JP4598558B2 - Fluidized bed dryer and method for drying wet raw material by fluidized bed dryer - Google Patents

Description

  The present invention relates to a fluidized bed dryer for drying a wet raw material such as coal charged in a coke oven, and a wet raw material drying method using the fluidized bed dryer.

  In coke production, for the purpose of improving the quality of coke and improving the productivity in the coke oven, the charging coal is dried before charging the coke oven. The water content of the coke oven coal is usually about 9 to 13% before drying, but this coal is dried to 5 to 6% with a coal dryer.

  It has been known to use a fluidized bed dryer for drying coal, and Patent Document 1 introduces coke oven flue exhaust gas as a heat source and fluidized gas into a fluidized bed dryer to dry the coal. A method is disclosed.

  In a fluidized bed dryer, a wet raw material such as coal is introduced from a charging chute and a gas that passes through the gas dispersion plate by introducing a heat source / fluidized gas from below the gas dispersion plate provided on the wind box. A fluidized bed is formed on the gas dispersion plate by the upward flow. In the fluidized bed 7, the coal powder is dried, and the coal powder is adjusted to a predetermined temperature and moisture content and discharged by a discharge chute.

  However, in the fluidized bed dryer, when the fluidized bed is not in a steady state, such as at the start or end of operation, the wet raw material falls into the windbox through the gas dispersion plate, so the It is necessary to remove the wet raw material in the box.

  On the other hand, in Patent Document 2, a falling object discharge device is provided at the lower part of the wind box, and the falling object discharge device continuously discharges falling objects into the wind box. A technique for carrying out the same together is disclosed.

However, in the technique of Patent Document 2, since the undried fallen object that has fallen into the wind box is carried out together with the discharge from the discharge chute, the target moisture content may not be achieved. In addition, a continuous discharge mechanism such as a rotary seal valve is required as a falling object discharge device, which has been a factor in increasing equipment costs and running costs. Furthermore, since the wet raw material is charged into the fluidized bed dryer by the charging chute, the wet raw material adheres and accumulates inside the charging chute, particularly at the side end (corner), which causes a charging failure. May occur.
JP 2001-55582 A Japanese Patent No. 3037680

  The problem to be solved by the present invention is to reliably dry the wet raw material dropped in the wind box of the fluidized bed dryer, and to reliably achieve the target moisture content of the processed product by the fluidized bed dryer. is there.

  Another object is to prevent wet raw materials from adhering to and depositing on the charging chute of the fluidized bed dryer.

  The method for drying a wet raw material by a fluidized bed dryer according to the present invention includes a fluidized bed in a wet raw material drying method by a fluidized bed dryer that forms a fluidized bed on a gas dispersion plate on an air box and dries the wet raw material. The wet raw material that has fallen into the air box is collected and then charged again into the fluidized bed.

  Further, the fluidized bed dryer of the present invention is a fluidized bed dryer that forms a fluidized bed on a gas dispersion plate on a windbox and dries the wetted material. It is characterized in that a transport path is provided for charging the fluidized bed again after collection.

  In the present invention, the wet raw material dropped and recovered in the wind box can be transported using the pressure of the fluidized gas in the wind box below the fluidized bed. Moreover, when the pressure of the fluidized gas in the wind box below the fluidized bed is insufficient, the insufficient pressure can be compensated by a blower provided on the downstream side of the transport path.

  The transfer destination of the wet raw material can be inside or upstream of the charging chute of the fluidized bed dryer.

  When the fluidized bed dryer is provided with a plurality of wind boxes, the wet raw material dropped in each wind box can be recovered and then introduced again into the fluidized bed through the same conveyance path.

  In the present invention, the wet raw material that has fallen from the fluidized bed into the wind box is collected and then charged again into the fluidized bed. The amount of moisture can be reliably achieved.

  In addition, the continuous discharge mechanism that has been conventionally required for discharging the fallen objects into the wind box is no longer essential, and the equipment cost and running cost can be reduced.

  Furthermore, the wet raw material dropped and collected in the air box is transported by air flow using the pressure of the fluidized gas in the air box at the bottom of the fluidized bed, and the transport destination is loaded into the fluidized bed dryer. By setting the inside or upstream of the chute, it is possible to prevent the wet raw material from adhering to and depositing on the charging chute.

  Hereinafter, embodiments of the present invention will be described based on examples in which the present invention is applied to drying of coal powder for coke ovens (hereinafter simply referred to as “coal powder”).

  FIG. 1 is a schematic configuration diagram showing a first embodiment of a fluidized bed dryer according to the present invention.

  In the figure, a combustion exhaust gas (hereinafter referred to as “hot gas”) having a temperature of about 150 to 250 ° C. generated in a coke oven (not shown) is pressurized by a blower 1 and used as a heat source / fluidizing gas 2 And is introduced into the wind boxes 4a and 4b below the fluidized bed dryer 3. The high-temperature gas introduced into the wind boxes 4a and 4b rises through the gas dispersion plate 5 provided on the top of the wind boxes 4a and 4b, and is discharged from the gas outlet 6.

  Coal powder, which is a wet raw material, is charged into the fluidized bed dryer 3 by the charging chute 7 and forms a fluidized bed 8 on the gas dispersion plate 5 by the upward flow of the high temperature gas passing through the gas dispersion plate 5. The coal powder is dried in the fluidized bed 8, and the coal powder is adjusted to a predetermined temperature and moisture content and discharged by the discharge chute 9.

  A first bypass pipe 10 branches from the gas main pipe 2, and a part of the high-temperature gas is introduced into the vicinity of the gas outlet 6 in the upper part of the fluidized bed dryer 3 through the first bypass pipe 10. The hot gas introduced by the first bypass pipe 10 is for preventing the occurrence of condensation near the gas outlet 6 and downstream thereof.

  Further, a second bypass pipe 11 branches from the gas main pipe 2, and the second bypass pipe 11 communicates with the inside of the charging chute 7 via the lower ends of the air boxes 4a and 4b. Undried coal powder (falling powder) dropped from the fluidized bed 8 into the wind boxes 4a and 4b and recovered from the lower ends of the wind boxes 4a and 4b is discharged into the second bypass pipe 11. The coal powder discharged into the second bypass pipe 11 is air-flowed toward the charging chute 7 by the pressure of the fluidized gas in the wind boxes 4a, 4b below the fluidized bed 8 and the pressure of the blower 1, The fluid is recharged to the fluidized bed 8 from the incoming chute 7. That is, the second bypass pipe 11 after the lower ends of the wind boxes 4a and 4b becomes a transport path for the coal powder dropped and collected in the wind boxes 4a and 4b, and dropped and collected in the wind boxes 4a and 4b. The done coal powder is conveyed to the charging chute 7 through the same conveying path.

  The coal powder conveyed to the charging chute 7 by the second bypass pipe 11 can be blown into the charging chute 7 by the blowing nozzle 12 as shown in FIG. 2 communicating with the second bypass pipe 11. In the blowing, in order to reliably prevent the coal powder from adhering to the charging chute 7, to the side end portion (corner portion) 7b on the sliding surface 7a side of the charging chute 7 to which the coal powder easily adheres. The position and angle of the single or plural blowing nozzles 12 are adjusted so that the blowing gas (hot gas) is hit. In addition, as shown in FIG. 3, the injection nozzle 12 is arrange | positioned in the charging device 13 provided in the upstream of the charging chute 7, and the coal conveyed by the 2nd bypass pipe 11 from the upstream of the charging chute 7 is shown. Powder can also be blown in.

  FIG. 4 shows a configuration example of a discharge mechanism that discharges coal powder dropped and collected from the fluidized bed into the wind boxes 4a and 4b from the lower ends of the wind boxes 4a and 4b to the second bypass pipe 11, and FIG. Is a rotary seal valve, (b) is an injection feeder, and (c) is an example using gravity drop.

  As shown to Fig.4 (a), when utilizing the rotary seal valve 14, this is provided in the lower end part of wind box 4a, 4b, and coal powder is discharged | emitted continuously.

  As shown in FIG. 4 (b), when the injection feeder 15 is used, positive pressure (300 to 1000 mmAq) is also applied in the wind boxes 4a and 4b, so that the powder (coal powder) is surely obtained. The diameter and shape of the powder supply unit 15a and the shape of the carrier gas nozzle 15b are determined so that the powder can be discharged and conveyed.

  As shown in FIG. 4 (c), when the gravity drop method is adopted, a nozzle (orifice) 16b is provided on the downstream side of the powder supply unit 16a, and the flow rate of the carrier gas is increased so that the powder ( Good discharge and transport of coal powder). In this case as well, since the positive pressure (300 to 1000 mmAq) is applied in the wind boxes 4a and 4b, the powder supply unit 16a can be surely discharged and transported. The diameter, shape, and shape of the nozzle (orifice) 15b are determined.

  As described above, in the present invention, the wet raw material dropped from the fluidized bed 8 into the wind boxes 4a and 4b is collected and then charged again into the fluidized bed 8, so that the wet raw material discharged without sufficient drying ( Coal powder) is eliminated, and the target moisture content of the processed product by the fluidized bed dryer 3 can be reliably achieved. In addition, in this embodiment, since a part of the high-temperature gas serving as a heat source of the fluidized bed dryer 3 is used as the gas for conveying the coal powder that has fallen into the wind boxes 4a and 4b and collected, the dew condensation occurs. For prevention, it is possible to reduce the diameter of the first bypass pipe 10 that introduces the high-temperature gas in the vicinity of the gas outlet 6 in the upper part of the fluidized bed dryer 3 or to delete the first bypass pipe 10. Moreover, the coal powder can be transported to the inside or the upstream side of the charging chute 7 so that the coal powder can be prevented from adhering or accumulating inside the charging chute 7.

  FIG. 5 is a schematic block diagram showing a second embodiment of the fluidized bed dryer of the present invention. In addition, the same code | symbol is attached | subjected to the structure same as 1st Example shown in FIG. 1, and the description is abbreviate | omitted.

  In the present embodiment, a blower 17 is provided in the second bypass pipe 11 in addition to the configuration of the first embodiment, and the blower 1 provided in the gas main pipe 2 when the coal powder is conveyed in the second bypass pipe 11. When the pressure is insufficient only by the pressure of the fluidized gas in the wind boxes 4a and 4b below the fluidized bed 8, the insufficient pressure is compensated by the blower 17 of the second bypass pipe 11.

  FIG. 6 is a schematic configuration diagram showing a third embodiment of the fluidized bed dryer of the present invention. In addition, the same code | symbol is attached | subjected to the structure same as 1st Example shown in FIG. 1, and the description is abbreviate | omitted.

  In the first embodiment, the coal powder is transported to the charging chute 7 by the second bypass pipe 11, but in this embodiment, the coal powder is directly transported into the first drying chamber 3a of the fluidized bed dryer 3 and flows. The layer 8 is recharged. Also in this embodiment, a blower can be provided in the second bypass pipe 11 as in the second embodiment.

  FIG. 7 is a schematic configuration diagram showing a fourth embodiment of the fluidized bed dryer of the present invention. In addition, the same code | symbol is attached | subjected to the structure same as 1st Example shown in FIG. 1, and the description is abbreviate | omitted.

  In the first embodiment, the coal powder is conveyed to the charging chute 7 by the second bypass pipe 11, but in the present embodiment, the coal powder is directly conveyed into the second drying chamber 3b of the fluidized bed dryer 3 and is flowed. The layer 8 is recharged. In this case, as shown in FIG. 7, after the coal powder is taken in from the lower end of the air box 4a on the first drying chamber 3a side through the second bypass pipe 11 from the first drying chamber 3a side, the second drying chamber It is efficient on piping that coal powder is taken in from the lower end of the air box 4b on the 3b side and conveyed to the second drying chamber 3b. Also in this embodiment, a blower can be provided in the second bypass pipe 11 as in the second embodiment.

  FIG. 8 is a schematic configuration diagram showing a fifth embodiment of the fluidized bed dryer of the present invention. In addition, the same code | symbol is attached | subjected to the structure same as 1st Example shown in FIG. 1, and the description is abbreviate | omitted.

  In the present embodiment, the second bypass pipe 11 is branched into two, and the coal powder dropped from the first drying chamber 3a side enters the first drying chamber 3a (charging chute 7) from the second drying chamber 3b side. The dropped coal powder is conveyed to the second drying chamber 3b.

  When the fluidized bed dryer 3 has a plurality of drying chambers and wind boxes, since the properties such as the degree of drying of the coal powder from the respective drying chambers are different, the second bypass pipe is branched as in this embodiment, In some cases, it is preferable to transport the coal powder in an arbitrary wind box to an arbitrary location and re-inject it into the fluidized bed 8. In the present embodiment, a blower can be provided on the proximal end side of the second bypass pipe 11 as in the second embodiment.

  FIG. 9 is a schematic configuration diagram showing a sixth embodiment of the fluidized bed dryer of the present invention. In addition, the same code | symbol is attached | subjected to the structure same as 1st Example shown in FIG. 1, and the description is abbreviate | omitted.

  In this embodiment, only the pressure of the fluidized gas in the wind boxes 4a and 4b below the fluidized bed 8 is used, and the coal powder dropped and recovered in the windboxes 4a and 4b is returned to the fluidized bed 8 again. In FIG. 9, the coal powder that has fallen into the wind box 4a and recovered is transported into the charging chute 7 through the first transport path 18, and dropped into the wind box 4b and recovered. The coal powder is transported into the second drying chamber 3b by the second transport path 19. When the coal powder can be conveyed only by the pressure of the fluidized gas in the wind boxes 4a and 4b in the lower part of the fluidized bed 8, the second bypass pipe in the previous examples can be obtained by using the present example. It becomes unnecessary and the configuration becomes simple.

  FIG. 10 is a schematic configuration diagram showing another embodiment of a transport mechanism that transports the coal powder dropped and collected into the wind box of the fluidized bed dryer toward the fluidized bed.

  In the embodiment so far, it is conveyed by air flow conveyance, but may be conveyed by the conveyor 20 as in this embodiment.

  The present invention can be applied not only to drying coal powder to be fed into a coke oven, but also to drying other wet raw materials such as granulated slag and limestone. Further, the high-temperature gas used as the heat source and fluidizing gas of the fluidized bed dryer is not limited to the combustion exhaust gas from the coke oven, but exhaust gas from a combustion furnace or kiln can also be used.

It is a schematic block diagram which shows 1st Example of the fluidized bed dryer of this invention. In the configuration of the first embodiment, an arrangement example of blowing nozzles for re-injecting coal powder into the charging chute is shown. In the configuration of the first embodiment, an arrangement example of blowing nozzles for recharging coal powder from the upstream side of the charging chute is shown. The structure of 1st Example WHEREIN: The structural example of the discharge mechanism which discharges | emits the coal powder which fell from the fluidized bed into the windbox and was collect | recovered from a windbox is shown, (a) is a rotary seal valve, (b) is Inse. (C) shows an example using gravity drop. It is a schematic block diagram which shows 2nd Example of the fluidized bed dryer of this invention. It is a schematic block diagram which shows 3rd Example of the fluidized bed dryer of this invention. It is a schematic block diagram which shows 4th Example of the fluidized bed dryer of this invention. It is a schematic block diagram which shows 5th Example of the fluidized bed dryer of this invention. It is a schematic block diagram which shows 6th Example of the fluidized bed dryer of this invention. It is a schematic block diagram which shows the other Example of the conveyance mechanism which conveys the coal powder which fell to the wind box of the fluidized bed dryer, and was collect | recovered toward a fluidized bed.

Explanation of symbols

1 Blower 2 Gas Main 3 Fluidized Bed Dryer 3a First Drying Chamber 3b Second Drying Chamber 4a, 4b Air Box 5 Gas Dispersion Plate 6 Gas Outlet 7 Charge Chute 8 Fluidized Bed 9 Discharge Chute 10 First Bypass Pipe 11 First 2 Bypass pipe 12 Blowing nozzle 13 Charging device 14 Rotary seal valve 15 Injection feeder 15a, 16a Powder supply part 15b, 16b Nozzle (orifice)
17 Blower 18 First transport path 19 Second transport path 20 Conveyor

Claims (10)

  In a drying method of wet raw material by a fluidized bed dryer, which forms a fluidized bed on a gas dispersion plate above the wind box and charges the wet raw material such as coal charged in the coke oven, it falls into the wind box from the fluidized bed A method for drying a wet raw material using a fluidized bed dryer, wherein the wet raw material is collected and then charged again into the fluidized bed.   The fluidized-bed drying according to claim 1, wherein after collecting the wet raw material that has fallen into the wind chamber from the fluidized bed, the fluidized gas is again fed into the fluidized bed by airflow conveyance using the pressure of the fluidized gas in the windbox below the fluidized bed. Drying wet raw materials with a machine.   The method for drying a wet raw material by a fluidized bed dryer according to claim 2, wherein when the pressure of the fluidized gas in the wind box below the fluidized bed is insufficient, the insufficient pressure is compensated by a blower provided on the downstream side of the conveying path.   The wet raw material by the fluidized bed dryer according to any one of claims 1 to 3, wherein the wet raw material dropped into the air box from the fluidized bed is recovered and then charged again from the inside or upstream of the charging chute of the fluidized bed dryer. Drying method.   The fluidized bed dryer includes a plurality of air boxes, and after collecting the wet raw material that has fallen into each air box, the fluidized bed dryer is charged again into the fluidized bed through the same conveyance path. A method for drying wet raw materials using a fluidized bed dryer.   In a fluidized bed dryer that dries a wet material such as coal that is charged into a coke oven by forming a fluidized bed on the gas dispersion plate above the windbox, after collecting the wet material that has fallen into the windbox from the fluidized bed A fluidized bed dryer, characterized in that a transport path is provided for charging the fluidized bed again.   The fluidized bed dryer according to claim 6, wherein the wet raw material is conveyed in the conveyance path by utilizing the pressure of the fluidized gas in the wind box below the fluidized bed.   The fluidized bed dryer according to claim 7, wherein a blower is provided on the downstream side of the conveying path to compensate for the pressure that is insufficient when the pressure of the fluidized gas in the wind box below the fluidized bed is insufficient.   The fluidized bed dryer according to any one of claims 6 to 8, wherein a transport destination of the wet raw material by the transport path is inside or upstream of the charging chute of the fluidized bed dryer.   The fluidized bed dryer according to any one of claims 6 to 9, wherein the fluidized bed dryer includes a plurality of wind boxes, and the wet raw material dropped in each wind box is received in the same transport path. .

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