餐厨垃圾的微波干燥特性及动力学模型

Microwave drying characteristics and kinetic model of food waste

为了探索餐厨垃圾有效干燥的新途径,对餐厨垃圾进行了微波干燥试验,并建立了微波干燥的动力学模型.试验表明,微波干燥具有显著的节能效果,同样的装载量,微波干燥的能耗不足电热干燥能耗的10%.微波功率与装载量都对干燥特性影响很大,选择恰当的装载量与微波功率既能保证干燥的质量,又可降低干燥单位质量垃圾的能耗.动力学分析表明,建立的动力学模型能较好地描述餐厨垃圾的微波干燥过程,拟合相关系数均大于0.94.餐厨垃圾干燥的活化能为16.00 kJ/mol左右、物质获得非热效应能以及指前因子的增大,是微波加快干燥速率的主要原因.微波使干燥过程的反应级数n增加,而增大微波强度又有降低反应级数n的作用,非热效应能占比系数?可能与物质的结构、种类、体积等因素有关.

To investigate a new way to effectively dry the food waste, the microwave drying was proposed and the kinetic model for microwave drying of food waste was established in this study. Experimental results showed that compared with electric heating drying, microwave drying had significant energy saving effect, whose energy consumption was less than 10% of the energy consumption of electric heating drying, with equal loading quantity. Microwave power and loading quantity had great influence on the drying characteristics, and choosing appropriate loading quantity and microwave power can ensure drying quality, as well as effectively reduce the energy consumption of drying unit mass food waste. The kinetic analysis indicated that the kinetic equation described the microwave drying of food waste, and all fitting correlation coefficients were above 0.94; the activation energy of food waste drying was about 16.00 kJ/mol. Obtaining non-calorific effect energy and increasing the pre-exponential factor were main reasons of microwave accelerating the drying rate of food waste; microwave made the reaction order n increased, but n can be decreased by increasing the microwave radiation intensity; the proportion ,β of non-calorific energy to the total microwave energy may be related to material structure, kind and volume.