导向管喷动床小麦干燥工艺优化研究

    Technology optimization of drying wheat by spouted bed with draft tube

    • 摘要: 为在国内推广使用具有良好的传热和传质效果的喷动床,自行设计制造了喷动床粮食干燥机,以探索喷动床用于粮食干燥的实际效果和所存在问题的解决方法。喷动床的内径为180 mm,高为700 mm,锥体部分高为100 mm,锥角为90°,气体入口管内径为25 mm,所用导向管的内径为25 mm,长200 mm,距进气管口54 mm。以湿小麦为原料,进行喷动干燥试验。设计了三因素三水平正交试验方案。所考察的三个因素是空气流量、热空气温度和湿麦装料量。各因素的水平为:空气流量取42、54、71 m3

       

      Abstract: For spreading the use of spouted bed in China, which has good effect on heat and mass transfer ,a spouted bed grain dryer was designed and fabricated to study its effect on drying grains. The structural parameters were as follows: inner diameter was 180 mm, height of bed 700 mm, height of cone 100 mm, conic angle 90°, inner diameter of gas inlet tuber 25 mm , and its length 200 mm. A series of experiments of drying wet wheat were carried out with the spouted bed. A scheme of orthogonal test, which includes 3 factors and 3 levels, was designed. The factors were the air flow rate, the temperature of hot air and the load of wet wheat. The levels of the air flow rate were 42, 54, 71 m3/h(20℃,101.3 kPa);the temperature of hot air were 60, 75, 90℃; the load of wet wheat were 2.0, 2.9, 3.8 kg. Taking the heat consumption per kilogram water as the appraising target, the technological parameters were optimized. The optimum conditions on the present apparatus were as follows: the air flow rate was 42 m3/h, the temperature of hot air was 75℃,and the load of wet wheat was 3.8 kg. The optimum heat consumption per kilogram water was 5 588 kJ. The temperature of hot air was the prominent factor. By the studies, the optimum result was obtained for drying wet wheat using the spouted bed dryer with a draft tube. Further research is necessary to enlarge spouted bed dryer to fit drying of grains in industrial scale.

       

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