不同形状污泥干燥特性的差异性及其成因分析

通过对100~300℃恒速干燥条件下饼状污泥和球状污泥的失重速率、干基质量变化的测定,系统分析了不同形状污泥干燥特性的差异及造成这种差异的原因.结果表明,饼状污泥在干燥过程中会产生裂缝,并分裂成若干小块,而球状污泥仅仅会产生体积收缩,形状并未发生变化.由于表观形态变化的差异,导致了污泥干燥过程的差异,饼状污泥的干燥过程分为升速和降速2个阶段,而球状污泥的干燥过程则分为升速、恒速和降速3个阶段;饼状污泥的平均干燥速率大于球状污泥.在150℃以上干燥时,饼状污泥的有机物在水分蒸发的同时即开始分解,而球状污泥则在水分蒸发完后才开始发生有机物分解.

Difference and cause analysis of drying characteristics of different shapes sludge

Through determination of weight loss rates and dry basis change of cake sludge and spherical sludge dried at 100~300℃, differences of drying characteristics of the two kinds of sludge were analyzed. Cake sludge cracked and split into several small pieces, while spherical sludge only shrank without shape change. Different apparent change led to different drying process. Cake sludge drying process was divided into two stages:acceleration stage and deceleration stage, while spherical sludge drying process was divided into three stages: acceleration stage, constant speed stage and deceleration stage. The average drying rate of cake sludge was bigger than spherical sludge. When dried above 150℃, organic matter of cake sludge began to decompose with water evaporating, while organic matter of spherical sludge didn’t decompose until most of water evaporated.