Patent DE-102012201846-A1 (DE)
Title: Drying sludge, comprises e.g. applying sludge on bottom of drying room, pre-drying the sludge, incorporating portion of pre-dried sludge into heated thermal dryer, drying sludge, discharging sludge and conveying ambient air into drying room
Inventor: BUX MARKUS
IPC: C02F11/13
Filed: 2012-02-08
Abstract: Drying the sludge, comprises (a) applying the sludge with 15-30% dry matter on a bottom of a drying room (10), (b) pre-drying the sludge, and thoroughly mixing the sludge, (c) incorporating at least a portion of the pre-dried sludge into a heated thermal dryer (12), (d) drying the sludge in the thermal dryer, and discharging the sludge, (e) passing air (14) or water vapor through a first region of a heat exchanger, passing an ambient air (16) or water or further liquid medium into a second region, and (f) conveying the ambient air or water or further liquid medium into the drying room. Drying the sludge, comprises (a) applying the sludge with 15-30% dry matter on a bottom of a drying room (10) or the drying room optionally comprises the sludge, (b) pre-drying the sludge in the drying room, and thoroughly mixing the slurry, (c) incorporating at least a portion of the pre-dried sludge into a heated thermal dryer (12), where the respective sludge introduced into the thermal dryer, is replaced by the sludge present in the drying room by carrying out the step (a), and then carrying out the step (b), (d) drying the sludge in the thermal dryer to obtain 80-95% dry matter, overflowing or passing the sludge through air absorbing moisture content from the sludge, heating the sludge, to release the water vapor from the sludge, and discharging the sludge after reaching 80-95% dry matter, from the thermal dryer, (e) passing air (14) or water vapor heated in the step (d), through a first region of a heat exchanger, passing an ambient air (16) or water or further liquid medium into a second region, condensing the moisture present in the air or water vapor to emit heat at the ambient air or water or other liquid mediums, where ambient air or water or other liquid mediums are heated not > 50[deg] C, preferably not > 40 K above an ambient temperature, and (f) conveying the ambient air or water or further liquid medium heated in the step (e) into the drying room by injecting, for pre-drying, such that the ambient air flows on or above the surface of the sludge applied on the bottom of the drying room, or the water or further liquid medium flows through at least one heating line present in the bottom of the drying room, and is heated by the bottom. An independent claim is also included for an apparatus for performing the above method, comprising: a drying room with a device for mixing the sludge applied on the bottom of the drying room; a heated thermal dryer with a belt conveyor for continuously transporting the slurry through the thermal dryer; a heat exchanger, which comprises (i) the first- and second region, where the heat exchange takes place between the first- and the second region, (ii) a first line, which connects the first region, preferably vapor- or air deflector end with the thermal dryer, (iii) a second line, which connects the second region with the ambient air deflector end, and (iv) and a third line, which connects the second region with the drying room; and at least one device for conveying the vapor- or air and the ambient air into the first-, second- and third line.