Blast furnace gas main pipeline under-pressure plugging method

Abstract

The invention relates to a blast furnace gas main pipeline under-pressure plugging method, and belongs to the technical field of ferrous metallurgy in the metallurgical industry. According to the technical scheme, firstly, a small hole is formed in a point B in front of a leakage point C of the gas pipeline through a small tapping machine (1), and a balance pup joint (2) with a ball valve (10) is installed; secondly, opening a plugging hole at a point A before a point B of the gas pipeline by using a large tapping machine (3); thirdly, pushing a plugging head (14) and a rubber metal air bag (15) into the gas pipeline on the plugging hole by using a plugging machine (5); and fourthly, inflating the rubber metal air bag (15) to realize pressurized plugging of the gas pipeline, after the pressurized plugging of the gas pipeline, performing purging replacement on the gas pipeline behind the point B, and after the detection is qualified, using the point B as a monitoring point, and installing a gas detector (6) to perform real-time monitoring. The device has the beneficial effects that under the condition that blast furnace gas is not stopped, the gas is thoroughly cut off, and then the replacement and maintenance operation of the gas pipeline is completed.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of blast furnace gas main pipeline pressure plugging method, belong to metallurgical industry steel metallurgy technical field. BACKGROUND

[0002] During the operation of industrial gas pipeline, whether conveying any gas, in addition to planned maintenance and modification, more unavoidable emergency repair, such as pressure repair, replacement of corrosion pipe section, installation of device, sub-transmission modification and other operations.For pipeline repair, modification and other, the traditional construction method is to cut off the involved pipeline flow, depressurize, empty, purge and replace, and then implement the operation by hole opening method such as welding, sawing and drilling.The construction method is mature, but it must stop conveying and empty the pipeline before operation, or only temporary remedial measures can be taken, which brings great hidden danger to the safe operation of the pipeline and causes great economic loss.Especially for the main pipeline network of blast furnace gas, the loss caused by the need for all blast furnaces to blow down and shut down is immeasurable.

[0003] To avoid the significant loss caused by the overall shutdown of steel enterprises, the main pipeline of the main pipeline network of blast furnace gas is plugged under pressure and opened under pressure to completely block the gas and achieve safe construction conditions. SUMMARY

[0004] The purpose of the present application is to provide a method for plugging the main pipeline of blast furnace gas under pressure, which completely blocks the gas by using the plugging technology of opening under pressure, and then completes the replacement and repair of the gas pipeline, solving the problems in the background art.

[0005] The technical solution of the present application is: A method for plugging the main pipeline of blast furnace gas under pressure, which is operated according to the following steps: Step one: first weld a small tee at point B before the leakage point C of the gas pipeline, install a small stop valve on the small tee, install a small opening machine on the small stop valve, open a small hole with the small opening machine, install a balanced short circuit with a ball valve, then withdraw the small opening machine, close the small stop valve, and remove the small opening machine; Step two: weld a large tee at point A before point B of the gas pipeline, install a large stop valve on the large tee, install a large opening machine on the large stop valve, connect the large opening machine through the balanced short circuit and pressure equalizing pipe for pressure equalization, open the plugging hole with the large opening machine, complete the operation, withdraw the large opening machine, close the large stop valve, and remove the large opening machine; Step three: install a plugging machine on the plugging hole, open the large stop valve, connect the plugging machine through the balanced short circuit and pressure equalizing pipe for pressure equalization, and use the plugging machine to push the plugging head and rubber metal air bag into the gas pipeline; Step four: inflate the rubber metal air bag, realize the coal gas pipeline pressure sealing.

[0006] In the above-mentioned high pressure sealing method of the main pipeline of blast furnace gas, after the rubber metal air bag is inflated to realize the pressure sealing of the coal gas pipeline, the sealing machine is removed, nitrogen pipeline is connected to the balance short joint, the cut-off coal gas pipeline is purged and replaced, and the gas is released through the release pipe at the end of the coal gas pipeline.

[0007] In the above-mentioned high pressure sealing method of the main pipeline of blast furnace gas, after the coal gas pipeline is sealed under pressure, B point is used as a purging point to purge and replace the coal gas pipeline after B point. After the detection is qualified, B point is used as a monitoring point, and a gas detector is installed for real-time monitoring.

[0008] In the above-mentioned high pressure sealing method of the main pipeline of blast furnace gas, nitrogen is used for purging and replacement before the small opening machine, the large opening machine and the sealing machine are removed.

[0009] The beneficial effects of the present application are: avoiding the economic loss caused by the shutdown of blast furnace, eliminating the safety hazards of traditional pressure operation, especially the delivery pipeline of liquid or gaseous medium with large diameter, high pressure, flammable and explosive, toxic and harmful. BRIEF DESCRIPTION OF DRAWINGS

[0010] Figure 1 The figure shows the structure of the balance joint installed in the present application; Figure 2 The figure shows the structure of the pipeline opening and sealing hole operation in the present application; Figure 3 The figure shows the structure of the pipeline sealing operation in the present application; Figure 4 The figure shows the structure of the pipeline purging and detection in the present application; Figure 5 The figure shows the structure of the rubber metal air bag before blowing in the present application; Figure 6 The figure shows the structure of the rubber metal air bag after blowing in the present application; In the figure: small opening machine 1, balance short joint 2, large opening machine 3, sealing machine 4, pressure equalizing connecting pipe 5, gas detector 6, small plug valve 7, small tee joint 8, small drill bit 9, ball valve 10, large plug valve 11, large tee joint 12, large drill bit 13, sealing head 14, rubber metal air bag 15, release pipe 16, end isolation device 17, coal gas pipeline 18, pressure opening point A, short joint opening point B, coal gas pipeline leakage point C. DETAILED DESCRIPTION

[0011] The present application will be further described by examples in conjunction with the drawings.

[0012] Refer to the drawings Figures 1-6A method for plugging a blast furnace gas main pipe under pressure, which is operated according to the following steps: Step one: first weld a small tee 8 at point B before the leakage point C of the gas pipe, install a small stop valve 7 on the small tee 8, install a small opening machine 1 on the small stop valve 7, open a small hole by using the small opening machine 1, install a balance short connection 2 with a ball valve 10, then withdraw the small opening machine 1, close the small stop valve 7, and remove the small opening machine 1; Step two: weld a large tee 12 at point A before point B of the gas pipe, install a large stop valve 11 on the large tee 12, install a large opening machine 3 on the large stop valve 11, connect the large opening machine 3 through the balance short connection 2 and the pressure equalizing connection pipe 5 for pressure equalization, open the plugging hole by using the large opening machine 3, withdraw the large opening machine 3 after completion, close the large stop valve 11, and remove the large opening machine 3; Step three: install a plugging machine 4 on the plugging hole, open the large stop valve 11, connect the plugging machine 4 through the balance short connection 2 and the pressure equalizing connection pipe 5 for pressure equalization, and use the plugging machine 5 to push the plugging head 14 and the rubber metal air bag 15 into the gas pipe; Step four: inflate the rubber metal air bag 15 to achieve plugging of the gas pipe under pressure.

[0013] In this embodiment, the plugging of a DN4000 gas pipe is taken as an example, which is operated according to the following steps: Step one: first weld a small tee 8 at point B, install a small stop valve 7 on the small tee 8, install a small opening machine 1 on the small stop valve 7, open the small stop valve 7, and open a small hole with a diameter of 50 cm by using the small opening machine 1, install a balance short connection 2 with a diameter of 50 cm and a ball valve 10, withdraw the small opening machine 1 after completion, close the small stop valve 7, and remove the small opening machine 1, as shown in Figure 1 ; Step two: weld a large tee 12 at point A before point B of the gas pipe, install a large stop valve 11 on the large tee 12, install a large opening machine 3 on the large stop valve 11, connect the large opening machine 3 through the balance short connection 2 and the pressure equalizing connection pipe 5 for pressure equalization, push the large opening machine 3 to open the plugging hole by using a mobile hydraulic station, use nitrogen to purge and replace the large opening machine 3 after completion, withdraw the large opening machine 3, close the large stop valve 11, and remove the large opening machine 3, as shown in Figure 2 ; Step three: install a plugging machine 4 on the plugging hole, open the large stop valve 11, connect the plugging machine 4 through the balance short connection 2 and the pressure equalizing connection pipe 5 for pressure equalization, and use the plugging machine 5 to push the plugging head 14 and the rubber metal air bag 15 into the gas pipe by using a mobile hydraulic station, as shown in Figure 3 ; Step four: inflate the rubber metal air bag 15 to achieve plugging of the gas pipe under pressure, as shown in Figure 5 ,6 As shown; Step 5: After purging and replacing the sealing machine 4 with nitrogen, remove the sealing machine 4. Then, use a nitrogen pipeline connected to the balance short-circuit 2 to purge and replace the disconnected gas pipeline. Vent the gas using the vent pipe 9 at the end of the original gas pipeline, as shown in the attached diagram. Figure 4 As shown; Step Six: Using point B as the purging point, purge and replace the gas pipeline after point B. After passing the inspection, install monitoring instruments at point B as the monitoring point for real-time monitoring to ensure safety during the welding of blind flanges or modification work on the gas pipeline after it is cut off. (See attached document) Figure 4 As shown.

Claims

1. A method for pressurized sealing of a blast furnace gas main pipeline, characterized in that: Follow these steps: Step 1: First, weld a small tee (8) at point B before the gas pipeline leak point C. Install a small gate valve (7) on the small tee (8). Install a small hole punch (1) on the small gate valve (7). Use the small hole punch (1) to make a small hole and install a balance short circuit (2) with a ball valve (10). Then, remove the small hole punch (1), close the small gate valve (7), and remove the small hole punch (1). Step 2: Weld a large tee (12) at point A before point B of the gas pipeline, install a large gate valve (11) on the large tee (12), install a large hole punch (3) on the large gate valve (11), connect the large hole punch (3) through the balance short circuit (2) and the pressure equalization connection pipe (5) to equalize the pressure, use the large hole punch (3) to open the sealing hole, after completion, remove the large hole punch (3), close the large gate valve (11), and remove the large hole punch (3); Step 3: Install the sealing machine (4) on the sealing hole, open the large gate valve (11), connect the sealing machine (4) through the balance short circuit (2) and the pressure equalization connection pipe (5) to equalize the pressure, and use the sealing machine (5) to push the sealing head (14) and the rubber metal air bag (15) into the gas pipeline; Step 4: Inflate the rubber-metal airbag (15) to achieve pressurized sealing of the gas pipeline.

2. The method for pressurized sealing of a blast furnace gas main pipeline according to claim 1, characterized in that: After the rubber-metal airbag (15) is inflated to achieve pressurized sealing of the gas pipeline, the sealing machine (4) is removed, and the gas pipeline after being cut off is purged and replaced by connecting the nitrogen pipeline to the balance short connector (2), and then released through the gas pipeline end vent pipe (9).

3. A method for pressurized sealing of a blast furnace gas main pipeline according to claim 1 or 2, characterized in that: After the gas pipeline is sealed under pressure, point B is used as the purging point to purge and replace the gas pipeline after point B. After the test is qualified, point B is used as the monitoring point and a gas detector (6) is installed for real-time monitoring.

4. The method for pressurized sealing of a blast furnace gas main pipeline according to claim 1, characterized in that: Before dismantling the small hole punch (1), the large hole punch (3), and the sealing machine (4), nitrogen gas must be used for purging and replacement.

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