AU2013201106B2

AU2013201106B2 - Fluid bed drying apparatus, gasification combined power generating facility, and drying method

Info

Publication number: AU2013201106B2
Application number: AU2013201106A
Authority: AU
Inventors: Koji Ohura
Original assignee: Mitsubishi Heavy Industries Ltd
Current assignee: Mitsubishi Heavy Industries Ltd
Priority date: 2012-02-28
Filing date: 2013-02-26
Publication date: 2014-08-28
Anticipated expiration: 2033-02-26
Also published as: JP5812896B2; JP2013178028A; AU2013201106A1

Abstract

Provided are a fluid bed drying apparatus including: a drying furnace into which a wet fuel is supplied; a fluidizing steam supply unit for supplying fluidizing steam to the drying furnace and fluidizes the wet fuel so as to form a fluid bed inside the drying furnace; a heat transfer member provided inside the drying furnace for heating the supplied wet fuel; and a compressor for compressing the steam discharged from the drying furnace and supplying the compressed steam toward the heat transfer member, wherein the drying furnace includes: an upstream drying chamber and a downstream drying chamber, wherein the heat transfer member includes: an upstream heat transfer member and a downstream heat transfer member, so that the steam supplied from the compressor circulates in the downstream heat transfer member and then circulates in the upstream heat transfer member, wherein the compressor is configured to compress the steam discharged from the downstream drying chamber, and wherein the fluidizing steam supply unit is configured to supply the fluidizing steam to the upstream drying chamber and the downstream drying chamber, and supply the fluidizing steam of which a content ratio of a non-condensable gas is larger than that of the downstream drying chamber to the upstream drying chamber. CDt 'D LO (D L) I0 Z<)I U.' m c 'o 1CM LO LIn -CJ r_

Description

1 FLUID BED DRYING APPARATUS, GASIFICATION COMBINED POWER GENERATING FACILITY, AND DRYING METHOD 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 Hitherto, there are known a method and an apparatus for drying low-grade coal in a manner such that low-grade coal such as brown coal is supplied from a hopper toward a drying container and the low-grade coal supplied into the drying container is dried while being fluidized by steam (moisture vapor) (for example, see Japanese Laid-open Patent Publication No. 61-250096). In the low-grade coal drying apparatus, latent heat of steam is collected by supplying steam discharged from a drying container to a condenser. Incidentally, in a fluid bed drying apparatus which dries a wet fuel such as brown coal while fluidizing the wet fuel by fluidizing steam (moisture vapor), there is a case in which the steam discharged from the fluid bed drying apparatus is recompressed for use. Here, in the fluid bed drying apparatus, it is difficult to eliminate the possibility of the mixing of a non-condensable gas such as air including nitrogen. For this reason, the recompressed steam is mixed with the non-condensable gas. The recompressed steam is used to heat, for example, the wet fuel, and exchanges heat with respect to the wet fuel. In this case, since the recompressed steam exchanges heat with respect to the wet fuel, the quality of the steam 2 decreases. When the quality of the steam decreases, since the ratio of the liquid-phase steam (that is, condensed water) with respect to the entire amount of the steam increases, the ratio of the non-condensable gas included in 5 the gas-phase component in the low-quality steam increases. Accordingly, since the ratio of the non-condensable gas included in the gas-phase component in the low-quality steam increases, the temperature of the steam decreases. For this reason, when heating the wet fuel by the low 10 quality steam of which the temperature of the steam decreases, it is difficult to appropriately ensure the temperature difference between the temperature of the steam and the temperature of the wet fuel. Any discussion of the prior art throughout the 15 specification should in no way be considered as an admission that such prior art is widely known or forms part of common general knowledge in the field. Unless the context clearly requires otherwise, throughout the description and the claims, the words 20 "comprise", "comprising", and the like are to be construed in an inclusive sense as opposed to an exclusive or exhaustive sense; that is to say, in the sense of "including, but not limited to". SUMMARY OF THE INVENTION 25 According to a first aspect of the present invention, there is provided a fluid bed drying apparatus including: a drying furnace into which a wet fuel is supplied; a fluidizing steam supply unit for supplying fluidizing steam to the drying furnace and fluidizes the wet fuel so as to 30 form a fluid bed inside the drying furnace; a heat transfer member provided inside the drying furnace for heating the supplied wet fuel; and a compressor for compressing the steam discharged from the drying furnace and supplying the 2a compressed steam toward the heat transfer member, wherein the drying furnace includes: an upstream drying chamber provided at the upstream side of the flow direction of the wet fuel and a downstream drying chamber provided at the 5 downstream side of the upstream drying chamber, wherein the heat transfer member includes: an upstream heat transfer member provided in the upstream drying chamber and a downstream heat transfer member provided in the downstream drying chamber, so that the steam supplied from the 3 compressor circulates in the downstream heat transfer member and then circulates in the upstream heat transfer member, wherein the compressor is configured to compress the steam discharged from the downstream drying chamber, and wherein the fluidizing steam supply unit is configured to supply the fluidizing steam to the upstream drying chamber and the downstream drying chamber, and supply the fluidizing steam of which a content ratio of a non condensable gas is larger than that of the downstream drying chamber to the upstream drying chamber. 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 gasifying furnace for treating the dried wet fuel supplied from the fluid bed drying apparatus so that the wet fuel is changed into a gasifying gas; a gas turbine operated by using the gasifying gas as a fuel; a steam turbine 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 by heating the wet fuel using a heat transfer member provided inside a drying furnace while circulating the wet fuel supplied into the drying furnace using fluidizing steam, wherein the drying furnace includes: an upstream drying chamber provided at the upstream side of the flow direction of the wet fuel and a downstream drying chamber provided at the downstream side of the upstream drying chamber, wherein the heat transfer member includes: an upstream heat transfer member provided in the upstream drying chamber and 4 a downstream heat transfer member provided in the downstream drying chamber, and wherein the drying method comprises: supplying the fluidizing steam to the upstream drying chamber and the downstream drying chamber; supplying the fluidizing steam of which a content ratio of a non condensable gas is larger than that of the downstream drying chamber as a fluidizing gas to the upstream drying chamber; discharging steam produced when drying the wet fuel from the downstream drying chamber; compressing the steam discharged in the discharging of steam; supplying the steam compressed in the compressing of steam to the downstream heat transfer member; and supplying the steam circulating in the downstream heat transfer member to the upstream heat transfer member. 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 illustrating the fluid bed drying apparatus according to the first embodiment; FIG. 3 is a graph illustrating a quality of recompressed steam in the fluid bed drying apparatus according to the first embodiment; FIG. 4 is a graph illustrating an example of the quality of the recompressed steam in the fluid bed drying apparatus according to the first embodiment; FIG. 5 is a schematic configuration diagram roughly illustrating a fluid bed drying apparatus according to a second embodiment; FIG. 6 is a schematic configuration diagram roughly 5 illustrating a fluid bed drying apparatus according to a first modified example; FIG. 7 is a schematic configuration diagram roughly illustrating a fluid bed drying apparatus according to a second modified example; FIG. 8 is a schematic configuration diagram roughly illustrating a fluid bed drying apparatus according to a third modified example; FIG. 9 is a schematic configuration diagram roughly illustrating a fluid bed drying apparatus according to a fourth modified example; FIG. 10 is a schematic coAfiguration diagram roughly illustrating a fluid bed drying apparatus according to a fifth modified example; and FIG. 11 is' a schematic configuration diagram roughly illustrating a fluid bed drying apparatus according to a sixth modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a fluid bed drying apparatus, a gasification combined power generating facility, and a drying method according to the invention will be described by referring to the accompanying drawings. Furthermore, the invention is not limited to the following embodiments. Further, the components in the following embodiments include a component which may be easily replaced by the person skilled in the art or a component which has substantially the same configuration. It is an object of the embodiments of the present invention to provide a fluid bed drying apparatus and a drying method capable of improving the efficiency of collecting latent heat of steam by appropriately drying a wet fuel using low-quality steam.

6 [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 facility (IGCC: Integrated Coal Gasification Combined Cycle) 100 which adopts a fluid bed drying apparatus 1 of the first embodiment adopts an air combustion type 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 (air blow) type. In this case, brown coal is used as a 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 subbituminous 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 may be employed. In the first embodiment, as illustrated in FIG. 1, the coal gasification combined power generating facility 100 includes a coal supply device 111, the fluid bed drying apparatus 1, a coal pulverizer 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 may store brown coal, and inputs a predetermined amount of brown coal into the coal feeder 122. The coal 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 later in detail, the fluid bed drying apparatus 1 removes a water content included in the brown coal in a manner such that the brown coal input from the coal supply device 111 is fluidized by a fluidizing gas such as moisture vapor and is heated and dried by heat transfer tubes 33 and 43. 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 supplied as a heat medium to the heat transfer tubes 33 and 43 of the 8 fluid bed drying apparatus 1. The 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 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 (a 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 9 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 moisture vapor 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 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 10 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. 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 (H 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 11 119 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 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 12 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 exhaust gas which is discharged from 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. Then, the result is compressed by the steam compressor 135 and is returned as a heat medium to the heat transfer tubes 33 and 43 of the fluid bed drying apparatus 1. Meanwhile, the particles of the dry coal 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 13Bb 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 13 (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 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 recycled. 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 14 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 boiler 120 is discharged to the atmosphere from the stack 175. Hereinafter, the fluid bed drying apparatus 1 of the coal gasification combined power generating facility 100 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 is used to heat and dry the brown coal input by the coal supply device 111 while fluidizing the brown coal by the fluidizing gas. As illustrated in FIG. 2, the fluid bed drying apparatus 1 includes a drying furnace 5 into which the brown coal is supplied. The drying furnace 5 includes an upstream drying furnace 5a and a downstream drying furnace 5b. The upstream drying furnace 5a has an upstream gas dispersion plate 6a provided therein and the downstream drying furnace 5b has a downstream gas dispersion plate Gb provided therein. The upstream drying furnace 5a and the downstream drying furnace 5b are formed in a rectangular box shape. The upstream gas dispersion plate 6a divides a space inside the upstream drying furnace 5a into an upstream wind chamber 11a which is positioned at the lower side (the lower side in the drawing) in the vertical 15 direction and an upstream drying chamber 12a which is positioned at the upper side (the upper side in the drawing) in the vertical direction. Similarly, the downstream gas dispersion plate 6b divides a space inside the downstream drying furnace 5b into a downstream wind chamber 1lb which is positioned at the lower side (the lower side of the drawing) in the vertical direction and a downstream.drying chamber 12b which is positioned at the upper side (the upper side in the drawing) in the vertical direction. The upstream gas dispersion plate 6a and the downstream gas dispersion plate 6b are provided with a plurality of penetration holes. The fluid bed drying apparatus 1 includes a fluidizing steam supply unit 21 which supplies the fluidizing steam to the upstream wind chamber 1la and the downstream wind chamber 1lb and a gas supply unit 25 which supplies a non condensable gas such as nitrogen to the upstream wind chamber 11a. The fluidizing steam supply unit 21 is connected to the upstream wind chamber 1la and the downstream wind chamber lb and supplies the fluidizing steam thereto. Meanwhile, the gas supply unit 25 is connected to a supply line which connects the fluidizing steam supply unit 21 and the upstream wind chamber ala to each other, and supplies the non-condensable gas as the fluidizing gas along with the fluidizing steam. For this reason, since the fluidizing gas is introduced into the upstream drying chamber 12a through the upstream wind chamber Ila, the dew-point temperature inside the upstream drying chamber 12a may become lower than 100 0 C. Meanwhile, since the fluidizing steam is introduced into the downstream drying chamber 12b through the downstream wind chamber 11b, the dew-point temperature inside the downstream drying chamber 12b needs to be about 100"C.

16 Furthermore, as the non-condensable gas supplied from the gas supply unit 25, for example, a gas may be supplied from an external non-condensable gas supply device, and a flue gas discharged from a gas turbine or a boiler may be supplied. The upstream drying chamber 12a of the upstream drying furnace 5a is provided with an upstream brown coal input port 31 through which the brown coal is input, an upstream dry coal discharge port 34 through which the dry coal obtained by heating and drying the brown coal is discharged, a gas discharge port 35 through which the fluidizing gas and the steam produced in the drying process are discharged, and an upstream heat transfer tube (the upstream heat transfer member) 33 which heats the brown coal. The upstream brown coal input port 31 is formed at the upper portion of one end side (the left side of the drawing) of the upstream drying chamber 12a. The upstream 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 111is supplied to the upstream drying chamber 12a. The upstream dry coal discharge port 34 is formed at the lower portion of the other end side (the right side of the drawing) of the upstream drying chamber 12a. The brown coal which is dried at the early stage in the upstream drying chamber 12a is discharged as the dry coal from the upstream dry coal discharge port 34, and the discharged dry coal is supplied toward the downstream drying chamber 12b. The gas discharge port 35 is formed at the upper portion of the other end side of the upstream drying chamber 12a. The gas discharge port 35 discharges the steam which is produced by heating the brown coal along with the fluidizing gas supplied to the upstream drying 17 chamber 12a when drying the brown coal at the early stage. Furthermore, the fluidizing gas and the produced steam discharged from the gas discharge port 35 are supplied to a trace pipe and the like for retaining the heat of the heat retaining subject, thereby effectively utilizing the steam. The upstream heat transfer tube 33 is formed as a panel structure, and is provided inside a fluid bed 3 which is formed by fluidizing the brown coal inside the upstream drying chamber 12a. The upstream heat transfer tube 33 is connected with the affluence side of a downstream heat transfer tube (the downstream heat transfer member) 43 to be described below, and the steam (the drying steam to be described later) circulating in downstream heat transfer tube 43 is supplied as a heat medium into the pipe. The downstream drying chamber 12b of the downstream drying furnace 5b is provided with a downstream brown coal input port 41 into which the brown coal dried at the early stage is input, a downstream dry coal discharge port 44 through which the dry coal obtained by heating and drying the brown coal is discharged, a steam discharge port 45 through which the fluidizing steam and the steam produced in the drying process are discharged, and the downstream heat transfer tube 43 which heats the brown coal. The downstream brown coal input port 41 is formed at the upper portion of one end side (the left side of the drawing) of the downstream drying chamber 12b. The upstream dry coal discharge port 34 is connected to the downstream brown coal input port 41 through a fuel supply line Li. The fuel supply line Ll is provided with a rotary feeder 48. When the rotary feeder 48 is operated, the brown coal which is discharged from the upstream dry coal discharge port 34 is supplied toward the downstream brown coal input port 41. For this reason, the brown coal which 18 is supplied from the rotary feeder 48 is supplied to the downstream drying chamber 12b through the downstream brown coal input port 41. The downstream dry coal discharge port 44 is formed at the lower portion of the other end side (the right side of the drawing) of the downstream drying chamber 12b. The brown coal which is dried at the late stage in the downstream drying chamber 12b is discharged as the dry coal from the downstream dry coal discharge port 44, and the discharged dry coal is supplied toward the cooler 131. The steam discharge port 45 is formed at the upper portion of the other end side of the downstream drying chamber 12b. The steam discharge port 45 discharges the steam which is produced by heating the brown coal along with the fluidizing steam supplied to the downstream drying chamber 12b when drying the brown coal at the late stage. Furthermore, the fluidizing steam and the produced steam which are discharged from the steam discharge port 45 are supplied toward the dust collecting device 139, and are supplied to the steam compressor 135. The downstream heat transfer tube 43 is formed as a panel structure, and is provided inside the fluid bed .3 which is formed by fluidizing the brown coal inside the downstream drying chamber 12b. The downstream heat transfer tube 43 is connected with the effluence side of the steam compressor 135, and the steam which is compressed by the steam compressor 135 is supplied as the drying steam into the pipe. For this reason, when the drying steam is supplied from the steam compressor 135, the supplied drying steam flows into the downstream heat transfer tube 43. When the drying steam is supplied into the downstream heat transfer tube 43, the pipe heats the brown coal by using the latent 19 heat of the drying steam so as to remove the water content in the brown coal of the fluid bed 3 and thus to dry the brownx coal in the downstream drying chamber 12b. Subsequently, the drying steam which circulates in the downstream heat transfer tube 43 flows into the upstream heat transfer tube 33. when the drying steam is supplied into the upstream heat transfer tube 33, the pipe dries the brown coal at the early stage in the upstream drying chamber 12a by using the latent heat of the drying steam. Subsequently, the drying steam which is used for the drying process at the early stage is discharged to the outside of the upstream drying chamber 12a. Further, a gas-liquid separator 51 is provided between the upstream heat transfer tube 33 and the downstream heat transfer tube 43. The gas-liquid separator 51 is provided at the outside of the drying furnace 5, and is connected with the upstream heat transfer tube 33 and the downstream heat transfer tube 43. For this reason, a part of the effluence side of the downstream heat transfer tube 43 and a part of the inflow side of the upstream heat transfer tube 33 connected to the gas-liquid separator 51 are disposed at the outside of the drying furnace 5. The drying steam flows from the downstream heat transfer tube 43 into the gas-liquid separator 51. The gas-liquid separator 51 separates the drying steam flowing from the downstream heat transfer tube 43 into a liquid phase and a gas phase so as to supply the gas-phase drying steam to the upstream heat transfer tube 33 and to discharge the liquid phase drying steam as condensed water. The fluidizing steam supply unit 21 supplies the fluidizing steam to the upstream wind chamber lla and the downstream wind chamber 11b (a fluidizing steam supplying process). The gas supply unit 25 mixes the non-condensable 20 gas with the fluidizing steam supplied from the fluidizing steam supply unit 21 and supplies the mixture as the fluidizing gas to the upstream wind chamber lla (a fluidizing gas supplying process). The brown coal which is supplied to the upstream drying chamber 12a through the upstream brown coal input port 31 is fluidized by the fluidizing gas supplied through the upstream gas dispersion plate 6a so as to form the fluid bed 3 in the upstream drying chamber 12a and to form the freeboard F above the fluid bed 3. The flow direction of the fluid bed 3 which is formed in the upstream drying chamber 12a becomes a direction from one end side toward the other end side of the upstream drying chamber 12a. The brown coal which becomes the fluid bed 3 is heated by the upstream heat transfer tube 33, so that the water content included in the brown coal becomes the produced steam and is discharged from the gas discharge port 35 along with the fluidizing gas. The brown coal which is heated by the upstream heat transfer tube 33 is dried at the early stage by removing the water content therefrom. The brown coal which is dried at the early stage is discharged from the upstream dry coal discharge port 34. The brown coal which is discharged from the upstream dry coal discharge port 34 passes through the fuel supply line Ll by the operation of the rotary feeder 48, and is supplied to the downstream drying chamber 12b through the downstream brown coal input port 41. The brown coal which is supplied to the downstream drying chamber 12b is fluidized by the fluidizing steam supplied through the downstream gas dispersion plate 6b so as to form the fluid bed 3 in the downstream drying chamber 12b and to form the freeboard F above the fluid bed 3. The flow direction of the fluid bed 3 which is formed in the downstream drying 21 chamber 12b becomes a direction from one end side toward the other end side of the downstream drying chamber 12b. The brown coal which becomes the fluid bed 3 is heated by the downstream heat transfer tube 43, so that the water content included in the brown coal becomes the produced steam and is discharged from the steam discharge port 45 along with the fluidizing steam (a steam discharging process). The brown coal which is heated by the downstream heat transfer tube 43 is dried at the late stage by removing the water content therefrom. The brown coal which is dried at the late stage is discharged from the downstream dry coal discharge port 44. The steam which is discharged from the stem discharge port 45 is supplied to the steam compressor 135 after the dust collecting'device 139 collects dust from the pulverized coal, and is compressed by the steam compressor 135 so as to increase in temperature (a steam compressing process). The compressed steam is supplied as the drying steam to the downstream heat transfer tube 43 and circulates inside the downstream heat transfer tube 43 (a downstream steam supplying process). Subsequently, the drying steam which circulates inside the downstream heat transfer tube 43 flows into the gas-liquid separator 51. The gas-liquid separator 51 separates the drying steam into a liquid phase and a gas phase so as to discharge the liquid-phase steam as condensed water and to supply the gas-phase drying steam to the upstream heat transfer tube 33 (an upstream steam supplying process). Then, the drying steam which is supplied to the upstream heat transfer tube 33 circulates inside the upstream heat transfer tube 33, and is discharged to the outside of the drying furnace 5. Accordingly, the heat transfer tubes 33 and 43 circulate the drying steam from the downstream side toward the 22 upstream side in the flow direction of the brown coal. Next, the quality of the drying steam which circulates in the upstream heat transfer tube 33 and the downstream heat transfer tube 43 of the fluid bed drying apparatus 1 will be described by referring to FIGS. 3 and 4. FIGS. 3 and 4 are graphs illustrating the quality of the drying steam in the fluid bed drying apparatus according to the first embodiment. In the graphs illustrated in FIGS. 3 and 4, the horizontal axis indicates the quality of the drying steam and the vertical axis indicates the temperature of the drying steam. Furthermore, the quality is the ratio of the gas-phase steam with respect to the entire amount of the steam. As the quality decreases, the ratio of the gas phase steam decreases and the ratio of the liquid-phase steam increases. For this reason, since the drying steam which is compressed by the steam compressor 135 circulates in the downstream heat transfer tube 43 and then circulates in the upstream heat transfer tube 33, the high-quality drying steam flows into the downstream heat transfer tube 43, and the low-quality drying steam flows out from the upstream heat transfer tube 33. In the graphs of FIGS. 3 and 4, the mixing ratio of the non-condensable gas included in the atmosphere inside the downstream drying furnace 5b becomes 5 wt%. At this time, the pressure of the atmosphere inside the drying furnace 5 becomes 0.1 MPa. For this reason, the dew-point temperature Ti inside the downstream drying furnace 5b becomes about 100 0 C. Meanwhile, in the graph of FIG. 3, the mixing ratio of the non-condensable gas included in the atmosphere inside the upstream drying furnace 5a becomes 50 wt%. At this time, the pressure of the atmosphere inside the upstream drying furnace Sa also becomes 0.1 MPa. For 23 this reason, the dew-point temperature T2 inside the upstream drying furnace 5a becomes about 86"C. Further, in the graph of FIG. 4, the mixing ratio of the non condensable gas included in the atmosphere inside the upstream drying furnace 5a becomes 75 wt%. At this time, the pressure of the atmosphere inside the upstream drying furnace 5a also becomes 0.1 MPa. For this reason, the dew point temperature T2 inside the upstream drying furnace 5a becomes about 72 0 C. Further, in FIGS. 3 and 4, since the steam which is discharged from the downstream drying furnace 5b is compressed by the steam compressor 135 and is supplied to the downstream heat transfer tube 43, the mixing ratio of the non-condensable gas included in the drying steam which circulates in the upstream heat transfer tube 33 and the downstream heat transfer tube 43 becomes 5 wt%. At this time, each pressure inside the upstream heat transfer tube 33 and the downstream heat transfer tube 43 in which the drying steam circulates becomes 0.49 MPa. As illustrated in FIGS. 3 and 4, since the drying steam is mixed with the non-condensable gas in the fluid bed drying apparatus 1, when the quality of the drying steam decreases, the ratio of the gas-phase steam in the drying steam decreases. That is, the ratio of the gas phase non-condensable gas of the drying steam further increases. For this reason, since it is difficult to collect the latent heat from the low-quality drying steam, when the quality of the drying steam becomes smaller than 0.2, the temperature T3 of the drying steam suddenly decreases. Here, since the dew-point temperature TI inside the downstream drying furnace 5b is about 100*C, the 24 temperature T3 of the drying steam which is supplied to the downstream heat transfer tube 43 needs to be 1000C or more, and the temperature difference between the dew-point temperature T1 and the temperature T3 of the drying steam (the downstream heat transfer tube 43) becomes a predetermined temperature difference AT1. Meanwhile, since the dew-point temperature, T2 inside the upstream drying furnace 5a is about 86"C or 720C, even when the temperature T3 of the drying steam which is supplied to the upstream beat transfer tube 33 is lower than the temperature T3 of the drying steam which is supplied to the downstream heat transfer tube 43, the temperature difference between the dew-point temperature T2 and the temperature T3 of the drying steam (the upstream heat transfer tube 33) becomes a predetermined temperature difference AT2. In this way, since the temperature difference AT2 may be ensured, the brown coal may be appropriately dried at the early stage by the upstream heat transfer tube 33. Further, since the temperature difference ATl may be ensured, the brown coal may be appropriately dried at the late stage by the downstream heat transfer tube 43. As described above, according to the configuration of the first embodiment, the upstream drying chamber 12a may appropriately ensure the temperature difference AT2 between the dew-point temperature T2 and the temperature T3 of the drying steam. Accordingly, the brown coal which flows in the upstream drying chamber 12a may be dried at the early stage by the drying steam of which the ratio of the gas phase non-condensable gas is larger than that of the downstream drying chamber 12b. Meanwhile, the downstream drying chamber 12b may appropriately ensure the temperature difference AT1 between the dew-point temperature TI and the 25 temperature T3 of the drying steam. Accordingly, the brown coal which flows in the downstream drying chamber 12b may be dried at the late stage by the drying steam of which the ratio of the gas-phase non-condensable gas is smaller than that of the upstream drying chamber 12a. Accordingly, since the fluidizing gas including the non-condensable gas is supplied into the upstream drying chamber 12a, even the drying steam having a low temperature in which the ratio of the gas-phase non-condensable gas is large may appropriately dry the brown coal at the early stage. Thus, the steam may be effectively utilized and hence the latent heat of the steam may be efficiently collected. Further, according to the configuration of the first embodiment, since the drying furnace 5 may be divided into the upstream drying furnace Sa and the downstream drying furnace 5b, it is possible to suppress the fluidizing gas supplied into the upstream drying furnace Sa from being mixed into the downstream drying furnace 5b. Further, according to the configuration of the first embodiment, since the gas-liquid separator 51 discharges the liquid-phase drying steam which circulates in the downstream heat transfer tube 43 as the-condensed water, it is possible-to increase the ratio of the gas-phase component of the drying steam supplied to the upstream heat transfer tube 33. That is, the gas-liquid separator 51 may change the low-quality steam of which the ratio of the gas phase non-condensable gas is large into the high-quality steam of which the ratio of the gas-phase non-condensable gas is large. Accordingly, since it is possible to suppress the liquid-phase steam (the condensed water) from flowing into the upstream heat transfer tube 33, it is possible to suppress a liquid membrane from being formed inside the upstream heat transfer tube 33 and hence to 26 improve the heat transfer rate. Furthermore, in 'the first embodiment, the gas-liquid separator 51 is provided, but may not be provided. Furthermore, in the first embodiment, the brown coal which is dried at the early stage by the upstream drying chamber 12a is supplied to the downstream drying chamber 12b by the rotary feeder 48, but the configuration is not limited thereto. For example, the brown coal which'is dried at the early stage by the upstream drying chamber 12a may be supplied to the downstream drying chamber 12b by the screw feeder.. That is, a configuration may be employed in which a connection pipe is provided so as to connect the upstream drying chamber 12a and the downstream drying chamber 12b to each other, the screw feeder is provided inside the connection pipe, and the screw feeder is operated so as to supply the brown coal from the upstream drying chamber 12a to the downstream drying chamber 12b. [Second embodiment] Next, a fluid bed drying apparatus 200 according to a second embodiment Will be described by referring to FIG. 5. FIG. 5 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 will be described so as to avoid the repetitive description, and the same component as that of the first embodiment will be denoted by the same letter or numeral. In the fluid bed drying apparatus 1 according to the first embodiment, the drying furnace 5 is divided into the upstream drying furnace 5a and the downstream drying furnace 5b. However, in the fluid bed drying apparatus 200 according to the second embodiment, a single drying furnace 5 is provided 22 and the inside of the drying furnace 5 is divided into the upstream drying chamber 12a and the downstream drying chamber 12b. Hereinafter, the fluid bed drying apparatus 200 according to the second embodiment will be described. As illustrated in FIG. 5, the fluid bed drying apparatus 200 includes the single drying furnace 5. The drying furnace 5 has a gas dispersion plate 6 provided therein. The gas dispersion plate 6 divides a space inside the drying furnace 5 into the wind chambers 11a and l1b which are positioned at the lower side (the lower side in the drawing) in the vertical direction and the drying chambers 12a and 12b which are positioned at the upper side (the upper side in the drawing) in the vertical direction. The fluid bed drying apparatus 200 includes a drying chamber dividing member 201 which defines the drying chambers 12a and 12b and a wind chamber dividing member 202 which defines the wind chambers Ila and lb. The drying chamber dividing member 201 defines the drying chambers 12a and 12b as the upstream drying chamber 12a and the downstream drying chamber 12b in the flow direction. The upper end of the drying chamber dividing member 201 in the vertical direction is connected to the upper portion of a drying chamber 12, and the lower end thereof is provided with a gap between the lower end and the gas dispersion plate 6. For this reason, the brown coal which is dried at the early stage by the upstream drying chamber 12a passes through a gap formed by the drying chamber dividing member 201, and is introduced into the downstream drying chamber 12b. Accordingly, in the second embodiment, the upstream dry coal discharge port 34 of the first embodiment is not provided. The wind chamber dividing member 202 defines the wind chambers ala and 11b as the upstream wind chamber 1la and 28 the downstream wind chamber lb in the flow direction. The upper end of the wind chamber'dividing member 202 in the vertical direction is connected to the upper portions of the wind chambers 1la and 11b, and the lower end thereof is connected to the lower portions of the wind chambers 11a and lb. The fluid bed drying apparatus 200 includes the fluidizing steam supply unit 21 which supplies the fluidizing steam to the upstream wind chamber 11a and the downstream wind chamber 11b and the gas supply unit 25 which is connected to the supply line connecting the fluidizing steam supply unit 21 and the upstream wind chamber 1la to each other. As in the first embodiment, the fluidizing steam supply unit 21 and the gas supply unit 25 supply the fluidizing gas including the non-condensable gas and the fluidizing steam to the upstream wind chamber Ila, and supply the fluidizing steam to the downstream wind chamber l1b. The fluidizing steam supply unit 21 supplies the fluidizing steam to the upstream wind chamber 11a and the downstream wind chamber llb (a fluidizing steam supplying process). The gas supply unit 25 mixes the non-condensable gas with the fluidizing steam supplied from the fluidizing steam supply unit 21, and supplies the mixture as the fluidizing gas to the upstream wind chamber Ila (the fluidizing gas supplying process). The brown coal which is supplied to the upstream drying chamber 12a through the upstream brown coal input port 31 is fluidized by the fluidizing gas supplied through the gas dispersion plate 6 so as to form the fluid bed 3 in the upstream drying chamber 12a and to form the freeboard F above the fluid bed 3. The flow direction of the fluid bed 3 which is formed in the upstream drying chamber 12a becomes a direction from 29 one end side toward the other end side of the drying furnace 5. The brown coal which becomes the fluid bed 3 is heated by the upstream heat transfer tube 33, so that the water content included in the brown coal becomes the produced steen and is discharged from the gas discharge port 35 along with the fluidizing gas. The brown coal which is heated by the upstream heat transfer tube 33 is dried at the early stage by removing the water content therefrom. The brown coal which is dried at the early stage by the upstream drying chamber 12a passes through a gap formed by the drying chamber dividing member 201, and is introduced into the downstream drying chamber 12b. The brown coal which is introduced from the upstream drying chamber 12a into the downstream drying chamber 12b is fluidized by the fluidizing steam supplied through the gas dispersion plate 6 so as to form the fluid bed 3 in the downstream drying chamber 12b and to form the freeboard F above the fluid bed 3. As in the upstream drying chamber 12a, the flow direction of the fluid bed 3 which is formed in the downstream drying chamber 12b becomes a direction from one end side toward the other end side of the drying furnace 5. The brow. coal which becomes the fluid bed 3 is heated by the downstream heat transfer tube 43, so that the water content included in the brown coal becomes the produced steam and is discharged from the steam discharge port 45 along with the fluidizing steam (a steam discharging process). The brown coal which is heated by the downstream heat transfer tube 43 is dried at the late stage by removing the water content therefrom. The brown coal which is dried at the late stage is discharged from the downstream dry coal discharge port 44. The steam which is discharged from the steam discharge port 45 is supplied to the steam compressor 135 after the 30 dust collecting device 139 collects dust from the pulverized coal, and is compressed by the steam compressor 135 so as to increase in temperature (a steam compressing process). The compressed steam is supplied as the drying steam to the downstream heat transfer tube 43 and circulates inside the downstream beat transfer tube 43 (a downstream steam supplying process). Subsequently, the drying steam which circulates inside the downstream heat transfer tube 43 flows into the gas-liquid separator 51. The gas-liquid separator 51 separates the drying steam into a liquid phase and a gas phase so as to discharge the liquid-phase steam as condensed water and to supply the gas-phase drying steam to the upstream heat transfer tube 33 (an upstream steam supplying process). Then, the drying steam which is supplied to the upstream heat transfer tube 33 circulates inside the upstream heat transfer tube 33, and is discharged to the outside of the drying furnace 5. Accordingly, the heat transfer tube 33 circulates the drying steam from the downstream side toward the upstream side in the flow direction of the brown coal. As described above, even in the configuration of the second embodiment, the upstream dryingsohamber 12a may appropriately ensure the temperature difference AT2 between the dew-point temperature T2 and the temperature T3 of the drying steam. Accordingly, the brown coal which flows in the upstream drying chamber 12a may be dried at the early stage by the drying steam of which the ratio of the gas phase non-condensable gas is larger than that of the downstream drying chamber 12b. Meanwhile, the downstream drying chamber 12b may appropriately ensure the temperature difference ATI between the dew-point temperature TI and the temperature T3 of the drying steam. Accordingly, the brown coal which flows in the downstream drying chamber 12b may 31 be dried at the late stage by the drying steam of which the ratio of the gas-phase non-condensable gas is smaller than that of the upstream drying chamber 12a. Accordingly, since the fluidizing gas including the non-condensable gas is supplied into the upstream drying chamber 12a, even the drying steam having a temperature in which the ratio of the gas-phase non-condensable gas is large may appropriately dry the brown coal at the early stage. Thus, the steam may be effectively utilized and hence the latent heat of the steam may be efficiently collected. Further, according to the configuration of the second embodiment, since the single drying furnace 5 may be formed by using the drying chamber dividing member 201, the configuration of the fluid bad drying apparatus 200 may be simplified. Furthermore, the invention is not limited to the configurations of the first and second embodiments, and the configurations of the first to sixth modified examples may be employed. Hereinafter, the first to sixth modified examples will be described. Furthermore, the configurations of the first to. sixth modified examples are applied to the first embodiment, but may be applied to the second embodiment. FIG. 6 is a schematic configuration diagram roughly illustrating a fluid bed drying apparatus according to a first modified example. FIG. 7 is a schematic configuration diagram roughly illustrating a fluid bed drying apparatus according to a second modified example. FIG. B is a schematic configuration diagram roughly illustrating a fluid bed drying apparatus according to a third modified example. FIG. 9 is aschematic configuration diagram roughly illustrating a fluid bed drying apparatus according to a fourth modified example. FIG. 10 is a schematic configuration diagram roughly 32 illustrating a fluid bed drying apparatus according to a fifth modified example. FIG. 11 is a schematic configuration diagram roughly illustrating a fluid bed drying apparatus according to a sixth modified example. As illustrated in FIG. 2, in the fluid bed drying apparatus 1 of the first embodiment, the steam which is discharged from the steam discharge port 45 formed at the upper portion of the other end side of the downstream drying chamber 12b is supplied to the steam compressor 135 through the dust collecting device 139, and the steam'which is compressed by the compressor 135 is supplied as the drying steam to the downstream heat transfer tube 43. However, as illustrated in FIG. 6, in the fluid bed drying apparatus 1 of the first modified example, the steam which is discharged from the downstream drying chamber 12b is compressed by the compressor 135 through the dust collecting device 139, a part of the drying steam supplied to the downstream heat transfer tube 43 is extracted, and the steam may be supplied as the fluidizing steam to the downstream wind chamber lb. With such a configuration, in the fluid bed drying apparatus 1 of the first modified example, it is possible to decrease the amount of the steam supplied from the outside. Further, as illustrated in FIG. 7, in the fluid bed drying apparatus 1 of the second modified example, the supply line for supplying the steam to the downstream wind chamber lb is connected to the supply line for supplying the steam discharged from the downstream drying chamber 12b to the compressor 135 through the dust collecting device 139. Then, a boosting blower 210 is provided in the supply line for supplying the steam to the downstream wind chamber 1lb and the compressed steam may be supplied to the downstream wind chamber 1lb by the boosting blower 210. With such a configuration, in the 33 fluid bed drying apparatus 1 of the second modified example, it is possible to decrease the power of the compressor 135. Further, as illustrated in FIG. 8, in the fluid bed drying apparatus 1 of the third modified example, the steam which is discharged from the downstream drying chamber 12b is compressed by the compressor 135 through the dust collecting device 139, a part of the drying steam supplied to the downstream heat transfer tube 43 is extracted, and the steam may be input as the fluidizing steam to the upstream wind chamber 1la and the downstream wind chamber 11b. With such a configuration, in the fluid bed drying apparatus 1 of the third modified example, it is possible to decrease the amount of the steam supplied from the outside. Further, as illustrated in FIG. 9, in the fluid bed drying apparatus 1 of the fourth modified example, the supply line for supplying the steam to the downstream wind chamber lb is connected to the supply line for supplying the steam discharged from the downstream drying chamber 12b to the compressor 135 through the dust collecting device 139, and the supply line for supplying the steam to the upstream.wind chamber 11a is connected to the supply line for supplying the steam to the downstream wind chamber 1lb. Then, the boosting blower 210 is provided in the supply line for supplying the steam to the downstream wind chamber 1Ib, and the compressed steam may be supplied to the downstream wind chamber lb and the upstream wind chamber 11a by the boosting blower 210. With such a configuration, in the fluid bed drying apparatus 1 of the fourth modified example, it is possible to decrease the power of the compressor 135. Further, as illustrated in FIG. 10, in the fluid bed drying apparatus 1 of the fifth modified example, in addition to the configuration of the first modified example, 34 a circulation line is provided which connects the gas discharge port 35 formed at the upper portion of the other end side of the upstream drying chamber 12a to the supply line supplying the fluidizing steam from the fluidizing steam supply unit 21 to the upstream wind chamber 11a, and the circulation line is provided with a boosting blower 211. Then, the produced steam and the fluidizing gas of which the ratio of the gas-phase non-condensable gas discharged from the gas discharge port 35 of the upstream drying chamber 12a is large are supplied to the upstream wind chamber 11a by the boosting blower 211 along with the fluidizing steam from the fluidizing steam supply unit 21. With such a configuration, in the fluid bed drying apparatus 1 of the fifth modified example, a gas supply unit 22 does not need to be provided, and hence the configuration or the cost of the apparatus may be decreased. Further, as illustrated in FIG. 11, in the fluid bed drying apparatus 1 of the sixth modified example, the configuration of the second modified example is combined with the configuration of the fifth modified example. That is, in the fluid bed drying apparatus 1 of the sixth modified example, in addition to the configuration of the fifth modified example, the supply line for supplying the steam to the downstream wind chamber lb is connected to the supply line for supplying the steam discharged from the downstream drying chamber 12b to the compressor 135 through the dust collecting device 139. Then, the boosting blower 210 is provided in the supply line for supplying the steam to the downstream wind chamber lb, and the compressed steam may be supplied to the downstream wind chamber 1lb by the boosting blower 210. With such a configuration, in the fluid bed drying apparatus 1 of the sixth modified example, the power of the compressor 135 may be decreased.

35 According to the configuration of the embodiments, the wet fuel of the upstream drying chamber may be heated by the upstream heat transfer member in which the low-quality steam of which the ratio of the gas-phase non-condensable gas is large circulates while being fluidized by the fluidizing steam of which the content ratio of the non condensable gas is large. Meanwhile, the wet fuel of the downstream drying chamber may be heated by the downstream heat transfer member in which the high-quality steam of which the ratio of the gas-phase non-condensable gas is small circulates while being fluidized by the fluidizing steam. For this reason, since the fluidizing steam of which the content ratio of the non-condensable gas is large is used in the upstream drying chamber, the dew-point temperature inside the upstream drying chamber may be decreased, and hence the wet fuel flowing inside the upstream drying chamber may be also dried at a low temperature by the amount in which the dew-point temperature decreases. Accordingly, since even the low quality steam may appropriately dry the wet fuel in the upstream drying chamber, the low-quality steam may be effectively utilized and hence the latent heat of the steam may be efficiently collected. In this case, the drying furnace may be divided into an upstream drying furnace which forms the upstream drying chamber and a downstream drying furnace which forms the downstream drying chamber. According to the configuration of the embodiments, since the drying furnace may be divided into the upstream drying furnace and the downstream drying furnace, it is possible to suppress the fluidizing gas supplied into the upstream drying furnace from being mixed with the downstream drying furnace.

36 In this case, the drying furnace may include a defining plate which defines the inside of the drying furnace as the upstream drying chamber and the downstream drying chamber. According to the configuration of the embodiments, since it is possible to define the drying furnace as the upstream drying chamber and the downstream drying chamber by the defining plate, the configuration of the drying furnace may be simplified. In this case, the fluid bed drying apparatus may further include a gas-liquid separating device which separates the steam flowing from the downstream heat transfer member so as to supply gas-phase steam to the upstream heat transfer member and to discharge liquid-phase steam as condensed water. According to the configuration of the embodiments, since the gas-liquid separating device discharges the liquid-phase steam circulating in the downstream heat transfer member as the condensed water, it is possible to increase the ratio of the gas-phase component of the steam supplied to the upstream heat transfer member. That is, the gas-liquid separating device may change the low-quality steam of which the ratio of the gas-phase non-condensable gas is large into the high-quality steam of which the ratio of the gas-phase non-condensable gas is large. Accordingly, since it is possible to suppress the liquid-phase steam from flowing into the upstream heat transfer member, it is possible to suppress a liquid membrane from being formed inside the upstream heat transfer member and hence to improve the heat transfer rate. According to the configuration of the embodiments, there is provided a gasification combined power generating facility including: the above-described fluid bed drying 37 apparatus; a gasifying furnace which treats the dried wet fuel supplied from the fluid bed drying apparatus so.that the wet fuel is changed into a gasifying gas;. a gas turbine which is operated by using the gasifying gas as a 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 the configuration of the embodiments, since it is possible to improve the efficiency of collecting the latent heat of the steam in the fluid bed drying apparatus, it is possible to effectively utilize the latent heat and hence to improve the power generation efficiency of the generator connected to the steam turbine. According to the configuration of the embodiments, the wet fuel of the upstream drying chamber may be heated by the upstream heat transfer member in which the low-quality steam of which the ratio of the gas-phase non-condensable gas is large circulates while being fluidized by the fluidizing steam of which the content ratio of the non condensable gas is large. Meanwhile, the wet fuel of the downstream drying chamber may be heated by the downstream heat transfer member in which the high-quality steam of which the ratio of the gas-phase non-condensable gas is small circulates while being fluidized by the fluidizing steam. For this reason, since the fluidizing steam of which the content ratio of the non-condensable gas is large is used in the upstream drying chamber, the dew-point temperature inside the upstream drying chamber may be decreased, and hence the wet fuel flowing inside the upstream drying chamber may be also dried at a low temperature by the amount in which the dew-point temperature decreases. Accordingly, since even the low- 38 quality steam may appropriately dry the wet fuel in the upstream drying chamber, the low-quality steam may be effectively utilized and hence the latent heat of the steam may be efficiently collected. According to the embodiments of the fluid bed drying apparatus, the gasification combined power generating facility, and the drying method of the invention, since the wet fuel may be appropriately dried by the low-quality steam of which the ratio of the gas-phase non-condensable gas is large, it is possible to effectively utilize the low-quality steam and hence to efficiently collect the latent beat of the steam.

Claims

1. A fluid bed drying apparatus comprising: a drying furnace into which a wet fuel is supplied; a fluidizing steam supply unit for supplying fluidizing steam to the drying furnace and fluidizes the wet fuel so as to form a fluid bed inside the drying furnace; a heat transfer member provided inside the drying furnace for heating the supplied wet fuel; and a compressor for compressing the steam discharged from the drying furnace and supplying the compressed steam toward the heat transfer member, wherein the drying furnace includes: an upstream drying chamber provided at the upstream side of the flow direction of the wet fuel and a downstream drying chamber provided at the downstream side of the upstream drying chamber, wherein the heat transfer member includes: an upstream heat transfer member provided in the upstream drying chamber and a downstream heat transfer member provided in the downstream drying chamber, so that the steam supplied from the compressor circulates in the downstream heat transfer member and then circulates in the upstream heat transfer member, wherein the compressor is configured to compress the steam discharged from the downstream drying chamber, and wherein the fluidizing steam supply unit is configured to supply the fluidizing steam to the upstream drying chamber and the downstream drying chamber, and supply the fluidizing steam of which a content ratio of a non condensable gas is larger than that of the downstream drying chamber to the upstream drying chamber. 40

2. The fluid bed drying apparatus according to claim 1, wherein the drying furnace is divided into an upstream drying furnace for forming the upstream drying chamber and a downstream drying furnace for forming the downstream drying chamber.

3. The fluid bed drying apparatus according to claim 1, , wherein the drying furnace includes a defining plate for defining the inside of the drying furnace as the upstream drying chamber and the downstream drying chamber.

4. The fluid bed drying apparatus according to any one of claims 1 to 3, further comprising: a gas-liquid separating device for separating the steam flowing from the downstream heat transfer member so as to supply gas-phase steam to the upstream heat transfer member and to discharge liquid-phase steam as condensed water.

5. A gasification combined power generating facility comprising: the fluid bed drying apparatus according to any one of claims 1 to 4; a gasifying furnace for treating the dried wet fuel supplied from the fluid bed drying apparatus so that the wet fuel is changed into a gasifying gas;. a gas turbine operated by using the gasifying gas as a fuel; a steam turbine 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 41 the steam turbine.

6. A drying method of drying a wet fuel by heating the wet fuel using a heat transfer member provided inside a drying furnace while circulating the wet fuel supplied into the drying furnace using fluidizing steam, wherein the drying furnace includes: an upstream drying chamber provided at the upstream side of the flow direction of the wet fuel, and a downstream drying chamber provided at the downstream side of the upstream drying chamber, wherein the heat transfer member includes: an upstream heat transfer member provided in the upstream drying chamber, and a downstream heat transfer member provided in the downstream drying chamber, and wherein the drying method comprises: supplying the fluidizing steam to the upstream drying chamber and the downstream drying chamber; supplying the fluidizing steam of which a content ratio of a non-condensable gas is larger than that of the downstream drying chamber as a fluidizing gas to the upstream drying chamber; discharging steam produced when drying the wet fuel from the downstream drying chamber; compressing the steam discharged in the discharging of steam; supplying the steam compressed in the compressing of steam to the downstream heat transfer member; and supplying the steam circulating in the downstream heat transfer member to the upstream heat transfer member. 42

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

8. 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 drawings and/or examples.

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