Perpustakaan Digital ITB

Carbon dioxide (CO?) corrosion remains a major threat to the integrity of carbon steel pipelines used in carbon capture and storage (CCS), particularly under multiphase flow where hydrodynamic conditions strongly influence corrosion behavior. Although CO? corrosion has been extensively studied, the influence of specific flow regimes on corrosion severity and the reliability of dissolved iron measurements under flowing conditions remain insufficiently understood. This study investigated the effect of representative multiphase flow regimes on the corrosion behavior of API 5L X80 carbon steel and evaluated the applicability of photometric dissolved iron measurements relative to the conventional gravimetric weightloss method. Corrosion experiments were performed in a horizontal laboratory flow loop using a CO?- mimicking acidic carbonate solution under static immersion, stratified wavy flow, and slug flow. Flow regimes were first characterized to establish representative testing conditions, and corrosion was assessed using gravimetric weight-loss and photometric dissolved iron measurements. The experimental system successfully reproduced representative multiphase flow regimes consistent with the qualitative transition sequence of the Mandhane flow map. Dynamic flow increased corrosion rates by more than two orders of magnitude compared with static immersion despite substantially shorter exposure times, with slug flow consistently producing higher corrosion rates than stratified wavy flow. While photometric dissolved iron measurements showed systematic quantitative deviations from gravimetric measurements under static and flowing conditions, both methods consistently identified corrosion severity. These findings demonstrate that flow regime is a dominant factor governing CO? corrosion of API 5L X80 steel and that dissolved iron measurements should be interpreted with consideration of flow-dependent transport processes. The results provide practical guidance for corrosion monitoring and integrity management of CCS transportation pipelines.