Comparison of displacement mitigation solutions of pig launcher in gas gathering station

The pig receiver/launcher inside the gas gathering station is connected to the buried pipeline outside the station by a transition section. When the operating temperature is higher than the installation temperature, the buried pipeline will suffer thermal expansion, which makes the ground pipeline push equipment or valves and thereby cause them damaged or excessively deformed. In this paper, the stress analysis software CAESAR Ⅱ is used to analyze the impacts of the secondary stress of buried pipelines on the anchor pier of pig launcher in a gas gathering station. The renovation of pig launcher and pipelines in a gas gathering station shows that, the displacement of pig launcher is mitigated effectively by setting a 45° π-shaped compensation structure and using sliding support instead of ground support, so that the pigging is conducted smoothly and the pig launcher runs normally. The practices prove the feasibility of such renovation scheme.