JP2008303433A - Method for drying and preheating raw material for blast furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for drying and preheating raw materials for blast furnace without leaking the heating gas to be used for the drying of the blast furnace raw materials to the outer part, with which the drying and the preheating for blast furnace raw materials can be performed at a low cost and also, the heat quantity introduced into the furnace is reduced in the blast furnace operation and gas-flow in the furnace is made suitable by reducing the charging quantity of powdery raw materials into the blast furnace and thus, the stable operation of the blast furnace is achieved. <P>SOLUTION: The heating gas for drying and preheating the raw materials in a hopper 1 in which the raw materials for blast furnace are stored, is introduced into the hopper 1 and screening is performed when the dried and preheated raw materials are discharged from the hopper, and when the raw materials with the powdery raw materials removed therefrom are charged into the blast furnace, the inner part of the hopper is maintained to the negative pressure with respect to the outer part by discharging the gas in the hopper 1. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for drying and preheating blast furnace raw materials for drying and preheating blast furnace charging raw materials such as iron ore and coke.

  In a blast furnace, iron ore, coke, and a coagulant are used as raw materials and charged into the furnace from the top of the furnace, and high-temperature air or high-temperature air enriched with oxygen is blown into the furnace from the bottom of the furnace. Hot metal is produced by reducing and melting iron ore using heat and CO gas generated by combustion. The raw material charged from the top of the furnace is adjusted to a granularity of several mm to several tens of mm and charged into the furnace, so the combustion gas generated by the combustion of coke at the lower part of the furnace is granular filled in the furnace. The gap between the raw materials will rise toward the furnace top.

  Since heat supply to the raw material is mainly performed by heat transfer from this combustion gas, if the flow of the combustion gas in the furnace is not in an appropriate state, the temperature rise of the raw material becomes unstable, resulting in reduction or melting of iron ore. It will cause trouble.

  Therefore, in order to make the gas flow in the furnace appropriate, the furnace top charging device for charging the raw material of the appropriate particle size to the appropriate position in the furnace when the raw material in the furnace top enters the furnace. And the development of furnace top charging methods are underway.

  However, even if such a raw material charging apparatus and method are elaborated, if powder is mixed into the raw material itself, charging of the powder raw material into the furnace cannot be avoided, and the above gas flow It becomes difficult to optimize.

  The raw materials used in the blast furnace are stored in an open-air storage area called a yard once manufactured and directly sent to the blast furnace raw material tank after grain size adjustment after being manufactured in a sintering machine or coke oven. After that, this material is collected again and sent to the blast furnace raw material tank, and some iron ore is stored in the yard in granular form after it arrives at the factory. Some raw materials are sent to the raw material tank. Among these raw materials, those that are sent to the blast furnace raw material tank after being stored in the yard are inevitably wet with rainwater when stored in the yard, and the moisture content becomes several mass%. Some raw materials have a water content exceeding 10 mass%.

  In such a raw material with a large amount of water, the powder raw material adheres to the raw material particles due to water, and thus the powder raw material may not be removed even if the particle size is adjusted by a sieve or the like. Moreover, since the powder raw material containing such moisture easily adheres to the sieve net itself, it causes clogging of the sieve, and as a result, there is a problem that sieving of the raw material becomes more difficult.

  The powder raw material that could not be removed from the granular raw material by the sieve is transported to the top of the furnace while being attached to the granular raw material, and when it is inserted into the furnace, it is dried by the heat in the furnace and detached from the surface of the granular raw material. In some cases, the raw material flows in the gap between the raw materials in the furnace, and in some cases, the granular raw material accumulates in the gap between the raw materials to inhibit the gas flow in the furnace.

  Therefore, it can be said that the technique of removing the powder raw material adhering to the blast furnace raw material is as important as the raw material charging technique in the blast furnace furnace.

Conventionally, from the viewpoint of preheating the blast furnace raw material, in Patent Document 1, before weighing the blast furnace raw material, atmospheric gas or exhaust gas discharged from a blast furnace dry pit, a metallurgical heating furnace or other hot air generating source is recovered, There has been proposed a constant-humidity warm charging method for a blast furnace raw material that gives the gas calorific value to the blast furnace raw material. The purpose of this is to remove the moisture adhering to the blast furnace raw material as much as possible by heating it before weighing it, to keep the moisture in the raw material constant, and to accurately weigh the blast furnace raw material.
JP-A-53-141117

  If the technology described in Patent Document 1 is used, the blast furnace raw material can be heated and dried before charging the blast furnace, and the amount of water introduced into the blast furnace furnace is reduced, so that the blast furnace operation is input into the furnace. It is possible to reduce the amount of heat generated. However, this technology aims to reduce the moisture content by drying the blast furnace raw material and accurately measure it. The adhering powder raw material is weighed together with the granular raw material and loaded into the blast furnace furnace. Therefore, it is considered impossible to prevent clogging due to the powder raw material in the blast furnace furnace. That is, it is possible to reduce the amount of heat input into the furnace in the blast furnace operation, but it is not effective for the purpose of reducing the powder raw material charged into the furnace.

  Moreover, in the technique disclosed in Patent Document 1, it is said that blast furnace raw materials such as ore and coke can be dehumidified and dried by blowing exhaust gas into an ore reserve hopper and a coke weighing hopper. As described in FIG. 2 of Patent Document 1, when exhaust gas is blown into the hopper from below the hopper through the nozzle, hot air is blown out from the raw material inlet of the ore reserve hopper and the coke weighing hopper. Become. If operation is performed for a long time in such a state, it is necessary to prohibit entry around the hopper at all times, which makes it difficult to inspect the equipment. There is also a problem of environmental pollution due to dust generation.

  Therefore, the present invention solves such problems of the prior art, enables drying and preheating of the blast furnace raw material by an inexpensive method, reduces the amount of heat input into the furnace during blast furnace operation, and It aims at providing the drying preheating method of the blast furnace raw material which makes the gas flow in a furnace appropriate by reducing the amount of powder raw materials brought in, and achieves the stable operation of a blast furnace by this. Another object of the present invention is to provide a method for preheating drying of a blast furnace raw material without causing leakage of heated gas used for drying the blast furnace raw material to the outside.

The features of the present invention for solving such problems are as follows.
(1) A heating gas for drying and preheating the raw material in the hopper is introduced into the hopper for storing the raw material of the blast furnace, and sieving is performed when discharging the dried and preheated raw material from the hopper. A method for preheating drying of a blast furnace raw material, characterized in that when the raw material from which the raw material has been removed is charged into a blast furnace, the inside of the hopper is maintained at a negative pressure with respect to the outside by exhausting the inside of the hopper.
(2) A hopper for storing the raw material of the blast furnace, a sieve facility for sieving the raw material discharged from the hopper below the hopper, an air supply device for supplying heated gas into the hopper, Use a blast furnace raw material drying preheating device that has an exhaust device that sucks gas to remove dust and a raw material inlet lid on the hopper that has a shut-off lid that can open and close the inlet and seal the hopper. The drying preheating method for a blast furnace raw material according to (1), wherein
(3) A blast furnace raw material drying and preheating device, a feeder for discharging the raw material in the hopper downward, an air supply port for supplying heating gas into the hopper on the side wall of the hopper, and an exhaust port for sucking the gas in the hopper The air supply device has an inlet-side flow control valve that adjusts the supply amount of the heated gas to the air supply port, and the exhaust device sucks in the gas in the hopper, a suction fan, a dust collector, and a suction from the exhaust port A drying preheating method for a blast furnace raw material according to (2), further comprising an outlet side flow rate adjusting valve for adjusting a gas flow rate.
(4) The blast furnace raw material drying preheating method according to any one of (1) to (3), wherein the blast furnace raw material has a plurality of hoppers for storing the blast furnace raw material.

  According to the present invention, it is easy to remove moisture from the blast furnace raw material, and it is possible to reliably remove the powder raw material by sieving, and to prevent the wet powder raw material from adhering to the sieve and causing clogging of the sieve. Therefore, there is an effect that the management of the sieve becomes easy.

  As a result, the amount of heat input into the blast furnace can be reduced, and the amount of powder raw material brought into the blast furnace is reduced, so that the gas flow in the furnace can be optimized and greatly contribute to the stable operation of the blast furnace. it can.

  In addition, leakage of heated gas and raw material powder from a blast furnace raw material drying preheating device (hopper) can be prevented, and equipment inspection can be performed safely at all times.

  In the present invention, in order to dry and preheat the blast furnace raw material, a heating gas for drying and preheating the raw material in the hopper is introduced into the hopper for storing the raw material in the blast furnace, and the dried and preheated raw material is discharged from the hopper. When sieving, the raw material from which the powder raw material has been removed can be charged into the blast furnace. At the same time, the inside of the hopper is evacuated and the inside of the hopper is maintained at a negative pressure with respect to the outside so that the heated gas and the powder raw material do not leak outside the hopper. For this purpose, it is preferable to install a blocking lid that can be opened and closed and the hopper can be hermetically sealed at the raw material inlet at the top of the hopper. During the drying of the raw material with the shut-off lid closed, even when the raw material is supplied to the hopper with the shut-off lid open, the inside of the hopper is exhausted so that the inside of the hopper is in a negative pressure state with respect to the outside. By maintaining, leakage of heated gas and raw material powder from the raw material inlet is prevented.

  In order to carry out the drying preheating method for the blast furnace raw material described above, a hopper for storing the raw material of the blast furnace, a sieving facility for sieving the raw material discharged from the hopper below the hopper, and a feed for supplying heated gas into the hopper. A blast furnace raw material having an air device, an exhaust device that sucks and removes dust from the gas in the hopper, and a shut-off lid that can open and close the inlet and seal the hopper, which is a lid of the raw material inlet at the top of the hopper It is preferable to use a drying preheating device.

  The blast furnace raw material drying preheating device has a feeder that discharges the raw material in the hopper downward, an air supply port that supplies heated gas into the hopper side wall, and an exhaust port that sucks the gas in the hopper. The air supply device has an inlet-side flow control valve that adjusts the supply amount of heated gas to the air supply port, and the exhaust device sucks the gas in the hopper, the suction fan, the dust collector, and the flow rate of the suction gas from the exhaust port It is preferable to have an outlet side flow rate adjusting valve that adjusts the flow rate. Moreover, it is preferable that an air supply apparatus has an introduction fan which pressurizes heated gas, and has a pressure gauge which measures the pressure in a hopper in an air supply port position.

  An embodiment of the present invention using the above blast furnace raw material drying preheating apparatus will be described with reference to FIG.

  In FIG. 1, a blast furnace raw material drying preheating apparatus supplies hoppers 1 and 2 for storing blast furnace raw materials, a sieve equipment (screen) 4 for sieving raw materials discharged from the hoppers, and supplying heated gas into the hopper. It has an air supply device 8, an exhaust device 15 that sucks and removes the gas in the hopper, and a blocking lid 20 that is a lid of the raw material inlet at the top of the hopper. Furthermore, it has a feeder 3 for discharging the raw material in the hopper downward, an air supply port 11 for supplying heated gas into the hoppers 1 and 2, and an exhaust port 19 for sucking the gas in the hopper, and an air supply device 8. Has an inlet fan 9 for boosting the heating gas, and an inlet flow rate adjusting valve 14 for adjusting the supply amount of the heating gas boosted by the inlet fan 9 to the air supply port 11. A suction fan 18 for sucking the gas, a dust collector 17, and an outlet side flow rate adjusting valve 12 for adjusting the flow rate of the suction gas from the exhaust port 19. Although it is desirable to arrange one dust collector and one suction fan for each hopper, when the equipment is constituted by a plurality of hoppers and a smaller number of dust collectors and suction fans than the number of hoppers, the outlet flow rate control valve 12 is What has a fully closed function should just be used. FIG. 1 shows a case where there are one duster and one suction fan for two hoppers.

  In FIG. 1, hoppers 1 and 2 are storage tanks for storing ore supplied to the blast furnace for each ore brand and storage tanks for storing coke supplied to the blast furnace. In the storage tank, sintered ore, raw ore (ores drilled as iron ore and adjusted in particle size by sieving, or ores containing such ores in an appropriate ratio. Ordinary hopper for each ore brand ), Hoppers are divided into sub-materials (such as limestone and serpentine), and are discharged from the hoppers at a predetermined ratio and charged into the blast furnace as mixed raw materials. In the storage tank, usually the same kind of coke is stored in a plurality of hoppers and discharged simultaneously from each hopper to measure a predetermined amount. In FIG. 1, a feeder 3 is provided below the hopper 2, and the coke discharged here is conveyed by a conveyor via a screen 4 and sent to a coke weighing hopper 5. The sieved powder on the screen is collected to the powder coke hopper 7 via the powder chute 6 and is carried out of the system by the conveyor 22.

  In FIG. 1, the discharge system of the hopper 1 is omitted for the sake of simplicity, but here too, the ore discharged by the feeder below the hopper is divided into coarse particles and powder through a screen, and the coarse particles are separated by a conveyor. It is transported to the weighing hopper and the powder is collected in the fine ore hopper.

  The air supply device 8 for supplying heated gas into the hopper has an introduction fan (pressure-increasing fan) 9 for increasing the pressure of the heated gas, and an air supply pipe 10 for supplying the heated gas into the hopper. The tip of the air supply pipe forms an air supply port 11. 13 is a hot air generating source, and 14 is an inlet flow rate adjusting valve. The heated gas generated by the hot air generation source 13 is pressurized by the introduction fan 9 and supplied into the hopper from the air supply port 11 provided on the side wall of each of the hoppers 1 and 2. As shown in FIG. 1, if an inlet-side flow rate adjustment valve 14 is installed for each air supply port 11, when supplying heated gas to a plurality of hoppers 1 and 2 simultaneously with one air supply device, The air supply amount can be adjusted, which is preferable. In addition, although one air supply port 11 of each hopper is illustrated in FIG. 1, a plurality of air supply ports may be provided in each hopper. Even in such a case, it is preferable to provide an inlet-side flow rate adjusting valve for each air supply port, because it becomes easy to uniformly adjust the flow of the heated gas in the hopper.

  The exhaust device 15 that sucks and removes the gas in the hopper has a suction pipe 16 that sucks the gas in the hopper, a dust collector 17, and a suction fan 18. The suction pipe 16 is connected to a hopper at an exhaust port 19, and an outlet-side flow rate adjustment valve 12 is installed for each exhaust port 19. As the exhaust device 15, for example, a turbo fan can be used as the suction fan 18 and a bag filter can be used as the dust collector 17.

  The hoppers 1 and 2 are exhausted by a suction fan 18 through a dust collector 17 from an exhaust port 19 provided in the upper part. By doing in this way, the heated gas sent from the air inlet 11 of the hopper rises in the hopper and a gas flow discharged from the exhaust port 19 is formed, and ores in the hopper by the heated gas, Coke is easily heated and dried. Therefore, the position of the air supply port 11 for supplying the heated gas into the hopper is preferably provided at the lower part of the hopper side wall as much as possible.

  The blast furnace raw material drying preheating apparatus further includes a blocking lid 20 positioned at the raw material charging port at the top of the hoppers 1 and 2. In the conventional hoppers 1 and 2, the upper part of the hopper is usually opened to charge the raw material into the hopper. In the present invention, except when the raw material is charged into the hopper, as shown in FIG. The charging port, which is an opening for charging, is closed with the blocking lid 20. The blocking lid 20 can be opened and closed, and has a structure in which the inside of the hopper can be sealed using an O-ring or the like.

  The material in the hoppers 1 and 2 is dried with the blocking lid 20 closed. Heated gas at a flow rate necessary for drying the raw material is sucked from the air inlet 11 using the suction fan 18. The flow rate is adjusted using the outlet flow rate adjustment valve 12. During the suction of the dry gas, the inside of the hoppers 1 and 2 becomes a negative pressure with respect to the outside, and the dry gas and raw material powder inside the hopper are not scattered outside. Moreover, the raw material powder carried in the dry gas is supplemented by the dust collector 17.

  Since the raw materials in the hoppers 1 and 2 are cut out from the hopper to the weighing hopper 5 at regular intervals according to the raw material supply to the blast furnace, the raw material level in the hopper is lowered. It is necessary to supply the raw material from the conveyor on the hopper 23 with the shut-off lid 20 at the raw material charging opening being opened for the reduced amount. At this time, before opening the shut-off lid 20, the outlet flow rate adjustment valve 12 is adjusted to reduce the suction amount by the suction fan 18, and the shut-off lid 20 is opened and the raw material is discharged while continuing the suction state. Implement the supply. After the supply of the raw material is completed and the shut-off lid 20 is closed, the flow rate necessary for drying the raw material is adjusted again by the outlet flow rate adjusting valve 12 and continuously sucked by the suction fan 18. As a result, even when the shut-off lid 20 is in an open state, external air is sucked into the hoppers 1 and 2 from the open portion of the shut-off lid 20 (the raw material inlet of the hopper). A dust collector that is always maintained at a negative pressure with respect to the outside, does not cause the heated gas inside the hopper to blow out, and does not spatter the raw material powder inside the hopper and dust generated when the raw material is supplied to the hopper. Collected at 17. Therefore, it is possible to prevent the external leakage of the dry gas and the external leakage of the raw material powder in all the periods when the blocking lid 20 is in the open state, the closed state, and the raw material supply state. As shown in FIG. 1, when the number of suction fans and dust collectors is smaller than the number of hoppers for a plurality of hoppers, the shut-off lid 20 is used by using the inlet side flow rate adjusting valve 14 and the outlet side flow rate adjusting valve 12 of each hopper 1,2. When is closed, the total amount of dry gas necessary for drying the raw material is sucked by the suction fan 18. When it is necessary to supply the raw material in each hopper, the inlet side flow rate adjustment valve 14 of the hopper is closed before the blocking lid 20 is opened in each hopper, and then the outlet side of the hopper is opened. After the flow rate adjusting valve 12 is adjusted to be close to the closed state to reduce the flow rate, the shut-off lid 20 is opened, and the raw material is charged into the hopper. Thereby, even if it does not install each one suction fan and dust collector with respect to a plurality of hoppers, the inside of each hopper can always be maintained at a negative pressure, and external leakage of heated gas and raw material powder can be prevented.

  When it is necessary to introduce a larger amount of the heated gas, it is preferable to install an introduction fan 9 between the hot air generation source 13 and the inlet flow rate adjustment valve 14 upstream of each hopper. When the introduction fan 9 is used, a pressure gauge 21 is disposed in the vicinity of the air supply port 11 so that the pressure in the hopper is higher than the suction amount of the downstream suction fan 18 so that the pressure in the hopper is not positive with respect to the outside. By controlling so as not to increase the amount of dry gas introduced by the introduction fan, external leakage of the heated gas and raw material powder can be prevented. The pressure gauge 21 only needs to be able to measure the pressure inside the hopper near the air supply port 11, and can be attached to the air supply pipe 10 portion near the air supply port 11 or to the hopper main body portion.

  As the heated gas sent to the hopper, various heated gases generated in a factory can be used. In particular, exhaust gas that is discharged at a relatively low temperature of about 300 ° C. or less and difficult to recover heat can be used effectively. In the case of blast furnace storage tanks and storage tanks, a sintering machine is usually installed in the vicinity, so using the cooler exhaust gas from the sintering machine is optimal because the air supply path is short and heat dissipation is low. And particularly preferred. In addition, heating gas can be appropriately selected according to the location conditions of each factory such as blast furnace hot stove exhaust gas and rolling heating furnace exhaust gas. Of course, a combustion furnace, an electric furnace or the like may be installed for generating heated gas, and a dedicated hot air generation source may be used.

  The temperature of the heated gas only needs to be able to dry and preheat the blast furnace raw material. Therefore, the temperature of the heated gas is preferably 60 ° C. or higher, more preferably 80 ° C. or higher. However, if the temperature exceeds 300 ° C, it is necessary to install an introduction fan (pressure booster) that can handle high-temperature gas, and the heat resistance of equipment around the hopper becomes a problem, which may increase the equipment cost. Since there exists, it is preferable to set it as 300 degrees C or less. Considering the purpose of drying preheating, 200 ° C. or less is sufficient.

  Install one or more air supply and exhaust ports on the side of the hopper. In order to dry and preheat the raw material in the hopper evenly, it is preferable to arrange a plurality of air supply ports and exhaust ports in the circumferential direction of the hopper. In addition, the plurality of air supply ports and exhaust ports are preferably arranged at equal positions in the circumferential direction.

  Next, a method for controlling the flow rate of the drying gas when using the above-mentioned blast furnace raw material drying preheating apparatus will be described with reference to FIG.

  FIG. 2 shows the relationship between the opening of the shut-off lid, the inlet side flow rate adjusting valve and the outlet side flow rate adjusting valve, the pressure in the hopper (internal pressure), and the dry gas flow rate for the two hoppers (A, B). It is a graph. When drying raw materials using hoppers A and B, first the hopper A shut-off lid is opened, then the hopper B shut-off lid is opened, and finally both the hopper A and hopper B shut-off lids are opened. This is the case.

  When opening the shut-off lid of the hopper A, the inlet side flow rate adjustment valve of the hopper A is fully closed in advance, and then the opening degree of the outlet side flow rate adjustment valve is reduced to reduce the flow rate of the dry gas. Although the internal pressure of the hopper A increases, the negative pressure is maintained. In this state, the raw material is charged into the hopper. For the hopper B, the drying of the raw material is continued without changing the opening of the inlet side flow rate adjusting valve and the outlet side flow rate adjusting valve. After the charging of the raw material is completed, the shut-off lid of the hopper A is closed, and at the same time, the opening of the outlet side flow rate adjustment valve is first increased, and then the inlet side flow rate adjustment valve is opened to bring it into a steady state.

  Next, when the shut-off lid of hopper B is opened, similarly, the inlet side flow rate adjustment valve of hopper B is fully closed in advance, and the opening degree of the outlet side flow rate adjustment valve is reduced to reduce the flow rate of the dry gas. . Although the internal pressure of the hopper B increases, the negative pressure is maintained. In this state, the raw material is charged into the hopper. For hopper A, the opening of the inlet side flow rate adjustment valve and the outlet side flow rate adjustment valve is not changed. After the charging of the raw material is completed, the shutoff lid of the hopper B is closed, and at the same time, the opening degree of the outlet side flow rate adjusting valve is first increased, and then the inlet side flow rate adjusting valve is opened to make a steady state.

  When opening the shut-off lids of hoppers A and B at the same time, similarly, the inlet side flow rate adjustment valves of hoppers A and B are fully closed, and the opening degree of the outlet side flow rate adjustment valve is reduced to reduce the flow rate of the dry gas. The pressure inside the hoppers A and B is maintained at a negative pressure. After the charging of each hopper is completed, the shut-off lid is closed, and at the same time, the opening degree of the outlet side flow rate adjustment valve is first increased, and then the inlet side flow rate adjustment valve is opened to obtain a steady state.

The sinter was dried and preheated in a storage tank for storing sinter installed in a blast furnace with an internal volume of 5150 m ³ . In the sintered ore tank, the maximum moisture content of the sintered ore was about 2 mass%. A shut-off lid with a structure that can be opened and closed and gas can be sealed at the raw material inlet at the top of the storage tank, an air supply port at the bottom of the side wall, an exhaust port at the top of the side wall, a suction fan and a dust collector And the heated gas was sucked through the air supply port. A part of the cooler exhaust gas from the adjacent sintering machine was used as the heating gas. The temperature of the heated gas was 150 ° C. at the air supply port.

  By closing the shut-off lid and sucking the heated gas with the suction fan, the inside of the storage tank was always at a negative pressure, and the heated gas and sintered ore powder (raw material powder) were not scattered outside. Moreover, the raw material powder carried with heating gas was captured by the dust collector.

  On the other hand, according to the required amount in the blast furnace in the storage tank, it is cut out at a constant interval by a weighing hopper arranged in the lower part of the storage tank, and the raw material level in the storage tank is lowered. When opening the shut-off lid, the flow rate sucked by the suction fan is reduced before opening the shut-off lid, so that the amount of suction is reduced. In a continuous state, the blocking lid was opened and the sinter was charged. After the charging of the raw materials was completed and the blocking lid was closed, the flow rate necessary for drying the sintered ore was again sucked with a suction fan. As a result, even when the shut-off lid is open, external air is sucked from the open portion of the shut-off lid, so the inside of the storage tank is always maintained at a negative pressure, and the heated gas inside does not spout. In addition, the sintered ore powder inside the storage tank and the dust generated when the sintered ore was taken into the storage tank could be collected by the dust collector without scattering outside. The water content of the sintered ore could be reduced to 0 mass%.

  Next, drying and preheating of the sintered ore were performed for a plurality of (four tanks) storage tanks. In addition to the above, for each of the four storage tanks, an inlet-side flow rate control valve was disposed in the heated gas supply port portion, and an outlet-side flow rate control valve was disposed in the exhaust port portion. When the shut-off lid of each storage tank was closed, the total amount of heated gas necessary for drying the sintered ore was sucked with a suction fan. When it becomes necessary to charge sintered ore in an individual storage tank, before opening the shut-off cover of the target storage tank, close the inlet flow control valve of that storage tank, and then The outlet side flow control valve was set to a state close to closing, the amount of heated gas sucked was reduced, the blocking lid was opened, and sintered ore was charged. The inside of the storage tank is always maintained at a negative pressure, the internal heating gas does not blow out, and the sintered ore powder inside the storage tank and the dust generation when taking the sintered ore into the storage tank are external It was possible to collect with a dust collector without splashing. At 1 hour after the start of heating, the moisture of the sintered ore discharged from the storage tank was 0.5 mass% and the temperature was 85 ° C., and sufficient drying and preheating could be achieved.

  In the raw material transported to the blast furnace remaining on the sieve after passing through the sieve equipment installed in the lower part of the storage tank, the mixing ratio of the powder having a particle size of 5 mm or less was 4.3 mass% when drying and preheating were not performed. On the other hand, when drying and preheating were performed, it was 2.2 mass%, and the amount of powder mixed into the blast furnace raw material was almost halved.

Using the dried or preheated sintered ore, the blast furnace was operated at an air flow rate of 7000 m ³ (standard state) / min. As a result, the ventilation resistance in the blast furnace was reduced, and even if the air flow rate was increased by 200 m ³ (standard state) / min, the air flow amount was about the same, and the production volume could be increased.

Schematic which shows one Embodiment of this invention. The graph which shows the relationship of the opening degree of each interruption | blocking lid | cover, the inlet side flow regulating valve, and the outlet side flow regulating valve, internal pressure, and dry gas flow rate about hoppers A and B.

Explanation of symbols

1 Hopper (storage tank)
2 Hopper (reservoir tank)
3 Feeder 4 Screen 5 Weighing hopper 6 Powder chute 7 Powder coke hopper 8 Air supply device 9 Introduction fan (pressure booster)
DESCRIPTION OF SYMBOLS 10 Air supply piping 11 Air supply port 12 Outlet side flow control valve 13 Hot air generation source 14 Inlet side flow control valve 15 Exhaust device 16 Suction piping 17 Dust collector 18 Suction fan 19 Exhaust port 20 Shut-off lid 21 Pressure gauge 22 Conveyor 23 Hopper Upper conveyor 24 Flow control valve

Claims (4)

  Introduce a heating gas to dry and preheat the raw material in the hopper to store the raw material of the blast furnace, and remove the powder raw material by sieving when the dried and preheated raw material is discharged from the hopper A method for preheating drying of a blast furnace raw material, wherein when the raw material is charged into a blast furnace, the inside of the hopper is maintained at a negative pressure with respect to the outside by evacuating the inside of the hopper.   A hopper for storing the raw material of the blast furnace, a sieve facility for sieving the raw material discharged from the hopper below the hopper, an air supply device for supplying heated gas into the hopper, and suctioning the gas in the hopper And using a blast furnace raw material drying preheating device having an exhaust device for dust removal and a raw material inlet top cover that can open and close the inlet and seal the hopper. The drying preheating method of a blast furnace raw material according to claim 1.   The blast furnace raw material drying preheating apparatus has a feeder that discharges the raw material in the hopper downward, an air supply port that supplies heated gas to the hopper side wall, and an exhaust port that sucks the gas in the hopper. The air supply device has an inlet-side flow control valve that adjusts the supply amount of heated gas to the air supply port, and the exhaust device sucks the gas in the hopper, the suction fan, the dust collector, and the flow rate of the suction gas from the exhaust port A drying preheating method for a blast furnace raw material according to claim 2, further comprising an outlet-side flow rate adjusting valve for adjusting the flow rate.   The drying preheating method for a blast furnace raw material according to any one of claims 1 to 3, comprising a plurality of hoppers for storing the raw material for the blast furnace.

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