SU780844A1 - Apparatus for automatic regulation of evaporation process - Google Patents

Description

V The invention relates to a device for you to automatically regulate the processes of evaporation of multicomponent salt solutions in vacuum boilers, namely to control the concentration of one stripped off solution, and can be used in chemical production enterprises, nonferrous metallurgy, for example, for automatic control of the processes of evaporation of soda-pulp solutions complex processing of nepheline. A device for automatic control of the evaporation process is known, including sensors for the boiling point of the evaporated solution and the vapor pressure, which are connected via an intermediate relay to a controller connected to the heat supply or solution valve to the evaporator 1. The closest to the invention is the technical essence of the invention. for automatically controlling the evaporation process, comprising a solution boiling point sensor and a vapor pressure sensor above the solution, connected via converters to Odes of the adder, the output of which is connected to a regulator connected to the actuator for feeding the heat carrier or the initial solution to the evaporator 2. However, when the vapor pressure above the solution varies within ± 0.2 kgf / cm, the output signal of the adder does not correspond to the actual concentration of the evaporated solution, this is due to the non-linear: air pressure between the temperature of the boiling solution and the vapor pressure above the solution, and the error in stabilizing the concentration of the solution is in the order of 10% of the specified value. Such an error is unacceptable under the terms of the technological regulations. In addition, an additional error arises in connection with the fact that the change in the boiling point of the solution occurs with some delay relative to the change in pressure. The change in vapor pressure in the apparatus is due to the fact that, during the heating and evaporation of the solution, sodium aluminosilicate is released, which is deposited in a thin layer on the surface of the heating tubes of the evaporators and heaters, and in addition, changes in the pressure in the vacuum system.

The purpose of the invention is to preserve the concentration of the dilated solution and reduce the energy consumption during the evaporation of Multiple Compound salt solutions in vacuum mics. -. ..-.:.; 5 ..., -.... l ..-. The goal is achieved by the fact that the device additionally contains flow sensors for the initial solution and main component components, a nonlinearity unit with a delay line and a correction unit, while the pressure sensor is connected to the input of the nonlinearity unit, the output of which is connected to the second input of the adder, the output of the latter is connected to one of the I / O devices of the correction unit, the other input of which is connected to the sensor for holding the main component in the IC, and the output of the correcting unit is connected with one of the controller inputs, etc. The main input of which is connected to the Flow Sensor of the outgoing paciTBfefpai :; ; :. :: .-: -. - ...---. The drawing shows a diagram of the device: - ..;. .

; The device comprises a vapor pressure sensor 1 above the solution, connected via a nonlinearity block 2 to a delay line with an adder 3, the input koiporO is connected to the solution 4 boiling temperature sensor 4, a correction block 5 connected to the adder 3 and the main component content sensor b in solution, the regulator 7, associated with the correction block 5 and the sensor 8 flow rate of the initial solution, the output of the regulator 7 is connected to the actuator 9 supplying the initial solution to the device

-lo- .:. :.:.:.: -.- v; ,

The device works as follows .. ..--.:. / The original solution to be in, the steaming, is fed to the evaporator 1o, on which the temperature sensor 4 is installed kypey evaporated.mogr of the solution, which is responsible for the temperature of the cellar and converts it

& a unified signal p6c bieby current and a vapor pressure sensor 1 above the solution / also converts pressure in the vacuum system into a signal of a parallel current. The concentration of the evaporated solution is stabilized by OR by changing the feed solution, by evaporation, or by measuring the flow of fresh steam into the heater. When the concentrations of 1 solution are off from a given value, the boiling temperature paicTBOpa and the pressure of the vapor above the solution change. At the same time, the temperature of the cypeic solution, which depends on the pressure in the apparatus and on the correlation of the com-. ponytov in the outgoing solution. Ymeyyonye The boiling temperatures of the booster and the pressure in the apparatus are connected

A linear dependence, in addition, between the corresponding changes in these signals, there is a transport delay, since the change in the temperature of the solution has greater inertia, the 4th change in pressure. In order to compensate for the nonlinearity of the indicated dependence and difference in, the velocity of the signals by the boiling point of the solution and the vapor pressure above the solution in the apparatus, a nonlinearity unit 2 is inserted into the device with a delay line embedded in it. Unit 2 is connected by its input with sensor 1, and output with adder 3. Boiling point sensor 4 is connected to the second input of adder. In block 2 nonlinearity with a delay line, a signal is generated

U f (). Thus, in the adder 3, the change in the boiling point value is corrected from the change in the pressure value with a shift in B time at a constant concentration of the evaporated solution. The signal at the output of the adder 3 has a read

output g- ° rP P b

6S

where a, a, are constant coefficients, and t is the boiling point of pps. - solution: P - pressure of secondary steam Formed in adder 3, signal, compensated by pressure and in time, is fed to the first input of the correction unit 5, which also entered its second input with sensor b of the main component content in the initial solution, output the correction unit is connected to the supply solution regulator 7 of the heat carrier in the evaporator. In the correction unit 5, the signal from the adder 3 is impacted by the content of the main component, for example, in soda thief, realized by linear law. A new signal is presented in

the form. ,: „

Thus obtained value of the temperature of the boiling point of the evaporated

55 (the solution is absolutely uniquely consistent with the concentration of one stripped off solution. This signal as a correction for setting the boiling point of the solution is fed to the input

XQ regulator 7, another input regulator is connected to the solution flow sensor 8 or with the steam consumption sensor 11. The deviation of the concentration of the solution from the target causes a corresponding change in its boiling point

Claims (1)

The claims of re A device for automatically controlling the evaporation process, comprising a solution boiling point sensor connected to the first input of the adder, a regulator connected to the steam actuator above the solution, and therefore, in order to increase the accuracy of maintaining the solution concentration and reducing energy consumption by increasing the accuracy of regulation, it additionally contains sensors for the flow rate of the initial solution and the content of the main component in it, a nonlinearity block with a line. delays and a correcting unit, while the pressure sensor is connected to the input of the nonlinearity unit, the output of which is connected to the second input of the adder, the output of the latter is connected to one of the inputs of the correcting unit, the other input of which is connected to the sensor of the content of the main component in the initial solution, and the output of the correcting unit is connected to one of the inputs of the controller, the other input of which is connected to the flow sensor of the initial solution.