Abstract:

The burner used in cracking furnace is the key equipment of ethylene plant. It must meet the specific technological requirements and the increasingly strict environmental requirements while keeping the combustion stable. In recent years, the rise of porous medium combustion technology has brought new changes to the burner of ethylene cracking furnace. A new porous medium burner for ethylene cracking furnace was designed and developed by CFD technology and hot experimental method. The combustion state in the double-layer porous media structure was studied by numerical analysis. The upstream of the porous media region was 30 PPI Al₂O₃ foam ceramics, and the downstream was 10 PPI SiC foam ceramics. It was found that the combustion atmosphere in the cracking furnace was more consistent with the equivalent ratio of φ=0.8 and the inlet flow rate u₀=0.8m/s. The joint simulation of the traditional bottom burner and the porous medium side-wall burner in the cracking furnace was carried out. The simulation results showed that the temperature distribution in the furnace was uniform and met the requirements of process and environmental protection. Two porous media burners were prepared and combined with bottom burners for test firing in hot state test furnace. The flame stability was mainly observed. The experimental results showed that the combustion state was good and the NO _x emission was lower.

Key words: burner for cracking furnace, porous media, combustion, pollution, numerical analysis, hot state test

摘要：

裂解炉用燃烧器是乙烯装置的关键装备，在稳定燃烧的同时又要满足特定的工艺要求和日益严苛的环保要求。近年来多孔介质燃烧技术的兴起，为乙烯裂解炉燃烧器带来了新的变革。本文利用CFD技术和热态试验方法设计开发出一种新型乙烯裂解炉用多孔介质燃烧器。通过数值分析研究双层多孔介质结构内的燃烧状态，其多孔介质区域上游为30PPI的Al₂O₃泡沫陶瓷，下游为10PPI的SiC泡沫陶瓷，研究发现在当量比φ=0.8、入口流速 u₀=0.8m/s时更符合裂解炉内燃烧氛围。对裂解炉内传统底部燃烧器+多孔介质侧壁燃烧器进行联合仿真，仿真结果表明，炉膛内温度分布均匀且满足工艺要求和环保要求。制备2台多孔介质燃烧器联合底部燃烧器在热态试验炉上试烧，主要观察其火焰稳定性，实验结果表明，燃烧状态良好且NO _x 排放更低。

关键词: 裂解炉用燃烧器, 多孔介质, 燃烧, 污染, 数值分析, 热态试验