Risk Based on On-Line Inspection Method for Special Pressure Equipment in LNG Terminal

In order to solve the problem that special pressure equipment in liquefied natural gas (LNG) terminals cannot be stopped for inspection, a new on-line inspection method for special pressure equipment in LNG terminals without shutdown, removal of thermal insulation layer and removal of medium was proposed based on risk based inspection (RBI) concept and the principle of improving scientificity and operability. The method was based on the analysis of the main process flow of LNG terminals and damage modes of special pressure equipment in terminals, in combination with the reliability analysis of transient electromagnetic method (TEM), pulsed eddy current testing, digital radiography and other on-line inspection technology in cryogenic temperature environment. The method covered macroscopic inspection, wall thickness measurement and non-destructive testing and other inspection items, which can effectively discover the potential safety hazards of special pressure equipment in terminals. The division of the corrosion circuit can effectively reduce the sampling proportion of pressure pipelines in terminals and save the inspection time and cost. At the same time as scientific, reasonable and effective inspection, this method can make the special pressure equipment in terminals operate legally and in compliance, which not only can control the operation risk of equipment better, but also can produce huge social and economic benefits.