Phd student, Faculty of Chemical Engineering, Babol Noshirvani University of Technology, Babol, Mazandaran, Iran.
Professor, Faculty of Chemical Engineering, Babol Noshirvani University of Technology, Babol, Mazandaran, Iran.
Food Res Int. 2022 Sep;159:111617. doi: 10.1016/j.foodres.2022.111617. Epub 2022 Jul 5.
This study aimed to investigate how infrared (1000-2000 W) and microwave power (100-900 W), air velocity (1-5 m/s) and temperature (40-80 °C) affected the specific energy consumption, the moisture removal rate, and the product's quality (whiteness index, head rice yield, water uptake ratio, and elongation ratio) in hybrid dryer. Rising temperature, velocity and microwave power and lower temperatures resulted in improving head rice yield of paddy samples. The experiments proved that the new hybrid system significantly increased the moisture removal rate (from 100 to 700%), head rice yield (from 5 to 40 %) and decreased the specific energy consumption (from 10 to 80%) compared to the single fluidized bed dryer. The water uptake ratio and elongation ratio of the dried samples in the hybrid dryer were higher than the single dryer, however their whiteness index was not significantly different. The best drying conditions are associated with the lowest specific energy consumption and the highest moisture removal ratio and rice quality. Experimental data were fitted into empirical drying models to explain moisture ratio variations during drying. Nomhorm and vermas model was found to be the best for moisture ratio prediction. Also, the central composite design of response surface methodology was applied to forecast outputs. A modified cubic model was observed in all responses with high R values (greater than0.9). The drying parameters were optimized for the specified constraints, resulting in 68 °C temperature, 5 m/s air velocity, 900 w microwave power, and 1479 w infrared power. The experimental values were found to be 0.368607 g/s for the moisture removal rate, 7.16988 MJ/kg water for the specific energy consumption, 90.6% for the head rice yield, 58 for the whiteness index, 3.63 for the water uptake ratio, and 2.28627 for the elongation ratio, at the optimum treatment conditions.
本研究旨在探讨红外线（1000-2000 W）和微波功率（100-900 W）、空气速度（1-5 m/s）和温度（40-80°C）如何影响混合干燥器中的比能耗、脱湿率以及产品质量（白度指数、整精米率、吸水率和伸长率）。升高温度、速度和微波功率，降低温度，均可提高稻谷样品的整精米率。实验证明，与单一流化床干燥器相比，新型混合系统可显著提高脱湿率（从 100%提高到 700%）、整精米率（从 5%提高到 40%），并降低比能耗（从 10 降低到 80%）。混合干燥器中干燥样品的吸水率和伸长率高于单一干燥器，但白度指数没有显著差异。最佳干燥条件与最低比能耗以及最高脱湿率和稻米质量有关。实验数据拟合到经验干燥模型中，以解释干燥过程中水分比的变化。Nomhorm 和 vermas 模型被发现是预测水分比的最佳模型。此外，还应用响应面法的中心复合设计来预测输出。在所有响应中都观察到修正后的立方模型，R 值（大于 0.9）较高。在指定的约束条件下，对干燥参数进行了优化，得到的最佳干燥条件为：温度 68°C、空气速度 5 m/s、微波功率 900 W、红外功率 1479 W。在最佳处理条件下，实验值分别为脱湿率 0.368607 g/s、比能耗 7.16988 MJ/kg 水、整精米率 90.6%、白度指数 58、吸水率 3.63、伸长率 2.28627。
