二段式污泥低温干化的原理与水汽热量平衡

Two-stage low-temperature drying of sludge:Mechanisms and vapor/heat balance

在深入研究污泥成分和通过模拟实验分析污泥干化特性的基础上,首次建立了利用烟气余热的二段式污泥低温干化技术,同时给出了该技术的工作原理和计算了污泥干化过程的水汽、热量、物料平衡.结果表明,利用烟气余热的二段式污泥低温干化技术不仅能在不增加新能耗的情况下使污泥得到有效地干化,而且能使污泥自然形成质地坚硬并保存原始污泥90%以上热值的颗粒;污泥干化成粒装置内的螺旋板、扬料板和链锤等辅助设备可以明显提高污泥干化效率;烟气量为1.5×105m.3h-1,烟温为155℃,经污泥干化后降温50℃,可使100.td-1污泥从含水率78%干化至40%.这为污泥的无害化、减量化、资源化处理提供了理论依据和技术支撑,对开辟以废治废和废弃物循环利用的污泥处理新途径具有重要的实践指导意义.

A new two-stage low-temperature drying technique utilizing flue gas waste heat from a power plant has been developed based on studies of the characteristics of the sludge components and drying processes.The new technique removes moisture from sludge at low temperature to maximize the heat value contained in the dried sludge.It also uses auxiliary equipment such as spiral flights,tossing plate,and chain hammer,to significantly improve the efficiency of drying process and granulation.The new technique not only effectively dries sludge（moisture content reduced from 78% to 40%）without new energy but also causes the sludge to form hard particles that retain more than 90% of the original heat value.With a flue gas volume of 1.5×10^5 m3·h^-1 at a temperature of 155 ℃,100 tons of sludge can be dried per day using the new technique.The temperature of the used flue gas will decrease to 50 ℃.This paper also presents a thorough analysis of the mechanism and the vapor/heat balance of the new drying technique,which could provide a theoretical basis and technological support for reducing sludge and making it harmless and reusable.