“U型”双排排列辐射炉管的工业应用

Industrial application of double row arrangement of U type radiant coil in cracking furnace

为了掌握辐射炉管双排排布对其工艺性能及机械性能的影响,本文采用计算流体动力学方法对采用U型双排排列辐射炉管裂解炉辐射室的燃料燃烧、辐射传热、管内反应等进行了耦合模拟计算,管内采用简化裂解反应模型、管外燃料燃烧采用EDC详细化学反应模型、辐射传热采用Discrete Ordinates模型、计算采用标准κ-ε双方程模型。计算在Fluent 6.3软件中完成,计算得到了"U"型双排排列辐射炉管沿长度方向及周向的热强度分布及温度分布,管壁最高温度出现在距离炉底35%的炉膛高度位置,炉管"迎火面"与"背火面"的最大温度差为30℃左右。收集了采用本方案的工业装置实际运行数据,工业实测数据与数值模拟计算结果吻合较好。工业实际应用表明,"U"型双排排列辐射炉管不但工艺性能优良,同时还具有良好的抗弯曲变形的机械性能。

Three dimensional coupled simulation of flow, combustion, radiation heat transfer and cracking reaction inside tubes of double rows arrangement of U congfiguration radian coil was carried out in Computational Fluid Dynamics（CFD） software Fluent 6.3. The geometrical model was estabished with the ration of 1：1 according to the real furnace.The EDC detailed chemical reaction model was used for combustion. The Discrete Ordinates model was adopted for radiation heat transfer. Simplified cracking reaction model was employed to describe pyrolysis reaction inside radiant tubes. The standard κ-ε dual equations model was used for terative computations. The mesh was generated by software ICEM 11.0. Both longitudinal and circumferential heat flux profile and TMT （Tube Metal Temperature） profile were obtained. Simulation results show that the max TMT occurs at 35% elevation from the hearth of the outlet tubes. The TMT＇s difference between the side exposed to flame and the side between two rows is around 30 degree centigrade. Industrial operating data of the furnace were gathered and fitted well with the CFD simulation results. The industrial practices show the double rows arrangement of U type coil is provided with not only the perfect process performances but also excellent mechanical performance of bowing resistance.