SU1095940A1 - Method of controlling the process of clarification of liquor - Google Patents

Abstract

The process of controlling the treatment of the liquor by regulating the flow rate of the flocta in the settling tank depending on the flow rate and density of the initial suspension, is characterized in that, in order to reduce the flow rate of the flocculant, the temperature in the sump is additionally measured and the flow rate is controlled depending on the measured parameters in the sump. g QD SL QD 4

Description

control of the process of clarification of liquor and can be used in the production of potash fertilizers. I There is a known process control method — condensation, in which the flow of coagulum into the thickener is controlled depending on the height of the clarified zone P.

The disadvantage of this method is that when it is used, the height sensor of the clarified zone quickly goes out of operation because of the aggressiveness of potash production. Known is the method of controlling the process of clarifying liquor by changing the flow rate of flocculant to the settler depending on the solid content in the suspension with correction for its granulometric composition C2. The disadvantage of this method of automatic control is the difficulty of automatically controlling the composition of the solid phase of the suspension on the process flow. in the absence of reliable granulometers. Existing models of granule meters have a long analysis cycle and are unsuitable for installation on a process stream. As a result, a large amount of flocculant (e.g. polyacrylamide) is consumed. The closest to the invention in technical essence and the achieved result is a method for controlling the process of clarification of liquor by controlling the flow rate of flocculant depending on the flow rate and density of the initial fsj suspension. The disadvantage of this method is that it does not take into account the temperature at which the process of clarification is carried out, which, in turn, leads to an excessive consumption of fluid in the sump. The purpose of the invention is to reduce the flow of flocculant. The goal is achieved by those that according to the method of controlling the production

By adjusting the flow rate of the liquor by adjusting the flow rate of flocculant to the sump depending on the flow rate and density of the initial suspension, the temperature in the sump is additionally measured and, depending on the measured parameters, the flow of flocculant to the sump is adjusted.

the functional function of the distribution of the clay particle size distribution at 20 ° C; mass ratio of liquid

phase: the solid phase is 670, the maximum e mass concentration of the solid (8.7%) corresponds to an average particle diameter of 3.5 µm.

FIG. 2 shows the differential function of the distribution of the clay size distribution at 20 ° C; the mass ratio of the liquid phase: solid phase is 167; maximum mass concentration

rum less than 10 microns is 35.4% w / w; at 35 C, this value increases to 48.8 wt.%, and at 65 ° С it reaches already 60.9 wt.%. The dispersion of particles leads, in turn, to an increase in flocculant consumption for precipitation, and the examples given indicate that a sufficiently objective solid (5.7%) corresponds to an average particle diameter of 8.5 μm. FIG. Figure 3 shows the differential distribution function of the clay particle size distribution at 35 ° C; the mass ratio of the liquid phase: solid phase is 167, the maximum mass concentration of the solid (6.5%) corresponds to an average particle diameter of 8.5 microns. FIG. 4 shows the differential distribution function of the clay particle size distribution at 65 ° C; the mass ratio of the liquid phase: solid phase is 167, the maximum mass concentration of the solid (10.2%) corresponds to a particle diameter of 3.5 µm. FIG. 5 is a schematic diagram of a control system implementing this method. From the comparison of the examples shown in FIG. t and 2, it can be seen that an increase in the density of the suspension (corresponding to a decrease in the ratio W: T) leads to an increase in the diameters of the particles under conditions of constrained sedimentation. The enlargement of particles, in turn, leads to a reduction in flocculant consumption for precipitation. Considering the effect of temperature on the particle size distribution (fig. 2 on the particle size composition (fig. 2-4), it can be noted that as the temperature rises, the particles of the solid phase disperse. So, at 20 ° C (fig. 2) the concentration of particles of diameter The granulometric composition of the suspensions using such indirect parameters as density and temperature. The method is carried out as follows: The suspension to be clarified is fed into a sump 1 (FIG. 5) of continuous operation. The clarified lye and thickened clay-salt slime discharged from the upper and lower parts of the apparatus, respectively. The flow rate of the solution Fpokul nta fed to the sump 1 is measured and adjusted by the secondary device 2 complete with the regulator and actuator 3. The density of the initial suspension, the temperature in the sump and the flow of the initial suspension are measured respectively a density meter 4, a temperature sensor 5, and a flow sensor 6. Signals from the density meter 4, the temperature sensor 5, and the flow sensor 6, which are proportional to the values of the measured parameters, go to the control computer 25 troystvo 7, wherein the predetermined calculation is performed flocculant solution flow into the sump by the equation: (ao + ap) Ff. where is the specified flow rate of the solution f okul nta p sump, m / h; Zo a ,, - constant coefficients; a2. T is the temperature in the sump, ° C; P is the density of the suspension, FC is the flow of the suspension in the sump, m / h. The task from the control computing device 7 is fed to the secondary device 2 with a controller that changes the flow rate of flocculus into the sump 1. Using this method allows you to reduce the flow rate of flocculant (polyacrylamide) and achieve stable indicators of the thickening process.

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Claims (1)

METHOD FOR MANAGING THE PROCESS OF LIGHTING THE ALKALINE by adjusting the flow rate of the flocculant. To the sump, depending on the flow rate and density of the initial suspension, characterized in that, in order to reduce the flow of flocculant, it is additional. but measure the temperature in the sump and depending on the measured parameters regulate the flow of flocculant into the sump. n.SU., „1095940>