JP4380331B2 - How to protect the iron core of a rotary furnace - Google Patents

Description

  The present invention relates to a method for protecting an iron skin of a rotary furnace and further a refractory.

  A rotary kiln represented by a rotary kiln is a furnace that heats and melts an object to be heated by burning fuel while rotating the furnace body mainly for the purpose of improving thermal efficiency and preventing refractory melts.

  Since the temperature of each part in the furnace during operation of such a rotary furnace is not uniform, the progress rate of wear of the refractory varies among the parts in the furnace. The iron skin near the refractory that has been worn out more than the other refractories has a higher temperature than the other portions, and eventually reaches a melting point. In order to prevent this, refractories are repaired at predetermined intervals, which leads to a decrease in the operating rate of the rotary furnace and an increase in repair costs, and the operation efficiency of the rotary furnace has been reduced. . For this reason, there is a strong demand for a technique capable of continuously operating for as long a period as possible while suppressing the temperature rise of the iron skin and the progress of wear of the refractory.

Patent Document 1 discloses an invention that protects a refractory of a rotary furnace by supplying cooling water to a water cooling jacket provided around the furnace body to uniformly cool the entire furnace body. .
Patent Document 2 and Patent Document 3 disclose an invention in which an auxiliary burner is provided in the vicinity of the outlet of the furnace body of the rotary furnace and combustion is also performed in the vicinity of the outlet of the furnace body, thereby preventing slag adhesion near the outlet. It is disclosed.

Japanese Patent Laid-Open No. 2003-4213 JP 2001-280850 A JP 2000-285850 A

  In the invention disclosed in Patent Document 1, since the temperature of the iron skin is not measured, it is impossible to find local wear of the refractory, and the protection measures for the iron skin should be performed at an accurate timing. I can't. Even if the temperature of the iron skin is measured, since the iron skin is always water-cooled, it is difficult to detect and identify the position where local wear has occurred. Furthermore, in this invention, since the whole furnace body is cooled uniformly regardless of the degree of wear of the refractory, the refractory in the non-wear portion is excessively cooled. For this reason, there is a possibility that the refractory cooled excessively may be thermally contracted and damage the refractory in the non-wearing part. For this reason, even with the invention disclosed in Patent Document 1, the life of the refractory is only about one month at most, and the wear of the refractory in the rotary furnace cannot be effectively suppressed.

In addition, even with the invention disclosed in Patent Document 2 or Patent Document 3, the wear of the refractory cannot be effectively suppressed. Hereinafter, this reason will be described with reference to the accompanying drawings.
FIG. 1 is an explanatory view schematically showing an example of a cross section in the longitudinal direction of a furnace body 2 of a rotary furnace 1 represented by a rotary kiln. FIG. It is a graph which shows an example of temperature distribution. Furthermore, FIG. 3 is an explanatory view schematically showing an example of a cross section in the longitudinal direction when the invention disclosed in Patent Document 2 or Patent Document 3 is applied to the furnace body 2 of the rotary furnace 1 typified by a rotary kiln. It is.

  As shown in FIGS. 1 and 2, since the combustion burner 3 is installed near the entrance of the furnace body 2 of the rotary furnace 1, the tip of the flame 4 formed by the combustion burner 3 (A in FIGS. 1 and 2). Near the point, a first temperature peak is formed in the longitudinal direction. On the other hand, since the flame 4 formed by the combustion burner 3 is difficult to reach near the outlet of the furnace body 2, the slag 5 tends to adhere and accumulate, and the molten reduced iron stagnates near the point B in FIGS. As a result, the hot metal pool 6 is formed. For this reason, the temperature also increases near the point B, and a second temperature peak is formed in the longitudinal direction.

  According to the invention disclosed in Patent Document 2 or Patent Document 3, the hot metal pool 6 formed in the vicinity of the point B, which is the tip of the flame 8 formed by the auxiliary burner 7 provided in front of the outlet of the furnace body 2. However, the second temperature peak is generated near the tip of the flame 8 of the auxiliary burner 7.

  Thus, even with the invention disclosed in Patent Document 2 or Patent Document 3, the temperature distribution of the furnace body 2 of the rotary furnace 1 is two in the overall length in the longitudinal direction of the furnace body 2 due to the positional relationship with the combustion burner 3. A peak is formed and does not become uniform. For this reason, it was not possible to effectively suppress the wear of the refractory and prevent the iron skin from being melted due to this wear.

  The object of the present invention is to effectively suppress the wear of the refractory in the rotary furnace, and thereby maintenance can be carried out by greatly extending the repair period, which was conventionally about 1 month, to about 6 months, for example. An object of the present invention is to provide a method for protecting the iron core of a rotary furnace capable of reducing costs and improving the operating rate.

In the present invention, the temperature of the surface of the iron shell constituting the furnace body of the rotary furnace is measured for each part in the furnace body circumferential direction, and the measured temperature deviates from a predetermined management temperature range. Then, when this part passes through the cooling water supply part that supplies the cooling water to the outer surface of the iron skin, by supplying the desired amount of cooling water, the temperature of the deviated part is set within the management temperature range and is managed. When the part in the circumferential direction of the furnace body that deviates from the temperature range passes through the lower part of the furnace body, the rotational speed of the furnace body is set to (1/20) rpm or more (1/10) rpm or less, and the management temperature range is set to When the deviated portion in the circumferential direction of the furnace body passes through the lower part of the furnace body, the rotation speed of the furnace body is set to exceed (1/10) rpm .

Further, the present invention measures the temperature of the surface of the iron skin constituting the furnace body of the rotary furnace for each part in the furnace body longitudinal direction and each part in the furnace body circumferential direction, and measures the furnace body longitudinal direction. The amount of cooling water supplied to the outer surface of the iron shell from each of the plurality of cooling water supply units arranged in the longitudinal direction of the furnace body with respect to the portion where the temperature deviated from the predetermined management temperature range is set to a plurality of cooling water. When the part where the temperature measured in the circumferential direction of the furnace body deviates from the predetermined management temperature range passes through the cooling water supply part that supplies the cooling water to the outer surface of the iron skin while individually adjusting each supply part By supplying a desired amount of cooling water, the temperature of the deviated part is set within the control temperature range, and when the part in the furnace circumferential direction deviating from the control temperature range passes through the lower part of the furnace body , , The rotational speed of the furnace body is (1/20) rpm or more ( / 10) and rpm or less, the rotation site of deviates from the control temperature range furnace body circumferentially as it passes through the furnace bottom, which is characterized in that the rotational speed of the furnace body and (1/10) rpm than This is a method for protecting the iron skin of the furnace.

In these methods for protecting the iron core of a rotary furnace according to the present invention, it is desirable to correct the supply amount of the cooling water from the cooling water supply unit based on the actual temperature of the iron skin.
In these methods for protecting the iron skin of a rotary furnace according to the present invention, the supply of the cooling water is stopped for a certain time after the cooling water is supplied, and then the temperature of the iron skin is measured, and this temperature rises again. It is desirable to restart the supply of cooling water when the temperature deviates from the temperature control range.

  In these methods for protecting the iron core of a rotary furnace according to the present invention, the supply of cooling water from the cooling water supply unit to the part where the temperature measured in the circumferential direction of the furnace body deviates from the predetermined management temperature range is It is desirable to perform this by tracking the temperature and position information of the part between the temperature measurement point and the cooling water supply unit.

In these methods of protecting the iron core of a rotary furnace according to the present invention, the supply of cooling water to the part that deviates from the control temperature range or the adjustment of the rotation speed of the furnace body is performed between the temperature measurement point and the cooling water supply unit. Or, it is exemplified that tracking is performed by tracking the temperature and position information of a part that deviates from the management temperature range between the temperature measurement point and the lower part of the furnace body. In these methods for protecting the iron core of a rotary furnace according to the present invention, the rotational speed of the furnace body is reduced to 1/20 at a time other than when the circumferential part of the furnace body that deviates from the control temperature range passes through the lower part of the furnace body. ) Set the rotation speed of the furnace body to more than (1/10) rpm when the portion in the circumferential direction of the furnace body that deviates from the control temperature range passes through the lower part of the furnace body. Thus, the passage time of the high temperature portion of the refractory can be shortened, and thus the refractory can be protected.

In these methods for protecting the iron core of a rotary furnace according to the present invention, it is desirable for the management temperature range to be 400 ° C. or less in order to protect the refractory.
In these methods for protecting the iron core of a rotary furnace according to the present invention, when the thickness of the refractory of the rotary furnace is 200 to 400 mm, the management temperature is exemplified to be 200 ° C. or higher.

  In these methods for protecting the iron core of a rotary furnace according to the present invention, it is desirable that the temperature measurement of the surface of the iron skin is performed at a site on the surface of the iron skin where the cooling water is not directly applied.

  With the method of protecting a rotary furnace core according to the present invention, it is possible to effectively suppress the wear of the refractory of the rotary furnace, thereby reducing the repair cycle, which was conventionally about 1 month, to about 6 months, for example. As a result, the maintenance cost can be reduced and the operating rate can be improved.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the best mode for carrying out a method for protecting an iron skin of a rotary furnace according to the present invention will be described in detail with reference to the accompanying drawings.
In the present embodiment, briefly described, (1) the temperature of the surface of the iron skin constituting the furnace body of the rotary furnace is measured for each part in the furnace body longitudinal direction and for each part in the furnace body circumferential direction. And (2) an iron skin from each of a plurality of cooling water supply units arranged in the furnace body longitudinal direction with respect to a part where the temperature measured in the furnace body longitudinal direction deviates from a predetermined management temperature range. The amount of cooling water supplied to the outer surface of each of the plurality of cooling water supply units is individually adjusted for each of the plurality of cooling water supply units, and the portion where the temperature measured in the circumferential direction of the furnace body deviates from the predetermined management temperature range is the iron skin. By passing through a cooling water supply part that supplies cooling water to the outer surface of the second step of bringing the temperature of the part deviated by supplying a desired amount of cooling water within the control temperature range, Protect the iron bar of the rotary furnace. Therefore, the first step and the second step will be sequentially described.

(1) 1st process (measurement of the temperature of the surface of an iron skin for every site | part of a furnace body longitudinal direction and a furnace body circumferential direction)
In the present embodiment, as the first step, the temperature of the surface of the iron skin constituting the furnace body of the rotary furnace is measured for each part in the furnace body longitudinal direction and for each part in the furnace body circumferential direction. Thereby, the wear part in which wear progressed among iron skin is specified.

  In order to make the temperature distribution in the longitudinal direction of the furnace body 2 as uniform as possible, taking as an example the invention disclosed by Patent Document 3 in which the auxiliary burner 7 is provided near the outlet of the furnace body 2 described with reference to FIG. The means will be described.

FIG. 4 is an explanatory view showing an example of the furnace body circumferential section at an arbitrary position in the longitudinal direction of the rotary furnace 1, and FIG. 5 is a graph showing an example of the temperature distribution of the furnace body circumferential section.
As shown in FIGS. 4 and 5, the inner wall temperature of the refractory constituting the rotary furnace 1 is constant due to the influence of the adhesion state of the product generated from the molten steel even at the same position in the longitudinal direction of the furnace body. However, the product such as slag adhering to the inner wall of the furnace is partially dropped by the action of the rotation of the furnace body 2 and the like. -C point, C point-D point, D point-E point, E point-F point) locally and inevitably occur.

  Further, FIG. 6 is an explanatory view schematically showing a cross-sectional structure of the refractory 8 and the iron shell 9 constituting the furnace body 2 of the rotary furnace 1. The refractory 8 is formed with a uniform thickness t in the circumferential direction in order to have a certain heat insulation performance.

  However, due to the temperature distribution on the inner wall side of the refractory 8, there is also a temperature distribution on the surface of the iron skin 9. In addition, since the wear of the refractory 8 tends to progress locally centering around a portion where the amount of deposits generated is low and the inner wall temperature of the refractory 8 becomes high, the thickness of the refractory 8 is locally localized around this portion. The heat insulation performance is reduced.

  Even if the temperature rise of the iron skin 9 is detected by measuring the surface temperature of the iron skin 9 and left as it is without taking any countermeasures, the wear of the refractory 8 will cause the iron The temperature continues to rise. In the conventional operation of the rotary furnace, since even the temperature measurement of the iron skin 9 was not performed, the overheated portion of the iron skin 9 could not be detected, and the iron skin 9 could even be melted.

  Therefore, in the present embodiment, the surface temperature of the iron skin 9 is measured by utilizing the fact that the iron skin 9 where the wear of the refractory 8 is remarkable is higher than that of the iron skin 9 with little wear. To indirectly detect and identify the degree of wear of the refractory 8. That is, the worn part of the refractory 8 of the furnace body 2 is detected and specified by measuring the temperature of the iron shell 9 of the rotary furnace 1.

Next, a means for monitoring the temperature of the iron skin 9 of the rotary furnace 1 will be described.
FIG. 7 is a graph showing an example of the relationship between the remaining thickness of the refractory 8 and the temperature of the iron shell 9 when the furnace temperature of the rotary furnace 1 during melting operation is 1280 ° C.

  As shown in the graph of FIG. 7, the wear of the refractory 8 is characterized in that the relationship between the decrease in the thickness of the refractory 8 and the increase in the temperature of the iron shell 9 changes remarkably at a certain level. is there. From this characteristic, the temperature limit value of the iron skin 9 is considered to be around 400 ° C. in the example shown in the graph of FIG. 7, and when the wear level of the refractory 8 progresses beyond this temperature limit value, The temperature rises rapidly.

  Therefore, the upper limit control value of the temperature of the iron skin 9 of the furnace body 2 is set as 400 ° C., and the cooling water supply for supplying the cooling water 11 to the furnace body 2 when the temperature of the iron skin 9 exceeds 400 ° C. As shown in FIG. 8 showing the configuration of the apparatus 10, the refractory 8 is protected from the heat in the furnace by supplying the cooling water 11 to the iron skin 9 of the furnace body 2 by spraying from the outside. Even if some wear parts occur, the temperature of the iron skin 9 and the wear of the refractory 8 can be suppressed.

However, if the cooling water 11 is simply sprayed and supplied from the cooling water supply device 10 to the iron shell 9 of the furnace body 2, there are problems (i) to (iv) listed below.
(I) Since the cooling water 11 is supplied in a constant amount regardless of the degree to which the iron skin 9 is overheated, the temperature of the iron skin 9 is excessively cooled to the non-wearing portion of the refractory, There is a risk of causing heat shrinkage of the refractory and causing damage such as cracks.

(Ii) When the cooling water 11 is constantly supplied, the temperature of the iron skin 9 in the vicinity of the refractory worn out decreases to the same level as the temperature of the iron skin in the vicinity of the non-wearing portion. This makes it difficult to detect and identify the refractory wear part.

(Iii) When the temperature of the iron skin 9 is measured with a radiation thermometer, it is easy to measure the temperature distribution of the entire iron skin 9, but when cooling water is applied to the measurement point, the measurement error of the temperature of the iron skin 9 increases. .
(Iv) FIG. 9 is a graph showing a temperature change cycle in the circumferential direction of the iron skin 9. As shown in the graph in the figure, molten metal accumulates near the bottom of the rotary furnace 1, and the temperature of the iron core 9 rises most at the timing of passing the lower part in the circumferential direction even at the same part of the surface of the iron core 9. Therefore, it is necessary to strengthen the protection of the refractory worn part in the lower part of the furnace body 2.

  Therefore, in the present embodiment, in order to prevent the occurrence of these problems (i) to (iv), the second step of adjusting the cooling water supply amount to the iron skin 9 is started as follows. The means (2) to (5) are adopted.

(2) Second step (adjustment of the amount of cooling water supplied to the iron skin)
In the present embodiment, the worn portion is partially determined according to the degree of wear of the worn portion of the refractory 8 of the furnace body 2 detected and specified by measuring the temperature of the iron shell 9 of the rotary furnace 1. By appropriately cooling, the wear of the refractory 8 of the rotary furnace 1, and further, the melting loss of the iron skin 9 due to the wear of the refractory 8 is effectively suppressed to extend the life.

  Specifically, in this embodiment, in order to detect local wear of the refractory 8, as shown in FIGS. 11 and 12 to be described later, around the furnace body 2 of the rotary furnace 1 in the longitudinal direction of the furnace body. A radiation thermometer 12 for measuring the temperature distribution is installed. The temperature distribution in the circumferential direction of the furnace body 2 is measured by the radiation thermometer 12 and the rotation of the furnace body 2. And when the temperature of the iron skin 9 measured with the radiation thermometer 12 exceeds 400 degreeC, the cooling water supply part corresponding to the longitudinal direction position of the cooling water 14 of the quantity according to the part for the temperature rise exceeded 13 individually supplied. As a result, the temperature measured in the longitudinal direction of the furnace body is supplied to the outer surface of the iron skin 9 from each of the plurality of cooling water supply units 13 arranged in the longitudinal direction of the furnace body with respect to the part where the temperature deviates from the predetermined management temperature range. The amount of the cooling water 14 is adjusted individually for each of the plurality of cooling water supply units 13.

  On the other hand, with respect to the circumferential direction of the furnace body, it is considered most appropriate to arrange a plurality of cooling water supply units 13 in a circumferential manner as in the longitudinal direction of the furnace body. Emphasizing, one unit is installed above the furnace body of the rotary furnace 1 in the circumferential direction of the furnace body. Then, by tracking the temperature data measured by the radiation thermometer 12 in the circumferential direction in synchronization with the rotation, the portion where the temperature measured in the circumferential direction of the furnace body deviates from the predetermined management temperature range is iron. When passing the cooling water supply part 13 which supplies the cooling water 14 to the outer surface of the skin 9, a desired amount of the cooling water 14 corresponding to the temperature rise of the temperature data is supplied. As a result, a desired amount of cooling water can be supplied only at the timing when the superheated part passes near the cooling water supply part 13.

  In this embodiment, since the amount of cooling water supplied to the iron skin 9 is adjusted in this way, an appropriate amount of cooling water 14 can be supplied according to the degree of overheating of the iron skin 9, and the temperature of the iron skin 9 can be supplied. However, the non-wearing portion of the refractory having a relatively low temperature is not excessively cooled, and there is no possibility of causing damage to the refractory. In the present embodiment, the above-described problem 1 is solved in this way.

  Furthermore, in this Embodiment, the 3rd process-the 5th process demonstrated below are also performed with a 1st process and a 2nd process, and the protection of the iron skin 9 is performed completely. Therefore, the third to fifth steps will be sequentially described.

(3) Third step (stopping the cooling water supply for a predetermined time after cooling or reducing the supply amount)
FIG. 10 is a graph illustrating an example of the cooling water supply method according to the present embodiment over time.

  As shown in the graph of FIG. 10, in the present embodiment, in the second step, the furnace body longitudinal direction and / or the furnace body with respect to only the superheated portion of the furnace body 2 based on the measurement result of the temperature of the iron shell 9 by the second step. After the cooling water 14 is partially supplied in the circumferential direction, the supply of the cooling water 14 is stopped for a predetermined time, or the supply amount of the cooling water 14 is decreased, so that the temperature rise of the iron skin 9 is reduced. Monitor and re-detect temperature rise.

  That is, when the cooling water 14 is continuously supplied to the superheated portion of the iron skin 9 by the method of the present embodiment, the temperature of the iron skin 9 gradually decreases and finally reaches 400 ° C., which is the upper limit management temperature of the iron skin 9. The temperature distribution on the surface of the iron skin 9 becomes substantially uniform regardless of the degree of wear of the refractory. However, if this state continues, there are problems such that it becomes impossible to detect the worn portion of the refractory material due to the temperature level, and the temperature of the entire furnace body decreases.

  Therefore, in the present embodiment, the cooling water supply amount is changed according to the degree of wear of the refractory 8. For example, when the supply of the cooling water 14 is stopped, the lower limit management value of the temperature of the iron shell 9 is set as a predetermined temperature (for example, 200 ° C.), and if the value is lower than this value, the wear level of the refractory 8 is small. Alternatively, the refractory 8 is appropriately cooled while always grasping the worn part from the tendency of temperature rise by adjusting the reduction of the supply of the cooling water 14 or stopping it, assuming that there is no wear. Adjust as follows.

  In the present embodiment, when the thickness of the refractory 8 is normal 200 mm or more and 400 mm or less, the surface temperature of the iron skin 9 is a predetermined temperature (200 ° C. in FIG. 7) in the melting operation in which the furnace temperature is around 1300 ° C. Since it can be the following, the lower limit control value of the temperature of the iron skin 9 was set to 200 ° C.

In the present embodiment, in the second step, the supply of the cooling water 14 is temporarily stopped at the timing when the portion where the thickness of the refractory 8 is normal passes through the cooling water supply unit. Overheating of the refractory 8 is suppressed, but it is determined that the thickness of the refractory 8 is normal in the rotary furnace 1 in the normal range (200 mm or more and 400 mm or less) at a furnace temperature of 1300 ° C. Then, since the temperature of the iron skin 9 becomes around 200 ° C., it can be determined based on the measurement result of the temperature of the iron skin 9.
Thereby, since the cooling water 14 is not always supplied, a refractory wear part can be detected. For this reason, the above-described problem 2 can be solved.

(4) Fourth step (iron skin temperature measurement and tracking control)
FIG. 11 is a schematic explanatory view showing an example of the iron skin temperature measurement and tracking control method in the present embodiment. As shown in FIG. 11, the radiation thermometer 12 for measuring the temperature is arranged on the side opposite to the cooling water supply unit 13 through the rotating furnace body 2 and the data (temperature) measured at the portion where the cooling water 14 is not applied. (Circumferential position information) is tracked to the cooling water supply unit 13 in synchronization with the rotation, and the cooling water supply unit 13 supplies an appropriate amount of the cooling water 14 according to the degree of wear.

  In this embodiment, the temperature measurement of the iron skin was performed using a radiation thermometer as a simple method. However, when the supplied cooling water enters the measurement point, the temperature of the iron skin cannot be measured accurately. Therefore, the part where the cooling water is not applied on the surface of the iron skin was arranged as a measurement point of the radiation thermometer.

  Thereby, the measurement error of the temperature of the iron skin 9 caused by the cooling water being applied to the measurement point does not occur. Thereby, the above-described problem 3 can be solved.

(5) Fifth step (adjustment of the rotational speed of the furnace body 2 at the timing of passing through the lower part of the furnace body)
FIG. 12 is a schematic explanatory view showing an example of a protection operation when passing through the lower part of the furnace body in the present embodiment. As shown in FIG. 12, using the tracking data obtained by tracking the data (temperature / circumferential position information) measured at a portion not exposed to the cooling water 14 to the cooling water supply unit 13 in synchronism with the rotation, the wear part becomes the furnace. By adjusting the rotational speed of the furnace body 2 at the timing of passing through the lower part of the body, the time during which the refractory worn part is exposed to the high temperature part can be relatively shortened, thereby suppressing local progress of wear. .

  That is, the bottom of the rotary furnace 1 where molten metal accumulates is a part that is particularly hot in the circumferential direction of the furnace body. Therefore, at the timing of passing through this position, the inner wall temperature of the refractory 8 particularly increases as compared with the timing of passing through other parts, and the cooling water 14 is supplied from the upper part of the furnace body. There is a problem that the cooling effect decreases.

  Therefore, in the present embodiment, when the superheated portion of the iron skin 9 where the refractory 8 is worn is within a range of ± 30 ° with respect to the furnace body vertical line that may be directly exposed to the molten metal. To adjust the rotary furnace 1 that normally rotates in a 20-minute cycle to rotate in a 10-minute cycle or more, the time for the worn part to pass through this high temperature range is reduced to 50% or less of the non-weared part. This suppresses the progress of local wear.

Thereby, protection of the refractory worn part in the lower part of the furnace body 2 can be strengthened, and the above-described problem 4 can be solved.
Thus, according to this Embodiment, the temperature of the site | part which deviated can be made into a management temperature range by performing the process 3-the process 5 through the process 1 and the process 2. For this reason, the wear of the refractory of the rotary furnace 1 can be effectively suppressed, and the iron skin of the rotary furnace can be protected. Thereby, it is possible to significantly reduce the maintenance cycle, which was conventionally about one month, to about six months, for example, and to reduce maintenance costs and improve the operating rate.

Furthermore, the present invention will be described with reference to examples.
In the following examples, a parallel flow rotary kiln having a total length of 14 m, a diameter of 5 m, a processing capacity of 2500 tons / month, and a rotation period of 20 minutes was used. A processing raw material is iron-making dust containing coal, waste plastic, and iron oxide. The furnace temperature of the parallel flow rotary kiln is as high as 1300 ° C. or higher, and even when there is no refractory wear (thickness 363 mm), the surface temperature of the iron skin reaches 200 ° C. or higher.

FIG. 13 is a graph showing a comparison between the conventional method in which the temperature measurement of the iron skin is not performed and the method of the present invention.
A curve A in the graph of FIG. 13 shows the temperature distribution of the iron skin when cooling is not performed, and a curve B shows the temperature distribution of the iron skin when a certain amount of cooling water is supplied in the longitudinal direction of the conventional method. Curve C shows the temperature distribution of the iron skin when the cooling water is supplied only at the point where the temperature of the iron skin is 400 ° C. or higher. Note that the temperature of the iron skin was measured from the side of the furnace body circumferential direction using a radiation thermometer.

From the curve A in the graph of FIG. 13, it can be seen that the temperature in the furnace reached a peak (around 400 ° C.) near the flame tip of the burner because the temperature inside the furnace became high.
Also, from curve B, the temperature near the flame tip of the burner is reduced to around 300 ° C, but in other parts (near the exit side and near the entrance side, etc.), it was overcooled to 150 ° C or less. I understand.

  On the other hand, from the curve C, the temperature of the iron skin is in the range of 200 to 300 ° C., the high temperature portion of the iron skin can be reliably cooled while suppressing excessive cooling, and the local temperature due to the deviation of the temperature distribution in the furnace It can be seen that it is effective against wear.

  FIG. 14 is a graph showing the temperature distribution in the furnace body circumferential direction measured from right next to the furnace body circumference. In the graph shown in FIG. 14, curve D shows the case of the conventional method in which cooling is not performed, curve E shows the case of the conventional method in which constant cooling water is supplied without performing temperature measurement, and curve F shows the iron skin. The case according to the method of the present invention in which the cooling water is supplied only at the point where the temperature is 300 ° C. or higher is shown.

Similar to Example 1, curve D has a point where the temperature of the iron skin locally exceeds 300 ° C. This is thought to be due to damage to the refractory.
Further, in the case of curve E, in order to always supply a constant amount of cooling water without distinguishing between the locally worn part and the healthy part, the overheated part of the iron skin exceeding 300 ° C. is eliminated, but the temperature of the healthy part is 200 ° C. It turns out that it cooled too much to the following.

  On the other hand, in the curve F, it can be seen that the temperature of the iron skin is in the range of 200 to 300 ° C., and the local temperature rise portion becomes inconspicuous.

  FIG. 15 shows a comparative example in which a furnace with a local wear part of a refractory is operated for 300 hours and supplying a certain amount of cooling water, Example 1 and Example 2, and Example 1 and Example 2 together. In the case where the temperature of the iron shell at a certain worn part exceeds 400 ° C, which is the upper limit control value, and when 200 ° C, which is the lower limit control value, is interrupted, It is a graph which compares and shows the ratio of the time which went out with respect to time.

  From the graph shown in FIG. 15, by controlling the temperature in the longitudinal direction of the furnace body or in the circumferential direction of the furnace body according to the present invention, the rate at which the temperature of the iron shell deviates from the upper limit value and the lower limit value of the management temperature can be suppressed. I understand.

  Furthermore, it turns out that the deviation from the upper limit value and the lower limit value of the management temperature is practically eliminated by using the temperature management in the furnace body longitudinal direction and the furnace body circumferential direction in combination.

  FIG. 16 shows a case where the cooling water amount is constant and the cooling water is supplied only to a portion exceeding the temperature control value of the iron shell (curve G), and an appropriate amount of cooling water is supplied as a variable according to the actual temperature (curve). It is a graph which compares and shows I).

  From the graph shown in FIG. 16, if an appropriate amount of cooling water is supplied as a variable according to the temperature results, the deviation of the temperature distribution on the surface of the iron skin can be reduced, and local wear of the refractory can be suppressed. I understand.

FIG. 17 is a graph showing changes in the temperature of the iron skin based on the difference in the cooling water supply pattern.
In the graph shown in FIG. 17, curve J shows the case where the temperature of the iron skin is measured while constantly supplying cooling water, and curve K shows the temperature measurement of the iron skin by stopping the supply of cooling water at regular intervals. The case where it went is shown. In addition, the result of the graph shown in FIG. 17 compares the temperature distribution of the iron skin of the same refractory wear part, and the temperature of the iron skin is measured using the radiation thermometer from the furnace body side surface.

  As shown in curve J, when the temperature of the iron skin is measured while constantly supplying cooling water, the iron temperature of the worn portion does not increase due to the continuous cooling effect, so that it is not known that the portion is a worn portion. End up.

  On the other hand, as shown by the curve K, if the cooling water supply is stopped at regular intervals, the cooling effect is temporarily lost. Therefore, accurate temperature measurement can be performed, and appropriate cooling water supply without excess or deficiency can be performed. It can be carried out.

  FIG. 18 is a graph showing the temperature measurement result of the iron shell at the timing when the refractory worn part passes through each part in the circumferential direction of the furnace body, and the curve K in FIG. 18 represents the furnace body rotational speed (1/20). The curve M shows the case where the furnace body rotation speed is adjusted from (1/20) rpm to (1/10) rpm only at the timing when the refractory wear part passes through the lower part of the furnace body. Show.

As shown in the graph of FIG. 18, at the timing of passing through the lower part of the furnace body, the iron skin temperature clearly rises (curve L), and it can be seen that the interior of the furnace is exposed to a high temperature.
On the other hand, if the furnace rotation speed is adjusted from (1/20) rpm to (1/10) rpm only at the timing when the refractory wear part passes through the lower part of the furnace body, as shown in the curve M, It can be seen that the increase in the temperature of the iron skin of the refractory wear part is mitigated and the refractory can be protected from high temperatures.

  FIG. 19 shows a case where a furnace in which a local wear part of a refractory is present is operated for 300 hours, and the temperature of the iron shell at one wear part in each example exceeds 400 ° C., which is the upper limit control value, and the lower limit. It is a graph which shows the relationship between the ratio of the time which went out with respect to the total operation time, and the refractory life about each when 200 degreeC which is a management value is interrupted.

  From the graph shown in FIG. 19, according to the present invention, the repair period of the refractory required a frequency of about one month according to the conventional method, but according to the present invention, this is extended to about six months. Became possible.

It is explanatory drawing which shows typically an example of the cross section to the longitudinal direction of the furnace body of the rotary furnace represented by the rotary kiln. It is a graph which shows an example of the temperature distribution to the longitudinal direction of the furnace body of a rotary furnace. It is explanatory drawing which shows typically an example of the cross section to a longitudinal direction at the time of applying the invention disclosed by patent document 2 or patent document 3 to the furnace body of the rotary furnace represented by the rotary kiln. It is explanatory drawing which shows an example of the furnace body circumferential direction cross section in the arbitrary positions of the longitudinal direction of a rotary furnace. It is a graph which shows an example of the temperature distribution of a furnace body circumferential direction cross section. It is explanatory drawing which shows typically the cross-sectional structure of the refractory and iron skin which comprise the furnace body of a rotary furnace. It is a graph which shows an example of the relationship between the residual thickness of a refractory, and the temperature of an iron shell in case the furnace temperature of the rotary furnace in melting operation is 1280 degreeC. It is explanatory drawing which shows the structure of the cooling water supply apparatus which supplies cooling water to a furnace body. It is a graph which shows the temperature change cycle about the circumferential direction of an iron skin. It is a graph which illustrates an example of the cooling water supply method in an embodiment in time. It is a typical explanatory view showing an example of an iron skin temperature measurement and tracking control method in an embodiment. It is typical explanatory drawing which shows an example of protection operation at the time of the furnace body lower part passage in embodiment. It is a graph which compares and shows the conventional method which does not measure the temperature of an iron skin, and the method of the present invention. It is a graph which shows the temperature distribution of the furnace body circumferential direction measured from right beside the furnace body circumference. For the comparative example, Example 1, Example 2 that supplies a certain amount of cooling water, and the four types when Example 1 and Example 2 are performed together, the ratio of the deviated time to the total operation time is compared. It is a graph shown. When the cooling water is supplied only to a portion exceeding the temperature control value of the iron skin with the cooling water amount being constant (curve G), and when the appropriate cooling water amount is supplied as variable according to the temperature results (curve I). It is a graph shown by comparison. It is a graph which shows the change of the temperature of an iron skin based on the difference in the supply pattern of cooling water. It is a graph which shows the temperature measurement result of an iron shell in the timing which a refractory wear part passes each part of a furnace body circumferential direction. When the furnace in which the local wear part of the refractory exists is operated for 300 hours, the temperature of the iron shell in one wear part of each example exceeds 400 ° C. which is the upper limit control value, and the lower limit control value It is a graph which shows the relationship between the ratio of the time which went out with respect to the total operation time, and the refractory life about each when 200 degreeC is interrupted.

Claims (8)

The temperature of the surface of the iron skin constituting the furnace body of the rotary furnace is measured for each part in the furnace body circumferential direction, and the part concerned is compared with the part where the measured temperature deviates from the predetermined management temperature range. By passing a cooling water supply unit for supplying cooling water to the outer surface of the iron skin, by supplying a desired amount of cooling water, the temperature of the deviated portion is set within the management temperature range, and the management When the portion in the circumferential direction of the furnace body that deviates from the temperature range does not pass through the lower part of the furnace body, the rotational speed of the furnace body is set to (1/20) rpm or more (1/10) rpm or less, and the management temperature A method for protecting the iron core of a rotary furnace, characterized in that, when a portion in the circumferential direction of the furnace body that deviates from the zone passes through the lower part of the furnace body, the rotational speed of the furnace body is more than (1/10) rpm . The temperature of the surface of the iron skin constituting the furnace body of the rotary furnace is measured for each part in the furnace body longitudinal direction and for each part in the furnace body circumferential direction, and the temperature measured in the furnace body longitudinal direction is The amount of cooling water supplied to the outer surface of the iron shell from each of the plurality of cooling water supply units arranged in the furnace body longitudinal direction with respect to the part that deviates from the defined management temperature range, the plurality of cooling water supply units While adjusting each separately, the site | part from which the said temperature measured about the said furnace body circumferential direction deviated from the predetermined management temperature range passes the cooling water supply part which supplies cooling water to the outer surface of the said iron skin. Sometimes, by supplying a desired amount of cooling water, the temperature of the deviated portion is set in the management temperature range, and the portion in the furnace body circumferential direction deviating from the management temperature range passes through the lower portion of the furnace body. By the time other than the time, the rotational speed of the furnace body ( / 20) rpm or more (1/10) rpm or less, and when a portion in the furnace body circumferential direction that deviates from the control temperature range passes through the lower part of the furnace body, the rotational speed of the furnace body is (1/10) A method for protecting the iron core of a rotary furnace, characterized in that the rpm exceeds .   The method for protecting an iron skin of a rotary furnace according to claim 1 or 2, wherein the supply amount of the cooling water from the cooling water supply unit is corrected based on a temperature record of the iron skin.   Further, after the cooling water is supplied, the supply of the cooling water is stopped for a predetermined time, and then the temperature of the iron skin is measured. When the temperature rises again and deviates from the temperature control area, the cooling water is supplied. The method for protecting an iron skin of a rotary furnace according to any one of claims 1 to 3, wherein the supply of the iron is resumed.   The supply of the cooling water to the part that deviates from the control temperature range, or the adjustment of the rotation speed of the furnace body is performed between the temperature measurement point and the cooling water supply unit, or from the temperature measurement point to the furnace body lower part. The method for protecting an iron skin of a rotary furnace according to any one of claims 1 to 4, wherein the method is performed by tracking temperature and position information of the part. The said management temperature range is 400 degrees C or less, The protection method of the iron core of the rotary furnace described in any one of Claim 1-5 . When the thickness of the refractory of the rotary furnace is 200 to 400 mm, the management temperature is 200 ° C or higher. The iron core of the rotary furnace according to any one of claims 1 to 6. Protection method. The temperature of the surface of the iron skin is measured at a portion of the surface of the iron skin where the cooling water is not directly applied. The iron of the rotary furnace according to any one of claims 1 to 7. Skin protection method.

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