Corrosion in Pulp Mills : Material Selection for an Evaporation Plant

Sammanfattning: Corrosion is a global problem which leads to both economicalct on the environment as well as other negative social and ethical aspects. Sodra Cell Monsteras, one of the largest producer of pulp in the world, suffers from corrosion problems in their evaporation plant. Problems with corrosion can be handled with an effective material selection process, where suitable materials for specific conditions is discovered. The purpose with this report is to investigate the evaporation plant at Sodra Cell and its specific conditions, including environment and temperature. Also to investigate different types of corrosions common in pulp mills and how these can be prevented, as well as how materials behave under corrosive circumstances. The information is later to be used in a detailed material selection process, which is handled in this report but also should work as a foundation for Sodra Cell Monsteras for future material selections. The material selection process in this report is performed according to Ashby's method, with CES Edupack as a supporting tool. The duplex steels, especially EN 1.4485 and EN 1.4362, showed to be the best suitable materials. However, to do a fair judgment and to choose one material, one should do a complete cost efficiency analysis, as well as decide a specific required pitting resistance equivalent number (PREN).