乙烯裂解炉辐射段流动与燃烧的三维数值模拟

用计算流体力学软件Fluent6.2对中国石油化工股份有限公司燕山分公司E-BA-107乙烯裂解炉辐射段内的流动和燃烧做了三维数值模拟研究。为保证计算的准确性,使用GAMBIT2.2软件建立了与裂解炉实际尺寸完全一致的几何模型;在计算过程中采用了标准k-ε湍流模型、离散坐标辐射模型和有限速率/涡流耗散燃烧反应模型等计算模型。通过模拟计算得到了裂解炉炉膛内的温度、烟气流速及烟气组成的分布:底部燃烧器和侧壁燃烧器的燃烧使附近的炉墙处于温度分布均匀的高温区,为裂解反应提供了均匀的辐射墙面;炉管底部比其他部位的温度低;底部燃烧器的高速射流产生的旋涡可为炉管提供一定的对流热;出口烟气的平均温度和组成的模拟计算值与设计值接近,表明数值模拟有较高的精度,具有实际意义。

Three Dimensional Numerical Simulation of Flow and Combustion in Firebox of Ethylene Cracking Furnace

Three dimensional flow and combustion in firebox of ethylene cracking furnace were simulated by using computational fluid dynamics software Fluent 6.2.Actual cracking furnace geometric model was established by using software GAMBIT 2.2 to ensure accuracy of the simulation.Standard k-ε turbulence model,discrete coordinate radiation model and finite-rate/eddy-dissipation model were used in the calculation.The distributions of temperature,velocity and composition of flue gas were obtained by the simulation.Flames of bottom burners and side wall burners make nearby furnace walls be in uniform high temperature field,providing well-distributed radiation heat to reactor tubes.Temperature around bottom tubes is lower than that of other parts.Vortices brought about by high gas flows from bottom burners can supply convective heat to reactor tubes.The calculated temperature and composition of the flue gas at the outlet are in good agreement with design data.