ABSTRACT
Metal loss consists of wall thinning, the presence of a corrosive product. The remaining wall thickness of a pipeline must be investigated to determine its safe operating requirements. The remaining life evaluation for corroded pipeline is very important to determine the maintenance time. By the inspection data, the assessment can be implemented through the specified standard and procedure. However, a huge data and evaluated criteria are
1 INTRODUCTION
Pressure vessels and relative equipment of petrochemical plant is the core device of the energy industry. Due to various kind of corrosion, those devices often lead to leaks and induce accidents, such as, the plant casualties, environmental impact, unplanned stop, maintenance costs rising and the deterioration during the operation (Lozev et al., 2005). To ensure the structural safety of petrochemical plant equipment and durability, the government is set for stringent safety regulations and standards, and examined the inspection processes to ensure its safety performance. Reducing maintenance costs, shorten the overhaul schedule, extending the factory operating duration can enhance international competitiveness of the company. How to derive the compromise between the operational safety, profit margin and limited resources is a complicated problem for the company (Ainsworth et al, 2000).
