JP2503301B2 - Blow-through prevention method in blast furnace operation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to blast furnace operation, and more particularly to prevention of blow-through in a blast furnace.

[Conventional technology]

When the pressure loss in the furnace locally increases during blast furnace operation and it becomes in a state of being balanced with the load of the charge, local stoppage of the charge, so-called hanging, occurs. Stops and creates a cavity under the hanging as the furnace interior contents fall below the hanging. When this cavity becomes large to some extent, the charge on the outside of the hanging system slips into the cavity, which causes the local hanging process to collapse. If the shelving is large and the collapse occurs suddenly, a large amount of the charged material moves locally and relatively quickly, causing the pressure loss inside the furnace to decrease locally and blowing up the gas inside the furnace upward. , At this time, the charge is blown up to the top of the furnace. This kind of blow-up is called so-called blow-through, and the temperature distribution in the furnace,
The distribution of the charge may be disturbed to prevent normal heat exchange and ringing, disturbing the hot metal temperature, etc., or, in severe cases, cooling. Moreover, since the temperature at the top of the furnace rises extremely,
It is also a major problem in maintaining blast furnace equipment.

Japanese Examined Patent Publication No. 1-20203 discloses that the static pressure of the inner surface of the furnace wall at a plurality of positions in the height direction of the blast furnace is measured, and from these static pressures,
Obtain the pressure loss from each measurement position to the furnace top, meanwhile, determine the charge load from each measurement position to the furnace top, and blow into the furnace according to the calculated ratio of pressure loss and charge load. Techniques have been proposed to adjust the blowing conditions to prevent the above-mentioned hanging (and the slip and blow-through caused thereby).

[Problems to be Solved by the Invention]

However, the load on the interior of the blast furnace depends on the properties of the sinter (grain size, TFe, reduced pulverization property, strength, etc.), coke properties (grain size, reduced pulverization property, strength, etc.), and furnace conditions (blast furnace wall Wear: Changes in internal volume, changes in frictional resistance), and the accuracy of calculating (estimating) the load of the charge at each point in the furnace is low, and therefore the accuracy of estimating the possibility of rack hanging is low. As a result, in order to increase the reliability of restraint such as hanging from a shelf, the amount of air blow is excessively restrained and the stability of operation is disturbed. Loosening the control of the air flow increases the possibility of hanging on a shelf. Therefore, a more reliable blow-through prevention technique is desired.

It is an object of the present invention to increase the reliability of detection of the possibility of occurrence of blow-through and further improve the stability of blast furnace operation.

[Means for solving the problem]

In the first invention of the present application, it is determined for a predetermined time whether each of the in-reactor pressures (Pij) at a plurality of points at different positions in the furnace wall height direction below the stock line in the blast furnace shaft portion is equal to or higher than a reference value (Pis). Time interval Tps less than Td (20sec) Tps (10se
detected in c), and within a predetermined time Td (20 sec) after the reactor pressure (Pij, i = middle stage or lower stage) of any of the points other than the uppermost position becomes equal to or higher than the reference value (Pis). When the pressure in the furnace at the uppermost position (Pij, i = upper stage) exceeds the reference value (Pis), the amount of air blown into the blast furnace is reduced (Fig. 2b, 13 to 1).
6).

In the second invention of the present application, the furnace pressure (Pi in the upper stage in the furnace wall height direction below the stock line in the blast furnace shaft portion)
It is detected at a predetermined time interval Tpsa (10 sec) whether j, i = upper) is greater than or equal to the reference value (Pis); the difference (ΔH) between the upper surface levels (Lj) of the blast furnace interior entrance at multiple points in the furnace circumferential direction. ) Is the reference value (Δ
Hs) or more is detected at a predetermined time interval Ths (10 sec), and whether or not the load descending speed (dLj) at each position of the upper surface level (Lj) is the reference value (dLs) or more is timed.
Detected at Tfs (10 sec); the upper furnace pressure (Pij, i = upper) is a reference value (Pis) or more, and the upper surface level difference (ΔH) is a reference value (ΔHs) or more (DΔH = 1) and the lowering speed (dLj) of each of the upper surface level (Lj) is at least one of the reference values (dLs) or more (DdL = 1), the air flow rate into the blast furnace is reduced ( 34c in Fig. 2c
37).

In the third invention of the present application, the in-furnace pressure (Pij, i = upper stage) in the upper stage in the furnace wall height direction below the stock line in the shaft portion of the blast furnace is detected at a predetermined time interval Tpsa (10 sec); The change amount (dTej) of the furnace top gas temperature (Tej) of a plurality of rising pipes of
c); the gas temperatures (T _sj ) at multiple points in the circumferential direction of the blast furnace just below the surface of the charge on the upper part of the blast furnace shaft are determined at predetermined time intervals T _its.
Detected within (2 sec); the upper furnace pressure (Pij, i = upper) is above the reference value (Pis) (DMd = 1) and the furnace top gas temperature (Tej) of the plurality of risers At least one of the change gradients is equal to or higher than the reference value Vp (dTmax ≧ Vp) and at least one other is equal to or less than the reference value Vn (dTmin ≦ Vn), and at least one of the furnace top gases has a blow-through prediction reference value (dTe ) When the above temperature drop is shown (DRd = 1 & DdT = 1), or in the furnace gas temperature (Tsj) at any of several points in the circumferential direction of the blast furnace just below the surface of the charge above the blast furnace shaft. Of the temperature change (ΔTs) within a predetermined time Ts ( ₁₀ sec) within a reference value (ΔTs _{1 to} ΔTs ₂ ) range, at least one of the plurality of in-furnace gas temperatures (Tsj) indicates a reference value or more, or , At least one of the gradients of the top gas temperature (Tej) of the plurality of risers (Tsma
When x) is greater than the reference value (Tss) (DT = 1), the amount of air blown into the blast furnace is reduced (69-70-37 in Fig. 3c).

The symbols in parentheses indicate the symbols attached to the corresponding items of the embodiments of the present invention described below.

[Action]

When the in-furnace pressure of the blast furnace shaft is measured at multiple points in the height direction, time-series pressure fluctuations appear, for example, as shown in FIG. A certain time (for example, 20
sec, this time varies depending on the interval between shaft pressure measurement points, and this value is when the pressure measurement interval is 1 m. There is a high possibility that blow-through will occur when the shaft pressures in the middle and upper stages gradually increase above a predetermined pressure (allowable blow-through limit value).

This is because when the charge around it begins to collapse into the cavity created in the charge, a relatively large amount of in-furnace gas flowing in the cavity is blocked and the other flow is blocked. Attempting to flow, the pressure in other parts rises at this time, and the gas in the furnace flows from the lower part of the shaft to the upper part, and it is speculated that this pressure increase is sequentially propagated from the lower part of the shaft to the upper part.

Therefore, as in the first aspect of the invention described above, are each of the in-reactor pressures (Pij) at a plurality of points at different positions in the furnace wall height direction below the stock line in the blast furnace shaft part equal to or greater than the reference value (Pis)? Is detected at a time interval Tps (10 sec) of a predetermined time Td (20 sec) or less, and a predetermined time Td (20 sec) after the pressure in any one of the plurality of points other than the uppermost position becomes a reference value or more. It can be judged that there is a possibility of blow-through when the pressure in the furnace at the highest position becomes higher than the reference value. By the way, when the position where the shaft pressure rises is the lower stage of the shaft, the gas flow may be dispersed or slowed down due to the influence of a large amount of the charge accumulated on the upper part of the shaft to prevent blow-through. If the pressure rise position is at the upper stage of the shaft, it is highly possible that a large amount of the in-furnace gas that has risen with little influence of the charge flows out from the surface of the charge and blows through.

Therefore, in the first invention, the furnace pressure (Pi
Within the predetermined time Td (20 sec) after the in-furnace pressure (Pij, i = middle or lower) at any position other than j, i = upper) exceeds the reference value (Pis), the highest in-furnace pressure Is the reference value (Pi
s) When it is above, there is a high possibility of a void, so
Reduce the amount of air blown into the blast furnace (16-18 in Fig. 2b).

As a result, the amount of air blown to prevent blow-through is reduced only when the possibility of blow-through is high, and the reliability of blow-through prevention is high, and the air flow rate is not sensitively (frequently) controlled and operation is stable. The property is improved.

Before the occurrence of the blow through, abnormalities occur in the unloading state such as hanging from a shelf, and local cavities occur in the charge. In such a state, the difference in the descending speed of the stock line level (the upper surface of the charge) in the circumferential direction of the blast furnace becomes large, and the difference in the height of the stock line level becomes large.

In the second aspect of the invention, it is determined whether the upper furnace pressure (Pij, i = upper) is equal to or higher than the reference value (Pis) at a predetermined time interval Tpsa.
(10 seconds) to detect.

Further, it is detected at a predetermined time interval Ths (10 sec) whether the difference (ΔH) between the upper surface levels (Lj) of the interior contents of the blast furnace at a plurality of points in the furnace circumferential direction is equal to or greater than a reference value (ΔHs), and the blast furnace Whether the descent rate (dLj) at each position on the inner surface of the inner container is equal to or higher than the reference value (dLs) is detected at a predetermined time interval Tfs (10sec), and the upper furnace pressure (Pij, i = upper) is detected. Reference value (Pis)
Above, the difference (ΔH) in the upper surface level (Lj) is the reference value (ΔHs) or more, and the descent rate (dLj) at each position of the upper surface level (lj) at multiple points in the furnace circumferential direction is at least one. Reduces the amount of air blown into the blast furnace when a person satisfies the standard value (dLs) or more (34 to 37 in Fig. 2c). That is, the furnace pressure (Pij, i = upper stage) in the upper stage of the shaft is the reference value (Pis)
Above, when the height difference of the upper surface level of the charge is large and the descending speed of the upper surface level of the charge is high, the air flow rate is reduced.

According to the second aspect of the invention, the reliability of blow-through prediction is further enhanced, and the stability of operation is further improved.

By the way, if a cavity with a large size is generated in the charging material, the temperature distribution of the furnace top gas in the circumferential direction of the blast furnace is disturbed, and the temperature of the furnace top gas at a certain position in the circumferential direction of the blast furnace tends to decrease. When the furnace top gas temperature tends to rise, the deviation of the furnace top gas temperature in the circumferential direction becomes large, and when the hanging of the shelf collapses, the furnace top gas temperature at the position where it has tended to rise greatly decreases. That is, when the charge begins to collapse into the cavity, the gas flow in the furnace flowing through the cavity decreases and flows out from the surface of the charge in the vicinity of that part and flows into the furnace top rising pipe above that part. The temperature inside the furnace begins to decrease from a relatively high temperature, and the gas flow inside the furnace flowing at other positions increases and flows out from the surface of the charging material at that portion and rises above the surface. Flowing into the furnace, the temperature of the gas in the furnace rises, and when it reaches the blow-through, the temperature of the gas in the furnace at the position that had been rising tends to rise more rapidly.

In the third invention, paying attention to this phenomenon, it is detected at a predetermined time interval Tpsa (10 sec) whether the upper furnace pressure (Pij, i = upper) is equal to or higher than a reference value (Pis), and the blast furnace The decrease amount (dTej) of each of the furnace top gas temperatures (Tej) of the plurality of rising pipes at the top is detected at a predetermined time interval Tets (10 sec), and the temperature gradient of the furnace top gas temperature for each rising pipe Zj is further detected. It is calculated at a predetermined time interval Tda (60 seconds). Then, the furnace pressure (Pij, i = upper stage) at the uppermost position of the shaft is equal to or higher than the reference value (Pis) (DMd = 1), and the predetermined time Tda of the plurality of riser pipes
At least one of the temperature gradient of the furnace top gas temperature (Tej) within (60 sec) is the reference value Vp (7 ° C / min) or more (dTmax ≧ Vp) and the other at least one is the reference value Vn (3 ° C). / Min) or less (dTmi
n ≦ Vn) and at least one of the furnace top gas temperatures shows a temperature drop more than the blow-through prediction reference value (dTe) (DRd = 1
& DdT = 1), reduce the amount of air blown into the blast furnace (69-70-37 in Fig. 3c). That is, the pressure in the upper furnace (Pij, i ＝
(Upper) is above the reference value (Pis) (DMd = 1), and the temperature gradient of the top gas at one position in the circumferential direction of the blast furnace is lower than the reference value, and the temperature gradient of the top gas at other positions is below the reference value. Rise,
Further, when the lowered furnace top gas temperature shows a temperature drop fluctuation of a reference value or more, the air flow rate is reduced.

According to the third aspect of the present invention, since the blow-through prediction is performed with the detection of the variation in the distribution of the furnace top gas temperature in the circumferential direction, the reliability is further increased and the stability of the operation is further improved.

Also in the fourth invention, paying attention to the above-mentioned phenomenon, it is detected at a predetermined time interval Tpsa (10 sec) whether the upper furnace pressure (Pij, i = upper) is equal to or higher than the reference value (Pis), and the blast furnace Gas temperature (Ts) at multiple points in the blast furnace circumference in the charge above the shaft
Detect each of i). The upper furnace pressure (Pij, i = upper) is equal to or higher than the reference value (Pis) (DMd = 1) and the furnace gas temperature (Tsj) at any of multiple points in the blast furnace circumferential direction
The temperature change (ΔTs) within a predetermined time Ts ( ₁₀ sec) of is within a reference value (ΔTs _{1 to} ΔTs ₂ ) range, and at least one of the plurality of points (Tsmax) becomes equal to or greater than the reference value (Tss) (DTs). = 1)
Sometimes it reduces the air flow (69-70-71-37 in Figure 3c).

Also in the fourth aspect of the invention, since the blow-through prediction is performed by also detecting the skin flow gas temperature change detection, the reliability is further increased and the operation stability is further improved.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

[First and Second Embodiments of the Invention] FIG. 1 shows an outline of an apparatus for carrying out the present invention. In this example, the stock line in the shaft part of the blast furnace
Four pressure gauges P ₁ j to P ₃ j (12 in total) are installed at equal intervals in the blast furnace circumferential direction at each of the lower, middle, and upper stages below the ST, each at each position. Furnace pressure of Pij
Is detected and the pressure detection signal is input / output interface (ON,
Output signal processing circuit) Give to SPC. In normal operation,
Four thermometers (skin flow gas thermometers) Tkj that detect the temperature of the gas in the furnace 1 m below (immediately below) the upper surface level of the minimum charge (skin flow gas thermometer) are arranged at equal intervals in the circumferential direction of the blast furnace. It is installed and gives a temperature detection signal indicating the furnace gas temperature Tsj (skin flow gas temperature) rising in the charge to the input / output interface SPC. A sounding device Sj is installed above the shaft, which detects the level (height) Lj of the upper surface of the charge at four points that are set at equal intervals in the circumferential direction, and outputs the level signal as an input / output interface. Give to SPC. There are four rising pipes Zj on the top of the blast furnace, which are also equipped with gas thermometers Tzj, which measure the gas temperature Tej rising in the rising pipe Zj and give a signal indicating the furnace top gas temperature. I / O interface SPC is given.

Numbers 1 to 4 are given to the rising pipe Zj, and j of the gas temperature Tej of the rising pipe Zj indicates the rising pipe No. number (j = 1 to 4), that is, the gas temperature Tej of the rising pipe Zj. Is the gas temperature in the riser pipe of No. j, the furnace pressure Pij measurement position at each stage of the shaft (i = 1 is the upper stage, 2 is the middle stage, 3 is the lower stage; circumferential direction j = 1 ~ 4), skin flow gas temperature Ts
j measuring device (circumferential direction j = 1 to 4), each of the charge upper surface level Lj measuring positions (circumferential direction j = 1 to 4) (circumferential direction j) is the vertical axis of the blast furnace. And on each vertical plane including the center axis of each riser Zj.

That is, if the furnace gas rises symmetrically with respect to the blast furnace axis, Pij is the pressure of the furnace gas that rises in the shaft portion toward the rising pipe No.j, and Tsj rises just below the upper surface of the charge. Skin flow gas temperature rising toward tube No.j, Lj is the level of the charge surface closest to the rising tube No.j, Te
j is the temperature of the gas at the top of the furnace rising in the rising pipe No. j.

The sounding device Sj continuously measures the charge levels at four points in the circumferential direction, continuously inputs the same to the input / output interface SPC, and latches the measured data therein at a cycle of 10 seconds. The shaft pressure gauges P ₁ j to P ₃ j each continuously input the pressure detection data to the input / output interface SPC and latch it there at a cycle of 2 seconds. Skin flow gas temperature Tsj
The skin flow thermometer Tkj for measuring the temperature and the furnace top thermometer Tzj for measuring the gas temperature Tej in the rising pipe continuously input the temperature detection data to the input / output interface SPC and latch the data at a cycle of 2 seconds.

The input / output interface SPC edits and holds all the latest measurement data given in a set of data frames at a cycle of 2 seconds. When the computer CMR requests data, the set of data is set. Transfer the frame to the computer CMR.

The computer CMR requests measurement data from the input / output interface SPC at a cycle of 2 seconds, receives a set of data frames, extracts the required data from the data frames, and executes the blowout prediction process described later to generate blowouts. The possibility is determined, the ventilation control data corresponding to the determination result is created, and when the measurement data is requested, the ventilation control data is output to the input / output interface SPC together with the transfer instruction signal.
The input / output interface SPC sends the air blow control data from the computer CMR to the air blower BRA.

2a to 2c show the contents of the blow-through prediction process of the computer CMR.

First, referring to FIG. 2a, when starting this process, the computer CMR first starts a 2-second timer and waits for 2 seconds (steps 1 and 2; in the following, the word step is omitted in parentheses and only a number is given). Note). When 2 seconds have passed, the 2-second timer is restarted (3) and the measurement data is read from the input / output interface SPC (4).

For the shaft pressure Pij (12 in total), the value read this time and the value read four times in the past are stored in the permanent register for a total of five values, and the highest value Pijmax among them is calculated to obtain the latest value. The maximum value Pijmax is held in the register (5). And every 10 seconds (every 5 times data reading) (6 to 7),
It is checked whether the maximum value Pijmax is greater than or equal to the reference value pis (9), and when it is greater than or equal to the reference value Pis, the data "1" indicating this is written in the register DPij (10). If it is less than the reference value Pis, the register DPij is determined. Clear (11). As for the reference value Pis, those for the upper shaft (i = 1) are divided to P ₁ s for 3.4 kg / cm ² , and those for the middle shaft (i = 2) for P ₂ s are 3.7 kg / cm ² . cm ^2, P ₃ s which are addressed assigned to the shaft lower (i = 3) is 4.0 Kg / cm ^2. Register DP
The table (memory area) in which the data of ij is written has the storage area distribution of the MPM shown in FIG.
One row (3 areas 0 to 2) is assigned to Pij. Write the judgment data this time to the register DPij (10,1
1), the computer CMR writes the judgment data of column No. 1 of MPM to column No. 2, the judgment data of column No. 0 to column No. 1, and the judgment data of this time (the contents of DPij ) To column No. 0
Write on (12). As a result, the MRM always has the past 20 seconds
During this period, the data judged every 10 seconds will be written.

Reference is now made to FIG. 2b. The computer CMR determines that the pressure Pij (i = 1) in the upper shaft is equal to or higher than the reference value, that is, when the register DPij (i = 1) becomes 1, the pressure Pij (i = 2 or 3) in the middle or lower shaft within the past 20 seconds. Was above the standard value (there is a high possibility that a blow-through will occur within a short time: urgent action is required). In other words, check whether there is 1 in the lower column No. 0 to 2 in the table MPM. Then (13,1
4) If so, generate the air volume reduction instruction data for coping with the blow-by and give this to the blower device BRA via the input / output interface SPC (15), and display the CRT display DIS on the current measurement data. , Update the judgment data, the air flow rate data of the air blower, and the cautions for blown air (16).

When it is determined that an urgent countermeasure is required as described above, the blow-through limit index F, RIV: Effective internal volume of blast furnace, OC: ORE / COKE (-), ρc: COKE bulk density (t / m ³ ), ρ ₀ : ORE bulk density (t / m ³ ), BV: Air flow rate (Nm ³ / min), TP: Furnace top pressure (Kg / cm ² ), S: Furnace mean cross-sectional area (m ² ) given the value for emergency prevention of blow through, and calculated by back calculation
BV is calculated, and the value for increasing the safety level is subtracted from the calculated air flow rate BV, and the air flow rate data indicating the remaining value is sent to the air blower.
Give to BRA (15).

When it is not judged that an urgent action is required, the air flow rate calculation value for normal operation determined at that time is given to the air blower BRA (17), and the display of the CRT display DIS displays the current measurement data, judgment data and air flow. The air flow rate data of the device and the absence of blow-through are displayed (18).

The above is the blow-through (occurrence within a short time) prediction and blow-through emergency prediction processing based on the detected pressure value of the shaft portion.

Next, the contents of the blow-through prediction and blow-through prevention processing in the embodiment of the second aspect of the present invention, which has a little more time, will be described.

The computer CMR reads the latest surface level measurement value Li every 10 seconds, and subtracts the value Li from the surface level measurement value 10 seconds before (the last read value) to obtain the past 10se.
Calculate the surface level drop dLj between c (21 to 25). Then, it is checked whether the descent amount dLj is greater than or equal to the reference value dLs (1.0 m) (26), and if it is, the determination data register DdL
Write "1" to (27A), and if not, clear the judgment data register DdL (27B). Next, the maximum value Lmax and the minimum value Lmin of the surface level measurement values Lj, j = 1 to 4 are extracted (28, 29).

Now referring to FIG. 2c. Next, the computer CMR calculates the deviation ΔH between the maximum value Lmax and the minimum value Lmin (30), checks whether the deviation ΔH is equal to or greater than the reference value ΔHs (0.5m) (31), and determines that it is. "1" is written in the data register DΔH (32), and otherwise, the judgment data register DΔH is cleared (33). The computer CMR then stores a table MPM that stores data indicating whether or not the shaft pressure value is higher than the reference value (“1”) (“0”).
The data in column No. 0, i = 1 (upper row) of (Fig. 2a) is read, and it is checked whether the data is "1" (34).
That is, each position in the circumferential direction of the upper part of the shaft (j = 1 to 1
It is checked whether any of the gas pressures in 4) is currently abnormally high (abnormal increase in gas pressure in the upper stage of the shaft). Furthermore, whether the registers DdL and DΔH are “1”,
That is, it is checked whether or not the descent speed of the surface level of the charged material is equal to or higher than the reference value (abnormal descent) (35) and whether the surface level deviation is abnormally high (36). And all are "1". In other words, if the gas pressure in the upper part of the shaft is abnormally high, there is a current descent abnormality, and the level deviation is abnormally high, it is possible that blow-through will occur in the near future, and air volume reduction instruction data for blow-through prevention measures will be generated. Then, this is sent to the blower device BRA via the input / output interface SPC.
(37) and update the display on the CRT display DIS to show the current measurement data, judgment data, air flow rate data of the air blower and blowout caution (3
8).

When determining the possibility of blow-by as described above, the blow-through prevention blow air amount is calculated and given to the blower BRA as in the case of the emergency measure described above.
The amount of wind reduction in this case is small. In other words, since there is a little time margin compared to the case where emergency measures are required, the situation will be seen with a small amount of wind reduction. It should be noted that the above-mentioned blow-through prediction based on the gas pressure in the upper part of the shaft and the surface level of the charge is 10
It is executed every sec, and when the possibility of blow-by is subsequently detected, the air reduction amount is gradually increased.

When the possibility of blow-by is not determined, that is, when one of the registers of the three parties is “0”, the blower amount BRA is given to the blower device BRA with the blown air amount calculation value that is determined at that time (39). ), The CRT display DIS display shows the current measurement data, judgment data, air flow rate data of the air blower and no blow-through (4
0).

[Embodiment of No. 3 and No. 4 Invention] FIG. 3a shows the processing operation of the computer CMR of this embodiment.
Shown in Figure 3c. In this embodiment, 1 to 12 in FIG. 3a are the same as those in the previous embodiment, and the description thereof is omitted here. 10 sec
The computer CMR reads the skin flow gas temperature from the input / output interface SPC at intervals of 2 seconds each time (41). This read skin flow gas temperature Tsj, j ＝
For every 1 to 4, the maximum value Tsmax and the minimum value Tsmin are extracted from the read skin flow gas temperatures of this time and the previous time (5A). Then, the extracted skin flow gas temperature Tsj, j = 1 to 1
The difference between the maximum value Tsmax and the minimum value Tsmin for each 4, that is, the temperature change ΔT between 10 seconds at multiple points in the blast furnace circumferential direction
sj is calculated (51), and the temperature change amount ΔTsj is the reference value ΔTss (10
Temperature range (~ 20 ° C) (whether a large temperature change occurs in the skin flow gas temperature Tsj in the circumferential direction) (52), and if there is, then the above Tsjmax becomes the reference value Tss (3
It is checked whether the temperature is 00 ° C or higher (53), if there is any, write "1" in the judgment register DT (54), and if there is no any, clear the judgment register DT (55).

Also, every time 10 seconds elapse, the top gas temperature Tcj of the riser Zi is read and
The decrease amount dTej of each furnace top gas temperature during 0 seconds was calculated, and the furnace top gas temperature data read this time was changed from this time to 6
Write to the row register MTRj together with the calculation data up to the previous time (56, 57), and the temperature drop fluctuation amount dTej calculated this time is the reference value d
Check whether it is Te (20 ℃) or higher (whether there is an abnormal decrease fluctuation) (58). Judgment register when there is abnormal change
Write "1" to DdT (59) and clear the judgment register DdT (60).

Furthermore, every 10 seconds, the column of the table MPM (Fig. 3b) that stores data indicating whether the shaft pressure value is higher than the reference value ("1") ("0") is stored. No.0,
The data of i = 1 (upper row) is read and it is checked whether there is a "1" in them (34). That is, it is checked whether the gas pressure at any of the circumferential positions (j = 1 to 4) of the upper shaft portion is abnormally high at present (abnormal increase in gas pressure of the upper shaft portion). If there is an abnormal rise, "1" is written in the judgment register DMd (61), and if there is not, the judgment register DMd is cleared (62). In addition, from the data of the row register MTRj (Fig. 3b) (upper pipe top gas temperature dTej calculated every 10 sec during 60 sec), the top gas temperature gradient was calculated by the regression equation (63a, 63, 64), the maximum value d
Check if Tjmax is greater than or equal to the reference value Vp (7 ° C / min) and if the minimum value dTjmin is less than or equal to the reference value Vn (3 ° C / min) (65,66). At some time (one riser has a steep rise in gas temperature and the other riser has a gradual rise in gas temperature.
If it has decreased, "1" is written to the judgment register DRd (67), and if there is no one, the judgment register DRd is cleared (68).

The computer CMR further determines the contents of the judgment register DMd (whether or not the gas pressure in the upper stage of the shaft has abnormally increased) and the contents of the judgment register DRd (1 of the rising pipe) every 10 seconds.
Whether one furnace top gas temperature rises sharply and the other gas temperature rise is gentle or decreases), the contents of the judgment register DdT (abnormal fluctuation in the furnace top gas temperature of the rising pipe) Whether or not), and the contents of the judgment register DT (whether or not the skin flow gas temperature has a sudden temperature drop change at any position in the circumferential direction) (69
~ 71) When all are "1", that is, the gas pressure in the upper stage of the shaft abnormally rises, and the temperature of one gas in the riser pipe also abnormally rises, and the temperature of the other gas gradually rises. Or, in addition to the decrease, there is an abnormal decrease fluctuation in the furnace top gas temperature of at least one riser pipe, or the gas pressure in the upper stage part of the shaft increases abnormally, and the skin flow gas temperature increases in the circumferential direction. If there is a sudden temperature change at any of the positions, it is possible that blow-through may occur in the near future, and air-flow reduction instruction data for blow-through prevention measures is generated and this is sent via the input / output interface SPC. To blower device BRA (37) and CRT display
The DIS display is updated with the current measurement data, judgment data, air flow rate data of the air blower, and warning of blow-through tendency (38).

When the possibility of blow-through is determined as described above, the blow-through prevention blow amount is calculated and given to the blower BRA, as in the case of the emergency measure described above.

When the possibility of blow-by is not determined, the air flow rate calculation value for normal operation determined at that time is given to the air blower BRA (39), and the display of the CRT display DIS displays the current measurement data, determination data and The blower volume data of the blower and the absence of blow-through are displayed (40).

〔The invention's effect〕

According to the first aspect of the present invention, the amount of air blown to prevent blow-through is reduced only when the possibility of blow-through is high, and the reliability of blow-through prevention is high and the amount of blown air is suppressed with high sensitivity (high frequency). The stability of operation is improved.

According to the second aspect of the invention, the reliability of blow-through prediction is further high, and the stability of operation is further improved.

According to the third aspect of the invention, since the blow-through prediction is performed by additionally detecting the variation in the distribution of the furnace top gas temperature in the circumferential direction, the reliability is further increased and the stability of the operation is further improved.

According to the fourth aspect of the invention, since the blow-through prediction is performed by additionally detecting the skin flow gas temperature variation, the reliability thereof is further increased and the stability of the operation is further improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing an outline of an apparatus for carrying out the invention of the present application. 2a, 2b and 2c show the first embodiment of the present application,
3 is a flowchart showing the processing operation of the computer CMR shown in FIG. 1. 3a, 3b and 3c show a second embodiment of the present application,
It is a flow chart which shows processing operation of computer CMR. FIG. 4 is a graph showing changes in the in-furnace gas pressure in the vertical direction of the shaft portion of the blast furnace when blow-through occurs.

Claims (3)

(57) [Claims] 1. At a predetermined time interval Tps, it is detected whether or not the in-furnace pressure at a plurality of points at different positions in the furnace wall height direction below the stock line in the blast furnace shaft portion is at or above a reference value, and these plural points are detected. When the pressure in the furnace at the uppermost position becomes higher than the reference value within a predetermined time Td (Td> Tps) after the pressure in the furnace other than the highest position becomes higher than the reference value, A blow-through prevention method in blast furnace operation that reduces the amount of air blown. 2. The furnace pressure in the upper stage in the height direction of the furnace wall below the stock line in the shaft portion of the blast furnace is controlled at a predetermined time interval Tpsa.
It is detected at a predetermined time interval Ths whether the difference in the upper surface level at multiple points in the furnace circumferential direction in the blast furnace interior is more than the reference value, and the descent rate of each upper surface level is more than the reference value. It is detected at a predetermined time interval Tfs whether or not the upper furnace pressure is at or above a reference value, and the upper surface level difference at multiple points in the furnace circumferential direction is at or above the reference value and at least the descending speed of each of the upper surface levels. A method for preventing blow-through in blast furnace operation, in which the amount of air blown into the blast furnace is reduced when one person meets or exceeds a reference value. 3. The furnace pressure in the upper stage in the height direction of the furnace wall below the stock line in the shaft portion of the blast furnace is controlled at a predetermined time interval Tpsa.
The temperature changes in the furnace top gas temperature of the multiple risers at the top of the blast furnace and their gradients are detected at a predetermined time interval Tets. Each of the gas temperatures at a plurality of points is detected at a predetermined time interval T _its , the furnace pressure in the upper stage is equal to or higher than a reference value, and at least one of the gradients of the gas temperature (Tej) at the top of the riser pipes Is above the reference value and at least one other is below the reference value, and at least one of the furnace top gases shows a temperature drop above the blow-through prediction reference value, or the charge on the upper part of the blast furnace shaft. The temperature change in the furnace gas temperature (Tsj) at any of multiple points in the circumferential direction of the blast furnace immediately below the surface is within the reference value range, and at least one of the plurality of furnace gas temperatures is the reference or more. Or of the plurality of risers When at least one party of the change gradient of the top gas temperature indicates a higher reference value, it reduces the air volume into the blast furnace, blow prevention method in blast furnace operation.