Gas generator and nitriding apparatus

Abstract

To reduce equipment cost and running cost of a nitriding apparatus which is configured to generate gas including hydrogen gas and nitrogen gas by decomposing raw material gas including ammonia at a low temperature in a reaction vessel, and which is configured to subject an object to be processed to nitriding treatment with ammonia gas in a furnace.SOLUTION: In a nitriding apparatus that subjects an object to be processed to nitriding treatment with ammonia gas NH3 at a temperature of 500-600°C in a furnace 20, a reaction vessel 10 accommodating a catalyst x that decomposes a raw material gas including ammonia at 500-600°C is inserted into the furnace, and gas including hydrogen gas H2 and nitrogen gas N2 obtained by decomposition in a reaction vessel is directly supplied into the furnace.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a gas generator that decomposes a source gas containing ammonia in a reaction vessel containing a catalyst to generate a gas containing hydrogen gas and nitrogen gas, and a nitriding apparatus that nitrides an object to be treated with ammonia gas in a furnace at a temperature of 500 to 600° C. In particular, the present invention is characterized in that the source gas containing ammonia is decomposed at a low temperature in the reaction vessel to generate a gas containing hydrogen gas and nitrogen gas, and when the object to be treated is nitrided in the furnace with ammonia gas at a temperature of 500 to 600° C., the gas containing hydrogen gas and nitrogen gas obtained by decomposing the source gas containing ammonia in the reaction vessel containing a catalyst is supplied into the furnace, thereby reducing the equipment costs and running costs of the nitriding apparatus. [Background technology]

[0002] Conventionally, as shown in Patent Document 1 and the like, a small cartridge type reactor has been known in which a gas generator is inserted from the outside of a furnace wall and capable of decomposing various raw material gases such as hydrocarbon gases in a reaction vessel containing a catalyst to obtain various decomposition gases.

[0003] In recent years, as shown in Patent Documents 2 and 3, a hydrogen generating apparatus and a method for using the same have become known, in which a raw material gas containing ammonia is decomposed in a reaction chamber to generate a gas containing hydrogen gas and nitrogen gas.

[0004] Here, Patent Documents 2 and 3 mentioned above disclose that the hydrogen gas obtained by decomposing a raw material gas containing ammonia in a reaction chamber as mentioned above is used in a fuel cell or the like.

[0005] However, Patent Documents 2 and 3 do not disclose at all that a gas containing hydrogen gas and nitrogen gas obtained by decomposing a raw material gas containing ammonia in a reaction chamber as described above is supplied into a furnace, and a workpiece such as a steel material is nitrided in the furnace.

[0006] In addition, conventionally, there is a nitriding apparatus in which ammonia gas is supplied into a furnace and a workpiece such as a steel material is nitrided by the ammonia gas in the furnace, and it is known that the furnace temperature is generally set to 500 to 600°C.

[0007] In such a nitriding apparatus, in order to control the state in which the workpiece, such as steel, is nitrided with ammonia gas, appropriate amounts of hydrogen gas and nitrogen gas are supplied to the furnace in addition to ammonia gas.

[0008] However, when using a catalyst to generate hydrogen gas or nitrogen gas to be supplied into the furnace, the temperature of the generated hydrogen gas or nitrogen gas becomes higher than the temperature suitable for nitriding, so the hydrogen gas or nitrogen gas must be cooled to approximately room temperature and then reheated in the furnace. This requires the installation of a temperature control device such as a cooling device, making it impossible to make the system compact, and space is required for various other equipment such as piping equipment, resulting in high equipment costs and high running costs. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Japanese Utility Model Application Publication No. 63-149229 [Patent Document 2] Patent No. 4267325 [Patent Document 3] Patent No. 5068707 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0010] The present invention aims to solve the above-mentioned problems in a gas generator that decomposes a raw material gas containing ammonia in a reaction vessel containing a catalyst to generate a gas containing hydrogen gas and nitrogen gas, and in a nitriding apparatus that nitrides a workpiece in a furnace with ammonia gas at a temperature of 500 to 600°C.

[0011] That is, the present invention provides a small-sized gas generating device that generates a gas containing hydrogen gas and nitrogen gas by decomposing a raw material gas containing ammonia in a reaction vessel at a low temperature, and also aims to reduce the installation space and reduce the equipment costs and running costs when, in the nitriding device as described above, the raw material gas containing ammonia is decomposed in a reaction vessel containing a catalyst, and the gas containing hydrogen gas and nitrogen gas is supplied into a furnace, and steel or other workpieces are nitrided in the furnace. [Means for solving the problem]

[0012] In order to solve the above-mentioned problems, the gas generator according to the present invention decomposes a source gas containing ammonia in a reaction vessel containing a catalyst to generate a gas containing hydrogen gas and nitrogen gas, and uses a catalyst that decomposes the source gas containing ammonia at a temperature of 500 to 600° C. Here, ruthenium can be used as the catalyst that can be activated at a temperature of 500 to 600° C.

[0013] By using a catalyst capable of decomposing ammonia-containing raw material gas at a temperature of 500 to 600°C to generate a gas containing hydrogen gas and nitrogen gas, a cooling device is not required, and a simple structure such as a small cartridge-type reaction vessel inserted into the furnace wall can be used to convert ammonia-containing raw material gas into a gas containing hydrogen gas and nitrogen gas at a temperature suitable for nitriding and generate the gas.

[0014] Furthermore, in order to solve the above-mentioned problems, the nitriding apparatus according to the present invention supplies ammonia gas from an ammonia inlet pipe into a furnace, and nitrides the workpiece in the furnace with the ammonia gas at a temperature of 500 to 600°C. In this nitriding apparatus, a reaction vessel containing a catalyst for decomposing ammonia-containing raw material gas is inserted into the furnace, and a gas containing hydrogen gas and nitrogen gas obtained by decomposing the ammonia-containing raw material gas in the reaction vessel is supplied into the furnace.

[0015] As in the nitriding apparatus of the present invention, a reaction vessel containing a catalyst that decomposes ammonia-containing raw material gas is inserted into a furnace, and the raw material gas containing ammonia is decomposed in the reaction vessel to produce a gas containing hydrogen gas and nitrogen gas, which is then supplied into the furnace. This eliminates the need to provide separate piping for supplying the hydrogen gas and nitrogen gas obtained by decomposing the ammonia-containing raw material gas into the furnace, thereby reducing installation space and equipment costs.

[0016] Furthermore, in the nitriding apparatus according to the present invention, it is preferable to use, as the catalyst contained in the reaction vessel, a catalyst that decomposes ammonia-containing raw material gas at a temperature of 500 to 600° C. In this way, when a catalyst that decomposes ammonia-containing raw material gas at a temperature of 500 to 600° C. is used to decompose the ammonia-containing raw material gas, the temperature of the gas containing hydrogen gas and nitrogen gas decomposed by the catalyst becomes a temperature of 500 to 600° C., and various equipment such as a temperature control device such as a cooling device that controls the temperature of the gas containing hydrogen gas and nitrogen gas obtained by decomposing the ammonia-containing raw material gas to a temperature corresponding to the temperature inside the furnace in which the workpiece is nitrided with ammonia gas is not required, thereby reducing installation space and equipment costs as well as running costs.

[0017] As described above, ruthenium, for example, can be used as a catalyst for decomposing the raw material gas containing ammonia at a temperature of 500 to 600°C.

[0018] Furthermore, in the nitriding apparatus according to the present invention, a concentration detection sensor is provided for detecting the concentration of hydrogen gas in the furnace, and the result detected by the concentration detection sensor is output to a control device, which controls the amount of ammonia gas supplied into the furnace through the ammonia inlet pipe and the amount of ammonia-containing raw material gas supplied to the reaction vessel. In this way, the concentration of ammonia gas in the furnace can be controlled, and the conditions for nitriding the workpiece, such as steel, can be appropriately adjusted according to each purpose. [Effects of the Invention]

[0019] In the gas generator according to the present invention, a source gas containing ammonia is decomposed in a reaction vessel containing a catalyst to generate a gas containing hydrogen gas and nitrogen gas. The catalyst used is a catalyst that decomposes the source gas containing ammonia at a temperature of 500 to 600°C. This allows the source gas containing ammonia to be decomposed in the reaction vessel at a low temperature to generate a gas containing hydrogen gas and nitrogen gas. Therefore, compared to the conventional method of decomposing a source gas containing ammonia at a temperature higher than 600°C, cooling it, and reheating it to a temperature suitable for nitriding, a gas containing hydrogen gas and nitrogen gas at a temperature suitable for nitriding can be obtained in one go. This eliminates the need for reheating the hydrogen gas and nitrogen gas, and also eliminates the need for a cooling device (temperature control device). This also allows for a compact cartridge-type generator that can be loaded from outside the furnace wall. Note that 500 to 600°C is a typical temperature suitable for nitriding, and is not limited to this range as long as it is suitable for nitriding.

[0020] Furthermore, in the nitriding apparatus according to the present invention, ammonia gas is supplied into a furnace from an ammonia inlet pipe, and the workpiece is nitrided in the furnace with the ammonia gas at a temperature of 500 to 600°C. A reaction vessel containing a catalyst that decomposes ammonia-containing raw material gas is inserted into the furnace, and a gas containing hydrogen gas and nitrogen gas obtained by decomposing the ammonia-containing raw material gas in the reaction vessel is supplied into the furnace. This eliminates the need to provide separate piping for supplying the hydrogen gas and nitrogen gas obtained by decomposing the ammonia-containing raw material gas into the furnace, thereby reducing installation space and equipment costs.

[0021] Furthermore, in the nitriding apparatus, if a catalyst such as ruthenium that decomposes ammonia-containing raw material gas at a temperature of 500 to 600°C is used as the catalyst contained in the reaction vessel, the temperature of the gas containing hydrogen gas and nitrogen gas obtained by decomposing the ammonia-containing raw material gas with the catalyst will be 500 to 600°C, and various equipment such as a temperature control device such as a cooling device or reheating device that controls the temperature of the gas containing hydrogen gas and nitrogen gas obtained by decomposing the ammonia-containing raw material gas to a temperature corresponding to the temperature inside the furnace in order to match the temperature inside the furnace in which the workpiece is nitrided with ammonia gas becomes unnecessary, thereby reducing installation space and equipment costs as well as running costs. [Brief explanation of the drawings]

[0022] [Figure 1] 1 is a schematic cross-sectional view illustrating an example of a gas generator according to a first embodiment of the present invention. [Figure 2] FIG. 10 is a schematic cross-sectional view illustrating an example of a nitriding device according to a second embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

[0023] The gas generating apparatus and nitriding apparatus according to the embodiments of the present invention will be specifically described below with reference to the accompanying drawings. The gas generating apparatus and nitriding apparatus according to the present invention are not limited to the embodiments shown below, and can be modified as appropriate within the scope of the invention.

[0024] (Embodiment 1) In the gas generator according to the first embodiment of the present invention, as shown in FIG. 1, ammonia gas NH3 is used as the raw material gas, and the ammonia gas NH3 is supplied to a reaction vessel 10 through a gas guide pipe p1.

[0025] Further, a catalyst containing section 11 containing a catalyst x that decomposes ammonia gas NH3 at a temperature of 500 to 600°C is provided in the reaction vessel 10, and a heating device 12 is provided around the catalyst containing section 11.

[0026] Here, in the gas generating apparatus of embodiment 1, ruthenium is used as the catalyst x, the catalyst x is heated to a temperature of 500 to 600°C by the heating device 12, ammonia gas NH3 supplied to the reaction vessel 10 by the gas guide pipe p1 is led into the catalyst containing section 11, and the ammonia gas NH3 is decomposed into hydrogen gas H2 and nitrogen gas N2 by the catalyst x contained in the catalyst containing section 11.

[0027] The hydrogen gas H2 and nitrogen gas N2 obtained by decomposing the ammonia gas NH3 are then discharged from the catalyst containing section 11 through the discharge port p2.

[0028] Here, in the gas generating device of embodiment 1, ruthenium is used as the catalyst x as described above, so that ammonia gas NH3 can be heated to a temperature of 500 to 600°C in the catalyst containing section 11 and decomposed into hydrogen gas H2 and nitrogen gas N2, and ammonia gas NH3 can be decomposed at a low temperature of 500 to 600°C to generate hydrogen gas H2 and nitrogen gas N2.

[0029] (Embodiment 2) In the nitriding apparatus according to the second embodiment of the present invention, an ammonia introduction pipe 21 is inserted into a furnace 20, and ammonia gas NH 3 is supplied from this ammonia introduction pipe 21 into the furnace 20, as shown in FIG.

[0030] In addition, in the nitriding apparatus according to the second embodiment, a reaction vessel 10 containing a catalyst x for decomposing ammonia gas NH3 is inserted into a furnace 20, and a gas containing hydrogen gas H2 and nitrogen gas N2 obtained by decomposing ammonia gas NH3 in the reaction vessel 10 is directly supplied into the furnace 20.

[0031] Here, as in the first embodiment, the reaction vessel 10 is provided with a catalyst containing section 11 containing ruthenium as a catalyst x for decomposing ammonia gas NH3 at a temperature of 500 to 600°C, and a heating device 12 is provided around the catalyst containing section 11.

[0032] Similarly to the first embodiment, ruthenium is used as the catalyst x, and the catalyst x is heated to a temperature of 500 to 600°C by the heating device 12. Ammonia gas NH3 supplied to the reaction vessel 10 through the gas guide pipe p1 is introduced into the catalyst containing section 11, and the ammonia gas NH3 is decomposed into hydrogen gas H2 and nitrogen gas N2 by the catalyst x contained in the catalyst containing section 11. The hydrogen gas H2 and nitrogen gas N2 thus decomposed at a temperature of 500 to 600°C are directly supplied from the reaction vessel 10 into the furnace 20.

[0033] In addition, in the nitriding apparatus of embodiment 2, a plurality of furnace heating devices 22 and fans 23 are provided in the furnace 20, and the furnace 20 is heated by the furnace heating devices 22, and the temperature inside the furnace 20 is raised to 500 to 600°C by the fans 23, so that the workpiece (not shown), such as steel, is nitrided.

[0034] Here, in the nitriding apparatus of embodiment 2, the hydrogen gas H2 and nitrogen gas N2 decomposed at a temperature of 500 to 600°C in the catalyst containing section 11 as described above are supplied directly from the reaction vessel 10 into the furnace 20. Therefore, when supplying the hydrogen gas H2 and nitrogen gas N2 from the reaction vessel 10 into the furnace 20, there is no need to separately install a temperature control device such as a cooling device that adjusts the temperature of these gases to the temperature inside the furnace 20 of 500 to 600°C, or piping for guiding these gases into the furnace 20. This significantly reduces the installation space and equipment costs, as well as the running costs.

[0035] Moreover, in the nitriding apparatus according to the second embodiment, the reaction vessel 10 is inserted into the furnace 20, and therefore the catalyst x in the catalyst containing section 11 of the reaction vessel 10 can be efficiently and quickly heated to 500 to 600°C by the temperature in the furnace 20. Furthermore, since the reaction vessel 10 is inserted into the furnace 20, heat radiation from the reaction vessel 10 is also reduced.

[0036] In addition, in the nitriding apparatus of embodiment 2, a concentration detection sensor 24 is provided to detect the concentration of hydrogen gas H2 in the furnace 20, and the concentration of hydrogen gas H2 detected by this concentration detection sensor 24 is output to the control device 25.

[0037] Further, the gas guide pipe p1 for supplying ammonia gas NH3 to the reaction vessel 10 is provided with a first control valve v1 for controlling the amount of ammonia gas NH3 to be supplied to the reaction vessel 10, and the second gas guide pipe p3 for supplying ammonia gas NH3 to the ammonia introduction pipe 21 is provided with a second control valve v2 for controlling the amount of ammonia gas NH3 to be supplied into the furnace 20 through the ammonia introduction pipe 21.

[0038] In the nitriding apparatus according to the second embodiment, the first control valve v1 and the second control valve v2 are controlled by the control device 25 based on the concentration of hydrogen gas H2 in the furnace 20 detected by the concentration detection sensor 24 and output to the control device 25.

[0039] Here, in the nitriding apparatus according to the second embodiment, the control device 25 controls the first control valve v1 to adjust the amount of ammonia gas NH3 supplied to the reaction vessel 10, and controls the amount of hydrogen gas H2 and nitrogen gas N2 decomposed in the catalyst containing section 11 that is supplied directly from the reaction vessel 10 into the furnace 20, while controlling the second control valve v2 to control the amount of ammonia gas NH3 supplied into the furnace 20 through the ammonia introduction pipe 21, thereby adjusting the concentration of hydrogen gas H2 in the furnace 20.

[0040] In this way, the concentration of hydrogen gas H2 in the furnace 20 can be appropriately controlled, and the conditions for nitriding the workpiece, such as steel, can be appropriately adjusted according to the purpose of nitriding the workpiece, and it is also possible to soft-nitridize the workpiece, such as steel. [Explanation of symbols]

[0041] 10: Reaction vessel 11: Catalyst housing section 12:Heating device 20: Furnace 21: Ammonia inlet pipe 22:Furnace heating device 23: Fan 24: Concentration detection sensor 25: Control device H2: Hydrogen gas N2: Nitrogen gas NH3: Ammonia gas p1: Gas guide pipe p2 :Exhaust port p3: Second gas guide pipe v1: First control valve v2: Second control valve x :Catalyst

Claims

1. A gas generator that generates a gas containing hydrogen gas and nitrogen gas by decomposing a source gas containing ammonia in a reaction vessel containing a catalyst, wherein the catalyst used is a catalyst that decomposes the source gas containing ammonia at a temperature of 500 to 600°C.

2. A nitriding apparatus in which ammonia gas is supplied into a furnace from an ammonia inlet pipe and an object to be treated is nitrided in the furnace with the ammonia gas at a temperature of 500 to 600°C, characterized in that a reaction vessel containing a catalyst for decomposing a raw material gas containing ammonia is inserted into the furnace, and a gas containing hydrogen gas and nitrogen gas obtained by decomposing the raw material gas containing ammonia in the reaction vessel is supplied into the furnace.

3. 3. The nitriding apparatus according to claim 2, wherein the catalyst contained in the reaction vessel is a catalyst that decomposes a raw material gas containing ammonia at a temperature of 500 to 600°C.

4. 3. The nitriding apparatus according to claim 2, wherein ruthenium is used as the catalyst contained in said reaction vessel.

5. The nitriding apparatus according to any one of claims 2 to 4, further comprising a concentration detection sensor for detecting the concentration of hydrogen gas in the furnace, the result detected by the concentration detection sensor being output to a control device, and the control device controlling the amount of ammonia gas to be supplied into the furnace through the ammonia inlet pipe and the amount of raw material gas containing ammonia to be supplied to the reaction vessel.

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