JP7260751B2 - Fluidized dryer - Google Patents

Description

The present invention relates to a fluidized bed dryer.

Conventionally, when coke is produced, for example, coal is dried, classified and preheated before carbonization. A fluidized bed dryer is used as a device for drying, classifying, and preheating. The fluidized bed drying apparatus includes a drying chamber (freeboard section) having a fluidized bed on the floor surface for drying, etc., while fluidizing the fed raw material coal, and a plenum chamber provided on the lower surface side of the fluidized bed. ing. A plurality of outlets (also called perforated plates) are formed in the fluidized bed. The high-temperature fluidizing gas (dry gas) introduced into the plenum chamber is blown out from the blowout port into the drying chamber, dries and heats the raw material coal, fluidizes the coal on the fluidized bed, and discharges downstream. Move to the exit side.

Here, the charging of coal, which is the raw material, into the freeboard portion is performed through a charging chute provided on the upstream side wall of the fluidized bed dryer. A charging chute is a flat-topped passage with an inclination angle of, for example, about 20 degrees between vertical side walls. Therefore, the coal charged from the charging chute draws a parabola derived from the relationship between the initial charging speed, the inclination angle, the sliding distance on the chute, the gravitational acceleration, etc. from the end of the charging chute and falls onto the fluidized bed. do. The fallen coal forms a fluidized bed on the fluidized bed, is heated and dried by the fluidizing gas blown out from the outlet, and is fluidized.

However, in this type of fluidized bed dryer, when the moisture content of the coal to be introduced into the charging chute increases, the coal becomes slurry (suspension) or increases in mass, and the coal flows along the side wall as it is. fall almost vertically. As a result, coal in such a state cannot maintain the above-mentioned fluidized bed, and raw material accumulates in the fluidized bed immediately below the chute, causing clogging of the outlet of the fluidized bed.

If such a situation occurs, insufficient drying will continue, so it will be necessary to stop the equipment and remove the raw material clogging. Due to such equipment stoppage, the production capacity is lowered, and it takes a lot of labor to remove the clogging, which is a great disadvantage.

Therefore, in order to prevent the occurrence of such a situation, in Patent Document 1, the charging chute itself is composed of a punching plate in which a large number of pores are formed, and at the same time, the side wall of the fluidized drying device is applied to the punching plate. It is proposed to blow out hot air separately

Japanese Utility Model Laid-Open No. 5-3891

However, in the technology disclosed in Patent Document 1, in order to blow hot air from the side wall of the fluidized bed dryer, the fluidized bed dryer itself needs to be significantly modified. Therefore, it cannot be easily applied to existing facilities.

The present invention has been made in view of this point, and can be easily applied to existing facilities. The purpose is to maintain a fluidized bed on the bed and achieve appropriate drying and fluidization.

In order to achieve the above object, the present invention provides a drying chamber for flowing and drying raw materials, a charging chute for charging the raw materials into the drying chamber on the upstream side wall of the drying chamber, and a floor of the drying chamber. and a fluidized bed having a plurality of dry gas outlets on its surface, wherein a chute extension is provided at the end of the charging chute, and the end of the chute extension is spaced apart from the side wall. The extension length of the chute extension is such that some of the plurality of outlets are positioned below the chute extension in a plan view, and the end of the chute extension is is not in contact with the fluidized bed, and there is a space below the chute extension , and all of the blowout opening portions of the blowout openings located on the side closest to the side wall than the terminal end are is contained within the space in plan view .

According to the present invention, a chute extension is provided at the end of the charging chute, and the end of the chute extension is separated from the side wall. , falls away from the upstream side wall of the drying chamber. Moreover, compared with the case where the raw material is dropped directly from the charging chute, the horizontal velocity is faster, so the raw material dropped into the fluidized bed easily flows downstream of the drying chamber. Therefore, even if the raw material to be charged increases in moisture content and becomes slurry or increases in mass, it is prevented that the raw material falls vertically along the side wall and deposits as it is. In addition, as described above, since it is easy to flow toward the downstream side of the drying chamber, it is possible to maintain fluidity and maintain a predetermined dry state and temperature.
In order to carry out the present invention, it is only necessary to provide a chute extension at the terminal end of the charging chute, so it is extremely easy to apply to existing equipment.

Furthermore, in the present invention, the extension length of the chute extension is such that a part of the outlet is positioned below the chute extension in a plan view, and the end of the chute extension is the fluidized bed. and a space exists below the chute extension.

By adopting such a configuration, the dry gas from the outlet located below the chute extension collides with the chute extension, and then follows the lower surface of the chute extension toward the terminal end of the chute extension, that is, flows downstream. Therefore, the downstream flow of the dry gas facilitates the material dropped from the chute extension to flow further downstream. In addition, the drying gas promotes drying while falling, so the fluidity is further increased.

The width of the chute extension may be set to have a length of ⅓ or more of the width of the fluidized bed. By having such a width, the raw material that slides down from the charging chute can be dropped into the fluidized bed over a wider range in the width direction. Moreover, the dry gas from the blow-out port located below the chute extension can also be supplied over a wider range to the material dropping from the end of the chute extension.

The chute extension may have a flat plate shape. As a result, the dry gas blown to the lower surface side of the chute extension is in contact with the lower surface side of the chute extension for a longer time, and the contact area is increased, so the chute extension itself is heated. , the feedstock on the chute extension can be preheated and the moisture in the feedstock can be reduced.

In view of such effects, it is preferable that the chute extension is generally made of metal having good thermal conductivity.

According to the present invention, it is possible to maintain the fluidized bed on the fluidized bed and realize appropriate drying and fluidization even if the moisture content of the raw material increases without significantly modifying existing equipment.

BRIEF DESCRIPTION OF THE DRAWINGS It is explanatory drawing which showed typically the outline|summary of the fluidized-bed drying apparatus concerning embodiment from the side. FIG. 2 is an explanatory view schematically showing the configuration of a chute extension part in the fluidized bed dryer of FIG. 1 from the side; FIG. 2 is an explanatory view showing the action of the chute extension in the fluidized bed dryer of FIG. 1; FIG. 2 is an explanatory view showing the action of the chute extension in the fluidized bed dryer of FIG. 1; FIG. 2 is an explanatory view showing the action of the chute extension in the fluidized bed dryer of FIG. 1; FIG. 2 is a perspective view showing the action of the chute extension in the fluidized bed dryer of FIG. 1; Changes in layer thickness and productivity due to time-series changes in the moisture content of coal in a fluidized bed dryer without a chute extension, (a) is the time-series change in the moisture content of coal, and (b) is the layer thickness. and (c) shows the change in productivity. Changes in layer thickness and productivity associated with time-series changes in the moisture content of coal in a dynamic drying apparatus with a chute extension, (a) is the time-series change in the moisture content of coal, and (b) is the change in layer thickness. , (c) shows the change in productivity.

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. FIG. 1 is an explanatory view showing the outline of a fluidized bed dryer 1 according to an embodiment from the side. It is configured as a preheating device. The fluidized bed dryer 1 has a drying chamber 2 for fluidizing and drying coal as a raw material. The upper surface of the drying chamber 2 is provided with a plurality of pulverized coal outlets 3 for discharging pulverized coal produced during the fluidized drying to the outside of the room.

The floor surface of the drying chamber 2 is composed of a fluidized bed 4 . A plenum chamber 5 is provided on the lower side of the fluidized bed 4, and a high-temperature drying gas for fluidizing and drying the coal is introduced. The drying gas introduced into the plenum chamber 5 is blown into the drying chamber 2 from a large number of outlets 6 called perforated plates provided in the fluidized bed 4 . The blowout port 6 is formed over the entire surface of the fluidized bed 4 between a side wall 7 forming one side wall of the drying chamber 2 in the fluidized bed drying apparatus 1 and a side wall 8 forming the other side wall. The side wall 8 constitutes the upstream side wall of the coal flowing in the drying chamber 2 and the side wall 8 constitutes the downstream side wall.

The side wall 7 is provided with a charging chute 11 for charging coal as a raw material into the drying chamber 2 . As shown in FIG. 2, the charging chute 11 is inclined so that the angle .theta.

A chute extension 12 is provided at the terminal end of the charging chute 11 . The chute extension 12 is made of a metal plate and fixed to the side wall 7 by a stay 13 in this embodiment. The surfaces of the chute extension 12 and the charging chute 11 form continuous slopes with the same angle of inclination.

As described above, the chute extension 12 is a flat metal plate and is fixed to the side wall 7 by the stay 13. Therefore, between the chute extension 12 and the side wall 7, a space S1 having a triangular vertical cross section is formed. is formed. A space S2 having a rectangular longitudinal section is formed continuously with the space S1 on the lower surface side of the space S1.

As shown in FIG. 2, the length of the chute extension 12 is set so that the outlet 6a closest to the side wall 7 is positioned below the chute extension 12 in plan view. Of course, another outlet 6b positioned downstream of the outlet 6a may be positioned below the chute extension 12 in plan view.

The position of the end portion 12a of the chute extension 12 due to such configuration and installation is away from the side wall 7 and does not contact the fluidized bed 4. As shown in FIG.

The fluidized bed drying apparatus 1 according to the embodiment has the above configuration, and the effects and the like thereof will be described below. As shown in FIG. 3, the chute extension 12 is continuously provided at the terminal end of the charging chute 11, and the terminal end 12a of the chute extension 12 is separated from the side wall 7, so that the charging chute 11 Coal charged from the chute extension 12 falls onto the fluidized bed 4 from the terminal end 12a along the parabola indicated by the solid line. Therefore, compared with the drop without the chute extension 12 indicated by the dashed line, the drop will fall farther from the side wall 7 than conventionally.

Therefore, as shown in FIG. 4, compared with the prior art without the chute extension 12, even if the charged coal contains a large amount of coal, the side wall 7 4. Because of its greater horizontal velocity than without the chute extension 12, it is forced in the direction of flow indicated by arrow A in FIG. In this regard, in the absence of the chute extension 12, as indicated by the broken line in FIG. Therefore, compared with the case without the chute extension 12, the fallen coal has better fluidity and is prevented from accumulating near the wall of the side wall 7.

Moreover, in this embodiment, as described above, the length of the chute extension 12 is set so that the outlet 6a closest to the side wall 7 is positioned below the chute extension 12 in plan view. , the fallen coal does not drop to the position of the blowout port 6a, but falls to the vicinity of the blowout port 6b or the farther away from the side wall 7 than the blowout port 6a. In addition, since the outlet 6a closest to the side wall 7 is positioned below the chute extension 12 in a plan view, even if the chute extension 12 falls vertically from the terminal end 12a, It will not fall.

Therefore, the blowout port 6a is never clogged, and the dry gas can always be blown upward as shown in FIGS. Then, the dry gas blown out from the blowing port 6a hits the lower surface side of the chute extension 12, and then along the lower surface of the chute extension 12 toward the downstream side (the arrow A side in FIG. 5). flow. On the other hand, the dry gas blown out from the other outlets 6b and 6c is influenced by the dry gas blown out from the outlet 6a and flowing toward the downstream side (the arrow A side in FIG. directed to.

Then, as shown in FIGS. 5 and 6, these dry gases collide with the flow of coal C which is successively charged from the charging chute 11 and drops from the chute extension 12, causing the coal to A downstream force is applied to C, making it easier to flow further downstream.

In addition, coal CC (Fig. 5) with a high moisture content and a large amount of moisture generally reaches the surface side of the charging chute 11 and the chute extension 12 when flowing along the charging chute 11 and the chute extension 12. As a result, when it falls from the chute extension 12, it tends to occupy a position close to the side wall 7 side. Therefore, the dry gas from the outlets 6a, 6b, 6c, which is directly blown from the direction of the side wall 7 against the flow of the coal C, is blown onto the coal CC with a large amount of moisture. Therefore, the water content of the coal with a large amount of water, which causes the coal to lose its fluidity, is reduced when it falls into the fluidized bed 4, and from this point as well, the fluidity of the dropped coal C is improved.

Furthermore, in the above-described embodiment, the space S1 on the lower surface side of the chute extension 12 is constantly blown with high-temperature dry gas from the outlet 6a, so that the chute extension 12 is heated. Therefore, the coal C is preheated by the chute extension 12 while the coal C falls along the chute extension 12 . Therefore, from this point of view as well, the coal dropped onto the fluidized bed 4 is more likely to maintain its fluidity. Further, since the chute extension 12 in the above-described embodiment is a metal plate, it has good thermal conductivity and the heating efficiency for the coal C on the chute extension 12 is good.

Since the fluidized bed drying apparatus 1 according to the embodiment having such an effect can be realized only by providing the chute extension 12 at the terminal end of the charging chute 11, the existing equipment can be greatly modified. can be implemented without

As described above, according to the fluidized bed drying apparatus 1 according to the embodiment, even if the moisture content of such raw materials such as coal increases, fluidization on the fluidized bed can be achieved without greatly modifying the existing equipment. It is possible to maintain the layer and achieve proper drying and fluidity.

In the above-described embodiment, the length of the chute extension 12 is set so that only the outlet 6a closest to the side wall 7 is located below the chute extension 12 in a plan view, but the present invention is not limited to this. The length of the chute extension 12 may be adjusted so that the outlets 6b and 6c, which are successively separated from the outlet 6a, are also positioned below the chute extension 12. As shown in FIG.

Next, the result of demonstrating the effect of the fluidized drying apparatus according to the embodiment will be described. FIG. 7 shows the results of a conventional fluidized bed dryer without chute extensions at the end of the charging chute, and FIG. Results for drying equipment are shown. In both FIGS. 7 and 8, (a) shows time-series changes in moisture contained in raw material coal. In this case, the time series indicates changes in the coal charged into the fluidized drying chamber for each charging day. Since fluctuations in water content are affected by the weather and the humidity of the outside air, the water content rate differs for each measurement day. 7 and 8 are different in the variation and value of the moisture content because the implementation dates (measurement dates) are different.

Each (b) in FIGS. 7 and 8 shows the thickness of the A layer at that time. By A layer thickness is meant the layer of coal formed in the fluidized bed of the block which conveniently divides the drying chamber into four blocks and is closest to the side wall provided with the charging chute. The unit of layer thickness is given in kPa, but since it is difficult to actually measure the thickness of the layer, the difference between the pressure of the gas in the plenum chamber and the pressure of the gas coming out of the coal layer in the drying chamber, that is, The pressure loss due to the coal layer is used as a substitute, and the higher the value, the thicker the layer, which means that the coal is stagnating without flowing.

(c) in FIGS. 7 and 8 is a graph showing the productivity when coke is produced after being processed by the fluidized bed dryer, and the higher the value, the better the productivity.

As can be seen from FIGS. 7 and 8, in the conventional fluidized bed dryer which does not have a chute extension at the terminal end of the charging chute, the higher the moisture content of the coal, the thicker the A layer thickness and the more the fluidity. sexuality is declining. As a result of the decrease in fluidity, the fluidized bed dryer has to be stopped, and the temperature of the coal charged into the coke oven is lowered.

On the other hand, according to the fluidized bed drying apparatus in which a chute extension is provided at the terminal end of the charging chute, as shown in FIG. The thickness has changed little and therefore the subsequent coke productivity remains at the highest level. This confirmed the effectiveness of the present invention.

INDUSTRIAL APPLICABILITY The present invention is useful for fluidized drying of various raw materials including coal.

REFERENCE SIGNS LIST 1 fluidized bed dryer 2 drying chamber 3 pulverized coal outlet 4 fluidized bed 5 plenum chamber 6, 6a, 6b, 6c outlet 7, 8 side wall 11 charging chute 12 chute extension 12a terminal end 13 stay C coal CC moist Coal S1, S2 Space

Claims (4)

A drying chamber for flowing and drying the raw material, a charging chute for charging the raw material into the drying chamber on an upstream side wall of the drying chamber, and a plurality of dry gas outlets on the floor of the drying chamber. In a fluidized dryer having a fluidized bed,
A chute extension is provided at the terminal end of the charging chute,
a terminal end of the chute extension is remote from the sidewall;
The extension length of the chute extension is such that some of the plurality of outlets are located below the chute extension in a plan view,
a terminal end of the chute extension is not in contact with the fluidized bed, and a space exists below the chute extension ;
A fluidized bed drying apparatus, wherein a blowing opening portion of a blowing port located on a side closest to the side wall than the end portion is entirely contained in the space in a plan view. 2. The fluidized drying apparatus according to claim 1, wherein the width of said chute extension is 1/3 or more of the width of said fluidized bed. 3. The fluidized bed drying apparatus according to claim 1, wherein said chute extension has a flat plate shape. 4. The fluidized bed dryer of claim 3, wherein said chute extension is made of metal.

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