SU1341625A1 - Method of controlling cellulose digest process in batch-operated reactor - Google Patents

Abstract

This invention relates to process control methods. The purpose of the invention is to intensify the process. To do this, heating the contents of the reactor will hit the maximum permissible speed with both direct and deaf vapor, adjusting the final process temperature and the temperature field of the reactor. Moreover, the injection of the reaction liquid into the reactor is carried out taking into account the amount of condensate formed during the heating of the contents of the reactor. I il. (Ls

Description

The invention relates to methods for controlling technological processes, in particular pulping processes in batch reactors, and is intended for use in the pulp and paper industry in the production of pulp.

The purpose of the invention is to intensify the process for the production of cellulose.

The drawing shows an automatic control circuit for implementing the proposed method.

The drawing shows temperature sensors 1–3, cooking reactor 4, heater 5, unit 6 for calculating non-integrated temperature of the cooking space, temperature controller 7, software setter 8, actuators 9, 13, 17 and 2 5, unit 10 for calculating temperature difference between the lower and middle zones of the reactor 4, the temperature regulators 11 and 15, the temperature difference setting unit 12 between the lower and middle zones of the reactor 4, unit 14 for calculating the temperature difference between the middle and upper zones of the reactor 4, the temperature difference setting device 16 between the in the middle and upper zones of the reactor 4, the sensor 18 for the flow rate of the reaction liquid, the reaction liquid dispenser 19, the correction unit 20, the task 21 for the required amount of the reaction liquid, the averaging unit 22, the condensate amount control unit 23, the level sensor 24.

The essence of the method is as follows.

The heating program can generally be given by the expression.

f6, + k (t-t,) at to t t ;; 0 (t) I (1)

V. (t -tJnpHt, t te

where Q (.t) is the specified temperature in

time t; “1, respectively, the initial and final heating temperature;

tp,, tg are the initial and final heating times, respectively, the specified cooking end time (sides at the final temperature); K - maximum permissible heating rate.

416252.

The value of tj (and, respectively) „) is determined from the condition

f g, {trii1-ii. -tJ 5 F / n dtfn- -.)

where F is the required criterion value

completeness of the process. To maintain (t), by expressing (1) with the maximum permissible heating rate, three control loops are used. The main circuit controls the steam supply to the heater.

15 of the reaction liquid that implements one of the model laws of regulation. The most universal is PID - a law formalized by the equation

20 „/-tr.l С vj.rr,, (.) (3)

The method is carried out ... as follows.

Sensors 1 to 3 measure the temperature in the three zones of the reactor 4, the lower, middle and upper. For ease of control, pockets existing in reactors can be used to install temperature sensors in the lower cone and the circulation lines of the reaction liquid before and after the preheater 5. Signals from sensors 1–3 of temperature proportional to the measured values are directed to, block 6

calculation of the average integral temperature of the cooking space.

In block 6, the average integral temperature of the cooking space and the signal corresponding to its value are calculated, fed to one of the inputs of the cooking temperature regulator 7, to the input of the setting device 16 the temperature difference between the middle and upper zones of the reactor 4 and to the input of the setting device 12 of the temperature difference between the lower and the middle zones of the reactor 4.

The second input of the regulator 7 is given a setpoint signal corresponding to the required heating program and generated by the program setting device 8. In the controller 7, by the mismatch between the actual and set heating temperature, the value of the control signal that is directed to the actuator is determined installed on the steam supply line to the heater 5.

In order to regulate the supply of steam, the signals from sensors 1 and 2 of the temperature sensors 1 and 2 are supplied to the lower zone of the reactor 4. The temperature difference between the lower and middle zones of the reactor 4 is determined by the magnitude of which To the inlet of the regulator, 1 1 differential and temperature.

To the second input of the regulator 11, a reference signal is generated, which is formed by the temperature differential setting unit 12 between the lower and middle zones of the reactor 4 according to the average integral temperature of the cooking space. The regulator 11 generates a control action according to the size of the input signals, which is fed to the actuator 13 installed on the steam supply line to the lower zone of the reactor 4.

Similarly, regulation of the supply of live steam to the upper zone of the reactor 4 is carried out. To do this, in block 14 for calculating the temperature differential, based on the temperature data in the middle and upper zones of the reactor, measured by sensors 2 and 3, the temperature differential is determined and the signal corresponding to it is directed , to one of the inputs of the temperature differential controller 15.

To the second input of the controller 15, a reference signal is generated, which is formed by the temperature difference setting device 16 between the middle and upper zones of the reactor 4 according to the average integral temperature of the cooking space.

The controller 15 according to the size of the input signals forms the driving power. the action that serves on the actuator 17 mounted on the steam supply line to the upper zone of the reactor 4.

, The dosage of the reaction liquid into the reactor 4 by the sensor 18 is measured by its sensor 18, the signal of which value is sent to one of the inputs of the dispenser 19. The second entrance

five .

I9 dispenser signal from the output of block 20 correction. The latter forms the setpoint for the dispenser 19 based on the task 21 for the required amount of the reaction liquid and data from the averaging unit 22, about the average amount of hydrolyzate formed during the heating of the contents of the reactor 4, determined from the results of a number of previous implementations. The averaging unit 22 is connected to the condensate amount control unit 23, which, upon completion of heating, calculates the amount of condensate formed, based on the level change data in the reactor 4, measured by the level sensor 24. The dispenser 19 prepares the y value given to it; the rate is applied to the actuator 25 installed on the supply line of the reaction liquid to the reactor 4.

The proposed control method

tested under cord production conditions using an automated process control system for cord pulping.

Claims (1)

Invention Formula A method for controlling the pulping process in a batch reactor, consisting in measuring temperatures in the lower, middle, and upper zones of the reactor; and controlling the steam flow rate to the heat exchanger, which is different. the fact that, in order to intensify the process, the direct and indirect heating of the contents of the reactor is carried out with the maximum permissible speed, and the average integral temperature of the cooking space is determined and mismatching it from a predetermined value changes the steam flow rate to the heat exchanger, and depending on the corresponding temperature differences between the middle zone and the upper and lower zones of the reactor, the steam flow to the upper and lower zones of the reactor is controlled. Editor E. Kopcha Compiled by N.Nikolsky Tehred L. Serdyukova Proofreader i.Musk Order 5726 Circulation 863 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab ,, d.4 / 5 Production and printing company, Uzhgorod, Projecto st., 4