JPH0779720B2 - Sugar liquid flow rate setting method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to an improvement in a method of setting a sugar solution treatment amount in a cleaning process in a sugar factory.

<Prior Art> An example of the prior art will be described with reference to FIG. Reference numeral 1 is a magma mixer, and 2 is a sugar washing separator that cuts out raw sugar in the magma mixer into a low liquor tank 3. W and R are sweet water and redissolved sugar solution supplied to the low liquor tank 3.

4 is the level sensor of the low liquor tank, PV ₁ is the measured value. 5 is a level controller, measured value PV
The level of the low liquor tank is controlled to the set value by operating the sugar wash separator 2 with the operation output MV ₁ that controls and calculates the deviation between ₁ and the set value SV ₁ .

The sugar solution output from the low liquor tank is the first flow rate control means.
Guided by C ₁ . In this flow rate control means C ₁ , 6 is a flow rate sensor, PV ₂ is its measured value, 7 is a control valve, 8 is a flow rate controller, and an operation output that controls and calculates the deviation between the measured value PV ₂ and the set value SV _2. MV ₂ is supplied to the control valve 7. Reference numeral 9 is a setting means for supplying the set value SV ₂ of the sugar liquid flow rate.

The sugar solution output from the first flow rate control means is introduced into the satiety solution tank 11 after the saturation process is executed after passing through the carbonate satiety tank 10 after the lime milk is added. 12 is the level sensor of the saturable liquid tank, and PV ₃ is its measured value. Reference numeral 13 is a level controller, which is a controller of the second flow rate control means C ₂ in which the operation output MV ₃ obtained by controlling and calculating the deviation between the measured value PV ₃ and the set value SV ₃ is introduced to the sugar solution output from the saturable liquid tank. Is supplied as a cascade setting value SV ₄ .

In the second flow rate control means C ₂ , 14 is a flow rate sensor PV ₄
Is a measured value, 15 is a control valve, 16 is a flow controller, and the operation output MV ₄ that controls and calculates the deviation between the measured value PV ₄ and the cascade setting value SV ₄ is supplied to the control valve 15 to adjust the flow rate. , Adjust the level of the saturable liquid tank 11 to the set value SV ₃ .

The sugar solution output from the second flow rate adjusting means passes through the primary filter 17 and is guided to the brown liquor tank 18. 19 is the level sensor of the brown liquor tank, PV ₅ is its measured value, 20
Is a level controller, which is a controller of the third flow rate control means C ₃ for controlling the flow rate of the sugar solution output from the brown liquor tank using the operation output MV ₅ that controls and calculates the deviation between the measured value PV ₅ and the set value SV _5. Is supplied as a cascade setting value SV ₆ .

In the third flow rate control means C ₃ , 21 is a flow rate sensor PV ₆
Is a measured value, 22 is a control valve, and 23 is a flow rate controller.The operation output MV ₆ that controls and calculates the deviation between the measured value PV ₆ and the cascade setting value SV ₆ is supplied to the control valve 22 to adjust the flow rate. , Adjust the level of the brown liquor tank 18 to the set value SV ₅ .

The sugar solution output from the third flow rate control means C ₃ passes through the bone charcoal adsorption tower 23 for decolorization and is guided to the decoloring tank 24.

Further, the sugar solution output from the decoloring tank is sent to the crystallization step through a processing step such as a ceramic filter means, an ion exchange resin tower, and a condensing can as necessary.

Each element of each process described above may be called by another name by the factory.

<Problems to be Solved by the Invention> Such a control system is basically a cascade connection of the level control systems of the respective tanks, and the processing sugar solution flow rate setting is the first.
It is carried out by changing the set value of the setter 9 in the flow rate control means C _{1, and} changes in the flow rate measurement value PV ₂ of the first flow rate control means are given to the level controller 13 of the next stage via the dead time correction circuit 25 and operated. Correct the output, and then measure the flow rate PV of the second flow rate control means.
The change of ₄ is given to the level controller 23 of the next stage through the dead time correction circuit 26 to correct the operation output, and further the change of the flow rate measured value PV ₆ of the third flow rate control means is passed through the dead time correction circuit 27. This is a setting method for correcting the operation output by giving it to the level controller in the next process.

In the case of such a configuration, when the operation of changing the amount of sugar solution is executed,
Since the flow rate control means on the downstream side is changed by a change in the measured value on the upstream side, if the measured value on the upstream side fluctuates due to some disturbance, there is a problem that all the flow rate on the downstream side fluctuates. This problem is the same in the steps after the decoloring tank.

An object of the present invention is to provide a flow rate setting method capable of solving such a problem.

<Means for Solving Problems> The structural feature of the present invention is that the sugar solution output from the low liquor tank is guided to the saturated liquid tank via the first flow rate control means and the carbonic acid saturation processing means, and this tank is In the sugar solution flow rate control device having a structure in which the output of the tank is guided to the brown liquor tank through the second flow rate control means and the primary filter means, and the output of this tank is sent to the next step through the third flow rate control means. The point is that the set value of the liquid flow rate is simultaneously supplied in parallel to at least the first to third flow rate control means.

<Operation> According to the present invention, the set value of the sugar liquid flow rate is simultaneously supplied in parallel to the first to third flow rate control means.

<Example> An example of the present invention will be described with reference to FIG. The same components as those described with reference to FIG. 2 are designated by the same reference numerals, and the description thereof will be omitted.

28 is the flow rate set value SV in the flow rate controller 8 of the first flow rate control means C _1.
First selector for supplying ₂ and 29 for second flow rate control means C ₂
Is a second selector for supplying the flow rate setting value SV ₂ to the flow rate controller 16, and 30 is a third selector for supplying the flow rate setting value SV ₃ to the flow rate controller 23 of the third flow rate control means C ₃ .

Reference numeral 31 is a means for setting the amount of dissolved sugar, and sets the amount of sugar to be treated by weight. Reference numeral 32 denotes a capacity conversion means, which converts the weight set value W _s into the flow rate set value F _s .

33 is a summing means, transmits the flow rate set value F _o by adding the flow rate set value PV _R of the return sugar solution R to low liquor tank to the flow rate setting value F _s.

34, 35, 36 are the 1st, 2nd, 3rd which inputs the flow rate set value F _o in common
It is a brix correcting means, and the first flow rate set value F _c1 and the second flow rate set value are obtained by multiplying F _o by the brix measured value BX.
F _c2 and 3rd flow rate set value F _c3 are respectively set to the 1st, 2nd and 3rd selectors.
Send to 28,29,30. In normal operation, these selectors have the above first flow rate setting value F _c1 , second flow rate setting value F _c2 , and third flow rate setting value F _c2 .
The flow rate set value F _c3 is selected and supplied to the first flow rate control means C ₁ , the second flow rate control means C ₂ , and the first flow rate control means C ₃ , respectively.

With such a configuration, the set value of the amount of sugar dissolved is simultaneously and parallelly supplied to the first flow rate control means C ₁ , the second flow rate control means C ₂ , and the first flow rate control means C ₃ .

Next, other input signals of the selectors 28, 29, 30 will be described.

In addition to the set value F _c1 , the selector 28 has a level measured value PV ₁ of the low liquor tank 3 and an output PV ₃ ′ of the function calculation means 37.
Is input and the minimum signal of the three is the set value SV ₂
Is selected as. The function calculation means 37 has a characteristic that the measured value PV ₃ of the level sensor 12 of the saturable liquid tank is input, and the output is lowered when PV ₃ approaches 100%.

Therefore, the selector 28 selects PV ₁ or PV ₃ ′ when the level of the low liquor tank 3 falls below a certain value or when there is a risk of overflow of the saturated liquid tank 11, respectively, and selects the cascade set value SV of the flow rate. _It has the function to be ₁ .

In addition to the set value F _c2 , the selector 29 is input with the level measured value PV ₃ of the saturable liquid tank 11 and the output PV ₅ ′ of the function calculating means 38, and the minimum signal of the three is the set value SV ₄ Is selected as. The function calculation means 38 inputs the measured value PV ₅ of the level sensor 19 of the brown liquor tank, and PV ₅ is 100%.
It has the characteristic of decreasing its output when it approaches.

Therefore, the selector 29 selects PV ₃ or PV ₅ ′ when the level of the saturated liquid tank 11 drops below a certain value or when there is a risk of overflow of the brown liquor tank 18, respectively, and selects the cascade set value SV of the flow rate. _It has the function of ₄ .

In addition to the set value F _c3 , the selector 30 receives the level measurement value PV ₅ of the brown liquor tank 18 and the output PV ₇ ′ of the function calculating means (not shown) of the next step, The minimum signal of is selected as the set value SV ₆ . The function calculating means in the next stage has a characteristic that the measured value PV ₇ of the level sensor of the tank in the next stage is input, and the output is reduced when PV ₇ approaches 100%.

Therefore, when the level of the brown liquor tank 18 drops below a certain level or when there is a risk of overflow of the tank in the next stage process, the selector 29 respectively sets PV ₅ or PV ₇ ′.
Has the function of selecting the flow rate cascade setting value SV ₆ .

With such a configuration, normally, the flow rate control based on the set value of the sugar liquid amount is executed in at least the first to third flow rate control means, and when the tank level in the preceding stage of each flow rate control means is lowered or each control means is controlled. When there is a risk of overflowing the tank level of the next stage, the cascade control is automatically switched to the measured value related to the tank level to prevent the tank from short-circuiting or overflowing.

<Effects of the Invention> As described above, according to the present invention, since the set value of the sugar liquid amount is given to each flow rate control means at the same time, the flow rate set value does not fluctuate due to the flow rate fluctuation in the preceding step. Since it is possible to follow the request for changing the throughput in the next step in a short time, stable operation becomes possible.

Further, since the tank is used as a buffer, it is possible to realize control in which the flow rate does not fluctuate even if the tank level fluctuates to some extent.

By such effect, to stabilize the P _H control in step, can of improving the efficiency of the filter, it is possible to improve the operating efficiency of the entire cleaning process.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 2 is a block diagram showing an example of a conventional technique. 1 ... Magma mixer, 2 ... Sugar wash separator, 3 ... Low liquor tank, 4, 12, 19 ... Level sensor, 5 ... Level controller,
6,14,21… Flow sensor, 7,15,22… Control valve, 8,16,23…
Flow controller, 10… Carbonate filling tank, 11… Carbonate filling tank, 17
… Primary filter, 18… Brown liquor tank, 23… Bone charcoal adsorption tower, 24… Decoloring tank, 28, 29, 30… Selector,
31 ... Sugar amount setting means, 32 ... Solution conversion means, 33 ... Addition means, 34, 35, 36 ... Brix correction means, C ₁ , C ₂ , C ₃ ... First,
Second and third flow rate control means

Claims (1)

[Claims] 1. An output sugar solution of a low liquor tank is led to a saturable liquid tank via a first flow rate control means and a carbonic acid satiety processing means, and the output of this tank is supplied to a second flow rate control means and a primary filter means. In the sugar liquid flow rate control device configured to lead to the brown liquor tank via the third liquid flow rate control means and to send the output of the tank to the next step via the third flow rate control means, the set value of the sugar liquid flow rate is at least the first to third flow rates. A sugar solution flow rate setting method characterized in that it is supplied to control means simultaneously in parallel.