SU1719510A1 - Method of controlling scrubbing of flues from soda-regenerating plant - Google Patents

Abstract

The invention relates to the pulp and paper industry, in particular, to methods for controlling the flue gas cleaning process of a recovery unit and improves the quality of flue gas cleaning at the exit of the recovery unit. The method includes additional measurement of volumetric flow rate, density and concentration of liquor at the entrance to the furnace space of the recovery unit, determining the flow of absolutely dry substances at the entrance to the recovery unit and the flue gas heat intensity, calculating the value of the DC voltage adjustment on the calculated value m consumption of absolutely dry matter and the intensity of heat of flue gases and by mistake adjusting the determination taking into account the measured voltages PICs direct current to the electrodes and the dust concentration and the found correction quantity specifying voltage d.c., voltage variation DC across the electrodes of the electrostatic precipitator. 1 il. cl

Description

This invention relates to the pulp and paper industry, in particular, to methods for controlling the flue gas cleaning process of a recovery unit.

The purpose of the invention is to improve the quality of flue gas cleaning at the outlet of the recovery unit.

The drawing shows a diagram of the implementation of the proposed control method

The control system contains a direct current voltage sensor 1 on the electrostatic precipitator electrodes, sensor 2 of type RM-243 dust concentration in flue gases of a regeneration unit with differential output, sensor 3 of type ИР-51 liquor volumetric flow rate at the entrance to the combustion space of the regeneration unit, sensor 4 density and sensor 5 concentration of liquor at the entrance to the combustion space of the anacon-type soda recovery unit, computing unit 6 of the BVO-11 type for calculating the consumption of absolutely dry black liquor matter, emogo into the furnace of the recovery unit, the sensor 7, the volumetric flow rate of flue gases at the outlet of the recovery unit type DC-ER1, smoke density sensor 8

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gases at the outlet of the RM-243 type recovery unit, flue gas temperature sensor 9 at the outlet of the THC type regeneration unit with converter Ш-78 computing unit 10 for calculating the intensity of heat in the flue gases at the outlet of the BWO-11 type regeneration unit, computing unit 11 for the rate of change of flow absolutely dry black liquor supplied to the furnace of the recovery unit and the intensity of heat in the flue gases at the exit of the recovery unit BVO-11, device 12 controls and the type of RLA-11, the actuator 13 controlling the voltage DC on the electrodes.

The control object consists of the soda recovery unit 14, the exhauster 15 and the electrostatic precipitator 16.

The method is carried out as follows.

The change (increase) in the magnitude of the volume flow rate signals and the concentration of black liquor at the entrance to the combustion space of the recovery unit is measured by sensors 3, 4 and 5 and is fed to the input of the computing unit 6 for calculating the flow rate of absolutely black liquor. The signal from the output of block 6 is fed to the input of the computing block 11. Where the signal from the computing block 10 calculates the intensity of heat in the flue gases at the exit of the regeneration unit, is calculated based on the readings of volume flow sensors 7, density fp 8 and temperature VAr 9 of the flue gases at the exit soda recovery unit.

In the computing unit 11, the differential dy / dt is calculated using the expression of the DC voltage reference setting on the electrostatic precipitator electrodes.

Dx ai (U $ -iEf) +, where

dt

D + "22 AG

ov

I Od Rdg Cp VAr / F; Sasv Ochshch / Ochshch x;

taff; Csd — given values of DC voltage on the electrostatic precipitator electrodes and dust concentration in the flue gases at the outlet to the environment;

I is the intensity of heat of flue gases at the outlet of the SRK

Sasv - the weight consumption of absolutely dry black liquor at the entrance to the combustion space of the IBS;

Cp is the specific heat of the flue gases at the outlet of the SRK;

F is the cross-sectional area of the economy zone at the outlet of the SRK; x is the concentration of black liquor supplied to the combustion space of the IBS;

ОМ; 05; 03; С521; ОЙ2 - coefficients of the NESTroyka;

y is the magnitude of the correction of the setting of the DC voltage on the electrostatic precipitator electrodes.

Control device 12 calculates the adjustment error Ax when comparing the current 1) Eff and preset

the values of the dc voltage values on the electrostatic precipitator electrodes and the dust concentration in the flue gases after the RMS, the magnitude of the adjustment of the dc voltage setting on the electrodes

electrostatic precipitator dy / dt and .differential concentration of dust in the flue gases of the recovery unit dk / dt from the output of sensor 2.

The control device 12 calculates the control action that is transmitted to the actuating device 13, which increases the voltage of the direct current on the electrodes of the electrostatic precipitator.

The change (decrease) in the volumetric flow rate OA, liquor density / OA and / or the concentration of the liquor at the entrance to the combustion chamber of the recovery unit, measured by sensors 3,4 and 5, are fed to the input of the computing unit 6. The calculated flow rate of absolutely dry black liquor from the output of block 6 and the intensity value of the heat of flue gases from the output of block 10 are served

to the input of the computing unit 11 for calculating the dy / dt expression of the task adjustment. The control device 12 according to the equation calculates the control error Ahi of the control action,

which is applied to the actuator 13. a decreasing DC voltage on the electrodes of the electrostatic precipitator,

Claims (1)

The invention The method of controlling the flue gas cleaning process of a recovery unit by adjusting the voltage of an electrostatic precipitator depending on the measured values of the voltage of a direct current on the electrodes, dust concentration in the flue gases at the exit of the regeneration unit, volumetric flow rate, temperature, density of flue gases and determined by these measured the intensity of heat in the flue gases at the exit of the furnace space of the co-regeneration unit, about the year and so that, in order to improve the quality of flue gas cleaning at the exit of the regeneration unit, The volume consumption of the liquor, its concentration and density, determine the consumption of absolutely dry matter and, depending on these measured values, additionally corrects the DC voltage of the electrostatic precipitator. Water liquor Evil energy The smoke