Drying Technology
Key words:sludge disposal technology ,Urban Wastewater Treatment
Sludge sanitary filling
Burial is currently the most used sludge disposal technology, but this disposal technology.The technique will contaminate the soil. Sludge drying and incineration technology can process large.It is a high-efficiency sludge disposal method at present. Effective technical means 13l. "Technical Guidelines for Sludge Treatment and Disposal in Urban Sewage Treatment Plants""South" pointed out [4l, when sludge is incinerated alone, drying and incineration should be combined to improve the thermal energy utilization efficiency of sludge. In recent years, with the drying technology.The continuous optimization of technology and incineration technology and the maturity of the second technology, sludge drying and incineration.Burning technology has made great progress [5,6. , and this technology also has some typical program application. In this paper, the mainstream application technologies of sludge drying are reviewed.And the typical sludge drying and incineration process in my country is analyzed.
Advances in Sludge Drying and Incineration Technology
Before entering the incinerator, the wet sludge is processed by a dryer to a moisture content.Lower drying sludge, the heat medium heats the wet sludge to evaporate its water into dry sludge. The solid content of the dried sludge will directly affect the subsequent incineration.The burning system will affect the effect of the entire sludge treatment and disposal. At present, most of the sludge drying adopts indirect heating drying technology.
The moisture content of the received sludge is 80%, the total processing capacity of the system is 400t/d, the moisture content of the treated wet sludge is 80%, and the high calorific value of the designed dry basis is 13,086kJ/kg. Chemical machine + bubbling incinerator treatment technology 19], set up two drying incineration lines wet sludge enters the feed port of the thin layer dryer through the conveying system, the sludge is carried by the rotor to the surface of the hot wall, and the paddle on the rotor The leaves mix the sludge on the hot wall surface repeatedly, and the sludge is conveyed to the discharge end through the screw. On the steam side of the dryer, the 6bar saturated steam generated by the waste heat boiler heats the sludge through the dryer jacket, and the water content of the heated sludge decreases due to water evaporation. After drying, the wet sludge with a moisture content of 80% is dried into dry sludge with a moisture content of 30% and a temperature of about 100°C. The dry sludge is sent to the incineration unit through the conveying system. The sludge stays in the dryer for a very short time, and the sludge in the dryer can be completely discharged by the inertia of the rotor of the dryer. The carrier gas generated during the drying process moves in the opposite direction of the sludge, and is fed by the sludge. The steam pipe above the port is discharged, and then the carrier gas is condensed, the condensate is sent to the sewage treatment plant for treatment, and the non-condensable gas is discharged after treatment.
The dryer is an important equipment in the sludge drying and incineration system, and its performance has a great influence on the stable operation and operating efficiency of the entire system. In the existing mature technology, different dryers and incinerators have their own advantages and disadvantages. feature. There are many technologies for sludge drying. In a specific project, a suitable drying system should be selected according to various factors such as sludge quality, operating conditions, discharge requirements, and site requirements. At present, the development of domestic sludge drying and incineration technology is in its infancy, and the sludge composition of municipal sludge and industrial sludge is unstable, resulting in many engineering construction and operation problems in existing sludge disposal projects. With the gradual increase of sludge drying and incineration projects and the accumulation of engineering design experience and operation experience, sludge drying and incineration technology will have greater development in China.
