JPH07294144A - Smoke dust melting and solidifying apparatus - Google Patents

Abstract

PURPOSE:To provide a smoke dust melting and solidifying apparatus which efficiently and safely can melt and solidify smoke dust even when the apparatus is used for any of a fuel fired melting furnace and an electric melting furnace. CONSTITUTION:A smoke dust supply unit 3 is provided continuously to the smoke dust introducing port 4 of an electric arc furnace 1, and the slag discharge port 7 of the furnace 1 is watertightly sealed by a cooling water tank 10. The unit 3 has a partition wall 14 having a plurality of small-diameter holes for partitioning to a smoke dust supply case 13, an introducing chamber 13b which allows the case 13 to communicate with the port 4, and a pressure feeding chamber 13a connected to a hopper 17, and a screw conveyor 15 arranged in the chamber 13a to pressure feed smoke dust 9a supplied from the hopper 17 to push it from the holes of the wall 14 to the introducing chamber.

Description

Detailed Description of the Invention

[0001]

[Industrial field of application] Traditionally, the soot dust collected by dust collectors from the combustion gas generated in an incinerator when incinerating municipal solid waste, etc. was used as landfill, but at present, "Waste Disposal and Cleaning Law"
As a result of the amendment, it is said that final disposal such as landfill cannot be performed for soot and dust containing a large amount of harmful heavy metals and dioxins unless the intermediate treatment specified by the Minister of Health and Welfare is performed. That is, it is melt solidification, cement solidification, chemical treatment, treatment with a solvent such as an acid. The present invention is an apparatus for performing a melting and solidifying treatment among such intermediate treatments, and in particular, a melting furnace provided with a soot dust inlet and a slag discharge port, and a soot dust supplying device connected to the soot dust inlet. And a slag cooling and solidifying apparatus having a cooling water tank for sealing the slag discharge port with water, and a soot dust melting and solidifying apparatus.

[0002]

BACKGROUND OF THE INVENTION In the above-mentioned melting and solidifying treatment, soot dust is melted at 1300 to 1400 ° C. in a melting furnace and taken out as vitrified slag, which is cooled (slow cooling or rapid cooling) to slag heavy metals. It can be contained in the organized organization. The molten slag is detoxified in landfill or is effectively used (for example, it is used as a raw material for cement aggregate, tile, etc.). On the other hand, Cd, Pb, H contained in soot and dust
The low melting point substance such as g is volatilized in the melting furnace, discharged with the exhaust gas, cooled, and collected by a bag filter or the like. In addition, the collected volatilized matter is the above-mentioned cement solidification,
It is necessary to perform immobilization and stabilization treatment (hereinafter referred to as “post-treatment”) by either a chemical treatment or an acid extraction method, but the amount thereof is extremely small.

Such melting and solidifying treatment is generally carried out by a surface burning furnace, an internal melting furnace, a coke bed melting furnace, a swirl flow melting furnace, a fuel burning melting furnace, an electric arc furnace, an electric resistance furnace, a plasma melting furnace, and an electric heating. Electric melting furnaces such as furnaces and microwave melting furnaces are used.

However, most of the dust collected by the electric dust collector, bag filter, etc. is a fine powder having a particle size of 1 μm or less, and therefore it is introduced into the melting furnace by a dust feeder such as a screw feeder. If so, most of them are likely to scatter and float in the air, and a large amount of soot dust may be discharged outside the furnace together with the exhaust gas without being melted. For this reason, the melt processing efficiency becomes extremely poor, and the post-processing amount increases.

In particular, in a fuel-fired melting furnace such as a surface melting furnace for melting and processing gas, kerosene, coke, etc.,
Since the amount of combustion gas such as kerosene is large, if fine dust soot is added as it is, the soot dust is blown up by the burner flame and the amount of soot dust entrained in the exhaust gas increases, and the above-mentioned unmelted soot dust generation rate is extremely high. Become. In a swirling flow melting furnace called a cyclone furnace even in a fuel-fired melting furnace, the above-mentioned problems do not occur because originally the powdery and granular material to be melted is blown into the furnace. The larger the particle size, the more closely it adheres to the furnace wall due to centrifugal force and melts. Therefore, in reality, the melting processing efficiency is not so good for soot dust with a very small particle size.

Further, as a soot dust supplying device to the melting furnace,
A screw feeder or the like is generally used except for the swirling flow melting furnace described above, and air is prevented from entering from the soot dust introduction port of the melting furnace by a material seal of soot dust filled in the feeder. Therefore, in combination with the slag discharge port of the melting furnace being water-sealed by the cooling water tank, the inside of the furnace is kept airtight.

However, when the amount of soot dust supplied to the soot dust supply device is insufficient, the above-mentioned material sealing effect is not exerted, and air enters the furnace through the soot dust inlet. When such an air intrusion occurs and the airtightness in the furnace is not maintained, when using an electric melting furnace such as an electric arc furnace using a carbon electrode, an electric resistance furnace, or a plasma melting furnace, Since a large amount of CO is generated as the electrodes are consumed, an explosion accident may occur. Therefore, when using such an electric melting furnace, it is necessary to take explosion-proof measures such as enclosing N ₂ gas.

[0008]

SUMMARY OF THE INVENTION In view of the above-mentioned problems, the present invention does not cause the problems as described above and melts soot and dust in any of the fuel-burning melting furnace and the electric melting furnace. It is an object of the present invention to provide a soot dust melting and solidifying apparatus which can favorably perform solidifying processing.

[0009]

In the soot dust melting and solidifying apparatus of the present invention, in order to achieve the above object, in particular,
Multiple small-diameter holes that divide the soot / dust supply device into a soot / dust supply case connected to the soot / dust input port, a soot / dust input chamber communicating with the soot / dust input port, and a soot / dust feeding chamber to which the soot / dust supply hopper is connected. And a pusher that is disposed in the dust pushing chamber and pushes the dust supplied from the hopper and pushes it out through the small-diameter hole of the bulkhead to the dust input chamber. I suggest you keep it. In such a dust supply device, it is preferable to dispose a cutting body for cutting the compression rod-shaped material of the dust extruded from the small-diameter hole of the partition body into a predetermined size in the dust introduction chamber.

[0010]

[Function] The fine dust particles supplied from the dust supply hopper to the dust pushing chamber are pushed toward the partition body by the pushing body,
The small-diameter hole of the partition body pushes it out into the soot-filling chamber. That is, the dust is compressed into a rod shape and then pushed out into the dust input chamber. Since this rod-shaped compression molded product is a brittle material, when it is extruded from the partition wall by a predetermined amount, it is broken by its own weight and falls to the dust input port. Further, when a cutting body is provided in the soot dust input chamber, the rod-shaped compression molded product is actively broken and cut by the action of the cutting body, and falls into the dust dust introduction port. In any case, in the melting furnace,
Soot and dust are dropped and supplied in the form of compression molded pellets.

Therefore, unlike the case of supplying fine dust soot to the melting furnace as it is, the dust does not scatter in the furnace, and the soot remains unmelted regardless of the amount of exhaust gas discharged from the furnace. All the soot dust put into the furnace will be melted without being discharged outside the furnace together with the exhaust gas. Therefore, the post-treatment such as cement solidification is performed only on the volatile matter discharged together with the exhaust gas, and the amount thereof is extremely small. Even when using a swirl-flow melting furnace, as described above, if the soot dust is compressed and then supplied, the particle size of the melted material becomes large, and it adheres to the furnace wall by centrifugal force. Since it melts, the melting efficiency is remarkably improved as compared with the case where fine powdery dust is supplied as it is.

Further, since the small diameter hole of the partition wall is always filled with soot and dust, the soot and dust supply amount from this hopper is insufficient even in an extreme case where the soot and dust supply hopper becomes empty. Even if the material sealing effect due to the dust in the dust pushing chamber is not exerted, the dust pushing chamber and the dust feeding chamber are completely cut off. That is, air does not enter from the dust input port connected to the dust input chamber regardless of the variation of the amount of dust input to the dust input device. Therefore, in combination with the fact that the slag discharge port is water-sealed by the cooling water tank, the inside of the melting furnace is always kept in an airtight state with no air flowing in and out, so an electric arc furnace using a carbon electrode, an electric resistance Even when an electric melting furnace such as a furnace or a plasma melting furnace is used, an explosion accident does not occur and safe processing can be performed without taking explosion-proof measures such as enclosing N ₂ gas.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be specifically described below based on the embodiments shown in FIGS.

As shown in FIG. 1, the soot-dust melting and solidifying apparatus of this embodiment comprises a melting furnace 1, a slag cooling and solidifying apparatus 2 and a soot-dust introducing apparatus 3.

As shown in FIG. 1, the melting furnace 1 is a well-known electric arc in which a dust inlet 4 and an exhaust port 5 and a carbon electrode 6 are provided on the upper wall and a slag discharge port 7 as a gate is provided on the lower portion of the side wall. In the furnace, arc discharge is generated between the electrodes 6 and the base metal 8 on the bottom of the furnace, and the heat generated thereby causes the soot dust 9 charged into the furnace 1 through the charging port 4.
b ... is melted, and the molten slag 9c is overflowed and discharged from the discharge port 7.

As shown in FIG. 1, the slag cooling and solidifying apparatus 2 comprises a cooling water tank 10 for water-sealing the slag discharge port 7 and a water-sealed flight conveyor 12 extending from the cooling water tank 10 onto the slag pit 11. It becomes. Thus, the molten slag 9c discharged from the slag discharge port 7 falls into the cooling water tank 10 and is water-cooled (quenched) to become black sand granules,
Drained by conveyor 12 and then slag pit 1
It is discharged to 1.

As shown in FIGS. 1 to 5, the soot / dust supply device 3 includes a soot / dust supply case 13 connected to the soot / dust input port 4, and a soot / dust supply case 13.
The inside of the case 13 contains a dust pushing chamber 13a and a dust feeding chamber 13
The partition body 14 is divided into b, a pushing body 15 arranged in the dust pushing chamber 13a, and a cutting body 16 arranged in the dust feeding chamber 13b.

As shown in FIGS. 2 to 4, the dust supply case 13 is an L-shaped rectangular tube composed of a horizontal tube portion 13'a and a vertical tube portion 13'b connected to one end thereof. To the other end of the horizontal cylinder portion 13'a, a dust supply hopper 17 communicating with the upper surface opening is connected, and the dust 9a is discharged from the hopper 17 into the horizontal cylinder portion 13'a.
Can be supplied to. In addition, the vertical cylinder portion 13
The lower end of ′ b is connected to the soot / dust input port 4.

As shown in FIGS. 2 to 4, the partition wall body 14 is a thick rectangular plate interposed between the tubular portions 13'a and 13'b, and one end portion of the horizontal tubular portion 13'a and this. The upper end of the vertical tube portion 13'b connected to is completely shielded. The partition wall body 14 is provided with a plurality of circular small-diameter holes 14a ... The thickness of the partition wall 14 and the diameter and shape of the small diameter hole 14a are such that rod-shaped compression molded products 9b and 9'b as described later can be obtained.
4a is arbitrarily set on condition that it is always hermetically sealed with soot dust 9'a. Of course, the number and arrangement of the small diameter holes 14a are also arbitrarily set according to the cross-sectional shape of the dust pushing chamber 13a and the like.

As shown in FIGS. 1 to 3, the pushing member 15 is composed of a pair of screws 15a, 15a arranged in parallel in the dust pushing chamber 13a.
By rotating a and 15a in the same direction at the same speed by the drive motor 18, the soot dust 9a supplied from the hopper 17 to the soot dust pushing chamber 13a is pushed to the partition wall body 14. In other words, the dust pushing chamber 13a is configured as a biaxial screw feeder.

As shown in FIGS. 2 and 3, the cutting body 16 is a rotary shaft 16a rotatably supported by a peripheral wall portion of the vertical cylindrical portion 13'b, which is directly opposed to the partition wall body 14, and a rotary shaft 16a thereof. A plurality of blades 16b are radially attached to the tip end portion in parallel with the partition wall body 14 and are rotationally driven by the drive motor 19 at a relatively slow speed. The length of the soot dust pellet 9b, which will be described later, is determined by the position where the cutting body 16 is arranged, that is, the distance between the blades 16b ... And the partition wall body 14.

In the soot dust melting and solidifying apparatus 1 having the above-described structure, the soot dust 9a is compressed into pellets 9b by the soot dust supplying device 3 and then supplied into the furnace 1 from the soot introducing port 4. To be done.

That is, from the hopper 17 to the dust supply chamber 13
The soot dust 9a ...
is pushed to the partition wall body 14 and is pressed into the small diameter holes 14a of the partition wall body 14 while being compressed, and as the soot dust 9a is further pushed by the conveyors 15a, 15a, the small diameter holes 14a are pushed. Compressed soot inside 9'a
.. gradually pass through the partition wall 14 and are pushed out to the soot / dust input chamber 13b (see FIG. 5 (A)). That is, the partition wall body 14 fulfills the same function as a die in extrusion molding. The soot dust, that is, the rod-shaped compression molded product 9'b, extruded from the small-diameter holes 14a ... When the tips of the soot dust reach the blades 16a of the cutting body 16 (see FIG. 7B), the rotating blades 16a. Is cut (broken) by and is dropped from the soot / dust input chamber 13b to the soot / dust input port 4 (see FIG. 7C). That is, the soot dust pellets 9b having a constant length are quantitatively supplied into the furnace 1.

Dust pellets 9b supplied into the furnace 1 ...
Is melted in the furnace 1 as described above, and the molten slag 9c drops from the slag discharge port 7 into the cooling water tank 10, is cooled and drained, and is then discharged into the slag pit 11. On the other hand, Cd, Pb, H contained in the dust pellet 9b
The low-melting-point substance such as g is volatilized in the furnace 1, is discharged from the exhaust port 5 together with the exhaust gas 9d, is collected by a dust collector or the like, and is subjected to post-treatment such as cement hardening.

At this time, the soot dust 9b supplied from the soot dust inlet 4 into the furnace 1 is in the form of pellets obtained by compressing and solidifying the fine dust soot dust 9a ... There is no. Therefore, as described at the beginning, a part of the input dust is not scattered and discharged from the exhaust port 7 together with the exhaust gas 9d, and the entire input dust can be reliably melted.

Moreover, a partition body 1 for shielding the soot-dust input chamber 1
As shown in FIGS. 5 (A) to 5 (C), the small diameter holes 14a of No. 4 are always filled with the soot dust 9'a in a compressed state, so that the air intrusion from the soot dust inlet 4 is completely completed. Will be blocked. Of course, when the amount of soot dust supplied from the hopper 17 is insufficient or when the hopper 17 becomes empty, that is, the soot dust 9a ... Is not filled in the soot dust pushing chamber 13a, and the soot dust 9a is pushed.
Even when the material seal by ... is not exhibited, as shown in FIG. 5 (D), the small diameter holes 14a of the partition wall body 14 are all blocked by the soot dust 9'a, so that the air intrusion prevention effect is I will not lose anything.

Therefore, in combination with the fact that the slag discharge port 7 is sealed with water, the inside of the furnace 1 is maintained in a completely airtight space, and the special explosion-proof measures as mentioned at the beginning of this are to prevent this. There is no need to take any action.

The structure of the soot dust melting and solidifying apparatus according to the present invention is not limited to the above-mentioned embodiment, and can be appropriately improved or changed within the range not departing from the basic principle of the present invention.

For example, the melting furnace 1 may be of any type, and may be an electric melting furnace other than the electric arc furnace described above, or a fuel-fired melting furnace such as a surface melting furnace. FIG. 6 shows an example in which the present invention is applied to a dust melting and solidifying apparatus using a surface melting furnace. That is, the surface melting furnace 1 supplies the soot dust 9b ... Injected from the soot dust inlet 4 into the furnace 1 by the pusher 21, and melts the soot dust 9b in the furnace 1 from the surface layer portion by the burner 20 on the ceiling. It is configured as follows. A soot dust supply device 3 having the same structure as described above is connected to the soot dust inlet 4 of the surface melting furnace 1, and the rod-like compressed soot dust pellets 9b in a state where air intrusion from the inlet 4 is blocked. ... is supplied from the inlet 4. A slag cooling and solidifying device 2 having the same structure as described above is connected to the slag discharge port 7 of the surface melting furnace 1, and the exhaust port 5 is discharged from the discharge port 7 and the furnace 1 through the discharge port 7.
The cooling water tank 10 seals the exhaust path 5a up to. Even when the surface melting furnace 1 having a large amount of fuel combustion gas is used as compared with the electric melting furnace in this manner, the fine dust 9a
, Is not directly supplied into the furnace 1 but is supplied as a pellet-shaped compression molded product 9b, so that it is not blown up by the burner flame and is discharged together with the exhaust gas 9c without being melted. There is no.

Further, the structure of the soot / dust supply device 3 is not limited to the above embodiment. For example, the pushing body 15 may be something like a pusher instead of the screw 15a as described above. In short, the soot dust 9a supplied from the hopper 17 ...
May be extruded from the small-diameter holes 14a of the partition body 14. By the way, each small-diameter hole 1 of the partition wall body 14
Since the rod-shaped compression molded product 9'b extruded from 4a is a brittle material, when the protrusion amount from the partition wall body 14 becomes a certain amount or more, it is broken by its own weight. Therefore,
The cutting body 16 does not necessarily have to be provided. But,
Providing the cutting body 16 makes it possible to make the lengths of the pellets 9b supplied to the charging port 4 uniform, which is suitable for quantitative supply. Of course, the configuration of the cutting body 16 is also arbitrary,
For example, the rod-shaped compression molded product 9'b protruding from the partition 14 may be cut from the root as a structure in which the partition 14 moves along the surface on the side of the soot-dust input chamber 13b.

[0031]

As is apparent from the above description, in the soot dust melting and solidifying apparatus of the present invention, the fine dust particles are not directly fed to the melting furnace but are compressed into pellets. I am trying to supply it above,
Regardless of the amount of exhaust gas generated in the melting furnace, soot dust is not scattered and is not discharged together with the exhaust gas outside the furnace, and the post-treatment amount is extremely small. Moreover,
Air intrusion from the soot dust inlet of the melting furnace can be reliably prevented by the material sealing effect of the soot dust clogged in the small diameter hole of the partition wall regardless of the amount of soot dust supplied to the soot dust supply device. Combined with the fact that the discharge port is water-sealed, it is possible to keep the inside of the melting furnace in an airtight state at all times, and to avoid the danger of explosion in the presence of air such as in an electric arc furnace. Even if a melting furnace is used, there is no danger of explosion without taking special explosion-proof measures such as enclosing nitrogen gas. Therefore, according to the soot dust melting and solidifying apparatus of the present invention, the soot dust can be melted and solidified extremely efficiently and safely regardless of the type of the melting furnace used. Further, it is possible to continuously supply a fixed amount of soot dust to the melting furnace.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional side view showing an embodiment of a dust melting and solidifying apparatus according to the present invention.

FIG. 2 is a plan view of the main part (dust supply device).

FIG. 3 is a vertical sectional side view of the main part.

4 is a sectional view taken along line IV-IV in FIG.

5 is an enlarged vertical sectional side view of a main part of FIG. 3, illustrating a soot dust supplying operation.

FIG. 6 is a vertical sectional side view corresponding to FIG. 1 showing another embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Melting furnace, 2 ... Slag cooling and solidifying device, 3 ... Soot dust supply device, 4 ... Soot dust input port, 5 ... Exhaust port, 7 ... Slag discharge port,
9a, 9'a, 9b, 9'b ... soot, 9c ... slag, 1
0 ... Cooling water tank, 13 ... Soot supply case, 13a ... Soot pushing chamber, 13b ... Soot loading chamber, 14 ... Partition body, 14a ... Small diameter hole, 15 ... Pushing body, 15a ... Screw conveyor, 1
6 ... Cutting body, 17 ... Dust supply hopper.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location F23G 5/00 ZAB 115 Z F27B 3/19 F27D 7/06 B 7727-4K 15/00 A 7727- 4K

Claims (2)

[Claims] 1. A melting furnace provided with a soot dust inlet and a slag discharge port, a soot dust supply device connected to the soot dust inlet port, and a slag cooling and solidifying device provided with a cooling water tank for sealing the slag discharge port with water. In the soot-dust melting and solidifying apparatus, the soot-dust supply device has a soot-dust supply case connected to the soot-dust input port, and a soot-dust pushing chamber connected to the soot-dust input port and the soot-dust input chamber communicating with the soot-dust input port. Partition into a room,
A partition body having a plurality of small-diameter holes formed therein, and a pusher body disposed in the dust pushing chamber for pushing the soot dust supplied from the hopper and pushing the dust particles from the small-diameter hole of the partition body to the dust feeding chamber. An apparatus for melting and solidifying soot dust, which is characterized in that 2. The soot-dust introducing chamber is provided with a cutting body for cutting the soot-dust rod-shaped molded product extruded from the small-diameter hole of the partition wall body to a predetermined size. Dust melting and solidification processing equipment.