JP2005226939A - Slag treating method and treating apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a slag treating method and treating apparatus capable of effectively suppressing the formation of acicular slag while avoiding the danger of phreatic explosion to efficiently treat slag in a system for treating slag formed based on waste or the like. <P>SOLUTION: In granulating slag, at least one granulating water jetting means 6 disposed in plane shape is used to form a stream of predetermined flow velocity to a predetermined depth including the water surface position where the slag falls in a water tank of its own weight. At this time, it is preferable that the stream has flow velocity within a range of 0.5-2 m/s on the water surface. It is also preferable to arrange a plurality of granulating water jetting means 6 perpendicularly to the water surface of the water tank. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a slag treatment method and a treatment apparatus, and more particularly to a technique for granulating molten slag.

  Generally, in waste treatment facilities, a pyrolysis gasification melting furnace or a combination of a waste incinerator and an ash melting furnace is used. By bringing molten slag into contact with cooling water, the slag is cooled and solidified. The solidified slag is granulated (hereinafter referred to as “water granulation”). In other words, slag after such treatment (hereinafter referred to as “granulated slag”) is used as a raw material for asphalt, building aggregate, concrete fine material, tetrapot (trade name), etc. In order to facilitate handling, it is useful to make slag fine particles by water granulation. Specifically, the case where it uses as an aggregate can be mentioned on the basis of a particle size of 5 mm or less.

  Recently, several proposals have been made for such a method of granulating slag. For example, as shown in FIG. 5, while detecting the position of the molten slag flow flowing down by the slag flow position detecting means 52 so that the water for granulation can be accurately sprayed on the molten slag flow 51, There is a method of spraying cooling water (granulated water) onto the slag from a nozzle 53 provided between the slag falling start point and the water surface (see, for example, Patent Document 1).

Further, as shown in FIG. 6, an inclined plate 62 is disposed below the slag discharge port 61, and a water injection nozzle 63 for injecting water is provided on the upper surface of the inclined plate 62, and water is injected into the molten slag in the middle of dropping. And the method (refer patent document 2) which adjusts properties, such as the particle size of a slag, intensity | strength, a shape, by controlling the injection quantity is proposed.
Japanese Patent Laid-Open No. 5-201753 Japanese Patent Laid-Open No. 10-54537

  However, in the above proposal, it is not always easy to make the amount of falling slag constant. When the cooling water is directly applied to the molten slag, the following problems may occur.

  (1) When the cooling water injection amount is small, the slag falls into the water tank at a high temperature, and there is a risk of steam explosion on the water surface.

  (2) When the injection speed is high, liquid slag is entrained in the water flow and cooled, so a large amount of needle-like slag is generated. Therefore, there is a problem in safety when handling granulated slag, A separate grinding process is required.

  (3) When needle-shaped slag is crushed and converted into a granular material, the handling becomes easy as a fine-grained slag, while the amount of fine powder generated increases, and the content when used in aggregates, etc. Inconvenience that adjustment becomes difficult occurs, and the necessity of dust processing from the viewpoint of the working environment or the increase in the complexity of conveyance are generated.

  Accordingly, an object of the present invention is to efficiently treat slag while avoiding the danger of water vapor explosion and effectively suppress the occurrence of acicular slag in a system for treating slag generated based on waste. An object of the present invention is to provide a slag treatment method and a treatment apparatus that can be used.

  As a result of intensive studies, the present inventors have found that the above object can be achieved by the processing method and processing apparatus described below, and have completed the present invention.

  The present invention is a method for treating slag, and includes a surface including a water surface position at which the slag falls by its own weight in a water tank, using at least one granulated water jetting means arranged in a flat shape when the slag is granulated. And a water flow having a predetermined flow velocity is formed to a predetermined depth including the water surface.

The present inventor, in the formation of granulated slag, the element that determines the granular slag,
(1) When the high-temperature liquid slag cools, a surface solidified layer is generated.
(2) The solidified layer is split on the surface and peeled off.
(3) The phenomenon of (1) and (2) occurs on the new surface that appears after peeling.
In order to realize this mechanism,
(1) The slag is in contact with a predetermined amount of granulated water, that is, it is preferably in contact with the granulated water in a plane with the slag surface, and cooling in the water tank is preferable to spraying the granulated water in the air.
(2) The crushed water in contact with each other is sequentially replaced, and a certain range of heat transfer on the slag surface can always be ensured, that is, the movement of crushed water in a direction different from the falling direction of the slag is preferable.
(3) In particular, the state of (1) and (2) is ensured up to the water surface where the high-temperature slag first contacts the granulated water and to a certain depth close to the surface.
I found that it was necessary.

  That is, by forming at least one planar water flow controlled to a predetermined injection amount and having a predetermined flow velocity from the water surface to a certain depth, the surface of the hot slag falling into the water flow The granular solidified product can be sequentially accumulated in the water tank. Furthermore, since heat transfer on the surface of the high-temperature slag can be secured by this, it is possible to prevent a steam explosion associated with contact with water.

  The slag treatment method is characterized in that the water flow has a flow velocity in the range of 0.5 to 2 m / sec on the water surface.

  As described above, in order to prevent a steam explosion associated with the contact of high-temperature slag with granulated water, which is one of the problems of the present invention, it is important to ensure heat transfer on the surface of the high-temperature slag. The higher the flow rate, the higher the effect. On the other hand, if the flow velocity is high, the possibility of generating needle slag is high, and it is not suitable for forming granular slag, which is another problem of the present invention. As a result of verification of this problem, the present inventor is that the flow velocity of the surface of the granulated water where the high-temperature slag and the granulated water first contact each other is the most important factor, and the surface flow velocity is controlled within a predetermined range. Thus, the present inventors have found that it is possible to realize a slag treatment method capable of avoiding the danger of steam explosion and effectively suppressing the occurrence of acicular slag with high reproducibility.

  The slag treatment method is characterized in that a plurality of the granulated water jetting means are arranged in a direction perpendicular to the aquarium water surface.

  The amount of slag generated in a waste treatment facility or the like is not always constant, and it may be difficult to sufficiently control the surface flow velocity as described above within a predetermined range with one granulated water jetting means. As shown in the present invention, by arranging a plurality of crushed water spraying means arranged in a plane and spraying crushed water from any means, the controllable range is expanded and the optimum surface flow velocity is secured. can do.

  In the above slag treatment method, if there is an amount of water jetted from the crushed water jetting means or / and a plurality of jetting means depending on the output from the flow velocity measuring means of the water flow, the jetting means is selected. It is characterized by controlling.

  As described above, in order to solve the problem in the present invention, it is important to maintain the surface of the granulated water that is first contacted with the high-temperature slag and the granulated water in a predetermined state. In the case of having a plurality of injection means, such a state can be ensured by controlling selection of the injection means. Specifically, it is preferable to provide a means for measuring the surface flow velocity, and input this output signal to the controller to control the crushed water jetting means and the amount of water jetted.

  The present invention is a slag processing apparatus, characterized by using the above-described slag processing method.

  All of the above processing methods ensure the formation of granular slag, suitable handling, and can effectively suppress the steam explosion associated with the contact between the high-temperature slag of the granulated slag and the granulated water. An excellent slag processing apparatus can be configured.

  As described above, according to the present invention, there is provided a slag processing method and a processing apparatus capable of efficiently processing slag while avoiding the danger of steam explosion and effectively suppressing the occurrence of acicular slag. be able to. In addition, since the granular slag can be formed while avoiding the generation amount of fine powder, handling becomes easy, while the working environment or the load of conveyance can be greatly reduced.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  A schematic overall structure of a slag processing apparatus according to an embodiment of the present invention is illustrated in FIG. The melted material 1 such as incineration residue is supplied to the melting furnace 2 and melted, and then the melted material is granulated in a water tank 3 filled with granulated water to form granular slag, which is carried out by the slag conveyor 4. The

  In FIG. 1A, a plasma arc melting furnace is illustrated. A plasma cathode E (−) is disposed at the furnace top, a plasma anode E (+) is disposed at the furnace bottom, and arc discharge is performed on the melt 1. As a result, the melt (slag) is stored at the bottom of the melting furnace 2 at a high temperature of 1200 to 1600 ° C. When the formed slag exceeds a certain amount, it sequentially falls from the outlet of the melting furnace 2 to the water tank 3 filled with cooling water through its slide portion 5 by its own weight. The slide portion 5 is preferably provided with a groove portion having a V-shaped or U-shaped cross section as shown in FIG. 1B so that the slag moves smoothly. Granulated water injection means 6 is provided on the wall surface of the water tank 3, and a predetermined flow rate of the granulated water is discharged, and a predetermined flow velocity is given to the water surface and a predetermined depth with respect to the water surface and its peripheral part where the slag enters. The water stream which has is formed.

  At this time, the molten slag in a high temperature state of 1300 ° C. or higher is rapidly cooled at the moment of contact with the granulated water, and at the same time as a surface solidified layer is generated, it is split and separated. A similar phenomenon occurs on the new surface that appears as a result of the surface peeling, and the slag falling in the water repeats such division sequentially and gradually becomes smaller in diameter and then becomes finer as a whole.

  The water flow formed in the water tank 3 is always in contact with the surface of the slag at a predetermined flow rate, so that such cooling, splitting, and separation are easily repeated. At the same time, by forming a water flow perpendicular to the falling direction of the slag, it is possible to increase the physical load on the slag surface and promote peeling. Furthermore, not only the water flow only on the surface layer of the water surface but also the water flow up to a predetermined depth makes it possible to make finer particles easier. FIG. 2 illustrates a state in which granular slag is formed by splitting and peeling off such slag. In particular, slag generated in a waste treatment facility or the like is mainly composed of silica or alumina, and the addition of temperature and mechanical strain is very effective.

  In the present invention, the amount of crushed water used for the treatment varies depending on the amount of the material to be melted or the target substance, but for the material to be melted mainly containing an ash component in a waste treatment facility, for example, About 30 times the maximum capacity of the furnace is sufficient, but an apparatus capable of supplying about 30 to 100 times of granulated water is preferable in order to cope with a rapid increase in falling molten slag.

  In addition, when high-temperature slag comes into contact with still water, there is a possibility of causing a steam explosion associated with rapid moisture transpiration. The water flow formed in the water tank 3 can prevent the risk of such a steam explosion at the same time as the formation of the granular slag as described above. Even for slag immersed in water, the state that does not fall below 1000 ° C is maintained up to a certain depth, so the possibility of causing a steam explosion associated with boiling of water on the slag surface and rapid transpiration of water disappears. However, the formation of a water flow to a predetermined depth is also useful for avoiding such danger.

  Ideally, it is preferable that the amount of slag fall is substantially uniform. However, in practice, the amount of the melt 1 is often repeatedly increased or decreased temporarily. It is not necessarily a certain range. In the present invention, as such correspondence, it is possible to produce a highly uniform granular slag by forming a water flow in a planar shape in a range having a predetermined spread around the vertical position C of the tip of the slide portion 5. It has become possible. For stable flow control of the water flow, it is preferable that the injection from the granulated water injection means 6 is planar, and it is particularly central by uniformly injecting from the granulated water injection means 6 having a plurality of injection ports. It is also possible to increase the stability of the flow rate at the section. Specifically, as illustrated in FIG. 3, it is preferable to form a water flow on the entire surface of the slag in which the slag can be diffused around the position C on the water surface.

  Specifically, the water flow rate preferably has a range of 0.5 to 2 m / sec on the water surface. For a water flow of less than 0.5 m / sec, there is a possibility of a steam explosion associated with the contact of high-temperature slag with granulated water, which is one of the problems of the present invention, while 2 m / sec. When the water is crushed by the excess water flow, the possibility of generation of acicular slag, which is another problem of the present invention, is increased. In response to these two issues, the surface flow rate of the granulated water where the high-temperature slag first contacts with the granulated water is the most important solution. The granular slag can be generated with good reproducibility. That is, such surface flow velocity can effectively suppress the generation of acicular slag while ensuring heat transfer on the surface of the high-temperature slag.

  Moreover, although the water temperature of a water flow can be used at about normal temperature, it is calculated | required that it is 55 degrees C or less from a viewpoint of the safety | security of operation. However, the lower the temperature, the easier the slag can be split and crushed by contact with the granulated water, and the risk of steam explosion can be reduced. Accordingly, the water temperature is preferably about 30 ° C. or less, for example, and more preferably 10 ° C.

  In FIG. 1, the apparatus which circulates and uses the water after carrying out the water granulation process of the slag in the water tank 3 is illustrated. Here, the crushed water overflowed from the water tank 3 is stored in the water tank 7 for injection, and is sequentially cleaned by the filter 8 or the like, cooled by the heat exchanger 10 by the pump 9, and then again from the water crushed water injection means 6 It is supplied to the water tank 3. Of course, it is also possible to prevent the generation of deposits and deposits in the apparatus by sequentially replacing part of the circulating water with clean water. The heat exchanger 10 is connected to a refrigerant flow path that separately forms a circulation system including a cooling pump 11 and cools the granulated water.

  The water tank 3 is provided with a water temperature measuring means 12 and a water flow velocity measuring means 13. As the water temperature measuring means 12, any means such as a contact type such as a thermocouple or a non-contact type such as a radiation thermometer can be used. As the flow velocity measuring means 13, any means such as an immersion type such as an electromagnetic flow meter or a non-contact type such as an ultrasonic flow meter can be used. In any case, it is preferable to use a radiation thermometer or an ultrasonic flowmeter capable of obtaining two-dimensional information from the aspect of monitoring the state of the granulated water. Further, when measuring and controlling not only the surface flow velocity but also the underwater flow velocity, it is possible to provide not only one flow velocity measuring means 13 but also a plurality or a combination of a contact type and a contact type. is there.

  Next, an embodiment in which a plurality of the granulated water injection means 6 as illustrated in FIG. 4 are arranged in the vertical direction with respect to the water surface of the aquarium will be described. The granulated water is connected to the granulated water injection means 6a, 6b, 6c,... Via a plurality of control valves 14a, 14b, 14c,. In FIG. 4, one crushed water jetting means 6 a is on the water surface, the crushed water jetting means 6 b is arranged on the water surface, and the other crushed water jetting means 6 c. Needless to say, it is not limited.

  As described above, in the present invention, the flow velocity on the water surface is the most effective for the formation of granular slag and the prevention of water vapor explosion, but the amount of slag generated in a waste treatment facility is not always constant, It may be difficult to sufficiently control the surface flow velocity as described above within a predetermined range with the crushed water jetting means. As shown in FIG. 4 (A), a plurality of stages of granulated water jetting means 6a, 6b, 6c,... Are arranged so that the granulated water can be jetted from any means. By using the auxiliary, the controllable range can be expanded and the optimum surface flow velocity can be secured.

  Specifically, the relationship between the amount of water sprayed and the flow velocity changes depending on the depth position from the water surface, and the deeper the flow velocity, the greater the stability of the flow velocity and the influence of water surface changes such as slag falling. Therefore, it is preferable to perform stable control of the surface flow velocity by the amount of injection from the injection means in the water rather than the water surface. For example, as shown in the broken line part of FIG. 4 (B), the flow rate of each part can be adjusted as indicated by the solid line part in FIG.

  Further, since the water flow rate in the water tank 3 is also deeply involved in the formation of granular slag, the correlation with the surface flow rate which is the optimum condition is obtained in advance, and the granulated water injection means 6a, 6b, 6c,. It is also preferable to control and maintain the flow velocity in the depth direction of the granulated water. Alternatively, manual control can be performed while confirming whether or not needle-like slag is generated in an actual operation state.

  In the present invention, granular slag having an arbitrary shape can be formed by controlling the surface flow velocity and the flow velocity in water. In other words, slag with a small particle size can be formed when the surface flow velocity is close to the upper limit range, and slag with a small particle size can be formed by approaching the lower limit range. Slag can be produced arbitrarily, and the use expansion of slag can be aimed at.

  It is also useful to change the control value depending on the type of the material to be melted. For example, when a large amount of silica, alumina, or the like is included, the surface flow velocity range is slightly shifted to the lower limit range because the heat capacity is small, and when a large amount of iron is included, the surface flow velocity range is increased because the heat capacity is large. It is preferable to shift slightly to the upper limit range side. At the same time, in the former case, a granular slag having a uniform shape can be formed by slightly reducing the flow velocity on the water surface and increasing the flow velocity in water, and in the latter case, the opposite is true. In the present invention, such a highly versatile control method can be applied.

  Here, each of the crushed water spraying means 6a, 6b, 6c,... Has a plurality of spray ports in a plane, and as shown in FIG. The three-dimensional flow velocity control around the water surface position C can be performed, and the danger of steam explosion and the generation of acicular slag can be avoided more accurately.

  In this apparatus, the amount of water ejected from the crushed water jetting means 6 or the water jetting quantity of the plurality of jetting means 6a, 6b, 6c,... Is controlled by the output from the flow velocity measuring means 13 of the water flow provided in the water tank 3. It is preferable to do. That is, as described above, in order to solve the problem in the present invention, it is important to maintain the surface of the granulated water, which is first contacted with the high-temperature slag and the granulated water, in a predetermined state. By obtaining such information by means 13 and adjusting the amount of sprayed granulated water based on this information, the optimum state of the surface of the granulated water can be ensured. In addition, it is also useful to control the injection amount based on the output from the water temperature measuring means 12 to avoid the danger of steam explosion and the generation of acicular slag.

  Furthermore, by using such a control method, it is also possible to adjust the spray amount of the granulated water according to the processing amount of the molten slag, and by controlling the water flow while managing the surface flow velocity according to the processing amount. It is possible to produce a granular slag having a uniform desired shape.

  In all of the above treatment methods, the risk of steam explosion and the generation of acicular slag can be avoided with good reproducibility by preparing granulated slag from melted materials such as waste. By having the crushing means, a very excellent slag processing apparatus can be configured. That is, according to the present invention, it is possible to provide a slag processing apparatus that can form a highly uniform granular slag and can produce a granulated slag excellent in handling such as conveyance.

  As described above, the embodiment of the present invention has been described by taking the material to be melted from the waste treatment facility as an example of the processing object, but the object to which the present invention can be applied is limited to this. It may be various slags, for example, copper slag generated during copper refining or iron slag discharged from a blast furnace.

Explanatory drawing which shows the processing method of the slag which concerns on one Embodiment of this invention. Explanatory drawing illustrating the situation where granulated slag is produced from molten slag Explanatory drawing which illustrates the state of the water flow which concerns on embodiment of this invention Explanatory drawing which shows the processing method of the slag which concerns on other embodiment of this invention. Explanatory drawing which shows the processing method of one slag which concerns on a prior art Explanatory drawing which shows the processing method of the other slag which concerns on a prior art

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Melted material 2 Melting furnace 3 Water tank 4 Slag conveyor 5 Slide part 6 Granulated water injection means 13 Flow velocity measuring means

Claims (5)

  When the slag is subjected to the water granulation treatment, at least one plane of the granulated water jetting means is used, and the slag has a planar shape including a water surface position where the slag falls by its own weight in the water tank, and to a predetermined depth including the water surface. And forming a water flow having a predetermined flow velocity.   The slag treatment method according to claim 1, wherein the water flow has a flow velocity in the range of 0.5 to 2 m / sec on the water surface.   The slag treatment method according to claim 1 or 2, wherein a plurality of the crushed water jetting means are arranged in a direction perpendicular to the water surface of the aquarium.   According to the output from the flow velocity measuring means of the water flow in the water tank, the amount of water jetted from the crushed water jetting means or / and the selection of the jetting means in the case of having a plurality of jetting means are controlled. The processing method of the slag in any one of Claims 1-3. The processing method in any one of Claims 1-4 is used, The processing apparatus of the slag characterized by the above-mentioned.

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