In petrochemical units, reduced pressure and atmospheric pressure distillation units suffer from both stress corrosion cracking on the outer wall of the steam generator tube bundles and surface corrosion
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The image below shows the tube bundle of the water-cooled cooler on the fifth stage of the atmospheric and vacuum distillation tower in petrochemical industries. The model is YB1000-290-25/25-4, with the tube bundle made of 10# steel. The operating condition is that the tube side operates at reduced pressure and intermediate temperature, while the shell side operates under reduced pressure with steam ； Operating temperature: 214 degrees for the tube side and 104 degrees for the shell side ； The pressure in the tube side is 0.57 MPa, and that in the shell side is 1 MPa. This tube bundle has been in use for over a year, and multiple stress corrosion cracks have appeared on the outer wall of the shell-side tube bundle; at the same time, there are numerous ulcerative corrosion areas as well as large-scale corrosion pits on the surface of the tube bundle. The main reasons are high tube side temperature, unstable operation, and pressure fluctuations. This will cause instability in the steam pressure on the outer wall of the tube bundle, leading to fluctuations. Areas affected by stress concentration in the tubes, such as weak points like welds. Such corrosion phenomena occur as a result of comprehensive effects such as the corrosion of the medium.
In the water coolers of vacuum towers in the petrochemical industry, tube bundles of model YB1000-290-25/25-4 made of 10# steel are used. After operating for nearly a year, the equipment developed multiple stress corrosion cracks and surface corrosion on the outer wall of the shell-side tube bundle. The main reasons are high temperature in the tube side, unstable operation, and pressure fluctuations. High temperatures and unstable operating conditions lead to fluctuations in steam pressure, causing stress concentration in the tube bundles, especially in weak areas such as welds, which in turn triggers problems of stress corrosion cracking and surface corrosion. .