JP5694633B2 - Gas replacement method in piping and gas replacement device in piping - Google Patents

Description

  The present invention relates to a gas replacement method in a pipe in which air is blown into the pipe and the gas staying in the pipe is replaced with air.

  In order to prevent gas poisoning, fire, and gas explosion, gas transport piping that transports by-product gas such as blast furnace gas generated at steelworks usually performs internal inspection work during periodic inspection work and repair work. After replacing the gas in the piping with nitrogen gas, which is an inert gas, the nitrogen gas is replaced with air (see, for example, Patent Document 1).

  FIG. 3 is a diagram schematically showing a part of a general blast furnace gas transport piping system. A U-shaped water sealing valve (U-shaped water sealing pipe) 2 is provided at both ends of the blast furnace gas transport pipe 1, and a replacement gas blowing pipe 3 is connected near one end of the blast furnace gas transport pipe 1, near the other end. A gas diffusion tube 5 is connected to the gas pipe. An on-off valve 4 is provided at the upper end of the replacement gas blowing pipe 3, and a bleeder valve 6 is provided at the upper end of the gas diffusion pipe 5.

When replacing the blast furnace gas staying in the blast furnace gas transport pipe 1 with air, the blast furnace gas is discharged from the gas diffusion pipe 5 while sending nitrogen gas into the blast furnace gas transport pipe 1 using the replacement gas blowing pipe 3. . When the blast furnace gas concentration in the blast furnace gas transport pipe 1 becomes a predetermined value or less, the supply of nitrogen gas is stopped, and an air supply pipe (not shown) is connected to the replacement gas blowing pipe 3 to transport the blast furnace gas. While blowing air into the pipe 1, nitrogen gas is discharged from the gas diffusion pipe 5, and the gas in the blast furnace gas transport pipe 1 is replaced with air.

The diameter of the blast furnace gas transport pipe 1 is, for example, 4200 A, and the air replacement range L is, for example, 900 m.
JP 2007-024271 A

  As described above, when performing the operation of replacing the blast furnace gas in the blast furnace gas transport pipe 1 with air, the air supply pipe is connected to the replacement gas blow pipe 3 to blow air into the blast furnace gas transport pipe 1. Yes. Therefore, the amount of air blown into the blast furnace gas transport pipe 1 is restricted by the size of the air supply pipe, and particularly when the blast furnace gas transport pipe 1 is a large-diameter pipe, a large amount is required until air replacement is completed. It took a long time. In addition, since air is compressed by the compressor and then blown into the blast furnace gas transport pipe 1, a pumping cost (air blowing power cost) is also incurred.

  The present invention has been made in view of the circumstances as described above, and when replacing the gas in the pipe with air, the gas replacement in the pipe can reduce the air replacement time and reduce the air blowing power. It is intended to provide a method.

  In order to solve the above problems, the present invention has the following features.

  [1] An air replacement ejector configured to suck the atmosphere by traction action of compressed air supplied from a compressed air supply pipe when the compressed air is blown into the pipe to replace the gas in the pipe with air. A method for replacing a gas in a pipe, wherein the atmosphere sucked in addition to the compressed air is blown into the pipe.

  In the present invention, the air replacement ejector that sucks the atmosphere by the traction action of the compressed air supplied from the compressed air supply pipe is used to blow the atmosphere into the pipe in addition to the compressed air. The amount of replacement air that is blown into the air increases, so that the air replacement time can be shortened and the air blowing power can be reduced.

  An embodiment of the present invention will be described with reference to the drawings. Here, a blast furnace gas transport pipe will be described as an example.

  FIG. 1 is a diagram schematically showing a blast furnace gas transport pipe in one embodiment of the present invention. Similar to FIG. 3 described above, U-shaped water sealing valves (U-shaped water sealing pipes) 2 are provided at both ends of the blast furnace gas transport pipe 1, and a replacement gas blowing pipe is provided near one end of the blast furnace gas transport pipe 1. 3 is connected, and the gas diffusion pipe 5 is connected in the vicinity of the other end. An on-off valve 4 is provided at the upper end of the replacement gas blowing pipe 3, and a bleeder valve 6 is provided at the upper end of the gas diffusion pipe 5.

  In addition, in this embodiment, when air is blown into the blast furnace gas transport pipe 1, as shown in FIG. 1, an air replacement ejector 10 is connected to the replacement gas blowing pipe 3 via the on-off valve 4. I am doing so.

  FIG. 2 shows the ejector 10 for air replacement. The air replacement ejector 10 has an upper end 11a opened to the atmosphere, and a lower end 11b penetrating the side of the air suction pipe 11 connected to the open / close valve 4 of the replacement gas blowing pipe 3, and the tip thereof. 12a opens in the suction pipe 11 toward the lower end 11b, and a rear end 12b is provided with a compressed air nozzle 12 connected to a compressed air supply pipe 15 from a compressor (not shown).

  In the air replacement ejector 10, when the compressed air supplied via the compressed air supply pipe 15 is ejected from the tip 12 a of the compressed air nozzle 12 into the atmospheric suction pipe 11, its traction action (eject effect). Thus, air is sucked from the upper end 11a of the air suction tube 11. Therefore, by using this air displacement ejector 10, in addition to the compressed air supplied via the compressed air supply pipe 15, the atmosphere sucked by the air displacement ejector 10 is combined with the blast furnace gas transport pipe 1. Can be blown into.

  Therefore, in this embodiment, when replacing the blast furnace gas staying in the blast furnace gas transport pipe 1 with air, the following procedure is performed.

  (S1) First, the blast furnace gas is discharged from the gas diffusion pipe 5 while sending nitrogen gas into the blast furnace gas transport pipe 1 using the replacement gas blowing pipe 3.

  (S2) When the blast furnace gas concentration in the blast furnace gas transport pipe 1 becomes a predetermined value or less, the supply of nitrogen gas is stopped, and the air replacement ejector 10 is attached to the replacement gas blowing pipe 3. In other words, the lower end 11b of the air suction pipe 11 of the air replacement ejector 10 is connected to the on-off valve 4 of the replacement gas blowing pipe 3, and the compressed air nozzle 12 of the air replacement ejector 10 is compressed to the rear end 12b of the compressor from the compressor. The air supply pipe 15 is connected.

  (S3) Then, in addition to the compressed air supplied via the compressed air supply pipe 15 using the air replacement ejector 10, the atmosphere sucked by the air replacement ejector 10 is combined with the blast furnace gas transport pipe 1. While blowing in, nitrogen gas is discharged from the gas diffusion pipe 5, and the gas in the blast furnace gas transport pipe 1 is replaced with air.

  Thus, in this embodiment, the air replacement ejector 10 that sucks the atmosphere by the traction action of the compressed air supplied from the compressed air supply pipe 15 is used to supply the compressed air through the compressed air supply pipe 15. In addition to the compressed air, the air sucked by the air replacement ejector 10 is blown into the blast furnace gas transport pipe 1 together, so the amount of replacement air blown into the blast furnace gas transport pipe 1 is As a result, the air replacement time can be shortened and the air blowing power can be reduced.

  In this embodiment, the blast furnace gas transport pipe has been described as an example, but the present invention can also be applied to other pipes.

  Examples of the present invention are described below.

As an example of the present invention, the blast furnace gas in the blast furnace gas transport pipe 1 was replaced with air based on the above-described embodiment of the present invention. For comparison, as a conventional example, the blast furnace gas in the blast furnace gas transport pipe 1 was replaced with air by a conventional method not using the air replacement ejector 10. The diameter of the blast furnace gas transport pipe 1 is 4400 A, and the air replacement range L is 900 m .

  As a result, in the example of the present invention, the air replacement time was reduced by 25% and the air blowing power was reduced by 30% compared to the conventional example.

  Thereby, the effectiveness of the present invention could be confirmed.

It is explanatory drawing of one Embodiment of this invention. It is explanatory drawing of the ejector for air replacement used by one Embodiment of this invention. It is explanatory drawing of a prior art.

Explanation of symbols

1 Blast furnace gas transport piping 2 U-shaped water sealing valve (U-shaped water sealing tube)
DESCRIPTION OF SYMBOLS 3 Replacement gas blowing pipe 4 On-off valve 5 Gas diffusion pipe 6 Breeder valve 10 Air displacement ejector 11 Atmospheric suction pipe 11a Upper end of atmospheric suction pipe 11b Lower end of atmospheric suction pipe 12 Compressed air nozzle 12a Compressed air nozzle tip 12b Compressed air nozzle Rear end 15 Compressed air supply pipe

Claims (4)

After replacing the gas in the pipe with inert gas, compressed air is blown into the pipe to discharge the inert gas in the pipe from the gas diffusion pipe provided at one end of the pipe and replace it with air. Using an air replacement ejector adapted to suck the atmosphere by the traction action of the compressed air supplied from the air supply pipe, in addition to the compressed air, suction is performed from the upper end of the air suction pipe of the air replacement ejector. the has been the atmosphere via a replacement gas blowing tube and the other end connected to the vicinity of the pipe, a gas replacement method of blowing write no distribution pipe in the pipe,
When the compressed air is blown into the pipe and the gas in the pipe is replaced with air, first, the replacement gas blowing pipe is used to feed the inert gas into the pipe from the gas diffusion pipe. When the gas concentration in the pipe falls below a predetermined value, the supply of the inert gas is stopped, the air replacement ejector is attached to the replacement gas blowing pipe, while blowing air sucked together with the compressed air, an inert gas discharged from the gas-effusing tube, distribution tube method gas replacement, characterized in that the gas in the pipe is replaced with air. 2. The gas replacement method in a pipe according to claim 1 , wherein the pipe is a blast furnace gas transport pipe, and the inert gas is nitrogen. The gas gas transport in the pipe a gas replacement device in the pipe to be replaced with air,
U-shaped water-sealed tubes provided at both ends of the piping;
A gas diffusion pipe provided at one end of the pipe, from which the gas in the pipe is released;
A replacement gas blowing pipe connected near the other end of the pipe,
Through the replacement gas inlet tube, after replacing the gas in the pipe by supplying an inert gas to the inert gas by the inert gas supply means to stop the supply of the inert gas, the replacing gas inlet tube A gas replacement device in a pipe, wherein an air replacement ejector is connected as an air supply means. The air replacement ejector includes a compressed air nozzle that penetrates the side surface of the atmospheric suction pipe, the front end of which opens toward the lower surface of the atmospheric suction pipe, and the rear end of which is connected to a compressed air supply pipe from the compressor. The gas replacement device in a pipe according to claim 3 , wherein

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