环己酮肟Beckmann重排反应微观混合的数值模拟

Numerical simulation of micromixing in Beckmann rearrangement of cyclohexanone oxime

采用涡流卷吸-变形-扩散模型,结合反应动力学,对环己酮肟Beckmann重排反应微观混合进行了数值模拟,讨论了工业重排过程中关键工艺参数对反应和传质的影响。结果表明,重排反应过程受微观混合控制,从理论上解释了环己酮肟Beckmann重排最小理论酸量与实际生产值的差异。温度的上升有利于分子扩散的进行,但宏观上造成产品质量下降;反应混合器喷嘴直径适当的减小可提高微观混合的效果,有利于改善传质效果和保证成品质量。

Numerical simulation of micromixing in Beckmann rearrangement of cyclohexanone oxime was carried out with engulfment-deformation-diffusion model by taking into account the reaction kinetics.The effects of key industrial parameters on the reaction and mass transfer were investigated.The results showed that Beckmann rearrangement was micromixing controlled and the local molar ratio of acid to oxime was lower than the value in macro-scale process,which deviated from the normal reaction condition and explained the difference between the theoretical minimum acid amount and industrial value.Higher temperature leaded to poor quality of product though it was in favor of molecular diffusion.Decrease in the diameter of mixer resulted in better micromixing to some extent,which may improve mass transfer and the quality of caprolactam.