JPH0541890B2 - - Google Patents

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention is applicable to incineration ash discharged from incinerators that incinerate municipal garbage, sewage sludge, and general waste, as well as boilers, kilns, and industrial applications that use coal as fuel. The present invention relates to a processing device that melts coal ash discharged from a furnace or the like, and then cools and solidifies the molten slag by air cooling or water cooling at a desired cooling rate while continuously conveying the molten slag.

[Conventional technology]

In recent years, boilers, kilns, industrial furnaces, etc.
From the perspective of reducing fuel costs, conversion from oil and gas fuel to coal fuel is being actively promoted. On the other hand, the amount of coal ash that remains after burning this coal is also increasing as the amount of coal consumed is increasing, and there is a need to dispose of this coal ash. In addition, there is a need to dispose of the incinerated ash discharged from incinerators for municipal waste, sewage sludge, etc., and conventionally, most of the ash has been disposed of by landfilling. has been done.

[Problem that the invention seeks to solve]

However, in recent years, it has become difficult to secure a landfill site for the ash, and disposal standards have become stricter from the perspective of preventing marine pollution caused by harmful substances. The problem is that it is difficult. Therefore,
Nowadays, post-treatment of the above ash has become a very important issue.

Therefore, in order to effectively utilize the ash, the applicant melted the ash and then cooled it to solidify it.
Reduction of disposal volume, immobilization of hazardous substances such as heavy metals,
Furthermore, we proposed an ash processing device that allows the generated slag to be used as a material for civil engineering and construction.
62-187453). FIG. 5 shows the processing device,
This mainly consists of a vertical melting furnace 1 and a combustion air supply device 6 that supplies combustion air to the melting furnace 1.
and an ash supply device 7 that supplies ash to the melting furnace 1.

The combustion air supply device 6 supplies combustion air preheated to a predetermined temperature to combustion air supply pipes 6a and 6b.
This is a device that supplies the above-mentioned melting furnace 1 with the above-mentioned melting furnace 1. Although not shown, the ash supply device 7 is a device in which an ash storage bottle is connected to a quantitative feeder, and a predetermined amount of ash is automatically cut out from the feeder and transported by pneumatic flow to the melting furnace 1. It is.

The melting furnace 1 is constructed by connecting a fuel inlet 3 to the upper end of a cylindrical furnace body 2 with a flange, and detachably connecting a slag pot 4a of an ash collecting part 4 to the lower end. Further, the furnace main body 2 has a combustion chamber 2a formed in its upper part, a constricted part 2b at the outlet of the combustion chamber 2a, and a constricted part 2b.
An exhaust gas outflow part 2c is integrally formed at the lower part of the
The extended end of the exhaust gas outlet 2c is connected to a chimney (not shown). Furthermore, a secondary air blowing part 8 is formed in the upper part of the combustion chamber 2a,
The blowing portion 8 is configured to blow combustion air from the combustion air supply pipe 6b into the combustion chamber 2a in a tangential direction.

Further, an auxiliary combustion burner 5 is connected to the fuel inlet 3, and the burner 5 has a solid gas two-phase flow supply pipe 5b and a fuel supply pipe 5c at the upper part of the main body 5a.
It is configured by connecting. The combustion air supply pipe 6a is connected to the solid gas two-phase flow supply pipe 5b, and the ash supply pipe 7a of the ash supply device 7 is connected to the middle of the supply pipe 6a. As a result, the ash is mixed into the combustion air, and this solid-gas two-phase flow passes through the solid-gas two-phase flow supply pipe 5b and is given a strong swirl by the swirling vanes disposed inside the burner main body 5a. , is injected into the furnace body 2. Further, a fuel supply device 9 is connected to the extended end of the fuel supply pipe 5c.

When the ash is melted and solidified in the above processing equipment, fuel gas and a part of the combustion air preheated to a predetermined temperature are blown into the furnace body 2 from the auxiliary combustion burner 5 and combusted, and the temperature of the furnace wall is adjusted to the temperature of the ash. Maintain above melting temperature. Next, in this state, a predetermined amount of ash is air-transported and mixed into the combustion air. Then, the solid-gas two-phase flow in which the combustion air and ash are mixed is given a strong swirling flow when passing through the burner body 5a, and is uniformly injected into the combustion chamber 2a. As a result, the ash forms a spiral and collides with the furnace wall due to the centrifugal force, causing rapid combustion.The ash A, which has become a molten slag, falls under its own weight and enters the slag pot 4.
It is collected in a.

In the above processing apparatus, when the molten slag A collected in the slag pot 4a is crystallized, the supply of ash is stopped and the slag pot 4a is removed after being kept in this state for several hours to slowly cool it. , and then take out the slag.

When the molten slag A is to be made into glass, the operation of the melting furnace 1 is stopped, the slag pot 4a is immediately removed, the slag is rapidly cooled in the open air, and the slag is taken out.

Furthermore, if the molten slag A is to be made into powdered water slag, a water-cooled slag pot 4b is connected to the lower end of the furnace main body 2, as shown in FIG.
A water tank 10 is provided at the bottom of this, and the molten slag A is dropped into the water tank 10, and then taken out by a conveyor 11.

According to the above processing device, the ash can be melted,
By solidifying the slag, it is possible to reduce the amount to be disposed of, fix harmful substances such as heavy metals, and effectively utilize the generated slag as a material for civil engineering and construction. However, in the above processing apparatus, when the molten slag collected in the slag pot 4a is slowly cooled or rapidly cooled with air, the operation of the melting furnace 1 must be temporarily stopped. Therefore, continuous operation is required from the viewpoint of improving productivity.

In addition, when using water cooling, continuous extraction is possible, but the water in the water tank 10 evaporates due to falling molten slag and heat transfer of combustion exhaust gas, and this water vapor causes a temperature drop in the lower part of the furnace body 2. , and the amount of exhaust gas from the flue may increase, so there is room for improvement.

Furthermore, when switching from air cooling to water cooling to generate water slag, it is necessary to replace the water-cooled slag pot 4b with a water tank 10, etc. each time, and from this point of view as well, improvements in workability are required. ing.

The present invention has been made in view of the above-mentioned conventional situation, and an object of the present invention is to provide a processing device that can effectively utilize molten ash slag into a desired secondary product and can significantly improve productivity. There is.

[Means for solving problems]

Therefore, the present invention provides incinerated ash and coal that are made by converting urban garbage, sewage sludge, and general waste incinerated ash and coal ash (hereinafter referred to as ash) into molten slag, and then cooling and solidifying the slag while continuously transporting it. The ash processing apparatus includes a melting furnace for melting the ash, a slag part formed at the lower part of the melting furnace and discharging the molten slag, and a slag part for burning the molten slag in the slag part. A heat retaining means that maintains the molten slag at the melting temperature by the sensible heat of the exhaust gas and a number of bucket-shaped molds are arranged so as to move below the slag outlet, and the molten slag falling from the slag is collected. A conveying device that is housed in the mold and sequentially conveyed, and at least an upper portion of the conveying device is covered with an insulating hood, and the inside of the mold is maintained at a predetermined temperature state by introducing combustion exhaust gas into the hood. A heat retention device,
A control device for controlling the conveying speed of the conveying device so that the cooling rate of the conveyed molten slag becomes a predetermined speed, and a cooling water supply means for supplying a predetermined amount of cooling water into each of the molds. It is characterized by

Here, as the heat retention means, the inside of the melting furnace may be brought into a positive pressure state, the combustion exhaust gas in the furnace may be jetted out to the above-mentioned slag outlet, and the sensible heat may be used to heat the melting furnace. It is also conceivable to introduce combustion exhaust gas into the slag part and heat it by forming a weir that reduces the flue area in the exhaust gas passage of the melting furnace. Note that it is also possible to combine an auxiliary burner with the use of the sensible heat of the combustion exhaust gas.

Further, the above-mentioned conveying device may be configured such that a large number of bucket-shaped molds are disposed on an endless chain conveyor, and the molds move below the above-mentioned slag discharge portion, so that the molten metal is melted in each mold. The slag may be dropped, the molten slag may be cooled and solidified while being conveyed one by one, and the solidified slag may then be taken out. In order to solidify the molten slag collected in this mold at a desired cooling rate, for example, the chain conveyor, that is, the upper part of each mold is covered with an insulating hood to keep the inside of each mold warm. For example, by controlling the rotation speed and interval of the conveyor, the amount of slag collected in the mold can be changed, thereby changing the cooling rate of the molten slag, or the mold can be filled with water in advance. This can be achieved by keeping the molten slag cooled and dropping it into this cooling water. In this case, the cooling rate of the molten slag is set to 5
A crystallized slowly cooled slag can be obtained by slow cooling to less than 5°C/min.
By quenching at a temperature of min or more, a glassy quenched slag can be obtained. By further cooling with water, a powdered water slag is obtained.

[Effect]

According to the incineration ash and coal ash processing apparatus of the present invention, the molten slag is kept at the melting temperature and cooled and solidified while being conveyed continuously, so that the amount of ash to be disposed of can be reduced, and the amount of heavy metals Because it can immobilize harmful substances such as, it can pass disposal standards and be disposed of in a landfill, and it can also be effectively used as aggregate for construction.

In addition, in the present invention, since a heat retention means is provided in the slag outlet, the discharged slag can be maintained at a temperature of a viscosity that has sufficient fluidity, and as a result, clogging of the slag outlet due to a drop in the temperature of the slag is prevented. can. Since the continuously discharged molten slag is cooled while being transported, the melting furnace can be operated continuously for a long period of time, and productivity can be greatly improved. In this case, there is no need to replace the slag pot as described above, so work efficiency can be improved.

Moreover, since air cooling (slow cooling, rapid cooling) or water cooling can be freely selected using the same conveyance device, desired secondary products such as glass-like or powder-like products can be easily produced.

In addition, the water vapor generated when water slag is generated by water cooling can be prevented from entering the melting furnace by the jet of combustion exhaust gas from inside the furnace, which reduces the temperature drop in the lower part of the furnace body and increases the amount of exhaust gas. It can be avoided.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 are diagrams for explaining an apparatus for treating incineration ash and coal ash according to an embodiment of the present invention, and in the figures, the same reference numerals as in FIG. 5 indicate the same or corresponding parts.

In the figure, 12 is a processing device of this embodiment, and this processing device 12 includes a combustion air supply device 6,
A melting furnace 1 equipped with an ash supply device 7, a slag extraction part 15 connected to the lower part of the melting furnace 1, and an auxiliary burner 16 as a heat retention means disposed in the slag extraction part 15. , and a conveying device 17 that continuously conveys the molten slag discharged from the slag discharge section 15 and cools and solidifies it.

The melting furnace 1 has an auxiliary combustion burner 5 disposed at the upper end of a furnace body 2 which is integrally formed with a combustion chamber 2a, a throttle part 2b, and an exhaust gas outlet part 2c, and the basic structure is shown in FIG. 5 above. It is the same as the melting furnace.

The slag outlet section 15 is connected to the lower end of the furnace main body 2, and is lined with degenerated bricks. This slag discharge part 15 has an angle θ formed with the horizontal plane.
The discharge passage 15a is inclined at an angle of 5 degrees or more.
A slag outlet 15b extending vertically downward is integrally formed at the lower end of the passage 15a. Further, an exhaust gas outlet 15c is formed at the lower part of the slag outlet 15b, and a burner insertion hole 15d is formed in a portion of the discharge passage 15a facing the connecting portion with the slag outlet 15b. Inside this insertion hole 15d is a nozzle 16 of the auxiliary burner 16.
A is attached to the burner 16, and a fuel supply pipe 16b and a combustion air supply pipe 16c are connected to the burner 16. As a result, the slag at the slag outlet 15b is maintained at a melting temperature by heat radiation from the peripheral wall and flame from the auxiliary burner 16.

Further, the upper end of a falling duct 23 that can be raised and lowered is connected to the lower end of the slag outlet 15b, and the lower end of the duct 23 is positioned so as to be able to come into contact with the upper surface edge of the mold 19, which will be described later, of the transport device 17. are doing. The duct 23 substantially seals between the slag outlet 15b and the mold 19 to prevent outside air from entering, and also transfers combustion exhaust gas from the melting furnace 2 and the slag outlet 15 to the conveying device 17. This prevents the molten slag from coming into contact with the outside air and causing its fluidity to drop suddenly.

The conveying device 17 is constructed by attaching a large number of molds 19 at a predetermined pitch to an endless chain conveyor 18, and is supported in an inclined state by a support frame 20. A drive motor 21 is disposed at the lower end of the conveyor 18, so that the conveyor 18 is driven clockwise in the figure. Furthermore, a slag container 22 is provided below the upstream end of the conveyor 18 to collect solidified slag. The mold 19 has a heat insulating material 1 on the outer surface of the tub body 19a made of iron plate.
9b attached thereto, thereby increasing the heat retention effect of the molten slag.

Furthermore, a heat insulating hood 24 is disposed on the chain conveyor 18 so as to cover the upper part of each mold 19. This heat insulating hood 24 has a heat insulating material 24b attached to the outer surface of a hood main body 24a made of a thin steel plate, which allows the slag to be slowly cooled by keeping it warm using the sensible heat of the exhaust gas and molten slag. It is configured as follows. Further, a duct hole 24c is formed in the heat insulating hood 24, and the drop duct 23 is provided in the duct hole 24c.
is inserted. In addition, 25 is an insulating hood 24
This is the outlet for exhaust gas and water vapor inside.

Furthermore, between the insulating hood 24 on the downstream side of the conveying device 17 and the chain conveyor 18,
A cooling water supply pipe 26 is inserted, so that cooling water can be supplied into the mold 19 from the discharge port 26a.

Next, the ash processing process by the processing device 12 of this embodiment will be explained.

First, the ash melting process will be explained. By the combustion of the auxiliary burner 5, the furnace wall temperature of the melting furnace 1 is heated and maintained at a temperature higher than the melting temperature of the ash, and the ash 150 is heated and maintained in the melting furnace 1.
A solid-gas two-phase flow of Kg/hr and combustion air is swirled and injected. Then, the ash rapidly burns while swirling in a spiral pattern, falls under its own weight, becomes molten slag, and flows down to the lower part of the furnace body 2.

Next, the steps of cooling and solidifying the molten slag will be explained.

The molten slag that has flowed down to the bottom of the furnace body 2 is
The slag flows through the discharge passage 15a of the slag outlet 15 and reaches the outlet 15.
b, passes through the falling duct 23 and is collected in the mold 19. The molten slag collected in the mold 19 is transported by the chain conveyor 18 and solidified by air cooling or water cooling at a predetermined cooling rate, and then stored in the slag container 22.

Here, in the slag outlet 15b, the auxiliary burner 16 burns heavy oil 8.9/hr at an air ratio of 1.2, and this flame is blown onto the slag outlet 15b, so that the slag outlet 15 is Melting furnace 1
Due to the heat radiation inside and the amount of heat from the auxiliary burner 16, the heat is maintained at a temperature higher than the melt flow temperature of the slag. Therefore, the molten slag has an amount of heat (approximately
500 kcal/Kg), and since the discharge passage 15a is inclined, the slag is continuously discharged without blocking the outlet port 15b due to temperature drop. Moreover, since the lower end of the duct 23 descends and comes into contact with the periphery of the mold 19,
Since the slag does not come into contact with the outside air and falls together with the combustion exhaust gas, there is no sudden drop in fluidity. Furthermore, the conveyor 1
Since a heat insulating hood 24 is disposed above the mold 8, the molten slag in the mold 19 is kept warm by the sensible heat of the slag and the combustion exhaust gas introduced from the duct 23.

Next, while the conveying device 17 conveys the molten slag collected in the mold 19,
A method for continuously producing slowly cooled slag, rapidly cooled slag, and water slag will be described.

First, when manufacturing slowly cooled slag, the drive motor 21 is rotated so that the amount of slag stored in each of the molds 19 is 10, and the transportation time until it is stored in the slag container 22 is 1 hour. Set the number and interval. As a result, 5℃/
The slag is slowly cooled at a slow cooling rate of less than 10 min, and a slowly cooled slag with advanced crystallization is obtained.

When producing rapidly cooled slag, the rotational speed and interval of the drive motor 21 are doubled so that the amount of slag in the mold 19 is 5 and the transport time is 30 minutes. As a result, the slag is rapidly cooled at a cooling rate of 5° C./min or more, and glassy quenched slag is obtained without crystallization.

Next, when manufacturing a water slag slag, the lowermost mold 19 is filled with cooling water in advance during an interval, and the molten slag is dropped into the cooling water.
As a result, the slag is pulverized and a water slag slag with a particle size of several mm is obtained. In this case, the water vapor evaporated by the sensible heat of the slag is pushed out by the exhaust gas from the dart 23, rises along the upper wall of the insulating hood 24 without entering the melting furnace 2, and is discharged from the exhaust port 25. Therefore, the slag part 15
temperature drop will not occur.

In this way, according to the device 12 of this embodiment, the ash is turned into molten slag in the melting furnace 1, and this is cooled and solidified, so that the amount of ash to be disposed of can be reduced, and the harmful substances contained in the ash can be reduced. Since the material can be solidified, it can be landfilled and used as aggregate for construction.

Further, in this embodiment, an auxiliary burner 16 is attached to the slag extraction part 15 to maintain the molten slag at a melting temperature, and the molten slag from the slag extraction part 15 is collected in the mold 19 and conveyed to the conveyor 18. Since the slag pot is solidified at a desired cooling rate while being conveyed continuously, there is no need to replace the slag pots, etc., which improves work efficiency.
can be operated continuously for long periods of time, greatly improving productivity.

Furthermore, in this embodiment, the cooling rate can be changed by controlling the conveyance speed of the conveyor 18, which allows the production of secondary products such as slow cooling, rapidly cooling slag, or water slag slag from molten slag. can also be selected freely.

FIG. 3 is a characteristic diagram showing the experimental results of the relationship between the temperature drop of molten slag and the conveyance time. In this experiment, 10 pieces of molten slag were placed in the mold 19 without the heat insulating material 19b installed, and taken out after being transported for 1 hour (curve A), and 5 pieces of slag were placed in the mold 19 and the mold 19 was taken out for 30 minutes. The cooling rate and the properties of the solidified slag were investigated when the slag was taken out after being transported (curve B). In addition, the above mold 1
The cooling rate and properties of the solidified slag were also investigated under the same conditions in the case where the heat insulating material 19b was installed on No. 9 (curves A' and B'). As a result, when 10 slags were transported in 60 minutes without applying insulation material 19b (curve A), and when 10,5 and insulation material 19b was applied (curves A', B'), In both cases, the cooling rate was 5° C./min or less, and in each case, slowly cooled slag with advanced crystallization was obtained. On the other hand, when 5 slags were transported in 30 minutes without installing the above-mentioned heat insulating material 19b (curve B), the cooling rate was 5°C/min or more, and glass-like rapidly cooled slag was obtained. . As is clear from this,
When producing the above-mentioned slowly cooled slag, the slag is collected at a cooling rate of 5°C/min or less, and when producing rapidly cooled slag, the slag is collected at a cooling rate of 5°C/min or more. All you have to do is adjust the amount and the rotation speed of the conveyor.

In addition, although the above-mentioned example explained the case where the auxiliary burner 16 as a heat retention means was arranged in the slag extraction part 15, the arrangement position etc. of the heat retention means of this invention are limited to this. It's not a thing. FIG. 4 shows a modification of the heat retaining means, in which an auxiliary burner 30 is attached to the furnace body 2 side of the melting furnace 1, and the burner 30
This is an example in which the nozzle 30a is directed along the inclined discharge passage 15a, and a dam part 31 is formed protruding from the upper end of the slag part 15 to block a part of the exhaust gas outflow part 2c. According to this, melting furnace 1
Since the outflow amount of the combustion exhaust gas inside is restricted by the weir section 31, a part of the exhaust gas is introduced into the slag outlet section 15, and the auxiliary burner 3
0 can be made unnecessary, or the combustion amount of the burner 30 can be reduced to approximately half. Further, the inside of the melting furnace 1 may be brought into a positive pressure state and the combustion exhaust gas may be introduced into the slag outlet 15. In this case as well, the effect of reducing the combustion amount of the burner can be obtained.

〔Effect of the invention〕

As described above, according to the incineration ash and coal ash processing apparatus according to the present invention, a slag discharge part for discharging molten slag is formed in the lower part of the melting furnace for melting ash, and a heat retention means for the slag is arranged. The system is equipped with a conveying device that continuously conveys and cools and solidifies the molten slag from the slag, which has the effect of effectively using the ash as a secondary product, and also allows the ash to be continuously melted and solidified. , it has the effect of improving productivity and workability.

[Brief explanation of the drawing]

Fig. 1 is a schematic configuration diagram for explaining an ash processing device according to an embodiment of the present invention, Fig. 2 is a sectional view showing the mold, and Fig. 3 is a characteristic showing the relationship between slag temperature and conveyance time. 4 are cross-sectional views showing a modification of the slag discharge portion of the above-mentioned embodiment, and FIGS. 5 and 6 are cross-sectional side views showing a processing apparatus for explaining the process of establishing the present invention, respectively. In the figure, 1 is a melting furnace, 15 is a slag extraction part, 1
6 and 30 are auxiliary burners (heat retaining means), and 17 is a conveying device.

Claims (1)

[Claims] 1. A treatment device for incinerated ash and coal ash that melts urban garbage, sewage sludge, and general waste incinerated ash and coal ash (hereinafter referred to as ash) into slag, and then cools and solidifies the slag while continuously transporting it. A melting furnace for melting the ash, a slag part formed at a lower part of the melting furnace and discharging the molten slag, and a slag discharger from the slag part to be transferred to the sensible heat of combustion exhaust gas of the melting furnace. A heat retaining means for maintaining the slag at the melting temperature and a large number of bucket-shaped molds are arranged so as to move below the slag outlet, and the molten slag falling from the slag is transferred into the mold. A conveying device that accommodates and sequentially conveys the mold, and at least an upper portion of the conveying device is covered with an insulating hood, and combustion exhaust gas from the melting furnace is introduced into the insulating hood to maintain the inside of the mold at a predetermined temperature state. a control device that controls the conveyance speed of the conveyance device so that the cooling rate of the conveyed molten slag becomes a predetermined speed; and a cooling water supply that supplies a predetermined amount of cooling water into each of the molds. An apparatus for processing incineration ash and coal ash, characterized by comprising: means.