Materials and structures of coke drum

The mechanisms and particularities of the high-temperature sulfur corrosion of the coke drum are reviewed,and the relative merits of using different materials are analyzed.Based upon the status-quo of coke drums both in China and abroad,the recommendations for material selections for the shell,cladding and weld used to join cladding of the coke drum are given.Two phenomenons of low-frequency fatigue failure,shell bulging and fatigue crack are highlighted.The impact of the top structures of the skirt on the low-frequency fatigue failure of the coke drum is described.The characteristics of the arc transition joint types on the top of the skirt and the integral forge-welding structure as well as structure design precautions are analyzed.Improvement measures for the top of skirt,cylindrical shell,nozzle and insulation are proposed.