The 600,000-ton catalytic unit has numerous leakage points in the 35-kilogram steam line flanges
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This post was last edited by jbcyf on 2012-1-17 at 12:47. There are many leakage points in the 35-kilogram steam lines and medium-pressure deoxygenated water lines; the original design used octagonal steel gaskets. What is a good alternative for replacing these gaskets in order to reduce leakage? I seek advice from those who are more experienced.
Possible factors: 1. Insufficient consideration for piping expansion； 2. Quality issues with flange gaskets ； The piping can be reconfigured for adjustment. Or some are also welded directly with steel rings. For reference only!
Is it possible that the hardness of the octagonal pad is too high?
Eight-foot pads are very suitable for use in this application. It is likely that the sealing surfaces were not cleaned properly during installation, or that the flanges are severely corroded; there may also be issues such as uneven flange surfaces or inadequate thermal tightening. It’s not a gasket issue.
Using octagonal steel gaskets for the flanges of the 35-kilogram steam line and the medium-pressure deoxygenated water line is absolutely correct!
A wound gasket can also be used for a pressure of 35 kilograms.
If it is designed for steam at 3.5 MPa, then 4.5 MPa gaskets should be used; if there are many leakage points, it is recommended to replace them with male-and-female flanges during maintenance
I think it’s mainly caused by inadequate installation and the gaskets failing under the high temperature and pressure.
1. During installation, the debris in the flange grooves, such as weld slag and rust, was not removed； 2. The thermal tightening does not keep up as the temperature rises.
Is the octagonal pad still leaking? It’s probably a quality issue with the installation; replace the gaskets again, making sure to check the quality of those gaskets. Also, when replacing the gaskets, carefully inspect the sealing surfaces for any impurities such as weld slag
1. Quality issues with the gaskets. 2. Construction quality issues. 3. There is no thermal tightening, and the above problems are difficult to resolve; therefore, we changed all the parts that could be replaced with welded valves to welded ones, thus solving the problem.