SU1047962A1 - Device for monitoring metal temperature in converter - Google Patents

Abstract

1. DEVICE FOR MONITORING THE METAL TEMPERATURE IN THE CONVERTER, containing an electrode, a current meter, a power unit, a computing unit connected to the metal temperature indicator, which is, in order to improve the accuracy of control It additionally contains an electrode mounted in a metal, a contact potential difference meter, a control unit, and three memory blocks, the inputs of the contact potential difference meter being connected to the electrodes installed, respectively. The socket is also in metal, and the output is at the input of the control unit, to which the outputs of the current meter and the power supply unit are also connected, in addition, the outputs of the control unit are connected to the computing unit and to iz-. The contact potential difference measurer directly and through a current meter, as well as, respectively, through the first, second and third-party memory blocks, is connected to a computing unit, which is connected to the input of the control unit. 2. The device of claim 1, wherein the computing unit contains four cyMTvjHpoBaHHH nodes, four multiplication nodes, two functional transformation nodes, division nodes, delays and a compensating transformation, the output of the first summation node through the first the multiplication node is connected to the input of the second suction node, the input of which is additionally connected via the second multiplication node and the first functional conversion node to the compensating conversion node, and the output of the second node sum 1 "is connected to the input of the evil division, to which, besides, what, the second level of the functional extension unit of education - and the third node of the spanning are connected the outputs of the third and (L of the fourth multiplication nodes, the outputs of the division node are connected to the fourth summation node and - a compensating transformation, into its own sequence, one | 1n output of which is connected to the fourth summing node via a delay node, and the other output is directly connected to the second multiplication node. 3. The device according to claim 1. The control unit contains the node AND, the node NOT,: a timer and a time relay with eight contacts, the TIME INPUT of the time relay through the timer and the node AND connected to the output of the node NO, the inputs of the second and fourth time relay contacts among themselves, inputs of the third and fifth time relay contacts are interconnected, outputs of the second and third time relay contacts are interconnected, outputs of the fourth and fifth time relay contacts are interconnected, inputs of the sixth and seventh contacts of the relay are interconnected a.

Description

The invention relates to temperature control of a converter process and can be used in open-hearth and electric arc furnaces. A device for controlling the temperature of a metal in a converter is known, which contains a thermocouple installed in the unit lining below the level of me-. tall, - and fitted with protective tips 1. It is also known to introduce a thermocouple into the unit using a special thermal probe 2. The devices have a short service life (3-4 melts), due to the low resistance of the protective tips or low accuracy due to the heat outflow along the tip and lining. When using a thermal probe, the control accuracy is reduced due to the large temperature gradients of the bath during the purge, besides it is impossible to ensure continuous measurement in this case. Closest to the invention is a device for monitoring the temperature of a metal in a converter, containing an electrode mounted in another torch, a current meter, a power supply unit, and a computing unit connected to the pointer. The measurement is made in the probe-ground gap. The electrical conductivity of the Torch is (according to Ohm's law) according to the magnitude of the electric current flowing through the interelectrode gap, and the applied voltage 9 The Ohm law for plasma is performed only at small voltages between the electrodes in the initial straight-line portion of the current-voltage characteristic. At voltages that are more critical, the current through the plasma does not depend on the magnitude of the applied voltage, i.e. It reaches saturation up to the voltage at which breakdown occurs in the gas and the discharge is ignited. Thus, in the prototype, the current through the plasma is measured at the initial, straight line portion of the current-voltage characteristics of the interelectrode gap, i.e., at voltages lower than stress, characteristic of the regime of value. The device has low accuracy due to the fact that the electrical conductivity of the plume (the magnitude of the current and voltage on the straight line section of the volt-ampere characteristic) is ambiguous due to the temperature of the metal, because, in addition to the temperature of the metal, the electrical conductivity is influenced by the decarburization rate and slagging mode. The purpose of the invention is to increase the accuracy of the control. The goal is achieved by the fact that the device for controlling the temperature of the metal in the converter, containing the electrode, current meter, power unit, computing unit connected to the metal temperature gauge, additionally contains an electrode installed in the metal, contact potential difference meter, control unit, three the memory unit, the inputs of the contact meter, the potential differences connected to the electrodes, are installed respectively in the torch core and in the metal, and the output is connected to the input of the control unit to which The outputs of the current meter and power supply are also connected to it, in addition, the outputs of the control unit are connected to the computing unit and to the contact potential difference meter directly and through the current meter, as well as through the first, second and third memory units, respectively, to the computing unit connected to the input of the control unit. The computing unit contains four summation nodes, four multiplication nodes, two functional transformation nodes, division nodes, delays and a compensating converter, the output of the first summation node through the first multiplication node is connected to the input of the second summation node, the input of which is also connected through the second node multiplication and the first functional transformation node with the compensating transformation node, and the output of the second summation node is connected to the input of the division node, to which, in addition, The second functional transformation node and the third summation node are connected to the outputs of the third and fourth multiplication nodes, the outputs of the division node are connected to the fourth summing node and the compensating conversion node, in turn, one output of which is connected to the fourth summing node through the delay node, and the other output is directly connected with the second multiplication node. The control unit contains an AND node, a NOT node, a timer and a time relay with eight contacts, the time relay input through a timer and the AND node connected to the output of the NO node, the inputs of the second and fourth time relay contacts are interconnected, the inputs of the third and fifth relays time is interconnected, the outputs of the second and third time relay contacts are interconnected, the outputs of the fourth and fifth time relay contacts are interconnected, the inputs of the sixth and seventh time relay contacts are interconnected. The device is based on the determination of the current of thermionic emission from the surface of the molten metal, the magnitude of which is related to the temperature of the metal, and the work function of the electrons. Measurements of conductance in saturation mode between the electrode and metal at. The positive and negative voltages at the electrode allow us to determine the thermal emission current from the metal surface, and the measurement of the contact potential difference between the electrode and the metal allows us to determine the electron work function from the metal surface during purging. The electric current in the flame of the oxygen converter is due to the presence of ionic and electrons in it. In the lower ion mobility compared to electrons, the conduction current in the saturation mode is limited by the ion component of the plasma current. . When the voltage on the electrode is negative relative to the bath, the saturation current 1 is equal to 15.-2b:) and where I is the saturation current with neg. voltage on the electrode. BUT; . 5 - area of the emitting surface of the electrode, determined by its geometry, m j. - ion current density With a positive voltage on the electrode, an apparent increase in the ion current by the amount of thermal emission from the surface of the metal 151-2Е (vm + 5) ZteZ , (7.) where Ig - current saturation with put. body voltage on the electrode, .A; 5 - area of metal emitting noBepi (determines with converter geometry). Sy, the area of the cold (non-emitting) surface electrically contacting with the emitting surface of the metal (determined by the converter's structure and the location of the electrode), j is the density of the thermal emission current, A / m. The density of the thermionic current is determined by the temperature of the metal and the electron work function j.oLoT O-,) where cLy is the Richardson thermoelectronic constant, A / (m / k) T is the temperature of the metal. TO; F is the work function of electrons. from the surface of the metal, B, Since the surface of the melt is a mixture of metal and slag, the value of H dl. Such a surface lies within 3.8-5.3 V, which for typical temperatures gives the value of the thermionic current. The change in H due to the variation of the chemical composition of the surface of the melt during purging is monitored by the change in the contact potential difference between the electrode and the bath, for example, by the Thomson-Zisman method. ., where a .. contact potential difference, V; electron work function from the surface of the electrode, B. Taking into account relations (1) .- (4) /, the temperature of the metal is found from the following expression: TO40 (hN9) (5) doT.O t -c-La-iUi ol -f m%). -a USw 2s ,, From the expression (5) it follows, 2e (VJoT) .e (LSz-oi.I ..). where Teg- () -5040 (), I -, (T) fg-Uilsa-o-il); Thus, the use of additionally inserted electrodes, mounted in a metal, a contact potential difference meter, a control unit, three memory blocks and the connections between them, allows the temperature of the metal in the converter to be controlled with higher accuracy, since this eliminates the component of errors caused by the ambiguous connection of the electrical conductivity of the flame with the temperature of the metal (except for the temperature of the metal, the electrical conductivity is influenced by the decarburization rate and the slagging mode). Figure 1 presents the block diagram of the device; figure 2 - the internal structure of the computing unit; FIG. 3 shows the internal structure of the control unit; FIG. Fig. 4 is a sequence diagram of the operation of contacts of a time relay (fg, is the duration of the time for calculating the temperature value); in FIG. 3, n & Measurement of metal temperature. . The device for controlling the temperature of the metal in the converter (Fig. 1) contains an electrode 1 installed in the core of the flame, an electrode 2 installed in the metal, a converter 3, a potential difference meter 4, a potential difference, a control unit 5, a meter 6 current, a power unit 7, a meter 8 oxygen flow rate, meter 9 distances of the tuyere nozzle to the level of calm metal, lance 10, oxygen flow sensor 11, sensor 12 of the distance of the nozzle of the tuyere to the level of calm metal, first memory block 13, second memory block 14, third block 15 memory computing unit 16 ,. metal temperature indicator 17. Electrode 1, made, for example, in the form of a water-cooled probe, is installed in the core of the torch, and electrode 2, made, for example, in the form of a meter. The pin is installed in the lining of the converter. 3 Below the metal level in the wear zone of the refractory brick. The electrodes 1 and 2 are connected to the meter 4 contact potential difference, the output of which is connected. with the control unit 5.. Electrode 1 is also connected via current meter 6, control unit 5 to power supply unit 7, which is also connected to electrode 2 through control unit 5. Current meter output 6 is connected to control unit 5, to which An oxygen consumption meter 8 is connected. The distances between the 9 nozzles of the tuyere 10 and the level of the calm metal are connected to the corresponding sensors 11 and 12. The output of the control block 5 is connected to the first 13, second 14 and third 15 memory blocks, which through computing unit 16 is connected to metal temperature indicators 17. The internal structure of the computing unit (Fig. 2) contains the first summing node 18, the first multiplication node 1, the second summing node 20, the second multiplying node 21, the first functional conversion node 22; a compensating conversion node 23, a division node 24, a second functional conversion node 25, a third summation node 26, a third multiplication node 27, a fourth multiplication node 28, a fourth summing node 29, a delay node 30, the output of the first summation block 18 of the computing unit through nep oh multiplication node 19 is connected to the input; the second summation node 20, which is furthermore connected through the second multiplication unit 21, the first functional transformation unit 22 to the compensating conversion unit 23. The output of the second summation node 20 is associated with the in-stroke of the division node 24, to which, besides, through the second functional transformation node 25 and the third summation node 26, the outputs of the third 27 are connected to the fourth 2.8 multiplication nodes. The output of the division node 24 is connected to the fourth 29 summing node and the compensating converter node 23, the output of which, in turn, is connected to the delay node 30; the fourth summing node 29 and directly to. the second node 21 multiplying. The nodes of the computational unit can be executed, for example, on the basis of the KTS LIUS-2 blocks. Internal, the structure of the control unit (fig. 3) contains node I 31, node NO 32, timer 33, time relay 34, first — eighth time relay contacts 1РВ - 8РВ / Input node AND 31 of control unit 5 is connected with node HE 32 The output of the node AND 31 is connected via timer 33 to the time relay 34. The inputs of the second 2РВ and the fourth 4РВ to-on contacts of the time relay are interconnected, and the inputs of the third ЗРРВ and the fifth 5РВ contacts are also interconnected. The outputs of the second 2РВ and The third ZRV contacts are interconnected, the outputs of the fourth 4РВ and fifth 5РВ contacts are also connected between The inputs of the sixth 6РВ and the seventh 7РВ contacts are interconnected. The device works as follows. When lowering the tuyere 10 into the converter. 3. and supplying oxygen to the voltage from the OT-sensors, 11 oxygen consumption and 12 distances of the tuyere to the level of the quiescent metal, the corresponding gauges 8 and 9 are transmitted. When these parameters reach a value of 75% of the nominal, the position contacts in the gauges B and 9 are triggered, including the control unit 5. The control unit 5 connects the output of the meter 4 of the contact potential difference, for example, an electronic potentiometer, to the first memory block 13, for example, a secondary device of the Kharkov instrumentation plant. The meter 4 measures the contact potential difference between the electrode 1 and the surface of the melt, due to the difference in the work output. Thus, the readings of the first memory block 13 will be proportional to the value 0 | Next, the control unit 5 disconnects the meter 4 from the memory unit 13 and connects the power supply unit 7 to the electrode 2 circuit - torch electrode 1 - current meter 6. The power supply unit 7 generates a sawtooth pulse voltage. When the voltage level approaches the maximum value, the 5-control unit connects the output of the meter. 6 current, for example, an ammeter, to the second memory block 14. This reading of memory block 14 is proportional to the value of ii. Next, control block 5 disconnects memory block 14 from current meter 6, switches the circuit polarity — and when level-voltage approaches the maximum control block 5, connects the current meter output 6 to the third swath of 15 memory. In this case, the readings of the memory block 15 are proportional to the value 15/2. . The control unit 5 sends a command to the computing unit 16 to perform calculations of the temperature value by the relation (7). The calculated value is transmitted to the metal temperature indicator 17, made in the form of an adder that converts the temperature value from absolute to Celsius. At the same time, from the computing unit 16 to the control unit 5 a signal about the end of measurements is received. By this signal, block 5 brings the device to the initial position and the measurement cycle repeats. At the end of the purge, the position contacts in the meters 8 and 9 open and the control unit 5 is switched off.

Computing unit 16 operates as follows.

A voltage proportional to the magnitude is supplied from the second memory block 14 to the third multiplication node 27,. where is the calculation of the value of (.2 15, and the voltage is about the pro-pore value). It comes from the third memory block 15 to the fourth multiplication node 28, where the calculation of the value is 1. 1. The output voltages of the nodes 27 and 28 come from to the third summation node 26, the output voltage of which is proportional to the value (of-tf g. C High voltage from the node 26 enters the second node 25 of the functional conversion, the output voltage of which is proportional to non-source E (oi,. 1 S-) enters the node-division of 24. The voltage is proportional to E, the value of UK, enters, with the first memory block 13 into the first summation node 18, in which the value Ne is entered as a task. Output voltage of the node

18, proportional to the value () enters the first multiplication node

19, in which a value of 5040 is computed (- to E Voltage proportional to an arbitrary metal temperature value, 23 compensating conversion arrives at the first functional conversion unit 22, the output voltage of which is proportional to 2 & (iQ). From the output of the node 22 the voltage goes to the second node 2G multiplying where the voltage from the output of the node 23 simultaneously arrives. Thus, the input of the second summation node 20 receives a voltage proportional to the value of STfo- (VdoT) / and is removed from the output The voltage proportional to the numerator of the expression (7). The voltage from the output of the node 20 enters the dividing unit 24, the output of which relieves the voltage proportional to the right side of the expression (7). The resulting voltage enters the compensating converter unit 23, where the new value of T is equal to the value in the right part of expression (7). The value of T found is the root of equation (7). At the same time, the voltage from nodes 24 and 23 goes to the fourth summation node 29, and the voltage from node 23 is preliminarily delayed in node 30 delays. When these voltages are equal, the voltage from the output of the node 29 is removed, which corresponds to a logical zero, which is fed to the control unit 5, as a signal that the calculation of the temperature has ended. The delay unit 30 avoids the supply of spurious signals to the control unit 5 in transients ... The control unit 5 operates as follows.

The voltages from the positional contacts of the meters 8 and 9, corresponding to the logical unit during the purge, enter node I. 31. The signal of the computing unit 16 inverted at the HE 32 node also signals the end of the calculation of the temperature value. The node 31 operates and switches on the timer 33, which starts the time relay 34. The first contact 1РВ time relay triggers, which connects the output of the meter 4 of the contact potential difference to the first memory block.13. Then the 1PB contact opens, the 2PB and 5PB contacts are activated, connecting the power supply unit 7 to the electrode circuit 2 - bath torch - electrode 1 - current meter After the time required to reach the current mode, the 6РВ contact switches on the second current output meter block 14 of memory. Then the 2РВ, 5РВ and БРВ contacts open, and

triggered volt contacts ZRV and 4РV, connecting the power supply unit electrode 2 bath - torch - electrode 1 - current meter b. After the time required for the current to reach saturation mode, the 7РВ contact is activated, connecting the output of current meter 6 to the third memory block 15. Then the contacts ЗРВ, 4РВ and 7РВ are opened and the contact 8РВ is activated, which turns on the computing unit 16 in the calculation mode. After the calculation is completed, node 31 is unlocked, including timer 33, and the temperature control cycle is repeated.

 Figure 5 shows an example of calculating the temperature of a metal T 1800 K with the following values of the parameters:, 8 V, 064 A

, 721 A, 4.1 V, o (3.8 "

 -0.167 m Numerical values of consecutive 4-fold iteration. K: 1600,000 - 1813,522 - 1799, 147 - 1800,054. Further calculations are impractical because the desired temperature value is between values that differ by less than 1 K 1799,996, 1800.00 - 1800,000 ...

The study shows that the standard deviation of the metal temperature from the actual compared with the base object decreases by 1 ,, which leads to a decrease in cost by 0.07 rubles / t of steel due to an increase in converter productivity by 1.5% due to a reduction in intermediate swings, an increase in lining durability by 2% and reject reduction by 0.1%.

Sm 5/1 from 5

Dmbfloxais

Dm 114 l 15

2f

Dtnij3 / ia 29 A ffenfi A K Dm measure /) 3

JJ 2PB 3Pb PB WB, U: 4V

/ 775

Sh

1500 500 1700 then W

5

Claims (3)

1. TEM- CONTROL DEVICE PERATURE ’METAL IN THE CONVERTER, containing an electrode, a current meter, a power supply, a computing unit connected to a temperature indicator. metal, characterized in that, in order to improve the accuracy of control, it additionally contains an electrode installed in the metal, a contact potential meter, a control unit, three memory blocks, and the inputs of the contact potential meter are connected to the electrodes installed respectively in the core torch and in metal, and the output with the input of the control unit, to which the outputs of the current meter and the power supply are also connected, in addition, the outputs of the control unit are connected to the computing unit and from -. measuring the contact potential difference directly and through a current meter, as well as through the first, second and third memory blocks, respectively, with a computing unit, which is connected to the input of the control unit. - 2. The device according to π. 1, the difference being that the computing unit contains four summation nodes, four multiplication nodes, two functional transformation nodes, division, delay and compensating conversion nodes, and the output of the first 'summation node through the first multiplication node is connected to the input of the second summing node, the input of which, in addition, is connected through the second multiplication node and the first functional transformation node to the compensating transform node, and the output of the second summing node is connected to the input of the division node, to to which, in addition, through the second node of the functional transformation. and the third node of the summation connected outputs of the third and fourth nodes of the multiplication, the outputs of the division node are connected to the four! the summing node and the compensating transformation node, in its own, ’Queue, one output of which through the delay node is connected to the fourth summation node, and the other output is directly connected to the second multiplication node. 3. The device according to p. Characterized in that the control unit contains an AND node, an HE node, a timer and a time relay with eight contacts, the input of a time relay through a timer and an AND node connected to the output of the NOT node, the inputs of the second and fourth contacts the time relays are interconnected, the inputs of the third and fifth contacts of the time relay are interconnected, the outputs of the second and third contacts of the time relay are interconnected / the outputs of the fourth and fifth contacts of the time relay are interconnected, the inputs of the sixth and seventh relay contacts. enes ° between them. <1 s © No. r ’>