Study On Sludge Drying Mechanism

Sludge is a byproduct of pollution control technology, likely to cause secondary pollution; and high moisture content of sludge, bulky, difficult to stack and transport. Sludge drying can effectively reduce the volume, can be burned as sludge derived fuel processing or pre-means, sometimes you can deal with as a separate measure, therefore, sludge drying, especially the indirect drying of sludge is a current research focus of sludge disposal.Taking from the source of sludge, as well as its harm and status, this article analyses and discusses the treatment methods of sludge at home and abroad, and also the technology to make resource from sludge. The better way to process the municipal sewage sludge is to dry it. Sludge drying at home and abroad were reviewed, and more research is required in sludge drying mechanism and the model, which determines the research content and research direction.Sludge drying is a process of energy consumption, the effect of the thermal conductivity of sludge under different conditions on heat transfer performance of the dryer that cannot be ignored. Using the spherical method for separate determination of the thermal conductivity of sludge in different composition, at different moisture content, at different temperatures, but also determination of bulk density for sludge, lays a foundation for the drying efficiency of sludge.Sludge thermal conductivity and sludge drying rate exists correlation. The study were make on the hollow blade paddle dryer, added the material that potential to improve the thermal conductivity sludge, coal particles, bentonite, quartz sand, quartz sand and bentonite mixture has been separate added into sludge. Then determine sludge drying rate curve, analysis the improvement effect on sludge drying rate under the addition of different material.In a large number of reasonable assumptions, assuming that the drying process of sewage sludge in the same frame structure and the same size, assuming no matter how evaporation process, the water vapor partial pressure is0, establish the transfer model in sludge drying process, and calculate the numerical calculation of single pellet sludge in drying, the results of calculation are consistent with previous experimental data, provides a convenient computational tools for the drying characteristics research of sludge.