Estimation of the residual resource of vertical cylindrical steel tanks for oil and oil products.

Abstract

The article considers the solution to a number of problems related to the determination of the residual life of steel cylindrical tanks. In the study of negative factors, the main attention is paid to the consideration of corrosion damage that occurs during operation. As a determining parameter of corrosion wear, it is proposed to use the residual thickness of the wall, bottom and roof of structures. The article assumes that forecasting the residual resource includes determining its minimum estimate through calculations. Also, the admissible degree of demolition of investigated designs is established in the work. To do this, a concept of the limit state is established, which is based on the critical reduction of the thickness of the structural elements on a given part of the surface area to the limit value, below which the required margin of the bearing setpoint is not provided. On the basis of the experimental data in the given example the residual and total service life of steel cylindrical tanks is established. The obtained results are commensurate with the allowable standards and service life specified in the regulations. The article establishes the criteria for estimating the residual life of steel cylindrical tanks due to the use of which it is possible to reduce operating costs by increasing the repair intervals. This effect is achieved through the use of the probabilistic-physical approach to assess the objective technical condition and predict the residual life of these structures in the absence of significant failure statistics. Within the framework of the proposed probabilistic-physical approach to estimating durability, a probabilistic model based on the DM-distribution of failures is proposed. The parameters of such a model are based on physical interpretation, and the main parameters are the average rate of change of the determining parameter and the coefficient of variation of the generalized degradation process.