SU1287933A1 - Method of automatic regulation of value ph in reactor of periodic action - Google Patents

Abstract

The invention relates to a method for automatically adjusting the pH value in a batch reactor, can be used in the chemical industry and allows increasing the productivity of the reactor by improving the quality of regulation. The method is implemented by an SAR comprising a neutralizing supply control loop; agent depending on the pH of the reaction medium (pH sensor 8, computing device 3, control valve 7) with a correction in the amount of agent supplied (flow meter 5) and the concentration of the medium in the supply tank (concentrator 4). 1 il.

Description

The invention relates to the field of automation of chemical-technological processes and can be used in chemical and other related fields.

The chain of the invention is to increase the productivity of the reactor by increasing the quality of regulation.

The drawing shows a schematic diagram of the automatic control of the process of the flow of hydrochloric acid into the sulfenamide C synthesis reactor (L-cyclohexylbenzthiazolyl-2-sulfenamide), which implements the proposed method.

The scheme contains sulfenamide C synthesis reactor 1, hydrochloric acid supply tank 2, control computer 3 with converters, concentration meter 4, flow meter 5, control valve 6, shut-off valve 7, pH meter 8 sensor, temperature sensors Hey 10.

The method is carried out as follows.

The control computing device 3 is set to the desired pH value and the initial volume of the reaction mass in reactor 1. After this, an initial sensor survey is performed, which results in determining the concentration and temperature of the supplied acid from the supply tank 2, the initial pH value of the reaction mass and its temperature. Then, the controlled computing device 3 calculates such values of the acid consumption so that when the reagent rushes in, the temperature of the reaction mass does not become higher than

 (T - T,)

  h,

- s (t - t ..)

x

de T is the temperature of the reaction mass, s;

Vg - the amount of acid in terms of 100%, KT / Cf Ci. - heat capacity of acid, kJ / kg. gr hell Q - the thermal effect of the reaction,

  kJ / kg, K, - heat transfer coefficient, kJ / m. C,

F - heat exchange surface, m, 55 g

T, is the temperature of the cooling water, C,

T.J - temperature poured acid, C.

After that, control actions are generated on the control valve 6. At certain predetermined time intervals at, the sensors are polled, as a result of which the temperature and the pH of the reaction mass in the reactor, the concentration, the temperature and the flow rate are determined by the control computer 3

acid. Then, the current value of the volume of the reaction mass, the heat exchange surface, the new value of the acid consumption, such that the temperature of the reaction mass does not exceed the specified one, is calculated.

In the case when the pH value of the reaction mass differs from the set by 10-30%, pulsed loading starts. At the initial moment, the acid supply to the reactor is stopped — the shut-off valve 7 is closed, and the reaction mass is maintained for the duration of the stub (expander t).

Before each pulse, the amount of the reagent is calculated taking into account the concentration that is needed for the residual adjustment of the reaction mass to a predetermined pH value. It is def

It goes like this. The last seven corresponding pH values of the reaction mass and the amount of reagent supplied to this point in the reactor are remembered by the controller.

computing device. These values are approximated by a type polynomial.

40

y a + a, vx +

a, - X + a x.

where is the pH of the reaction

masses

X is the amount of reagent supplied (kg of pure substance) a, a, a, a is the proportionality coefficient.

According to the obtained dependence, using the iterative procedure, the required value of x "is calculated, so that the value of y corresponds to the specified one. After that, the reagent consumption per pulse At is determined.

 g

V v

 Mr h

 C-dt

where g is the consumption of the reagent, X d - the right amount of reagent, kg;

X is the amount of reagent supplied to the reactor before the last pulse, kg; C is the concentration of reagent,

kg / m;

& t is the pulse time, h. During the time interval between sensor polls, 1/3 of the calculated dose of acid is supplied and the reaction mass lasts for a while t latch. After that, the next sensor survey is done, a new pH value of the reaction mass is determined, the amount of the supplied acid and the new dose are calculated, and so on, until the pH of the reaction mass is set. Then the shut-off valve 7 is closed, and the next operation, which is necessary for the synthesis of sulfenamines, is performed.

yes c.

The use of the proposed method provides an increase in the quality of automatic control of batch reactors, which makes it possible to improve and stabilize the quality of the target product. Reduction of reagent tide time due to the use of pulse loading only at the final stage

Editor V.Danko Order 7749/9

Compiled by G. Ogadanov

Tehred L Oley Proofreader E.Roshko

Circulation 531 Subscription

VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5

Production and printing company, Uzhgorod, st. Project, 4

The pH of the reaction mass makes it possible to increase the productivity of the reactors without reducing the quality of the product.

Claims (1)

Invention Formula A method of automatically adjusting the pH value in a batch reactor by regulating the supply of a neutralizing agent, in order to increase the productivity of the reactor by increasing ka; The control parameters additionally measure the temperature of the reaction mass in the reactor, cooling water, neutralizing agent and its concentration, determine the required flow rate of the neutralizing apnt and supply it, compare the current pH value with the specified values and when the current pH value reaches its the first preset value, pulses the neutralizing agent with a correction in the amount of the agent previously supplied and its concentration until its pH reaches its second value. of predetermined value.