JPH0233085B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for measuring heat flux (hereinafter simply referred to as heat flow) within a refractory wall. This invention relates to a method for measuring bundles.

The furnace wall of a blast furnace is made of a thick layer of refractory material formed on the inner surface of the iron shell, but wear due to long-term continuous use is unavoidable. Detection is an essential management item in order to maintain stable blast furnace operation and to extend the life of the blast furnace by repairing the firewall. In addition, steady monitoring of thermal fluctuations within the furnace can be used to stabilize blast furnace operations as a furnace condition diagnosis technology, such as estimating furnace heat loss, early detection of cooling inside the furnace, and estimation of gas flow around the furnace. This will serve as an important guideline for achieving this goal. If it is necessary to estimate the internal condition or the extent of wear and tear on the wall surface of equipment such as this, where the interior cannot be viewed directly, it is necessary to embed some kind of sensor in the wall and make a judgment based on the thermal information from the sensor. The method is generally adopted.

However, although there are various differences in the structure of the sensors, the methods that have been adopted so far all involve embedding multiple sensors so that the length of the temperature measurement point varies in stages to measure the temperature distribution inside the wall. It is something to be measured. That is, since a plurality of temperature values obtained across the wall thickness are simply used as raw thermal information, estimation of the furnace internal situation often lacks accuracy. For this reason, there was an urgent need to develop technology to directly measure the state of heat transfer in the wall thickness direction.

By the way, in order to directly measure the state of heat transfer,
It can be said that it is most preferable to understand the heat flow itself, that is, the heat flow distribution in the wall thickness direction.

On the other hand, regarding the principle of heat flow measurement itself, for example, as shown in Figure 1, a heat flow meter A (however A1
is a thin thermal resistor and A2 is a covering material) is buried (or attached to the outer surface of the fireproof wall W), and the heat flow Q is calculated using the following equation (1) using the detected temperature difference ΔT between both sides. The principle method is already well known and a number of heat flow meters have been developed.

Q=F・λ／DΔT...(1) Q: Heat flow λ: Thermal conductivity of thin thermal resistor D: Thickness of ΔT; Temperature difference between both sides of F: Thermal conductivity of fireproof wall λ _W and It is a function of the ratio to the thermal conductivity λ of the thermal resistor, and represents the magnitude of thermal disturbance.

However, with this method, it is only possible to grasp changes over time in the heat flow that passes within a short section at the location where the heat flow meter is buried. That is, the heat flow distribution in the wall thickness direction is simply estimated using a heat flow calculation value based on the temperature difference ΔT over a certain short distance in the wall thickness direction. In other words, it does not measure the heat flow distribution itself in the wall thickness direction, and since the influence of thermal turbulence based on the F term cannot be ignored, it is necessary to directly measure the state of heat transfer in the wall thickness direction with high accuracy. I can't. Moreover, conventional buried heat flow meters have a plate-like shape and can only be installed when refurbishing or constructing a furnace.

Furthermore, when the furnace wall wear progresses to the point where the heat flow meter A is buried, the function of the heat flow meter A as a thermal information sensor will be significantly impaired or completely eliminated, making the measurement of heat flow distribution completely unreliable. It becomes something that does not exist. Therefore, there is a big problem in terms of ensuring continuous measurement. Furthermore, in the surface adhesion method, the reliability is extremely low because the measured values vary depending on the outside temperature, wind, etc.

The present invention has been made in order to eliminate these drawbacks of the prior art, and specifically aims to provide a method that can accurately and continuously measure the heat flow distribution in a specific direction in a refractory wall, especially in a blast furnace wall. do.

However, the method for measuring heat flux in a fireproof wall according to the present invention includes a fireproof wall that has at least three or more temperature-sensing parts from a specific direction, and has approximately the same thermal conductivity as the firewall material. By embedding temperature detection sensors and calculating the heat flow between adjacent temperature sensing parts based on the temperature measurement results detected by each temperature sensing part, it is possible to determine the heat flow distribution in a specific direction within the fireproof wall, that is, the state of heat movement. The main point lies in the fact that it allows for direct understanding of the situation.

The configuration and effects of the present invention will be described below with reference to the drawings of the embodiments, but the embodiments below are merely representative examples, and the present invention may be implemented with appropriate changes in accordance with the spirit of the preceding and following. included in the technical scope of FIG. 2 is a schematic explanatory diagram when the method of the present invention is applied to the walls of blast furnaces, and B indicates a temperature detection sensor (hereinafter simply referred to as a sensor) used in the present invention.
The sensor B is embedded through the iron shell C and the stamp layer D to the inner surface of the fireproof wall W. An example of sensor B is shown in FIG. 3 (a partially cutaway perspective view) and FIG. 4 (a developed cross-sectional view equivalent to FIG. 3). That is, numeral 1 in the figure is a jacket sheath tube that serves as a protective tube for the entire sensor B.
2a is a sheath type thermocouple, which can of course be replaced with a sheath type resistance thermometer. The thermocouple 2a
A pair of metal wires 4, 4' exhibiting a thermoelectric effect are inserted through the sheath, and their tips are connected to measurement contacts, that is, temperature sensing parts P1, P2,...P5, P6 (hereinafter typically referred to as is written as P). These temperature-sensing parts P are configured to occupy different positions in the length direction, and in the figure, the positions in the length direction are changed at approximately equal pitches from the inside of the furnace to the side of the shell, and the positions P1, P2,... P6 is provided.
Note that this pitch is arbitrary and may of course be random, but a preferred design example is to reduce the pitch between the temperature sensing parts inside the furnace in order to improve the accuracy of estimating the degree of wear and tear on the refractory wall W. It can be said. A sheathed thermocouple 2b made of the same material as the sheathed thermocouple 2a is connected as a dummy to the tip of the temperature sensitive part P (6 in the figure indicates a connection part). Therefore, since the geometric cross-sectional configuration of sensor B is exactly the same,
The thermal conditions, that is, the temperature measurement conditions in each temperature sensing portion P become constant.

Further, 3 is a fire-resistant insulating material filled in the outer sheath tube 1, which ensures the durability of the sheathed thermocouple 2a and improves heat transfer in the length direction within the sensor B. The temperature measurement accuracy in the length direction is improved. In order to reduce heat transfer in the longitudinal direction, it is recommended that the outer sheath tube 1 be made of a thin-walled tube made of a material with low thermal conductivity.If corrosion resistance is also taken into consideration, stainless steel or Inconel etc. is preferred. In this way, together with the strength effect based on the characteristic structure of the double-sheathed pipe, temperature measurement at each temperature sensing part P, which is a prerequisite for heat flow calculation, can be carried out reliably and with high precision over a long period of time. Can be done.

Another example of sensor B (sensor B') is shown in the fifth surface (partially cutaway diagram) and FIG. 6 (cross-sectional view taken along the line -- in FIG. 5). i.e. sensor
B′ is each temperature sensing part P1, P of sensor B as described above.
Disk-shaped fins 8a, 8b,... are provided corresponding to the fins 2, . and is covered with a blinding board 12. Therefore, if such a sensor B' is used, it is possible to measure the temperature reliably and with high precision even when deposits are generated or grow on the inner surface of the fireproof wall, which is convenient.

Therefore, by sending the temperature measurement results detected by the temperature sensing parts P1, P2,...P5, P6 of the sensor B or sensor B' to a heat flow calculation indicator not shown in the figure, it is possible to control the temperature between adjacent temperature sensing parts. The heat flow Q1, Q2,
..., Q5 can be simultaneously measured with high accuracy. Therefore, in the example shown in Fig. 2, it is possible to directly grasp the state of heat transfer in the thickness direction of the fireproof wall W.
The degree of wear and tear on the inner surface can be estimated more accurately and quickly over a long period of time. At the same time, it is possible to estimate the heat loss of the furnace body and understand the situation inside the furnace with high accuracy.

A means for further increasing the value of the present invention (value in terms of heat flow measurement accuracy) will be described below. That is, in the heat flow calculation indicator described above, each heat flow Q1, Q2, .

Qi = Fλ _B /Di (Ti - Tj) ... (2) However, the subscripts i and j mean the i-th and j-th parts, respectively, counting from the inside of the furnace, and Qi; the i-th temperature sensing part and j Heat flow between the th temperature sensing parts (kcal/m ² h) Ti: Temperature measurement value at the i th temperature sensing part (°C) Tj: Temperature measurement value at the j th temperature sensing part (°C) Di: i th temperature sensing part Distance between hot part and jth temperature sensing part (m) λ _B ; Thermal conductivity of sensor B (kcal/m・hr・℃) F; Thermal conductivity of firewall W λ _W and the thermal conductivity of sensor B It is a function of the ratio to λ _B and represents the magnitude of thermal disturbance.

Q1=Fλ _B /D1・(T1−T2) ……(3) Q2=Fλ _B /D2・(T2−T3) ……(4) Q3=Fλ _B /D3・(T3−T4) ……(5 ) Q4=Fλ _B /D4・(T4−T5) ……(6) Q5=Fλ _B /D5・(T5−T6) ……(7) And comparing Q1 to Q5, we find that the heat flow is However, in this case, the term related to accuracy in equations (2) to (7) above is the F term.
The key to further improving accuracy is how small the influence of the term can be suppressed. By the way, the thermal disturbance expressed by F=f(λ _W /λ _B ) can be understood as follows. That is, (a) when λ _W > λ _B , (b) when λ _W < λ _B , (
c)
To explain the state of thermal disturbance in each case of λ _W ≒ λ _B based on Figure 7 A to C, first, in case (A), the heat flow around sensor B is dissipated within the fireproof wall W. This tendency is particularly noticeable in the case of λ _W ≫ λ _B , so that it cannot be expected that the accuracy of heat flow measurement by sensor B will be improved. Next, in case (b), conversely, the heat flow existing within the fireproof wall W around sensor B is likely to be focused within sensor B, and this tendency is particularly noticeable when λ _W ≪ λ _B. In this case as well, no improvement in accuracy can be expected. However, in case (c), the heat flow around sensor B is almost parallel to sensor B, so the influence of thermal turbulence can be almost ignored. Therefore, in order to improve accuracy, sensor B should be designed to satisfy λ _B ≒ λ _W.
In particular, it is necessary to design the material. More specifically, λ _B is determined by the following equation (8) according to the occupancy ratio and thermal conductivity of each component of sensor B.

λ _B =a _ios λ _ios +a _she λ _she +aTλT
+aTλT/100...(8) However, a is the cross-sectional area occupation ratio (%) of each component,
λ is the thermal conductivity of each component (kcal/m・hr・℃)
, and the meanings of the subscripts are as follows.

ins; Insulating material (including the insulating material inside the sheathed thermocouple) she; Sheath tube (sheath tube and outer shell of the sheathed thermocouple) T; Side metal wire of the sheathed thermocouple T; 〃 Side metal wire Therefore, λ _W ≒a _ios λ _ios +a _she λ _she +aTλT
+aTλT/100……(9) λ _ios , λ _she , λT,
It is sufficient to select λT. However, in practice, λT,
The materials used for λT are determined based on thermocouple performance, and the materials used for λ _she are determined based on corrosion resistance as described above. Therefore, the insulating material constituting the sensor B can be selected by varying λ _ios and selecting one that satisfies equation (9). As a result, the influence of thermal disturbance based on the F term can be almost completely ignored, so the heat flow Q1 between adjacent temperature sensing parts,
The calculation accuracy of Q2,...Q5 is further improved, and the state of heat transfer in the wall thickness direction can be grasped more accurately.

In the above embodiment, a sensor having six temperature-sensing parts was used, but it is sufficient to have at least three or more temperature-sensing parts. This means that when there are two temperature sensing parts, the heat flow in the wall thickness direction has one heat flow calculation value based on the temperature difference ΔT between a certain short distance in the wall thickness direction or between two distant points on the inside of the furnace and the shell side. This is because the distribution has to be estimated, which has the same drawbacks as conventional heat flow meters.On the other hand, if the number of temperature sensing parts is 3 or more, a heat flow calculation value of at least 2 or more can be obtained, and the heat flow in the wall thickness direction The heat flow distribution is actually measured as a straight line or curve,
This is because sufficient accuracy effects can be enjoyed. The number of temperature-sensing parts (3 or more) to be set can be appropriately determined by considering the thickness of the fireproof wall, the heat load in the furnace, etc.

Further, in the above embodiment, the sensor B is buried in a direction substantially perpendicular to the fireproof wall W, but
Of course, there is no limit to the direction in which it is buried, and furthermore, the outer sheath tube is not absolutely required.

In addition, although the above explanation focused on the fireproof wall of the blast furnace, it goes without saying that it is not limited to this.
In short, the present invention can be effectively applied to all furnaces, devices, etc. where the inside cannot be seen directly and the internal thermal load needs to be known.

Since the present invention is configured as described above, the fireproof wall,
In particular, it has become possible to directly, accurately and continuously measure the heat flow distribution in a specific direction within the walls of blast furnaces, that is, the state of heat transfer. Therefore, based on the measurement results, it is possible to more accurately and quickly understand the state of wear on the inner surface of the refractory wall and the situation inside the furnace over a long period of time after blast furnace firing, and this will greatly contribute to stabilizing blast furnace operations. Summer.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the principle of the buried heat flow measurement method, Fig. 2 is a schematic explanatory diagram when the method of the present invention is applied to a blast furnace refractory wall, and Fig. 3 is a temperature detection diagram used to implement the method of the present invention. Partially cutaway perspective view of the sensor,
Figure 4 is a developed cross-sectional view equivalent to Figure 3, Figure 5 is a partially cutaway diagram of another temperature detection sensor, Figure 6 is a cross-sectional view taken along the - line in Figure 5, and Figure 7 is a diagram of heat disturbance. It is a state explanatory diagram. A...Heat flow meter, B, B'...Temperature detection sensor, W
...Fireproof wall, 1... Mantle sheath tube, 2a... Sheath type thermocouple, 3, 10... Insulating material, P1 to P6... Temperature sensing part.

Claims (1)

[Claims] 1 Having three or more temperature sensing parts in a specific direction of the fireproof wall,
In addition, a temperature detection sensor having approximately the same thermal conductivity as the fireproof wall material is embedded, and the heat flux between adjacent temperature sensing parts is calculated based on the temperature measurement results detected at each temperature sensing part, and the wall thickness is calculated. A method for measuring heat flux within a fireproof wall, characterized by measuring the state of heat transfer in a direction.