城市生活垃圾组分低温干燥特性及模型研究

对典型城市生活垃圾组分（废纸板、纺织物、瓜果皮和竹木）进行低温干燥实验,研究其在不同温度（40、50、60、70和80℃）下的干燥曲线、薄层干燥模型、有效水分扩散系数和干燥活化能,并构建了低温干燥模型.结果表明,各组分的干燥速率随温度升高不断增加,但增加的幅度逐渐下降;Modified Page模型能准确地描述4种组分水分比〉25%时的干燥特性;通过Fick第二定律求得废纸板、纺织物、瓜果皮和竹木这4种垃圾组分的有效水分扩散系数,其值分别为8.24×10-8～23.67×10-8、7.73×10-8～12.56×10-8、3.57×10-8～14.18×10-8和6.51×10-8～23.84×10-8m2.s-1;通过Arrhenius方程获得4种垃圾组分水分扩散的活化能依次为25.26、10.75、32.16和29.49 kJ.mol-1;对实际生活垃圾进行相似的干燥实验,发现Modified Page模型也可以很好地模拟实际生活垃圾的干燥过程,计算得到其有效扩散系数为6.78×10-8～18.65×10-8m2.s-1,干燥活化能为22.36 kJ.mol-1.

Study on the Low Temperature Drying of Components of Municipal Solid Waste and Its Model Analysis

The drying behaviors of four typical municipal solid waste (MSW) components (including waste paper, textile, pericarp and wood) were studied under low temperature. Effects of temperature on drying characteristic, thin layer drying models, effective moisture diffusion coefficient and activation energy were investigated in this paper. Experimental results showed that with increasing temperature, the drying rate increased, but the added value reduced gradually. Four mathematical models were used to simulate drying curves of MSW components. Modified Page model was found to give better predictions when moisture content was more than 25%. Based on the Fick's second law, the effective moisture diffusion coefficient for waste paper, textile, pericarp and wood were 8.24×10^-8-23.67×10^-8, 7.73×10^-8-12.56×10^-8, 3.57×10^-8-14.18×10^-8 and 6.51×10^-8-23.84×10^-8 m²·s^-1. The activation energy determined through Arrhenius equation were 25.26, 10.75, 32.16 and 29.49 kJ·mol^-1, respectively. Carried on the similar dry experiments to practical MSW, It was found that Modified Page model was also suitable for simulating the drying process of practical MSW, its effective moisture diffusion coefficient and activation energy were 6.78×10^-8-18.65×10^-8 m²·s^-1 and 22.36 kJ·mol^-1, respectively.