操作参数对Cr-Mo钢焦炭塔瞬态温度场及热应力影响数值模拟研究

Numerical Simulation of Effect of Operational Parameters on Transient Temperature Field and Thermal Stress of Coke Drum Made by Cr-Mo Steel

针对Cr-Mo钢焦炭塔,利用有限元数值模拟方法中的动态热边界条件,模拟了恒速上升的液体介质沿塔内壁爬升过程,开展了Cr-Mo钢焦炭塔瞬态温度场和热应力数值模拟研究,定量分析了进油速度、进水速度以及冷却水温等操作参数对塔壁瞬态温度场和热应力场的影响规律。研究结果表明,进油和进水阶段,随着介质界面的恒速上升,内壁处产生了较大的轴向温度梯度,塔壁上形成了较高的径向温差。液面升速越快,由温度波动产生的热应力越大。相同冷水升速条件下,水温越低,同一轴向高度的径向温差以及内壁处的轴向温度梯度越大,产生的热应力也越大;相同液面升速下,进水阶段的热应力要高于进油阶段的热应力。研究结果可为定量分析Cr-Mo钢焦炭塔安全状况和剩余寿命提供技术支持。

Aimed at coke drum made by Cr-Mo steel,with the dynamic thermal boundary conditions used in the finite element method,the procedure of the liquid medium climbing inner wall in coke drum with constant speeds were simulated,and the numerical simulation of temperature field and thermal stress of coke drum was conducted. Variation laws of the effect of operational parameters such as the velocity of oil and water,cooling water temperature on the transient temperature field and thermal stress field of coke drum were investigated. Numerical results show that with the rise of media interface during filling oil and water phases,greater axial temperature gradient on inner wall is produced and higher radial temperature difference along drum wall is formed. The faster the surface rising speed is,the larger thermal stress which is generated by the temperature fluctuations is. Under the condition of the same cold water rising speed,the lower the water temperature is,the larger the axial temperature gradient on the inner wall and the radial temperature difference at the same axial height are,and the larger the thermal stress is. At the same liquid level speed,the thermal stress during filling water phase is higher than that during filling oil phase.The results can produce technical supports for the quantitative assessment of the safety and remaining life of coke drum made by Cr-Mo steel.