JPH05209180A - Drying machine - Google Patents

Abstract

PURPOSE:To provide a drying machine capable of efficiently drying the granules of coal, etc., in a narrow installation area. CONSTITUTION:A downward flow rate-controlling member (retarder) 25 for prolonging the residence time of the granules is disposed in a single cylindrical and double tube type drying machine, which is constituted so as to indirectly heat the granules by incorporatedly rotating a tilted inner tube 6 and a tilted outer tube 7, feeding the granules into the inner tube 6, stirring the granules by the movement of the kiln and supplying a heating medium such as steam between the inner tube 6 and the outer tube 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a single-cylinder / double-tube type drier capable of efficiently drying powdery particles in a small installation area.

[0002]

2. Description of the Related Art A case of handling coal as a powder or granular material will be described. Generally, the coal storage yard is an outdoor yard, and the coal loaded in the open field has a particularly large amount of water in the rainy season and its adhesion becomes significantly large, which is a cause of transportation trouble and corrosion trouble. On the other hand, if it is too dry,
Alternatively, it is known that if it is dried directly with heated gas or is excessively stirred, the dust generation property is increased, and there is a risk of fire and dust explosion. Furthermore, the wear properties of powder and granules,
There are problems such as increased corrosivity due to concentration of water-soluble corrosive substances.

US Pat. No. 3,765,102 describes
A multi-tube, material-in-tube type powder-and-particle dryer is described. This device is provided with a vertical fin-shaped flat bar inside the tube, and is provided with a stirring means for scraping up the powder layer to expand the contact area with the heat transfer surface. Further, JP-A-1-230916 also describes a multi-tubular, material-in-tube type coal drying apparatus. This device is provided with a stirring means made of a spiral wire rod in a tube.

[0004]

The above-mentioned multi-tube type (multi-stage type) dryer is effective for drying a large amount of powder or granular material such as coal, but it has a problem that it occupies a large site area. is there. Since coal is transported by the belt conveyor,
It is desirable to be able to arrange the dryers in parallel on the transfer line or in-line during the transfer. The present invention has been made in view of the above points, and an object thereof is to provide an efficient dryer that can be easily arranged in parallel or in-line on a conveyance line in a small site area. Is.

[0005]

To achieve the above object, the dryer of the present invention, as shown in FIG. 1, rotates an inclined inner tube 6 and an inclined outer tube 7 as a unit, A single-body double tube in which the granular material is introduced into the inner tube 6 and stirred by a kiln operation, and a heating medium is supplied between the inner tube 6 and the outer tube 7 to indirectly heat the granular material. Type drier, the flow-down speed control member 25 for extending the residence time of the granular material.
Is arranged in the inner pipe 6. In the above dryer, the heating medium is steam, the flow-down speed control member 25 is a spiral body, and the scraping cover 24 is provided around the outer pipe 7 at the portion where the powder particle inlet 5 is provided. It is desirable that two guide rings 22, 22 are attached around the outer tube in the cover 24, and further, the scraping blade 23 is attached to the outer tube 7 so as to be located between these guide rings.

[0006]

The powder / granule supplied from the powder / granule inlet 5 flows down in the rotating inner pipe 6 while performing the kiln operation, and is discharged from the powder / granule outlet 26. The kiln operation is a phenomenon in which powder particles rise in the direction of rotation of the inner cylinder, and when the rising angle is greater than or equal to the angle of repose, the powder particles collapse to stir and flow down. The flow-down speed depends on the rotation speed of the machine and the inclination angle.However, the flow velocity of dried powder and granules is higher than that of the powder at the inlet, so the kiln operation becomes unstable and the downstream of the inner pipe becomes unstable. The residence time of the powder and granules is significantly reduced. By arranging the flow-down speed control member (retarder), the kiln operation is stabilized, and due to the effect of backflowing the granular material in the inlet direction, it is possible to shorten the machine length while maintaining the residence time. Within the inner tube 6, the agitation phenomenon of the powder and granular material is maintained by this kiln operation. At this time, it is heated by a heating medium from the outside. The adhered water and the contained water of the granular material evaporate because the granular material itself is heated. Part of the water adheres to the inner wall of the inner tube and immediately evaporates. Thus, the dry atmosphere is maintained at a low oxygen concentration by the evaporated water. On the other hand, on the inner wall of the inner pipe, in the case of coal, the water containing the components eluted from the granular material is deposited by evaporation to dryness, and the equilibrium state of wear due to the kiln operation is exhibited, but due to indirect heating by steam with good heat transfer performance. Since the temperature of the tube wall can be maintained at a high temperature such that the water content is liquid and does not exist on the inner wall of the inner tube, that is, uniform heating can be achieved, an environment that does not lead to corrosion can be created. In addition, the effects of the above-described kiln operation of powder and granular material and indirect heating are that the agglomerated fine particles are broken, or the fine particles are selectively overdried with a high temperature gas,
Furthermore, it is aimed to achieve a drying operation under oxygen concentration without dust explosion.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described in detail below with reference to the drawings, in the case where the powder or granular material is coal. However, the shape of the constituent devices described in this embodiment, the relative arrangement thereof, and the like, unless otherwise specified, are not intended to limit the scope of the present invention only to them, but merely illustrative examples. Nothing more. FIG. 1 shows an embodiment of the dryer of the present invention, and FIG. 2 shows an enlarged cross section taken along line II-II in FIG. The coal conveyed by the coal supply conveyor 1 is thrown into the hopper 2 and supplied from the granular material inlet 5 into the inclined inner pipe 6. Reference numeral 3 is a ribbon mixer, a mixer such as a screw, and 4 is a geared motor.
The coal supplied from the granular material inlet 5 flows down in the inner pipe 6 while performing a kiln operation, and is discharged to the hopper 14 from the granular material outlet 26 provided on the lower side of the lower ends of the inner pipe and the outer pipe, and discharged. It is conveyed to the outside by the conveyor 15. The slanted inner tube 6 is concentrically provided in the slanted outer tube 7, and both are configured to rotate integrally. Rotating shafts 27 and 28 at both ends of a rotating body which is an integral body of the inner pipe 6 and the outer pipe 7 are supported by a free bearing 11 and a fixed bearing 9, and are driven by a motor 12 via a coupling 10. 8 is a transmission shaft. In the space between the inner pipe 6 and the outer pipe 7, the steam inlet 1
Steam is supplied from 9 to heat the coal in the inner pipe 6. The condensate collects in the lower part of the cap 16 at the lower end of the outer pipe 7, and is discharged from the condensate discharge pipe 21 due to the siphon effect and pressure difference of the siphon pipe 20 inserted in this condensate.

A gas discharge port 29 is provided above the lower ends of the inner pipe 6 and the outer pipe 7, and a cover 30 on the upper side of the gas discharge port 29 is connected to a suction means (not shown). A gas exhaust pipe 13 is provided. 17 is a flange,
18 is a rotary joint. With respect to the adherence of coal, the hoppers 2 and 14 have a steam trace (braid) or a jacket structure to prevent condensation inside due to heat radiation from the outside air during both operation and stop. it can. In order to continuously supply the coal dropped in the hopper 2 without forming a bridge, it is effective to provide a stirring device or a vibration device. A scraping cover 24 is provided around the outer tube 7 in the portion where the powdery or granular material inlet 5 is provided, and two guide rings 22, 22 are attached around the outer tube in the scraping cover 24. There is. Further, the scraping blade 23 is attached to the outer tube 7 so as to be located between these guide rings. It is desirable that the scraping cover 24 has a divided structure. Scraping blade 23
Is for scraping off the supplied coal so as not to solidify, and prevents wear of the outer tube 7. Further, since it is a single cylinder, the diameter of the inner pipe 6 becomes large. Therefore, by configuring the scraping blade 23 and the scraping cover 24 to have a large clearance, it is possible to supply coal having a large particle size. Becomes

In the inner pipe 6, since the fluidity of dried coal increases, a downflow speed control member (retarder) 25 is arranged to suppress it. As an example of the retarder 25, a spiral body 40 formed by spirally forming a rod as shown in FIG. 3 is used. In this case, if the spiral turning direction is set to the twisting direction opposite to the rotating direction of the inner pipe 6, the push-back effect of coal becomes greater. A plate-shaped member 31 is attached to the lower end of the retarder 25, and the plate-shaped member 31 comes into contact with a stopper 32 fixed to the lower end of the inner pipe 6. Therefore, as the inner pipe 6 rotates, the retarder 25 rotates together with the granular material, and the lower part of the retarder 25 is always
Touches the inner bottom wall of the. The above-mentioned spiral body is shown as an example, and it is needless to say that the spiral body can have another shape.
For example, as shown in FIG. 4, a retarder 25a having a spiral body 44 provided around a plurality of rods 42, a retarder 25b having a spiral body 48 provided around a rod 46 as shown in FIG. 5, and as shown in FIG. A retarder 25c in which a screw-shaped spiral body 52 is provided around the shaft 50 is used. 54 is a cap, and 56 is a support member.

The angle θ formed by the outer tube 7 and the horizontal line is preferably 3 to 10 ° when the granular material is coal. Also,
When the granular material is coal, the inner diameter of the inner pipe 6 is 150 mm or more,
It is desirable to set it to 200 to 1000 mm. Next, the experimental results in the apparatus shown in FIGS. (1) Inner diameter of inner tube is 300mm, effective length is 4000mm
And 10% water content at inlet of coal, steam pressure 10kg / cm
² G, when the processing amount of the coal to 745kg / hr (wet basis), the outlet water 7.1%, steam consumption 65 kg / hr
Met. (2) Inner diameter of inner tube is 500mm, effective length is 4000mm
And 10% water content at inlet of coal, steam pressure 10kg / cm
² G, the throughput of coal is 1760 kg / hr (wet basis)
If so, the outlet water content is 8.7% and the steam consumption is 112 kg.
/ Hr. (3) Inner diameter of inner tube is 500mm, effective length is 4000mm
And 10% water content at inlet of coal, steam pressure 10kg / cm
² G, the throughput of coal is 1160 kg / hr (wet basis)
If so, outlet water content is 6.0%, steam consumption is 108 kg.
/ Hr.

[0011]

Since the present invention is constructed as described above, it has the following effects. (1) Since a downflow speed control member (retarder) for extending the residence time of powder and granules is provided in the single-cylinder, double-tube type dryer, a small site area can be installed in parallel or inline on the transfer line. In addition to being arranged, the powder and granules can be efficiently dried. (2) For drying a large volume of granular material with a small water drop that does not generate dust, that is, a difference in water content between the inlet and the outlet (for example, in coal, the water drop is improved by about 2 to 5%). Are suitable.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view showing an embodiment of a dryer of the present invention.

FIG. 2 is an enlarged cross-sectional explanatory view taken along line II-II in FIG.

FIG. 3 is a perspective view showing an example of a downflow speed control member (retarder) used in the apparatus of FIG.

FIG. 4 is a perspective view showing another example of a retarder.

FIG. 5 is a perspective view showing another example of a retarder.

FIG. 6 is a perspective view showing still another example of the retarder.

[Explanation of symbols]

 5 Powder / granule inlet 6 Inner tube 7 Outer tube 12 Motor 22 Guide ring 23 Scraping blade 24 Scraping cover 25 Downflow speed control member (retarder) 26 Powder / granule outlet 29 Gas outlet

Claims (2)

[Claims] 1. A slanting inner tube (6) and a slanting outer tube (7) are integrally rotated, and powder particles are introduced into the inner tube (6) and agitated by a kiln operation to form an inner tube ( In a single-cylinder / double-tube type dryer in which a heating medium is supplied between the outer tube (6) and the outer tube (7) to indirectly heat the granular material, it is necessary to extend the residence time of the granular material. A drier characterized in that a flow-down speed control member (25) is arranged in the inner pipe (6). 2. The scraping cover (24) around the outer tube (7) in the portion where the powder particle inlet (5) is provided, wherein the heating medium is steam, the downflow speed control member (25) is a spiral body. )
Is provided, two guide rings (22), (22) are attached around the outer tube in the scraping cover (24), and the scraping blade (23) is positioned so as to be located between these guide rings. The dryer according to claim 1, wherein the dryer is attached to the outer tube (7).