SU361983A1 - METHOD OF BURNING DRAIN SEDIMENTATION - Google Patents

Description

one

The invention relates to the field of sludge treatment of municipal and industrial wastewater.

A known method of incineration of sewage sludge after their mechanical dewatering on vacuum filters, centrifuges or filter presses involves burning sludge in a fluidized bed of an inert carrier, the pre-drying of the sludge takes place in the bed, and incineration in the furnace above the bed. Heat from the exhaust gases is used to preheat the air supplied to the furnace.

The disadvantages of this method are the saturation of the furnace space with moisture vapor, the need to use an inert carrier, fly ash from the kiln, the possibility of furnace sintering, which reduces the efficiency of the process.

To intensify the process, it is proposed to dry the precipitate after mechanical dehydration to a moisture content of 5-40% with simultaneous grinding and subsequent classification, after which the precipitate with a particle size less than 500 microns is burned in a cyclone furnace, and with a particle size greater than 500 micron it is returned to drying.

Example. The sediment of the Lublin aeration station with 95% moisture content of organic matter is incinerated

60% by weight of dry matter sediment. The precipitate is first dewatered on a drum vacuum filter with a converging web to a moisture content of 80%. Dehydrated sediment on tape

conveyors and screw feeders are fed successively to the dryer, made in the form of a tubular element, where in countercurrent streams of flue gases with a temperature of 600-660 ° C and a pressure of 1.2-1.3 atm. happens

drying the precipitate to a moisture content of 15-20% and its grinding to 300-500 microns. The dried precipitate is classified according to size in an air-through baffle. As a result of the classification, the precipitate is divided into two streams. Sludge particles with a particle size of more than 500 µm, constituting 30% of the weight of the dried sludge, are returned for re-treatment to the opposite gas jets, and particles less than 500 µm constituting 70%

by weight of dried sludge, after separation

from the gas stream carrying them in a cyclone-type dust precipitator are sent for incineration

in a cyclone firebox.

The burning of the pulverulent sediment in the cased state is carried out in a cyclone furnace with a pressure of 1.4-1.5 atm in it and a temperature at the outlet of the furnace 950-1000 ° C.

The flue gases after dilution with cold air in the cooling chamber to 600-650 ° C

at a pressure of 1.2-1.3 atm, they are used for 3 drying and grinding the sludge dried on a vacuum filter. Ash is removed from the cyclone furnace in the form of a melt. The subject of the invention is a method of incineration of sewage sludge, including mechanical dewatering and drying of sludge using heat gases, 4 exhaust gases from incineration, characterized in that, in order to intensify the process, sludge is dried to a moisture content of 5-40% with simultaneous grinding and subsequent classification, after which the sediment with a particle size of less than 500 microns is fed into a cyclone furnace for burning, and the sediment with a particle size of more than 500 microns is returned for drying.