模拟乙烷裂解炉管中流体返混对烧焦过程的影响

针对裂解炉管弯头处流体运动状态变化的特点,采用柱塞流反应器(PFR)与串联全混流反应器(CSTR)组合的反应器模型,耦合计算了炉膛传热和辐射段炉管内的烧焦过程.将烧焦时焦炭表面氧分压、烧焦速率、炉管出口气体温度和碳氧化物含量、焦炭层厚度等影响的模拟结果与无返混的PFR模型的模拟结果进行了比较.结果表明:两种模型模拟的炉管出口气体温度和碳氧化物含量均与生产实际基本相合,但有返混的模型能更准确地描述烧焦结束时残碳在管内的分布特点.

Simulation for Influence of Gaseous Back-Mixing on Decoking Process in a Ethane Pyrolysis Furnace

For the direction changing of gas flow at bend of pyrolysis coil,the combined model of plug flow reactor(PFR)model and continuous stirred tank reactor(CSTR)in series model was used to simulate the decoking process by coupling both heat transfer in firebox and coils.The simulated partial pressure of oxygen on the coke surface,decoking rate,the process gas temperature and mole fraction of carbon oxides at coil outlet.coke layer thickness were contrasted to those calculated by PFR model with no back mixing.The results showed that the process gas temperature and mole fraction of carbon oxides at coil outlet by two models were approximately agree with the actual production,but the back mixing model could be more accurate to describe the residual coke distribution at the end of decoking.