冷冻对脱水污泥干燥与燃烧特性的影响

为了研究冷冻对脱水污泥干燥与燃烧特性的影响,考察了不同冷冻温度对污泥干燥效果的影响.利用同步热重分析仪(TG-DTA)研究了不同冷冻温度和升温速率对脱水污泥燃烧特性的影响,并进行了污泥燃烧动力学分析.结果表明:与原泥相比,冷冻将脱水污泥变成了可进行破碎的硬质结构,当温度降到-20℃时,破碎污泥的干燥速率提升了41.46...

Effect of freezing on drying and combustion characteristics of dewatered sludge

This work explored the effect of freezing operation on the drying and combustion characteristics of dewatered sludge and different freezing temperatures on the characteristics of the drying process for the sludge. In addition, the effect of different freezing temperatures and heating rates on the combustion characteristics of dewatered sludge were investigated by thermogravimetric analysis (TG-DTG). Then the dynamics analysis was carried out. The results indicated that compared with the original sludge, freezing turned the dewatered sludge into a hard structure that can be crushed, and when the temperature was dropped to –20℃, the drying rate of the crushed sludge was improved by 41.46%, and the drying time was shortened by 41.67%. Three degradation stages, dehydration, combustion of volatile and combustion of the fixed carbon were identified in the combustion process of the freezing dewatered sludge. As the temperature decreased, the ignition point, the volatile releasing index, the flammability index, the burnout index, and the general combustion index increased. According to the dynamics analysis, the reaction order of pre-peak was 0.9 and post-peak was 1.1. The apparent activation energy of the frozen sludge was higher than that of the original sludge, and as the temperature decreased, the apparent activation energy would decrease.