JPS58204109A - Detection of leakage of cooling water from blast furnace tuyere - Google Patents

Abstract

PURPOSE:To detect the leakage of cooling water occurring in the failure of a blast furnace tuyere by determining the correlation between the difference between the feed flow rate of the cooling water for the blast furnace tuyere and the discharge flow rate thereof and the blast pressure for the tuyere. CONSTITUTION:The differential flow rate of cooling water for a blast furnace tuyere between the feed flow rate and discharge flow rate is measured with a pair of flowmeters installed to feed and discharge pipes for said cooling water. The correlation between said differential flow rate of the cooling water and the blast pressure for the tuyere is determined, and the magnitude in the inclination of the regression line or the coefft. of correlation is graphically dispalyed. The magnitude is compared with a control standard and the failure of the tuyere is discriminated. The leakage of the cooling water occurring in the failure of the tuyere is thus detected easily.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is a proposal for a method for detecting cooling water leakage from a blast furnace tuyere.

As a known technique for detecting blast furnace tuyere damage, a method is known in which a plurality of electromagnetic flowmeters are used to measure the differential flow rate of tuyere cooling water. This technique is used for tuyere damage. .

This method utilizes the phenomenon that water intrudes into the blast furnace and the flow rate of drainage water becomes smaller than the flow rate of water supply, and detects whether or not there is damage to the siding by using an upper limit alarm set on a differential flowmeter. However, in the case of this conventional technology, there are various cases of tuyere damage, so there is a problem that it is difficult to detect all damage simply by monitoring the upper and lower limits of the differential flow rate. there were.

In addition, when measuring the differential flow rate of cooling water, the following phenomena occur: ■ The differential flow meter swings to the negative side (water supply flow rate <drainage flow cover).

■ The differential flow meter repeats the normal value ('water supply flow rate - drainage flow rate) and lower limit value.

■) The differential flow rate repeats the normal value and upper limit value.

is possible. Of these, the reasons for the above ■ and ■ are that one is when there is an abnormality in the detection device, and the other is when air bubbles occur only in the drain pipe of the cooling waterway, but in the latter case. This will occur if the siding is damaged and the furnace gas does not get mixed into the cooling channel.

This is an impossible phenomenon, and in an actual blast furnace, the pressure of the cooling water is higher than the pressure and force inside the furnace, so it is difficult to imagine it under normal conditions.

Therefore, in such a case, the failure of the detection device, mainly the electromagnetic flowmeter, is first investigated.

When the phenomenon (2) occurs, it is not easy to determine whether it is due to tuyere damage or an abnormality in the detection device, and in this case as well, the detection device must be inspected first.

Here, if the cause of the phenomena ■, ■, and ■ is tuyere damage (small damage state), there is no problem with the detection device, and the cause of the failure cannot be investigated immediately. , it takes time to find the root cause. Moreover, even during metering, water continues to flood into the furnace from areas with minor damage to the siding, and the accompanying heat removal increases the coke ratio during blast furnace operation. On top of that,
Even if the damage is minor, if left as it is, it may eventually lead to major damage and require an emergency shutdown.

An object of the present invention is to provide a detection method that can be effectively used to accurately determine the damage to the siding when the damage is still small. - This is an effective method for minimizing leakage of tuyere cooling water by determining the strength of the correlation between the differential flow rate of drainage water and the tuyere blowing pressure. The details of the configuration will be explained below.

Figure 1 is a circuit diagram of the tuyere cooling water leak detection device.
The siding cooling water reaches the tuyere 10 from the water supply header 1 through a pipe passing through the stop valve 2°8.4, and from the tuyere 10 to the stop valve 6,
The water flows through a line passing through a pipe line 7 to a drainage gutter 9, and the supply/drainage flow rate at that time is measured by an electromagnetic flow meter 11, and a differential flow rate indicator/alarm meter is sent via an amplifier 12 to a drain gutter 9. 14 to display the differential flow rate. Note that the drainage flow rate is also indicated to the drainage flow rate indicator and alarm meter 18 through a similar measurement process.

On the other hand, the blast pressure, which is an approximate value of the pressure in the furnace around the tuyere, is determined by a pressure detector 16 installed in the hot air pipe 15.

It is detected and displayed on the pressure indicator 17. Multi-pen/
The trend recorder 18 is a device that selects the blowing pressure signal and any differential flow rate signal at any time. The 1-process computer 19 has a display device 20 and a typewriter device 21, and takes in various information about the blast furnace 1° (4) to manage and control the blast furnace operation. 1. When not measuring, close the stop valves 8, 4, 6.7, and close the stop valves 5, 8.
is opened, and the cooling water is sent directly to the tuyere 10 without passing through the flow meter 11, and also flows directly toward the drainage gutter 9.

According to the inventors' study of blast furnace operations in the past when tuyeres were damaged, it was found that the difference between the blowing pressure of hot air blown from the siding 10 and the differential flow rate between supply and drainage, as shown in Figure 2. It was found that there is a strong correlation. In other words, the slope of the regression line in the case of a normal stitch was almost zero, whereas the slope of the regression line in the case of a damaged stitch was -174. Therefore, by determining the slope a of this regression line, it becomes possible to easily determine whether or not the tuyere is damaged. The present invention was constructed based on the above knowledge (1).In this point, when the tuyere is damaged and the difference between the amount of water supplied and the amount of water discharged, that is, the differential flow rate shows a negative value, hot air is This is when the water enters the water passage space and generates bubbles in the cooling water.

It appears that the amount of drainage has increased. On the other hand, when the difference 1 flow rate is positive, it means that water is flooding into the furnace from the damaged tuyere, and the correlation coefficient also displays a negative value.

Therefore, there are positive and negative correlation coefficients, and the slope of the regression line y2 shown in Figure 8 is when the differential flow rate is negative, but conversely, when the differential flow rate is positive, the regression line is the opposite slope. It becomes a slope. This graph is displayed on the display device 2o.

Therefore, the magnitude of the above-mentioned correlation coefficient or the degree of slope of the regression line is proportional to the i degree of tuyere failure at the same time, and the magnitude of the correlation coefficient is proportional to the degree of i degree of tuyere failure. It is possible to determine whether or not there is damage to the siding. For this purpose, the above-mentioned coefficient at the time of siding damage is determined in advance as a control value l-1 from past operation results and input into the calculator 19.

In order to determine the strength of the correlation in the present invention, in addition to comparing the magnitude of the slope a of the regression line described above, damage to the siding may be determined based on the degree of the correlation coefficient.

Incidentally, the slope a of the regression line is calculated as follows.

Melt. First, from past operation data, in a scatter diagram where the blowing pressure is lX and the -force difference flow rate is y, the coefficient a of the regression line y=ax+b is determined by the least squares method. The way to obtain it is to input the measured values of the differential flow rate and one air blowing pressure of all n pieces (40 pieces) into the process computer 20 in a rotary format (taking new data at regular intervals and discarding the oldest data). The coefficient a of the regression line for each tuyere is determined by the following formula: ("X xi ) - n "X If it is calculated and displayed each time on the order of days, it is possible to accurately detect the presence or absence of a mouth break by looking at the magnitude of the coefficient a, and this may be displayed as an alarm.

Example: Blast furnace volume: 4.500 fi8, number of tuyere: 40, cooling water supply amount: 85 m8A, wall blowing pressure: 4.2-2,
G.

(7) 21... Typewriter device.

In operation at ~4-61J/crn2・G, the upper and lower limits of the correlation coefficient a were set to ±8, and the operation was performed while calculating the correlation 8 times/day. and could be detected quickly. In the end, the wall damage did not lead to major damage, and stable blast furnace operation was achieved.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram of the tuyere cooling water leak detection device used in the present invention, and Fig. 2 is a graph of the correlation between the blowing pressure l...force and the differential flow rate displayed on the display device81...・Water supply header, 2...stop valve, 8...stop valve, 4...stop valve, 5
... Stop valve, 6 ... Stop valve, 7 ... Stop valve, 8 ... Stop valve, 9 ... Drain gutter, 10 ... Tuyere, 11 ... Flowmeter, 12. ... Increase, width gauge, 18... Drainage flow rate indicator and alarm meter, 14... Differential flow rate indicator and alarm meter, 15... Hot air pipe, 16
...Pressure transmitter, 17...Pressure indicator, 18...
Multi-pen trend recorder, 19... Process calculator, 20... Display device. (8) Patent applicant Kawasaki Steel Corporation Figure 1 Figure 2 Bore pressure 7'7 (Kf/cm)

Claims (1)

[Claims] 1. In the method of detecting cooling water leakage by measuring the cooling water flow rate and the water difference flow rate using a pair of flowmeters installed in the supply and drain pipes of the blast furnace tuyere cooling water, Determine tuyere damage by determining the correlation with the tuyere blowing pressure and comparing the slope of the regression line in the graphic display or the magnitude of the correlation coefficient with the control standard from the obtained correlation.1. A method for detecting cooling water leakage in blast furnace siding, characterized in that: