Applying NACE Standard SP0110-2010 Wet Gas Internal Corrosion Direct Assessment Methodology for Shunan Gas Mine Pipeline in Sichuan, China to Assess Internal Corrosion

摘要

This work applied the Wet Gas-Internal Corrosion Direct Assessment (WG-ICDA) standard to assess the severity of internal corrosion of 2 segments along a pipeline used to transport wet gas from a gas mine in Sichuan Province, China. The four sequential steps including (1) pre-assessment, (2) indirect inspection, (3) detailed examination, and (4) post-assessment were followed. A combination of historical data gathering, flow models, and corrosion rate models was used to identify the most probable locations along a flow region for direct assessment. The work was carried out in four steps corresponding to the four steps in the standard. Based on the collected data, applying WG-ICDA standard to this pipeline was determined to be feasible. According to the flow pattern map, the flow was determined to be annular mist flow. The superficial liquid velocity was found to be extremely small. The pressure change along the pipeline was no more than 1%. The liquid holdup was estimated to be very small. A corrosion rate model considering CO_2 partial pressure was used to estimate wall loss. The estimated wall loss from Step 2 fell in the range of measured wall loss after excavation.