JPH06257731A - Sludge incinerating method - Google Patents

Abstract

PURPOSE:To enable incineration processing of sewage sludge by a fluidized bed kiln without necessitating any large space or any heat source by mixing high-temperature collected dust separated from an outlet gas of the fluidized bed kiln with sludge and throwing sludge into the fluidized bed kiln after being formed into lump or powder. CONSTITUTION:Circulating flow is generated in a kiln by high-speed flowing air to be blown out from a flowing air blow-out port 2 on the lower part of a circulating fluidized bed kiln 1. The high-temperature outlet gas to be take out from the upper part of the circulating fluidized bed kiln 1 is separated into gas solid to be guided to a cyclone separator 3. And, exhaust gas is sent to an exhaust processor. The collected dust recovered from the cyclone separator 3, and having high temperature of about 800 deg. is sent to a mixer 4, and it is mixed with sewage sludge having a moisture of about 80% therein. The sewage sludge is dried and formed into lump or powder by being mixed with this high-temperature collected dust. The mixture discharged from the mixer 4 is dried by a dryer 5 and thrown into the circulating fluidized bed kiln 1.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for incinerating sludge such as sewage sludge using a fluidized furnace.

[0002]

2. Description of the Related Art Incineration in a fluidized furnace is widely known as a method for treating sludge such as sewage sludge. By the way, in the fluidized furnace for incinerating sewage sludge, after the sewage sludge is dried to a predetermined moisture by a type that directly inputs the sewage sludge into the furnace and a screw type indirect heating dryer that uses a heat source such as steam, There is a type to put in the furnace. However, the direct charging type has a problem that the processing capacity is low because it needs to be dried in the furnace. On the other hand, when the indirect heating dryer and the fluidized furnace are combined, there is a problem that a large space and a heat source for the indirect heating dryer are required.

In addition to the ordinary fluidized-bed furnace, a higher-performance circulating fluidized-bed furnace has been developed, in which the gas velocity is increased to allow external circulation of particles. However, in this circulating fluidized furnace, the sewage sludge cannot be floated by the gas flow unless the sewage sludge is previously dried by an indirect heating type dryer and then added. Therefore, an indirect heating dryer is inevitably required when a high-performance circulating fluidized furnace is used.

[0004]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned conventional problems and provides a sludge incineration method capable of incinerating sewage sludge by a fluidized furnace without requiring a large space or a heat source. It was done for good.

[0005]

The present invention, which has been made to solve the above-mentioned problems, is to mix high temperature dust collecting ash separated from the outlet gas of a fluidized furnace with sludge to form sludge into a lump or a powder. In addition, it is characterized in that it is charged into a fluidized furnace.

[0006]

EXAMPLES The present invention will be described in more detail below with reference to the flow chart of the examples of sewage sludge shown in the drawings. In the first flow shown in FIG. 1, reference numeral 1 is a circulating fluidized furnace, and high-speed fluidizing air blown from a fluidizing air blowing port 2 in the lower portion thereof causes a circulating flow in the furnace. The hot outlet gas taken out from the upper portion of the circulating fluidized furnace 1 is guided to the cyclone 3 and separated into gas (exhaust gas) and solid (dust collecting ash). Then, the exhaust gas is sent to the exhaust gas treatment device. The above process is similar to the conventional process.

On the other hand, about 800 recovered from cyclone 3
The high temperature dust collecting ash of ℃ is sent to the mixer 4, where the water content is about
Mixed with 80% sewage sludge. The sewage sludge is dried into a lump or a powder by being mixed with the high temperature collected ash. Therefore, when the sewage sludge mixed with the dust collecting ash is put into the circulating fluidized furnace 1, it can be blown up by the high-speed fluidizing air without increasing the pressure loss of the fluidized bed and efficiently combusted.

The mixing ratio of the collected ash is 100 to 200% by weight with respect to sludge such as sewage sludge. This mixing ratio is 10
If it is less than 0%, the sludge is insufficiently dried, and the circulation and combustibility when charged into the circulating fluidized furnace 1 are deteriorated. On the other hand, if the mixing ratio exceeds 200%, the amount of sludge input will decrease relatively, and the treatment efficiency will decrease. If the two are mixed at an appropriate ratio in this way, it is possible to dry the sewage sludge by utilizing the retained heat of the dust ash that was conventionally wasted. Although the circulating fluidized furnace has been described in the present embodiment, it goes without saying that the ordinary fluidized furnace has a considerable effect.

In the second flow shown in FIG. 2, the mixture discharged from the mixer 4 is further dried by the dryer 5, and
It is put into the circulating fluidized furnace 1. This dryer 5 blows air at room temperature with a blower to remove water vapor.
The sewage sludge is lumped or powdered by being mixed with high-temperature dust collecting ash in the mixer 4, so that it can be easily dried by air at room temperature.

[0010]

As described above, according to the method for incinerating sewage sludge of the present invention, the sewage sludge can be dried by utilizing the sensible heat of the dust ash that was conventionally discarded in vain. Sludge can be incinerated with good combustibility in a high-performance fluidized furnace. Further, unlike the conventional indirect heating type dryer, the mixer can be small in size, so that the space can be reduced and an extra heat source is unnecessary. Therefore, the present invention greatly contributes to industrial development as a method for incinerating sludge such as sewage sludge that solves the conventional problems.

[Brief description of drawings]

FIG. 1 is a flow sheet illustrating a first flow of the present invention.

FIG. 2 is a flow sheet illustrating a second flow of the present invention.

[Explanation of symbols]

 1 Circulating flow furnace 3 Cyclone 4 Mixer 5 Dryer

Claims (2)

[Claims] 1. A method for incinerating sludge, which comprises mixing hot dust ash separated from the outlet gas of a fluidized furnace with sludge, making the sludge into a lump or a powder, and charging the sludge into the fluidized furnace. 2. The method for incinerating sludge according to claim 1, wherein the sludge in the form of lumps or powder is further dried with air at room temperature and then put into a fluidized-bed furnace.