Modeling of moisture diffusivity, activation energy and energy consumption in fluidized bed drying of rough rice

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• 作者：Majid Khanali ; Alireza Banisharif ; Shahin Rafiee
• 刊名：Heat and Mass Transfer
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：52
• 期：11
• 页码：2541-2549
• 全文大小：734 KB
• 刊物类别：Engineering
• 刊物主题：Engineering Thermodynamics and Transport Phenomena
  Industrial Chemistry and Chemical Engineering
  Thermodynamics
  Physics and Applied Physics in Engineering
  Theoretical and Applied Mechanics
  Engineering Fluid Dynamics
  
• 出版者：Springer Berlin / Heidelberg
• ISSN：1432-1181
• 卷排序：52

文摘

The present work was an attempt to assess the effective moisture diffusivity, activation energy, and energy consumption of rough rice in a batch fluidized bed dryer. Drying experiments were conducted at drying air temperatures of 50, 60, and 70 °C, superficial fluidization velocities of 2.3, 2.5, and 2.8 m/s, and solids holdup of 1.32 kg. Drying kinetics showed that the whole fluidized bed drying of rough rice occurred in the falling rate period. The effective moisture diffusivity was described by an Arrhenius equation. The evaluated effective moisture diffusivity increased with drying air temperature and superficial fluidization velocity and was found to vary from 4.78 × 10−11 to 1.364 × 10−10 m2/s with R2 higher than 0.9643. The activation energy and the pre-exponential factor of Arrhenius equation were found to be in the range of 36.59–44.31 kJ/mol and 4.71 × 10−5–7.15 × 10−4 m2/s, respectively. Both maximum values of the specific energy consumption of 74.73 MJ/kg and the total energy need of 12.43 MJ were obtained at 60 °C drying air temperature and 2.8 m/s superficial fluidization velocity. Both minimum values of the specific energy consumption of 29.98 MJ/kg and the total energy need of 4.85 MJ were obtained under drying air temperature of 70 °C and superficial fluidization velocity of 2.3 m/s.