JP6660065B2 - Power control device and method for electric precipitator - Google Patents

Description

  The present invention relates to a power supply control device and method for an electric precipitator for removing dust and the like from waste gas. In particular, the present invention relates to a power supply control device and method for a wet-type electric precipitator that can save power while maintaining the dust collection efficiency of dust containing heavy metals.

  BACKGROUND ART Conventionally, wet electric dust collectors (for example, see Patent Documents 1 to 3) remove harmful dust and mist from waste gas generated not only in sulfuric acid mist treatment and aluminum smelting exhaust gas treatment in the mining industry, but also in waste incineration processes and the like. Used for collection purposes. As described above, the wet electrostatic precipitator has been widely used as a useful device from the viewpoint of air pollution prevention and environmental protection.

  The waste gas to be treated by the wet type electrostatic precipitator contains harmful substances such as lead, cadmium and arsenic and heavy metals. For this reason, in such a wet electric dust collector, it is required to improve the dust collection efficiency of dust containing harmful substances and heavy metals.

The wet-type electrostatic precipitator generally has a dust collecting electrode having a smooth surface formed of two flat plates or a cylindrical shape such as a cylindrical shape or a rectangular cylindrical shape, and a linear type provided in the dust collecting electrode. And discharge lines of the same.
When fine particles such as dust and mist are removed by such a wet electric dust collector, a high voltage is charged between the discharge electrode side and the grounded dust collection electrode side. As a result, a strong current electric field is formed between the discharge electrode side and the grounded collection electrode side, and a strong corona discharge is generated from the discharge electrode side as the voltage increases, and the discharge electrode and the collection electrode side are separated. Is filled with negative ions and electrons. When the exhaust gas is introduced into the dust collecting space, dust and mist in the exhaust gas are negatively charged, move toward the dust collecting electrode due to Coulomb force with electrostatic coagulation, and adhere to the dust collecting electrode. The attached dust or mist loses a negative charge at the dust collecting electrode, is separated from the dust collecting electrode by the washing water supplied to the dust collecting electrode and its own weight, falls, and is discharged to the outside of the electric dust collecting device.
In this way, the wet type electrostatic precipitator can collect various kinds of fine particles such as solid and liquid fine particles with high dust collection efficiency.

  In such a wet-type electrostatic precipitator, there is known a method of increasing a charging voltage between a discharge electrode and a precipitating electrode in order to increase the dust collection efficiency of dust containing heavy metals.

JP 2007-196159 A JP 2002-119889 A Japanese Patent Publication No. Hei 6-91965

  However, simply increasing the charging voltage between the discharge electrode and the dust collection electrode of the wet-type electrostatic precipitator can improve dust collection efficiency, but is extremely uneconomical in terms of power saving. On the other hand, if the charging voltage is simply reduced, the dust collection efficiency of the dust and the like is reduced, so that the dust and the like cannot be sufficiently removed from the waste gas.

  The present invention has been made in view of such circumstances, and has as its object to save power while maintaining the dust collection efficiency of heavy metal-containing dust.

The power supply control device for the electric precipitator according to one aspect of the present invention includes:
A discharge electrode to which a DC high voltage is applied,
By a negative corona discharge generated between the discharge electrode based on the DC high voltage, a dust collection electrode for collecting fine particles contained in exhaust gas discharged from an exhaust gas generation source,
A power control device for an electrostatic precipitator comprising:
A DC high voltage control unit that receives a predetermined control signal related to the exhaust gas generation source and variably controls a DC high voltage applied to the discharge electrode according to the control signal,
It is characterized by having.

  In this case, the predetermined control signal may be an operation control signal for controlling operation and stop of the exhaust gas generation source.

  Further, the predetermined control signal may be information on a raw material flow rate with respect to the exhaust gas generation source.

Further, a power supply control method for an electric precipitator according to one aspect of the present invention,
A discharge electrode to which a DC high voltage is applied,
By a negative corona discharge generated between the discharge electrode based on the DC high voltage, a dust collection electrode for collecting fine particles contained in exhaust gas discharged from an exhaust gas generation source,
A power control method for an electrostatic precipitator comprising:
Receiving a predetermined control signal related to the exhaust gas generation source, and variably controlling a DC high voltage applied to the discharge electrode according to the control signal;
It is characterized by including.

In this case, the method further includes a step of intermittently applying the DC high voltage to the discharge electrode, and executing a control to vary an intermittent interval according to a predetermined control signal regarding the exhaust gas generation source.
Can be included.

  ADVANTAGE OF THE INVENTION According to this invention, while maintaining the dust collection efficiency of the dust containing a heavy metal, the wet-type electric dust collector which can aim at power saving can be implement | achieved.

It is a figure showing the example of composition of the dust collection system concerning a 1st embodiment of the present invention. It is a sectional view showing the schematic structure of the wet type electric precipitator concerning a 1st embodiment of the present invention. It is a perspective view which shows schematic structure inside the housing of a wet-type electrostatic precipitator. It is a figure explaining the space charge effect by the fine particles which exist in the gas inputted into each "chamber" of the collection electrode of the electric precipitator. It is a figure which shows the relationship between the electric current of an electric precipitator and the voltage (DC high voltage V1) at the time of air loading and gas loading. FIG. 6 is a diagram illustrating a specific example of variable control of a charging voltage by a DC high voltage control unit. FIG. 4 is a diagram illustrating a state transition of the power supply control device. It is a figure showing the example of a display of the input screen of TP. It is a figure which shows the time transition of the electric current and voltage of the conventional wet type electrostatic precipitator in actual operation. It is a figure which shows the time transition of the current and the voltage of the wet type electrostatic precipitator according to the first embodiment of FIG. 2 in an actual operation. It is a figure showing the example of composition of the plant to which the dust collection system of a 2nd embodiment of the present invention is applied. It is a figure showing the example of composition of the dust collection system concerning a 2nd embodiment of the present invention. It is a timing chart which concerns on 3rd Embodiment of this invention about the control of switching of the driving | running state by the dust collection system of FIG. A wet type electrostatic precipitator 1 including a conventional product (fixed voltage control), the DC high voltage control unit 42 of the first embodiment in FIG. 1, and a wet type including the DC high voltage control unit 42 in the third embodiment of FIG. It is the figure which compared the energy saving shift trigger, the energy saving method, and the electric power in each of the electric precipitators.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.

[Configuration of dust collection system]
FIG. 1 is a diagram illustrating a configuration example of a dust collection system according to a first embodiment of the present invention.

The dust collection system S shown in FIG. 1 includes a wet electric dust collection device 1, a power supply device 2, and a power supply control device 3, and is connected to an external system 4.
Hereinafter, each configuration of the wet-type electrostatic precipitator 1, the power supply device 2, and the power supply control device 3 will be individually described in that order.

[Configuration of wet electric precipitator]
First, the configuration of the wet-type electrostatic precipitator 1 will be described with reference to FIG.
FIG. 2 is a cross-sectional view illustrating a schematic configuration of the wet electrostatic precipitator according to the first embodiment of the present invention.
Specifically, FIGS. 2A and 2B are cross-sectional views showing a schematic configuration of an external appearance of the wet-type electrostatic precipitator, and are cross-sectional views viewed from different directions substantially perpendicular to each other.

  The wet electric dust collector 1 is provided with an upper casing 11, a dust collecting electrode 12, which also functions as a side casing, a lower casing 13, and a frame 14.

  By combining the upper casing 11, the dust collecting electrode 12, and the lower casing 13 in this order from above, a casing of the wet-type electric dust collector 1 is configured. The housing of the wet electrostatic precipitator 1 is fixed by a frame 14 at a predetermined distance above the ground. In the present embodiment, a conductive FRP (Fiber Reinforced Plastics) is adopted as a material of a housing of the wet-type electrostatic precipitator 1.

FIG. 3 is a perspective view showing a schematic configuration inside the housing of the wet type electrostatic precipitator 1.
As shown in FIG. 3, an upper grid 21, the above-described dust collection electrode 12, a lower grid 23, an electrode rod 24, a discharge wire 25, and a weight 26 are provided inside a housing of the wet-type electrostatic precipitator 1. , An upward spray nozzle 27 and a cleaning pipe 28 are provided.

  As shown in FIG. 3, the upper grid 21, the dust collecting electrode 12, and the lower grid 23 are separated from each other by a predetermined distance in this order from above, and are substantially parallel to each other in the horizontal direction. It is arranged.

As shown in FIG. 3, the dust collection electrode 12 is configured by repeatedly arranging a plurality of “chambers” with a rectangular cylinder as a unit (hereinafter, such a unit is referred to as a “chamber”). .
Specifically, hereinafter, of the substantially horizontal directions, one direction is referred to as a “vertical direction”, and a direction perpendicular to the vertical direction is referred to as a “horizontal direction”. In this case, the dust collecting electrode is formed by repeatedly and continuously arranging N units in the vertical direction and repeatedly and continuously arranging M units in the horizontal direction (hereinafter, referred to as “N × M”). 12 are configured.
Here, N and M are independent arbitrary integer values, and in the present embodiment, as shown in FIG. 3, the number of “chambers” of the dust collection electrode 12 is N × M = 9 × 9. ing.
In addition, the chamber of the present embodiment is a square tube having sides with a length of 35 to 50 cm.
In this embodiment, the material of the dust collecting electrode 12 is a conductive FRP.

In the present embodiment, such a discharge electrode for the dust collection electrode 12 is configured by an electrode rod 24 and a discharge wire 25.
As shown in FIG. 3, the electrode rod 24 is disposed so as to penetrate the center of a predetermined “chamber” of the dust collection electrode 12 in a substantially vertical direction, the upper end is fixed to the upper grid 21, and the lower end is Are fixed to the lower grid 23.
As shown in FIG. 3, the discharge wire 25 is suspended from the upper grid 21 and is disposed so as to penetrate substantially vertically through the center of a predetermined “chamber” of the dust collection electrode 12. The discharge wire 25 is also connected to a weight 26 provided on the upper part of the lower grid 23 so as to have a tension that does not loosen.

  A negative DC high voltage (charge voltage) supplied from the power supply device 2 is directly applied to the electrode rod 24. On the other hand, the DC high voltage of the negative electrode is applied to the discharge line 25 via the upper grid 21.

  The upward spray nozzles 27 are disposed above the four corners of each “chamber” of the dust collection electrode 12, and eject the cleaning water flowing through the cleaning pipe 28 as fine mist in a substantially vertical upward direction. This makes it possible to wash and remove fine particles such as mist and dust attached to the dust collection electrode 12.

In the wet type electrostatic precipitator 1 of the present embodiment, the cleaning water is ejected from the upward spray nozzle 27 in a substantially vertical upward direction as fine mist. Thereby, the dispersion of the washing water is improved, so that the amount of the washing water to be used can be made smaller than that of the conventionally used water.
The upward spray nozzle 27 is a component that contributes to an increase in the negative DC high voltage applied to the electrode rod 24 and the discharge wire 25.

  Next, with reference to FIG. 1 again, the configuration of the power supply device 2 for applying the negative DC high voltage V to the electrode rod 24 of such a wet type electrostatic precipitator 1 will be described.

  As shown in FIG. 1, the power supply device 2 generates a negative DC high voltage V in accordance with a voltage set value supplied from a power supply control device 3 described later, and supplies the negative electrode DC high voltage Apply. The current values of the voltage and the current of the wet-type electrostatic precipitator 1 are fed back to the power supply controller 3 and are appropriately used for control described later.

On the panel of the power supply device 2, a changeover switch 31, a volume 32, and a display unit 33 are provided in this order from the bottom.
The changeover switch 31 is a switch that switches the control of the power supply device 2 from one of “distant” and “direct” to the other. When the changeover switch 31 is switched to “far”, the power supply device 2 is remotely controlled by a power supply control device 3 described later. On the other hand, when the changeover switch 31 is switched to “direct”, the power supply device 2 is controlled by a direct operation of the panel by a nearby operator (not shown).
The volume 32 is operated by the operator when the changeover switch 31 is switched to “direct”, and gives an instruction to change the voltage set value or the current set value. That is, when the changeover switch 31 is switched to “far”, the operation of the volume 32 is prohibited.
The display unit 33 displays the current values of the voltage and the current of the wet type electrostatic precipitator 1.

  Next, the configuration of the power supply control device 3 for controlling the power supply device 2 will be described with reference to FIG.

  The power supply control device 3 is configured by, for example, a programmable logic controller (PLC), and includes a touch panel (TP) 41 and a DC high voltage control unit 42.

  The TP 41 is stacked on a display screen that displays various information, and inputs various information according to a user's instruction operation. The details of the input screen of the TP 41 will be described later with reference to FIG.

The DC high-voltage control unit 42 determines the value of the charging voltage from the power supply device 2 according to the concentration of fine particles (dust, dust, etc.) contained in the gas (gas G1 in FIG. 2) input to the wet-type electrostatic precipitator 1. Is variably controlled.
The DC high voltage control unit 42 functionally includes a concentration determination unit 51 in order to variably control the charging voltage according to the concentration of such fine particles.
Here, the reason why the function is described is that there is no need to limit the implementation form of the density determination unit 51 to hardware. That is, the density determination unit 51 only needs to have the following functions, and its realization form is not particularly limited, and may be configured by hardware, may be configured by software, or a combination thereof. May be configured.

The concentration determining section 51 has a function of determining the concentration of the fine particles. The mode of realizing the function is not particularly limited, and may be a function of actually measuring the concentration of the fine particles. In the present embodiment, however, a current electric field formed between the discharge electrode side and the grounded dust collection electrode 12 side is used. The function of estimating the concentration of the fine particles by detecting the current of the corona discharge caused by the above is provided in the concentration determination section 51. In other words, the function of detecting the current as an index of the concentration of the fine particles is provided in the concentration determination unit 51.
Hereinafter, with reference to FIGS. 4 to 7, details of a function provided in the concentration determination unit 51, that is, a function of detecting a current as an index of the concentration of fine particles will be described.

FIG. 4 is a diagram illustrating the space charge effect due to the fine particles present in the gas input to each “chamber” of the dust collection electrode 12 of the wet type electrostatic precipitator 1.
Hereinafter, a state in which the gas input to each “chamber” of the dust collecting electrode 12 of the wet type electrostatic precipitator 1 contains almost no fine particles such as dust and dust (dust collection target) is referred to as “air load”. The state in which fine particles such as dust and dust (dust collection target) are contained in a certain amount or more is called “gas load”.
As shown in FIG. 4A, when air is loaded, a DC high voltage is applied between the electrode rod 24 or the discharge wire 25 (hereinafter, only the discharge wire 25 is referred to for convenience of description) and the grounded dust collection electrode 12. When the voltage V is applied, a strong current electric field is formed between the discharge wire 25 side and the grounded dust collection electrode 12 side, and vigorous corona discharge is generated from the discharge wire 25 side as the voltage increases. I do.
On the other hand, as shown in FIG. 4B, the concentration of fine particles such as dust in the gas (the gas G1 in FIG. 2) input to the opening of each “chamber” of the dust collection electrode 12 at the time of gas loading. Is higher, the fine particles are charged, and a large amount of space charges (negative ions i) are formed in the dust collection space in the “chamber”. Then, the corona discharge near the discharge line 25 is suppressed by the shielding effect of these large amounts of space charges. Suppression of corona discharge by such a large amount of space charge is generally called “space charge effect” or “corona blocking phenomenon”. The space charge effect (corona blocking phenomenon) is more likely to occur as the concentration of fine particles such as dust in the gas G1 (gas) increases and as the particle diameter of the fine particles decreases.

Next, the relationship between the current and the voltage of the wet electrostatic precipitator 1, which changes according to the concentration of the fine particles, will be described with reference to FIG.
FIG. 5 is a diagram showing the relationship between the current and the voltage (DC high voltage V1) of the wet type electrostatic precipitator 1 during air loading and gas loading.
Specifically, a curve L1 indicating a relationship between a current and a voltage during air loading and a curve L2 indicating a relationship between a current and a voltage (high DC voltage V1) during gas loading are shown.
In FIG. 5, the vertical axis indicates the current of the wet type electrostatic precipitator 1, and the horizontal axis indicates the effective voltage of the charging voltage (DC high voltage V1) of the wet type electrostatic precipitator 1.
When the DC high voltage of the wet electrostatic precipitator 1 is a constant value V1a (V1a is an arbitrary value equal to or less than the rated voltage), the curve L2 at the time of gas loading with a high concentration of fine particles is better than the concentration of fine particles. Are lower than the curve L1 at the time of low air load. Thus, when the DC high voltage of the wet type electrostatic precipitator 1 is the constant value V1a, the concentration of the fine particles decreases as the current value increases, and conversely, increases as the current value decreases. I understand.
Therefore, in this embodiment, as described above, the current is detected as an index of the concentration of the fine particles, and the value of the DC high voltage V1 is variably controlled according to the value of the detected current.

More specifically, as can be seen from the curve L2 at the time of gas loading, the higher the concentration of fine particles in the gas G1 (gas), the lower the current value of the wet electrostatic precipitator 1 due to the space charge effect. Therefore, when the current value of the wet electrostatic precipitator 1 (current value of the current supplied from the power supply device 2) is low, the concentration determination unit 51 determines the concentration of the fine particles such as dust in the gas G1 (gas). Is high.
On the other hand, as can be seen from the curve L1 at the time of air loading, the lower the concentration of the particles in the gas G1 (gas), the higher the current value of the wet electrostatic precipitator 1 due to the space charge effect. Therefore, when the current value of the wet electrostatic precipitator 1 (current value of the current supplied from the power supply device 2) is high, the concentration determination unit 51 determines the concentration of the fine particles such as dust in the gas G1 (gas). Is low.

  Next, a specific example of the variable control of the charging voltage by the DC high voltage control unit 42 applied to the present embodiment will be described with reference to FIG.

FIG. 6 is a diagram illustrating a specific example of the variable control of the charging voltage by the DC high voltage control unit 42.
FIG. 6 shows a curve L3 indicating the relationship between the current and the voltage during air loading, and a curve L4 indicating the relationship between the current and the voltage (high DC voltage V1) during the gas loading.
6, the vertical axis indicates the current of the wet type electrostatic precipitator 1, and the horizontal axis indicates the effective voltage of the charging voltage (DC high voltage V1) of the wet type electrostatic precipitator 1.
In the present embodiment, the effective voltage of the charging voltage (DC high voltage V1) of the wet type electrostatic precipitator 1 assumes two values: an energy saving voltage value V12 and a normal voltage value V11 (V11> V12).
Here, in the present embodiment, in order to realize such variable control shown in FIG. 6, as shown in FIG. 1, the density determining unit 51 includes a density increasing determining unit 61 and a density decreasing determining unit 62. Prepare.
When the current value (the current value of the current supplied from the power supply device 2) becomes equal to or less than the first threshold value C1 (see FIG. 6), the concentration increase determination unit 61 determines that the concentration of the fine particles has increased. . When the current is equal to or less than the first threshold value C1, the concentration of the fine particles becomes higher than a certain value, so that the dust collection efficiency of the fine particles needs to be increased. Therefore, when the current becomes equal to or less than the first threshold value C1, the DC high-voltage control unit 42 increases the charging voltage (DC high voltage V1) of the power supply device 2 from the energy-saving voltage value V12 to the normal voltage value V11. Dust collection efficiency is improved by performing control, more specifically, control to increase the voltage set value.
On the other hand, when the current value (current value of the current supplied from the power supply device 2) becomes equal to or more than the second threshold value C2, the concentration decrease determination unit 62 determines that the concentration of the fine particles has decreased. When the current is equal to or higher than the second threshold value C2, the concentration of the fine particles is low, and it is not necessary to increase the dust collection efficiency of the fine particles. Therefore, when the current becomes equal to or more than the second threshold value C2, the DC high voltage control unit 42 lowers the charging voltage (DC high voltage V1) of the power supply device 2 from the normal voltage value V11 to the energy saving voltage value V12. By controlling, power saving is achieved.

As described above, when the current value becomes equal to or less than the first threshold value C1 and the concentration of the fine particles becomes higher than a certain value, the charging voltage (the DC high voltage V1) of the power supply device 2 becomes the normal voltage value V11 and the collection of the fine particles Dust efficiency is improved.
Here, although the current value is equal to or higher than the second threshold value C2 and the concentration of fine particles is reduced, the charging voltage (DC high voltage V1) of the power supply device 2 is excessive if the normal voltage value V11 is maintained. This means that a high charging voltage is applied, and power is wasted. Therefore, in such a case, the charging voltage (DC high voltage V1) of the power supply device 2 is reduced to the energy saving voltage value V12, and power saving can be achieved.

The power supply device 2 prevents the occurrence of spark discharge by reducing the value of the DC high voltage V1 for a short time during abnormal discharge.
However, a decrease in the value of the DC high voltage V1 during abnormal discharge causes a decrease in the current value. Therefore, regardless of the concentration of the fine particles (even when the concentration of the fine particles does not change), even if the abnormal discharge occurs and the value of the DC high voltage V1 decreases, If the current value is equal to or less than the first threshold value C1, there is a possibility that the concentration of the fine particles is erroneously determined to have increased.
Therefore, in order to prevent such an erroneous determination, the concentration determination unit 51 prohibits the detection of a change in the concentration of the fine particles while the value of the DC high voltage V1 is reduced due to the abnormal discharge.

[Operation of wet electric precipitator]
Next, the operation of the dust collection system S of the present embodiment having the above configuration will be described with reference to FIG.
FIG. 7 is a diagram illustrating a state transition of the power supply control device.
In FIG. 7, each state is indicated by one ellipse, and is determined by a code including “S” drawn on the ellipse.
The state transition from one state to one state is executed when a predetermined condition (hereinafter, referred to as “transition condition”) is satisfied.
In FIG. 7, such a transition condition is represented by an arrow representing a transition from one state to one state, with a sign including “T” attached.

Hereinafter, each of the states S1 to S3 will be described.
The standby state S1 is an initial state in which the power of the power supply control device 3 is turned on, and is a state in which the charging voltage (voltage set value) is still in a standby state with 0V.
In the normal voltage state S2, when the concentration of fine particles in the gas G1 (gas) is high, the charging voltage (voltage setting value) is set to the normal voltage value V11 in order to increase dust collection efficiency and remove these fine particles. It is in a state where it is.
The energy saving voltage state S3 is a state in which the charging voltage (voltage setting value) is set to the energy saving voltage value V12 in order to suppress the amount of power consumed when the concentration of the fine particles in the gas G1 (gas) becomes low. is there. The energy saving voltage value V12 is defined as a value that allows the concentration of impurities such as fine particles to be equal to or lower than a target value even if the dust collection efficiency of fine particles is reduced.

  Hereinafter, transition conditions T1 to T5 for transitioning to each of the states S1 to S3 will be described.

  Transition condition T1: a condition for transition from the standby state S1 to the normal voltage state S2. In the standby state S1, when a switch (not shown) for instructing the start of dust collection is turned on or an external system 4 is satisfied when the activation signal transmitted from 4 is received.

  Transition condition T2: a condition for transitioning from the normal voltage state S2 to the energy saving voltage state S3, and is satisfied when the current value of the current becomes equal to or more than the second threshold value C2 (see FIG. 6) in the normal voltage state S2. It is.

  Transition condition T3: a condition for transitioning from the energy saving voltage state S3 to the normal voltage state S2, and is satisfied when the current value of the current becomes equal to or less than the first threshold value C1 (see FIG. 6) in the energy saving voltage state S3. It is.

  Transition condition T4: a condition for transition from the normal voltage state S2 to the standby state S1. In the normal voltage state S2, when a switch (not shown) for instructing the start of dust collection is turned off or external. The condition is satisfied when the stop signal transmitted from the system 4 is received.

  Transition condition T5: a condition for transitioning from the energy saving voltage state S3 to the standby state S1, and in the energy saving voltage state S3, when a switch (not shown) for instructing the start of dust collection is turned off or externally. The condition is satisfied when the stop signal transmitted from the system 4 is received.

  Here, the external system 4 is a system that controls the entire process involving generation of exhaust gas, and exchanges various information with the power supply control device 3 by communication. For example, the external system 4 transmits a start signal of the dust collection system S to the power supply control device 41 when a predetermined condition is satisfied.

In the standby state S1, when such an activation signal transmitted from the external system 4 is received, or when a switch (not shown) for instructing the start of dust collection is turned on, the transition condition T1 becomes When satisfied, the state of the power supply control device transitions from the standby state S1 to the normal voltage state S2.
Then, the DC high-voltage control unit 42 sets the normal voltage value V11 to the voltage set value and notifies the power supply device 2 of the same. Although the form of the notification is not particularly limited, the present embodiment employs a method of notifying the voltage set value by transmitting a level signal that varies between 4 and 20 mA according to the voltage set value. That is, a voltage value is associated in the range of 4 to 20 mA, and a voltage value corresponding to the level (current value) of the level signal is notified from the DC high voltage control unit 42 to the power supply device 2 as a voltage set value.
The power supply device 2 generates the DC high voltage V1 so as to have the notified voltage set value, that is, the normal voltage value V11 here, and applies the DC high voltage V1 to the wet electric precipitator 1.

While the normal voltage state S2 continues, the exhaust gas stops due to the stop of the process controlled by the external system 4 and the concentration of the fine particles in the gas G1 (gas) decreases. When the current value of the current notified from the power supply device 2 increases and becomes equal to or more than the second threshold value C2, the transition condition T2 is satisfied, and the state of the power supply control device 3 changes from the normal voltage state S2 to the energy saving voltage state S3. Transition.
Then, the DC high-voltage control unit 42 sets the energy saving voltage value V <b> 12 to the voltage set value (updates the setting), and notifies the power supply device 2. The power supply device 2 generates the DC high voltage V1 so as to have the notified voltage set value, that is, the energy saving voltage value V12 here, that is, reduces the DC high voltage V1 and applies it to the wet-type electrostatic precipitator 1. .

While the energy saving voltage state S3 continues, the concentration of the fine particles in the gas G1 (gas) increases due to the re-generation of the exhaust gas due to the restart of the process controlled by the external system 4 or the like. Accordingly, when the current value of the current notified from the power supply device 2 decreases and becomes equal to or less than the first threshold value C1, the transition condition T3 is satisfied, and the state of the power supply control device 3 changes from the energy saving voltage state S3 to the normal voltage state S2. Transitions to.
Then, the DC high-voltage control unit 42 sets the normal voltage value V <b> 11 to the voltage set value (updates the setting), and notifies the power supply device 2. The power supply device 2 generates the DC high voltage V1 so as to have the notified voltage set value, that is, the normal voltage value V11, that is, raises the DC high voltage V1 and applies the DC high voltage V1 to the wet-type electrostatic precipitator 1. .

  In the normal voltage state S2 or the energy saving voltage state S3, if a switch (not shown) for instructing the start of dust collection is turned off, or a stop signal transmitted from the external system 4 is received. In this case, the transition condition T4 or T5 is satisfied, and the state of the power supply control device 3 transits from the normal voltage state S2 or the energy saving voltage state S3 to the standby state S1.

[Display example of TP]
Next, a display example of the input screen of the TP 41 of the power supply control device 3 of the present embodiment having the above configuration will be described.
FIG. 8 is a diagram illustrating a display example of a TP input screen.

The control state of the power supply device 2 is displayed in the upper left column of TP41. That is, the display in the upper left column corresponds to the state of the switch 31 on the board of the power supply device 2.
In the upper right column of TP41, the current values of the voltage and the current notified from the power supply device 2 are displayed. In the example shown in the figure, “50” kv is displayed as the current value of the voltage, and “700” mA is displayed as the current value of the current. That is, the display in the upper right column corresponds to the state of the display unit 33 on the board of the power supply device 2.

The set values of the normal voltage state S2 and the energy saving voltage state S3 are displayed in the middle column of TP41.
In the example shown in the figure, “60” kv is used as the charging voltage in the normal voltage state S2, “900” mA is used as the second threshold value C2, and “0” minutes is used as the remaining time of the normal voltage state S2. “3” minutes are set as the duration setting value of the voltage state S2.
In addition, “50” kv as the charging voltage in the energy saving voltage state S3, “600” mA as the first threshold value C1, “0” minutes as the remaining time of the energy saving voltage state S3, and continuation of the energy saving voltage state S3 "1" minute is set as the time setting value.

  Here, referring to FIGS. 9 and 10, the variable control of the charging voltage (FIG. 10) by the DC high voltage control unit 42 applied to the present embodiment is compared with the conventional charging voltage control (FIG. 9). The advantage will be described.

FIG. 9 is a diagram showing a temporal transition of a current and a voltage (DC high voltage V1) of the conventional wet type electrostatic precipitator in an actual operation.
Specifically, a curve L5 indicating a current and a curve L6 indicating a voltage (DC high voltage V1) during predetermined times t1 to t5 are shown.
In FIG. 9, the vertical axis indicates the effective voltage (kV) or the current (mA) of the charging voltage (DC high voltage V1) of the wet type electrostatic precipitator, and the horizontal axis indicates the time including predetermined times t1 to t5. The axis is shown. The time interval between the predetermined times tk to tk + 1 (k is an integer from 1 to 4) is a fixed time.
In FIG. 9, the peak of the current value is seen in the time zone including the times ta, tb, and tc between the times t1 and t5. Therefore, in this time zone, the dust in the gas G1 (gas) is It can be understood that the concentration of fine particles such as is low. However, in the conventional wet-type electrostatic precipitator 1, the effective voltage of the charging voltage (the DC high voltage V1) is controlled to be substantially constant even in such a time zone, so that useless power is consumed.

FIG. 10 is a diagram showing a temporal transition of the current and the voltage (DC high voltage V1) of the wet type electrostatic precipitator 1 applied to the present embodiment in an actual operation.
Specifically, a curve L7 indicating a current and a curve L8 indicating a voltage (DC high voltage V1) are shown between predetermined times t6 and t10.
In FIG. 10, the vertical axis indicates the effective voltage (kV) or the current (mA) of the charging voltage (DC high voltage V1) of the wet type electrostatic precipitator, and the horizontal axis indicates the time including the predetermined time t6 to t10. The axis is shown. The time interval between the predetermined times tm to tm + 1 (m is an integer from 6 to 9) is the same as the time interval between the predetermined times tk to tk + 1 (k is an integer from 1 to 4) in FIG. is there.
In the present embodiment, the effective voltage of the charging voltage (DC high voltage V1) of the wet type electrostatic precipitator 1 assumes two values: an energy saving voltage value V12 and a normal voltage value V11 (V11> V12).

Here, in the present embodiment, in order to realize such variable control shown in FIG. 10, as shown in FIG. 1, the density determination unit 51 includes a density increase determination unit 61 and a density decrease determination unit 62. Prepare.
The concentration decrease determination unit 62 determines that the current value (the current value of the current supplied from the power supply device 2) is equal to or more than the second threshold value C2, such as a time zone including time td, te, or tf. It is determined that the concentration of the fine particles has decreased. When the current is equal to or higher than the second threshold value C2, the concentration of the fine particles is low, and it is not necessary to increase the dust collection efficiency of the fine particles. Therefore, when the current becomes equal to or more than the second threshold value C2, the DC high voltage control unit 42 lowers the charging voltage (DC high voltage V1) of the power supply device 2 from the normal voltage value V11 to the energy saving voltage value V12. Power saving is achieved by performing control.
On the other hand, the concentration increase determination unit 61 determines that the concentration of the fine particles is lower in a time period when the current value (the current value of the current supplied from the power supply device 2) is equal to or less than the first threshold value C1 (see FIG. 6). It is determined that it has risen. When the current is equal to or less than the first threshold value C1, the concentration of the fine particles becomes higher than a certain value, so that the dust collection efficiency of the fine particles needs to be increased. Therefore, when the current becomes equal to or less than the first threshold value C1, the DC high-voltage control unit 42 increases the charging voltage (DC high voltage V1) of the power supply device 2 from the energy-saving voltage value V12 to the normal voltage value V11. Dust collection efficiency is improved by performing control, more specifically, control to increase the voltage set value.
As described above, in the first embodiment, by adopting the two-step voltage of the normal voltage and the energy-saving voltage, the dust collection efficiency can be improved and the power can be saved.

[Effects of Wet Electrostatic Precipitator of First Embodiment]
In summary, the dust collection system S of the first embodiment can provide the following advantageous effects (1) to (5) as compared with the conventional dust collection system.

(1) Conventionally, if the charging voltage of a wet-type electrostatic precipitator is increased, dust collection efficiency can be increased. However, since a large amount of power is consumed, it is uneconomical and energy saving is required in recent years. Was contrary to the circumstances. On the other hand, if the charging voltage is simply lowered, the efficiency of collecting fine particles and dust decreases, so that it is impossible to sufficiently remove fine particles and dust from waste gas.
On the other hand, in the present embodiment, the power supply control device 3 variably controls the charging voltage according to the concentration of the fine particles. Accordingly, power saving can be achieved while suppressing power consumption by suppressing excessively applied DC high voltage, and maintaining dust collection efficiency of fine particles and dust containing heavy metals.

(2) In the present embodiment, the DC high voltage control unit 42 variably controls the DC high voltage applied in accordance with the current detected by the concentration determination unit 51.
As a result, an optimal DC high voltage can be supplied according to the concentration of the fine particles, and when the concentration of the fine particles is low, the excessively applied DC high voltage is suppressed to achieve power saving. can do. Further, when the concentration of the fine particles is high, by supplying a sufficient DC high voltage, it is possible to save power while maintaining the dust collection efficiency of the fine particles containing heavy metals and dust.

(3) In the present embodiment, the DC high-voltage control unit 42 determines whether the current has become equal to or less than the first threshold value C1 and the concentration of fine particles has increased by the concentration increase determination unit 61. Control for increasing the charging voltage is performed.
On the other hand, the direct current high voltage control unit 42 controls the charge voltage of the power supply device 2 to decrease when the concentration decrease determination unit 62 determines that the current is equal to or more than the second threshold value C2 and the concentration of the fine particles has decreased. Is performed.
Thus, the fluctuation of the concentration of the fine particles is determined by determining the vertical movement of the current. When it is determined that the concentration of the fine particles has increased, by supplying a sufficient DC high voltage, it is possible to improve the collection efficiency of the fine particles containing heavy metals and dust. Further, when it is determined that the concentration of the fine particles has decreased, power saving can be achieved by suppressing the supply of an excessively applied DC high voltage.

(4) In the present embodiment, when it is determined that the concentration of the fine particles has increased, the DC high voltage control unit 42 performs control to set the DC high voltage to the first voltage value. On the other hand, when it is determined that the concentration of fine particles has decreased, the DC high voltage control unit 42 performs control to set the DC high voltage to a second voltage value lower than the first voltage value. Accordingly, when it is determined that the concentration of the fine particles has increased, the first voltage value that is a sufficient voltage value can be used to improve the dust collection efficiency of the fine particles containing heavy metals and dust. Further, when it is determined that the concentration of the fine particles has decreased, power saving can be achieved by setting the second voltage value to which the DC high voltage is suppressed to be lower than the first voltage value.

(5) In the present embodiment, the power supply device 2 generates a DC high voltage by reducing the current for a predetermined time during abnormal discharge. Then, during abnormal discharge, the concentration determination unit 51 does not detect a change in the concentration of the fine particles within a predetermined time during which the current is reduced.
Thus, at the time of abnormal discharge in which an excessive voltage is generated, the power supply device 2 can prevent spark discharge by reducing the current for a predetermined time. Then, the concentration determination unit 51 determines whether or not the concentration of the fine particles has been reduced due to the fact that the current has been reduced by the power supply device 2 due to the abnormal discharge. No change in the concentration of fine particles is detected. Therefore, even when abnormal discharge occurs, the dust collection efficiency can be improved while continuously achieving power saving.

[Second embodiment]
Next, a plant 100 to which the dust collection system S of the second embodiment is applied will be described with reference to FIG.
FIG. 11 is a diagram illustrating a configuration example of a plant 100 to which the dust collection system S according to the second embodiment is applied.
The plant 100 illustrated in FIG. 11 includes a dust collection system S, an exhaust gas generation source-side facility 100, an operation control panel 110, and an area monitoring panel 120.

  The exhaust gas source-side equipment 100 is composed of n exhaust gas sources 100-1 to 100-n (n is an integer of 1 or more), and the exhaust gas generated from each of the exhaust gas sources 100-1 to 100-n. Is discharged to the dust collection system S via an exhaust gas duct. The exhaust gas generation source side equipment 100 is composed of, for example, a synthetic quartz manufacturing equipment.

The operation control panel 110 transmits various signals, such as an operation signal, to each of the exhaust gas generation sources 100-1 to 100-n based on a user's instruction operation, and thereby controls each of the exhaust gas generation sources 100-1 to 100-n. Control of operation, for example, control of start and stop of operation.
When receiving the operation control signal indicating that the operation of each of the exhaust gas generation sources 100-1 to 100-n has been started or stopped based on the control of the operation control panel 110, the area monitoring panel 120 collects the operation control signal. Send to system S.

The dust collection system S includes a wet-type electric dust collector 1, a power supply control device 3, a pretreatment device 5, and a post-treatment device 6.
The pretreatment device 5 receives the exhaust gas discharged from the exhaust gas generation source side equipment 100, performs a predetermined pretreatment, and supplies the exhaust gas to the wet-type electrostatic precipitator 1.
The wet electrostatic precipitator 1 processes the exhaust gas supplied from the exhaust gas source side equipment 100 via the pre-processing device 5 under the control of the power supply control device 3 and supplies the processed exhaust gas to the post-processing device 6. I do.
The post-processing device 6 receives the exhaust gas supplied from the wet electrostatic precipitator 1, performs predetermined post-processing, and discharges the same to the outside.

Hereinafter, a dust collection system S according to a second embodiment of the present invention will be described with reference to FIG.
FIG. 12 is a diagram illustrating a configuration example of a dust collection system S according to the second embodiment of the present invention.

  The dust collection system S illustrated in FIG. 12 includes a wet electric dust collection device 1, a power supply device 2, and a power supply control device 3, and is connected to the area monitoring panel 120. The wet electrostatic precipitator 1 and the power supply device 2 are the same as the wet electric precipitator 1 and the power supply device 2 in FIG.

The power supply control device 3 is configured by, for example, a PLC, and includes a TP 41 and a DC high-voltage control unit 42.
About TP41, since it is the same as TP41 of the dust collection system S of FIG. 1, description is abbreviate | omitted.

The DC high voltage control unit 42 is estimated from the operation state of each of the exhaust gas generation sources 100-1 to 100-n based on the load of the exhaust gas from the exhaust gas generation source, specifically, based on the control of the operation control panel 110. The value of the charging voltage from the power supply device 2 is variably controlled according to the load of the exhaust gas.
More specifically, the DC high voltage control unit 42 variably controls the charging voltage according to a predetermined control signal capable of estimating the load of the exhaust gas from the exhaust gas generation source. For this reason, the DC high voltage control unit 42 functionally includes an exhaust gas load change prediction unit 71 that estimates an increase or decrease in the exhaust gas load.
Here, the reason why the function is described is that it is not necessary to limit the implementation form of the exhaust gas load change estimation unit 71 to hardware. That is, the exhaust gas load increase / decrease predicting unit 71 only needs to have the following functions, and the form of realization thereof is not particularly limited, and may be configured by hardware, software, or May be configured.
Note that the DC high voltage control unit 42 may include a concentration determination unit as in the first embodiment, and the load of the exhaust gas estimated from the operation state of the exhaust gas generation sources 100-1 to 100-n. In addition, the value of the charging voltage from the power supply device 2 may be variably controlled according to the concentration of fine particles (dust, dust, etc.) contained in the gas input to the wet-type electrostatic precipitator 1.

The exhaust gas load change prediction unit 71 has a function of predicting a change in the load of exhaust gas discharged from the exhaust gas source in response to a predetermined control signal transmitted from the exhaust gas source-side facility 100. Although the form of realization of the function is not particularly limited, in the second embodiment of the present invention, the function for controlling the start or stop of the operation of each of the exhaust gas generation sources 100-1 to 100-n transmitted from the area monitoring panel 120 is controlled. The function of estimating the load of the exhaust gas discharged from each of the exhaust gas generation sources 100-1 to 100-n based on the operation control signal is provided in the exhaust gas load change prediction unit 71. In other words, a function of predicting an operation control signal for controlling the start or stop of the operation of each of the exhaust gas generation sources 100-1 to 100-n as an index of the exhaust gas load is provided in the exhaust gas load increase / decrease prediction unit 71. ing.
Specifically, the exhaust gas load increase / decrease estimating unit 71 estimates the increase / decrease of the load of the exhaust gas to be processed by the wet-type electrostatic precipitator 1 based on each operation rate of each of the exhaust gas generation sources 100-1 to 100-n. . As an operation rate of each of the exhaust gas generation sources 100-1 to 100-n, for example, the number of each of the exhaust gas generation sources 100-1 to 100-n among the exhaust gas generation sources 100-1 to 100-n is operating. A rate indicating whether or not can be employed.

[Effects of Wet Electrostatic Precipitator of Second Embodiment]
In summary, the dust collection system S of the second embodiment can achieve the following advantageous effects (1) and (2) as compared with the conventional dust collection system.

(1) Conventionally, if the charging voltage of a wet-type electrostatic precipitator is increased, dust collection efficiency can be improved, but power consumption is large and uneconomical, and in recent circumstances, energy saving is required. The result was contrary. On the other hand, if the charging voltage is simply lowered, the efficiency of collecting fine particles and dust decreases, so that it is impossible to sufficiently remove fine particles and dust from waste gas.
On the other hand, in the present embodiment, the power supply control device 3 controls the DC high voltage applied to the electrode rod 24 and the discharge wire 25 according to a predetermined control signal regarding each of the exhaust gas generation sources 100-1 to 100-n. Is variably controlled. Thereby, for example, as an operation state of each of the exhaust gas generation sources 100-1 to 100-n, when the application of the DC voltage is excessive, the application of the DC voltage is achieved while suppressing power consumption by suppressing the DC high voltage. In the state where is required, by maintaining the DC high voltage, it is possible to maintain the dust collection efficiency of fine particles and dust containing heavy metals. In this way, both maintenance of dust collection efficiency and power saving can be realized.

(2) In the present embodiment, the DC high-voltage control unit 42 controls the electrode rod 24 and the discharge wire in accordance with an operation control signal for controlling operation and stop of each of the exhaust gas generation sources 100-1 to 100-n. The DC high voltage applied to 25 is variably controlled.
Thus, by considering the operation and stoppage of each of the exhaust gas generation sources 100-1 to 100-n, an increase or decrease in the load of the exhaust gas (a change in the concentration of fine particles) is predicted. Then, when it is predicted that the load of the exhaust gas will increase, by supplying a sufficient DC high voltage, it is possible to improve the dust collection efficiency of fine particles including heavy metals and dust. Furthermore, when it is determined that the load of the exhaust gas has decreased, power saving can be achieved by suppressing the supply of an excessively applied DC high voltage.

[Third embodiment]
Next, a plant to which the dust collection system according to the third embodiment is applied will be described. The third embodiment is different from the first and second embodiments in that the third embodiment includes an intermittent control unit that controls the charge voltage intermittently, whereas the first and second embodiments control the magnitude of the charge voltage.
The intermittent control unit controls the DC high voltage according to the concentration of fine particles (dust, dust, etc.) contained in the gas input to the wet-type electrostatic precipitator, a predetermined control signal transmitted from the exhaust gas source side equipment 100, and the like. It has the function of applying voltage intermittently. Although the mode of realizing the function is not particularly limited, in the third embodiment of the present invention, the intermittent control unit controls the concentration of the fine particles detected by the concentration determination unit 51 of the first embodiment and the exhaust gas load of the second embodiment. The intermittent interval of the DC high voltage is variably controlled according to the increase or decrease of the load of the exhaust gas predicted by the increase / decrease predicting unit 71.

Hereinafter, with reference to FIG. 13, details of the function of intermittent application by the intermittent control unit will be described.
FIG. 13 is a timing chart for controlling the switching of the operating state by the intermittent control unit. The DC voltage is controlled in accordance with the concentration of fine particles in the exhaust gas and the increase or decrease of the exhaust gas load obtained from the operation rate of the facility on the exhaust gas source side. This is an example of variably controlling the interval at which the voltage is intermittent.
Specifically, a curve L7 indicating the exhaust gas load, a curve L8 indicating the electric power, and a curve L9 indicating the charging voltage (DC high voltage V1) are shown in the time zone of the operation times t21 to t26. In FIG. 13, the vertical axis indicates the exhaust gas load, the electric power, or the effective voltage of the charging voltage (DC high voltage V1) of the wet type electrostatic precipitator 1, and the horizontal axis indicates the time axis.

The intermittent control unit variably controls an intermittent interval of the applied DC high voltage according to the exhaust gas load. In the present embodiment, three patterns in which the interval of the intermittent operation becomes gradually longer are associated with each of the three operation states of the normal operation C1, the first energy-saving operation C2, and the second energy-saving operation C3. The intermittent control unit executes control for intermittently applying a DC voltage at intervals of a pattern corresponding to an operation state estimated from an exhaust gas load state.
The normal operation C1 is associated with “0” as an intermittent interval. When the normal operation C1 is estimated as the operation state, the intermittent control unit applies a DC voltage intermittently such that the interval becomes “0”. Control, that is, control for continuously applying a DC voltage.
The first energy-saving operation C2 is associated with a first interval tg (tg = t23−t22) as an intermittent interval. When the intermittent control unit estimates the first energy-saving operation C2 as the operation state, the first intermittent operation starts. Is performed so that the DC voltage is applied intermittently so as to have the interval tg.
The second energy saving operation C3 is associated with a second interval th (th = t25−t24) as an intermittent interval. When the intermittent control unit estimates the second energy saving operation C3 as the operating state, the second The control for applying the DC voltage intermittently so as to have the interval th is performed.

  Specifically, in the example of FIG. 13, the exhaust gas load is equal to or more than a certain threshold (referred to as a “third threshold” in order to be distinguished from the other thresholds described above) from the operation time t21 to immediately before the operation time t22. Therefore, the intermittent control section 72 estimates the normal operation C1 as the operation state, and executes control to continuously apply the DC voltage.

Immediately before the operation time t22, the intermittent control unit switches the estimation result of the operation state from the normal operation C1 to the first energy-saving operation C2 because the exhaust gas load has dropped below the third threshold. That is, when the exhaust gas load falls below the third threshold and the concentration of fine particles falls below a certain level, it is not necessary to increase the dust collection efficiency of the fine particles so much. Therefore, the intermittent control unit 72 executes control for applying a DC voltage intermittently so as to be the first interval tg. As a result, the power becomes lower as shown by the curve L8 as compared with the conventional continuous DC voltage application state. That is, power saving is achieved as compared with the related art. Since the average value of the predetermined time is used as the power, the power continues to decrease during the operation time t22 to the operation time t23 immediately after the start of the intermittent application.
Thereafter, until immediately before the operation time t24, the exhaust gas load is equal to or higher than a certain threshold value (referred to as a “fourth threshold value” to be distinguished from the other threshold values described above). , The control for intermittently applying the DC voltage at the first interval tg is executed.

Immediately before the operation time t24, the intermittent control unit 72 switches the estimation result of the operation state from the first energy saving operation C2 to the second energy saving operation C3 because the exhaust gas load has dropped below the fourth threshold value. That is, when the exhaust gas load is reduced to the fourth threshold value or less and the concentration of the fine particles is further reduced, there is no problem even if the dust collection efficiency of the fine particles is further reduced. Therefore, the intermittent control unit 72 executes control for applying a DC voltage intermittently so as to have the second interval th. As a result, the power becomes lower as shown by the curve L8, as compared with the conventional continuous DC voltage application state. That is, power consumption is further reduced as compared with the related art. Since the average value of the predetermined time is used as the power, the power continues to decrease during the operation time t24 to the operation time t25 immediately after the intermittent interval changes from the first interval tg to the second interval th. .
After that, since the exhaust gas load keeps the fourth threshold value or less, the intermittent control unit 72 estimates the second energy saving operation C3 as the operation state, and performs the control of intermittently applying the DC voltage at the second interval th. Execute.

[Effects of Wet Electrostatic Precipitator of Third Embodiment]
In summary, the dust collection system S of the third embodiment can provide the following advantageous effect (1) as compared with the conventional dust collection system.

(1) In the present embodiment, the DC high voltage control unit 42 changes the intermittent interval in accordance with the concentration of the fine particles and the increase or decrease of the load of the exhaust gas discharged from each of the exhaust gas generation sources 100-1 to 100-n. Control to be executed.
As a result, an optimal DC high voltage can be supplied in accordance with the load of the exhaust gas. Therefore, when the load of the exhaust gas is low, it is estimated that the concentration of the fine particles is low. By appropriately controlling the intermittent interval, power saving can be achieved. In addition, when the load of the exhaust gas is high, by supplying a sufficient DC high voltage by estimating that the concentration of the fine particles is high, the dust collection efficiency of the fine particles containing heavy metals and dust can be more appropriately maintained. .

Here, with reference to FIG. 14, a comparison is made between the conventional product and the first and third embodiments.
FIG. 14 shows a conventional product (fixed voltage control), the wet type electrostatic precipitator 1 including the DC high voltage control unit 42 of the first embodiment of FIG. 1, and the DC high voltage control unit of the third embodiment of FIG. It is the figure which compared the energy saving shift trigger, the energy saving method, and electric power in each of the wet-type electrostatic precipitators 1 provided with 42.

  As shown in FIG. 14, the wet electrostatic precipitator 1 including the DC high-voltage control unit 42 of the first embodiment has a lower power ratio than a wet electric precipitator including a conventional DC high-voltage control unit. The power saving effect is improved by 16% or more.

  As shown in FIG. 14, the wet electrostatic precipitator 1 including the DC high-voltage control unit 42 according to the third embodiment has a lower electric power than a conventional wet electric precipitator including a DC high-voltage control unit. The power saving effect is improved by 11% or more.

  It should be noted that the present invention is not limited to the above-described embodiment, but includes modifications and improvements as long as the object of the present invention can be achieved.

For example, as described above, an embodiment in which the third embodiment is combined with the second embodiment can be adopted.
In this case, the dust collection system according to the embodiment has both the effects (1) and (2) of the second embodiment and the effect (1) of the third embodiment as compared with the conventional dust collection system. It is possible.
Similarly, an embodiment in which the third embodiment is combined with the first embodiment can be adopted.
In this case, the dust collection system according to the embodiment has both the effects (1) to (5) of the first embodiment and the effect (1) of the third embodiment as compared with the conventional dust collection system. It is possible.

  Further, for example, in the above-described embodiment, the DC high voltage control unit 42 variably controls the charging voltage according to the type between the normal voltage value V11 and the energy saving voltage value V12, but the present invention is not limited to this. For example, the charging voltage variably controlled by the DC high-voltage control unit 42 can be variably controlled not in two stages but continuously in multiple stages or analog.

Returning to FIG. 1, the concentration determination unit 51 includes a concentration increase determination unit 61 and a concentration decrease determination unit 62 in order to determine the index (current) of the concentration of the fine particles.
When the current value (the current value of the current supplied from the power supply device 2) becomes equal to or less than the first threshold value C1 (see FIG. 6), the concentration increase determination unit 61 determines that the concentration of the fine particles has increased. . On the other hand, when the current value (the current value of the current supplied from the power supply device 2) becomes equal to or more than the second threshold value C2 (see FIG. 6), the concentration decrease determination unit 62 decreases the concentration of the fine particles. It is determined that it has been performed.
Then, when the concentration increase determination unit 61 determines that the concentration of the fine particles has increased, the DC high voltage control unit 42 performs control to increase the charging voltage (DC high voltage V1) of the power supply device 2, more specifically, Control to increase the voltage set value is performed. On the other hand, when the concentration decrease determination unit 62 determines that the concentration of the fine particles has decreased, the DC high voltage control unit 42 performs control to decrease the charging voltage (DC high voltage V1) of the power supply device 2, more specifically. Is controlled to lower the voltage set value.

  In the above-described embodiment, the DC high-voltage control unit 42 is configured by a PLC, but is not limited to this. For example, a simple and inexpensive configuration such as a relay control panel can be used.

Further, in the above-described embodiment, the exhaust gas load increase / decrease prediction unit 71 outputs the operation control signal transmitted from the area monitoring panel 120 to control the start or stop of the operation of each of the exhaust gas sources 100-1 to 100-n. The load of the exhaust gas discharged from each of the exhaust gas generation sources 100-1 to 100-n is predicted based on this, but the present invention is not limited to this. For example, the exhaust gas load increase / decrease estimating unit 71 may be configured to transmit each of the exhaust gas generation sources 100-1 to 100-n based on a signal including information such as a flow rate of a raw material supplied to each of the exhaust gas generation sources 100-1 to 100-n. It is also possible to predict the load of the exhaust gas discharged from -1 to 100-n.
That is, by considering the flow rate of the raw material supplied to each of the exhaust gas generation sources 100-1 to 100-n, a change in the load of the exhaust gas is estimated, and a change in the concentration of the fine particles is predicted. When the flow rate of the raw material increases, the load of the exhaust gas is estimated to increase, and by supplying a sufficient DC high voltage, it is possible to improve the dust collection efficiency of fine particles and dust containing heavy metals. . Further, when the flow rate of the raw material is reduced, it is estimated that the load of the exhaust gas is reduced, and power supply can be achieved by reducing the supply of an excessively applied DC high voltage.

DESCRIPTION OF SYMBOLS 1 ... Wet electric dust collection device 2 ... Power supply device 3 ... Power supply control device 4 ... External system 11 ... Upper casing 12 ... Dust collection electrode 13 ... Lower casing 14 ... Frame 21 Upper grid 23 Lower grid 24 Electrode rod 25 Discharge wire 26 Weight 27 Upward spray nozzle 28 Cleaning pipe 31 Switching Switch 32 ... Volume 33 ... Display unit 41 ... TP
42 DC high voltage control unit 51 concentration determination unit 61 concentration increase determination unit 62 concentration decrease determination unit 71 exhaust gas load change prediction unit 72 intermittent control unit 100 ..Equipment on the side of exhaust gas generation source 110 ... Operation control panel 120 ... Area monitoring panel

Claims (3)

A discharge electrode to which a DC high voltage is applied,
By a negative corona discharge generated between the discharge electrode based on the DC high voltage, a dust collection electrode for collecting fine particles contained in exhaust gas discharged from an exhaust gas generation source,
A power control device for an electrostatic precipitator comprising:
A predetermined control signal relating to the exhaust gas generation source is received, and in response to the control signal, the voltage of the DC high voltage applied to the discharge electrode is variably controlled in a state where there is a load of the exhaust gas from the exhaust gas generation source. DC high voltage controller,
With
It said predetermined control signal, Ri information der relating to the concentration of particulates in the exhaust gas based on the current value of the negative corona discharge,
The DC high-voltage control unit controls the variable control to increase the DC high voltage from an energy-saving voltage value to a normal voltage value when the current value becomes equal to or less than a first threshold value, and the current value is set to a second value. Control to decrease the DC high voltage from the normal voltage value to the energy saving voltage value when the voltage is equal to or more than the threshold value, and
The power supply control device for an electric dust collector, wherein the DC high voltage control unit is configured to reduce a current during abnormal discharge and not detect the current value while the current is reduced . A discharge electrode to which a DC high voltage is applied,
By a negative corona discharge generated between the discharge electrode based on the DC high voltage, a dust collection electrode for collecting fine particles contained in exhaust gas discharged from an exhaust gas generation source,
A power control method for an electrostatic precipitator comprising:
A predetermined control signal relating to the exhaust gas generation source is received, and in response to the control signal, the voltage of the DC high voltage applied to the discharge electrode is variably controlled in a state where there is a load of the exhaust gas from the exhaust gas generation source. Steps,
Including
Said predetermined control signal, Ri concentration Information der of the fine particles of the exhaust gas based on the current value of the negative corona discharge,
As the variable control, a control for increasing the DC high voltage from an energy-saving voltage value to a normal voltage value when the current value is equal to or less than a first threshold, and the control when the current value is equal to or more than a second threshold value. Control to lower the DC high voltage from the normal voltage value to the energy-saving voltage value,
In the variable control, a power supply control method for an electrostatic precipitator is characterized in that the current is reduced during abnormal discharge and the current value is not detected while the current is reduced . The method further includes controlling the DC high voltage to be applied intermittently to the discharge electrode, and performing a control that varies an intermittent interval in accordance with a predetermined control signal regarding the exhaust gas generation source.
The power control method for an electrostatic precipitator according to claim 2, comprising:

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