JP3311233B2 - Humidity control method by blowing water into blast furnace blast - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a blast furnace by blowing water into a blast furnace by blowing water from a group of nozzles into a cool air pipe between the blower and the hot blast furnace. It concerns the wet method.

[0002]

2. Description of the Related Art When a high-temperature blast heated by a hot blast stove is performed from a tuyere provided on a bottom wall of a furnace of a blast furnace, a nozzle is inserted into a blast furnace cold air pipe between the blower and the hot blast stove to adjust moisture in the blast. Humidity control air blowing is performed to blow air to the blast furnace by blowing water from the group. Since there is a change in the moisture content in the atmosphere, by maintaining the moisture content at a constant value by controlling the humidity, airflow fluctuation factors can be reduced. The humidified air blast includes dry air blast that reduces the moisture content during air blast and humidified air blast that increases the moisture content. Dry air blowing aims to reduce coke consumption by removing the heat of decomposition of moisture before tuyeres.

Further, the humidifying air blow controls the theoretical combustion temperature and the oxidation zone in front of the tuyere to maintain the temperature of the melting zone at a constant temperature, thereby controlling the heat of the furnace. The purpose is to make blast furnace operation highly efficient by reaction. The increase in moisture increases the reaction between coke and water in the furnace, which promotes ore reduction in the furnace and suppresses these effects when shelves and slips are likely to occur in the blast furnace. is there.

Conventionally, as a method of humidifying and blowing air in a blast furnace, it has been the mainstream that steam is blown into a blast furnace cold air pipe from a blower to a hot blast furnace. However, since the energy cost of producing steam is high, a method of forming mist and blowing low-cost liquid water into a blast furnace cooling pipe as an alternative to steam is often used. Among these water blowing equipment, those using water blowing humidity control equipment composed of a combination of a plurality of shut-off valves and nozzles,
It is disclosed in JP-A-62-112715. FIG. 2 shows the water blowing humidity control equipment.

In FIG. 2, a nozzle group 2a, 2b, 2 having a water injection amount (0.5 t / h) corresponding to the minimum change in the humidity control amount is supplied to a blast furnace cold air pipe 1 from a blower (not shown) to a hot air stove.
c and a nozzle group 2d which is equal to or larger than the water blowing amount of the nozzle group,
2e _1, installing a plurality of nozzle groups with · · · 2e _n.
Nozzles constituting each nozzle group, one water conduit 3a, respectively, 3b, 3c, 3d, 3e _1, is connected to the · · · 3e _n, each water conduit 3a, in the middle of · · · 3e _n The shut-off valves 4a, 4b, 4c, 4d, 4e ₁ ,.
provided e _n, is capable of controlling the water flow alone respectively. Each water conduit 3a, · · · 3e _n is 1
It is connected to a blow-in water pipe 5 and is connected to a water tank 9 via a water flow meter 6, a water flow control valve 7, and a water pressure pump 8.

[0006] The above-mentioned water-blowing humidity control equipment has a maximum humidity control amount.
Nozzle groups 2a, 2 having a water injection amount commensurate with small changes
b, 2c and nozzle groups 2d, 2e equal to or larger than the water blowing amount
₁, ... 2e_nOf which are used for water injection
By passing water only to the group, the amount of water blown is controlled stepwise,
Perform air conditioning. For example, the nozzle groups 2a,.
_nOf the shut-off valve 4a that regulates the amount of water that can be blown from the water
0.5t / h, shut-off valves 4b and 4c 1.0t / h, shut-off valve 4
d 2.5t / h, shut-off valve 4e₁, ... 4e_nTo 5.0t / h
Then, the shut-off valves 4a,._nTable 1 shows the opening and closing operations of
As shown, when blowing more than 4.0t / h and less than 4.5t / h,
Open the shutoff valves 4a, 4b, 4d, and close other shutoff valves
And Also, when blowing 4.5t / h or more and less than 5.0t / h
Opens the shut-off valves 4b, 4c and 4d and sets the other shut-off valves
Is closed so that the amount of water blown
You. Table 1 also shows the case where the water injection rate is 5.0 t / h or more.
You.

[0007]

[Table 1]

[0008] In the above-described manner humidity control of the air blown into the conventional blast furnace, a plurality of shut-off valve 4a, · · · 4e _n
Depending on the amount of water blowing, shut-off valve 4a as a preset, opening and closing the · · · 4e _n, has a structure for controlling the flow rate of stepwise water.

[0009]

Problems to be Solved by the Invention When steam is blown into a blast furnace by using steam, and when water is used as liquid (hereinafter referred to as water)
In comparison with the case where water is blown, it is more advantageous to blow water in a mist form from the nozzle group because of the cost difference.However, in order to operate the blast furnace stably, first, the blast moisture must be maintained at the target value. Things become more important. For this reason, unless the water is accurately blown into the blast furnace cold air pipe to the target blowing amount, the blast furnace operation will be adversely affected. Therefore, it is difficult to accurately adjust the water flow rate by the control that only determines the number of stages of the plurality of nozzle groups by the feed forward as described above, and the deviation between the target value of the water blowing amount and the measured actual blowing amount is difficult. Will happen.

That is, a change in wear of each nozzle over time,
If a situation where the flow rate of water cannot be blown as prescribed due to clogging or the like occurs, the above-described conventional method does not include a means for compensating the situation. There are various problems with the conventional technology disclosed in the Japanese Patent Application Laid-Open (JP-A) No. -112715. SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the conventional technology, and in a water blowing and humidity control system for blowing water into a blast furnace cold air tube, when performing the nozzle stage number control, measures a target blast moisture content caused by a factor such as a change in each nozzle characteristic. It is an object of the present invention to provide a method of controlling humidity by blowing water into blast furnace blast, which can compensate for the deviation from the actual blast moisture obtained by the method.

[0011]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention is directed to a method of controlling the humidity of air blown to a blast furnace by blowing water from a group of nozzles into a cool air pipe extending from a blower to a hot air furnace. In the humidity control method by blowing water into the blown blast furnace, a plurality of nozzle groups including a nozzle group having a water blowing amount commensurate with the minimum change amount of the humidity control amount and a nozzle group having a water blowing amount equal to or larger than the blowing amount By providing water only to the nozzle group selected in accordance with the target water blowing amount among the respective nozzle groups, the water blowing amount is controlled in a stepwise manner, and the target water blowing amount and the measured actual water blowing are measured. And the deviation from the amount of water blown
Water pressure based on compensated water pressure deviation ΔP _W and actual water pressure P _W
According to the set value, the water supplied to the blow water pipe
And Turkey to adjust the discharge pressure is water blown by humidity control method for a blast furnace blast, characterized.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, a nozzle group 2 having a water blowing amount (0.5 t / h) commensurate with the minimum change in the humidity control amount is introduced into a blast furnace cold air pipe 1 from a blower (not shown) to a hot air stove.
a, 2b, 2c and the nozzle groups 2d, 2e ₁ ,.
Installing a plurality of nozzle groups and 2e _n. The nozzles constituting each nozzle group are each provided with one water conduit 3a, 3b, 3
c, 3d, 3e ₁ ··· are connected to 3e _n, each water conduit 3a, respectively shut-off valve 4a in the middle of · · · 3e _n,
4b, 4c, 4d, 4e _1, provided with a · · · 4e _n, has become to be able to control the water flow alone respectively,
This is the same as the conventional case shown in FIG. In addition, each water conduit 3
a, · · · 3e _n is connected to one of blowing water piping 5, blowing water piping 5 disposed water pressure gauge 10, water flow meter 6, the water pressure regulating valve 13, a water booster pump 8 It is connected to the water tank 9 through the.

In the above-mentioned water-blowing humidity control equipment, first, a target water-blowing amount _VW0 to be blown into the blast furnace cold air pipe 1 required for humidity control is calculated according to the following formula (1). V _W = {(M _SV- M _PV ) × BV × 60} / 1000000 (1) V _W : Target water blowing amount (t / h) M _SV : Target ventilation humidity (g / Nm ³ ) M _PV: water blowing before blowing moisture (g / Nm ³⁾ BV: blowing flow rate (Nm ³⁾ shut-off valve 4a, method of opening and closing combination of · · · 4e _n is
This is the same as the conventional case described with reference to FIG. 2, and in the case of the present invention shown in FIG. 1, the nozzle groups 2a, 2b, 2c having the water blowing amount (0.5 t / h) commensurate with the minimum change of the humidity control amount. And the nozzle groups 2d, 2e ₁ ,.
Of · · 2e _n, and passed through only the nozzle groups used for blowing water, blowing amount of water stepwise control, performing wet blast tone.

[0014] For example, the nozzle groups 2a, the amount of Fukikomeru water from · · · 2e _n, the equation (1) target water blown amount V _W calculated according to the 4.0t / h or more, and less than 4.5t / h familiar words, the nozzle groups 2a, shut-off valve 4a arranged corresponding respectively to the · · · 2e _n, among · · · 4e _n, table 1
As shown in (2), the shut-off valves 4a, 4b, 4d are opened, and the others are kept closed. Also, the target water injection amount V _W is set to 4.
When the speed is 5 t / h or more and less than 5.0 t / h, the shut-off valve 4b, 4
By opening c and 4d, the water blowing amount required for humidity control is set. Table 1 also shows the case of 5.0 t / h or more.

As described above, a conventional blast furnace is blown.
Control of the air flow in response to the amount of water blown during the air flow.
And a plurality of shut-off valves 4a as set in advance.
・ 4e _nJust open and close and control the water flow step by step
It was inevitably measured as the water blowing target amount Vw
Actual water injection volume V_W1In addition, the nozzle characteristics, poor nozzle
Deviation ΔV_WOccurs
You. In the present invention, such a steady deviation Δ
V_WTo eliminate the target air humidity as shown in FIG.
M_svIs input to the water blowing controller 16 in advance.

On the other hand, an air flow meter provided in the blast furnace cold air tube 1
With 14 and moisture meter 15, the air blowing flow BV and the blower moisture M _pv before blowing the water flowing through the blast cold air tube 1 measured Re Sozo, water and a blowing flow BV with moisture M _PV measured Input to the blowing controller 16. In water blown controller 16, from the measured air blowing flow BV and the blower moisture M _PV and target blowing humidity M _SV that is previously input, calculates a target water blowing amount V _W using equation (1). Then, while the input from the water blowing controller 16 the target water blowing amount V _W to the water flow regulator 11, the actual water flow rate V _W1 of the water flow regulator as measured by the water flow meter 6 which is arranged to blow water piping 5 Enter 11

In the water flow controller 11, the target water blowing amount V
_W and the excess or deficiency of water from the actual water blowing amount V _W1 Metropolitan measured calculated as water blown amount deviation [Delta] V _W, water pressure regulator as water pressure deviation [Delta] P _W required to make up for the water blowing amount deviation [Delta] V _W Enter in 12. On the other hand, the actual water pressure P _W measured by the water pressure gauge 10 provided in the blow water pipe 5
Is input to the water pressure regulator 12. The water pressure regulator 12 sets a new water pressure set value P based on the input water pressure deviation ΔP _W and the actual water pressure P _W measured by the water pressure gauge 10.
_W0 is determined, and this water pressure set value _PW0 is input to the water pressure control valve 13 provided in the blow-in water pipe 5.

The water pressure control valve 13 adjusts the discharge pressure of the water supplied from the water tank 9 to the blow water pipe 5 via the water pressure pump 8 in accordance with the new input water pressure set value P _W0. . Thereby, by compensating for the water blowing amount deviation ΔV _W supplied from the blowing water pipe 5,
Each nozzle group 2a, it is possible to compensate for the excess and deficiency of water supplied to the nozzle group selected from · · · 2e _n.

[0019] In the present invention described above, combining a plurality of nozzle groups 2a which is arranged in the blast furnace cold pipe 1 leading to the hot air oven from the blower, · · · 2e _n and shut-off valve 4a, a · · · 4e _n in addition to performing humidity adjustment blowing water Te, each of the nozzle groups 2a, the deviation between the actual water blowing amount V _W1 and the measured target water blowing amount V _W resulting from nozzle property changes in · · · 2e _n, water booster A series of cascade control loops for compensating by adjusting the discharge pressure of the pump 8 is configured.

In the case where the blast furnace blast is humidified using the conventional water blast humidifier provided in the blast furnace cold air pipe shown in FIG. 2, the actual water blowing amount V _W1 and the target water blowing amount V _{W1 with} respect to the target water blowing amount V _W. Actual blast humidity for M _SV
Figure 3 also shows the transition of _{SV1 and the} actual water injection pressure P _W1 .
Shown in Further, when the blast furnace blast was humidified by using the water blast humidifying equipment arranged in the blast furnace cold air pipe of the present invention shown in FIG. 1, the actual water blowing amount V _W1 and the target water blowing amount V _W1 relative to the target water blowing amount V _W. FIG. 4 also shows the transition of the actual blast moisture content M _{SV1 and the} actual water blowing pressure P _W1 with respect to M _SV .

As shown in FIG. 3, a conventional humidifying and blowing air to a blast furnace is used.
According to the method, the target water injection amount V _WAccording to each nozzle
Group 2a,... 2e_nShut-off valve that regulates the amount of water supplied to
4a,... 4e_nOnly open and close the supply water
Nozzle group 2a so as to be able to cope with minute changes in quantity
・ 2e_nAnd shut-off valves 4a,... 4e_nPlace and control
Actual water injection volume V_W1Is the target water volume V
_WTo some degree of steady-state deviation ΔV_WResults
Blast humidity M_SV1Also target moisture M_SVOut of the way, stable ventilation
Moisture does not occur, which hinders the reduction reaction of the ore in the blast furnace
Will be. In addition, nozzle aging and nozzle clogging
If water is generated, water cannot be blown more than in the initial state.
It is impossible to compensate for the error.

According contrary to blast humidity how to blast furnace present invention shown in FIG. 4, the target water blown quantity V _W each nozzle group 2a in response to, adjust the amount of water supplied to · · · 2e _n shut-off valve 4a which, as well as open and close the · · · 4e _n, measured actual water blowing amount V _W1, the steady-state deviation [Delta] V _W of the target water blowing amount V _W, blowing water piping 5 in water boost supply water The compensation is made by controlling the discharge pressure of the pump 8. As a result, a desired amount of water can be blown into the blast furnace cold air pipe 1 from the nozzle group. Further, even when the nozzle deteriorates over time or the nozzle is clogged, the adverse effect of reducing the amount of water blown can be overcome.

[0023]

In order to stably operate the blast furnace, it is important to keep the reduction reaction in the blast furnace constant to some extent. If the amount of moisture in the air blown into the furnace from the tuyere provided on the bottom wall of the furnace is increased, a large amount of coke and water react in the furnace, and the reduction of ore in the furnace is promoted. The opposite is true if the moisture is low. Therefore, maintaining the moisture content during the blowing to be the target blowing humidity is an important factor for stabilizing the blast furnace operation.

According to the present invention, a nozzle group having a water blowing amount commensurate with the minimum change in the humidity control amount and a nozzle having a water blowing amount equal to or greater than the blowing amount are provided in the blast furnace cold air tube between the blower and the hot blast stove. By providing a plurality of nozzle groups with a group, and by passing water through only the nozzle group selected according to the target water blowing amount among the nozzle groups, the water blowing amount is controlled stepwise, and the target water flow is controlled. A deviation between the blown amount and the measured actual water blown amount is compensated by a cascade control for adjusting a pressure of water discharged from a water boosting pump that supplies water to the plurality of nozzle groups.

Therefore, it is possible to accurately control the amount of water blown from a plurality of nozzle groups provided in the blast furnace cold air tube to the target amount of water blow, and to operate the blast furnace in which ore reduction in the furnace is promoted. Can greatly contribute to stabilization.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing a facility for humidifying and blowing air to a blast furnace according to the present invention.

FIG. 2 is a schematic explanatory view showing a conventional facility for humidifying and blowing air to a blast furnace.

FIG. 3 is a graph also showing transitions of an actual water blowing amount with respect to a target water blowing amount, an actual blowing humidity with respect to a target blowing humidity, and an actual water blowing pressure according to a conventional method.

FIG. 4 is a graph showing transitions of the actual water blowing amount with respect to the target water blowing amount, the actual blowing moisture content with respect to the target blowing humidity, and the actual water blowing pressure according to the method of the present invention.

[Explanation of symbols]

 1 Blast furnace cold air pipe 2 Nozzle 3 Water conduit 4 Shut off valve 5 Blow water pipe 6 Water flow meter 7 Water flow control valve 8 Water booster pump 9 Water tank 10 Water pressure gauge 11 Water flow regulator 12 Water pressure regulator 13 Water pressure regulation Valve 14 Ventilation flow meter 15 Moisture meter 16 Water injection controller

Continuation of front page (58) Field surveyed (Int. Cl. ⁷ , DB name) C21B 9/00 304 C21B 9/16 C21B 5/00 317

Claims (1)

(57) [Claims] 1. A humidity control method by blowing water into a blast furnace blast, wherein water is blown into a blast furnace by blowing water from a group of nozzles into a blast furnace cold air pipe between the blower and the hot blast furnace. A nozzle group having a water blowing amount commensurate with the minimum change in the moisture amount, and a plurality of nozzle groups of a nozzle group having a water blowing amount equal to or greater than the blowing amount are provided, and a target water blowing amount among the nozzle groups is provided. By passing water through only the nozzle group selected accordingly, the amount of water blown is controlled stepwise, and the deviation between the target amount of water blown and the measured actual amount of water blown is determined.
Based on the water pressure deviation ΔP _W and the actual water pressure P _W to compensate for the deviation
It is supplied to the blow water pipe according to the water pressure set value.
That water blown by humidity methods and Turkey to adjust the discharge pressure of the water to the blast furnace blast, characterized.