JP3884676B2 - Operation control device for rotary kiln - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an operation control device for a rotary kiln that burns and melts an object to be processed while rotating.
[0002]
[Prior art]
2. Description of the Related Art A rotary kiln is known that burns and melts waste by heating with a heating device and discharges it as molten slag while moving the introduced waste from the inlet side to the outlet while rotating.
[0003]
The molten slag discharged from the rotary kiln has been effectively used for civil engineering materials such as asphalt pavement, for example, by water cooling or air cooling. For this reason, recently, it has been required to stably produce uniform and high-quality molten slag, and in order to satisfy this requirement, it is necessary to set the combustion melting temperature of waste to the optimum temperature. Since there are various types of wastes and their properties are different, it is difficult to maintain the combustion melting temperature optimally, and uniform and high-quality molten slag cannot be stably obtained.
[0004]
Therefore, in order to solve the above problem, the temperature in the rotary kiln that varies according to various wastes is actually measured by a temperature detector such as a thermocouple, and the heating by the heating device is controlled based on this measured temperature. A technique for temperature has been proposed.
[0005]
Recently, a technique has also been proposed in which molten slag is imaged with a camera or the like without installing a temperature detector, the temperature is automatically determined from the luminance and color tone, and heating by the heating device is controlled.
[0006]
[Problems to be solved by the invention]
However, when using the former temperature detector, it is difficult to withstand use in a harsh environment at high temperature, it is difficult to use for a long period of time, and frequent replacement is required. It is impossible to adopt.
[0007]
In addition, when using the latter camera, etc., dust such as fly ash is scattered, so it is difficult to accurately capture the brightness and color tone in the image, and the temperature can be determined with high accuracy. It is extremely difficult and therefore operation at a suitable temperature cannot be expected.
[0008]
The present invention has been made in order to solve such problems, and can be automatically operated at a suitable temperature for a long period of time regardless of the workpiece to be introduced. An object of the present invention is to provide an operation control device for a rotary kiln in which slag can be stably obtained.
[0009]
[Means for Solving the Problems]
Here, as a result of intensive investigations by the present inventors, the flow position of the molten slag from the rotary kiln outlet and the viscosity of the molten slag are closely related, and the viscosity of the molten slag and the temperature of the molten slag Therefore, if a relationship of (melted slag flow position)-(information on molten slag temperature) is obtained in advance according to the object to be processed, the molten slag flow position is determined based on this relationship. Thus, it has been found that information on the molten slag temperature corresponding to the object to be processed is obtained, and heating of the heating device can be suitably controlled based on this information.
[0010]
Accordingly, the operation control device of the rotary kiln according to the present invention burns and melts the workpiece by heating by the heating device and discharges it as molten slag from the outlet while moving the workpiece to be introduced from the inlet side to the outlet while rotating. An apparatus for controlling the operation of a rotary kiln that images an image of molten slag flowing down from an outlet, and is preset in accordance with the type of object to be processed (melted slag flowing position)-(information on molten slag temperature) ) Based on the relationship between the type of workpiece to be introduced and the imaged molten slag flow position, information on the molten slag temperature is obtained, and the heating device is heated based on the information on the obtained molten slag temperature. And a processing means for controlling.
[0011]
According to the operation control device of the rotary kiln configured in this way, the temperature is judged from the brightness and color tone of the molten slag that does not require the installation of a temperature detector that is difficult to withstand harsh environments at high temperatures and is difficult to accurately capture in that environment. Based on the relationship of (melted slag flow position)-(information on molten slag temperature) set in advance according to the type of the object to be processed without using the technique of performing the processing, the image is captured by the imaging device by the processing unit. Information on the molten slag temperature corresponding to the type of the object to be processed is grasped from the molten slag flow position, and heating by the heating device is controlled based on this information.
[0012]
Here, the processing means is set in advance according to the type and properties of the object to be processed, and based on the relationship of (melting slag flow position)-(information on the molten slag temperature), Information on the molten slag temperature may be grasped from the properties and the imaged molten slag flow position, and heating of the heating device may be controlled based on the grasped information on the molten slag temperature. Specific examples of the information on the molten slag temperature include a molten slag temperature or a molten slag viscosity.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a preferred embodiment of an operation control device for a rotary kiln according to the invention will be described with reference to the accompanying drawings. FIG. 1 is a partial cross-sectional configuration diagram illustrating a melting facility including an operation control device for a rotary kiln according to an embodiment of the present invention, and FIG. 2 illustrates a relationship between a molten slag viscosity and a molten slag temperature according to an object to be processed. FIG. 3 is a diagram showing the flow-down melting slag from the outlet imaged by the imaging device in FIG. 1, and FIG. 4 is a flowchart showing the processing procedure of the processing means in FIG. The equipment is used in a pyrolysis gasification and melting system that pyrolyzes and melts garbage such as general waste and industrial waste, and a furnace that is generated by pyrolysis and gasification of waste in a gasification furnace. The object to be treated such as bottom ash (hereinafter referred to as incineration ash) is burned and melted and recovered as molten slag.
[0014]
As shown in FIG. 1, the melting facility 1 includes a rotary kiln 2 as a rotary melting furnace and a secondary combustion tower 3 communicated with the rotary kiln 2.
[0015]
The rotary kiln 2 is a so-called short kiln in which a furnace having a cylindrical shape is arranged substantially horizontally and furnace length (L) / furnace diameter (D) <5. The rotary kiln 2 is disposed so as to incline downward from a front part (left side in the figure) on the inlet side to a rear part (right side in the figure) on the outlet side, and the front end part is a front part as a fixed part. It is closed by the support portion 4 and is rotatably supported, and its rear end portion is inserted into the secondary combustion tower 3 as a fixed portion and is rotatably supported.
[0016]
The front support part 4 includes an introduction duct 5 that penetrates the front support part 4 and introduces an object to be processed from the upstream side into the furnace. The rotary kiln 2 rotates at a predetermined speed, The workpiece to be processed is conveyed from the front part on the inlet side toward the outlet 6 on the rear end face.
[0017]
A heating device 7 is disposed on the front support portion 4. The heating device 7 includes a fuel combustion device 7a such as a burner that is introduced into the furnace through the front support portion 4, and a plurality of combustion air that passes through the front support portion 4 and introduces combustion air into the furnace. A supply nozzle 7b.
[0018]
The fuel combustion device 7a burns kerosene as fuel using the combustion air from the combustion air supply nozzle 7b, and the high-temperature combustion gas and flame generated by this fuel combustion are the moving direction of the workpiece ( In the same direction as from the left side to the right side in the figure, the rotary kiln 2 rotates and comes into contact with the workpiece to be moved from the front to the rear to burn and melt the workpiece.
[0019]
In this embodiment, the fuel combustion device 7a using kerosene as fuel is employed, but a fuel combustion device using other liquid fuel as fuel may be employed, and thermal decomposition from a gasifier is also possible. A fuel combustion apparatus that uses gaseous fuel such as gas as fuel may be employed. Further, the fly ash char accompanying the pyrolysis gas from the gasification furnace is separated and the separated fly ash char or the like is separated. A fuel combustion apparatus using solid fuel as fuel may be employed.
[0020]
The outlet 6 of the rotary kiln 2 is a common outlet for molten slag and combustion exhaust gas generated by combustion and melting of the workpiece in the furnace, and the secondary combustion tower 3 is connected to the outlet 6.
[0021]
The secondary combustion tower 3 includes a secondary combustion chamber 9 that communicates with an upper side of the outlet region 8 that communicates with the outlet 6 on the side opposite to the outlet 6. In the secondary combustion chamber 9, the combustion exhaust gas discharged from the outlet 6 is subjected to secondary combustion by introducing secondary combustion air. A dust discharge duct 10 that guides the scattered dust such as fly ash downward is connected to the lower side of the secondary combustion chamber 9, and the scattered dust is introduced into the introduction duct 5 of the rotary kiln 2 at the lower portion of the dust discharge duct 10. A dust discharge conveyor 11 is installed to convey the product so as to return to the position.
[0022]
Further, the secondary combustion tower 3 is provided with a slag cooling water tank 12 immediately below the outlet region 8 for rapidly cooling the molten slag flowing down from the outlet 6 and recovering it as a granulated slag and sealing the furnace side. The slag cooling water tank 12 is provided with a slag conveyor 13 that conveys the granulated slag in the tank to the outside of the tank.
[0023]
In addition, the melting facility 1 includes an operation control device 20 that optimally controls the operation of the rotary kiln 2. The operation control device 20 includes an imaging device 14, a processing unit 15, and a RAM 16 and a ROM 17 as storage units.
[0024]
The imaging device 14 is, for example, a monitoring camera or the like, is installed on a wall facing the outlet 6 of the secondary combustion tower 3 and faces the outlet 6, and images the molten slag flowing down from the outlet 6.
[0025]
The processing means 15 is constituted by a CPU, and based on the image information captured by the imaging device 14, the fuel amount and combustion of the fuel combustion device 7a are optimized so that the heating of the heating device 7 is optimized according to the object to be processed. The amount of combustion air in the industrial air supply nozzle 7b is controlled.
[0026]
Here, the function of the processing means 15 will be specifically described. First, an outline thereof will be described. As a result of intensive investigations by various experiments, the present inventors have found that the flow position of the molten slag from the rotary kiln outlet 6 and the viscosity of the molten slag are closely related, and the viscosity of the molten slag and the temperature of the molten slag are For this reason, if the relationship between the molten slag flow position-molten slag viscosity and the relationship between molten slag viscosity-molten slag temperature are determined in advance according to the object to be processed, imaging is performed based on this relationship. It has been found that the temperature in the rotary kiln 2 can be optimized if the molten slag temperature corresponding to the object to be processed is known from the molten molten slag flow position and the heating of the heating device 7 is controlled based on the molten slag temperature. .
[0027]
Accordingly, it is necessary to obtain the relationship between the molten slag flow position-melt slag viscosity and the relationship between molten slag viscosity-molten slag temperature in advance before operation. Specifically, various processed objects are prepared, and molten slag generated for each of the various processed objects is put into a test container such as a crucible and kneaded, and the torque when kneading the molten slag is, for example, Using a torque meter or the like, this is converted into a viscosity, and a molten slag viscosity that fluctuates using the molten slag temperature as a variable is obtained. The relationship between the molten slag viscosity and the molten slag temperature is as shown in FIG. Obtain as a data table for each item.
[0028]
Here, in this embodiment, incineration ash that is considered to be introduced with a large amount of actual equipment, a combination of incineration ash and bulky waste (mixing ratio 3: 2), a combination of incineration ash and incineration sludge as the object to be treated. (Mixing ratio 9: 1) is mentioned, incineration ash alone is indicated by a solid line, a mixture of incineration ash and oversized waste is indicated by a dotted line, and a mixture of incineration ash and incineration sludge is indicated by a one-dot chain line. In addition, the oversized garbage said here means the oversized garbage (for example, furniture, a broken cup etc.) after crushing to below predetermined size with a crusher. Then, the operator stores the relationship between the molten slag viscosity and the molten slag temperature (hereinafter referred to as a viscosity / temperature relationship) corresponding to the workpiece in the RAM 16 in advance.
[0029]
Further, as shown in FIG. 3B, when the molten slag flow down position is 1/3 of the radius in the rotational direction from the center of the outlet, the molten slag viscosity is the viscosity of the coordinate B shown in FIG. When the molten slag flow down position is 2/3 of the radius from the center of the outlet in the rotational direction as shown in FIG. 3A, the molten slag viscosity is shown in FIG. When the viscosity of the coordinate A is high (high viscosity) and the molten slag flow-down position is located at the center of the outlet as shown in FIG. 3C, the molten slag viscosity is the value of the coordinate C shown in FIG. Viscosity (low viscosity). Further, when the molten slag flow down position is deviated from the position shown in FIG. 3, the molten slag viscosity increases or decreases from the molten slag viscosity at coordinates A, B, and C shown in FIG. The operator also stores the relationship between the molten slag flow position and the molten slag viscosity (hereinafter referred to as the flow position / viscosity relationship) in the RAM 16 in advance.
[0030]
Then, the processing means 15 uses the above relationships stored in advance in the RAM 16 to grasp the molten slag viscosity corresponding to the object to be processed from the molten slag flow position imaged by the imaging device 14, and this molten slag viscosity. Then, the molten slag temperature corresponding to the object to be processed is grasped, and the heating of the heating device 7 is optimally controlled based on the molten slag temperature. For example, when an operator, an operator, or the like selects an object to be introduced with an input switch, for example, which data table is used is automatically selected.
[0031]
Next, the processing procedure of the processing means 15 executed according to the program written in the ROM 17 will be described with reference to the flowchart shown in FIG.
[0032]
Here, incinerated ash (water content 30%) is introduced into the rotary kiln 2 through the introduction duct 5 at 500 kg / h as an object to be treated. Prior to operation, an operator, an operator, or the like selects incineration ash as an object to be processed using, for example, an input switch.
[0033]
When the operation is started, the object to be processed moves from the inlet side to the outlet side while being agitated according to the rotation of the furnace. At this time, it is exposed to the high-temperature combustion gas and flame by the heating device 7 and burns and melts. The molten slag is discharged from the outlet 6, and the imaging device 14 images the molten slag flow position.
[0034]
Here, the imaging device 14 is in a high temperature and severe environment where fly ash is scattered, and it is difficult to accurately capture the brightness and color tone of the molten slag. It is easy to catch.
[0035]
First, in step 401 (S401), the molten slag viscosity is grasped from the flow position / viscosity relationship based on the selected object to be processed and the imaged molten slag flow position. Here, when the molten slag flow position deviates from the position shown in FIG. 3, as described above, the molten slag viscosity is changed from the slag viscosity of coordinates A, B, and C shown in FIG. Increase or decrease.
[0036]
In step 402 (S402), the molten slag temperature is grasped from the relationship between viscosity and temperature based on the selected object to be processed and the obtained molten slag viscosity.
[0037]
Specifically, when the treatment object is incinerated ash, the solid line shown in FIG. 2 is used, and if the molten slag viscosity is the molten slag viscosity at the coordinate A shown in FIG. 2, the molten slag temperature is about 1240 ° C. If the material to be treated is a mixture of incineration ash and incineration sludge, use the alternate long and short dash line shown in FIG. 2, and the melt slag viscosity should be the melt slag viscosity at coordinates C shown in FIG. In this case, the molten slag temperature is determined to be about 1400 ° C.
[0038]
In step 403 (S403), it is determined whether or not the molten slag temperature exceeds the target temperature range of 1300 ° C. to 1350 ° C., and if so, in step 404 (S404), depending on the degree of the increase, Control is performed to reduce the amount of fuel in the fuel combustion device 7a and the amount of combustion air in the combustion air supply nozzle 7b to reduce heating, and the process proceeds to step 405 (S405).
[0039]
On the other hand, if it is determined in step 403 (S403) that the molten slag temperature does not exceed the target temperature range of 1300 ° C to 1350 ° C, the target of the molten slag temperature of 1300 ° C to 1350 ° C is determined in step 406 (S406). In step 407 (S407), the amount of fuel in the fuel combustion device 7a and the amount of combustion air in the combustion air supply nozzle 7b are determined in accordance with the degree of lowering in step 407 (S407). Control is performed to increase and increase the heating, and the process proceeds to step 405 (S405).
[0040]
In Step 406 (S406), when it is determined that the molten slag temperature does not fall below the target temperature range of 1300 ° C to 1350 ° C, the molten slag temperature is at the target temperature, so the process proceeds to Step 405 (S405). In step 405, it is determined whether or not the operation is stopped. If the operation is stopped, the process is terminated. If the operation is continued, the process returns to step 401 (S401). In addition, when the workpiece to be introduced changes, for example, an operator, an operator, or the like selects the workpiece to be changed with, for example, an input switch or the like, thereby changing the data table selected by the processing means 15.
[0041]
As described above, the present embodiment uses a technique that determines the temperature from the luminance and color tone of the molten slag that does not require the installation of a temperature detector that cannot withstand a severe environment at a high temperature and that is difficult to accurately capture in that environment. Without being changed, the processing unit 15 causes the imaging device 14 to determine the relationship between the (melted slag flow position−melted slag viscosity) and the (melted slag viscosity−molten slag temperature) relationship that are set in advance according to the object to be processed. From the captured molten slag flow position, the molten slag temperature corresponding to the object to be processed is grasped, and based on this, the heating by the heating device 7 is controlled. Therefore, regardless of the object to be introduced, at a suitable temperature Automatic operation is carried out over a long period of time, and uniform and high-quality molten slag can be stably obtained.
[0042]
The present invention has been specifically described above based on the embodiment. However, the present invention is not limited to the above embodiment. For example, in the above embodiment, the molten slag flow position-the molten slag viscosity, the molten slag The viscosity-melting slag temperature is grasped by using a data table, but may be grasped by calculation.
[0043]
In addition, since the relationship between the molten slag flow position-molten slag viscosity-molten slag temperature is known, the molten slag temperature may be directly grasped from the molten slag flow position, or the melting grasped from the molten slag flow position. The heating may be controlled using the slag viscosity, and further, the melting slag temperature may be converted into the temperature inside the rotary kiln, the outlet temperature of the rotary kiln, etc., and the heating may be controlled using these. The heating may be controlled based on the relationship between the information regarding the molten slag flow position and the molten slag temperature.
[0044]
In the above embodiment, both the fuel amount and the combustion air amount of the heating device 7 are controlled. However, if the heating control is sufficiently performed, only one of them is controlled. May be.
[0045]
In the above-described embodiment, the fuel combustion device 7a and the combustion air supply nozzle 7b are separated from each other. However, for example, a fuel combustion device such as a burner in which a combustion air supply system is integrated is used. It is also applicable to. Further, the supply from the nozzle is not limited to combustion air, but may be any oxygen-containing gas.
[0046]
Moreover, in the said embodiment, although the application with respect to the parallel flow type rotary kiln 2 with which the flow of combustion gas and a flame, and a to-be-processed object becomes the same direction, the flow of combustion gas, a flame, and to-be-processed object is described. The present invention can also be applied to a counter-current type rotary kiln that faces each other.
[0047]
In the above embodiment, the application to the short kiln is described. However, the present invention can be similarly applied to a so-called long kiln in which the furnace length (L) / furnace diameter (D)> 20.
[0048]
Further, in the above-described embodiment, it is particularly preferable that the workpiece to be introduced is incineration ash, a combination of incineration ash and oversized waste, or a combination of incineration ash and incineration sludge, but it is of course limited to these. It is not a thing and the mixing ratio is not limited. For example, municipal waste, solid fuel (RDF), slurry fuel (SWM), automobile waste (shredder dust, waste tire) , Biomass waste, sewage sludge, plastic waste (including FRP), home appliance waste, special waste (medical waste, etc.), manure, high-concentration waste liquid, industrial sludge, backfill ash, wood waste, fiber waste, food waste, etc. Waste, coal, and the like, and any combination thereof, and any combination with the incineration ash, oversized waste, incineration sludge, and the like may be used.
[0049]
Furthermore, for a workpiece whose properties change due to differences in seasons, for example, the difference (melted slag flow position)-(information on molten slag temperature) is the same even if the workpiece is the same. For example, it is possible to obtain in advance according to the season or the like, and to use the relationship depending on the season or the like.
[0050]
【The invention's effect】
The operation control device for a rotary kiln according to the present invention uses a technology that determines the temperature from the brightness and color tone of the molten slag that does not require the installation of a temperature detector that cannot withstand a severe environment at high temperatures and that is difficult to accurately capture in that environment. Without being based on the relationship of (melting slag flow position)-(information regarding molten slag temperature) set in advance according to the type of the object to be processed, the processing means from the molten slag flow position captured by the imaging device, Since the information on the molten slag temperature corresponding to the type of the object to be processed is grasped and the heating by the heating device is controlled based on this information, the temperature is suitable regardless of the object to be processed. Automatic operation is possible over a long period of time, and a uniform and high-quality molten slag can be stably obtained.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional configuration diagram illustrating a melting facility including an operation control device for a rotary kiln according to an embodiment of the present invention.
FIG. 2 is a diagram showing a relationship between a molten slag viscosity and a molten slag temperature according to an object to be processed.
3 is a diagram illustrating a molten slag flowing down from an outlet imaged by the imaging apparatus in FIG. 1. FIG.
4 is a flowchart showing a processing procedure of processing means in FIG. 1. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 2 ... Rotary kiln, 5 ... Inlet (introduction duct), 6 ... Outlet, 7 ... Heating device, 7a ... Fuel combustion device, 7b ... Combustion air supply nozzle, 14 ... Imaging device, 15 ... Processing means, 16 ... RAM, 17 ... ROM, 20 ... operation control device.

Claims (3)

A device that controls the operation of a rotary kiln that burns and melts the object to be processed by heating with a heating device and discharges it as molten slag from the outlet while the object to be introduced is moved from the inlet side to the outlet while rotating. And
An imaging device for imaging the molten slag flowing down from the outlet;
It is set in advance according to the type of object to be processed (molten slag flows down position) - based on the relationship (information on molten slag temperature), the introduced type and imaged molten slag flow-down position of the object to be processed, Processing means for grasping information on the molten slag temperature and controlling the heating of the heating device based on the information on the grasped molten slag temperature;
Operation control device for rotary kiln equipped with The processing means is preliminarily set in accordance with the type and properties of the object to be processed, based on the relationship of (melted slag flow position)-(information on the molten slag temperature), and the type and characteristics of the introduced object to be processed and The operation of the rotary kiln according to claim 1, wherein information on the molten slag temperature is grasped from the imaged molten slag flow position, and heating of the heating device is controlled based on the grasped information on the molten slag temperature. Control device.   The operation control device for a rotary kiln according to claim 1 or 2, wherein the information on the molten slag temperature is a molten slag temperature or a molten slag viscosity.

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