Title of Invention

"A WET RAW MATERIAL DRYING METHOD AND A FLUIDIZED BED DRYER THEREOF"

Abstract A wet raw material drying method using a fluidized bed dryer for charging a wet raw material through a charging chute and blowing a high temperature gas from under a gas distribution plate as a heating and fluidizing gas so as to form a fluidized bed on the gas distribution plate to dry the wet raw material, the method comprising a step of: blowing a gas through a gas blowing nozzle disposed at an outer wall portion between a bottom of the charging chute and an upper face of the fluidized bed to disperse a flux of the wet raw material falling from the charging chute.
Full Text The present invention relates to a wet raw material drying method and a fluidized bed dryer thereof.
Technical Field
[0001] The. present invention relates to a fluidized bed dryer for drying a wet raw material such as coal charged into a coke oven and a. wet raw powder drying method using the fluidized bed dryer.
Background Art
[0002] When producing cokes, charging coal is dried prior to be charged into a coke oven for the purpose of improving the quality of cokes and productivity in the coke oven. Contained moisture in undried coke oven coals is approximately 9% to 13% in general, and the coals are dried with a coal dryer so as to contain moisture of 5% to 6%.
[0003] It is known to use a fluidized bed dryer for this coals drying. For example, according to a fluidized bed dryer disclosed in Patent Document 1, a wet raw material is charged on a gas distribution plate through a charging chute and a heating and fluidizing gas is blown from under the gas distribution plate so that a fluidized bed is formed on the gas distribution plate and the wet raw material is dried in the fluidized bed.
[0004] However, according to such a conventional
fluidized bed dryer, since the wet raw material is charged in an area of the fluidized bed on the gas distribution plate directly beneath the charging chute with a falling velocity, in the area directly beneath the charging chute, fine holes of the gas distribution plate are clogged with the thus charged wet raw material. This causes an incomplete drying due to a failure in fluidizations. Further, the clogged holes of the gas distribution plate are required to be patted to remove every clogs when the fluidized bed dryer is stopped to be repaired so that a huge amount of time and work is required. [0005] Patent Document 1: Japanese Patent Publication No. 2938029
Summary of the Invention
[0006] An object of the present invention is to prevent a gas distribution plate of a fluidized bed dryer from clogging with a wet raw material charged from a charging chute.
[0007] The present invention achieves the object by dispersing a flux of a wet raw material falling from a charging chute or by increasing a flow velocity of a heating and fluidizing gas blown to an area directly beneath the charging chute from under a gas distribution plate.
[0008] In other words, according to a first aspect of the present invention, when drying a wet raw material with a fluidized bed dryer for charging the

wet raw material through a charging chute and blowing a high temperature gas as a heating and fluidizing gas from under a distribution plate so as to form a fluidized bed on the gas distribution plate to dry the wet raw material, a gas is blown from a gas blowing nozzle provided at an outer wall portion between a bottom of the charging chute and the fluidized bed to disperse a flux of the wet raw material falling from the charging chute. [0009] In the first aspect, some of said high temperature gas can be used as the gas blown from the gas blowing nozzle.
[0010] According to a second aspect of the present invention, when drying a wet raw material with a fluidized bed dryer for charging the wet raw material through a charging chute and blowing a high temperature gas as a heating and fluidizing gas from under a distribution plate so as to form a fluidized bed on the gas distribution plate to dry the wet raw material, a flow velocity of the heating and fluidizing gas blown to an area directly beneath a charging chute from under the gas distribution plate is provided faster than a flow velocity of the heating and fluidizing gas blown to other areas where is not directly beneath the charging chute from under the gas distribution plate.
[0011] According to the present invention, the flux of the wet raw material falling from the charging chute is dispersed so that the wet raw material
falling from the charging chute does not fall intensively to a particular area directly beneath the charging chute and the gas distribution plate is prevented from clogging.
[0012] Further, according to the present invention, the flow velocity of the heating and fluidizing gas blown to the area directly beneath the charging chute from under the gas distribution plate is made faster so that the clogging hardly occurs at the area of the gas distribution plate directly beneath the charging chute where clogging often occurs in general and the gas distribution plate is prevented from clogging.
Brief Description of the Drawings

[0013] Fig. 1A is a longitudinal showing a first embodiment of a f!

sectional view uidized bed dryer

of the present invention;
Fig. IB is a sectional view taken along I-I line in Fig. 1A;
Fig. 2 is a schematic view showing a blowing condition of a high temperature gas by a gas blowing nozzle;
Fig. 3A is a view showing a structure of the gas blowing nozzle;
Fig. 3B is a view showing a structure of the gas blowing nozzle;
Fig. 4A is a transverse sectional view showing a preferable arrangement of the gas blowing nozzle;
Fig. 4B is a longitudinal sectional view showing

the preferable arrangement of the gas blowing nozzle;
Fig. 5A is a longitudinal sectional view showing a second embodiment of the fluidized bed dryer of the present invention;
Fig. 5B is a sectional view taken along II-II line in Fig. 5 A;
Fig. 5C is a sectional view taken along Ill-Ill line in Fig. 5A; and
Fig. 5D is a sectional view taken along III-III line in another example of Fig. 5A.
Detailed Description of the Preferred Embodiments
[0014] Embodiments of the present invention will be described based on embodiments of applying the present invention to drying of coal powder for a coke oven (hereinafter simply referred to as "coal powder").
-First Embodiment-Fig. 1A is a longitudinal sectional view showing a first embodiment of a fluidized bed dryer of the present invention and Fig. IB is a sectional view taken along I-I line in Fig. 1A.
[0015] As shown in Figs. 1A and IB, an exhaust combustion gas (hereinafter referred to as "high temperature gas") having a temperature of approximately 150°C to 250°C generated in a coke oven (not shown) is pressurized by a blower 1 and introduced into wind boxes 4a, 4b, which are located under a fluidized bed dryer 3, via a gas main 2 as a
heating and fluidizing gas. The high temperature gas introduced in the wind boxes 4a, 4b moves upward through a gas distribution plate 5 disposed above the wind boxes 4a, 4b and is discharged from a gas outlet 6. A space in the fluidized bed dryer 3 is divided into two drying chambers 3a, 3b by a partition wall 7 and the wind boxes 4a, 4b are disposed under the drying chambers, respectively.
[0016] Coal powder as a wet raw material is charged into the fluidized bed dryer 3 through a charging chute 8, and forms a fluidized bed 9 on the gas distribution plate 5 by a rising air current due to the high temperature gas passing through the gas distribution plate 5. The coal powder is dried in this fluidized bed 9 so as to have a predetermined temperature and a contained moisture ratio and is discharged from a discharging chute 10.
[0017] A first bypass pipe 11 is branched from the gas main 2, and via this first bypass pipe 11, some of the high temperature gas is introduced into a vicinity of the gas outlet 6 in an upper part of the fluidized bed dryer 3. The high temperature gas introduced from the first bypass pipe 11 prevents a generation of dew condensation around and in the downstream of the gas outlet 6.
[0018] Further, from the first bypass pipe 11, a second bypass pipe 12 is branched and, via this second bypass pipe 12, some of the high temperature gas is blown to the gas blowing nozzle 13. The gas
blowing nozzle 13 is disposed at an outer wall portion 3c between a bottom of the charging chute 8 and above the fluidized bed 9 and via the gas blowing nozzle 13, some of the high temperature gas is blown into the fluidized bed dryer 3. Here, the second bypass pipe 12 may be branched from the gas main 2.
[0019] Fig. 2 schematically shows a blowing condition of the high temperature gas by a gas blowing nozzle 13. As shown in Fig. 2, the high temperature gas blown from the gas blowing nozzle 13 disperses a flux of the coal powder (wet raw material) so that the coal powder falling from the charging chute 8 does not fall intensively to an area directly beneath the charging chute 8. With this structure, the area of the gas distribution plate 5 directly beneath the charging chute 8 is prevented from clogging with the coal powder.
[0020] Figs. 3A and 3B show examples of structure of the gas blowing nozzle 13. In order to disperse the flux of the coal powder efficiently with a high temperature gas blown from the gas blowing nozzle 13, the gas blowing nozzle 13 having a splayed-out opening can be employed, as shown in Fig. 3A. Further, the same effect can be obtained with a plurality of gas blowing nozzles 13 blowing in different directions, as shown in Fig. 3B.
[0021] Fig. 4A is a transverse sectional view showing a preferable arrangement of the gas blowing nozzle 13. Fig. 4B is a longitudinal sectional view
showing the preferable arrangement of the gas blowing no z zle 13.
[0022] The high temperature gas from the gas blowing nozzle 13 blows the falling coal powder toward a discharging chute of the fluidized bed dryer 3 to disperses the flux of the coal powder. Here, the partition wall 7 in the fluidized bed dryer 3 should be prevented from getting worn by hitting of the blown coal powder. Thus, preferably, the relation of a height H from the bottom of the gas blowing nozzle 13 to the upper face of the fluidized bed 9, a horizontal distance L from the gas blowing nozzle 13 to the partition wall 7, a vertical angle 9v and a horizontal angle 6h of the gas blowing nozzle 13 is set to meet the relation of the following eguation (1):
tan0v>H/ (L/cosGh) (1)
[0023] Here, when the fluidized bed dryer has a single drying chamber and does not have a partition wall, the above equation (I) is calculated as the L is set to a horizontal distance from the gas blowing nozzle 13 to the inner wall of the fluidized bed dryer at the side of the discharging chute.
[0024]
-Second Embodiment-Fig. 5A is a longitudinal sectional view showing a second embodiment of the fluidized bed dryer of the present invention; Fig. 5B is a sectional view taken along 11 -11 line in Fig. 5 A; and Figs. 5C and 5D are
sectional views taken along Ill-Ill in Fig. 5A. [0025] In Figs. 5A to 5D, an exhaust combustion gas (hereinafter referred to as "high temperature gas") having a temperature of approximately 150°C to 250°C generated in a coke oven (not shown) is pressurized by a blower 1 and introduced into wind boxes 4a, 4b, which are located under a fluidized bed dryer 3, via a gas main 2 as a heating and fluidizing gas. The high temperature gas introduced in the wind boxes 4a, 4b moves upward through a gas distribution plate 5 disposed above the wind boxes 4a, 4b and is discharged from a gas outlet 6. A space in the fluidized bed dryer 3 is divided into two drying chambers 3a, 3b by a partition wall 7 and the wind boxes 4a, 4b are disposed under the drying chambers, respectively. Further, in the prior wind box 4a, an area directly beneath the charging chute 8 is separated from other areas by a partition wall 14. Concretely, as shown in Fig. 5C or 5D, the partition wall 14 is placed to separate the area directly beneath the charging chute 8 from other areas.
[0026] Coal powder as a wet raw material is charged into the fluidized bed dryer 3 through a charging chute 8, and forms a fluidized bed 9 on the gas distribution plate 5 by a rising air current due to the high temperature gas passing through the gas distribution plate 5. The coal powder is dried in this fluidized bed 9 so as to have a predetermined temperature and a contained moisture ratio and is
discharged by a discharging chute 10.
[0027] A first bypass pipe 11 is branched from the gas main 2, and via this first bypass pipe 11, some of the high temperature gas is introduced into a vicinity of the gas outlet 6 in an upper part of the fluidized bed dryer 3. The high temperature gas introduced from the first bypass pipe 11 prevents a generation of dew condensation around and in the downstream of the gas outlet 6.
[0028] Further, from the gas main 2, a second bypass pipe 12 is branched. The second bypass pipe 12 introduces high temperature gas to the area directly beneath the charging chute 8, which is separated by the partition wall 14 in the wind box 4a and the gas main 2 introduces the high temperature gas to the other areas.
[0029] A flow adjusting valve 15 is provided at the second bypass pipe 12 and a flow adjusting valve 16 is provided in a downstream of the branch point of the second bypass pipe 12.
[0030] With such a structure, according to the present embodiment, the flow adjusting valves 15, 16 provided to the second bypass pipe 12 and the gas main 2 are adjusted so that a flow velocity of the heating and fluidizing gas blown to the area directly beneath the charging chute 8 from under the gas distribution plate 5 is made faster than a flow velocity of the heating and fluidizing gas blown to other areas where is not directly beneath the
charging chute from under the gas distribution plate. Accordingly, clogging hardly occurs at the area directly beneath the charging chute 8 of the gas distribution plate 5 where clogging often occurs in general so that the gas distribution plate 5 is prevented from clogging.
[0031] According to the above embodiment, flow rates of the high temperature gas from the second bypass pipe 12 and gas main 2 are adjusted to make the flow velocity of heating and fluidizing gas blown to the area directly beneath the charging chute 8 from under the gas distribution plate 5 faster; however, diameters of the second bypass pipe 12 and the gas main 2 may be adjusted or a gas pressurization device may be provided to the second bypass pipe 12, in order to achieve the same object. [0032] Further, according to the above object, the high temperature gas is introduced to the area directly beneath the charging chute 8 in the wind box 4a from the second bypass pipe 12 branched from the as main 2; however, an independent gas pipe may be provided separately.
Industrial Applicability
[0033] The present invention is applicable not only to drying of coal powder to be charged into a coke oven, but also to drying of other wet raw materials such as granulated slag and limestone. Further, the high temperature gas used as a heating and fluidizing
gas of a fluidized bed dryer is not limited to the
exhaust combustion gas of a coke oven, where an
exhaust gas from a combustion furnace or a kiln can
also be used.
























WE CLAIM:
1. A wet raw material drying method using a fluidized bed dryer for charging a wet raw
material through a charging chute and blowing a high temperature gas from under a gas
distribution plate as a heating and fluidizing gas so as to form a fluidized bed on the gas
distribution plate to dry the wet raw material, the method comprising a step of:
blowing a gas through a gas blowing nozzle disposed at an outer wall portion between a bottom of the charging chute and an upper face of the fluidized bed to disperse a flux of the wet raw material falling from the charging chute.
2. The wet raw material drying method using the fluidized bed dryer as claimed in claim 1,
wherein some of said high temperature gas is used as the gas blown through the gas blowing
nozzle disposed at the outer wall portion between the bottom of the charging chute and the
fluidized bed.
3. A fluidized bed dryer for charging a wet raw material through a charging chute and
' blowing a high temperature gas from under a gas distribution plate as a heating and fluidizing
gas so as to form a fluidized bed on the gas distribution plate to dry the wet raw material, the fluidized bed dryer comprising:
a gas blowing nozzle disposed at an outer wall portion between a bottom of the charging chute and an upper face of the fluidized bed, for blowing a gas to disperse a flux of the wet raw material falling from the charging chute.
4. The fluidized bed dryer as claimed in claim 4, further comprising:
a gas pipe introducing some of said high temperature gas to the gas blowing nozzle.
5. The fluidized bed dryer as claimed in claim 4, wherein the gas blowing nozzle has a
splayed-out opening.
6. The fluidized bed dryer as claimed in claim 4, wherein the gas blowing nozzle is composed of a plurality of gas blowing nozzles blowing the gas in different directions.


Documents:

7554-DELNP-2007-Abstract-(29-06-2011).pdf

7554-delnp-2007-abstract.pdf

7554-delnp-2007-Claims-29-06-2011.pdf

7554-delnp-2007-claims.pdf

7554-DELNP-2007-Correspondence Others-(29-06-2011).pdf

7554-delnp-2007-correspondence-others 1.pdf

7554-DELNP-2007-Correspondence-Others-(13-05-2011).pdf

7554-DELNP-2007-Correspondence-Others-(31-12-2010).pdf

7554-delnp-2007-correspondence-others.pdf

7554-DELNP-2007-Description (Complete)-(29-06-2011).pdf

7554-delnp-2007-description (complete).pdf

7554-DELNP-2007-Drawings-(29-06-2011).pdf

7554-delnp-2007-drawings.pdf

7554-DELNP-2007-Form-1-(29-06-2011).pdf

7554-delnp-2007-form-1.pdf

7554-delnp-2007-form-18.pdf

7554-DELNP-2007-Form-2-(29-06-2011).pdf

7554-delnp-2007-form-2.pdf

7554-DELNP-2007-Form-3-(13-05-2011).pdf

7554-DELNP-2007-Form-3-(29-06-2011).pdf

7554-DELNP-2007-Form-3-(31-12-2010).pdf

7554-delnp-2007-form-3.pdf

7554-delnp-2007-form-5.pdf

7554-DELNP-2007-GPA-(29-06-2011).pdf

7554-delnp-2007-pct-301.pdf

7554-delnp-2007-pct-304.pdf

7554-DELNP-2007-PCT-306.pdf

7554-delnp-2007-pct-308.pdf

7554-DELNP-2007-Petition-137-(13-05-2011).pdf


Patent Number 250787
Indian Patent Application Number 7554/DELNP/2007
PG Journal Number 05/2012
Publication Date 03-Feb-2012
Grant Date 27-Jan-2012
Date of Filing 03-Oct-2007
Name of Patentee NIPPON STEEL ENGINEERING CO., LTD.
Applicant Address LOCATED AT 6-3, OTEMACHI 2-CHOME, CHIYODA-KU, TOKYO 100-8071, JAPAN,
Inventors:
# Inventor's Name Inventor's Address
1 UDAI KANEKO C/O NIPPON STEEL ENGINEERING CO ., LTD., 46- 59, OAZA-NAKABARU, TOBATA-KU, KITAKYUSHU-SHI, FUKUOKA 804-8505, JAPAN,
2 ATSUSHI FUJIKAWA C/O NIPPON STEEL ENGINEERING CO ., LTD., 46- 59, OAZA-NAKABARU, TOBATA-KU, KITAKYUSHU-SHI, FUKUOKA 804-8505, JAPAN,
3 KAZUSHI KISHIGAMI C/O NIPPON STEEL ENGINEERING CO ., LTD., 46- 59, OAZA-NAKABARU, TOBATA-KU, KITAKYUSHU-SHI, FUKUOKA 804-8505, JAPAN,
PCT International Classification Number F26B 3/08
PCT International Application Number PCT/JP2006/307131
PCT International Filing date 2006-04-04
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 2005-112598 2005-04-08 Japan