JP2004251520A - Method of controlling operation of electric melting furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of controlling operation of an electric melting furnace for melting municipal refuse and refuse burned residue permitting efficient, stable, and automatic operation of the electric melting furnace with low running cost. <P>SOLUTION: In this method of controlling operation of the electric melting furnace for melting municipal refuse and refuse burned residue, input power or melted matter supply quantity into the electric melting furnace is set, and the melted matter supply quantity or the input power into the electric melting furnace is calculated on the basis of the respective set values. The melted matter supply quantity and the input power are respectively controlled via a controller such that the input power and the melted matter supply quantity into the electric melting furnace equal to the set value and the calculated value or that the melted matter supply quantity and the input power into the electric melting furnace are the set value and the calculated value. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an operation control method for an electric melting furnace such as an arc melting furnace, a plasma arc melting furnace, or a resistance melting furnace for melting and processing municipal solid waste and incineration residues of municipal solid waste. Calculate the optimum amount of molten material to be processed or input power by setting either of the input powers and control the operation of the electric melting furnace based on these to change the amount of molten material to be processed or its properties. Also, the present invention relates to an operation control method for an electric melting furnace capable of realizing an optimal operation in response to a change in a power supply situation.
[0002]
[Prior art]
BACKGROUND ART Conventionally, electric melting furnaces such as an arc melting furnace, a plasma arc melting furnace, and a resistance melting furnace are often used for melting treatment of municipal waste and incineration residues of municipal waste. This is because electric power for melting is easily obtained from the power generation equipment of the refuse incineration facility, and further reduction of incineration residues and the like and high-quality resource recycling can be achieved.
FIG. 8 shows an example of a known plasma arc melting furnace widely used for melting processing of incinerated ash and the like, and a main electrode 2 and an auxiliary electrode 3 are provided on a ceiling wall of a furnace main body 1 and a furnace. Furnace bottom electrodes 4 are provided on the bottom surface of the main body 1, respectively, and a DC voltage is applied between the main electrode 3 and the furnace bottom electrode 4 from a DC power supply 5 to generate a plasma arc 6 between the main electrode 2 and the molten slag D. The incineration residue C supplied to the inside of the furnace body 1 by the generated heat is sequentially melted. In FIG. 8, B is a molten metal such as a metal, 7 is a current collector, 8 is an inlet for incineration residue C, 9 is a bottleneck for molten slag D, and 10 is an outlet for molten metal B. , 12 is a main electrode support device, 13 is an auxiliary electrode support device, 14 is a power switchboard, and 16 is a device for supplying incineration residue C.
[0003]
The incineration residue C supplied into the furnace body 1 from the charging port 8 by the supply device 16 is sequentially melted by the heat generated by the plasma arc 6 and the heat of the molten slag D, and the molten slag D in the furnace body 1 is melted. Flows down into a cooling water tank (not shown) sequentially through the bottleneck 9 and is collected as water-cooled slag.
Further, the combustion exhaust gas G ₀ that occur is accompanied furnace body 1 for melting the incineration residue C is attracted from隘流port 9, etc. into the furnace body 1 outside, complete combustion of the combustible components in the secondary combustion chamber After that, the exhaust gas is discharged from the chimney to the atmosphere through an exhaust gas cooling device, an exhaust gas treatment device (dust collection device), and an induced draft fan (not shown).
[0004]
Further, during the operation of the electric melting furnace, the operator appropriately selects the input power (input voltage, input current) obtained empirically in advance from the throughput of the incineration residue C and the like, and performs the selection. The continuous operation of the electric melting furnace is achieved by adjusting and controlling the supply amount of the incineration residue C and the input electric power by independent control systems based on the set values thus set.
Since the configuration of the electric melting furnace, the steady melting operation of the incineration residue C, the operation of the exhaust gas treatment device, and the like are known technologies, detailed description thereof will be omitted here.
[Patent Document 1]
JP 2001-50528 A [Patent Document 2]
JP-A-8-121739
[Problems to be solved by the invention]
Electric melting furnaces such as the above-mentioned conventional plasma arc melting furnace, arc melting furnace, and resistance melting furnace can stably melt a material C to be melted such as incineration residues, and have excellent practical utility. is there.
However, there are still many problems to be solved in the conventional melting furnace, and in particular, the operation and operation of the electric melting furnace tend to greatly depend on the operating experience and operating skill of the operator. That is, the operation control of the electric melting furnace is greatly different from each other, which remains as a problem to be solved.
[0006]
Specifically, the amount and properties of the incineration residue C supplied to the electric melting furnace vary depending on the waste incinerator that is the generation source, and vary greatly depending on the season and time.
Further, the cost of the electric power supplied to the electric melting furnace also varies depending on the electric power supply circumstances. For example, nighttime electric power is cheaper than daytime.
Therefore, in order to operate the electric melting furnace more efficiently and economically, it is necessary to comprehensively consider the power supply situation, the required processing amount of the processing object C and its properties, and It is necessary to jointly control the supply amount of C and the input power.
[0007]
However, in the conventional operation control method of the electric melting furnace relatively depending on the operation experience and the operation skill of the operator as described above, fluctuations in the power supply situation and the processing amount and properties of the material C to be melted are considered. However, it is difficult to operate the electric melting furnace efficiently and economically in response to the change in the temperature, and as a result, there is a problem that the melting cost of the object C cannot be significantly reduced.
[0008]
The present invention has the above-mentioned problem in the operation control of an electric melting furnace in which the conventional municipal waste or refuse incineration residue or the like is used as the material to be melted C, that is, the degree of dependence on the operating experience and operating skill of the operator is high. In order to solve the problem that efficient and economical operation of the electric melting furnace cannot be performed quickly in response to changes in the power supply situation, the amount of material to be treated and the properties, Calculate the optimal amount of material to be melted or the input current and input voltage by setting either the input power or the input power, thereby automatically operating the electric melting furnace without depending on the operating experience of the operator. In addition to enabling operation, the reference value of the processing amount of the molten material and the reference setting of the input power can be switched to any one in an arbitrary time unit, so that the power supply situation and the processing amount and the property of the molten material can be changed. Suitable for change Another operation control method time the optimum electric melting furnace for perform operations is to provide.
[0009]
[Means for Solving the Problems]
In the electric melting furnace, the control of the processing amount (supply amount) and the input power (input voltage, input current) of the material to be melted C is a basic control target in the operation control of the electric melting furnace.
Incidentally, the relationship between the input amount (processing amount) of the melt and the input power can be generally represented by the following equation.
Input power = K × [Amount of molten material processed × Specific heat of molten material × (Melting slag temperature of molten material−Initial temperature of molten material) + (Amount of heat released from the melting furnace body)] (1) Here, K is a constant.
That is, as is clear from the relational expression of the above (1), if either the processing amount of the melt C or the input power is determined, the other is calculated in conjunction with this, and as a result Optimum operation control of the electric melting furnace can be realized.
[0010]
In the present invention, in order to realize the above-mentioned optimal operation control of the electric melting furnace, (1) calculating the optimum input electric energy by setting the processing amount of the material to be melted; and (2) By setting the input power, the two types of calculations, that is, calculating the optimum amount of the molten material to be processed, are automatically performed, and one of the above (1) and (2) is operated by the electric melting furnace. It is possible to switch and select as a control base, and to automatically control the supply amount of the material to be melted to the electric melting furnace, the input voltage and the input current based on the selected operation control method (1) or (2). Thereby, stable automatic operation control of the electric melting furnace can be realized.
[0011]
In addition, the present invention makes it possible to switch between the above items (1) and (2) in units of one hour under continuous operation, thereby making it possible to change the power rates during the day and night, the power supply situation, and the properties of the material to be melted depending on the season. It is possible to perform optimal automatic operation control of the electric melting furnace in response to fluctuations and fluctuations in the carry-in amount of the material to be melted.
[0012]
That is, the invention according to claim 1 of the present application relates to an operation control method of an electric melting furnace in which municipal waste or refuse incineration residue is used as a material to be melted. Set and calculate the supply amount or input power of the molten material to the electric melting furnace based on each set value, the input power and the supply amount of the molten material to the electric melting furnace to the set value and the calculated value, Alternatively, the basic structure of the invention is such that the supply amount of the melt and the input power are controlled via a control device such that the supply amount and the input power of the melt to the electric melting furnace are the set value and the calculated value, respectively. Configuration.
[0013]
The invention according to claim 2 is a method for controlling the operation of an electric melting furnace in which a municipal refuse or a refuse incinerator is used as an object to be melted, wherein the operation control of the electric melting furnace is performed by setting power to be supplied to the electric melting furnace. An operation control method for calculating the supply amount of the melt to the electric melting furnace from the set value of the input power, and controlling the input power and the supply amount of the melt based on the set value and the calculated value, The supply amount of the molten material to the electric melting furnace is set, and the power to be supplied to the electric melting furnace is calculated from the set value of the supply amount of the molten material. The basic structure of the present invention is that the operation control method is controlled based on the reference and the configuration is such that the selection is switched at an arbitrary time interval.
[0014]
According to a third aspect of the present invention, in the first or second aspect of the present invention, the molten material or the input electric power is obtained by: input electric power = K × [melt supply amount × specific heat of the molten object × (of the molten object) (The molten slag temperature−the initial temperature of the material to be melted) + (the amount of heat released from the melting furnace body)] (where K is a constant).
[0015]
According to a fourth aspect of the present invention, in the first or second aspect of the invention, the applied power is displayed by an applied voltage and an applied current.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an outline of a plasma arc melting furnace used for carrying out the present invention, and FIG. 2 is an equivalent circuit diagram of an electric system of the electric melting furnace of FIG. The configuration of the plasma arc melting furnace itself is substantially the same as that of the conventional plasma arc melting furnace. Further, in this embodiment, a plasma arc electric melting furnace is used as an electric melting furnace used for carrying out the present invention, but it goes without saying that any type of electric melting furnace may be used as the melting furnace.
[0017]
In FIGS. 1 and 2, A is an electric melting furnace, D is the molten slag, B is molten metal, C is the melt, G ₀ is flue gas, Ra arc resistance, Rm is molten slag resistance, Vp Is a supply voltage, Ip is a supply current, 1 is a furnace body, 2 is a main electrode, 3 is an auxiliary electrode, 4 is a furnace bottom electrode, 5 is a DC power supply, 6 is a plasma arc, 7 is a current collector, and 8 is a target. A melt inlet, 9 is a bottleneck of molten slag D, 10 is an outlet for molten metal, 11 is an exhaust gas outlet, 12 is a main electrode support device, 13 is an auxiliary electrode support device, 14 is a power switchboard, Reference numeral 15 denotes a control device, 16 denotes a device to supply a material to be melted (incinerated ash), and the main electrode 2 is a positive electrode of the DC power supply 5, and the current collecting plate 7 forming the auxiliary electrode 3 and the furnace bottom electrode 4 is a negative electrode. Connected to each other.
[0018]
With reference to FIGS. 1 and 2, a melt C such as incineration ash supplied into the furnace main body 1 through the melt input port 8 by the melt supply device 15 is supplied to the molten slag in the melt furnace main body 1. D, the molten slag D is sequentially melted by the heat of the molten slag D and the heat generated by the plasma arc 6, and the molten slag D flows down into the cooling water tank (not shown) through the bottleneck opening 9, and the granulated slag is discharged. It is formed.
Further, after the combustion exhaust gas G ₀ generated in the melting furnace body 1, which is introduced through the exhaust gas outlet 11 to the secondary combustion chamber by inducing the action of the induced draft fan for the melting furnace, which is here a secondary combustion gas The gas is purified through a cooling device and an exhaust gas treatment device, and is released into the atmosphere (not shown).
[0019]
FIG. 3 is a flow chart of operation control when the method of the present invention is applied to the plasma arc melting furnace shown in FIG. 1, and FIG. 4 is a control block diagram mainly showing a power relation in the operation control. 5 is a control block diagram mainly showing the ash supply relation in the operation control.
3 to refer to FIG. 5, first, when the operation of the electric melting furnace A, checking of mechanical and electrical initial conditions in step S ₀ (e.g., check the main operating conditions of the main electrode supporting device 12 Checking the wear of the electrode 2, checking the operating conditions of the workpiece supply device 16, the supply status of the workpiece C, the operating conditions of the DC power supply 5, the operating conditions of the power distribution board 14, the control device 15, etc.) Done.
[0020]
When establishment of the initial condition is verified, the upper limit setting of the input electric power in step S ₁ (or selection) is performed.
The upper limit value of the inputtable power is set to check for power shortage when power is supplied from the power generation equipment installed in the refuse incinerator, and is usually set to a value equal to or less than the rated power receiving capacity. Is set.
Incidentally, in the case of no upper limit setting, control is directly transferred to the next step S _2. In addition, when the power supplied from the power generation facility falls below the power input set value on the electric melting furnace side due to the power generation situation, the power set value on the electric melting furnace side is automatically adjusted so as not to overload the power generation equipment. It also plays a role in narrowing down the power that can be supplied from the power generation facility.
[0021]
In step S _2, set the operating mode of the electric melting furnace (selection) is performed. That is, three types of operation modes of the electric melting furnace, automatic operation, manual operation, and holding operation, are prepared, and the automatic operation is a so-called fully automatic operation mode of the electric melting furnace to which the present invention is applied.
The manual operation is a manual operation mode in which the operator manually controls the supply of the workpiece C, the applied power (the applied voltage, the applied current), and the like.
Further, the holding operation is an operation mode in which the electric melting furnace is maintained in the current state, and the supply (feeding) of the material to be melted C is stopped, but it corresponds to the heat release amount of the furnace body to the electric melting furnace A. This is an operation mode in which electric power is supplied, the temperature of the molten slag D in the furnace main body is maintained at a predetermined temperature, and the ash can be immediately melted.
[0022]
When the holding operation mode in the step S ₂ is selected, control passes to step SS _1, holding operation control corresponding to a subroutine is initiated.
Similarly, when the manual operation mode is selected in step S _2, control passes to step SS _2, manual control corresponding to a subroutine is initiated. That is, first, the ash supply amount, the input voltage, the input current, and the like are manually set, and the operation control of the electric melting furnace is manually performed based on these set values.
[0023]
When the automatic operation mode is selected at the step S _2, control will be moving to the automatic operation control according to the present invention, the input and switching (selection) Hourly set in step S ₃ is set Is done.
That is, when the time another set in step S ₃ is in the ON (to select the time another set), control passes to step SS _3, as described by the formula 1, the melt processing amount set The operation control of the electric melting furnace based on the input power as the base (main) and the operation control of the electric melting furnace based on the set input power as the base (main) and the supply amount of the melted material are prescribed. The switching is performed in units of time.
Specifically, “plasma control by time setting” corresponding to a subroutine is performed, setting of input power by time setting and setting of ash supply amount by time setting are performed, and melting based on these is performed. An amount of supplied material and input power are calculated, and operation control of the electric melting furnace is performed based on the set values and the calculated values.
[0024]
Step S ₃ in Hourly control setting is set to OFF (no separate control time) (selected), the control proceeds to step 4, selecting and setting of the automatic operation is performed.
That is, the operation control is performed based on the supply amount of the melted material C in Equation 1 as a base (main) and the control of the input power is dependent, or the supply amount of the melted material based on the input power as the base (main). Any one of the operation control methods is selected to determine whether or not the above operation control is the operation control.
[0025]
In Step S _4, the control based upon the object to be treated supply amount (ash supply amount) is selected, setting of the melt supply amount (ash supply amount) (Step S ₅₎ is performed, set charged voltage commensurate with the melt feed amount that is, calculation of the current (power) is performed in step S _6.
[0026]
When the control based on the input power is selected in step 4, the input power is set in step 7, and the supply amount of the molten material (the ash supply amount) corresponding to the set input power is calculated in step 8. Is done.
[0027]
When the required input power or the possible supply amount of the molten material is calculated in step 6 or step 8, the DC power supply device 5 and the main electrode support device are operated so that the supplied power or the supply amount of the molten material is secured. It goes without saying that the elevation and the like of 9 and the operation and the like of the molten material supply device 16 are respectively controlled via the control device 15.
[0028]
In addition, the calculation of the required input power when the supply amount of the melt is based on the above (Equation 1) and the calculation itself of the possible input amount of the melt when the supply power is the base (main) are as follows. It is known. Therefore, although a detailed description of these is omitted here, a plasma arc melting furnace (capacity of DC power supply unit: 600 to 1000 kWH / ash T, voltage: 100 to 550 V) using incinerated ash such as municipal waste as a material to be melted C In the case of), assuming that the supply amount of the melt is 4.0 T / Hr, the input power is about 2700 (current 9000 A, voltage 300 V) from KVA to 3000 KVA, and the input power is 2725 (current 9083 A, voltage 300 V). ) Assuming KVA, the supply amount of the melted material is between about 3.6 T / Hr and 4.4 T / Hr.
[0029]
FIG. 6 shows a list of control objects in the operation control method of the electric melting furnace according to the present invention. Items described in a frame surrounded by a double line are to be controlled, and numerical values indicated by XX represent set values or calculated values.
[0030]
Figure 7 is a table showing a control situation when carrying out the hourly operating control method for an electro-melting furnace according to the present invention, using the control in step SS ₃ in FIG. 3, time 0 the input power basis, Operation control is performed between 4 to 7, 8, 12 to 16, and 20 to 23, and operation control is performed during times 1 to 3, 9 to 11, and 17 to 19 on the basis of the supply amount of the material to be treated (ash supply amount). Are respectively shown. In addition, xx in a frame shows each numerical value.
[0031]
【The invention's effect】
In the invention of claim 1 of the present application, at the time of operation control of an electric melting furnace that uses municipal waste and refuse incineration residue as a material to be melted, firstly, an electric power supplied to the electric melting furnace or a supply amount of the material to be melted is set, Calculate the supply amount or required input power of the meltable material that can be supplied to the electric melting furnace based on the set values, and the input power and the melt supply amount to the electric melting furnace are set to the set value and the calculated value. Alternatively, the supply amount of the melt and the input power are controlled via the control device such that the supply amount of the melt and the input power to the electric melting furnace become the set value and the calculated value, respectively.
As a result, as in the case of the conventional operation control of this type of electric melting furnace, the operator sets the input power to the electric melting furnace and the supply amount of the melted material based on their experience or skill, or appropriately. There is no need to adjust and control the electric melting, so that it is possible to perform unified control in a so-called fully automatic manner and in a state where the electric power supplied to the electric melting furnace and the supply amount of the material to be melted are linked. The furnace can always be operated with high efficiency and in a stable state.
[0032]
According to the invention of claim 2 of the present application, in the operation control of the electric melting furnace, the operation control of the electric melting furnace is performed by setting the input power to the electric melting furnace and changing the setting value of the input power to the electric melting furnace. An operation control method for calculating the supply amount of the melt to be supplied, and controlling the input power and the melt supply amount based on the set value and the calculated value; and supplying the melt to the electric melting furnace. The amount to be set and the input power to the electric melting furnace were calculated from the set value of the supply amount of the melt, and the supply amount and the input power of the melt were controlled based on the set value and the calculated value. In the operation control method, the selection is switched at an arbitrary time interval.
As a result, according to the invention of claim 3 of the present application, the two operation control methods are performed in accordance with the situation of power supply to the electric melting furnace, the amount of the material to be melted supplied to the electric melting furnace, and the properties thereof. Any of the optimal methods can be arbitrarily selected, and not only the operation efficiency can be improved by completely automating the operation control of the electric melting furnace, but also the running cost of the electric melting furnace can be significantly reduced.
As described above, the present invention has excellent practical utility.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view showing the overall configuration of an electric melting furnace (plasma arc melting furnace) used for carrying out the present invention.
FIG. 2 is an electric equivalent circuit of the electric melting furnace of FIG.
FIG. 3 is a flowchart showing operation control of the electric melting furnace of the present invention.
FIG. 4 is a control block diagram mainly related to electric power in operation control of the electric melting furnace.
FIG. 5 is a control block diagram mainly related to ash supply in operation control of the electric melting furnace.
FIG. 6 shows a list of objects to be controlled in the operation control method of the electric melting furnace of the present invention.
FIG. 7 shows a list of control statuses of the electric melting furnace operation control method according to time according to the present invention.
FIG. 8 is a schematic sectional view of a conventional plasma arc electric melting furnace.
[Explanation of symbols]
A electric melting furnace, D is the molten slag, B is molten metal, C is the melt, _{G 0} is flue gas, Ra arc resistance, Rm is molten slag resistance, Vp is charged voltage, Ip is making current, 1 Is a furnace main body, 2 is a main electrode, 3 is an auxiliary electrode, 4 is a furnace bottom electrode, 5 is a DC power supply, 6 is a plasma arc, 7 is a current collector, 8 is an inlet for a material to be melted, and 9 is a molten slag D. 10 is a discharge hole for molten metal, 11 is an exhaust gas outlet, 12 is a main electrode support device, 13 is an auxiliary electrode support device, 14 is a power distribution board, 15 is a control device, and 16 is a material to be melted. Supply device, S _{1 to} S ₈ are control steps, and SS _{1 to} SS ₃ are control steps in sub-control.

Claims (4)

In an operation control method of an electric melting furnace using municipal solid waste and refuse incineration residue as a material to be melted, first, an electric power supplied to the electric melting furnace or a supply amount of the material to be melted is set, and the electric power is set based on the set values. Calculate the supply amount or input power of the melt to the melting furnace, the input power and supply amount of the melt to the electric melting furnace to the set value and the calculated value, or the supply amount of the melt to the electric melting furnace and An operation control method for an electric melting furnace, wherein a supply amount of a material to be melted and an input power are respectively controlled via a control device such that the input power becomes the set value and the calculated value. In the operation control method of the electric melting furnace using the municipal solid waste and the refuse incinerator as the material to be melted, the operation control of the electric melting furnace is performed by setting the input power to the electric melting furnace and from the set value of the input power. An operation control method of calculating the supply amount of the material to be melted to the electric melting furnace, and controlling the input power and the supply amount of the material to be melted based on the set value and the calculated value; and The supply amount to the electric melting furnace is calculated from the set value of the supply amount of the melt and the set value of the supply amount of the melt, and the supply amount and the supply power of the melt are controlled based on the set value and the calculated value. And an operation control method for an electric melting furnace, wherein selection switching is performed at an arbitrary time interval. The power to be melted or the input power is calculated by the following equation: Input power = K × [Material supply amount × Specific heat of the melt target × (Melting slag temperature of the melt target−Initial temperature of the melt target) + (Amount of heat released from the melting furnace body) 3) The operation control method for an electric melting furnace according to claim 1 or 2, wherein the operation is calculated from a relational expression (where K is a constant). The operation control method for an electric melting furnace according to claim 1 or 2, wherein the input power is displayed by the input voltage and the input current.

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