DE1458827B1 - PROCEDURE FOR AUTOMATIC CONTROL AND REGULATION OF THE PRO CESS SEQUENCE IN THE OXYGEN INFLATION PROCESS - Google Patents

Description

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The invention relates to a method for auto-carbon monoxide, carbon dioxide, oxygen and washing Control and regulation of the process sequence hydrogen, a key figure for the distribution of the acid Oxygen inflation process for freshening substances onto the re-liquid draining off in the reaction vessel carbon-containing metal in the converter actions calculated and for monitoring and even with Exhaust system in which the chemical analysis and 5 active regulation of the reaction process is used, The physical state of the exhaust gas, the pressure- In this method, an empirically determined Oxygen flow as well as the distance of the nozzle of function for the oxygen distribution, which through the bath surface continuously determined and influenced ■ further measured values can be influenced, to the overflow will. monitoring and control of the reaction process

In the case of the oxygen inflation method, the distance io is used. According to this method, however, it is not possible for the nozzle from the bath and the pressurized oxygen to regulate the oxygen flow independently of one another, that is, the distribution of oxygen per unit of time over the metal bath and the amount of oxygen blown up in the fresh vessel, the most important amounts of control gas or their effects ,
great for the metallurgical process sequence. A method for influencing the melting process, the blowing distance and the pressurized oxygen flow determine 15 in a bottom-blowing converter on the basis of the exhaust gas analysis, which is essentially the temperature and the composition continuously determined, has already become known through the gas when it hits the bath surface and the German patent specification 753 758, the depth of penetration of the Blow jet into the bath and thus the purpose of this process is to achieve a strong metallurgical effect of the blow jet. Urges, bath reduction during the decarburization period. The z. B. at high blowing pressure and short distance between the 20 measures of this process consist in the blow nozzle from the bath surface, the blow jet through equal to the determined values with empirically favorable values through the slag into the liquid metal, so determined values, the process control In addition, the decarburization of the liquid metal and, as is known, by changing the supply of wind, possibly even a reduction in the slag or in the oxygen content of the wind, takes place. Because promotes. If the blow jet cannot penetrate the slag or, in the case of bottom-blowing converters, only slightly penetrate others in advance, the oxygen of the settlement will be present, the transmission of the jet is mainly given to the slag and the proposed measures are tied to the oxygen there. inflation process not possible.

In the known methods for controlling the process sequence from Belgian patent specification 656 478 it is be in the oxygen inflation process, the amount of oxygen supplied is known by generally the distance between the nozzle and the bath- the constituents of the metal bath is bound by Surface and the pressurized oxygen flow due to the establishment of an oxygen balance from the exhaust gas Empirical values are set and can be determined at any point in time during the analysis. Through constant blowing time after subjective impressions, e.g. B. The blistering integration should be that of the individual elements master, or according to measured values, 35 total amount of oxygen set in the metal bath how the intensity of certain frequencies of the con- can be determined at any point in the process, Vertergeräusches and the like, corrected by hand. This makes the metallurgical fresh process - ins -art the melt management requires a high degree of special with regard to the end of the process - monitored should be of experience and attention on the part of the. An automatic regulation process Operating personnel and means an essential 40 or a teaching how an automatic regulation er because recognized relatively late could follow, are not in this patent specification whether z. B. the change in the distance of the blowing disclosed.

Nozzle from the bath surface too small, correct or too previously known is a method for determination is great. A complicating factor is that the effect of the end of the process in the oxygen top-blowing process a change in the distance of the blow nozzle from the 45 that by differentiating the decarburization speed bath surface and the flow of pressurized oxygen also means the decarburization acceleration is continuous from the respective state of the metal slag bath is determined (Belgian patent specification 653 544). With such as temperature, the amount of slag present, the aid of a character composition for the steel to be produced of the metal slag bath. According to a realistic decarburization curve, the final carburization case a simultaneous change in the pressure oxygen content 5 ° can be determined. An automatic regestromes and the distance between the nozzle and the bathing area is not provided.

On the surface, the situation becomes so confusing, the subject of an older German patent 1290 557

that it is no longer to be bothered by the operating personnel, as is the suggestion to control the reaction

are prevailing. Added to this is the difficulty of the process when hot metal freshening with oxygen

the distance of the nozzle from the bath surface 55 electrical conductivity of the gas atmosphere between

to be determined reasonably precisely because the filled in the electrically insulated blowing lance or a probe

The amount of metal varies from melt to melt, and the melt must be used. A simultaneous

and also the changes in the state of regulation of the amount of exhaust gas or the effects thereof

Lining the fresh vessel of different heights bath - this is also not possible,

mirror for equal amounts of metal. 60 The object of the present invention is to provide

There is already a method of monitoring and oxygen inflation in the way automatic

Control of the oxygen inflation process proposed to control and regulate that in relation to the metal

been gen (German patent application P 14 33 443.1), Urical course of the blowing process under optimal loading

in which with the help of the continuously measured and conditions runs and that at the same time the special

values transmitted to an electronic computing device 65 requirements of the exhaust system used

the pressurized oxygen flow and the exhaust gas flow, is spoken without the metallurgical course

the amount of exhaust gas discharged per unit of time, as well as to significantly hinder. Under these optimal conditions

the chemical composition of the exhaust gas on conditions one understands z. B. a short blowing time, a

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influence the metallurgical process at any point in time. The constants K and α depend on the process corresponding slag as well as the amount, the nozzle used, e.g. B. single-hole nozzle, multi-hole temperature and composition, avoiding nozzle, cylinder nozzle and the like, and the selected dimensions of ejection and over-foaming, reaching the anion of the blowing number B from. The bubble number B is a desired composition and temperature of the relationship between the oxygen distribution δ calculated from the measured values and the slag in the case of an intermediate slag, which is for the meken and above all at the end of the process. On the part of the metallurgical process sequence is characteristic, and gas system, the manipulated variables as constant as possible, ie the position of the blowing lance and the amount of exhaust gas over the entire course of the blowing process, the pressurized oxygen flow is created. Since α is often very desirable. io is small compared to χ , in many cases it is sufficient that

The invention consists in the method of the one-blowing number B in the simplified form
type mentioned in that from the continuous
Determination of two independent variables

of the process sequence, one of which is the metal B = K

urical course and the other the physical 15 ^x

Identifies the condition of the exhaust gas, derived and as

Actual values are to be represented with specified setpoints in each case. As can be seen from the equation for the blowing number B and the result of the respective process, a change has the same effect, for example the same for controlling and regulating both the doubling, the distance of the nozzle from the metallurgical course and - independently of this Bath surface has a different effect on the metallurgical process from - the loading of the exhaust gas analysis by the outflow as a corresponding change influencing both the pressurized oxygen flow and the pressurized oxygen flow.

also the distance of the nozzle from the bath top According to a further embodiment of the invention

area is used in mutual dependence according to the non-linear behavior of the Sauerwird. 25 fabric inflation process to adjust the actual value of the

This ensures that the metallurgical size for the metallurgical process sequence to the Requirements are met in the shortest possible time associated setpoint the distance of the air nozzle from can and yet the system for cooling and removing the bath surface and for adjusting the actual value dust of the exhaust gas even with a relatively small size for the physical state of the exhaust gas Size is not overloaded. The physical addition to the associated setpoint value, the pressure oxygen level of the exhaust gas also includes the changing effluent that forms. This results in a favorable, equal amount of gas, which mainly depends on the value of the pressure on the different effects of the change in oxygen flow depends. the distance between the lance and the bath

It is particularly advantageous if the size for the surface and the pressurized oxygen flow is targeted metallurgical process sequence the oxygen distribution 35 regulation of the oxygen distribution and the exhaust gas the metal slag bath as well as the exhaust gas and reached as electricity.

Quantity for the physical state of the exhaust gas Another embodiment of the invention provides

the exhaust gas heat flow or the analysis and the tem- perature, that with a change in the pressure oxygen temperature of the exhaust gas in the exhaust gas system or the flow, the distance between the blower nozzle and the steam pressure or flow above the bath in an exhaust gas cooler is changed in such a way that the actual value of the size to be used for. As a measure of the physical to the metallurgical process sequence is retained. The stand of the exhaust gas and the Kohlenstoffabbrand- with the change in pressure oxygen stream can be used vergeschwindigkeit because the MEN Thematic changing the blowing action must accordingly gene ratio of the gases CO / CO ₂ changes only slightly and not only through the blowing process and the control system, the proportion _{of CO, which burns to CO 2} 45 in the exhaust system in a regulated manner through an additional control process, predominates. The decarburization speed.

Speed can therefore be used as a measure of the amount generated in the exhaust gas. It is also advantageous if the setpoint of the size

Heat can be used. The use of the for the metallurgical process flow with the flow Oxygen distribution makes it possible to change the course of the fresh process. this makes possible very precisely to the metallurgical requirements - 5 ° an optimal adaptation to the metallurgical ore, during the exhaust gas heat flow above all demands.

when using the exhaust gas heat, z. B. for steam The change can continue in an advantageous manner

generation, interested. depending on the time and / or at least

In an embodiment of the invention is further before a variable size, z. B. the inflated seen that the simultaneous influence of the pressure 55 oxygen quantity, the bath temperature, the burned oxygen flow (dOs / df) and the distance of the carbon quantity, the conductivity between the nozzle and the bath surface in a mutual electrically insulated suspended blowing lance and the drawing takes place according to a ratio principle, with bath, the converter noise, taking place. The change in the ratio (B) according to the following equation, in which K can be set on the basis of empirical values and α mean constants, is fixed: 60. Especially when refining pig iron

with a high phosphorus content is the formation of a

= K- ^ ° ^Β Ι ^ Foam slag desired. Too high a slag

'Stand and foaming are undesirable.

Ah

The change is therefore particularly advantageous in this dependence on the conductivity between the blowing number, which expresses the metallurgical blowing effect, is roughly proportional to the oxygen distribution, electrically insulated, suspended blowing lance and / or lung , whereby disturbance variables such as bath temperature, converter noise, are both a measure for the amount of slag and the like, this relationship existed for the foamed slag.

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As a further advantageous possibility, the blowing time such as carbon, phosphorus, silicon, etc. The at the

to keep it short, without overburdening the exhaust system, reaction of the oxygen with the carbon

which is generally the limit for the size for standing exhaust gases, which are indicated by arrows 5,

the pressurized oxygen flow or the dependent thereon are collected in a gas collecting hood 6 and represents the current exhaust gas flow, the setpoint of 5 will pass through cooled gas discharge pipes 7 z. B.

Quantity for the physical state of the exhaust gas in a waste heat boiler 8. In further gas cooling systems 9

held constant during oxygen inflation. the burned exhaust gases are cooled in one

In this way, the greatest possible exhaust gas flow is deduster 10, they are dedusted. Via an exhaust

not exceeded, but during the entire blower 11, the cooled and cleaned blow-off duration will be started up. IO gases discharged.

However, it is also possible that the setpoint of the In the gas discharge pipes 7 are behind the size for the physical state of the exhaust gas in the dust extractor 10, a pressure measuring point 12, a temperature-dependence on the time or an oxygen inflation during the temperature measuring point 13 and a differential pressure point 14 changing size provided. The values of the exhaust gas measured there. This can e.g. B. for metallurgical reasons 15 stream, as indicated by arrows 15, be desirable. It is possible to use values, electronically transmitted electronic computing device 16, which change over time and / or the inflated. They serve to determine the dry exhaust gas oxygen quantity and / or the bath temperature and / or current ν.

the progress of carbon burn-up. The calculation of the oxygen distribution will change. For the speed of the coal 20 exhaust gas and bath in the converter 3 required exhaust gas burn-up - and with a constant exhaust gas flow analysis takes place, since the sampling in the converter 3 with full combustion of the exhaust gas requires considerable effort even for the CO ₂ content - a certain value to be adhered to a sampling of the exhaust gas from the gas line can be specified. pipe 7 in front of the waste heat boiler 8 through a sample path of the high speed with which all 35 take-off pipe 17. After the dedusting and drying processes take place in the oxygen inflation process, the exhaust gas sample is analyzed on carbon, the adjustment of the actual values to the target values with monoxide, carbon dioxide , Oxygen and given-the help of an automatic. In this case, hydrogen in the analysis devices 18, from where the values determined, as indicated by arrows 19, at a small distance between the blowing nozzle and the bath surface 30, some of the values determined at the beginning of the oxygen inflation, are also electrically fed to the electronic computing device 16 by a small stream of pressurized oxygen. be transmitted.

blow and only a short time after the ignition of the In the pressure oxygen line 21, which has a

The automatic blower jet for changing the movable connecting piece 20 with the blower lance 1

If the nozzle is connected to the bath surface and connected, a pressure measurement takes place at 22,

Pressurized oxygen flow switched on. As a result, a temperature measurement at 23 and a differential

the explosion pressure measurement with repeated ignition at 24. The measured values determined

like running ignition processes avoided. are, as indicated by arrow 25, the

It is advantageous if the electronic computing device 16 is transmitted electrically when it goes out. Blowing jet during the oxygen inflation they are used to determine the automatic pressure oxygen system to change the distance between the blowing nozzle 40 current d O s / dt

of the bath surface and the pressurized oxygen flow The further to control and monitor the

is switched off automatically. Conductivity values used in the process

One for carrying out the method according to the Sauer invention suspended between the electrically insulated ones The device used is in the drawing material blowing lance 1 and the metal slag bath 4, the in the form of an exemplary embodiment schematically 45 the intensity of the converter noise and the intensity shown and below on the basis of this Dar- the flame radiation at the mouth of the constellation explained. It shows verters 3 are by means of a conductivity measuring

F i g. 1 a system for steel production after the device 26, a microphone probe 27 and a

Oxygen inflation method measured with the control and pyrometer 28 and as indicated by arrows 29

Regulation of the distance between the blowing nozzle and the bath 50 indicated, entered into the computing device 16.

The distance between the nozzle and the bath surface

deten facilities and / or the position of the lance 1 is equal to 30

F i g. 2 shows a block diagram of a control device, if measured and, as indicated by arrow 31, in FIG

to regulate the oxygen distribution and the exhaust gas the computing device 16 entered,

heat flow through the position of the blower lance and 55 in the arithmetic unit 16, as from the in

the pressurized oxygen flow. F i g. 2 shows the example shown from the

Via the blowing lance 1, pressurized oxygen, the measured values of the exhaust gas and the pressure

is indicated by an arrow 2, to which the actual values for the oxygen distribution öc in an oxygen

Converter 3 located pig iron slag bath 4 and calculated the exhaust gas heat flow Q and with the

blown. The oxygen reacts there primarily compared to 60 associated predetermined setpoints,

with the accompanying elements contained in the pig iron For the oxygen distribution, the equation applies

de = - h • [0.766 • CO + 1.266 (CO ₂ + O ₂ ) -0.234 • H ₂ - 26.582].

100 d Os / d t

In this equation, öc means the oxygen exhaust gas flow, dOs / d / the pressurized oxygen flow and distribution, ν the dry, under normal conditions, CO, CO ₂ , O ₂ and H ₂ the content of the exhaust gas at ie 0 ⁰ C and one atmosphere, converted carbon monoxide, carbon dioxide, oxygen and

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Hydrogen in percent by volume. The oxygen con- By linking the blowing number B and des

division öc accordingly denotes the ratio def in the pressure oxygen stream d Ob / <$ t in the divider 36

Exhaust gas per unit of time discharged amount of oxygen a decoupling between the oxygen distribution öc

to the pressurized oxygen flow, that is to say at the ftö time and the exhaust gas downstream tiestform Q , what makes it possible for a unit of oxygen inflated onto the metal bath to change the pressurized oxygen flow without

lot. If öc = I ₅ , the entire inflated reacts to a change in the blowing effect

Oxygen with carbon and is released in the exhaust gas, which otherwise occurs through the process and the

leads. If öc <l _s , an additional control process becomes part of the inflated control system

Oxygen bound in the slag. If öc > I ₅ would have to be corrected.

more oxygen reacts than is inflated; the io at the beginning of the oxygen inflate »is with a

The excess of oxygen comes either from the low oxygen flow, e.g. B. <2 Nm ³ / Mitf. /,

Slag in which it was stored, or from and at a small distance between the blower nozzle and the bath

Metal bath or added ore. The like. Surface initiated the process and only a short one

The exhaust gas heat flow is calculated according to the equation time, e.g. B. 20 seconds after the ignition of the

j ia pale the automatic to change the distance

Q - q _c . _Ü ^ L. i ( _a + f,) , COrea + c · CO ₂ red] ^aef blowing nozzle from the bath surface and the pressure

at oxygen current switched on. The ignition can

based on the electrical conductivity between! the

calculated. In this equation, Q denotes the exhaust gas blower, which is suspended electrically insulated, and the heat flow, öc the oxygen distribution, dös / d / the ze bath, which increases upon ignition, and / or the

Pressurized oxygen flow and CÖ _re a and CO ₂ re <i the brightness in front of the mouth of the Frisehäuses

Carbon monoxide and carbon dioxide fractions in Vo and / or the exhaust gas analysis or from this

lum percent of the exhaust gas formed in the fresh vessel, calculated values can be determined. With help

the measured values determined in the exhaust pipe can also be used to calculate the extinction of the blown values. The values d and c 25 jet are determined during the blowing process,

set values for the mean sensible heat of the

Exhaust gas proportions, and the value b takes into account the process, the automatic switches off automatically, and

Heat from the reaction CO + V ₂ O ₂ -> CO ₂ . the ^1st ignition is initiated again.

In a proportional-integral-differential-'Regler Furthermore, at the beginning of the oxygen inflation (PID controller) 34 is set from the calculated actual value and 30 first for the formation of a slag, the specified setpoint value for the oxygen distribution öc < 1. For maintaining the Schläckenmönge Öc, the deviation is determined and from this the output signal is Öc = 1 and for the reduction of a slag, signal for the blowing number B is formed. In corresponding z. B. before derii Absehläcken, öc> 1 set. For example, a proportional-integral · controller determines (PI building a Schaumschläcke, z. B. in the controller) 35 from the calculated value and the 35 processing of pig iron with high phosphorus predetermined desired value for the exhaust heat flow Q content desired, accordingly initially z. B. the deviation and from this forms the output signal öc = 0.6 set. Since the Schaumschlaeke only then for the pressurized oxygen flow dOs / d /. The dephosphorus is so good, if it is so high that the determined desired value for the pressure oxygen blower nozzle is immersed, too high a level of sight and current άOs / dt is also fed into a divider 36, but foaming over is not desired given, in which, furthermore, the setpoint for öc> 1 is set from the PID controller 34 if the foaming lance B is entered and in which the square has reached the lance 1.

for the distance χ of the air nozzle from the bathroom surface The new method for control and regulation

is calculated. In one of the divider 36 after the adjustment of the distance of the blow nozzle from the

When the root eraser 37 is switched on, the setpoint value for the bath surface and the pressurized oxygen flow at

the distance χ of the nozzle from the bath surface oxygen inflation process allows the blowing process

calculated. at all times with regard to the metallurgical

The amount of exhaust gas formed for the distance χ of the blowing nozzle from the requirements and at the same time with regard to the amount of exhaust gas formed in the bath surface and the pressurized oxygen flow dCs / di fresh vessel or its calculated values trigger signals with which the 5 ° kungen optimally, whereby the actual position of the Blowing lance 1, that is to say the distance χ the distance between the blowing nozzle and the bath surface, not the blowing nozzle and the bath surface, needs to be known via a motor 32. With the help of the new valve 33 and the opening of a valve 33 for push travel, it is also possible to regulate the process to an oxygen flow in such a way that the pressure is carried out so that oxygen line 21 is arranged for given dedusting devices. 55 the oxygen inflation time is as short as possible or at

In order to have a nozzle from the bath surface regardless of the respective distance between the blower and steam generation boilers and the respective as large as possible steam generation without impairment of Drucksauerstoffstroffl disturbances such. B..Anderungen a favorable metallurgical process sequence of the metal bath and the slag in temperature is achieved. At any point in time in the process, the composition, physical nature and a suitable slag composition also amount, can be regulated equally well, is advantageously - with a relatively small amount of slag and, moreover, the non-linear behavior of the oxygen - thereby z. B. a high dephosphorization and Entauf blowing process, as achieved by the equation for the sulphurisation. Ejection and foaming is expressed by the number of bubbles B , by means of a control system adapted to this metal and slag from the fresh vessel can be largely avoided for the entire 65. In addition, before the area of the position of the blow nozzle and the pressure sacking, the slag can be largely reduced or at least close to the oxygen flow, which compensates for a low oxygen flow. consumption with a high yield of liquid metal

an optimal utilization of the process heat is made possible. In addition, the scheme adapts to everyone Disturbances, d. H. random and systematic changes in temperature, composition of the Metal and the surcharges and the changes to the fresh vessel and to a certain extent also the Air nozzles.

When commissioning a new system, it is recommended and already means a considerable amount Progress compared to the previously used processes, the blowing process by specifying setpoints for the oxygen distribution and the pressurized oxygen flow to be controlled semi-automatically by hand.

The new process can be carried out in the fixed as well as in the rotating fresh vessel will. It can also be used in the processing of low-phosphorus and high-phosphorus pig iron in the processing of other metals by the oxygen inflation process, such as. B. refining of ferrochrome-carburo alloys, can be used with advantage.

Claims (11)

Patent claims: 1. Process for the automatic control and regulation of the process sequence in the oxygen inflation process for refining liquid carbonaceous metal in the converter with exhaust system, in which the chemical analysis and the physical state of the exhaust gas, the pressurized oxygen flow and the distance between the nozzle and the bath surface is continuously determined and influenced are, characterized in that two of each other from the ongoing determinations independent variables of the process sequence, one of which is the metallurgical course and the other characterizes the physical state of the exhaust gas, derived and as actual values in each case are compared with specified setpoints and the result of the respective comparison to the control and regulation of both the metallurgical course and - independently of this - the Loading of the exhaust gas analysis by influencing both the flow of pressurized oxygen and the distance between the nozzle and the bath surface is used in mutual dependence. 2. The method according to claim 1, characterized in that the size for the metallurgical Process sequence the oxygen distribution to the metal slag bath and the exhaust gas and as The quantity for the physical state of the exhaust gas is the rate of carbon burn-off in the bath or the exhaust gas heat flow or the analysis and the temperature of the exhaust gas in the exhaust system or the vapor pressure or flow can be used in an exhaust gas cooler. 3. The method according to claim 1 or 2, characterized in that the simultaneous influencing of the pressurized oxygen flow (dOjj / di) and the distance (x) of the nozzle from the bath surface takes place in mutual relationship according to a ratio principle, the ratio (B) according to in the following equation, in which K and α mean constants: dOs / at = K- (X + 4. The method according to claim 1, 2 or 3, characterized in that to adjust the actual value the size for the metallurgical process sequence to the associated target value, the distance of the Blow nozzle from the bath surface and to adjust the actual value of the size for the physical State of the exhaust gas is changed to the associated setpoint of the pressure oxygen flow. 5. The method according to any one of claims 2 to 4, characterized in that when there is a change of the flow of pressurized oxygen, the distance between the nozzle and the bath surface is changed so that the actual value of the variable for the metallurgical process sequence is retained. 6. The method according to any one of claims 1 to 5, characterized in that the setpoint of the Size for the metallurgical process sequence is changed with the course of the refining process. 7. The method according to claim 2 to 6, characterized in that the change as a function of time and / or at least one variable variable, e.g. B. the amount of inflated oxygen, the bath temperature, the amount of carbon burned off, the conductivity between the electrically insulated blower lance and the bath, the converter noise, takes place. 8. The method according to any one of claims 1 to 7, characterized in that the setpoint of Quantity for the physical state of the exhaust gas kept constant during oxygen inflation will. 9. The method according to any one of claims 1 to 8, characterized in that the setpoint of the Quantity for the physical state of the exhaust gas as a function of time or one during of oxygen inflation is changed. 10. The method according to claim 9, characterized in that at the beginning of the oxygen inflation at a small distance between the nozzle and the bath surface, there is a small flow of pressurized oxygen is inflated and that the automatic system only works a short time after the ignition of the blower jet to change the distance between the nozzle and the bath surface and the flow of pressurized oxygen is switched on. 11. The method according to claim 10, characterized in that when the blow jet is extinguished while the oxygen is being inflated, the automatic system changes the distance between the nozzle and the Bath surface and the flow of pressurized oxygen is automatically switched off. 1 sheet of drawings