烟秆颗粒的微波干燥动力学与能耗分析

Microwave Drying Kinetics and Energy Consumption Analysis of Tobacco Stem Particles

为了更优地设计烟秆颗粒的微波干燥设备,开展了烟秆颗粒微波干燥过程中的装载量、微波功率对干燥时间、干燥速率及单位能耗等影响的试验,采用了微波工作频率为2 450MHz、输出功率为0.7k W的微波干燥设备,对装载量范围为33~169g的烟秆颗粒进行干燥。结果显示:干燥过程为升速、恒速与降速3个阶段,恒速阶段时间较长。采用了5种干燥数学模型对试验数据进行非线性回归拟合求解,通过比较决定系数、残差平方根,发现Logarithmic模型是表达烟秆颗粒微波干燥的最优模型,其干燥系数k随着装载量的增大而减小。在装载量为33~169g时,通过提高装载量能够高微波干燥效率(8.21%~22.12%),同时降低单位能耗(15.45~39.25MJ/kg)。

In order to better design the microwave drying equipment of tobacco stem particles,the test carried out the effects of materiel load and microwave power on the drying time,drying rate and unit energy consumption in the microwave drying process of tobacco stem particles. Microwave drying equipment with microwave operating frequency of2450 MHz and output power of 0. 7k W was used for drying tobacco stem particles with a loading range of 33-169 g.The results showed that the drying process is three stages： rising speed,constant speed and falling speed and constant speed stage was longer. Among the 5 mathematical models used to fit the drying process of tobacco stem particles,through the comparison on the R^2,SSE between experimental and predicted moisture ratios,it was found that the Logarithmic model was the best one for all the data points. The value of the drying coefficient k decreased with the increase in the material load. Energy consumption decreased and drying efficiency increased with the increasing of material load of tobacco stem particles. Average specific energy consumption and drying efficiency varied in the range of 15. 45 - 35.25MJ/kg and 8. 21% - 22. 12%.