JPS6026801B2 - How to control shaft furnace operation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for controlling the operation of a shaft furnace, which measures the temperature of the outer side surface of the refractory coating of the furnace and controls the operation of the furnace based on changes in temperature. Regarding how to modify parameters.

The control of the operation of shaft furnaces, in particular blast furnaces, is generally carried out on the basis of gas analysis at the top of the furnace, the draft pressure and the gas pressure at various levels in the blast furnace, and the analysis of the cast iron and slag cast in the bottom. Another method is to observe the rhombus in the upper part of the blast furnace.

The temperature and temperature distribution in the upper part of the bag, the shape and arrangement of the bag, and the uniformity of its descending slope are observed, and operation is controlled based on this observation. This method, whether continuous or discontinuous, only provides general information about the phenomena actually occurring inside the furnace, and only rarely identifies areas where undesirable phenomena are occurring. I will only confirm it.

There are ways to use blue to at least partially correct these deficiencies. This involves injecting sound into the interior of the charge to obtain more accurate information. However, the information obtained by this method can only draw valid conclusions in a very localized manner, and furthermore, it is difficult and difficult to draw such conclusions.
It is slow and slow.

Another method is to measure the temperature of the furnace wall.

This measures the temperature of the cooling water in the cooling box or water stave installed on the side wall of the furnace in order to prevent undesirable overheating of the refractory material that constitutes an important part of the side wall of the furnace. It brings out the. However, the information obtained from this is very qualitative and does not very clearly indicate irregularities in the uniformity of the operation of the furnace, and in some cases does not indicate the impending danger of other serious perforations. It is something. The object of the present invention is to provide a method by which accurate information about the distribution of temperature around the whole enclosure of a bag can be continuously obtained, which method can be used to detect the formation of shelves, ventilators or places of abnormal wear. It informs of existence, disappearance or movement.

According to the present invention, one horizontally extending zone is selected on the outer side surface of the internal refractory coating, the temperature is measured at multiple points within this zone, and an actual temperature distribution map of this zone is created.
Observe how this temperature distribution map changes with time, detect the cold and hot areas in the zone, detect how the cold and hot areas change with time, and detect how the cold and hot areas change with time. This is a method of comparing the actual temperature distribution map at each time with the desired temperature distribution map at each time, and using the information obtained from this, to take all the correct measures deemed necessary to maintain or restore good operation of the furnace. .

The present invention will be described in more detail below with reference to the accompanying drawings.

The method of the invention is applied to a blast furnace 1 shown diagrammatically in FIG.

The side wall of the blast furnace is divided into several horizontal zones, each zone consisting of two horizontal planes perpendicular to the vertical axis of the furnace, and a number of temperature measurement points are provided, preferably in zone 2, which includes the furnace belly. In the belt castle 2, as shown in an enlarged view in FIG. 2, metal plates P are arranged at, for example, six heights, indicated by 3 to 8, over the entire length. The details are shown in Figure 3.
A metal plate P is arranged between the internal refractory coating 9 and the thermal isolation layer 10. Thermal isolation layer 10 is covered by an outer metal jacket 11 . The metal plate P is vertically provided with conduits 12 for passing a cooling fluid (for example water) and is referred to as a water-cooled stave. The conduit 12 is connected to the adjacent upper and lower metal plates P by means of suitable connections 13 (for example bendable joints). A thermocouple 14 is provided in the middle of the inner surface of each metal plate P, so that the thermocouple 14 measures the temperature of the outer side surface of the internal refractory coating. Note that this side surface may be in direct contact with the external metal jacket 11, but in the illustrated embodiment, the side surface is in direct contact with the metal plate P and the thermal isolation layer 10. As understood from FIG. 2, there are a large number of temperature sampling points (that is, thermocouples 14) in the belt castle 2 at equal intervals in the vertical and horizontal directions.
Referring to Fig. 4, the position of the temperature sampling point is determined at the angle indicated by the machine axis L (360 degrees around the entire circumference) and the height indicated by the vertical axis d (the height is 100 degrees, the ratio is one horizontal band). 2), record the temperature at each temperature sampling rule at the corresponding position in Figure 4, create a temperature distribution map, and connect the isothermal points to draw an isothermal curve. The thus obtained temperature distribution map of FIG. 4 shows the temperature distribution of the castle 2 at a certain time. To further explain Fig. 4, 50℃ from 100℃ to 400℃
An isothermal curve is drawn at intervals of , and it can be seen that the temperature in most areas of this belt city 2 is approximately 100q0 to 150qo.

And these are very gradual temperature changes. From this, the cooling of the area of the belt castle 2 is effective and substantially uniform. This means that there are no abnormalities in these areas of the furnace. By the way, the upper part of band 2 (height Q)
There are two areas where the temperature reaches approximately 400°C, and the temperature gradient near these areas is steep. Note that one of these areas is at oo (or 360o) of the machine axis L, and the other is at 1200. The occurrence of such hot spots is due to the rapid falling off of the hanging (bags, mainly carbonaceous materials) accumulated on the furnace wall, or due to localized gas flow in the hangings. Which of these is the cause can be determined by examining changes (over time) in the temperature distribution map. In any case, attention must be paid to the fact that the cooling system risks being pushed beyond its resistance limit. Although no particularly cold areas appear in Figure 4, the occurrence of cold areas may be due to large hangings in the internal refractory sheathing or insufficient circulation of rising gas around them.

The formation of the shelf gradually increases the wall thickness and reduces the temperature on the order of 0.4 qo/min or lower;
Conversely, removing shelves is 3. There is a rapid temperature rise on the order of 1/min or more.

Such temperature fluctuations can be found by observing the time course of the temperature distribution diagram according to the present invention. Therefore, by examining this temperature distribution map, the following conclusion can be drawn.

In comparison, the actual temperature distribution map should ideally correspond to the homogeneous portion of the charge and its reaction as well as the controlled cooling of the water-cooled staves by the cooling box. If different, 1 for particularly cold areas, [11 those cold areas signal the presence of thick shelves that may cause rapid shelf shedding.

Such shelf shedding can be observed by a sudden increase in temperature in the area. [2- These cold areas are in contact with parts of the blast furnace charge where the rising gas is not sufficiently circulated. This can be made to see if the area remains cold. '3} These cold areas are the result of insufficient or accidental air blowing in the vanes that are perpendicular to the area.

This induces control to take place at this location. (b) Regarding particularly hot areas, '11 These hot areas are places where shelf shedding occurred suddenly.

This shedding is discovered by the appearance of hot symptoms in this area. ■ These hot zones are affected by gas cavities passing through the charge adjacent to them.

In order to correct the anomalies obtained by studying said temperature distribution map in this way, it is possible to correct in the long term, for example by modifying the composition and/or distribution of the charge, and/or in the short term, by e.g. Modifications to the parameters or parameters of the hydrocarbon injection are taken.

Such modifications are not based on a single temperature map;
This is the result of comparing and examining many temperature distribution maps at various points in time.

This is because changes in the temperature distribution map over time provide more information to the operator and let him or her know what the abnormality is caused by. Therefore, workers can take the most appropriate measures. Observation of the temperature distribution map and its change over time provides the worker with the following information:

m Estimate the residual thickness of the refractory coating of the blast furnace, estimate the uniformity and distribution of the gas rising inside the blast furnace, and approximately estimate the location of the melting zone of the charge in the blast furnace.

In short, the present invention provides an accurate control of the regularity of the blast furnace operation, and also recognizes blast furnace operation accidents, such as shutdowns, faults in the cooling system, etc., from the first stage of the appearance of these abnormalities. It helps to make it happen.

Although the method of the present invention has been explained using one example as above, the essence of the method of the present invention is as follows.

Thus, the essence of the method of the invention is that the internal refractory coating in at least one horizontal zone of the furnace wall of a shaft furnace (e.g. between the height 1 and 2 and extending around the furnace for 3600 mm) Using a temperature sensor (probe) to measure the temperature of the outer side surface of creating a temperature distribution map; estimating the condition inside the furnace corresponding to the belt castle from the hot or cold areas appearing in the temperature distribution map and the state in which they change over time;
and, in order to eliminate the abnormality observed on the temperature distribution map, apply any means deemed useful in the vicinity of the diamond inlet or the air outlet, and in the vicinity of the possible inlet as the case may be, or in both places at the same time.
It is to take.

According to one advantageous variant of the method of the invention, following the production of the temperature map, isothermal curves are drawn thereon in order to facilitate the interpretation of this temperature map.

The temperature sensors are regularly distributed in the belt being devised and are arranged, for example, on the inner surface of a water-cooled metal plate (water-cooled stave) and are preferably placed between the inner refractory cladding and the outer metal cladding, said water-cooled metal Preferably, the plates are arranged next to each other so as to form one complete circumference in said band.

Said band castle can be at any height of the furnace wall, but in the case of blast furnaces it is advantageously taken to include the hearth, and one other band castle is located above and below this area. It is preferable to do so.

[Brief explanation of the drawing]

FIG. 1 is a diagram schematically showing a furnace 1 to which the present invention is applied. FIG. 2 is an enlarged view showing the arrangement of the metal plates P arranged in the belt castle 2 of FIG. 1. FIG. 3 is a vertical cross section showing a state in which metal plates P and thermocouples 14 are arranged in the furnace.
It is a figure which shows a horizontal cross section and a side cross section. FIG. 4 is a diagram showing a temperature distribution map of the belt castle 2 obtained by the thermocouple 14. In the figure, 1 is a blast furnace, 2 is a belt castle including the furnace belly,
3 to 8 are six heights that are an enlarged version of the belt castle 2, 9 is an internal refractory coating, P is a water cooling stave, 10 is a thermal isolation layer, 11' is an external metal exterior, and 14 is a thermocouple. Figure 1 Figure 3 Figure 2

Claims (1)

[Claims] 1. A method for controlling the operation of a shaft furnace comprising an outer metal jacket and an inner refractory coating, comprising: selecting one horizontally extending zone on the outer side surface of the inner refractory coating;
Measure the temperature at multiple points in this zone, create an actual temperature distribution map in this zone, observe changes in this temperature distribution map over time, detect cold areas and hot areas formed in the zone, and do the same. Detect the changes in the cold and hot areas with time, compare the actual temperature distribution map of each change with the desired temperature distribution map of each change, and compare the above two temperature distribution maps between each change with time. A method for controlling the operation of a shaft furnace, characterized in that at least one furnace operating parameter is modified to eliminate any differences between temperature profiles. 2. The method according to claim 1, wherein the shaft furnace is a blast furnace. 3. The method according to claim 1 or 2, wherein an isothermal curve is drawn in the temperature distribution map. 4. A water-cooled stave is disposed between the external metal jacket and the internal refractory coating so as to cover the entire side surface of the zone, and a temperature probe is disposed between the water-cooled stave and the internal refractory coating. 4. A method according to any one of claims 1 to 3, characterized in that they are arranged regularly on the side surface of the zone.