JP5777402B2 - Fluidized bed dryer - Google Patents

Description

  The present invention relates to a fluidized bed drying apparatus that dries wet fuel such as lignite while flowing.

  2. Description of the Related Art Conventionally, there is known a control device capable of controlling a coal drying / classifying device that blows hot air from below the coal supplied to the fluidized drying chamber to dry the coal while flowing (see, for example, Patent Document 1). . The drying / classification device controlled by this control device has a fluidized drying chamber and a classification chamber, and in the fluidized drying chamber, the coal is dried, and in the classification chamber, the coal is classified into fine coal and coarse coal. ing.

JP 7-11270 A

  However, in the conventional drying / classification apparatus, the coal in the fluidized drying chamber is dried while flowing from the upstream side to the downstream side in the flow direction of the coal. At this time, since the coal supplied into the fluidized drying chamber is likely to diffuse in the flow direction, there is a possibility that a part of the coal flows into the classification chamber on the downstream side in the flow direction while remaining in an undried state. For this reason, in the conventional drying / classification apparatus, undried coal and dry coal are mixed in the classification chamber, and it is difficult to sufficiently dry the coal.

  Therefore, an object of the present invention is to provide a fluidized bed drying apparatus capable of sufficiently drying wet fuel.

  The fluidized bed drying apparatus of the present invention includes a drying furnace that forms a fluidized bed inside by flowing wet fuel with a fluidized gas, and the drying furnace includes a first drying chamber that performs initial drying of the wet fuel, A second drying chamber that performs the latter drying of the wet fuel supplied from the first drying chamber, and in the first drying chamber, the supplied wet fuel is dried while being in a completely mixed flow, so that the second drying is performed. The chamber is characterized in that the wet fuel supplied from the first drying chamber is dried while flowing along the flow direction of the wet fuel.

  According to this configuration, the first drying chamber can be dried so that the moisture content of the supplied wet fuel becomes uniform by the complete mixing flow, and the homogenized wet fuel is fed to the second drying chamber. Can be supplied. In the second drying chamber, the supplied wet fuel can be dried along the flow direction by the flow along the flow direction. Thereby, since the wet fuel can be dried in the first drying chamber and the second drying chamber, the wet fuel can be sufficiently dried.

  In this case, it is preferable that the flow along the flow direction of the wet fuel is an extrusion flow.

  According to this configuration, in the second drying chamber, the supplied wet fuel can be dried by the extrusion flow without being diffused in the flow direction. This makes it difficult for the wet fuel in the undried state to flow beyond the wet fuel in the dry state, so that the discharge of the wet fuel in the undried state can be suppressed, and the wet fuel can be sufficiently dried. It becomes.

  In this case, it is preferable that the second drying chamber has a plurality of drying compartments divided in the flow direction of the wet fuel.

  According to this configuration, the wet fuel supplied from the first drying chamber passes through all the drying compartments of the second drying chamber and is dried. Thereby, since the wet fuel can be dried in a plurality of drying compartments, the wet fuel can be sufficiently dried over time.

  In this case, the wet fuel is caused to flow out from the first drying chamber, the recirculation line through which the drained wet fuel flows back into the first drying chamber, and the wet fuel that is interposed in the recirculation line and passes through the recirculation line. It is preferable to further include foreign matter removing means for removing the contained foreign matter.

  According to this configuration, by providing the recirculation line, the wet fuel being dried can be discharged from the first drying chamber, and the discharged wet fuel can be supplied again to the first drying chamber. For this reason, since the wet fuel during drying and the wet fuel before drying are supplied to the first drying chamber, the drying of the wet fuel is promoted as much as the wet fuel during drying is supplied. it can. At this time, since the foreign matter removing means is provided in the recirculation line, the foreign matter contained in the wet fuel flowing through the recirculation line can be removed, so that the recirculation line can be prevented from being blocked by the foreign matter. In addition, as a foreign material, there exist the metal, wood, or the solid substance of the condensed wet fuel etc. which were mixed in the wet fuel.

  In this case, the recirculation line has a fuel discharge port through which wet fuel flows out from the first drying chamber, and the fuel discharge port sandwiches the boundary portion between the first drying chamber and the second drying chamber, It is preferable that it is connected to the bottom face on the side of 1 drying chamber.

  According to this configuration, the wet fuel before flowing into the second drying chamber, that is, the wet fuel after the initial drying can be recirculated, so that the drying of the wet fuel in the first drying chamber can be further promoted. .

  In this case, the second drying chamber is preferably provided with a damming portion on the bottom surface on the second drying chamber side with the boundary portion between the first drying chamber and the second drying chamber interposed therebetween.

  According to this configuration, a portion of the wet fuel supplied from the first drying chamber to the second drying chamber can be blocked by the blocking portion, and the partially blocked wet fuel is discharged from the recirculation line. Can flow into the port. Thereby, the wet fuel which flows into a recirculation line can be increased, and drying of the wet fuel in a 1st drying chamber can further be promoted.

  In this case, it is preferable that the recirculation line has a resupply port through which the wet fuel that has flowed out from the first drying chamber flows, and the resupply port is connected to the first drying chamber.

  According to this configuration, the wet fuel flowing through the recirculation line can be directly supplied to the first drying chamber.

  In this case, the recirculation line has a resupply port through which wet fuel that has flowed out from the first drying chamber flows, and the resupply port is connected to a fuel bunker that stores wet fuel to be supplied toward the first drying chamber. It is preferable that

  According to this configuration, the wet fuel flowing through the recirculation line can be indirectly supplied to the first drying chamber via the fuel bunker.

  In this case, the floor area ratio of the first drying chamber and the second drying chamber is preferably “first drying chamber: second drying chamber = 30-50%: 70-50%”.

  According to this configuration, the wet fuel flowing in the first drying chamber and the second drying chamber can be dried according to the floor area ratio. Thereby, the wet fuel can be suitably dried in the first drying chamber and the second drying chamber.

  According to the fluidized bed drying apparatus of the present invention, since the supplied wet fuel can be dried in the second drying chamber without diffusing along the flow direction, the wet fuel in an undried state is in a dry state. It becomes difficult to flow beyond the wet fuel, and the wet fuel can be suitably dried while suppressing the discharge of the wet fuel in an undried state.

FIG. 1 is a schematic configuration diagram of a coal gasification combined power generation facility to which a fluidized bed drying apparatus according to a first embodiment is applied. FIG. 2 is a schematic configuration diagram schematically illustrating the fluidized bed drying apparatus according to the first embodiment. FIG. 3 is a schematic configuration diagram schematically illustrating a fluidized bed drying apparatus according to the first modification. FIG. 4 is a schematic configuration diagram schematically illustrating the fluidized bed drying apparatus according to the second embodiment.

  Hereinafter, a fluidized bed drying apparatus according to the present invention will be described with reference to the accompanying drawings. The present invention is not limited to the following examples. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

  FIG. 1 is a schematic configuration diagram of a coal gasification combined power generation facility to which a fluidized bed drying apparatus according to a first embodiment is applied. An integrated coal gasification combined cycle (IGCC) 100 to which the fluidized bed drying apparatus 1 of Example 1 is applied employs an air combustion system that generates coal gas in a gasification furnace using air as an oxidant. The coal gas refined by the gas purifier is supplied as fuel gas to the gas turbine equipment for power generation. That is, the combined coal gasification combined power generation facility 100 according to the first embodiment is an air combustion type (air blowing) power generation facility. In this case, lignite is used as a wet raw material supplied to the gasifier.

  In Example 1, lignite was applied as a wet raw material, but low-grade coal including subbituminous coal or the like, peat such as sludge, etc. may be applied as long as the moisture content is high. Even charcoal is applicable. In addition, the wet raw material is not limited to coal such as lignite, but may be biomass used as organic resources derived from renewable organisms. For example, thinned wood, waste wood, driftwood, grass, waste, It is also possible to use sludge, tires, and recycled fuel (pellets and chips) made from these raw materials.

  In Example 1, as shown in FIG. 1, the coal gasification combined power generation facility 100 includes a coal supply device 111, a fluidized bed drying device 1, a pulverized coal machine (mill) 113, a coal gasification furnace 114, and a char recovery device 115. , Gas refiner 116, gas turbine facility 117, steam turbine facility 118, generator 119, and exhaust heat recovery steam generator (HRSG) 120.

  The coal feeder 111 includes a raw coal bunker (fuel bunker) 121, a coal feeder 122, and a crusher 123. The raw coal bunker 121 can store lignite, and drops a predetermined amount of lignite into the coal feeder 122. The coal feeder 122 transports the brown coal dropped from the raw coal bunker 121 by a conveyor or the like and drops it on the crusher 123. The crusher 123 finely pulverizes the dropped lignite into fine particles.

  The fluidized bed drying apparatus 1 supplies drying steam such as superheated steam to the lignite charged by the coal feeder 111, thereby heating and drying the lignite while flowing, thereby removing moisture contained in the lignite. It is. The fluidized bed drying apparatus 1 is provided with a cooler 131 that cools dried lignite (dry coal) taken out from the lower portion, and the dried and cooled dried coal is stored in the dried coal bunker 132. Further, the fluidized bed drying apparatus 1 is provided with a dry coal cyclone 133 and a dry coal electrostatic precipitator 134 for separating dry coal particles from steam taken out from above, and the dry coal particles separated from the steam are dried coal bunker. 132 is stored. The steam from which the dry coal is separated by the dry coal electrostatic precipitator 134 is compressed by the steam compressor 135 and then supplied to the fluidized bed drying apparatus 1 as drying steam.

  The pulverized coal machine 113 is a coal pulverizer, and pulverized coal (dried coal) dried by the fluidized bed drying apparatus 1 is pulverized into fine particles to produce pulverized coal. In other words, when the dry coal stored in the dry coal bunker 132 is dropped by the coal feeder 136, the pulverized coal machine 113 converts the dry coal into pulverized coal having a predetermined particle size or less. The pulverized coal after being pulverized by the pulverized coal machine 113 is separated from the conveying gas by the pulverized coal bag filters 137a and 137b and stored in the pulverized coal supply hoppers 138a and 138b.

  The coal gasifier 114 is supplied with pulverized coal processed by the pulverized coal machine 113 and supplied with char (unburned coal) recovered by the char recovery device 115.

  The coal gasification furnace 114 is connected to a compressed air supply line 141 from a gas turbine facility 117 (compressor 161), and can supply compressed air compressed by the gas turbine facility 117. The air separation device 142 separates and generates nitrogen and oxygen from air in the atmosphere. A first nitrogen supply line 143 is connected to the coal gasifier 114, and a pulverized coal supply hopper is connected to the first nitrogen supply line 143. Charging lines 144a and 144b from 138a and 138b are connected. The second nitrogen supply line 145 is also connected to the coal gasifier 114, and the char return line 146 from the char recovery device 115 is connected to the second nitrogen supply line 145. Further, the oxygen supply line 147 is connected to the compressed air supply line 141. In this case, nitrogen is used as a carrier gas for coal and char, and oxygen is used as an oxidant.

  The coal gasification furnace 114 is, for example, a spouted bed type gasification furnace, which combusts and gasifies coal, char, air (oxygen) supplied therein, or water vapor as a gasifying agent, and produces carbon dioxide. A combustible gas (product gas, coal gas) containing carbon as a main component is generated, and a gasification reaction takes place using this combustible gas as a gasifying agent. Note that the coal gasification furnace 114 is provided with a foreign matter removing device 148 that removes foreign matter mixed with pulverized coal. In this case, the coal gasification furnace 114 is not limited to the spouted bed gasification furnace, and may be a fluidized bed gasification furnace or a fixed bed gasification furnace. The coal gasification furnace 114 is provided with a gas generation line 149 for combustible gas toward the char recovery device 115, and can discharge combustible gas containing char. In this case, by providing a gas cooler in the gas generation line 149, the combustible gas may be cooled to a predetermined temperature and then supplied to the char recovery device 115.

  The char recovery device 115 includes a dust collector 151 and a supply hopper 152. In this case, the dust collector 151 is constituted by one or a plurality of bag filters or cyclones, and can separate the char contained in the combustible gas generated in the coal gasification furnace 114. The combustible gas from which the char has been separated is sent to the gas purifier 116 through the gas discharge line 153. The supply hopper 152 stores the char separated from the combustible gas by the dust collector 151. A bin may be disposed between the dust collector 151 and the supply hopper 152, and a plurality of supply hoppers 152 may be connected to the bin. A 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 by removing impurities such as sulfur compounds and nitrogen compounds from the combustible gas from which the char has been separated by the char recovery device 115. The gas purifier 116 purifies the combustible gas to produce fuel gas, and supplies it to the gas turbine equipment 117. In this gas purifier 116, since the combustible gas from which the char is separated still contains sulfur (H ₂ S), the sulfur is finally removed by removing it with the amine absorbent. Is recovered as gypsum and used effectively.

  The gas turbine equipment 117 includes a compressor 161, a combustor 162, and a turbine 163, and the compressor 161 and the turbine 163 are connected by a rotating shaft 164. The combustor 162 has a compressed air supply line 165 connected from the compressor 161, a fuel gas supply line 166 connected from the gas purification device 116, and a combustion gas supply line 167 connected to the turbine 163. Further, the gas turbine equipment 117 is provided with a compressed air supply line 141 extending from the compressor 161 to the coal gasification furnace 114, and a booster 168 is interposed in the compressed air supply line 141. Therefore, in the combustor 162, the compressed air supplied from the compressor 161 and the fuel gas supplied from the gas purifier 116 are mixed and burned, and the rotating shaft 164 is rotated by the generated combustion gas in the turbine 163. By doing so, the generator 119 can be driven.

  The steam turbine equipment 118 has a turbine 169 connected to the rotating shaft 164 in the gas turbine equipment 117, and the generator 119 is connected to the base end portion of the rotating shaft 164. The exhaust heat recovery boiler 120 is provided in the exhaust gas line 170 from the gas turbine equipment 117 (the turbine 163), and generates steam by exchanging heat between air and high-temperature exhaust gas. Therefore, the exhaust heat recovery boiler 120 is provided with a steam supply line 171 and a steam recovery line 172 between the turbine 169 of the steam turbine equipment 118, and a condenser 173 is provided in the steam recovery line 172. Yes. Therefore, in the steam turbine equipment 118, the turbine 169 is driven by the steam supplied from the exhaust heat recovery boiler 120, and the generator 119 can be driven by rotating the rotating shaft 164.

  The exhaust gas from which heat has been recovered by the exhaust heat recovery boiler 120 is removed of harmful substances by the gas purification device 174, and the purified exhaust gas is discharged from the chimney 175 to the atmosphere.

  Here, the operation of the coal gasification combined cycle facility 100 of the first embodiment will be described.

  In the combined coal gasification combined power generation facility 100 of the first embodiment, raw coal (brown coal) is stored in the raw coal bunker 121 by the coal feeder 111, and the lignite in the raw coal bunker 121 is crushed by the coal feeder 122. It is dropped to 123, where it is crushed to a predetermined size. The crushed lignite is heated and dried by the fluidized bed drying apparatus 1, cooled by the cooler 131, and stored in the dry coal bunker 132. Further, the steam taken out from the upper part of the fluidized bed drying device 1 is separated into dry coal particles by the dry coal cyclone 133 and the dry coal electric dust collector 134 and compressed by the steam compressor 135, and then the fluidized bed drying device 1. Returned as drying steam. On the other hand, dry coal particles separated from the steam are stored in the dry coal bunker 132.

  The dry coal stored in the dry coal bunker 132 is supplied to the pulverized coal machine 113 by the coal feeder 136, where it is pulverized into fine particles to produce pulverized coal, and the pulverized coal bag filters 137a and 137b are used. And stored in pulverized coal supply hoppers 138a and 138b. The pulverized coal stored in the pulverized coal supply hoppers 138 a and 138 b is supplied to the coal gasification furnace 114 through the first nitrogen supply line 143 by nitrogen supplied from the air separation device 142. Further, the char recovered by the char recovery device 115 described later is supplied to the coal gasifier 114 through the second nitrogen supply line 145 by nitrogen supplied from the air separation device 142. Further, compressed air extracted from a gas turbine facility 117 described later is boosted by a booster 168 and then supplied to the coal gasifier 114 through the compressed air supply line 141 together with oxygen supplied from the air separation device 142.

  In the coal gasification furnace 114, the supplied pulverized coal and char are combusted by compressed air (oxygen), and the pulverized coal and char are gasified, so that combustible gas (coal gas) mainly containing carbon dioxide is obtained. Can be generated. This combustible gas is discharged from the coal gasifier 114 through the gas generation line 149 and sent to the char recovery device 115.

  In the char recovery device 115, the combustible gas is first supplied to the dust collector 151, and the dust collector 151 separates the char contained in the combustible gas. The combustible gas from which the char has been separated is sent to the gas purifier 116 through the gas discharge line 153. On the other hand, the fine char separated from the combustible gas is deposited on the supply hopper 152, returned to the coal gasifier 114 through the char return line 146, and recycled.

  The combustible gas from which the char has been separated by the char recovery device 115 is gas purified by removing impurities such as sulfur compounds and nitrogen compounds by the gas purification device 116 to produce fuel gas. In the gas turbine equipment 117, when the compressor 161 generates compressed air and supplies the compressed air to the combustor 162, the combustor 162 is supplied from the compressed air supplied from the compressor 161 and the gas purifier 116. Combustion gas is generated by mixing with fuel gas and combusting, and the turbine 163 is driven by this combustion gas, so that the generator 119 is driven via the rotating shaft 164 to generate power.

  The exhaust gas discharged from the turbine 163 in the gas turbine facility 117 generates steam by exchanging heat with air in the exhaust heat recovery boiler 120, and supplies the generated steam to the steam turbine facility 118. . In the steam turbine equipment 118, the turbine 169 is driven by the steam supplied from the exhaust heat recovery boiler 120, whereby the generator 119 can be driven via the rotating shaft 164 to generate power.

  Thereafter, in the gas purification device 174, harmful substances in the exhaust gas discharged from the exhaust heat recovery boiler 120 are removed, and the purified exhaust gas is released from the chimney 175 to the atmosphere.

  Hereinafter, the fluidized bed drying apparatus 1 in the coal gasification combined power generation facility 100 described above will be described in detail. FIG. 2 is a schematic configuration diagram schematically illustrating the fluidized bed drying apparatus according to the first embodiment. The fluidized-bed drying apparatus 1 of Example 1 heat-drys the lignite which is coal with a high water content, making it flow with a fluidization gas.

  The fluidized bed drying apparatus 1 includes a drying furnace 5 in which lignite is supplied and a gas dispersion plate 6 provided inside the drying furnace 5. The drying furnace 5 is formed in a rectangular box shape. The lignite supplied to the drying furnace 5 flows by the fluidizing gas, thereby forming the fluidized bed 3 in the drying furnace 5. The flow direction of the fluidized bed 3 formed in the drying furnace 5 is the longitudinal direction of the drying furnace 5 (the left-right direction in FIG. 2). The gas distribution plate 6 divides the space inside the drying furnace 5 into a chamber chamber 11 located on the lower side in the vertical direction (lower side in the drawing) and a drying chamber 12 located on the upper side in the vertical direction (upper side in the drawing). Yes. A number of through holes are formed in the gas dispersion plate 6, and a fluidizing gas such as steam is introduced into the chamber chamber 11.

  The drying chamber 12 formed in the drying furnace 5 includes a first drying chamber 21 provided on the upstream side in the flow direction and a second drying chamber 22 provided on the downstream side in the flow direction. The chamber 21 and the second drying chamber 22 communicate with each other. The first drying chamber 21 is a complete mixing region where initial drying is performed, and the second drying chamber 22 is an extrusion region (plug flow region) where late drying is performed.

  The 1st drying chamber 21 is comprised so that the supplied lignite may become a completely mixed flow in the chamber | room. The complete mixing flow is a flow in which the fluidized bed 3 formed in the first drying chamber 21 is mixed so that the moisture content of the lignite is uniform. For this reason, in the 1st drying chamber 21, the back mixing which mixes while flowing back in the flow direction is permitted. The first drying chamber 21 is provided with a supply port 31 for supplying lignite and a heat transfer tube 33 for heating the lignite.

  The supply port 31 is connected to the side wall of the first drying chamber 21 on the upstream side in the flow direction of the lignite, and serves as a supply port for supplying the lignite to the first drying chamber 21. The crusher 123 described above is connected to the supply port 31, and the pulverized lignite is supplied to the first drying chamber 21.

  The heat transfer tube 33 is provided inside the fluidized bed 3. The heat transfer pipe 33 is supplied with drying steam therein to remove moisture in the brown coal of the fluidized bed 3. Therefore, when the drying steam is supplied to the heat transfer pipe 33, the heat transfer pipe 33 uses the latent heat of the drying steam to dry the lignite in the first drying chamber 21. Thereafter, the drying steam used for drying is discharged outside the first drying chamber 21.

  Therefore, when lignite is supplied from the supply port 31, the supplied lignite flows by the fluidized gas supplied via the gas dispersion plate 6, thereby forming the fluidized bed 3. The lignite that has become the fluidized bed 3 is dried by being heated by the fluidizing gas and the heat transfer tube 33.

  Thereby, the brown coal which forms the fluidized bed 3 of the 1st drying chamber 21 can be made into a complete mixed flow. Therefore, in the fluidized bed 3 in the 1st drying chamber 21, the lignite which became the complete mixed flow can be dried, homogenizing. At this time, the generated steam generated by drying the lignite is discharged toward a dry coal cyclone 133 described above from a steam discharge port 42 provided in the second drying chamber 22 described later. The brown coal initially dried in the first drying chamber 21 is supplied to the second drying chamber 22. In the first drying chamber 21, for example, lignite having a moisture content of about 60% is initially dried until the moisture content becomes about 40%.

  The 2nd drying chamber 22 is comprised so that the supplied lignite may flow along a flow direction in the room | chamber interior, It is comprised especially so that it may become an extrusion flow. An extrusion flow is a flow which extrudes lignite in the flow direction so that the lignite does not diffuse in the flow direction in the fluidized bed 3 formed in the second drying chamber 22. The second drying chamber 22 is provided with a discharge port 41 through which brown coal is discharged, a steam discharge port 42 through which generated steam is discharged, and a plurality of partition plates 43.

  The discharge port 41 is formed at the bottom of the second drying chamber 22 on the downstream side in the flow direction of the lignite, and serves as an outlet for discharging the lignite from the second drying chamber 22. In the discharge port 41, the lignite that has been dried in the second drying chamber 22 is discharged as dry coal, and the discharged dry coal is supplied to the cooler 131 described above.

  The steam discharge port 42 is formed on the upper surface of the second drying chamber 22 on the downstream side in the flow direction of the lignite, and discharges generated steam generated from the first drying chamber 21 and the second drying chamber 22 when the lignite is dried. It is a discharge port for. The generated steam discharged from the steam discharge port 42 is supplied toward the dry coal cyclone 133.

  The some partition plate 43 is arrange | positioned at predetermined intervals in the flow direction of lignite. Each partition plate 43 is provided such that its plate surface is orthogonal to the flow direction. Therefore, the plurality of partition plates 43 divide the second drying chamber 22 into a plurality of drying compartments 45, and the plurality of drying compartments 45 are formed side by side in the flow direction of lignite. In addition, each partition plate 43 is provided with a gap between it and the gas dispersion plate 6 of the second drying chamber 22, and this gap serves as a brown coal distribution port 46.

  Therefore, when the initially dried lignite is supplied from the first drying chamber 21, the supplied lignite is supplied via the flow port 46 between the partition plate 43 on the most upstream side in the flow direction and the gas dispersion plate 6. , And supplied to the drying compartment 45 on the most upstream side of the second drying chamber 22. The lignite supplied to the drying compartment 45 flows by the fluidizing gas supplied via the gas dispersion plate 6, thereby forming the fluidized bed 3. The lignite that has become the fluidized bed 3 is dried by the fluidizing gas. The lignite dried in the drying compartment 45 is pushed out to the drying compartment 45 on the downstream side through the flow port 46 between the partition plate 43 and the gas dispersion plate 6 on the downstream side in the flow direction. In this way, the lignite moves while being pushed out from the upstream drying compartment 45 to the downstream drying compartment 45 and passes through all the drying compartments 45, whereby late drying is performed.

  Thereby, the brown coal which forms the fluidized bed 3 of the 2nd drying chamber 22 can be made into an extrusion flow by moving the several drying compartment 45 in order from an upstream. Therefore, in the fluidized bed 3 in the 2nd drying chamber 22, the lignite which became the extrusion flow can be dried, without making it diffuse in a flow direction. At this time, the generated steam generated by drying the lignite is discharged from a steam discharge port 42 provided in the second drying chamber 22. Then, the lignite that has been subjected to late drying in the second drying chamber 22 becomes dry coal and is discharged from the discharge port 41. In the second drying chamber 22, for example, lignite having a moisture content of about 40% is dried late until the moisture content becomes about 10%.

  At this time, the first drying chamber 21 and the second drying chamber 22 have a floor area ratio, that is, an area ratio of the gas dispersion plate 6 in each of the chambers 21 and 22 is “first drying chamber: second drying chamber = 30-50%: 70-50% ".

  In addition, the fluidized bed drying apparatus 1 includes a recirculation line L through which the lignite discharged from the first drying chamber 21 flows again into the first drying chamber 21, and a foreign matter removing device (foreign matter removal) interposed in the recirculation line L. Means) 50 and a damming portion 51 for damaging a part of the lignite supplied to the second drying chamber 22.

  The recirculation line L has a lignite discharge port (fuel discharge port) 61 through which the lignite flows out from the first drying chamber 21, and a resupply port 62 for resupplying the lignite to the first drying chamber 21. The brown coal discharge port 61 is provided on the first drying chamber 21 side with the boundary portion between the first drying chamber 21 and the second drying chamber 22 interposed therebetween, and is provided on the gas distribution plate 6 serving as the bottom surface of the first drying chamber 21. It is connected. In other words, the lignite discharge port 61 is connected to the gas dispersion plate 6 serving as the bottom surface of the first drying chamber 21 on the downstream side in the flow direction. The resupply port 62 is formed on the side wall of the first drying chamber 21 on the upstream side in the flow direction of the lignite, and is substantially at the same position as the supply port 31. For this reason, the lignite discharged via the lignite discharge port 61 passes through the recirculation line L and is supplied again to the first drying chamber 21 via the resupply port 62.

  The damming portion 51 is provided on the second drying chamber 22 side with the boundary portion between the first drying chamber 21 and the second drying chamber 22 interposed therebetween, and is provided on the gas distribution plate 6 serving as the bottom surface of the second drying chamber 22. It has been. In other words, the damming portion 51 is provided on the gas dispersion plate 6 serving as the bottom surface of the second drying chamber 22 on the upstream side in the flow direction. As shown in FIG. 1, the damming portion 51 of the first embodiment is provided at the flow port 46 between the partition plate 43 and the gas dispersion plate 6 on the upstream side in the flow direction. May also be provided upstream.

  The foreign matter removing device 50 removes foreign matter contained in the brown coal passing through the recirculation line L. Examples of the foreign material include metal mixed with lignite, wood, or solid matter of coal formed by particle condensation. As the foreign substance removing device 50, for example, a cyclone type foreign substance removing device that can be separated by specific gravity can be applied.

  Therefore, a part of the lignite flowing in the first drying chamber 21 is dammed by the damming portion 51, and the lignite that has been dammed flows into the lignite discharge port 61 of the recirculation line L. The lignite after the initial drying that has flowed out of the first drying chamber 21 through the lignite discharge port 61 flows into the foreign matter removing device 50. The lignite that has flowed into the foreign matter removing device 50 is separated in the foreign matter removing device 50 into foreign matter and lignite from which the foreign matter has been removed. The separated foreign matter is discharged to the outside of the foreign matter removing device 50, and the lignite from which the foreign matter has been removed is supplied toward the resupply port 62 of the recirculation line L. Thereafter, the lignite from which the foreign matter has been removed is supplied to the upstream side of the first drying chamber 21 via the resupply port 62.

  As described above, according to the configuration of the first embodiment, the first drying chamber 21 can be dried by heating so that the moisture content of the supplied lignite becomes uniform by the completely mixed flow, and is homogenized. Brown lignite can be supplied to the second drying chamber 22. Moreover, in the 2nd drying chamber 22, it can heat-dry without diffusing the supplied lignite along a flow direction by extrusion flow. Thereby, since undried lignite becomes difficult to flow beyond dried lignite, discharge | emission of undried lignite can be suppressed and it becomes possible to fully dry lignite.

  Moreover, according to the structure of Example 1, the lignite supplied from the 1st drying chamber 21 toward the 2nd drying chamber 22 can be made to pass through all the drying compartments 45, and can be dried. Thereby, since a lignite can be dried in the some drying compartment 45 in order along a flow direction, a lignite can be fully dried over time.

  In addition, according to the configuration of the first embodiment, by providing the recirculation line L, it is possible to discharge the brown coal being dried from the first drying chamber 21 and supply it to the first drying chamber 21 again. For this reason, since the lignite after initial drying and the lignite before drying are supplied to the first drying chamber 21, the amount of lignite in the first drying chamber 21 is equivalent to the amount of lignite supplied after initial drying. Can promote drying. At this time, since the foreign matter removal device 50 is provided in the recirculation line L, foreign matters contained in the lignite flowing through the recirculation line L can be removed, so that the recirculation line L is prevented from being blocked by foreign matters. Can do.

  Moreover, according to the structure of Example 1, a part of lignite supplied from the 1st drying chamber 21 to the 2nd drying chamber 22 can be dammed by the damming part 51, and a part of the lignite that has been dammed up, It can flow into the lignite discharge port 61 of the recirculation line L. Thereby, the lignite flowing into the recirculation line L can be increased, and the drying of the lignite in the first drying chamber 21 can be further promoted.

  Moreover, according to the structure of Example 1, since the resupply port 62 was connected to the 1st drying chamber 21, the brown coal which passes the recirculation line L can be directly supplied to the 1st drying chamber 21. FIG.

  In Example 1, the re-supply port 62 of the recirculation line L is connected to the first drying chamber 21, but the configuration shown in FIG. FIG. 3 is a schematic configuration diagram schematically illustrating a fluidized bed drying apparatus according to the first modification. As shown in FIG. 3, the recirculation line L has a resupply port 62 connected to the raw coal bunker 121. For this reason, the lignite after the initial drying which flowed out from the lignite discharge port 61 of the recirculation line L is separated into the foreign matter and the lignite from which the foreign matter has been removed in the foreign matter removing device 50. Then, the lignite from which the foreign matter has been removed is supplied toward the resupply port 62 of the recirculation line L, and is supplied to the raw coal bunker 121 via the resupply port 62. Thereby, according to the structure of the modification 1, the coal which flows through the recirculation line L can be indirectly supplied to the 1st drying chamber 21 via the raw coal bunker 121. FIG.

  Next, with reference to FIG. 4, the fluidized bed drying apparatus 70 which concerns on Example 2 is demonstrated. FIG. 4 is a schematic configuration diagram schematically illustrating the fluidized bed drying apparatus according to the second embodiment. In the second embodiment, different parts will be described to avoid redundant description. In the fluidized bed drying apparatus 1 according to the first embodiment, the second drying chamber 22 of the drying furnace 5 is configured so that the supplied lignite becomes an extruded flow in the chamber, but the fluidized bed according to the second embodiment. In the drying apparatus 70, the second drying chamber 72 of the drying furnace 5 is configured such that the supplied lignite flows along the flow direction in the chamber, and in particular, configured to be an overflow flow (overflow). Yes. Hereinafter, the second drying chamber 72 of the drying furnace 5 in the fluidized bed drying apparatus 70 according to the second embodiment will be described with reference to FIG.

  The second drying chamber 72 is provided with a discharge port 41 through which brown coal is discharged, a steam discharge port 42 through which generated steam is discharged, and a plurality of partition plates 73. In addition, since the discharge port 41 and the steam discharge port 42 have the same configuration as in the first embodiment, description thereof is omitted.

  The some partition plate 73 is arrange | positioned at predetermined intervals in the flow direction of lignite. Each partition plate 73 is provided such that its plate surface is orthogonal to the flow direction. For this reason, the plurality of partition plates 43 divide the second drying chamber 22 into a plurality of drying compartments 75, and the plurality of drying compartments 75 are formed side by side in the flow direction of the lignite. In addition, each partition plate 73 is provided so as to be connected to the gas dispersion plate 6 of the second drying chamber 22, and the upper end portion thereof is located below the upper surface of the fluidized bed 3.

  Therefore, when the initially dried lignite is supplied from the first drying chamber 21, the supplied lignite exceeds the partition plate 73 on the most upstream side in the flow direction and is dried on the most upstream side of the second drying chamber 22. It flows into the compartment 75. The lignite that has flowed into the drying compartment 75 flows by the fluidizing gas supplied through the gas dispersion plate 6, thereby forming the fluidized bed 3. The lignite that has become the fluidized bed 3 is dried by the fluidizing gas. In the dry compartment 75, the dry lignite moves to the upper side of the dry compartment 75, while the undried lignite moves to the lower side of the dry compartment 75. The lignite dried in the drying compartment 75 overflows into the downstream drying compartment 75 over the downstream partition plate 73 in the flow direction. In this way, the lignite moves while overflowing from the upstream drying compartment 75 to the downstream drying compartment 75 and passes through all the drying compartments 75, whereby late drying is performed.

  As described above, according to the configuration of the second embodiment, the second drying chamber 72 can be dried by heating while flowing the supplied lignite along the flow direction due to the overflow flow. Thereby, the undried lignite moves to the lower side of the drying compartment 75, the dried lignite moves to the upper side of the drying compartment 75, and flows along the flow direction. For this reason, the fluidized-bed drying apparatus 70 of Example 2 can suppress the discharge | emission of the undried lignite, and it becomes possible to fully dry lignite.

DESCRIPTION OF SYMBOLS 1 Fluidized bed drying apparatus 3 Fluidized bed 5 Drying furnace 6 Gas dispersion | distribution plate 11 Chamber room 12 Drying room 21 1st drying room 22 2nd drying room 31 Supply port 33 Heat exchanger tube 41 Discharge port 42 Steam discharge port 43 Partition plate 45 Drying compartment 46 Distribution port 50 Foreign substance removal device 51 Damping part 61 Brown coal discharge port 62 Resupply port 70 Fluidized bed drying device (Example 2)
72 2nd drying chamber (Example 2)
73 Partition (Example 2)
75 Drying compartment (Example 2)
L Recirculation line

Claims (8)

Provided with a drying furnace that forms a fluidized bed inside by flowing wet fuel with fluidized gas,
The drying furnace is divided into a first drying chamber that performs initial drying of the wet fuel and a second drying chamber that performs late drying of the wet fuel supplied from the first drying chamber.
In the first drying chamber, the supplied wet fuel is dried in a completely mixed flow,
In the second drying chamber, the wet fuel supplied from the first drying chamber is dried while flowing along the flow direction of the wet fuel ,
A recirculation line that causes the wet fuel to flow out of the first drying chamber and flows the wet fuel back into the first drying chamber;
A fluidized bed drying apparatus comprising: a foreign matter removing unit that is provided in the recirculation line and removes foreign matter contained in the wet fuel passing through the recirculation line .   The fluidized bed drying apparatus according to claim 1, wherein the flow along the flow direction of the wet fuel is an extruded flow.   3. The fluidized bed drying apparatus according to claim 1, wherein the second drying chamber includes a plurality of drying compartments divided into a plurality in the flow direction of the wet fuel. The recirculation line has a fuel discharge port for allowing the wet fuel to flow out of the first drying chamber;
The fuel discharge port, across the boundary between the second drying chamber and the first drying chamber, claims 1, characterized in that it is connected to the bottom surface of the first drying chamber side 3 The fluidized bed drying apparatus according to any one of the above. The second drying chamber is provided with a damming portion on a bottom surface on the second drying chamber side with a boundary portion between the first drying chamber and the second drying chamber interposed therebetween. The fluidized bed drying apparatus according to claim 4 . The recirculation line has a resupply port for flowing in the wet fuel that has flowed out of the first drying chamber;
The fluidized bed drying apparatus according to any one of claims 1 to 5 , wherein the resupply port is connected to the first drying chamber. The recirculation line has a resupply port for flowing in the wet fuel that has flowed out of the first drying chamber;
The fluidized bed drying apparatus according to any one of claims 1 to 5 , wherein the resupply port is connected to a fuel bunker that stores the wet fuel supplied toward the first drying chamber. . The floor area ratio of the first drying chamber and the second drying chamber is “the first drying chamber: the second drying chamber = 30 to 50%: 70 to 50%”. The fluidized bed drying apparatus according to any one of claims 1 to 7 .

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