Anhydration and incineration processing method for wet sludge

Abstract

The invention discloses a wet sludge drying and incineration processing method, relating to the technology of waste disposal. Wet sludge with the water content of 60 percent to 90 percent is incinerated in an incinerator of a circulating fluidized bed and a heat exchanger is arranged in a tail flue and is communicated with a heat release coiled pipe arranged in a fluidized bed type sludge drier. Heat exchange media in the heat exchanger and the heat release coiled pipe absorb heat from flue gases of the tail flue and release heat in the sludge drier; the wet sludge to be incinerated is firstly put into the sludge drier and dried to form the dry sludge with a water content of 5 percent to 25 percent, and then the dry sludge is sent into a firing space for incinerating at a temperature of 850 DEG C to 900 DEG C; exhaust gas discharged from the sludge drier is led into the lower part of the firing space as secondary air. The method of the invention has possibly simple technology and reclaims heat generated by the incineration of the sludge as far as possible, thereby incinerating and processing the wet sludge with low energy consumption and low costs.

Description

technical field [0001] The invention relates to the technical field of waste treatment, in particular to a wet sludge incineration treatment method. Background technique [0002] Sludge is the solid residue after sewage treatment, and the amount of sludge accounts for about 1‰ of the sewage treatment volume (calculated with a water content of 80%). With the continuous construction of sewage treatment plants, the amount of industrial and domestic sewage treatment in my country is increasing rapidly, and more sludge will be produced. The composition of sludge is very complex. In addition to a large amount of water, it also contains a large amount of organic matter, refractory organic matter, various trace elements, pathogenic microorganisms, parasite eggs, and heavy metals. How to make harmless and resourceful sludge with huge output and complex components has become one of the topics that the world's environmental circles have focused on. [0003] The sludge treatment metho...

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Problems solved by technology

However, if there is no heat user near the sludge incineration plant area, the hot water or steam generated by the water-cooled heating surface needs to be cooled by the cooling system, resulting in waste of heat

[0006] Chinese patent application CN1899988A discloses a wet sludge incineration treatment method with waste heat recovery, which uses the waste heat of the incinerator to dry part of the wet sludge, but does not disclose how to deal with the exhaust gas generated by the desiccator

Chinese patent application CN101210678A discloses a sludge drying and incineration integrated treatment method and device, which sends the low-temperature flue gas containing organic waste gas from the dryer to the upper part of the furnace dilute phase zone; in this method, the waste gas is in the furnace The residence time of the exhaust gas is short, and the harmful substances in the exhaust gas need to stay at high temperature for a sufficient time to completely decompose, so this method cannot guarantee the harmlessness of the exhaust gas

Chinese patent application CN101265008A discloses a sludge drying and incineration combined treatment method. The sludge is first dried by a fluidized bed dryer and then sent to an incinerator for incineration. The exhaust gas of the sludge dryer is sprayed to remove water and then passed into the furnace. Incineration; in this method, the water vapor in the sludge drying exhaust gas is condensed into waste liquid by the spray tower before being sent back to the furnace, so the water content in the furnace flue gas is less, and the flue gas enthalpy is lower; in addition, due to the invention A buried pipe is installed in the lower part of the furnace, and the fluidization velocity of the furnace is only 1.5-3m / s. It is not a circulating fluidized bed combustion in the true sense, but a bubbling bed. The temperature of the upper part of the furnace will be lower than that of the middle and lower parts of the furnace. It is only 600-700°C; at the same time, because the dry sludge discharge method of the sludge dryer is carried out of the dryer by the fluidization gas, and then separated by the cyclone separator, this means that the fluidization of the sludge dryer The speed must reach about 3m / s, which will make the fluidization air volume of the sludge dryer huge, and a large amount of low-temperature gas will be introduced into the dilute phase zone of the furnace, which will further reduce the temperature of the upper part of the furnace, which has already been reduced to 600-700 °C. It is difficult to ensure the high temperature removal of harmful substances in the sludge

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