JPH0442445B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for controlling the temperature of hot metal in a blast furnace, and more specifically, the present invention relates to a method for controlling the temperature of hot metal in a blast furnace, and in particular, the temperature of hot metal in a blast furnace is controlled in relation to the measured temperature and theoretical temperature of coke near the blast furnace tuyere. This invention relates to a method of controlling with high precision.

[Prior Art] A recent challenge in blast furnace operation is the stable supply of large amounts of hot metal at low cost.There has been a strong push toward higher efficiency in blast furnace operation, and there has been significant progress in blast furnace operation technology. There were many unknowns about the phenomena inside the blast furnace, and it was considered to be a so-called black box, but as blast furnace dismantling surveys were carried out one after another, the phenomena inside the blast furnace were gradually becoming clearer. However, how to control blast furnace operations while understanding the various phenomena inside the blast furnace is one of the major concerns in the steel industry today, and the results of research at each steelworks are enormous. .

In terms of direction, these studies focus on (1) technology to accurately grasp the current state of operation, and (2) control of various operational factors based on the above knowledge to obtain optimal operating conditions. It can be broadly divided into two types of technology. The research results mentioned above have mainly blossomed in the area of (2), but in the area of (1), there is still a trial-and-error aspect, and the application of all known measurement techniques to date has not been considered. ing. In other words, since there is a considerable amount of technological accumulation in (2), operational control, if it were possible to grasp the current situation with high precision in (1), there would be a considerable degree of freedom. Depending on the degree of expansion, the detection results can be used for (2). From this point of view, in order to establish technology in the direction of (1), which can be called a prerequisite, or to grasp the current situation with high precision, it is important to know how to obtain what information from what phenomena with high precision. This is the current issue.

[Problems to be Solved by the Invention] Various methods for controlling blast furnace operating conditions have been disclosed to date, but some problems remain in all of the methods. As a prior art, for example, Japanese Patent Publication No. 60-18721 discloses a method of predicting the hot metal temperature using a mathematical model to grasp the current status of the blast furnace and controlling the blast furnace operating conditions. It cannot be denied that there are limitations to estimation accuracy and low prediction accuracy because the causes of fluctuations have not yet been fully clarified. As another prior art, for example, Japanese Patent Application Laid-Open No. 60-39107 discloses a method of controlling the temperature of hot metal in a blast furnace by measuring the temperature of the charge at the abdomen of each blast furnace. Another problem is that measurement means such as insertion devices are expensive, it is difficult to measure continuously, and there are restrictions on the frequency of measurement, making it impossible to grasp the current situation inside the blast furnace, which changes from moment to moment. Problems are recognized.

If you want to know the current state of blast furnace operation, you have traditionally focused on ore-related matters, but recently coke has also become a focus of attention. The movement is becoming more active. Among these, the behavior of coke is attracting particular attention. For example, by applying high-speed cameras, high-speed TVs, or luminance meters to the tuyere peep holes, the coke supply mechanism to the raceway, and even the raceway. The combustion situation within the way is investigated and the results of the investigation are used as control factors and fed back. However, while the technology for utilizing survey results has been highly developed as mentioned above, the current state is that the technology for obtaining information has not yet reached a fully satisfactory state.

In view of the above-mentioned current situation, the inventors of the present invention set it as their immediate task to establish a technology that can accurately grasp the temperature level of coke in the dripping zone, and further apply this technology as a control factor to the control of blast furnaces. Through intensive research, we have completed the present invention.

[Means for Solving the Problems] The present invention measures the radiant energy in front of the tuyere by spectroscopy, calculates the actual temperature of the coke falling in front of the tuyere using a two-color temperature calculation method, and measures the temperature of coke falling in front of the tuyere. The theoretical temperature of coke in the raceway is calculated based on the gas temperature in the raceway obtained from the balance calculation, and then the coke temperature transition in the dripping zone in the blast furnace is derived using the difference between the actual measured temperature and the theoretical temperature, and the coke temperature is calculated. The gist of this method is to control the hot metal temperature by adjusting operating conditions so that the transition is maintained within a predetermined range.

[Operation] Although the present invention is configured as described above, it is first necessary to actually measure the temperature of the coke falling into the lakeway. This can be easily realized by the two-color temperature calculation method (Japanese Patent Application No. 107116/1982) which the present applicant has already filed. The principle and outline of the method are as follows.

There are no restrictions on the means for actually measuring the temperature of the raceway at the blast furnace tuyere, but an example of a spectroscopic analyzer is constructed as shown in FIG. For example, when measuring temperature, the spectrometer 1
The light inside the tuyere 3 obtained by the half mirror 2, condensing lens (not shown), etc. is transmitted through an optical fiber 4, etc., and some characteristic wavelengths are obtained by spectroscopic analysis. Two color temperature calculations are performed using the two. FIG. 3 shows an example of the spectral distribution obtained by the spectroscopic analyzer 1. For example, at point A (wavelength λ ₁ =
550 nm) and point B (wavelength λ ₂ =660 nm). In other words, gas, flame light, and radiation from solid coke are measured in the spectrum, but in the wavelength range of 400 to 800 nm, the energy radiated from solid coke is dominant, so the measured temperature is due to the raceway. This is representative of the decreasing coke temperature. If correction is made in advance using a blackbody furnace, a more accurate temperature can be obtained.

In the above manner, the temperature T _O of the coke falling in front of the tuyere is determined, and the coke is heated by the boiling gas generated in the raceway near the raceway and during turning. Then, the gas temperature in the raceway (theoretical combustion temperature before the tuyere) is determined from the heat/mass balance calculation in the raceway, and based on this gas temperature, the theoretical temperature of coke in the raceway T _t (75% of the gas temperature) is determined. %) can be calculated.

The combustion reaction of coke in front of the tuyere in the furnace proceeds as follows. In other words, the amount of coke in the furnace is approximately 1000 in front of the tuyere.
It is combusted by hot air (containing moisture) at ℃ and becomes a mixed gas consisting of high-temperature reducing CO, H ₂ , N ₂ , etc. The coke packed bed in front of the tuyere becomes sparse due to the strong flow of hot air, forming a combustion space. The reaction between oxygen in hot air and coke proceeds as shown in equations (1) to (3) below.

C+O ₂ →CO ₂ +97.6 [Kcal/mol] …(1) C+CO ₂ →2CO−38.8 [Kcal/mol] …(2) C+H ₂ O→CO+H ₂ −28.8 [Kcal/mol] …(3) Feather As the distance from the tip of the mouth increases, the above reactions proceed in the following order. First, O ₂ in the hot air reacts with coke to generate CO ₂ as shown in equation (1). The reaction according to equation (1) has a large calorific value, and as the reaction progresses, the gas temperature increases. As a result, the oxygen concentration decreases, and then the reactions of equations (2) and (3) proceed, and at the end of the space, tuyere gas consisting of CO, H ₂ and N ₂ is formed, and combustion is completed.

In consideration of the above reactions, the gas temperature at the raceway is calculated by applying the calorific value of coke, sensible heat of hot air, sensible heat of moisture in air blowing, etc., and their amounts as elements of heat-mass balance calculation. be able to.

In order to control the temperature of hot metal in the blast furnace, it is necessary to understand the coke temperature transition in the dripping zone in the blast furnace. The coke temperature transition can be determined from the difference ΔT between the actual coke temperature T ₀ measured by spectroscopic analysis and the theoretical coke temperature T _t . Therefore, the temperature of hot metal in the blast furnace can be controlled with high precision by adjusting operating conditions such as air temperature and air humidity so that the coke temperature transition is maintained within a certain range.

[Example] Next, typical examples of the present invention will be shown to further clarify the structure.

FIGS. 1 to 4 are graphs showing temporal changes in the coke temperature T ₀ before the tuyere, the hot metal temperature, the blast temperature, and the temperature difference ΔT. In addition, Fig. 1 1 and 1
In FIG. 4, measurements were taken at three tuyeres.

Comparing Figures 1 and 4, it can be seen that although the coke temperature T ₀ before the tuyere gradually changes, the temperature difference ΔT fluctuates greatly. This is the theoretically required coke temperature in the raceway.
This suggests that T _t is changing from moment to moment. In the present invention, the coke temperature changes in this way.
This method takes into account T _t and corrects this by adjusting the coke temperature before the tuyere T ₀ to accurately grasp the optimal operating conditions, which allows the hot metal temperature to be controlled with high precision. .

Further, FIG. 1 and 2 illustrate the temporal change in hot metal temperature, and the hot metal temperature deviates from the control value (predetermined standard) of 1500 to 1520°C, which is insufficient for blast furnace operation. This is because the blast temperature was raised at the P ₀ point, where the hot metal temperature began to fall, and the blast temperature was decreased at the Q ₀ point, where the hot metal temperature rose [see Figure 1, 3]. Comparative consideration of FIG. 1 2 and FIG. 1 4 shows that the transition of the temperature difference ΔT precedes the transition of the hot metal temperature by 2 to 3 hours. Therefore, judging from the trend of the temperature difference ΔT, the air blowing temperature is increased at _one point P when the temperature difference ΔT starts to decrease, and at the point when the temperature difference ΔT reaches an extreme value and starts to decrease again (point Q ₁ ). If you reduce the temperature of the air,
Significant fluctuations in hot metal temperature can be reliably avoided. Of course, the control factor is not limited to the above-mentioned air blowing temperature.

By managing the temperature difference ΔT in the manner described above, it becomes possible to control the hot metal temperature in the blast furnace with high precision.

[Effects of the Invention] As described above, according to the present invention, by employing the configuration described above, it becomes possible to control the temperature of hot metal in the blast furnace. Furthermore, by performing spectroscopic analysis on all or a large number of tuyeres in a blast furnace, it becomes possible to detect fluctuations in the circumferential direction inside the furnace.
As a result, overall operational management of the blast furnace can be achieved.

[Brief explanation of drawings]

Fig. 1 is a graph showing the temporal change in coke temperature before the tuyere, Fig. 1 is a graph showing the temporal change in hot metal temperature, Fig. 1 is a graph showing the temporal change in blast temperature, 4 is a graph showing the temporal change of the temperature difference ΔT, FIG. 2 is a block diagram showing the configuration of the spectroscopic analyzer 1, and FIG. 3 is a graph showing an example of the spectral distribution by the spectroscopic analyzer 1. 1... Spectroscopic analyzer, 2... Half mirror, 3...
...tuyere, 4...optical fiber.

Claims (1)

[Claims] 1. The radiant energy in front of the tuyere is measured by spectroscopy, and the measured temperature of the coke falling in front of the tuyere is determined using the two-color temperature calculation method, and on the other hand, the measured temperature of the coke falling in front of the tuyere is determined based on the gas temperature in the raceway determined from heat and mass balance calculations. The theoretical temperature of coke in the raceway is calculated, and then the difference between the measured temperature and the theoretical temperature is used to derive the coke temperature transition in the dripping zone in the blast furnace, so that the coke temperature transition is maintained within a predetermined range. A method for controlling hot metal temperature in a blast furnace, characterized by controlling hot metal temperature by adjusting operating conditions.