基于三维数值模拟的焦炭塔塔体失效研究

A three-dimensional numerical simulation-based study of coke drum failure

建立了结构上完整的焦炭塔三维有限元分析模型,考虑了塔内焦炭对塔体受力的影响以及内压边界随时间变化等因素,对焦炭塔整个工作过程进行瞬态温度-结构耦合分析,模拟应力、应变场,并与塔体失效的实际检测结果进行对比分析。采用间接耦合方法进行焦炭塔结构分析,选用Solid 45单元。分析结果表明,周期变化的温差应力是焦炭塔产生高应力的根本原因,尤其是水冷阶段焦炭塔温度迅速降低,产生了较高的热应力;焦炭塔1个工作周期内,下部筒体环焊缝和裙座搭接焊缝等开裂部位承受着大幅值的循环热应力作用。

The three-dimensional finite element analysis model for coke drum was established in terms of structural completeness.The effect of coke within the drum on the drum body and thechange of internal pressure boundary with time wereconsidered. An instantaneous temperature-structure couplinganalysis of the entire operating process of coke drum wasconducted. The stress and strain fields were simulated. Thefindings were analyzed through a comparison with the actuallydetected result of the drum failure. The indirect couplingmethod was adopted to carry out a structural analysis of cokedrum and the Solid 45 element was selected. The analysisshows that the temperature difference stress with cyclic changeis the fundamental reason for production of high stress in cokedrum. Particularly in the water cooling period the temperatureof coke drum drops quickly, producing relatively high thermalstress. In one operating cycle of coke drum there is alarge-amplitude cyclic thermal stress effect on the crackingpositions, such as the weld of lower cylinder ring and the skirtlap weld.