水添分解圧力容器用高強度Cr-Mo鋼の現状

抄録

Recently larger and thicker pressure vessels have been required in hydro-treating processes of oil upgrading and synthetic fuel production. In order to meet such tendency, conventional Cr-Mo pressure vessel steels have to be improved in hardenability, design stress intensity and resistance to severe internal environments.
Several enhanced Cr-Mo steels such as 3Cr-1Mo-1/4 V-Ti-B steel and21/4 Cr-1Mo-1/4 V steel have been developed and put into ASTM and ASME Code. The newly developed enhanced Cr-Mo steels have excellent high temperature creep rupture properties, low enough susceptibility to long term degradation at elevated temperature and also sufficient resistance to hydrogen attack and hydrogen embrittlement.
Construction of hydrotreating pressure vessels is properly selected considering vessel integrity, maintainability and manufacturing convenience of large size and heavy wall pressure vessels. The forged ring welded construction may be the most preferable design which meets above requirements. Manufacuring of heavy wall pressure vessels made from enhanced Cr-Mo steels requires stringent heat treatment control and suitable welding materials. Application of enhanced Cr-Mo steels also makes echonomical advantages due to reduction of wall wall thickness and total vessel weights.
Large size hydrotreating reactors made from 3Cr-1Mo-1/4 V-Ti-B steel are now manufacturing in shop under the requirement of ASME Code Section VIII Division 2.