Title of Invention	"A WET RAW MATERIAL DRYING METHOD AND AN APPARATUS THEREOF"
Abstract	A wet raw material drying method for drying a wet raw material charged into a coke over by introducing a high temperature gas into a fluidized bed dryer as a heat source and a fluidizing gas, the method comprising blowing a part of the high temperature gas, using a plurality of blowing nozzles, into an inside of a charging chute which charges the wet raw material into the fluidized bed dryer.

Full Text

DESCRIPTION WET RAW MATERIAL DRYING METHOD AND APPARATUS Technical Field [0001] The present invention relates to a method and apparatus for drying a wet raw material such as coal to be charged into a coke oven, with a fluidized bed dryer. Background Art [0002] When producing cokes, drying of coal charges is performed before charging into a coke oven for the purpose of improving the guality of cokes and improving productivity in the coke oven. Contained moisture in coals for a coke oven is approximately 9% to 13% in general before drying, but the coals are dried to have moisture of 5% to 6% by a coal dryer. [0003] It is conventionally known to use a fluidized bed dryer for this drying of coals, and Patent document 1 discloses a method of drying coals by introducing a flue exhaust gas of a coke oven as a heat source and a fluidizing gas into the fluidized bed dryer. [0004] Also, Patent document 2 discloses a method of introducing a part of an exhaust gas, which is introduced into a lower part of the fluidized bed dryer, into a vicinity of a gas outlet of the fluidized bed dryer, so as to prevent generation of dew condensation in the vicinity of the gas outlet of the fluidized bed dryer and the downstream side thereof when drying a wet raw material by introducing the exhaust gas as a heat source and a fluidizing gas into the fluidized bed dryer. [0005] However, in these wet raw material drying methods with the fluidized bed dryer, the wet raw material is charged into the fluidized bed dryer by means of a charging chute, and hence adhesion or deposition of the wet raw material occurs in the charging chute particularly in a side end portion (corner), which has been a cause for a charging problem. Particularly, when a contained moisture ratio in the wet raw material is high at the time of raining or the like, the adhesion to or deposition on the charging chute is significant. Moreover, when the air temperature largely drops in a cold district, a wet raw material adhered to or deposited on the charging chute freezes up, thereby worsening the charging problem. [0006] Accordingly, there is a method to prevent adhesion or deposition of a wet raw material by heating the charging chute by means of indirect heating with a heat medium such as vapor, but in this method an expensive apparatus for heating is necessary, and simultaneously, a running cost for the heat medium such as vapor is needed. As another method, it is conceivable to perform hammering from the outside of the charging chute by man power or by compressed air vibrations, but this method also requires a running cost for heavy works or for compressed air. [0007] Patent document 1: Japanese Patent Application Laid-open No. 2001-55582 Patent Document 2: Japanese Patent No. 2807813 Summary of the Invention [0008] An object to be solved by the present invention is to enable, in a method and an apparatus for drying a wet raw material with a fluidized bed dryer, prevention of a wet raw material from adhering to or deposited on a charging chute of the fluidized bed dryer at a low cost with a simple structure. [0009] A wet raw material drying method of the present invention for drying a wet raw material such as coal charged into a coke oven by introducing a high temperature gas into a fluidized bed dryer as a heat source and a fluidizing gas is characterized by including blowing a part of the high temperature gas into an inside of a charging chute which charges the wet raw material into the fluidized bed dryer. [0010] Further, a wet raw material drying apparatus of the present invention for drying a wet raw material such as coal charged into a coke oven by introducing a high temperature gas into a fluidized bed dryer as a heat source and a fluidizing gas is characterized by including a blowing nozzle blowing a part of the high temperature gas toward an inside of a charging chute which charges the wet raw material into the fluidized bed dryer. [0011] In the drying method and apparatus of the present invention, the part of the high temperature gas may be blown toward a side end portion inside the charging chute. [0012] Further, the part of the high temperature gas may be blown toward the inside of the charging chute from an upstream side of the charging chute. [0013] Further, the part of the high temperature gas may be blown into the inside of the charging chute and may be also introduced into a vicinity of a gas outlet of the fluidized bed dryer, and a high temperature gas blowing amount into the inside of the charging chute and a high temperature gas introducing amount into the vicinity of the gas outlet of the fluidized bed dryer may be controlled so that a gas temperature in the vicinity of the gas outlet of the fluidized bed dryer becomes egual to or higher than a dew point. [0014] In the present invention, since a part of the high temperature gas used as a heat source and a fluidizing gas for the fluidized bed dryer is blown into the inside of the charging chute, it is not necessary to have a heating device or the like of an indirect heating method by means of a heat medium such as vapor, which is arranged conventionally for preventing adhesion or deposition of wet raw material Therefore, the structure of the apparatus becomes simple, and costs thereof can be reduced. [0015] Further, since the present invention is of a direct heating method to blow a part of the high temperature gas into the inside of the charging chute, it is possible to securely prevent a wet raw material from adhering to or deposited on the inside of the charging chute as compared to the conventional indirect heating method. Further, it is also possible to prevent freezing of a wet raw material in a cold district. [0016] Additionally, it becomes possible to reduce the diameter of a gas pipe which conventionally leads a high temperature gas to the vicinity of a gas outlet in an upper part of the fluidized bed dryer for preventing dew condensation, or to eliminate the gas pipe. Brief Description of the Drawings [0017] Fig. 1 is a schematic structure view showing a first embodiment of a drying apparatus of the present invention; Fig. 2A is a front view showing a structure example for blowing a high temperature gas into the inside of a charging chute in the structure of Fig. 1; Fig. 2B is a view taken along the A-A line in Fig. 2A; Fig. 3A is a perspective view showing an arrangement example of blowing nozzles which blow the high temperature gas into the inside of the charging chute in the structure of Fig. 2A, Fig. 2B; Fig. 3B is a front view showing the arrangement example of the blowing nozzles which blow the high temperature gas into the inside of the charging chute in the structure of Fig. 2A, Fig. 2B; Fig. 3C is a side view showing the arrangement example of the blowing nozzles which blow the high temperature gas into the inside of the charging chute in the structure of Fig. 2A, Fig. 2B; Fig. 4A is a perspective view showing an arrangement example of blowing nozzles which blow the high temperature gas into the inside of the charging chute in the structure of Fig. 2A, Fig. 2B; Fig. 4B is a front view showing the arrangement example of the blowing nozzles which blow the high temperature gas into the inside of the charging chute in the structure of Fig. 2A, Fig. 2B; Fig. 4C is a side view showing the arrangement example of the blowing nozzles which blow the high temperature gas into the inside of the charging chute in the structure of Fig. 2A, Fig. 2B; Fig. 5A is a front view showing another structure example for blowing the high temperature gas into the inside of the charging chute; Fig. 5B is a view taken along the B-B line in Fig. 5A; Fig. 6A is a perspective view showing an arrangement example of blowing nozzles which blow the high temperature gas into the inside of the charging chute in the structure of Fig. 5A, Fig. 5B; Fig. 6B is a side view showing the arrangement example of the blowing nozzles which blow the high temperature gas into the inside of the charging chute in the structure of Fig. 5A, Fig. 5B; Fig. 7 is a schematic structure view showing a second embodiment of a drying apparatus of the present invention; and Fig. 8 is a schematic structure view showing a third embodiment of a drying apparatus of the present invention. Detailed Description of the Preferred Embodiments [0018] Hereinafter, embodiments of the present invention will be described based on embodiments of applying the present invention to drying of pulverized coal for a coke oven (hereinafter simply referred to as "pulverized coal") . [0019] -First Embodiment-Fig. 1 is a schematic structure view showing a first embodiment of a drying apparatus of the present invention. In this view, 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 forcing fan 1, introduced from a lower part of a fluidized bed dryer 4 via a gas main 2 and a flow adjusting valve 3 and discharged from a gas outlet 5 in an upper part. [0020] Pulverized coal as a wet raw material is charged into the fluidized bed dryer 4 through a charging chute 6, and forms a fluidized bed 7 by a rising gas current due to the aforementioned high temperature gas introduced from the lower part of the fluidized bed dryer 4. In this fluidized bed 7, drying of the pulverized coal is performed, and the pulverized coal is adjusted to have a predetermined temperature and a contained moisture ratio, and is discharged through a discharging chute 8. [0021] A first bypass pipe 9 is branched from the gas main 2, and via this first bypass pipe 9, a part of the high temperature gas is introduced into a vicinity of the gas outlet 5 in the upper part of the fluidized bed dryer 4. Further, from the first bypass pipe 9, a second bypass pipe 11 is branched from a downstream side of a flow adjusting valve 10 provided in the middle thereof, and via this second bypass pipe 11, a part of the high temperature gas is blown into the inside of the charging chute 6. As a method of adjusting a gas amount distributed to the second bypass pipe 11 out of the high temperature gas introduced from the first bypass pipe 9, there are conceivable a method of providing a flow adjusting valve or an orifice in the middle of the second bypass pipe 11, a method of providing a flow adjusting valve or an orifice on the downstream side of a branching part of the first bypass pipe 9 to the second bypass pipe 11, and further the both of them. [0022] The gas discharged from the gas outlet 5 in the upper part of the fluidized bed dryer 4 is induced by an inducing fan 14 to flow in a gas exhaust pipe 12, and is exhausted to the atmosphere after removal of dust by a dust collector 13 such as a bag filter. [0023] As above, in the present invention, it is possible to prevent the pulverize-d coal from adhering to or deposited on the inside of the charging chute 6 by blowing the part of the high temperature gas into the inside of the charging chute 6. [0024] Further, the high temperature gas blown into the inside of the charging chute 6 and the high temperature gas introduced into the vicinity of the gas outlet 5 remain at a high temperature since they do not pass the fluidized bed 7 which includes dried material. By controlling these high temperature gas amounts, a gas temperature in the vicinity of the gas outlet 5 can be made equal to or higher than a dew point, and thereby occurrence of dew condensation in the vicinity of the gas outlet 5 and on the downstream side thereof can be prevented. In this embodiment, as described above, the second bypass pipe 11 is branched on the downstream side of the flow adjusting valve 10 of the first bypass pipe 9, a total high temperature gas amount which does not pass the fluidized bed 7 can be adjusted by the flow adjusting valve 10 so that the gas temperature in the vicinity of the gas outlet 5 becomes equal to or higher than the dew point. Further, by branching the second bypass pipe 11 on the downstream side of the flow adjusting valve 10 of the first bypass pipe 9, a pipe length of the second bypass pipe 11 to the charging chute 6 can be made short. [0025] Note that in the case where the temperature of the high temperature gas is insufficient, a heating device may be provided on the upstream side of the branching part of the first bypass pipe 9 of the gas main 2 so as to heat the gas. [0026] Fig 2A is a front view showing a structure example for blowing a high temperature gas into the inside of the charging chute, and Fig. 2B is a view taken along the A-A line in Fig. 2A. Fig. 3A to Fig. 3C, Fig. 4A to Fig. 4C respectively show arrangement examples of blowing nozzles which blow the high temperature gas into the inside of the charging chute in the structure of Fig. 2A, Fig. 2B. [0027] The example shown in Fig. 2A and Fig. 2B is arranged to blow the high temperature gas toward side end portions (corners) inside the charging chute 6, where the pulverized coal easily deposits. Specifically, as shown in Fig. 3A to Fig. 3C or Fig. 4A to Fig. 4C, a plurality of blowing nozzles 15 are provided on a sliding surface 6a or side surfaces 6b of the charging chute 6 so that the blowing directions of the blowing nozzles 15 are directed to side end portions 6c of the charging chute 6. At this time, by appropriately adjusting angles 91, 62 shown in Fig. 4B, Fig. 4C, adhesion of the pulverized coal to the side end portions 6c of the charging chute 6 can be prevented securely. Further, it is preferable that positions of the blowing nozzles 15 are such that LI, L2 shown in Fig. 3B, Fig. 3C are made as small as possible. Furthermore, the blowing nozzles 15 arranged on the sliding surface 6a of the charging chute 6 are needed to have angles so that the pulverized coal falling in the charging chute 6 do not block nozzle holes thereof, where it is preferable that angles of the blowing nozzles 15 are set so that 90° - (0c + 6n) in Fig. 4C become larger than repose angles for the pulverized coal. [0028] Note that considering heating and drying for preventing adhesion of the pulverized coal to the charging chute 6, it is preferable that the temperature of the high temperature gas to be blown into the charging chute 6 is higher than the ambient temperature. Further, considering heat resistance of the charging chute 6 generally made of an ordinary steel plate, it is preferable that the temperature of the high temperature gas to be blown is 350°C or lower It is preferable that the humidity of the high temperature gas to be blown is as low as possible. [0029] Fig. 5A is a front view showing another structure example of blowing the high temperature gas into the inside of the charging chute, and Fig. 5B is a view taken along the B-B line in Fig. 5A. Fig. 6A, Fig. 6B show an arrangement example of blowing nozzles which blow the high temperature gas into the inside of the charging chute in the structure of Fig. 5A, Fig. 5B. [0030] The example shown in Fig. 5A, Fig. 5B is arranged to blow the high temperature gas from a charging device 16 on the upstream side of the charging chute 6 toward the inside of the charging chute 6 so as to heat and dry the entire charging chute 6. Specifically, as shown in Fig. 6A, Fig. 6B, the blowing nozzles 15 are arranged on the charging device 16 so as to blow the high temperature gas into the inside of the charging chute 6. At this time, it is preferable that angles 0p of the blowing nozzles 15 in Fig. 6B are between 0° and 0c so that the pulverized coal charged into the fluidized bed through the charging chute 6 from the charging device 16 can fall smoothly. Further, it is preferable that the position of a lower end surface N of the blowing nozzles 15 opposite to the fluidized bed is located more inward (on the fluidized bed side) in the charging chute 6 than the position of the upper end surface C of the sliding surface 6a of the charging chute 6. [0031] -Second Embodiment-Fig. 7 is a schematic structure view showing a second embodiment of a drying apparatus of the present invention. Note that the same components as those in the first embodiment shown in Fig. 1 are designated the same symbols, and explanations thereof are omitted. [0032] In the first embodiment shown in Fig. 1, the second bypass pipe 11 for blowing the part of the high temperature gas into the charging chute 6 is branched from the first bypass pipe 9, but in this embodiment, the second bypass pipe 11 is branched from the gas main 2, and a flow adjusting valve 17 is provided also on the second bypass pipe 11. [0033] In this embodiment, by just coupling the second bypass pipe 11 to the gas main 2, the high temperature gas pressurized by the forcing fan 1 can be blown into the inside of the charging chute 6. [0034] Further, in this embodiment, a control device 18 is connected to the flow adjusting valve 10 of the first bypass pipe 9 and the flow adjusting valve 17 of the second bypass pipe 11, thereby enabling detection and adjustment of high temperature gas flow rates in the first bypass pipe 9 and the second bypass pipe 11. Accordingly, a total high temperature gas amount that does not pass the fluidized bed 7 can be adjusted, and the gas temperature in the vicinity of the gas outlet 5 is made to be equal to or higher than the dew point. Further, as compared to conventional cases where a high temperature gas is introduced by one gas pipe (first bypass pipe 9) into the vicinity of the gas outlet 5, introducing of the high temperature gas also from the second bypass pipe 11 in this manner makes it possible to reduce the diameter of the gas pipe thereof or eliminate the gas pipe. [0035] -Third Embodiment-Fig. 8 is a schematic structure view showing a third embodiment of a dryer apparatus of the present invention. Note that the same components as those in the first embodiment shown in Fig. 1 are designated the same symbols, and explanations thereof are omitted. [0036] In this embodiment, in addition to the high temperature gas or instead of the high temperature gas, a dry gas such as instrumented air is blown into the charging chute 6. However, when using the instrumented air, it cannot be regarded as efficient in view of a low temperature and a running cost for the instrumented air. Also, blowing a gas containing a large amount of oxygen results in increase of oxygen concentration in the fluidized bed dryer 4, and therefore the blowing amount needs to be adjusted so that the oxygen concentration in the fluidized bed dryer 4 fall within a safe range in consideration of preventing dust explosion or the like when blowing. Industrial Applicability [0037] The present invention is applicable not only to drying of pulverized coal 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 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 for drying a wet raw material charged into a coke oven by introducing a high temperature gas into a fluidized bed dryer as a heat source and a fiuidizing gas, the method comprising: blowing a part of the high temperature gas, using a plurality of blowing nozzles, into an inside of a charging chute which charges the wet raw material into the fluidized bed dryer. 2. The wet raw material drying method as claimed in claim 1, wherein the part of the high temperature gas is blown toward a side end portion inside the charging chute. 3. The wet raw material drying method as claimed in claim 1, wherein the part of the high temperature gas is blown toward the inside of the charging chute from an upstream side of the charging chute. 4. The wet raw material drying method as claimed in claim 1, wherein the part of the high temperature gas is blown into the inside of the charging chute and is also introduced into a vicinity of a gas outlet of the fluidized bed dryer, and a high temperature gas blowing amount into the inside of the charging chute and a high temperature gas introducing amount into the vicinity of the gas outlet of the fluidized bed dryer are controlled so that a gas temperature in the vicinity of the gas outlet of the fluidized bed dryer becomes equal to or higher than a dew point. 5. A wet raw material drying apparatus for drying a wet raw material charged into a coke oven by introducing a high temperature gas into a fluidized bed dryer as a heat source and a fiuidizing gas, the apparatus comprising a plurality of blowing nozzles blowing a part of the high temperature gas toward an inside of a charging chute which charges the wet raw material into the fluidized bed dryer. 6. The wet raw material drying apparatus as claimed in claim 5, wherein said blowing nozzle is arranged so that a blowing direction of said blowing nozzle is directed to a side end portion inside the charging chute. 7. The wet raw material drying apparatus as claimed in claim 5, wherein said blowing nozzle is arranged on an upstream side of the charging chute so that a blowing direction of said blowing nozzle is directed to the inside of the charging chute. 8. The wet raw material drying apparatus as claimed in claim 5, having a gas pipe introducing the part of the high temperature gas into a vicinity of a gas outlet of the fluidized bed dryer; and a control device controlling a high temperature gas blowing amount into the inside of the charging chute and a high temperature gas introducing amount into the vicinity of the gas outlet of the fluidized bed dryer so that a gas temperature in the vicinity of the gas outlet of the fluidized bed dryer becomes equal to or higher than a dew point.

Documents:

7012-DELNP-2007-Abstract-(08-08-2011).pdf

7012-delnp-2007-abstract.pdf

7012-DELNP-2007-Claims-(08-08-2011).pdf

7012-delnp-2007-claims.pdf

7012-DELNP-2007-Correspondence Others-(08-08-2011).pdf

7012-delnp-2007-correspondence-others 1.pdf

7012-DELNP-2007-Correspondence-Others.pdf

7012-delnp-2007-description (complete).pdf

7012-DELNP-2007-Drawings-(08-08-2011).pdf

7012-delnp-2007-drawings.pdf

7012-DELNP-2007-Form-1-(08-08-2011).pdf

7012-DELNP-2007-Form-1.pdf

7012-delnp-2007-form-18.pdf

7012-DELNP-2007-Form-2-(08-08-2011).pdf

7012-delnp-2007-form-2.pdf

7012-DELNP-2007-Form-3-(08-08-2011).pdf

7012-delnp-2007-form-3.pdf

7012-delnp-2007-form-5.pdf

7012-DELNP-2007-GPA-(08-08-2011).pdf

7012-delnp-2007-gpa.pdf

7012-delnp-2007-pct-237.pdf

7012-delnp-2007-pct-301.pdf

7012-delnp-2007-pct-304.pdf

7012-delnp-2007-pct-306.pdf

7012-DELNP-2007-PCT-308.pdf

7012-delnp-2007-pct-338.pdf

7012-delnp-2007-pct-373.pdf