JPS582601B2 - Display device for pressure fluctuation pattern in blast furnace - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention measures the pressure inside the blast furnace at the tuyere and shaft, and determines the fluctuation pattern of this pressure.
This technology relates to a device that digitizes and displays pressure fluctuation patterns in blast furnace operating methods that estimate the conditions inside the furnace and take control measures to maintain stable operation.

In a blast furnace, ore, coke, solvent, etc. (hereinafter referred to as charges) are charged from the top of the furnace, and reducing gas is generated by blowing high-temperature hot air from the tuyere to burn the coke. This reducing gas (hereinafter referred to as furnace gas) is used to reduce the ore and sequentially melt it.

Therefore, it is important to operate the furnace so that the gas in the furnace and the charge are in sufficient contact with each other and the charge smoothly descends inside the furnace.

However, in reality, abnormal phenomena (hereinafter referred to as "abnormal phenomena") occur in the furnace, such as hanging on shelves, slipping, uneven wear, and wall falls, making the descent of the charge unstable, and causing the gas in the furnace to drift. In many cases, blast furnaces cannot maintain smooth operation due to blow-through.

This is due to the properties of the charge, such as changes in particle size and decrease in strength, and the distribution of the blending ratio of ore and coke in the charge in the diameter direction of the blast furnace (hereinafter referred to as ore/coke distribution). Although the balance between the amount of gas in the furnace and the amount of gas in the furnace at that time may be disrupted, abnormal phenomena in the furnace often occur due to the latter cause.

For this reason, a movable repulsion plate or a rotating chute-type charging device is attached to the top of each blast furnace, so that the position of the repulsion plate can be changed or the angle of the rotating chute can be adjusted when charging the charge into the furnace. By changing the deposition form of the charge in the furnace, the ore/coke distribution in the diametrical direction can be changed in accordance with the gas flow distribution at that time, and the top charge can be changed in response to the occurrence of abnormal phenomena in the furnace. Measures are being taken to control the distribution.

Therefore, in order to perform these controls reliably, it is extremely important to predict changes in the gas flow distribution in the blast furnace and the occurrence of abnormal phenomena in advance, and to detect the location of occurrence and accurately grasp the situation inside the furnace. This is an important point.

As a means of estimating the situation inside the furnace, which predicts or detects changes in the gas flow inside the furnace or abnormal phenomena, it is possible to measure the top gas temperature distribution and shaft temperature distribution, or make inferences based on changes in the blowing pressure and blowing flow rate. There are several methods, including a method of inferring from changes in the fluctuating pattern of the lining pressure and shaft pressure.

The present invention is for quantifying the patterns when inferring changes in the furnace internal conditions from the latter fluctuation patterns of tuyere pressure and shaft pressure.

One way to infer changes in the conditions inside the furnace from changes in the wall pressure and shaft pressure is to pattern pressure changes.

An example of this is shown in FIG.

In other words, changes in the absolute value of each pressure occur in various patterns depending on the situation inside the furnace, but the magnitude of the rate of pressure change, that is, the ratio of the pressure change amount Δp and the change time Δt, Δp/
When measured as Δt (=differential value of pressure fluctuation) and squared to convert it into a so-called pressure change power signal, the first
As shown in the figure, it is classified into three patterns: A, B, and C.

Generally, when the power signal shows a change in pattern A,
If the descent of the person inside the furnace is unstable, and this phenomenon occurs frequently, it will lead to abnormal phenomena inside the furnace such as hanging on a shelf or slipping.

When pattern B is shown, there are many small cavities inside the furnace interior and the gas flow is fluctuating, and abnormal phenomena such as uneven loading of the charge are likely to occur.

It is also known that when pattern C is shown, the gas flow in the furnace is significantly localized, and if it continues for a long time, it will lead to abnormalities in the furnace such as blow-through.

In this way, the situation inside the reactor can be grasped from the wind pressure fluctuation situation, and abnormal phenomena can also be predicted.

Therefore, if wind pressure fluctuation patterns can be measured quantitatively and reliably, it is possible to respond to abnormal phenomena in the furnace situation estimated from the fluctuating patterns by, for example, changing the amount of air blown from the siding, or changing the distribution of the charge at the top of the furnace. By changing the shape, it is possible to prevent the occurrence and expansion of abnormal phenomena and maintain stable blast furnace operation.

However, conventionally, the reactor operator has interpreted the fluctuation pattern each time from analog signals of the absolute values of the wall pressure and shaft pressure, and estimated the situation inside the reactor.

Therefore, there are individual differences in the standards for pattern interpretation in terms of the strength, size, frequency, etc. of fluctuating patterns, making it difficult to quantitatively grasp the situation inside the furnace. It was becoming a problem.

The present invention solves these problems and is an apparatus that digitizes and displays pressure fluctuation patterns so that blast furnace operations can be quantitatively controlled.

The feature of the pattern display device of the present invention is that the change pattern of the square value of the rate of change dp/dt of the pressure fluctuation value, that is, the power value, is expressed by the S(p) value representing the strength of the pattern and the S(t) value representing the size. The value is expressed in three numerical values: the value and the N value, which represents the number of times pressure fluctuations occur, and these values are expressed as a unit time T.

The point is that it is integrated and displayed over time.

The configuration of the device of the present invention will be explained based on the drawings.
As shown in the figure, there is a slice amplifier 1 that passes the signal when the power signal exceeds a certain level, a V/F (voltage/frequency) converter 2 that converts the height of the power signal level into a higher or lower frequency, and the corresponding V A P counter 5 is provided which integrates the frequency output from the /F converter for a certain period of time.

Further, there is a comparator 3 that shapes the signal level into O and 1 levels, an AND gate 7 that allows the clock pulse to pass only when the signal shaped by the comparator 3 is at the 1 level, and an AND gate 7 that passes the clock pulse through the gate. A t-counter 8 for integrating clock pulses from the clock pulse generator 6 is provided.

Also, there is a timer 9 that starts operating depending on the level change of the signal shaped by the comparator 3, an N counter 11 that counts the number of times the signal from the OR gate 10 becomes 1 level, and the P counter 5, the T counter 8, and the N counter 11. A display 12 for displaying each value and a preset timer 4 for returning the counters 5, 8, and 11 to O at regular intervals are provided.

Next, to explain the operation of this device, in the block diagram of the embodiment shown in FIG.
/F converter 2 and comparator 3, and the frequency output from the V/F converter 2 is determined by the set time T of the preset timer 4.
.

is accumulated by P counter 5, and this value is S(p)
On the other hand, when the signal shaped by the comparator 3 is at 1 level, the clock pulse generator 6
The output clock pulse is passed through the AND gate 7 and the set time T of the preset timer 4 is reached.

The value is accumulated by the t counter 8 during the period S(t)
Display as value.

On the other hand, in parallel with the route connecting directly from the comparator 3 to the OR gate 10, the operation starts when the signal level from the comparator 3 changes from the 1 level to the O level, and the signal level is kept at 1 for the set time TN. It is connected to an OR gate 10 via a timer 9 that maintains and outputs the signal.

As a result, the signal passes through the OR gate 10 when either or both of the signal from the comparator 3 and the signal from the timer 9 is at the 1 level.

Further, the signal from the OR gate 10 is passed through an N counter 11 that counts the number of times the signal changes from O level to 1 level, and the preset timer 4 is set for a time T.

During this period, this is integrated and displayed as an N value.

Here, the timer 9 is installed so that when the signal changes to 1 level again within the TN time, the change is regarded as a series of pressure fluctuations with the previous change, and the N counter is not activated.

In other words, the S(p) value corresponds to the integral amount of amplitude when a pressure fluctuation greater than the set value occurs, the S(t) value corresponds to the integrated amount of time during which the pressure fluctuation occurred, and N is the amount of pressure fluctuation. This shows the number of times it has occurred.

However, if there is a pressure fluctuation that exceeds the slice level intermittently within a short period of time, the series of changes is counted as one time.

In addition, the setting time T of the preset timer 4.

It is usually desirable that the heating time be about 10 to 60 minutes. If To is made too long, there will be a large time delay when performing operation control actions that correspond to the digitized pattern, resulting in a problem that it will not be possible to follow changes in the operation.

Also, if it is too small, control actions will be taken frequently, causing a problem in which changes in operation cannot be confirmed.

If the set time TN of the timer 9 is too long, the value of the number of pressure fluctuations N will become small and the transition of the operating level will not be sufficiently controlled, so it is desirable to set the set time TN to within 60 seconds.

FIG. 3 conceptually shows the relationship between numerical values obtained by quantifying the pressure fluctuation pattern according to the present invention and the force fluctuation pattern.

In the case of fluctuation pattern A, the S(p) value is high, but the S(t)
The value will be lower.

In addition, in the case of pattern C, the S(t) value is large and S(
p) value becomes lower.

Pattern B shows almost the same S(p) and S(t) values.

The difference between these patterns is that the ratio of S(p) and S(t), that is, when S(p)/S(t) is 2 or more, pattern A is used, and when it is 1 or less, pattern C is used. In this case, it can be quantitatively classified as pattern B.

In other words, if you know the S(p) value and the S(t) value, you can understand the furnace condition.

The N value is a value that indicates the degree of each pattern A, B, and C, and is used as a criterion for determining whether to take action to restore the furnace condition to normal.If it is less than the preset standard value, the current condition is Monitor changes in N value while continuing operations,
If the N value exceeds the reference value, it can be used to take action to normalize the furnace condition by means suitable for that pattern.

By quantifying the pressure fluctuation pattern by using the apparatus of the present invention in this way, it is possible to quantitatively grasp information for stable blast furnace operation.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the wind pressure fluctuation pattern and the pattern when converted to power, Fig. 2 is a block diagram showing the configuration of the pattern digitization device according to the present invention, and Fig. 3 is the value after digitization and the wind pressure fluctuation pattern. FIG. 1 is a slice amplifier, 2 is a V/F converter, 3 is a comparator, 4 is a preset timer, 5, 8, and 11 are counters, 6 is a clock pulse generator, 7 is an AND gate, 9 is a timer, and 10 is a OR gate 12 is an indicator.

Claims (1)

[Claims] 1 A slice amplifier 1 that passes a power signal of fluctuations in furnace pressure such as blast pressure and shaft pressure during blast furnace operation when the signal exceeds a certain level, and a voltage that converts the output voltage of the amplifier into a frequency. a frequency converter 2;
A counter 5 that integrates the output frequency of the converter for a certain period of time.
, a comparator 3 that shapes the output voltage of the amplifier into 0 and 1 levels, and an AND gate 7 that allows a clock pulse to pass only when the output of the comparator is at 1 level.
and a counter 8 which integrates the clock pulses passed by the AND gate, an OR gate 10 which inputs the output of the comparator and the output of a timer 9 which produces a 1 level output for a certain period of time from the rise of the output, and the OR gate 10. Counter 1 that counts the number of times the output reaches level 1
1, and a display device for a pressure fluctuation pattern in a blast furnace characterized by being provided with a display 12 for displaying each value of these counters 5, 8, and 11.