JPH0630754B2 - How to put waste in the waste melting furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of use] The present invention relates to a method for charging waste in a waste melting treatment furnace. More specifically, the present invention relates to a method for charging waste in a waste melting treatment furnace for the purpose of averaging the electric power load on the electrodes.

[Prior Art] Waste such as incineration ash and dust generated when incinerating waste such as municipal waste in an incinerator includes, for example, human body such as chromium, nickel, manganese, cadmium, mercury, copper and the like. It is known that some of them contain heavy metals that are harmful to living organisms, and that their disposal is subject to national regulatory measures.

These wastes have been captured and removed by direct landfill disposal in the ground, adsorption of heavy metals on activated carbon, sedimentation as hydroxide by adding alkali, and binding to ion exchange resin. Later, the method of landfilling underground has been adopted. However, in both cases, not only is it becoming increasingly difficult to secure landfill sites, but when direct landfill disposal, heavy metals may elute into the ground and contaminate the surrounding area. The problem with the method of landfilling after disposal is how to treat the sludge containing the generated heavy metal-adsorbed activated carbon, heavy metal hydroxide, and heavy metal-bonded ion-exchange resin. There is a risk. In solving this problem,
For example, there is a proposal to perform melt processing using fuel, but the present applicant has proposed a method shown in Japanese Patent Laid-Open No. 52-143965 as a solution to the above problems. This method involves adding heavy metal-containing incineration residue or sludge resulting from the treatment of industrial waste, etc. to a base metal melted in an electric arc furnace, for example, a metal hot water made of iron, in a reducing atmosphere to add heavy metals to the base metal. In addition to being dissolved in it, it is also captured and fixed in the molten slag floating on the base metal.

As a furnace used for such a melting process, a submerged arc furnace having a shape of a rectangular parallelepiped in the longitudinal direction is known.
This furnace has a closed structure, and a plurality of artificial graphite electrodes for arc heat generation are inserted in a straight line in the longitudinal direction from the top through the furnace lid, and a melting initiator having an appropriate resistance value is placed in the furnace. Is charged and melted by Joule heat to form a so-called pool layer. The temperature of the water pool is 1450 to 1550 ° C
The high temperature molten state is maintained, and waste, for example, municipal waste incineration ash is charged and melted through a plurality of charging ports provided alternately with the electrodes. The basin layer and the base metal layer thereunder serve as Joule heat and arc heat generation source in the initial stage of operation of the furnace, and at the same time serve as a heat source for melting the incineration ash, and also as an iron or other heavy metal absorbing matrix in the incineration ash. It also has the function of. Most of the inorganic substances in the incinerated ash become molten slag and float on the base metal, and most of heavy metals such as iron, Cr, Ni, etc. migrate to the base metal, and some of them are fixed in the slag. And is discharged to the outside of the furnace through a plurality of outlets provided in the furnace body. In the melting process, some gas is generated in the furnace and discharged from the exhaust port. In the melting process furnace in the shape of a rectangular parallelepiped in the longitudinal direction, since the electrode lifting device can be arranged in a straight line on the back side of the furnace body, the design at the time of expansion is easy, and the addition due to the consumption of the electrodes, Easy maintenance such as replacement. In addition, the arrangement of equipment for carrying in wastes to be melt-processed is simplified. Since a plurality of incineration residue charging ports are installed per furnace, the charging load per charging port can be dispersed and reduced. Further, since the exhaust material inlet is disposed so that each position sandwiches the electrode, in other words, between the electrodes, the exhaust material is injected between the electrodes having the largest melting energy. The melt processing efficiency is good. Further, since the outlet is formed on one side surface, there is an advantage that the work of discharging the molten slag is easy.

Since the above-mentioned melting treatment furnace is equipped with multiple waste input ports, it is necessary to make the height of the waste accumulation layer almost flat just below each input port. By controlling, the input amount from each input port is adjusted. In addition, the number of level meters that detect the height of the deposited layer of waste is provided in the furnace according to the number of input ports, and the level of the deposited layer can be made uniform by controlling the input electric energy based on the detection signal of the level meter. Done.

[Problems to be Solved by the Invention] However, the adjustment of the amount of waste input based on the opening / closing control by the timer of the opening / closing damper of the inlet may not always make the height of the deposited layer of the waste uniform in the furnace. . In addition, the method based on input power control cannot be said to be an appropriate method because of imbalance in input power and consumption of power taps. In any of the methods, if the physical properties are uneven, such as waste (for example, municipal waste incineration ash), there is a local difference in the melting characteristics, and the deposition height of in-core waste during melting continues. Becomes uneven. In addition, in the latter method, in the case of an urban refuse incineration ash melting treatment furnace, since power generated by utilizing waste heat generated by waste incineration is used, 60 to 70% of the power generation load is consumed, and power generation The system load is large.

[Means for Solving the Problems] The present invention has been achieved as a result of various studies in order to solve the above problems, and has been achieved by a leveler meter for detecting the height of waste accumulation provided in a furnace. Based on the detected values of two or more levelers, the opening degree of the dumper of the waste dumper is controlled to provide a waste dumping method for achieving uniform waste pile height. . That is, the present invention has a plurality of waste input ports, detects the level of waste accumulated in the furnace by a plurality of level meters, and controls the waste input amount based on the detected values. When the difference between the maximum value and the minimum value among the detection values detected by each level meter exceeds the preset value in the waste injection method of the melting furnace, the waste is placed near the level meter showing the minimum value. The present invention has a gist of a method for charging a waste into a furnace for melting waste, which is characterized in that the height of a deposited layer of the waste in the furnace is averaged by charging.

Hereinafter, the present invention will be described with reference to the drawings. 1 to 3 show an example of a rectangular parallelepiped submerged arc heating and melting treatment furnace to which the present invention is applied. FIG. 1 is a schematic front view, and FIG. 2 is a schematic plan view. , Fig. 3 is X- in Fig. 2.
It is a fragmentary sectional view in the X'line. In the figure, reference numeral 1 denotes a furnace body made of a refractory material, and a lid 2 is provided on the upper portion thereof. In addition to the gas discharge port 3, the lid 4 is penetrated by electrodes 4A to 4F on the Y straight line, and sandwiched between these electrodes, a plurality of waste input ports 5A to 5E are arranged in parallel. . Furthermore, a plurality of level meters 6A to 6F for detecting the height of the deposited waste deposited are provided at a position sandwiched between the electrode and the waste inlet. During the charging chute of each waste charging port, waste a
Opening / closing dampers 7A to 7E for adjusting the input amount are opened and closed. Each of these dampers is a drive device 8A.
Rotated by ~ 8E. 9 is based on the detection signal from the level meters 6A to 6F, and is connected to the drive devices 8A to 8E and the damper 7
It is a control device that commands opening and closing of A to 7E. Reference numeral 10 is a molten slag outlet provided in the furnace body 1, 11 is a outlet cover, b is molten slag, and c is a base metal formed on the bottom of the furnace body. 12 is an electrode support arm, 13
Is an electrode lifting device, 14 is a maintenance inspection door, and 15 is a framework for reinforcing the furnace body.

In order to carry out the melting treatment of the waste by the method of the present invention using the submerged arc furnace of the above-mentioned type, as described above, first, a melting initiator or the like is charged into the furnace body 1 to melt, and 1450 to 1550. A hot water pool layer at a high temperature of ℃ is formed. Next, from the insertion ports 5A to 5E, the damper 7
A to 7E are opened, waste a is equally charged, and arc heating is performed. The molten slag b formed as the melting of the waste a progresses, is sequentially discharged from the outlet 10. At this time, the heights of the deposited layers of the waste a immediately below the respective inlets 5A to 5E are uneven and uneven among the respective inlets due to the unevenness of the physical properties of the waste and the difference in the density of the deposited layers.

According to the present invention, each level meter provided near the waste input port detects this non-uniformity, and therefore the difference between the maximum value and the minimum value among the scattered detection values is a preset value. If the value exceeds the limit, the damper at the waste input port closest to the level meter showing the minimum detection value is opened for a certain period of time by a timer to input the waste, and the height of the deposited layer is almost It tries to maintain a flat shape. The setting of the difference between the maximum and minimum detection values of the level meter in this case is empirically determined as the characteristic value of the furnace to be applied.

The above can also be performed by the following control mechanism.
That is, as indicated by the chain-dotted transmission path in FIG. 3, the level meters 6A to 6E detect the deposition height of the waste a in the furnace at regular intervals, and transmit the detection signal to the controller 9. . Then, in the control device 9, a program for calculating the difference between the maximum detection value and the minimum detection value from the detection values of the respective level meters and comparing it with the preset detection value, the detection value difference exceeds the set detection value. In this case, input both programs of the damper opening / closing drive device instructing the damper opening / closing drive to open the damper of one or two waste inlets near the level meter showing the minimum detection value for a certain period of time by a timer. It is a way to put. The detection operation of the level meter may be performed at regular time intervals.

[Operation] The maximum value and the minimum value among the detection values detected by a plurality of level meters are compared, and the waste is injected in the vicinity of the leveler meter showing the minimum value. Will be fixed. Therefore, a substantially horizontal waste accumulation level is ensured during the melting process.

[Example] A municipal solid waste incineration ash (water content: 10) was placed in a submerged arc heating and melting treatment furnace having a hearth area of 3.3 M ² as shown in FIG.
%) Was charged from the waste input ports 5A to 5E with the same damper opening time, and melted. That is, input port 5A
4 minutes cycle up to 5E, each damper 7A-7E is 3
The timer was set to 0 seconds. The detection of the height of waste accumulated by the level meters 6A to 6E was performed once every 5 minutes. The level meter was set so that the lower limit was 30 cm, the upper limit was 35 cm, and the upper limit was 45 cm.

When treating municipal solid waste incineration ash with normal physical properties, the deposition height of 30 to 35 cm (distance from the upper surface of the molten slag to the upper surface of the contact incineration ash of the level meter) was shown as the detected value for all level meters. However, Table 1 shows the lapse of time when the municipal waste incineration ash whose physical properties are largely deviated and the detected values of the level meters 6A to 6E are shown. In other words, the height of waste piled up in the furnace fluctuated, so when each level meter detected a detection value below the lower limit of 30 cm by the control device shown in Fig. 3, the damper near it was opened for 5 minutes. As a result, the height of the waste was adjusted and treated. For comparison, Table 1 also shows the case of processing without operating the control device.

From the above results, it was found that the following items (1) to (2) can be achieved according to the present invention with a control device.

Prompt response to changes in input speed due to changes in the contents of each input material (incineration ash).

Prompt response to the input speed for each selection according to the melting speed of incinerated ash.

Stabilization of voltage, power and conditions and reduction of molten slag heat dissipation by stabilizing the amount of incineration ash layer.

[Effect] As described above, the present invention corrects the variation in the level of the deposited waste introduced into the furnace in the melting process furnace of a rectangular parallelepiped shape in the longitudinal direction having a plurality of waste input ports and continues the melting. Since it keeps almost horizontal inside, it provides stable power and can greatly contribute to the field of waste treatment.

[Brief description of drawings]

The drawings show one example of a melting processing furnace to which the method of the present invention is applied. FIG. 1 is a schematic front view, FIG. 2 is a schematic plan view,
FIG. 3 is a partial sectional view taken along the line xx ′ in FIG. 1 ... Furnace body, 2 ... Furnace lid 3 ... Gas discharge port 4A, B, C, D, E, F ... Electrode 5A, B, C, D, E ... Waste input port 6A, B, C, D, E ... Level meter 7A, B, C, D, E ... Damper 8A, B, C, D, E ... Damper opening / closing drive device 9 ... Control device, 10 ... Outlet opening

Claims (3)

[Claims] 1. A waste melting system comprising a plurality of waste input ports, detecting the level of waste accumulated in a furnace by a plurality of level meters, and controlling the waste input amount based on the detected values. When the difference between the maximum value and the minimum value among the detection values detected by each level meter exceeds the preset value in the waste disposal method of the processing furnace, discard it in the vicinity of the level meter showing the minimum value. A method for charging waste into a waste melting treatment furnace, characterized in that the height of the deposited layer of the waste in the furnace is averaged by charging the waste. 2. The method of charging waste into a waste melting and processing furnace according to claim 1, wherein the waste is incineration ash of municipal waste. 3. The method for charging waste into the waste melting treatment furnace according to claim 1, wherein the waste melting treatment furnace is a submerged arc furnace.