热风系统对食品工业污泥生物干化的影响

Influence of thermal ventilation system on biodrying of sludge in food industry

通过预热+热通风模拟工业余热对食品工业脱水污泥进行联合热处理,研究其在不同热通风(30,40,50℃)条件下生物干化效果和机理.结果表明,预热基础上热通风40℃时生物干化高温期可维持62h(>45℃)且每日累积温度TD为15.77℃/d,干化周期166h后物料含水率从68.95%下降至41.28%.三维荧光光谱分析表明初始物料中有机质以酪氨酸为主,TC由生物干化前的243.6~243.8g/kg WM下降至生物干化后的182.9~191.7g/kg WM,主要以CO_(2)的形式分解最终以腐殖酸的形式稳定存在,TN在整个过程中变化不大,NH_(4)^(+)-N从0.867~0.877g/kg WM下降至0.43~0.55g/kg WM,生物干化过程中NO_(3)^(-)-N含量较低,最终含量保持在2.94~6.54mg/kg WM.能量平衡和产物燃料特性分析结果表明,预热基础上热通风至40℃时用于水分蒸发的能量利用效率最高,占总消耗热量的85.34%,得到的产物具有最佳的燃料特性指数(75.52).

The combined heat treatment of dewatered sludge in food industry was carried out by preheating and thermal ventilation to simulate industrial waste heat.The biodrying effect and mechanism of dewatered sludge were studied under different thermal ventilation conditions(30,40,50℃).The results showed that the high temperature period of biodrying can be maintained for 62h(>45℃)at 40℃of thermal ventilation based on preheating and the daily cumulative temperature TD was 15.77℃/d.The moisture content of the material decreased from 68.95%to 41.28%after 166 h of biodrying period.Three-dimensional fluorescence spectrum analysis showed that the organic matter in the initial material was mainly tyrosine.TC decreased from 243.6~243.8g/kg WM before biodrying to 182.9~191.7g/kg WM after biodrying,mainly decomposed in the form of CO_(2)and finally stable in the form of humic acid.TN changed little in the whole process,and NH_(4)^(+)-N decreased from 0.867~0.877g/kg WM to 0.43~0.55g/kg WM.In the process of biodrying,NO_(3)^(-)-N content was low,and the final content remained at 2.94~6.54mg/kg WM.The analysis results of energy balance and fuel characteristics of product showed that the energy utilization efficiency of water evaporation was the highest when the thermal ventilation reached 40℃based on preheating,accounting for 85.34%of the total heat consumption.The obtained product had the best fuel value index(75.52).