| 摘要 |
PURPOSE: Provided are a method and an apparatus for drying sludge by stepwise moisture reduction processes, so moisture content of sludge finally becomes almost 0%. CONSTITUTION: The method comprises the steps of pumping and transporting sludge from a sludge tank(110) with a pump(120); pressing and heating the sludge with a screw conveyer being comprised of a cylinder having a band heater at the circumference thereof and a transporting screw in the cylinder at a temperature in the range of 250 to 350 deg.C for 4 to 6 minutes, thereby reducing moisture content of the sludge to be 55 to 65%; dispersing and heating the sludge lump with moisture content of 55 to 65% with at least two dispersing rollers, each having heat medium circulating therein and being rolled, thereby reducing moisture content of the sludge lump to be 25 to 35%; compressing and heating the sludge with moisture content of 25 to 35% using a screw conveyer being comprised of a transporting screw and a cylinder with a hot air circulation duct at the circumference thereof, thereby reducing moisture content of the sludge to about 0%; and crushing the sludge lump to powders. The apparatus comprises a pressing and heating device(200) with a heating hopper, a cylinder, a screw installed in the cylinder and a motor, and a band heater attached to the circumference of the cylinder for heating sludge; a dispersing and heating device(301) with a cylinder with an upper end from which sludge lump is introduced thereinto and a lower end through which the sludge lump is discharged, a plurality of dispersing rollers in which heating media circulates and which is installed in perpendicular to the length of the cylinder and has both ends coupled to a wall of the cylinder, and a driving unit for rotating respective shafts running through the dispersing rollers; a pressing and hot air heating device(400) with a hot air heating hopper, a cylinder for pressing sludge while the sludge is transported, a screw installed in the cylinder for transporting the sludge, and a hot air circulation duct formed at the circumference of the cylinder; and a sludge crusher(500) with a crushing cylinder, a driving unit for rotating a shaft, the shaft running through the crushing cylinder, and a plurality of blades fixed to the shaft. |
