JP2020152963A - Cooling method and coolant circulation system - Google Patents

Abstract

To provide a simple structure for cooling a member.SOLUTION: There is provided a method for cooling a member 10 in which a first flow path 11 and a second flow path 12 having inflow ports 11a and 12a and outflow ports 11b and 12b arranged at positions different from each other for cooling water W. The member 10 is used for a metal melting furnace in a state in which the first flow path 11 is disposed in a higher temperature environment than the second flow path 12. The cooling method includes a first mode in which the cooling water W is supplied to the first flow path 11 and circulated and then the cooling water W discharged from the first flow path 11 is supplied to the second flow path 12 to be circulated.SELECTED DRAWING: Figure 1

Description

The present invention relates to a cooling method and a refrigerant flow system.

Conventionally, the tuyere described in Patent Document 1 below is known. This tuyere has a front cooling chamber and a rear cooling chamber.
A high-pressure water supply device is connected to the front cooling chamber. As a result, the cooling efficiency on the front side of the tuyere exposed to high temperature can be increased.
A low-pressure water supply device is connected to the rear cooling chamber. As a result, the rear side of the tuyere, which is not exposed to the high temperature of the front side, is not excessively cooled, so that it is possible to suppress an excessive temperature drop of hot air passing through the tuyere.

JP-A-53-73404

However, in the conventional tuyere, for example, when this tuyere is newly applied to a blast furnace using a once-through tuyere, two water supply devices are required. Therefore, the installation construction period becomes long and the installation cost becomes high.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method or system capable of cooling a member with a simple structure.

In order to solve the above problems, the present invention proposes the following means.
The cooling method according to the present invention is a method of cooling a member in which a first flow path and a second flow path having different inlets and outlets of the refrigerant are formed, and the member is the first flow path. Is used in a metal melting furnace in a state where it is arranged in a higher temperature environment than the second flow path, and after supplying the refrigerant to the first flow path and distributing it, it is discharged from the first flow path. A first mode is provided in which the refrigerant is supplied to the second flow path and distributed.

In the first mode, the refrigerant is supplied to the first flow path and distributed, and then the refrigerant discharged from the first flow path is supplied to the second flow path and distributed. Therefore, it is not necessary to independently supply the refrigerant to each of the first flow path and the second flow path, and the refrigerant may be supplied to the second flow path through the first flow path. This makes it possible to simplify the structure of the system that distributes the refrigerant through the members. In the first mode, a pressure loss occurs in the refrigerant when the refrigerant flows through the first flow path, and when the refrigerant discharged from the first flow path flows through the second flow path, the pressure is naturally low. ..
In the present invention, for example, in a blast furnace in which a once-through tuyere (a tuyere with one channel) is used, a channel-separated tuyere (a tuyere with two or more channels, so-called parent-child tuyere, etc. ) Is effective when newly introduced. For example, when a tuyere whose flow path is divided into a tip (first flow path) and a body (second flow path) of the tuyere is newly introduced, the pump is usually strengthened (additional). , Piping laying, drainage capacity enhancement, etc. are required. However, in the present invention, since the refrigerant discharged from the tip portion is supplied to the body portion in cascade, it is not necessary to increase the pump, and the piping work can be completed within a limited range. This also applies to a tuyere in which the flow path is divided into an outer side (first flow path) and an inner side (second flow path) of the tuyere.

In the cooling method according to the present invention, in the first mode, the average flow velocity of the refrigerant in the first flow path may be higher than the average flow velocity of the refrigerant in the second flow path.

By supplying the refrigerant to the first flow path arranged in the high temperature environment at high speed, the member can be effectively cooled.

The cooling method according to the present invention further includes a second mode in which the refrigerant is supplied to the second flow path without passing through the first flow path, and the first flow path is operated during operation in the first mode. When it is damaged, the first mode may be switched to the second mode.

In the second mode, the refrigerant is supplied to the second flow path without passing through the first flow path, and the first mode and the second mode can be switched. Therefore, when the first flow path is damaged during the operation in the first mode, by switching the first mode to the second mode, it is possible to prevent the refrigerant from being supplied to the damaged first flow path. .. This makes it possible to prevent the refrigerant from leaking into the metal melting furnace (for example, the blast furnace) and the temperature drop / cooling in the metal melting furnace (for example, the blast furnace).
In the second mode, the refrigerant is supplied to the second flow path without passing through the first flow path. Therefore, for example, when the first flow path is damaged and the second flow path is operated only in the second flow path, the refrigerant balances the pressure loss of the entire system and the flow rate of the refrigerant flowing through the second flow path is increased. Since the number increases, the flow velocity of the refrigerant flowing through the second flow path can be increased. Further, the refrigerant flowing through the second flow path does not have a pressure loss due to the first flow path. Therefore, the speed and pressure of the refrigerant flowing through the second flow path can be increased. As a result, the member can be effectively cooled even when the first flow path is damaged, and the life of the member can be extended, for example.

In the cooling method according to the present invention, the metal melting furnace is a blast furnace, the member is a tuyere, the refrigerant is water, and in the second mode, the average flow velocity of the refrigerant in the second flow path is It may be 5 m / s or more.

In the second mode, the average flow velocity of the refrigerant in the second flow path is 5 m / s or more. Thereby, the occurrence of burnout can be effectively prevented. That is, when the average flow velocity of the refrigerant is reduced to less than 5 m / s, the possibility of burnout due to the dropping of hot metal increases. The lower limit of the average flow velocity of the refrigerant in which burnout occurs decreases as the pressure of the refrigerant increases. Therefore, as in the second mode, the refrigerant is supplied to the second flow path without passing through the first flow path and is not subjected to pressure loss, and the pressure of the refrigerant flowing through the second flow path is increased. Is convenient from the viewpoint of burnout prevention. The burnout is a state immediately before the refrigerant continuously boils, and the heat flux at this time is called a burnout heat flux. When the burnout heat flux is exceeded, the refrigerant transitions from nucleate boiling to film boiling, and the heat transfer surface is covered with a vapor film, so that the heat removal effect of the refrigerant is significantly reduced and the tuyere is melted.

The cooling method according to the present invention further increases a transition mode in which the flow rate of the refrigerant supplied to the second flow path without passing through the first flow path is gradually increased from the state of operating in the first mode. When the amount of the refrigerant flowing out from the second flow path becomes lower than the amount of the refrigerant flowing into the first flow path during the operation in the first mode, the operation is performed in the transition mode. It may be determined whether the first flow path or the second flow path is damaged based on the inflow amount and the outflow amount during the operation in the transition mode.

During operation in the first mode, normally, the inflow amount of the refrigerant into the first flow path and the outflow amount of the refrigerant from the second flow path are equivalent.
However, when the first flow path or the second flow path is damaged, the refrigerant leaks from the damaged flow path, and the outflow amount becomes lower than the inflow amount. In other words, when the outflow amount becomes lower than the inflow amount, it is presumed that the first flow path or the second flow path is damaged.
In this method, when the outflow amount of the refrigerant from the second flow path becomes lower than the inflow amount of the refrigerant into the first flow path during the operation in the first mode, that is, the first flow path or the second flow path. Operate in transition mode when it is presumed that the flow path is damaged. In the transition mode, the flow rate of the refrigerant supplied to the second flow path without passing through the first flow path is gradually increased from the state of operating in the first mode.
At this time, since the flow rate of the refrigerant supplied to the first flow path decreases, if the first flow path is damaged, the amount of refrigerant leaking from the entire flow path decreases. Therefore, when the mode is switched from the first mode to the transition mode, the difference between the inflow amount and the outflow amount becomes small.
On the other hand, at this time, since the flow rate of the refrigerant supplied to the second flow path does not decrease, even if the second flow path is damaged, the amount of the refrigerant leaking from the entire flow path does not decrease. Therefore, even if the mode is switched from the first mode to the transition mode, the difference between the inflow amount and the outflow amount does not become small.
Therefore, it is possible to determine which of the first flow path and the second flow path is damaged based on the inflow amount and the outflow amount during the operation in the transition mode.

By the way, in this method, the mode is not instantaneously switched from the first mode to the second mode, but is gradually switched from the first mode to the second mode through the transition mode.
Here, in the case of momentarily switching from the first mode to the second mode, if the first flow path is not damaged, the refrigerant may be trapped in the first flow path. In this case, the refrigerant contained in the first flow path expands when exposed to a high temperature, and the first flow path may be damaged (although it was not damaged).
On the other hand, when gradually switching from the first mode to the second mode through the transition mode as in this method, as described above, as compared with the case of instantaneously switching from the first mode to the second mode. There is little risk of damage to the first flow path.

During the operation in the first mode, the inflow amount of the refrigerant into the first flow path, the flow amount of the refrigerant from the first flow path to the second flow path, and the flow rate of the refrigerant from the second flow path. Based on the outflow amount of the refrigerant, it may be determined which of the first flow path and the second flow path is damaged.

During operation in the first mode, normally, the inflow amount of the refrigerant into the first flow path (hereinafter, simply referred to as the inflow amount) and the flow amount of the refrigerant from the first flow path to the second flow path (hereinafter, simply referred to as the inflow amount). , Simply referred to as the flow rate) and the outflow amount of the refrigerant from the second flow path (hereinafter, simply referred to as the outflow amount) are equivalent.
However, when the first flow path or the second flow path is damaged, the refrigerant leaks from the damaged flow path, and the relationship between the inflow amount, the flow amount, and the outflow amount changes. That is, when at least one of the first flow path and the second flow path is damaged, the outflow amount becomes lower than the inflow amount. When only the first flow path is damaged, the inflow rate, which is the flow rate of the refrigerant before passing through the first flow path, is high, and the flow rate, which is the flow rate of the refrigerant after passing through the first flow path, and the flow rate. The outflow will be as low. On the other hand, when only the second flow path is damaged, the inflow rate and the flow rate, which are the flow rates of the refrigerant before passing through the second flow path, are equally high, and after passing through the second flow path. The outflow rate, which is the flow rate of the refrigerant, becomes low.
Therefore, it is possible to determine which of the first flow path and the second flow path is damaged by comparing the inflow amount, the flow amount, and the outflow amount based on the inflow amount, the flow amount, and the outflow amount. Can be done.

In the cooling method according to the present invention, when the refrigerant is a liquid and the refrigerant vaporizes in the first flow path, the vaporized refrigerant may flow out from the inflow port of the first flow path.

According to this cooling method, even if the refrigerant is vaporized and expanded while the refrigerant is contained in the first flow path, the expanded refrigerant can escape to the outside of the first flow path. Therefore, the expanded refrigerant is discharged in a predetermined direction (direction without an inspector, etc.) without being ejected from an unexpected place such as a flange connected to the first flow path outside the furnace. , The safety of work such as inspection can be improved.

The refrigerant flow system according to the present invention is a refrigerant flow system in which a refrigerant is circulated to a member in which a first flow path and a second flow path in which the inlet and outlet of the refrigerant are different from each other are formed. The first flow path is used in a metal melting furnace in a state where the first flow path is arranged in a higher temperature environment than the second flow path, and the refrigerant flow system includes a pump that delivers the refrigerant, the pump, and the first flow. The first pipe connecting the inlet of the road, the second pipe connecting the outlet of the first flow path and the inlet of the second flow path, and the first pipe and the second pipe The third pipe to be connected, the first valve provided in the first pipe on the downstream side of the connection portion with the third pipe, and the second pipe in the second pipe than the connection portion with the third pipe. A second valve provided on the upstream side and a third valve provided on the third pipe are provided.

Normally, the refrigerant distribution system can be operated in the first mode. In the first mode, the refrigerant is supplied to the first flow path and distributed, and then the refrigerant discharged from the first flow path is supplied to the second flow path and distributed. At this time, the refrigerant is supplied from the pump to the first pipe with the first valve and the second valve opened and the third valve closed.
Further, when the first flow path is damaged during the operation in the first mode, the first mode can be switched to the second mode. In the second mode, the refrigerant is supplied to the second flow path without passing through the first flow path. At this time, the refrigerant is supplied from the pump to the first pipe with the first valve and the second valve closed and the third valve open.
As described above, according to this refrigerant distribution system, the operation in the first mode and the second mode can be realized.

In the refrigerant distribution system according to the present invention, the average cross section of the first flow path may be smaller than the average cross section of the second flow path.

By reducing the average cross section of the first flow path to the average cross section of the second flow path, the average flow velocity of the refrigerant flowing through the first flow path is made higher than the average flow velocity of the refrigerant flowing through the second flow path. be able to.

The refrigerant flow system according to the present invention comprises a fourth pipe connected to the outlet of the second flow path, a first measuring instrument for measuring the flow rate of the refrigerant flowing through the first pipe, and the second pipe. A second measuring device for measuring the flow rate of the flowing refrigerant and a third measuring device for measuring the flow rate of the refrigerant flowing through the fourth pipe may be further provided.

The first measuring instrument, the second measuring instrument, and the third measuring instrument measure the flow rate of the refrigerant flowing through the first pipe, the second pipe, and the fourth pipe, respectively. Therefore, these three measuring instruments measure the inflow amount of the refrigerant into the first flow path, the flow amount of the refrigerant from the first flow path to the second flow path, and the outflow amount of the refrigerant from the second flow path. can do. By comparing the inflow amount, the flow amount, and the outflow amount, it is possible to determine which of the first flow path and the second flow path is damaged as described above.

The refrigerant distribution system according to the present invention is provided with a safety valve provided in the first pipe, and when the refrigerant is vaporized in the first flow path, the vaporized refrigerant flows out from the inflow port of the first flow path. Further may be provided.

According to the present invention, even if the refrigerant evaporates and expands while the refrigerant is contained in the first flow path, the expanded refrigerant is still present in the inflow port of the first flow path, the first pipe, and the safety valve. Through it, it can escape to the outside of the first flow path. Therefore, as described above, the safety of work such as inspection can be enhanced.

The refrigerant flow system according to the present invention further includes the pump and a control device for controlling the third valve from the first valve, and the control device opens the first valve and the second valve, and the third valve is opened. The refrigerant may be supplied from the pump to the first pipe with the valve closed.

As a result, the refrigerant distribution system can be operated in the first mode. Therefore, for example, the operation in the first mode can be realized without any operation by the operator.

According to the present invention, the member can be cooled with a simple structure.

It is a schematic block diagram of the tuyere and the refrigerant flow system which concerns on one Embodiment of this invention, and is the figure which shows the operation in the 1st mode. It is a figure which looked at the tuyere and the refrigerant flow system shown in FIG. 1 from the outside of the blast furnace. It is sectional drawing of the tuyere and the refrigerant flow system shown in FIG. It is a schematic block diagram of the tuyere and the refrigerant flow system which concerns on one Embodiment of this invention, and is the figure which shows the operation in the 2nd mode. It is a figure which looked at the tuyere and the refrigerant flow system shown in FIG. 4 from the outside of the blast furnace. It is sectional drawing of the tuyere and the refrigerant flow system shown in FIG. It is a flowchart explaining the 1st cooling method for cooling the tuyere shown in FIGS. 1 to 6. 6 is a flowchart illustrating a second cooling method for cooling the tuyere shown in FIGS. 1 to 6. It is sectional drawing of the cooling plate and the refrigerant flow system which concerns on one modification of this invention. It is a block diagram which shows the tuyere and the refrigerant flow system used for the estimation of a pressure loss, and is the figure which shows the operation in the 1st mode. It is a block diagram which shows the tuyere and the refrigerant flow system used for the estimation of the pressure loss, and is the figure which shows the operation in the 2nd mode.

Hereinafter, the refrigerant distribution system 20 and the cooling method according to the embodiment of the present invention will be described with reference to FIGS. 1 to 8. The refrigerant distribution system 20 and the cooling method cool the tuyere 10 by circulating cooling water W as a refrigerant through the tuyere 10 (member). In explaining the refrigerant distribution system 20 and the cooling method, the tuyere 10 will be described first.
The tuyere 10 shown in FIG. 3 is used for a blast furnace (metal melting furnace). The tuyere 10 blows gas (hot air) from the outside to the inside of the blast furnace. In the following, the inner side of the blast furnace along the axis of the tuyere 10 is referred to as the front side D1, and the outer side of the blast furnace is referred to as the rear side D2.

In the present embodiment, the tuyere 10 is a so-called parent-child tuyere (double tuyere). Two flow paths 11 and 12 are formed in the tuyere 10. The tuyere 10 includes a first flow path 11 and a second flow path 12 as two flow paths 11 and 12. In the first flow path 11 and the second flow path 12, the inflow ports 11a and 12a of the cooling water W (refrigerant and liquid) and the outflow ports 11b and 12b are different from each other. That is, the inflow port 11a of the first flow path 11 and the inflow port 12a of the second flow path 12 are different, and the outflow port 11b of the first flow path 11 and the outflow port 12b of the first flow path are different. The first flow path 11 and the second flow path 12 are independent flow paths. In other words, the first flow path 11 and the second flow path 12 do not have a portion shared with each other.

A part of the tuyere 10 is cooled by the cooling water W flowing through the flow paths 11 and 12. The first flow path 11 cools the portion located on the front side D1 of the tuyere 10 as compared with the second flow path 12. The first flow path 11 is formed at the tip of the tuyere 10 and cools the tip of the tuyere 10. The second flow path 12 is formed in the body portion of the tuyere 10, and cools the body portion of the tuyere 10. The tuyere 10 is arranged in a higher temperature environment (front side D1, closer to the inside of the blast furnace) than the second flow path 12 (flow path for cooling the body) of the first flow path 11 (flow path for cooling the tip). Used in the blast furnace in the state of being The cooling water W flowing in from the inflow port 11a of the first flow path 11 flows out from the outflow port 11b of the first flow path 11 without flowing through the second flow path 12. The cooling water W flowing in from the inflow port 12a of the second flow path 12 flows out from the outflow port 12b of the second flow path 12 without flowing through the first flow path 11.

Next, the refrigerant distribution system 20 will be described.
As shown in FIGS. 1 to 3, the refrigerant distribution system 20 cools the tuyere 10 by circulating cooling water W through the tuyere 10. The temperature of the cooling water W may be such that the tuyere 10 can be cooled, and the cooling water W may have a high temperature as water. The cooling water W normally flows through the flow paths 11 and 12 in the range of 20 to 40 ° C. Further, the cooling water W also includes drainage that has cooled the tuyere 10 and received a certain amount of heat from the tuyere 10.

The refrigerant distribution system 20 includes a pump 30, a plurality of pipes 41, 42, 43, 44, a plurality of valves 51, 52, 53, 54, a plurality of measuring instruments 61, 62, 63, a control device 70, and the like. Is equipped with.

As shown in FIG. 1, the pump 30 delivers the cooling water W. The pump 30 sends (transfers, pumps) the cooling water W supplied to the pump 30 from a water supply source (not shown) to the tuyere 10. The pump 30 adjusts the delivery amount of the cooling water W. The pump 30 is an electric pump.
In the illustrated example, two (plural) pumps 30 are arranged in parallel. As a result, even if one pump 30 fails, the operation can be continued by switching to the remaining one pump 30. However, the number of pumps 30 may be one. Further, a plurality of pumps 30 may be provided in an amount of three or more.

The refrigerant distribution system 20 includes a first pipe 41, a second pipe 42, a third pipe 43, and a fourth pipe 44 as a plurality of pipes 41, 42, 43, 44.
The first pipe 41 connects the pump 30 and the inflow port 11a of the first flow path 11. The first pipe 41 causes the cooling water W sent out from the pump 30 to flow into the first flow path 11. In the illustrated example, the first pipe 41 includes two (plural) branch pipes 41a extending from each of the two pumps 30, and a main pipe 41b at which the two branch pipes 41a join. The main pipe 41b is connected to the inflow port 11a of the first flow path 11. A header pipe 45 (see FIGS. 10 and 11) may be provided between the pump 30 and the first pipe 41.

The second pipe 42 connects the outflow port 11b of the first flow path 11 and the inflow port 12a of the second flow path 12. The second pipe 42 causes the cooling water W flowing out of the first flow path 11 to flow into the second flow path 12.
The third pipe 43 connects the first pipe 41 and the second pipe 42. The third pipe 43 connects the main pipe 41b of the first pipe 41 and the second pipe 42. In the second mode described later, the third pipe 43 circulates the cooling water W flowing through the first pipe 41 to the second pipe 42 without passing through the first flow path 11.

The fourth pipe 44 is connected to the outlet 12b of the second flow path 12. The fourth pipe 44 discharges the cooling water W flowing out from the second flow path 12. The fourth pipe 44 discharges the cooling water W to, for example, a drainage header pipe, a drainage box, a drainage tank, or the like.

The refrigerant distribution system 20 includes a first valve 51, a second valve 52, a third valve 53, and a safety valve 54 as a plurality of valves 51, 52, 53, 54. The first valve 51 to the third valve 53 adjust the flow rate of the cooling water W flowing through the pipes 41, 42, 43, 44. In the present embodiment, the first valve 51 to the third valve 53 are electric, but may be manual.

The first valve 51 is provided in the first pipe 41. The first valve 51 is provided in the first pipe 41 on the downstream side of the connecting portion 46 with the third pipe 43. The downstream side of the first pipe 41 means the side where the first flow path 11 is located with respect to the first pipe 41. The upstream side of the first pipe 41 means the side where the pump 30 is located with respect to the first pipe 41.

The second valve 52 is provided in the second pipe 42. The second valve 52 is provided in the second pipe 42 on the upstream side of the connecting portion 47 with the third pipe 43. The upstream side of the second pipe 42 means the side where the first flow path 11 is located with respect to the second pipe 42. The downstream side of the second pipe 42 means the side where the second flow path 12 is located with respect to the second pipe 42.
The third valve 53 is provided in the third pipe 43.

As shown in FIG. 2, the safety valve 54 is provided in the first pipe 41. The safety valve 54 is provided in the first pipe 41 on the downstream side of the first valve 51. When the cooling water W is vaporized in the first flow path 11, the safety valve 54 causes the vaporized cooling water W to flow out (release) from the inflow port 11a of the first flow path 11. Therefore, even if the cooling water W is vaporized and expanded (boiling) while the cooling water W is contained in the first flow path 11, the expanded cooling water W is passed through the inflow port 11a to the first flow. You can escape to the outside of the road 11. Therefore, the expanded refrigerant is discharged in a predetermined direction (direction without an inspector or the like) without being ejected from an unexpected place such as a flange connected to the first flow path 11 outside the furnace. Therefore, the safety of work such as inspection can be improved.

As shown in FIG. 1, the refrigerant distribution system 20 includes a first measuring instrument 61, a second measuring instrument 62, and a third measuring instrument 63 as a plurality of measuring instruments 61, 62, 63. The first measuring instrument 61 to the third measuring instrument 63 are flow meters that measure the flow rate of the cooling water W flowing through the pipes 41, 42, and 44.
The first measuring instrument 61 measures the flow rate of the cooling water W flowing through the first pipe 41. The first measuring instrument 61 is provided in the first pipe 41 on the upstream side of the connecting portion 46 with the third pipe 43. The first measuring instrument 61 is provided in the main pipe 41b. The first measuring instrument 61 may be provided on the downstream side of the connecting portion 46 in the first pipe 41.

The second measuring instrument 62 measures the flow rate of the cooling water W flowing through the second pipe 42. The second measuring instrument 62 is provided in the second pipe 42. The second measuring instrument 62 is provided in the second pipe 42 on the downstream side of the connecting portion 47 with the third pipe 43. The second measuring instrument 62 may be provided on the upstream side of the connecting portion 47 in the second pipe 42.
The third measuring instrument 63 measures the flow rate of the cooling water W flowing through the fourth pipe 44. The third measuring instrument 63 is provided in the fourth pipe 44.

The control device 70 is composed of an information processing device. The control device 70 includes, for example, a CPU (Central Processor Unit) connected by a bus, a memory, and an auxiliary storage device. The control device 70 operates by executing a program.
The control device 70 is connected to the pump 30, the first valve 51 to the third valve 53, and the first measuring device 61 to the third measuring device 63, respectively. The control device 70 and various devices may be wiredly connected or wirelessly connected. The control device 70 controls the drive of the pump 30 and the first valve 51 to the third valve 53. The control device 70 acquires the measurement results of the first measuring device 61 to the third measuring device 63.

The control device 70 operates the refrigerant flow system 20 in two operation modes (first mode and second mode). The control device 70 switches between the first mode and the second mode. In other words, the control device 70 does not execute the first mode and the second mode in parallel. The control device 70 normally operates the refrigerant flow system 20 in the first mode. When the control device 70 determines that the first flow path 11 is damaged during the operation in the first mode, the control device 70 switches the first mode to the second mode.

The fact that the first flow path 11 is damaged means that, for example, a puncture hole communicating with the first flow path 11 is generated in the tuyere 10. In this case, the cooling water W flowing through the first flow path 11 may leak from the ruptured portion of the tuyere 10. Similarly, the damage of the second flow path 12 means that, for example, a breach communicating with the second flow path 12 occurs in the tuyere 10. In this case, the cooling water W flowing through the second flow path 12 may leak from the ruptured portion of the tuyere 10.

As shown in FIGS. 1 to 3, in the first mode, the refrigerant flow system 20 supplies the cooling water W to the first flow path 11 for distribution, and then discharges the cooling water from the first flow path 11. W is supplied to the second flow path 12 and distributed. That is, in the first mode, when the cooling water W flows through the first flow path 11, a pressure loss occurs in the cooling water W, and the cooling water W discharged from the first flow path 11 flows through the second flow path 12. When you do, the pressure is naturally decreasing.
At this time, the refrigerant flow system 20 opens the first valve 51 and the second valve 52 (both valves 51 and 52 are outlined in FIGS. 1 to 3) and closes the third valve 53 (FIG. 3). The third valve 53 is painted black in FIGS. 1 to 3), and the cooling water W is supplied from the pump 30 to the first pipe 41.

In the first mode, the average flow velocity of the cooling water W in the first flow path 11 is preferably higher than the average flow velocity of the cooling water W in the second flow path 12. As a result, the refrigerant can be supplied at high speed to the first flow path 11 arranged in the high temperature environment (that is, the risk of damage is high), and the tuyere 10 can be effectively cooled.
In order to make the average flow velocity of the cooling water W in the first flow path 11 higher than the average flow velocity of the cooling water W in the second flow path 12, for example, the following methods (1) and (2) are used. Conceivable.
(1) Make the average cross section of the first flow path 11 smaller than the average cross section of the second flow path 12.
(2) Cooling flowing through the first flow path 11 by directly draining a part of the cooling water W discharged from the first flow path 11 to the outside of the tuyere 10 without passing through the second flow path 12. The flow rate of the water W is increased to increase the average flow rate of the cooling water W in the first flow path 11. That is, regarding the drainage from the first flow path 11, a route for supplying the drainage to the second flow path 12 and a route for draining the water without supplying the second flow path 12 are provided, and the cooling flowing through the first flow path 11 is provided. By increasing the flow rate of the water W (the flow rate of the cooling water W flowing through the second flow path 12 is not increased), the average flow rate of the cooling water W in the first flow path 11 is increased.

As shown in FIGS. 4 to 6, in the second mode, the refrigerant flow system 20 supplies the cooling water W to the second flow path 12 without passing through the first flow path 11. Therefore, when operating in the second mode and operating only in the second flow path 12, the cooling water W flowing through the second flow path 12 does not have a pressure loss due to the first flow path 11. Therefore, the pressure of the cooling water W flowing through the second flow path 12 can be increased. Further, according to the second mode, the flow rate of the cooling water W flowing through the second flow path 12 is increased as compared with the first mode due to the pressure loss balance, so that the cooling water W flowing through the second flow path 12 is speeded up. Can be transformed into. Further, the increase margin of the speed at this time is larger as the average flow velocity in the first flow path 11 is larger than the average flow velocity in the second flow path 12 in the first mode.
At this time, the refrigerant flow system 20 is in a state where the first valve 51 and the second valve 52 are closed (both valves 51 and 52 are painted black in FIGS. 4 to 6) and the third valve 53 is opened ( The third valve 53 is outlined in FIGS. 4 to 6), and the cooling water W is supplied from the pump 30 to the first pipe 41.

In the present specification, the flow velocity of the cooling water W (refrigerant) is the flow rate (volumetric flow rate, for example, m ³ / s) of the cooling water W (refrigerant) divided by the cross-sectional area of the flow path (for example, m ² ). It refers to the linear flow velocity (m / s). Design the cross-sectional area (for example, inner diameter) of the first flow path 11 and the second flow path 12 where the cooling water W (refrigerant) of the same flow rate flows through the first flow path 11 and the second flow path 12. Therefore, a desired flow velocity can be obtained.
The cross section may differ depending on the position in the first flow path 11, or the cross section may differ depending on the position in the second flow path 12. At this time, the flow velocity of the cooling water W (refrigerant) differs depending on the position in the first flow path 11 (second flow path 12).
The average flow velocity of the cooling water W (refrigerant) in the first flow path 11 is the average cross-sectional area of the flow paths of the cooling water W (refrigerant) from the inflow port 11a to the outflow port 11b of the first flow path 11. The divided flow velocity means the average flow velocity of the cooling water W (refrigerant) in the second flow path 12, and the flow rate of the cooling water W (refrigerant) is the flow rate of the cooling water W (refrigerant) from the inflow port 12a to the outflow port 12b of the second flow path 12. The flow velocity divided by the average cross-sectional area of the road.

In the second mode, the average flow velocity in the second flow path 12 is preferably 5 m / s or more. According to a known experimental formula (for example, iron and steel Vol. 62, No. 9 (1976) p.1151-1158, Ukai et al., "Experimental study on tuyere erosion"), the cooling water W in which burnout occurs The flow velocity is expressed by the water temperature and pressure of the cooling water W, the melting point of the material of the tuyere 10, and the amount of heat to the tuyere 10. According to the study by the present inventors, the possibility of burnout can be effectively reduced by setting the flow velocity of the refrigerant in the second flow path 12 in the second mode to 5 m / s or more.

Next, a cooling method for the tuyere 10 (hereinafter, simply referred to as a cooling method) will be described. In the present embodiment, two cooling methods, a first cooling method and a second cooling method, will be described as cooling methods.

In either of the first cooling method and the second cooling method, the control device 70 controls the refrigerant distribution system 20 based on the measurement results of the plurality of measuring instruments 61, 62, 63, and the tuyere 10 To cool. Specifically, the control device 70 executes the control as shown below.
(1) The control device 70 operates the refrigerant distribution system 20 in the first mode.
(2) The control device 70 determines from the measurement results of the plurality of measuring instruments 61, 62, 63 whether at least one of the first flow path 11 and the second flow path 12 is damaged.
(3) When it is determined that at least one of the first flow path 11 and the second flow path 12 is damaged, the control device 70 determines which of the first flow path 11 and the second flow path 12 is damaged. To judge.
(4-1) When it is determined that the first flow path 11 is damaged, the control device 70 operates the refrigerant flow system 20 in the second mode.
(4-2) When it is determined that the second flow path 12 is damaged, the control device 70 notifies the operator of the damage of the second flow path 12 by a notification means (for example, an alarm) (not shown).

The control device 70 stores and executes at least one of a program that implements the first cooling method and a program that implements the second cooling method. In other words, the control device 70 does not necessarily have to be able to execute both programs.

(First cooling method)
In the first cooling method, the control device 70 operates the refrigerant flow system 20 based on the measurement results of the first measuring device 61 to the third measuring device 63. In the first cooling method, the control device 70 determines which of the first flow path 11 and the second flow path 12 is damaged based on the measurement results of the first measuring device 61 to the third measuring device 63. To do. Based on the determination, the control device 70 switches the operation mode of the refrigerant distribution system 20 and notifies the operator of the determination result.

In the first cooling method, during operation in the first mode, the control device 70 determines the inflow amount Q1 of the cooling water W into the first flow path 11 (that is, the measurement result of the first measuring instrument 61) and the first. The flow amount Q2 of the cooling water W from the flow path 11 to the second flow path 12 (that is, the measurement result of the second measuring instrument 62) and the outflow amount Q3 of the cooling water W from the second flow path 12 (that is, the first 3 It is determined which of the first flow path 11 and the second flow path 12 is damaged based on the measurement result of the measuring instrument 63).
In the following, first, the control device 70 determines which of the first flow path 11 and the second flow path 12 is damaged based on the measurement results of the first measuring device 61 to the third measuring device 63. Explain why you can do it.

During operation in the first mode as shown in FIGS. 1 to 3, normally, the inflow amount Q1 of the cooling water W into the first flow path 11 and the flow from the first flow path 11 to the second flow path 12 The flow amount Q2 of the cooling water W and the outflow amount Q3 of the cooling water W from the second flow path 12 are equivalent.
However, when the first flow path 11 or the second flow path 12 is damaged, the cooling water W leaks from the damaged flow path, and the relationship between the inflow amount Q1, the flow amount Q2, and the outflow amount Q3 changes. That is, when at least one of the first flow path 11 and the second flow path 12 is damaged, the outflow amount Q3 becomes lower than the inflow amount Q1. When only the first flow path 11 is damaged, the inflow amount Q1 which is the flow rate of the cooling water W before passing through the first flow path 11 is high, and the cooling water after passing through the first flow path 11 is high. The flow rate Q2 and the outflow amount Q3, which are the flow rates of W, are similarly low. On the other hand, when only the second flow path 12 is damaged, the inflow amount Q1 and the flow rate Q2, which are the flow rates of the cooling water W before passing through the second flow path 12, are equally high, and the second flow rate. The outflow amount Q3, which is the flow rate of the cooling water W after passing through the road 12, becomes low.
Therefore, by comparing the inflow amount Q1, the flow amount Q2, and the outflow amount Q3 based on the inflow amount Q1, the flow amount Q2, and the outflow amount Q3, which of the first flow path 11 and the second flow path 12 is It can be determined whether it is damaged.

Next, the flow of the first cooling method will be described with reference to the flowchart shown in FIG.

First, during normal operation, the control device 70 operates the refrigerant distribution system 20 in the first mode (S1). At this time, the control device 70 controls the pump 30 and the first valve 51 to the third valve 53 to operate the refrigerant flow system 20 in the first mode.
While operating the refrigerant flow system 20 in the first mode, the control device 70 periodically determines whether the first flow path 11 and the second flow path 12 are damaged (S2). The control device 70 determines whether the first flow path 11 and the second flow path 12 are damaged, for example, at 1-minute intervals.

In making this determination, specifically, first, the control device 70 receives the measurement results from the first measuring instrument 61 to the third measuring instrument 63 (S21).
The control device 70 that has received the measurement result makes the first determination (S22). In the first determination, it is determined whether or not at least one of the first flow path 11 and the second flow path 12 is damaged. Specifically, in the first determination, the control device 70 determines whether or not the outflow amount Q3 is constant or lower than the inflow amount Q1. By determining whether or not the outflow amount Q3 is lower than the inflow amount Q1, the control device 70 determines whether or not at least one of the first flow path 11 and the second flow path 12 is damaged, as described above. You can judge.

In the first judgment, it is not simply determined whether or not the outflow amount Q3 is lower than the inflow amount Q1, but it is determined, for example, whether or not the outflow amount Q3 is "constant amount" lower than the inflow amount Q1. The purpose is to eliminate the effects of errors and the like. As the constant amount, for example, a value of 1% of the inflow amount Q1 can be adopted. That is, whether or not the value ((Q1-Q3) / Q1) obtained by dividing the difference between the inflow amount Q1 and the outflow amount Q1 by the inflow amount Q1 is larger than 1% can be used as the criterion for the first determination. However, in the first determination, it may be simply determined whether or not the outflow amount Q3 is lower than the inflow amount Q1.

When the outflow amount Q3 is lower than the inflow amount Q1 (S22-YES), the control device 70 can determine that the first flow path 11 or the second flow path 12 is damaged as described above. Therefore, the control device 70 proceeds to the second determination (S23). When the outflow amount Q3 is not lower than the inflow amount Q1 (S22-NO), the control device 70 can determine that neither the first flow path 11 nor the second flow path 12 is damaged. The mode operation is continued (S1).

In the second determination (S23), the control device 70 determines whether or not only the first flow path 11 is damaged. Specifically, in the second determination, the control device 70 determines whether or not the distribution amount Q2 and the outflow amount Q3 are equivalent. When only the first flow path 11 is damaged, as described above, the flow rate Q2 and the outflow amount Q3, which are the flow rates of the cooling water W after passing through the first flow path 11, are the first flow path. It is about the same as the inflow amount Q1 which is the flow rate of the cooling water W before passing through 11. Therefore, the control device 70 can determine whether or not only the first flow path 11 is damaged, as described above, by determining whether or not the distribution amount Q2 and the outflow amount Q3 are equivalent. it can.

When the distribution amount Q2 and the outflow amount Q3 are the same, not only when the distribution amount Q2 and the outflow amount Q3 are completely equal, but also when there is a slight difference between the distribution amount Q2 and the outflow amount Q3. It may be included. In this case, for example, a value of 1% of the inflow amount Q1 can be adopted as the slight difference. The purpose of recognizing the slight difference is to eliminate the influence of measurement error, for example.

When the flow amount Q2 and the outflow amount Q3 are equivalent (S23-YES), the control device 70 can determine that only the first flow path 11 is damaged as described above. Therefore, the control device 70 switches the operation mode of the refrigerant distribution system 20 from the first mode to the second mode, and operates the refrigerant distribution system 20 in the second mode (S3). At this time, the control device 70 controls the pump 30 and the first valve 51 to the third valve 53 to operate the refrigerant flow system 20 in the second mode.

When the flow amount Q2 and the outflow amount Q3 are not equivalent (S23-NO), in the control device 70, not only the first flow path 11 is damaged, but only the second flow path 12 is damaged, or the control device 70 is damaged. , It can be determined that both the first flow path 11 and the second flow path 12 are damaged. Therefore, the control device 70 issues an alarm to notify the operator of the damage to the second flow path 12, and requests the operator to make a decision to temporarily suspend the blast furnace and replace the tuyere 10 (S4). In this case, for example, the operation of the entire blast furnace is stopped, and the tuyere 10 is replaced.

When operating in the second mode (S3), the control device 70 periodically determines whether the second flow path 12 is damaged while operating the refrigerant distribution system 20 in the second mode (S5). The control device 70 determines whether the second flow path 12 is damaged, for example, at 1-minute intervals.
In making this determination, the control device 70 periodically receives the measurement results of the first measuring instrument 61 (or the second measuring instrument 62) and the third measuring instrument 63 (S51). Next, the control device 70 determines whether or not the outflow amount Q3 is constant or lower than the inflow amount Q1 (S52). As the constant amount, for example, a value of 1% of the inflow amount Q1 can be adopted.

When the outflow amount Q3 is lower than the inflow amount Q1 (S52-YES), the control device 70 can determine that the second flow path 12 is damaged, and therefore issues an alarm to notify the operator that the second flow path 12 is damaged. We will inform you and request a decision to temporarily suspend the blast furnace and replace the tuyere 10 (S4). When the outflow amount Q3 is not lower than the inflow amount Q1 (S52-NO), the control device 70 can determine that the second flow path 12 is not damaged, and therefore continues the operation in the second mode (S3).

The tuyere 10 can be cooled by the first cooling method as described above.
By the way, during the operation in the second mode, for example, molten iron in the blast furnace may adhere to the damaged portion (hole portion) of the first flow path 11 that has been damaged, and the damaged portion may be blocked. In this case, the cooling water W is sealed in the first flow path 11. In this state, the cooling water W in the first flow path 11 is vaporized to become a high pressure in the first flow path 11, and there is a possibility that water vapor may be ejected from the first flow path 11. On the other hand, in the refrigerant distribution system 20, a safety valve 54 is provided in the first flow path 11, and the safety of work such as inspection can be enhanced.

(Second cooling method)
In the second cooling method, the control device 70 operates the refrigerant flow system 20 based on the measurement results of the first measuring device 61 and the third measuring device 63. In the second cooling method, the control device 70 determines which of the first flow path 11 and the second flow path 12 is damaged based on the measurement results of the first measuring device 61 and the third measuring device 63. To do. Based on the determination, the control device 70 switches the operation mode of the refrigerant distribution system 20 and notifies the operator of the determination result. When only the second cooling method is adopted, the refrigerant distribution system 20 may not have the second measuring instrument 62.

In the second cooling method, during operation in the first mode, the outflow amount Q3 of the cooling water W from the second flow path 12 (that is, the measurement result of the third measuring instrument 63) is cooled to the first flow path 11. When the inflow amount of water W becomes lower than Q1 (that is, the measurement result of the first measuring instrument 61), the control device 70 operates the refrigerant flow system 20 in the transition mode. In the transition mode, the control device 70 gradually increases the flow rate of the cooling water W supplied to the second flow path 12 without passing through the first flow path 11 from the state of operating in the first mode. The control device 70 determines which of the first flow path 11 and the second flow path 12 is damaged based on the inflow amount Q1 and the outflow amount Q3 during the operation in the transition mode.
In the following, first, the control device 70 determines which of the first flow path 11 and the second flow path 12 is damaged based on the measurement results of the first measuring device 61 and the third measuring device 63. Explain why you can do it.

During operation in the first mode, normally, the inflow amount Q1 of the cooling water W into the first flow path 11 and the outflow amount Q3 of the cooling water W from the second flow path 12 are equivalent.
However, when the first flow path 11 or the second flow path 12 is damaged, the cooling water W leaks from the damaged flow path, and the outflow amount Q3 becomes lower than the inflow amount Q1. In other words, when the outflow amount Q3 becomes lower than the inflow amount Q1, it is presumed that the first flow path 11 or the second flow path 12 is damaged.
In this method, when the outflow amount Q3 of the cooling water W from the second flow path 12 becomes lower than the inflow amount Q1 of the cooling water W into the first flow path 11 during the operation in the first mode, that is, , When it is presumed that the first flow path 11 or the second flow path 12 is damaged, the operation is performed in the transition mode. In the transition mode, the flow rate of the cooling water W supplied to the second flow path 12 without passing through the first flow path 11 is gradually increased from the state of operating in the first mode.
At this time, since the flow rate of the cooling water W supplied to the first flow path 11 decreases, if the first flow path 11 is damaged, the amount of cooling water W leaking from the entire flow path decreases. Therefore, when the mode is switched from the first mode to the transition mode, the difference between the inflow amount Q1 and the outflow amount Q3 becomes small.
On the other hand, at this time, since the flow rate of the cooling water W supplied to the second flow path 12 does not decrease, even if the second flow path 12 is damaged, the amount of the cooling water W leaking from the entire flow path does not decrease. .. Therefore, even if the mode is switched from the first mode to the transition mode, the difference between the inflow amount Q1 and the outflow amount Q3 does not become small.
Therefore, it is possible to determine which of the first flow path 11 and the second flow path 12 is damaged based on the inflow amount Q1 and the outflow amount Q3 during the operation in the transition mode.

Next, the flow of the second cooling method will be described with reference to the flowchart shown in FIG. When the same method as the first cooling method is carried out, the same numbers are assigned and the description thereof will be omitted.

First, during normal operation, the control device 70 periodically determines which of the first flow path 11 and the second flow path 12 is damaged while operating the refrigerant flow system 20 in the first mode (S1). (S6). The control device 70 determines which of the first flow path 11 and the second flow path 12 is damaged, for example, at 1-minute intervals.

In making this determination, specifically, first, the control device 70 receives the measurement results of the first measuring instrument 61 and the third measuring instrument 63 (S61).
The control device 70 that has received the measurement result makes the first determination (S62). In the first determination, it is determined whether or not at least one of the first flow path 11 and the second flow path 12 is damaged. This first determination is the same as the first determination (S22) in the first cooling method, and detailed description thereof will be omitted. In the first determination, the control device 70 determines whether or not the outflow amount Q3 is constant or lower than the inflow amount Q1.

When the outflow amount Q3 is lower than the inflow amount Q1 (S62-YES), the control device 70 can determine that the first flow path 11 or the second flow path 12 is damaged as described above. Therefore, the control device 70 stores the difference between the inflow amount Q1 and the outflow amount Q3 as the first difference Δ1 (S63), and then proceeds to the second determination (S64). When the outflow amount Q3 is not lower than the inflow amount Q1 (S62-NO), the control device 70 can determine that neither the first flow path 11 nor the second flow path 12 is damaged. The mode operation is continued (S1).

In the second determination (S64), in the control device 70, which of the first flow path 11 and the second flow path 12 is damaged (whether or not the first flow path 11 is damaged, the second flow path 12 is Whether it is damaged or not) is judged. Specifically, in the second determination, the control device 70 changes the opening degrees of the valves 51, 52, and 53 by a certain amount, and switches the operation mode of the refrigerant distribution system 20 from the first mode to the transition mode. Then, the control device 70 compares the first difference Δ1 with the second difference Δ2 which is the difference between the inflow amount Q1 and the outflow amount Q3 during the operation in the transition mode. When the second difference Δ2 is smaller than the first difference Δ1, the control device 70 can determine that the first flow path 11 is damaged as described above.

In the second determination, first, the control device 70 changes the opening degree of the first valve 51 to the third valve 53, and operates the refrigerant distribution system 20 in the transition mode (S641). At this time, the control device 70 closes the first valve 51 and the second valve 52 by a certain amount, and opens the third valve 53 by a certain amount, for example. Then, the control device 70 receives the measurement results (inflow amount Q1 and outflow amount Q3) from the first measuring device 61 and the third measuring device 63 (S642). After that, the control device 70 subtracts the outflow amount Q3 from the inflow amount Q1 to obtain the second difference Δ2 (S643), and determines whether or not the second difference Δ2 is a certain amount smaller than the first difference Δ1. (S644).

In the second judgment, it is not simply judged whether or not the second difference Δ2 is smaller than the first difference Δ1, but whether or not the second difference Δ2 is “a certain amount” smaller than the first difference Δ1. The purpose of determining whether or not is, for example, to eliminate the influence of measurement error. As the constant amount, for example, a value of 1% of the inflow amount Q1 can be adopted. However, in the second determination, it may be simply determined whether or not the second difference Δ2 is smaller than the first difference Δ1.

When the second difference Δ2 is smaller than the first difference Δ1 (S644-YES), the control device 70 can determine that the first flow path 11 is damaged as described above. Therefore, the control device 70 switches the operation mode of the refrigerant distribution system 20 from the first mode to the second mode, and operates the refrigerant distribution system 20 in the second mode (S3). Since the control after the operation in the second mode is the same as that in the first cooling method, the description thereof will be omitted.
When the second difference Δ2 is not smaller than the first difference Δ1 (S644-NO), it can be determined that the second flow path 12 is damaged, so that the control device 70 issues an alarm to the operator for the second difference. Notify that the flow path 12 is damaged, and request a decision to temporarily suspend the blast furnace and replace the tuyere 10 (S4).

The tuyere 10 can be cooled by the second cooling method as described above.
By the way, in this method, the mode is not instantaneously switched from the first mode to the second mode, but is gradually switched from the first mode to the second mode through the transition mode.
Here, in the case of instantaneously switching from the first mode to the second mode, if the first flow path 11 is not damaged, the cooling water W may be contained in the first flow path 11. There is. In this case, the cooling water W contained in the first flow path 11 may expand due to exposure to a high temperature, and the first flow path 11 may be damaged (even though it was not damaged). There is.
On the other hand, when gradually switching from the first mode to the second mode through the transition mode as in this method, as described above, as compared with the case of instantaneously switching from the first mode to the second mode. There is little risk that the first flow path 11 will be damaged.

In the second cooling method, the control device 70 determines in the first determination whether or not the outflow amount Q3 is a constant amount or lower than the inflow amount Q1 (S62), and then the inflow amount Q1 and the outflow amount Q3. The difference was stored as the first difference Δ1 (S63). However, the control device 70 first obtains the first difference Δ1 prior to the first determination, and at the time of the first determination, the first difference Δ1 is set to a predetermined threshold value (for example, 0 or 0 in consideration of the measurement error). It may be determined whether or not it is equal to or greater than (such as a large value).
Further, in the second cooling method, the control device 70 determines in the second determination based on the difference between the inflow amount Q1 and the outflow amount Q3 (that is, Q1-Q3 (in other words, Δ1 or Δ2)). However, it is not limited to this. For example, the control device 70 can make a judgment based on the ratio of the inflow amount Q1 and the outflow amount Q3 (that is, Q1 / Q3) in the second judgment.

As described above, according to the refrigerant flow system 20 and the cooling method according to the present embodiment, in the first mode, after the cooling water W is supplied to the first flow path 11 and distributed, the first flow path 11 The cooling water W discharged from the above is supplied to the second flow path 12 and distributed. Therefore, it is not necessary to supply the cooling water W to the first flow path 11 and the second flow path 12 independently, and the cooling water W may be supplied to the second flow path 12 through the first flow path 11. As a result, the structure of the system for distributing the cooling water W to the tuyere 10 can be simplified.

The refrigerant flow system 20 and the cooling method according to the present embodiment include, for example, a flow path separation type tuyere (two flow paths) in a blast furnace in which a once-through tuyere (a tuyere with one flow path) is used. It is effective when newly introducing the above tuyere, so-called parent-child tuyere, etc.). For example, when a tuyere 10 whose flow path is divided into a tip portion (first flow path 11) and a body portion (second flow path 12) of the tuyere 10 is newly introduced, normally, the pump 30 is used. Additional work such as reinforcement (expansion), piping laying, and drainage capacity enhancement is required. However, in the refrigerant distribution system 20 and the cooling method according to the present embodiment, since the cooling water W discharged from the tip portion is supplied in cascade to the body portion, it is not necessary to reinforce the pump 30, and the piping work is also limited. Can be done with. This also applies to the tuyere in which the flow path is divided into the outside (first flow path 11) and the inside (second flow path 12) of the tuyere.

In the second mode, the cooling water W is supplied to the second flow path 12 without passing through the first flow path 11, and the first mode and the second mode can be switched. Therefore, when the first flow path 11 is damaged during the operation in the first mode, the cooling water W is prevented from being supplied to the damaged first flow path 11 by switching the first mode to the second mode. can do. This makes it possible to prevent the leakage of the refrigerant into the blast furnace and the temperature drop / cooling in the blast furnace.

In the second mode, the cooling water W is supplied to the second flow path 12 without passing through the first flow path 11. Therefore, for example, when the first flow path 11 is damaged and the second flow path 12 is operated only in the second mode, the cooling water W balances the pressure loss of the entire system and makes the second flow path 12 Since the flow rate of the flowing cooling water W increases, the flow rate of the cooling water W flowing through the second flow path 12 can be increased. Further, the cooling water W flowing through the second flow path 12 does not have a pressure loss due to the first flow path 11. Therefore, the speed and pressure of the cooling water W flowing through the second flow path 12 can be increased. As a result, the tuyere 10 can be effectively cooled even when the first flow path 11 is damaged, and the life of the tuyere 10 can be extended, for example.

In the second mode, the average flow velocity of the cooling water W in the second flow path 12 is 5 m / s or more. Thereby, the occurrence of burnout can be effectively prevented. That is, when the average flow velocity of the cooling water W decreases to less than 5 m / s, the possibility of burnout occurring due to the dropping of hot metal increases. The lower limit of the average flow velocity at which burnout occurs decreases as the pressure of the cooling water W increases. Therefore, as in the second mode, the cooling water W is supplied to the second flow path 12 without passing through the first flow path 11 and is not subjected to pressure loss, and the cooling water W flows through the second flow path 12. It is convenient from the viewpoint of preventing burnout that the pressure is increased. The burnout is a state immediately before the cooling water W is continuously boiled, and the heat flux at this time is called a burnout heat flux. When the burnout heat flux is exceeded, the cooling water W transitions from nucleate boiling to film boiling, and the heat transfer surface is covered with a steam film, so that the heat removal effect of the cooling water W is significantly reduced and the tuyere 10 is melted. To.

The technical scope of the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

The member to which the refrigerant distribution system 20 and the cooling method are applied is not limited to the tuyere 10. For example, as shown in FIG. 9, the refrigerant distribution system 20 and the cooling method can be applied to the cooling plate 10A (member).
The members to which the refrigerant distribution system 20 and the cooling method are applied are not limited to the members used in the blast furnace. For example, it can be applied to a metal melting furnace other than a blast furnace, such as a cupola furnace.

All or a part of each function provided in the control device 70 described above may be realized by hardware such as ASIC (Application Specific Integrated Circuit), PLD (Programmable Logic Device), FPGA (Field Programmable Gate Array), or the like. ..
The program executed by the control device 70 described above may be recorded on a computer-readable recording medium. The computer-readable recording medium is, for example, a flexible disk, a magneto-optical disk, a portable medium such as a ROM or a CD-ROM, or a storage device such as a hard disk built in a computer system. Each program may be transmitted over a telecommunication line.

In the above embodiment, the control device 70 controls the refrigerant distribution system 20, but the present invention is not limited to this. For example, an operator (person) may control the refrigerant distribution system 20. In this case, for example, the operator can visually obtain the measurement results of the measuring instruments 61, 62, and 63 to determine whether the first flow path 11 and the second flow path 12 are damaged. ..
The control device 70 or the operator may control the refrigerant distribution system 20 without being based on the measurement results of the measuring instruments 61, 62, 63.

In addition, it is possible to replace the components in the embodiment with well-known components as appropriate without departing from the spirit of the present invention, and the above-mentioned modifications may be appropriately combined.

Next, the pressure loss described in the above action and effect was calculated.

The basic formula for obtaining the pressure loss is the following formula (1).

In the above equation (1), ΔP is the pressure loss (MPa), ρ is the density of the fluid (1000 kg / m ^{3 in} the case of water), V is the flow velocity (m / s), and ζ is the pressure loss coefficient peculiar to the flow path. (Fixed value) is shown.

The above equation (1) is converted into a simple equation. Since the flow velocity V is proportional to the flow rate Q when the flow path diameter does not change, the above equation (1) can be converted into the following equation (2) using the flow rate Q (m ³ / min).

Since ζ, ρ, and 2 can be treated as constants in the above equation (2), the above equation (2) can be converted into the following equation (3) using the constant C.

Estimate the pressure loss using the above equation (3). The tuyere 10 and the refrigerant distribution system 20A shown in FIGS. 10 and 11 were adopted as the objects of the trial calculation. In the tuyere 10 and the refrigerant distribution system 20A shown in FIGS. 10 and 11, the same components as those of the tuyere 10 and the refrigerant distribution system 20 shown in FIGS. 1 to 6 are designated by the same reference numerals, and the description thereof will be omitted. ..

The refrigerant distribution system 20A simplified in FIGS. 10 and 11 has basically the same configuration as the refrigerant distribution system 20 shown in FIGS. 1 to 6, but has a header between the pump 30 and the first pipe 41. It differs in that the pipe 45 is provided.

In the tuyere 10 and the refrigerant distribution system 20A shown in FIGS. 10 and 11, as shown in FIG. 11, when operating in the first mode as shown in FIG. 10, when switching from the first mode to the second mode, and as shown in FIG. Estimated calculation was performed for the operation in the second mode and the respective flow rates and pressure losses. As a premise of the trial calculation, the header pressure, which is the pressure of the header pipe 45, was kept constant.

The results are shown in Table 1 below.

The trial calculation result at the time of switching from the first mode to the second mode is a theoretical trial calculation result at the moment of switching from the first mode to the second mode. When actually switching, the trial calculation result of the second mode will be settled in an extremely short period of time.

Focusing on the water pressure (MPa) of the inflow port 12a of the second flow path 12 in Table 1 above, the value during operation in the second mode (0.35 MPa) is compared with the value during operation in the first mode (0.35 MPa). It can be seen that the value (0.58 MPa) is high. Therefore, it was confirmed that the pressure of the cooling water W flowing through the second flow path 12 can be increased during the operation in the second mode as compared with the operation in the first mode.

Apart from the trial calculation results in Table 1 above, the flow velocities of the inflow port 11a of the first flow path 11 and the inflow port 12a of the second flow path 12 during operation in the first mode and the flow velocities during operation in the second mode The flow velocity of the inflow port 12a of the second flow path 12 was calculated. The flow velocity of the inflow port 11a of the first flow path 11 was 14.1 m / s and the flow velocity of the inflow port 12a of the second flow path 12 was 5.4 m / s during the operation in the first mode. The flow velocity of the inflow port 12a of the second flow path 12 during the operation in the second mode was 8.3 m / s. Therefore, it was confirmed that the speed of the cooling water W flowing through the second flow path 12 can be increased during the operation in the second mode as compared with the operation in the first mode.

According to the results of this trial calculation, the flow velocities in the first flow path 11 and the second flow path 12 were 5.4 m / s, 8.3 m / s, and 14.1 m / s. In any case, it was also confirmed that the possibility of burnout occurring in each of the flow paths 11 and 12 is low.

10 tuyere (member)
10A cooling plate (member)
11 1st flow path 11a Inflow port 11b Outlet 12 2nd flow path 12a Inflow port 12b Outlet 20 Refrigerant flow system 30 Pump 41 1st pipe 42 2nd pipe 43 3rd pipe 44 4th pipe 51 1st valve 52 2 valve 53 3rd valve 54 Safety valve 61 1st measuring instrument 62 2nd measuring instrument 63 3rd measuring instrument W Cooling water (refrigerant)

Claims (12)

A method of cooling a member in which a first flow path and a second flow path in which the inlet and outlet of the refrigerant are different from each other are formed.
The member is used in a metal melting furnace in a state where the first flow path is arranged in a higher temperature environment than the second flow path.
A cooling method comprising a first mode in which the refrigerant is supplied to the first flow path and distributed, and then the refrigerant discharged from the first flow path is supplied to the second flow path and distributed. The cooling method according to claim 1, wherein in the first mode, the average flow velocity of the refrigerant in the first flow path is higher than the average flow velocity of the refrigerant in the second flow path. Further provided with a second mode in which the refrigerant is supplied to the second flow path without passing through the first flow path.
The cooling method according to claim 1 or 2, wherein when the first flow path is damaged during operation in the first mode, the first mode is switched to the second mode. The metal melting furnace is a blast furnace, the member is a tuyere, and the refrigerant is water.
The cooling method according to claim 3, wherein in the second mode, the average flow velocity of the refrigerant in the second flow path is 5 m / s or more. Further provided with a transition mode in which the flow rate of the refrigerant supplied to the second flow path without passing through the first flow path is gradually increased from the state of operating in the first mode.
During the operation in the first mode, when the outflow amount of the refrigerant from the second flow path becomes lower than the inflow amount of the refrigerant into the first flow path, the operation is performed in the transition mode and the transition is performed. The cooling method according to claim 3 or 4, wherein it is determined which of the first flow path and the second flow path is damaged based on the inflow amount and the outflow amount during operation in the mode. During the operation in the first mode, the inflow amount of the refrigerant into the first flow path, the flow amount of the refrigerant from the first flow path to the second flow path, and the flow amount of the refrigerant from the second flow path. The cooling method according to any one of claims 1 to 5, wherein it is determined which of the first flow path and the second flow path is damaged based on the outflow amount of the refrigerant. The refrigerant is a liquid
The cooling method according to any one of claims 1 to 6, wherein when the refrigerant is vaporized in the first flow path, the vaporized refrigerant is discharged from the inflow port of the first flow path. A refrigerant distribution system in which a refrigerant is circulated to a member in which a first flow path and a second flow path in which the inlet and outlet of the refrigerant are different from each other are formed.
The member is used in a metal melting furnace in a state where the first flow path is arranged in a higher temperature environment than the second flow path.
The refrigerant distribution system
A pump that delivers the refrigerant and
A first pipe connecting the pump and the inflow port of the first flow path,
A second pipe connecting the outlet of the first flow path and the inflow port of the second flow path,
A third pipe connecting the first pipe and the second pipe,
In the first pipe, the first valve provided on the downstream side of the connection portion with the third pipe and
In the second pipe, a second valve provided on the upstream side of the connection portion with the third pipe and
A refrigerant distribution system including a third valve provided in the third pipe. The refrigerant distribution system according to claim 8, wherein the average cross section of the first flow path is smaller than the average cross section of the second flow path. With the fourth pipe connected to the outlet of the second flow path,
A first measuring instrument that measures the flow rate of the refrigerant flowing through the first pipe, and
A second measuring instrument that measures the flow rate of the refrigerant flowing through the second pipe, and
The refrigerant distribution system according to claim 8 or 9, further comprising a third measuring instrument for measuring the flow rate of the refrigerant flowing through the fourth pipe. Any of claims 8 to 10, further comprising a safety valve provided in the first pipe and allowing the vaporized refrigerant to flow out from the inflow port of the first flow path when the refrigerant is vaporized in the first flow path. The refrigerant distribution system according to item 1. A control device for controlling the pump and the third valve from the first valve is further provided.
The control device is any one of claims 8 to 11, wherein the first valve and the second valve are opened, and the refrigerant is supplied from the pump to the first pipe in a state where the third valve is closed. The refrigerant distribution system described in.

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