In-line Inspection Corrosion Direct Assessment of Shutdown Dry Natural Gas Pipeline
According to the requirements of integrity evaluation,the integrity evaluation of the newly built pipeline will be completed within 3 years after it is put into operation.If the pipeline does not have the conditions for internal inspection,the method of direct evaluation of internal corrosion can be used to evaluate the pipe section.A natural gas pipeline in Jiangxi province does not meet the requirements of internal inspection,and this pipeline is in shutdown state sometime.In order to evaluate the internal corrosion risk of the pipeline section,the internal corrosion is evaluated directly,including pre-evaluation,indirect evaluation,direct evaluation and post-evaluation.The sensitive and high risk points of internal corrosion are given,the excavation points are selected for detailed inspection,and the causes of internal corrosion are analyzed according to the production conditions.The results show that the maximum wall thickness loss of a natural gas pipeline in Jiangxi is 0.20mm,the maximum wall thickness reduction rate is 2.3%,and the degree of corrosion is slight.CO2 corrosion is the main corrosion risk in production stage and shutdown stage.
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