SU967950A1 - Method of automatic control of calcium borate sedimentation process - Google Patents

Description

This invention relates to methods for controlling a calcium borate precipitation process and can be applied in chemical industry.

There is a known method of controlling the operation of the reactor by extreme regulation of the consumption of raw materials in the reactor depending on the consumption of the target product, determined by multiplying the consumption of raw materials by the concentration of the target product in the reaction mixture Ci.

However, with this control method, due to fluctuations in the concentration of the target component in the reaction mixture, it is impossible to obtain a finished product of a given quality.

There is also known a method for automatically controlling semi-continuous processes in a reactor by adjusting the stirring speed depending on the viscosity of the medium being mixed, supplying initial reagents S depending on the temperature in the reactor, controlling the refrigerant supply, initial reagents and mixing speed depending on the sum of viscosity signals and volume reaction mass 2.

However, the feed of the initial reagents by the value of the viscosity for the process

the precipitation of borate-calcium will lead to fluctuations in the ratio WdO / CaOv of the finished product and the loss of the target component with the discharge.

The closest in technical essence to the invention is a method of automatic control of the precipitation process by adjusting the pH value in a reactor with add.

10 by a correction of the dynamic adjustment of the regulator with respect to the ratio of the reagent consumption to the pH value at the entrance to the reactor C3.

However, the use of known

15 of the method leads to an increase in boric acid losses in the discharge of the reactor due to the lack of control over the density of the thickened slurry in the reactor and the temperature of milk of lime.

The aim of the invention is to reduce the concentration of boric acid in the reactor discharge at a given ratio Bj Oj / CaO in calcium borate.

25

The goal is achieved by adjusting the temperature of milk of lime, depending on the density of the thickened suspension in the reactor and the concentration of the boron solution.

Claims (3)

30 acid at the entrance to the reactor, which adjust the pH value in the reactor. The drawing shows a block diagram of a device that implements a method for automatically controlling the process of calcium borate precipitation. The device contains a reactor 1, a heat exchanger 2, a milk milk temperature regulator 3, a milk milk temperature sensor, a regulator organ 5, a pH controller b, a pH sensor 7, a regulator body 8, a condensed suspension density sensor 9, a concentration sensor 10 for boric acid computing device 11. The method is carried out as follows. A solution of boric acid () and milk of lime (Ca (OH) 2), which react chemically to form calcium borate, is continuously fed to the calcium borate precipitation reactor 1, the calcium borate is discharged from the bottom of the reactor 1. From the upper part of the reaction; 1 there is a drain of unreacted boric acid solution. The milk of lime is fed into the reactor 1 through the heat exchanger 2. The temperatures of the milk of lime are controlled using the temperature controller 3, the temperature sensor 4 and the regulator 5 placed on the refrigerant supply pipe to the heat exchanger 2. The pH value measured by the sensor 7 in the reactor carried out with the help of the regulator 6 and the regulator 8, placed on the milk milk supply pipeline to the reactor 1. The task for the temperature controller 3 is calculated in the computing device 11 in the factory values of the concentration of boric acid solution at the reactor inlet and the density of the condensed suspension in the regulator measured by sensors 10 and 9. In computing device 11, the pH controller b is also calculated depending on the concentration of boric acid at the reactor inlet, measured sensor 10. Signals from sensors 9 and 10 are fed to computing device 11, where boric acid concentrations in the reactor discharge and in calcium borate are predicted. The calculation is based on the use of the following dependencies Cp K e + iqp-f k, с Co 4- KjpH; no concentration of boric acid i in the overflow of the reactor; Cp is the ratio in calcium borate; - pH value in the reactor - concentration of boric acid solution; - density in the reactor; milk of lime temperature; K, K, K, K, K - coefficients. The tasks for regulators 3 and 6 are calculated according to the following dependencies obtained from expressions (1) and (2): -Kfcp-KaC. , H) where is the task of regulating the temperature of milk of lime; PH adjustment; (- the routine value of boric acid concentration in the reactor discharge; C is the specified calcium borate ratio 1 Bj Oj / CaO S. Using the proposed method will reduce the concentration of boric acid in the reactor discharge by 0.05-0.1% at a given ratio Bjj Oj CaO and calcium borate and increase reactor productivity. Formulation of the method for automatically controlling the calcium borate precipitation process by adjusting the pH in the reactor, characterized in that, in order to reduce the boric acid concentration in the discharge, at a given ratio of BijOj / CaO in calcium borate, regulate the temperature of milk of lime Depending on the density of the thickened suspension in the reactor and the concentration of boric acid solution at the reactor inlet, which corrects the value of p in the reactor. USSR Author's Certificate 581980, class C 01 B 35/00, 1977. 2. ABTOpCKoie certificate of the USSR 465215, cl. From 01 to 35/00, 1975. 3. Copyright certificate dcCP 399461, cl. From 01 to 35/00, 1973. Hjsoi I G 0 C / uif i five