抄録
Flow-Accelerated Corrosion (FAC) is a pipe wall thinning phenomenon to be monitored and managed in power plants with high priority. At present, its management has been conducted with conservative evaluation of thinning rate and residual lifetime of the piping based on wall thickness measurements. In heat recovery steam generator (HRSG) of the combined cycle thermal power station, it is possible that FAC can occur due to complicated flow structure in a variety of continuous pipe elements which configures HRSG. However, HRSG is defined as an equipment in Japanese codes of wall thinning management. Thus, HRSG is not an object of wall thickness measurements. If autonomous measurement is conducted at the site, there can be some parts which measurement is difficult to be done because of complicated pipe layout. In this study, numerical analysis for two types of HRSG pipe layout was conducted, and the wall thinning profile by FAC was evaluated. Noticeable wall thinning profiles at the heating pipe were found near the location of the guide pipe regardless of the type of HRSG. And it was confirmed that there is almost linear relationship between max amount of wall thinning and the ratio of the guide pipe’s diameter to the header’s diameter. Therefore, this ratio can be helpful for the prediction of the wall thinning tendency.
