JP2909367B2 - Ladle drying and heating method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for drying and heating a ladle. More specifically, the present invention relates to a method for drying and heating a refractory lining of a ladle receiving hot metal and steel.

[0002]

2. Description of the Related Art In an indirect steelmaking method in which steel is manufactured in two steps of ironmaking and steelmaking, the molten iron taken out of a blast furnace is transported to a converter and the molten steel taken out of the converter is continuously cast. The ladle used to transport the equipment to the tundish or ingot casting mold should be lined with refractory before receiving hot metal or molten steel in the procedure shown in Fig. 8 to prevent heat cracks and the like. It is necessary to keep the temperature of the hot metal or steel evenly close to the temperature. Also, for this ladle,
When the refractory lining is changed or repaired, drying is performed for the purpose of dehydrating and drying the refractory lining.

A conventional ladle drying and heating method is shown in FIG.
As shown in FIG. 9, the mouth 102 of the ladle 101 is closed with a lid 104 provided with a burner 103, the burner 103 is fired at the mouth 102 of the ladle 101, and the combustion gas 105 is transferred to the space 106 inside the ladle. The air is exhausted from the exhaust port 107 provided in the lid 104 while being ejected.

[0004] As shown in FIG. 10, a ladle inner space 106 is opened from the center of a lid 204 that closes a mouth 102 of a ladle 101.
Long burner 203 and ladle 1 of combustion gas 205
A drying system has been proposed in which the gas is blown out toward the bottom 108 of the fuel tank 01 and exhausted from an exhaust port 207 provided in the lid 204. In the case of this drying system, the combustion gas 205 collides with the bottom 108 of the ladle 101 and then reverses and rises along the wall surface 110 of the ladle 101.
8 and the wall 110 are warmed uniformly. In order to reduce exhaust loss (loss due to sensible heat of exhaust gas exhausted) in this drying method, a recuperator (not shown) is attached to the exhaust port 207 and indirect heat exchange is performed between exhaust gas and combustion air. One that performs waste heat recovery has also been proposed.

[0005]

However, since the size of the ladle is typical and is about 4 m in inside diameter × 4.5 m in height (amount of molten metal 250 t), as shown in FIG. Even if the burner 103 is fired at the mouth 102 of the ladle 101, uniform heating is difficult, and particularly, there is a problem that the bottom 108 and the corner 109 around it are difficult to be heated. When the ladle 101 is warmed to some extent, the amount of combustion is reduced. At this time, however, the momentum of the flame / combustion gas 105 decreases and does not reach the bottom, so that there is a problem that the bottom corner 109 is further insufficiently heated.

Further, in the method of FIG. 10 in which a long burner 203 is inserted into the ladle 101 for drying, the flame is blown out near the bottom, so that the bottom 108 of the ladle 101 and the corner portion 109 of the periphery thereof are well formed. The combustion gas turns around and the bottom corner 109 is not difficult to be heated. However, according to this method, the burner 203 is exposed to the combustion gas 205, so that it can be performed in the case of drying at a relatively low temperature.
However, there is a problem of durability due to burning. Drying consists in eliminating moisture in the refractory lining of the ladle and is complete when the deepest temperature of the lining refractory begins to rise above 100 ° C. At this time, most of the temperature is between 250 ° C and 9 ° C.
Drying is performed under a relatively low temperature of 00 ° C. in the pot, and a high temperature is not required. However, in the case of heating, the ladle 101 is heated to near the temperature of hot metal or molten steel. For example, in the case of a hot metal pot, 1000-1
It is heated to 200 ° C, or 1400 to 1500 ° C in the case of a molten steel pot. For this reason, there is a risk of burning. Also, depending on the operation, it may be necessary to enrich the combustion air with oxygen to create a high-temperature flame and rapidly heat it. For example, in the case of a molten steel pot, if the drying time is short, the pot must be heated quickly, so that it is necessary to create a high-temperature flame by oxygen enrichment. In this case, the above-mentioned problem of burner burnout becomes remarkable, and the cost increase due to the use of oxygen also becomes a problem.

Further, in any of the drying and heating methods, most of the heat is wasted to the atmosphere, and the exhaust loss is large. For example, if drying is taken as an example, high heat will be thrown away for about 35 to 41 hours, and exhaust loss will reach 70%. Although it is conceivable to recover heat by attaching a recuperator, there is a problem that the heat exchange rate is low and a sufficient amount of heat cannot be collected because the space for attaching the recuperator on the lid is small.

An object of the present invention is to provide a method for drying and heating a ladle which shortens the drying time of the refractory lining of the ladle and the heating time for preheating to near the temperature of the hot metal or molten steel and reduces the energy consumption cost. With the goal.

[0009]

In order to achieve the above object, a method for drying and heating a ladle according to the present invention is characterized in that the supply of combustion air and the discharge of combustion gas are alternately performed through a regenerator. At least one or more regenerative burner systems for alternately burning a pair of burners in a short period of time with high-temperature combustion air close to the temperature of the combustion gas are provided, and protrude to near the bottom of the ladle and between the pair of burners. The ladle is closed with a lid provided with a partition wall that partially partitions the space inside the ladle, and the pair of burners are alternately burned in the ladle and the combustion gas is detoured to the bottom of the ladle over the partition wall. After the combustion, the exhaust gas is exhausted through the regenerator of the burner whose combustion is stopped, and an atmosphere in the ladle having a uniform temperature distribution is formed to dry or heat the ladle.

According to a second aspect of the present invention, there is provided a ladle drying and heating method, wherein a cylindrical core is provided at the center of the ladle and protrudes into the ladle, and the supply of combustion air and the discharge of combustion gas are performed in a honeycomb shape. A regenerative burner system in which a pair of burners are alternately burned in a short time by high-temperature combustion air close to the temperature of the combustion gas alternately performed through the heat storage body in a direction in which a swirling force is applied to the combustion gas outside the core. The ladle is closed with a lid provided with at least one or more systems with substantially no gap, the pair of burners are alternately burned in the ladle, and the combustion gas is swirled outside the core in the ladle interior space. The combustion gas is exhausted through the regenerator of the burner during which combustion is stopped, and a ladle atmosphere having a uniform temperature distribution is formed to dry or heat the ladle.

According to a third aspect of the present invention, there is provided a ladle drying and heating method, wherein the supply of combustion air and the discharge of combustion gas are alternately performed through a honeycomb-shaped regenerator to produce a high-temperature combustion gas close to the temperature of the combustion gas. At least one regenerative burner system in which a pair of burners are alternately burned by air in a short time.
At the center, a cylindrical core having a spiral fin formed on the outer peripheral surface is protruded into the ladle and installed in the center, and one of the pair of burners is arranged inside the core while the other is arranged. The burner is closed almost without gaps with a lid disposed outside the core, and the pair of burners are alternately burned in the ladle and the burned gas is discharged to the spiral fins on the outer peripheral surface of the core. The combustion gas is exhausted through the regenerator of the burner whose combustion is stopped while being swirled, and an atmosphere in the ladle having a uniform temperature distribution is formed to dry or heat the ladle.

According to a fourth aspect of the present invention, there is provided a method for drying and heating a ladle according to any one of the first to third aspects, wherein the combustion gas is introduced into the ladle in a state in which scrap is spread in the ladle in advance. I try to inject.

According to a fifth aspect of the present invention, there is provided a ladle drying and heating method, wherein the supply of combustion air and the discharge of combustion gas are alternately performed through a honeycomb-shaped regenerator, so that the combustion gas having a high temperature close to the temperature of the combustion gas is used. At least two regenerative burner systems in which a pair of burners are alternately burned by air in a short time.
The ladle is closed with almost no gap with a lid provided with more than one pair, and the pair of burners are alternately burned in the ladle, and the combustion gas is exhausted through the heat accumulator of the burner whose combustion is stopped, and a uniform temperature distribution is obtained. While forming the ladle atmosphere to dry or heat the inside of the ladle, after the ladle has been warmed to some extent, the alternate combustion of a part of the regenerative burner system is stopped to stop the combustion gas in the ladle. It is used for exhausting air and introducing outside air, and turns down while stirring the combustion gas in the ladle.

According to a sixth aspect of the present invention, there is provided a ladle drying and heating method, wherein the supply of combustion air and the discharge of combustion gas are alternately performed through a honeycomb-shaped regenerator, so that the combustion gas having a high temperature close to the temperature of the combustion gas is used. At least one regenerative burner system in which a pair of burners are alternately burned by air in a short time.
The ladle is closed almost without gaps with the lid provided with the system or more, and the pair of burners are alternately burned in the ladle, and the combustion gas is exhausted through the regenerator of the burner whose combustion is stopped. While the ladle is dried or heated by forming the atmosphere in the ladle, after the ladle has been warmed to some extent, the fuel supply amount of the regenerative burner system is not changed, and only the fuel supply amount is reduced. And turn it down.

According to a seventh aspect of the present invention, there is provided a ladle drying and heating method, wherein the supply of combustion air and the discharge of combustion gas are alternately performed through a honeycomb-shaped regenerator, so that the combustion gas having a high temperature close to the temperature of the combustion gas is used. At least one regenerative burner system in which a pair of burners are alternately burned by air in a short time.
A plurality of systems are provided, and a plurality of branched flow paths are arranged on each of the upstream side and the downstream side of the heat storage body of the heat storage type burner system, and the heat storage body is also divided into a plurality of sections corresponding to each flow path, A ladle provided with a damper that opens and closes a flow path in a part or all of the flow path on the upstream side of the heat storage body closes the ladle with almost no gap, and alternately burns the pair of burners in the ladle. The combustion gas is exhausted through the regenerator of the burner during which combustion is stopped to form an atmosphere in the ladle having a uniform temperature distribution, and the ladle is dried or heated. Turn-down is performed with an appropriate air ratio while supplying combustion air and discharging combustion exhaust gas only from the remaining flow path after closing the flow path of the section.

[0016]

Therefore, when drying or heating the refractory lining of the ladle, the mouth of the ladle is closed with a lid, and the radiant heat and combustion of the high-temperature flame obtained by the alternating combustion of the regenerative burner system mounted on this lid. Warm the refractory lining with the flow of gas. When the combustion gas after the heat exchange on the surface of the lining refractory is exhausted through the heat storage body on the burner side during which combustion is stopped, the sensible heat is recovered by the heat storage body. And
The heat recovered in the heat accumulator is used for preheating the combustion air with extremely high heat exchange efficiency by direct heat exchange and is returned to the furnace again. Since the temperature of the combustion air at this time can be set to a high temperature close to the temperature of the exhaust gas to be exhausted, the heat from the combustion of the fuel is further added thereto to obtain a high-temperature flame, thereby rapidly raising the temperature in the furnace. In addition, because they alternately burn in a short time,
The flame position changes frequently, and the temperature distribution in the pot can be made more uniform.

Further, in the case of the first aspect of the present invention, since the space inside the ladle is partitioned except for the vicinity of the bottom of the ladle by the partition wall protruding near the bottom of the ladle, combustion is performed between the pair of burners provided on the lid. The gas is evacuated through the regenerator of the burner on the opposite side by bypassing the partition wall without inviting a short path. For this reason, the combustion gas comes into contact with the entire bottom portion from the side wall in the ladle and is uniformly heated.

Further, in the case of the second aspect of the present invention, a columnar projection protruding into the ladle while the combustion gas flows from the ladle opening to the bottom and from the bottom to the opening of the ladle. Since it is swirled around the core, the atmosphere inside the furnace is agitated and spread to the wall surface side of the ladle by centrifugal force to increase the flow rate of combustion gas on the surface of the refractory lining, thereby increasing heat transfer efficiency.

Further, in the case of the third aspect of the present invention, while the combustion gas is ejected from the ladle opening to the bottom or from the core, the combustion gas is inverted at the ladle bottom and flows toward the ladle opening. The combustion gas swirls along the fins around the cylindrical core that protrudes into the pan, stirring the furnace atmosphere and spreading to the ladle wall side by centrifugal force, and the flow rate of the combustion gas on the surface of the lining refractory To increase the heat transfer efficiency.

Furthermore, in the case of the invention of claim 4, the radiant heat radiated from the refractory lining of the ladle is absorbed by the scrap by the scraps spread in advance in the ladle, and the lining heat is radiated by the radiant heat radiated from the scrap. Since the object is heated, the heating efficiency is improved.

Further, in the case of the invention of claim 5, the turndown is achieved by stopping a part of the regenerative burner system. However, the regenerative burner in which the exhaust of the combustion gas and the supply of the combustion air are stopped alternately. Since the system is continued, the atmosphere in the ladle can be agitated by high-temperature hot air while reducing the calorific value, and the combustion gas can be spread to every corner in the ladle.

Further, in the case of the invention of claim 6, after the inside of the ladle is heated to a certain temperature, the combustion of the regenerative burner system is throttled to reduce the calorific value. At this time, since the combustion air is heated to a high temperature by recovering the heat of the exhausted combustion gas, combustion can be maintained even if the fuel is throttled. Therefore, only the calorific value can be reduced without greatly changing the momentum of the combustion gas.

Further, in the case of the invention of claim 7, even if a part of the flow path on the upstream side of the regenerator is closed and the supply amount of combustion air is reduced to achieve a turn-down, the jet velocity is greatly changed. The amount of combustion can be reduced without the need. Also in this case, the combustion gas can be spread to every corner of the ladle and heated. Moreover, since the combustion gas discharged through the heat storage element is also discharged through the other flow path, the entire amount of heat of the combustion gas recovered by the heat storage element is used for preheating the combustion air.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of the present invention will be described below in detail with reference to the embodiments shown in the drawings. In the present embodiment, the structure of the ladle itself is not particularly important, and a detailed description thereof will be omitted.

FIGS. 1 to 5 are conceptual diagrams showing an example of a method for drying and heating a ladle according to the present invention. Drying or heating of the ladle is performed by closing the ladle opening with a lid equipped with a regenerative burner system and alternately burning. The regenerative burner system alternately supplies combustion air and discharges combustion gas through the regenerator, causing a pair of burners to alternately burn in a short time with high-temperature combustion air close to the temperature of the combustion gas and inject. The combustion gas is exhausted through the regenerator of the burner whose combustion is stopped, and the atmosphere in the ladle having a uniform temperature distribution is formed to dry or heat the inside of the ladle. In this embodiment, one regenerative burner system 4 is provided, but two or more systems may be provided.

Although the heat storage type burner system 4 is not particularly limited in its structure and combustion method, in this embodiment, a duct 14 containing a heat storage element 7 is connected to a burner body 13 to connect the heat storage element 7 and the burner 5. , 6 are combined so as to be alternately burned, and the exhaust gas is discharged through a stopped burner and a heat storage that are not burning. For example, as shown in FIG. 2, a combustion air supply system 8 for supplying combustion air to each of the heat storage bodies 7 of the two burners 5, 6 and a combustion gas exhaust system 9 for discharging combustion gas. Can be selectively connected through the interposition of a four-way valve 10 so that one burner 5 (or 6) is supplied with combustion air through a heat storage 7 while the other burner 6 (or 5) is supplied with a heat storage 7 It is provided so as to discharge the combustion gas through. The combustion air is supplied by, for example, a pushing fan 16 or the like, and the combustion exhaust gas is sucked from the inside of the ladle by an exhaust means such as an induction fan (not shown) and discharged to the atmosphere. Further, the fuel supply system 11 is selectively and alternately connected to one of the burners 5, 6 via a three-way valve 12, for example, to supply fuel. The fuel nozzle 15 is, for example, buried in a burner throat portion of the burner body 13 and has only an injection port opened on the inner peripheral surface of the burner throat, and is provided so as not to be exposed to the combustion gas when passing through the inside. .

The heat storage bodies 7 have a large number of honeycomb-shaped cell holes formed of a material having a large heat capacity and a high durability in spite of a relatively low pressure loss, for example, ceramics such as mullite and cordierite. The use of a cylinder is preferred. In this case, even if the gas drops below the acid dew point when recovering heat from the combustion gas, the sulfur content in the fuel and its chemically changed substances are trapped in the ceramics, and the low-temperature exhaust duct and other parts are corroded at low temperatures. I will not let you. Of course, the present invention is not particularly limited to this, and a heat storage body made of another material or structure such as a ceramic ball or a nugget may be used.

Here, the lid 3 for closing the opening 2 of the ladle 1 is provided with a device for improving the movement (stirrability) of the combustion gas in the ladle as required. For example, as shown in FIG.
Is provided with a partition wall 21 projecting to the vicinity of the ladle and partially partitioning the space in the ladle between the pair of burners 5 and 6. This partition wall 21 completely partitions the space above it except for the vicinity of the bottom 18 of the ladle 1, and the combustion gas 17 makes a short path between a pair of burners 5 and 6 arranged with the partition wall 21 interposed therebetween. Is preventing. In this case, the combustion gas 17 bypasses the partition wall 21 and is exhausted from the burner on the opposite side of the partition wall 21, so that the wall surface 20 of the ladle 1 → the bottom corner portion 19 → the bottom 18 → the bottom corner portion 19 → It flows with the wall surface 20.
Note that the partition wall 21 is integrally formed of the same refractory material as the lid 3.

Further, the combustion gas may be forcibly swirled. For example, as shown in FIG. 4, a columnar core 22 projecting into the ladle 1 may be installed at the center of the lid 3. The combustion gas 17 injected from the burners 5 and 6 outside the core 22 is installed so as to be directed in a direction in which a turning force is applied. In this case, the combustion gas injected from the burner descends along the side wall 20 of the ladle 1 due to centrifugal force to swirl around the core 22. Then, the flow reverses at the bottom, rises at the central negative pressure portion, and is extracted to the burner in which combustion is stopped. The core 22 is integrally formed of the same refractory as the lid 3. Of course, the combustion gas 17 may be swirled by attaching the pair of burners 5, 6 to the lid 3 so as to be substantially tangential to the ladle 1. In this case, the cover 3 is made cylindrical and the burners 5 and 6 are mounted in a tangential direction.
In other words, the pair of burners 5 and 6 can be attached to the flat lid 3 so that the tangential direction can be maintained slightly toward the bottom of the ladle 1.

As shown in FIG. 5, a cylindrical core 23 having a spiral fin 24 formed on the outer peripheral surface at the center of the lid 3 is formed.
May be installed so as to protrude into the ladle 1. One of the paired burners 5 is arranged inside the core 23, and the other burner 6 is arranged outside the core 23. In this case, the combustion gas 17 injected from the outside of the core 23 descends toward the bottom 18 of the ladle 1 while swirling so as to be entangled with the core 23, and the negative pressure of the core 23 at the center of the ladle 1 becomes negative. The exhaust gas is exhausted from the burner 5 in the core 23 which is drawn inward and not burned, and the waste heat is recovered by the heat storage body attached to the burner 5. When the combustion gas 17 is injected from the burner 5 inside the core 23, the combustion gas 17 is injected from the core 23 and at the same time is injected to the bottom 18 of the ladle 1, and then reverses toward the opening 2 of the ladle 1. Rise. At this time, the swirling force is given by the flow of the combustion gas 17 along the fins 24 on the outer peripheral surface of the core 23, and the swirling force rises along the wall surface 20 of the ladle 1. Then, the gas is exhausted from the burner 6.

The drying and heating of the refractory lining of the ladle 1 using the lid 3 having the heat storage type burner system 4 configured as described above are performed as follows.

First, the mouth 2 of the ladle 1 is closed with the lid 3 having the heat storage type burner system 4. Then, one of the burners constituting the regenerative burner system 4, for example, the burner 5, is burned. At the same time, the combustion gas 17 is extracted from the burner throat of the other burner 6 that has not been burned, passes through the regenerator 7, and is exhausted from the combustion gas exhaust system 9. That is, the other burner 6 is connected to the combustion gas exhaust system 9 by switching the four-way valve 10 and the fuel supply is closed by the three-way valve 12, so that combustion is not performed and the burner 6 is used as a discharge path of the combustion gas. The refractory lining of the ladle 1 is heated by the flame and the radiant heat of the combustion gas 17. Here, the combustion air supplied to the burner 5 is preheated by direct contact with the regenerator 7 and then supplied into the burner body 13 and has a high temperature (about 1000 ° C.) close to the exhaust gas temperature. Therefore, when mixed with the fuel injected from the fuel nozzle 15, even a small amount of fuel is stably burned, and a high-temperature combustion gas is obtained. Further, if sufficient fuel is injected, a high-temperature flame of about an oxygen-enriched burner or more can be easily obtained. In addition, the temperature of the combustion air changes instantaneously as the amount of combustion increases or decreases, so that the responsiveness of adjusting the temperature of the combustion gas is good. Therefore, the atmosphere temperature in the pot can be rapidly raised to a temperature suitable for drying or heating. Switching between combustion and exhaust is performed, for example, at intervals of 10 seconds to 2 minutes, preferably within about 1 minute, and most preferably 10 to 40 minutes.
It takes place at very short intervals, on the order of seconds. Further, the combustion gas discharged via the heat storage unit 7 is heated to a predetermined temperature, for example, 200 ° C.
The switching is performed when the temperature reaches about ° C. In this case, since the flame position changes frequently, the atmosphere temperature in the ladle can be made more uniform, and uneven heating can be reduced.

When the temperature in the pot reaches a temperature suitable for drying or heating the refractory lining, the combustion of the burner system 4 is reduced to such an extent that the temperature can be maintained. Here, even if the amount of combustion is reduced, it is necessary to secure the momentum of the combustion gas itself and to spread it to every corner in the ladle.

In the case of the present embodiment, a method of securing the momentum even at the time of turndown includes a plurality of, for example, a primary and a secondary at the upstream side 25 and the downstream side 26 of the regenerator 7 of the regenerative burner system 4. In addition to disposing the branched flow paths 27 and 28, the inside of the heat storage body 7 is also made to correspond to each of the flow paths 27 and 28 by a plurality of, for example, two primary and secondary sections 7a and 7b. And a portion of the heat storage body is closed. The opening and closing of the flow path and the like is performed, for example, by providing a damper for opening and closing the flow path in part or all of the flow path on the upstream side 25 of the heat storage element 7. In the case of the present embodiment, a damper 29 is provided in the secondary flow path 28. At the time of high combustion, the supply of combustion air and the exhaust of combustion gas are performed using the primary and secondary flow paths 27 and 28. However, at the time of low combustion, the air flow rate and the exhaust gas amount are reduced. 28 is closed and only the primary flow path 27 is used, so that the momentum can be secured even if the air flow rate decreases. Of course, it is also possible to control the degree of opening of the secondary flow path 28 according to the amount of turndown before the secondary flow path 28 is fully closed. According to this method, after the ladle 1 is warmed to some extent, the supply of combustion air and the combustion exhaust gas are performed only from a part of the flow path, that is, the secondary flow path 28, that is, the remaining flow path, that is, the primary flow path 27. Turn down with proper air ratio while discharging. Moreover,
In this case, since the fluid flowing through the flow paths 27 and 28 on the upstream side 25 of the heat storage element 7 is the low-temperature combustion air before preheating or the low-temperature combustion exhaust gas after passing through the heat storage element 7, the flow path 2
The damper 29 that opens and closes the opening 8 does not cause malfunction or damage due to heat.

As another method, there is a method of adjusting the combustion amount and the temperature by reducing only the fuel (excess air operation) without reducing the combustion air. This method is particularly effective in the drying step. In the drying step, it is important to discharge moisture simultaneously with uniform heating. Drying can be accelerated by increasing the amount of combustion to increase the amount of exhaust, but the usual method has a limit (m = 2) because exhaust loss increases. However, if this regenerative burner system is used, the exhaust gas temperature can be lowered, and the exhaust loss can be kept low because stable combustion is performed by the high-temperature combustion air even in the excessive air operation.

Further, as another method, a plurality of sets of regenerative burner systems 4 are prepared. During low combustion, only some of the burner systems are operated alternately. By repeating the evacuation, uniform heating by the stirring effect, ventilation effect, and improvement in heat transfer can be realized.

The above embodiment is a preferred embodiment of the present invention. However, the present invention is not limited to this embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, by injecting the combustion gas 17 into the ladle 1 in a state where the scrap 30 is spread in the ladle 1 in advance, the ladle 1 is heated and the scrap 30 radiates from the refractory lining the ladle 1 at the same time. The radiant heat generated is used for preheating the scrap, and the lining heat is heated by the radiant heat radiated from the scrap 30, so that the heating efficiency is improved.

[0038]

As is apparent from the above description, according to the ladle drying and heating method of the present invention, the pair of heat storage type burners provided on the lid for closing the ladle can be shortened. The combustion gas is exhausted through the regenerator of the burner during which combustion is stopped alternately with time, and the atmosphere inside the ladle with a uniform temperature distribution is formed to dry or heat the inside of the ladle. Even if an enrichment burner is not used, the set temperature in the furnace can be increased, the amount of heat transfer can be increased, the time required for temperature rise can be reduced, and the running cost can be reduced. In addition, since the flame position is frequently changed by alternately burning in a short time, the atmosphere temperature distribution in the pot can be made more uniform, and the heating time for eliminating uneven drying and uneven heating can be shortened. Therefore, it is possible to contribute to improvement of thermal efficiency and energy saving by exhaust heat recovery, and shorten drying time or heating time.

Further, in the case of the first aspect of the present invention, the partition wall provided in the ladle interior space prevents the exhaust of the combustion gas by the short path, and the burner is diverted so as to surely pass over the partition wall and on the other side. The exhaust gas passes through the heat storage body, so that the combustion gas surely contacts the entire bottom from the side wall in the ladle and is uniformly heated.

Further, in the case of the second and third aspects of the present invention, the combustion gas is swirled around the columnar core, so that the atmosphere in the furnace is agitated and spread to the wall surface side of the ladle by centrifugal force. To increase the heat transfer efficiency by increasing the flow rate of the combustion gas on the surface of the fuel cell.

Further, in the case of the invention of claim 4, the radiant heat radiated from the refractory lining of the ladle is absorbed by the scrap, and the lining refractory is heated by the radiant heat radiated from the scrap, so that the heating efficiency is improved. Become.

Further, in the case of the invention of claim 5, while the calorific value is reduced by partially stopping the burner system, stirring of the atmosphere in the ladle is performed by high-temperature hot air from the burner system during alternately stopped combustion. The combustion gas can be spread to every corner in the ladle.

Further, according to the invention of claim 6, since the heat of the exhausted combustion gas is recovered and the combustion air heated to a high temperature can maintain the combustion even when the fuel is throttled, only the calorific value is reduced. Even if it does, the momentum of the combustion gas does not largely change, and it is possible to uniformly heat the corners of the ladle.

Further, in the case of the invention of claim 7, even if a part of the flow path on the upstream side of the regenerator is closed and the supply amount of combustion air is reduced to achieve a turndown, the jet velocity is greatly changed. Since the amount of combustion can be reduced without using the ladle, the combustion gas can be spread all over the ladle and heated.
Moreover, since the combustion gas discharged through the heat storage element is also discharged through the remaining flow path, the entire amount of heat of the combustion gas recovered by the heat storage element is used for preheating the combustion air.

[Brief description of the drawings]

FIG. 1 is a conceptual diagram showing one embodiment of a ladle drying and heating method of the present invention.

FIG. 2 is a principle view showing an embodiment of a heat storage type burner system applied to the present invention.

FIG. 3 is a conceptual diagram showing another embodiment of the ladle drying and heating method of the present invention.

FIG. 4 is a conceptual diagram showing another embodiment of the ladle drying and heating method of the present invention.

FIG. 5 is a conceptual diagram showing still another embodiment of the ladle drying and heating method of the present invention.

FIG. 6 is a conceptual diagram showing still another embodiment of the ladle drying and heating method of the present invention.

FIG. 7 is a conceptual diagram showing a means for securing the momentum of combustion gas even when combustion is restricted in the ladle drying and heating method of the present invention.

FIG. 8 is an explanatory view showing a general ladle heating process.

FIG. 9 is a conceptual diagram showing an example of a conventional ladle drying and heating method.

FIG. 10 is a conceptual diagram showing another example of a conventional ladle drying and heating method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ladle 2 Ladle opening 3 Lid 4 Thermal storage burner system 5, 6 Burner 7 Thermal storage 17 Combustion gas 18 Ladle bottom 19 Ladle corner 20 Ladle wall 21 Partition wall 22 Columnar core 23 Cylindrical core 24 Helical fin 25 Upstream side 26 Downstream side 27 Primary flow path 28 Secondary flow path 29 Damper 30 Scrap

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI F26B 23/02 F26B 23/02 A F28D 20/00 F28D 20/00 A (72) Inventor Hiroaki Sato 1-chome Marunouchi, Chiyoda-ku, Tokyo 1-2-2 Nippon Kokan Co., Ltd. (72) Hiroshi Kurihara 1-2-1, Marunouchi, Chiyoda-ku, Tokyo 1-2-1 Nippon Kokan Co., Ltd. (72) Ryoichi Tanaka 2-1-1 Shirite, Tsurumi-ku, Yokohama, Kanagawa Prefecture No. 53 Inside Japan Furnace Industry Co., Ltd. (72) Inventor: Mamoru Matsuo 2-1-1 Shirite, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture In-house Furnace Industry Co., Ltd. No. 1-53 Japan Furnace Industry Co., Ltd. (56) References JP-A-61-60261 (JP, A) JP-A-4-251190 (JP, A) Flat 1-222102 (JP, A) (58 ) investigated the field (Int.Cl. ^6, DB name) B22D 41/015 B22D 11/10 310 F23D 14/00 F26B 23/00 F28D 20/00

Claims (7)

(57) [Claims] 1. The supply of combustion air and the discharge of combustion gas
High temperature close to the temperature of the combustion gas is performed alternately through the heat storage
Combustion air alternately burns a pair of burners in a short time
At least one regenerative burner system
The pair of bars, which are prepared above and protrude near the bottom of the ladle
With a lid that has a partition wall that partially partitions the space inside the ladle between
Close the ladle and alternate the pair of burners in the ladle
And burns the combustion gas over the partition wall
After diverting to the bottom, it passes through the heat
To create an atmosphere in the ladle with a uniform temperature distribution.
Ladle drying, characterized by drying or heating the inside of the ladle
Drying and heating method. 2. A cylindrical core projecting into the ladle at the center.
Install and store heat for supplying combustion air and discharging combustion gas
High temperature combustion close to the temperature of the combustion gas, alternating through the body
The pair of burners are alternately burned in a short time by air
Heat storage type burner system to the combustion gas outside the core
At least one system in the direction in which the turning force is applied
Close the ladle with the lid provided above, and within the ladle,
Burners alternately in the space inside the ladle
Swirl outside of the core and stop combustion.
Combustion gas is exhausted through the heat storage of
Dry or heat the ladle by forming an atmosphere inside the ladle
A method for drying and heating a ladle, comprising: 3. The supply of combustion air and the discharge of combustion gas are performed.
High temperature close to the temperature of the combustion gas is performed alternately through the heat storage
Combustion air alternately burns a pair of burners in a short time
At least one regenerative burner system
Spiral fins are formed on the outer peripheral surface at the top and at the center
Set the cylindrical core so that it protrudes into the ladle, and
When one of the pair of burners is disposed inside the core,
Ladle with lid with both other burners placed outside the core
And alternately burn the pair of burners in the ladle.
And the injected combustion gas is screwed on the outer peripheral surface of the core.
Burner heat storage during combustion stoppage swirling along swirling fins
Exhaust the combustion gas through the body and make the atmosphere in the ladle with uniform temperature distribution
Dry or heat the ladle by forming an atmosphere. Specially
Ladle drying and heating method. 4. Laying scrap in advance in a ladle
It is characterized by injecting combustion gas into the ladle
Drying of the ladle according to any one of claims 1 to 3, and
Heating method. 5. The supply of combustion air and the discharge of combustion gas
High temperature close to the temperature of the combustion gas is performed alternately through the heat storage
Combustion air alternately burns a pair of burners in a short time
At least two sets of heat storage type burner systems
Cover the ladle with the lid and replace the pair of burners in the ladle.
The burners burn each other and burner
To exhaust the combustion gases and create an atmosphere in the ladle with a uniform temperature distribution.
While forming and drying or heating the inside of the ladle,
After the heat is heated to some extent, part of the regenerative burner system
To stop the combustion of the gas in the ladle
Used to introduce outside air while stirring the combustion gas in the ladle
Drying of ladle characterized by performing turn down and
Heating method. 6. The supply of combustion air and the discharge of combustion gas
High temperature close to the temperature of the combustion gas is performed alternately through the heat storage
Combustion air alternately burns a pair of burners in a short time
At least one regenerative burner system
Close the ladle with the lid provided above, and within the ladle,
Burner alternately burns and burner during combustion stop
Exhaust the combustion gas through the body and make the atmosphere in the ladle with uniform temperature distribution
While drying or heating the inside of the ladle by forming an atmosphere,
After the ladle has been warmed to some extent, the heat storage type burner system
The fuel supply amount without changing the combustion air supply amount
The drying of the ladle is characterized by turning down
And heating method. 7. Supply of combustion air and discharge of combustion gas are performed.
High temperature close to the temperature of the combustion gas is performed alternately through the heat storage
Combustion air alternately burns a pair of burners in a short time
At least one regenerative burner system
On the upstream side of the heat storage body of the heat storage type burner system
A plurality of branched flow paths at each of the downstream and upstream sides
At the same time, the heat storage body is also divided into a plurality of sections corresponding to each flow path.
Independent and part of the flow path on the upstream side of the heat storage
Cover the ladle with a lid that has a damper that opens and closes the flow path.
And the pair of burners are alternately burned in the ladle
The combustion gas is discharged through the regenerator of the burner whose combustion is stopped.
Notice the uniform temperature distribution Form the atmosphere inside the ladle and inside the ladle
While drying or heating the ladle
After being closed, some of the flow paths are closed
Appropriate while supplying combustion air and discharging flue gas
Ladle characterized by performing turndown with the air ratio
Drying and heating method.