JP5081288B2 - 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 method for drying wet powder 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 conventionally known to use a fluidized bed dryer for drying coal. In this fluidized bed dryer, a wet raw material is charged onto a gas dispersion plate from a charging chute and a heat source is provided from the lower side of the gas dispersion plate. The fluidizing gas is blown to form a fluidized bed on the gas dispersion plate, and the wet raw material is dried in the fluidized bed (see, for example, Patent Document 1).

  However, in such a conventional fluidized bed dryer, the wet raw material to be charged is introduced into the fluidized bed on the gas dispersion plate immediately below the charging chute with the speed of dropping, so In this part, the wet raw material immediately after being put in the pores of the gas dispersion plate was clogged, causing dry failure due to poor fluidity. Further, the pores of the clogged gas dispersion plate need to be eliminated by knocking out clogs one by one when stopping and repairing the fluidized bed dryer, which takes a lot of time and labor.

Japanese Patent No. 2938029

  The problem to be solved by the present invention is to prevent clogging due to wet raw material introduced from a charging chute into a gas dispersion plate of a fluidized bed dryer.

  The present invention solves the above problem by increasing the flow rate of the heat source / fluidizing gas blown from the lower side of the gas dispersion plate immediately below the charging chute.

  The present invention is a fluidized bed in which a wet raw material is charged from a charging chute, high temperature gas is blown from the lower side of the gas dispersion plate as a heat source and fluidizing gas, a fluidized bed is formed on the gas dispersion plate, and the wet raw material is dried. When drying the wet raw material with a dryer, the heat source / fluidization flow rate of the heat source / fluidized gas blown from the lower side of the gas dispersion plate just below the charging chute is changed to the heat source / fluidization blown from the lower side of the gas dispersion plate other than directly below the charging chute. It is characterized by being faster than the gas flow rate.

  According to the present invention, since the flow rate of the heat source / fluidizing gas blown from the lower side of the gas dispersion plate immediately below the charging chute is increased, the gas distribution plate immediately below the charging chute is less likely to be clogged. Thus, clogging of the gas dispersion plate can be prevented.

The Example of the fluidized bed dryer of this invention is shown, (a) is the longitudinal cross-sectional view, (b) is the AA arrow line view of (a), (c), (d) is (a). It is a BB line arrow directional view.

  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 shows an embodiment of a fluidized bed dryer according to the present invention, in which (a) is a longitudinal sectional view, (b) is an AA arrow view of (a), (c), (d) are It is a BB line arrow directional view of (a).

  In FIG. 1, 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 boosted by a blower 1 and used as a heat source and fluidizing gas. And it introduce | transduces in the wind boxes 4a and 4b of the lower part of the fluidized bed dryer 3 through the 2nd bypass pipe 12 mentioned later. 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. The inside of the fluidized bed dryer 3 is divided into two drying chambers 3a and 3b by a partition wall 7, and wind boxes 4a and 4b are arranged below the respective drying chambers. Further, in the wind box 4 a on the front stage side, the region immediately below the charging chute 8 is isolated from the other regions by the partition plate 14. Specifically, as shown in FIG. 1 (c) or FIG. 1 (d), the partition plate 14 is arranged to isolate the region immediately below the charging chute 8 from other regions.

  Coal powder, which is a wet raw material, is charged into the fluidized bed dryer 3 by the charging chute 8 and forms a fluidized bed 9 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 9, and the coal powder is adjusted to a predetermined temperature and moisture content and is discharged by the discharge chute 10.

  A first bypass pipe 11 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 at the upper part of the fluidized bed dryer 3 through the first bypass pipe 11. The hot gas introduced by the first bypass pipe 11 is for preventing the occurrence of condensation near the gas outlet 6 and downstream thereof.

  Further, the second bypass pipe 12 branches from the gas main pipe 2, and the region immediately below the charging chute 8 of the wind box 4 a isolated by the partition plate 14 is heated by the second bypass pipe 12. Gas is introduced, and hot gas is introduced into the other region by the gas main pipe 2. The second bypass pipe 12 is provided with a flow control valve 15, and the gas main pipe 2 is also provided with a flow control valve 16 on the downstream side of the branch point of the second bypass pipe 12.

  In the above configuration, in this embodiment, the flow rate control valves 15 and 16 provided in the second bypass pipe 12 and the gas main pipe 2 are adjusted, and the heat source is also blown from the lower side of the gas dispersion plate 5 immediately below the charging chute 8. The flow rate of the fluidizing gas is set to be faster than the flow rate of the heat source / fluidizing gas blown from the lower side of the gas dispersion plate other than directly below the charging chute. As a result, clogging is less likely to occur in the gas dispersion plate 5 immediately below the charging chute 8 where clogging is likely to occur, and clogging of the gas dispersion plate 5 can be prevented.

  In the above embodiment, the flow rate of the heat source / fluidizing gas blown from the lower side of the gas dispersion plate 5 immediately below the charging chute 8 is increased by adjusting the high temperature gas flow rates of the second bypass pipe 12 and the gas main pipe 2. However, the same object can be achieved by adjusting the pipe diameters of the second bypass pipe 12 and the gas main pipe 2 or by providing a gas pressurizing device in the second bypass pipe 12.

  In the above embodiment, the high temperature gas is introduced into the region immediately below the charging chute 8 of the wind box 4a by the second bypass pipe 12 branched from the gas main pipe 2, but an independent gas pipe is provided separately. May be.

  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.

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 Partition Wall 8 Charge Chute 9 Fluidized Bed 10 Discharge Chute 11 First Bypass Pipe 12 Second bypass pipe 14 Partition plate 15, 16 Flow control valve

Claims (2)

Wetting with a fluidized bed dryer that charges wet raw material from the charging chute, blows hot gas from the lower side of the gas dispersion plate as a heat source and fluidizing gas, forms a fluidized bed on the gas dispersion plate, and dries the wet raw material In the method of drying raw materials,
The flow rate of the heat source / fluidized gas blown from the lower side of the gas dispersion plate just below the charging chute is made faster than the flow rate of the heat source / fluidized gas blown from the lower side of the gas dispersion plate other than directly below the charging chute. A method for drying a wet raw material using a fluidized bed dryer. In a fluidized bed dryer that charges a wet raw material from a charging chute, blows a high temperature gas as a heat source and fluidizing gas from the lower side of the gas dispersion plate, forms a fluidized bed on the gas dispersion plate, and dries the wet raw material.
The flow rate of the heat source / fluidized gas blown from the lower side of the gas dispersion plate just below the charging chute is made faster than the flow rate of the heat source / fluidized gas blown from the lower side of the gas dispersion plate other than directly below the charging chute. Fluidized bed dryer.

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