Determining the conditions for stability of elevated pipelines on supports while pigging

The aim of the present study is to determine the maximum allowable pig-running speed which guarantees that the design position of above-ground sections of elevated pipelines is maintained during pigging or liquid cleaning. This paper presents the results of 3D computer modelling, showing the strain in an elevated expansion loop of a pipeline due to the impact of the inertia load during pigging or liquid slug running. The strain in the elevated expansion loop sections of the pipeline was modelled using the finite-element method in the LS-DYNA and ANSYS software packages. Calculations were made for four standard sections of pipeline with expansion loops. As a result, the extent of displacements could be determined for elevated pipelines. The modelling results were used to calculate the maximum pig-running speed at which the design position of the elevated pipeline is maintained. This article compares the results of calculations made using engineering techniques with those made using computer 3D modelling methods. It also presents a comparison of computer modelling performed using the ANSYS and LS-DYNA software packages.