RU2214457C1 - Method for controlling of process for preparing of milk of lime - Google Patents

Abstract

FIELD: sugar industry. SUBSTANCE: method involves feeding lime and liquid into slaking apparatus for producing of slaked lime; separating non-slaked particles and contaminants from slaked lime; adjusting rate of liquid consumed for slaking depending on lime weight and moisture content of resultant slaked lime; feeding slaked lime and liquid into repulper; determining weight of slaked lime by weighing thereof; calculating liquid fed into repulper on the basis of formula offered by applicant, with resultant data being taken into account. Liquid fed into repulper may be sugar-containing solution, and consumption of said solution is determined with saccharose concentration being taken into account. Method allows calcium hydroxide concentration in milk of lime to be stabilized. EFFECT: increased efficiency and improved quality of milk of lime. 2 cl, 1 dwg

Description

 The invention relates to methods for controlling the process of preparing milk of lime in the sugar industry.

 A known method of controlling the process of preparation of milk of lime, which includes the flow of lime and liquid into the extinguishing apparatus to produce fluff, the separation of unextinguished particles and impurities from it, the regulation of the flow rate of the quenching depending on the mass of the lime and the moisture content of the fluff, the latter and the fluid in the remover determination of the mass of the supplied fluff and the flow rate of the liquid into the repulpator (SU 1447849, С 13 D 3/00, 12.30.88).

 The disadvantages of this method are the low quality of milk of lime, because the stability of the concentration of calcium hydroxide in it is not ensured, since for correcting the flow of liquid into the repulpator, the mass of the fluff is determined by calculating the difference between the masses of lime and waste. In this case, the errors of two measurements are additively superimposed on the result and, in addition, the calculation does not take into account the mass loss of the fluff with the vapor-gas mixture exiting the extinguishing apparatus. In addition, if a sugar-containing solution is supplied to the repulpator, its concentration affects the concentration of calcium hydroxide in the milk of lime, but this effect is not taken into account. Therefore, in this case, there will also be a decrease in the stabilization accuracy of the set value of the concentration of calcium hydroxide in the milk of lime at the outlet of the repulpator.

 The technical result of the invention is to improve the quality of milk of lime and ensuring a stable concentration of calcium hydroxide in it.

где dm - масса жидкости, подаваемой в репульпатор, кг;

- расход жидкости в репульпатор, кг/ч;
К - корректировочный коэффициент;
dm_пуш. - масса пушонки, подаваемой в репульпатор, кг;

- расход пушонки в репульпатор, кг/ч;
В - влажность пушонки, %;
Р_зад.2 - заданная концентрация гидроксида кальция в известковом молоке, % СаО.The technical result is achieved by the fact that in the method of controlling the process of preparation of milk of lime, which provides for the supply of lime and liquid to the extinguishing apparatus to produce fluff, separation of non-quenched particles and impurities from it, controlling the flow rate of the quenching depending on the mass of lime and humidity of the resulting fluff, of the latter and the fluid in the repulpator and the determination of the mass of the feed fluff and the flow rate of the fluid in the repulpator, new is that the determination of the mass of the fluff is carried out by weighing it Ivanov and liquid flow supplied to repulpator calculated by the formula:

where dm is the mass of fluid supplied to the repulpator, kg;

- fluid flow rate to the repulpator, kg / h;
K is the correction factor;
dm _push. - mass of fluff fed to the repulpator, kg;

- consumption of fluff in the repulpator, kg / h;
In - moisture fluff,%;
P _{ass. 2} - the specified concentration of calcium hydroxide in milk of lime,% CaO.

 At the same time, if a sugar-containing solution is used as the liquid supplied to the repulpator, then its consumption is determined taking into account the concentration of sucrose in it.

 The invention is illustrated in the drawing, which shows a diagram for implementing the method.

 The scheme includes a hopper 1, a feeder 2 for feeding lime to a quenching apparatus 3, a sorting drum 4, a repulpator 5 for mixing fluff with liquid until milk of lime is produced, regulator 6, meter 7 of lime mass, actuator 8, regulator 9, flow meter 10, executive a mechanism 11, a driving device 12, a correcting device 13, a moisture sensor 14 for the fluff, a regulator 15, a flowmeter 16, an actuator 17, a driving device 18, a meter 19 for the weight of the fluff, a sucrose concentration sensor 20, a computing device 21, corrective device 22.

The following notation is used in the diagram: P _{assignment 1} - assignment for moisture of the fluff,%; P task ₂ - task on the concentration of calcium hydroxide in milk of lime,% CaO; P ₁ ÷ P ₁₁ - information signals between the elements of the control part of the circuit.

 The method is as follows.

 Lime from the hopper 1 is fed by a feeder 2 to a quenching apparatus 3. There, a quenching liquid is supplied, which enters into a hydration reaction with lime, resulting in a fluff (dry powder). In the sorting drum 4, solid extinction waste is separated from the fluff. From the extinguishing apparatus 3, the fluff is fed to the repulpator 5, in which it is mixed with the liquid until milk of lime is obtained.

The flow of lime into the extinguishing apparatus 3 is changed by the regulator 6 according to the readings of the meter 7 of the lime mass using the actuator 8, and the fluid flow rate is changed by the regulator 9 according to the readings of the flow meter 10 (signal P ₂ ) using the actuator 11. The task to the regulator 9 forms the setting device 12 in depending on the flow of lime, measured using a meter 7 of lime mass. This ensures the maintenance of the ratio of the flow rates of lime and liquid necessary for the implementation of the hydration reaction of lime and cover water losses due to evaporation in the extinguishing apparatus. The value of the ratio of the flow rates of lime and liquid supplied to the extinguishing apparatus 3, is adjusted by the device 13 according to the readings of the moisture sensor 14 of the fluff.

 The flow rate of the liquid to the repulpator 5 is changed by the regulator 15 according to the readings of the flow meter 16 using the actuator 17. The task to the regulator 15 forms a master device 18 in accordance with the existing functional relationship (calculated by the device 21) between the flow rate of the fluff measured by the fluff mass meter 19 and its humidity, measured by the moisture sensor 14 of the fluff.

For mixing with a fluff in the repulpator, it is advisable to use a sugar-containing solution (filter washes, saturated juices, etc.) in order to reduce or eliminate the dilution of the juice to be purified with excess water introduced along with milk of lime. In the case of using a sugar-containing solution as a liquid for supplying to the repulpator, task 18 corrects the device 22 depending on the concentration of the sugar-containing solution measured by the sensor 20. If the concentration of sucrose in the liquid supplied to the repulpator is zero, then signal P _{9 is} also equal to zero, that is, there is no correction of the flow rate of liquid into the repulpator based on sucrose concentration.

 In the steady state, the flow rates of lime and liquid to the extinguishing apparatus, their ratio, the moisture content of the fluff, its flow rate and the flow rate of liquid to the repulpator are constant. Therefore, the concentration of calcium hydroxide in milk of lime remains constant and equal to the specified.

When the flow rate of lime into the extinguishing apparatus changes, the signals P ₁ and P ₃ from the sensors change, as well as the corrective and control signals P ₈ , P ₅ and P ₆ , P ₁₁ , P ₁₀ in accordance with the algorithms of the devices, which leads to the necessary correction of fluid flow into the extinguishing apparatus and the repulpator. This leads to a constant concentration of calcium hydroxide in milk of lime.

In the case of a decrease in the moisture of the fluff, for example, with an increase in lime activity, less than the value of P _{ass. 1, the} device 13 will adjust the flow rate of the liquid to the extinguishing apparatus (signal P ₇ ) and will not allow the extinguished lime particles to exit the extinguishing apparatus.

To calculate the flow rate of the liquid into the repulpator, a computing device 21 is used, which, based on the signal P ₃ from the gun’s mass meter 19 and the signal P ₄ from the gun’s moisture sensor 14, generates a signal P ₆ supplied to the driver 18.

- ее расходом, кг/ч; Р_зад.2 - концентрацией гидроксида кальция в известковом молоке, % CaO;

- расходом жидкости для смешивания с пушонкой, кг/ч:

Использование изобретения позволяет повысить эффективность очистки соков сахарного производства за счет того, что улучшается качество известкового молока и обеспечивается стабильность концентрации в нем гидроксида кальция.The signal P _{6 is} calculated based on the functional relationship between B - the moisture content of the fluff,%;

- its flow rate, kg / h; P _{ass. 2} - the concentration of calcium hydroxide in milk of lime,% CaO;

- fluid flow rate for mixing with fluff, kg / h:

The use of the invention improves the efficiency of purification of sugar production juices due to the fact that the quality of milk of lime is improved and the concentration of calcium hydroxide in it is ensured.

Claims (2)

1. A method of controlling the process of preparing milk of lime, which involves the supply of lime and liquid to a quencher with the production of fluff, the separation of unextinguished particles and impurities from it, the regulation of the flow rate of the quenching, depending on the mass of lime and humidity of the resulting fluff, the supply of the latter and liquid to the repulpator and determining the mass of the fluff fluff and the flow rate of the fluid supplied to the repulpator, characterized in that the determination of the mass of fluff fluff is carried out by weighing it and the flow rate of fluid in my repulpator, calculated by the formula

where dm is the mass of fluid supplied to the repulpator, kg;

- flow rate of fluid supplied to the repulpator, kg / h;
K is the correction factor;
dm _push. - mass of fluff fed to the repulpator, kg;

- consumption of fluff fed to the repulpator, kg / h;
In - moisture fluff,%;
P _{ass. 2} - the specified concentration of calcium hydroxide in milk of lime,% CaO.  2. The method according to claim 1, characterized in that the sugar-containing solution is used as the liquid supplied to the repulpator and its consumption is determined taking into account the concentration of sucrose in it.