Blowdown of LPG Pipelines

In order to be able properly to assess the hazards associated with the rapid depressurization or blowdown of an oil, gas or condensate pipeline, there is a need to be able to predict fluid pressure, fluid and wall temperatures and effux rate, composition and phase. Several computer programs have been developed to do this, including our program BLOWDOWN. A comparison is made here of BLOWDOWN predictions with the measurements made during eight of the tests using LPG carried out by Shell and BP on the Isle of Grain in 1985. Four of the tests were for full-bore depressurizations and four for depressurizations with orifices at the open ends of the lines. The BLOWDOWN predictions are shown to be in at least adequate, and often good, agreement with the Isle of Grain measurements.