JPS6032682B2 - Method for measuring conditions inside blast furnaces, etc. - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring the condition inside a blast furnace, etc., and specifically, it relates to a method for measuring the temperature and gas pressure of a charge in a blast furnace or a shaft furnace (hereinafter referred to as a blast furnace, etc.), and In order to measure the conditions inside the furnace such as collecting samples, the water cooling lance inserted almost horizontally from the furnace wall is moved at a moving speed that limits the residence time in the furnace to a predetermined value. It concerns the method of measurement.

Generally, to measure the inside conditions of a blast furnace, etc., a water lance is inserted approximately horizontally from the furnace wall, and the neck is measured through this lance.

Measures temperature and pressure, collects gas samples, etc. In this case, the lance is easily deformed by the load of the charge descending inside the furnace, and to prevent this, a lance with a large outer diameter of 20 mm or more is usually used, so that the lance inside the furnace is The layered structure consisting of the ore layer and the coke layer is disturbed, creating a major hindrance to blast furnace extraction. That is, the lance is water-cooled, and because of the delayed response of the thermocouple therein, the lance is typically stopped at 4 to 10 radial locations within the furnace, the temperature is measured at each stop, and the gas sample is sampled. Collect.

For this reason, one measurement takes more than 5 minutes, and the lance has a large diameter, which poses problems in terms of blast furnace operation. To explain in more detail, the large outer diameter of the lance inserted into the furnace not only increases the manufacturing cost of the measuring device, that is, the sonde, but also has the following negative effects on blast furnace operation.

Generally, in a blast furnace, ore and coke are alternately placed in bags to form a layered structure in which ore layers and coke layers are alternately stacked in the furnace.

This layered structure has the advantage that even if the air permeability deteriorates when the ore layer softens and fuses, the gas in the furnace passes through the coke layer, so the air permeability of the entire blast furnace does not deteriorate. Therefore, maintaining the layered structure and not disturbing the layered structure is important for blast furnace operation. However, the respective thicknesses of the ore layer and coke layer formed in the furnace are usually
It varies slightly in the radial direction of the furnace, but on average, it is about 60 to 80 degrees when inserted into the furnace.

In addition, since the cross-sectional area of the furnace expands downward, the thickness of each layer decreases as the rhombite descends in the furnace, and in the belly where the cross-sectional area of the furnace is maximum, It will be about half the value of 300 to 40 m. In addition, on the other hand, the rate of descent of the diamonds is about 10 feet per minute at the top of the furnace, and about 5 feet per minute at the bottom of the furnace.
As described above, if the lance stays in the furnace for a long time and has a large diameter, the layered structure of the contents in the furnace will be significantly disturbed by insertion of the lance. For example, Figure 1 shows that in a blast furnace with an internal volume of 4500, when the situation inside the furnace is measured by inserting a lance 2.9 mm below the bag filling surface, the temperature of the gas inside the furnace is measured and the gas sample is collected. This is a record chart of the furnace top gas analysis values before and after the test was carried out. In Fig. 1, a indicates N2 (%), and b indicates C0.
2 (%), c indicates C○ (%).

In this chart, the gas analysis value changes before and after the measurement with the lance indicated by the symbol A, and as is clear from this, if the measurement is performed using the conventional method, this adversely affects the blast furnace operation. The purpose of the present invention is to solve the above-mentioned drawbacks. Specifically, the present invention uses a lance inserted into the furnace to suppress the disturbance of the layer structure in the furnace to a minimum of 4.0, and to prevent it from adversely affecting the operation of the furnace. We propose a method to measure the internal situation.

The method of the present invention will be explained in detail below. First, a lance is inserted almost horizontally from the bottom of the blast furnace, etc., and this lance satisfies the following '1' and [2- expressions] in relation to the thickness of the contents layer in the furnace, its descending speed, etc. move it so that
In the darkness of this movement, we will measure the temperature and pressure inside the furnace, collect gas samples, etc. 0.5xL>(dv・t)...[
1) v・t＜0.1・・・・・・
-(2) In addition, in the above formulas [1} and '2}, Lo, d, v, and t are as follows.

L: Thickness of the thin rhombus layer among the ore layer and coke layer (m
) d: Outer diameter of the lance (m) v: Lowering speed of the charge in the furnace (mm/sec) t: Residence time of the lance (sec) In this way, the residence time in the furnace is limited to (t). If the lance is moved continuously at a moving speed of
It is possible to measure the layered structure of the charge without exposing it, and the outer diameter (d) of the lance can also be made smaller.

Generally, in order not to disturb the charge layer structure in the furnace, it is preferable to configure the outer pot (d) of the lance to be as small as possible to reduce the time (t) that the lance stays in the furnace.

The thickness of the layer (L) affected by insertion of the lance is expressed by the following relational expression based on the lance's outer diameter (d), the residence time in the furnace (t), and the rate of descent of the rhomboids (v). It will be done. L:d
+v●t For example, d=0.3 skin, v=0.00167 wind/sec,
If t=30 current sand, L=0.8 skin is obtained, and by comparing this value with the thickness of the rhombus layer in the furnace, the influence of lance charging can be determined.

In other words, if the layer thickness (L) is reduced by 4 mm, the effect of lance insertion on the horizontal structure of the layer will be smaller, and the effect on the layer structure will actually fall within the operationally acceptable range. The size of the thickness (L) is 1'2 or less of the thinner thickness (L) of the ore layer or coke layer in the furnace, and furthermore, 1'3
This is preferable because it can almost eliminate its influence.

However, in order to satisfy this condition, it is first necessary to reduce the outer diameter (d) of the lance;
) is reduced, the strength of the lance decreases, and the lasso is supported on only one side near the furnace crash, like a so-called one-sided beam, which may cause permanent deformation in the lance. This is the reason why the conventional lance is so large.The reason why the lance is made large in diameter is that the lance can have sufficient strength to support the load of the diamond-shaped object. Regarding this point, the present inventor has considered the nature of the load applied to the lance from the rhombus in the blast furnace, and based on this, the time the lance stays in the furnace is limited, and the load applied to the lance is greatly reduced. It was found that it can be reduced during

For example, FIGS. 2a and 2b are explanatory diagrams showing the load state of the lance due to the bag contents in the furnace. In particular, FIG. The lance 3 is shown inserted into the container 7 from the furnace wall 6.

In this case, the lance 3 is supported outside the furnace at the fulcrums 1 and 2, and is in a so-called one-sided beam state, and the lance in the charge is subjected to equal loads 4 of the bag from above and below, downward and upward. Since a uniformly distributed load consisting of 5 is acting, the load on the lance is negligible and the strength of the lance is not an issue in this case. On the other hand, FIG. 2b shows the state of the lance when the pouch 7 moves at a speed (v) for a time (t). Since the load 5 decreases, a downward load 4 is applied to the lance 3 from above, and the upper and lower loads 4,
The balance of 5 is lost. In this case, the load applied to the lance 7 is determined by the amount of movement v・t of the bagged material 7 and the amount of downward movement of the lance 3 in the vertical direction. When the load is zero and the lance 3 does not move and only the charge 7 moves downward, a downward load 4 is applied to the lance 3 from above, and conversely, the amount of downward movement of the lance 3 corresponds to the downward movement of the charge. If it is larger than the amount, an upward load is applied to the lance 3 from below. Now, considering the time when the amount of movement v・t of the bagged material 7 is small, in the area close to the furnace wall 6, the amount of movement of the lance 3 is limited by the fulcrum 2, so the lance has a downward direction. A load of 4 is applied. Therefore, the lance 3 is bent downward by this downward load 4, so that the lance 3 moves more than the charge 7 near the tip of the lance 3, and an upward load 5 is applied thereto. Furthermore, as the time (t) that the lance 3 stays in the furnace becomes longer, the downward load 4 increases and the upward load 5 decreases, so the downward load 4 applied to the entire lance 3 increases. In short, the downward and upward loads 4 and 5 applied to the lance 3 in the furnace depend on the residence time of the lance in the furnace (t) and the rate of descent of the charge in the furnace (v), and the product of both ( By reducing v·t), the load applied to the lance can be reduced, and measurements can be made even if the outer diameter of the lance 3 is reduced. Based on this knowledge, the inventor conducted an experiment to determine the limit of the usable movement distance (vt) of the lance, and found it to be 0.1. In addition, in order to satisfy the conditions shown in {1} and ■ above and move the lance 3 along the horizontal level for measurement, the residence time in the furnace near the top of the furnace (
t) is preferably limited to within 60 seconds, and in order to measure temperature etc. with high accuracy under these conditions, it is necessary to use a wide beam radiation beam from a solid or liquid, rather than a thermocouple type as in the conventional example. It is preferable to use an optical thermometer, etc., which utilizes a thermometer and has a long response speed.

That is, FIG. 3 is a layout diagram of an example of a measuring device for carrying out the method of the present invention, and in FIG. 3, reference numeral 3 indicates a lance;
6 indicates a furnace wall, in which 6a is a refractory material and 6b is a refractory material.
is a stave, 6c is a shell, and the lance 3 is driven in the horizontal direction by a drive device 8.

This lance 3 is provided with a gate valve 9 and a flexible joint 10, and is further sealed off by a gas seal mechanism 11. Further, the details of the structure of the lance 3 are as shown in FIG. 4, in which a cooling pipe 12 is provided, and cooling water is introduced from one end 12a of the cooling pipe 12, and this cooling water is supplied to the lance tip 3a. The lance 3 is cooled by the cooling water passing through this path. The temperature inside the furnace is measured by receiving a beam of radiation from the charge in the furnace through a measurement window 14 attached to a lance 3, and transmitting the beam through an optical fiber 15 to, for example, a two-color thermometer 16. . Furthermore, the pressure inside the furnace is measured and the gas sample is collected through an opening 17 attached to the lance, and the pressure and gas sample are passed through a pressure pipe 18 to a pressure measuring device 19 and a gas sampling device 20, respectively. Send it to perform pressure measurements and sample collection. Although only one pressure guide tube is shown above, in the case where pressure measurement and gas sampling are performed simultaneously, it is preferable to provide one more set of openings and pressure guide tubes.
Furthermore, when measuring by moving the lance as described above, it is necessary to move the lance continuously without stopping in the middle except when changing the direction of movement. That is,
If the lance is stopped midway through residence in the furnace, a significantly larger load will be applied to the lance than if the load due to the falling charge was transmitted to the lance by static friction. This can be seen from the fact that when the lance starts moving after being stopped in the furnace for a considerable period of time, the load instantly becomes less than half of what it was before the lance started moving. Therefore, it is preferable to operate the lance continuously, except for temporary stops when switching from insertion to removal.If the lance is moved continuously, the load on the lance can be reduced, and even if the lance is small in diameter, It is also possible to perform sufficient measurements. As explained in detail above, the method of the present invention measures the condition inside the furnace by moving the lance in relation to the descending speed of the charge in the furnace. It becomes possible to measure the temperature and pressure inside the furnace, and to sample gases without causing any disturbance to the layer structure that would cause operational problems.

Moreover, the measuring device can be made smaller and the equipment cost can be reduced.
Although the method of the present invention is mainly used in blast furnaces, it can also be applied to shaft furnaces, cupolas, and the like.

[Brief explanation of the drawing]

Figure 1 is a graph showing the changes in the analysis of each composition gas of blast furnace furnace gas, Figure 2 a and b
3 is an explanatory diagram of the state of action of the load from the rhombus on the lance in the furnace, FIG. 3 is a layout diagram of an example of a measuring device implementing the present invention, and FIG. 4 is a cross-sectional view of a part of the lance. FIG. Codes 1, 2...Fully point, 3...Lance,
4,5. ．． ...Load, 6...Furnace wall, 7...
...Charge, 8...Drive device, 9...
Gate valve, 10...Flexible joint, 11.
...Gas seal mechanism, 12...Cooling pipe,
13...Drain port, 14...Measurement window, 15...
...Optical fiber, 16...Two color thermometer, 17
Sekiguchi section, 18... Impulse pipe, 19... Pressure measuring device, 20... Gas sampling device. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] 1. Outer diameter (dm) from the wall of a blast furnace etc. to the contents inside the furnace
The lances are inserted almost in parallel, and the lances are inserted so that the residence time (t seconds) in the furnace is within 60 seconds and the equations (1) and (
2) 0.5L_0>(d+V
・t)...(1)V・t<0.1...(2) However, L_0 is the thickness (m) of the thinner layer of the ore layer and coke layer that are formed alternately in the furnace, and V is A method for measuring the condition inside a blast furnace, etc., which is characterized by continuously reciprocating the charge at a descending rate (m/sec) in the furnace, and measuring the condition inside the furnace such as temperature measurement and gas sample collection during this period. .