RU2352879C1 - Fluidised bed drier and drying method of wet raw material using fluidised bed drier - Google Patents

Abstract

FIELD: oil and gas industry. ^ SUBSTANCE: invention refers to fluidised bed drier meant for drying wet raw material, such as coal supplied to coke furnace, and to drying method of wet rough pulverised coal using fluidised bed drier. Fluidised bed drier for supplying wet material through a feed chute and blowing down high-temperature gas from under gas-distributing plate used as heating gas and fluidising gas so that fluidised bed can be formed on gas-distributing plate for drying wet raw material consists of gas-blowing atomiser located in the area of external wall between feed chute bottom and fluidised bed for dispersing wet raw material flow, which falls from feed chute; at that injection rate of heating and fluidising gas flow from under gas-distributing plate directly to the area under feed chute is higher than rate of flow injected into other areas from under gas-distributing plate. By using such device, wet raw material supplied from feed chute does not fall intensively directly to the area under feed chute. ^ EFFECT: preventing gas-distributing plate from being blocked. ^ 4 cl, 11 dwg

Description

Technical field

The present invention relates to a fluid bed dryer for drying wet raw materials such as coal loaded in a coke oven, and a method for drying a wet crude powder using a fluid bed dryer.

State of the art

In the production of cokes, the loaded coal is dried before being fed into the coke oven to improve the quality of cokes and the productivity of the coke oven. The moisture content of the non-dried coke of the coke oven is generally about 9-13%, and the coals are dried in coal dryers to a moisture content of 5-6%.

It is known to use fluidized bed dryers for drying such coals. For example, in the fluidized bed dryer disclosed in Patent Document 1, wet feed is loaded onto a gas distribution plate through a loading tray, and heating and fluidizing gas is supplied from under the gas distribution tray such that a fluidized bed is formed on the gas distribution tray and the wet, crude feed is dried in the fluidized bed.

However, according to such a conventional fluidized bed dryer, since the wet feed is loaded into the space of the fluidized bed on a gas distribution plate directly below the loading tray at a decreasing speed, in the space immediately below the loading tray, the small openings of the gas distribution plate are clogged with the wet raw material thus loaded. This causes incomplete drying due to the cessation of liquefaction. In addition, the clogged openings of the gas distribution plate must be punched to remove the clog each time the fluidized bed dryer is stopped for repair, so a tremendous amount of time and work is required.

Patent Document 1: Japanese Patent Publication No. 2938029.

SUMMARY OF THE INVENTION

It is an object of the present invention to prevent clogging of a gas distribution plate of a fluidized bed dryer with wet raw materials loaded in a loading tray.

In the present invention, the task is achieved by dispersing the flow of moist raw materials falling from the loading tray, or by increasing the flow rate of the heating and fluidizing gas injected into the space directly under the loading tray from under the gas distribution plate.

In other words, according to a first embodiment of the present invention, when drying wet materials in a fluidized bed dryer, for loading wet materials through a loading tray and supplying high temperature gas as a heating and fluidizing gas from under the distribution plate so as to form a fluidized bed on the gas distribution plate for drying wet raw materials, gas is blown through a gas-blowing nozzle mounted on the outer wall, between the base of the loading tray and the pseudo a fluidized bed to disperse the flow of wet raw materials falling from the loading tray.

According to the first embodiment, part of the high-temperature gas can be used as gas blown from the gas blower nozzle.

According to a second embodiment of the present invention, when the wet raw material is dried by a fluidized bed dryer, for loading the wet raw material through the loading tray and supplying high temperature gas as a heating and fluidizing gas from under the distribution plate so as to form a fluidized bed on the gas distribution plate for drying the wet raw materials, flow rate of heating and fluidizing gas, blown into the space directly under the loading tray from under the gas distribution lath, is installed faster than the flow rate of heating and fluidizing gas injected into other areas of space, not directly below the loading tray from under the gas distribution plate.

According to the present invention, the wet feed stream falling from the loading tray is dispersed in such a way that the wet flow from the loading tray does not fall intensively on a certain area directly below the loading tray and the gas distribution plate is protected from clogging.

Further, according to the present invention, the flow rate of the heating and fluidizing gas injected into the space immediately below the loading tray from under the gas distribution plate is accelerated in such a way that clogging rarely occurs in the gas distribution region immediately below the loading tray, where it often occurs, and the gas distribution the plate is protected from clogging.

Brief Description of the Drawings

1A is a longitudinal sectional view showing a first embodiment of a fluidized bed dryer according to the present invention;

Figure IB is a sectional view I-I taken in Figure IA;

Figure 2 is a main view showing the conditions for purging high-temperature gas through a gas blower;

3A is a view showing the construction of a gas blower nozzle;

3B is a view showing the construction of a gas blower nozzle;

4A is a cross-sectional view showing a preferred arrangement of a gas nozzle;

Fig. 4B is a longitudinal sectional view showing a preferred arrangement of the gas nozzle;

5A is a longitudinal sectional view showing a second embodiment of a fluidized bed dryer according to the present invention;

Figv is a view of section II-II taken in Fig.5A;

Fig. 5C is a sectional view of III-III taken in Fig. 5A; and

Fig. 5D is a sectional view of III-III taken in another example of Fig. 5A.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Embodiments of the present invention will be described based on applications of the present invention for drying coal powder for a coke oven (hereinafter referred to simply as “coal powder”).

First Embodiment

FIG. 1A is a longitudinal sectional view of a first embodiment of a fluidized bed dryer according to the present invention, and FIG. 1B is a view I-I taken in FIG. 1A.

As shown in FIGS. 1A and 1B, an exhaust gas of combustion (hereinafter referred to as “high temperature gas”) having a temperature of about 150-250 ° C. generated in a coke oven (not shown) is compressed by compressor 1 and sent to blowing chambers 4a and 4b , which are located under the dryer 3 with a fluidized bed, on the gas line 2, as a heating and fluidizing gas. The high-temperature gas entering the blast chambers 4a and 4b flows from bottom to top through a gas distribution plate 5 located above the blast chambers 4a and 4b and is removed through a gas exhaust line 6. The space in the dryer 3 with a fluidized bed is divided into two separation chambers 3a, 3b the partition 7, and the blast chambers 4a and 4b are located under the drying chambers, respectively.

The coal powder as wet feed is loaded into the fluidized bed dryer 3 using a loading tray 8, and a fluidized bed 9 is formed on the gas distribution plate 5 by increasing the air flow by supplying high temperature gas through the gas distribution plate 5. The coal powder is dried in this fluidized bed 9 so as to have a predetermined temperature and moisture content ratio and is unloaded by the discharge tray 10.

The first bypass pipe 11 extends from the gas line 2, and through the first bypass pipe 11, a portion of the high temperature gas is introduced into the space near the gas exhaust line 6 in the upper part of the fluidized bed dryer 3. The high temperature gas introduced into the first bypass pipe 11 prevents the formation of a condensation point around and downstream of the gas exhaust line 6.

Then, from the first bypass pipe 11, a second bypass pipe 12 passes, through this second bypass pipe 12 a part of the high-temperature gas is blown into the gas blower nozzle 13. The gas blower nozzle 13 is located on the outer wall portion 3c, between the base of the feed chute 8 and above the fluidized bed 9, and through gas blower 13, a portion of the high temperature gas is blown into the fluidized bed dryer 3. Here, the second bypass pipe 12 may branch off from the gas line 2.

Figure 2 schematically shows the conditions for blowing high-temperature gas through the gas blower nozzle 13. As shown in Figure 2, the high-temperature gas blown through the gas blower nozzle 13 disperses the flow of coal powder (wet feed) so that the coal powder falling from the loading tray 8, does not fall intensively into the area immediately below the loading tray 8. With this design, the area of the gas distribution plate 5 immediately below the loading tray 8 is protected from clogging with coal powder.

FIGS. 3A and 3B illustrate examples of the construction of the gas blow nozzle 13. In order to efficiently disperse the coal powder stream with the high temperature gas blown from the gas blow nozzle 13, an expanding nozzle may be used, as shown in FIG. 3A. Further, the same effect can be obtained by a plurality of gas blowing nozzles 13 spraying in different directions, as shown in FIG. 3B.

FIG. 4A is a cross-sectional view illustrating a preferred arrangement of the gas blower nozzle 13. FIG. 4B is a longitudinal sectional view illustrating a preferred arrangement of the blower nozzle 13.

The high temperature gas from the gas blower nozzle 13 blows the falling coal powder towards the discharge tray of the fluidized bed dryer 3 to disperse the coal powder stream. Here, the dividing wall 7 in the fluidized bed dryer 3 should be protected against wear when injected with coal powder. Thus, it is preferable that the ratio of the height H from the base of the gas blower nozzle 13 to the upper surface of the fluidized bed 9, the horizontal distance L from the gas blower nozzle 13 to the separation wall 7, the vertical angle θv and the horizontal angle θh of the gas blower 13 should correspond to the following inequality (1 ):

Here, when the fluidized bed dryer has one drying chamber and does not have a dividing wall, the above inequality (1) is calculated at L equal to the distance from the gas blower nozzle 13 to the inner wall of the fluidized bed dryer on the side of the discharge chute.

Second Embodiment

5A is a longitudinal sectional view illustrating a second embodiment of a fluidized bed dryer according to the present invention; Fig. 5B is a longitudinal sectional view II-II in Fig. 5A, illustrating a preferred arrangement of the gas nozzle; and FIGS. 5C and 5D show a sectional view III-III taken in FIG. 5A.

On Figa-5D, the exhaust gas of combustion (hereinafter referred to as "high temperature gas"), having a temperature of approximately 150-250 ° C, generated in a coke oven (not shown), is compressed by the compressor 1 and introduced into the blast chambers 4a and 4b, which located under the dryer 3 with a fluidized bed, through the gas line 2, as a heating and fluidizing gas. The high-temperature gas introduced into the blast chambers 4a, 4b passes upward through a gas distribution plate 5 located above the blast chambers 4a, 4b and is discharged through a gas exhaust line 6. The space in the dryer 3 with a fluidized bed is divided into two drying chambers, respectively. Further, in front of the blasting chamber 4a, the area immediately below the loading tray 8 is separated from other areas by the separation partition 14. In particular, as shown in FIGS. 5C-5D, the separation partition 14 is installed to separate the area directly below the loading tray 8 from the remaining areas .

The coal powder as wet feed is loaded into the fluidized bed dryer 3 through the loading tray 8 and forms a fluidized bed 9 on the gas distribution plate 5 by increasing the air flow by supplying high temperature gas through the gas distribution plate 5. The coal powder is dried in this fluidized bed 9 in this way to have a predetermined temperature and moisture content ratio, and is removed through the discharge tray 10.

The first bypass pipe 11 extends from the gas line 2, and through the first bypass pipe 11, a portion of the high temperature gas is introduced near the gas exhaust line 6 in the upper part of the fluidized bed dryer 3. The high temperature gas introduced into the first bypass pipe 11 prevents the formation of a condensation point around and downstream of the gas exhaust line 6.

Next, from the gas line 2, a second bypass line 12 passes through the second bypass line 12. High-temperature gas is introduced into the area directly below the loading tray, which is separated by a separation wall 14 in the blow chamber 4a, and high-temperature gas is introduced through the gas line 2 to other areas.

A flow control valve 15 is installed on the second bypass line 12, and a flow control valve 16 is installed below the branch point of the second bypass line 12.

With such a structure according to the present embodiment, the flow control valves 15, 16 mounted on the second bypass line 12 and the gas line 2 are controlled so as to provide a flow rate of the heating and fluidizing gas injected into the region immediately below the gas distribution plate 5 above the speed the flow of heating and fluidizing gas, blown into other areas that are not directly under the loading tray under the gas distribution plate. Accordingly, clogging rarely occurs in the area immediately below the loading chute 8 of the gas distribution plate 5, where clogging occurs mainly, so that the gas distribution plate 5 is protected from clogging.

According to the above-described embodiment, the flow rates of the high-temperature gas from the second bypass pipe 12 and the gas line 2 are controlled so as to provide a flow rate of the heating and fluidizing gas injected into the region immediately below the loading tray 8 under the gas distribution plate 5, higher; however, the diameters of the second bypass line 12 and the gas line 2 can be adjusted or a gas compression device can be installed on the second bypass line 12 in order to achieve the same goal.

Further, according to the task, high-temperature gas is introduced into the space directly under the loading tray 8 in the blasting chamber 4a from the second bypass pipe 12, leaving the gas line 2; however, an independent gas pipeline can be installed separately.

INDUSTRIAL APPLICABILITY

The present invention is applicable not only for drying coal powder for loading into a coke oven, but also for drying other wet materials such as granulated slag and limestone. In addition, the high-temperature gas used as a heating and fluidizing gas in a fluidized bed dryer is not limited to the exhaust gas of a coke oven combustion, but the exhaust gas of a flame furnace or a drying furnace can also be used here.

Claims (8)

1. The method of drying wet materials using a fluidized bed dryer for loading wet materials through the loading tray and blowing high-temperature gas from under the gas distribution plate as a heating and fluidizing gas in such a way as to form a fluidized bed on the gas distribution plate for drying the wet material, comprising blowing gas through a portion of the outer wall between the base of the loading tray and the fluidized bed to disperse the flow of wet raw materials falling from the load full-time tray. 2. The method of drying wet raw materials using the fluidized bed dryer of claim 1, wherein a portion of the high temperature gas is used as gas blown through a portion of the outer wall between the base of the loading tray and the fluidized bed. 3. A method of drying wet materials using a fluidized bed dryer for loading wet materials through a loading tray and blowing high-temperature gas from under the gas distribution plate as a heating and fluidizing gas so as to form a fluidized bed on the gas distribution plate for drying the wet material, including providing a flow rate of heating and fluidizing gas injected into the area directly below the loading tray from under the gas distribution plate greater than flow rate of heating and fluidizing gas injected into other areas from under the gas distribution plate. 4. A fluidized bed dryer for loading wet raw materials through a loading tray and blowing high-temperature gas from under a gas distribution plate as a heating and fluidizing gas so as to form a fluidized bed on a gas distribution plate for drying wet materials, containing a gas nozzle located on a a portion of the outer wall between the base of the loading tray and the fluidized bed to disperse the flow of moist raw materials falling from the loading tray. 5. The fluidized bed dryer of claim 4, further comprising a gas line for supplying a portion of the high temperature gas through a gas blower nozzle. 6. The fluidized bed dryer of claim 4, wherein the gas nozzle has an expanding mouth. 7. The fluidized bed dryer of claim 4, wherein the gas blower nozzle consists of a plurality of gas blower nozzles blowing gas in different directions. 8. A fluidized bed dryer for loading wet raw materials through a loading tray and blowing high temperature gas from under a gas distribution plate as a heating and fluidizing gas so as to form a fluidized bed on a gas distribution plate for drying wet materials in which the flow rate of the heating and fluidizing gas injected into the area immediately below the loading tray from under the gas distribution plate is provided higher than the flow rate of the heating and fluidizing gas by blowing to other areas from under the gas distribution plate.

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