KR20030054939A - Method for Injecting Steam in Blast Furnace - Google Patents

Abstract

The present invention relates to a method of injecting and controlling steam (moisture) in order to facilitate the combustion of coke and pulverized coal charged in a molten steel furnace, and by controlling moisture in consideration of atmospheric humidity, etc. It is an object of the present invention to provide a steam blowing method in a furnace that can maintain a combustion temperature appropriately even when a large amount of coal dust is blown.

In the present invention, when the injection amount of pulverized coal is 60Ton / Hr or less, the moist blowing amount is obtained by using the following equation (1) in which the value of the balloon-ball combustion temperature (Tf) falls within the legal range of 2100 to 2250 ° C,

[Relationship 1]

Tf = [{1559 + 0.839 × BT)}-{(Blowing WH ₂ O / 1000) × 6033}]-[{(16666 × PCI) / (VB)} × 3] + [{4973 / VB × 60} O ₂ ]

The steam is blown in accordance with the moist blown amount thus obtained, and in case the blown amount of pulverized coal is 60 Ton / Hr or more, the blow required steam amount (FS) (Ton / Hr) is obtained by the following equation (3), and the blow required steam amount ( According to the FS) (Ton / Hr), the method of injecting steam into the furnace which injects steam into a tuyere is made into the summary.

[Relationship 3]

Blowing steam required (FS) = (Blowing WH ₂ O-Atmosphere WH ₂ O) × VB × 60/10 ⁶

Description

Method for Injecting Steam in Blast Furnace}

The present invention relates to a method of injecting and controlling steam (moisture) in order to facilitate the combustion of coke and pulverized coal charged in a molten steel furnace, and more particularly, to blow the coke and pulverized coal during blowing to provide an appropriate temperature. The present invention relates to a method of injecting steam into a furnace that can more accurately control the amount of steam.

In general, the operation of a blast furnace for manufacturing molten iron is a process of melting iron ore by melting iron ore and coke into a furnace and blowing hot air to produce molten iron.

In the blast furnace operation to manufacture molten iron, inexpensive pulverized coal is blown into the coke-furnace as a coke replacement furnace.

However, as the amount of pulverized coal is increased, the combustion temperature is low even when oxygen is blown in combination, resulting in the deterioration of the burnability and the unburned phenomenon.

Conventionally, the amount of pulverized coal blown is low and a certain amount of oxygen is blown and the combustion temperature is controlled by moisture.

The control of the combustion temperature by moisture in the pulverized coal blowing operation was performed by the following equation (1).

[Relationship 1]

Tf = [{1559 + 0.839 × BT)}-{(Blowing WH ₂ O / 1000) × 6033}]-[{(16666 × PCI) / (VB)} × 3] + [{4973 / VB × 60} O ₂ ]

[Here, BT: blowing temperature (° C.), blowing WH ₂ O: moisture blowing amount (g / Nm ³ ), PCI: pulverized coal injection amount (Ton / Hr), VB: blowing amount (Nm ³ / min), O ₂ : Oxygen uptake (Nm ³ / Hr)]

That is, the moisture content blowing amount in which the value of the balloon-ball combustion temperature Tf falls within the law of 2100-2250 ° C. was obtained using the relational formula (1), and the moisture content was blown in accordance with the obtained moisture content blowing amount.

On the other hand, in recent years, the operation which blows pulverized coal more than 60 tons per hour is also performed.

In this case, when the fine coal is blown more than 60 tons per hour, a small amount of moisture should be blown at a moisture control of 1-12 g / Nm ³ .

However, according to the researches and experiments of the present inventors, it was confirmed that accurate moisture control is not achieved by the above formula (1) in an operation in which pulverized coal is blown in a large amount of 60 tons or more per hour.

As described above, when a large amount of fine coal is blown, when the fine moisture is not accurately controlled at 12 g / Nm ³ or less, fine coal is not burned and is discharged to the outside or a flow path of reducing gas generated during blowing is prevented.

As a result, the reduction reaction becomes unstable due to poor breathability, which lowers productivity, and when a large amount is discharged to the outside, manufacturing cost increases due to a decrease in heat in the furnace and poor quality.

The present inventors have conducted research and experiments to solve the above-mentioned problems of the prior art, and proposed the present invention based on the results. The present invention provides a small amount of moisture by controlling the moisture more accurately in consideration of atmospheric humidity. It is an object of the present invention to provide a steam blowing method in a furnace that can maintain a combustion temperature appropriately at the time of injecting pulverized coal as well as a large amount of pulverized coal.

1 is a schematic diagram schematically showing a furnace, pulverized coal and steam blowing equipment;

Explanation of symbols on the main parts of the drawings

One . . . Furnace 2. . . Fenggu 3. . . Pulverized coal injection device

4 . . . Steam Blower

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated.

In the present invention, when the injection amount of pulverized coal is 60Ton / Hr or less, the moisture content injection amount of which the value of the balloon-ball combustion temperature (Tf) comes within the legal range of 2100 to 2250 ° C is obtained by using the following relational formula (1), and the moist injection amount thus obtained is obtained. Blows steam according to; And

[Relationship 1]

Tf = [{1559 + 0.839 × BT)}-{(Blowing WH ₂ O / 1000) × 6033}]-[{(16666 × PCI) / (VB)} × 3] + [{4973 / VB × 60} O ₂ ]

[Here, BT: blowing temperature (° C.), blowing WH ₂ O: moisture blowing amount (g / Nm ³ ), PCI: pulverized coal injection amount (Ton / Hr), VB: blowing amount (Nm ³ / min), O ₂ : Oxygen uptake (Nm ³ / Hr)]

When the amount of pulverized coal is blown over 60 Ton / Hr, the atmospheric temperature and atmospheric humidity are measured, and the atmospheric moisture content (atmosphere WH ₂ O) is obtained by the following relation (2) using these measured values.

[Relationship 2]

Atmosphere WH ₂ O = (4.953 + (0.3311 × T) + (0.0111 × T ² ) + (0.00038 × T ³ )} × M / 100

[Wherein, atmospheric WH ₂ O: atmospheric moisture content ((g / Nm ³ ), M: atmospheric moisture (%), T: atmospheric temperature (° C)]

It is necessary to blow in accordance with the following relation (3) using the wet moisture injection amount (WH ₂ O) obtained using the relation (1) and the atmospheric moisture amount (atmosphere WH ₂ O) obtained by the relation (2) in the previous step. The present invention relates to a method of injecting steam into a smelting furnace which obtains steam amount FS (Ton / Hr) and injects steam into the tuyere according to the required blow-in steam amount FS (Ton / Hr).

[Relationship 3]

Blowing steam required (FS) = (Blowing WH ₂ O-Atmosphere WH ₂ O) × VB × 60/10 ⁶

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The present invention relates to a method of blowing moisture in order to prevent combustion and to secure combustion temperature when blowing coal as coke replacement fuel in a blast furnace operation of charging iron ore and coke.

That is, the present invention is applied to a case of injecting pulverized coal below 60Ton / Hr as well as a case of injecting a large amount of 60Ton / Hr ton or more by a method of blowing moisture in order to secure combustion temperature and heat at the time of injecting pulverized coal.

Fig. 1 schematically shows a furnace and its auxiliary equipment in which a charge is charged and a state in which air volume, pulverized coal, moisture, oxygen and the like are blown into the lower air vent.

As shown in FIG. 1, the pulverized coal sent from the pulverized coal blowing device 3 is heated in the blast furnace 2 by making the air volume in the electric blower 5 during normal operation of the blast furnace 1 and reaching the air vent 2. It meets the moisture blown by the blowing device 4 and is burned in the tuyere and used as a heat source.

In the tuyere 2 of FIG. 1, the combustion temperature depends on the amount of pulverized coal, wet moisture injection amount, hot air temperature, and blowing flow rate.

The balloon-ball combustion temperature Tf in the furnace is represented by the following relational expression (1).

[Relationship 1]

Tf = [{1559 + 0.839 × BT)}-{(WH ₂ O / 1000) × 6033}]-[{(16666 × PCI) / (VB)} × 3] + [{4973 / VB × 60} O ₂ ]

In the present invention, when the injection amount of pulverized coal is less than 60Ton / Hr, the moist fraction injection amount of which the value of the balloon-ball combustion temperature (Tf) comes within the legal range of 2100 to 2250 ° C. is obtained using the relation (1). Inject steam as required.

Hereinafter, the case where the blowing amount of pulverized coal is 60 Ton / Hr or more is demonstrated.

In the case where the amount of pulverized coal is blown up to 60 Ton / Hr, first, the atmospheric temperature and the atmospheric humidity are measured, and the atmospheric moisture content (atmosphere WH ₂ O) is obtained by the following equation (2).

[Relationship 2]

Atmosphere WH ₂ O = (4.953 + (0.3311 × T) + (0.0111 × T ² ) + (0.00038 × T ³ )} × M / 100

[Wherein, atmospheric WH ₂ O: atmospheric moisture content ((g / Nm ³ ), M: atmospheric moisture (%), T: atmospheric temperature (° C)]

Next, it is necessary to blow in accordance with the following relational formula (3) using the moisture-moisture blowing amount (WH ₂ O) calculated | required using said relationship (1) and the atmospheric moisture amount (atmosphere WH ₂ O) calculated | required by said relationship (2). Obtain the steam amount FS (Ton / Hr).

[Relationship 3]

Blowing steam required (FS) = (Blowing WH ₂ O-Atmosphere WH ₂ O) × VB × 60/10 ⁶

Next, steam is blown into the tuyere according to the blowing required steam amount FS (Ton / Hr) obtained as described above to control moisture.

As described above, when steam is blown in accordance with the present invention, it is possible to precisely control the moisture to 12 g / Nm ³ or less when the powdered coal is blown at 60 Ton / Hr or more.

Hereinafter, the present invention will be described in more detail with reference to Examples.

(Example)

O₂: 15,000 Nm³/ Hr, blowing temperature: 20 ℃, atmospheric moisture: 15g / Nm³And Blowing air volume (VB): 6,100Nm³/ min) in accordance with the present invention in the operation of blowing the steam, and the operation of the pulverized coal blowing step to summarize the moisture and steam flow rate, the results are shown in Table 1 below.

Moisture Moisture Injection (g / Nm3 Moisture Blowing Amount in the Present Invention 28 26 24 22 20 18 16 14 12 10 8 6 4 2 One Blown steam amount (ton) 9.7 9.0 8.2 7.4 6.8 6.0 5.3 4.6 3.8 3.1 2.4 1.7 0.9 0.2 0 Pulverized coal injection range (ton) 45 50 55 60 65 70 Combustion temperature range (℃) 2165-2177 2148-2159 2131-2155 2127-2150 2122-2146 2120-2131

As shown in Table 2, according to the present invention, it can be seen that even if blown up to 70 tons of fine coal can maintain an appropriate combustion temperature.

In addition, as a result of controlling the moisture by injecting steam according to the present invention, it was confirmed that the combustion temperature is increased as compared with the conventional method, and it is possible to inject more than 70 tons of pulverized coal per hour without any problem in combustibility.

As described above, the present invention improves the combustion efficiency of pulverized coal and reduces fuel costs by providing a method of injecting a small amount of moisture into a smelting furnace that can maintain a combustion temperature appropriately even when a small amount of coal is blown as well as a large amount of coal is blown. Increasing cost can be reduced due to coke replacement effect, and contribute to stabilization of [Si] and [S] concentrations due to stabilization of yellowing, which not only improves quality but also reduces steam consumption.

Claims (1)

In the case where the amount of pulverized coal is blown below 60 Ton / Hr, the amount of moist blowing which the value of the balloon-ball combustion temperature (Tf) is within the range of 2100 to 2250 ° C. is obtained using the following relation (1), and the steam Blows up; And [Relationship 1] Tf = [{1559 + 0.839 × BT)}-{(Blowing WH ₂ O / 1000) × 6033}]-[{(16666 × PCI) / (VB)} × 3] + [{4973 / VB × 60} O ₂ ] [Here, BT: blowing temperature (° C.), blowing WH ₂ O: moisture blowing amount (g / Nm ³ ), PCI: pulverized coal injection amount (Ton / Hr), VB: blowing amount (Nm ³ / min), O ₂ : Oxygen uptake (Nm ³ / Hr)] When the amount of pulverized coal is blown over 60 Ton / Hr, the atmospheric temperature and atmospheric humidity are measured, and the atmospheric moisture content (atmosphere WH ₂ O) is obtained by the following relation (2) using these measured values. [Relationship 2] Atmosphere WH ₂ O = (4.953 + (0.3311 × T) + (0.0111 × T ² ) + (0.00038 × T ³ )} × M / 100 [Wherein, atmospheric WH ₂ O: atmospheric moisture content ((g / Nm ³ ), M: atmospheric moisture (%), T: atmospheric temperature (° C)] The required amount of steam to be blown by the following equation (3) using the wet moisture injection amount (WH ₂ O) obtained using the relation (1) and the atmospheric moisture amount (atmosphere WH ₂ O) obtained by the relation (2). (Ton / Hr), and the method of steam injection into the furnace, characterized in that the steam is blown into the air vent according to the required blowing amount (FS) (Ton / Hr). [Relationship 3] Blowing steam required (FS) = (Blowing WH ₂ O-Atmosphere WH ₂ O) × VB × 60/10 ⁶