超声强化亚临界CO_2萃取的动力学模型及机理  

Kinetic Model and Mechanism of Ultrasonic-Enhanced Subcritical CO_2 Extraction

作　　者：丘泰球[1] 李超[2] 谭伟[3] 杨日福[1] 黄星歆[1] 范晓丹[1] 

机构地区：[1]华南理工大学轻工与食品学院,广东广州510640 [2]徐州工程学院食品工程学院,江苏徐州221008 [3]广东工业大学轻工化工学院,广东广州510006

出　　处：《华南理工大学学报（自然科学版）》2010年第12期124-128,150,共6页Journal of South China University of Technology(Natural Science Edition)

基　　金：国家"十一五"科技支撑计划重点项目(2006BAD27B03)

摘　　要：为了研究超声强化亚临界CO2萃取的机理,说明超声对亚临界CO2萃取的传质强化效果,借助萃取动力学模型对实验数据进行了拟合,并通过超声空化阈值的理论计算,得到亚临界CO2的空化阈值随温度和压力的变化,同时结合超声空化的验证实验,探讨了超声在亚临界CO2中的空化情况.结果表明:动力学方程能够较好地拟合萃取实验结果,模型方程中有无超声的E∞和k值的差异也证实了超声对亚临界CO2萃取有明显的传质强化效果;相对较高的温度和较低的压力更有利于超声空化效应的产生;亚临界CO2在理论计算不可能出现超声空化的条件下同样存在空化效应,此现象尚无合理的解释;超声强化亚临界CO2萃取的机理包括空化效应和强化传质.In order to reveal the enhancement mechanism of subcritical CO2 extraction by ultrasonic and describe the mass transfer enhanced with ultrasonic,some experiments were carried out and the data were fitted with the help of a kinetic extraction model.Then,the cavitations threshold at variable temperature and pressure were obtained based on theoretical calculation.Moreover,the cativation in the subcritical CO2 extraction enhanced by ultrasonic was investigated according to the results of the experiments.The results show that（1） the established kinetic model fits the extraction data well;（2） the difference in E∞ and k values between the extractions with and without ultrasonic enhancement also confirm the obvious enhancement effect of ultrasonic for the mass transfer in subcritical CO2 extraction;（3） the occurrence of ultrasonic cavitation is rather easy at relatively high temperature and low pressure;（4） the cavitation occurs even under the conditions that cavitation is theoretically unavailable,for which there is no reasonable explanation;and（5） the enhancement is mainly due to the cavitation effect and the enhanced mass transfer.

关 键 词：超声波 亚临界CO2萃取 动力学模型 机理 

分 类 号：TQ645.96[化学工程—精细化工]