JP6975625B2 - Acetylene gas supply device for vacuum carburizing furnace and its supply method - Google Patents

Description

The present invention relates to an acetylene gas supply device for a vacuum carburizing furnace and a method for supplying the same.

In the vacuum carburizing treatment, a steel material is installed in the heat treatment furnace, a hydrocarbon gas such as acetylene is supplied into the heat treatment furnace in which the pressure is reduced in a vacuum, and carbon is applied to the surface of the steel material by applying heat of about 1000 ° C. It is a process of invading and hardening. Patent Document 1 and Patent Document 2 disclose an example of a technique relating to such vacuum carburizing.

FIG. 2 is a diagram showing a conventional general schematic apparatus configuration for realizing such a vacuum carburizing treatment. In FIG. 2, an acetylene gas supply device 100 for a vacuum carburizing furnace that supplies acetylene gas via an acetylene supply line 16 is connected to a vacuum carburizing furnace 200 in which a vacuum carburizing treatment is performed. Further, the acetylene gas supply device 100 for a vacuum carbonization furnace includes an acetylene cylinder (acetylene container) 11 in which acetylene gas is sealed, a pressure reducing valve 12 for adjusting the pressure, and an acetylene intervening in the middle of the acetylene supply line 16. It is composed of a mass flow controller (MFC: Mass Flow Controller) (hereinafter, referred to as “MFC”) 15 that controls the mass flow rate of gas.

By the way, not only the acetylene gas used for the vacuum carburizing treatment but also the acetylene gas used for other uses is often required to have high purity. Therefore, when supplying high-purity acetylene gas, a step or apparatus for removing impurities when producing the acetylene gas is internally or separately configured.

For example, Patent Document 3 relates to a technique for increasing the purity of lower unsaturated hydrocarbons such as acetylene, and pays attention to the difference in adsorption activity between impurities and lower unsaturated hydrocarbons, and uses an adsorbent to remove impurities. Techniques for removal are disclosed.

Further, Patent Document 4 generates lithium carbide from metallic lithium and carbon powder without using a chlorine compound-based cleaning agent, and reacts the lithium carbonate with water to generate crude acetylene gas, which is the crude acetylene gas. Discloses a technique for obtaining high-purity acetylene gas by contacting with a molecular sieve adsorbent.

Further, Patent Document 5 uses a dry adsorbent such as activated carbon or molecular sieves to remove water from the generated acetylene gas, and further uses a dry adsorbent such as activated alumina to remove hydride impurities from the gas after water removal. Discloses a technique for supplying high-purity acetylene produced by removing the above-mentioned material to a gas destination at a pressure of atmospheric pressure or less.

Japanese Unexamined Patent Publication No. 08-325701 Japanese Unexamined Patent Publication No. 2002-194526 Japanese Unexamined Patent Publication No. 62-045543 Japanese Unexamined Patent Publication No. 02-256626 Japanese Unexamined Patent Publication No. 2011-26205 Japanese Unexamined Patent Publication No. 62-019539 Japanese Unexamined Patent Publication No. 2004-148257

By the way, the inside of the acetylene cylinder 11 shown in FIG. 2 is composed of a porous mass, a solvent absorbed by the porous mass, and an acetylene gas dissolved in the solvent according to the pressure. Further, the solvent typically includes both or one of acetone and N, N-dimethylformamide (DMF: dimethylformamide) (hereinafter referred to as “DMF”).

Here, if the pressure in the acetylene cylinder 11 decreases with the use of the acetylene gas, the supplied acetylene gas may contain a solvent component accordingly. However, in vacuum carburizing treatment, these may inhibit carburizing, so acetylene gas having the highest possible purity is required.

Techniques for removing such a solvent are disclosed in, for example, Patent Documents 6 and 7.
In Patent Document 6, acetylene absorbed in a solvent having a temperature of -20 to -81.8 ° C. is heated to −10 to + 20 ° C. to dissipate acetylene, and the released acetylene is -50 to −81. It discloses the purification of high-purity acetylene by recooling to 8.8 ° C to remove the solvent and its condensates.

However, the technique in this document is only a technique for producing acetylene, and there is no viewpoint of pressure drop when using acetylene filled in a container. Therefore, the place where acetylene gas is used (particularly, vacuum). In a carburizing furnace), there is no problem of maintaining high purity.

Patent Document 7 discloses an apparatus in which an acetylene supply apparatus is portable so as to be able to generate high-purity acetylene gas at a place where acetylene is used, and more specifically, at the outlet of an acetylene container. It is provided downstream of the pressure reducing valve and is provided with an activated carbon column for removing a solvent, and a molecular sieves column provided downstream of the activated carbon column for removing water and a trace amount of residual gas. Furthermore, before the start of supply of ultra-high-purity acetylene to the place of use, a certain amount of acetylene containing air component impurities remaining in the upper gas phase of the high-purity dissolved acetylene container is discharged from the purge valve to the place of use. The purity of the supplied ultra-high purity acetylene is maintained.

However, the method of removing the solvent using an activated carbon column or the above-mentioned adsorbent has a high removal capacity, but the configuration is complicated, and it is a necessary configuration when making carbon-based materials such as carbon nanotubes. It was not suitable for acetylene to be supplied to the vacuum carburizing furnace.

Further, conventionally, when 5N acetylene gas is obtained, there is a problem that the purification efficiency of the gas is low and the practicality is limited due to the extremely high cost. Moreover, in general, high-purity acetylene cylinders on the market are very expensive and unsuitable for industrial use.

On the other hand, an apparatus configuration capable of parallelly interposing on the acetylene supply line 16 between the above-mentioned acetylene cylinder 11 and the vacuum carburizing furnace 200 is preferable.

The present invention has been made in view of the above circumstances, and is capable of supplying high-purity acetylene gas to a vacuum carburizing furnace with a simple and inexpensive configuration regardless of the gas supply pressure of the acetylene container. An object of the present invention is to provide an acetylene gas supply device for a furnace and a method for supplying the same.

In order to solve the above problems, the present invention has the following configurations.
[1] An acetylene gas supply device for a vacuum carburizing furnace that supplies acetylene gas to the vacuum carburizing furnace.
An acetylene container filled with acetylene dissolved in a solvent,
An acetylene supply path for supplying acetylene gas from the acetylene container to the vacuum carburizing furnace, and
A heat exchanger provided in the acetylene supply path to reliquefy the solvent component contained in the acetylene gas.
An acetylene gas for a vacuum carburizing furnace provided in the acetylene supply path on the secondary side of the heat exchanger and comprising a gas-liquid separator for separating the reliquefied solvent and the acetylene gas from which the solvent component has been removed. Feeding device.
[2] The heat exchanger reliquefies the solvent component contained in the acetylene gas by cooling the acetylene gas from the acetylene container to a temperature lower than the boiling point of the solvent, in [1]. The acetylene gas supply device for the vacuum carburizing furnace described.
[3] The acetylene gas supply device for a vacuum carburizing furnace according to [1] or [2], wherein the solvent contains at least one of acetone and N, N-dimethylformamide.
[4] The acetylene gas supply device for a vacuum carburizing furnace according to any one of [1] to [3], wherein the heat exchanger is a fin tube type heat exchanger.
[5] The acetylene gas supply device for a vacuum carburizing furnace according to any one of [1] to [4], wherein the gas-liquid separator is a centrifugal gas-liquid separator.
[6] An acetylene gas supply method for a vacuum carburizing furnace, which supplies acetylene gas to the vacuum carburizing furnace via an acetylene supply path.
The solvent component contained in the acetylene gas is reliquefied by using a heat exchanger with the acetylene gas derived from the acetylene container filled with acetylene dissolved in the solvent.
A vacuum carburizing furnace that separates the reliquefied solvent from the acetylene gas from which the solvent component has been removed by a gas-liquid separator downstream of the heat exchanger, and then supplies the acetylene gas to the vacuum carburizing furnace. For acetylene gas supply method.

According to the acetylene gas supply device for a vacuum carburizing furnace and the supply method thereof of the present invention, a simple and inexpensive configuration in which a heat exchanger and a gas-liquid separator are interposed is high regardless of the gas supply pressure of the acetylene container. Pure acetylene gas can be supplied to the vacuum carburizing furnace.

FIG. 1 is a diagram showing an apparatus configuration of an embodiment of the acetylene gas supply apparatus for a vacuum carburizing furnace and the supply method thereof of the present invention. FIG. 2 is a diagram for explaining the prior art.

Hereinafter, the configuration of the acetylene gas supply device for a vacuum carburizing furnace, which is an embodiment to which the present invention is applied, will be described in detail with reference to the supply method. In addition, in the drawings used in the following explanation, in order to make the features easy to understand, the featured parts may be enlarged for convenience, and the dimensional ratios of each component may not be the same as the actual ones. No.

FIG. 1 is a diagram showing an apparatus configuration of an embodiment of the acetylene gas supply apparatus for a vacuum carburizing furnace and the supply method thereof of the present invention.
As shown in FIG. 1, the acetylene gas supply device 1 for a vacuum carburizing furnace is a device for supplying high-purity acetylene gas to the vacuum carburizing furnace 200 via an acetylene supply line (acetylene supply path) 16. .. The acetylene gas supply device 1 for a vacuum carbonization furnace includes an acetylene cylinder (acetylene container) 11, a pressure reducing valve 12 arranged in order from the upstream on the acetylene supply line 16, and a fin tube type heat exchange including an on-off valve. It is composed of a vessel (heat exchanger) 13, a centrifugal gas-liquid separator (gas-liquid separator) 14 including an on-off valve, and an MFC 15.

The inside of the acetylene cylinder 11 is composed of a porous mass, a solvent absorbed by the porous mass, and an acetylene gas dissolved in the solvent according to the pressure. Here, in the present embodiment, the case where both acetone and DMF are used as the solvent to be absorbed by the porous mass will be described as an example. The solvent is not particularly limited as long as it can dissolve acetylene gas, but a solvent containing at least one of acetone and DMF is preferable. The boiling points of acetone and DMF are 56 ° C and 153 ° C, respectively.

The cooling temperature of the fin tube type heat exchanger 13 is set to 15 to 40 ° C. by controlling the cooling water to be introduced, and when the acetylene gas supplied from the acetylene cylinder 11 is passed through the fin tube type heat exchanger 13, it is included in the acetylene gas. Both the solvent components, that is, acetone and DMF, are condensed.

The liquefied solvent generated by the fin tube heat exchanger 13 and the acetylene gas from which the solvent component has been removed are sent to the centrifugal gas-liquid separator 14. In the centrifugal gas-liquid separator 14, the solvent as a liquid is accumulated in the lower part, and the upper part is filled with acetylene gas from which the solvent component has been removed. Here, the liquefied solvent is led out to the outside via the on-off valve, and the acetylene gas is sent to the vacuum carburizing furnace 200 via the MFC 15. The MFC 15 is for controlling the mass flow rate of acetylene gas.

In the above-described embodiment, the configuration in which the fin tube type heat exchanger 13 is adopted as the heat exchanger for cooling the acetylene gas supplied from the acetylene cylinder 11 has been described as an example, but the present invention is not limited to this. .. Other heat exchangers may be used as long as the solvent component contained in the acetylene gas can be reliquefied by cooling to a temperature lower than the boiling point of the solvent contained in the acetylene gas. In particular, if a solvent having a high boiling point such as acetone or DMF is used in the acetylene cylinder 11, the range of heat exchangers that can be adopted is expanded because they are liquids at room temperature.

Further, in the above-described embodiment, a configuration in which a centrifugal gas-liquid separator is used as a device for separating the liquefied solvent and the acetylene gas from which the solvent component has been removed has been described as an example, but the present invention is limited to this. There is no such thing. Other gas-liquid separators may be used as long as they can separate the liquefied solvent and the acetylene gas from which the solvent component has been removed.

As described above, according to the above-described embodiment, the acetylene cylinder 11 has a simple and inexpensive configuration in which the fin tube heat exchanger 13 and the centrifugal gas-liquid separator 14 are interposed in the acetylene supply line 16. High-purity acetylene gas can be supplied to the vacuum carburizing furnace 200 regardless of the gas supply pressure. In particular, as described above, when acetone and DMF are used as the solvent, the cooling temperature in the fin tube heat exchanger 13 can be set to 15 to 40 ° C. near room temperature.

The acetylene gas supply device for a vacuum carburizing furnace and the method for supplying the acetylene gas for a vacuum carburizing furnace of the present invention can be adopted, for example, in the case of supplying acetylene gas for vacuum carburizing treatment to the vacuum carburizing furnace.

1 ... Acetylene gas supply device for vacuum carburizing furnace, 11 ... Acetylene bomb (acetylene container), 12 ... Pressure reducing valve, 13 ... Fin tube heat exchanger (heat exchanger), 14 ... Centrifugal gas-liquid separator (gas) Liquid separator), 15 ... MFC, 16 ... acetylene supply line (acetylene supply path), 100 ... acetylene gas supply device for vacuum carburizing furnace, 200 ... vacuum carburizing furnace

Claims (4)

An acetylene gas supply device for a vacuum carburizing furnace that supplies acetylene gas to a vacuum carburizing furnace.
An acetylene container filled with acetylene dissolved in a solvent,
An acetylene supply path for supplying acetylene gas from the acetylene container to the vacuum carburizing furnace, and
A pressure reducing valve provided in the acetylene supply path and adjusting the pressure of the acetylene gas,
A fin tube heat exchanger provided in the acetylene supply path, which reliquefies the solvent component contained in the acetylene gas, introduces cooling water and cools the temperature to 15 to 40 ° C.
A vacuum carburizing furnace provided in the acetylene supply path on the secondary side of the heat exchanger and provided with a centrifugal gas-liquid separator for separating the reliquefied solvent and the acetylene gas from which the solvent component has been removed. For acetylene gas supply device. The vacuum according to claim 1, wherein the heat exchanger reliquefies the solvent component contained in the acetylene gas by cooling the acetylene gas from the acetylene container to a temperature lower than the boiling point of the solvent. Acetylene gas supply device for carburizing furnace. The acetylene gas supply device for a vacuum carburizing furnace according to claim 1 or 2, wherein the solvent contains at least one of acetone and N, N-dimethylformamide. It is an acetylene gas supply method for a vacuum carburizing furnace that supplies acetylene gas to a vacuum carburizing furnace via an acetylene supply path.
The acetylene gas, which is derived from an acetylene container filled with acetylene dissolved in a solvent and whose pressure is adjusted by a pressure reducing valve, is cooled to 15 to 40 ° C. by introducing cooling water. Reliquefies the solvent component contained in the gas and reliquefies it.
After separating the reliquefied solvent and the acetylene gas from which the solvent component has been removed by a centrifugal gas-liquid separator downstream of the heat exchanger, the acetylene gas is supplied to the vacuum carburizing furnace. Acetylene gas supply method for vacuum carburizing furnace.

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