SU1249025A1 - Method for controlling process of polymerization or copolymerization of alpha-olefins in gaseous medium - Google Patents

Description

The invention relates to methods for controlling polymerization processes and can be used in the production of polyolefins in the chemical petrochemical and other industrial sectors.

The purpose of the invention is to reduce the consumption rates of the catalyst.

Figure 1 is a diagram of the device implementing the proposed control method; figure 2 - graphs of dependencies between process parameters.

Ethylene, hydrogen and carbon dioxide are fed to the polymerization reactor 1. Pressure and CO concentration in the reactor are stabilized with regulators 2 and 3, and hydrogen consumption is regulated with regulator 4.

The polymer consumption from the reactor, the catalyst to the reactor, the KCC quality indicator and the concentration of CO are measured respectively by sensors 5-8 and entered into the computing device 9 This is also the time limit for the ratio of the melt flow rates (KCC) and the specific productivity of the catalyst (CCP). ).

The specific productivity of the catalyst is calculated by the formula

CPC

 "

(ABOUT

where is the average polymer consumption of

reactor;

 average catalyst consumption. into the reactor.

Suppose, for example, as a result of an increase in the amount of finished impurities in the feedstock (CjHp, H, jO, Op) or a change in the properties of the catalyst of the CPC, it decreased from 0.8 to 0.5 t / kg. At the same time, the measured values of the concentration of COj (c) is 5 ppm, the ratio of the velocity ratio (CIL) is 36, 0.6 t / kg, 44.

Computing device 9 determines the new COf concentration setpoints, which provide for regulatory

. “Measure

+ C 3.40 ppm (2)

MO KS

and routine KCC:

 KCC ,, -, o // tch

C a -Ig pceTc + t, 2.34 ppin, (3)

/ -iMflitc nzl

where С% С, С - concentrations

- .COj, ppm;

CPC, CPC-,, CSC, measured and procedural limitations of the CCP, t / kg, and CIL, A, a are the coefficients depending on the produced polymer grade and the purity of the raw material (A 3 S, a, 5-15).

From two values of C and C, the best given value of CO concentration is calculated using the formulas

  with, (4). К (5)

25

C 2.94 ppm.

where K, k are the normalized coefficients that account for changes in the cost of production in violation of the limitations on the CPC or CIL, depending on the brand of polymer produced (K 0-1,).

Condition (5) occurs very rarely in the actual process, however

By controlling this method, a polymer is obtained that is closest to the regulatory indicators.

The calculation by formulas (2) - (5) is illustrated in graphs (Fig. 2). Next, the computing device 9 carries the calculated value of the CO concentration to the controller 3 as a task.

Technical implementation of the method

can be performed on computer hardware by means of electronics or pneumatic components of the system.

Control of the reactor according to the proposed method reduces the rate of catalyst by 5%, and the share of non-conforming product by 0.1%.

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Editor N., Bobkove

Sos; tavitel V.Shuvalov

 N. Bonkalo Corrector: V. But ha

Order 4197/23 Tysh.azh 4/0Subscription

VLIIPI USSR State Committee

on cases of emanations and discoveries 113035, Moscow, F-: 5, Ra tpska nab, d. 4/5

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Production of psligraf; by-enterprise, Uzhgorod, st. Project, 4

Claims (1)

METHOD FOR MANAGING THE POLYMERIZATION OR COLLIMERIZATION OF ALPHA-OLEFINS IN A GAS PHASE in the presence of a catalyst, hydrogen and carbon dioxide, which consists in controlling the pressure in the reactor by changing the flow rate of the monomer and the ratio of the melt flow rate by changing the flow rate of carbon dioxide, which, in order to reduce the rate of carbon dioxide, catalyst consumption, the regulation of the ratio of the melt flow rate is carried out taking into account changes in the specific productivity of the catalyst. polymerization, and change the flow of carbon dioxide in proportion to the value of the concentration of carbon dioxide in the reactor, the corresponding minimum value of the specific productivity of the polymerization catalyst and the maximum ratio of the melt flow rate. fui 1 1249025 A1