Under-scale corrosion occurs on the outer wall of the heat exchanger tube bundle of the oil refining atmospheric and vacuum distillation unit’s fourth line oil washing steam generator
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The following images show the heat exchanger tube bundle of the steam generator for the fourth-line wash oil in petrochemical atmospheric and vacuum distillation. The model is FA1200-85-25-8, and the tube bundle material is 10# steel. The operating conditions are: four-line oil washing on the tube side, and desalinated water on the shell side ； The operating temperature is 293 degrees in the tube side and 108 degrees in the shell side ； The pressure in the tube side is 0.817 MPa, and that in the shell side is 0.902 MPa. This tube bundle has been in use for over a year; due to the corrosion caused by desalinated water on the shell side, corrosion started on the outer wall of the tube bundle, with a layer of rust forming on the metal surface. This makes under-scale corrosion more likely to occur.
Due to the use of deionized water in the shell side, corrosion first occurred on the outer surface of the 10# steel tube bundle, thereby forming a layer of rust. This layer of rust can absorb moisture and corrosive agents, accelerating the corrosion process beneath the metal and thus leading to underscale corrosion. To solve this problem, consider improving the water treatment process to reduce the presence of corrosive substances, or choose more corrosion-resistant materials for manufacturing the heat exchanger tubes. .