利用详细燃烧模型对裂解炉二维模型富氧燃烧过程进行数值模拟

2D numerical simulation of oxygen-enriched combustion process in cracking furnace using detailed combustion model

利用计算流体力学软件Fluent对裂解炉燃烧器二维模型富氧燃烧过程进行数值模拟,研究了富氧燃烧技术对裂解炉炉膛内燃烧过程的影响。采用详细燃烧模型,即41步甲烷燃烧骨干机理和涡耗散概念模型进行耦合计算,详细准确描述了富氧燃烧过程。湍流模型采用标准k-湍流模型,辐射模型采用P-1模型。模拟计算结果表明,随助燃空气中氧气含量的增大,燃料燃烧更加完全,燃烧反应放热量增大。当氧气含量(w)从23.5%增至36.5%时,炉膛内平均温度升高了7.93%、峰值温度升高了4.33%、烟气出口处温度升高了3.56%、烟气出口处CO含量降低了54.5%、烟气出口处CO_2含量升高了9.23%、烟气出口处NO_x含量增幅较大(达到了0.350 5%)。

The influences of the oxygen-enriched combustion technology on temperature field, velocity field, reactant concentration and fuel consumption in cracking furnace were investigated through a 2D simulation to predict the oxygen-enriched combustion process using the commercial software Fluent. To describe the combustion process accurately, a CHEMKIN file including 16 species and 41 reactions was introduced into the Fluent software. The simulation also took into account the standard k-e turbulence model, P-1 radiation model and turbulence-chemistry interaction. The results showed that, with increasing the oxygen concentration, the fuel burned more completely and the reaction heat increased. When the oxygen concentration（w） increased from 23.5% to 36.5%, in the furnace, the average temperature increased by 7.93% and the peak temperature increased by 4.33%; and at the effluent gas outlet of the furnace, the temperature increased by 3.56%, the CO concentration reduced by 54.5%, the CO2 concentration increased by 9.23% and the NOx concentration increased to 0.350 5%.