Low Cost Municipal Sludge Drying

TDG Holdings Limited (TDG), located in Haining City, Zhejiang Province, was founded in 1984 and is the first listed company held by a natural person in China, with a stock code of 600330 and a registered capital of 588 million yuan. TDG attaches great importance to the development of environmental protection, and has more than ten years of cooperation with Japan Hitachi, Mitsubishi and other companies. From Japan Mitsubishi introduced a full set of sludge "drying + incineration" disposal technology suitable for China's national conditions, to contribute to China's environmental protection cause. Main products: Disc sludge dryer is the sludge drying technology recommended by three national ministries and commissions, and is also the mainstream drying equipment for sludge disposal in developed countries, which is at the world leading level. The disc dryer, compared with other indirect drying equipment has, large heat transfer area, good mixing effect, better promote the evaporation and removal of water and other advantages, is a newly developed improved indirect heating dryer. The rotary dryer is mainly composed of stator (shell), rotor (rotor) and driving device. (1) Rotor rotor center shaft is the bearing part of drying turntable, it is a hollow shaft, all the turntables are welded on this hollow shaft. Each piece of turntable is welded by two pairs of buckled discs. The inner cavity of the center shaft is connected to the inner cavities of all the turntables. In order to improve the sturdiness of the turntables, the inner cavity of the hollow turntable is distributed with many support rods, which support the left and right discs at both ends. Depending on the nature of the material to be dried, the turntables can be made of mild steel, stainless steel, or special alloy steel. On the edge of the turntable is equipped with a propeller/stirrer, which has two functions: one is to propel the conveyed material, and the other is to stir the mixture. The inclination angle of the thrusters is adjustable. The inner cavity of the turntable can be fed with low and medium pressure steam, thermal oil or high pressure hot water to transfer the heat required for drying the product. (2) Stator stator approximate a cylindrical shell, the upper part of the high up, empty space to accommodate the sludge waste steam, and waste steam outlet. The stator end plate is flange mounted for easy access, and the end plate is also used to fix the rotor bearings. In order to facilitate maintenance, the waste steam dome outlet is also equipped with a maintenance cover. (3) Drive motor The entire drive unit consists of an embedded reduction gearbox, belt drive, coupler and motor for driving the rotor to rotate slowly. (4) Propeller/Stirrer Rotary Dryer Function By the action of the propeller/stirrer on the edge of the rotor, the sludge is transported uniformly and slowly through the entire dryer and is dried by thermal contact with the rotor. During the drying process, hot steam condenses on the inner wall of the rotary chamber, forming condensate. The condensate is directed through a tube into a center tube and eventually out of the dryer through an export chute. Between each of the two discs a scraper is fitted, which is fixed to the housing (stator). The scraper loosens the sludge between the discs and allows the waste steam to leave the sludge quickly. The heat transfer medium of the dryer is generally 0.2Mpa ~ 0.6Mpa saturated steam. Characteristics of rotary dryer: (1) Contact drying (indirect drying, no direct contact between heat transfer medium and sludge) (2) The final drying degree of sludge can be flexibly varied according to customer's requirements, such as reducing the moisture content of sludge from about 80% to 40%, 30%, 20%, 10% and 5%. (3) Suitable for all sludge disposal options (incineration, landfill or fertilizer) (4) Low oxygen content in the system, eliminating the possibility of dust explosion (6) High sludge load in the machine, even if the feed is not uniform, to ensure smooth operation (7) Large load, easy to control (8) Strong construction and durability (9) Low rotor speed of 4-5 rpm, low wear and tear (10) Very well designed. (9) low rotor speed, 4-5 rpm, small wear and tear (10) very compact design, but the heat transfer area is very large, the equipment occupies the smallest area and plant space compared with other dryers (11) less maintenance, good continuity of operation, can be operated around the clock to ensure that the annual operation of 7,200 hours (12) electricity consumption (13) power outages can be started in case of emergency, stable operation (14) drying equipment, completely sealed, less odor generation, good working environment (15) high market share