污泥干燥及气体释放特性研究

Study on Sludge Drying and Gas Release Characteristics

采用污泥薄片模拟分散态污泥干化过程,研究了干化风速、温度对污泥干燥速率的影响,并分析了污泥干燥过程中的形貌变化,采用热红联用分析污泥在(35～700℃)干化过程中气体的释放情况。结果表明:污泥干燥过程中的自由水、空隙水和吸附水干燥速率不同,提高干燥温度和热风风速,污泥干燥速率增大;污泥体积的收缩主要由于自由水的蒸发,粘滞区的存在是由于自由水蒸发完毕而引起干燥速率发生突变;污泥升温过程中释放的气体主要有CO2、H2O、NH3、VFA及庚烷,273.75～333.76℃的温度区间为失重速率最大区域;VFA在273.75℃释放量最大,庚烷在333.76℃释放量最大。

With the drying process of sludge wafer to simulate the drying process of dispersed sludge, the influence of drying gas speed and temperature on sludge drying rate and the morphology changes was investigated. Gas release characteristics have been studied by using TG-FTIR in sludge drying process （35-700℃）. The results show that： The drying rate of free water is different from the ones of interstitial water and adsorbed water in the drying process. The drying rate increased with the raising of drying temperature and hot air velocity. The volumetric systole is primarily due to the evaporation of free water, the presence of viscous zone is due to drying rate suddenly changed caused by the evaporation of the free water is complete. It release gas mainly of water, carbon dioxide, ammonia, volatile fatty acid and heptane, the temperature range of 273.75-333.76℃is the area of maximum weight loss rate . The emission of VFA is maximum at 273.75℃, and heptane at 333.76℃.