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在已有的关于超临界萃取过程的几个假设基础上,由Navier-Stocks方程求出了溶质颗粒周边的湍流流场,结合Higbie的溶质渗透模型,建立起了流速与传质系数的联系.通过比对超声场作用前后的传质系数,提出了传质系数超声强化因子这一新参数.传质系数强化因子表达式给出了超声波强化超临界二氧化碳萃取过程的数理模型.模型给出了超声波功率、超声波频率及溶质颗粒半径同传质系数强化因子的关系.通过比较超临界二氧化碳萃取及超声强化超临界二氧化碳萃取两种方法在薏苡仁中提取薏苡仁油和薏苡仁脂及在海藻中提取二十碳五烯酸和二十二碳六烯酸的实验结果与本模型的计算结果,验证了所提出的传质系数强化因子这一数理模型的合理性.模型为超声强化超临界萃取技术应用提供了理论指导.
Based on the existing assumptions about the supercritical fluid extraction process, the turbulent flow around the solute particles was calculated by the Navier-Stocks equation, and the relationship between the flow rate and the mass transfer coefficient was established based on the solute permeation model of Higbie. By comparing the mass transfer coefficients before and after the ultrasonic field, a new parameter of mass transfer coefficient is given.The mathematical model of ultrasonic enhanced supercritical carbon dioxide extraction is given.The expression of the mass transfer coefficient enhancement factor is given Ultrasound power, ultrasonic frequency and solute particle radius with the mass transfer coefficient enhancement factor.Compared with supercritical carbon dioxide extraction and ultrasonic enhanced supercritical carbon dioxide extraction of Coix seed oil and Coix seed oil extract and in seaweed The experimental results of extracting eicosapentaenoic acid and docosahexaenoic acid and the calculation results of this model verify the rationality of the proposed mathematical model of mass transfer coefficient enhancement factor.The model is the result of ultrasonic enhanced supercritical fluid extraction Technical application provides theoretical guidance.