Study on Compensation of Bent Pipes in Subsea LNG Cryogenic Pipeline
摘要
Because of the factor of environment and safety, the marine LNG loading platform which located away from the coast is the trend of the next generation of LNG loading system. And the subsea LNG cryogenic pipelines are used to connect the marine loading platform and the onshore plant. The contraction of LNG pipeline,which caused by low temperature during operation, mayimpact the structure of pipeline, It is necessary to use compensation structure in the LNG pipeline to deal with the contraction of pipeline.. This paper use bent pipe to compensate the amount of contraction of subsea LNG cryogenic pipeline. The bent pipe will be installed in the land part of LNG pipeline in order to facilitate maintenance.To reduce the cost and prevent the non-uniform change of shape of pipeline, the bent pipe will adopt the structure of single wall line, with insulation on the outer surface of the pipeline. The stress of pipeline, especially at the ends and elbow of pipeline, will be analyzed by finite element model to ensure the stress during the lateral and longitudinal displacement of pipeline is not exceed the yield stress of pipeline. Furthermore, the shape of insulation will change with the pipeline, so it is necessary to study the paving pattern of insulation to ensure the enough insulating property during the changing of the shape of pipeline.