JP5748559B2 - 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.

  Conventionally, as such a fluidized bed drying apparatus, a fluidized dryer having a drying chamber which is a dispersible plate having a plurality of openings at the bottom and an air chamber located at the lower portion of the drying chamber is known. (For example, refer to Patent Document 1). This fluid dryer dries while flowing the material to be dried by supplying fluidizing gas (drying gas) from the wind chamber to the drying chamber through the dispersion plate, and the fluidization gas supplied to the drying chamber The gas is discharged from an exhaust port formed in the upper part of the drying chamber together with the vapor generated from the material to be dried.

JP 2008-89243 A

  By the way, in the structure of the fluidized bed drying apparatus as in the prior art, when recovering the latent heat of the fluidized gas and utilizing it effectively, it is preferable to use, for example, a condensable gas such as steam as the fluidized gas. However, when steam is used as the condensable gas, the steam temperature must be 100 ° C. or higher, and it is difficult to improve the drying efficiency.

  Accordingly, it is an object of the present invention to provide a fluidized bed drying apparatus capable of recovering the latent heat of fluidized gas so that it can be used effectively and improving the drying efficiency of wet fuel.

  The fluidized bed drying apparatus of the present invention includes a drying furnace that forms a fluidized bed by flowing a wet fuel with a fluidized gas, and the drying furnace is disposed upstream of the inside of the drying furnace in the flow direction of the wet fuel. A first drying chamber provided between a first drying chamber located on the side and a second drying chamber located on the downstream side of the first drying chamber; and a bottom portion and a partitioning portion of the drying furnace. And a fluidizing port for flowing the wet fuel from the first drying chamber to the second drying chamber, and the fluidizing gas includes a non-condensable gas and a condensable gas, and is one of the first drying chamber and the second drying chamber. On the other hand, a non-condensable gas is allowed to flow as a fluidizing gas, and a condensable gas is allowed to flow as a fluidizing gas into one of the first drying chamber and the second drying chamber.

According to this configuration, the non-condensable gas can be allowed to flow into either the first drying chamber or the second drying chamber. As the non-condensable gases, for example, nitrogen _{(N 2).} Nitrogen, which is a non-condensable gas, does not need to be 100 ° C. or higher unlike vapor, which is a condensable gas, and wet fuel can be dried at 70 ° C. to 100 ° C., improving the drying efficiency of wet fuel Can be made. On the other hand, since the condensable gas can flow into either one of the first drying chamber and the second drying chamber, the latent heat of the condensable gas can be recovered and effectively used.

  In this case, it is preferable that the non-condensable gas is allowed to flow into the first drying chamber and the condensable gas is allowed to flow into the second drying chamber.

  According to this configuration, the wet fuel in the first drying chamber located on the upstream side is undried compared to the wet fuel in the second drying chamber located on the downstream side, and the drying efficiency of the first drying chamber is reduced. By allowing a high non-condensable gas to flow in, the wet fuel can be efficiently dried.

  In this case, the pressure of either the first drying chamber or the second drying chamber into which the condensable gas flows is higher than the pressure of the other of the first drying chamber or the second drying chamber into which the non-condensable gas flows. Therefore, it is preferable that it is high.

  According to this configuration, the non-condensable gas does not flow into any one of the first drying chamber and the second drying chamber through which the condensable gas flows through the circulation port. Thereby, since it can suppress that non-condensable gas mixes in any one of the 1st drying chamber and the 2nd drying chamber into which condensable gas flows in, recovering condensable gas efficiently. Can do.

  In this case, the wet fuel dried in the drying furnace is supplied as the dry fuel, and is provided integrally with the drying furnace that cools the dry fuel while forming the fluidized bed inside by flowing the dry fuel with the fluidized gas. A cooling vessel is further provided, and the cooling vessel is provided therein with a cooling chamber communicating with the second drying chamber, and a non-condensable gas is preferably introduced into the cooling chamber as a fluidizing gas.

  According to this configuration, since the cooling container can be provided integrally with the drying furnace, the configuration can be simplified as compared with the case where the drying furnace and the cooling container are provided separately.

  In this case, it is further provided with a third gas discharge port provided in the cooling chamber for discharging the exhaust gas generated in the cooling chamber, and the pressure of the second drying chamber into which the condensable gas flows in is the cooling at which the non-condensable gas flows in. It is preferably higher than the pressure in the chamber.

  According to this configuration, the non-condensable gas flowing into the cooling chamber does not flow into the second drying chamber into which the condensable gas flows. Thereby, since it can suppress that noncondensable gas mixes in the 2nd drying chamber into which condensable gas flows in, condensable gas can be collect | recovered efficiently.

  In this case, the floor area ratio of the first drying chamber, the second drying chamber, and the cooling chamber is “first drying chamber: second drying chamber: cooling chamber = 27 to 45%: 63 to 45%: 10%”. It is preferable that

  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, and the wet fuel flowing in the cooling chamber can be cooled. Thereby, the wet fuel can be suitably dried in the first drying chamber and the second drying chamber, and the wet fuel can be suitably cooled in the cooling chamber.

  According to the fluidized bed drying apparatus of the present invention, the non-condensable gas is allowed to flow into one of the first drying chamber and the second drying chamber, and the condensation is performed on either one of the first drying chamber and the second drying chamber. Therefore, the latent heat of the fluidized gas can be recovered and used effectively, and the drying efficiency of the wet fuel can be improved.

FIG. 1 is a schematic configuration diagram of a coal gasification combined power generation facility to which a fluidized bed drying apparatus according to the present embodiment is applied. FIG. 2 is a schematic configuration diagram schematically illustrating the fluidized bed drying apparatus according to the present 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 combined coal gasification combined power generation facility to which a fluidized bed drying apparatus according to the present embodiment is applied. An integrated coal gasification combined cycle (IGCC) 100 to which the fluidized bed drying apparatus 1 of the present embodiment 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 coal gasification combined power generation facility 100 of the present 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 this example, lignite was applied as a wet raw material, but low-grade coal including subbituminous coal, 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 this embodiment, 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. Moreover, this fluidized bed drying apparatus 1 cools dried lignite (dry coal). The dried and cooled dry coal discharged from the fluidized bed drying apparatus 1 is stored in the dry 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 (exhaust gas) taken out from above, and the dry coal particles separated from the steam are provided. Is stored in the dry charcoal bunker 132. The steam from which the dry coal has been separated by the dry coal electrostatic precipitator 134 is supplied to an exhaust heat recovery boiler 120 described later, or compressed by the steam compressor 135 and then supplied to the fluidized bed drying apparatus 1 as drying steam. Or

  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. The coal gasification furnace 114 is provided with a foreign matter removing device 148 that removes foreign matter mixed in the 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 present embodiment will be described.

  In the coal gasification combined power generation facility 100 of the present 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, and stored in the dry coal bunker 132. Moreover, the steam taken out from the upper part of the fluidized bed drying apparatus 1 is separated into dry coal particles by a dry coal cyclone 133 and a dry coal electrostatic precipitator 134. The steam from which the dry coal is separated is supplied to the exhaust heat recovery boiler 120 or compressed by the steam compressor 135 and then returned to the fluidized bed drying apparatus 1 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 present embodiment. The fluidized bed drying apparatus 1 of the present embodiment heats and drys lignite, which is coal having a high water content, with fluidizing gas.

  The fluidized bed drying apparatus 1 includes a drying furnace 5 in which lignite is supplied, a cooling vessel 7 to which dried lignite is supplied, a gas distribution plate 6 provided inside the drying oven 5 and the cooling vessel 7, It is equipped with. The drying furnace 5 and the cooling container 7 are integrally provided, and the inside of the drying furnace 5 and the inside of the cooling container 7 communicate with each other. The gas distribution plate 6 includes a chamber chamber 11 located on the lower side (lower side in the drawing) of the drying furnace 5 and the cooling container 7, a drying chamber 12 located on the upper side (upper side in the drawing), and It is divided into a cooling chamber 13. A number of through holes are formed in the gas dispersion plate 6, and fluidized gas is introduced into the chamber chamber 11. The fluidizing gas includes nitrogen that is a non-condensable gas and steam that is a condensable gas.

  When lignite is supplied to the drying furnace 5, the supplied lignite 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 direction from the one end side (the left side in the figure) to the other end side (the right side in the figure) (the left-right direction in FIG. 2). Similarly, when the dried lignite is supplied to the cooling vessel 7, the supplied lignite flows by the fluidizing gas, thereby forming the fluidized bed 3 in the cooling vessel 7. The flow direction of the fluidized bed 3 formed in the cooling container 7 is a direction (left-right direction in FIG. 2) from one end side (left side in the figure) to the other end side (right side in the figure) of the cooling container 7. The drying furnace 5 is located upstream in the flow direction with respect to the cooling container 7, and the cooling container 7 is located downstream in the flow direction with respect to the drying furnace 5.

The chamber chamber 11 includes a first chamber chamber 14 on the upstream side in the flow direction, a second chamber chamber 15 on the downstream side of the first chamber chamber 14, and a third chamber chamber 16 on the downstream side of the second chamber chamber 15. A plurality (two) of chamber chamber partition walls 17 are provided. The first chamber chamber 14 is supplied with heated nitrogen (N ₂ ), which is a heated non-condensable gas, and the temperature is, for example, 70 ° C. to 100 ° C. The second chamber chamber 15 is supplied with drying steam such as superheated steam, which is a condensable gas, and has a temperature of 110 ° C. to 150 ° C., for example. The third chamber chamber 16 is supplied with cooled nitrogen (N ₂ ), which is a cooled non-condensable gas, and has a temperature of about 20 ° C., for example.

  The drying chamber 12 formed in the drying furnace 5 is divided into 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. Partition part) 25. The drying chamber partition 25 is provided with a gap between the drying chamber partition 25 and the gas dispersion plate 6, and this gap serves as a distribution port 28 for circulating lignite from the first drying chamber 21 toward the second drying chamber 22. . 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, a heat transfer tube 33 for heating the lignite, and a first gas discharge port 34 for discharging exhaust gas generated in the first drying chamber 21. It has been.

  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.

  The first gas discharge port 34 is connected to a first gas discharge port 38 formed on the upper surface of the first drying chamber 21. The first gas discharge port 34 discharges the generated steam generated by drying the heated nitrogen and lignite flowing into the first drying chamber 21 to the outside of the first drying chamber 21 as an exhaust gas.

  Therefore, when lignite is supplied from the supply port 31, the supplied lignite flows by the heated nitrogen supplied via the gas dispersion plate 6, thereby forming the fluidized bed 3. A first free board portion F1 is formed above the formed fluidized bed 3. The lignite that has become the fluidized bed 3 is initially dried by being heated by the heated nitrogen 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. 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 brown coal may become an extrusion flow along the flow direction in the chamber. 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 second gas discharge port 42 through which exhaust gas generated in the second drying chamber 22 is discharged, and a plurality of partition plates 43.

  The second gas discharge port 42 is connected to a second gas discharge port 44 formed on the upper surface of the second drying chamber 22. The second gas discharge port 42 discharges the superheated steam flowing into the second drying chamber 22 and the generated steam generated by drying the lignite to the outside of the second drying chamber 22 as exhaust gas. The exhaust gas discharged from the second gas discharge port 42 is supplied toward the dry coal cyclone 133 described above. For this reason, after the lignite is separated in the dry coal cyclone 133 and the dry coal electric dust collector 134, the exhaust gas discharged from the second gas discharge port 44 is part of the exhaust gas (superheated steam) after the lignite separation, The latent heat is recovered by the exhaust heat recovery boiler 120.

  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.

  Accordingly, when the initially dried lignite is supplied from the first drying chamber 21 through the distribution port 28, the supplied lignite is supplied to the most upstream drying compartment 45 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. A second free board portion F2 is formed above the formed 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. Then, the lignite that has been subjected to late drying in the second drying chamber 22 becomes dry coal and is supplied to the cooling chamber 13. 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%.

  The cooling chamber 13 cools the supplied dried lignite while flowing along the flow direction. A cooling chamber partition wall 48 is provided between the second drying chamber 22 and the cooling chamber 13 to separate them. The cooling chamber partition wall 48 is provided so as to form a gap with the gas dispersion plate 6, and this gap serves as a circulation port 49 through which lignite is circulated from the second drying chamber 22 toward the cooling chamber 13. The cooling chamber 13 is provided with a discharge port 41 for discharging lignite, a cooling pipe 51 for cooling lignite, and a third gas discharge port 52 for discharging exhaust gas generated in the cooling chamber 13.

  The discharge port 41 is formed at the bottom of the cooling chamber 13 on the downstream side in the flow direction of the lignite, and serves as a discharge port for discharging the lignite from the cooling chamber 13. In the discharge port 41, the brown coal cooled in the cooling chamber 13 is discharged as dry coal, and the discharged dry coal is supplied toward the dry coal bunker 132 described above.

  The cooling pipe 51 is provided inside the fluidized bed 3. The cooling pipe 51 is supplied with cooling water to cool the lignite in the fluidized bed 3. Therefore, when cooling water is supplied to the cooling pipe 51, the cooling pipe 51 cools the lignite in the cooling chamber 13 by removing heat from the lignite. Thereafter, the cooling water used for cooling is discharged to the outside of the cooling chamber 13.

  The third gas discharge port 52 is connected to a third gas discharge port 53 formed on the upper surface of the cooling chamber 13. The third gas discharge port 52 discharges the cooling nitrogen flowing into the cooling chamber 13 to the outside of the cooling chamber 13 as an exhaust gas.

  Therefore, when the lignite that has been dried late is supplied from the second drying chamber 22 through the circulation port 49, the supplied lignite is supplied to the cooling chamber 13. The lignite supplied to the cooling chamber 13 flows by the cooling nitrogen supplied via the gas dispersion plate 6, thereby forming the fluidized bed 3. A third free board portion F3 is formed above the formed fluidized bed 3. The lignite that has become the fluidized bed 3 is cooled by removing heat with cooling nitrogen. The lignite after cooling is discharged from the discharge port 41 toward the dry coal bunker 132 as dry coal.

  At this time, the first drying chamber 21, the second drying chamber 22, and the cooling chamber 13 have a floor area ratio, that is, an area ratio of the gas dispersion plate 6 in each of the chambers 21, 22, 13 is “first drying chamber”. : Second drying chamber: cooling chamber = 27 to 45%: 63 to 45%: 10%.

  Here, the pressure in the second drying chamber 22 to which superheated steam is supplied as the fluidizing gas is higher than the pressure in the first drying chamber 21 to which nitrogen is supplied as the fluidizing gas and the pressure in the cooling chamber 13. ing. For this reason, a part of the superheated steam that has flowed into the second drying chamber 22 through the gas dispersion plate 6 easily flows into the first drying chamber 21 through the flow port 28. On the other hand, a part of the heated nitrogen that has flowed into the first drying chamber 21 via the gas dispersion plate 6 tries to flow into the second drying chamber 22 via the circulation port 28, but the second drying chamber 22. Because of the high pressure, it becomes difficult to flow in.

  Similarly, a part of the superheated steam that has flowed into the second drying chamber 22 via the gas dispersion plate 6 easily flows into the cooling chamber 13 via the flow port 49. On the other hand, a part of the cooling nitrogen that has flowed into the cooling chamber 13 via the gas dispersion plate 6 tends to flow into the second drying chamber 22 via the flow port 49, but the pressure of the second drying chamber 22 It is difficult to flow in because of high.

  As described above, according to the configuration of the present embodiment, heated nitrogen that is a non-condensable gas can be caused to flow into the first drying chamber 21. Thereby, since lignite can be initially dried with heated nitrogen at 70 ° C to 100 ° C, the drying efficiency of lignite can be improved. On the other hand, superheated steam, which is a condensable gas, can flow into the second drying chamber 22. Thereby, since lignite can be dried in the latter stage with overheated steam at 110 ° C to 150 ° C, the latent heat of the condensable gas can be recovered and effectively used.

  Further, according to the configuration of the present embodiment, heated nitrogen can be flowed into the first drying chamber 21 and superheated steam can be flowed into the second drying chamber 22. For this reason, a non-condensable gas can be supplied with respect to the lignite of the 1st drying chamber 21 with a high moisture content, and lignite can be dried efficiently. Moreover, with respect to the lignite in the second drying chamber 22 in which the moisture content after the initial drying has decreased, the condensable gas can be supplied and the latent heat of the condensable gas can be recovered while drying the lignite.

  Further, according to the configuration of the present embodiment, the pressure of the second drying chamber 22 can be made higher than the pressures of the first drying chamber 21 and the cooling chamber 13. Thereby, since it can suppress that noncondensable gas mixes in the 2nd drying chamber 22, the latent heat of condensable gas can be collect | recovered efficiently.

  Further, according to the configuration of the present embodiment, the drying furnace 5 and the cooling vessel 7 can be provided integrally, so that the configuration is simpler than when the drying oven and the cooling vessel are provided separately. It can be.

  In this embodiment, cooling nitrogen is discharged as exhaust gas from the third gas discharge port 53, but the discharged cooling nitrogen may be supplied to the first chamber chamber 14 as heated nitrogen. According to this structure, since cooling nitrogen is heated at the time of heat removal of the lignite after drying, drying efficiency can further be improved by using the heated cooling nitrogen as heating nitrogen.

  In the present embodiment, heated nitrogen and generated steam are discharged as exhaust gas from the first gas discharge port 38, but the discharged generated steam is condensed and used as cooling water supplied to the cooling pipe 51. Also good. According to this structure, since the generated steam generated from lignite in the first drying chamber 21 can be effectively used, an improvement in cooling efficiency can be expected.

DESCRIPTION OF SYMBOLS 1 Fluidized bed drying apparatus 3 Fluidized bed 5 Drying furnace 6 Gas dispersion plate 7 Cooling container 11 Chamber room 12 Drying room 13 Cooling room 14 1st chamber room 15 2nd chamber room 16 3rd chamber room 17 Chamber chamber partition 21 First drying Chamber 22 Second drying chamber 25 Drying chamber partition 28 Flow port 31 Supply port 33 Heat transfer tube 34 First gas discharge port 38 First gas discharge port 41 Discharge port 42 Second gas discharge port 43 Partition plate 44 Second gas discharge port 45 Drying compartment 46 Distribution port 48 Cooling chamber partition 49 Distribution port 51 Cooling pipe 52 Third gas discharge port 53 Third gas discharge port F1 First freeboard section F2 Second freeboard section F3 Third freeboard section

Claims (4)

Provided with a drying furnace that forms a fluidized bed inside by flowing wet fuel with fluidized gas,
The drying furnace
A partition section that divides the inside of the drying furnace into a first drying chamber located on the upstream side in the flow direction of the wet fuel and a second drying chamber located on the downstream side of the first drying chamber;
A circulation port provided between the bottom of the drying furnace and the partition, and through which the wet fuel flows from the first drying chamber to the second drying chamber,
The fluidizing gas includes a non-condensable gas and a condensable gas,
The first drying chamber, said at Rukoto allowed to flow into the non-condensable gas as the fluidizing gas, the wet fuel is initially dry, the second drying chamber, flowing the condensable gas as the fluidizing gas in Rukoto it is, and the wet fuel by late dried,
Wherein during the initial drying of the wet fuel in the first drying chamber and during later drying the wet fuel in the second drying chamber, pressure force before the condensable gas flows Symbol second drying chamber, the non A fluidized bed drying apparatus characterized by being higher than the pressure in the first drying chamber into which condensable gas flows. The wet fuel dried in the drying furnace is supplied as a dry fuel, and is provided integrally with the drying furnace that cools the dry fuel while forming a fluidized bed inside by flowing the dry fuel with the fluidized gas. A cooling container provided,
The cooling container is provided with a cooling chamber communicating with the second drying chamber in the interior thereof.
Wherein the cooling chamber, said as a fluidizing gas, the fluidized bed dryer according to claim 1, characterized in that for flowing the non-condensable gases. A third gas discharge port provided in the cooling chamber and configured to discharge exhaust gas generated in the cooling chamber;
The fluidized bed drying apparatus according to claim 2 , wherein the pressure of the second drying chamber into which the condensable gas flows is higher than the pressure of the cooling chamber into which the non-condensable gas flows. The floor area ratio of the first drying chamber, the second drying chamber, and the cooling chamber is “the first drying chamber: the second drying chamber: the cooling chamber = 27 to 45%: 63 to 45%: fluidized bed dryer according to claim 2 or 3, characterized in that it is 10% ".

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