JP2024030670A - Combustion synthesis equipment - Google Patents

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

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

Conventional cooling systems for combustion synthesis furnaces include a method of cooling the atmosphere inside the chamber using a jacket structure of the reaction chamber, a method of cooling the stage where the crucible is installed, or a method of cooling the atmosphere inside the furnace by circulating it. etc. are known.

For example, Patent Document 1 discloses an invention related to a combustion synthesis apparatus using a cooling means for forcibly cooling a reaction vessel. Furthermore, Patent Document 2 discloses an invention relating to an aluminum nitride production apparatus that provides a circulation mechanism inside a combustion synthesis furnace to cool the interior of the combustion synthesis furnace.

Japanese Patent Application Publication No. 2000-16804 Japanese Patent Application Publication No. 2021-148350

In the inventions described in Patent Documents 1 and 2, since the system is a system that cools the atmosphere by disposing a cooling mechanism inside the combustion synthesis furnace, heat exchange efficiency cannot be effectively increased due to the restriction of the area inside the furnace. First, there was the problem of slow cooling speed.

In addition, combustion synthesis requires cooling and purification within the furnace. That is, it is necessary to appropriately remove corrosive gases, odorous gases, etc. generated in combustion synthesis reactions. Patent Document 2 describes that impurities are captured by a cooling section installed in the furnace to reduce the impurity concentration in the atmospheric gas. It is predicted that it will take a considerable amount of time for the gases to come into contact and impurities are removed, or it is considered that it is difficult to sufficiently remove impurities in the circulating atmospheric gas.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a combustion synthesis apparatus that can cool and purify the atmosphere within a furnace in a short time and with high accuracy.

The combustion synthesis apparatus of the present invention includes a combustion synthesis furnace, and a circulation mechanism that is attached to the outside of the combustion synthesis furnace and circulates the atmosphere inside the combustion synthesis furnace, and the circulation mechanism is configured to circulate the atmosphere inside the combustion synthesis furnace. 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; The present invention is characterized by comprising a purification device connected between the second heat exchanger and a compressor connected between the purification device and the second heat exchanger.

In the present invention, it is preferable that a reactive gas supply source is branched and connected between the second heat exchanger and the gas inlet.
In the present invention, it is preferable that a vacuum pump is branched and connected between the first heat exchanger and the gas outlet.

In the present invention, the combustion synthesis furnace includes a chamber and a multi-stage rack for installing a plurality of crucibles in the chamber, and cool air is supplied between the gas inlet and each stage of the multi-stage rack. Preferably, a cold air nozzle for sending the air is connected.

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 the circulation mechanism in a predetermined order. This makes it possible to cool and purify the atmosphere in the furnace in a short time and with high precision.

FIG. 1 is an overall schematic diagram of a combustion synthesis apparatus in this embodiment. FIG. 3 is a flowchart diagram for explaining the opening/closing timing of each valve provided in the combustion synthesis device in the present embodiment. FIG. 2 is a perspective side view showing the internal structure of the combustion synthesis furnace in the present embodiment.

Hereinafter, one embodiment of the present invention (hereinafter abbreviated as "embodiment") will be described in detail. Note that the present invention is not limited to the following embodiments, and can be implemented with various modifications within the scope of the gist.

FIG. 1 is an overall schematic diagram of a combustion synthesis apparatus 1 in this embodiment. As shown in FIG. 1, the combustion synthesis apparatus 1 includes a combustion synthesis furnace 2 and a circulation mechanism 3 that is attached to the outside of the combustion synthesis furnace 2 and circulates the atmosphere inside the combustion synthesis furnace 2.

As shown in FIG. 1, the circulation mechanism 3 includes 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 2 a of the combustion synthesis furnace 2 via a first main pipe 8 . Further, the second heat exchanger 7 is connected to the gas inlet 2b of the combustion synthesis furnace 2 via a second main pipe 9.

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 the first heat exchanger 4 - purification device 5 - compression The heat exchanger 6 and the second heat exchanger 7 are connected in series in this order.

Existing devices can be used for the first heat exchanger 4 and the second heat exchanger 7. Moreover, an existing device can be used for the compressor 6, for example, an existing nitrogen booster or the like can be used. Due to the pressure boosting action of the compressor 6, the atmosphere inside the combustion synthesis furnace 2 can be circulated through the circulation mechanism 3 installed outside.In particular, by using the compressor 6, the atmosphere inside the combustion synthesis furnace 2 can be The circulating flow rate can be increased compared to when circulating using a propeller or the like. However, heat is generated due to the pressure increasing action of the compressor 6. Therefore, it is necessary to cool down the heat generated from the compressor 6 within the circulation mechanism 3, and a second heat exchanger 7 is disposed between the compressor 6 and the gas inlet 2b. Thereby, the heat generated by the compressor 6 can be removed by the second heat exchanger 7, and cold air can be introduced into the combustion synthesis furnace 2 through the second main pipe 9.

In this embodiment, the circulation mechanism 3 incorporates not only a cooling system but also a purification system. That is, as shown in FIG. 1, a purifying device 5 is disposed 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 collect fine particles generated during the synthesis and floating in the atmosphere in the furnace. Although the structure of the purifying device 5 is not limited, as an example, it can be composed of a multilayer structure. For example, it can be configured with a layered structure of a filter, a deoxidizing material (slaked lime), and activated carbon, and it is possible to recover fibers and purify hydrochloric acid and ammonia. Thereby, corrosive gases and odorous gases in the combustion synthesis furnace 2 can be effectively removed, and the crucible in which combustion synthesis has been completed can be safely taken out from the combustion synthesis furnace 2. Additionally, the recovered fibers can be reused.

As shown in FIG. 1, the first heat exchanger 4 is connected closer to the gas outlet 2a than the purifier 5. As a result, the atmosphere inside 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 inside the furnace. In addition, the purifier 5 is connected closer to the first heat exchanger 4 than the compressor 6. Therefore, the purifier 5 is not affected by the heat generated by the compressor 6. Therefore, even if high-temperature gas flows into the circulation mechanism 3 from the gas discharge port 2a of the combustion synthesis furnace 2 and heat is generated due to the compression operation of the compressor 6, the heat exchangers 4, 7 and the purification device 5 and the compressor 6, the purifier 5 is not affected by heat and can operate normally for a long period of time.

As described above, in this embodiment, the cooling area can be substantially increased by the circulation mechanism 3 that takes out the atmosphere inside the combustion synthesis furnace 2 to the outside, cools it, and returns the cold air into the combustion synthesis furnace 2. . That is, for example, in a configuration in which a cooling jacket is installed in the furnace, only the area of the jacket is the cooling area. On the other hand, in this embodiment, by arranging the heat exchangers 4 and 7 outside the combustion synthesis furnace 2, the cooling area can be increased according to the capacity of the heat exchangers 4 and 7. Moreover, in this embodiment, the compressor 6 is disposed in the circulation mechanism 3 to increase the circulation flow rate. With the above, the cooling rate can be increased. In addition, the atmosphere inside the furnace is evacuated from the upper part of the combustion synthesis furnace 2, and pressurized cold air is introduced into the furnace from the gas inlet 2b located at the lower part of the combustion synthesis furnace 2. It can be circulated appropriately and can also promote heat dissipation from the composite produced by combustion synthesis.

Further, in this embodiment, the purifying 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 inside the combustion synthesis furnace 2 can be purified by the external piping and returned to the inside of the furnace, and the composite can be safely taken out from inside the furnace after the synthesis is completed. It can be appropriately protected from the internal heat and the heat of the compressor 6.

As shown in FIG. 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 producing AlN in the combustion synthesis furnace 2, nitrogen-containing gas is supplied from the reaction gas supply source 10 to the combustion synthesis furnace 2.

Further, as shown in FIG. 1, a vacuum pump 11 is connected between the first heat exchanger 4 and the gas outlet 2a. Using this vacuum pump 11, the inside of the combustion synthesis furnace 2 is evacuated.

As described above, 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 having the heat exchangers 4 and 7, the purification device 5, and the compressor 6, and the In the synthesis furnace 2, not only cooling and purification circulation but also reaction gas supply and evacuation can be performed through the gas outlet 2a and the gas inlet 2b. Note that when the diameter of the gas outlet 2a is d1 and the diameter of the gas inlet 2b is d2, it is preferable that d1≧d2. This allows vacuuming to be performed quickly.

The piping of the circulation mechanism 3 shown in FIG. 1 and each valve attached to the piping will be explained. As shown in FIG. 1, a valve V1 is attached to the first main pipe 8 that connects the first heat exchanger 4 and the gas outlet 2a. A first sub-pipe 12 branches from the first main pipe 8 on the side closer to the gas outlet 2a than the valve V1, and a valve V2 is attached to the first sub-pipe 12. Further, as shown in FIG. 1, a second sub-piping 13 branches from the first main piping 8 between the first sub-piping 12 and the valve V1. A vacuum pump 11 is connected. A valve V3 is attached to the second sub-piping 13.

As shown in FIG. 1, a valve V4 is attached to the second main pipe 9 that connects the second heat exchanger 7 and the gas inlet 2b. Further, a third sub-piping 14 branches from the second main pipe 9 on the gas inlet 2b side of the valve V4, and a reactant gas supply source 10 is connected to the third sub-piping 14. . A valve V5 is attached to the third sub-piping 14.
Further, as shown in FIG. 1, the combustion synthesis furnace 2 is equipped with a furnace pressure determining section 16 and a temperature determining section 15, which are capable of measuring the pressure and temperature inside the furnace.

The in-furnace adjustment from the preparation step before combustion synthesis to after synthesis will be explained using the flowchart shown in FIG. In step ST1 shown in FIG. 2, valve V2 is closed to start gas replacement. At this time, the valve V1 is also in a closed state. In step ST2 shown in FIG. 2, the valve V3 is opened to start evacuation. In step ST3 shown in FIG. 2, the pressure inside the combustion synthesis furnace 2 is measured by the furnace internal pressure determining section 16, and when the pressure falls within a range of, for example, 50 to 100 Pa, the valve V3 is closed. Thereby, vacuum can be drawn through the first main pipe 8.

Next, in step ST4 shown in FIG. 2, the 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 in a closed state. Subsequently, in step ST5 shown in FIG. 2, when the furnace internal pressure determination unit 16 determines that the pressure within the combustion synthesis furnace 2 has reached the synthesis set pressure, the valve V5 is closed. Note that since the synthesis set pressure in the furnace fluctuates during synthesis and due to the circulation of the atmosphere, the pressure in the furnace is adjusted by opening and closing valve V5 (step ST6).

In step ST7 of FIG. 2, the valves V1 and V4 of the main pipes 8 and 9 are opened, and combustion synthesis is performed while circulating the atmosphere in the furnace. The atmosphere inside the furnace is circulated by the circulation mechanism 3 to perform cooling and purification.

In step ST8 of FIG. 2, the temperature determination section 15 determines the temperature inside the combustion synthesis furnace 2. The temperature determination unit 15 includes, for example, a thermocouple, and the thermocouple measures the temperature near the end of the raw material placed in the combustion synthesis furnace 2 (the farthest location from the ignition point). Then, when the temperature measured by the thermocouple starts to decrease, the temperature determining section 15 determines that combustion synthesis has ended, and closes the valve V5 to stop supplying the nitrogen-containing gas.

Subsequently, in step ST9 of FIG. 2, the temperature determination unit 15 measures the temperature inside the combustion synthesis furnace 2, and when the temperature has been cooled to a predetermined value or less, it is determined that cooling is complete and valves V1 and V4 are closed.
In step St10 of FIG. 2, the valve V2 is opened to release the air to the atmosphere, thereby reducing the pressure to normal pressure. Through the above steps, combustion synthesis is completed (step ST11).

Note that when an emergency shutdown is to be performed, such as when an abnormality occurs in the combustion synthesis furnace 2, only the valve V2 is opened to release the atmosphere.

As shown in FIG. 2, by opening and closing each valve, evacuation, introduction of reaction gas, and circulation of the atmosphere in the furnace (operation of the cooling system and purification system) can be performed through the main pipes 8 and 9.

FIG. 3 is a perspective side view showing the internal structure of the combustion synthesis furnace 2 in this embodiment. That is, FIG. 3 is a side view of the chamber 24 that constitutes the combustion synthesis furnace 2. As shown in FIG. As shown in FIG. 3, the combustion synthesis furnace 2 includes a multi-stage rack 22 in which crucibles 21 can be installed in multiple stages, a stage 23 on which the multi-stage rack 22 is placed, and a chamber 24 in which the multi-stage rack 22 and the stage 23 can be accommodated. It is composed of the following.

As shown in FIG. 3, a first main pipe 8 is connected to the gas exhaust port 2a, and the gas can be exhausted through the first main pipe 8. Further, a second main pipe 9 is connected to the gas inlet 2b, and a cold air nozzle 25 is connected to the tip of the second main pipe 9. is located inside. As shown in FIG. 3, the cold air nozzle 25 is provided with a plurality of outlets 25a, and each outlet 25a faces a gap between each stage of the multi-stage rack 22. Thereby, cold air can be sent between each stage from each outlet 25a, and therefore cooling efficiency can be increased and cooling time can be more effectively shortened.

Note that in this embodiment, a cooling section such as a cooling jacket may be additionally disposed inside the furnace. The cooling section captures corrosive gases and odorous gases, reduces the concentration of the corrosive gases and odorous gases in the atmosphere, and purifies them through the circulation mechanism 3, thereby making it possible to further increase purification efficiency. .

According to the present invention, it can be preferably applied to a cooling system for a combustion synthesis furnace that produces inorganic compounds.

1: Combustion synthesis device 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 sub-pipe 13 : Second sub-pipe 14 : Third sub-pipe 15 : Temperature determining section 16 : Furnace pressure determination unit 21 : Crucible 22 : Multi-stage rack 23 : Stage 24 : Chamber 25 : Cold air nozzle 25a : Outlet V1 to V5 : Valve

Claims (4)

A combustion synthesis furnace; a circulation mechanism that is attached to the outside of the combustion synthesis furnace and circulates the atmosphere within the combustion synthesis furnace;
The circulation mechanism is
a first heat exchanger connected to the gas outlet side in the combustion synthesis furnace;
a second heat exchanger connected to the gas inlet side in the combustion synthesis furnace;
a purification device connected between the first heat exchanger and the second heat exchanger;
A combustion synthesis device comprising: a compressor connected between the purification device and the second heat exchanger. The combustion synthesis apparatus according to claim 1, wherein a reactant 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, wherein a vacuum pump is branched and connected between the first heat exchanger and the gas outlet. The combustion synthesis furnace includes a chamber, and a multi-stage rack for installing a plurality of crucibles in the chamber,
3. The combustion synthesis apparatus according to claim 1, wherein a cold air nozzle for sending cold air from the gas inlet to each stage of the multi-stage rack is connected.

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