Combustion synthesis apparatus

Abstract

To provide a combustion synthesis apparatus capable of accurately cooling and purifying the atmosphere in a furnace in a short time.SOLUTION: A combustion synthesis apparatus (1) according to the present invention includes: a combustion synthesis furnace (2); and a circulation mechanism (3) which is attached to the outside of the combustion synthesis furnace and circulates an atmosphere in the combustion synthesis furnace, wherein the circulation mechanism includes: a first heat exchanger (4) connected to a gas outlet side in the combustion synthesis furnace; a second heat exchanger (7) connected to a gas inlet side in the combustion synthesis furnace; a purifier (5) connected between the first heat exchanger and the second heat exchanger; and a compressor (6) connected between the purifier and the second heat exchanger.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a combustion synthesis apparatus for synthesizing inorganic compounds by a combustion synthesis method, and particularly relates to a cooling system.

Background Art

[0002] As a cooling system for a combustion synthesis furnace, conventionally, a method of cooling the atmosphere in the chamber by a jacket structure of the reaction chamber, a method of cooling the stage where the crucible is installed, or a method of circulating and cooling the atmosphere in the furnace is known.

[0003] For example, Patent Document 1 discloses an invention related to a combustion synthesis apparatus using a cooling means for forcibly cooling a reaction vessel. Further, Patent Document 2 discloses an invention related to an aluminum nitride production apparatus provided with a circulation mechanism inside a combustion synthesis furnace for cooling.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the inventions described in Patent Documents 1 and 2, since it is a system for cooling the atmosphere by arranging a cooling mechanism inside the combustion synthesis furnace, due to the limitation of the furnace inner area, the heat exchange efficiency cannot be effectively increased, and there is a problem of slow cooling rate.

[0006] Furthermore, combustion synthesis requires both cooling and purification of the furnace. That is, it is necessary to properly remove corrosive and odorous gases produced in the combustion synthesis reaction. Patent Document 2 describes capturing impurities in a cooling unit installed inside the furnace to reduce the impurity concentration in the atmospheric gas. However, it is predicted that it will take a considerable amount of time for the circulating atmospheric gas to come into contact with the cooling unit placed on the furnace wall and for the impurities to be removed, or it may be difficult to sufficiently remove impurities from the circulating atmospheric gas.

[0007] Therefore, the present invention has been made in view of the above problems, and aims to provide a combustion synthesis apparatus that can cool and purify the atmosphere inside the furnace in a short time and with high precision. [Means for solving the problem]

[0008] The combustion synthesis apparatus of the present invention, Combustion synthesis is performed. A combustion synthesis furnace and an attachment mounted on the outside of the combustion synthesis furnace, While performing the aforementioned combustion synthesis The combustion synthesis furnace comprises a circulation mechanism for circulating the atmosphere inside the furnace, the circulation mechanism comprising: a first heat exchanger connected to the gas outlet side of the combustion synthesis furnace; a second heat exchanger connected to the gas inlet side of the combustion synthesis furnace; a purification device connected between the first heat exchanger and the second heat exchanger; and a compressor connected between the purification device and the second heat exchanger. The first heat exchanger, the purification device, the compressor, and the second heat exchanger are connected in series from the gas outlet side, and the atmosphere inside the combustion synthesis furnace is circulated through the circulation mechanism by the pressure-boosting action of the compressor, and the atmosphere inside the combustion synthesis furnace cooled in the first heat exchanger is taken into the purification device, which purifies corrosive or odorous gases generated in the combustion synthesis reaction and recovers particulate matter generated during the combustion synthesis and floating in the atmosphere, and the heat generated from the compressor is cooled in the second heat exchanger. It is characterized by the following:

[0009] In the present invention, it is preferable that the reaction gas supply source is branched and connected between the second heat exchanger and the gas inlet. In the present invention, a vacuum pump is branched and connected between the first heat exchanger and the gas outlet. The vacuum pump then evacuates the inside of the combustion synthesis furnace. It is preferable.

[0010] In the present invention, the combustion synthesis furnace preferably comprises a chamber and a multi-stage rack for installing a plurality of crucibles within the chamber, and cold air nozzles for supplying cold air from the gas inlet to each stage of the multi-stage rack are connected. [Effects of the Invention]

[0011] According to the combustion synthesis apparatus of the present invention, a circulation mechanism is provided outside the combustion synthesis furnace, and a heat exchanger, a purification device, and a compressor are arranged in a predetermined order within the circulation mechanism. This makes it possible to cool and purify the furnace atmosphere quickly and accurately. [Brief explanation of the drawing]

[0012] [Figure 1] This is an overall schematic diagram of the combustion synthesis apparatus in this embodiment. [Figure 2] This is a flowchart illustrating the opening and closing timings of each valve provided in the combustion synthesis apparatus in this embodiment. [Figure 3] This is a perspective side view showing the internal structure of the combustion synthesis furnace in this embodiment. [Modes for carrying out the invention]

[0013] Hereinafter, one embodiment of the present invention (hereinafter abbreviated as "Embodiment") will be described in detail. It should be noted that the present invention is not limited to the following embodiment, and can be implemented with various modifications within the scope of its gist.

[0014] Figure 1 is an overall schematic diagram of the combustion synthesis apparatus 1 in this embodiment. As shown in Figure 1, the combustion synthesis apparatus 1 comprises a combustion synthesis furnace 2 and a circulation mechanism 3 attached to the outside of the combustion synthesis furnace 2 for circulating the atmosphere inside the combustion synthesis furnace 2.

[0015] As shown in Figure 1, the circulation mechanism 3 comprises a first heat exchanger 4, a purification device 5, a compressor 6, and a second heat exchanger 7. The first heat exchanger 4 is connected to the gas outlet 2a of the combustion synthesis furnace 2 via a first main pipe 8. The second heat exchanger 7 is connected to the gas inlet 2b of the combustion synthesis furnace 2 via a second main pipe 9.

[0016] As shown in Fig. 1, a purification device 5 and a compressor 6 are provided between the first heat exchanger 4 and the second heat exchanger 7, and they are connected in series in the order of the first heat exchanger 4 - purification device 5 - compressor 6 - second heat exchanger 7.

[0017] Existing devices can be used for the first heat exchanger 4 and the second heat exchanger 7. Also, existing devices can be used for the compressor 6 as well. For example, an existing nitrogen booster can be used. Due to the pressure boosting effect of the compressor 6, the atmosphere in the combustion synthesis furnace 2 can be circulated through the externally installed circulation mechanism 3. In particular, by using the compressor 6, the circulating flow rate can be increased compared to the case where the inside of the combustion synthesis furnace 2 is circulated using a propeller or the like. However, heat is generated due to the pressure boosting effect of the compressor 6. Therefore, it is necessary to cool the heat generated from the compressor 6 in the circulation mechanism 3, and the second heat exchanger 7 is arranged between the compressor 6 and the gas inlet 2b. Thereby, the second heat exchanger 7 can remove the heat generated by the compressor 6 and introduce cold air into the combustion synthesis furnace 2 through the second main pipe 9.

[0018] In this embodiment, not only the cooling system but also the purification system is incorporated into the circulation mechanism 3. That is, as shown in Fig. 1, the purification device 5 is arranged between the first heat exchanger 4 and the compressor 6. The purification device 5 can purify corrosive gases, odorous gases, etc. generated in the synthesis reaction, and can also recover fine particles generated during synthesis and floating in the atmosphere in the furnace. The structure of the purification device 5 is not limited, but as an example, it can be composed of a multilayer structure. For example, it can be composed of a layer structure of a filter, a deoxidizing material (slaked lime), and activated carbon, and it is possible to perform fiber recovery, purification of hydrochloric acid, ammonia, etc. Thereby, corrosive gases and odorous gases in the combustion synthesis furnace 2 can be effectively removed, and the crucible from which the combustion synthesis has ended can be safely taken out from the combustion synthesis furnace 2. Also, the recovered fiber can be reused.

[0019] As shown in FIG. 1, the first heat exchanger 4 is connected to the gas outlet 2a side of the purification device 5. As a result, the atmosphere in the combustion synthesis furnace 2 cooled by the first heat exchanger 4 is taken into the purification device 5, so the purification device 5 is not affected by the heat in the furnace. In addition, the purification device 5 is connected to the first heat exchanger 4 side from the compressor 6. Therefore, the purification device 5 is not affected by the heat generated by the compressor 6 either. For this reason, even if high-temperature gas flows into the circulation mechanism 3 from the gas outlet 2a of the combustion synthesis furnace 2 and heat is generated due to the compression operation of the compressor 6, due to the connection order of the heat exchangers 4 and 7, the purification device 5, and the compressor 6, the purification device 5 is not affected by heat and can operate normally for a long time.

[0020] As described above, in the present embodiment, the atmosphere in the combustion synthesis furnace 2 is taken out and cooled externally, and the circulation mechanism 3 that returns the cold air into the combustion synthesis furnace 2 can substantially increase the cooling area. That is, for example, in a configuration where a cooling jacket is installed in the furnace, only the jacket area is the cooling area. In contrast, in the present embodiment, by arranging the heat exchangers 4 and 7 outside the combustion synthesis furnace 2, the cooling area can be increased according to the capabilities of the heat exchangers 4 and 7. Moreover, in the present embodiment, the compressor 6 is arranged in the circulation mechanism 3 to increase the circulation flow rate. As a result, the cooling speed can be increased. In addition, by exhausting the atmosphere in the furnace from the upper part of the combustion synthesis furnace 2 and introducing the pressurized cold air into the furnace from the gas inlet 2b located at the lower part of the combustion synthesis furnace 2, the atmosphere in the furnace can be circulated appropriately, and the heat dissipation from the synthesized body generated by combustion synthesis can also be promoted.

[0021] Also, in the present embodiment, the purification device 5 is arranged in the circulation mechanism 3 and connected between the first heat exchanger 4 and the compressor 6. As a result, the atmosphere in the combustion synthesis furnace 2 can be purified by external piping and returned to the furnace, the synthesized body can be safely taken out of the furnace after synthesis is completed, and the purification device 5 can be appropriately protected from the heat in the combustion synthesis furnace 2 and the heat of the compressor 6.

[0022] As shown in Figure 1, a reaction gas supply source 10 is connected between the second heat exchanger 7 and the gas inlet 2b of the combustion synthesis furnace 2. The reaction gas supply source 10 is, for example, a gas cylinder, and when AlN is produced in the combustion synthesis furnace 2, nitrogen-containing gas is supplied from the reaction gas supply source 10 to the combustion synthesis furnace 2.

[0023] Furthermore, as shown in Figure 1, a vacuum pump 11 is connected between the first heat exchanger 4 and the gas outlet 2a. This vacuum pump 11 is used to create a vacuum inside the combustion synthesis furnace 2.

[0024] In this embodiment, the reaction gas supply source 10 and the vacuum pump 11 are connected to the piping path of the circulation mechanism 3, which has heat exchangers 4 and 7, a purification device 5, and a compressor 6. The combustion synthesis furnace 2 can be supplied with reaction gas and vacuumed through the gas outlet 2a and gas inlet 2b, in addition to cooling and purification circulation. It is preferable that d1 ≥ d2 when the diameter of the gas outlet 2a is d1 and the diameter of the gas inlet 2b is d2. This allows for faster vacuuming.

[0025] The piping and valves attached to the piping of the circulation mechanism 3 shown in Figure 1 will now be described. As shown in Figure 1, valve V1 is attached to the first main pipe 8 that connects the first heat exchanger 4 and the gas outlet 2a. On the gas outlet 2a side of valve V1, the first sub-pipe 12 branches off from the first main pipe 8, and valve V2 is attached to the first sub-pipe 12. Also, as shown in Figure 1, the second sub-pipe 13 branches off from the first main pipe 8 between the first sub-pipe 12 and valve V1, and a vacuum pump 11 is connected to the second sub-pipe 13. Valve V3 is attached to the second sub-pipe 13.

[0026] As shown in Figure 1, a valve V4 is attached to the second main pipe 9 connecting the second heat exchanger 7 and the gas inlet 2b. Further along the gas inlet 2b side of valve V4, a third sub-pipe 14 branches off from the second main pipe 9, and a reaction gas supply source 10 is connected to the third sub-pipe 14. A valve V5 is attached to the third sub-pipe 14. Furthermore, as shown in Figure 1, the combustion synthesis furnace 2 is equipped with a furnace pressure determination unit 16 and a temperature determination unit 15, making it possible to measure the pressure and temperature inside the furnace.

[0027] Using the flowchart shown in Figure 2, we will explain the furnace adjustments from the preparation process before combustion synthesis to after synthesis. In step ST1 shown in Figure 2, valve V2 is closed to start gas replacement. At this time, valve V1 is also closed. In step ST2 shown in Figure 2, valve V3 is opened to start vacuuming. In step ST3 shown in Figure 2, the pressure inside the combustion synthesis furnace 2 is measured by the furnace pressure determination unit 16, and when the pressure is in the range of, for example, 50 to 100 Pa, valve V3 is closed. This allows vacuuming to be performed through the first main pipe 8.

[0028] Next, in step ST4 shown in Figure 2, valve V5 is opened, and nitrogen-containing gas is supplied from the reaction gas supply source 10 into the combustion synthesis furnace 2 through the second main pipe 9. At this time, valve V4 is closed. Subsequently, in step ST5 shown in Figure 2, when the furnace pressure determination unit 16 determines that the pressure inside the combustion synthesis furnace 2 has reached the synthesis set pressure, valve V5 is closed. Note that the synthesis set pressure inside the furnace fluctuates due to synthesis and atmosphere circulation, so the furnace pressure is adjusted by opening and closing valve V5 (step ST6).

[0029] In step ST7 of Figure 2, valves V1 and V4 of main pipes 8 and 9 are opened, and combustion synthesis is performed while circulating the furnace atmosphere. The furnace atmosphere is circulated by the circulation mechanism 3, and cooling and purification are carried out.

[0030] In step ST8 of Figure 2, the temperature determination unit 15 determines the temperature inside the combustion synthesis furnace 2. The temperature determination unit 15 is equipped with, for example, a thermocouple, which measures the temperature near the end of the raw materials placed inside the combustion synthesis furnace 2 (the location furthest from the ignition point). When the temperature measured by the thermocouple begins to decrease, the temperature determination unit 15 determines that the combustion synthesis has ended, closes the valve V5, and stops the supply of nitrogen-containing gas.

[0031] Next, in step ST9 of Figure 2, the temperature determination unit 15 measures the temperature inside the combustion synthesis furnace 2. When the temperature cools to below a predetermined level, it is determined that cooling is complete, and valves V1 and V4 are closed. In step ST10 of Figure 2, valve V2 is opened to release the gas to the atmosphere and reduce the pressure to atmospheric pressure. This completes the combustion synthesis (step ST11).

[0032] In the event of an emergency shutdown, such as when an abnormality occurs in the combustion synthesis furnace 2, only valve V2 will be opened to release the gas into the atmosphere.

[0033] As shown in Figure 2, by opening and closing each valve, vacuuming, introduction of reaction gases, and circulation of the furnace atmosphere (operation of the cooling system and purification system) can be performed through the main pipes 8 and 9.

[0034] Figure 3 is a perspective side view showing the internal structure of the combustion synthesis furnace 2 in this embodiment. Specifically, Figure 3 is a perspective side view of the chamber 24 that constitutes the combustion synthesis furnace 2. As shown in Figure 3, the combustion synthesis furnace 2 is composed of a multi-stage rack 22 on which multiple crucibles 21 can be installed in multiple stages, a stage 23 on which the multi-stage rack 22 is placed, and a chamber 24 that can accommodate the multi-stage rack 22 and the stage 23.

[0035] As shown in Figure 3, a first main pipe 8 is connected to the gas outlet 2a, allowing exhaust through the first main pipe 8. A second main pipe 9 is connected to the gas inlet 2b, and a cold air nozzle 25 is connected to the end of the second main pipe 9. The cold air nozzle 25 is located inside the combustion synthesis furnace 2. As shown in Figure 3, the cold air nozzle 25 is provided with multiple outlets 25a, each outlet 25a facing the gap between each stage of the multi-stage rack 22. This allows cold air to be sent from each outlet 25a between each stage, thus increasing cooling efficiency and more effectively shortening the cooling time.

[0036] In this embodiment, a cooling unit such as a cooling jacket may be placed inside the furnace as an auxiliary measure. The cooling unit captures corrosive and odorous gases, reducing their concentration in the atmosphere and allowing them to be purified by the circulation mechanism 3, thereby increasing the purification efficiency. [Industrial applicability]

[0037] The present invention can be suitably applied to the cooling system of a combustion synthesis furnace for producing inorganic compounds. [Explanation of symbols]

[0038] 1: Combustion synthesis apparatus 2: Combustion synthesis furnace 2a: Gas outlet 2b: Gas inlet 3: Circulation mechanism 4: First heat exchanger 5: Purification device 6: Compressor 7: Second heat exchanger 8: First main pipe 9: Second main pipe 10: Reaction gas supply source 11: Vacuum pump 12: First secondary piping 13: Second auxiliary piping 14: Third auxiliary piping 15:Temperature judgment section 16: Furnace pressure determination unit 21: Crucible 22: Multi-tiered rack 23: Stage 24: Chamber 25: Cold air nozzle 25a: Air outlet V1~V5: Valve

Claims

1. A combustion synthesis furnace for performing combustion synthesis, and a circulation mechanism attached to the outside of the combustion synthesis furnace for circulating the atmosphere inside the combustion synthesis furnace while performing combustion synthesis, The aforementioned circulation mechanism is A first heat exchanger connected to the gas outlet side within the combustion synthesis furnace, A second heat exchanger connected to the gas inlet side of the combustion synthesis furnace, A purification device connected between the first heat exchanger and the second heat exchanger, The device includes a compressor connected between the purification device and the second heat exchanger, The first heat exchanger, the purification device, the compressor, and the second heat exchanger are connected in series from the gas outlet side, Due to the pressure-boosting action of the compressor, the atmosphere inside the combustion synthesis furnace is circulated through the circulation mechanism. From the first heat exchanger to the purification device, the atmosphere inside the combustion synthesis furnace cooled by the first heat exchanger is taken into the purification device. The aforementioned purification device purifies corrosive or odorous gases generated in the combustion synthesis reaction and recovers particulate matter generated during the combustion synthesis and floating in the atmosphere. In the second heat exchanger, the heat generated from the compressor is cooled. A combustion synthesis apparatus characterized by the following features.

2. The combustion synthesis apparatus according to claim 1, characterized in that a reaction gas supply source is branched and connected between the second heat exchanger and the gas inlet.

3. The combustion synthesis apparatus according to claim 1 or 2, characterized in that a vacuum pump is branched and connected between the first heat exchanger and the gas outlet, and the inside of the combustion synthesis furnace is evacuated by the vacuum pump.

4. The combustion synthesis furnace comprises a chamber and a multi-tiered rack for installing a plurality of crucibles within the chamber. The combustion synthesis apparatus according to claim 1 or 2, characterized in that a cold air nozzle for supplying cold air between each tier of the multi-tier rack is connected from the gas inlet.

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