

[0001] The present invention relates to a technology for treating raw materials such as combustible waste, and in particular to a combustion and pyrolysis / gasification treatment technology that does not release carbon dioxide into the atmosphere. Background Art

[0002] Carbon dioxide (CO2) is a cause of global warming, so it is necessary to reduce carbon dioxide emissions. However, since carbon dioxide is inevitably generated when combustibles are burned in various combustion devices such as waste treatment systems, reducing the amount of carbon dioxide released into the atmosphere has become an important issue.

[0003] On the other hand, attempts have also been made to recover carbon dioxide emitted from combustion devices and store it underground. However, in order to recover high-concentration carbon dioxide, it is necessary to further use oxygen to completely burn the combustion exhaust gas containing carbon dioxide emitted from the combustion device, or to separate carbon dioxide from the combustion exhaust gas. Such a processing cycle requires additional equipment and also increases costs.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-165388 Summary of the invention

[0007] Problems to be solved by the invention

[0008] To this end, the present invention provides a treatment device and a treatment method that can theoretically reduce the amount of carbon dioxide released into the atmosphere to zero and contribute to the prevention of global warming.

[0009] Means for solving problems

[0010] In one embodiment, a processing device is provided, which is a raw material processing device, and comprises: a fluidized bed furnace, which has a pyrolysis chamber and a combustion chamber separated by a partition wall; an electrolysis device, which electrolyzes water to generate hydrogen and oxygen; a methanation reactor, which generates methane from the aforementioned hydrogen and carbon dioxide discharged from the aforementioned combustion chamber; a first fluidizing gas supply pipeline, which supplies a first fluidizing gas into the aforementioned pyrolysis chamber; and a second fluidizing gas supply pipeline, which introduces a portion of the aforementioned carbon dioxide and the aforementioned oxygen into the aforementioned combustion chamber as a second fluidizing gas.

[0011] In one embodiment, the electrolysis device is electrically connected to a CO2-free generator.

[0012] In one embodiment, the first fluidizing gas supply line is an oxygen-free gas supply line that supplies an oxygen-free gas as the first fluidizing gas into the pyrolysis chamber.

[0013] In one embodiment, the processing device further includes a hydrogen tank for storing hydrogen generated by the electrolysis device, and the hydrogen tank is arranged between the electrolysis device and the methanation reactor.

[0014] In one embodiment, the processing device further includes an oxygen tank storing oxygen generated by the electrolysis device, and the oxygen tank is disposed between the electrolysis device and the combustion chamber.

[0015] In one embodiment, a method is provided, which is a method for processing raw materials using a fluidized bed furnace having a pyrolysis chamber and a combustion chamber separated by a partition wall, wherein water is electrolyzed to generate hydrogen and oxygen, a first fluidizing gas is supplied to the pyrolysis chamber while a fluidized medium in the combustion chamber is moved to the pyrolysis chamber, the raw material is pyrolyzed in the pyrolysis chamber, a residue of the raw material is burned in the combustion chamber, methane is generated from the hydrogen and carbon dioxide discharged from the combustion chamber, and a portion of the carbon dioxide and the oxygen are supplied to the combustion chamber as a second fluidizing gas.

[0016] In one embodiment, the water is electrolyzed using CO2-free electricity.

[0017] In one embodiment, the first fluidizing gas is an oxygen-free gas.

[0018] Effects of the Invention

[0019] According to the present invention, the carbon dioxide discharged from the combustion chamber reacts with the hydrogen generated by the electrolysis device to generate methane. Therefore, the treatment device and treatment method of the present invention can theoretically reduce the amount of carbon dioxide released into the atmosphere to zero. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] [ Figure 1 ] is a schematic diagram showing an embodiment of a processing device.

[0021] [ Figure 2 ] is a schematic diagram showing another embodiment of the processing device.

[0022] [ Figure 3 ] is a schematic diagram showing another embodiment of the processing device. DETAILED DESCRIPTION

[0023] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0024] Figure 1 The present invention is a schematic diagram showing an embodiment of a processing device for processing raw materials such as combustible waste. Figure 1The processing apparatus shown includes a fluidized bed furnace 1 which is an incinerator for burning raw materials, an electrolysis device 2 which electrolyzes water to generate hydrogen and oxygen, and a methanation reactor 3 which generates methane from carbon dioxide discharged from the fluidized bed furnace 1 and hydrogen generated by the electrolysis device 2 .

[0025] The fluidized bed furnace 1 includes: a pyrolysis chamber 6, which pyrolyzes the raw material to generate pyrolysis products such as hydrocarbons; and a combustion chamber 7, which burns the residue of the raw material obtained by pyrolysis. The pyrolysis chamber 6 and the combustion chamber 7 are formed in one fluidized bed furnace 1. That is, the interior of the fluidized bed furnace 1 is divided into the pyrolysis chamber 6 and the combustion chamber 7 by the partition wall 10. The overall shape of the fluidized bed furnace 1 is not particularly limited, and has, for example, a cylindrical or rectangular shape.

[0026] Fluidizing medium (eg, silica sand) is contained in the pyrolysis chamber 6 and the combustion chamber 7. The pyrolysis chamber 6 and the combustion chamber 7 are connected to a first fluidizing gas supply line 11 and a second fluidizing gas supply line 12, respectively, in order to flow the fluidizing medium.

[0027] The first fluidizing gas supply pipeline 11 is connected to the first wind box 15 located below the pyrolysis chamber 6, and communicates with the pyrolysis chamber 6 through the first wind box 15. The upper wall of the first wind box 15 is composed of a porous plate 15a. The porous plate 15a constitutes the furnace bed of the pyrolysis chamber 6. The first fluidizing gas supply pipeline 11 supplies the first fluidizing gas into the pyrolysis chamber 6 through the first wind box 15, so that the fluidized medium in the pyrolysis chamber 6 flows. The flowing fluidized medium forms a first fluidized bed 18 in the pyrolysis chamber 6.

[0028] The second fluidizing gas supply line 12 is connected to a second wind box 16 located below the combustion chamber 7, and communicates with the combustion chamber 7 through the second wind box 16. The upper wall of the second wind box 16 is composed of a porous plate 16a. The porous plate 16a constitutes the hearth of the combustion chamber 7. The second fluidizing gas supply line 12 supplies part of the carbon dioxide discharged from the combustion chamber 7 and oxygen generated by the electrolysis device 2 as the second fluidizing gas into the combustion chamber 7 through the second wind box 16, so that the fluidized medium in the combustion chamber 7 flows. The flowing fluidized medium forms a second fluidized bed 19 in the combustion chamber 7.

[0029] The treatment device is provided with a combustion exhaust gas delivery pipeline 24 extending from an exhaust gas outlet 22 provided above the combustion chamber 7 to the methanation reactor 3. In addition, the treatment device is provided with a carbon dioxide return pipeline 25 connected to the combustion exhaust gas delivery pipeline 24 and the fluidized bed furnace 1. One end of the carbon dioxide return pipeline 25 is connected to the combustion exhaust gas delivery pipeline 24, and the other end of the carbon dioxide return pipeline 25 is connected to the second wind box 16. A part of the carbon dioxide generated in the combustion chamber 7 is returned to the combustion chamber 7 through the carbon dioxide return pipeline 25, and the remaining carbon dioxide is sent to the methanation reactor 3 through the combustion exhaust gas delivery pipeline 24.

[0030] Oxygen generated by the electrolysis device 2 is delivered to the combustion chamber 7 through the oxygen delivery pipeline 30 and the carbon dioxide return pipeline 25. One end of the oxygen delivery pipeline 30 is connected to the electrolysis device 2, and the other end of the oxygen delivery pipeline 30 is connected to the carbon dioxide return pipeline 25. Oxygen is mixed with carbon dioxide flowing through the carbon dioxide return pipeline 25. The mixture of carbon dioxide and oxygen flowing through the carbon dioxide return pipeline 25 is introduced into the combustion chamber 7 as a second fluidizing gas, so that the fluidizing medium in the combustion chamber 7 flows. In this embodiment, the second fluidizing gas supply pipeline 12 is composed of at least a part of the combustion exhaust gas delivery pipeline 24, the carbon dioxide return pipeline 25, and the oxygen delivery pipeline 30.

[0031] The partition wall 10 extends downward from the upper wall 1a of the fluidized bed furnace 1. The lower end of the partition wall 10 is not connected to the furnace bed, and there is an opening 26 below the partition wall 10. The opening 26 is located at the bottom of the pyrolysis chamber 6 and the combustion chamber 7, and the pyrolysis chamber 6 and the combustion chamber 7 are connected to each other through the opening 26. The opening 26 allows the fluidized medium heated in the combustion chamber 7 to move into the pyrolysis chamber 6. The opening 26 is located below the interface (upper surface) of the first fluidized bed 18 and the second fluidized bed 19 in the pyrolysis chamber 6 and the combustion chamber 7.

[0032] In the combustion chamber 7, a swirling flow of the fluidized medium is formed by the second fluidizing gas formed of carbon dioxide and oxygen. The second fluidized bed 19 is formed by such a swirling flow of the fluidized medium. A part of the fluidized medium forming the swirling flow in the combustion chamber 7 flows into the pyrolysis chamber 6 through the opening 26 and mixes with the fluidized medium forming the first fluidized bed 18. In the pyrolysis chamber 6, a swirling flow of the fluidized medium is formed by the first fluidizing gas. The first fluidized bed 18 is formed by such a swirling flow of the fluidized medium.

[0033] The pyrolysis chamber 6 and the combustion chamber 7 are communicated with each other through a communication channel 35 . Figure 1 The arrow indicating the communication passage 35 is depicted outside the fluidized bed furnace 1, but the communication passage 35 is also located inside the fluidized bed furnace 1. Figure 1 The pyrolysis chamber 6 and the combustion chamber 7 are depicted in a planar manner, but in reality, the pyrolysis chamber 6 and the combustion chamber 7 are three-dimensional, and the pyrolysis chamber 6 can also be arranged beside the combustion chamber 7. Therefore, the communication passage 35 can also be composed of a simple opening.

[0034] The fluidized bed furnace 1 has a raw material supply port 37 for supplying raw materials such as waste and biomass into the pyrolysis chamber 6. The raw materials introduced into the pyrolysis chamber 6 through the raw material supply port 37 are stirred by the swirling flow of the fluidized medium forming the first fluidized bed 18 while receiving heat from the fluidized medium to be pyrolyzed. As a result of the pyrolysis, a part of the components contained in the raw materials forms a generated gas as a pyrolysis product (for example, hydrocarbons CnHm, n and m are integers). The generated gas is discharged from the pyrolysis chamber 6 through the generated gas outlet 41, and the aforementioned generated gas outlet 41 is provided on the upper wall 1a of the fluidized bed furnace 1 forming the pyrolysis chamber 6. The generated gas outlet 41 is connected to the pyrolysis chamber 6.

[0035] A generated gas delivery line 45 is connected to the generated gas outlet 41. The processing device is provided with a cyclone 47 and a scrubber 48 connected to the generated gas delivery line 45. The cyclone 47 and the scrubber 48 are arranged in series along the generated gas delivery line 45. The generated gas discharged from the pyrolysis chamber 6 is sent to the cyclone 47 through the generated gas delivery line 45, and the cyclone 47 is used to remove dust from the generated gas. In addition, the generated gas is sent to the scrubber 48, and the generated gas is washed with water (which may also be water containing an alkaline reagent such as sodium hydroxide) through the scrubber 48. The scrubber 48 may be configured as follows: oil is used instead of water to wash the generated gas; or water and oil are used to wash the generated gas. The generated gas purified in this way can be used as a fuel gas, a chemical raw material, etc. There is also a case where either or both of the cyclone 47 and the scrubber 48 are not provided.

[0036] In the present embodiment, as the first fluidizing gas supplied to the pyrolysis chamber 6, an oxygen-free gas that does not contain oxygen can be used. Therefore, the first fluidizing gas supply line 11 of the present embodiment is an oxygen-free gas supply line. Examples of oxygen-free gases include generated gas discharged from the pyrolysis chamber 6, water vapor, inert gas (e.g., nitrogen), or methane generated in the methanation reactor 3. The oxygen-free gas can be a mixture of at least two of generated gas, water vapor, inert gas, and methane. In the present embodiment, water vapor is used as the first fluidizing gas. As for the first fluidizing gas, it is preferred to use a combination of generated gas discharged from the pyrolysis chamber 6 and methane generated in the methanation reactor 3. As for the first fluidizing gas containing a combination of generated gas and methane, it is a gas with a chemical composition close to that of the generated gas generated by pyrolysis of the raw material, so the purity of the generated gas is improved. In addition, when it is desired to make the generated gas contain a chemical substance containing oxygen atoms, a gasification reaction can be carried out in the pyrolysis chamber 6 by supplying an oxygen-containing gas to the empty tower portion of the pyrolysis chamber 6.

[0037] The residue of the raw material in the pyrolysis chamber 6 moves to the combustion chamber 7 through the connecting passage 35 together with the fluidized medium. The residue of the raw material swirls together with the fluidized medium forming the second fluidized bed 19 while being burned in the presence of oxygen contained in the second fluidized gas. The residue of the raw material generates carbon dioxide and releases heat energy as it burns, heating the fluidized medium forming the second fluidized bed 19. The carbon dioxide and the remaining oxygen are discharged from the combustion chamber 7 through the exhaust gas outlet 22 as combustion exhaust gas. The exhaust gas outlet 22 is provided on the upper wall 1a of the fluidized bed furnace 1 forming the combustion chamber 7. The exhaust gas outlet 22 is connected to the combustion chamber 7.

[0038] A portion of the heated fluidized medium flows into the pyrolysis chamber 6 through the opening 26. The heated fluidized medium provides the heat required for pyrolysis of the raw material, thereby pyrolysis of the raw material is performed in the pyrolysis chamber 6. In addition, the fluidized medium moves to the combustion chamber 7 through the connecting passage 35 together with the residue of the raw material. In this way, the fluidized medium circulates between the pyrolysis chamber 6 and the combustion chamber 7.

[0039] The raw materials fed into the pyrolysis chamber 6 are combustible materials containing carbon (C), such as waste plastics, wood, and biomass. The raw materials are pyrolyzed in the pyrolysis chamber 6 without being burned. Since the raw materials contain carbon, carbide (char) is easily generated in the pyrolysis chamber 6. The carbide (char) cannot be taken out of the pyrolysis chamber 6 as generated gas, but on the other hand, it retains a high calorific value. A portion of the raw material is discharged from the pyrolysis chamber 6 as generated gas, and the residue of the raw material is sent to the combustion chamber 7 as carbide (char). The carbide (char) has a high calorific value. Therefore, when the carbide (char) burns in the combustion chamber 7, it can generate high thermal energy and heat the fluidized medium to a high temperature. A portion of the heated fluidized medium moves from the combustion chamber 7 to the pyrolysis chamber 6 to pyrolyze the raw material.

[0040] An incombustible matter discharge port 50 is provided between the first wind box 15 and the second wind box 16. Relatively large incombustible matter contained in the raw material is discharged from the incombustible matter discharge port 50.

[0041] The residue of the raw material is burned in the combustion chamber 7 to generate carbon dioxide. The carbon dioxide is discharged from the combustion chamber 7 through the exhaust gas outlet 22 and is transported to the methanation reactor 3 through the combustion exhaust gas transport pipeline 24. The methanation reactor 3 has a methanation catalyst (not shown) inside it, which reacts carbon dioxide with hydrogen to generate methane and water (H2O). In this way, the carbon dioxide flowing into the methanation reactor 3 is converted into methane and water, so that the carbon dioxide is not released into the atmosphere. The generated methane is transported through the methane transport pipeline 53, and the generated water is discharged from the methanation reactor 3 through the drain pipe 54.

[0042] The treatment device includes a boiler 55, a cooling tower 56, a dust collector 57, and a scrubber 58 connected to the combustion exhaust gas conveying pipeline 24. The boiler 55, the cooling tower 56, the dust collector 57, and the scrubber 58 are arranged in series along the combustion exhaust gas conveying pipeline 24. The connection point between the carbon dioxide reflux pipeline 25 and the combustion exhaust gas conveying pipeline 24 is located on the downstream side of the dust collector 57.

[0043] The combustion exhaust gas discharged from the combustion chamber 7 is sent to the boiler 55 through the combustion exhaust gas delivery pipeline 24, and waste heat is recovered by the boiler 55. The combustion exhaust gas is sent to the desuperheater 56 through the combustion exhaust gas delivery pipeline 24, and the combustion exhaust gas is cooled by the desuperheater 56. The desuperheater 56 is an example of a cooler for cooling the combustion exhaust gas.

[0044] The combustion exhaust gas is further sent to the dust collecting device 57 through the combustion exhaust gas conveying pipeline 24, and the dust collecting device 57 is used to remove dust such as fly ash from the combustion exhaust gas. As the dust collecting device 57, for example, a bag filter can be used. In addition, the combustion exhaust gas is sent to the scrubber 58 through the combustion exhaust gas conveying pipeline 24, and the combustion exhaust gas is washed with water (which may also be water containing an alkaline reagent such as sodium hydroxide) through the scrubber 58. The combustion exhaust gas purified in this way is sent to the methanation reactor 3. There is also a case where at least one of the boiler 55, the cooling tower 56, the dust collecting device 57, and the scrubber 58 is not provided. For example, when heat recovery is not performed, the boiler 55 is not provided.

[0045] The electrolysis device 2 is a device that electrolyzes water into hydrogen and oxygen. The electrolysis device 2 is connected to a water supply line 60, and water (H2O) is supplied to the electrolysis device 2 through the water supply line 60. The electrolysis device 2 is also electrically connected to a CO2-free generator 62. The CO2-free generator 62 is a generator driven by renewable energy and generates electricity without producing carbon dioxide. Examples of renewable energy include sunlight, wind power, water power, geothermal energy, solar energy, biomass (organic matter derived from plants and animals), etc. In this embodiment, the CO2-free electricity generated by such a CO2-free generator 62 is supplied to the electrolysis device 2. In order to absorb the fluctuation of the power generation of the CO2-free generator 62, the CO2-free electricity generated by the CO2-free generator 62 can be temporarily stored in a battery (not shown), and the CO2-free electricity is supplied from the battery to the electrolysis device 2.

[0046] The electrolyzer 2 uses CO2-free electricity to electrolyze water to generate hydrogen and oxygen. Hydrogen is transported to the methanation reactor 3 through the hydrogen delivery pipeline 61, and oxygen is supplied to the combustion chamber 7 through the oxygen delivery pipeline 30 and the carbon dioxide return pipeline 25. The hydrogen delivery pipeline 61 extends from the electrolyzer 2 to the methanation reactor 3, and the oxygen delivery pipeline 30 extends from the electrolyzer 2 to the carbon dioxide return pipeline 25. In one embodiment, the oxygen delivery pipeline 30 can also extend from the electrolyzer 2 to the second wind box 16.

[0047] The processing device includes: a hydrogen tank 65 connected to the hydrogen delivery pipeline 61; a hydrogen flow control valve 66 installed on the hydrogen delivery pipeline 61; an oxygen tank 70 connected to the oxygen delivery pipeline 30; and an oxygen flow control valve 71 installed on the oxygen delivery pipeline 30. The hydrogen tank 65 is located between the electrolysis device 2 and the methanation reactor 3, and the oxygen tank 70 is located between the electrolysis device 2 and the combustion chamber 7.

[0048] The hydrogen generated by the electrolysis device 2 is temporarily stored in the hydrogen storage tank 65 through the hydrogen delivery pipeline 61. The hydrogen flow control valve 66 is located between the hydrogen storage tank 65 and the methanation reactor 3. When the hydrogen flow control valve 66 is opened, the hydrogen in the hydrogen storage tank 65 is delivered to the methanation reactor 3 through the hydrogen delivery pipeline 61 and the hydrogen flow control valve 66. Carbon dioxide and hydrogen react in the methanation reactor 3 and are converted into methane and water (H2O).

[0049] The amount of hydrogen to be delivered to the methanation reactor 3 is the amount of methane generated by the reaction of all carbon dioxide and all hydrogen in the methanation reactor 3. Therefore, in order to deliver hydrogen to the methanation reactor 3 at an appropriate flow rate, the processing device includes: a carbon dioxide measuring device 75, which measures the flow rate of carbon dioxide flowing into the methanation reactor 3; and a control unit 80, which adjusts the opening of the hydrogen flow control valve 66 based on the measured value of the carbon dioxide flow rate. The carbon dioxide measuring device 75 is installed on the combustion exhaust gas delivery pipeline 24 at the nearest upstream position of the methanation reactor 3. The carbon dioxide measuring device 75 has a structure that combines a flow meter and a concentration meter. That is, the carbon dioxide measuring device 75 is configured as follows: the flow rate of the combustion exhaust gas flowing through the combustion exhaust gas delivery pipeline 24 is measured, and the concentration of carbon dioxide in the combustion exhaust gas is further measured, and the carbon dioxide flow rate is calculated from the flow rate of the combustion exhaust gas and the concentration of carbon dioxide. The carbon dioxide measuring device 75 is electrically connected to the control unit 80, and the measured value of the carbon dioxide flow rate is sent to the control unit 80.

[0050] The control unit 80 is configured as follows: based on the carbon dioxide flow rate flowing into the methanation reactor 3 (i.e., the measured value of the carbon dioxide flow rate sent from the carbon dioxide measuring device 75), the opening of the hydrogen flow control valve 66 is adjusted to control the flow rate of hydrogen delivered to the methanation reactor 3. More specifically, when the carbon dioxide flow rate increases, the control unit 80 operates the hydrogen flow control valve 66 to increase the flow rate of hydrogen, and when the carbon dioxide flow rate decreases, the control unit 80 operates the hydrogen flow control valve 66 to reduce the flow rate of hydrogen. Through such control, all the carbon dioxide contained in the combustion exhaust gas can react with hydrogen to generate methane. As a result, the carbon dioxide released outside the treatment device is theoretically 0. Methane can be used as a fuel gas such as city gas.

[0051] The control unit 80 is composed of at least one computer. The control unit 80 includes: a storage device 80a, which stores a program; and a computing device 80b, which performs operations according to the commands contained in the program. The storage device 80a includes a main storage device such as a RAM and an auxiliary storage device such as a hard disk drive (HDD) and a solid state drive (SSD). Examples of the computing device 80b include a CPU (central processing unit) and a GPU (graphics processing unit). However, the specific configuration of the control unit 80 is not limited to this embodiment.

[0052] The oxygen generated by the electrolysis device 2 is temporarily stored in the oxygen storage tank 70 through the oxygen delivery line 30. The oxygen flow control valve 71 is located between the oxygen storage tank 70 and the carbon dioxide return line 25. When the oxygen flow control valve 71 is opened, the oxygen in the oxygen storage tank 70 is delivered to the combustion chamber 7 through the oxygen delivery line 30, the oxygen flow control valve 71, and the carbon dioxide return line 25. The oxygen is consumed in the combustion of the residue of the raw material in the combustion chamber 7.

[0053] The processing device includes a thermometer 86 disposed in the combustion chamber 7. In this embodiment, one thermometer 86 is disposed, but a plurality of thermometers 86 arranged in the longitudinal direction may be provided. The thermometer 86 is electrically connected to the control unit 80, and the measured value of the temperature in the combustion chamber 7 is sent to the control unit 80.

[0054] The control unit 80 is configured to adjust the opening of the oxygen flow control valve 71 based on the temperature in the combustion chamber 7 (i.e., the measured value of the temperature in the combustion chamber 7 sent from the thermometer 86). More specifically, the control unit 80 is configured to adjust the opening of the oxygen flow control valve 71 (i.e., the flow rate of oxygen supplied to the combustion chamber 7) so that the temperature in the combustion chamber 7 is maintained within a predetermined range. In one embodiment, the control unit 80 may also be configured to adjust the opening of the oxygen flow control valve 71 based on the oxygen concentration at the exhaust gas outlet 22 of the combustion chamber 7 (i.e., the measured value of the oxygen concentration at the exhaust gas outlet 22 sent from the oxygen concentration measuring device 87). More specifically, the control unit 80 is configured to adjust the opening of the oxygen flow control valve 71 (i.e., the flow rate of oxygen supplied to the combustion chamber 7) so that the oxygen concentration at the exhaust gas outlet 22 of the combustion chamber 7 is maintained within a predetermined range.

[0055] As described above, a portion of the carbon dioxide discharged from the combustion chamber 7 is mixed with the oxygen generated by the electrolysis device 2 and refluxed to the combustion chamber 7. Oxygen acts as an oxidant that oxidizes the carbon (C) contained in the residue of the raw material in the combustion chamber 7. The amount of oxygen (O2) in the combustion chamber 7 is slightly larger than the amount of carbon (C) contained in the residue of the raw material in the combustion chamber 7. Such an amount of oxygen greater than the theoretically optimal amount can absorb fluctuations in the amount of carbon in the combustion chamber 7 and can prevent the generation of carbon monoxide. The carbon in the residue of the raw material reacts with oxygen to generate carbon dioxide. Carbon dioxide forms combustion exhaust gas together with the residual oxygen that is not consumed in the reaction with carbon, and the combustion exhaust gas is discharged from the combustion chamber 7 through the exhaust gas outlet 22.

[0056] The methanogenic reaction is represented by the following formula (1), and the electrolytic reaction of water is represented by the following formula (2).

[0057] CO2+4H2→CH4+2H2O (1)

[0058] 2H2O→2H2+O2 (2)

[0059] From the above formula (1), it can be seen that 4 equivalents of H2 are required to convert 1 equivalent of CO2 into CH4. According to the above formula (2), 2 equivalents of O2 are generated when 4 equivalents of H2 are obtained in the electrolysis of water.

[0060] In the combustion chamber 7 of the fluidized bed furnace 1, 1 equivalent of O2 is required to burn 1 equivalent of carbon (C). Generally, in the combustion process of waste, since the ratio of oxygen to carbon is about 1.2 to 1.3, 0.7 to 0.8 equivalents of O2 remain. The remaining O2 can be sold as oxygen, or in the gasification and melting furnace equipment installed in conjunction, it can be used as gas for the molten oxygen burner.

[0061] In the present embodiment, air is not used as the second fluidizing gas for flowing the fluidizing medium of the combustion chamber 7. Therefore, a combustion exhaust gas containing no nitrogen and containing a high concentration of carbon dioxide can be obtained. In one example, the concentration of carbon dioxide in the combustion exhaust gas discharged from the combustion chamber 7 is 95% or more. The remaining components in the combustion exhaust gas are essentially oxygen. Thus, according to the present embodiment, a combustion exhaust gas rich in CO2 can be obtained. A portion of the CO2-rich combustion exhaust gas is refluxed to the combustion chamber 7 as the second fluidizing gas, and the rest is sent to the methanation reactor 3.

[0062] As described above, the fluidized bed furnace 1 includes two processing chambers, namely, the pyrolysis chamber 6 and the combustion chamber 7. The raw material is not burned in the pyrolysis chamber 6, but is heated by the high-temperature fluidized medium to be pyrolyzed. As a result, a generated gas such as high-calorie hydrocarbons is generated. Since the generated gas does not contain carbon dioxide, the generated gas can be obtained at a high yield. The generated gas discharged from the pyrolysis chamber 6 can be recovered and used as a chemical material.

[0063] The components that are not easily pyrolyzed are sent to the combustion chamber 7 as the residue of the raw material. The residue of the raw material is burned in the presence of oxygen contained in the second fluidizing gas to generate carbon dioxide. In this way, since the fluidized bed furnace 1 having two processing chambers, the pyrolysis chamber 6 and the combustion chamber 7, does not need to separate carbon dioxide from the generated gas, the processing device does not need an instrument for separating carbon dioxide, and the processing device as a whole can be made compact.

[0064] A large amount of carbon contained in the raw material is separated as a generated gas in the pyrolysis chamber 6. Therefore, the amount of carbon dioxide generated from the combustion chamber 7 is small compared to the case where all the carbon in the raw material is burned in the combustion chamber 7. Therefore, the amount of carbon dioxide to be reacted with hydrogen in the methanation reactor 3 is small, and as a result, the methanation reactor 3 can be made compact.

[0065] In recent years, the cost of generating renewable electricity has dropped dramatically, and it is expected that in the near future, there will be no need to consume fossil fuels to generate electricity. However, as materials to support social life, carbon-containing materials such as wood and plastic will be needed in the future, and materials with reduced quality must be treated as waste. The processing device of this embodiment can also suppress CO2 emissions in the process of treating biomass and combustible waste (it can convert the CO2-rich combustion exhaust gas obtained from the combustion chamber 7 into methane for chemical circulation).

[0066] Figure 2 Schematic diagram showing another embodiment of the processing device. The structure and operation of this embodiment not specifically described are the same as those of the reference Figure 1 The embodiments described are the same, so the repeated description is omitted. Figure 2 As shown, the processing device includes a generated gas return line 91 extending from the generated gas delivery line 45 to the first fluidizing gas supply line 11. At least a portion of the generated gas flowing through the generated gas delivery line 45 is supplied to the first fluidizing gas supply line 11 through the generated gas return line 91. In this embodiment, the generated gas discharged from the pyrolysis chamber 6 can be used as at least a portion of the first fluidizing gas as an oxygen-free body.

[0067] Figure 3 Schematic diagram showing another embodiment of the processing device. Figure 1The embodiments described are the same, so the repeated description is omitted. Figure 3 As shown, the processing device is provided with a methane reflux line 92 extending from the methane delivery line 53 to the first fluidizing gas supply line 11. At least a portion of the methane flowing through the methane delivery line 53 is supplied to the first fluidizing gas supply line 11 through the methane reflux line 92. In this embodiment, the methane discharged from the methanation reactor 3 can be used as at least a portion of the first fluidizing gas as an oxygen-free gas.

[0068] The technology of the present invention described above is not only applicable to a fluidized bed furnace having a pyrolysis chamber and a combustion chamber inside, but also applicable to an incineration-type fluidized bed furnace having a combustion chamber but not having a pyrolysis chamber inside. When the present invention is applied to the incineration type, the flow of the combustion exhaust gas is in the order of fluidized bed furnace, boiler, cooling tower, dust collector, and induced draft fan. Usually, since all the combustible components (hydrogen, oxygen, nitrogen, sulfur, chlorine, etc.) in the raw materials are burned in the air, the combustion exhaust gas contains N2 (nitrogen), CO2, H2O, sulfur oxides, nitrogen oxides, hydrogen chloride, etc. In order to recover only CO2 from the combustion exhaust gas, a CO2 recovery device (amine absorption method, CO2 separation membrane method) is set.

[0069] The above embodiments are described for the purpose of enabling a person having common knowledge in the technical field to which the present invention belongs to implement the present invention. Various modifications of the above embodiments are obvious to those skilled in the art, and the technical concept of the present invention may also be applied to other embodiments. Therefore, the present invention is not limited to the described embodiments, and may be interpreted in the broadest scope according to the technical concept defined by the claims.

[0070] Industrial Applicability

[0071] The present invention can be used in technologies for treating raw materials such as combustible wastes, and can be used in particular in combustion and pyrolysis / gasification technologies that do not release carbon dioxide into the atmosphere.

[0072] Description of Reference Numerals

[0073] 1 Fluidized bed furnace

[0074] 2 Electrolysis device

[0075] 3 Methanation reactor

[0076] 6 Pyrolysis Chamber

[0077] 7 Combustion Chamber

[0078] 10. Partition wall

[0079] 11. First fluidizing gas supply line

[0080] 12 Second fluidizing gas supply line

[0081] 15 First Bellows

[0082] 16 Second bellows

[0083] 18. First fluidized bed

[0084] 19 Second fluidized bed

[0085] 22 Exhaust gas outlet

[0086] 24 Combustion waste gas pipeline

[0087] 25 Carbon dioxide return line

[0088] 30 Oxygen delivery line

[0089] 35 Connecting Channels

[0090] 37 Raw material supply port

[0091] 41 Generated gas outlet

[0092] 45 Generate gas pipeline

[0093] 47 Cyclone

[0094] 48 Scrubber

[0095] 50 Non-combustible material discharge port

[0096] 53 Methane pipeline

[0097] 54 Drain pipe

[0098] 55 Boiler

[0099] 56 Cooling Tower

[0100] 57 Dust collection device

[0101] 58 Scrubber

[0102] 60 Water supply line

[0103] 61 Hydrogen pipeline

[0104] 62 CO2-free generators

[0105] 65 Hydrogen Storage Tank

[0106] 66 Hydrogen flow control valve

[0107] 70 Oxygen Tank

[0108] 71 Oxygen flow control valve

[0109] 75 Carbon dioxide meter

[0110] 80 Control Department

[0111] 86 Thermometer

[0112] 87 Oxygen concentration measuring device

[0113] 91 Generated gas reflux pipeline

[0114] 92 Methane reflux line

Claims

1. A processing device, which is a raw material processing device, which has: A fluidized bed furnace having a pyrolysis chamber and a combustion chamber separated by a partition wall; an electrolysis device that electrolyzes water to produce hydrogen and oxygen; a methanation reactor that generates methane from the hydrogen and carbon dioxide exhausted from the combustion chamber; a first fluidizing gas supply line, which supplies a first fluidizing gas into the pyrolysis chamber; a second fluidizing gas supply line that introduces a portion of the carbon dioxide and the oxygen as a second fluidizing gas into the combustion chamber; a hydrogen storage tank for containing hydrogen generated by the electrolysis device; a hydrogen flow control valve for adjusting the flow rate of the hydrogen delivered from the hydrogen storage tank to the methanation reactor; and a control unit that adjusts the opening of the hydrogen flow control valve based on the flow rate of the carbon dioxide flowing into the methanation reactor, Wherein, the hydrogen storage tank and the hydrogen flow control valve are arranged between the electrolysis device and the methanation reactor.

2. The processing device according to claim 1, wherein: The electrolysis device is electrically connected to a CO2-free generator.

3. The processing device according to claim 1 or 2, wherein: The first fluidizing gas supply line is an oxygen-free gas supply line that supplies oxygen-free gas as the first fluidizing gas into the pyrolysis chamber.

4. The processing device according to claim 1 or 2, wherein: The processing device further includes an oxygen storage tank for storing oxygen generated by the electrolysis device. The oxygen storage tank is arranged between the electrolysis device and the combustion chamber.

5. A method for treating a raw material using a fluidized bed furnace having a pyrolysis chamber and a combustion chamber separated by a partition wall, wherein: Electrolyze water to generate hydrogen and oxygen using an electrolysis device. while moving the fluidized medium in the combustion chamber to the pyrolysis chamber, supplying a first fluidizing gas to the pyrolysis chamber, Pyrolyzing the raw material in the pyrolysis chamber, Burning the residue of the raw material in the combustion chamber, generating methane from the hydrogen and the carbon dioxide exhausted from the combustion chamber using a methanation reactor, supplying a portion of the carbon dioxide and the oxygen as a second fluidizing gas to the combustion chamber, The hydrogen generated by electrolysis is stored in a hydrogen storage tank, The flow rate of the hydrogen delivered from the hydrogen storage tank to the methanation reactor is adjusted by a hydrogen flow control valve. adjusting the opening of the hydrogen flow control valve based on the flow rate of the carbon dioxide flowing into the methanation reactor, Wherein, the hydrogen storage tank and the hydrogen flow control valve are arranged between the electrolysis device and the methanation reactor.

6. The method of claim 5, wherein: The electrolysis of the water is performed using CO2-free electricity.

7. The method according to claim 5 or 6, wherein: The first fluidizing gas is an oxygen-free gas.

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