This paper focuses on the corrosion behaviour of high strength flexible wire material immersed in de-aerated 3.5% NaCl solution under 40bar CO2 partial pressure at different test temperatures: 30°C, 40°C and 60°C; different CO2 fluxflux: 0.1ml/min/cm2 and 0.0008ml/min/cm2; different volume of solution to surface area of sample (V/S) ratios: 1ml/cm2 and 0.3ml/cm2 and test durations: 2 and 4 months. The tests were carried out in a lab-scale test system designed and built at TWI Ltd for the simulation of complex annulus environments. The corrosion rates and the maximum depth of the localized attack for tests at different temperatures were recorded as: 30°C>60°C>40°C. This is linked with the stability, structure and thickness of the precipitated iron carbonate scaling. The lowest corrosion rate was recorded for the test with the lowest V/S and slowest CO2 flux, linked with a thin and compact iron carbonate layer. The effect of the flow and degree of confinement are significant at high CO2 partial pressures.
Corrosion Under Insulation (CUI) in pipingc systems consumes a significant percent of the maintenance budget in the petrochemical industry. Prevention of CUI by the use of (1) thermal spray aluminum, (2) stainless steel pipe, (3) expanded metal cages for personnel protection instead of insulation and (4) aluminum foil wrapping are discussed in terms of long term protection, installed cost and Life cycle cost.