SL-Ⅱ型乙烯裂解炉炉内流动特性的研究

Research on flow patterns of SL-Ⅱ ethylene cracking furnace

乙烯裂解炉底部燃烧器的燃气射流,使炉内烟气流动复杂,烟气温度分布的均匀性较差。为了解实际裂解炉膛内较难观察到的气体流动状态并为裂解炉膛内合理的流动组织提供调整依据,以优化炉内燃烧,通过冷态模型研究了裂解炉炉膛内气流速度场。利用PIV技术测量炉内流场速度,得到了不同工况下的流场图和炉内气速分布规律。结果表明炉内流场主要受底部燃烧器的影响,而侧壁燃烧器由于负荷相对较小,对炉内流场影响较小;底部燃烧器的气体射流在炉膛下部管排两侧各形成一个回流区,由于炉膛结构的影响导致了炉膛上部管排两侧的非对称速度分布。

Complex pattems of flue gas and non-uniform temperature distribution along fumace height were taken place due to high jet velocity of bottom bumers in the ethylene cracking fumace. The gas flow field was studied based on cold model in order to reveal gas flow pattems which can be as references to regulate reasonable flow patterns in the cracking fumace. The gas flow velocity was measured by PIV. Gas flow graphs and gas velocity distribution characteristics at different conditions were obtained. Experimental results showed gas flow pattems in the fumace were affected mainly by bottom bumers and effects of side bumers can be neglected due to lesser load of side bumers. The cireumfluence zone was found at the each side of tubes due to high jet velocity from bottom bumers. There was unsymmetrical velocity distribution in the top of the fumace because of furnace structure .