The Control of Two-Phase Flow-Accelerated Corrosion
Flow-accelerated or flow-assisted corrosion (FAC) is the uncontrolled dissolution and transportation of iron oxides in a steam-water cycle system that occurs in both single-phase locations (water) and two-phase locations (water and steam). Single-phase FAC can be mitigated by chemical controls, but two-phase FAC remains largely unaddressed by industry’s available product options due to the challenging nature of both water and steam presence in the same location. This hazardous corrosion mechanism poses a serious threat to the safety and reliability of a system, as it can cause several undesirable maintenance/operational conditions and, if left unchecked, can result in dangerous and costly failures.
This paper focuses on a 870 MW CCGT plant located in Europe and their pursuit towards plant optimization, which led to the eventual introduction of the Anodamine HPFG product into their system. After the application of Anodamine HPFG, the plant’s two-phase FAC was drastically mitigated, along with reduced maintenance costs, shorter start-ups, and the removal of costly shutdown methods of nitrogen blanketing and dehumidified air. Results were validated using industry-recognized total iron digestion analysis, millipore filter tests, online laser nephelometer readings, and physical equipment inspections.