乙烯管式裂解炉的数值模拟

Numerical Simulation on Tube-type Ethylene Pyrolyzer

对USC型乙烯管式裂解炉进行了系统的数值模拟,得到了裂解炉内详细的速度、温度及组份浓度分布情况,揭示了裂解炉内流动、传热、传质和反应等过程的基本特点.裂解炉炉膛和反应管分别进行计算,通过管外壁温度相连接,直至吻合.计算结果表明,炉膛内流动、组份浓度和烟气温度分布是相当不均匀的,使反应管管壁温度和热通量分布不均匀;模拟计算还得到了反应管长度方向上的温度、速度、压力和组份浓度的变化规律;在反应管径向上存在着明显的速度和温度分布,而组份浓度变化程度不如速度和温度明显.

Numerical simulation on the USC tube-type ethylene pyrolyzer was carried out. Some detailed information about flow field, temperature field and concentration distribution was obtained, which revealed the basic characteristics of flow, heat transfer, mass transfer and reaction processes in the pyrolyzer. The results indicated that there were highly non-uniform distributions of flue-gas velocity, concentration and temperature in the furnace, which caused non-uniform distribution of tube skin temperature and heat flux of reactor tubes. On the other hand, the profiles of oil-gas velocity, pressure, temperature and components concentration along the vertical direction of reactor tubes were obtained. The steep velocity and temperature gradients along the radial position, and less obvious radial profiles of components concentration were also found.