SU787475A1 - Method of automatic control of sugar massecuite concentration process - Google Patents

Description

The invention relates to the sugar industry, namely to the automation of vacuum apparatuses of periodic effect. There is a known method for controlling the cooking process of the massecuite in a vacuum apparatus, which consists in determining the ratio of the structural viscosity of the product and its level during the cooking process, which changes after the crystals are charged, and programmed control of pumping of the syrup, which is carried out after the first deep pumping is completed first until a given final viscosity value is reached (while maintaining the level below the nominal value, and when the specified final viscosity is reached, syrup is pumped to the nominal level ). Sh. The disadvantages of this method are the need to frequently perform control cooking to determine the programmed values of the monitored parameter when the quality of the solution changes and the presence of a significant number of manual operations. Closest to the invention is a method for automatically controlling the process of boiling sugar fillings, which includes determining the moment of introduction of seed into the apparatus, controlling the level and absolute pressure, and measuring the electrical resistance in apparatus 2j. The disadvantages of this method of automatically controlling the process of boiling sugar buns are the instability of the process of crystal formation with fluctuations of good quality and the content of dry substances in the initial solution, which leads to the need to re-enter the crystals or melt their excess, reduce the quality of sugar and the productivity of the apparatus; manual control of the process at the stage of crystal formation and consolidation of the crystals, which leads to the rupture of the automatic control in the cooking cycle; programming of the process in relative values of parameters, which creates inconvenience in training and the work of operators; low process control accuracy. The purpose of the invention is to improve the quality of the sugar produced. This goal is achieved by setting the specified values

the electrical resistivity of the solution when charging crystals depending on the good quality of the initial solution with regard to its temperature, as well as setting a predetermined value of the electrical resistance of the solution at the beginning and end of the first pumping of the solution and at the crystal growth stage depending on the value of the electrical resistivity of the solution during charging the massecuite in the apparatus, set according to the good quality of the initial solution, is carried out by impulse regulation of the consistency of the massecuite; The value of which is determined by the level of the baffle in the apparatus, taking into account the good quality of the initial solution, while with a given set and actual value of electrical resistance at the beginning of the first pumping of the solution after entering the seed, the absolute pressure in the apparatus is determined and the time of operation at this pressure is determined by the level of masonry in the apparatus .

In addition, a value is established to which the absolute pressure in the apparatus is increased, depending on the good quality, and the content of solids in the solution being crystallized.

The proposed method is celebrated as follows.

For each value of db of the initial solution, the rational values of the coefficient of supersaturation are established for winding crystals. For example, for a syrup with DB, 92.5% sets the supersaturation coefficient to 1.25. This supersaturation value corresponds to a solution resistivity of R 320 ohms at, for a sugar solution with dB 82.5%, the supersaturation when crystals are charged is 1.36, which corresponds to the value of electrical resistance R 240 ohms, and for a solution with dB, 78% supersaturation when crystals are fed will be 1 , 4, the corresponding value of electrical resistance will be R 220 Ohms. These electrical resistivity values are set at (353 k). If the temperature changes, then these values are adjusted at the rate of 3 ohms per IC. (The value of the electrical resistance is set as in the prototype).

Crystals are charged by increasing the supersaturation after entering the seed without pumping the solution. The supersaturation is increased, for example, by 0.075; 0.085; 0.1 respectively for massecuites 1.11, crystallization. The value of the electrical resistance is programmed from the relation R 1.15R, where R is the value of the electrical resistance at the beginning of the first swap. Ohm After the crystals are charged, it is necessary to quickly reduce the supersaturation to a value of 1.0. Taking into account the non-uniformity of the temperature field in the apparatus and the presence of overshoot in process control systems, this value is set to 1.031, 05, depending on the design and capacity of the apparatus. In this case, the following changes in electrical resistance are programmed from the ratios

    . : crystallization

ZK

R

 0.5R

U crystallization

R

, "0, P) crystallization,

wvn where R- are the electrical resistance values corresponding to the end of the solution pumping. Ohm

After the formation of crystals, simultaneously with the pumping of the solution, the absolute pressure in the apparatus is increased. In this case, the magnitude of the increase in the absolute pressure is established depending on the good quality and the content of solids in the solution being crystallized. The period of operation at elevated absolute pressure is set depending on these parameters. For example, the given values of the increase in the absolute pressure from the flowing value and the value of the level of massecuite, to which the process is carried out at elevated pressure, are set to such

P

PH 1.1

0.04

1.15 0.08 1.1 hH 0.1 1.18 h. 0.12

natural solution,%;

SV - the content of dry substances in the initial solution (%); an increase in the absolute pressure in the apparatus, kg / cm; value of the level to which

Others operate at elevated absolute pressure;

-N is the level value of the initial set of the apparatus.

At. this is done by fixing the crystals formed.

After the cessation of crystal formation, conditions are created under which the crystals formed grow without the appearance of new crystals or the melting of existing ones. For this, taking into account the design features of the apparatuses, for example, the following supersaturation values are established with crystal growth

P 1.1 T crystallization P 1,13 3 crystallization P 1,15 jTi crystallization These values set the corresponding values of electrical resistances from the ratios

Claims (1)

Rjj 0.1 R 1 crystallization R-J, 0.6R 5l crystallization R, j 0.55 R U crystallization where Ri, ii., Yinz.v. - values of electrical resistance tia of the growth stage of crystals, Ohm. In this way, the programmed changes in the electrical contractions at these stages are carried out, in the final hundred of the process, based on the experimental data, the program values of the consistency of the solution are established, corresponding to the average values in the metastability zone. This takes into account the purity of the solution. The amplitude of deviation of the consistency of the fillet from the specified value is established, for example, from the ratios V, .c l08n,., T-min. 092rbj if 90 dB 94 "b. V.jiH-. or 80 4 dB: 80 TjMOllc 1. The level of the massecuite at which the control is transferred to the control; the consistency of the massecuite is set to M ° 65 waKC if DB is 92.5% if DB is 82.5% Li 055b ,,, jp, if DB is 78.0% For other values these values are adjusted based on the increase in the level at which impulse pumping is carried out by 3% for each unit of goodness from the accepted values, and for a solution from DB, 78.0% - by 5% for each unit of goodness. The drawing shows a block diagram of the proposed method. The vacuum apparatus is equipped with sensors 1-5 according to absolute pressure, level of massecuite in the apparatus, consistency of massecuite, electrical resistance of massecuite, solution temperature, as well as actuators and regulators 6-8 on vacuum pipelines, heating steam, pumped solution, the introduction of seed into the apparatus 9. The device for controlling the process of boiling over the massecuite includes setting devices 10-14 levels of the initial set of the device, the value of electrical resistance and when winding crystals, at the beginning of the first pumping, at the end of the First pumping, with the growth of crystals, the unit 15 correcting electrical resistance for solution temperature, unit 16 forming a given consistency of the solution, switching blocks 17-24, switching relay 25-40, device 41 controlling and controlling regulators 42-46, setting knobs 47 and 48 with job control devices, time relay 49, electropneumatic converter 50 and signal lamps 51-56. The proposed method is carried out as follows. Using the remote control bodies, the apparatus is prepared for operation, after which the setting device 10 sets the preset value of the initial set of the apprata, which is controlled by the device 41 operating in the program mode. When this signal passes the relay 28 and 29 switching. The actual value of the solution level is measured by the sensor 2, the output of which is fed to the input of the device 41 through the switching relays 30 and 31. The signals of the specified and actual values of the solution level are fed to the input of the controller 42, the output of which is connected to the executive body 8 of the regulating valve through the switching relay 32-35. If the predetermined level is greater than the actual value, the valve of the regulator 8 is opened and the apparatus is filled with a solution to the predetermined level. At the same time, the outputs of the regulators 43 and 44 are turned off by means of relays 32 and 33. When the device is filled to the level of the upper tube sheet, the switching unit 18 generates a signal opening the regulator 7 (gate valve on the heating steam pipeline), after which the solution is thickened to crystals . The value of the electrical resistance at the crystal initialization is determined by the goodness base of the initial solution of the setting device 11 and corrected for the solution temperature with the help of block 15. In blocks 12-14, the program values of electrical resistance are formed. The inputs of these blocks are connected to the output of block 15. The actual value of the electrical resistivity is measured using an electrode sensor working in conjunction with the device. When the solution resistance reaches a predetermined value when switching crystals, switching unit 20, the input of which is connected to the outputs of electrical resistance correction unit 15 and sensor device 4, generates a signal at the output that controls relay 25, 30, 28, 32 switching and time relay 49. At the same time, the valve of the seed entry into the apparatus opens the last time for a set time. The moment of switching the program and the input of the seed signal lamps 52 and 55. At the same time, the output signal of the sensor 4 is connected to the input of the device 41, turn off the signal level sensor 2 and the output signal of the correction unit 15 by means of a relay 25 and connect the signal of the setting device 12. Signal signal of the initial level 10 The apparatus is switched off using a relay 28 and the output of the setting device 12 is connected to the input of the device 41 and the controller 43. The controller 42 is turned off on command of the unit 20 controlling the operation of the relay 32. At the same time, the actual electrical resistance of the solution the smaller the set and the increase in electrical resistance from the moment the seed is introduced until the start of the first swap pumping is carried out without a solution pod into the apparatus. Upon reaching the actual electrical resistance equal to the preset, at the time of the first swapping of the switching unit 21, a switching signal of the relay 26, connecting to the device 41 and the controller 43, generates the output of the sensor 13, and the relays 39 and 40 switch the absolute pressure patches 47 and 48. Absolute pressure is increased by a specified amount. When the actual electrical resistance of the solution becomes equal to the specified one, the switching unit 22 generates a switch relay 27 that connects the output of the inhibitor 14 to the input of the device 41 and the controller 43 and turns off the output of the regulator 13. The regulator 43 maintains the electrical resistance of the solution equal to the electrical resistance during crystal growth. When the apparatus is filled to the level indicated, the switching unit 17 generates a signal of the relay 39, which turns off the signal of the relay 40 and the output of the setpoint 48 is connected to the input of the regulator 45. The regulator 45 maintains the specified absolute pressure in the apparatus until the end of the cooking cycle. The signal lamp 51 signals the operator to end the operation at elevated pressure. The process control in the control of electrical resistance is carried out to a predetermined level of solution in the apparatus, established from the above relations. When the set level is reached, the switching unit 23 generates a signal, switching relay 33, which turns off controller 43 output and connects controller 44 to the actuator, as well as a signal from relay 29 to connect the output of the setpoint controller to the device 41 and controller 44 The output of the regulator 43 is turned off. At the same time, the output of the sensor 3 is connected to the input of the device 41 and the regulator 44 through the switching relay 31 controlled by the unit 23. From this moment on, the solution is pulsed. The specified consistency settings of the solution are determined by experienced cooking and are formed depending on the level of the solution in the apparatus using a nonlinear block 16. When the apparatus is filled, the switching block 24 generates a switch relay 34 that shuts off the output of the regulator 44 and connects to the actuator a power source . The shutter of the regulator 8 is closed. When the actual value of the consistency of the solution becomes equal to the preset, switching unit 24 connects the output of switching unit 19 to relays 37 and 38, which disconnect the outputs of switching unit 18 and controller 45 to the inputs of actuators 6 and 7, connect their input to the power source, close the dampers heating steam and vacuum. Vary is ready. The operator performs the descent of the massecuite. In the process, the breakdown of the vacuum is possible. In order to maintain the crystal with an increase in the absolute pressure to a predetermined value, the controller 46 generates a signal from the relay 35, which connects the power source to the actuator of the valve 8, which closes. The use of the proposed method for automatic control of the sugar crystallization process allows one to ensure the program control of the sugar crystallization process over the entire cycle by automatically generating the program values of the controlled parameter; increase the stability of crystal formation due to a more accurate determination of the supersaturation coefficient adjusted for j; o6poKa4ecTBeHHOCTH solution; to increase the productivity of devices by 6-8% due to the maintenance of the process according to the program without additional pumping of water or juice; reduce the color of sugar by 0.1 by reducing the cooking cycle and maintaining the process in a given mode; reduce the consumption of heating steam by 1.5-2.0% by weight of the massecuite by reducing the pumping of water and juice; improve the granulometric composition of sugar in the massecuite by increasing the control accuracy and programming, which reduces the massecuite planking cycle and increases the centrifuge productivity by 10-15%, expanding the possibilities of using the proposed method by using a sensor to measure consistency; to improve the working conditions of operators through more complete automation of the process. Claim 1. A method for automatically controlling the process of boiling sugar buns in a vacuum apparatus, including determining the moment of introduction of seed into the apparatus, controlling the level and absolute pressure, and measuring the electrical resistance in the apparatus, characterized in that, in order to improve the quality of the sugar, the set values are set the electrical resistivity of the solution when crystals are charged, depending on the good quality of the initial solution, taking into account its temperature, as well as value of the electrical resistance of the solution at the beginning and end of the first pumping of the solution and at the stage of crystal growth, depending on the value