KR100765071B1 - Apparatus for controlling combustion of hot stove of blast furnace - Google Patents

Abstract

The present invention relates to a combustion control apparatus for a blast furnace hot stove, the present invention is applied to an apparatus comprising a blast furnace hot stove, a chimney and a first heater installed for waste heat recovery between the hot stove and the chimney to control combustion. A flow rate detector comprising: a flow rate detector for detecting an amount of air supplied to a hot stove; A low flow rate discriminating unit for determining whether the detected flow rate of the flow rate detector is smaller than a reference flow rate; A differential pressure detector detecting a front and rear differential pressure of the first heater; A flue differential pressure control section that calculates a control amount corresponding to a difference between the detected differential pressure of the differential pressure detector and a differential pressure with a first reference differential pressure; A high differential pressure judging unit for determining whether the detected differential pressure of the differential pressure detector is higher than a second reference differential pressure; A switching circuit unit for switching the output of the flue differential pressure control unit during low flow rate discrimination of the low flow rate discrimination section and high differential pressure discrimination section of the high differential pressure discrimination section; A converting unit converting a control amount of a flue differential pressure control unit into a valve operation amount through the switching circuit unit; A differential pressure control tube connecting front and rear ends of the first heater; It is provided in the differential pressure control pipe is provided with a differential pressure control valve for adjusting the opening ratio of the differential pressure control pipe according to the output value by the conversion unit, according to the present invention, the front and rear of the heater installed between the blast furnace hot stove and chimney When the pressure difference occurs in the stage or more than the set value, by opening the feedback connecting pipe provided in the front and rear ends of the heater in accordance with this pressure difference, it is possible to prevent excessive pressure increase of the flue side during combustion in advance to enable optimum combustion control.

Blast furnace, hot stove, combustion, control, heater, pressure difference

Description

Combustion control device of blast furnace hot stove {APPARATUS FOR CONTROLLING COMBUSTION OF HOT STOVE OF BLAST FURNACE}

1 is a schematic diagram of a conventional blast furnace hot stove installation.

2 is a time chart of the combustion control device of FIG. 1.

3 is a block diagram of a combustion control apparatus of the blast furnace hot stove according to the present invention.

4 is a time chart of the combustion control device of FIG. 3.

Explanation of symbols on the main parts of the drawings

1: heater-1 2: heater-2

3: heater-3 4: heater-4

5: heater-5 6: heater-6

7: chimney of hot stove 8: heat circulation pump for heater

9: hot stove year side 10: hot stove

11: blast furnace gas 12: Shio gas

13 combustion air 14a waste gas thermometer

14b: waste gas 15: hot stove dome thermometer;

16a: mixed gas controller 16b: mixed gas flow detector                 

16c: mixed gas control valve 17a: mixed gas detection flow rate

17b: I / V converter 20: blast furnace

21: mixed gas 22: waste gas

23: hot air 24a: low flow rate determination unit

24b: reference flow rate 25a: high differential pressure determination unit

25b: first reference differential pressure 26: V / I converter

27: I / V converter 28a: flue differential pressure controller

28b: flue differential pressure setting device 29: switching circuit

The present invention relates to a combustion control apparatus for a blast furnace hot stove, and in particular, when a pressure difference is generated in the front and rear ends of the heater installed between the blast furnace hot stove and the chimney, the feedback connection provided at the front and rear ends of the heater according to the pressure difference. By opening the tube, it relates to a combustion control apparatus for blast furnace hot stove to prevent the excessive increase in the flue side during combustion in advance to enable optimum combustion control.

In general, the blast furnace hot air furnace is installed near the blast furnace to heat the cold air (about 180 ° C.) blown from the blower to approximately 1080 ° C., accumulate this high-temperature air, and blow the air of this devised design through a blower. There is a facility to supply into the blast furnace through the blast furnace bottom.

 1 is a schematic view of a conventional blast furnace hot stove installation, referring to FIG. 1, the conventional blast furnace hot stove installation is a waste heat between the hot blast furnace 10 and the chimney 7 during the hot blast combustion. The first heater 1, which is a heat recovery equipment, is installed. The waste heat recovery is a temperature of the waste gas generated during the combustion operation of the hot blast furnace at about 250 ° C, which prevents the high temperature from being released to the outside. It is a facility for recycling heat source. The recycling of the waste gas at about 250 ° C. heats the oil contained in the first heater and sends the oil to the second heater 2 by the oil circulation pump 8 to heat the combustion air 13. It is made through a series of processes in which the blast furnace gas 11 for combustion is heated by the pump 8 to the third heater 3.

However, in such a first heater 1, clogging occurs due to waste gas generated during the combustion of a hot blast furnace, and as shown in FIG. 2, the front and rear differential pressures of the first heater are excessively increased, and the flow rate of the mixed gas is increased. This decreases, and as the pressure of the flue increases, the combustion becomes unstable, and thus, there is a problem in that the combustion efficiency is lowered because normal combustion is not achieved.

In addition, when the differential pressure is increased in the first heater as described above, the flue gas is less likely to pass through the chimney. Accordingly, the amount of the mixed gas is reduced. In this case, the output value of the mixed gas controller is increased to increase the amount of the mixed gas. The mixing gas control valve is opened up to 100%, and even if the mixing gas is opened up to 100%, unstable combustion and unstable heat storage are caused by the flow rate of the mixed gas, which causes the hot air temperature to be lower than the control value at the end of the blower. There was a problem falling.

As a countermeasure in this case, the operation has been carried out by the existing combustion control in such a state that the cleaning is stopped and the next clean water or the planned stop.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and therefore, an object of the present invention is that if a pressure difference occurs in the front and rear ends of a heater provided between a blast furnace hot stove and a chimney, the pressure of the heater is By opening the feedback connecting pipe installed at the front and rear ends, it is to provide a combustion control device of the blast furnace hot stove to prevent the excessive increase of the flue side during combustion in advance to enable optimum combustion control.

As a technical means for achieving the above object of the present invention, the apparatus of the present invention is applied to a facility comprising a blast furnace hot stove, a chimney and a first heater installed for waste heat recovery between the hot stove and the chimney to burn An apparatus for controlling, comprising: a flow rate detector for detecting an amount of air supplied to a hot stove; A low flow rate discriminating unit for determining whether the detected flow rate of the flow rate detector is smaller than a reference flow rate; A differential pressure detector detecting a front and rear differential pressure of the first heater; A flue differential pressure control section that calculates a control amount corresponding to a difference between the detected differential pressure of the differential pressure detector and a differential pressure with a first reference differential pressure; A high differential pressure judging unit for determining whether the detected differential pressure of the differential pressure detector is higher than a second reference differential pressure; A switching circuit unit for switching the output of the flue differential pressure control unit during low flow rate discrimination of the low flow rate discrimination section and high differential pressure discrimination section of the high differential pressure discrimination section; A converting unit converting a control amount of a flue differential pressure control unit into a valve operation amount through the switching circuit unit; A differential pressure control tube connecting front and rear ends of the first heater; It is characterized in that it is provided in the differential pressure control pipe and provided with a differential pressure control valve for adjusting the opening ratio of the differential pressure control pipe according to the output value by the conversion unit.

Hereinafter, a combustion control apparatus for a blast furnace hot stove according to the present invention will be described in detail with reference to the accompanying drawings. In the drawings referred to in the present invention, components having substantially the same configuration and function will use the same reference numerals.

3 is a configuration diagram of a combustion control apparatus for a blast furnace hot stove according to the present invention. Referring to FIG. 3, the hot stove facility heats air 13 (AIR) in a second heater 2 so that the blast furnace hot stove ( 10), and the blast furnace gas 11 (BFG) is heated by the third heater 3 and supplied to the hot stove 10. In the hot stove 10, the mixed gas received is heated to It blows and also contains the 1st heater 1 provided for waste heat recovery between this hot stove 10 and the chimney 7.

The combustion control apparatus of the blast furnace hot stove of the present invention applied to such a hot stove facility, as described above, the flow rate detector, low flow rate discrimination unit 24a, differential pressure detector 4, flue differential pressure control unit 28a, high A differential pressure discrimination section 25a, a switching circuit section 29, a V / I converter 26, a differential pressure control tube, and a differential pressure control valve 5 are provided.

Referring to FIG. 3, the flow rate detector of the combustion control apparatus of the blast furnace hot stove according to the present invention is installed at the output end of the second heater 2, and the differential pressure detector 4 is connected to the first heater 1. Pressure is detected at the front and rear ends, respectively, to detect the difference in pressure detected at the front and rear ends.

The low flow rate discrimination section 24a includes an I / V converter 17b for converting a detection flow rate 17a, which is a current value detected by the flow rate detector, into a detection flow rate of a voltage value, and in this I / V converter 17b. The comparator OP4 for comparing the output detection flow rate and the preset reference flow rate 24b and outputting a high level when the detection flow rate is greater than the reference flow rate, and the amplifier OP5 for inverting and amplifying the output level of the comparator OP4. It includes. Here, the reference flow rate is set to a flow rate corresponding to a time point that causes unstable combustion in advance.

The flue differential pressure control unit 28a is an I / V converter 27 for converting a differential pressure detection amount, which is a current value detected by the differential pressure detector 4, into a detection amount of a voltage value, and is output from the I / V converter 27. Comparator OP1 that compares the differential pressure detection amount with the first reference differential pressure set in advance, and outputs an error between the detected differential pressure and the first reference differential pressure, and calculates the output value of the comparator OP1 according to a predetermined equation. And an operation unit for providing the control amount MV.

The high differential pressure determiner 25a compares the detected flow rate output from the I / V converter 27 with a preset second reference differential pressure 25b and outputs a high level when the detected differential pressure is greater than the second reference differential pressure. Comparator OP2 and an amplifier OP3 for non-inverting and amplifying the output level of the comparator OP2. Here, the second reference differential pressure is set to a differential pressure corresponding to the reference flow rate of the low flow rate determination unit 25a.

The switching circuit unit 29 includes a first transistor TR1 turned on by a low flow rate determination signal output from the low flow rate determination unit 24a, and a first relay connected to a collector of the first transistor TR. XR1), the second transistor TR2 turned on by the high differential pressure discrimination signal output from the high differential pressure discrimination section 25a, the second relay XR2 connected to the collector of the second transistor TR2, and And turned on by an operating voltage provided through an always-off point PXR1 of the first relay XR1 and an always-off contact PXR2 of the second relay XR2 connected in series with the contact point PXR1. A third transistor TR3, a third relay XR3 connected to the collector terminal of the third transistor TR3, and an output terminal of the flue differential pressure control unit 28a so as to be in contact with the third relay XR3 during operation. The connected always-off contact PXR3 is included.

The V / I conversion unit 26 converts the control amount of the flue differential pressure control unit 28a into a valve operation amount through the contact point PXR3 of the third relay XR3 of the switching circuit unit, and is installed in the differential pressure control tube. (5) to provide.

The differential pressure control pipe is a connecting pipe installed at the front and rear ends of the first heater 1 to provide a flow passage of the flow rate from the rear end of the first heater 1 to the front end through the connecting pipe to relax the differential pressure. do.

Here, R, R1 and R2, which are not described in the drawing, are bias resistors, 6 are differential pressure indicators, 8 are heat circulation pumps for heaters, 9 are flue flue flues, 12 are Shio gas, 14a is a waste gas thermometer, and 14b is Waste gas, 15 is a hot stove dome thermometer, 16a is a mixed gas controller, 16b is a mixed gas flow detector, 16c is a mixed gas control valve, 20 is blast furnace, 21 is mixed gas, 22 is waste gas, and 23 is hot air.

4 is a time chart of the combustion control device of FIG. 3.

Operation according to the device of the present invention configured as described above will be described in detail below based on the accompanying drawings.

First, the flow rate detector detects the flow rate of the air 13 supplied to the hot stove and provides the flow rate to the low flow rate determination unit 24a. The low flow rate discrimination unit 24a provides a detection flow rate of the flow rate detector. 24B), the flow rate detector detects the flow rate 17a, which is the current value detected by the flow rate detector, to convert the flow rate of the voltage value from the I / V converter 17b. The comparator OP4 compares the detected flow rate output from the 17b with the preset reference flow rate 24b, and outputs a high level if the detected flow rate is greater than the reference flow rate. The output level of the comparator 24b is converted into an inverted amplifier ( OP5) is inverted and amplified and provided to the switching circuit section.

The differential pressure detector 4 then detects the differential pressure before and after the first heater 1 and provides it to the flue differential pressure control unit 28a. The flue differential pressure control unit 28a detects that the differential pressure of the differential pressure detector 4 The control amount corresponding to the difference of the differential pressure from the first reference differential pressure 28b is calculated. In detail, the I / V converter 27 calculates the differential pressure detection amount, which is the current value detected by the differential pressure detector 4. Value is converted into a detection amount, and the comparator OP1 compares the differential pressure detection amount output from the I / V converter 27 with the preset first reference differential pressure to determine an error between the detected differential pressure and the first reference differential pressure 28b. The calculation unit calculates a control amount based on a predetermined formula for the output value of the comparator OP1.

The equation is as shown in Equation 1 below.                     

Where MV is the control amount, E is the differential pressure error, P is the proportional coefficient (6.3 to 999.9%), Ti is the integral time (1 to 9999 seconds), Td is the derivative time (0 to 9999 seconds), and dt is the operator. .

On the other hand, the high differential pressure determiner 25a of the present invention determines whether the detected differential pressure of the differential pressure detector 4 is higher than the second reference differential pressure. In detail, the I / V of the flue differential pressure control unit 28a will be described. The comparator OP2 compares the detected flow rate output from the converter 27 with the preset second reference differential pressure 25b, and outputs a high level when the detected differential pressure is greater than the second reference differential pressure, and outputs the comparator OP2. The non-inverting amplifier OP3 non-inverts and amplifies the level to provide the switching circuit unit.

The switching circuit unit 29 switches the output of the flue differential pressure control unit 28a according to the output of the low flow rate discriminating unit 24a and the output value of the high differential pressure discriminating unit 25a. When the low flow rate discrimination signal output from the flow rate discriminator 24a is at a high level, the first transistor TR1 is turned on to operate the first relay XR1. When the high differential pressure determination signal output from the high differential voltage discrimination unit 25a is at a high level, the second transistor TR2 is turned on to operate the second relay XR2.

When the first and second relays XR1 and XR2 operate simultaneously in this manner, the regular off-contact points PXR1 and PXR2 of the first and second relays XR1 and XR2 become on-contact points as shown in FIG. 3. The third transistor TR3 is turned on, and accordingly, the third relay XR3 is activated so that the normally off contact point PXR3 of the third relay XR3 connected to the output terminal of the flue differential pressure control unit 28a is on contact. Becomes Thereby, the output of the flue differential pressure control unit 28a is provided to the V / I converter 26 through the always-off contact PXR3 of the third relay XR3, and by this V / I converter 26. It is converted into a valve operation amount to adjust the differential pressure control valve (5) to adjust the opening degree of the differential pressure control pipe of the first heater (1) to adjust the differential pressure of the front and rear ends of the first heater (1). Referring to the time chart of FIG. 4, the control time flow can be easily known.

According to the present invention as described above, when the pressure difference occurs in the front and rear ends of the heater provided between the blast furnace hot stove and the chimney more than the set value, by opening the feedback connecting pipes installed at the front and rear ends of the heater according to the pressure difference, combustion It is effective to prevent the excessive increase of pressure in time fluctuation in advance to enable optimum combustion control.

The above description is only a description of one embodiment of the present invention, the present invention is capable of various changes and modifications within the scope of the configuration.

Claims (3)

In the blast furnace hot stove, a chimney and an apparatus including a first heater installed for waste heat recovery between the hot stove and the chimney, the apparatus for controlling combustion, A flow rate detector for detecting the amount of air supplied to the hot stove; A low flow rate discriminating unit for determining whether the detected flow rate of the flow rate detector is smaller than a reference flow rate; A differential pressure detector detecting a front and rear differential pressure of the first heater; A flue differential pressure control section that calculates a control amount corresponding to a difference between the detected differential pressure of the differential pressure detector and a differential pressure with a first reference differential pressure; A high differential pressure judging unit for determining whether the detected differential pressure of the differential pressure detector is higher than a second reference differential pressure; A switching circuit unit for switching the output of the flue differential pressure control unit during low flow rate discrimination of the low flow rate discrimination section and high differential pressure discrimination section of the high differential pressure discrimination section; A converting unit converting a control amount of a flue differential pressure control unit into a valve operation amount through the switching circuit unit; A differential pressure control tube connecting front and rear ends of the first heater; And a differential pressure control valve installed at the differential pressure control pipe to adjust an opening ratio of the differential pressure control pipe according to the output value of the conversion unit. The method of claim 1, wherein the reference flow rate of the low flow rate determination unit Combustion control device for a blast furnace hot stove characterized in that the predetermined flow rate corresponding to the point of time that causes unsafe combustion in advance. 2. The combustion control apparatus for a blast furnace hot stove according to claim 1, wherein the second reference differential pressure of the high differential pressure determination unit is set to a differential pressure corresponding to the reference flow rate of the low flow rate determination unit according to claim 2.

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