摘要
目的优化胡萝卜的热泵干燥工艺,并提升胡萝卜干燥后的品质。方法研究干燥初始温度、干燥温升值和切片厚度对胡萝卜热泵干燥特性的影响,并探讨上述条件与有效水分扩散系数和干燥活化能的关系。确定可以精确预测胡萝卜热泵干燥时含水率变化的干燥动力学模型,进而预测胡萝卜在不同热泵干燥条件下的体积变化规律。结果干燥速率的变化与初始干燥温度、温升值的变化呈正相关,与切片厚度呈负相关;胡萝卜在热泵干燥过程中表现为降速过程,其中,切片厚度对干燥速率的影响最大,温升值对干燥速率的影响最小;对比分析了4种薄层干燥模型,Page模型能更好地描述胡萝卜的热泵干燥过程和水分迁移规律,模型所得拟合值相对于试验值的平均误差为5.76%;在此次试验范围内,胡萝卜的有效水分扩散系数介于3.0401×10^(−10)~7.1555×10^(−10) m^(2)/s之间。该系数随着干燥温度的提高、温升值的增大及切片厚度的减小而呈增加的趋势。通过Arrhenius方程计算得到该试验条件下胡萝卜的干燥活化能为13.374 kJ/mol。结论Page模型能够更好地预测胡萝卜在热泵干燥过程中水分的迁移规律,从而优化热泵干燥工艺参数,为胡萝卜热泵干燥的工业化运用提供理论基础。
The work aims to optimize the heat pump drying process and improve the quality of dried carrots.The effects of the initial drying temperature,drying temperature rise value and slice thickness on the heat pump drying characteristics of carrots were investigated,and the relations of these conditions on the effective moisture diffusion coefficient and drying activation energy were explored.A drying kinetic model that could accurately predict the changes in moisture content of carrots during heat pump drying was identified,thus the moisture migration pattern of carrots under different heat pump drying conditions could be predicted.The variation of drying rate was positively correlated with the variation of initial drying temperature and temperature rise value,and negatively correlated with slice thickness.The carrot heat pump drying process showed a decreasing rate,where the slice thickness had the greatest influence on the drying rate and the temperature rise valueΔθhad the least influence.Comparing analysis of four thin-layer drying models showed that the Page model could better describe the drying process and moisture migration of carrot heat pump,with an average error of 5.76%in the fitted values relative to the test values.Within the scope of this test,the effective water diffusion coefficient of carrots ranged from 3.0401×10^(−10)~7.1555×10^(−10) m^(2)/s.This coefficient showed an increasing trend as the drying temperature,the temperature rise value increased,and the slice thickness decreased.The Arrhenius equation showed that the activation energy of carrot drying under this test condition was 13.374 kJ/mol.In conclusion,the Page model can better predict the moisture migration pattern during carrot heat pump drying and thus optimize the heat pump drying process parameters.The research conducted in this paper provides a theoretical basis for the industrial production of carrot heat pump drying.
作者
李改莲
韩琭丛
王广红
彭钰航
金听祥
LI Gailian;HAN Lucong;WANG Guanghong;PENG Yuhang;JIN Tingxiang(School of Energy and Power Engineering,Zhengzhou University of Light Industry,Zhengzhou 450002,China)
出处
《包装工程》
CAS
北大核心
2024年第1期10-18,共9页
Packaging Engineering
基金
河南省科技攻关项目(222102320075)
河南省研究生教育创新培养基地项目(YJS2021JD05)。
关键词
干燥特性
干燥动力学
热泵干燥
干燥活化能
有效水分扩散系数
drying characteristics
drying kinetics
heat pump drying
activation energy
effective moisture diffusion coefficient