SU1168549A1 - Method of automatic control for process isolating synthetic fatty acids from their salts with carbonic acids - Google Patents

Abstract

THE AUTOMATIC CONTROL METHOD FOR THE PROCESS OF IMPLEMENTATION OF SYNTHETIC FATTY ACIDS FROM THEIR SALTS WITH CARBONIC ACID by changing the carbon dioxide consumption depending on the consumption of the solution of synthetic fatty acid salts in the reactor, corrected by the output of the reactor, I’re like and I’t like, I’re like and I’re like and I’re like and I’t like a different person. free monocarboxylic acids, additionally measure the amount of acid soap and regulate the consumption of carbon dioxide in direct proportion to the product of the amount of acid soap and viscosity the reaction mass. (L O5 00 O1 4 CO

Description

The invention relates to methods for the automatic control of chemical-technological processes, in particular the control of the process of isolation. NIN synthetic fatty acids (FFA) carbonic acid, and can be used in the chemical industry.

A known method of controlling the process of separating FFA from their salts by changing the flow rate of carbon dioxide is proportional to the change in the flow rate of the initial solution of salts of CHIcfl

The disadvantage of this control method is inconsistency. concentration of the initial solution of FLC salts, which can vary in a wide range and is often random. The process of excretion of FFA by carbonic acid is very sensitive to changes in the concentration of the crude solution of the salts of FFA,

The closest in technical essence to the present invention is a method for automatically controlling the process of extracting synthetic fatty acids from their salts with carbon dioxide by changing the consumption of carbon dioxide depending on the consumption of a solution of salts of synthetic fatty acids fed into the reactor, with a correction of the viscosity of the reaction mass at the reactor outlet. 12.

A disadvantage of the known control method is that it does not provide a high yield of free monocarboxylic acids as it does not take into account the output of the acid soap.

The aim of the invention is to increase the yield of free monocarboxylic acids.

The goal is achieved in that according to the method of automatically controlling the process of synthetic fatty acids from their salts by carbon dioxide by changing the carbon dioxide consumption depending on the consumption of synthetic fatty acid salts solution fed to the reactor, the viscosity of the reaction mass at the reactor outlet is additionally measured the amount of acidic acid and regulate the consumption of carbon dioxide is directly proportional to the product of the amount of acidic soap and the viscosity of the reaction mass.

FIG. Figure 1 shows the relationship between the viscosity of the reaction mass and the depth of decomposition of FLC salts; in fig. 2 shows the calculated dependence of the yield of free monocarboxylic acids on the decomposition depth of the salt of the FFA in FIG. 3 - scheme of the implementation of the proposed method. The technological task of the process of allocating synthetic fatty acids (FFA) with carbon dioxide is to obtain the maximum yield of free monocarboxylic acids. It is natural to expect a maximum yield of free monocarboxylic acids with a maximum yield of acidic mines with a high depth of decomposition of the FFA salts. But the output of the acidic soap is direct, and the depth of decomposition is inversely related to the concentration of the salt of the FFA. The highest depth of decomposition is achieved at low concentrations of the FFA salt solution. But at low concentrations of the solution, the output of the acidic soap will also be low, because the acidic soap is a mixture of free monocarboxylic acids separated from the salts of FFA during carbon dioxide decomposition and not decomposed salts of FFA. Therefore, the task of automatic process control in the field of its optimal parameters arises.

The study of the technological process showed that at stabilization of pressure and temperature in the reactor at their optimal values, the yield of free monocarboxylic acids depends on the viscosity of the reaction mass and the yield of acid soap.

The yield of free monocarboxylic acids is determined by the values of the decomposition depth of the FLC salts and the yield of acidic acid, related to

Y - g-Y, 1 100

where Y is the yield of free monocarboxylic acids, kg / h:

Od- yield acidic kg kg / h;

Y2 is the depth of decomposition of salts of SLC.

Automatic measurement in the output stream of acidic by means of industrial devices produced by labor does not represent, but it is impossible to measure automatically in the flow the decomposition depth of salts of FLC at the present time due to the absence of instruments. It can be determined only by laboratory analysis, which lasts about two times days. A close correlation relationship has been established between the decomposition depth of the FLC salts and the VISCOSITY of the reaction mass (the correlation coefficient is 0.9) Based on this, a method has been proposed to indirectly determine the viscosity of the FFA salts for the decomposition of the FLC salts, which is automatically measured in the flow With the help of commercially available viscometers. From the equation of the maximum theoretical regression line, the relationship between the viscosity of the reaction mass and the deep decomposition of the FLC salts gives a convenient formula for of the decomposition of FLC salts through the reaction mass: Y 151-1,74 Y, (1) Y 51-Y4 where 1 where Y. is the viscosity of the reaction mass Pa s. From the experiment according to the scheme of central composite rotatable second pore planning Both obtain adequate regression equations linking the dependence of the yield of free monocarbonic acids and the depth of decomposition on the process parameters: i 1.82 + 0,, 099X2 + + 0.255X3 + 0.027X + 0 ,,, 058X2-0,, 133X, X, -0, IX, Xs + 0.0255X, 0.004X2Khz-0 ,, +. + 0,114ХзХ; (B: Y 50.54 + 5,, 69Xj, -. + 5, 79X + 1,, 048X2-0.046X | + + 0.203X2-0.046X | -0,, 149-0.049Xi, 449 X2 X4-0, 112, (4) where X is the pressure in the reactor, Pa; Xj is the temperature in the reactor, K X is the concentration of the FFA salt solution,%; X is the carbon dioxide consumption, expressed as the ratio of the working flow rate to theoretical The presented dependences allow one to determine the optimal technological parameters at which the maximum yield of free monocarboxylic acids is achieved, i.e., to solve the problem of static process optimization, since the yield of free monocarboxylic acids in equations (4) you Agen through the output of the acidic yield and the depth of decomposition of FLC salts, it is impossible to determine the optimal conditions for conducting the process directly from it, because some process parameters, for example, the concentration of the solution of FLC salts, have a direct opposite effect on the decomposition of FLC salts and on the output of acid soap Therefore, in order to find the optimal process conditions, the problem of finding the maximum of the functions Y | with limitations on function 2 The maximum of functions (Fig. 2) with a limit on the decomposition depth of FLC salts equal to 52.1% is provided with the following process parameters: pressure 3.92-103 Pa, temperature 328 K, concentration of salt solution FLC 20%, the ratio of the working carbon dioxide consumption to the theoretical one is equal to 5. Technologically, it is possible to hold these parameters in the optimal range, except for the concentration of the FFA salt solution, the change of which depends on the preceding stages and is random for this process. elichinoy.Kompensirovat disturbances to change FFA salt concentrations of carbon dioxide can flow. Automatic control of the selection process. SLC of their salts with carbon dioxide reduces to stabilizing the pressure and temperature in the region of optimal values and adjusting the task of regulating the ratio of the expenses of the solution of salts of SFA and carbon dioxide to a signal proportional to the product of the output of the acid soap on the viscosity of the reaction mass so as to stabilize it at a given value , changing carbon dioxide consumption. Viscometer 1 measures the viscosity of the reaction mass at the outlet of reactor 2, and sensor 3 measures the flow rate of the acidic outlet at the outlet of the autoclave.

settler 4. The signals from the viscometer 1 and the flow sensor 3 are fed to the functional unit 5, the output of which is fed to the regulator 6. The output of the regulator 6 is connected to the ratio regulator 7, to the input of which signals are received from the sensors 8 and 9 of the flow, respectively carbon dioxide and a solution of salts of synthetic fatty acids. Carbon dioxide consumption is regulated by means of a control valve 10.

The method is carried out as follows.

With an increase in the concentration of the salt solution of the FFA (deviation from the optimum), to ensure the former yield of free monocarboxylic acids, it is necessary to increase the consumption and carbon dioxide. Since the yield of free monocarboxylic acids on the installation cannot be measured (they are part of the acid soap), it is determined through the product of the output of the acid soap on the viscosity of the reaction mass, which are continuously measured on the installation using sensors 3 and 1. The output signals from these sensors are multiplied in the functional block 5, the output of which is fed to the input of the regulator 6 By specifying this regulator, a signal is set proportional to the product of the viscosity of the reaction mass to the output of the acidic mouse The second corresponds to the maximum yield of free monocarboxylic acids.

The output of the regulator 6 enters the regulator 7 of the ratio of the consumption of carbon dioxide and the solution of FLC salts as a signal correcting the task. The regulator 7, controlling the position of the regulator of the valve 10, changes (in this case increases) the consumption of carbon dioxide until the value of the viscosity of the reaction mass on the output of the acidic mouse becomes equal to the value set by the regulator 6.

Adjustment is carried out similarly with a decrease in the concentration of the FFA salt solution.

Example. The maximum yield of free monocarboxylic acids with a decomposition depth of 52.1% (Fig. 2

According to formula (2), the viscosity of the reaction mass is 60.346 Pa. At optimal parameters, the process (pressure 392 -10 Pa. temperature 328K, concentration of salt solution of FFA 20%, ratio of working carbon dioxide consumption to theoretical, equal to 5, and consumption of salt solution of FLC, equal to 13.6 kg / h, at the pilot plant, the yield of acidic soap was 5.35 kg / h with a carbon dioxide consumption of 23.2 kg / h. The product of the viscosity of the reaction mass and the yield of acid soap under these optimal conditions is 322.9 At the same time, the yield of free monocarboxylic acids is 2 , 79 kg / h.

Process control is reduced to maintaining a constant of this product in case of disturbances in the concentration of the FFA salt solution by changing the carbon dioxide consumption in proportion to the deviation of the named product from the specified value.

So, when increasing the concentration of the FFA salt solution to 22% / deviation from the optimum by + 2%) to ensure the previous (2.79 kg / h) yield of free monocarboxylic acids, it is necessary in accordance with formula (4) to increase the carbon dioxide consumption to 28.23 kg / h Since the yield of free monocarboxylic acids in the installation cannot be measured (they are part of the acid soap), according to formula (1) it is determined through the product of the output of the acid soap on the viscosity of the reaction mass, which is continuously measured on the installation using serial devices. The output signals from these devices are multiplied in the functional block 5 (FIG. 3), the output of which is fed to the input of the controller 6. By setting this controller, a signal is set that is proportional to the value of the viscosity of the reaction mass at the output of the acidic mun, equal to 322.9 corresponds to the maximum yield of free monocarboxylic acids.

The output of the regulator 6 enters the regulator 7 of the ratio of carbon dioxide consumption and the FFA salt solution as a signal correcting the task. Regulator 7, control

7,

the position of the valve 10, changes (in this case increases) carbon dioxide consumption until the value of the product viscosity of the reaction mass at the output of the acidic pump becomes equal to the value set by the controller 6 .. When the concentration ratio of the FFA salt solution decreases to 18 % (deviation from the optimum by .- 2%) to ensure a given yield of free monocarboxylic acids, it is necessary in accordance with formula (4) to reduce the carbon dioxide consumption to 20.89 kr / h.

498

In order to provide a predetermined regulator 6 of the value (322.9) of the product of the viscosity of the reaction mixture at the output of the acid soap, the regulator 7 reduces the carbon dioxide consumption until the informative signal received from regulator 6 becomes equal to the reference signal.

Thus, the proposed control method ensures a stable yield of free monocarboxylic acids at the maximum possible value with the presence of disturbances in the concentration of salts of FFA,

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Claims (1)

METHOD FOR AUTOMATIC CONTROL OF THE PROCESS OF INCREASING SYNTHETIC FATTY ACIDS FROM THEIR SALTS CARBON ACID by changing the carbon dioxide consumption depending on the flow rate of the solution of synthetic fatty acid salts supplied to the reactor, with a correction for the viscosity of the reaction mass at the outlet of the reactor, characterized in that, in order to increase the yield of free monocarboxylic acids, the amount of acid soap is additionally measured and the flow rate controlled carbon dioxide is directly proportional to the product of the amount of acid soap and the viscosity of the reaction mass. SU ... 1168549 1 168549