ENSURING FIRE SAFETY OF PIPELINE SECTIONS WITH CORROSION OF MAIN OIL AND GAS PIPELINES

Currently, corrosion of the pipeline wall of main oil and gas pipelines is one of the main reasons for their failures and accidents. A decrease in the pipeline wall thickness due to corrosion leads to a significant decrease in the load-bearing capacity (strength) of the pipes and an increase of mechanical stress in their wall. As a result, the probability of a pipe wall rupture increases. In some cases, a pipe wall rupture leads to ignition of the pumped product. This is especially typical for gas pipeline damage. In order to eliminate the possibility of a fire, it is necessary to promptly detect sections of the pipeline with corrosion and carry out repair work. Repair work is aimed at increasing the load-bearing capacity (strength) of the corroded section and reducing of mechanical stress in the pipeline wall in the damaged section. Various types of repair structures are used to repair a corroded pipeline wall. Repair couplings are quite widely used. The coupling takes up part of the load from the action of the operating pressure and reduces the level of mechanical stress in the pipe wall in the section of the pipeline with corrosion to an acceptable level. The rupture of the corroded section and the occurrence of a fire are excluded. At the same time, reducing the level of mechanical stresses in the defective section, the installation of the coupling on the pipeline leads to an increase in the level of stresses and the occurrence of the probability of a pipe rupture in the sections immediately adjacent to the coupling. In this regard, when solving the problem of ensuring fire safety of a section of a pipeline with corrosion using a repair coupling, it is necessary to analyze the strength and safety of the sections of the pipeline adjacent to the coupling.The purpose of the work is to ensure fire safety of a corroded section of a pipeline based on decrease of mechanical stress and increase of pipe safety against failure to an acceptable level.Research methods – a theoretical study of the stress-strain state under the action of the working pressure of a pipeline section with corrosion repaired by installing a coupling.Results – analytical dependences of the strength of the operated pipeline on the amount of corrosion of the pipe wall, geometric characteristics of the coupling and the pipeline are obtained. Recommendations for ensuring fire safety of a section of a pipeline with corrosion when using a repair steel coupling are formulated.