Working principle and design description of box type sludge dryer

The box type sludge dryer mainly uses hot air to pass through the wet sludge surface to achieve the purpose of drying. When hot air passes through the surface of sludge, it is called horizontal airflow chamber drying; when hot air passes through sludge vertically, it is called cross flow chamber drying. Because the material is in a static state when drying, it is necessary to pay attention to the selection of relative flow direction of air and sludge in the design of box type sludge dryer, so as to achieve the effect of drying evenly.

Generally, the box type sludge dryer is intermittent operation, which is widely used in sludge with low humidity and domestic sludge. It may also be used for drying industrial sludge.

Usually, the sludge is manually put into the drying chamber, or placed on a trolley into the chamber. The structure and size of the trolley shall be determined according to the drying medium circulation mode of sludge.

Hot air and flue gas are usually used as drying medium. In the design of dryer, there should be a certain amount of air circulation to reduce the temperature drop of air at the inlet and outlet. In this way, the moisture content of sludge can be more uniform in the width of the pile row at the same temperature drop.

In order to improve the drying intensity and reduce the cost of the box type sludge dryer, most of them start from increasing the air speed and improving the design structure. However, a prominent problem in the operation of the box type sludge dryer is uneven drying, because it is an unstable drying. Due to the continuous change of drying conditions, the drying degree of the same section is different.

Due to the small drying capacity of the box type sludge dryer, the large-scale sludge drying equipment of real energy-saving company can be selected for large-scale treatment, and the daily sludge drying capacity can be hundreds of tons!

Box type or tunnel type sludge dryer usually puts the dried sludge materials on the trolley for drying. The trolley can be designed with different structure and size according to the shape of the sludge material to be dried and the circulation direction of the drying medium.