Sintered compact production apparatus and sintered compact production method

Abstract

To provide a sintered compact production apparatus which can reduce the cooling power of a microwave oscillator and further can reduce the heating energy of an object to be heated caused by microwaves.SOLUTION: A sintered compact production apparatus 1 provided with a microwave heating device 2 having a microwave oscillator 21 which oscillates microwaves, a wave guide 22 which is connected to the microwave oscillator 21 and a microwave heating furnace 23 where the microwaves are propagated via the wave guide 22, and is configured to heat an object 5 to be heated in the microwave heating furnace 23 with the microwaves, comprises: an air cooling type cooling device 4 which feeds air to the microwave oscillator 21 and cools the same; and a preheater 3 which preheats the object 5 to be heated with the air which has fed from the air cooling type cooling device 4 to the microwave oscillator 21 and has recovered heat generated in the microwave oscillator 21.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a sintered body manufacturing apparatus equipped with a microwave heating device, and more particularly to a sintered body manufacturing apparatus for manufacturing a carbon dioxide adsorption sintered body using a mixture of coal ash and a Ca source such as waste concrete. [Background technology]

[0002] The present applicant has been researching and developing a technology for producing a carbon dioxide-adsorbed sintered body by irradiating microwaves onto a mixture of coal ash (fly ash) discharged from coal-fired power plants and waste concrete (a calcium source) generated during the production and recycling of utility poles, and then adsorbing carbon dioxide as calcium carbonate during a heating process using microwaves and a cooling process for cooling the sintered body (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6833123 Summary of the Invention [Problem to be solved by the invention]

[0004] As shown in Fig. 3, the microwave heating device 100 includes a microwave oscillator 101 that generates microwaves and a waveguide 102 connected to the microwave oscillator 101. The microwaves are propagated to a microwave heating furnace 103 via the waveguide 102, thereby heating an object to be heated that is placed in the microwave heating furnace. During this process, the magnetron that constitutes the microwave oscillator 101 becomes hot during oscillation, causing the output to become unstable, and therefore needs to be cooled to avoid this. Therefore, in the past, a water-cooling type cooling device 104 was installed around the microwave oscillator, which cools the microwaves by circulating water using a pump or the like.

[0005] However, the water-cooled cooling device 104 requires a large amount of power and energy equivalent to or greater than the heating energy of the microwaves. Therefore, in addition to the heating energy of the microwaves, a large amount of energy is consumed to cool the microwave oscillator, and some kind of improvement is required.

[0006] The present invention has been made in consideration of the above circumstances, and its main object is to provide a sintered body manufacturing apparatus and a sintered body manufacturing method that can reduce the cooling power of a microwave oscillator and also reduce the heating energy of an object to be heated by microwaves. [Means for solving the problem]

[0007] In order to achieve the above object, the sintered body manufacturing apparatus according to the present invention comprises: a microwave oscillator that generates microwaves; a waveguide connected to the microwave oscillator; a microwave heating furnace through which the microwave is propagated via the waveguide, A sintered body manufacturing apparatus including a microwave heating device that heats an object to be heated in the microwave heating furnace with the microwaves, an air-cooling type cooling device that supplies cooling air to the microwave oscillator; a preheater that preheats the object to be heated with air that is supplied from the air-cooling device to the microwave oscillator and recovers heat generated by the microwave oscillator; It is characterized by the provision of the following.

[0008] Therefore, since an air-cooled cooling device is used to cool the microwave oscillator, it is possible to reduce the power required compared to a water-cooled cooling device.In addition, since the object to be heated is preheated using air that is supplied from the air-cooled cooling device to the microwave oscillator and has recovered the heat generated by the microwave oscillator, it is possible to reduce the heating energy by the amount that the object to be heated is preheated when microwaves are irradiated to heat the object to be heated.

[0009] In particular, the above-described configuration is useful from the viewpoint of reducing energy consumption when a mixture of coal ash (e.g., fly ash) and a Ca source (e.g., waste concrete powder) is used as the heated material, and the mixture preheated in a preheater is irradiated with microwaves in a carbon dioxide atmosphere in a microwave heating furnace to produce a carbon dioxide adsorbed sintered body.

[0010] The object to be heated may be placed in a ceramic container and passed through a preheater on a roller conveyor before being introduced into the microwave heating furnace. Furthermore, in order to improve the temperature rise characteristics by microwaves (to produce a sintered body in a short time), a Na source may be further added to the mixture, and in order to increase the CO absorption amount of the sintered body, water may be further added to the mixture. [Effects of the Invention]

[0011] As described above, according to the present invention, the object to be heated is preheated by air that is supplied from an air-cooled cooling device to a microwave oscillator and that recovers the heat generated by the microwave oscillator. This makes it possible to reduce the cooling power compared to cooling using a water-cooled cooling device, and also makes it possible to reduce heating energy by the amount that is preheated when the object to be heated is heated by irradiating microwaves. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a diagram showing the overall configuration of a sintered body manufacturing apparatus; [Figure 2] 1 is a flowchart showing a process of forming a sintered body by irradiating a mixture of coal ash and a Ca source with microwaves. [Figure 3] FIG. 10 is a diagram showing an example of a cooling device for a microwave oscillator of a conventional microwave heating device. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0014] 1 shows a schematic configuration of a sintered body manufacturing apparatus 1. This sintered body manufacturing apparatus 1 has a microwave heating device 2 and a preheater 3.

[0015] The microwave heating device 2 comprises a microwave oscillator 21 that generates microwaves, a waveguide 22 to which the microwave oscillator 21 is connected at one end, and a microwave heating furnace 23 connected to the other end of the waveguide 22, and is configured to heat an object 5 to be heated placed in the microwave heating furnace by microwaves propagated from the microwave oscillator 21 to the microwave heating furnace 23 via the waveguide 22.

[0016] The preheater 3 is provided adjacent to the microwave heating furnace 23 of the microwave heating device 2. The microwave heating furnace 23 and preheater 3 are provided so as to straddle the roller conveyor 6, allowing the object to be heated 5 placed in a container 7 moving on the roller conveyor 6 to pass through the inside of the preheater 3 and the microwave heating furnace 23. Here, the preheater 3 is provided upstream of the microwave heating furnace 23 with respect to the moving direction of the roller conveyor 6, and the object to be heated 5 is introduced into the microwave heating furnace 23 after passing through the preheater 3.

[0017] The object 5 to be heated introduced into the preheater 3 or the object 5 to be heated introduced into the microwave heating furnace 23 may be moved without remaining in the preheater 3 or the microwave heating furnace 23, or may be moved after being retained in the preheater 3 or the microwave heating furnace 23 for a predetermined time, with the retention time being adjusted appropriately depending on the required preheating time or microwave irradiation time.

[0018] Here, the object to be heated 5 is a mixture of coal ash and a Ca source.

[0019] The coal ash may be clinker ash, cinder ash, or fly ash, as long as it is ash produced by burning pulverized coal in a boiler. Here, we will show the case where fly ash, which is produced in the largest quantity and is collected by an electrostatic precipitator at the boiler outlet, is used.

[0020] As the calcium source, powders rich in calcium such as concrete waste (concrete sludge, waste concrete generated during the manufacturing and recycling of utility poles) and steel slag are selected. Here, we show the case where waste concrete powder is used as the calcium source.

[0021] However, the microwave oscillator 21 starts to generate heat as soon as it starts oscillating and heating, but the magnetron that constitutes the microwave oscillator 21 is sensitive to heat, and if the temperature rises during oscillation, the output becomes unstable, so to avoid this, it is necessary to cool the microwave oscillator 21. Therefore, an air-cooling type cooling device 4 is used to cool the microwave oscillator. This air-cooled cooling device 4 is configured, for example, by connecting an inlet duct 41 to an oscillator housing case 21a that houses a microwave oscillator 21, and providing a blower 42 on the upstream side of this inlet duct 41 that draws in outside air and blows it into the inlet duct.

[0022] Moreover, one end of a relay duct 51 is connected to the oscillator housing case 21a. The other end of this relay duct 51 is connected to the preheater 3, and the inside of the oscillator housing case 21a and the inside of the preheater 3 are in communication with each other via the relay duct 51. Furthermore, an exhaust duct 52 leading to an exhaust gas treatment device (not shown) is connected to the preheater 3.

[0023] Therefore, the air introduced into the oscillator housing case 21a from the blower 42 through the inlet duct 41 recovers the heat generated by the microwave oscillator 21 as it passes around the microwave oscillator 21 inside the oscillator housing case 21a, and is then introduced into the preheater 3 through the relay duct 51. The air introduced into the preheater 3 has been warmed by recovering the heat generated by the microwave oscillator 21, so it preheats the object 5 to be heated inside the preheater 3 and is then discharged to the exhaust gas treatment device through the exhaust duct 52.

[0024] The material to be heated (mixture) 5 is placed in a container 7 that is compatible with microwave heating, such as a ceramic container, and moves on the roller conveyor 6. A mechanism for preventing the material to be heated (mixture) 5 from scattering due to the cooling air (air that has recovered the heat generated by the microwave oscillator 21) circulating inside the preheater 3 may be provided in the preheater 3 or the container 7. The preheated object 5 is then sent by roller conveyor 6 to the adjacent microwave heating furnace 23, where it is heated by being irradiated with microwaves in a carbon dioxide atmosphere. In this example, the object is sintered by being held at a temperature equal to or higher than the sintering temperature for a predetermined time.

[0025] Therefore, in the process of producing a carbon dioxide adsorption sintered body using the above-mentioned sintered body production apparatus, as shown in FIG. 2, first, a mixture (object to be heated 5) is formed by mixing fly ash (coal ash) with waste concrete (Ca source) (step S01). At this time, a Na source (sodium hydroxide or sodium chloride) may be added as a sintering aid to enhance the temperature rise characteristics by microwaves, if necessary, and water may be added to increase the amount of CO2 absorbed by the sintered body.

[0026] Thereafter, the mixture (object 5 to be heated) is moved on roller conveyor 6 and introduced into preheater 3, where the mixture (object 5 to be heated) is preheated with cooling air that has been warmed by recovering the heat from microwave oscillator 21 (step S02).

[0027] Thereafter, the mixture (object 5 to be heated) is moved to a microwave heating furnace 23, and microwaves (e.g., 2.45 GHz ± 0.5 GHz) are irradiated in a carbon dioxide atmosphere to raise the temperature of the mixture (object 5 to be heated) to a sintering temperature or higher (e.g., 1000°C), and this state is maintained for a predetermined time (step S03). Thereafter, the sintered body (sintered mixture) is moved on the roller conveyor 6 to be taken out of the microwave heating furnace 23, cooled, and removed, thereby forming a carbon dioxide adsorbing sintered body (step S04).

[0028] Therefore, according to the above-described sintered body manufacturing apparatus 1, an air-cooling method is adopted as the cooling method for the microwave oscillator 21, and therefore the microwave oscillator 21 can be cooled with just the blower 42 and the inlet duct 41, which simplifies the cooling device and also makes it possible to reduce the cooling power compared to the water-cooling method. Furthermore, the object to be heated is preheated in the preheater using air that recovers the heat generated by the microwave oscillator, so when the object to be heated is heated by irradiating microwaves, it is possible to reduce the heating energy by the amount preheated in the preheater.

[0029] In the above-described configuration, an example is shown in which only the heat generated by the microwave oscillator is used to preheat the object to be heated. However, if the temperature of the exhaust gas supplied to the microwave heating furnace is high, for example, a portion of the exhaust gas that has passed through the microwave heating furnace 23 may be guided to the preheater 3 via the bypass duct 53, and then discharged from the exhaust duct 52 (sent to an exhaust gas treatment device). According to this configuration, the heat from the microwave oscillator 21 and the heat of the exhaust gas can be used for preheating, thereby improving the preheating efficiency. [Explanation of symbols]

[0030] 1. Sintered body manufacturing equipment 2. Microwave heating device 3 Preheater 4 Air-cooled cooling device 5 Object to be heated 6 Roller conveyor 21 Microwave Oscillator 22 Waveguide 23 Microwave heating furnace

Claims

1. a microwave oscillator that generates microwaves; a waveguide connected to the microwave oscillator; a microwave heating furnace through which the microwave is propagated via the waveguide, A sintered body manufacturing apparatus including a microwave heating device that heats an object to be heated in the microwave heating furnace with the microwaves, an air-cooling type cooling device that supplies cooling air to the microwave oscillator; a preheater that preheats the object to be heated with air that is supplied from the air-cooling device to the microwave oscillator and recovers heat generated by the microwave oscillator; A sintered body manufacturing apparatus comprising:

2. 2. The sintered body manufacturing apparatus according to claim 1, wherein the object to be heated is passed through the preheater by a roller conveyor and then introduced into the microwave heating furnace.

3. The object to be heated is a mixture of coal ash and a Ca source, 3. The sintered body manufacturing apparatus according to claim 1, wherein in the microwave heating furnace, the mixture preheated in the preheater is irradiated with the microwaves in a carbon dioxide atmosphere.

4. 4. The sintered body manufacturing apparatus according to claim 3, wherein the coal ash is fly ash, and the Ca source is waste concrete powder.

5. a microwave oscillator that generates microwaves; a waveguide connected to the microwave oscillator; a microwave heating furnace through which the microwave is propagated via the waveguide, a sintered body manufacturing method for manufacturing a sintered body by a microwave heating device that heats an object to be heated in the microwave heating furnace with the microwaves, At a stage before the object to be heated is heated by the microwave, the object to be heated is preheated by air that is supplied to the microwave oscillator and has recovered heat generated by the microwave oscillator. A method for producing a sintered body.

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