AU2013201098B2 - Fluid bed drying apparatus, gasification combined power generating facility, and drying method - Google Patents

Abstract

Provided are a fluid bed drying apparatus including: a drying furnace for fluidizing a wet fuel by fluidizing steam so as to form a fluid bed therein; a heat transfer member provided inside the drying furnace for heating the wet fuel; and a compressor for compressing steam discharged from the drying furnace so as to supply the compressed steam to the heat transfer member, wherein the heat transfer member is configured to circulate the steam supplied from the compressor from the downstream side toward the upstream side in the flow direction of the wet fuel. uJ ow 'co z < 0 r co~oD L& U g rl I -4 I LO m -

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 042231 filed February 28, 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 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 Patent Application Laid-Open 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, particularly when a drying subject is a powder, it is difficult to eliminate the 2 possibility of the mixture of a non-condensable gas such as air including nitrogen by a heat exchanging (drying) process. 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 (the ratio of the gas-phase steam with respect to the entire amount of the steam) of the steam 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 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, the low-quality steam of which the temperature of the steam decreases is not effectively utilized and hence it is difficult to improve the efficiency of collecting the latent heat. Any discussion of the prior art throughout the 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 "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".

2a SUMMARY OF THE INVENTION According to a first aspect of the invention, there is provided a fluid bed drying apparatus including: a drying furnace for fluidizing a wet fuel by fluidizing steam so as to form a fluid bed therein; a heat transfer member provided inside the drying furnace for heating the wet fuel; and a compressor for compressing steam discharged from the drying furnace so as to supply the compressed steam to the heat transfer member, wherein the heat transfer member is configured to circulate the steam supplied from the compressor from the downstream side 3 toward the upstream side in the flow direction of the wet fuel. According to a second aspect of the 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 beat recovery boiler into which a turbine exhaust gas is introduced from the gas turbine; and a generator connected to the gas turbine and the steam turbine. According to a third aspect of the 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 heat transfer member includes; an upstream heat transfer member provided at the upstream side in the flow direction of the wet fuel; and a downstream heat transfer member provided at the downstream side of the upstream heat transfer member, and wherein the drying method includes: discharging steam produced when drying the wet fuel from the drying furnace; compressing the steam discharged in the discharging of the steam; supplying the steam compressed in the compressing of the steam to the downstream heat transfer member; and separating the steam flowing from the downstream heat transfer member in the supplying of the downstream steam into a gas and a liquid so as to discharge the liquid-phase steam as condensed water and to supply the gas-phase steam to the upstream heat transfer member.

4 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 drying steam in the fluid bed drying apparatus according to the first embodiment; FIG. 4 is a schematic configuration diagram roughly illustrating a fluid bed drying apparatus according to a second embodiment; FIG. 5 is a schematic configuration diagram roughly illustrating a fluid bed drying apparatus according to a third embodiment; FIG. 6 is a schematic configuration diagram roughly illustrating a fluid bed drying apparatus according to a fourth embodiment; FIG. 7 is a schematic configuration diagram roughly illustrating a fluid bed drying apparatus according to a fifth embodiment; and FIG. 8 is a schematic configuration diagram roughly illustrating a fluid bed drying apparatus according to a sixth 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. However, the invention is not limited to the following embodiments.

5 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 embodiments of the present invention to provide a fluid bed drying apparatus, a gasification combined power generating facility, and a drying method capable of improving the efficiency of collecting latent beat of steam by effectively utilizing steam of which a ratio of a gas-phase non-condensable gas is large. [First embodiment] FIG. I 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 6 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 Ill 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 below 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 a heat transfer pipe 33. 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 7 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 pipe 33 of the fluid bed drying apparatus 1. 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 into 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 (compressor 161) so that the air compressed by the gas turbine facility 117 may be supplied thereto. A air separating device 142 is used to produce separate nitrogen and oxygen from the air in the atmosphere, a first 8 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 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.

9 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 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. 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 (I 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 10 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 exhaust 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 exhaust 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 exhaust 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 exhaust gas is discharged from a stack 175 to the atmosphere.

11 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 exhaust gas which is discharged from the fluid bed drying apparatus l 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 pipe 33 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 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 12 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 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 13 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 exhaust 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 exhaust gas which is purified by removing the toxic material of the exhaust 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 brown coal is supplied and a gas dispersion plate 6 which is 14 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 wind 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 fluidizing steam (moisture vapor) is introduced into the wind chamber 11. The inside of the drying chamber 12 of the drying furnace 5 is divided into a preheating region 12a and a drying region 12b. The preheating region 12a is provided at one end side (the left side of the drawing) inside the drying chamber 12, the drying region 12b is provided at the other end side (the right side of the drawing) of the drying chamber 12, and the preheating region 12a becomes a region smaller than the drying region 12b. The preheating region 12a is a region which preheats the brown coal input into the drying chamber 12, and the drying region 12b is a region which dries the brown coal input into the drying chamber 12. Here, the fluidizing steam is introduced into the drying chamber 12 through the wind chamber 11. Then, since the brown coal is dried in the drying region 12b, the temperature of the wet fuel inside the drying chamber 12 at the drying region 12b is equal to the dew-point temperature of the atmosphere and becomes about 100*C. Meanwhile, since the brown coal may be preheated in the preheating region 12a, the temperature of the wet fuel inside the drying chamber 12 at the preheating region 12a is smaller than lOOC. The drying chamber 12 of the drying furnace 5 is provided with a brown coal input port 31 through which the 15 brown coal is input, a dry coal discharge port 34 through which the dry coal obtained by heating and drying the brown coal is discharged, a steam discharge port 35 from which the fluidizing steam and the steam produced in the drying process are discharged, and the heat transfer pipe (the heat transfer member) 33 which heats the brown coal. The brown coal input port 31 is formed at the upper portion of one end side (the left side of the drawing) of the preheating region 12a of the drying chamber 12. The coal supply device 111 is connected to the brown coal input port 31, and the brown coal which is supplied from the coal supply device 111 is supplied to the preheating region 12a of the drying chamber 12. The dry coal discharge port 34 is formed at the lower portion of the other end side (the right side of the drawing) of the drying region 12b 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 34, and the discharged dry coal is supplied toward the cooler 131. The steam discharge port 35 is formed at the upper portion of the other end side of the drying region 12b of the drying chamber 12. The steam discharge port 35 discharges the steam which is produced by heating the brown coal along with the fluidizing steam supplied to the drying chamber 12 when drying the brown coal. Furthermore, the fluidizing steam and the produced steam which are discharged from the steam discharge port 35 are supplied toward the dust collecting device 139 described above, and are supplied to the steam compressor 135. The heat transfer pipe 33 includes an upstream heat transfer pipe (an upstream heat transfer member) 33a which is provided in the preheating region 12a and a downstream 16 heat transfer pipe (a downstream heat transfer member) 33b which is provided in the drying region 12b. The upstream heat transfer pipe 33a and the downstream heat transfer pipe 33b are respectively formed as panel structures, and are provided inside the flowing brown coal. The heat transfer pipe 33 is connected with the outflow 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. Specifically, the outflow side of the steam compressor 135 is connected with the inflow side of the downstream heat transfer pipe 33b, and the outflow side of the downstream heat transfer pipe 33b is connected with the inflow side of the upstream heat transfer pipe 33a. For this reason, when the drying steam is supplied from the steam compressor 135, the supplied drying steam flows into the downstream heat transfer pipe 33b. When the drying steam is supplied into the downstream heat transfer pipe 33b, the pipe heats the brown coal by using the latent heat of the drying steam so as to remove the water content in the brown coal of a fluid bed 3 and thus to dry the brown coal in the drying region 12b of the drying chamber 12. Subsequently, the drying steam which circulates in the downstream heat transfer pipe 33b flows into the upstream heat transfer pipe 33a. When the drying steam is supplied into the upstream heat transfer pipe 33a, the pipe preheats the brown coal in the preheating region 12a of the drying chamber 12 by using the latent heat of the drying steam. Subsequently, the drying steam which is used for the preheating process is discharged to the outside of the drying chamber 12. Further, a gas-liquid separator 41 is provided between the upstream heat transfer pipe 33a and the downstream heat transfer pipe 33b, and the gas-liquid separator 41 is 17 connected with the upstream heat transfer pipe 33a and the downstream heat transfer pipe 33b. The gas-liquid separator 41 is provided at the outside of the drying furnace S. For this reason, a part of the outflow side of the downstream heat transfer pipe 33b and a part of the inflow side of the upstream heat transfer pipe 33a connected to the gas-liquid separator 41 are disposed at the outside of the drying furnace 5. The drying steam flows from the downstream heat transfer pipe 33b into the gas-liquid separator 41. The gas-liquid separator 41 separates the drying steam which flows from the downstream heat transfer pipe 33b into a liquid phase and a gas phase so as to supply the gas-phase drying steam to the upstream heat transfer pipe 33a and to discharge the liquid-phase drying steam as the condensed water. Accordingly, the brown coal which is supplied to the preheating region 12a of the drying chamber 12 through the brown coal input port 31 is fluidized by the fluidizing steam supplied through the gas dispersion plate 6, so that the fluid bed 3 is formed in the entire area inside the drying chamber 12 and the freeboard F is formed above the fluid bed 3. The flow direction of the fluid bed 3 which is formed in the drying chamber 12 becomes a direction from one end side toward the other end side of the drying chamber 12. The brown coal which is input to the preheating region 12a is preheated by the upstream heat transfer pipe 33a so as to increase in temperature. The brown coal which increases in temperature flows in the flow direction, and is input to the drying region 12b. The brown coal which is input to the drying region 12b is preheated by the downstream heat transfer pipe 33b, so that the water content included in the brown coal becomes the produced steam and is discharged from the steam discharge 18 port 35 along with the fluidizing steam (a steam discharging process). The steam which is discharged from the steam discharge port 35 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 pipe 33b, and circulates in the downstream heat transfer pipe 33b (a downstream steam supplying process). Subsequently, the drying steam which circulates in the downstream heat transfer pipe 33b flows into the gas-liquid separator 41. The gas-liquid separator 41 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 pipe 33a (a gas-liquid separating process). Then, the drying steam which is supplied to the upstream heat transfer pipe 33a circulates in the upstream heat transfer pipe 33a, and is discharged to the outside of the drying furnace 5. Accordingly, the heat transfer pipe 33 circulates the drying steam from the downstream side toward the upstream side in the flow direction of the brown coal. Next, the quality of the drying steam which circulates in the heat transfer pipe 33 of the fluid bed drying apparatus 1 will be described by referring to FIG. 3. FIG. 3 is a graph illustrating the quality of the drying steam in the fluid bed drying apparatus according to the first embodiment. In the graph illustrated in FIG. 3, 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 19 gas-phase steam with respect to the entire amount of the steam, where as the quality decreases, the ratio of the gas-phase steam decreases and the ratio of the liquid-phase steam increases. Accordingly, the drying steam which is supplied to the heat transfer pipe 33 circulates in the downstream heat transfer pipe 33b and circulates in the upstream heat transfer pipe 33a, so that the high-quality drying steam becomes the inflow side of the downstream heat transfer pipe 33b and the low-quality drying steam becomes the outflow side of the upstream heat transfer pipe 33a. The graph of FIG. 3 illustrates a case in which the mixture ratio of the non-condensable gas included in, the atmosphere inside the drying furnace 5 is 5 wt%- At this time, the pressure of the atmosphere inside the drying furnace 5 becomes 0.1 MPa. Further, the temperature Ti of the brown coal in the drying region 12b of the drying furnace 5 is equal to the dew-point temperature inside the drying furnace 5 and becomes about 100"C. Further, in FIG. 3, the steam which is discharged from the drying furnace 5 is recompressed by the steam compressor 135 and is supplied to the heat transfer pipe 33, so that the mixture ratio of the non-condensable gas included in the drying steam circulating in the heat transfer pipe 33 becomes 5. wt%. At this time, the pressure inside the heat transfer pipe 33 in which the drying steam circulates becomes 0.49 MPa. As illustrated in FIG. 3, the non-condensable gas is mixed with the drying steam in the fluid bed drying apparatus 1. For this reason, when the quality of the drying steam decreases, the ratio of the gas-phase steam of the drying steam decreases, and hence the ratio of the gas phase non-condensable gas of the drying steam increases. For this reason, when the quality of the drying steam 20 becomes smaller than 0-2, the temperature T2 of the drying steam suddenly decreases, and hence it is difficult to collect the latent heat from the low-quality drying steam. In the drying region 12b, since the temperature TI of the brown coal inside the drying furnace 5 is about 1000C, the temperature T2 of the drying steam which is supplied to the downstream heat transfer pipe 33b needs to be 100"C or more, and hence the temperature difference between the temperature TI of the brown coal and the temperature T2 of the drying steam (the downstream heat transfer pipe 33b) becomes a predetermined temperature difference ATI. Meanwhile, since the brown coal is mainly preheated in the preheating region 12a, the temperature T2 of the drying steam which is supplied to the upstream heat transfer pipe 33a may be higher than the temperature T3 of the brown coal. For this reason, the temperature difference between the temperature T3 of the brown coal and the temperature T2 of the drying steam at the preheating region 12a becomes a predetermined temperature difference AT2. At this time, the predetermined temperature difference AT2 becomes higher than the predetermined temperature difference AT1. Accordingly, the steam temperature T2 of the upstream heat transfer pipe 33a is lower than that of the drying region 12b, but since the predetermined temperature difference AT2 may be ensured, the brown coal in the preheating region 12a may be appropriately preheated. Further, the steam temperature T2 of the downstream heat transfer pipe 33b may be higher than that of the preheating region 12a. Accordingly, the downstream heat transfer pipe 33b may appropriately heat and dry the brown coal in the drying region 12b while ensuring the predetermined temperature difference AT1.

21 As described above, according to the configuration of the first embodiment, the brown coal which circulates in the preheating region 12a may be preheated by the drying steam of which the ratio of the gas-phase non-condensable gas is larger than that of the drying region 12b. Meanwhile, the brown coal which circulates in the drying region 12b may be heated and dried by the drying steam of which the ratio of the gas-phase non-condensable gas is smaller than that of the preheating region 12a. At this time, the preheating region 12a may appropriately ensure the temperature difference AT2 between the temperature T3 of the brown coal and the temperature T2 of the drying steam. Accordingly, since the ratio of the gas-phase non condensable gas is large, even when the temperature of the drying steam decreases, the brown coal may be appropriately preheated. For this reason, the steam may be effectively utilized and the latent heat of the steam may be efficiently collected. Further, according to the configuration of the first embodiment, since the liquid-phase drying steam which circulates in the downstream heat transfer pipe 33b is discharged as the condensed water by the gas-liquid separator 41, the ratio of the gas phase of the drying steam which is supplied to the upstream heat transfer pipe 33a may be increased. That is, the low-quality steam of which the ratio of the gas-phase non-condensable gas is large may be changed to the high-quality steam of which the ratio of the gas-phase non-condensable gas is large by the gas-liquid separator 41. Accordingly, since it is possible to suppress the liquid-phase steam (the condensed water) from flowing into the upstream heat transfer pipe 33a, it is possible to.suppress the liquid membrane from being formed inside the upstream heat transfer pipe 33a and hence 22 to improve the heat transfer rate. Furthermore, in the first embodiment, the gas-liquid separator 41 is provided, but the gas-liquid separator 41 may not be provided. [Second embodiment] Next, a fluid bed drying apparatus 200 according to a second 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 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 heat transfer pipe 33 includes the upstream heat transfer pipe 33a and the downstream heat transfer pipe 33b, but in the fluid bed drying apparatus 200 according to the second embodiment, a heat transfer pipe 201 is provided in the entire area of the preheating region 12a and the drying region 12b. Hereinafter, the fluid bed drying apparatus 200 according to the second embodiment will be described. As illustrated in FIG. 4, in the fluid bed drying apparatus 200 of the second embodiment, the inside of the drying chamber 12 of the drying furnace 5 is divided into the preheating region 12a and the drying region 12b. A pair of steam chambers 202a and 202b is provided at both sides of the drying furnace 5 in the flow direction, and the plurality of heat transfer pipes 201 are laid between the pair of steam chambers 202a and 202b. For this reason, the plurality of heat transfer pipes 201 are arranged in the entire area of the preheating region 12a and the drying region 12b.

23 In the plurality of heat transfer pipes 201, one ends (the left side of the drawing) are connected to the steam chamber 202a and the other ends (the right side of the drawing) are connected to the steam chamber 202b. In the pair of steam chambers 202a and 202b, one steam chamber 202a is provided at the outside of one end side (the left side of the drawing) of the drying furnace, and the other steam chamber 202b is provided at the outside of the other end side (the right side of the drawing) of the drying furnace. For this reason, the plurality of heat transfer pipes 201 are arranged so as to penetrate the drying furnace 5 in the flow direction. Further, the other steam chamber 202b is connected with the steam compressor 135, and the steam which is compressed by the steam compressor 135 flows thereinto as the drying steam. Accordingly, when the drying steam is supplied from the steam compressor 135, the supplied drying steam flows into the other steam chamber 202b. The drying steam which flows into the other steam chamber 202b is supplied to the plurality of heat transfer pipes 201 connected to the other steam chamber. The drying steam which is supplied to the plurality of heat transfer pipes 201 circulates in the drying region 12b. The drying steam which circulates in the drying region 12b heats the brown coal by using the latent heat so as to remove the water content in the brown coal of the fluid bed 3 and thus to dry the brown coal in the drying region 12b of the drying chamber 12. Subsequently, the drying steam circulates in the preheating region 12a. The drying steam which circulates in the preheating region 12a preheats the brown coal by using the latent heat. As described above, according to the configuration of the second embodiment, the brown coal which circulates in 24 the preheating region 12a may be preheated by the drying steam of which the ratio of the gas-phase non-condensable gas is larger than that of the drying region 12b. Meanwhile, the brown coal which circulates in the drying region 12b may be heated and dried by the drying steam of which the ratio of the gas-phase non-condensable gas is smaller than that of the preheating region 12a. Accordingly, even when the temperature of the drying steam decreases, the temperature difference AT2 may be ensured. For this reason, the brown coal may be appropriately preheated and hence the latent heat of the steam may be efficiently collected. [Third embodiment] Next, a fluid bed drying apparatus 210 according to a third 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 third embodiment. Furthermore, even in the third 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 brown coal in the preheating region 12a of the drying chamber 12 is preheated, but in the fluid bed drying apparatus 210 according to the third embodiment, the brown coal in the raw coal bunker 121 of the coal supply device (the fuel supply device) 111 is preheated. Hereinafter, the fluid bed drying apparatus 210 according to the third embodiment will be described. As illustrated in FIG. 5, in the fluid bed drying apparatus 210 of the third embodiment, the inside of the 25 drying chamber 12 of the drying furnace 5 becomes the drying region 12b. For this reason, the brown coal input port 31 is formed at the upper portion of one end side (the left side of the drawing) of the drying region 12b of the drying chamber 12. The heat transfer pipe 33 is formed as a panel structure, and is provided inside the brown coal which flows in the drying region 12b. The heat transfer pipe 33 is connected with the outflow 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. The heat transfer pipe 33 circulates the drying steam from the downstream side toward the upstream side in the flow direction of the brown coal. Further, the raw coal bunker 121 is provided with a preheating heat transfer pipe (preheating heat transfer member) 211. The preheating heat transfer pipe 211 is formed as a panel structure like the heat transfer pipe 33, and is provided inside the raw coal banker 121. The preheating heat transfer pipe 211 is connected with the outflow side of the heat transfer pipe 33, and the drying steam which circulates in the heat transfer pipe 33 is supplied into the pipe. Further, the gas-liquid separator 41 is provided between the heat transfer pipe 33 and the preheating heat transfer pipe 211, and the gas-liquid separator 41 is connected with the heat transfer pipe 33 and the preheating heat transfer pipe 211. Furthermore, even in the third embodiment, since the gas-liquid separator 41 has substantially the same configuration as those of the first and second embodiments, the description thereof will not be repeated. Accordingly, when the drying steam is supplied from 26 the steam compressor 135, the supplied drying steam flows into the heat transfer pipe 33. When the drying steam is supplied into the heat transfer pipe 33, the pipe heats the brown coal by using the latent 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 brown coal in the drying region 12b of the drying chamber 12. Subsequently, the drying steam which circulates in the heat transfer pipe 33 flows into the preheating heat transfer pipe 211. When the, drying steam is supplied into the preheating heat transfer pipe 211, the pipe preheats the brown coal stored inside the raw coal bunker 121 by using the latent heat of the drying steam. Subsequently, the drying steam which is used for the preheating process is discharged to the outside of the raw coal bunker 121. As described above, according to the configuration of the third embodiment, the brown coal which is stored inside the raw coal bunker 121 may be preheated by the drying steam of which the ratio of the gas-phase non-condensable gas is larger than that of the heat transfer pipe 33. Meanwhile, the brown coal which flows in the drying region 12b may be heated and dried by the drying steam of which the ratio of the gas-phase non-condensable gas is smaller than that of the drying steam which is used for the preheating process inside the raw coal bunker 121. Accordingly, even when the temperature of the drying steam decreases, since it is possible to ensure the temperature difference AT2 with respect to the brown coal to be input to the fluid bed drying apparatus 210, it is possible to appropriately preheat the brown coal and hence to efficiently collect the latent heat of the steam. Furthermore, in the third embodiment, the brown coal which is stored in the raw coal bunker 121 is preheated.

27 However, a fuel storage hopper may be separately provided between the crusher 123 and the fluid bed drying apparatus 1 and the preheating heat transfer pipe 211 may be provided inside the fuel storage hopper. [Fourth embodiment] Next, a fluid bed drying apparatus 220 according to a fourth embodiment will be described by referring to FIG. 6. FIG. 6 is a schematic configuration diagram roughly illustrating the fluid bed drying apparatus according to the fourth embodiment. Furthermore, even in the fourth 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 steam of which the ratio of the gas-phase non condensable gas is large is used to preheat the brown coal, but in the fluid bed drying apparatus 220 according to the fourth embodiment, the drying steam of which the ratio of the gas-phase non-condensable gas is large is used to heat the steam discharged from the steam discharge port 35. Hereinafter, the fluid bed drying apparatus 220 according to the fourth embodiment will be described. As illustrated in FIG. 6, in the fluid bed drying apparatus 220 of the fourth embodiment, the inside of the drying chamber 12 of the drying furnace 5 becomes the drying region 12b. For this reason, the brown coal input port 31 is formed at the upper portion of one end side (the left side of the drawing) of the drying region 12b of the drying chamber 12. The heat transfer pipe 33 is formed as a panel structure, and is provided inside the brown coal which 28 flows in the drying region 12b. The heat transfer pipe 33 is connected with the outflow 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. The heat transfer pipe 33 circulates the drying steam from the downstream side toward the upstream side in the flow direction of the brown coal. Further, the drying chamber 12 is provided with a steam heating heat transfer pipe (steam heating heat transfer member) 221. The steam heating heat transfer pipe 221 is formed as a panel structure like the heat transfer pipe 33, and is provided near the steam discharge port 35 of the drying chamber 12. The steam heating heat transfer pipe 221 is connected with the outflow side of the heat transfer pipe 33, and the drying steam which circulates in the heat transfer pipe 33 is supplied into the pipe. Further, the gas-liquid separator 41 is provided between the heat transfer pipe 33 and the steam heating heat transfer pipe 221, and the gas-liquid separator 41 is connected with the heat transfer pipe 33 and the steam heating heat transfer pipe 221. Furthermore, the gas liquid separator 41 has substantially the same configuration as that of the first embodiment, and the drying steam flows from the heat transfer pipe 33 into the separator. The gas-liquid separator 41 separates the drying steam which flows from the heat transfer pipe 33 into a liquid phase and a gas phase so as to supply the gas-phase drying steam to the steam heating heat transfer pipe 221 and to discharge the liquid-phase drying steam as condensed water. Accordingly, when the drying steam is supplied from the steam compressor 135, the supplied drying steam flows into the heat transfer pipe 33. When the drying steam is 29 supplied into the heat transfer pipe 33, the pipe heats the brown coal by using the latent 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 brown coal in the drying region 12b of the drying chamber 12. Subsequently, the drying steam which circulates in the heat transfer pipe 33 flows into the steam heating heat transfer pipe 221. When the drying steam is supplied into the steam heating heat transfer pipe 221, the pipe heats the steam which is discharged from the steam.discharge port 35 by using the latent heat of the drying steam. Subsequently, the drying steam which is used to heat the discharged steam is discharged to the outside of the drying chamber 12. As described above, according to the configuration of the fourth embodiment, the steam which is discharged from the steam discharge port 35 may be heated by the drying steam of which the ratio of the gas-phase non-condensable gas is larger than that of the heat transfer pipe 33. Meanwhile, the brown coal which flows in the drying region 12b may be heated and dried by the drying steam of which the ratio of the gas-phase non-condensable gas is smaller than that of the drying steam which is used to heat the steam discharged from the steam discharge port 35. Accordingly, since the drying steam of which the ratio of the non-condensable gas is large may be used to heat the steam, the latent heat of the steam may be efficiently collected. [Fifth embodiment] Next, a fluid bed drying apparatus 230 according to a fifth embodiment will be described by referring to FIG. 7. FIG. 7 is a schematic configuration diagram roughly illustrating the fluid bed drying apparatus according to 30 the fifth embodiment. Furthermore, even in the fifth 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 steam of which the ratio of the gas-phase non condensable gas is large is used to preheat the brown coal, but in the fluid bed drying apparatus 230 according to the fifth embodiment, the drying steam of which the ratio of the gas-phase non-condensable gas is large is used to retain the heat of the heat retaining subject. Hereinafter, the fluid bed drying apparatus 230 according to the fifth embodiment will be described. As illustrated in FIG. 7, in the fluid bed drying apparatus 230 of the fifth embodiment, the inside of the drying chamber 12 of the drying furnace 5 becomes the drying region 12b. For this reason, the brown coal input port 31 is formed at the upper portion of one end side (the left side of the drawing) of the drying region 12b of the drying chamber 12. The heat transfer pipe 33 is formed as a panel structure, and is provided inside the brown coal which flows in the drying region 12b. The heat transfer pipe 33 is connected with the outflow 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. The flow direction of the brown coal of the heat transfer pipe 33 is directed from the downstream side toward the upstream side, and the pipe circulates the drying steam. Further, a pipe 232 which connects the steam discharge port 35 and the steam compressor.135 to each other is 31 provided with a steam trace pipe (heat retaining heat transfer member) 231. The steam trace pipe 231 is wound on the outer periphery of the pipe 232 in a spiral shape, and may retain the heat of the pipe 232. That is, in the fifth embodiment, the heat retaining subject becomes the pipe 232. The steam trace pipe 231 is connected with the outflow side of the heat transfer pipe 33, and the drying steam which circulates in the heat transfer pipe 33 is supplied into the steam trace pipe. Further, the gas-liquid separator 41 is provided between the heat transfer pipe 33 and the steam trace pipe 231, and the gas-liquid separator 41 is connected with the heat transfer pipe 33 and the steam trace pipe 231. Furthermore, even in the fifth embodiment, since the gas liquid separator 41 has substantially the same configuration as those of the first and second embodiments, the description thereof will not be repeated. Accordingly, when the drying steam is supplied from the steam compressor 135, the supplied drying steam flows into the heat transfer pipe 33. When the drying steam is supplied into the heat transfer pipe 33, the pipe heats the brown coal by using the latent 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 brown coal in the drying region 12b of the drying chamber 12. Subsequently, the drying steam which circulates in the heat transfer pipe 33 flows into the steam trace pipe 231. When the drying steam is supplied into the steam trace pipe 231, the pipe retains the heat of the pipe 232 by using the latent heat of the drying steam. Subsequently, the drying steam which is used to retain the heat is discharged to the outside of the fluid bed drying apparatus 230. As described above, according to the configuration of 32 the fifth embodiment, the heat of the pipe 232 which becomes the heat retaining subject may be retained by the drying steam of which the ratio of the gas-phase non condensable gas is larger than that of the heat transfer pipe 33. Meanwhile, the brown coal which flows in the drying region 12b may be heated and dried by the drying steam of which the-ratio of the gas-phase non-condensable gas is smaller than that of the drying steam which is used to retain the heat of the pipe 232 as the heat retaining subject. Accordingly, since the drying steam of which the ratio of the non-condensable gas is large may be used to retain the heat of the pipe 232, the latent heat of the steam may be efficiently collected. [Sixth embodiment] Next, a fluid bed drying apparatus 240 according a sixth embodiment will be described by referring to FIG. 8. .FrG- 8 is a schematic configuration diagram roughly illustrating the fluid bed drying apparatus according to the sixth embodiment. Furthermore, even in the sixth 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 230 according to the fifth embodiment, the heat retaining subject is the pipe 232, but in the fluid bed drying apparatus 240 according to the sixth embodiment, the heat retaining subject becomes the drying furnace 5. Hereinafter, the fluid bed drying apparatus 240 according to the sixth embodiment will be described. As illustrated in FIG. 8, in the fluid bed drying apparatus 240 of the sixth embodiment, the wall surface of the drying furnace 5 is provided with a steam trace pipe (heat retaining heat transfer member) 241. The steam trace 33 pipe 241 is provided along the wall surface of the drying furnace 5 so as to surround the drying furnace. That is, in the sixth embodiment, the heat retaining subject becomes the drying furnace 5. Furthermore, FIG. 8 illustrates a configuration in which a part of the wall surface of the drying furnace 5 is provided with the steam trace pipe 241. The steam trace pipe 241 is connected with the outflow side of the heat transfer pipe 33, and the drying steam which circulates in the heat transfer pipe 33 is supplied into the pipe. Further, the gas-liquid separator 41 is provided between the heat transfer pipe 33 and the steam trace pipe 241, and the gas-liquid separator 41 is connected with the heat transfer pipe 33 and the steam trace pipe 241. Furthermore, even in the sixth embodiment, since the gas liquid separator 41 has substantially the same configuration as that of the first and second embodiments, the description thereof will not be repeated. Accordingly, when the drying steam is supplied from the steam compressor 135, the supplied drying steam flows into the heat transfer pipe 33. When the drying steam is supplied into the heat transfer pipe 33, the pipe heats the brown coal by using the latent 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 brown coal in the drying region 12b of the drying chamber 12. Subsequently, the drying steam which circulates in the heat transfer pipe 33 flows into the steam trace pipe 241. When the drying steam is supplied into the steam trace pipe 241, the pipe retains the heat of the drying furnace 5 by using the latent heat of the drying steam. Subsequently, the drying steam which is used to retain the heat is discharged to the outside of the fluid bed drying apparatus 240.

34 As described above, according to the configuration of the sixth embodiment, the heat of the drying furnace 5 which becomes the heat retaining subject may be retained by the drying steam of which the ratio of the gas-phase non condensable gas is larger than that of the heat transfer pipe 33. Meanwhile, the brown coal which flows in the drying region 12b may be heated and dried by the drying steam of which the ratio of the gas-phase non-condensable gas is smaller than that of the drying steam used to retain the heat of the drying furnace 5 as the heat retaining subject. Accordingly, since the drying steam of which the ratio of the non-condensable gas is large may be used to retain the heat of the drying furnace 5, the latent heat of the steam may be efficiently collected. Furthermore, in the fifth embodiment and the sixth embodiment, the wall surface of the pipe 232 or the drying furnace 5 is employed as the heat retaining subject, but the invention is not limited to the configuration. That is, a configuration may be employed in which the fifth embodiment and the sixth embodiment are combined with each other. Further, as the heat retaining subject, a member other than the pipe 232 or the drying furnace 5 may be employed. Further, in the third to sixth embodiments, the drying chamber 12 includes only the drying region 12b, but as in the first and second embodiments, the drying chamber 12 may be divided into the preheating region 12a and the drying region 12b. According to the embodiment of the fluid bed drying apparatus, the upstream-wet fuel in the flow direction may be preheated by the steam of which the ratio of the gas phase non-condensable gas is large and the downstream wet fuel in the flow direction may be heated by the steam of 35 which the ratio of the gas-phase non-condensable gas is small- At this time, since the temperature of the upstream wet fuel is lower than the temperature of the downstream wet fuel, even when the steam of which the ratio of the gas-phase non-condensable gas is large is used, the temperature difference between the temperature of the wet fuel and the temperature of the steam may be appropriately ensured. Accordingly, since the wet fuel may be appropriately preheated by the wet fuel of which the ratio of the gas-phase non-condensable gas is large, the steam may be effectively utilized and hence the latent heat of the steam may be efficiently collected According to the embodiment of the fluid bed drying apparatus, the upstream heat transfer member is provided at the preheating region of which the temperature of the wet fuel is low inside the drying furnace, the downstream heat transfer member is provided at the drying region of which the temperature of the wet fuel is high inside the drying furnace, and the steam supplied from the compressor may be circulated in the upstream heat transfer member after being circulated in the downstream heat transfer member. For this reason, the wet fuel of the preheating region may be preheated by the steam of which the ratio of the gas-phase non-condensable gas is large. According to the embodiment of the fluid bed drying apparatus, 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- 36 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 the liquid membrane from being formed inside the upstream heat transfer member and hence to improve the heat transfer rate. According to the embodiment of the fluid bed drying apparatus, since the heat transfer member may be provided from the preheating region of which the temperature of the wet fuel is low inside the drying furnace to the drying region of which the temperature of the wet fuel is high inside the drying furnace, the steam which changes from the high-quality state to the low-quality state may be circulated toward the preheating region. For this reason, the wet fuel of the preheating region may be preheated by the low-quality steam. According to the embodiment of the fluid bed drying apparatus, the wet fuel inside the fuel supply device may be preheated by the low-quality steam of which the ratio of the gas-phase non-condensable gas is large. For this reason, since the preheated wet fuel may be supplied to the fluid bed drying apparatus, it is possible to suppress the re-condensation of the steam at the supply side (that is, the upstream side in the flow direction of the wet fuel) of the fluid bed drying apparatus. Accordingly, it is possible to suppress a poor fluidization by suppressing the aggregation of the wet fuel caused by the condensed water. According to the embodiment of the fluid bed drying apparatus, the steam which is discharged from the drying furnace may be heated by the low-quality steam of which the ratio of the gas-phase non-condensable gas is large. For this reason, since the preheated steam may be compressed by 37 the compressor, the temperature of the recompressed steam may be appropriately increased. Further, since the steam discharged from the drying furnace is heated, it is possible to prevent the condensation of the steam inside the pipe connecting the drying furnace and the compressor to each other and hence to prevent the adhering of scattered particles inside the pipe, the blocking of the pipe, and the mixing of water droplets into the compressor. According to the embodiment of the fluid bed drying apparatus, since the heat of the heat retaining subject may be retained by the low-quality steam of which the ratio of the gas-phase non-condensable gas is large, it is possible to suppress the radiation of heat from the heat retaining subject. Furthermore, as the heat retaining subject, the pipe connecting the drying furnace to the compressor or the wall surface of the drying furnace is exemplified. According to the embodiment of the gasification combined power generating facility, since it is possible to improve the efficiency of collecting the latent heat of the steam in the fluid bed drying apparatus, the latent heat may be effectively utilized and hence the power generation efficiency of the generator connected to the steam turbine may be improved. According to the embodiment of the drying method, the upstream wet fuel in the flow direction may be preheated 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. Further, the downstream wet fuel in the flow direction 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. At this time, since the temperature of the upstream wet fuel is lower than the temperature of the 38 downstream wet fuel, even when the low-quality steam of which the ratio of the gas-phase non-condensable gas is large is used, the temperature difference between the temperature of the wet fuel and the temperature of the steam may be appropriately ensured. Accordingly, since the wet fuel may be appropriately preheated by the low-quality steam, the low-quality steam may be effectively utilized and hence the latent heat of the low-quality steam may be efficiently collected. Further, since the liquid-phase steam circulating in the downstream heat transfer member is discharged as the condensed water in the gas-liquid separating process, it is possible to increase the ratio of the gas-phase component of the steam supplied to the upstream heat transfer member. Accordingly, since it is possible to suppress the liquid-phase steam from flowing into the upstream heat transfer member, it is possible to suppress the liquid membrane from being formed inside the upstream heat transfer member and hence to improve the heat transfer rate. According to the fluid bed drying apparatus of the embodiments, the gasification combined power generating facility, and the drying method of the invention, since the low-quality steam of which the ratio of the gas-phase non condensable gas is large may be effectively utilized, the latent heat of the steam may be efficiently collected.

Claims (13)

1. A fluid bed drying apparatus comprising: a drying furnace for fluidizing a wet fuel by fluidizing steam so as to form a fluid bed therein; a heat transfer member provided inside the drying furnace for heating the wet fuel; and a compressor for compressing steam discharged from the drying furnace so as to supply the compressed steam to the heat transfer member, wherein the heat transfer member is configured to circulate the steam supplied from the compressor from the downstream side toward the upstream side in the flow direction of the wet fuel.

2. The fluid bed drying apparatus according to claim 1, wherein a ratio of a gas-phase non-condensable gas of the steam circulating at the upstream side in the flow direction of the beat transfer member is larger than that of the steam circulating at the downstream side in the flow direction of the heat transfer member.

3. The fluid bed drying apparatus according to claim 1 or 2, wherein the drying furnace includes: a preheating region provided at the upstream side in the flow direction of the wet fuel; and a drying region provided at the downstream side of the preheating region, the temperature of the wet fuel inside the drying furnace at the preheating region being lower than that of the drying furnace at the drying region, and wherein the heat transfer member includes: an upstream heat transfer member provided in the 40 preheating region and a downstream heat transfer member provided in the drying region, so that the steam supplied from the compressor circulates in the downstream heat transfer member and then circulates in the upstream heat transfer member.

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

5. The fluid bed drying apparatus according to claim 1 or 2, wherein the drying furnace includes: a preheating region provided at the upstream side in the flow direction of the wet fuel; and a drying region provided at the downstream side of the preheating region, the temperature of the wet fuel inside the drying furnace at the preheating region being lower than that of the drying furnace at the drying region, and wherein the beat transfer member is provided from the preheating region to the drying region.

6. The fluid bed drying apparatus according to any one of claims 1 to 5, further comprising a preheating heat transfer member provided inside a fuel supply device supplying the wet fuel for preheating the wet fuel, 41 wherein the preheating heat transfer member is provided so that the steam supplied from the compressor circulates after circulating in the heat transfer member.

7. The fluid bed drying apparatus according to any one of claims 1 to 6, further comprising a steam heating heat transfer member provided inside the drying furnace for heating the steam discharged from the drying furnace wherein the'steam heating heat transfer member is provided so that the steam supplied from the compressor circulates after circulating in the heat transfer member.

8. The fluid bed drying apparatus according to any one of claims 1 to 7, further comprising a heat retaining heat transfer member provided in a heat retaining subject, wherein the heat retaining heat transfer member is provided so that the steam supplied from the compressor circulates after circulating in the heat transfer member.

9. A gasification combined power generating facility comprising: the fluid bed drying apparatus according to any one of claims 1 to 8; 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 exhaust gas is introduced from the gas turbine; and 42 a generator connected to the gas turbine and the steam turbine.

10. 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 heat transfer member includes: an upstream heat transfer member provided at the upstream side in the flow direction of the wet fuel; and a downstream heat transfer member provided at the downstream side of the upstream heat transfer member, and wherein the drying method comprises: discharging steam produced when drying the wet fuel from the drying furnace; compressing the steam discharged in the discharging of the steam; supplying the steam compressed in the compressing of the steam to the downstream heat transfer member; and separating the steam flowing from the downstream heat transfer member in the supplying of the downstream steam into a gas and a liquid so as to discharge the liquid-phase steam as condensed water and to supply the gas-phase steam to the upstream heat transfer member.

11. 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.

12. 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. 43

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