AU2013200919A1 - Fluid bed drying apparatus, gasification combined power generating facility, and drying method - Google Patents

Abstract

Abstract Provided are a fluid bed drying apparatus including: a drying furnace which forms a fluid bed therein in a manner such that a wet fuel supplied thereto flows in a flow direction by a fluidizing gas; a fuel input port provided in the drying furnace at the upstream side in the flow direction for inputting the wet fuel into the drying furnace; a fuel discharge port provided in the drying furnace at the downstream side in the flow direction for discharging the wet fuel dried inside the drying furnace; and a reverse flow supply portion provided inside the fluid bed for supplying the wet fuel so that the wet fuel is made to reversely flow from the downstream side in the flow direction toward the upstream side therein. FLUID BED DRYING APPARATUS BROWN DRYING FURNACE 42 EXHAUST GAS ~.......... GAS 1 FLUIDIZING GAS DRY COAL

Description

1 FLUID BED DRYING APPARATUS, GASIFICATION COMBINED POWER GENERATING FACILITY, AND DRYING METHOD CROSS-REFERENCE TO RELATED APPLICATIONS This application is based upon and claims the benefit of priority from Japanese Patent Application No. 2012 034323 filed February 20, 2012, the entire contents of which are incorporated herein by reference. BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid bed drying apparatus, a gasification combined power generating facility, and a drying method of drying a wet fuel such as brown coal in a flowing state. 2. Description of the Related Art As a fluid bed drying apparatus, there is conventionally known an agitating heat transfer type fluidized drying apparatus including a dryer body, a planar porous plate which defines the inside of the dryer body into an upper fluidizing chamber and a lower wind box, and a partition wall which'defines the fluidizing chamber into a front fluidizing chamber and a rear fluidizing chamber (for example, see Japanese Laid-open Patent Publication No. 4-13086). In the agitating heat transfer type fluidized drying apparatus, the front fluidizing chamber is provided with a hollow rotary shaft which is disposed in the longitudinal direction and an agitating heat transfer member which is attached to a hollow rotary shaft, and a material supplied to the front fluidizing chamber is mixed and heated in a manner such that the agitating heat transfer member rotates about the hollow rotary shaft. Incidentally, in the fluid bed drying apparatus which 2 heats the wet fuel such as brown coal while the wet fuel is made to flow by a fluidizing gas in the flow direction, there is a difference between the water content ratio of the wet fuel at the supply side (the upstream side) in the flow direction) and the water content ratio of the wet fuel at the discharge side (the downstream side) in the flow direction. That is, since the upstream wet fuel in the flow direction is just supplied into the fluid bed drying apparatus, the water content ratio is high. Meanwhile, the downstream wet fuel in the flow direction is heated for a long time inside of the fluid bed drying apparatus compared to the upstream wet fuel in the flow direction, and therefore, the water content ratio decreases. For this reason, since the water content ratio of the wet fuel is high at the upstream side in the flow direction of the fluid bed drying apparatus, the wet fuel may easily aggregate to each other, and may easily adhere to the furnace wall or the furnace bottom. Further, in a case where a heat transfer pipe is provided inside the furnace, the wet fuel easily adheres to the heat transfer pipe. Thus, since the sediments are produced by the adhering of the wet fuel or the aggregates are produced by the aggregation of the wet fuel, there is a concern that the wet fuel may not appropriately flow. SUM-MAY OF THE INVENTION According to a first aspect of the present invention, there is provided a fluid bed drying apparatus including: a drying furnace which forms a fluid bed therein in a manner such that a wet fuel supplied thereto flows in a flow direction by a fluidizing gas; a fuel input port provided in the drying furnace at the upstream side in the flow direction for inputting the wet fuel into the drying 3 furnace; a fuel discharge port provided in the drying furnace at the downstream side in the flow direction for discharging the wet fuel dried inside the drying furnace; and a reverse flow supply portion provided inside the fluid bed for supplying the wet fuel so that the wet fuel is made to reversely flow from the downstream side in the flow direction toward the upstream side therein. According to a second aspect of the present invention, there is provided a gasification combined power generating facility including: the fluid bed drying apparatus according to the first aspect; a gasification furnace for treating the dried wet fuel supplied from the fluid bed drying apparatus so that the fuel is changed into a gasified gas; a gas turbine which is operated by using the gasified gas as fuel; a steam turbine which is operated by steam produced by an exhausted heat recovery boiler into which a turbine flue gas is introduced from the gas turbine; and a generator which is connected to the gas turbine and the steam turbine. According to a third aspect of the present invention, there is provided a drying method of drying a wet fuel while a supplied wet fuel is made to flow in a flow direction by a fluidizing gas, wherein a part of the wet fuel at the downstream side in the flow direction inside the fluid bed is supplied to the upstream side in the flow direction as a reverse flow. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic configuration diagram of a coal gasification combined power generating facility which adopts a fluid bed drying apparatus according to a first embodiment; FIG. 2 is a schematic configuration diagram roughly 4 illustrating the fluid bed drying apparatus according to the first embodiment; FIG. 3 is a schematic configuration diagram roughly illustrating a fluid bed drying apparatus according to a second embodiment; FIG. 4 is a schematic configuration diagram roughly illustrating a fluid bed drying apparatus according to a third embodiment; FIG. 5 is a schematic configuration diagram roughly illustrating a fluid bed drying apparatus according to a fourth embodiment; and FIG. 6 is a plan view roughly illustrating the fluid bed drying apparatus according to the fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a fluid bed drying apparatus and a drying method according to the invention will be described by referring to the accompanying drawings. Incidentally, the invention is not limited to the following embodiments. Further, the components in the following embodiments include components which can be easily replaced by the person skilled in the art or components.which have substantially the same configuration. It is an object of the embodiments to provide a fluid bed drying apparatus, a gasification combined power generating facility, and a drying method capable of causing a wet fuel to appropriately flow. [First embodiment] FIG. 1 is a schematic configuration diagram of a coal gasification combined power generating facility which adopts a fluid bed drying apparatus according to a first embodiment. A coal gasification combined power generating 5 facility (IGCC: Integrated Coal Gasification Combined Cycle) 100 which adopts an air combustion system in which a coal gas is produced in a gasification furnace by using air as an oxidation agent, and supplies the coal gas purified by a gas purification device as a fuel gas to a gas turbine facility so as to generate power. That is, the coal gasification combined power generating facility 100 of the first embodiment is a power generating facility of an air combustion type (air blow). In this case, brown coal is used as wet fuel to be supplied to the gasification furnace. Furthermore, in the first embodiment, brown coal is employed as the wet fuel, but when a high water content is ensured, low-grade coal including sub-bituminous coal or peat such as sludge may be also employed. Further, high grade coal may be also employed. Further, the wet fuel is not limited to coal such as brown coal, and biomass which is used as a renewable biological organic resource may be employed. For example, thinned wood, waste wood, driftwood, grass, waste, mud, a tire, and recycled fuel (pellet or chip) produced therefrom. In the first embodiment, as illustrated in FIG. 1, the coal gasification combined power.generating facility 100 includes a coal supply device 111, a fluid bed drying apparatus 1, a coal pulverizer (mill) 113, a coal gasification furnace 114, a char recovery unit 115, a gas purification device 116, a gas turbine facility 117, a steam.turbine facility 118, a generator 119, and an exhausted heat recovery boiler (HRSG: Heat Recovery Steam Generator) 120. The coal supply device 111 includes a raw coal bunker 121, a coal feeder 122, and a crusher 123. The raw coal bunker 121 can store brown coal, and inputs a predetermined amount of brown coal into the coal feeder 122. The coal 6 feeder 122 conveys the brown coal input from the raw coal bunker 121 by- a conveyor or the like, and inputs the brown coal into the crusher 123. The crusher 123 crushes the input brown coal finely so that the brown coal becomes grains. Although it will be described below, the fluid bed drying apparatus 1 removes the moisture content included in the brown coal by drying the brown coal input from the coal supply device 111 while the brown coal flows by a fluidizing gas such as superheated steam. The fluid bed drying apparatus 1 is connected with a cooler 131 which cools the dry brown coal (the dry coal) discharged therefrom. The cooler 131 is connected with a dry coal bunker 132 which stores the cooled dry coal. Further, the fluid bed drying apparatus 1 is connected with a dry coal cyclone 133 and an electric dry coal dust collector 134 as a dust collecting device 139 which separates dry coal particles from the exhaust gas discharged to the outside. The particles of the dry coal separated from the exhaust gas in the dry coal cyclone 133 and the electric dry coal dust collector 134 are stored in the dry coal bunker 132. Furthermore, the exhaust gas from which the dry coal is separated by the electric dry coal dust collector 134 is compressed by a steam compressor 135 and is used as various heat sources. A coal pulverizer 113 is a coal crusher, and produces pulverized coal by crushing the brown coal (the dry coal) dried by the fluid bed drying apparatus 1 into fine particles. That is, when the dry coal stored in the dry coal bunker 132 is input to the coal pulverizer 113 by a coal feeder 136, the coal pulverizer pulverizes the dry coal into pulverized coal having a predetermined particle diameter or less. Then, the pulverized coal which is 7 pulverized by the coal pulverizer 113 is separated from the carrier gas by pulverized coal bag filters 137a and 137b and is stored in pulverized coal supply hoppers 138a and 138b, To the coal gasification furnace 114, the pulverized coal which is processed by the coal pulverizer 113 is supplied and char (the unburned portion of coal) which is collected by the char recovery unit 115 is supplied. The coal gasification furnace 114 is connected with a compressed air supply line 141 from the gas turbine facility 117 (compressor 161), so that the air compressed by the gas turbine facility 117 may be supplied thereto. An air separating device 142 is used to produce separate nitrogen and oxygen from the air in the atmosphere, a first nitrogen supply line 143 is connected to the coal gasification furnace 114, and the first nitrogen supply line 143 is connected with coal supply lines 144a and 144b from the pulverized coal supply hoppers 138a and 138b. Further, a second nitrogen supply line 145 is also connected to the coal gasification furnace 114, and the second nitrogen supply line 145 is connected with a char return line 146 from the char recovery unit 115. Further, an oxygen supply line 147 is connected to the compressed air supply line 141. In this case, the nitrogen is used as a carrier gas for the coal and the char, and the oxygen is used as an oxidation agent. The coal gasification furnace 114 is, for example, an entrained bed gasification furnace, and is used to burn and gasify the coal, the char, the oxidation agent (the oxygen), or the steam as the gasifying agent supplied thereinto and generates a combustible gas (a product gas and a coal gas) mainly including carbon dioxide, so that a gasification reaction occurs using the combustible gas as a gasifying 8 agent. Furthermore, the coal gasification furnace 114 is provided with a foreign matter removing device 148 which removes foreign matter mixed with the pulverized coal. In this case, the coal gasification furnace 114 is not limited to the entrained bed gasification furnace, and may be also a fluid bed gasification furnace or a fixed bed gasification furnace. Then, in the coal gasification furnace 114, a combustible gas generation line 149 is installed toward the char recovery unit 115, so that the combustible gas including the char may be discharged therethrough. In this case, the gas generation line 149 may be provided with a gas cooler, and the combustible gas may be cooled to a predetermined temperature and be supplied to the char recovery unit 115. The char recovery unit 115 includes a dust collecting device 151 and a supply hopper 152. In this case, the dust collecting device 151 includes one or'plural bag filters or cyclones, and hence may separate the char included in the combustible gas produced by the coal gasification furnace 114. Then, the combustible gas from which the char is separated is sent to the gas purification device 116 through a gas discharge line 153. The supply hopper 152 is used to store the fine char separated from the combustible gas in the dust collecting device 151. Furthermore, a bin may be disposed between the dust collecting device 151 and the supply hopper 152 and a plurality of the supply hoppers 152 may be connected to the bin. Then, the char return line 146 from the supply hopper 152 is connected to the second nitrogen supply line 145. The gas purification device 116 performs gas purification on the combustible gas from which the char is separated by the char recovery unit 115 by removing impurities such as a sulfur compound or a nitrogen compound.

9 Then, the gas purification device 116 produces a fuel gas by purifying the combustible gas and supplies the result to the gas turbine facility 117. Furthermore, in the gas purification device 116, since a sulfur content (1 2 S) is still included in the combustible gas from which the char is separated, the sulfur content is finally collected as gypsum by the removal using amines absorbent and is effectively used. The gas turbine facility 117 includes the compressor 161, a combustor 162, and a turbine 163, and the compressor 161 and the turbine 163 are connected to each other by a rotary shaft 164. The combustor 162 is connected with a compressed air supply line 165 from the compressor 161, and is connected with a fuel gas supply line 166 from the gas purification device 116, so that the turbine 163 is connected with a combustion gas supply line 167. Further, the gas turbine facility 117 is provided with the compressed air supply line 141 which extends from the compressor 161 to the coal gasification furnace 114, and the compressed air supply line 141 is provided with a. booster 168. Accordingly, in the combustor 162, the compressed air supplied from the compressor 161 is mixed with the fuel gas supplied from the gas purification device 116 and is burned. Thus, in the turbine 163, the generator 119 may be driven by rotating the rotary shaft 164 by the produced combustion gas. The steam turbine facility 118 includes a turbine 169 which is connected to the rotary shaft 164 in the gas turbine facility 117, and the generator 119 is connected to the base end of the rotary shaft 164. The exhausted heat recovery boiler 120 is provided in a flue gas line 170 from the gas turbine facility 117 (the turbine 163), and is used to produce steam by the heat exchange between air and the 10 high-temperature flue gas. For this reason, a steam supply line 171 and a steam recovery line 172 are provided between the exhausted heat recovery boiler 120 and the turbine 169 of the steam turbine facility 118, and a condenser 173 is provided in the steam recovery line 172. Accordingly, in the steam turbine facility 118, the turbine 169 is driven by the steam supplied from the exhausted heat recovery boiler 120, and the generator 119 may be driven by the rotation of the rotary shaft 164. Then, the flue gas of which the heat is collected in the exhausted heat recovery boiler 120 passes through a gas purification device 174 so as to remove a toxic material therefrom, and the purified flue gas is discharged from a stack 175 to the atmosphere. Here, an operation of the coal gasification combined power generating facility 100 of the first embodiment will be described. According to the coal gasification combined power generating facility 100 of the first embodiment, in the coal supply device 111, the raw coal (brown coal) is stored in the raw coal bunker 121, and the brown coal of the raw coal bunker 121 is input to the crusher 123 by the coal feeder 122, so that the brown coal is pulverized into a predetermined size. Then, the pulverized brown coal is heated and dried by the fluid bed drying apparatus 1, is cooled by the cooler 131, and is stored in the dry coal bunker 132. Further, the steam which is extracted from the upper portion of the fluid bed drying apparatus 1 passes through the dry coal cyclone 133 and the electric dry coal dust collector 134 so that the particles of the dry coal are separated, and the result is compressed by the steam compressor 135, so that the dry coal is used as various heat sources. Meanwhile, the particles of the dry coal 11 separated from the steam are stored in the dry coal bunker 132. The dry coal which is stored in the dry coal bunker 132 is input to the coal pulverizer 113 by the coal feeder 136. Here, the dry coal is pulverized into fine particles to thereby produce the pulverized coal, and is stored in the pulverized coal supply hoppers 138a and 138b through the pulverized coal bag filters 137a and 137b. The pulverized coal which is stored in the pulverized coal supply hoppers 138a and 138b is supplied to the coal gasification furnace 114 through the first nitrogen supply line 143 by the nitrogen supplied from the air separating device 142. Further, the char which is collected by the char recovery unit 115 to be described later is supplied to the coal gasification furnace 114 through the second nitrogen supply line 145 by the nitrogen supplied from the air separating device 142. Further, the compressed air which is extracted from the gas turbine facility 117 to be described later is boosted by the booster 168, and is supplied to the coal gasification furnace 114 through the compressed air supply line 141 along with the oxygen supplied from the air separating device 142. In the coal gasification furnace 114, the supplied pulverized coal and char are burned by the compressed air (the oxygen), and the pulverized coal and the char are gasified, thereby producing the combustible gas (the coal gas) mainly including carbon dioxide. Then, the combustible gas is discharged from the coal gasification furnace 114 through the gas generation line 149 and is sent to the char recovery unit 115. In the char recovery unit 115, the combustible gas is first supplied to the dust collecting device 151, and the dust collecting device 151 separates the char included in 12 the combustible gas. Then, the combustible gas from which the char is separated is sent to the gas purification device 116 through the gas discharge line 153. Meanwhile, the fine char which is separated from the combustible gas is deposited on the supply hopper 152, and is returned to the coal gasification furnace 114 through the char return line 146 so as to be recovered. The combustible gas from which the char is separated by the char recovery unit 115 passes through the gas purification device 116 so that impurities such as a sulfur compound or a nitrogen compound are removed and the gas is purified, thereby producing a fuel gas. Then, in the gas turbine facility 117, when the compressor 161 produces the compressed air and supplies the compressed air to the combustor 162, the combustor 162 mixes the compressed air supplied from the compressor 161 with the fuel gas supplied from the gas purification device 116 and burns the mixed result to thereby produce a combustion gas. Then, the turbine 163 is driven by the combustion gas, and the generator 119 is driven through the rotary shaft 164, thereby generating power. Then, the flue gas which is discharged from the turbine 163 in the gas turbine facility 117 exchanges heat with air in the exhausted heat recovery boiler 120 so as to produce steam, and the produced steam is supplied to the steam turbine facility 118. In the steam turbine facility 118, the turbine 169 is driven by the steam supplied from the exhausted heat recovery boiler 120, and hence power may be generated by driving the generator 119 through the rotary shaft 164. Subsequently, in the gas purification device 174, the flue gas which is purified by removing the toxic material of the flue gas discharged from the exhausted heat recovery 13 boiler 120 is discharged to the atmosphere from the stack 175. Hereinafter, the fluid bed drying apparatus I of the coal gasification combined power generating facility 100 described above will be described in detail. FIG. 2 is a schematic configuration diagram roughly illustrating the fluid bed drying apparatus according to the first embodiment. The fluid bed drying apparatus 1 of the first embodiment heats and dries brown coal as coal having a high water content while the brown coal flows by a fluidizing gas. As illustrated in FIG. 2, the fluid bed drying apparatus 1 includes a drying furnace 5 into which brown coal is supplied and a gas dispersion plate 6 which is provided inside the drying furnace 5. The drying furnace 5 is formed in a rectangular box shape. The gas dispersion plate 6 divides a space inside the drying furnace 5 into a blowing chamber 11 which is positioned at the lower side (the lower side in the drawing) in the vertical direction and a drying chamber 12 which is positioned at the upper side (the upper side in the drawing) in the vertical direction. The gas dispersion plate 6 is provided with a plurality of penetration holes, and a fluidizing gas such as steam is introduced into the blowing chamber 11. Furthermore, as the gas dispersion plate 6, a plate with a perforation hole or a plate with a nozzle attached to the upper portion of the blowing chamber 11 may be also employed instead of the plate provided with the plurality of penetration holes. The drying chamber 12 of the drying furnace 5 is provided with a brown coal input port (a fuel input port) 31 into which the brown coal is input, a dry coal discharge port (a fuel discharge port) 41 from which the dry coal 14 obtained by heating and drying the brown coal is discharged, a gas discharge port 42 from which the fluidizing gas and the produced steam are discharged as the exhaust gas, and a screw feeder 45. The brown coal input port 31 is formed at the upper side in the vertical direction at one end side (the left side in the drawing) of the drying chamber 12. The brown coal input port 31 is connected with the coal supply device 111, and the brown coal which is supplied from the coal supply device 111 is supplied to the drying chamber 12. The dry coal discharge port 41 is formed at the lower side in the vertical direction on the other end side (the right side in the drawing) of the drying chamber 12. The brown coal which is dried in the drying chamber 12 is discharged as the dry coal from the dry coal discharge port 41, and the discharged dry coal is supplied to the cooler 131. The gas discharge port 42 is formed at the upper side in the vertical direction on the other end side of the drying chamber 12. The gas discharge port 42 discharges the steam produced from the drying chamber 12 along with the fluidizing gas supplied to the drying chamber 12 when drying the brown coal. Furthermore, the fluidizing gas and the produced steam discharged from the gas discharge port 42 are supplied to the dust collecting device 139. Accordingly, the brown coal which is supplied to the drying chamber 12 through the brown coal input port 31 flows by the fluidizing gas supplied through the gas dispersion plate 6, so that a fluid bed 3 is formed inside the drying chamber 12 and the freeboard F is formed above the fluid bed 3. In the fluid bed 3 which is formed in the drying chamber 12, the flow direction thereof becomes a direction from one end side of the drying chamber 12 toward 15 the other end side thereof. The input brown coal is dried while flowing along the flow direction, and the water content included in the brown coal becomes steam. Then, the steam is discharged from the gas discharge port 42 along with the fluidizing gas. The brown coal from which the water content is removed and which flows to the other end side of the drying chamber 12 is discharged as the dry coal from the dry coal discharge port 41. The screw feeder 45 serves as a reverse flow supply portion which supplies a part of the downstream brown coal in the flow direction toward the upstream side in the flow direction as a reverse flow. The screw feeder 45 includes a motor 51 which becomes a driving source, a rotary shaft 52 which is connected to the motor 51, a screw portion 53 which is attached to the rotary shaft 52, and an outer cylinder 54 which covers the screw portion 53. The motor 51 is provided at the outside of the drying furnace 5, and rotates the rotary shaft 52. The rotary shaft 52 is provided so as to penetrate the inside and outside of the drying furnace 5, and rotates the attached screw portion 53. The rotary shaft 52 is provided so as to be horizontal in the flow direction, and is provided at the lower side of the fluid bed 3 in the vertical direction. The screw portion 53 rotates in a manner such that the motor 51 rotates the rotary shaft 52. In the outer cylinder 54, the inner portion becomes a reverse flow supply path 55, and the brown coal flows in the reverse flow supply path 55 from the downstream side toward the upstream side in the flow direction. The outer cylinder 54 stores the rotary shaft 52 and the screw portion 53 therein. Then, the screw feeder 45 is provided at the lower side of the fluid bed 3 in the vertical direction. That is, the screw feeder 45 is provided so as to be adjacent to the 16 gas dispersion plate 6 and is provided so as to be away from the freeboard F. Accordingly, when the rotary shaft 52 is rotated by the motor 51, the screw portion 53 of the screw feeder 45 rotates, so that a part of the brown coal at the lower side of the fluid bed 3 on the downstream side of the drying chamber 12 in the flow direction is received from the downstream end of the outer cylinder 54. The brown coal which is received into the outer cylinder 54 flows from the downstream side in the flow direction of the reverse flow supply path 55 toward the upstream side thereof by the rotation of the screw portion 53. Then, the brown coal which flows in the reverse flow supply path 55 is discharged to the outside from the upstream end of the outer cylinder 54, and is supplied to the drying chamber 12 at the lower side of the fluid bed 3 on the upstream side in the flow direction. In this way, according to the configuration of the first embodiment, a part of the brown coal at the downstream side of the drying chamber 12 may be supplied to the upstream side of the drying chamber 12 by the screw feeder 45. For this reason, the brown coal which has the water content ratio lower than that of the upstream side is supplied to the upstream side of the drying chamber 12. Thus, even when the brown coal is supplied from the brown coal input port 31, the water content ratio of the brown coal at the upstream side of the drying chamber 12 decreases since the brown coal having a low water content ratio is supplied from the downstream side. Accordingly, since the water content ratio of the brown coal decreases, the brown coal may not easily aggregate and adhere to each other. Thus, since the generation of the sediment caused by the adhering of the brown coal is suppressed and the 17 generation of the aggregates caused by the aggregating of the brown coal may be suppressed, the brown coal may be appropriately moved in a flowing state. Further, according to the configuration of the first embodiment, since the screw feeder 45 is provided inside of the fluid bed 3 and the brown coal may be supplied by the screw feeder 45 from the downstream side in the flow direction toward the upstream side thereof, it is possible to simplify the fluid bed drying apparatus 1 without complicating the configuration. Further, according to the configuration of the first embodiment, since the screw feeder 45 is provided at the lower side of the fluid bed 3, the brown coal at the lower side of the fluid bed 3 may be supplied from the downstream side of the drying chamber 12 to the upstream side thereof. That is, the brown coal around the dry coal discharge port 41 may be supplied to the lower side of the fluid bed 3 at the upstream side of the drying chamber 12. For this reason, since the fluid bed drying apparatus 1 may supply the downstream brown coal toward the upstream brown coal of the drying chamber 12 which may be easily deposited at the lower side of the fluid bed 3, the generation of the flowing problem may be appropriately suppressed. [Second embodiment] Next,. a fluid bed drying apparatus 200 according to a second embodiment will be described by referring to FIG. 3. FIG. 3 is a schematic configuration diagram roughly illustrating the fluid bed-drying apparatus according to the second embodiment. Furthermore, in the second embodiment, the difference from the first embodiment is described so as to prevent the repetitive description, and the same component as that of the first embodiment is 18 denoted by the same letter or numeral. In the fluid bed drying apparatus 1 according to the first embodiment, the screw feeder 45 is provided at the lower side of the fluid bed 3 in the vertical direction. However, in a fluid bed drying apparatus 200 according to the second embodiment, a screw feeder 201 is provided at the upper side of the fluid bed 3 in the vertical direction. Hereinafter, the fluid bed drying apparatus 200 according to the second embodiment will be described. As illustrated in FIG. 3, in the fluid bed drying apparatus 200 according to the second embodiment, the screw feeder 201 has the same configuration as that of the first embodiment and serves as a reverse flow supply portion which supplies a part of the downstream brown coal in the flow direction as a reverse flow to the upstream side in the flow direction. That is, as in the first embodiment, the screw feeder 201 includes the motor 51, the rotary shaft 52, the screw portion 53, and the outer cylinder 54. Then, in the screw feeder 201, the rotary shaft 52 is horizontally provided in the flow direction, and is provided at the upper side of the fluid bed 3 in the vertical direction. That is, the screw feeder 201 is provided at the upper side in the vertical direction away from the gas dispersion plate 6 and is provided near the freeboard F. Accordingly, when the rotary shaft 52 is rotated by the motor 51, the screw portion 53 of the screw feeder 201 rotates, so that a part of the brown coal at the upper side of the fluid bed 3 on the downstream side of the drying chamber 12 in the flow direction is received from the downstream end of the outer cylinder 54. The brown coal which is received into the outer cylinder 54 flows from the downstream side in -the flow direction of the reverse flow 19 supply path 55 toward the upstream side thereof by the rotation of the screw portion 53. Then, the brown coal which flows in the reverse flow supply path 55 is discharged to the outside from the upstream end of the outer cylinder 54, and is supplied to the drying chamber 12 at the upper side of the fluid bed 3 on the upstream side in the flow direction. In this way, according to the configuration of the second embodiment, since the screw feeder 201 is provided at the upper side of the fluid bed 3, the brown coal at the upper side of the fluid bed 3 may be supplied from the downstream side of the drying chamber 12 to the upstream side thereof. For this reason, since the fluid bed drying apparatus 200 does not disturb the flow of the brown coal at the lower side of the fluid bed by the screw feeder 201, a part of the downstream brown coal may be appropriately supplied to the upstream side while the brown coal is made to appropriately flow in the flow direction. [Third embodiment] Next, a fluid bed drying apparatus 210 according to a third embodiment will be described by referring to FIG. 4. FIG. 4 is a schematic configuration diagram roughly illustrating the fluid bed drying apparatus according to the third embodiment. Furthermore, even in the third embodiment, the difference from the first embodiment is described so as to prevent the repetitive description, and the same component as that of the first embodiment is denoted by the same letter or numeral. In the fluid bed drying apparatus 1 according to the first embodiment, the screw feeder 45 is provided at the lower side of the fluid bed 3 in the vertical direction. However, in the fluid bed drying apparatus 210 according to the third embodiment, a 20 screw feeder 211 is provided so as to be inclined in the flow direction. Hereinafter, the fluid bed drying apparatus 210 according to the third embodiment will be described. As illustrated in FIG. 4, in the fluid bed drying apparatus 210 according to the third embodiment, the screw feeder 211 has the same configuration as that of the first embodiment and serves as a reverse flow supply portion which supplies a part of the downstream brown coal in the flow direction as a reverse flow to the upstream side in the flow direction. That is, as in the first embodiment, the screw feeder 211 includes the motor 51, the rotary shaft 52, the screw portion 53, and the outer cylinder 54. Then, in the screw feeder 211, the rotary shaft 52 is provided throughout the flow direction, and the rotary shaft 52 is provided so as to be inclined in the horizontal direction. That is, the rotary shaft 52 is provided, so that the upstream end in the flow direction is provided at the upper side of the fluid bed in the vertical direction and the downstream end in the flow direction is provided at the lower side of the fluid bed in the vertical direction. For this reason, in the screw feeder 211, the upstream end in the flow direction is positioned around the brown coal input port 31 and the downstream end in the flow direction is positioned around the dry coal discharge port 41. Accordingly, when the -rotary shaft 52 is rotated by the motor 51, the screw portion 53 of the screw feeder 211 rotates, so that a part of the brown coal at the lower side of the fluid bed 3 on the downstream side of the drying chamber 12 in the flow direction is received from the downstream end of the outer cylinder 54. The brown coal which is received into the outer cylinder 54 flows from the downstream side in the flow direction of the reverse flow 21 supply path 55 toward the upstream side thereof by the rotation of the screw portion 53. Then, the brown coal which flows in the reverse flow supply path 55 is discharged to the outside from the upstream end of the outer cylinder 54, and is supplied to the drying chamber 12 at the upper side of the fluid bed 3 on the upstream side in the flow direction. In this way, according to the configuration of the third embodiment, since the upstream end of the screw feeder 211 is provided at the upper side of the fluid bed 3 and the downstream end of the screw feeder 211 is provided at the lower side of the fluid bed 3, the brown coal at the lower side of the fluid bed 3 on the downstream side of the drying chamber 12 may be supplied to the upper side of the fluid bed 3 on the upstream side of the drying chamber 12. That is, the brown coal around the dry coal discharge port 41 may be supplied to the periphery of the brown coal input port 31. For this reason, since the fluid bed drying apparatus 210 may supply the brown coal having a low water content ratio near the dry coal discharge port 41 toward the brown coal having a high water content ratio immediately after the input of the brown coal, it is possible to appropriately decrease the water content ratio of the brown coal at the upstream side in the flow direction. [Fourth embodiment] Next, a fluid bed drying apparatus 220 according to a fourth embodiment will be described by referring to FIGS. 5 and 6. FIG. 5 is a schematic configuration diagram roughly illustrating the fluid bed drying apparatus according to the fourth embodiment. FIG. 6 is a top view roughly illustrating the fluid bed drying apparatus according to 22 the fourth embodiment. Furthermore, even in the fourth embodiment, the difference from the first embodiment is described so as to prevent the repetitive description, and the same component as that of the first embodiment is denoted by the same letter or numeral. In the fluid bed drying apparatus 1 according to the first embodiment, one drying chamber 12 is provided with one screw feeder 45. However, in the fluid bed drying apparatus 220 according to the fourth embodiment, the drying chamber 12 is divided into a plurality of chambers in the flow direction by a dividing plate 222, and a plurality of screw feeders 221 are provided. Hereinafter, the fluid bed drying apparatus 220 according to the fourth embodiment will be described. As illustrated in FIG. 5, the fluid bed drying apparatus 220 according.to the fourth embodiment includes the drying furnace 5 which has the blowing chamber 11 provided at the lower side and the drying chamber 12 provided at the upper side with the gas dispersion plate 6 interposed therebetween. A plurality of dividing plates 222 are provided inside the drying furnace 5. The plurality of dividing plates 222 divides the drying chamber 12 into a plurality of chambers in the flow direction of the brown coal. In the fourth embodiment, two dividing plates 222 are provided, and three drying chambers 12 are provided. That is, an upstream drying chamber 12a in the flow direction, a middle drying chamber 12b in the flow direction, and a downstream drying chamber 12c in the flow direction are divided from each other. As in the first embodiment, the drying chamber 12 of the drying furnace 5 is provided with the brown coal input port 31 through which the brown coal is input, the dry coal discharge port 41 through which the dry coal obtained by heating and drying the brown coal is discharged, the gas 23 discharge port 42 through which the fluidizing gas and the produced steam are discharged, and the plurality of screw feeders 221. The brown coal input port 31 is provided at the upper side in the vertical direction on one end side (the left side in the drawing) of the upstream drying chamber 12a. The brown coal input port 31 is connected with the coal supply device 111, and the brown coal which is supplied from the coal supply device 111 is supplied to the upstream drying chamber 12a. The dry coal discharge port 41 is provided at the lower side in the vertical direction on the other end side (the right side in the drawing) of the downstream drying chamber 12c. The brown coal which is dried in the drying chamber 12 is discharged as the dry coal from the dry coal discharge port 41, and the discharged dry coal is supplied toward the cooler 131 described above. The gas discharge port 42 is provided at the upper side in the vertical direction on the other end side of the downstream drying chamber 12c. Through the gas discharge port 42, the steam produced from the drying chamber 12 is discharged along with the fluidizing gas supplied to the drying chamber 12 when drying the brown coal. Furthermore, the fluidizing gas and the produced steam which are discharged from the gas discharge port 42 are supplied toward the dust collecting device 139. Accordingly, the brown coal which is supplied to the upstream drying chamber 12a through the brown coal input port 31 flows by the fluidizing gas supplied through the gas dispersion plate 6, so that the fluid bed 3 is formed from the upstream drying chamber 12a to the downstream drying chamber 12c and the freeboard F is formed above the fluid bed 3. In the fluid bed 3 formed in the drying 24 chamber 12, the flow direction becomes a direction from one end side of the drying chamber 12 toward the other end side thereof. Then, the brown coal which is supplied to the upstream drying chamber 12a is dried while flowing in the flow direction, so that the water content included in the brown coal becomes the produced steam and is discharged from the gas discharge port 42 along with the fluidizing gas. The brown coal from which the water content is removed and which flows to the other end side of the downstream drying chamber 1 2 c is discharged as the dry coal from the dry coal discharge port 41. In the fourth embodiment, two screw feeders are provided as the plurality of screw feeders 221, where one screw feeder 221a is provided between the upstream drying chamber 12a and the downstream drying chamber 12c, and the other screw feeder 221b is provided between the middle drying chamber 12b and the downstreaia drying chamber 12c. Further, as illustrated in FIG. 6, two screw feeders 221a and 221b are provided in parallel at a predetermined gap in the width direction perpendicular to the flow direction. One screw feeder 2 21a has the same configuration as that of the first embodiment, and a part of the brown coal of the downstream drying chamber 12c is supplied to the upstream drying chamber 12a as a reverse flow. That is, as in the first embodiment, the screw feeder 221a includes a motor 51a, a rotary shaft 52a, a screw portion 53a, and an outer cylinder 54a. Then, in the screw feeder 221a, the outer cylinder 54a is provided so as to penetrate two dividing plates 222, and the rotary shaft 52a is horizontally provided in the flow direction and is provided at the lower side of the fluid bed 3 in the vertical direction. The other screw feeder 221b also has the same 25 configuration as that of the first embodiment, and supplies a part of the brown coal of the downstream drying chamber 12c to the middle drying chamber 12b as a reverse flow. That is, as in the first embodiment, the screw feeder 221b includes a motor 51b, a rotary shaft 52b, a screw portion 53b, and an outer cylinder 54b. Then, in the screw feeder 221b, the outer cylinder 54b is provided so as to penetrate one dividing plate 222, and the rotary shaft 52b is provided horizontally in the flow direction and is provided at the lower side of the fluid bed 3 in the vertical direction. Accordingly, when the rotary shaft 52a is rotated by the motor 51a, the screw portion 53a of one screw feeder 221a rotates, so that a part Qf the brown coal at the lower side of the fluid bed 3 in the downstream drying chamber 12c is received'from the downstream end of the outer cylinder 54a. The brown coal which is received into the outer cylinder 54a flows from the downstream side of a reverse flow supply path 55a in the flow direction toward the upstream side by the rotation of the screw portion 53a. Then, the brown coal which flows in the reverse flow supply path 55a is discharged from the upstream end of the outer cylinder 54a to the outside, and is supplied to the upstream drying chamber 12a at the lower side of the fluid bed 3. Further, when the rotary shaft 52b is rotated by the motor 51b, the screw portion 53b of the other screw feeder 221b rotates, so that a part of the brown coal at the lower side of the fluid bed 3 in the downstream drying chamber 12c is received from the downstream end of the outer cylinder 54b. The brown coal which is received into the outer cylinder 54b flows from the downstream side of a reverse flow supply path 55b in the flow direction toward 26 the upstream side by the rotation of the screw portion 53b. Then, the brown coal which flows in the reverse flow supply path 55b is discharged from the upstream end of the outer cylinder 54b to the outside, and is supplied to the middle drying chamber 12b at the lower side of the fluid bed 3. In this way, according to the configuration of the fourth embodiment, a part of the brown coal in the downstream drying chamber 12c may be supplied to the upstream drying chamber 12a by one screw feeder 221a. Further, a part of the brown coal in the downstream drying chamber 12c may be supplied to the middle drying chamber 12b by the other screw feeder 221b. For this reason, the brown coal of the downstream drying chamber 12c having a low water content ratio is supplied to the upstream drying chamber 1 2a. Further, the brown coal of the downstream drying chamber 12c having a low water content ratio is supplied to the middle drying chamber 12b. Thus, even when the brown coal is supplied from the brown coal input port 31 to the upstream drying chamber 12a, the water content ratio decreases since the brown coal having a low water content ratio is supplied from the downstream drying chamber 12c. Further, since the brown coal having a low water content ratio is supplied from the downstream drying chamber 12c to the middle drying chamber 12b, the water content ratio decreases. Accordingly, since the water content ratio of the brown coal decreases, the brown coal may not easily aggregate and adhere to each other. Thus, since it is possible to suppress the generation of the sediments caused by the adhering of the brown coal and to suppress the generation of the aggregates caused by the aggregating of the brown coal, it is possible to cause the brown coal to appropriately flow. Furthermore, in the first to fourth embodiments, the 27 brown coal is supplied from the downstream side in the flow direction toward the upstream side therein by using the screw feeders 45, 201, 211, and 221, but the configuration is not limited. For example, a scraper chain conveyor may be employed instead of the screw feeders 45, 201, 211, and 221. In this case, it is desirable to provide the scraper chain conveyor inside the drying chamber 12. Further, in the fourth embodiment, the drying chamber 12 is divided into the plurality of chambers in the flow direction by the dividing plates 222, and the plurality of screw feeders 221 are provided. However, even when the drying chamber 12 is not divided into the plurality of drying chambers, it is possible to obtain the same effect by providing the plurality of screw feeders 221. According to the configurations of these embodiments, a part of the wet fuel at the downstream side in the flow direction may be supplied to the upstream side in the flow direction by the reverse flow supply portion. For this reason, the wet fuel having a water content ratio lower than that of the upstream side in the flow direction is supplied into the drying furnace at the upstream side in the flow direction. Thus, even when the wet fuel is supplied from the fuel input port, the water content ratio of the wet fuel which flows inside the drying furnace at the upstream side in the flow direction decreases because the wet fuel having a low water content ratio is supplied from the downstream side in the flow direction. Accordingly, since the water content ratio of the wet fuel decreases, the wet fuel may not easily aggregate and adhere to each other. Thus, since the generation of the sediments caused by the adhering of the wet fuel can be prevented and the generation of the aggregates caused by the aggregating of the wet fuel can be prevented, the wet fuel can be 28 appropriately moved in a flowing state. In this case, it is preferable that the inside of. the drying-furnace be divided by the plurality of drying chambers in the flow direction and the reverse flow supply portion supply the wet fuel as a reverse flow from the downstream drying chamber in the flow direction toward the upstream drying chamber in the flow direction. According to the configurations of these embodiments, a part of the wet fuel of the downstream drying chamber can be supplied to the upstream drying chamber by the reverse flow supply portion. For this reason, the wet fuel having a low water content ratio compared to that of the upstream drying chamber is supplied into the upstream drying chamber Thus, even when the wet fuel is supplied from the fuel input port, the water content ratio of the wet fuel which flows in the upstream drying chamber decreases because the wet fuel having a low water content ratio is supplied from the downstream drying chamber. Accordingly, since the water content ratio of the wet fuel decreases, the wet fuel may not easily aggregate and adhere to each other. Thus, since it is possible to suppress the generation of the sediments caused by the adhering of the wet fuel in the upstream drying chamber and to suppress the generation of the aggregates caused by the aggregating of the wet fuel, the wet fuel can appropriately flow. In this case, it is preferable that the plurality of drying chambers be three drying chambers which include an upstream drying chamber in the flow direction, a middle drying chamber in the flow direction, and a downstream drying chamber in the flow direction, and the reverse flow supply portion supply the wet fuel while the wet fuel is made to reversely flow from the downstream drying chamber in the flow direction toward the middle drying chamber in 29 the flow direction and supply the wet fuel while the wet fuel is made to reversely flow from the downstream drying chamber in the flow direction toward the upstream drying chamber in the flow direction. According to the configurations of these embodiments, a part of the wet fuel of the downstream drying chamber can be supplied to each of the middle drying chamber and the upstream drying chamber by the reverse flow supply portion. Thus, since it is possible to decrease the water content ratio of the wet fuel in each of the middle drying chamber and the upstream drying chamber, it becomes difficult that the wet fuel aggregates and adheres to each other. Accordingly, since it is possible to suppress the generation of the sediments caused by the adhering of the wet fuel in the middle drying chamber and the upstream drying chamber and to suppress the generation of the aggregates caused by the aggregating of the wet fuel, the wet fuel can appropriately flow. According to the configurations of these embodiments, since the screw feeder is provided inside of the fluid bed, it is possible to supply the wet fuel from the downstream side in the flow direction toward the upstream side therein with a simple configuration. According to the configurations of these embodiments, the screw feeder can supply the wet fuel at the lower side of the fluid bed from the downstream side toward the upstream side. For this reason, since the downstream wet fuel can be supplied toward the upstream wet fuel which is easily deposited at the lower side of the fluid bed, the generation of the flowing problem can be appropriately suppressed. In this case, it is preferable that the screw feeder be provided throughout the flow direction and be provided 30 at the upper side of the fluid bed in the vertical direction. According to the configurations of these embodiments, since the flow of the wet fuel at the lower side of the fluid bed is not disturbed by the screw feeder, the downstream wet fuel can be supplied toward the upstream side while the wet fuel is made to appropriately flow in the flow direction. According to the configurations of these embodiments, the screw feeder can supply the wet fuel around the fuel discharge port toward the fuel input port. For this reason, since the screw feeder can supply the wet fuel having a low water content ratio near the fuel discharge port toward the wet fuel having a high water content ratio immediately after the input of the fuel, the water content ratio of the wet fuel at the upstream side in the flow direction can be appropriately decreased. According to the configurations of these embodiments, the wet fuel which appropriately flow and is dried in the fluid bed drying apparatus can be supplied to the gasification furnace. According to the configurations of these embodiments, a part of the wet fuel at the downstream side in the flow direction can be supplied to the upstream side in the flow direction. For this reason, the wet fuel having a low water content ratio compared to that of the upstream side in the flow direction is supplied to the wet fuel at the upstream side in the flow direction. Thus, since the wet fuel having a low water content ratio is supplied from the downstream side in the flow direction into the wet fuel at the upstream side in the flow direction, the water content ratio decreases. Accordingly, since the water content ratio of the wet fuel decreases, it becomes difficult that 31 the wet fuel aggregate and adhere to each other. Thus, since it is possible to suppress the generation of the sediments caused by the adhering of the wet fuel and to suppress the generation of the aggregates caused by the aggregating of the wet fuel, the wet fuel can appropriately flow. According to the fluid bed drying apparatus and the drying method of the these embodiments, since it is possible to decrease the water content ratio of the wet fuel at the upstream side in the flow direction, it is possible to suppress the sedimentation and the aggregation of the wet fuel and thus to cause the wet fuel to appropriately flow.

Claims (12)

1. A fluid bed drying apparatus comprising: a drying furnace which forms a fluid bed therein in a manner such that a wet fuel supplied thereto flows in a flow direction by a fluidizing gas; a fuel input port provided in the drying furnace at the upstream side in the flow direction for inputting the wet fuel into the drying furnace; a fuel discharge port provided in the drying furnace at the downstream side in the flow direction for discharging the wet fuel dried inside the drying furnace; and a reverse flow supply portion provided inside the fluid bed -for supplying the wet fuel so that the wet fuel is made to reversely flow from the downstream side in the flow direction toward the upstream side therein.

2. The fluid bed drying apparatus according to claim 1, wherein the inside of the drying furnace is divided by a plurality of drying chambers in the flow direction, and the reverse flow supply portion is configured to supply the wet fuel while the wet fuel is made to reversely flow from the drying chamber at the downstream side in the flow direction toward the drying chamber at the upstream side in the flow direction.

3. The fluid bed drying apparatus according to claim 2, wherein the plurality of drying chambers are three drying chambers which include an upstream drying chamber in the flow direction, a middle drying chamber in the flow direction, and a downstream drying chamber in the flow direction, and 33 the reverse flow supply portion is configured to supply the -wet fuel while the wet fuel is made to reversely flow from the downstream drying chamber in the flow direction toward the middle drying chamber in the flow direction and supply the wet fuel while the wet fuel is made to reversely flow from the downstream drying chamber in the flow direction toward the upstream drying chamber in the flow direction.

4. The fluid bed drying apparatus according to any one of claims 1 to 3, wherein the reverse flow supply portion includes a screw feeder for supplying the wet fuel from the downstream side toward the upstream side in the flow direction.

5. The fluid bed drying apparatus according to claim 4, wherein the screw feeder is provided throughout the flow direction, and is provided at the lower side of the fluid bed in the vertical direction.

6. The fluid bed drying apparatus according to claim 4, wherein the screw feeder is provided throughout the flow direction, and is provided at the upper side of the fluid bed in the vertical direction.

7. The fluid bed drying apparatus according to claim 4, wherein the fuel input port is provided at the upper side of the drying furnace in the vertical direction, the fuel discharge port is provided at the lower side of the drying furnace in the vertical direction, and the screw feeder is provided so as to be inclined in the flow direction so that an upstream end in the flow direction is provided at the upper side of the fluid bed in - 34 the vertical direction and a downstream end in the flow direction is provided at the lower side of the fluid bed in the vertical direction.

8. A gasification combined power generating facility comprising: the fluid bed drying apparatus according to any one of claims 1 to 7; a gasification furnace for treating the dried wet fuel supplied from the fluid bed drying apparatus so that the fuel is changed into a gasified gas; a gas turbine which is operated by using the gasified gas as fuel; a steam turbine which is operated by steam produced by an exhausted heat recovery boiler into which a turbine flue gas is introduced from the gas turbine; and a generator which is connected to the gas turbine and the steam turbine.

9. A drying method of drying a wet fuel while a supplied wet fuel is made to flow in a flow direction by a fluidizing gas, wherein a part of the wet fuel at the downstream side in the flow direction inside the fluid bed is supplied to the upstream side in the flow direction as a reverse flow.

10. A fluid bed drying apparatus substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying examples and/or drawings.

11. A gasification combined power generating facility substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying examples and/or drawings.

12. A drying method for drying a wet fuel substantially as herein described with reference to any one of the embodiments of the invention illustrated in the accompanying examples and/or drawings.