JPS6053805B2 - Combustible sludge treatment method - Google Patents

Description

[Detailed description of the invention] The present invention relates to incineration treatment of combustible sludge.

More specifically, various types of sludge discharged from the treatment process of sewage, urine and various industrial wastewater are adjusted in advance to a moisture content and shape suitable for fluidized incineration using a rotary dryer 3, and then fed into a fluidized fluidized incinerator 6. The circulating fluidized bed created by blowing incineration air up from the bottom of the furnace is continued, thereby drying and burning the primary treated combustible sludge in the same process, and dispersing the resulting combustibles. The incinerated ash is continuously discharged from the incineration ash outlet to prevent heat radiation as much as possible during this time.
While maintaining the temperature in the incinerator, this combustion material is further transferred to the melting furnace 1.
The material is allowed to fall through 0 and melted instantaneously while being dispersed into individual granules, and then rapidly cooled to produce an artificial gravel-like material, preventing pollution such as the elution of harmful metals. It is something that I try to do. The technology of incinerating combustible sludge in a fluidized incinerator is a well-known technology, regardless of whether or not a fluidized medium is used. In this case, treatment was not sufficient due to the elution of heavy metals from the incinerated ash. Furthermore, as in JP-A-51-142876, a method has been proposed in which dehydrated muddy waste is compressed and granulated and the granular waste is combusted.

However, in such a method, the granulation process and the incineration process are separate processes, and the muddy waste cannot be continuously processed. This has the disadvantage of requiring a huge amount of equipment.
Furthermore, as in Japanese Patent Application Laid-Open No. 52-148475, a method has been proposed in which incinerated ash once discharged from an incinerator is stored in a storage tank and subjected to high-frequency heating to form clinker.

However, in this method, since the incinerated ash is once discharged from the incinerator, it loses the amount of heat in the incinerator. Therefore, in the storage tank, it must be reheated to the melting point using high frequency, and a large amount of heat is required for high frequency heating. Furthermore, since the incinerated ash overflows from the storage tank, not only the particle size becomes non-uniform, but also the problem is that fine particle size cannot be obtained. The present invention aims to solve the problems of the prior art. That is, the present invention has the advantage of being able to produce pollution-free artificial gravel continuously and reliably with a small amount of high-frequency heating heat due to the above-described configuration. Examples of the present invention will be described below. Hot air of approximately 800° C. is sent from the hot air generating furnace 1 to the rotary dryer 3.

Approximately 80% moisture supplied from feeder 2 to rotary dryer 3
The urine and urine sludge is collected using hot air from hot air generator 1 and rotary dryer 3.
The rotary dryer 3 reduces the average particle size to 2 to 6wn.
The pellets are granulated to a diameter of φ, dried to a moisture content of approximately 20%, and sent to a fluidized incinerator 6 via an exhaust pipe 7. After the dust contained in the dry exhaust gas is collected by the cyclone separator 4, it is mixed with the dry matter and is fed into the fluidized incinerator 6 through the exhaust pipe 7. Since the fluidized incinerator 6 processes the material without using a fluidized medium, the incinerated ash particles remain in a dispersed state as described below and can be removed from the overflow. It is taken out to the low vibe 12. The exhaust gas at about 700°C containing a small amount of ash after incineration enters the heat exchanger 8, and the air from which dust has been removed from the dryer 3 via the cyclone 4 is heated from about 200°C to 500°C.
It is used as secondary air in the hot air generating furnace 1 and the hot air generating furnace 5 for fluidized incineration in the fluidized incinerator 6. The incinerator exhaust gas containing a small amount of incinerated ash whose temperature has been lowered from about 700° C. to about 300° C. by heat exchange in the heat exchanger 8 is separated and purified by the cyclone 9, and then released into the atmosphere. Most of the incinerated ash of the waste that has been dried and incinerated in the fluidized fluidized incinerator 6 is taken out from the fluidized fluidized incinerator by an overflow vibe 12, and the melting furnace 10 is installed vertically around the vertical part of the overflow vibe 12 and used. The ash is continuously melted instantaneously in a dispersed state, and the molten ash is filled with water and dropped into a quenching tank 11.
To manufacture non-polluting artificial gravel with uniform density and appearance. That is, the incineration ash is prepared in advance with an average particle size of 2 to 6 mm.
The incineration ash is granulated into overflow vibrator 12.
At the time it entered the country, it was not formed into artificial gravel, but had a rough structure similar to volcanic ash. This incinerated ash is instantaneously melted in a melting furnace 10 at a high temperature of 1200° C. or higher, and then rapidly cooled, thereby tightening the rough structure and making it resemble artificial gravel. Harmful ingredients are trapped in these artificial gravel-like particles. In addition, in the incineration ash, the above-mentioned 2 to 67077! Fine particles smaller than φ also exist.

These fine particles are then melted in the high-temperature heating zone of 1200°C in the melting furnace 10, but since the falling speed of the fine particles is low, they fall at a higher speed of 2 to 67 mφ.
It sticks to the particles in a molten state and falls together with the larger particles. In this way, non-polluting artificial gravel-like particles are formed. In addition, in order to make the incinerated ash fall in a dispersed state in the overflow vibe 12, an eaves 12c is provided at the extension of the inclined part 12a at the boundary between the inclined part 12a and the vertical part 12b of the overflow vibe, as shown in the drawing. The incinerated ash that has slid down the portion 12a falls down the vertical portion 12b in a dispersed state. Since the incinerated ash falls in a dispersed state in this manner, it is efficiently melted in the melting furnace 10.

The ash recovered by the cyclone 9 is fine powder and has a low temperature, so it is returned to the feeder 2. Note that instead of the melting furnace using an oxyhydrogen flame, a melting furnace, an arc melting furnace, or a plasma melting furnace using a mixed gas flame capable of generating a high temperature of 1200° C. or higher may be used. Further, it is preferable to add a fluxing agent such as slaked lime to the raw material sludge in the feeder 2 in order to promote melting in the melting furnace.

The effects of the present invention are summarized as follows.

5 The incinerated ash particles from the fluidized incinerator 6 have an average particle size of 2 to 6 in advance.
Since the particles are granulated to a Tnφ and moisture content of 10 to 50% and then incinerated, when they are discharged into the overflow vibe 12, they are particles with a coarse structure similar to volcanic ash.

Then, particles with a coarse structure like this volcanic ash are melted into the melting furnace 1.
By melting at a high temperature of 0, it becomes dense artificial gravel-like particles, so harmful components are trapped in these artificial gravel-like particles, and no pollution is generated. Fine particles are also present in the incineration ash, but the falling speed of the fine particles is low and they are in a floating groove state. φ
particles with a larger diameter.

Therefore, the harmful components of the small particles are similarly trapped in the artificial gravel-like particles and do not cause pollution.

The average particle size is 2 to 6 Tnmφ and the moisture content is 1 using the 5-rotation dryer 3.
Since this is granulated to 0 to 50% and inserted into the fluidized incinerator 6, which does not use a fluidized medium, the incinerated ash remains granular in the melting furnace 10, and artificial gravel-like particles are dispersed. It can be continuously supplied to the melting furnace 10 in that state.

If a fluid medium is used, the medium must be divided;
At that time, the amount of heat in the incinerator is released, so the high temperature of the incinerated ash of 400 to 800° C. cannot be maintained as in the present invention.
6 Conventionally, there has been a technical idea to solidify incineration ash into droplets in this way, but if it is made into droplets in a fluidized fluidized furnace,
Due to its stickiness, it sticks to the floor or wall of the fluidized bed incinerator, making it impossible to operate the fluidized bed incinerator.

There have also been many attempts to obtain granules by rolling the melt in a rotary kiln, but the conditions for rolling and granulating the melt are extremely narrow, making practical operation impossible.
However, in the method of the present invention, the ash, which has been granulated in advance and heated to a temperature on the verge of melting, is passed through a hot gas in a dispersed state and melted during this period, so the operation is extremely stable and there is no risk of troubles such as fusion to the equipment. few.

[Brief explanation of the drawing]

The drawing shows a flow sheet of the method of the invention. 1...Hot air generator, 2...Supplier, 3
...Rotary dryer, 4...Cyclone,
5...Hot air generator for fluidized incinerator, 6...
・Fluidized incinerator, 7...feeder, 8...
Heat exchanger, 9...Cyclone, 10...Plasma melting furnace, 11...Quieting tank, 12...
...Overflow vibe.

Claims (1)

[Scope of Claims] 1. Various sludges with a moisture content of 70 to 95% discharged from the treatment process of sewage, excrement, and various industrial wastewater are granulated into granules with an average particle diameter of 2 to 6 mmφ by a rotary dryer 3, and It is dried to a moisture content of 10 to 50%, then incinerated while maintaining its granularity in a fluidized incinerator 6 that does not use a fluidized medium, and then continuously passed through an overflow pipe 12 connected to the upper part of the fluidized incinerator 6 in a dispersed state. A hollow cylindrical heating zone capable of generating a high temperature of 1200°C or more is used to process the incinerated ash having a temperature of 400° to 800°C, and the melting furnace 10 is arranged vertically around the vertical part 12b of the overflow pipe 12. The incinerated ash particles are continuously dropped and passed around the center, and are melted in a dispersed state.Then, the incinerated ash particles are discharged from the melting furnace 10, where they are melted in the granular state and the particles are still in the dispersed state. A method for treating combustible sludge, which is characterized by rapidly cooling molten ash with water to produce non-polluting artificial gravel-like material exhibiting uniform density and appearance. 2. The method according to claim 1, which comprises using a plasma melting furnace as the melting furnace. 3. The method according to claim 1, wherein an arc melting furnace is used as the melting furnace. 4. The method according to claim 1, which uses a melting furnace that uses a mixed gas flame that can generate a high temperature of 1200° C. or higher. 5. The method according to claim 1, wherein a fluxing agent such as slaked lime is added to the sludge in advance in the feeder.