Sludge drying technical knowledge

Biochemical sludge due to a large quantity of soil, the way, the disposition is always a difficult problem. There are a variety of sludge treatment technology in the world at present, generally can be divided into two categories: one category is the incineration, another kind is dry. Because the sludge incineration need large investment, high operation cost, high energy consumption, so no special requirements, generally do not use direct incineration method.

At present there are hundreds of sludge drying device put into application, were used in the technology and equipment abroad. Drying technology in China has just started. Considering the sludge drying investment, energy consumption and environmental protection, security, reduction requirements, combined with the characteristics of the project and after drying of the final disposal of sludge, the sludge drying device with adjusting the SEVAR margin big band and high drying process, the moisture of sludge drying rate after 10% ~ 35%, after drying and then sent to the out of bounds on biochemical sludge incineration.

The moisture content of dewatered sludge about 85% by the hydraulic device continuously from the hopper output, biaxial mixer drying system through screw conveyor and sludge pump input, mixing and drying sludge mixed, the mixed solid containing rate is about 25% of the sludge after distribution device and later to the noodle machine, sludge by extrusion noodle machine, form a strip of sludge (6mm in diameter ), and then input to the dryer, 75% moisture content of sludge water evaporation process completed in the dryer, the dryer out of the sludge solid content is about 65%, when necessary, through adjusting, fixed rate is about 90% containing sludge. A portion of dry sludge by the screw conveyor to the mixing system, the remaining portion of the dried sludge by the screw conveyor to stem a mud bucket loading sinotrans.

Dry areas drier is composed of 5 independent drying module, each module in the dry gas by medium pressure steam heating, drying gas flow through a direct heating the sludge mud, complete the evaporation process to realize.

The gas formed by evaporation of the high temperature and high humidity ( 75-80° C ), the module from the dryer after discharge, through the heat exchanger and condenser after the evaporation of the water condensed, the condensed water is drained to the waste water treatment unit, the process gas mostly in internal circulation system, a small amount of gas is only equivalent to the amount of gas and vapor emitted part of the negative pressure suction by suction fan from the dryer out to waste gas biological filter, after treatment discharge standards. Residual air preheated to a desiccator, become the circulation process gas.