DE2026471B2 - CONTROL PROCEDURE FOR A FURNACE - Google Patents

Description

F = b ₀ + b _x T + b _z M + b ₃ M, unit: ⁰ C

b ₀ to b ₃ : coefficients and constants of the heat of reaction

M: wind humidity, unit:
g (H ₂ O) / Nm ³ (wind)

// = σ ₀ + O ₁ M + a "Oil + a ₃ Ä,
Unit: g (C) / Nm ³ (wind)
a ₀ to a ₃ : coefficients and constants

to calculate the amount of solid carbon to be gasified

Oil: injected fuel,
Unit: g (fuel) / Nm ³ (wind)
T: wind temperature, unit: ⁰ C

^ [[CO ₂ ] + [CO]} - 0.00124 M - 0.42

[N ₂

Unit: Nm ³ (O) / Nm ³ (wind)
[CO ₂ ]: CO ₂ in the furnace gas,
Unit: volume%
[CO]: CO in the furnace gas,
Unit: volume %
[N ₂ ]: N ₂ in the furnace gas,

4. The method according to claim 2, characterized in that the nominal values of F and H are predetermined according to the following formulas:

[Fj = [F] -, + A (Si- [Si 1) - f ^ r "

- [TpJ) + hAL _ __
[H] = / "/// -, -r / ι, (S / - / Si; + h ₂ (T _v

- [T _p ]) - h ₃ AL _
Si = wSi + (1-ir) S / -J
T ₁ , - wT _p + (1 - it ¹ ) 7 ',, -!

[Si]: the target value of the Si content in the liquid pig iron. Unit: weight ", ',

The invention relates to a method for controlling a blast furnace in which a product of constant quality is to be produced even in the event of rapid changes in the operating state.
To date, several methods have been known for blast furnaces. One of these methods is the so-called four-point method, where the points 0, ± 1 or ± 2 are given for each smear, corresponding to the difference between the Si content in the metal ore and its target value, which has been found experimentally.

By changing wind humidity, wind temperature or the amount of oil imported, attempts were made to bring the Si content to its target value in the event of deviations.
Various other processes are also used in the blast furnaces, for example the two-point process. Since the conventional methods control the blast furnace according to the Si content of the liquid pig iron, which is obtained with repeated tapping, the time delay is large, and a

useful operation cannot be carried out with very rapid changes in furnace conditions. the Disadvantages are similar to those of the heat level method described below appear. With this method, the disadvantages of the known methods can be more or less be balanced. Taking into account the wind temperature, the wind humidity and the injection fuel the size is called the heat level, which is calculated from the furnace gas. With The process should automatically keep the heat level at the setpoint.

The object of the invention is to control a blast furnace so that even with rapid changes in the operating state a product of constant quality is obtained in an economical manner.

This object \\\\\\ solved that the furnace state by a characteristic value F, which is characteristic of the temperature of the gas produced at the blow molding, and is represented by a characteristic value //, which is characteristic of the coke consumption, and in that at least two of the variables, namely the wind temperature, the wind humidity and the injected fuel, are controlled so that

the characteristic values F and H representing the furnace condition are kept at predetermined target values.

The setpoint values Fund H are expediently predetermined according to the temperature and the Si content of molten pig iron. They can be calculated from equations.

The control limits for the wind humidity, the injection fuel and the wind temperature can be determined.

The blast furnace thus has three control variables, namely the wind temperature, the wind humidity and the injection fuel. The properties of the Möller and the wind mass flow are also controllable, but the properties of the Möllers external conditions for the general furnace operation, whereby a homogenization can be achieved should, as the raw materials allow.

The O content in the iron ore can also be taken into account to calculate the setpoints, but the other properties are considered to be negligible disturbances in relation to the actual operation. In the control method according to the invention, since the disturbances due to slow changes are corrected (the setpoints of H and F are corrected at every tapping), no difficulties arise.

The relationships among the factors for furnace operation can all be approximately expressed by linear combinations.

All known control methods use a Bctricbskennwert approximately by a single Linear combination is expressed so that the known method only fix one of the control variables and therefore can only operate with one company size. Other company sizes are not used, so that the possibilities for an improved operating method are not taken up so that the operator's intuition and experience are inevitable got to.

An embodiment of the invention is explained in more detail with reference to the drawing.

F i g. 1 shows a schematic view of a blast furnace with the respective reaction zones above the height;

F i g. 2 is a model drawing of the reaction states in the blast furnace;

F i g. 3 shows the control mode according to the invention in a systematic block diagram:

F i g. 4 shows schematically the time dependency of the parameters;

F i g. 5 illustrates the invention schematically for the point in time when it is applied to a section or Partial control is applied.

In Fig. 1 shows the states for the respective reaction zones in the blast furnace. The furnace 1 has a furnace 3, in which a feed or a Möller such as the iron ore and the coke with Feeding devices can be fed through the small and large bells. The furnace 1 is provided with Windforrr.cn 2. The reaction zones of the Blast furnace 1 can from top to bottom in sequence in an indirect reduction zone 7, a direct Reduction zone 6, a zone with coke supply 5 and a zone 4 with tuyeres 2 can be subdivided. at In the reduction zones, the indirect reduction zone 7 and the direct reduction zone 6 have temperature ranges from 900 to 1000 C. which partially overlap each other. In connection with these reduction zones, the following is stated.

Indirect reduction zone 7

In this area the reduction reaction proceeds according to the equation

FeO ₁₁ + COh- FeO _n -, + CO ₂

the coke is not consumed and the oxygen bound in the solid is reduced. Of the Oxygen present as a solid, which is to be reduced per coke unit, is reduced.

Direct reduction zone 6

In this area the reduction reaction proceeds according to the equation

FeO + C ~ »Fe -f- CO

from, wherein the coke is used to reduce the oxygen present in the solid and the Reduction of this oxygen is brought to an end.

Zone 5 with coke supply (lower rest)

In this area, coke is accumulated, and the reduction of SiO ₂ and the heating of the liquid pig iron take place. It is ensured that the iron ore cannot fall into this zone.

Zone 4 with wind forms 2:

The wind forms 2 are arranged in this zone. The coke is made by burning coke too CO and the water gas reaction consumed. To generate a gas with a high temperature comes the thermal cracking of heavy fuel oil is also added.

In Fig. 2 are schematic the metallurgical reactions in the blast furnace, the charging (flux is omitted), i.e. the gradual outflow of coke and ore (Fe H-O) inside the blast furnace with arrows and on the other side the upflow of the wind (H ₂ O and O ₂ ) and the fuel (C ₁ H _n ) from the lower part by the tuyeres 2 shown by arrows. The complicated, metallurgical reactions that take place in the blast furnace are shown in the scheme of FIG. 2 also drawn. The upflow of CO and H ₂ is caused by the heat cracking 8, ie the reaction of O ₂ in the wind and the heavy oil, and by the water gas reaction 9, where the moisture in the wind and the coke react. Another CO upflow is generated by the coke combustion 10, namely the reaction of the O ₂ in the wind and the coke. The direct reduction 11 is the reaction of the coke and the iron ore. Furthermore, the hydrogen reaction 12 occurs, ie the reaction of the iron ore and the H ₂ gas and the indirect reduction 13, namely the reaction of the iron ore and the CO gas, which take place in the upper part of the furnace in the relationship indicated by arrows . Here, H ₂ O as a result of the hydrogen reduction 12 and CO as a result of the indirect reduction 13 are generated.

Generally speaking, the most dangerous state of blast furnace operation is the cooling of the blast furnace, what occurs when the feed reaches the height of the tuyeres, while the iron ore is not completely is reduced so that it is difficult to reduce. When the reduction is carried out, the Temperature in general. To avoid this,

the reduction and smelting of the iron ore must be completed at a level which is higher than the wind forms. In other words, apart from coke, there are no other substances than solids may be present up to the height of the wind forms. This height is shown in FIG. 1 by the height of the coke zone 5 specified.

The wind and the fuel are from the wind forms 2 in the lower part of the blast furnace 1, the Iron ore, the coke and other raw materials fed from above and the reaction zones, in this case from bottom to top, in the tuyeres 4, the coke supply 5, the direct reduction zone 6 and the indirect reduction zone 7 formed. As mentioned, a furnace can only operate under good conditions can be guaranteed if a suitable level of coke supply is maintained by the tuyeres 2 will. This means that if the coke supply is too low, the coke consumption (or gasification or the amount of coke consumed per unit amount of wind) increases, in this If the coke supply is soon exhausted, the blast furnace, as later in detail, is concerned the stabilization of the product quality is carried out, cools down. In addition, the iron ore falls if the The coke supply is exhausted, down to the level of the wind form, which makes the blast furnace controllable get lost.

Conversely, if the coke supply is too high, the liquid pig iron and slag will flow down through the coke supply, which is at a high temperature, and the rest gas with a high Temperature (the gas generated at the wind form height) flows up through the reservoir, so that this Part or space of the blast furnace for reducing the iron oxide, which is the main purpose of the blast furnace is, does not contribute. In terms of success, this means that the company is up to the exact level of the Coke supply can be carried out in a blast furnace of smaller capacity and that if part of the Oven capacity is not used, this leads to a decrease in productivity.

These phenomena greatly affect the temperature of the liquid pig iron and the reduction of SiO ₂ in the slag, which occurs gradually under the high temperature, whereby the temperature of the liquid pig iron rises to a higher value and the Si content in the slag liquid pig iron continues to increase, so that the .Wärmeinhak or the enthalpy of the liquid metal is too high. In order to avoid deficiencies when the flame temperature of the tuyeres decreases with the increase in wind humidity or decrease in the wind temperature, the coke content is increased more than in the case where the precise values are set, resulting in a high unit cost and a decrease in productivity due to the increase of the feed volume (coke) per unit of iron ore.

With regard to quality stability, the Si content and the temperature of the liquid pig iron have been used as quality characteristics of the pig iron produced for many years. With regard to the reduction of SiO ₂ , it is assumed here that when the slag flows through the coke reservoir 5, the SiO ₂ in the slag in contact with the reducing gas and the coke which have a high temperature is reduced, with the extent of the reduction is mainly determined by the temperature in the coke store5 and the residence time in it. The temperature de; The coke supply depends on the temperature of the reducing gas shortly after generation, ie the flamnite temperature F. The dwell time in the coke supply is approximately proportional to the level of the coke supply in zone 5. Since the reduction in SiO ₂ does not progress to saturation, the rate of reaction affects the Si content de; liquid pig iron stronger than the dwell time in it

ίο High temperature coke supply. However, one can simply say that the Si content is almost determined by the flame temperature F and the level of the coke supply. The speed of the Rcdukiionsreaktion slows down together with the Abis cooling, ie the temperature decrease, quickly. Since the temperature of the reaction gas decreases as it flows upwards due to the reduction of SiO 2 and other substances flowing downwards, the influence of the change in the height, ie the position of the surface of the coke store, on the Si reduction is less than that of the Flame temperature F. The liquid pig iron is heated by the reducing gas flowing in the opposite direction at a high temperature, while it flows down through the coke supply 5. The gas. that is in contact with the hot metal is finally heated to 1420 to 1460 "C. The temperature at the height of the wind forms is 2050 to 2150 C. so that there is a large temperature difference between these two points. One can therefore assume that that the temperature of the liquid pig iron is influenced more by the change in the heat exchange time, which is related to the level of the coke supply, than by the change in the flame temperature F.

It can be seen from this that to control the Si content in the liquid pig iron and to control the temperature, the level of the coke supply and the flame temperature F must be controlled or regulated. Since the height cannot be measured directly, the coke consumption H, as already mentioned, is monitored and controlled.

The calculations for the factors of the furnace condition are preferably carried out as follows, the unit resulting from I to III having the expression Nm ³ O / Nm ³ wind. It is assumed that the oxygen present in atomic form forms a gas, the volume of ^{which can be specified in the standard state (0 r} C, 1 atm).

I Direct reduction amount:
This amount is to be understood as meaning the oxygen reduced in the feed after the reaction C -s- CO.

79
(N ₂ )

{(Co ₂ ) + (CO)} -0.00124 A / -0.42

II Indirect reduction amount:

This amount is to be understood as meaning the oxygen reduced in the feed after the CO- v CO _{2 reaction.}

79
(N ₂ )

(CO,)

III Hydrogen reactant quantity:

Under this Menac is the one in charge

sound reduced oxygen after the reaction IL, -> Understanding ENT.

79

(Ho) + 0.00124 M I 0.00134 oil

IV Hamm temperature at the tuyeres in ^C C:
For the approximate linear combination for the flame temperature at the tuyeres, the R amm equation results in a value used in normal operation from the wind moisture M, the injection fuel oil and the flasher temperature Γ:

F : - = Z) ₀ -! - b _x T - \ - KM -: - b-fil

/>"To/>., Are constant coefficients
The values chosen in a practical embodiment of the invention are:

H ₀ ----- -1410, b _t = 0.94, />"= -6.2.

b _{: t} = -4.6

This equation was used at the time the furnace was controlled, the mean wind temperature being about 100 ^: C., the mean wind humidity about 25 g / Nm ³ , the mean amount of heavy oil blown in about. 38 g / Nm ³ and depend on the operating conditions.

V coke consumption in g C / Nm ³ wind:

The weight of the gasified carbon per Nm ³ wind results in see

H = a ₀

a _z oil -τ- a- _} \

O _x

n ₀ to α- are constant coefficients for calculating the amount of solid carbon gasified by the reaction. The values chosen in the above practical embodiment are
O ₀ = 225. O ₁ = 0.667, O ₂ = -0.866

These values change depending on the carbon content in the fuel. The value -0.866 applies if heavy fuel oil with a carbon content of 86.6% is used. 45 indices

35

40 [H ₂ ]: H ₂ ";, in the furnace gas (usually 4 to 5%) This value is measured continuously with a heat-conducting gas analyzer and also fed into the computer at minute intervals, the signals being converted into direct current.

[N ₂ J: N, volume- ⁰ , ', in the furnace gas

= 100 - [CO ₂ ] - [CO] - [H _s ]

after which the calculations per 1 minute in

Computer.

M: wind moisture in g ll ₂ O / Nm ³ wind

15 to 45 g / Nm ³ are usual. It is measured continuously with a lithium chloride hygrometer, the measured value is entered into the computer every minute and the signals are converted into direct current.

Oil: Heavy oil in the wind in g oil / Nm ³ wind
C content 86.6% by weight
15 to 45 g / Nm ³ are usual. Measurements are made continuously with a rotary meter, the value is entered into the computer every minute, the signals being converted into direct current.

T: wind temperature in 'C

1000 to 1200 ° C are common. It becomes continuous measured with a thermocouple, the values every minute into the computer, whereby the signals are converted into direct current.

O / C: ratio of iron ore to coke

3.2 to 3.5 are common, the target values are entered into the computer and the iron ore and the coke charged to the furnace with this actual ratio exactly brought in.

Weight of oxygen in iron ore (at the time of loading)
Usual value: 30 to 40%. The O content is entered separately in the calculator depending on the types of iron ore and the feed ratio.

α. _Λ - 536

VI Content of bound oxygen in the direct reduction zone in gO / Nm ³ wind: The oxygen is contained in the feed that falls from the indirect reduction zone into the direct reduction zone, and is given as oxygen in weight units in the part to be reduced that passes through the wind unit volume is treated.

L = H (OiC) -, O ₁ -, -714 (β-, ^ - yj)

(CO _n ]: CO.% In the furnace gas (usually 16 to 19%)

[CO]: CO% in gout teas (usually 21 to 24%)

The values are continuously analyzed and measured with an infrared gas analyzer and fed into a computer every minute, the signals in Direct current can be converted. Finheit is the dry base volume in%.

-1, -2: -1 shows the mean value 3 to 6 hours ago, -2 the mean value 6 to 9 hours ago. at In the furnace according to the invention, it takes 6 to 8 hours for the load to reach the furnace floor reached by the gout. Accordingly, -1 shows the dwell time in which the feed currently in the direct reduction zone in was the indirect reduction zone, and -2 was the feed period.

The mean values are indicated in the usual way by overlining.

The coke consumption // is adjusted so that, if the Si content during tapping (the sample of liquid pig iron is analyzed with an optical spectrometer) and the temperature of the liquid pig iron T _p (measured with the immersion pyrometer or the two-color pyrometer ) have been checked, these values are fed into the computer in order to calculate the values to be set for H and F, ie the target values H and Γ according to the following equations. Since parting every 2 to 3 hours

609 536/201

occurs, the following calculations are also performed every 2 to 3 hours.

[HJ = [HJ- ^ h ₁ (Sl- (SiJ)

+ Ih (Tp- [TpJ) -Ii ₃ AL (1)

(2)

IF] = [F] - _X —MSi- [

-Iz (Tp- [TpJ) + u

Si = wSi + (1 - n) S / -,
Tp = itTp -r (1 - "■) 7p-,

/ 5/7: Target value of the Si content in liquid pig iron in% by weight. A common value is 0.55% in a blast furnace.

[TpJ: According to the invention, the nominal value of the temperature in "C" of the liquid pig iron should be 1450 "C in the furnace.

hi: coefficient

//: coefficient

These coefficients /// and // can be found by compiling the relationships between the values such as //, F, Si, Tp and AL from previous furnace operations under good conditions using statistical methods, for example with multiple regression analysis or through experience.

[HJ- ₁ : target value of H up to this point in time.
[FJ-i '. Setpoint of F up to this point in time.
AL: change from L.

L: content of bound oxygen in the direct reduction zone in a O / Nm ³ wind L = // (0 / CV ₂ O _x - _t - 714 (/ Jl ₁ - j / -,)

H: Coke consumption in g CNm ³ wind

O / C: ratio of iron ore and coke in the Furnace given loading.

0 ^: oxygen in% by weight in iron ore

ß-i

}> _ ,: Indirect reduction and hydrogen reduction quantities Nm ³ O / Nm ³ wind, which are present in the indirect reduction zone of the furnace, based on the charge, as expressed by the factor equations II and III.

By omitting the long-term and medium-term (more than 12 hours) fluctuations in the Si content and the temperature T _{p of} the liquid pig iron and by avoiding the furnace cooling as a result of the abnormal drop in the level of the coke supply, the target values for coke consumption H and the flame temperature F to be operated on. The short-term (less than 12 hours, in particular a few hours to hours) fluctuations are reduced by keeping H and F at the target values [HJ and [FJ.

The level of coke supply is affected not only by coke consumption but also by changes in the levels of coke and bound oxygen in the feed falling down from the top. The fourth term (- li ₃ AL and + / ₃ / lL) of the above equations 1 and 2 correct or improve the influences on the height of the coke.

Numerical examples for the determination of [UJ and (FJ are:

example 1

[H] = / 77 / -, -I- 0.500 (Tp - [TpJ) -QJSAL [F] = [F] -, - 530 (Si - [SiJ) + 0.42JL

Example 2

[Hj = [HJ-1 τ 40 (57- [SiJ)
+ 0.500 (7 ^ - [TpJ) - 0.75 JL
[FJ = / T7-, -530 (57- [SiJ) - (% - [TpJ) + 0.300 JL

Furthermore, according to the invention, the blast furnace should work in such a way that productivity is improved and unit costs are reduced. The coke consumption / 7 in g C / Nm ³ wind and the flame temperature / ■ "in C are calculated according to the following equations,

as already mentioned under IV and V:

// - = -. 225 -r 0.667 M - 0.866 oil - _r 536> (3)
F = 1410 - \ - 0.94 T - 6.2 M - 4.6 oil (4)

M: wind moisture in g H ₂ OZNm ³ wind
Oil: injection heavy oil in g oil / Nnv ¹ wind
T: wind temperature in "C

λ: directly reduced oxygen concentration in Nnr ¹ O Nnr ¹ wind

The wind moisture Λ /, the heavy oil injection oil and the wind temperature T on the right-hand side of the other equations 3 and 4 can be controlled, but the direct reduction λ is not, in order to ensure reliable operation and quality stability, so that the values of equations 3 and 4 can be kept at the setpoints that are obtained from equations 1 and 2, M, "oil" and 7 are controlled according to the changes in the direct reduction

tion λ.

In the blast furnace used, the direct reduction λ changes between 0.130 and 0.170 Nnr O / Nm ³ wind, with the shortest fluctuation cycle several minutes and the longest cycle several minutes

Takes hours.

Since the two variables H and F are controlled with the three variables M, "Ö /" and T for the setpoints [HJ and JF] , each of them can be determined as desired. The wind temperature T is at dei

According to the invention, the definition of these three variables is kept at the permissible maximum, whereby one achieves that the amount of heat otherwise generated by the expensive coke is partly due to the combustion cheap blast furnace gas or coke gas is replaced, se

that the unit cost of the product can thus be lowered, and the iron ore and dei Coke is added reduced by the volume that would have been required if the coke had not been added would have been replaced, thereby providing an improvement in productivity.

If the wind temperature T is kept at the maximum permissible temperature, the values for the heavy oil injection have "Ö /" and the wind humidity

M also has a maximum value when controlling Jl and / 'to the setpoint values, which can be seen from the designations of the coefficients in equations 3 and 4. In this way, the oil, which is cheaper than coke, is consumed with the maximum allowable amount, which increases the amount of carbon from the tuyeres and decreases the amount of coke in the feed, which reduces the finances of the product and improves productivity, similar to increasing the wind temperature T.

By fixing the wind humidity M to the maximum permissible, the reducing gas is obtained from the humidity at the height of the wind nozzles after the water gas reaction

Minute must be smoothed in order to get the action values M _ac , Ö / “ _t and T ₁₁ , - .

Ma, - -M "p \ έ Λ Mo M _n , - Mbcr \ - ■ - min
Mac S Mn:

\ Ölac— Ölap \ < .10 /,

\ Oil "c - Öker \ - min

Ölac S ÖluG Tac - T _O p < J Tog

Tac - Tier = min

Mac

Oil lac

Tac

H ₂ O + C - H ₂ -; - CO

thereby reducing the amount of gas in the rest gas increases, and consequently accelerates the Rcduktions- and reaction rate, which in turn do to an improvement in productivity. However, the water gas reaction consumes coke. The setpoint M of the wind moisture M is therefore set accordingly. since low financial costs are required in production rather than productive improvement.

The wind humidity Λ /, the heavy oil blowing »oil« and the wind temperature T are calculated in practice as listed below. First, the amount of oxygen that is directly reduced is calculated using the following equations from the gouty passages of CO, COo and H ₂ and the wind light, once per minute:

79

₂ ] - O, OUi24 M

-0.42Nm ³ OzNm ³ wind

[N ₂ ] ^ 100 - [CO] - [CO ₂ ] - [H ₂ ] ""

Then the first target value (calculation value) Ai)., R. Oil ,,, r and Thcr of M. »Öh and T according to the following linear program calculation [LP) each calculated once per minute.

Evaluation function: Ti, _cr - max.

Boundary condition:

[H] = 225 4- 0.667 M _ber - 0.866 Ö / _{b (T} - 536 λ
[F] = 1410 + 0.94 TBER - 6.2 M _calc - 4.6 Oil _BRR Mber i = Mog, oher Si Oloc, Animal S Tog

Mog, ÖloG and 7Oc are the upper limits of M, Öl and T.

In this connection, [H and [F 'are obtained by Equations 1 and 2. However, H is in /. contained in the fourth term on the right for the calculations of [H [ and [F] . Also, since // is not always set exactly to [H '' , the values of [H] and [F ^: spontaneously vary a little.

The values for M _ber , Ö / _ber and Tficr obtained from LP include the negligibly small fluctuations or errors of the measuring instruments. so that M, oil and T by the following calculations each M "p, oil" p and Top are the earlier operational values of M, oil and 7 *.

The mean values from one hour before 0 ^ 1 hour are stored in the computer in order to use them in the present case.

Mn, -, Öh <; and Ti; q are the lower limits of M. Oil and T.. 1 Md,;, . i Öloc and .1 Toc are the permissible maximum deviation widths between Mi, rr, Öhr ?, Thcr and M "p, Ölov, Top. For the blast furnace used, the values are usually for. I M ₀ ,; - 5 g / Nm ³ . . I Öloc - 5 g / Nm ³ and. 1 T " _(: ---- W C. These calculations are made to avoid extreme increases in M, Oil and T due to partial abnormalities in the furnace, computer or measuring instruments, such as increases, decreases or rapid changes in the Avoid values.

The upper and lower limits of M. "() /" and 7 are fixed, with the technical conditions are taken into account with regard to the Vorricntungskapazitäten The borders are ⁿ the usual S annuniisbereichen exactly the same. The actual operations

4 "of the action _values of Λ / ηΓ. Oil _a , and T ₀ , - are achieved by automatic setting of the specified parameters of the control devices, which are generally used in conventional blast furnaces, through electrical signals from the computer.

Such control instruments are used in process engineering in the production of iron. Steel and Petroleum widespread and no special facilities.

The ideal control is that Mi, _rr . Uh, _ej

and Tber almost equal Clear, Oil _ar and T _ac and also the setpoints [M], [Oil] and [T [ are. If the values of Mber, Öker and T _b er_ are above the upper and lower limits of Mog, ÖIog. Tog, Wed ₀ , eye. and Tig go out, the blast furnace cannot be directly controlled because the above-mentioned four objects are to be achieved.

The coefficient -38 relating to the wind moisture M is obtained from the amount of carbon. which is consumed per unit of moisture content by the water gas reaction. The coefficient - 4C relating to the heavy oil injection is obtained from the amount of carbon. which is blown in per unit of content of the heavy oil injection. The coefficient standing at the wind temperature - 4 is obtained from the amount of carbon that is required for the case. that the heat capacity from the wind temperature IC of the unit volume is generated by the combustion of C - * CO.

13 I 14

As mentioned above, the setpoints of [M], each set externally in the eighth computer C8, [Oil] and [T] of the wind humidity M, the difficulty in determining the difference between the calculated oil injection »Öh and the wind temperature T for the and the setpoints received in order to give an AC _ac to the BeHochofen set to a value that is as large as the service for the batches,
is possible, while [M] is then as small as possible 5 F i g. 4 shows the hourly values at a practical level when reducing the unit table trial. [Q] aimed at cost on the left. shows, follows the conventional heat level

The furnace can move about the wind humidity M, the. M _be r is the calculated result, and M _op heavy oil injection "oil" and the wind temperature T, is the actual operational value for it. Mb _er , Öl _ber , more precisely controlled by M _ac , Öl _ac , T _ac and AC io 7W from [HF] are desired, calculated results, which at the same time ensure reliable results. The actual drive to work determined from this, a stable quality and a reduction in the values are shown as Mac, Ölac, T _ac . M _op , Öl _op , T _op Unit costs as well as an improvement in the produc- tion show the control with an operator according to tion through optimal continuous and automatic the known method. The well-known method of controlling the furnace is taken care of. 15 usually does not work with the oil injection * Öh

F i g. Fig. 3 shows the concrete control system of the furnace and the wind temperature T so that their values are as

according to the invention. The setting values for the raw straight lines appear. The tempe-

materials are entered into the first computer Ci , temperature T _v and the Si content of the liquid pig iron

so that the oxygen content O _x in the iron ore can be compared with the above operating values.

receives. This oxygen content O _x and O / C and the 20 carry. If you have any of the operational changes with

indirect reduction /? are appropriately compared to these lowest changes, it becomes clear

before storing in the third mentioned later that the values for M _a c, Ölac, Tac according to the invention

Computer C3 entered into the second computer Cl , which are the most suitable. The under the present

so that you have the content £ of bound oxygen invention carried out investigations

in the direct reduction zone. This value 25 also shows that conventional furnace operation is one

is in the fourth computer CA along with which has quite a long operating period under conditions

Si content of the former liquid pig iron and where there is either too much or too little coke.

the preceding temperature T _{p of} the liquid raw material For the in FIG. 4 simulated simulation methods

given iron. the values for actual operation are shown in

The setpoints [Si], [T _v l and the coefficients / 7 /, 30 converted mean values for one hour, which were determined as loading / 7, which were taken from the previously determined phase investigation and the operating values of the just preceding stage, are entered in C4 . Further to the control values for the next hour, the earlier saved values of H will be calculated. Operating data determined in this way and the control and F values from a fifth computer C5 are shown in FIG. 4 recorded. Calculates the setpoints [H] and [F] , which are entered in the computer directly connected to the furnace, this sixth computer C6 , which calculates the control values per minute, whereby an automatically desired amount for the wind humidity Mber, Operation per 1 minute is possible, while the pro blow fuel Öhcr and wind temperature T _{calculated over} 1 minute are calculated as mean values for. _{The CO 2} , H 2 values obtained from the gout, converted for 1 hour and printed out on a strip of CO _{2, H 2,} are printed out in the third computer C3. On the basis of this strip is the heir. The values for "oil" are also included in this calculator. 4 made. Such a calculation and Λ /, which is converted into analog signals via a heavy oil regulator or every 1 minute, control unit Ö // RC and the wind humidity display so that the recorder or recorder continuously and control device MRC receives it, as well as the value T , borrowed can register.

the one of the temperature control device TRC ER- 45 at a suitable time it is input to the on-line holding, so that the direct reduction is λ, connected in control, so that good results β indirect reduction and obtains the Wasserstoffreduk-. The target values [Si], [T _p ], [M], [Oil] and [T], ticn γ can be determined. The Si content in the liquid pig iron obtained in this way, the direct temperature reduction, is entered into the fifth computer C5 temperature T _{p of} the liquid pig iron, the wind moisture M , in which the values of M, i> Öh, T, 5 ° of the heavy oil injection "Oil" and the wind temperature which control the deviation widths with the earlier of the heavy oil injection "$ /" and the wind temperature values are also given by the control unit, which are required for this calculation, so that the earlier RMS values and external variables obtained from H and F in the case of the invention. These values H and F (which are previous methods are the mean values of the actual and instantaneous) are set equal in the 55 loaned operations and are 0.595% given fourth and sixth computers CA and C6, respectively. 144O ⁰ C, 25.8 g / Nm ³ , 38.0 g / Nm ³ or 1200 ⁰ C (the upper limits Af ₀ C, ÖIog, Tog with respect to M, mean value of the actual operation was 1150 ° CfT ¹ , » Oil «, T are set externally in the computer C6, but set to 1200 ^° C.). So the simulation allows you the values for Mber, Oelber, T gets _over that therefore the judgment whether Verdurch the invention [H], [F] //, F were calculated. These 60 drive overall better operation enables values are introduced into the eighth computer 8C. as the known method, which is controlled by the wind The lower limits Mug, ÖIug, Tug and Λ /, Öl, T humid M and mainly on which are set externally in the seventh computer Cl , the heat level model is based, while the heavy oil is based on its deviations to limit. The action values T _ac , oil _ac , M _ac obtained on this injection of "oil" and the wind temperature T approximately were kept at the mean values mentioned,
on the respective control devices TRC, Oil-RC and MRC. If the method according to the invention is actually given, where the control actions for the furnace are applied to the blast furnace operation, one can be A-irkt. The setpoints [M], [Oil], [T] will consider it in such a way that the furnace, as shown in FIG. 5 ge

/ ίο

shows is divided radially, the invention being applied to each of these divisions. Both The movements of the coke supply and other substances are not large in the blast furnace always evenly, even at the same height. In

In such a case, the method according to the invention is carried out in practice according to the method shown in FIG. 5 shown Idea of division implemented in order to achieve good results. The tapping outlets are on the dividing lines intended.

For this purpose 4 sheets of drawings

Claims (3)

Patent claims: 1. A method for controlling a blast furnace, characterized in that the furnace state is represented by a parameter F, which is characteristic of the temperature of the gas generated at the blow molds, and by a parameter H, which is characteristic of the coke consumption, and that at least two of the variables, namely the wind temperature, the wind humidity and the injected fuel, can be controlled in such a way that the characteristic values F and H representing the furnace condition are kept at predetermined target values. 2. The method according to claim 1, characterized in that the setpoints of F and H are predetermined according to the temperature and the Si content of the liquid pig iron. 3. The method according to claim 1, characterized in that the characteristic values F and H are predetermined according to the following formulas: [T ₁ ,]: the setpoint of the temperature of the liquid pig iron, unit: ⁰ C w. smoothing weight value A ₁ to A ₃ : coefficients A to / _s : coefficients [H] - ^ ₁ : Setpoint of H up to this point in time [F] -I-. Setpoint of F up to this point in time AL: change from L L: Content of bound oxygen in the direct reduction zone in g (O) / Nm ³ wind