JP4946119B2 - Drying and preheating equipment for hopper and blast furnace raw materials - Google Patents

Description

  The present invention relates to a hopper for a blast furnace charge such as iron ore and coke, and a drying preheating device, and in particular, by drying and preheating the blast furnace raw material, it is possible to avoid the charging of the powder raw material into the blast furnace and to stably operate the blast furnace It is related with the technology to plan.

  In a blast furnace, iron ore, coke, and a coagulant are 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 to burn the coke. 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.

  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 An object of the present invention is to provide a hopper and a blast furnace raw material drying preheating device that achieves an appropriate gas flow in the furnace by reducing the amount of powder raw material brought in, thereby achieving stable operation of the blast furnace.

The features of the present invention for solving such problems are as follows.
(1) A blast furnace raw material drying preheating apparatus, which has an air supply port for supplying heated gas into the hopper on the side wall of the hopper , the hopper for storing the blast furnace raw material , and the heated gas being fed into the hopper An air supply device for supplying heated gas into the hopper from a side wall of the hopper, a feeder for discharging the raw material installed below the hopper , and the exhaust discharged from the feeder forming a sieve equipment raw material sieving, pre SL gas was suction possess an exhaust device for dust in the hopper, the air tip portion of the pipe air openings by 10~30mm projects into the interior of the hopper A drying preheating apparatus for blast furnace raw material, characterized in that:
(2) air supply unit is, blast furnace according to have a booster fan for boosting the heating gas, prior Symbol dust outlet to the hopper outer portion of the extraction pipe is characterized in that it is installed (1) Raw material drying preheating equipment.
(3) The blast furnace raw material drying preheating apparatus according to (1) or (2) , wherein a plurality of air supply ports are provided in a circumferential direction of the side wall of the hopper.

  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 the present invention, the hopper for storing the raw material of the blast furnace has an air supply port for supplying heated gas into the hopper on the side wall of the hopper, and a sieve facility for sieving the raw material discharged from the hopper below the hopper Is used. Introducing a heating gas for drying and preheating the raw material in the hopper from the air supply port, and sieving the dried and preheated raw material from the hopper to remove the raw material from which the powder raw material has been removed from the blast furnace Can be charged.

  One embodiment of a drying preheating apparatus for a blast furnace raw material using the above hopper is shown in FIG.

  The blast furnace raw material drying preheating device has a hopper for storing the raw material, a feeder for discharging the raw material below the hopper, and a sieving facility for sieving the discharged raw material. And an exhaust device that sucks and removes the gas in the hopper. In FIG. 1, the storage tank 1 and the storage tank 2 correspond to the hopper which stores the raw material of the drying preheating apparatus of a blast furnace raw material. 3 is a feeder, 4 is a screen with sieve equipment, 8 is an air supply device, 15 is an exhaust device, and stores the ore to be supplied to the blast furnace for each ore brand, and a storage tank 1 and coke to be supplied to the blast furnace. The example which supplies heated gas to the storage tank 2 to perform is shown. The normal storage tank 1 and the storage tank 2 are each formed by a plurality of hoppers. In storage tank 1, sintered ore, raw ore (ores drilled as iron ore and adjusted in particle size by sieving, ores containing such ores in an appropriate ratio. The hopper is divided into sub-materials (such as limestone and serpentine materials), discharged from the hopper at a predetermined ratio, and charged into the blast furnace as a mixed raw material. In the storage tank 2, normally 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 of the storage tank 2, and the coke discharged here is conveyed by a conveyor via a screen 4 and sent to a coke weighing hopper 5. The sieving powder on the screen is collected to a powder coke hopper 7 via a powder chute 6 and carried out of the system.

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

  The air supply device 8 for supplying heated gas into the hopper has a pressure-up fan (introduction 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 protrudes 10 to 30 mm into the hopper to form an air supply port 11, and a dust discharge port 12 is installed on the hopper outside of the air supply pipe. 13 is a hot air generating source, and 14 is a flow control valve. The heated gas generated by the hot air generation source 13 is pressurized by the introduction fan 9 and is supplied into the hopper from the air supply port 11 provided on the side wall of each of the storage tank 1 and the storage tank 2. As shown in FIG. 1, when a flow control valve 14 is installed for each air supply port 11, when heating gas is supplied simultaneously to the plurality of storage tanks 1 and the storage tanks 2 with one air supply device. Each 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 this case, it is preferable to provide a flow control 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 through an exhaust port 19. An exhaust port 19 is provided in the upper part of each hopper (the storage tank 1 and the storage tank 2), and is exhausted by the suction fan 18 through the dust collector 17. 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 through which the heated gas is supplied into the hopper is preferably provided in the lower part of the hopper side wall as much as possible. In the conventional storage tank 1 and the storage tank 2, the upper portion of the hopper is normally opened to charge the raw material into the hopper. In the present invention, the suction fan 18 is used to effectively suck the heated gas. As shown in FIG. 1, it is preferable to close the opening for charging the raw material with a simple lid 20 except when the raw material is charged into the hopper. However, since the dust from the upper part of the hopper due to the heated gas rising from below by the suction fan 18 is prevented, the lid on the upper part of the hopper is not necessarily required.

  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 a booster fan (introduction fan) that can handle high-temperature gas, and the heat resistance of equipment around the hopper becomes a problem, which may increase the equipment cost. Therefore, it is preferable that the temperature is 300 ° C. or lower. Considering the purpose of drying preheating, 200 ° C. or less is sufficient.

  Install one or more air supply 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 in the circumferential direction of the hopper. The plurality of air supply ports are preferably arranged at equal positions in the circumferential direction. FIG. 2 shows another embodiment of the present invention in which a plurality of air supply ports are arranged in the circumferential direction of the hopper.

  In FIG. 2, an annular pipe 31 is provided around the hopper 30, and the heated gas is supplied to the air supply port 11 through the hot air supply pipe 10. The annular pipe 31 serves as a reservoir, and the heated gas can be supplied from each air supply port 11 evenly.

  In order to avoid backflow of blast furnace raw materials (ores and coke) to the air supply port 11, it is preferable that the tip of the air supply port protrudes into the hopper 30 by about 10 to 30 mm. Since the tip of the air supply port protrudes into the hopper 30, the raw material that has descended the inner surface of the side wall of the hopper 30 becomes difficult to enter the air supply port. However, if the protruding state exceeds 30 mm, the raw material becomes a hindrance when descending the hopper 30 and may cause shelves in the hopper 30, so the protruding length is 10 to 10 mm from the inner surface of the hopper 30. 30 mm is preferable.

  Furthermore, it is preferable to install a dust discharge port as shown at 12 in FIG. By providing the dust discharge port 12, when the air supply port 11 is clogged, the dust discharge port 12 is opened to easily release the clogging of the air supply port 11.

  Moreover, it is preferable that the angle at which the air supply pipe 10 is inserted into the hopper 30 is about 5 ° to 30 ° downward from the horizontal when the heated gas flow is directed into the hopper. Since the air supply port 11 faces downward, there is an effect in suppressing the backflow of the raw material from the air supply port 11 into the air supply pipe 10.

  The size of the air supply port 11 can be appropriately set so that the gas velocity at the air supply port 11 of the heated gas blown from the air supply port 11 into the hopper 30 is about 10 to 30 m / s. If the gas velocity is less than 10 m / s, it may be difficult to feed the heated gas to the center of the hopper 30 and the drying and heating of the raw material may not be uniform. On the other hand, when air is supplied at a speed exceeding 30 m / s, the heated gas hardly spreads around the air supply port 11, so that dry heating is likely to be non-uniform. The shape of the air supply port 11 and the air supply pipe 10 may be a single cylindrical tube, but is not limited to a cylindrical shape, and may be a square tube. If the air inlet 11 has a diameter exceeding 50 mm, ore and coke are likely to flow back into the air inlet and clog the air inlet. It is preferable to keep it. When the angle at which the air supply pipe 10 is inserted into the hopper 30 is upward from the horizontal, installation of a net or the like at the air supply port 11 is particularly effective. The meshes can be set at intervals of 3 mm, for example.

Among 20 storage tanks installed in a blast furnace with an internal volume of 5150 m ³ , 4 tanks for storing sintered ore and 4 storage tanks for storing raw ore are the same as those shown in FIGS. The raw material drying preheating equipment was installed. The capacity of the sintered ore tank is a maximum cutout amount of 70 t / H, and the capacity of the raw ore tank is a maximum cutout amount of 100 t / H.

Since the moisture of sintered ore was about 2 mass% at the maximum, in order to reduce this to 0 mass%, 40000m ³ (standard state) / H hot air was blown, and the raw ore moisture was Since it was 5 mass% at the maximum, it was set as the equipment which can blow 140000m < ³ > (standard state) / H. A part of the cooler exhaust gas of the adjacent sintering machine was used as a hot air generation source, and this was pressurized with an introduction fan and supplied to each tank as a heated gas. The temperature of the heated gas was 150 ° C. at the air inlet of each tank.

In order to confirm the effect of the present invention, while cutting each of the above-mentioned sintering tank and one raw ore tank at the maximum cutout amount, 40000 m ³ (standard state) / H, 140000 m ³ (standard state) / H sintering machine cooler exhaust gas was pressurized and blown into each tank. Four tanks were installed for each tank, and the gas velocity at each tank was 20 m / s. The superficial gas velocity in the tank was 0.4 m / s.

  The moisture and temperature at the time of charging each tank of sintered ore and raw ore were 2% by mass of sintered ore, 25 ° C., 4% by mass of raw ore, and 25 ° C., respectively. Among those discharged from the tank, the sintered ore had a moisture content of 0.5 mass% and a temperature of 85 ° C, and the raw ore had a moisture content of 0.3 mass% and a temperature of 90 ° C, and sufficient drying heating could be achieved.

  In the sintering tank and raw ore tank in which the raw material drying preheating apparatus of the present invention was not installed, as a raw material to be transported to the blast furnace remaining on the sieve after passing through the sieve equipment installed in the lower part of each tank, Although the mixing rate was 4.3 mass% for sintered ore and 3.2 mass% for raw ore, the mixing rate was 2.3% in each of the sintering tank and raw ore tank in which the raw material drying preheating apparatus of the present invention was installed. It was 2 mass% and 1.6 mass%, and the amount of powder mixed into the blast furnace raw material was almost halved.

The raw material drying preheating apparatus of the present invention was installed in the above-described four sintering tanks and four raw ore tanks, and the blast furnace operation was performed at a blowing rate of 7000 m ³ (standard state) / min. As a result, the ventilation resistance in the blast furnace decreased, 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 the drying preheating apparatus of the blast furnace raw material which concerns on this invention. Schematic which shows other one Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Storage tank 2 Storage tank 3 Feeder 4 Screen 5 Weighing hopper 6 Powder chute 7 Powder coke hopper 8 Air supply device 9 Booster fan (introduction fan)
DESCRIPTION OF SYMBOLS 10 Air supply piping 11 Air supply port 12 Dust discharge port 13 Hot air generation source 14 Flow control valve 15 Exhaust device 16 Suction piping 17 Dust collector 18 Suction fan 19 Exhaust port 20 Lid 30 Hopper 31 Annular pipe

Claims (3)

A blast furnace raw material drying preheating device,
The hopper for storing the raw material of the blast furnace, having an air supply port for supplying heated gas into the hopper on a side wall of the hopper,
An air supply device having an air supply pipe for supplying heated gas into the hopper, and supplying the heated gas into the hopper from a side wall of the hopper;
A feeder for discharging the raw material installed below the hopper;
Sieving equipment for sieving the raw material discharged from the feeder ;
Possess an exhaust device for gas dedusting by sucking before Symbol hopper,
A blast furnace raw material drying preheating apparatus characterized in that a tip portion of the air supply pipe projects 10 to 30 mm into the hopper to form an air supply port . Air supply unit has a booster fan for boosting the heating gas, the drying of the blast furnace feed according to claim 1, the dust outlet to the hopper outer portion of the front Symbol extraction pipe is characterized in that it is installed Preheating device. The blast furnace raw material drying preheating apparatus according to claim 1 or 2 , wherein a plurality of air supply ports are provided in a circumferential direction of the side wall of the hopper.

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