SU1493677A1 - Method of automatic control of process of saturation of defecated juice in multisection saturator - Google Patents

Abstract

The invention relates to the automation of sugar production, in particular to the automatic control of the processing of defecated juice by saturation gas in a multi-compartment saturator of continuous action. The purpose of the invention is to reduce the loss of sugar by increasing the accuracy of regulating the pH of the juice. This is achieved by automatically searching for the optimal pH setpoint of the juice. When the quality of the diffusion juice changes, the nature of the curves for a multi-section saturator does not change, but only the absolute values of the parameters change. Structurally, the saturator is designed so that the extreme values of the parameters correspond to certain sections of the saturator, i.e. The second and third sections. The proposed method involves measuring the viscosity and PH discretely, at the outputs of the second and third sections of the saturator the maximum viscosity value is determined at the output of the second section of the saturator and the minimum value of the juice viscosity at the output of the third section of the saturator and set the zone the insensitivity of changes in the viscosity and pH increments of the juice, and the set values of the pH of the juice at the outputs of the second and third sections of the saturator are set respectively to the current values of the pH of the juice in these sections and dead zones and Changes in the viscosity and pH increments of the juice. 2 Il.

Description

the dead zone of changes in the viscosity increments and pH of the juice between the i-th and (1st) -th measurement control step at the experimental points and sets the set value for the juice at the outlet from the second section of the saturator equal to the current value at the maximum juice viscosity at the exit from the second section of the saturator, and for, the pH value of the juice at the exit from the third section of the saturator is set equal to the current value with the minimum viscosity at the exit from the third section of the saturator, and the maximum and minimum juice viscosity is determined by comparing the viscosity of juice at the output of these sections in the i-oM and (i-1) th measurement control steps

In addition, when the juice viscosity reaches its maximum at the outlet of the second section of the saturator, the pH increment of the juice at the output of the same section of the saturator is determined, compared to the specified value of the dead zone of the juice pH for this section and, if the increment of the juice is zero or less, then the set value of the pH of the juice is set equal to the current value, and if more than zero, the set value of the pH of the juice does not change.

When the viscosity of the juice reaches its minimum at the exit from the third section, the pH increment of the juice at the exit from the same section of the saturator is determined, the pH value of the juice for this section is compared with the specified dead zone, and if the pH increment is equal to or less than zero, then the set pH value the juice does not change, and if it is greater than zero, the set pH value of the juice is set equal to the current pH value of the juice.

At the same time, the content of carbon dioxide in the saturation gas, the consumption of saturation gas, the consumption of defecated juice entering the apparatus, the pH of the juice at the outlet of the fourth section of the saturator are measured simultaneously and the consumption of the saturation gas is adjusted in the first two sections of the saturator by the ratio Defecated juice and carbon dioxide consumption with correction for the deviation from the set pH value of the juice at the outlet from the second section of the saturator and the rate of its change.

936774

The gas flow rate in the third section of the saturator is controlled by the deviation of the actual pH value of the juice from the set point at the outlet from the third section and the rate of its change.

The gas flow rate in the fourth section of the saturator is controlled by the deviation of the actual pH of the juice from the setpoint at the outlet of the fourth section and the rate of its change. The set pH of the juice at the exit of the fourth section of the saturator is set and maintained in accordance with the recommended procedure regulation instructions. by value

Fig. 1 shows the experimental curves of the optimal values of the parameters obtained on an experimental sample of a four-section saturator; FIG. 2 shows a block diagram of an apparatus for implementing the method „.

The nature of the saturation process in the optimal mode corresponds to the curve of the change in viscosity, pH and alkalinity of the filtered juice shown in Fig. K. At the same time, when the quality of the diffusion juice changes, the character of the curves for the multi-section 30 saturator does not change, but only the absolute values of the parameters about the Saturator are implemented in such a way that the extreme values of the parameters correspond to certain 35 sections of the saturator, Toe „the second and third section of Mo

The maximum viscosity of the juice at the outlet of the second section of the saturator reflects hydrophilic colloidal (gel)

a state of juice, in which, along with particles of the dispersed phase (small crystals of calcium carbonate), coherent sucrose and calcium hydroxide are present, as well as free hydroxide

calcium about

Further saturation (one third section) results in the binding of free calcium hydroxide and hydrophilic carbonaceous saharath to calcium carbonate, the adsorbed OH ions are neutralized by CO and the gel disintegrates, freeing sucrose and calcium carbonate on structural changes in the solution gives information

juice viscosity, reaching a minimum and, at the same time, juice pH, reaching a maximum „

In the fourth section, calcium carbonate crystallizes and

tori (and pH) are also entered from the operator’s panel 8 into the device memory

51

enlargement of particles of sediment of juice I saturation; the alkalinity and pH of the juice is reduced to the specified optimal values,

In figs, points a, b, c correspond to optimal pH values of the juice, alkalinity of the filtered juice and viscosity at the outlet of the second section, points d, e, f are at the outlet of the third section, respectively; points g, h, i - respectively at the exit of the fourth section of the saturator

The method of automatic control of the carbonation process of the juice is carried out as follows. At the output of the second section of the multisection saturator 1, the viscosity of the juice is measured by viscometer. flow rate of gas saturation by sensor 5 and flow rate of juice passing through a slit flow meter, sensor 6 o Output current signals, proportional to the values of measured parameters, t to the inputs of the microprocessor control device 7, where they are converted into digital codes and processed. From the operator panel 8, the set values of the viscosity pH of the juice, the pH at the outlet of the second section of the saturator (at the first start of the system), the set deadband value of pH wyusode from the second zone satura

In the microprocessor control device 7, in the first step of polling the sensors, the input signals from the object come from the pH ;, viscosity 2 ;, the CO-C content; , consumption of domestic gas, consumption of diffusion juice, extinguished, o At the same time, the pH values are assigned to the index of the (i-i) -th step, i.e.

(; -i) This information in the microprocessor device 7 is processed (scaled, smoothed) and a control action is generated using the formula

fU2; m.

+ k, (pH; -. ,,) + X

ra. k, k j. m ,. with C, +

d (pH; -. ,,)

dtT

(I)

where is juice consumption in i-step; mji - gas consumption in i-step; the content of COj in the gas in the i-OM mare;

ratio;

- coefficient of proportionality;

with; - k, k

15 k,

s

0

PH

PH; - 3

2 (; - i)

k, Tg

5 4,

where S is the range of proportionality of the regulator; the current pH value in the i-th step;

set pH in (i-i) -th step; - lead time (differentiation);

- scaling factors.

The output signal proportional to the control action is converted into an analogue signal of the current and fed to the input of an electropneumatic transducer 9, the output signal of which controls the gas supply valve 10 to the first and second sections of the saturator.

On the control effect nakla5

give a restriction:

  Oh if g p, by

In the next polling step, the values

0

pH 5 / t 1 parameters

pH

h;

1, C, Sh; , t, -; ,

assign the value of S; 1ga (i-I) and entered into the memory of the microprocessor device in the form of an addressable data array

pH2 (: -,) 2 (; -.) (-l

  P

(; -.) i (-il m

c (; - i)

In the i-M polling step, an automatic mode compares the viscosity values of the juice at the output of the second section (current and specified or in the i-OM and (i-1) th survey steps).

If (-g; - 2U;., Nut the current and set value of the pH of the juice at the outlet of the second section of the saturator 1 (g is the dead zone

viscosity tolerance, for example & tl% of measuring range).

If (-.,) - | Д, /,

then the given value. pH., | remains unchanged (and is the zone of insensitivity to changes in pH, for example, L 0.04 pH%).

If (- P ,. -) then the pH setpoint does not change. FROM 1

If (- pHff;.,) X-

r "then the set value of pH i, - s) is

nitts will be equal to pHg, and in the dataset it will be assigned the index of the (i-1) -th step.

If (2j; - 2 (, then the given value of i l becomes 2 | h in the data array, it is assigned the index (i-l) -ro tag

If (f; - 2 y., Then

the value of -jG-O is changed

Thus, in order to change the target pH value (, l, needed (

Observance of conditions

2d; .)) (pH2; -pH, J ,,, P, l. (3)

For example, for the data: 2i (;. ,, 0,305; 2 0,01; pHjj

 10.5; pH, Vo JO.51; La 0.04.

. Determine (i (0,3-0,305) 0,01; - 0,005 0,01, then compare (pH; - pH |.,)

-1- / D / or 10.5-10, 0.04;

l and

-0,, 02, then pH2 (;., 10.51,

those. does not change, because below the dead zone

If at pH il 10.6, and pH (; - i)

 10.55, then (10.6 - 10.55) -i- 1

X 0.04; 0.05 0.02, then pH | 3.

 10.55, Tov. will not change. If at pH; 10.5, and pH2 (;.,)

- 10.55, then (10.5 - 10.55): - | -x

X O 004, t „e„ -0.05 - 0.02, then (i-i) becomes equal to

10.5 pH, i.e. (1-0

If at pH

g

 10.5,

soz

 10.48, then (10.5 - 10.48) l- х

hh x 0.04, i.e. 0.02 0.02 and pH G,

 10.48. -

Thus, the set value of the pH of the juice will change if the condition of maximum viscosity and the pH of the juice below the set, Tce „

(z;,)) (ph,:,;.,), /}. ha

If (- fii; -,)) 2, then assign the index (il) -th tag to the current viscosity value and in the new step make a new comparison until the sign changes, which indicates that the maximum viscosity reached and you can adjust the set pH value of the juice „

At the same time, at the output of the third section of the saturator 1, the sensor 11 measures the viscosity of the juice, and the sensor 12 measures the pH of the juice. From panel 8 operator

l

enter the specified values of rIL; .l

ka and viscosity /, .. at the output of v ü 7 (1 -I;

the third section of the saturator These values are assigned the index of the (i-l) -th step

When the microprocessor device automatically switches over to this mode, in the first step of polling the sensors, signals from sensors 11, 12 are received, which are proportional to the pH values and viscosity; "This information is processed (scaled, smoothed, and a microprocessor-controlled device 7 is controlled by the PID control law," The control effect is superimposed, if the flow rate is zero, the valve 13 is closed

Thus, the controlling effect on the gas supply to the third section of the saturator is proportional to the pH deviation, in the i-th tag from

in the (i-l) th step and its rate of change.

The control action is formed in a microprocessor device in the form of a corresponding current signal input to the input of an electropneumatic transducer 14, the pneumatic output of which controls the gas supply valve 13 to the third section of the saturator.

In this case, the set value of pH j; ,,

at the output of the third section of the saturator 1, the viscosity of the juice at the outlet of the third section is determined.

If (2 ,; -iy.), L, then

compare the current value and the target pH value of the juice at the outlet of the third section of the saturator ({dead zone of the viscosity deviation of the juice at the exit of the third section, is, for example, 0.1% of the measuring range, determined experimentally)

If (pH, - pHjf ;,) b- - / Л5 /,

then the set pH value .; ,) remains unchanged (L is the dead zone of pH change at the outlet of the third section of the saturator, for example, Dz is 0.05 pH),

If (pH ;; -.)) Then the pH set,; -,) changes and becomes equal to pHz, and in the dataset it will be assigned the index (l-l) -ro of the step

(pH ;; pH

- 11.75) ---- 0.05

ten

15

20

25

thirty

(0.02 0.01) A (0.05 0.025). In this case, the current value of pI,; the index of the (i-l) -th tag is assigned,. for the next step of the comparison, we will have a PH, a (;., 11.8,

If 1 1.8 and pH,;., 12.0, then (11.8 - 12.0) - | - X

X 0.05; -0,, 025 and the set value .i) b will change;,

If 11.8, a.,) 11.83, then at (11.8 - 11.83):: -p-D e we have a -0.03 -0.025 the given pH value (,) does not change.

At the exit from the third section of the saturator, the pH of the juice will have a maximum value corresponding to point d of curve I, FIG.

At the output of the fourth section of the saturator, pH 4 is measured, the juice of the sensor 15 with the converter, the output signal of which is fed to the input of the microprocessor device, where it is processed (converted.

If a

scaled, smoothed).

Set value ,, juice

at the exit from the fourth section of the saturator, the operator enters from the panel 8.,) iМ} /, 35 of the control. This value is set to% 9 X. one

P

this set pH value /;.,) does not change.

If (,; -,)) 3, then

and 59

the given value of sb-o anethe equal to f}, and in the database array it is assigned the step index (i-l) -ro, i

So that changed

l

pH value, l

(;) s L (pHz; - -RNY.m)

40

(four)

It depends on the technological regulations when processing beets of different quality and technological scheme of the plant.

According to the information received, the microprocessor control device 7. Forms the control action in the form of a standard current signal varying in the PDC-law. 45 This control is applied to the input of the electropneumatic transducer 16, the output pneumatic signal of which controls the actuator of the control valve 17. gas in the fourth section of the saturator ",

This method also provides for the stabilization of the saturation gas pressure in the receiver 18. Lavle50

For example, for data:; 0.20;

MiM) v o. ph;

 11.8; . ,, 11,75; L, 0.05; By the condition (4) we have:

(0.2 - 0.18) 0, oQ L (11.8 - 11.75) ---- 0.05

(0.02 0.01) A (0.05 0.025). In this case, the current value of pI,; the index of the (i-l) -th tag is assigned,. for the next comparison step we will have a PH, a (;., 11.8,

If 1 1.8 and pH,;., 12.0, then (11.8 - 12.0) - | - X

X 0.05; -0,, 025 and the set value .i) b will change;,

If 11.8, a.,) 11.83, then at (11.8 - 11.83):: -p-D e we have a -0.03 -0.025 the given pH value (,) does not change.

At the exit from the third section of the saturator, the pH of the juice will have a maximum value corresponding to point d of curve I, FIG.

At the output of the fourth section of the saturator, pH 4 is measured, the juice of the sensor 15 with the converter, the output signal of which is fed to the input of the microprocessor device, where it is processed (converted.

scaled, smoothed).

at

40

)

;

,

depends on the technological regulations in the processing of beets of different quality and technological scheme of the plant.

According to the information received, the microprocessor control device 7. Generates a control action in the form of a standard current signal varying in the PDC-law45. gas in the fourth section of the saturator ",

This method also provides for the stabilization of the saturation gas pressure in the receiver 18. Gas beauty is measured by the sensor 19, the output current signal of which is proportional to the gas pressure arrives at the input of the microprocessor device 7, where

eleven

1493677

into a digital code, smoothed, the measurement limit is massaged), and a control signal is generated in the form of a current that varies in accordance with the pi-law of regulation. The setpoint pressure in the receiver is entered by the operator from the microprocessor control panel 8.

The output signal of the current is fed to the input of an electropneumatic transducer 20, the pneumatic signal of which controls the regulating valve 21 for the discharge of the saturation gas into the atmosphere

The microprocessor control device 7, in addition to the control panel 8, includes a display 22 for input-output data of process parameters, coefficients and settings, as well as a panel 23 for selecting the operating mode of control loops (automatic or remote).

Using this method of automatically controlling the saturation process of diffusion juice in a multisection saturator makes it possible to form the specified pH values of the juice at the output of the second and third sections of the saturator in automatic mode of juice viscosity, which characterizes the structural changes in juice when it is treated with saturation Hbw gas. The specified pH values of the juice in the sections correspond to the optimal values at which the maximum effect of juice cleaning is ensured, which makes it possible to improve the quality of the juice and reduce sugar losses: the quality of the purified juice was 0.4 units, the cleaning effect was 2.2 - 3.0%, chromaticity and the content of calcium salts are reduced by 5-10%. In this method, the level of automation of the juice purification process is increased, since the number of manual operations is reduced.

I 2

The formula of the invention. A method for automatically controlling the carbonation process of defecated juice in a multisection saturator, which involves measuring the carbon dioxide content of the saturation gas, the consumption of saturation gas and decocitated juice, the pH of the juice at the outputs of the second, third and fourth sections of the saturator, controlling the gas flow in the first two sections a saturator with respect to the costs of defecated juice and carbon dioxide with a correction for the deviation from the given pH value of the juice at the outlet of the second section of the saturator and correction of gas flow to the third section by the deviation of the actual pH value of the juice from the target and its rate of change at the outlet of the second section of the saturator, correction of the gas supply to the fourth section by the sum of the deviations of the actual pH of the juice from the target and the rates of pH change of the juice output from the second and third sections of the saturator, characterized in that, in order to reduce sugar losses by increasing the accuracy of adjusting the pH of the juice, the viscosity of the juice is measured at the outputs of the second and third sections of the saturator, Volume measurement of viscosity and pH is carried out discretely, the maximum value of juice viscosity at the outlet of the second section of the saturator and the minimum value of juice viscosity at the outlet of the third section of the saturator are determined by comparing the values of juice viscosity in i-OM and (i - 1 ) th measurement steps, set the insensitivity zone of changes in viscosity increments and pH of juice between 1–1 m and (i - 1) th measurement control steps; pH of juice in these sections, taking into account the extreme values of juice viscosity.

P .

11 0.2

YU

I F F W Section

cmi9ypamopa

Фа9.1

at

 f t 1 g

I

Gas

L

y27

23

1

Claims (1)

SUMMARY OF THE INVENTION A method for automatically controlling the process of saturation of defecated juice in a multi-section saturator, which measures the content of carbon dioxide in saturation gas, consumption of saturation gas and defecated juice, pH of juice at the outputs of the second, third and fourth sections of the saturator, regulation of gas flow in the first two sections of the saturator in relation to the flow rates of the defecated juice and carbon dioxide with correction for deviation from the preset pH value of the juice at the outlet of the second section of the saturator and speed its changes, correction of the gas flow to the third section by the deviation of the actual pH of the juice from the set and the rate of change at the outlet of the second section of the saturator, correction of the gas supply to the fourth section by the sum of the deviations of the actual pH of the juice from the set and the rates of pH of the juice by exit from the second and third sections of the saturator, characterized in that, in order to reduce sugar loss by increasing the accuracy of pH adjustment of the juice, measure the viscosity of the juices at the outputs of the second and third sections of the saturator, with this measure the viscosity and pH are carried out discretely, the maximum value of the viscosity of the juice at the outlet of the second section of the saturator is determined and the minimum of the viscosity of the juice at the outlet of the third section of the saturator by comparing the values of the viscosity of the juice in the i-th and (i - 1) -th measurement steps, the dead zone of changes in viscosity increments and pH of the juice between the i-th and (i - 1) -th steps of the measurement control, and the set values of the pH of the juice at the outlet of the second and third sections of the saturator are set equal to the current pH values of the juice in these sections, taking into account extreme values juice viscosity index. spayaurator Fi8.1 Figure 1