JP7230615B2 - Cooling method and refrigerant distribution system - Google Patents

Description

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

Conventionally, a tuyere described in Patent Document 1 below is known. The tuyere has a front cooling chamber and an aft cooling chamber.
A high pressure water supply is connected to the front cooling chamber. Thereby, the cooling efficiency of the front side of the tuyere exposed to high temperatures can be enhanced.
A low pressure water supply is connected to the rear cooling compartment. As a result, the rear side of the tuyere, which is not exposed to as high a temperature as the front side, is not excessively cooled, so that excessive temperature drop of the hot air passing through the tuyere can be suppressed.

JP-A-53-73404

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

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method and system capable of cooling a member with a simple structure.

In order to solve the above problems, the present invention proposes the following means.
A cooling method according to the present invention is a method for cooling a member in which a first flow path and a second flow path are formed with different coolant inlets and outlets, wherein the member includes the first flow path is used in a metal melting furnace in a state where it is placed in a higher temperature environment than the second flow path, and after the coolant is supplied to the first flow path and circulated, it is discharged from the first flow path A first mode is provided in which the coolant is supplied to the second flow path and circulated.

In the first mode, after the coolant is supplied to the first channel and circulated, the coolant discharged from the first channel is supplied to the second channel and circulated. Therefore, it is not necessary to independently supply the coolant to the first channel and the second channel, and it is sufficient to supply the coolant to the second channel through the first channel. As a result, it is possible to simplify the structure of the system for circulating the coolant through the members. In the first mode, pressure loss occurs in the refrigerant when it 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. .
For example, the present invention can be applied to a blast furnace using a once-through type tuyere (tuyere with one flow path), and a separate flow path type tuyere (tuyere with two or more flow paths, so-called parent-child tuyere, etc.). ) is effective when newly introducing For example, when newly introducing a tuyere in which the flow path is divided into the tip of the tuyere (first flow path) and the body (second flow path), it is usually necessary to increase (increase) the pump. , additional work such as laying pipes and increasing drainage capacity is required. However, in the present invention, since the refrigerant discharged from the tip portion is cascaded and supplied to the body portion, there is no need to reinforce the pump, and the piping work can be completed within a limited range. This also applies to tuyeres 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, an average flow velocity of the coolant in the first channel may be higher than an average flow velocity of the coolant in the second channel.

The member can be effectively cooled by supplying the coolant at a high speed to the first flow path arranged in a high-temperature environment.

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

In the second mode, the refrigerant is supplied to the second flow path without passing through the first flow path, and switching between the first mode and the second mode is performed. Therefore, when the first flow path is damaged during operation in the first mode, it is possible to prevent the refrigerant from being supplied to the damaged first flow path by switching the first mode to the second mode. . As a result, it becomes possible to prevent refrigerant from leaking into the metal melting furnace (for example, blast furnace) and temperature drop/cooling inside the metal melting furnace (for example, blast furnace).
In the second mode, coolant is supplied to the second channel without passing through the first channel. Therefore, for example, when the first flow path is damaged and the operation is performed only in the second flow path in the second mode, the refrigerant balances the pressure loss of the entire system, and the flow rate of the refrigerant flowing through the second flow path increases. Therefore, the flow velocity of the coolant flowing through the second flow path can be increased. In addition, pressure loss due to the first flow path does not occur in the refrigerant flowing through the second 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 coolant 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 coolant is reduced to less than 5 m/s, the possibility of burnout due to dripping of hot metal increases. Note that the lower limit of the average flow velocity of the refrigerant at which burnout occurs decreases as the pressure of the refrigerant increases. Therefore, as in the second mode, the refrigerant does not pass through the first flow path and is supplied to the second flow path without undergoing pressure loss, and the pressure of the refrigerant flowing through the second flow path is increased. is convenient from the viewpoint of burnout prevention. Note that burnout is a state just before the refrigerant boils continuously, and the heat flux at this time is called 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.

The cooling method according to the present invention further includes 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 operation in the first mode. comprising, during operation in the first mode, operating in the transition mode when an outflow amount of the refrigerant from the second flow path becomes lower than an inflow amount of the refrigerant into the first flow path; Which of the first flow path and the second flow path is damaged may be determined based on the inflow amount and the outflow amount during operation in the transition mode.

During operation in the first mode, the amount of refrigerant flowing into the first flow passage and the amount of refrigerant flowing out of the second flow passage are normally equal.
However, when the first flow path or the second flow path is damaged, refrigerant leaks from the damaged flow path, and the outflow rate becomes lower than the inflow rate. In other words, when the outflow rate becomes lower than the inflow rate, it is assumed that the first flow path or the second flow path is damaged.
In this method, when the amount of refrigerant flowing out of the second flow path becomes lower than the amount of refrigerant flowing into the first flow path during operation in the first mode, Operate in transition mode when the flow path is suspected to be broken. 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 operation in the first mode.
At this time, the flow rate of the coolant supplied to the first channel decreases, so if the first channel is damaged, the amount of coolant leaking from the entire channel decreases. Therefore, when switching from the first mode to the transition mode, the difference between the inflow amount and the outflow amount becomes smaller.
On the other hand, since the flow rate of the coolant supplied to the second channel does not decrease at this time, even if the second channel is damaged, the amount of coolant leaking from the entire channel does not decrease. Therefore, even if the first mode is switched to the transition mode, the difference between the inflow amount and the outflow amount does not decrease.
Therefore, based on the inflow amount and the outflow amount during operation in the transition mode, it is possible to determine which of the first flow path and the second flow path is damaged.

By the way, in this method, the first mode is not instantaneously switched to the second mode, but the first mode is gradually switched to the second mode through the transition mode.
Here, when the mode is instantaneously switched from the first mode to the second mode, and the first flow path is not damaged, there is a possibility that the refrigerant will be confined in the first flow path. In this case, the refrigerant enclosed in the first flow path may expand due to exposure to high temperature, and the first flow path may be damaged (even though it is not damaged).
On the other hand, in the case of gradually switching from the first mode to the second mode via the transition mode, as in this method, compared to the case of instantaneously switching from the first mode to the second mode, the above-described Therefore, there is little possibility that the first flow path will be damaged.

During 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 Which of the first channel and the second channel is damaged may be determined based on the outflow amount of the coolant.

During operation in the first mode, if normal, the inflow amount of the refrigerant into the first flow path (hereinafter simply referred to as the inflow amount) and the circulation amount of the refrigerant from the first flow path to the second flow path (hereinafter , simply referred to as the flow rate) and the outflow rate of the refrigerant from the second flow path (hereinafter simply referred to as the outflow rate) 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 circulation amount, and the outflow amount changes. That is, when at least one of the first channel and the second channel is damaged, the outflow is lower than the inflow. When only the first flow path is damaged, the inflow amount, which is the flow rate of the refrigerant before passing through the first flow path, is high, and the circulation amount, which is the flow rate of the refrigerant after passing through the first flow path, is high. Runoff is similarly low. On the other hand, when only the second flow path is damaged, the inflow amount and the circulation amount, which are the flow rates of the refrigerant before passing through the second flow path, are similarly high, and after passing through the second flow path The outflow rate, which is the flow rate of the refrigerant, becomes low.
Therefore, by comparing the inflow, circulation and outflow based on the inflow, circulation and outflow, it is possible to determine which of the first channel and the second channel is damaged. can be done.

In the cooling method according to the present invention, the coolant may be liquid, and when the coolant is vaporized in the first flow path, the vaporized coolant may flow out from the inlet of the first flow path.

According to this cooling method, even if the refrigerant evaporates and expands in a state where the refrigerant is confined 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 (a direction in which there is no inspector) without blowing out from an unexpected location such as a flange connected to the first flow path outside the furnace. , the safety of work such as inspection can be enhanced.

A refrigerant circulation system according to the present invention is a refrigerant circulation system that circulates a refrigerant through a member in which a first flow path and a second flow path having different refrigerant inlets and outlets are formed, wherein the member comprises: The first flow path is used in a metal melting furnace in a higher temperature environment than the second flow path. a first pipe connecting the inlet of the channel, a second pipe connecting the outlet of the first channel and the inlet of the second channel, and the first pipe and the second pipe A third pipe to be connected, a first valve provided on the downstream side of the connection portion with the third pipe in the first pipe, and a connection portion with the third pipe in the second pipe A second valve provided upstream and a third valve provided in the third pipe are provided.

Normally, the refrigerant distribution system can operate in the first mode. In the first mode, after the coolant is supplied to the first channel and circulated, the coolant discharged from the first channel is supplied to the second channel and circulated. 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 operation in the first mode, the first mode can be switched to the second mode. In the second mode, coolant is supplied to the second channel without passing through the first channel. At this time, the refrigerant is supplied from the pump to the first pipe with the first and second valves 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-sectional area of the first channel may be smaller than the average cross-sectional area of the second channel.

By reducing the average cross-sectional area of the first channel and the average cross-sectional area of the second channel, the average flow velocity of the coolant flowing through the first channel is made higher than the average flow velocity of the coolant flowing through the second channel. be able to.

A refrigerant distribution system according to the present invention includes a fourth pipe connected to an outlet of the second flow path, a first measuring device for measuring the flow rate of the refrigerant flowing through the first pipe, and the second pipe. The apparatus may further include a second measuring device for measuring the flow rate of the refrigerant flowing, and a third measuring device for measuring the flow rate of the refrigerant flowing through the fourth pipe.

A first measuring device, a second measuring device and a third measuring device measure the flow rates of refrigerant flowing through the first pipe, the second pipe and the fourth pipe, respectively. Therefore, these three measuring instruments measure the amount of coolant flowing into the first channel, the amount of coolant flowing from the first channel to the second channel, and the amount of coolant flowing out of the second channel. can do. By comparing these inflow amount, circulation amount, and outflow amount, it is possible to determine which of the first channel and the second channel is damaged as described above.

The refrigerant distribution system according to the present invention includes a safety valve provided in the first pipe for causing the vaporized refrigerant to flow out from the inlet of the first flow passage when the refrigerant vaporizes in the first flow passage. You may also prepare.

According to the present invention, even if the refrigerant is vaporized and expands in a state where the refrigerant is confined in the first flow path, the expanded refrigerant flows through the inlet of the first flow path, the first pipe, and the safety valve. can escape to the outside of the first channel through the Therefore, as described above, the safety of work such as inspection can be enhanced.

The refrigerant distribution system according to the present invention further includes a control device that controls the pump and the first valve to the third valve, the control device opening the first valve and the second valve, and opening the third valve. The refrigerant may be supplied from the pump to the first pipe with the valve closed.

Thereby, the refrigerant distribution system can be operated in the first mode. Therefore, for example, the operation in the first mode can be realized without operator's operation.

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

1 is a schematic configuration diagram of a tuyere and a refrigerant distribution system according to an embodiment of the present invention, showing operation in a first mode; FIG. 2 is a view of the tuyeres and refrigerant distribution system shown in FIG. 1 as viewed from outside the blast furnace; FIG. 2 is a cross-sectional view of the tuyere and refrigerant distribution system shown in FIG. 1; FIG. FIG. 4 is a schematic configuration diagram of a tuyere and a refrigerant distribution system according to an embodiment of the present invention, showing operation in a second mode; FIG. 5 is a view of the tuyeres and refrigerant distribution system shown in FIG. 4 as seen from the outside of the blast furnace; 5 is a cross-sectional view of the tuyere and refrigerant distribution system shown in FIG. 4; FIG. FIG. 7 is a flow chart illustrating a first cooling method for cooling the tuyeres shown in FIGS. 1 to 6; FIG. FIG. 7 is a flowchart illustrating a second cooling method for cooling the tuyeres shown in FIGS. 1 to 6; FIG. FIG. 10 is a cross-sectional view of a cooling plate and a coolant distribution system according to one modification of the present invention; FIG. 4 is a block diagram showing a tuyere and a refrigerant distribution system used for trial calculation of pressure loss, and showing operation in the first mode. FIG. 4 is a block diagram showing a tuyere and a refrigerant distribution system used for trial calculation of pressure loss, and showing operation in the second mode.

A refrigerant distribution system 20 and a cooling method according to an embodiment of the present invention will be described below with reference to FIGS. 1 to 8. FIG. The coolant distribution system 20 and the cooling method cool the tuyeres 10 by circulating cooling water W, which is a coolant, through the tuyeres 10 (members). Before describing the refrigerant distribution system 20 and the cooling method, the tuyere 10 will be described first.
A tuyere 10 shown in FIG. 3 is used in a blast furnace (metal melting furnace). The tuyere 10 blows gas (hot air) into the inside from the outside of the blast furnace. Hereinafter, 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 this 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 comprises two channels 11, 12, a first channel 11 and a second channel 12. As shown in FIG. In the first channel 11 and the second channel 12, inlets 11a, 12a and outlets 11b, 12b for the cooling water W (refrigerant, liquid) are different from each other. That is, the inlet 11a of the first channel 11 is different from the inlet 12a of the second channel 12, and the outlet 11b of the first channel 11 is different from the outlet 12b of the first channel. The first channel 11 and the second channel 12 are channels independent of each other. In other words, the first channel 11 and the second channel 12 have no parts in common with each other.

A portion 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 D<b>1 of the tuyere 10 more than 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 of the tuyere 10 and cools the body of the tuyere 10 . In the tuyere 10, the first flow path 11 (the flow path for cooling the tip portion) is arranged in a higher temperature environment (the front side D1, closer to the inside of the blast furnace) than the second flow path 12 (the flow path for cooling the trunk portion). used in the blast furnace The cooling water W that has flowed in from the inlet 11 a of the first flow path 11 flows out from the outlet 11 b of the first flow path 11 without flowing through the second flow path 12 . The cooling water W that has flowed in from the inlet 12 a of the second flow path 12 flows out from the outlet 12 b 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 tuyeres 10 by circulating cooling water W through the tuyeres 10 . It should be noted that the temperature of the cooling water W may be a temperature capable of cooling the tuyeres 10, and the cooling water W may be of a high temperature. The cooling water W normally flows through the channels 11 and 12 at a temperature in the range of 20 to 40.degree. The cooling water W also includes waste water that cools the tuyeres 10 and receives a certain amount of heat from the tuyeres 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, It has

As shown in FIG. 1, the pump 30 delivers cooling water W. As shown in FIG. The pump 30 delivers (transfers, pumps) cooling water W supplied to the pump 30 from a water supply source (not shown) to the tuyere 10 . The pump 30 adjusts the amount of cooling water W to be delivered. Pump 30 is an electric pump.
In the illustrated example, two (a plurality of) pumps 30 are arranged in parallel. As a result, even when 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. Furthermore, three or more pumps 30 may be provided.

The refrigerant distribution system 20 includes a first pipe 41 , a second pipe 42 , a third pipe 43 , and a fourth pipe 44 as the plurality of pipes 41 , 42 , 43 , 44 .
The first pipe 41 connects the pump 30 and the inlet 11 a of the first flow path 11 . The first pipe 41 allows the cooling water W sent from the pump 30 to flow into the first flow path 11 . In the illustrated example, the first pipe 41 includes two (plurality) branch pipes 41a extending from each of the two pumps 30, and a main pipe 41b where the two branch pipes 41a join. The main pipe 41 b is connected to the inlet 11 a 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 outlet 11 b of the first flow path 11 and the inlet 12 a of the second flow path 12 . The second pipe 42 allows 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 41 b of the first pipe 41 and the second pipe 42 . In the second mode described later, the third pipe 43 allows the cooling water W flowing through the first pipe 41 to flow through the second pipe 42 without passing through the first flow path 11 .

The fourth pipe 44 is connected to the outflow port 12b of the second channel 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 basin, a drainage tank, or the like.

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

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

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

As shown in FIG. 2 , the safety valve 54 is provided on the first pipe 41 . The safety valve 54 is provided downstream of the first valve 51 in the first pipe 41 . The safety valve 54 causes the vaporized cooling water W to flow out (release) from the inlet 11 a of the first flow path 11 when the cooling water W vaporizes in the first flow path 11 . Therefore, even if the cooling water W vaporizes and expands (boils) in a state where the cooling water W is confined in the first flow passage 11, the expanded cooling water W flows through the inlet 11a into the first flow. You can escape to the outside of the road 11. Therefore, the expanded refrigerant is discharged in a predetermined direction (a direction in which an inspector does not exist) without blowing out from an unexpected location such as a flange connected to the first flow path 11 outside the furnace. Therefore, the safety of work such as inspection can be enhanced.

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

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

The control device 70 is configured by an information processing device. The control device 70 includes, for example, a CPU (Central Processor Unit), a memory, and an auxiliary storage device connected by a bus. 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 wired or wirelessly connected. The control device 70 controls driving of the pump 30 and the first to third valves 51 to 53 . The control device 70 acquires the measurement results of the third measuring device 63 from the first measuring device 61 .

The control device 70 operates the refrigerant distribution 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 controller 70 does not execute the first mode and the second mode in parallel. The controller 70 normally operates the refrigerant distribution system 20 in the first mode. When the control device 70 determines that the first flow path 11 has been damaged during operation in the first mode, it switches the first mode to the second mode.

It should be noted that the breakage of the first flow path 11 means, for example, that a hole communicating with the first flow path 11 is formed in the tuyere 10 . In this case, the cooling water W flowing through the first flow path 11 may leak from the broken hole portion of the tuyere 10 . Similarly, the breakage of the second flow path 12 means, for example, that a hole communicating with the second flow path 12 is formed in the tuyere 10 . In this case, the cooling water W flowing through the second flow path 12 may leak from the broken hole portion of the tuyere 10 .

As shown in FIGS. 1 to 3 , in the first mode, the coolant circulation system 20 supplies and circulates the cooling water W to the first flow path 11, and then the cooling water discharged from the first flow path 11. W is supplied to and circulated in the second channel 12 . That is, in the first mode, pressure loss occurs in the cooling water W when the cooling water W flows through the first flow path 11, and the cooling water W discharged from the first flow path 11 flows through the second flow path 12. When it does, the pressure naturally drops.
At this time, the refrigerant distribution 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. 1 to 3 ), the cooling water W is supplied from the pump 30 to the first pipe 41 .

In the first mode, it is preferable that the average flow velocity of the cooling water W in the first flow path 11 is 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 a high-temperature environment (that is, the risk of breakage is high), and the tuyeres 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) The average cross-sectional area of the first channel 11 is made smaller than the average cross-sectional area of the second channel 12 .
(2) A part of the cooling water W discharged from the first flow path 11 is discharged directly to the outside of the tuyere 10 without passing through the second flow path 12, thereby cooling the first flow path 11. The flow rate of the water W is increased to increase the average flow velocity of the cooling water W in the first flow path 11 . That is, for the drainage from the first flow path 11, a route for supplying the water to the second flow path 12 and a route for draining the water without supplying it to the second flow path 12 are provided, and the cooling water flowing through the first flow path 11 By increasing the flow rate of the water W (not increasing the flow rate of the cooling water W flowing through the second flow path 12), the average flow velocity 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 coolant distribution system 20 supplies the cooling water W to the second channel 12 without passing through the first channel 11 . Therefore, when operating in the second mode and operating only in the second flow path 12 , there is no pressure loss due to the first flow path 11 in the cooling water W flowing through the second flow path 12 . Therefore, the cooling water W flowing through the second flow path 12 can be pressurized. Further, according to the second mode, the flow rate of the cooling water W flowing through the second flow path 12 is increased more than in the first mode due to the pressure loss balance, so the cooling water W flowing through the second flow path 12 is caused to flow at a high speed. can be Furthermore, the rate of increase in velocity at this time is greater as the average flow velocity in the first flow path 11 is higher than the average flow velocity in the second flow path 12 in the first mode.
At this time, the refrigerant distribution system 20 closes the first valve 51 and the second valve 52 (both valves 51 and 52 are painted black in FIGS. 4 to 6), and opens the third valve 53 ( The third valve 53 is outlined in FIGS. 4 to 6 ), and cooling water W is supplied from the pump 30 to the first pipe 41 .

In this specification, the flow velocity of the cooling water W (refrigerant) is obtained by dividing the flow rate (volumetric flow rate, such as m ³ /s) of the cooling water W (coolant) by the cross-sectional area (eg, m ² ) of the flow path. It refers to the linear flow velocity (m/s). Designing the cross-sectional area (e.g. inner diameter) of the first flow path 11 and the second flow path 12 where the same flow rate of the cooling water W (refrigerant) flows through the first flow path 11 and the second flow path 12 to obtain the desired flow rate.
The cross-sectional area may vary depending on the position within the first flow path 11 , and the cross-sectional area may vary depending on the position within the second flow path 12 . At this time, the flow velocity of the cooling water W (refrigerant) varies depending on the position within 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 flow rate of the cooling water W (refrigerant) in the average cross-sectional area of the flow path from the inlet 11a to the outlet 11b of the first flow path 11. The average flow velocity of the cooling water W (refrigerant) in the second flow path 12 is the flow rate of the cooling water W (refrigerant) from the flow rate of the second flow path 12 from the inlet 12a to the outlet 12b. Flow velocity divided by the average cross-sectional area of the channel.

In addition, 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 empirical formula (for example, Tetsu to Hagane Vol. 62, No. 9 (1976) pp. 1151-1158, Ukai et al., "Experimental Study on Tuyere Corrosion"), the cooling water W that causes burnout The flow velocity is expressed by the temperature of the cooling water W, the water pressure, the melting point of the material of the tuyere 10 and the amount of heat to the tuyere 10 . According to studies by the present inventors, the possibility of burnout occurring can be effectively reduced by setting the flow velocity of the coolant in the second flow path 12 in the second mode to 5 m/s or more.

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

Regardless of which cooling method is the first cooling method or the second cooling method, the control device 70 controls the refrigerant circulation system 20 based on the measurement results of the plurality of measuring instruments 61, 62, 63, and the tuyeres 10 to cool. Specifically, the control device 70 executes control as described below.
(1) The controller 70 causes the refrigerant distribution system 20 to operate in the first mode.
(2) The control device 70 determines whether at least one of the first channel 11 and the second channel 12 is damaged from the measurement results of the plurality of measuring devices 61, 62, and 63.
(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 circulation system 20 in the second mode.
(4-2) When it is determined that the second flow path 12 is broken, the control device 70 notifies the operator of the breakage of the second flow path 12 by means of notification means (for example, an alarm) (not shown).

Note that the control device 70 stores and executes at least one of a program for implementing the first cooling method and a program for implementing 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 circulation 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 channel 11 and the second channel 12 is damaged based on the measurement results of the first measuring device 61 to the third measuring device 63. 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 controls the inflow amount Q1 of the cooling water W into the first flow path 11 (that is, the measurement result of the first measuring device 61) and the first A flow rate 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 device 62) and an outflow amount Q3 of the cooling water W from the second flow path 12 (that is, the second 3 measurement result of the measuring device 63), and which of the first channel 11 and the second channel 12 is damaged is determined.
In the following, first, the control device 70 determines which of the first channel 11 and the second channel 12 is damaged based on the measurement results of the first measuring device 61 to the third measuring device 63. I will explain why it is possible.

During operation in the first mode as shown in FIGS. The circulation amount Q2 of the cooling water W in the second passage 12 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, changing the relationship between the inflow amount Q1, the circulation amount Q2, and the outflow amount Q3. That is, when at least one of the first channel 11 and the second channel 12 is damaged, the outflow Q3 is lower than the inflow 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 The flow rate Q2 and the outflow rate Q3, which are the flow rates of W, are reduced to the same extent. On the other hand, when only the second flow path 12 is damaged, the inflow amount Q1 and the circulation amount Q2, which are the flow rates of the cooling water W before passing through the second flow path 12, are similarly high. The outflow Q3, which is the flow rate of the cooling water W after passing through the passage 12, becomes low.
Therefore, by comparing the inflow amount Q1, the circulation amount Q2 and the outflow amount Q3 based on the inflow amount Q1, the circulation amount Q2 and the outflow amount Q3, which of the first flow path 11 and the second flow path 12 You can determine if it is damaged.

Next, the flow of the first cooling method will be described based on the flowchart shown in FIG.

First, during normal operation, the control device 70 causes the refrigerant circulation system 20 to operate 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 circulation system 20 in the first mode.
While operating the refrigerant distribution 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 channel 11 and the second channel 12 are broken, for example, at intervals of one minute.

Specifically, when making this determination, the control device 70 first receives the measurement results from the first measuring device 61 to the third measuring device 63 (S21).
Upon receiving the measurement result, the control device 70 makes a first judgment (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 broken. Specifically, in the first determination, the control device 70 determines whether or not the outflow Q3 is lower than the inflow Q1 by a certain amount. 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. can judge.

In the first determination, it is not simply determined whether the outflow Q3 is lower than the inflow Q1, but determining whether the outflow Q3 is lower than the inflow Q1 by a "fixed amount" can be performed, for example, by measuring 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 obtained by dividing the difference between the inflow Q1 and the outflow Q3 by the inflow Q1 ((Q1-Q3)/Q1) is greater than 1% can be used as the first determination criterion. However, in the first determination, it may simply be determined whether or not the outflow Q3 is lower than the inflow Q1.

If the outflow Q3 is lower than the inflow 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 judgment (S23). If 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. Mode operation is continued (S1).

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

When the distribution amount Q2 and the outflow amount Q3 are equal, 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. may be included. In this case, for example, a value of 1% of the inflow amount Q1 can be used as the slight difference. Accepting the slight difference is intended to eliminate the effects of, for example, measurement errors.

If the flow rate Q2 and the outflow rate Q3 are equal (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 circulation system 20 from the first mode to the second mode to operate the refrigerant circulation system 20 in the second mode (S3). At this time, the controller 70 controls the pump 30 and the first to third valves 51 to 53 to operate the refrigerant circulation system 20 in the second mode.

If the flow rate Q2 and the outflow rate Q3 are not equal (S23-NO), the control device 70 determines whether only the second flow path 12 is damaged, not only the first flow path 11, or , it can be determined that both the first channel 11 and the second channel 12 are damaged. Therefore, the control device 70 issues an alarm to inform the operator of the breakage of the second flow path 12, and asks the operator to temporarily stop the blast furnace and replace the tuyeres 10 (S4). In this case, for example, the operation of the entire blast furnace is stopped and the tuyeres 10 are replaced.

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

If the outflow Q3 is lower than the inflow Q1 (S52-YES), the control device 70 can determine that the second flow path 12 is damaged, and issues an alarm to notify the operator of the damage of the second flow path 12. A decision is made to temporarily suspend the blast furnace and replace the tuyeres 10 (S4). If 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 (broken hole portion) of the first flow path 11 and block the damaged portion. In this case, the cooling water W is sealed inside the first flow path 11 . In this state, the cooling water W in the first flow path 11 is vaporized, the pressure inside the first flow path 11 becomes high, and there is a risk that water vapor will blow out from the first flow path 11 . On the other hand, in this refrigerant distribution system 20, the safety valve 54 is provided in the first flow path 11, and the safety of work such as inspection can be improved.

(Second cooling method)
In the second cooling method, the control device 70 operates the refrigerant circulation 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. 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 addition, when only the second cooling method is employed, the refrigerant circulation system 20 does not need to have the second measuring device 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 device 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 device 61), the control device 70 operates the refrigerant circulation 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 operation in the first mode. The control device 70 determines which of the first flow path 11 and the second flow path 12 is broken based on the inflow amount Q1 and the outflow amount Q3 during operation in the transition mode.
In the following, first, the control device 70 determines which of the first channel 11 and the second channel 12 is damaged based on the measurement results of the first measuring device 61 and the third measuring device 63. I will explain why it is possible.

During operation in the first mode, 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 normally equal.
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 Q3 is lower than the inflow Q1, it is assumed 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 operation in the first mode, that is, , when it is presumed that the first channel 11 or the second channel 12 is broken, it operates 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 operation in the first mode.
At this time, the flow rate of the cooling water W supplied to the first flow path 11 decreases. Therefore, if the first flow path 11 is damaged, the amount of the cooling water W leaking from the entire flow path decreases. Therefore, when the first mode is switched to the transition mode, the difference between the inflow amount Q1 and the outflow amount Q3 becomes smaller.
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 when the first mode is switched to the transition mode, the difference between the inflow amount Q1 and the outflow amount Q3 does not decrease.
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 operation in the transition mode.

Next, the flow of the second cooling method will be described based on the flowchart shown in FIG. In addition, when carrying out the same method as the first cooling method, the same number is attached and the explanation is omitted.

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

Specifically, when making this determination, the control device 70 first receives the measurement results of the first measuring device 61 and the third measuring device 63 (S61).
Upon receiving the measurement result, the control device 70 makes a first judgment (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 broken. 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 Q3 is lower than the inflow Q1 by a certain amount.

If the outflow Q3 is lower than the inflow 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, after storing the difference between the inflow amount Q1 and the outflow amount Q3 as the first difference Δ1 (S63), the control device 70 proceeds to the second determination (S64). If 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. Mode operation is continued (S1).

In the second determination (S64), the control device 70 determines which of the first flow path 11 and the second flow path 12 is damaged (whether the first flow path 11 is damaged, whether the second flow path 12 is damaged). damaged or not). Specifically, in the second judgment, the controller 70 changes the opening degrees of the valves 51, 52, and 53 by a certain amount to switch the operation mode of the refrigerant circulation 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 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 judgment, the controller 70 first changes the opening degrees of the first valve 51 to the third valve 53 to operate the refrigerant circulation system 20 in the transition mode (S641). At this time, for example, 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. The control device 70 then receives the measurement results (inflow Q1 and outflow Q3) from the first measuring device 61 and the third measuring device 63 (S642). Thereafter, the control device 70 subtracts the outflow Q3 from the inflow Q1 to obtain a second difference Δ2 (S643), and determines whether the second difference Δ2 is smaller than the first difference Δ1 by a certain amount. (S644).

In the second determination, it is not simply determined whether the second difference Δ2 is smaller than the first difference Δ1, but whether the second difference Δ2 is smaller than the first difference Δ1 by a certain amount. The purpose of judging is to eliminate the influence of measurement errors, for example. 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 simply be determined whether the second difference Δ2 is smaller than the first difference Δ1.

If 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 circulation system 20 from the first mode to the second mode, and operates the refrigerant circulation system 20 in the second mode (S3). Note that the control after the operation in the second mode is the same as the first cooling method, so the explanation is omitted.
If 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 broken. The breakage of the flow path 12 is notified, and a decision to suspend the blast furnace temporarily and replace the tuyeres 10 is requested (S4).

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

In the second cooling method, the controller 70 determines in the first determination whether the outflow Q3 is lower than the inflow Q1 by a certain amount (S62). is stored as the first difference Δ1 (S63). However, the control device 70 first obtains the first difference Δ1 prior to the first determination, and in the first determination, the first difference Δ1 is less than a predetermined threshold value (for example, 0 or 0 in consideration of the measurement error). a large value).
In the second cooling method, the control device 70 makes the second determination based on the difference between the inflow Q1 and the outflow Q3 (that is, Q1-Q3 (in other words, Δ1 or Δ2)). but not limited to this. For example, the control device 70 can make the second judgment based on the ratio of the inflow Q1 and the outflow Q3 (that is, Q1/Q3).

As described above, according to the refrigerant circulation 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 circulated, the first flow path 11 The cooling water W discharged from is supplied to the second flow path 12 and circulated. Therefore, it is not necessary to independently supply the cooling water W to the first flow path 11 and the second flow path 12 , and the cooling water W can be supplied to the second flow path 12 through the first flow path 11 . As a result, the structure of the system for circulating the cooling water W through the tuyeres 10 can be simplified.

The refrigerant distribution system 20 and the cooling method according to the present embodiment can be applied, for example, to a blast furnace in which once-through tuyeres (tuyeres with one flow path) are used. It is effective when newly introducing the above tuyeres (so-called parent-child tuyeres, etc.). For example, when newly introducing 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, normally, the pump 30 Additional construction work such as reinforcement (expansion) of pipes, installation of pipes, and enhancement of drainage capacity will be 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 is cascaded and supplied to the body, there is no need to reinforce the pump 30, and the piping work is also limited. can be done with This is the same for tuyeres in which the flow path is divided into the outer side (first flow path 11) and the inner side (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 switching between the first mode and the second mode is performed. Therefore, when the first flow path 11 is damaged during 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. As a result, it becomes possible to prevent leakage of the coolant into the blast furnace and temperature drop/cooling in the blast furnace.

In the second mode, the cooling water W is supplied to the second channel 12 without passing through the first channel 11 . Therefore, for example, when the first flow path 11 is damaged and the operation is performed only in the second flow path 12 in the second mode, the cooling water W balances the pressure loss of the entire system, and the second flow path 12 is used. Since the flow rate of the flowing cooling water W increases, the flow velocity of the cooling water W flowing through the second flow path 12 can be increased. Also, the cooling water W flowing through the second flow path 12 does not experience 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 broken, 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 dripping of hot metal increases. Note that 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 does not pass through the first flow path 11 and is supplied to the second flow path 12 without undergoing pressure loss. Higher pressure is convenient from the viewpoint of burnout prevention. Burnout is a state immediately before the cooling water W boils continuously, and the heat flux at this time is called 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. up to.

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

A 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, it is also possible to apply the refrigerant distribution system 20 and the cooling method 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 those used in blast furnaces. For example, it can be applied to metal melting furnaces other than blast furnaces, such as cupola furnaces.

All or part of the functions of the control device 70 described above may be implemented using hardware such as ASIC (Application Specific Integrated Circuit), PLD (Programmable Logic Device), and FPGA (Field Programmable Gate Array). .
The program executed by the control device 70 described above may be recorded on a computer-readable recording medium. Computer-readable recording media include portable media such as flexible disks, magneto-optical disks, ROMs and CD-ROMs, and storage devices such as hard disks incorporated in computer systems. Each program may be transmitted via an electric communication line.

Although the control device 70 controls the refrigerant distribution system 20 in the above embodiment, 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 acquire the measurement results of the measuring devices 61, 62, and 63 to determine whether the first channel 11 and the second channel 12 are damaged. .
The control device 70 or an operator may control the refrigerant distribution system 20 independently of the measurement results of the measuring devices 61 , 62 and 63 .

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

Next, a trial calculation was made for the pressure loss described in the above effects.

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 for water), V is the flow velocity (m/s), and ζ is the pressure loss coefficient unique to the channel. (fixed value).

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

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

A trial calculation of the pressure loss is made using the above equation (3). The tuyeres 10 and the refrigerant distribution system 20A shown in FIGS. 10 and 11 were used for the trial calculation. In the tuyeres 10 and the refrigerant distribution system 20A shown in FIGS. 10 and 11, the same components as those of the tuyeres 10 and the refrigerant distribution system 20 shown in FIGS. .

A refrigerant distribution system 20A shown in simplified form in FIGS. 10 and 11 has basically the same configuration as the refrigerant distribution system 20 shown in FIGS. It differs in that a tube 45 is provided.

In the tuyere 10 and the refrigerant distribution system 20A shown in FIGS. 10 and 11, when operating in the first mode as shown in FIG. 10, when switching from the first mode to the second mode, A trial calculation was made for each flow rate and pressure loss during operation in the second mode. As a premise of the trial calculation, the header pressure, which is the pressure of the header pipe 45, was fixed.

The results are shown in Table 1 below.

It should be noted that the results of trial calculations at the time of switching from the first mode to the second mode are theoretical trial calculation results at the moment of switching from the first mode to the second mode. When the mode is actually switched, the trial calculation result of the second mode is settled in an extremely short period of time.

Focusing on the water pressure (MPa) at the inflow port 12a of the second flow path 12 in Table 1 above, compared to the value (0.35 MPa) during operation in the first mode, during operation in the second mode It can be seen that the value (0.58 MPa) is high. Therefore, it was confirmed that the cooling water W flowing through the second flow path 12 can be pressurized 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 velocity at the inlet 11a of the first flow path 11 and the inlet 12a of the second flow path 12 during operation in the first mode, and the flow rate at the time of operation in the second mode and the flow velocity of the inlet 12a of the second channel 12 were calculated. While the flow velocity at the inlet 11a of the first flow path 11 was 14.1 m/s and the flow velocity at the inlet 12a of the second flow path 12 was 5.4 m/s during operation in the first mode, The flow velocity at the inlet 12a of the second flow path 12 during 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 operation in the second mode as compared with operation in the first mode.

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

10 tuyere (member)
10A Cooling plate (member)
11 First channel 11a Inlet 11b Outlet 12 Second channel 12a Inlet 12b Outlet 20 Refrigerant distribution system 30 Pump 41 First pipe 42 Second pipe 43 Third pipe 44 Fourth pipe 51 First valve 52 Second 2nd valve 53 3rd valve 54 Safety valve 61 First measuring device 62 Second measuring device 63 Third measuring device W Cooling water (refrigerant)

Claims (10)

A method for cooling a member having a first flow path and a second flow path with different coolant inlets and outlets, comprising:
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 first mode in which the coolant discharged from the first channel is supplied to the second channel and circulated after the coolant is supplied to the first channel and circulated ;
a second mode in which the coolant is supplied to the second flow path without passing through the first flow path;
with
During operation in the first mode, the amount of the refrigerant supplied to the first flow path is compared with the amount of the refrigerant discharged from the first flow path, and the amount of the refrigerant discharged from the first flow path is compared. determine whether damage has occurred,
switching the first mode to the second mode when the first flow path breaks during operation in the first mode;
cooling method. 2. The cooling method according to claim 1, wherein in said first mode, the average flow velocity of said coolant in said first flow path is higher than the average flow velocity of said coolant in said second flow path. the metal melting furnace is a blast furnace, the member is a tuyere, the coolant is water,
3. The cooling method according to claim 1 , wherein in the second mode, the average flow velocity of the coolant in the second flow path is 5 m/s or more. Further comprising 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 operation 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 to the first flow path, the transition mode is operated, and the transition mode is performed. 4. The method according to any one of claims 1 to 3, 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 mode. cooling method. During 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 5. The cooling method according to any one of claims 1 to 4 , wherein which of the first channel and the second channel is damaged is determined based on the outflow amount of the coolant. the refrigerant is a liquid,
6. The cooling method according to any one of claims 1 to 5 , wherein when the coolant vaporizes in the first flow path, the vaporized coolant flows out from an inlet of the first flow path. A refrigerant flow system for circulating a refrigerant through a member having a first flow path and a second flow path having different refrigerant inlets and outlets,
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 is
a pump for delivering the refrigerant;
a first pipe connecting the pump and an inlet of the first channel;
a second pipe connecting the outlet of the first channel and the inlet of the second channel;
a third pipe connecting the first pipe and the second pipe;
A first valve provided in the first pipe downstream of a connection portion with the third pipe;
a second valve provided on the upstream side of the connection portion with the third pipe in the second pipe;
a third valve provided in the third pipe ;
a controller that controls the third valve through the pump and the first valve;
with
The control device is
Supply to the first flow path during operation in the first mode for supplying the refrigerant from the pump to the first pipe with the first valve and the second valve opened and the third valve closed comparing the amount of the refrigerant discharged and the amount of the refrigerant discharged from the first flow path to determine whether damage has occurred in the first flow path;
When it is determined that the first flow path is not damaged, the first valve and the second valve are opened, and the third valve is closed, and the refrigerant is supplied from the pump to the first pipe. death,
When it is determined that the first flow path is damaged, the first valve and the second valve are closed, and the third valve is opened, and the refrigerant is supplied from the pump to the first pipe. do,
Refrigerant distribution system. 8. The refrigerant distribution system according to claim 7, wherein the average cross-sectional area of the first flow path is smaller than the average cross-sectional area of the second flow path. a fourth pipe connected to the outlet of the second flow path;
a first measuring device for measuring the flow rate of the refrigerant flowing through the first pipe;
a second measuring device for measuring the flow rate of the refrigerant flowing through the second pipe;
9. The refrigerant distribution system according to claim 7 , further comprising a third measuring device for measuring the flow rate of said refrigerant flowing through said fourth pipe. 10. The safety valve according to any one of claims 7 to 9 , further comprising a safety valve provided in the first pipe for causing the vaporized refrigerant to flow out from the inlet of the first flow path when the refrigerant vaporizes in the first flow path. 1. The refrigerant circulation system according to 1.

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