JP3791275B2 - Equipment for cooling and solidifying molten slag - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to equipment for cooling and solidifying molten slag such as molten slag discharged when waste incineration residues such as municipal waste are melted and blast furnace slag generated at a steelworks.
[0002]
[Prior art]
In steelworks, most of the molten slag that is generated is transported to a slag storage site, gradually cooled, and solidified, but some molten slag is subjected to a rapid cooling process in which it is poured into water and cooled directly. . In addition, in the melting treatment facility for waste, as in the case of an ironworks, a slow cooling process in which the molten slag is naturally cooled or a rapid cooling process in which the molten slag is poured into water and directly cooled is performed.
[0003]
In the rapid cooling process of molten slag, in addition to the direct cooling as described above, an attempt by indirect cooling has been made. As for this rapid cooling method by indirect cooling, a technology for supplying and cooling molten slag on a cooled metal body has been proposed, and as an advantage, slag containing no moisture is obtained. It is mentioned that a drying process is not required when it is used in the process.
[0004]
Various techniques have been proposed for the above-described rapid cooling process by indirect cooling. Among them, there is a technique of cooling by supplying molten slag onto a cooled rotating body. In this technique, an operation is performed in which molten slag is supplied and adhered on the outer peripheral surface of a cylindrical rotating body such as a cooled roll or drum, and the cooled and solidified slag is peeled off and discharged. As such a technique, for example, devices disclosed in JP-A-10-287453, JP-A-60-264349, and JP-B-61-8912 are shown.
[0005]
The apparatus described in Japanese Patent Laid-Open No. 10-287453 has a plurality of water-cooled rolls arranged in contact with the outer peripheral surface, and the molten slag generated from a melting furnace such as waste is removed from the above-mentioned water-cooled roll. It is configured to cool down and granulate while dropping onto the plurality of water-cooling rolls in sequence.
[0006]
In the apparatus described in JP-A-60-264349, two cooled rolls are horizontally spaced and a molten slag is supplied between the two rolls. It has become. According to this apparatus, the two rolls rotate in opposite directions so as to engage with each other downward, and the slag is rolled and pushed downward. The extruded slag is then crushed after passing between cooling panels and being cooled again.
[0007]
Further, in the apparatus described in Japanese Patent Publication No. 61-8912, two cooled drums are arranged horizontally in contact with the outer peripheral surface so that molten slag is supplied between the two drums. It has become. According to this apparatus, the two drums rotate in opposite directions so as to lift the molten slag adhering to each other upward, and the adhering slag is pressed by a pinch roll provided at the lower end of the drum and further scraped by a cutter. Taken and discharged.
[0008]
[Problems to be solved by the invention]
However, the above conventional technique has the following problems.
In the apparatus described in JP-A-10-287453, the molten slag is granulated at the same time when it is cooled, so the molten slag must be supplied so as to be dropped. For this reason, the degree to which the outer peripheral surface of the water cooling roll is utilized as a cooling surface is very small, and the processing capacity of the apparatus is small.
[0009]
In the apparatus described in Japanese Patent Application Laid-Open No. 60-264349, slag is rolled from the gap between two rolls and pushed downward, so that the cooling surface of the water-cooled roll is at most 1/4 of the outer peripheral surface. Minute (90 ° minutes), and the degree of utilization of the outer peripheral surface of the roll as a cooling surface is small.
[0010]
Further, in the apparatus described in Japanese Patent Publication No. 61-8912, the slag adhered to the drum and cooled and solidified must be peeled off using a pinch roll or a cutter. Prone to wrinkles. And if the drum with a wrinkle on an outer peripheral surface is used, it will become difficult to peel the slag adhering to the drum further.
[0011]
Furthermore, the composition of the molten slag varies depending on the type of the object to be processed. For example, the residue resulting from incineration of waste such as municipal waste contains salts and metals. In order to effectively use slag obtained by melting the waste, the salt and metals must be below a certain limit. Need to be processed. Further, the state of the discharged slag varies depending on the type of the melting furnace. When the above incineration residue is melted in a type of melting furnace such as a plasma melting furnace, surface melting furnace, or swirling melting furnace, the molten material is discharged without staying in the furnace, so that the molten salt and metal are slag at the same time. It is discharged while mixed in the inside. For this reason, in particular, the slag discharged from the above type of melting furnace contains a large amount of salts and metals, and in addition, the contained salts and metals are mixed in a molten state, It is difficult to reduce the content of these contaminants below a certain limit after the slag has solidified.
[0012]
The present invention provides a cooling and solidification facility for molten slag that solves the above-mentioned problems of the prior art, has a large processing capacity, is easy to peel off the cooled slag, and can obtain slag from which salts and metals have been removed. The purpose is to do.
[0013]
[Means for Solving the Problems]
The above problems are solved by the following invention. According to a first aspect of the present invention, in the cooling and solidification facility for molten slag, the molten slag is supplied and adhered onto the outer peripheral surface of the cooled cylindrical rotating body, and the cooled slag is peeled off and discharged. A pair of cylindrical rotators configured to rotate in a direction in which the portion in contact with the outer peripheral surface is directed upward are disposed horizontally in contact with the outer peripheral surface and spaced from the bottom of the retention tank. The compartment wall is divided into two compartments, a compartment for receiving the molten slag discharged from the melting furnace and a compartment for supplying the received molten slag onto the cylindrical rotating body, and a compartment for receiving the molten slag. In the section where the molten salt in the molten slag floats and the molten metal in the molten slag settles and separates and is supplied onto the cylindrical rotating body, the molten slag from which the molten salt and molten metal are separated is cylindrical. A retention tank is provided for allowing the molten slag discharged from the melting furnace to be retained on the rotating body and then for supplying the molten slag onto the cylindrical rotating body. A thermometer is provided to measure the surface temperature in the vicinity of the separation point of the slag adhering to the slag, and the temperature measurement value of this thermometer is maintained within the range below the melting point of the slag and exceeding the glass transition point. As described above, a controller is provided that receives a signal of a temperature measurement value of the thermometer and sends an instruction signal to increase or decrease the rotational speed of the cylindrical rotating body to the driving unit of the cylindrical rotating body. Yes.
[0014]
According to a second invention, in the first invention, the cooling fluid is sprayed onto the slag peeled off from the cylindrical rotating body, which is configured to control the spraying flow rate of the cooling fluid based on the temperature measurement value. A secondary cooling device for cooling to a temperature range below the transition point is provided .
[0019]
In the cooling and solidifying treatment of molten slag using a cylindrical rotating body, one of the conditions for stable operation is that the slag can be easily separated from the cylindrical rotating body. Therefore, as a result of various tests conducted by the present inventors to find a condition for easily peeling the slag adhering to the cylindrical rotating body, the following knowledge was obtained. That is, when the slag is not sufficiently cooled and still has plasticity, the degree of adhesion between the cooled metal body and the slag is very small. Then, when the cylindrical rotating body attached with the slag having plasticity is rotated and the slag reaches the separation point, the attached slag is easily peeled off.
[0020]
In order to keep the slag adhering to the cylindrical rotating body in a plastic state, the temperature of the outer surface near the separation point of the adhering slag is kept within the range below the melting point of the slag and above the glass transition point. And the slag is in a state of insufficient cooling. If the temperature of the slag is lower than the melting point, the slag is kept in a state of being formed into a strip shape. If the temperature of the slag exceeds the glass transition point, the slag is kept in a plastic state. Since the composition of molten slag varies depending on the generation source and the type of the object to be processed, it is necessary to use values in the composition for the melting point and the glass transition point.
[0021]
The melting point is a temperature measured by the method defined in JIS (K2151). In terms of phenomenon, when the solid slag is heated to raise the temperature, melting and flow start first. It shall refer to temperature. The slag viscosity at this temperature is said to be about 10 ⁵ poise.
[0022]
Although the temperature control of the attached slag varies depending on the composition of the slag, the upper limit temperature is set to a range of about 1200 to 1350 ° C., and the lower limit temperature is set to a range of about 600 to 1000 ° C.
[0023]
In the present invention, the portion where the pair of cylindrical rotators are in contact with the outer peripheral surface rotates upward so as to draw the outline of the morning glory, so the slag adhering to the cylindrical rotator rises. It moves to the outside and then descends and reaches a position (hereinafter referred to as a detachment point) at the same height as the place where the outer peripheral surface is touched. At this position, if the slag is maintained at a temperature having plasticity, the strip-shaped slag formed on the cylindrical rotating body is naturally peeled off from the cylindrical rotating body by its own weight, and hangs down. If the temperature of the slag is lower than the temperature having plasticity, the belt-like slag solidifies and adheres to the shape matching the curvature of the cylindrical rotating body, and the above-described natural peeling is not performed. For this reason, in order to maintain the slag at the separation point at a temperature at which the slag is plastic, the rotational speed of the cylindrical rotating body is changed.
[0024]
In the present invention, the slag is cooled in two stages by the cooled cylindrical rotating body and the secondary cooling device. For this reason, even if the temperature of the slag peeled from the cylindrical rotating body fluctuates, the slag can be easily lowered to a predetermined temperature. And since it can cope with a load fluctuation by this, size reduction of an apparatus can be achieved.
[0025]
In the present invention, a retention tank is provided, and the molten slag discharged from the melting furnace is temporarily retained and then supplied onto the cylindrical rotating body. In this residence tank, while the molten slag discharged from the melting furnace is retained, the melt mixed in the molten slag rises, and the molten metal settles and is separated. For this reason, if the molten salt discharge port and the molten metal discharge port are provided in the retention tank, the molten slag from which the molten salt and the molten metal are separated can be supplied onto the cylindrical rotating body. As described above, the retention tank serves to separate the molten salt and the molten metal from the molten slag supplied to the cylindrical rotating body. The staying tank also has a role of leveling the flow rate when supplying the cylindrical rotating body.
[0026]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a diagram showing an example of an embodiment according to the facility of the present invention. In this embodiment, a water-cooled drum is used as one of the cylindrical rotating bodies for cooling the molten slag. In FIG. 1, 10 is a retention tank for retaining molten slag discharged from the melting furnace and then supplying the molten slag onto a cylindrical rotating body, 20a and 20b are metal water-cooled drums, and 30a and 30b are secondary cooling devices. It is.
[0027]
The staying tank 10 is divided into two sections by a partition wall 11 provided at a distance from the tank bottom, and one A section is a receiving side of the molten slag discharged from the melting furnace, and the other B section is It is the discharge side for supplying molten slag to the water-cooled drum. In the A section, while the molten slag discharged from the melting furnace stays, the molten salt contained therein floats to form the molten salt layer 50, and the molten metal settles to melt the molten metal. Layer 52 is formed. Reference numeral 51 denotes a molten slag layer in which molten salt and molten metal are separated.
[0028]
An induction heating coil 12 is provided on the outer peripheral portion of the retention tank 10 so that the received molten slag can be maintained at a predetermined temperature. Reference numeral 18 denotes a thermometer for measuring the temperature of the staying molten slag.
[0029]
13 is a slag tank for receiving molten slag, 14 is a molten salt outlet, and 15 is a molten metal outlet. The separated molten salt and molten metal are extracted intermittently and processed separately.
[0030]
16 is a discharge port for the molten slag, and 17 is a gate for adjusting the flow rate of the molten slag supplied to the water cooling drums 20a and 20b.
[0031]
Cooling water pipes are incorporated in the water cooling drums 20a and 20b, and a number of spray nozzles for cooling the inner wall are provided. Further, the water sprayed from the spray nozzle is retained in the lower half of the interior, and the lower part is also cooled. The rotating shaft 21 is provided with a flow path for supplying and discharging cooling water. The two water-cooling drums 20a and 20b are arranged horizontally with their outer peripheral surfaces in contact with each other, and rotate in opposite directions as indicated by arrows in the figure, and both of them contact the outer peripheral surfaces upward. Rotate in the direction of rising.
[0032]
In the figure, 19 is a slag tank connected to the molten slag discharge port 16 of the slag supply tank. Reference numeral 25 denotes a weir plate for storing molten slag on the two water-cooling drums 20a and 20b, and is provided in contact with the outer peripheral surfaces of both ends of the water-cooling drums 20a and 20b. Reference numeral 60 denotes molten slag, and 61 denotes slag adhered to the water-cooled drums 20a and 20b.
[0033]
An ultrasonic liquid level gauge 22 measures the liquid level of the molten slag staying on the two water-cooled drums 20a and 20b. The measurement by the liquid level gauge 22 is performed so that the liquid level becomes constant. A signal of the measured liquid level is sent to the controller 23, and then based on this signal. The instruction signal is sent from the controller 23 to the drive unit of the flow rate adjusting gate 17 of the slag supply tank, the flow rate of the molten slag is adjusted, and the liquid level is controlled.
[0034]
Reference numeral 24 denotes an infrared thermometer for measuring the surface temperature of the slag adhering to the water cooling drums 20a and 20b. The thermometer 24 is disposed at a position where the temperature of the slag can be measured in the vicinity of the separation point F. Although the thermometer 24 is disposed only on the one water cooling drum 21a side, the amount of slag adhering to the two water cooling drums 20a and 20b is substantially the same, and the cooling amount is also substantially the same. It can be considered that the temperature of the slag adhering to the two water-cooled drums 20a and 20b is substantially the same.
[0035]
A signal of the temperature measured by the thermometer 24 is sent to the controller 23. And the instruction | indication signal based on this signal is sent to the drive part (not shown) of the water cooling drum 20a, 20b from the controller 23, and the rotation speed of the water cooling drum 20a, 20b is increased / decreased. The amount of cooling of the molten slag by the water cooling drums 20a and 20b is adjusted by increasing or decreasing the rotation speed, and the temperature of the slag adhering to the water cooling drums 20a and 20b is maintained within a predetermined range.
[0036]
The secondary cooling devices 30a and 30b spray the cooling fluid onto the slag 62 peeled from the water-cooling drums 20a and 20b, and cool and solidify the slag 62 to a temperature below the glass transition point. As the cooling fluid, water, air, or the like can be used. In this embodiment, water is used. 31 is a flow meter, and 32 is a spray nozzle for atomizing and spraying water.
[0037]
In the secondary cooling devices 30a and 30b, a signal from the controller 23 based on the measurement value (temperature before secondary cooling) by the thermometer 24 is sent to the flow meters 31 and 31, and the flow rate of the sprayed water is controlled. .
[0038]
As described above, the secondary cooling in this embodiment is direct cooling in which water is sprayed as a cooling fluid, and the cooling efficiency is very good. Therefore, the temperature of the slag can be greatly reduced by spraying a small amount of water. Can do. Further, the adjustment of the cooling amount in this cooling is performed by changing the flow rate of the sprayed water, and the cooling amount can be changed greatly only by changing the flow rate of the water. For this reason, even if the temperature of the slag peeled from the cylindrical rotating body fluctuates significantly, the slag can be easily lowered to a predetermined temperature.
[0039]
As described above, the present invention has a configuration in which two methods consisting of indirect cooling in which a strip-shaped slag is formed by a cooled cylindrical rotating body and direct cooling by spraying a cooling fluid are combined. Even if slag that fluctuates or the supply amount of molten slag fluctuates and the degree of insufficient cooling is separated, it can be cooled and solidified by spraying the cooling fluid to cope with load fluctuations be able to.
[0040]
In addition, since the cooling and solidification equipment of the present invention has a very large processing capacity, the equipment can be downsized and the site area required for cooling and solidifying the molten slag can be greatly reduced.
[0041]
40a and 40b are crushers provided below the water cooling drums 20a and 20b, and crush the slag that has been cooled and solidified by water spray.
41 is a conveyor for conveying the crushed slag to a process of performing sieving processing, grinding processing (rounding) and the like.
[0042]
The process of cooling and solidifying the molten slag by the equipment having the above-described configuration is performed as follows.
[0043]
The molten slag discharged from the melting furnace is received in the A section of the retention tank 10. Here, the molten salt contained in the received molten slag rises, and the molten metal settles and accumulates at the bottom of the tank. The molten slag from which the molten salt and the molten metal are separated is supplied from the B section to the water-cooled drums 20a and 20b through the slag tank 19. At this time, based on the liquid level height of the molten slag measured by the liquid level gauge 22, the flow rate adjusting gate 17 of the staying tank is adjusted so that the liquid level is maintained constant. Is done.
[0044]
On the rotating water cooling drums 20a and 20b, the slag near the outer peripheral surface is cooled and adheres to the water cooling drum. The adhering slag rises, then moves outward and descends. The surface temperature of the slag 61 adhering to the water-cooling drums 20a and 20b is measured by the thermometer 24, and based on this temperature measurement value, the temperature of the adhering slag 61 is maintained within a plastic range. The number of rotations of the water cooling drums 20a and 20b is controlled, and the cooling amount of the attached slag 61 is adjusted. Thus, since the adhered slag 61 is held in a plastic state, when the adhered slag 61 reaches the separation point F, the slag is separated from the water-cooled drums 20a and 20b by its own weight and hangs down in a belt shape. Therefore, the cooling of the slag in this apparatus is performed between the contact points of the two water-cooling drums 20a and 20b and the separation point F, and 1/2 of the outer peripheral surface is used as the cooling surface.
[0045]
Since the peeled slag 62 is still insufficiently cooled and not solidified, water is sprayed on the slag to quench it. The flow rate of water sprayed from the secondary cooling devices 30 a and 30 b is controlled based on the temperature of the slag 61 measured by the thermometer 24.
[0046]
The solidified slag is crushed by the crushers 40a and 40b and then conveyed to the next process by the conveyor 41.
[0047]
In the temperature control of the slag 61 adhering to the water-cooling drums 20a and 20b, the temperature in the thickness direction of the slag 61 formed in a strip shape is not constant, and the internal temperature is determined from the temperature of the outer surface measured by the thermometer 24. Since the temperature is higher, it is necessary to adopt an appropriate temperature value based on the operation result when setting the control temperature.
[0048]
In the embodiment shown in FIG. 1, the number of rotations of the water cooling drums 20a and 20b and the flow rate of the cooling fluid in the secondary cooling devices 30a and 30b are controlled based on the temperature measured by the thermometer 24. However, in the present invention, it is not always necessary to provide a control mechanism for automatically adjusting the number of rotations of the water cooling drum and the flow rate of the cooling fluid.
[0049]
That is, the change in the number of rotations of the water-cooling drums 20a and 20b is performed in order to change the cooling amount of the attached slag and keep the slag in a temperature range having plasticity. The temperature control range is the range from the melting point of the slag to the glass transition point, the upper limit temperature is expected to be 1200 to 1350 ° C., the lower limit temperature is about 600 to 1000 ° C., and the temperature range is Very wide. For this reason, when the temperature fluctuation of the supplied molten slag is not so large, the temperature of the attached slag can also be adjusted by manually adjusting the rotation speed of the water cooling drums 20a and 20b according to the situation. Can be kept in range. Moreover, if the temperature of the slag peeled off from the water cooling drum is within the above range, the temperature fluctuation during that time is adjusted by cooling by the secondary cooling devices 30a and 30b.
[0050]
The cooling of the slag by the secondary cooling devices 30a and 30b is an operation performed to rapidly cool and solidify the slag separated from the water-cooling drums 20a and 20b, and to reduce the size of the device. It depends on the processing conditions. For example, in the case of only cooling to a temperature that does not hinder the operation of the subsequent process, the object can also be achieved by performing an operation of manually adjusting the flow rate of the cooling fluid according to the situation. it can.
[0051]
【The invention's effect】
According to the present invention, since the slag adhering to the cylindrical rotating body is held in a plastic state, the slag cooled by the cylindrical rotating body can be peeled off and discharged very easily.
[0052]
Further, since the slag is cooled in two stages by the cylindrical rotating body and the secondary cooling device, the processing capacity is large and load fluctuations can be dealt with.
[0053]
In addition, a retention tank is provided to retain the molten slag before being supplied onto the cylindrical rotating body, so that the molten salt contained in the molten slag discharged from the melting furnace is levitated and the molten metal is allowed to settle. Can be separated. For this reason, the content of inclusions is very small, and a slag that can be effectively used for civil engineering and building materials is obtained.
[Brief description of the drawings]
FIG. 1 is a diagram showing an example of an embodiment according to the facility of the present invention.
[Explanation of symbols]
10 Residence tank 11 Partition wall 12 Induction heating coil 13 Slag tank for receiving molten slag,
14 Molten salt outlet 15 Molten metal outlet 16 Molten slag outlet 17 Flow rate control gate 18 Thermometer 19 Slag gutter 20, 20b Water-cooled drum 21 Water-cooled drum rotating shaft 22 Liquid level gauge 23 Controller 24 Temperature 25 Melting Dam plate 30a, 30b for storing slag Secondary cooling device 31 Flow meter 32 Spray nozzle 40a, 40b Crusher 41 Conveyor 50 Molten salt layer 51 Molten slag layer 52 Molten metal layer 60 Molten metal slag 61 Adhered slag 62 Exfoliated slag

Claims (2)

In the cooling and solidification equipment for molten slag that supplies and adheres molten slag to the outer peripheral surface of the cooled cylindrical rotating body and peels and discharges the cooled slag, it can be cooled and is in contact with the outer peripheral surface A pair of cylindrical rotators configured to rotate in a direction toward the upper side are horizontally disposed in contact with the outer peripheral surface, and provided with a space between the bottom of the retention tank The wall is divided into two sections, a section for receiving the molten slag discharged from the melting furnace and a section for supplying the received molten slag onto the cylindrical rotating body. In the section for receiving the molten slag, In the section where the molten salt floats and the molten metal in the molten slag settles and separates and is supplied onto the cylindrical rotating body, the molten slag from which the molten salt and molten metal are separated is supplied onto the cylindrical rotating body. A retention tank configured to allow the molten slag discharged from the melting furnace to be retained and then to be supplied onto the cylindrical rotating body; and further, a slag attached to the cylindrical rotating body is provided. and a thermometer is provided for measuring the surface temperature in the vicinity of the withdrawal point, as maintained in the range of temperature measurements of the thermometer exceeds the glass transition point below溶流point of the slag, the temperature A controller for sending an instruction signal for increasing / decreasing the rotational speed of the cylindrical rotating body to the driving section of the cylindrical rotating body in response to a temperature measurement signal of the meter , Cooling and solidification equipment.   2. The cooling and solidification facility for molten slag according to claim 1, wherein the cooling fluid is sprayed onto the slag separated from the cylindrical rotating body configured to be able to control a spraying flow rate of the cooling fluid based on the temperature measurement value. A cooling and solidification facility for molten slag, wherein a secondary cooling device for cooling to a temperature range below the glass transition point is provided.

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