JP5686433B2 - Waste melting treatment method - Google Patents

Description

  The present invention provides a waste melting treatment method using a waste melting apparatus in which a drying shaft portion and a pyrolysis residue melting portion are connected to each other through a grate portion to prevent unmelted matter from being mixed into the slag. It relates to technology for improving slag quality.

  In a shaft furnace type waste melting furnace that melts waste, there is a large amount of high-moisture waste such as garbage and volatile matter such as wood in the waste. When the volatile matter is lowered to the lower part of the furnace without being gasified, both moisture and volatile matter lower the ambient temperature. Therefore, in order to maintain the atmospheric temperature high and completely melt the non-combustible material, it is necessary to increase the amount of coke used as a result.

  Therefore, in waste melting treatment, drying and thermal decomposition are performed separately from combustion and melting to remove moisture and volatiles in the waste, and the waste is lowered to the bottom of the furnace without being dried or pyrolyzed. To suppress the consumption of coke used for melting ash by lowering the ambient temperature at the bottom of the furnace, thereby achieving complete melting with the heat of the pyrolysis residue and the heat of a small amount of coke. A waste melting treatment technique that can be used has been proposed (see Patent Document 1).

  As shown in FIG. 2, the waste melting furnace shown in Patent Document 1 thermally decomposes the waste dried by the drying shaft 1 and the drying shaft 1 to dry the charged waste. It comprises a melting furnace 6 having a grate part 2 for generating a pyrolysis residue and a pyrolysis residue melting part 3 for burning and melting the pyrolysis residue at the bottom. The drying shaft portion 1 is disposed above the entrance side of the grate portion 2, and the pyrolysis residue melting portion 3 is disposed below the exit side of the grate portion 2, communicated with the crank shape and integrally provided. ing. In addition, the thermal decomposition residue etc. which fell from the grate part 2 are discharged | emitted by the ash conveyance apparatus.

  The pyrolysis residue melting part 3 includes a lower hearth part 4 and a morning glory part 5 connected to the hearth part 4. The hearth part 4 is provided with a lower tuyere 7 for blowing air and oxygen as an oxygen source. An upper tuyere 8 for blowing air into the morning glory portion 5 may be arranged. A coke bed 18 is formed in the pyrolysis residue melting part 3 in the same manner as the bottom of a conventional shaft furnace type waste melting furnace. Auxiliary materials such as coke and limestone are fed from the auxiliary material inlet 15 at the top of the melting furnace 6.

  An exhaust gas outlet 9 and a waste charging inlet 10 are provided at the top of the drying shaft portion 1, and the waste charging inlet 10 is provided with a sealing lid 11 for preventing gas from blowing out during charging. . A waste transfer device 12 such as a pusher is provided below the drying shaft portion 1.

  The grate part 2 includes a grate 13 that moves the waste charged from the drying shaft part 1 to the pyrolysis residue melting part 3 while thermally decomposing the waste. Reference numeral 16 denotes an activation burner, and 17 denotes an air blowing port for blowing combustion air into the drying shaft portion.

  In the waste melting apparatus having the above-described configuration, the waste packed layer formed in the drying shaft portion 1 by being charged from the waste inlet 10 at the top of the drying shaft portion 1 is composed of the grate portion 2 and the thermal decomposition. The gas generated from the residue melting part 3 passes through and is efficiently heat-exchanged for drying. A pyrolysis residue 19 is generated by pyrolysis while moving the waste dried by the drying shaft unit 1 through the grate unit 2, and the generated pyrolysis residue falls into the pyrolysis residue melting unit 3 to form a coke bed. It is burned and melted by 18 heat sources, and the melt is discharged from the hot water outlet 14 of the hearth part 4. The exhaust gas passes through the waste of the drying shaft portion 1 and is exhausted from the exhaust gas outlet 9.

  The molten slag discharged from the hot water is rapidly cooled and solidified by a granulation facility to form a granulated granulated slag. The obtained granulated slag is used as a concrete aggregate.

JP 2010-255890 A

  In the melt treatment method described in the cited document 1, since coke and limestone, which are auxiliary materials, are directly fed into the pyrolysis residue melting portion, the coke and limestone that have been fed are not melted. If the granulated slag mixed in the slag is used as an aggregate in concrete, there is a risk that pop-out will occur where the concrete surface part partially peels off.

  Accordingly, the present invention provides a waste melting method using a waste melting apparatus in which a drying shaft portion and a pyrolysis residue melting portion are connected via a grate portion, in order to prevent concrete pop-out. It is an object of the present invention to provide a waste melting treatment method that prevents impurities from being mixed in.

In the invention of claim 1 of the present application, the waste is charged into the drying shaft portion from the top of the drying shaft portion for drying the waste to form a waste filling layer, and the formed waste filling layer is thermally decomposed. The gas generated in the grate part that generates the residue and the pyrolysis residue melting part that melts the pyrolysis residue using coke as a heat source is passed to dry the waste, and the gas that has passed through the waste packed bed is for drying Waste discharged from the top of the shaft part and dried at the drying shaft part is pyrolyzed at the grate part to produce a pyrolysis residue, and the generated pyrolysis residue is continuously dropped from the grate part and melted In the waste melting method of supplying and melting to the pyrolysis residue melting part of the furnace, discharging the molten slag and granulating the slag , stop the grate immediately before tapping or at least the last stage of the grate during tapping Stop the grate of the pyrolysis residue It stops the supply to the pyrolysis residue melting unit, a waste melting process how to characterized in that the stop limestone is secondary materials during tapping, the supply to the thermal decomposition residue fused portion of the coke.

Further, the invention of claim 2 of the present application is such that during the tapping, while the operation signal of the granulated water circulation pump is detected, the charging of the auxiliary material is automatically stopped, the tapping is finished, and the granulated water circulation pump The waste melting according to claim 1, wherein when the operation stops, the charging of the auxiliary material is resumed, and the auxiliary material skipped during the hot water is added together with the amount skipped in the next charging. It is a processing method.

  The present invention prevents contamination of the molten slag without supplying limestone unmelted material to the pyrolysis residue melting part immediately before tapping, and further prevents the mixture of pyrolysis residue or coke. It can be removed, improving the quality of concrete products containing slag. In addition, the improvement in slag quality allows the use to be expanded and resources to be used effectively.

It is the schematic of the waste melting furnace of this invention. It is the schematic of the conventional waste melting furnace.

  In the waste melting apparatus of the present invention shown in FIG. 1, the same components as those of the conventional waste melting furnace shown in FIG.

  In FIG. 1, the waste melting apparatus of the present invention is a drying shaft portion 1 for drying and pyrolyzing the charged waste, and further decomposing the waste dried and pyrolyzed by the drying shaft portion 1. And a pyrolysis residue melting part 3 of the melting furnace 6 for burning and melting the pyrolysis residue generated in the grate part 2. The drying shaft portion 1 is disposed above the entrance side of the grate portion 2, and the pyrolysis residue melting portion 3 is disposed below the exit side of the grate portion 2, communicated with the crank shape and integrally connected. Yes.

  A waste charging inlet 10 and an exhaust gas outlet 9 are provided at the top of the drying shaft portion 1. A waste filling layer is formed by the waste charged from the waste loading inlet 10 in the drying shaft portion 1. The gas generated in the grate part 2 and the pyrolysis residue melting part 3 passes through the waste packed bed to dry the waste by heat exchange, and the gas passing through the waste packed bed is discharged from the exhaust gas outlet 9 at the top. Is done.

  The grate part 2 includes a grate 13 that moves the waste dried by the drying shaft part 1 to the thermal decomposition residue melting part 3 while generating a thermal decomposition residue by thermal decomposition. The grate part 2 is formed by combining the movable grate 13a and the fixed grate 13b alternately in a staircase shape or an inclined shape, as in the case of the stoker furnace. The waste on the grate is advanced from the upstream side to the downstream side while being agitated by reciprocating at a constant pitch in the front-rear direction with a driving device such as a cylinder. Air is blown into the grate portion 2 from below. By providing the grate structure, the supply of the pyrolysis residue 19 to the pyrolysis residue melting section 3 is continuous and stable, and the pyrolysis residue melting section 3 ensures stable melting of the pyrolysis residue. Is possible.

  The grate unit 2 is divided into two stages, a front-stage grate group 2a and a rear-stage grate group 2b. The front-stage grate group 2a and the rear-stage grate group 2b have independent drive devices. By making the grate part into two stages of the front grate group 2a and the rear grate group 2b, the stirring of the waste in the grate part 2 can be strengthened, and drying and pyrolysis can be performed more efficiently. Can be done.

  Further, depending on the drying and pyrolysis status of the waste in the grate unit 2, the driving speed of the movable grate 13a by the independent driving devices of the front grate group 2a and the rear grate group 2b, the amount of air blown from the grate, Since it is possible to easily control the drying and thermal decomposition status of the waste in the grate section 2 by individually changing the blowing temperature and the like, it becomes possible to optimize the drying and thermal decomposition of the waste. . For example, when the dry / pyrolytic state of the waste is insufficient, the drying and pyrolysis state is improved by slowing the grate driving speed of the rear grate group 2b compared to the front grate group 2a. It becomes possible to do.

By doing in this way, a grate combustion load can be made into the range of 300-1000 kg / h / m < ² >, it becomes possible to reduce the amount of coke used, and to make the installation of a grate part small. The grate unit 2 may have three stages and four stages, but it is important to select an optimal number of stages in order to increase the aspect ratio.

  Further, it is desirable that the inclination angle of the rear-stage grate group 2b be smaller than the inclination angle of the front-stage grate group 2a. For example, as shown in FIG. 1, the rear grate group 2b is leveled to be smaller than the inclination angle of the front grate group 2a that is inclined downward toward the rear grate group 2b. ing. By changing the inclination angle, it is possible to enhance the stirring of the garbage. Furthermore, by making the inclination angle of the rear grate 2b gentler than that of the front grate 2a, a pyrolysis residue that is insufficiently dried and pyrolyzed is supplied to the pyrolysis residue melting unit 3 from the grate unit 2. It becomes easy to suppress this. By doing so, it becomes possible to optimize the amount of external combustion used such as coke in the pyrolysis residue melting part 3. In order to reliably supply waste from the drying shaft portion 1 to the grate portion 2, it is desirable that the front grate group 2a is installed in a horizontal step shape as shown in FIG. In addition, the thermal decomposition residue etc. which fell from the grate part 2 are discharged | emitted by the conveyor 20. FIG.

  The pyrolysis residue melting part 3 includes a lower tuyere 7 for blowing air and oxygen as an oxygen source in the hearth part 4, and an upper tuyere 8 for blowing air into the morning glory part 5. In the hearth 4, a coke bed 18 is formed as in the conventional shaft furnace type waste melting furnace, and a hot water outlet 14 for pouring the melt is provided. Auxiliary materials such as coke and limestone are input from the auxiliary material inlet 15 at the top of the melting furnace 6.

  In the waste treatment apparatus having the above-described configuration, the grate portion 2 is formed on the waste filling layer formed by introducing waste into the drying shaft portion 1 from the waste inlet 4 at the top of the drying shaft portion 1. And when the exhaust gas generated in the thermal decomposition residue melting part 3 passes, heat exchange is performed and the waste is efficiently dried. The heat-exchanged gas that has passed through the waste filling layer of the drying shaft portion 1 is exhausted from the exhaust gas outlet 9.

  The waste dried by the drying shaft portion 1 is pyrolyzed by the grate portion 2 to generate a pyrolysis residue 19. The generated pyrolysis residue 19 falls and accumulates in the pyrolysis residue melting part 3 from the residue outlet on the exit side of the grate part 2, and is burned and melted by the heat source of the coke bed 18. The melt is discharged from the outlet 14 of the hearth part 4.

  The molten slag discharged from the hot water is granulated and solidified by rapid cooling in a granulation facility, and recovered as a granulated slag.

  In the present invention, the grate is stopped immediately before the hot water to stop the supply of the thermal decomposition residue to the thermal decomposition residue melting part, and the charging of the coke and limestone to the thermal decomposition residue melting part is stopped during the hot water. By this operation, it is possible to prevent impurities from being mixed into the molten slag, so that the causative substance of pop-out can be removed.

<Conventional control method>
Regardless of the hot water, secondary materials (coke and limestone) are put into the furnace.
The charging is normally performed by dividing the charging amount (kg / h) set at a pitch of 1/10 minutes into 6 times.

<Control method when the present invention is applied>
During the hot water, the crushed water circulation pump (melt injection water injection pump) is operated, so that the charging of the auxiliary material is automatically stopped while the operation signal is detected.
When the hot water is discharged (usually about 5 to 10 minutes) and the water pulverized water circulation pump is stopped, the charging of the auxiliary material is resumed.
The auxiliary material skipped during the hot water supply is added together with the amount skipped in the next input.
As long as the auxiliary material is blown once, there is almost no influence on the coke bed layer and slag basicity (fluidity) at the bottom of the furnace.

  Molten slag pop-out is related to the amount of free lime (f-CaO). In the measured value by TBF method, if f-CaO exceeds 0.1%, there is a risk of pop-out occurrence. Table 1 shows an example in which f-CaO was measured by the tribromophenol method (TBF method), which is one of the methods for measuring f-CaO.

従来の制御方法ではｆ−ＣａＯが０．１％以上含まれることがあり、ポップアウトの危険性があるが、本発明では、０．１％未満であることが確認された。

In the conventional control method, f-CaO may be contained in an amount of 0.1% or more, and there is a risk of pop-out. However, in the present invention, it was confirmed that it is less than 0.1%.

1: Drying shaft part 2: Grate part 3: Pyrolysis residue melting part 4: Hearth part 5: Morning glory part 6: Melting furnace 7: Lower tuyere 8: Upper tuyere 9: Exhaust gas outlet 10: Waste equipment Entrance 11: Sealing lid 12: Waste transfer device 13: Grate 14: Outlet 15: Secondary material inlet 16: Burner 17: Drying shaft tuyere 18: Coke bed 19: Pyrolysis residue 20: Conveyor

Claims (2)

The waste is loaded into the drying shaft from the top of the drying shaft for drying the waste to form a waste filling layer,
Gas generated in the grate part that generates pyrolysis residue and the pyrolysis residue melting part that melts the pyrolysis residue using coke as a heat source is passed through the formed waste packed bed to dry and discard the waste. The gas that has passed through the packed bed is discharged from the top of the drying shaft,
Wastes dried on the drying shaft are pyrolyzed in the grate to produce pyrolysis residues,
In the waste melting treatment method in which the generated pyrolysis residue is continuously dropped from the grate portion, supplied to the pyrolysis residue melting portion of the melting furnace and melted, and the molten slag is discharged and granulated.
Stop the grate immediately before tapping or stop at least the last grate of the grate during tapping to stop the supply of pyrolysis residue to the pyrolysis residue melting part, and use auxiliary materials during tapping. A waste melting treatment method characterized by stopping charging of a certain limestone and coke into a pyrolysis residue melting portion . During the hot water, while the operation signal of the crushed water circulation pump is detected, the charging of the auxiliary material is automatically stopped.
When the hot water is finished and the crushed water circulation pump is stopped, the charging of the auxiliary materials is resumed.
2. The waste melting method according to claim 1, wherein the auxiliary material skipped during the hot water is added together with the amount skipped in the next charging .

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