Distribution of dynamic stress on the supercritical CO₂ pipeline in the process of its pressure relief

The intensity and distribution of stress on the supercritical CO₂ pipeline in the process of its pressure relief are less studied and the initial conditions of its pressure relief are not defined clearly in the relevant specifictions and standards. In this paper, the distribution of stress and temperature on the supercritical CO₂ pipeline in the process of its pressure relief and their influential factors were studied, and the stress response in the process of pipeline pressure relief under different initial temperatures and pressures was simulated by means of the finite element method. It is indicated that the temperature difference between the inner and outer walls during the pressure relief of supercritical CO₂ pipeline is very small, so the thermal stress generated by temperature difference can be neglected. Besides, the temperature, equivalent stress and radial stress after the pipeline pressure relief change linearly approximately along the wall thickness from the inner wall to the outer wall. The greater the initial pipeline pressure is, the higher the equivalent stress and the radial stress on the wall after the pressure relief are, but the pipeline temperature drop amplitude is smaller. And the lower the initial temperature inside the pipeline is, the higher the equivalent stress and radial stress on the wall are and the longer it takes to vent the pipeline. The research results provide some basis for the preparation of supercritical CO₂ pipeline venting scheme and the formulation of related specifictions and standards. (4 Figures, 20 References)