JPS59230698A - Apparatus for controlling chemical agent injecting amount in sludge treating equipment - Google Patents

Abstract

PURPOSE:To perform stable control by controlling the injection amount of a chemical agent, by mounting a charged sludge dry matter operator, a first pH meter for measuring the pH of sludge, a ferric chloride injecting amount controller and a second pH meter for measuring the pH of sludge after the injection of slaked lime. CONSTITUTION:The control of a ferric chloride injecting amount is achieved by such a process that the amount proportional to the dry matter of sludge charged to a ferric chloride injecting tank 1 is used a basic amount and the amount corresponding to the difference of the measured pH value in the tank 1 and a pH set value preset, for example, to 4.5-5.5 is added to said basic amount as a feedback amount while an electromotive valve 11a is controlled on the basis of the sum amount thereof. The control of a slaked lime injecting amount is performed in such a process that the amount proportional to the dry matter of the sludge charged to a slaked lime injecting tank 2 used as a basic amount and the amount corresponding to the difference of the measured pH value in the slaked lime injecting tank 2 and a pH value preset, for example, to 11-12 is added as a feedback amount while an electromotive valve 11a is controlled on the basis of the sum amount thereof.

Description

[Detailed Description of the Invention] This invention is a method for controlling the injection amount of these chemicals in a sludge treatment facility in which sludge is tempered by introducing ferric chloride and then adding slaked lime. This invention relates to a chemical injection amount control device.

Conventionally, there has been a device of this type as shown in FIG.

In the figure, 19 is a pear product injection tank consisting of a ferric chloride injection tank 1 and a slaked lime injection tank 2).

The sludge first enters the ferric chloride injection tank 1 through the input sludge pipe 3, and is mixed with ferric chloride by the action of the stirring device 18 through the ferric chloride injection pipe 5. The sludge then enters the slaked lime supply tank 2, and is mixed with the slaked lime supplied through the slaked lime injection pipe 6L by the action of the stirring device 18, whereby the sludge is refined. The tempered sludge is sent to the dewatering process through a feed sludge line 4 to a dehydrator (not shown).

20 is an input sludge flow meter, and 21 is an input sludge concentration meter, both of which are installed in the input sludge pipe line 3.

Reference numeral 26 denotes a computing unit which receives the measured values of the input sludge flow meter 20 and the input sludge concentration meter 21. 27 and 28 are ratio setters, both of which are connected to the output of the calculator 26 as input. lla is a heart valve, and 12 is a ferric chloride flow meter, both of which are installed in the ferric chloride injection pipe 5. 9 is a ferric chloride injection amount controller, which is connected as a force to the ratio setting device 27 and the output needle of the ferric chloride flowmeter 12.
, the output is connected to the electric valve 11a. 11b is an electric valve, and 17 is a slaked lime flow meter, both of which are installed in the slaked lime entrance pipe 6. Reference numeral 15 denotes a slaked lime injection amount regulator, which controls a ratio setting device 28 and a slaked lime flow rate tt17. The output is connected as an input, and the output is connected to an electric valve 11b.

Next, the operation will be explained. The amounts of ferric chloride and slaked lime to be injected are proportional to the solid content in the input sludge, and by injecting these amounts, the sludge is refined in a predetermined manner.

Qlr o = 1 − Ci 11 Qi
-” (11QcB=2”
Ci @Qi...-121 here QF
: Ferric chloride injection amount Q () a : Slaked lime injection amount Qi : Input sludge flow rate C1 : Input sludge concentration k 1 * k 2 : Proportionality constant (11, In equations +21, input sludge flow rate (Q i) and input sludge Concentration (Ci) is calculated by subtracting the sludge flow rate by 1 person and 2
The calculation of 1° (CL·Qi) obtained as the output signal of the input sludge concentration meter 21, in other words, the calculation of the amount of solid matter (dry matter) in the input sludge, is performed by the calculator 26. (11
In the equation, the proportionality constant (kl) is predetermined in the ratio setter 27, and the calculation on the right side is performed by the ratio setter 2T. Therefore, (QFe) is obtained as the output of the ratio setting device 2't. This becomes the setting input for the ferric chloride purchase amount controller 9. and the output of the device 27.

Using the output of the ferric chloride flow rate B↑12, an operation is performed to set the opening degree of the electric nozzle 11a. Sanru. 1k (2
), the proportionality constant (k2) is preset in the ratio setter 2B, and the calculation on the right side is performed by the ratio setter 28.
, fl, L [therefore (Qaa) is the ratio setter 28
The output of j and n becomes the setting input for the slaked lime injection amount controller 15. In the slaked lime injection amount controller 15, the output of the ratio setting device 28.

Using the output of the slaked lime flowmeter 17, the electric valve 11b
An operation is performed to set the opening of the slaked lime, thereby adjusting the amount of slaked lime to be injected to a predetermined value.

Since the conventional chemical injection amount control device for sludge treatment equipment is configured as described above, the amount of chemicals purchased is only adjusted according to the amount of solid matter in the sludge, and the amount of chemicals purchased is adjusted in accordance with the amount of chemical consumption. No consideration was given to the alkalinity of the sludge, and as a result, the ever-changing alkalinity of the sludge caused problems and the amount of chemicals injected was either too much or too little, making it impossible to obtain a good sludge conditioning effect.
do not have.

1'1c If the chemical injection rate becomes excessive, a problem arises in that the amount of sludge to be treated increases, and there is a drawback that stable operation cannot be performed.

In order to eliminate such drawbacks, it is conceivable to control the amount of chemical injection depending on the pH of the sludge.

In FIG. 2 showing an example of the 17'C chemical injection amount control device, 19 is a chemical injection tank consisting of a ferric chloride injection tank 1 and a slaked lime supply tank 2, and 3 is an input sludge pipe. , 4 is a supply sludge pipe, 5 is a ferric chloride injection pipe, 6 is a slaked lime injection pipe, 11a, 11b are electric valves, 12 is a ferric chloride flow meter, 17 is a slaked lime flow meter, 18 is a stirring It is a device. These elements are equivalent to those shown in FIG.

7 and 13 are 2" pH meters installed in ferric chloride injection tank 1 and slaked lime injection tank 2, 10 and 16
is a manual setting device. 8 is the pH for ferric chloride injection tank 1
The input is the signal from the pI-1 manual setting device 10, and the output is connected to the injection amount controller 9. -F*14 is the signal for the slaked lime injection tank 2. With a pH controller,
A signal from the pH remover 13 and manual setting device 16 is input, and its output is connected to the injection amount controller 15.The operation will be explained next. In fig.

The amount of ferric chloride injected is controlled by adjusting the OpH value in the ferric chloride injection tank 1 to the open side of pHHI3, and the fc value to 3.5 to 5.5.
The pH is compared with the preset n'rc
The electric valve 11 is adjusted according to the difference between n and -'t by the controller 8.
The goal is to adjust a.

QFe=G1(pH1-pH1”) =-(a+
Here, pH □: Ferric chloride injection tank pH @ pH 1": Ferric chloride injection tank pH setting system G □: Gain of pH adjustment 8 Ferric chloride injection tank pH setting Tsukuda (p) 11") is 1 Set using the manual setting device 10. Ferric chloride injection amount (QF
e) is obtained from the output of the pH controller 8, and is the setting force of the ferric chloride injection amount controller 9.

In this controller 9, the signal from the ferric chloride flowmeter 7 and (
QF. ) is used to adjust the electric valve 11a.

The 1fc slaked lime injection amount is controlled by the pH in the slaked lime injection tank 2.
n, set in advance in the range of 11 to 12, for example.
7't pH Depending on the difference from the set price, the electric valve 16
It is achieved by adjusting the

QCa=G2 (pH2-pH2") ・ (41 where pH2: pH of the slaked lime injection tank (pH 2"): PH setting value of the slaked lime injection tank G2: Gain of pH controller 14 + 51 calculation of formula 41 is calculated using pH controller 14. The slaked lime injection tank pI (set price (pH 2) is set in the manual setting device 16, and the slaked lime inlet tank pH (pH 2) is set in the pH meter 1).
n is obtained as the output of 3. The amount of slaked lime injection (Qca) is
n obtained as the output of the pH controller 14.

The setting of the slaked lime injection amount controller 15 becomes a hermit force. In this controller 15, the signal from the slaked lime flow meter 12 and (Qaa)
The operation of adjusting the electric valve 11b is performed using the following.

Although the apparatus constructed in this manner does not have any disadvantages of the apparatus shown in FIG. It is inevitable that the chemical injection amount cannot be adjusted in time to sudden changes in the flow rate, concentration, etc. of the input sludge, resulting in an excess or deficiency in the amount of chemicals used, and the stability of sludge refining cannot be said to be sufficient.

The present invention was made in order to eliminate the above-mentioned disadvantages.1, the dry matter amount of sludge is calculated from the flow rate L and concentration of input sludge, and the 7'C ratio is calculated in proportion to this calculation unit. As the basic amount of iron or slaked lime injection amount.

It is important to modify this basic amount according to the phi of the sludge after chemical injection, so that even if there is a sudden change in the flow rate or concentration of the input sludge, there will be no excess or deficiency in the amount of chemicals used, and stable refining can be achieved at all times. The purpose of the present invention is to provide a chemical injection amount control device that has the following features.

An embodiment of the present invention will be described below with reference to the drawings. Third
In the figure, 19 is a chemical injection tank consisting of a ferric chloride injection tank 1 and a slaked lime injection tank 2, 3 is an input sludge pipe, 4 is a supply sludge pipe, 5 is a ferric chloride injection pipe, and 6 1 is a slaked lime injection pipe, lla and llb are electric valves, 12 is a ferric chloride flowmeter, 17 is a slaked lime flowmeter, and 18 is a stirring device.

and n et al. are equivalent to those shown in FIG.

7. 13 is an a*pn meter installed in the ferric chloride injection tank 1 and slaked lime injection tank 2, and 10. 16 is a manual setting device. 8 is a pH controller for the ferric chloride injection tank 1, which receives signals from the PHHI 3 and the manual setting device 10, and its output is connected to the injection amount controller 9. '
Ffc14 is a pH controller for the slaked lime injection tank 2, which receives signals from the pH meter 13 and manual setting device 16, and its output is connected to the injection amount controller 15.

Furthermore, 20 is a sludge flowmeter for feeding into the chemical injection tank 19, and 21
are input sludge concentration meters, both of which are installed in input sludge pipe line 3.
ing. Reference numeral 22 denotes a computing unit, which inputs signals from the input sludge flow meter 20 and the input sludge concentration meter 21. 23 Work 24
are ratio setters, both of which take the output of the arithmetic unit 22 as input. The output of one ratio setter 23 is connected to the input of the pH controller 8 for the ferric chloride injection tank 1, and the other ratio setter 2
The output of 4 is connected to the input of a pH controller 14 for the slaked lime injection tank 2.

Next, the operation will be explained. In fig.

The ferric chloride injection amount can be controlled using ferric chloride injection jlvJ1.
The basic amount is the amount proportional to the dry matter amount of sludge input.

In this step, the measured pH in the ferric chloride injection tank 1 (
For example, the nf is preset in the range of 4.5 to 5.5.
The effect is achieved by adding the amount corresponding to the cpH setting value and the setting button as the foot drop amount, and adjusting the electric pulp 11a based on this sum. Basic amount of ferric chloride injection amount (QFeF) Fi, expressed by the formula n.

QFeF=k −Qi −Ci −(51 where Qi: input sludge flow rate C1: input sludge concentration □: proportional constant In equation (5), input sludge concentration (Ci) and input sludge flow rate (Qi) are 7n n, (Qi
-Ci) In other words, the calculation of the amount of dry matter (the amount of solid matter) in the input sludge is performed by the computing unit 22. 'F7
t(kl) is a proportionality constant predetermined in the ratio setter 23, and the calculation on the right side of equation 51 is performed in the ratio setter 23. Therefore, the left side (QF, The n obtained as the output of the device 23 is the input to the pH controller 8.The amount of ferric chloride injected is (QF8F)
It was decided to add the amount of pH feedback of the ferric chloride injection tank 1.

QF6"'QF6F ten G3 (pHI PHI"F)
... (6) In equation (6), (G3) is the gain of pH controller 8, and the calculation of equation (6) is performed using pH controller 8.
It will be done in

The amount of slaked lime to be injected is controlled by setting the amount of sludge in proportion to the dry matter amount of sludge fed into the slaked lime injection tank 2 as a basic amount, and n to the measured pH in the slaked lime injection tank 2, for example, in the range of 11 to 12 in advance. This is achieved by adding an amount corresponding to the difference from the set pH value as a feedback amount, and adjusting the electric valve 11a'r based on this sum. The basic amount of slaked lime injection amount (Qcair) is expressed by the following formula.

Q(3a7=2@Qi-Ci-(71) where k2: proportionality constant In equation (7), the input sludge concentration (Ci) and the input sludge flow rate (Qi) are The calculation of n, (Qi-Ci) obtained as the input sludge 7M and the output signal of the indicator needle 21, in other words, the calculation of the dry matter amount (solid matter amount) in the input sludge, is performed by the computing unit 22.
Ru. 'Efc(k2) is a proportionality constant of 1 predetermined in the ratio setter 24, and the calculation on the right side of equation (5) is performed by the ratio setter 24. The left side (Qc,
r ) is obtained as the output of the ratio setter 24 and 1. This 1 becomes the input to the pH controller 14. The amount of slaked lime injected is (Qc
BF) and the feedback amount of the pH of the slaked lime injection tank 2.

Qaa=Qaay ten Gq (pH2-pH2') ・
...(8) In equation (8), (G,) is pH controller 8
The calculation of equation 5(8) is performed by the pH controller 14.

In the fC example shown in Fig. 3, the injection amount of ferric chloride and slaked lime was controlled according to the sludge dry matter amount and the pH feedback amount. The amount of slaked lime to be injected may be controlled only by the feedback amount of pH@.

It is also possible to use the injection amount of 1 fc ferric chloride as a reference, and use an amount proportional to this amount as the basic amount of slaked lime injection amount. A device constructed in this manner is shown in FIG. In FIG. 4, 25 is a ratio setter, to which the output of the ferric chloride injection meter 12 is connected as an input. The output of this ratio setting device 25 is connected as an input to the pH controller 14 for the slaked lime injection tank 2.

Furthermore, it is also possible to configure the system so that an amount corresponding to the output of the pH controller 8 for the ferric chloride injection tank 1 is used as the basic amount of slaked lime injection. A device constructed in this manner is shown in FIG. In FIG. 5, 25 is a ratio setter, to which the output of the pH controller 8 is connected as an input. The output of the ratio setter 25 is connected as an input to the pH controller 14 for the slaked lime injection tank 2.

In the above embodiment, the instrumentation circuit is constructed of a time-continuous analog type, but similar effects can be obtained with a time-discontinuous analog type (sampling type) or digital type instrumentation circuit.

As described above, the present invention has one advantage: it is proportional to the calculation unit of the input sludge dry matter amount, and the fc amount is the basic amount of the injection amount of ferric chloride = F or slaked lime, and the feedback amount of pH is set to this amount. In addition: One liter of ferric chloride was used to control the amount of slaked lime injected.

Even if the flow rate or concentration of the input sludge changes suddenly, there will be no excess or deficiency in the amount of chemicals injected, and there is always a stable refining ability.

[Brief explanation of the drawing]

1 and 2 are block diagrams showing the configuration of a chemical injection amount control device according to an embodiment of the present invention, and FIG. 3 is a block diagram showing the configuration of a chemical injection amount control device according to an embodiment of the present invention.
FIGS. 4 and 5 are block diagrams showing other embodiments of the present invention. 1...Second iron chloride injection tank, 2...Slaked lime injection pipe 3
...Input sludge pipe line, 4...Sludge supply pipe line, 5...
Ferric chloride injection pipe, 6... Slaked lime injection pipe, 7.1
3...pH meter, 8,14...-pE controller, 9.15
...Injection amount controller, 10, 16-...Manual setting device,
ll&, llb...Electric valve, 12.17...Flow meter, 19...Chemical injection tank, 20...Input sludge flow meter, 21...Input sludge concentration meter, 22...Arithmetic unit ,2
3.24...Ratio setter. In addition, the same or equivalent parts are shown in the figure. Agent (and 4 others) Figure 2

Claims (1)

[Claims] A chemical injection amount for controlling the injection amount of ferric chloride and slaked lime when sludge is tempered by injecting ferric chloride into Tl+ sludge and then injecting slaked lime. In the control device, there is a computing unit that calculates the input sludge dry matter amount from the flow rate and concentration of the input sludge, a first OpH word that measures the sludge OpH after ferric chloride injection, and an input sludge dry matter amount that is the output of the above computing unit. A ferric chloride injection amount journal section for controlling the injection amount of ferric chloride according to the p'Hi measured by the first p)1 meter, with an amount proportional to the amount as the basic amount; and a second pH meter that measures the pHff1 of the sludge after slaked lime is injected. The device is characterized by being equipped with a slaked lime injection amount regulator that compares the n'fcpH measured by the second PH meter with a predetermined fcpH setting and adjusts the slaked lime injection amount according to the difference. Chemical injection amount control device for sludge treatment equipment. (2) In a chemical injection amount control device for controlling the injection amount of ferric chloride and slaked lime when sludge is tempered by injecting ferric chloride into the sludge and then injecting slaked lime, A first pH meter is used to measure the pH of the sludge after ferric chloride is injected. A ferric chloride injection amount controller that adjusts the amount, and a calculator that calculates the dry matter amount of input sludge from the flow rate and concentration of input sludge. A second pH meter measures the pH range of sludge after slaked lime is injected, and the second OpH meter measures nfcpn using an amount proportional to the input sludge dry matter amount, which is the output of the arithmetic unit, as a basic amount.
A chemical injection amount control device for sludge treatment equipment, characterized in that it is equipped with a slaked lime injection amount control section (1) that controls the injection amount of slaked lime according to the amount of slaked lime.