JPS62102080A - High-temperature continuous reaction furnace - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention is a high-temperature continuous reactor, in particular, a method for continuously reacting at high temperatures that is useful for the synthesis of silicon nitride, boron nitride, etc. as ceramic raw materials. This invention relates to a high-temperature continuous reactor using a pusher-equipped tunnel furnace for carrying out the following steps.

(Conventional technology) In recent years, the production of ceramic raw materials such as silicon nitride and boron nitrite has required particularly high purity. Therefore, in place of the conventional Acheson furnace, it is easy to adjust the atmospheric conditions and 6A degree. The method is being converted to one using a certain Busher tunnel furnace.

However, this pusher-equipped tunnel furnace is one in which a reaction vessel filled with raw materials is continuously transferred into the furnace for reaction, and most of these are equipped with displacement chambers on the inlet and outlet sides. Although the atmosphere inside the furnace is strictly controlled, since the reaction vessel used in this method has a small capacity, production is usually carried out continuously over long periods of time.

However, in this type of reactor, the reaction vessel that moves inside the reactor is usually open at the top, so if this is used to continue the reaction for a long period of time, 1) the reaction raw materials, their decomposed products, and by-products; , and C is scattering of reaction products, vapor deposition 1: Therefore, these adhere to and accumulate on various parts of the furnace and the heating element, making it impossible to transport the container or causing the heater to burn out.
The furnace body is also damaged. 2) There are many accidents where the furnace body is damaged or the heater burns out due to high-temperature atmospheric gas and gases generated due to side reactions, making long-term operation impossible. There is a disadvantage that it disappears.

(Structure of the Invention) The present invention relates to a high-temperature continuous reactor that solves the above-mentioned disadvantages, in which a reaction vessel charged with a raw material and having an opening only in the direction of movement is placed in a busher type tunnel furnace. It is characterized in that after the reaction vessel is connected continuously to form a muffle shape, the reaction gas is caused to flow therethrough while moving the reaction vessel.

That is, the present inventors have studied various ways to solve the disadvantages of the Busher type tunnel furnace as described above, and have found the following: After charging the raw material into the tunnel furnace, the raw material is continuously charged/connected to the tunnel furnace to form a matzuru shape, and then the reaction gas is fed into the tunnel furnace. The reaction gas introduced here flows only through the reaction vessel, so the reaction between the raw materials and the reaction gas in the reaction vessel is ensured. The decomposition products and byproducts generated in the reaction gas C2 are discharged from the furnace through the outlet provided in the low-temperature section, and the reaction raw materials, byproducts, and reaction products are further removed from this reactor. We discovered that since there is no scattering outside the reactor, there is no risk of damage to the reactor or heater burnout. The research progressed and the present invention was completed.

As mentioned above, the high-temperature continuous reactor of the present invention uses a reaction vessel having an opening only in the direction of movement.
The shape of this reaction container may be any shape such as a rectangular parallelepiped, a cube, or a cylinder, as long as it can form a continuous matzuru.

That is, this thing has the shape and structure shown in FIG. 1, for example, but this thing has the left and right wall surfaces (the two are An opening 1 is provided, and both side surfaces 2, ceiling surface 3, and bottom surface 4 that are perpendicular to the direction of movement have a completely closed shape and structure, but the ceiling surface etc. must be kept airtight and heated. A carbon lid structure may be provided to block heat from the source.

In the reactor of the present invention, these reaction vessels are continuously charged into a tunnel furnace, and by connecting them, the reaction vessel 14 mounted on the vessel inlet 13 is driven by the matsuflu drive device 12, which is sequentially driven. They are connected to form a matsufuru shape, and since shielding cloths 15 and 16 are provided on the inlet and outlet sides of the furnace, the central part of the furnace is a low-temperature area, the container inlet part 13 and the outlet part 17. And the atmosphere is blocked off.

Further, this furnace 11 is provided with a container take-out part 17 on its exit side, and a heating heater 18 for maintaining the inside of the reactor at a desired reaction temperature is provided in the furnace. Second is a reaction gas inlet 19, and in the center of the furnace is a gas inlet 2 for introducing a reaction gas or an inert gas.
0 is further (2) This inlet side low temperature part f2 is the gas outlet 21
is provided.

Note that the furnace material constituting this reactor 11, the heating heater, and the material forming the reaction vessel may be made of any material, but in order for this reactor to synthesize ceramic raw materials, it is usually
Since it is operated at a high temperature of 00 to 2,200 degrees Celsius, it is best to use heat-resistant materials for this furnace, such as alumina, carbon,
Boron nitride, mullite, zircon, silicon nitride, etc. are preferably used, and the heater is preferably made of silicon carbide, tungsten, carbon, etc.; Depending on the desired product and the type of raw material, it may be made of silicon nitride, carbon, alumina, etc. The raw material charged into this reaction vessel is usually in solid form, but it may be charged in the form of briquettes or lumps if necessary.

In order to carry out a reaction in this high-temperature continuous reactor 11, raw materials are charged into the reaction vessel 14, and then loaded onto the vessel inlet 13, and then transferred into the furnace on a continuous surface by the vessel drive device 12. After it is moved to form a pine-like shape, the inside of the furnace is heated to a predetermined temperature by the heating heater 18, and then the reaction gas is introduced from the reaction gas inlet 19. In this way, the reaction gas flows into the reaction vessel. Since it passes through the opening 1 provided at +4 into the connected reaction vessel 14, the desired reaction takes place in the reaction vessel 14, and the reaction product obtained in this reaction is When the reaction container 14 arrives at the container removal section 11, it is taken out as two products.

In this case, if this reaction is carried out under an inert gas atmosphere, the central part of the furnace I: the gas inlet 2 provided is
If an inert gas is added from 0 at a pressure that is slightly higher than that of the reaction vessel, the inert gas will flow into the reaction vessel from the connecting part of the reaction vessel 14, so the purpose can be achieved. Depending on the purpose, a reactive gas may be introduced from the gas inlet 20 instead of the inert gas.

The reaction in the high-temperature continuous reactor of the present invention is carried out as described above. According to this, the reaction vessel 14 has an opening l only in the direction of movement within the tunnel furnace, and the reaction gas is The reaction vessel 14 runs vertically through the inside of the reactor through the reactor, so the exhaust gas from this reaction is followed by the reaction gas and discharged out of the system from the gas exhaust port 21. Since the bottom is completely sealed, raw materials, their decomposition products, reaction by-products, etc. will not scatter or evaporate and will not adhere to the furnace inner wall or heating heater, preventing cracked gas, by-product gas, etc. Since these substances are discharged from the exhaust port as exhaust gas, the inside of the furnace will not be contaminated or damaged by these substances, and therefore, the conveyance of containers will not stop or the heater will not burn out, making long-term operation possible. gender is given.

Next, examples of the present invention will be given.

Example 1, Comparative Example 1 Silicon tetrachloride and ammonia were reacted in a 15 m long high-temperature continuous reactor as shown in Fig. 2, using alumina as the furnace material and equipped with a tungsten heater. 3KP of silicon imide briquettes in an inert atmosphere
Charged internal volume 2 made of silicon nitride as shown in Figure 1
After installing a 0g reaction vessel, nitrogen gas is injected into the furnace from the gas inlet at the center of the furnace at a pressure of 50 mm of water to create a nitrogen gas atmosphere, and the temperature of the hottest part of the furnace is set to 1. 4
The reactor is heated to maintain the temperature at 00°C, and then the reactor is driven by a container drive device at such a speed that one reactor passes through the hottest part of the furnace in 120 minutes to form a pine-flour-like shape, and When nitrogen gas containing 5% hydrogen gas was introduced at a rate of 251/min from the reaction gas inlet provided on the outlet side and reacted, 1.3 tons of silicon nitride was removed.
After three months of continuous operation, we dismantled the furnace and examined the wear and tear on the furnace materials and heater, and found no wear and tear on the furnace walls. Ta.

However, when the reaction was carried out in the same manner as above except that a reaction vessel of the same capacity with only the top open was used as the reaction vessel, in this case ammonium chloride and
Due to the deposition of silica, the reaction had to be stopped 56 hours after the start of the reaction (secondly, the transport system broke down and the reaction was stopped).

Example 2, Comparative Example 2 Silicon metal was placed in a high-temperature continuous reactor as shown in Fig. 2, which had a length of 137 nm and was equipped with a heater made of carbon electrodes and a furnace material made of carbon, mainly carbon felt. After installing a reaction vessel made of silicon nitride with an internal volume of 151 cm as shown in Fig. 1 and charged with 0.7 KF, nitrogen gas was injected into the furnace from the gas inlet in the center of the furnace. A nitrogen gas atmosphere of 50 mm of water was created inside the reactor, and the temperature of the soaking section inside the furnace was maintained at 1,300°C, and then one reaction vessel passed through the soaking section inside the furnace in 240 minutes. A container driving device is used to drive the container at such a speed as to make it into a matte shape, and a 1:1 mixed gas of nitrogen gas and ammonia gas is supplied from the reactant gas inlet provided on the furnace outlet side.
When the reaction was carried out by feeding the furnace at a rate of /min, silicon nitride could be obtained at It/month.After three months of continuous operation, the furnace was dismantled and the furnace materials and heaters were no longer consumed. wood,
The heater showed no wear and there were no deposits in the furnace.

However, for comparison, a reaction vessel of the same capacity with only the top open was used as the reaction vessel in Mine - above 1.
The electrode broke on the first day, so operations were stopped and the furnace was dismantled to find that all the carbon heaters had become thin and thin and had been cut off in some places, and the furnace walls were also severely worn out.

Example 3, Comparative Example 3 Reaction in the same tunnel furnace as in Example 2, made of carbon and having an internal volume 301 as shown in FIG. After installing the customer equipment, nitrogen gas is injected from the gas inlet in the center of the furnace to create a nitrogen gas atmosphere of 50 water columns inside the furnace, and the temperature of the soaking section inside the furnace is maintained at 2.000°C. Then, this reaction vessel was driven using a vessel driving device at such a speed that one reaction vessel passed through the in-furnace soaking section in 1,200 minutes to form a matzuru shape. Inject nitrogen gas containing 5% ammonia from the reaction gas inlet into 501/
When the reaction was carried out by feeding the furnace at a rate of 30 minutes, boron nitride could be obtained at 1 t/month. After 3 months of continuous operation, the furnace was dismantled and the wear and tear of the furnace materials and heaters was examined. There was no evidence of wear and tear on the wood or heater, and there was no buildup inside the furnace.

However, for comparison (2), we conducted the reaction in the same manner as above except for using a reaction vessel with only the top open; in this case, most of the carbon heaters were removed on the 3rd day after the start of the reaction. When the burnout occurred, we stopped operations and dismantled the furnace.We found that both the furnace material and the carbon heater were worn out, and there was a significant amount of white deposits on the furnace wall.

[Brief explanation of drawings]

Figure @1 is a perspective view of a reaction vessel used in the high-temperature continuous reactor of the present invention, and Figure '@2 is a vertical IIJT view of this reactor. DESCRIPTION OF SYMBOLS 1... Opening part, -2... Side wall part, 3... Ceiling part, 4... Bottom part, 11... Reactor, 12...
- Container driving device, 14... Reaction container, 19...
Reaction gas inlet, 20... Gas inlet, 21...
Gas outlet. Patent applicant Shin-Etsu Chemical Co., Ltd. Figure 1 Figure 2

Claims (1)

[Claims] 1. A reaction vessel charged with a raw material and having an opening only in the direction of movement is continuously connected in a Busher tunnel furnace to form a muffle, and then the reaction vessel is moved. A high-temperature continuous reactor characterized in that a reactant gas is circulated throughout the reactor. 2. The high-temperature continuous reactor according to claim 1, wherein a furnace atmosphere gas discharge port is provided in a low-temperature portion of the furnace.