RU1813821C - Black liquor combustion control method for sodium reclaming boiler operation - Google Patents

Abstract

The invention relates to methods for controlling the combustion of black liquors in soda recovery boilers operating in a cycle for the regeneration of sulphate-cellulose chemicals. The essence of the invention lies in the fact that in the method for controlling the process of burning black liquor in a soda recovery boiler, an additional measurement of the sulfide content of green liquor at the outlet of the melt solvent is made, and sodium sulfate flow rate, total and primary air flow rate, flow rate and temperature of black liquor are corrected therefrom at the entrance to the furnace of a soda recovery boiler unit. 1 ill. 1 tab.

Description

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The invention relates to the pulp and paper industry and relates to the control of the black liquor combustion process in soda recovery boiler plants operating in a sulphate-pulp production cycle.

The aim of the invention is to save sodium sulfate by improving the quality of stabilization of sulfide green liquor at the outlet of the melt solvent of the recovery boiler.

The drawing shows a block diagram of the implementation of the method.

The control circuit for implementing the method comprises a black liquor consumption sensor 1, a black liquor controller 2 based on UVM, a black liquor consumption actuator 3, a black liquor temperature sensor 4, a black liquor temperature controller 5 based on a UVM;

an actuator 6 for supplying heating steam, a sodium sulfate flow sensor 7, a sodium sulfate flow controller 8 based on a UVM, an actuator 9, a general air flow sensor 10, a general air flow controller 11 based on a UVM, a general air flow actuator 12 , primary air flow sensor 13, primary air flow controller 14 on the basis of UVM, actuator 15 of primary air flow, secondary air flow sensor 16, secondary air flow controller 17 on the base of UVM, execute the secondary device 18 of the flow of secondary air, the sensor 19 of the flow of tertiary air, the regulator 20 of the flow of tertiary air based on the UVM, the actuator 21, the sensor 22 of the temperature of the furnace, the sensor 23 of the dust ablation to electrostatic 00

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pa, a sensor 24 of the percentage of free oxygen in the flue gases in front of the economizer, a sensor 25 for sulphide of green liquor, corrective regulators: 26 - temperature in the furnace, 27 - flow rate of black liquor in the furnace, 28 - flow rate of tertiary air, 29 flow rate of secondary air, 30 - primary air flow rate, 31 - total air flow rate, 32 - sodium sulfate flow rate, 34 - the ratio of organic and mineral components of black liquor based on HCM, sensor 33, the ratio of organic and mineral components of black liquor.

The control object comprises a mixer of black liquor with sodium sulfate, an alkali heater 36, a furnace 37 and a melt solvent 38 of the soda recovery unit.

The control method is as follows.

The black liquor consumption is measured by a sensor 1, the signal from which goes to the black liquor flow controller 2 and is compared with the signal of the set black liquor consumption value, a correction signal from the regulator 27 and a signal of the current sulfide green liquor value and the control action generated by the regulator 2 enters the actuator 3, which changes the consumption of black liquor at the entrance to the furnace. A correction signal to the controller 2 is generated by the controller 27 according to information from the furnace temperature sensor 22.

The temperature of the black liquor is measured by a sensor 4, the signal from which goes to the input of the regulator 5 and is connected to the signal of the set value of the temperature of the black liquor, a correction signal from the regulator 26 and a signal of the current value of sulfide green liquor, and the generated action is applied to the actuator 6, changing heating steam flow into the alkaline heater 36. A correction signal to the controller 5 is generated in the controller 26.

The sodium sulfate flow rate is measured by a sensor 7, the signal from which is supplied to the regulator 0 and compared with the signals of the preset sodium sulfate flow rate and the correction signals from the regulators 32 and 34, and the generated control action is supplied from the actuator 9, which change the sodium sulfate flow rate .

The consumption of total air is measured by a sensor 10, the signal from which is supplied to the controller 11 for the consumption of total air and a correction signal from the controller 31 and

the generated control action is supplied to the actuator 12, which changes the flow rate of the total air. A correction signal to the regulator 11 is generated by the regulator 31 from the information of the temperature sensor 22 in the furnace, the sensor 24 for the percentage of free oxygen in the flue gases, and the sensor 25 for sulfide green liquor.

The primary air flow rate is measured by a sensor 13, the signal from which is supplied to the controller 14 and compared with a signal of a predetermined primary air flow rate and a correction signal from the controller 30 and

sensor 10 and the generated control action is supplied to the actuator 15, which changes the flow rate of primary air. A correction signal to the regulator 14 is generated by the regulator 30

according to the sensor information 23, the values of dust entrainment in flue gases.

The secondary air flow rate is measured by the sensor 16, the signal from which is supplied to the controller 17 and compared with the signal of the set value of the secondary air flow rate and the correction signal from the controller 29 and the sensor 10 and the generated control action is applied to the actuator 18, which changes

secondary air flow rate. A correction signal to the regulator 17 is generated by the regulator 29 according to the information of the dust ablation sensor 23,

Tertiary air flow rate

a sensor 19, the signal from which is supplied to the controller 20 and is compared with the signal of the set value of the tertiary air flow rate and the correction signal from the controller 28, the sensor 10 and the sensor 25 and

the generated control action is supplied to the actuator 21, which changes the flow of tertiary air.

A correction signal to the regulator 20 is generated by the regulator 28 according to the information of the sensor 23 of the dust entrainment in flue gases.

The table gives a comparative analysis of the claimed invention and the prototype, which calls for a significant improvement in the quality of stabilization of the sulfide content of green liquor at the outlet of the melt solvent of the soda recovery unit using a new method for controlling the combustion of black liquor.

Claims (1)

SUMMARY OF THE INVENTION A method for controlling the process of burning black liquor in a soda recovery Lsrtloagregat, including measuring the consumption of black liquor and sodium sulfate at the inlet of the furnace, regulating the flow of total air depending on the amount of dust removal, adjusting the flow of secondary air depending on the percentage of free oxygen in flue gases and from the flow of total air, regulation of the flow of primary and tertiary air, measurement of the ratio of organic and mineral components of black liquor, characterized in that, in order to save sodium sulfate by improving the stabilization quality of sulfide green liquor at the outlet of the melt solvent of the recovery boiler, the temperature of the black liquor at the inlet to the furnace, the temperature in the furnace, and the green sulfide value are additionally measured liquor at the outlet of the solvent melt, at the same time, the flow rate of black liquor is adjusted with a correction for the temperature in the furnace and the sulfide content of green liquor, the flow rate of sodium sulfate is adjusted with correction for the sulfide content of the green liquor and the ratio of the organic and mineral components of the black liquor, the flow rate of the heat carrier to the black liquor heater is controlled depending on the temperature of the black liquor corrected for the sulfide content of green liquor and the temperature in the furnace, and the flow rate of the total air is adjusted for sulfide green liquor, the percentage of free of oxygen and the temperature in the furnace, the primary air flow rate is adjusted with correction for the sulfide content of green liquor and the amount of dust entrainment, depending on which the flow rate of secondary and tertiary air is regulated.