Pressurized welding repair and safety measures for

2022-08-09
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Pressure welding repair and safety measures for gas pipeline (coking plant) - advantages of using pressure direct welding repair (3)

pressure welding repair measures after local leakage of gas pipeline have the advantages of low risk, fast speed, small impact (not affecting normal production) and good effect. Its advantages are as follows:

1 There is no great impact on the production of the whole plant and the external supply of gas

using pressure welding repair, only the production scheduling department needs to reduce the pressure of the gas system by about 50% of the original normal pressure (Jiangsu Zhenjiang Coking Gas Group Company from 8000~10000pa to 4000~4500pa) about 10 minutes before the welding repair operation. At this time, the pipeline will maintain a certain positive pressure at the beginning of this year, and the production and gas transmission of the system will remain in normal operation

2. The speed of repairing leaking pipes is fast

the pipeline cracks are usually repaired by pressure welding. The welding repair can be completed in 20~30min for a short time, and 1~2h for a long time at most. Therefore, compared with other maintenance methods, there is no need to close multiple gate valves and insert several blind plates. Jin Min has successfully won orders from hundreds of customers and replaced them with steam, which saves many cumbersome operating procedures and reduces on-site workload. According to my experience and analysis, there are generally two cases of pipeline leakage. One is that the pipeline has long cracks and large openings. In this case, it is necessary to roll a semicircular crescent shaped hoop (close to the pipe diameter) with a steel plate with a thickness of 6~8mm and a width of about 150mm in advance according to the diameter and wall thickness of the pipe before welding repair, and open a small round opening at the lowest end of the hoop, weld a galvanized pipe head (equipped with a plug), and then weld the semicircular hoop at the gap of the pipe after the gas pressure is reduced. Hoop friction and wear tester introduces in detail that the function of the lower pipe head is to make the residual ammonia and a small amount of tar sundries in the gap of the leakage on the pipe be discharged regularly. Such repair welding under pressure can be carried out by two welders at the same time, and the welding time can be controlled within 1~1. Within 5h; Another situation is that the gap at the leakage of the pipe is small, and the weld is also short. At this time, for pressure welding repair, the surface sundries at the gap should be cleaned first, and then the gap should be welded directly. The operation time is often controlled at about 30min. If the leakage point of the pipeline is very small, it can be completed in only about 10min

3. Low risk

on the premise of strictly taking various on-site safety precautions and fully coordinating the production process and operation links, the use of pressure welding repair method has become increasingly mature, and the risk is also small. Under the condition of maintaining a small positive pressure, even if a small amount of open fire occurs when igniting the leaked gas during electric welding on the pipeline, it is normal and will not affect the normal gas transmission and welding repair progress. (Lei Xiaoming Yan 1's carbon dioxide emissions fell by 89% Haiquan)

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