JP3053482B2 - Method for controlling injection amount of aluminum compound in treatment of wastewater containing fluorine and aluminum and fluorine removing device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to fluorine (herein "fluoride ion") and aluminum (herein "aluminum ion").
More particularly, the present invention relates to a wastewater treatment method for removing a fluorine content in wastewater containing fluorine and aluminum by an aluminum compound, and more particularly to a method for controlling the injection amount of the aluminum compound. Related to the method of controlling.

[0002]

2. Description of the Related Art Flue gas desulfurization wastewater (hereinafter referred to as "desulfurization wastewater") generated in a coal-fired power plant contains fluorine, and an aluminum compound is used to reduce the fluorine content in such wastewater. BACKGROUND ART Wastewater treatment methods for coprecipitating with aluminum hydroxide and removing in the form of coprecipitated precipitates are widely used.
Here, the “aluminum compound” may be anything that can produce the above “aluminum hydroxide”, such as aluminum sulfate, polyaluminum chloride,
Alum or the like can be mentioned as an example, and it may be used in the form of a solution or in the form of a solid. Of these aluminum compounds, aluminum sulfate is generally used.

[0003] However, the fluorine concentration in the desulfurization wastewater in a coal-fired power plant depends on, for example, the type of coal (coal type) used for power generation, the type of flue gas desulfurization equipment (soot separation method or soot mixing method), Furthermore, even if the type of coal is the same, it generally differs depending on the power generation load.

Heretofore, in the treatment using such a fluorine-removing apparatus for the fluorine-containing wastewater, the actual amount of the chemical has been adjusted manually.

FIG. 4 is a graph showing, by way of example, a model representation of the change in the fluorine concentration of the desulfurization wastewater with the elapse of the operation time of a coal-fired power plant. The horizontal axis of this figure represents the operation time, and the vertical axis represents the fluorine concentration. As shown in FIG. 4, the fluorine concentration in the desulfurization wastewater fluctuates with the elapse of the operation time. However, conventionally, the analysis of fluorine requires time and labor, and therefore, based on the expected fluorine concentration (A), In many cases, the fluorine removing device was operated while injecting an aluminum compound such as aluminum sulfate at a constant injection rate.

[0006]

In this case, the actual fluorine concentration in the wastewater is lower than the expected fluorine concentration (A) (C).
If [the peak of the concentration fluctuation is below], excessive injection of aluminum sulfate is caused, which leads to an increase in running cost. Conversely, the actual fluorine concentration is the expected fluorine concentration (A)
If the concentration (B) is higher (that is, the peak of the concentration fluctuation is higher), the amount of the aluminum compound injected becomes insufficient,
The efficiency of fluorine removal is reduced, and the quality of treated water is deteriorated, so that the discharge standard water quality cannot be satisfied. Conventionally, such inconveniences have been frequently observed.

[0007] It has also been clarified that aluminum (aluminum ions) is present in the desulfurization wastewater, and that this aluminum can be effectively used for removing fluorine.
However, the aluminum concentration in the desulfurization wastewater also generally varies depending on the operating conditions of the flue gas desulfurization unit, the type of coal used, and the like.

For this reason, when the aluminum content in the desulfurization wastewater is to be effectively used for removing fluorine, a certain standard of the aluminum concentration in the desulfurization wastewater (generally, a planned value) is assumed, and the aluminum compound injection amount of the shortage is assumed. It is common to set In this method, as described above, there are problems such as excess and deficiency of the aluminum compound, an increase in operating cost, and an inability to stabilize the quality of treated water.

Moreover, in the above case, the aluminum concentration in the desulfurization wastewater does not always fluctuate in synchronization with the fluorine concentration.
It often changes with little correlation. Accordingly, the desulfurization wastewater treatment apparatus requires an operation management different from that of the conventional general wastewater treatment apparatus, for example, the measurement of only the fluorine concentration in the wastewater cannot determine the appropriate amount of the aluminum compound to be injected.

In order to stabilize the quality of the treated water, an excessive injection of the aluminum compound has been inevitable, resulting in a problem of an increase in cost due to an increase in the consumption of the aluminum compound. In addition, in order to absorb fluctuations in the concentration of fluorine and aluminum in influent wastewater and to make the properties of influent wastewater as uniform as possible,
It was necessary to provide a sufficiently large storage tank and a homogenizing facility for it in the former stage.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to solve the above-mentioned problems, and the main object of the present invention is to minimize the amount of aluminum compound to be injected in a fluorine-containing wastewater treatment process. Aims to stabilize the quality of treated water.

In order to solve the above-mentioned problems, a control means for controlling the amount of the aluminum compound injected corresponding to the fluctuation of the flow rate of the wastewater flowing into the fluorine removing device, the fluctuation of the fluorine concentration in the wastewater and the fluctuation of the aluminum concentration of the wastewater. And devising means for minimizing the necessary amount so that the injection amount of the aluminum compound is not excessive,
Even if fluctuations in treated water quality due to fluctuations in the fluoride ion concentration and aluminum ion concentration of wastewater are compared with target values and fed back, the wastewater treatment must be controlled at least in order to go through a process of reaction → pH adjustment → precipitation and separation. It was necessary to devise a means to solve the problem that was significantly larger.

[0013]

Means for Solving the Problems The present inventors have made intensive studies from such a viewpoint, and as a result, have completed the present invention.

That is, according to the present invention, a wastewater flow rate detector for detecting the flow rate of inflow wastewater, a wastewater fluorine concentration analyzer for detecting the fluorine concentration of inflow wastewater, and a wastewater aluminum concentration for detecting the aluminum concentration of inflow wastewater In a control method of a fluorine removing device for removing fluorine from waste water containing fluorine and aluminum provided with an analyzer, an aluminum concentration required for fluorine removal is predetermined by a fluorine concentration signal from the fluorine concentration analyzer for waste water. An aluminum compound is calculated by a calculation formula or a multiplication coefficient, by subtracting the aluminum concentration signal from the wastewater aluminum concentration analyzer from the calculated required aluminum concentration, and further multiplying by the inflow wastewater flow signal from the wastewater flow detector. Aluminization in the treatment of wastewater containing fluorine and aluminum for calculating and outputting the injection amount The method of the object injection amount is provided.

In the method for controlling the amount of aluminum compound injected in the treatment of waste water containing fluorine and aluminum,
The target fluorine concentration of the treated water is set to a positive value within the allowable limit of drainage which is not zero, and the polarity of the deviation between the target fluorine concentration value and the measured fluorine concentration of the treated water and the magnitude thereof indicate the amount of the aluminum compound injected. An arithmetic circuit for calculating a multiplication coefficient for correcting the arithmetic output of the above is provided, and the integrated value obtained by the integrating circuit for integrating the inflow wastewater flow rate is an effective retention volume value of the fluorine component removing device up to the fluorine concentration detection position of the treated water. Each time the comparison circuit determines that the temperature has reached the above, the fluorine component removing device has a function of calculating and correcting the correction multiplication coefficient and resetting the integrated value, and multiplies the aluminum compound injection amount by the correction multiplication coefficient. It is preferable to control the aluminum compound injection amount by using the set value as a remote setting value of the aluminum compound injection amount controller.

Further, according to the present invention, there is provided a fluorine removing device including a primary treatment device and a secondary treatment device having a reaction tank for injecting an aluminum compound, wherein a flow rate detector of an inflowing wastewater is provided upstream of the reaction tank. And a wastewater fluorine concentration analyzer and a wastewater aluminum concentration analyzer, and a treated water fluorine concentration analyzer is provided between the primary treatment device and the secondary treatment device or downstream of the secondary treatment device as required. Computing means for performing control according to any one of the above-described embodiments of the method for controlling the amount of aluminum compound injected according to the present invention, and further comprising: injecting an aluminum compound into the reaction tank in accordance with a result of computation by the computing means. A fluorine compound removing device provided with an aluminum compound injecting means for removing the fluorine.

In the present invention, as described above, the "aluminum compound" is not limited as long as it can produce "aluminum hydroxide", and examples thereof include aluminum sulfate, polyaluminum chloride, and alum. And it may be used in the form of a solution or a solid. Also in the present invention, it is common to use aluminum sulfate.

Hereinafter, the present invention will be described specifically and in detail, focusing on desulfurization wastewater as the wastewater to be treated.

First, the fluorine concentration (F) of the wastewater flowing into the fluorine removal device is measured, and the aluminum concentration required for fluorine removal (that is, the amount of aluminum, which is temporarily referred to as “total aluminum amount”) is measured in the actual machine. The calculation formula [F
(X)] or a simple multiplication coefficient (α) to calculate according to the above-mentioned fluorine concentration, and in some cases, further measure the aluminum concentration (Al ′, which is temporarily referred to as “aluminum content”) in the inflow wastewater. Then, this value is subtracted from the total aluminum amount, and the “deficient aluminum amount” to be injected is set.
Is calculated, and this “deficient aluminum amount” is converted to an aluminum compound amount.

Since the amount of inflow wastewater also fluctuates, the amount of aluminum compound is multiplied by the amount of inflow wastewater flow signal (Q) from the wastewater flow detector to obtain the amount of aluminum compound injected into the inflow wastewater at that time. The injection amount of the aluminum compound is controlled.

This aluminum compound injection amount is preferably multiplied by a feedback correction coefficient (β) as an injection result, and the obtained value is used as a remote setting value of the aluminum compound injection flow rate controller,
Control the amount of aluminum compound injected.

In order to prevent the aluminum compound from being excessively injected, the target fluorine concentration (f) of the treated water is set to an allowable positive value other than zero, and the target fluorine concentration (f ') of the treated water is measured. (F'-f) and polarity (±)
, It is preferable that the multiplication coefficient (β) is feedback corrected.

However, as described above, the wastewater into which the aluminum compound has been injected not only requires a considerable time delay before flowing out as treated water, but also this time delay greatly varies depending on the flow rate of the inflowing wastewater. For,
Instead of using normal feedback control to ensure feedback corresponding to past control points,
The effective retention volume (Q _s ) in the fluorine removal system up to the fluorine concentration detection position of the treated water is determined, and every time the integrated value (Q _T ) of the inflow wastewater reaches the effective retention volume (Q _s ) , It is preferable to perform an operation for correcting the multiplication coefficient (β). Note that the effective retention volume refers to the actual passage of the treated water (the primary treated water and the secondary treated water in the following embodiments) up to the fluorine concentration detection position in the fluorine content removing device. The volume of the part.

In summary, the aluminum compound injection amount (Al) is calculated according to one of the following equations. In the following formula, K represents a constant peculiar to the apparatus, and γ represents the concentration (or density) of the aluminum compound solution actually injected.

[0025]

## EQU1 ## [Detailed expression] Al = K. [F (x) -Al ']. Q..beta..1 / .gamma.

[0026]

[Equation 2] [Simplified formula] Al = K · [F · α−Al ′] · Q · β · 1 / γ

[0027]

According to the method for controlling the injection amount of aluminum compound in the fluorine removing apparatus having the above-described structure, the method for controlling the fluctuation of the fluorine concentration and the aluminum concentration and the fluctuation of the flow rate of the wastewater due to the fluctuation of the power generation load of the desulfurization wastewater is used. The optimum amount of the aluminum compound can be immediately and automatically injected by the accurate calculation formula [F (x)] and the multiplication coefficient (α) obtained in
In an intermediate-load coal-fired power plant having a large load variation, the cost of chemicals such as aluminum compounds can be significantly reduced as compared with the related art.

Further, the control by the aluminum compound injection amount correction mechanism based on the fluorine concentration of the treated water effectively acts on the fluctuation of the composition ratio of the wastewater due to the fluctuation of the coal type and the change of the blend ratio of the coal type. Not only eliminates the need to inject excessive amounts of aluminum compound to ensure the treated water quality on the safe side as in the past, but also allows the operator to change the setting of the amount of injected aluminum compound according to fluctuations in the power generation load. You don't have to do it each time.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail by way of embodiments with reference to the drawings, but the present invention is not limited to the embodiments.

FIG. 1 is a flowchart showing each processing step and a signal system in an example of a wastewater treatment apparatus which is a fluorine removal apparatus used in the present invention.

This device is a desulfurization wastewater treatment device,
In FIG. 1, the left side from the position where the primary treatment water 16 flows out is a primary treatment unit, and the right side is a secondary treatment unit (softening unit).
It is.

This primary treatment apparatus has a reaction tank 6 (injecting an aluminum compound), a first flocculation tank 7 (for example, using an anionic polymer flocculant as an auxiliary), and a first precipitation tank 15. Aluminum compound storage tank 1 as ancillary equipment
2, aluminum compound injection pump 13, aluminum compound injection control valve 9, pH adjuster injection valve 1
8 (for example, caustic soda is injected), and a pH adjusting agent storage tank (not shown). In the first settling tank 15,
A sludge extraction pump 17 is provided. Reaction tank 6
It has a pH adjusting function by the pH adjusting agent injection valve 18 (adjusts the pH value to about 6 to about 8), and is provided with a pH detector 19.

The secondary treatment apparatus includes a softening tank 31 (for example, injecting sodium carbonate and caustic soda), a second flocculation tank 32 (for example, using an anionic polymer flocculant as an auxiliary), and a second precipitation tank 33. Have. In the softening tank 31, a pH detector 36 is provided.
The second settling tank 33 is provided with a sludge pulling pump 3
5 are provided.

The desulfurization wastewater generally contains a magnesium component (magnesium ion).
To sodium carbonate and inject caustic soda to pH
If the pH is adjusted to exceed 10 (eg, about 10.5), a precipitate of magnesium hydroxide will form, but a significant portion of the fluorine remaining in the primary effluent will probably be absorbed at the same time. It precipitates and therefore the fluorine concentration in the secondary treatment water is even lower.

In the above-mentioned fluorine removing apparatus, an automatic analyzer 3 for measuring the fluorine ion concentration of the inflowing wastewater 2 continuously or at short intervals (for example, utilizing the ion electrode method, Japanese Patent Laid-Open No. 3-51754). The fluorine concentration F of the wastewater is measured according to the above-mentioned method, and a signal of this F is input to, for example, a computer 100 as arithmetic means, and the necessary total aluminum amount is calculated by the CPU of the computer according to the following equation.

[0036]

F (x) = a · logF ² + b · logF + C [where a, b and C are constants]

However, since this calculation is complicated, it is convenient to use the following coefficient α. The coefficient α is obtained from the results of actual equipment and various field tests, and can be easily used. The required total aluminum amount can be obtained as F × α. Note that α is stored in the memory unit of the computer 100, and its value is in the range of 1.7 to 4.0.

The aluminum concentration Al ′ is measured by a wastewater aluminum concentration automatic analyzer 4 for continuously or at short time intervals measuring the aluminum ion concentration of the inflowing wastewater 2, and a signal of this Al ′ is input to the computer 100. And [(F (x) -Al ′] or [F · α-
Al ′] is calculated, and the aluminum concentration to be increased by the implantation is calculated.

This value is multiplied by the CPU by an instantaneous flow rate signal Q from the flow rate detector 1 for detecting the flow rate of the inflow wastewater 2, and furthermore, measurement of various instruments such as analytical instruments and measuring instruments used in the apparatus. Device-specific constant K determined by range, control range and unit of use (stored in memory)
And the instantaneous aluminum compound injection amount when the aluminum compound concentration is 100% is calculated.

Further, the concentration signal γ of the aluminum compound concentration detector 11 for measuring the actual aluminum compound solution concentration is input to the computer 100, and the instantaneous aluminum compound injection amount when the above-mentioned aluminum compound concentration is set to 100% by the CPU. Is multiplied by 1 / γ to calculate the aluminum compound injection flow rate at the actual solution concentration.

When a solution having a constant aluminum compound concentration is prepared, 1 / γ is included in the internal constant of the arithmetic unit, and the aluminum compound concentration detector 11 can be omitted.

Next, a preferred embodiment using the injection amount correction multiplication coefficient β in the above equation (1) or (2) will be described, for example, with reference to the flowchart of FIG. I have.

Β is expressed by the following equation.

[0044]

## EQU4 ## β = 1 + RV _(tn-1) +. DELTA.RV _(tn) [where, .DELTA.RV _(tn) = k (F'-f) _(tn) . ]

In this equation, the deviation (F ') between the fluorine concentration signal F' from the primary treatment water fluorine concentration analyzer 14 for measuring the fluorine ion concentration of the primary treatment water 16 and the fluorine concentration target value f of the primary treatment water 16 is obtained. −f) is ΔRV _(tn) =
k (F'-f) _(tn) . k is a proportional coefficient for each correction value. The cumulative value of the correction values up to the previous time is R
V _(tn-1) .

In contrast to the equations (1) and (2) which are always calculated, the equation (4) is based on the fact that the integrated value Q _T of the inflowing wastewater amount is the effective accumulated volume Q _S (in this case, FIG. Is calculated every time the amount reaches the position of the fluorine concentration analyzer 14). In other words, the coefficient β is modified to a new value when it becomes a Q _T ≧ Q _S, is fixed until the next time. Further, the reset to zero inflow wastewater amount integrated value Q _T at the same time, restarts the integration.

Next, a program processing procedure performed by the computer 100 will be described with reference to the flowchart of FIG. At some point, when it is detected that the apparatus is in operation [Step (1)], the integrated value of the inflowing wastewater amount up to the previous cycle by the integrating circuit is used by the fluorine removing apparatus to reach the fluorine concentration detecting position of the treated water. The comparison circuit determines whether or not the value of the effective retention volume has been reached [step (2)]. If the value has not yet reached, the same stored β value as in the previous cycle is used, and "expression 2"
The operation of the formula (Equation 1) is performed by an arithmetic circuit [Step (3)], and an aluminum compound is injected into the reaction tank 6 based on the result. Next, the current inflow wastewater flow rate is added to the same integrated value up to the previous time (step (4)).

[0048] repeat such a cycle, if it decided to satisfy the conditions of Q _T ≧ Q _S in step (2),
The calculation of Expression 4 is performed by a calculation circuit [Step (5)], and a new injection amount correction multiplication coefficient β is obtained, and this is used for the calculation of Step (3) from the next cycle. In this case, the integrated value of the inflow wastewater flow rate in the integrating circuit is reset to zero [step (6)]. From there, step by using the new "β" (2) → step (3) → step repeating the cycle of (4), If you are satisfied with the conditions of re-Q _T ≧ Q _S step (5) → step (6) And proceed. That is, the processing procedure is repeated.

In the above case, the feedback control is performed using the primary treatment water 16 to measure the fluorine concentration for obtaining the injection amount multiplication coefficient β.
Can be controlled in exactly the same way by measuring the fluoride ion concentration of the treated water with the secondary treated water fluorine concentration analyzer 34 and feeding it back as F '. In the latter case, the effective residence volume Q _S is the effective retention volume to the position of the secondary treated water fluorine concentration analyzer 34 in the fluorine content removing device of FIG.

Further, both the primary treatment water fluorine concentration analyzer 14 and the secondary treatment water fluorine concentration analyzer 34 may be provided. In this case, for example, when the variation per unit time of the inflow wastewater flow rate and the influent wastewater fluoride ion concentration exceeds a certain value, the primary treatment water fluorine concentration signal from the primary treatment water fluorine concentration analyzer 14 is multiplied by the injection amount. The coefficient β may be used to determine the coefficient β, and in other cases, the secondary treatment water fluoride ion concentration signal from the secondary treatment water fluorine concentration analyzer 34 may be used to determine the injection amount multiplication coefficient β. In this case, since the former case has a smaller effective retention volume than the latter case, there is an advantage that it is possible to respond to a rapid change in the inflow wastewater flow rate or the influent wastewater fluoride ion concentration in a shorter time. In addition, when the fluctuation of the inflow wastewater flow rate and the inflow wastewater fluoride ion concentration is not so large, the advantage that the feedback control can be performed more precisely by the secondary treatment water fluoride ion concentration signal which is more closely related to the desired treatment water quality can be secured. Also, for this purpose, the treated water fluorine concentration analyzer is shared, and the sample line can be switched alternately, so that the primary treated water fluoride ion concentration and the secondary treated water fluoride ion concentration can be one treated water fluoride concentration analyzer. The measurement may be performed.

To set the treated water fluorine concentration target value f to a positive value within the allowable limit of drainage which is not zero, specifically, is set higher than the measurement limit value (lower limit) of the fluorine concentration analyzer 14 or 34, This means setting the value to a value larger than the error value and within the allowable discharge limit, in order to perform control to avoid excessive injection of the aluminum compound. because,
If the f value is set to be equal to or less than the measurement limit value of the fluorine concentration analyzer 14 or 34 plus the measurement error value, the excess injection will cause F ′ to fall below the measurement limit value of the fluorine concentration analyzer 14 or 34 plus the measurement error value. This is because, when this happens, it becomes impossible to determine whether the injection is excessive or not, and the degree of excessive injection.

The aluminum compound injection amount Al obtained by the equation (1) or (2) thus obtained is set as a remote set value of the aluminum compound injection flow rate controller 10 and the aluminum compound injection flow rate detector 8 Injection amount measured by computer and computer 100
And output as an opening command MV value (operation output value, manipulating value) to the injection amount control valve 9. The control valve 9 of the drive unit for controlling the injection amount is not necessarily a control valve. For example, a plunger type metering pump may be used as the aluminum compound injection pump 13 without the control valve. A combination of stroke control and rotation speed control with the type metering pump may be used.

FIG. 3 shows, by way of example, the fluorine concentration and the aluminum concentration in the desulfurization wastewater, the fluorine concentration of the secondary treatment water obtained from the second precipitation tank (in the case of “no feedback” and the fluorine concentration of the secondary treatment water). FIG. 9 is a graph illustrating the temporal variation of “with feedback”). In FIG. 3, the horizontal axis represents the number of operating days, and the vertical axis represents the concentration. This graph is a semi-log graph, and the density scale on the vertical axis is a logarithmic scale.

In FIG. 3, curve (a) shows the aluminum concentration of the wastewater, curve (b) shows the fluorine concentration of the wastewater, and curve (c) shows the fluorine concentration of the secondary treated water in the case of "no feedback". And curve (d) represents the fluorine concentration of the secondary treated water in the case of “with feedback”.

It can be seen that the control with "feedback" is preferable because the fluctuation range of the fluorine concentration of the secondary treatment water is smaller than the control without "feedback".

In the present invention, the arithmetic operation of the expression (Equation 1) or (Equation 2) can be performed not only by a dedicated operation unit but also by a control computer using a commercially available one-loop operation which can perform the above operation.
It can be used as a controller, or as an arithmetic circuit for a personal computer or sequencer.

[0057]

As described above, according to the present invention, fluctuations in the properties of the fluorine-containing wastewater and fluctuations in the flow rate of the wastewater can be prevented.
It is possible to inject an appropriate amount of aluminum compound in near real time and, if necessary, to prevent excessive injection of aluminum compound with a delicate correction and correction mechanism. Thus, the amount of use of the aluminum compound and other chemicals can be significantly reduced.

Automatic follow-up to fluctuations in the flow rate and properties of the inflow wastewater is remarkably improved as compared with the related art, so that the burden on the operator is reduced.

[Brief description of the drawings]

FIG. 1 is a flowchart showing each processing step and a signal system in an example of a wastewater treatment apparatus including a fluorine content removing apparatus used in the present invention.

FIG. 2 is a flowchart showing a program processing procedure of a control system based on an injection amount correction multiplication coefficient β.

FIG. 3 is a diagram for explaining the wastewater treatment effect when the control method according to the present invention is used, and shows the fluorine concentration and aluminum concentration in the desulfurization wastewater, and the fluorine concentration of the secondary treatment water obtained from the second precipitation tank (without feedback). With and with feedback)
FIG. 5 is a graph showing the time-dependent fluctuation of.

FIG. 4 is a graph schematically showing a change in the fluorine concentration of the desulfurization wastewater with the elapse of the operation time of the coal-fired power plant.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 Wastewater flow detector 2 Inflow wastewater 3 Wastewater fluorine concentration analyzer 4 Wastewater aluminum concentration analyzer 6 Reaction tank 7 First coagulation tank 8 Aluminum compound flow detector 9 Aluminum compound injection control valve 10 Aluminum compound injection controller 11 Aluminum compound concentration detection 12 Aluminum compound storage tank 13 Aluminum compound injection pump 14 Primary treatment water fluorine concentration analyzer 15 First precipitation tank 16 Primary treatment water 17 Sludge extraction pump 18 pH adjusting agent injection valve 19 pH detector 31 Softening tank 32 Second flocculation tank 33 Second precipitation tank 34 Secondary treatment water fluorine concentration analyzer 35 Sludge extraction pump 36 pH detector 37 Secondary treatment water 100 Computer

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Mamoru Torio 1 at Kita-Kanzan, 20-chome, Odaka-cho, Midori-ku, Nagoya-shi, Aichi Power Equipment Research Institute, Chubu Electric Power Co., Inc. (72) Inventor (72) Inventor Takada ▲ Toki ▼ Male 5-5-1, Hongo, Bunkyo-ku, Tokyo Organo Stocks, 20-1, Kita-Sekiyama, Odaka-cho, Midori-ku, Nagoya-shi, Aichi, Japan In-company (72) Inventor Hidetoshi Takami 5-5-16-1 Hongo, Bunkyo-ku, Tokyo Organo Co., Ltd. (56) References JP-A-60-202789 (JP, A) JP-A-60-197293 (JP, A) Japanese Patent Application Laid-Open No. Sho 58-1443878 (JP, A) Japanese Utility Model Application Sho 52-24762 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) C02F 1/00-1/78

Claims (3)

(57) [Claims] 1. A wastewater flow rate detector for detecting a flow rate of an inflowing wastewater, a wastewater fluorine concentration analyzer for detecting a fluorine concentration of the inflowing wastewater, and a wastewater aluminum concentration analyzer for detecting an aluminum concentration of the inflowing wastewater. And a control method of a fluorine removing device for removing fluorine from aluminum-containing wastewater, wherein a fluorine concentration signal from the wastewater fluorine concentration analyzer is used to determine an aluminum concentration required for fluorine removal by a predetermined calculation formula or a multiplication coefficient. Calculate and subtract the aluminum concentration signal from the wastewater aluminum concentration analyzer from the calculated required aluminum concentration, and further calculate and output the aluminum compound injection amount by an arithmetic circuit that multiplies the inflow wastewater flow signal from the wastewater flow detector. A method for controlling the amount of aluminum compound injected in treating wastewater containing fluorine and aluminum. 2. The target fluorine concentration value of the treated water is set to a positive value within the allowable limit of drainage which is not zero, and the polarity and magnitude of the deviation between the target fluorine concentration value and the measured fluorine concentration value of the treated water are set. And a calculation circuit for calculating a correction multiplication coefficient for correcting the calculation output of the aluminum compound injection amount, wherein the integrated value obtained by the integration circuit for integrating the inflow wastewater flow rate is such that the fluorine content up to the fluorine concentration detection position of the treated water is obtained. Each time the comparison circuit determines that the effective retention volume value of the removing device has been reached, the fluorine component removing device is provided with a function of calculating and correcting the correction multiplication coefficient and resetting the integrated value. The aluminum compound injection amount is controlled by using a value obtained by multiplying the aluminum compound injection amount by the correction multiplication coefficient as a remote setting value of an aluminum compound injection amount controller. Of controlling the amount of aluminum compound injected in the treatment of wastewater containing fluorine and aluminum described above. 3. A fluorine removal device including a primary treatment device and a secondary treatment device having a reaction tank for injecting an aluminum compound, wherein a flow rate detector of an inflowing wastewater and a fluorine concentration analyzer of a wastewater upstream of the reaction tank. And a wastewater aluminum concentration analyzer, wherein a treated water fluorine concentration analyzer is provided as necessary between the primary treatment device and the secondary treatment device, downstream of the secondary treatment device, or both. An arithmetic means for performing the method of controlling the injection amount of aluminum compound according to any one of 1 and 2, further comprising an aluminum compound injection means for injecting an aluminum compound into the reaction tank in accordance with a calculation result by the arithmetic means. A fluorine component removing device, comprising: