FIELD: waste treatment.
SUBSTANCE: invention relates to a method for obtaining products of thermal destruction of sludge deposits of urban wastewater. The method includes preliminary placement of sludge in the cavity of the storage hopper, displacement of ambient air oxygen from the locations of the sludge of urban wastewater, its transportation and supply to the cavity for thermal destruction. The method also includes thermal degradation and subsequent separation of thermal degradation products into a gaseous mixture and a solid fraction by means of a group cyclone. The products of thermal destruction of sludge deposits are obtained using a storage hopper, a screw conveyor, a centrifugal impact mill and a group cyclone, which communicate with each other in such a way that the output of the storage hopper is connected with the input of the screw conveyor, the output of the screw conveyor is connected with the input of the centrifugal impact mill, and the output of the centrifugal impact mill is connected with group cyclone inputs. At the same time, sludge deposits of urban wastewater with a humidity of 8-20% and with particle sizes of 0.2-0.4 mm is used. The storage hopper is formed by a hopper, a hopper cavity, a rotary feeder, a discharge pipe, a feeding screw conveyor with an adjustable electric drive, a horizontal hollow housing with a screw, a flue gas supply pipe and a loading neck. The screw conveyor is made in the form of an external housing with an external cavity, an upper section, a middle section and a lower section, placed horizontally. In this case, the middle section is placed under the upper section and above the lower section. Preheating of the sludge is carried out up to 50-80°C when it is fed into the hopper cavity by feeding flue gases under an excess pressure of 0.2 bar into a horizontal hollow housing with a screw. At the same time, the oxygen of the ambient air is displaced from the hopper cavity and replaced with a mixture of flue gases. The steel elements of the screw conveyor, which are designed for direct contact with the sludge deposits of urban wastewater, are heated to 310-340°C by continuous supply of flue gases with a temperature of 340-380°C into the external cavity. A temperature of 800-810°C is created in the cavity for thermal destruction and the chamber wall, then the sludge deposits of urban wastewater are heated by transferring heat energy to it through heat transfer from the steel elements of the screw conveyor heated to 310-340°C, which are brought into direct contact with the sludge deposits. Simultaneously with this heating, the sludge is mixed and moved by means of an upper screw with an upper pipe and an upper spiral, a middle screw with a middle pipe and a middle spiral, a lower screw with a lower pipe and a lower spiral. The humidity of the sludge deposits of urban wastewater is decreased to 2.4-2.8, wt. %, in a screw conveyor. Moreover, the diameters of the upper spiral, the middle spiral and the lower spiral are made and placed relative to each other in such a way that the diameter of the middle spiral is larger than the diameter of the upper spiral, but smaller than the diameter of the lower spiral. At the same time, the middle screw with the middle pipe and the middle spiral is rotated at a lower speed compared to the rotation speed of the upper screw with the upper pipe and the upper spiral, but at a higher speed compared to the rotation speed of the lower screw with the lower pipe and the lower spiral. To carry out thermal destruction, a centrifugal impact mill is used, which is made in the form of a node for receiving and subsequent spreading of sludge from urban wastewater, a chamber with a chamber wall, an annular groove and a cavity for thermal destruction. The node for receiving and supplying sludge from urban wastewater is made in the form of an electric drive, a spreading horizontal disk, a vertical drive shaft, one end of which is connected to the electric drive, and the other to the spreading horizontal disk. The spreading horizontal disk is installed relative to the annular groove in such a way that the sludge is fed into the cavity for thermal destruction from the upper area of the spreading horizontal disk and the upper area of the annular groove, and the removal of thermal destruction products from the cavity for thermal destruction is carried out from under the spreading horizontal disk and the lower area of the annular groove. In this case, the section of the chamber wall, which is placed opposite the sludge being spread, is made concave. At the same time, the sludge deposits of urban wastewater are mechanically destroyed into smaller fragments due to collision with a heated concave section of the chamber wall and heating as a result of the transfer of thermal energy from the heated concave section of the chamber wall and the heated gaseous mixture placed in the cavity for thermal destruction.
EFFECT: invention simplifies the method for obtaining products of thermal destruction of sludge deposits of urban wastewater, as well as improving the efficiency of heat transfer.
1 cl, 10 dwg
