SU726026A1 - Method of automatic control of natural water acidification process - Google Patents

Description

The invention relates to the automation of technological processes and can be used in the energy and utilities sector when managing acidification * natural water processes.

A known method of automatically controlling the process of acidification of natural water by changing the ratio of the flow rates of natural water 'and a solution of acid in the mixer, depending on the pH value of acidified water after the mixer [1].

The known method has the disadvantage that the method is not provided. It reads the specified accuracy of regulation of the pH value after the mixer.

A known method of automatically controlling the process of acidification of natural water bypassing natural water bypassing the mixer by changing the ratio of the costs of natural water and an acid solution to the mixer, depending on the pH value of acidified water, the conductivity of natural water and the conductivity of acidified water after the mixer to the end of the bypass along the water [ 2].

The known method of regulation has the disadvantage that, when the alkalinity of the source water changes by ± 5 - 1000, existing in real conditions, it does not provide. preset accuracy of stabilization of the pH value of acidified water after the mixer.

The aim of the invention is to improve the accuracy of stabilization of the pH value of acidified water after the mixer.

This goal is achieved by changing the ratio of the flow rate of natural water to the mixer and bypass depending on the pH value of natural water.

The drawing shows a diagram of automatic control that implements the proposed method.

The automatic control scheme consists of a natural water supply pipe 1, a mixer 2, an acid supply pipe 3, a pump 4, a pipe 5 bypassing natural water bypassing the mixer, a flow meter

6, measuring the flow rate of natural water through a mixer 2, a regulator 7, a sensor 8 for the conductivity of natural water, a sensor 9 for the conductivity of acidified water, a sensor 10 for a pH value of acidified water, a measuring and functional unit 11, a flow meter 12 measuring the flow of natural water through a bypass pipe 5, the regulator 13, the valve 14 on the bypass pipe 5, the sensor 15 of the pH value of natural water.

A method for automatically regulating the process of acidification of natural water is as follows.

Natural water is supplied through pipeline 1 to mixer 2, where it is mixed with an acid solution supplied through pipeline 3 by pump 4. Natural water is bypassed bypass mixer 2 through pipeline 5. Bypassing natural water bypassing mixer 2 allows you to shift the change range alkalinity after mixer 2 into the working area of the conductivity and pH sensors, while after a bypass the set value of alkalinity of acidified water is restored. ''

When dosing acid into natural alkaline water, which is a buffer solution, the alkalinity of water decreases, while with a change in alkalinity from 3.5 mEq / l or more to 0.5-0.25 mEq / l, the pH value of water decreases, and the value of the electrical conductivity of water is practically unchanged. With continued dosing of the acid and a decrease in alkalinity from 03 mEq / L to zero, the pH value decreases sharply, the electrical conductivity begins to increase slightly, then with an increase in the acidity of water, the pH value decreases slightly (with an acidity of 0-0.5 mEq / L) and then practically very little changes, the electrical conductivity, on the contrary, begins to increase sharply and linearly. These patterns are repeated ’with different conductivity (and quality) of the source water, with a pH of 3.5-4 (with alkalinity equal to zero), and the change in conductivity remains almost linear with a constant coefficient that does not depend on the quality of the source water.

Used according to the proposed method, the reception of the summation of the signals from the sensor pH and differential conductivity makes it possible to obtain unambiguous information about the change in alkalinity of water in the range from 3.5 to + 3.5 mEq / l.

The flow rate of natural water through the mixer 2 is measured using a flowmeter 6, the ratio of flow rates of natural water and acid solution according to the signals from the flowmeter 6 and pump 4 is stabilized using the controller 7, affecting the performance of the pump 4.

The electrical conductivity of natural water is measured using a casing 8, the conductivity of acidified water is measured using a sensor 9, the pH value of acidified water is measured using a sensor 10. The signals from these sensors 8-10 are taken into account (summed) using the measuring and functional unit 11, with which set the task to the regulator 7.

The flow of natural water through the bypass pipe 5 is measured using a flow meter 12. The ratio of the flow of natural water to the mixer 2 and the bypass pipe 5 is supported by the regulator 13 by the signals from the flow meters 6 and 12, acting on the valve 14 on the bypass pipe 5. The ratio these costs vary depending on the pH value of natural water, measured using a sensor 15, the pH value. The indicated change in the ratio of the flow rates of natural water through mixer 2 and bypass pipe 5 allows even with large changes in the quality (alkalinity) of the source water to stabilize the range of alkalinity after mixer 2 in the working area of the conductivity sensors and the pH value, while the set alkalinity of acidified water is restored after the bypass .

Using the proposed method in comparison with the known method will approximately increase the accuracy of regulating the pH by 1.5 times, since it is assumed to use an additional measurement of the pH of the source water with a suitable sensor, which eliminates the influence of disturbances in the quality of the source water and the change in the flow rate of the source water.

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Claims (2)

1.Catalogue firm Fabkok, Germany, 1965. 2. USSR author's certificate in case no. 2012627/26. 04/12/74 (prototype).