Method for checking the functional dependence of the molecular weight of the polymer from indirect parameters

 

(57) Abstract:

The invention relates to the field of study of physico-chemical parameters of polymer melts and can be used in the manufacture of chemical fibers and plastics. The invention improves the accuracy of measurements by clarifying the functional dependence of the molecular weight of the polymer from indirect parameters and scale factors. The method consists in the fact that the molecular weight of the polymer is measured using the functional dependence of its value on the power consumed by the motor of the stirrer of the reactor in which the polymer, as well as from indirect parameters from loading the reactor, the temperature of the polymer, from the voltage and frequency of the electric network from losses in the electric mixer. Alternately 1st jump modify each of the indirect parameters, leaving unchanged all other indirect parameters. After the 1st of the transition process in the electric mixer 2nd abrupt change of the same indirect parameter. After the end of the 2nd transition process to produce the interpolation of the measured values of molecular weight within the time interval from the beginning of the 1st jump before the end of the 2nd transition is judged on the accuracy of functional dependence. 1 C.p. f-crystals, 1 Il.

The invention relates to the field of study of physico-chemical parameters of polymer melts and can be used in the manufacture of chemical fibers and plastics.

There is a method of measuring the molecular weight of the polymer, which is implemented in the device [1], which consists in the fact that the molecular weight of the polymer is measured using a functional dependence from the size of the polymer's viscosity and its temperature.

The disadvantage of this method is the impossibility of a simple and rapid test functional dependence of molecular weight on the temperature in the production of polymers and their processing for a specific technological device, reactor.

The closest analogue is the method implemented in the device [2] , is intended to measure the molecular weight of the polymer based on indirect parameters in the reactor with stirrer, using as the main parameter of the power of the motor of the agitator.

The disadvantage of this method is the impossibility of quick, simple, quick and reliable monitoring and verification functional dependence of the molecular weight of the polymer from indirect parameters and correct the ASS="ptx2">

An object of the invention is to improve the accuracy of measurements clarify the functional dependence of the molecular weight of the polymer from indirect parameters for each apparatus, the reactor in which the polymer, by clarifying the scale factors.

The problem is solved as follows.

The molecular weight of the polymer in the reactor with stirrer, measured with the device [2], which uses the functional dependence of the molecular weight of the power consumed by the motor of the stirrer of the reactor in which the polymer using power as the main parameter measurements, and indirect parameters.

Alternately 1st jump modify each of the indirect parameters, for example, downward by an amount not exceeding the limits of technological regulations, leaving unchanged all other indirect parameters.

Comes 1st transition in the electric mixer, accompanied by changes in electrical and mechanical parameters of the electric drive, which ends at time equal to 4, the time constant of the transition process.

P is the parameter, for example, in the direction of increasing by the same amount, not exceeding the limits of technological regulations, leaving unchanged all other indirect parameters. Comes 2nd transition in the electric mixer, which also ends at time 4 . After the end of the 2nd transition process produce interpolation, for example, a graph of measured values of molecular weight within the time interval from the beginning of the 1st abrupt changes in indirect parameter until the end of the 2nd transition.

As an example in Fig. 1 graphically presents the illustration of the determination of the difference between when a sudden change of voltage 3-phase electric network connected to the motor of the agitator.

Measurement of molecular weight (weight) M produced by the device [2], using the following formula showing the dependence of M on indirect parameters: including from the voltage

< / BR>
where Nnthe power consumed by the motor of the stirrer;

U1U2U3- line voltage 3-phase electric network;

Un- rated voltage of the electrical network;

f is the frequency, e is the second voltage;

T is the temperature.

Formula (I) reflects the dependence of M on indirect parameters in the regime of slow changes and does not take into account transient processes in electric mixer, occurs when a sudden change of indirect parameters included in the formula (I).

At time t10produced 1st surge voltage 3-phase electric network downwards.

Because the formula (I) does not take into account the transition process after a sudden change of the voltage on the chart recording instrument, fixing the value of molecular weight, appears 1st "trace" from the 1st of abrupt change in voltage in the time interval from t10to t1till time t1the end of the 1st transition process.

The drive parameters of the mixer such that the transition process, coming as a result of abrupt change in voltage, ends for a few seconds at a time, as technological processes associated with obtaining and processing of polymers, usually last for tens of minutes, hours. Therefore, the end of the transition process clearly defined on the chart recording instrument.20. 2nd "step" voltage leaves the 2nd "trace", which ends at time t2the end of the 2nd transition.

After the end of the 2nd transition was made graphical interpolation of the values of molecular weight in the time interval t10< t < t2as follows.

The values of molecular mass M10and M2at time t10and t2respectively, were connected by a smooth curve line, as they (M10and M2) were changed at the same voltage 3-phase electrical network.

In the time interval t1< t < t20for time tthe chart recording instrument was conducted by a vertical line parallel to the ordinate scale, which crossed the curve of the change of molecular weight in the point Mand the extrapolated curve is at point Me. Difference = Me-M(2) characterizes the accuracy of the functional dependence of molecular weight on voltage 3-phase electrical network. When the difference value between zero effect a change of scale factor NSTNfor example, upward and repeat abrupt change in napryazheniem is not reduced, change NSTNdownward.

If not brought these events to zero, carry out similar actions, changing the scale factor K1.

Then repeat the same steps with NSTNand so on, to obtain = 0.

The sources of information.

1. A. S. N 978015 (USSR). Device for automatic measurement of the molecular weight of the polymer.

2. A. S. N 353179 (USSR). Device for automatic measurement of the molecular weight of the polymer.

1. Method for checking the functional dependence of the molecular weight of the polymer from indirect parameters, namely, the molecular weight of the polymer is measured using the functional dependence of its value on the power consumed by the motor of the stirrer of the reactor in which the polymer using power as the main parameter measurements, and indirect parameters from loading the reactor, the temperature of the polymer, from the voltage and frequency of the electric network from losses in the electric mixer, wherein alternately 1st jump modify each of the indirect parameters, after the 1st of the transition process in the electric mixer, Viswanathan 2nd transition in the electric mixer, caused the 2nd jump, perform interpolation of the measured values of molecular weight within the time interval from the beginning of the 1st abrupt changes in indirect parameter until the end of the 2nd transition in the electric mixer, caused by the 2nd abrupt changes in indirect parameter, and the difference between the measured molecular weight and the resulting interpolation in the time interval between the end of the 1st transition time and the 2nd abrupt changes in indirect parameter to judge the accuracy of functional dependence, according to the truth, if the difference is equal to zero, consider what functional dependence and scale factors included in it, are true, if the difference is not equal to zero, change the functional dependence and scale factors, and then repeat the whole cycle of changes of the same indirect parameter and proposed measurement up until the difference becomes zero.

2. The method according to p. 1, namely, that the first leap modify each of the indirect options downward by an amount not exceeding the limits of technological regulations and in the

 

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