JP2997989B2 - Method for treating incineration residue discharged from marine incinerator using slurry filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an incineration residue discharged from a marine incinerator for treating shells, edible shell meat or shells after collecting pearls, etc. attached to cooling sea waterways of various factories and power plants. Regarding the processing method.

[0002]

2. Description of the Related Art Seawater is often used as cooling water in power plants, steelmaking plants, chemical plants, and the like. When seawater is used as cooling water, seawater such as shellfish adheres to and grows in the waterway (pipeline), and as a result, the required amount of water cannot be secured. Therefore, it is necessary to periodically remove these seawater.

[0003] Marine organisms including these shells are usually incinerated in an incinerator such as a rotary kiln. By performing this incineration method, calcium carbonate (CaCO ₃ ) as a main component is converted into quick lime (CaO) by a reaction represented by the following formula (1). By adding more water,
Slaked lime [Ca (O
H) ₂ ].

[0004]

## EQU1 ## CaCO ₃ = CaO + CO ₂ -42.9 kcal / mol (1)

[0005]

## EQU2 ## CaO + H ₂ O = Ca (OH) ₂ +15.2 kcal / mol (2)

[0006] In order to convert quicklime, which is an incineration residue generated by the reaction of the formula (1), into slaked lime suitable for processing such as transportation and landfill, it is necessary to convert the quicklime into slaked lime by performing a digestion reaction of the formula (2). . As this method, a dry method and a wet method are known.

[0007] In the dry method, quicklime, which is an incineration residue, is transported from an incinerator by a screw conveyor, a flight conveyor, or the like, and then water required for digestion, cooling, and humidification is sprinkled in a digestion tank such as a special Nauta mixer. Perform digestion, cooling and humidification. At this time, the fine powder of slaked lime generated by the digestion reaction and the water vapor generated by the heat generated by the digestion reaction are sucked by a blower and removed by a bag filter or the like.

On the other hand, the wet method is disclosed in, for example,
As disclosed in Japanese Patent Application Publication No. 8 (1999), a method is used in which the incineration residue is immersed in a water tank and scraped up with a scraper. JP-A-6-72745 discloses that the immersion time of incineration residues immersed in a water tank is controlled so that H ₂
It is disclosed that as a result of making the O / CaO reaction equivalent ratio less than 0.7, the amount of residual water adhering to the incineration residue after immersion is reduced.

[0009]

In the case of the dry method,
Because the water to be added is bumped by the exothermic reaction with quicklime,
The fine powder of slaked lime produced is rolled up and accompanied by water vapor, adheres to the exhaust duct and the bag filter for dust collection and closes it, thereby hindering stable operation and automatic operation.

In the above-mentioned wet method, fine powder of slaked lime generated in the water tank to be immersed in the water tank is concentrated as a slurry, so that the slurry accompanies the scoured slaked lime and the water content increases. As a result, spilling of the separated slurry during transportation and adhesion and fixation of sludge to the transport equipment occur.

Also, there is a problem in that the environment is hindered, such as clogging due to sludge adhesion in the hopper, and furthermore, when transporting incineration residue discharged from the hopper, slurry is spilled on public roads.

In the technique disclosed in Japanese Patent Laid-Open No. Hei 6-72745, the digestion reaction in a water-sealed tank is set to an H ₂ O / CaO reaction equivalent ratio of less than 0.7, so that the residual moisture adhering to the incineration residue is reduced to 30% or less. It is shown that This method
It is possible to achieve the purpose by adjusting the conveyor speed and the water transfer distance in the water seal tank,
There is a problem that the control is difficult.

The present invention has been made in view of the above problems, and provides a method for treating incineration residues that easily and stably produces marine incineration residues having water suitable for handling with simple equipment.

[0014]

According to the present invention, there is provided an incineration residue using a marine incineration apparatus having a water ring tank provided with an incineration residue discharge conveyor below an incineration residue discharge port of an incinerator. In the treatment method, the fine slurry-like slaked lime powder generated in the water seal tank by the digestion reaction is withdrawn from the middle stage of the water seal tank, and separated into water and solids by a centrifuge or a filtration separator, On the other hand, a method for treating incineration residues discharged from a marine incinerator using a slurry filter, wherein the coarse residue remaining in the water seal tank is conveyed by a conveyor with a scraper and mixed with the separated solid matter. It is.

[0015]

According to the present invention, fine slurry-like slaked lime powder produced by the digestion reaction in the water-sealed tank is extracted from the middle stage of the water-sealed tank and removed by a centrifugal separator or a filtration separator to reduce water content. The slaked lime powder is returned to the hopper, and the separated water is returned to the water seal tank.

On the other hand, the incineration residue of coarse particles scooped up from the bottom of the water-sealed tank is often drained and does not accompany the slurry, so that it is conveyed to the above-mentioned hopper in a state where the attached moisture is reduced, and the separated solid matter is separated. Mixed with. The moisture content of the obtained mixed incineration residue is 20 to 30%, and the handling of the residue is easy.

[0017] Sea life including shells is incinerated by a rotary kiln or the like at an exhaust gas temperature of about 700 to 850 ° C.
The incineration residue enters a water seal tank with a scraper provided in the lower part of the incinerator. In the water seal tank, a slurry containing fine slaked lime powder generated by the digestion reaction is generated. This amount of slurry increases with an increase in the amount of incineration residue treated, and the slurry concentration also increases, eventually leading to malfunction of the water seal tank. For this reason, this slurry is extracted from the middle stage of the water-sealed tank and solid-liquid separated by a centrifugal separator or a filtration type separator. The solid with reduced moisture is stored in a hopper, and the separated water is returned to a water seal tank.

On the other hand, in the water-sealed tank, coarse incineration residues remain as a result of removal of the slurry. Since the residue is coarse, the drainage is good and the amount of water adhering to the residue scraped up by the scraper is reduced. When the residue is transported, the slurry does not spill or adhere to the transport device, and is transported to the hopper to be mixed and stored with the above-mentioned centrifugal separator separated solid. Through such a process, the amount of water adhering to the incineration residue mixed and stored in the hopper is 20 to 30%, and a residue that can be easily handled is obtained.

As a preliminary test, the inventors of the present application have investigated the adhering water of the mixed incineration residue stored in the hopper.
It turned out to be 20-30%. This water content is 2
When the content is 0% or less, the dusting property increases, and when the content is 30% or more, the fluidity increases.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiment shown in FIG.

FIG. 1 shows an example of an apparatus for incinerating and digesting marine organisms. A shell containing mud adhering to a cooling seawater channel or the like of a power plant is rotated from a charging hopper 1 to a rotary kiln 4 by a charging screw conveyor 2. And in the rotary kiln 4, about 700 to 850 ° C. due to the combustion exhaust gas of the burner 3.
The incineration residue was dropped from the incineration residue outlet duct 8 at the bottom of the furnace hood 6 into the water-sealed tank 7.

Next, slaked lime slurry generated by the digestion reaction of the water sealing tank 7 is selectively extracted from the middle stage of the water sealing tank 7 by the slurry transfer pump 12 and charged into the centrifugal separator 13. 11 and the separated water was sent back to the water seal tank 7. In this embodiment, this separation is described using a centrifuge, but a filtration type separator may be used.

The coarse-grained residue remaining in the water sealing tank 7 was scraped out by a conveyor 14 with a scraper, and was conveyed to a hopper 11 by an incineration ash transfer conveyor 10. It was confirmed that there was no spilling of the slurry during the transportation and that the adhesion to the transportation equipment was small. Further, the mixed incineration residue stored in the hopper 11 was confirmed to have good handleability, and it was also found that the amount of adhering moisture was 20 to 30%.

[0024]

As described above, the method for digesting incineration residues of marine organisms according to the present invention has a problem in transporting separated slurries, which is a conventional wet method, in treating marine organisms having unstable properties such as shells. Solve the problems such as difficulty in controlling the conveyor conveyance speed, etc., remove the slaked lime powder generated in the water seal tank by the digestion reaction from the water seal tank, separate it into moisture and solids, and By mixing
The water adhering to the residue can be maintained at 20 to 30% suitable for handling, so the digestion treatment apparatus is also very simple compared to the conventional one, and the incineration residue having a water content suitable for handling and transport can be easily and stably obtained. Can be produced.

[Brief description of the drawings]

FIG. 1 is a schematic side view showing an example of a marine incineration and digestion treatment apparatus suitable for performing the residue digestion treatment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sea life loading hopper 2 Sea life loading screw conveyor 3 Burner 4 Rotary kiln 5 Incineration gas 6 Furnace bottom hood 7 Water seal tank 8 Incineration residue outlet duct 9 Incineration residue 10 Incineration ash transfer conveyor 11 Incineration ash hopper 12 Slurry transfer pump 13 Centrifuge 14 Conveyor with scraper

Continuing from the front page (72) Inventor Tetsuo Ishikawa 46-59, Ohara Nakahara, Tobata-ku, Kitakyushu Nippon Steel Plant Design Co., Ltd. (72) Inventor Shigeru Mitarai 46-59, Ohara Nakahara, Tobata-ku, Kitakyushu Nippon Steel Plant Design Stock In-company (58) Field surveyed (Int.Cl. ⁷ , DB name) C04B 2/04 C04B 2/08 F23G 5/00 F23J 1/00

Claims (1)

(57) [Claims] 1. A method for treating incineration residues using a marine incineration treatment apparatus having a water ring tank provided with an incineration residue discharge conveyor below the incineration residue discharge port of an incinerator, wherein the digestion reaction causes the incineration residue to enter the water ring tank. The resulting fine slaked lime powder is extracted from the middle stage of the water-sealed tank and separated into water and solids by a centrifuge or a filtration separator, while the coarse-grained residue remaining in the water-sealed tank is transported by a conveyor with a scraper. And treating the incineration residue discharged from a marine incinerator using a slurry filter.