焦炭塔的套合效应研究

Nested-Effect Research of Coke Drum

借助于有限元方法对一焦炭塔进行了瞬态热传导模拟,并将温度场顺次耦合于应力场,计算出了塔壁、焦床在降温完成后的应力场分布。将节点1800在无焦床作用时的各向应力与有焦床时的进行了对比分析,结果表明,降温阶段焦床与塔壁发生套合,使得塔壁内的周向、轴向应力大幅提高。为验证有限元计算的有效性,对套合效应进行了理论计算,得出了焦床对塔壁的周向套合应力值,结果同样表明,焦炭的套合作用显著,并且理论值与有限元值基本吻合。从而确定,焦炭塔的套合效应是继热机载荷之后,又一个对筒体鼓凸变形、焊缝开裂起决定性影响的因素。

A numerical simulation of transient temperature has been done by FEA in this paper. By a method of progressive coupling temperature filed on stress field, steady stress of shell and coke bed was calculated. After that,the component stress of Node-1800 without consideration of Nested-Effect was compared to that with consideration of Nested-effect. The comparative result shows that, during the temperature-fall period, Nested-effect greatly raises the circumferencial and axial stress of shell. At last, in order to eomfirm the result given by FEA, a theoretical calculation was carried on. It can mainly match with the FEA. Obviously,in addition to thermal and mechanical stress, Nested-Effect can also be one of the most important factors leading to shell bulging and weld cracks.